drivers/gpu/drm/display/drm_dp_mst_topology.c

   1 /*
   2  * Copyright © 2014 Red Hat
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <linux/bitfield.h>
  24 #include <linux/delay.h>
  25 #include <linux/errno.h>
  26 #include <linux/i2c.h>
  27 #include <linux/init.h>
  28 #include <linux/kernel.h>
  29 #include <linux/random.h>
  30 #include <linux/sched.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/iopoll.h>
  33
  34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
  35 #include <linux/stacktrace.h>
  36 #include <linux/sort.h>
  37 #include <linux/timekeeping.h>
  38 #include <linux/math64.h>
  39 #endif
  40
  41 #include <drm/display/drm_dp_mst_helper.h>
  42 #include <drm/drm_atomic.h>
  43 #include <drm/drm_atomic_helper.h>
  44 #include <drm/drm_drv.h>
  45 #include <drm/drm_edid.h>
  46 #include <drm/drm_fixed.h>
  47 #include <drm/drm_print.h>
  48 #include <drm/drm_probe_helper.h>
  49
  50 #include "drm_dp_helper_internal.h"
  51 #include "drm_dp_mst_topology_internal.h"
  52
  53 /**
  54  * DOC: dp mst helper
  55  *
  56  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  57  * protocol. The helpers contain a topology manager and bandwidth manager.
  58  * The helpers encapsulate the sending and received of sideband msgs.
  59  */
  60 struct drm_dp_pending_up_req {
  61         struct drm_dp_sideband_msg_hdr hdr;
  62         struct drm_dp_sideband_msg_req_body msg;
  63         struct list_head next;
  64 };
  65
  66 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  67                                   char *buf);
  68
  69 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  70
  71 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  72                                      int id, u8 start_slot, u8 num_slots);
  73
  74 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  75                                  struct drm_dp_mst_port *port,
  76                                  int offset, int size, u8 *bytes);
  77 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  78                                   struct drm_dp_mst_port *port,
  79                                   int offset, int size, u8 *bytes);
  80
  81 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  82                                     struct drm_dp_mst_branch *mstb);
  83
  84 static void
  85 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  86                                    struct drm_dp_mst_branch *mstb);
  87
  88 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  89                                            struct drm_dp_mst_branch *mstb,
  90                                            struct drm_dp_mst_port *port);
  91 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  92                                  u8 *guid);
  93
  94 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  95 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  96 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  97
  98 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  99                                                  struct drm_dp_mst_branch *branch);
 100
 101 #define DBG_PREFIX "[dp_mst]"
 102
 103 #define DP_STR(x) [DP_ ## x] = #x
 104
 105 static const char *drm_dp_mst_req_type_str(u8 req_type)
 106 {
 107         static const char * const req_type_str[] = {
 108                 DP_STR(GET_MSG_TRANSACTION_VERSION),
 109                 DP_STR(LINK_ADDRESS),
 110                 DP_STR(CONNECTION_STATUS_NOTIFY),
 111                 DP_STR(ENUM_PATH_RESOURCES),
 112                 DP_STR(ALLOCATE_PAYLOAD),
 113                 DP_STR(QUERY_PAYLOAD),
 114                 DP_STR(RESOURCE_STATUS_NOTIFY),
 115                 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 116                 DP_STR(REMOTE_DPCD_READ),
 117                 DP_STR(REMOTE_DPCD_WRITE),
 118                 DP_STR(REMOTE_I2C_READ),
 119                 DP_STR(REMOTE_I2C_WRITE),
 120                 DP_STR(POWER_UP_PHY),
 121                 DP_STR(POWER_DOWN_PHY),
 122                 DP_STR(SINK_EVENT_NOTIFY),
 123                 DP_STR(QUERY_STREAM_ENC_STATUS),
 124         };
 125
 126         if (req_type >= ARRAY_SIZE(req_type_str) ||
 127             !req_type_str[req_type])
 128                 return "unknown";
 129
 130         return req_type_str[req_type];
 131 }
 132
 133 #undef DP_STR
 134 #define DP_STR(x) [DP_NAK_ ## x] = #x
 135
 136 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 137 {
 138         static const char * const nak_reason_str[] = {
 139                 DP_STR(WRITE_FAILURE),
 140                 DP_STR(INVALID_READ),
 141                 DP_STR(CRC_FAILURE),
 142                 DP_STR(BAD_PARAM),
 143                 DP_STR(DEFER),
 144                 DP_STR(LINK_FAILURE),
 145                 DP_STR(NO_RESOURCES),
 146                 DP_STR(DPCD_FAIL),
 147                 DP_STR(I2C_NAK),
 148                 DP_STR(ALLOCATE_FAIL),
 149         };
 150
 151         if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 152             !nak_reason_str[nak_reason])
 153                 return "unknown";
 154
 155         return nak_reason_str[nak_reason];
 156 }
 157
 158 #undef DP_STR
 159 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 160
 161 static const char *drm_dp_mst_sideband_tx_state_str(int state)
 162 {
 163         static const char * const sideband_reason_str[] = {
 164                 DP_STR(QUEUED),
 165                 DP_STR(START_SEND),
 166                 DP_STR(SENT),
 167                 DP_STR(RX),
 168                 DP_STR(TIMEOUT),
 169         };
 170
 171         if (state >= ARRAY_SIZE(sideband_reason_str) ||
 172             !sideband_reason_str[state])
 173                 return "unknown";
 174
 175         return sideband_reason_str[state];
 176 }
 177
 178 static int
 179 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 180 {
 181         int i;
 182         u8 unpacked_rad[16];
 183
 184         for (i = 0; i < lct; i++) {
 185                 if (i % 2)
 186                         unpacked_rad[i] = rad[i / 2] >> 4;
 187                 else
 188                         unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 189         }
 190
 191         /* TODO: Eventually add something to printk so we can format the rad
 192          * like this: 1.2.3
 193          */
 194         return snprintf(out, len, "%*phC", lct, unpacked_rad);
 195 }
 196
 197 /* sideband msg handling */
 198 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 199 {
 200         u8 bitmask = 0x80;
 201         u8 bitshift = 7;
 202         u8 array_index = 0;
 203         int number_of_bits = num_nibbles * 4;
 204         u8 remainder = 0;
 205
 206         while (number_of_bits != 0) {
 207                 number_of_bits--;
 208                 remainder <<= 1;
 209                 remainder |= (data[array_index] & bitmask) >> bitshift;
 210                 bitmask >>= 1;
 211                 bitshift--;
 212                 if (bitmask == 0) {
 213                         bitmask = 0x80;
 214                         bitshift = 7;
 215                         array_index++;
 216                 }
 217                 if ((remainder & 0x10) == 0x10)
 218                         remainder ^= 0x13;
 219         }
 220
 221         number_of_bits = 4;
 222         while (number_of_bits != 0) {
 223                 number_of_bits--;
 224                 remainder <<= 1;
 225                 if ((remainder & 0x10) != 0)
 226                         remainder ^= 0x13;
 227         }
 228
 229         return remainder;
 230 }
 231
 232 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 233 {
 234         u8 bitmask = 0x80;
 235         u8 bitshift = 7;
 236         u8 array_index = 0;
 237         int number_of_bits = number_of_bytes * 8;
 238         u16 remainder = 0;
 239
 240         while (number_of_bits != 0) {
 241                 number_of_bits--;
 242                 remainder <<= 1;
 243                 remainder |= (data[array_index] & bitmask) >> bitshift;
 244                 bitmask >>= 1;
 245                 bitshift--;
 246                 if (bitmask == 0) {
 247                         bitmask = 0x80;
 248                         bitshift = 7;
 249                         array_index++;
 250                 }
 251                 if ((remainder & 0x100) == 0x100)
 252                         remainder ^= 0xd5;
 253         }
 254
 255         number_of_bits = 8;
 256         while (number_of_bits != 0) {
 257                 number_of_bits--;
 258                 remainder <<= 1;
 259                 if ((remainder & 0x100) != 0)
 260                         remainder ^= 0xd5;
 261         }
 262
 263         return remainder & 0xff;
 264 }
 265 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 266 {
 267         u8 size = 3;
 268
 269         size += (hdr->lct / 2);
 270         return size;
 271 }
 272
 273 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 274                                            u8 *buf, int *len)
 275 {
 276         int idx = 0;
 277         int i;
 278         u8 crc4;
 279
 280         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 281         for (i = 0; i < (hdr->lct / 2); i++)
 282                 buf[idx++] = hdr->rad[i];
 283         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 284                 (hdr->msg_len & 0x3f);
 285         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 286
 287         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 288         buf[idx - 1] |= (crc4 & 0xf);
 289
 290         *len = idx;
 291 }
 292
 293 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 294                                            struct drm_dp_sideband_msg_hdr *hdr,
 295                                            u8 *buf, int buflen, u8 *hdrlen)
 296 {
 297         u8 crc4;
 298         u8 len;
 299         int i;
 300         u8 idx;
 301
 302         if (buf[0] == 0)
 303                 return false;
 304         len = 3;
 305         len += ((buf[0] & 0xf0) >> 4) / 2;
 306         if (len > buflen)
 307                 return false;
 308         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 309
 310         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 311                 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 312                 return false;
 313         }
 314
 315         hdr->lct = (buf[0] & 0xf0) >> 4;
 316         hdr->lcr = (buf[0] & 0xf);
 317         idx = 1;
 318         for (i = 0; i < (hdr->lct / 2); i++)
 319                 hdr->rad[i] = buf[idx++];
 320         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 321         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 322         hdr->msg_len = buf[idx] & 0x3f;
 323         idx++;
 324         hdr->somt = (buf[idx] >> 7) & 0x1;
 325         hdr->eomt = (buf[idx] >> 6) & 0x1;
 326         hdr->seqno = (buf[idx] >> 4) & 0x1;
 327         idx++;
 328         *hdrlen = idx;
 329         return true;
 330 }
 331
 332 void
 333 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 334                            struct drm_dp_sideband_msg_tx *raw)
 335 {
 336         int idx = 0;
 337         int i;
 338         u8 *buf = raw->msg;
 339
 340         buf[idx++] = req->req_type & 0x7f;
 341
 342         switch (req->req_type) {
 343         case DP_ENUM_PATH_RESOURCES:
 344         case DP_POWER_DOWN_PHY:
 345         case DP_POWER_UP_PHY:
 346                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 347                 idx++;
 348                 break;
 349         case DP_ALLOCATE_PAYLOAD:
 350                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 351                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 352                 idx++;
 353                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 354                 idx++;
 355                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 356                 idx++;
 357                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 358                 idx++;
 359                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 360                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 361                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 362                         idx++;
 363                 }
 364                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 365                         i = req->u.allocate_payload.number_sdp_streams - 1;
 366                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 367                         idx++;
 368                 }
 369                 break;
 370         case DP_QUERY_PAYLOAD:
 371                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 372                 idx++;
 373                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 374                 idx++;
 375                 break;
 376         case DP_REMOTE_DPCD_READ:
 377                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 378                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 379                 idx++;
 380                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 381                 idx++;
 382                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 383                 idx++;
 384                 buf[idx] = (req->u.dpcd_read.num_bytes);
 385                 idx++;
 386                 break;
 387
 388         case DP_REMOTE_DPCD_WRITE:
 389                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 390                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 391                 idx++;
 392                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 393                 idx++;
 394                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 395                 idx++;
 396                 buf[idx] = (req->u.dpcd_write.num_bytes);
 397                 idx++;
 398                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 399                 idx += req->u.dpcd_write.num_bytes;
 400                 break;
 401         case DP_REMOTE_I2C_READ:
 402                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 403                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 404                 idx++;
 405                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 406                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 407                         idx++;
 408                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 409                         idx++;
 410                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 411                         idx += req->u.i2c_read.transactions[i].num_bytes;
 412
 413                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 414                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 415                         idx++;
 416                 }
 417                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 418                 idx++;
 419                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 420                 idx++;
 421                 break;
 422
 423         case DP_REMOTE_I2C_WRITE:
 424                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 425                 idx++;
 426                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 427                 idx++;
 428                 buf[idx] = (req->u.i2c_write.num_bytes);
 429                 idx++;
 430                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 431                 idx += req->u.i2c_write.num_bytes;
 432                 break;
 433         case DP_QUERY_STREAM_ENC_STATUS: {
 434                 const struct drm_dp_query_stream_enc_status *msg;
 435
 436                 msg = &req->u.enc_status;
 437                 buf[idx] = msg->stream_id;
 438                 idx++;
 439                 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 440                 idx += sizeof(msg->client_id);
 441                 buf[idx] = 0;
 442                 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 443                 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 444                 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 445                 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 446                 idx++;
 447                 }
 448                 break;
 449         }
 450         raw->cur_len = idx;
 451 }
 452 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 453
 454 /* Decode a sideband request we've encoded, mainly used for debugging */
 455 int
 456 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 457                            struct drm_dp_sideband_msg_req_body *req)
 458 {
 459         const u8 *buf = raw->msg;
 460         int i, idx = 0;
 461
 462         req->req_type = buf[idx++] & 0x7f;
 463         switch (req->req_type) {
 464         case DP_ENUM_PATH_RESOURCES:
 465         case DP_POWER_DOWN_PHY:
 466         case DP_POWER_UP_PHY:
 467                 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 468                 break;
 469         case DP_ALLOCATE_PAYLOAD:
 470                 {
 471                         struct drm_dp_allocate_payload *a =
 472                                 &req->u.allocate_payload;
 473
 474                         a->number_sdp_streams = buf[idx] & 0xf;
 475                         a->port_number = (buf[idx] >> 4) & 0xf;
 476
 477                         WARN_ON(buf[++idx] & 0x80);
 478                         a->vcpi = buf[idx] & 0x7f;
 479
 480                         a->pbn = buf[++idx] << 8;
 481                         a->pbn |= buf[++idx];
 482
 483                         idx++;
 484                         for (i = 0; i < a->number_sdp_streams; i++) {
 485                                 a->sdp_stream_sink[i] =
 486                                         (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 487                         }
 488                 }
 489                 break;
 490         case DP_QUERY_PAYLOAD:
 491                 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 492                 WARN_ON(buf[++idx] & 0x80);
 493                 req->u.query_payload.vcpi = buf[idx] & 0x7f;
 494                 break;
 495         case DP_REMOTE_DPCD_READ:
 496                 {
 497                         struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 498
 499                         r->port_number = (buf[idx] >> 4) & 0xf;
 500
 501                         r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 502                         r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 503                         r->dpcd_address |= buf[++idx] & 0xff;
 504
 505                         r->num_bytes = buf[++idx];
 506                 }
 507                 break;
 508         case DP_REMOTE_DPCD_WRITE:
 509                 {
 510                         struct drm_dp_remote_dpcd_write *w =
 511                                 &req->u.dpcd_write;
 512
 513                         w->port_number = (buf[idx] >> 4) & 0xf;
 514
 515                         w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 516                         w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 517                         w->dpcd_address |= buf[++idx] & 0xff;
 518
 519                         w->num_bytes = buf[++idx];
 520
 521                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 522                                            GFP_KERNEL);
 523                         if (!w->bytes)
 524                                 return -ENOMEM;
 525                 }
 526                 break;
 527         case DP_REMOTE_I2C_READ:
 528                 {
 529                         struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 530                         struct drm_dp_remote_i2c_read_tx *tx;
 531                         bool failed = false;
 532
 533                         r->num_transactions = buf[idx] & 0x3;
 534                         r->port_number = (buf[idx] >> 4) & 0xf;
 535                         for (i = 0; i < r->num_transactions; i++) {
 536                                 tx = &r->transactions[i];
 537
 538                                 tx->i2c_dev_id = buf[++idx] & 0x7f;
 539                                 tx->num_bytes = buf[++idx];
 540                                 tx->bytes = kmemdup(&buf[++idx],
 541                                                     tx->num_bytes,
 542                                                     GFP_KERNEL);
 543                                 if (!tx->bytes) {
 544                                         failed = true;
 545                                         break;
 546                                 }
 547                                 idx += tx->num_bytes;
 548                                 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 549                                 tx->i2c_transaction_delay = buf[idx] & 0xf;
 550                         }
 551
 552                         if (failed) {
 553                                 for (i = 0; i < r->num_transactions; i++) {
 554                                         tx = &r->transactions[i];
 555                                         kfree(tx->bytes);
 556                                 }
 557                                 return -ENOMEM;
 558                         }
 559
 560                         r->read_i2c_device_id = buf[++idx] & 0x7f;
 561                         r->num_bytes_read = buf[++idx];
 562                 }
 563                 break;
 564         case DP_REMOTE_I2C_WRITE:
 565                 {
 566                         struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 567
 568                         w->port_number = (buf[idx] >> 4) & 0xf;
 569                         w->write_i2c_device_id = buf[++idx] & 0x7f;
 570                         w->num_bytes = buf[++idx];
 571                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 572                                            GFP_KERNEL);
 573                         if (!w->bytes)
 574                                 return -ENOMEM;
 575                 }
 576                 break;
 577         case DP_QUERY_STREAM_ENC_STATUS:
 578                 req->u.enc_status.stream_id = buf[idx++];
 579                 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 580                         req->u.enc_status.client_id[i] = buf[idx++];
 581
 582                 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 583                                                            buf[idx]);
 584                 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 585                                                                  buf[idx]);
 586                 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 587                                                               buf[idx]);
 588                 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 589                                                                     buf[idx]);
 590                 break;
 591         }
 592
 593         return 0;
 594 }
 595 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 596
 597 void
 598 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 599                                   int indent, struct drm_printer *printer)
 600 {
 601         int i;
 602
 603 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 604         if (req->req_type == DP_LINK_ADDRESS) {
 605                 /* No contents to print */
 606                 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 607                 return;
 608         }
 609
 610         P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 611         indent++;
 612
 613         switch (req->req_type) {
 614         case DP_ENUM_PATH_RESOURCES:
 615         case DP_POWER_DOWN_PHY:
 616         case DP_POWER_UP_PHY:
 617                 P("port=%d\n", req->u.port_num.port_number);
 618                 break;
 619         case DP_ALLOCATE_PAYLOAD:
 620                 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 621                   req->u.allocate_payload.port_number,
 622                   req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 623                   req->u.allocate_payload.number_sdp_streams,
 624                   req->u.allocate_payload.number_sdp_streams,
 625                   req->u.allocate_payload.sdp_stream_sink);
 626                 break;
 627         case DP_QUERY_PAYLOAD:
 628                 P("port=%d vcpi=%d\n",
 629                   req->u.query_payload.port_number,
 630                   req->u.query_payload.vcpi);
 631                 break;
 632         case DP_REMOTE_DPCD_READ:
 633                 P("port=%d dpcd_addr=%05x len=%d\n",
 634                   req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 635                   req->u.dpcd_read.num_bytes);
 636                 break;
 637         case DP_REMOTE_DPCD_WRITE:
 638                 P("port=%d addr=%05x len=%d: %*ph\n",
 639                   req->u.dpcd_write.port_number,
 640                   req->u.dpcd_write.dpcd_address,
 641                   req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 642                   req->u.dpcd_write.bytes);
 643                 break;
 644         case DP_REMOTE_I2C_READ:
 645                 P("port=%d num_tx=%d id=%d size=%d:\n",
 646                   req->u.i2c_read.port_number,
 647                   req->u.i2c_read.num_transactions,
 648                   req->u.i2c_read.read_i2c_device_id,
 649                   req->u.i2c_read.num_bytes_read);
 650
 651                 indent++;
 652                 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 653                         const struct drm_dp_remote_i2c_read_tx *rtx =
 654                                 &req->u.i2c_read.transactions[i];
 655
 656                         P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 657                           i, rtx->i2c_dev_id, rtx->num_bytes,
 658                           rtx->no_stop_bit, rtx->i2c_transaction_delay,
 659                           rtx->num_bytes, rtx->bytes);
 660                 }
 661                 break;
 662         case DP_REMOTE_I2C_WRITE:
 663                 P("port=%d id=%d size=%d: %*ph\n",
 664                   req->u.i2c_write.port_number,
 665                   req->u.i2c_write.write_i2c_device_id,
 666                   req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 667                   req->u.i2c_write.bytes);
 668                 break;
 669         case DP_QUERY_STREAM_ENC_STATUS:
 670                 P("stream_id=%u client_id=%*ph stream_event=%x "
 671                   "valid_event=%d stream_behavior=%x valid_behavior=%d",
 672                   req->u.enc_status.stream_id,
 673                   (int)ARRAY_SIZE(req->u.enc_status.client_id),
 674                   req->u.enc_status.client_id, req->u.enc_status.stream_event,
 675                   req->u.enc_status.valid_stream_event,
 676                   req->u.enc_status.stream_behavior,
 677                   req->u.enc_status.valid_stream_behavior);
 678                 break;
 679         default:
 680                 P("???\n");
 681                 break;
 682         }
 683 #undef P
 684 }
 685 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 686
 687 static inline void
 688 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 689                                 const struct drm_dp_sideband_msg_tx *txmsg)
 690 {
 691         struct drm_dp_sideband_msg_req_body req;
 692         char buf[64];
 693         int ret;
 694         int i;
 695
 696         drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 697                               sizeof(buf));
 698         drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 699                    txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 700                    drm_dp_mst_sideband_tx_state_str(txmsg->state),
 701                    txmsg->path_msg, buf);
 702
 703         ret = drm_dp_decode_sideband_req(txmsg, &req);
 704         if (ret) {
 705                 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 706                 return;
 707         }
 708         drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 709
 710         switch (req.req_type) {
 711         case DP_REMOTE_DPCD_WRITE:
 712                 kfree(req.u.dpcd_write.bytes);
 713                 break;
 714         case DP_REMOTE_I2C_READ:
 715                 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 716                         kfree(req.u.i2c_read.transactions[i].bytes);
 717                 break;
 718         case DP_REMOTE_I2C_WRITE:
 719                 kfree(req.u.i2c_write.bytes);
 720                 break;
 721         }
 722 }
 723
 724 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 725 {
 726         u8 crc4;
 727
 728         crc4 = drm_dp_msg_data_crc4(msg, len);
 729         msg[len] = crc4;
 730 }
 731
 732 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 733                                          struct drm_dp_sideband_msg_tx *raw)
 734 {
 735         int idx = 0;
 736         u8 *buf = raw->msg;
 737
 738         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 739
 740         raw->cur_len = idx;
 741 }
 742
 743 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 744                                           struct drm_dp_sideband_msg_hdr *hdr,
 745                                           u8 hdrlen)
 746 {
 747         /*
 748          * ignore out-of-order messages or messages that are part of a
 749          * failed transaction
 750          */
 751         if (!hdr->somt && !msg->have_somt)
 752                 return false;
 753
 754         /* get length contained in this portion */
 755         msg->curchunk_idx = 0;
 756         msg->curchunk_len = hdr->msg_len;
 757         msg->curchunk_hdrlen = hdrlen;
 758
 759         /* we have already gotten an somt - don't bother parsing */
 760         if (hdr->somt && msg->have_somt)
 761                 return false;
 762
 763         if (hdr->somt) {
 764                 memcpy(&msg->initial_hdr, hdr,
 765                        sizeof(struct drm_dp_sideband_msg_hdr));
 766                 msg->have_somt = true;
 767         }
 768         if (hdr->eomt)
 769                 msg->have_eomt = true;
 770
 771         return true;
 772 }
 773
 774 /* this adds a chunk of msg to the builder to get the final msg */
 775 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 776                                            u8 *replybuf, u8 replybuflen)
 777 {
 778         u8 crc4;
 779
 780         memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 781         msg->curchunk_idx += replybuflen;
 782
 783         if (msg->curchunk_idx >= msg->curchunk_len) {
 784                 /* do CRC */
 785                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 786                 if (crc4 != msg->chunk[msg->curchunk_len - 1])
 787                         print_hex_dump(KERN_DEBUG, "wrong crc",
 788                                        DUMP_PREFIX_NONE, 16, 1,
 789                                        msg->chunk,  msg->curchunk_len, false);
 790                 /* copy chunk into bigger msg */
 791                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 792                 msg->curlen += msg->curchunk_len - 1;
 793         }
 794         return true;
 795 }
 796
 797 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 798                                                struct drm_dp_sideband_msg_rx *raw,
 799                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 800 {
 801         int idx = 1;
 802         int i;
 803
 804         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 805         idx += 16;
 806         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 807         idx++;
 808         if (idx > raw->curlen)
 809                 goto fail_len;
 810         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 811                 if (raw->msg[idx] & 0x80)
 812                         repmsg->u.link_addr.ports[i].input_port = 1;
 813
 814                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 815                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 816
 817                 idx++;
 818                 if (idx > raw->curlen)
 819                         goto fail_len;
 820                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 821                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 822                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 823                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 824                 idx++;
 825                 if (idx > raw->curlen)
 826                         goto fail_len;
 827                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 828                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 829                         idx++;
 830                         if (idx > raw->curlen)
 831                                 goto fail_len;
 832                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 833                         idx += 16;
 834                         if (idx > raw->curlen)
 835                                 goto fail_len;
 836                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 837                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 838                         idx++;
 839
 840                 }
 841                 if (idx > raw->curlen)
 842                         goto fail_len;
 843         }
 844
 845         return true;
 846 fail_len:
 847         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 848         return false;
 849 }
 850
 851 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 852                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 853 {
 854         int idx = 1;
 855
 856         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 857         idx++;
 858         if (idx > raw->curlen)
 859                 goto fail_len;
 860         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 861         idx++;
 862         if (idx > raw->curlen)
 863                 goto fail_len;
 864
 865         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 866         return true;
 867 fail_len:
 868         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 869         return false;
 870 }
 871
 872 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 873                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 874 {
 875         int idx = 1;
 876
 877         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 878         idx++;
 879         if (idx > raw->curlen)
 880                 goto fail_len;
 881         return true;
 882 fail_len:
 883         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 884         return false;
 885 }
 886
 887 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 888                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 889 {
 890         int idx = 1;
 891
 892         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 893         idx++;
 894         if (idx > raw->curlen)
 895                 goto fail_len;
 896         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 897         idx++;
 898         /* TODO check */
 899         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 900         return true;
 901 fail_len:
 902         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 903         return false;
 904 }
 905
 906 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 907                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 908 {
 909         int idx = 1;
 910
 911         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 912         repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 913         idx++;
 914         if (idx > raw->curlen)
 915                 goto fail_len;
 916         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 917         idx += 2;
 918         if (idx > raw->curlen)
 919                 goto fail_len;
 920         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 921         idx += 2;
 922         if (idx > raw->curlen)
 923                 goto fail_len;
 924         return true;
 925 fail_len:
 926         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 927         return false;
 928 }
 929
 930 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 931                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 932 {
 933         int idx = 1;
 934
 935         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 936         idx++;
 937         if (idx > raw->curlen)
 938                 goto fail_len;
 939         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 940         idx++;
 941         if (idx > raw->curlen)
 942                 goto fail_len;
 943         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 944         idx += 2;
 945         if (idx > raw->curlen)
 946                 goto fail_len;
 947         return true;
 948 fail_len:
 949         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 950         return false;
 951 }
 952
 953 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 954                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 955 {
 956         int idx = 1;
 957
 958         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 959         idx++;
 960         if (idx > raw->curlen)
 961                 goto fail_len;
 962         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 963         idx += 2;
 964         if (idx > raw->curlen)
 965                 goto fail_len;
 966         return true;
 967 fail_len:
 968         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 969         return false;
 970 }
 971
 972 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 973                                                        struct drm_dp_sideband_msg_reply_body *repmsg)
 974 {
 975         int idx = 1;
 976
 977         repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 978         idx++;
 979         if (idx > raw->curlen) {
 980                 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 981                               idx, raw->curlen);
 982                 return false;
 983         }
 984         return true;
 985 }
 986
 987 static bool
 988 drm_dp_sideband_parse_query_stream_enc_status(
 989                                 struct drm_dp_sideband_msg_rx *raw,
 990                                 struct drm_dp_sideband_msg_reply_body *repmsg)
 991 {
 992         struct drm_dp_query_stream_enc_status_ack_reply *reply;
 993
 994         reply = &repmsg->u.enc_status;
 995
 996         reply->stream_id = raw->msg[3];
 997
 998         reply->reply_signed = raw->msg[2] & BIT(0);
 999
1000         /*
1001          * NOTE: It's my impression from reading the spec that the below parsing
1002          * is correct. However I noticed while testing with an HDCP 1.4 display
1003          * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1004          * would expect both bits to be set. So keep the parsing following the
1005          * spec, but beware reality might not match the spec (at least for some
1006          * configurations).
1007          */
1008         reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1009         reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1010
1011         reply->query_capable_device_present = raw->msg[2] & BIT(5);
1012         reply->legacy_device_present = raw->msg[2] & BIT(6);
1013         reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1014
1015         reply->auth_completed = !!(raw->msg[1] & BIT(3));
1016         reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1017         reply->repeater_present = !!(raw->msg[1] & BIT(5));
1018         reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1019
1020         return true;
1021 }
1022
1023 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1024                                         struct drm_dp_sideband_msg_rx *raw,
1025                                         struct drm_dp_sideband_msg_reply_body *msg)
1026 {
1027         memset(msg, 0, sizeof(*msg));
1028         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1029         msg->req_type = (raw->msg[0] & 0x7f);
1030
1031         if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1032                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1033                 msg->u.nak.reason = raw->msg[17];
1034                 msg->u.nak.nak_data = raw->msg[18];
1035                 return false;
1036         }
1037
1038         switch (msg->req_type) {
1039         case DP_LINK_ADDRESS:
1040                 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1041         case DP_QUERY_PAYLOAD:
1042                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1043         case DP_REMOTE_DPCD_READ:
1044                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1045         case DP_REMOTE_DPCD_WRITE:
1046                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1047         case DP_REMOTE_I2C_READ:
1048                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1049         case DP_REMOTE_I2C_WRITE:
1050                 return true; /* since there's nothing to parse */
1051         case DP_ENUM_PATH_RESOURCES:
1052                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1053         case DP_ALLOCATE_PAYLOAD:
1054                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1055         case DP_POWER_DOWN_PHY:
1056         case DP_POWER_UP_PHY:
1057                 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1058         case DP_CLEAR_PAYLOAD_ID_TABLE:
1059                 return true; /* since there's nothing to parse */
1060         case DP_QUERY_STREAM_ENC_STATUS:
1061                 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1062         default:
1063                 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1064                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1065                 return false;
1066         }
1067 }
1068
1069 static bool
1070 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1071                                                struct drm_dp_sideband_msg_rx *raw,
1072                                                struct drm_dp_sideband_msg_req_body *msg)
1073 {
1074         int idx = 1;
1075
1076         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1077         idx++;
1078         if (idx > raw->curlen)
1079                 goto fail_len;
1080
1081         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1082         idx += 16;
1083         if (idx > raw->curlen)
1084                 goto fail_len;
1085
1086         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1087         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1088         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1089         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1090         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1091         idx++;
1092         return true;
1093 fail_len:
1094         drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1095                     idx, raw->curlen);
1096         return false;
1097 }
1098
1099 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1100                                                          struct drm_dp_sideband_msg_rx *raw,
1101                                                          struct drm_dp_sideband_msg_req_body *msg)
1102 {
1103         int idx = 1;
1104
1105         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1106         idx++;
1107         if (idx > raw->curlen)
1108                 goto fail_len;
1109
1110         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1111         idx += 16;
1112         if (idx > raw->curlen)
1113                 goto fail_len;
1114
1115         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1116         idx++;
1117         return true;
1118 fail_len:
1119         drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1120         return false;
1121 }
1122
1123 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1124                                       struct drm_dp_sideband_msg_rx *raw,
1125                                       struct drm_dp_sideband_msg_req_body *msg)
1126 {
1127         memset(msg, 0, sizeof(*msg));
1128         msg->req_type = (raw->msg[0] & 0x7f);
1129
1130         switch (msg->req_type) {
1131         case DP_CONNECTION_STATUS_NOTIFY:
1132                 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1133         case DP_RESOURCE_STATUS_NOTIFY:
1134                 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1135         default:
1136                 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1137                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1138                 return false;
1139         }
1140 }
1141
1142 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1143                              u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1144 {
1145         struct drm_dp_sideband_msg_req_body req;
1146
1147         req.req_type = DP_REMOTE_DPCD_WRITE;
1148         req.u.dpcd_write.port_number = port_num;
1149         req.u.dpcd_write.dpcd_address = offset;
1150         req.u.dpcd_write.num_bytes = num_bytes;
1151         req.u.dpcd_write.bytes = bytes;
1152         drm_dp_encode_sideband_req(&req, msg);
1153 }
1154
1155 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1156 {
1157         struct drm_dp_sideband_msg_req_body req;
1158
1159         req.req_type = DP_LINK_ADDRESS;
1160         drm_dp_encode_sideband_req(&req, msg);
1161 }
1162
1163 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1164 {
1165         struct drm_dp_sideband_msg_req_body req;
1166
1167         req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1168         drm_dp_encode_sideband_req(&req, msg);
1169         msg->path_msg = true;
1170 }
1171
1172 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1173                                      int port_num)
1174 {
1175         struct drm_dp_sideband_msg_req_body req;
1176
1177         req.req_type = DP_ENUM_PATH_RESOURCES;
1178         req.u.port_num.port_number = port_num;
1179         drm_dp_encode_sideband_req(&req, msg);
1180         msg->path_msg = true;
1181         return 0;
1182 }
1183
1184 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1185                                    int port_num,
1186                                    u8 vcpi, uint16_t pbn,
1187                                    u8 number_sdp_streams,
1188                                    u8 *sdp_stream_sink)
1189 {
1190         struct drm_dp_sideband_msg_req_body req;
1191
1192         memset(&req, 0, sizeof(req));
1193         req.req_type = DP_ALLOCATE_PAYLOAD;
1194         req.u.allocate_payload.port_number = port_num;
1195         req.u.allocate_payload.vcpi = vcpi;
1196         req.u.allocate_payload.pbn = pbn;
1197         req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1198         memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1199                    number_sdp_streams);
1200         drm_dp_encode_sideband_req(&req, msg);
1201         msg->path_msg = true;
1202 }
1203
1204 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1205                                    int port_num, bool power_up)
1206 {
1207         struct drm_dp_sideband_msg_req_body req;
1208
1209         if (power_up)
1210                 req.req_type = DP_POWER_UP_PHY;
1211         else
1212                 req.req_type = DP_POWER_DOWN_PHY;
1213
1214         req.u.port_num.port_number = port_num;
1215         drm_dp_encode_sideband_req(&req, msg);
1216         msg->path_msg = true;
1217 }
1218
1219 static int
1220 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1221                               u8 *q_id)
1222 {
1223         struct drm_dp_sideband_msg_req_body req;
1224
1225         req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1226         req.u.enc_status.stream_id = stream_id;
1227         memcpy(req.u.enc_status.client_id, q_id,
1228                sizeof(req.u.enc_status.client_id));
1229         req.u.enc_status.stream_event = 0;
1230         req.u.enc_status.valid_stream_event = false;
1231         req.u.enc_status.stream_behavior = 0;
1232         req.u.enc_status.valid_stream_behavior = false;
1233
1234         drm_dp_encode_sideband_req(&req, msg);
1235         return 0;
1236 }
1237
1238 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1239                               struct drm_dp_sideband_msg_tx *txmsg)
1240 {
1241         unsigned int state;
1242
1243         /*
1244          * All updates to txmsg->state are protected by mgr->qlock, and the two
1245          * cases we check here are terminal states. For those the barriers
1246          * provided by the wake_up/wait_event pair are enough.
1247          */
1248         state = READ_ONCE(txmsg->state);
1249         return (state == DRM_DP_SIDEBAND_TX_RX ||
1250                 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1251 }
1252
1253 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1254                                     struct drm_dp_sideband_msg_tx *txmsg)
1255 {
1256         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1257         unsigned long wait_timeout = msecs_to_jiffies(4000);
1258         unsigned long wait_expires = jiffies + wait_timeout;
1259         int ret;
1260
1261         for (;;) {
1262                 /*
1263                  * If the driver provides a way for this, change to
1264                  * poll-waiting for the MST reply interrupt if we didn't receive
1265                  * it for 50 msec. This would cater for cases where the HPD
1266                  * pulse signal got lost somewhere, even though the sink raised
1267                  * the corresponding MST interrupt correctly. One example is the
1268                  * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1269                  * filters out short pulses with a duration less than ~540 usec.
1270                  *
1271                  * The poll period is 50 msec to avoid missing an interrupt
1272                  * after the sink has cleared it (after a 110msec timeout
1273                  * since it raised the interrupt).
1274                  */
1275                 ret = wait_event_timeout(mgr->tx_waitq,
1276                                          check_txmsg_state(mgr, txmsg),
1277                                          mgr->cbs->poll_hpd_irq ?
1278                                                 msecs_to_jiffies(50) :
1279                                                 wait_timeout);
1280
1281                 if (ret || !mgr->cbs->poll_hpd_irq ||
1282                     time_after(jiffies, wait_expires))
1283                         break;
1284
1285                 mgr->cbs->poll_hpd_irq(mgr);
1286         }
1287
1288         mutex_lock(&mgr->qlock);
1289         if (ret > 0) {
1290                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1291                         ret = -EIO;
1292                         goto out;
1293                 }
1294         } else {
1295                 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1296                             txmsg, txmsg->state, txmsg->seqno);
1297
1298                 /* dump some state */
1299                 ret = -EIO;
1300
1301                 /* remove from q */
1302                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1303                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1304                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1305                         list_del(&txmsg->next);
1306         }
1307 out:
1308         if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1309                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1310
1311                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1312         }
1313         mutex_unlock(&mgr->qlock);
1314
1315         drm_dp_mst_kick_tx(mgr);
1316         return ret;
1317 }
1318
1319 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1320 {
1321         struct drm_dp_mst_branch *mstb;
1322
1323         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1324         if (!mstb)
1325                 return NULL;
1326
1327         mstb->lct = lct;
1328         if (lct > 1)
1329                 memcpy(mstb->rad, rad, lct / 2);
1330         INIT_LIST_HEAD(&mstb->ports);
1331         kref_init(&mstb->topology_kref);
1332         kref_init(&mstb->malloc_kref);
1333         return mstb;
1334 }
1335
1336 static void drm_dp_free_mst_branch_device(struct kref *kref)
1337 {
1338         struct drm_dp_mst_branch *mstb =
1339                 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1340
1341         if (mstb->port_parent)
1342                 drm_dp_mst_put_port_malloc(mstb->port_parent);
1343
1344         kfree(mstb);
1345 }
1346
1347 /**
1348  * DOC: Branch device and port refcounting
1349  *
1350  * Topology refcount overview
1351  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1352  *
1353  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1354  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1355  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1356  *
1357  * Topology refcounts are not exposed to drivers, and are handled internally
1358  * by the DP MST helpers. The helpers use them in order to prevent the
1359  * in-memory topology state from being changed in the middle of critical
1360  * operations like changing the internal state of payload allocations. This
1361  * means each branch and port will be considered to be connected to the rest
1362  * of the topology until its topology refcount reaches zero. Additionally,
1363  * for ports this means that their associated &struct drm_connector will stay
1364  * registered with userspace until the port's refcount reaches 0.
1365  *
1366  * Malloc refcount overview
1367  * ~~~~~~~~~~~~~~~~~~~~~~~~
1368  *
1369  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1370  * drm_dp_mst_branch allocated even after all of its topology references have
1371  * been dropped, so that the driver or MST helpers can safely access each
1372  * branch's last known state before it was disconnected from the topology.
1373  * When the malloc refcount of a port or branch reaches 0, the memory
1374  * allocation containing the &struct drm_dp_mst_branch or &struct
1375  * drm_dp_mst_port respectively will be freed.
1376  *
1377  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1378  * to drivers. As of writing this documentation, there are no drivers that
1379  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1380  * helpers. Exposing this API to drivers in a race-free manner would take more
1381  * tweaking of the refcounting scheme, however patches are welcome provided
1382  * there is a legitimate driver usecase for this.
1383  *
1384  * Refcount relationships in a topology
1385  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1386  *
1387  * Let's take a look at why the relationship between topology and malloc
1388  * refcounts is designed the way it is.
1389  *
1390  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1391  *
1392  *    An example of topology and malloc refs in a DP MST topology with two
1393  *    active payloads. Topology refcount increments are indicated by solid
1394  *    lines, and malloc refcount increments are indicated by dashed lines.
1395  *    Each starts from the branch which incremented the refcount, and ends at
1396  *    the branch to which the refcount belongs to, i.e. the arrow points the
1397  *    same way as the C pointers used to reference a structure.
1398  *
1399  * As you can see in the above figure, every branch increments the topology
1400  * refcount of its children, and increments the malloc refcount of its
1401  * parent. Additionally, every payload increments the malloc refcount of its
1402  * assigned port by 1.
1403  *
1404  * So, what would happen if MSTB #3 from the above figure was unplugged from
1405  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1406  * topology would start to look like the figure below.
1407  *
1408  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1409  *
1410  *    Ports and branch devices which have been released from memory are
1411  *    colored grey, and references which have been removed are colored red.
1412  *
1413  * Whenever a port or branch device's topology refcount reaches zero, it will
1414  * decrement the topology refcounts of all its children, the malloc refcount
1415  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1416  * #4, this means they both have been disconnected from the topology and freed
1417  * from memory. But, because payload #2 is still holding a reference to port
1418  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1419  * is still accessible from memory. This also means port #3 has not yet
1420  * decremented the malloc refcount of MSTB #3, so its &struct
1421  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1422  * malloc refcount reaches 0.
1423  *
1424  * This relationship is necessary because in order to release payload #2, we
1425  * need to be able to figure out the last relative of port #3 that's still
1426  * connected to the topology. In this case, we would travel up the topology as
1427  * shown below.
1428  *
1429  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1430  *
1431  * And finally, remove payload #2 by communicating with port #2 through
1432  * sideband transactions.
1433  */
1434
1435 /**
1436  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1437  * device
1438  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1439  *
1440  * Increments &drm_dp_mst_branch.malloc_kref. When
1441  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1442  * will be released and @mstb may no longer be used.
1443  *
1444  * See also: drm_dp_mst_put_mstb_malloc()
1445  */
1446 static void
1447 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1448 {
1449         kref_get(&mstb->malloc_kref);
1450         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1451 }
1452
1453 /**
1454  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1455  * device
1456  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1457  *
1458  * Decrements &drm_dp_mst_branch.malloc_kref. When
1459  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1460  * will be released and @mstb may no longer be used.
1461  *
1462  * See also: drm_dp_mst_get_mstb_malloc()
1463  */
1464 static void
1465 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1466 {
1467         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1468         kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1469 }
1470
1471 static void drm_dp_free_mst_port(struct kref *kref)
1472 {
1473         struct drm_dp_mst_port *port =
1474                 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1475
1476         drm_dp_mst_put_mstb_malloc(port->parent);
1477         kfree(port);
1478 }
1479
1480 /**
1481  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1482  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1483  *
1484  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1485  * reaches 0, the memory allocation for @port will be released and @port may
1486  * no longer be used.
1487  *
1488  * Because @port could potentially be freed at any time by the DP MST helpers
1489  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1490  * function, drivers that which to make use of &struct drm_dp_mst_port should
1491  * ensure that they grab at least one main malloc reference to their MST ports
1492  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1493  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1494  *
1495  * See also: drm_dp_mst_put_port_malloc()
1496  */
1497 void
1498 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1499 {
1500         kref_get(&port->malloc_kref);
1501         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1502 }
1503 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1504
1505 /**
1506  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1507  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1508  *
1509  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1510  * reaches 0, the memory allocation for @port will be released and @port may
1511  * no longer be used.
1512  *
1513  * See also: drm_dp_mst_get_port_malloc()
1514  */
1515 void
1516 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1517 {
1518         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1519         kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1520 }
1521 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1522
1523 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1524
1525 #define STACK_DEPTH 8
1526
1527 static noinline void
1528 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1529                     struct drm_dp_mst_topology_ref_history *history,
1530                     enum drm_dp_mst_topology_ref_type type)
1531 {
1532         struct drm_dp_mst_topology_ref_entry *entry = NULL;
1533         depot_stack_handle_t backtrace;
1534         ulong stack_entries[STACK_DEPTH];
1535         uint n;
1536         int i;
1537
1538         n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1539         backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1540         if (!backtrace)
1541                 return;
1542
1543         /* Try to find an existing entry for this backtrace */
1544         for (i = 0; i < history->len; i++) {
1545                 if (history->entries[i].backtrace == backtrace) {
1546                         entry = &history->entries[i];
1547                         break;
1548                 }
1549         }
1550
1551         /* Otherwise add one */
1552         if (!entry) {
1553                 struct drm_dp_mst_topology_ref_entry *new;
1554                 int new_len = history->len + 1;
1555
1556                 new = krealloc(history->entries, sizeof(*new) * new_len,
1557                                GFP_KERNEL);
1558                 if (!new)
1559                         return;
1560
1561                 entry = &new[history->len];
1562                 history->len = new_len;
1563                 history->entries = new;
1564
1565                 entry->backtrace = backtrace;
1566                 entry->type = type;
1567                 entry->count = 0;
1568         }
1569         entry->count++;
1570         entry->ts_nsec = ktime_get_ns();
1571 }
1572
1573 static int
1574 topology_ref_history_cmp(const void *a, const void *b)
1575 {
1576         const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1577
1578         if (entry_a->ts_nsec > entry_b->ts_nsec)
1579                 return 1;
1580         else if (entry_a->ts_nsec < entry_b->ts_nsec)
1581                 return -1;
1582         else
1583                 return 0;
1584 }
1585
1586 static inline const char *
1587 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1588 {
1589         if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1590                 return "get";
1591         else
1592                 return "put";
1593 }
1594
1595 static void
1596 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1597                             void *ptr, const char *type_str)
1598 {
1599         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1600         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1601         int i;
1602
1603         if (!buf)
1604                 return;
1605
1606         if (!history->len)
1607                 goto out;
1608
1609         /* First, sort the list so that it goes from oldest to newest
1610          * reference entry
1611          */
1612         sort(history->entries, history->len, sizeof(*history->entries),
1613              topology_ref_history_cmp, NULL);
1614
1615         drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1616                    type_str, ptr);
1617
1618         for (i = 0; i < history->len; i++) {
1619                 const struct drm_dp_mst_topology_ref_entry *entry =
1620                         &history->entries[i];
1621                 u64 ts_nsec = entry->ts_nsec;
1622                 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1623
1624                 stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1625
1626                 drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1627                            entry->count,
1628                            topology_ref_type_to_str(entry->type),
1629                            ts_nsec, rem_nsec / 1000, buf);
1630         }
1631
1632         /* Now free the history, since this is the only time we expose it */
1633         kfree(history->entries);
1634 out:
1635         kfree(buf);
1636 }
1637
1638 static __always_inline void
1639 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1640 {
1641         __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1642                                     "MSTB");
1643 }
1644
1645 static __always_inline void
1646 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1647 {
1648         __dump_topology_ref_history(&port->topology_ref_history, port,
1649                                     "Port");
1650 }
1651
1652 static __always_inline void
1653 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1654                        enum drm_dp_mst_topology_ref_type type)
1655 {
1656         __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1657 }
1658
1659 static __always_inline void
1660 save_port_topology_ref(struct drm_dp_mst_port *port,
1661                        enum drm_dp_mst_topology_ref_type type)
1662 {
1663         __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1664 }
1665
1666 static inline void
1667 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1668 {
1669         mutex_lock(&mgr->topology_ref_history_lock);
1670 }
1671
1672 static inline void
1673 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1674 {
1675         mutex_unlock(&mgr->topology_ref_history_lock);
1676 }
1677 #else
1678 static inline void
1679 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1680 static inline void
1681 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1682 static inline void
1683 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1684 static inline void
1685 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1686 #define save_mstb_topology_ref(mstb, type)
1687 #define save_port_topology_ref(port, type)
1688 #endif
1689
1690 struct drm_dp_mst_atomic_payload *
1691 drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
1692                                  struct drm_dp_mst_port *port)
1693 {
1694         struct drm_dp_mst_atomic_payload *payload;
1695
1696         list_for_each_entry(payload, &state->payloads, next)
1697                 if (payload->port == port)
1698                         return payload;
1699
1700         return NULL;
1701 }
1702 EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
1703
1704 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1705 {
1706         struct drm_dp_mst_branch *mstb =
1707                 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1708         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1709
1710         drm_dp_mst_dump_mstb_topology_history(mstb);
1711
1712         INIT_LIST_HEAD(&mstb->destroy_next);
1713
1714         /*
1715          * This can get called under mgr->mutex, so we need to perform the
1716          * actual destruction of the mstb in another worker
1717          */
1718         mutex_lock(&mgr->delayed_destroy_lock);
1719         list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1720         mutex_unlock(&mgr->delayed_destroy_lock);
1721         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1722 }
1723
1724 /**
1725  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1726  * branch device unless it's zero
1727  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1728  *
1729  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1730  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1731  * reached 0). Holding a topology reference implies that a malloc reference
1732  * will be held to @mstb as long as the user holds the topology reference.
1733  *
1734  * Care should be taken to ensure that the user has at least one malloc
1735  * reference to @mstb. If you already have a topology reference to @mstb, you
1736  * should use drm_dp_mst_topology_get_mstb() instead.
1737  *
1738  * See also:
1739  * drm_dp_mst_topology_get_mstb()
1740  * drm_dp_mst_topology_put_mstb()
1741  *
1742  * Returns:
1743  * * 1: A topology reference was grabbed successfully
1744  * * 0: @port is no longer in the topology, no reference was grabbed
1745  */
1746 static int __must_check
1747 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1748 {
1749         int ret;
1750
1751         topology_ref_history_lock(mstb->mgr);
1752         ret = kref_get_unless_zero(&mstb->topology_kref);
1753         if (ret) {
1754                 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1755                 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1756         }
1757
1758         topology_ref_history_unlock(mstb->mgr);
1759
1760         return ret;
1761 }
1762
1763 /**
1764  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1765  * branch device
1766  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1767  *
1768  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1769  * not it's already reached 0. This is only valid to use in scenarios where
1770  * you are already guaranteed to have at least one active topology reference
1771  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1772  *
1773  * See also:
1774  * drm_dp_mst_topology_try_get_mstb()
1775  * drm_dp_mst_topology_put_mstb()
1776  */
1777 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1778 {
1779         topology_ref_history_lock(mstb->mgr);
1780
1781         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1782         WARN_ON(kref_read(&mstb->topology_kref) == 0);
1783         kref_get(&mstb->topology_kref);
1784         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1785
1786         topology_ref_history_unlock(mstb->mgr);
1787 }
1788
1789 /**
1790  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1791  * device
1792  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1793  *
1794  * Releases a topology reference from @mstb by decrementing
1795  * &drm_dp_mst_branch.topology_kref.
1796  *
1797  * See also:
1798  * drm_dp_mst_topology_try_get_mstb()
1799  * drm_dp_mst_topology_get_mstb()
1800  */
1801 static void
1802 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1803 {
1804         topology_ref_history_lock(mstb->mgr);
1805
1806         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1807         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1808
1809         topology_ref_history_unlock(mstb->mgr);
1810         kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1811 }
1812
1813 static void drm_dp_destroy_port(struct kref *kref)
1814 {
1815         struct drm_dp_mst_port *port =
1816                 container_of(kref, struct drm_dp_mst_port, topology_kref);
1817         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1818
1819         drm_dp_mst_dump_port_topology_history(port);
1820
1821         /* There's nothing that needs locking to destroy an input port yet */
1822         if (port->input) {
1823                 drm_dp_mst_put_port_malloc(port);
1824                 return;
1825         }
1826
1827         drm_edid_free(port->cached_edid);
1828
1829         /*
1830          * we can't destroy the connector here, as we might be holding the
1831          * mode_config.mutex from an EDID retrieval
1832          */
1833         mutex_lock(&mgr->delayed_destroy_lock);
1834         list_add(&port->next, &mgr->destroy_port_list);
1835         mutex_unlock(&mgr->delayed_destroy_lock);
1836         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1837 }
1838
1839 /**
1840  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1841  * port unless it's zero
1842  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1843  *
1844  * Attempts to grab a topology reference to @port, if it hasn't yet been
1845  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1846  * 0). Holding a topology reference implies that a malloc reference will be
1847  * held to @port as long as the user holds the topology reference.
1848  *
1849  * Care should be taken to ensure that the user has at least one malloc
1850  * reference to @port. If you already have a topology reference to @port, you
1851  * should use drm_dp_mst_topology_get_port() instead.
1852  *
1853  * See also:
1854  * drm_dp_mst_topology_get_port()
1855  * drm_dp_mst_topology_put_port()
1856  *
1857  * Returns:
1858  * * 1: A topology reference was grabbed successfully
1859  * * 0: @port is no longer in the topology, no reference was grabbed
1860  */
1861 static int __must_check
1862 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1863 {
1864         int ret;
1865
1866         topology_ref_history_lock(port->mgr);
1867         ret = kref_get_unless_zero(&port->topology_kref);
1868         if (ret) {
1869                 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1870                 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1871         }
1872
1873         topology_ref_history_unlock(port->mgr);
1874         return ret;
1875 }
1876
1877 /**
1878  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1879  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1880  *
1881  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1882  * not it's already reached 0. This is only valid to use in scenarios where
1883  * you are already guaranteed to have at least one active topology reference
1884  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1885  *
1886  * See also:
1887  * drm_dp_mst_topology_try_get_port()
1888  * drm_dp_mst_topology_put_port()
1889  */
1890 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1891 {
1892         topology_ref_history_lock(port->mgr);
1893
1894         WARN_ON(kref_read(&port->topology_kref) == 0);
1895         kref_get(&port->topology_kref);
1896         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1897         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1898
1899         topology_ref_history_unlock(port->mgr);
1900 }
1901
1902 /**
1903  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1904  * @port: The &struct drm_dp_mst_port to release the topology reference from
1905  *
1906  * Releases a topology reference from @port by decrementing
1907  * &drm_dp_mst_port.topology_kref.
1908  *
1909  * See also:
1910  * drm_dp_mst_topology_try_get_port()
1911  * drm_dp_mst_topology_get_port()
1912  */
1913 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1914 {
1915         topology_ref_history_lock(port->mgr);
1916
1917         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1918         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1919
1920         topology_ref_history_unlock(port->mgr);
1921         kref_put(&port->topology_kref, drm_dp_destroy_port);
1922 }
1923
1924 static struct drm_dp_mst_branch *
1925 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1926                                               struct drm_dp_mst_branch *to_find)
1927 {
1928         struct drm_dp_mst_port *port;
1929         struct drm_dp_mst_branch *rmstb;
1930
1931         if (to_find == mstb)
1932                 return mstb;
1933
1934         list_for_each_entry(port, &mstb->ports, next) {
1935                 if (port->mstb) {
1936                         rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1937                             port->mstb, to_find);
1938                         if (rmstb)
1939                                 return rmstb;
1940                 }
1941         }
1942         return NULL;
1943 }
1944
1945 static struct drm_dp_mst_branch *
1946 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1947                                        struct drm_dp_mst_branch *mstb)
1948 {
1949         struct drm_dp_mst_branch *rmstb = NULL;
1950
1951         mutex_lock(&mgr->lock);
1952         if (mgr->mst_primary) {
1953                 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1954                     mgr->mst_primary, mstb);
1955
1956                 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1957                         rmstb = NULL;
1958         }
1959         mutex_unlock(&mgr->lock);
1960         return rmstb;
1961 }
1962
1963 static struct drm_dp_mst_port *
1964 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1965                                               struct drm_dp_mst_port *to_find)
1966 {
1967         struct drm_dp_mst_port *port, *mport;
1968
1969         list_for_each_entry(port, &mstb->ports, next) {
1970                 if (port == to_find)
1971                         return port;
1972
1973                 if (port->mstb) {
1974                         mport = drm_dp_mst_topology_get_port_validated_locked(
1975                             port->mstb, to_find);
1976                         if (mport)
1977                                 return mport;
1978                 }
1979         }
1980         return NULL;
1981 }
1982
1983 static struct drm_dp_mst_port *
1984 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1985                                        struct drm_dp_mst_port *port)
1986 {
1987         struct drm_dp_mst_port *rport = NULL;
1988
1989         mutex_lock(&mgr->lock);
1990         if (mgr->mst_primary) {
1991                 rport = drm_dp_mst_topology_get_port_validated_locked(
1992                     mgr->mst_primary, port);
1993
1994                 if (rport && !drm_dp_mst_topology_try_get_port(rport))
1995                         rport = NULL;
1996         }
1997         mutex_unlock(&mgr->lock);
1998         return rport;
1999 }
2000
2001 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2002 {
2003         struct drm_dp_mst_port *port;
2004         int ret;
2005
2006         list_for_each_entry(port, &mstb->ports, next) {
2007                 if (port->port_num == port_num) {
2008                         ret = drm_dp_mst_topology_try_get_port(port);
2009                         return ret ? port : NULL;
2010                 }
2011         }
2012
2013         return NULL;
2014 }
2015
2016 /*
2017  * calculate a new RAD for this MST branch device
2018  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2019  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2020  */
2021 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2022                                  u8 *rad)
2023 {
2024         int parent_lct = port->parent->lct;
2025         int shift = 4;
2026         int idx = (parent_lct - 1) / 2;
2027
2028         if (parent_lct > 1) {
2029                 memcpy(rad, port->parent->rad, idx + 1);
2030                 shift = (parent_lct % 2) ? 4 : 0;
2031         } else
2032                 rad[0] = 0;
2033
2034         rad[idx] |= port->port_num << shift;
2035         return parent_lct + 1;
2036 }
2037
2038 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2039 {
2040         switch (pdt) {
2041         case DP_PEER_DEVICE_DP_LEGACY_CONV:
2042         case DP_PEER_DEVICE_SST_SINK:
2043                 return true;
2044         case DP_PEER_DEVICE_MST_BRANCHING:
2045                 /* For sst branch device */
2046                 if (!mcs)
2047                         return true;
2048
2049                 return false;
2050         }
2051         return true;
2052 }
2053
2054 static int
2055 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2056                     bool new_mcs)
2057 {
2058         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2059         struct drm_dp_mst_branch *mstb;
2060         u8 rad[8], lct;
2061         int ret = 0;
2062
2063         if (port->pdt == new_pdt && port->mcs == new_mcs)
2064                 return 0;
2065
2066         /* Teardown the old pdt, if there is one */
2067         if (port->pdt != DP_PEER_DEVICE_NONE) {
2068                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2069                         /*
2070                          * If the new PDT would also have an i2c bus,
2071                          * don't bother with reregistering it
2072                          */
2073                         if (new_pdt != DP_PEER_DEVICE_NONE &&
2074                             drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2075                                 port->pdt = new_pdt;
2076                                 port->mcs = new_mcs;
2077                                 return 0;
2078                         }
2079
2080                         /* remove i2c over sideband */
2081                         drm_dp_mst_unregister_i2c_bus(port);
2082                 } else {
2083                         mutex_lock(&mgr->lock);
2084                         drm_dp_mst_topology_put_mstb(port->mstb);
2085                         port->mstb = NULL;
2086                         mutex_unlock(&mgr->lock);
2087                 }
2088         }
2089
2090         port->pdt = new_pdt;
2091         port->mcs = new_mcs;
2092
2093         if (port->pdt != DP_PEER_DEVICE_NONE) {
2094                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2095                         /* add i2c over sideband */
2096                         ret = drm_dp_mst_register_i2c_bus(port);
2097                 } else {
2098                         lct = drm_dp_calculate_rad(port, rad);
2099                         mstb = drm_dp_add_mst_branch_device(lct, rad);
2100                         if (!mstb) {
2101                                 ret = -ENOMEM;
2102                                 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2103                                 goto out;
2104                         }
2105
2106                         mutex_lock(&mgr->lock);
2107                         port->mstb = mstb;
2108                         mstb->mgr = port->mgr;
2109                         mstb->port_parent = port;
2110
2111                         /*
2112                          * Make sure this port's memory allocation stays
2113                          * around until its child MSTB releases it
2114                          */
2115                         drm_dp_mst_get_port_malloc(port);
2116                         mutex_unlock(&mgr->lock);
2117
2118                         /* And make sure we send a link address for this */
2119                         ret = 1;
2120                 }
2121         }
2122
2123 out:
2124         if (ret < 0)
2125                 port->pdt = DP_PEER_DEVICE_NONE;
2126         return ret;
2127 }
2128
2129 /**
2130  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2131  * @aux: Fake sideband AUX CH
2132  * @offset: address of the (first) register to read
2133  * @buffer: buffer to store the register values
2134  * @size: number of bytes in @buffer
2135  *
2136  * Performs the same functionality for remote devices via
2137  * sideband messaging as drm_dp_dpcd_read() does for local
2138  * devices via actual AUX CH.
2139  *
2140  * Return: Number of bytes read, or negative error code on failure.
2141  */
2142 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2143                              unsigned int offset, void *buffer, size_t size)
2144 {
2145         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2146                                                     aux);
2147
2148         return drm_dp_send_dpcd_read(port->mgr, port,
2149                                      offset, size, buffer);
2150 }
2151
2152 /**
2153  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2154  * @aux: Fake sideband AUX CH
2155  * @offset: address of the (first) register to write
2156  * @buffer: buffer containing the values to write
2157  * @size: number of bytes in @buffer
2158  *
2159  * Performs the same functionality for remote devices via
2160  * sideband messaging as drm_dp_dpcd_write() does for local
2161  * devices via actual AUX CH.
2162  *
2163  * Return: number of bytes written on success, negative error code on failure.
2164  */
2165 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2166                               unsigned int offset, void *buffer, size_t size)
2167 {
2168         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2169                                                     aux);
2170
2171         return drm_dp_send_dpcd_write(port->mgr, port,
2172                                       offset, size, buffer);
2173 }
2174
2175 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2176 {
2177         int ret = 0;
2178
2179         memcpy(mstb->guid, guid, 16);
2180
2181         if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2182                 if (mstb->port_parent) {
2183                         ret = drm_dp_send_dpcd_write(mstb->mgr,
2184                                                      mstb->port_parent,
2185                                                      DP_GUID, 16, mstb->guid);
2186                 } else {
2187                         ret = drm_dp_dpcd_write(mstb->mgr->aux,
2188                                                 DP_GUID, mstb->guid, 16);
2189                 }
2190         }
2191
2192         if (ret < 16 && ret > 0)
2193                 return -EPROTO;
2194
2195         return ret == 16 ? 0 : ret;
2196 }
2197
2198 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2199                                 int pnum,
2200                                 char *proppath,
2201                                 size_t proppath_size)
2202 {
2203         int i;
2204         char temp[8];
2205
2206         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2207         for (i = 0; i < (mstb->lct - 1); i++) {
2208                 int shift = (i % 2) ? 0 : 4;
2209                 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2210
2211                 snprintf(temp, sizeof(temp), "-%d", port_num);
2212                 strlcat(proppath, temp, proppath_size);
2213         }
2214         snprintf(temp, sizeof(temp), "-%d", pnum);
2215         strlcat(proppath, temp, proppath_size);
2216 }
2217
2218 /**
2219  * drm_dp_mst_connector_late_register() - Late MST connector registration
2220  * @connector: The MST connector
2221  * @port: The MST port for this connector
2222  *
2223  * Helper to register the remote aux device for this MST port. Drivers should
2224  * call this from their mst connector's late_register hook to enable MST aux
2225  * devices.
2226  *
2227  * Return: 0 on success, negative error code on failure.
2228  */
2229 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2230                                        struct drm_dp_mst_port *port)
2231 {
2232         drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2233                     port->aux.name, connector->kdev->kobj.name);
2234
2235         port->aux.dev = connector->kdev;
2236         return drm_dp_aux_register_devnode(&port->aux);
2237 }
2238 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2239
2240 /**
2241  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2242  * @connector: The MST connector
2243  * @port: The MST port for this connector
2244  *
2245  * Helper to unregister the remote aux device for this MST port, registered by
2246  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2247  * connector's early_unregister hook.
2248  */
2249 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2250                                            struct drm_dp_mst_port *port)
2251 {
2252         drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2253                     port->aux.name, connector->kdev->kobj.name);
2254         drm_dp_aux_unregister_devnode(&port->aux);
2255 }
2256 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2257
2258 static void
2259 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2260                               struct drm_dp_mst_port *port)
2261 {
2262         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2263         char proppath[255];
2264         int ret;
2265
2266         build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2267         port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2268         if (!port->connector) {
2269                 ret = -ENOMEM;
2270                 goto error;
2271         }
2272
2273         if (port->pdt != DP_PEER_DEVICE_NONE &&
2274             drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2275             port->port_num >= DP_MST_LOGICAL_PORT_0)
2276                 port->cached_edid = drm_edid_read_ddc(port->connector,
2277                                                       &port->aux.ddc);
2278
2279         drm_connector_register(port->connector);
2280         return;
2281
2282 error:
2283         drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2284 }
2285
2286 /*
2287  * Drop a topology reference, and unlink the port from the in-memory topology
2288  * layout
2289  */
2290 static void
2291 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2292                                 struct drm_dp_mst_port *port)
2293 {
2294         mutex_lock(&mgr->lock);
2295         port->parent->num_ports--;
2296         list_del(&port->next);
2297         mutex_unlock(&mgr->lock);
2298         drm_dp_mst_topology_put_port(port);
2299 }
2300
2301 static struct drm_dp_mst_port *
2302 drm_dp_mst_add_port(struct drm_device *dev,
2303                     struct drm_dp_mst_topology_mgr *mgr,
2304                     struct drm_dp_mst_branch *mstb, u8 port_number)
2305 {
2306         struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2307
2308         if (!port)
2309                 return NULL;
2310
2311         kref_init(&port->topology_kref);
2312         kref_init(&port->malloc_kref);
2313         port->parent = mstb;
2314         port->port_num = port_number;
2315         port->mgr = mgr;
2316         port->aux.name = "DPMST";
2317         port->aux.dev = dev->dev;
2318         port->aux.is_remote = true;
2319
2320         /* initialize the MST downstream port's AUX crc work queue */
2321         port->aux.drm_dev = dev;
2322         drm_dp_remote_aux_init(&port->aux);
2323
2324         /*
2325          * Make sure the memory allocation for our parent branch stays
2326          * around until our own memory allocation is released
2327          */
2328         drm_dp_mst_get_mstb_malloc(mstb);
2329
2330         return port;
2331 }
2332
2333 static int
2334 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2335                                     struct drm_device *dev,
2336                                     struct drm_dp_link_addr_reply_port *port_msg)
2337 {
2338         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2339         struct drm_dp_mst_port *port;
2340         int old_ddps = 0, ret;
2341         u8 new_pdt = DP_PEER_DEVICE_NONE;
2342         bool new_mcs = 0;
2343         bool created = false, send_link_addr = false, changed = false;
2344
2345         port = drm_dp_get_port(mstb, port_msg->port_number);
2346         if (!port) {
2347                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2348                                            port_msg->port_number);
2349                 if (!port)
2350                         return -ENOMEM;
2351                 created = true;
2352                 changed = true;
2353         } else if (!port->input && port_msg->input_port && port->connector) {
2354                 /* Since port->connector can't be changed here, we create a
2355                  * new port if input_port changes from 0 to 1
2356                  */
2357                 drm_dp_mst_topology_unlink_port(mgr, port);
2358                 drm_dp_mst_topology_put_port(port);
2359                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2360                                            port_msg->port_number);
2361                 if (!port)
2362                         return -ENOMEM;
2363                 changed = true;
2364                 created = true;
2365         } else if (port->input && !port_msg->input_port) {
2366                 changed = true;
2367         } else if (port->connector) {
2368                 /* We're updating a port that's exposed to userspace, so do it
2369                  * under lock
2370                  */
2371                 drm_modeset_lock(&mgr->base.lock, NULL);
2372
2373                 old_ddps = port->ddps;
2374                 changed = port->ddps != port_msg->ddps ||
2375                         (port->ddps &&
2376                          (port->ldps != port_msg->legacy_device_plug_status ||
2377                           port->dpcd_rev != port_msg->dpcd_revision ||
2378                           port->mcs != port_msg->mcs ||
2379                           port->pdt != port_msg->peer_device_type ||
2380                           port->num_sdp_stream_sinks !=
2381                           port_msg->num_sdp_stream_sinks));
2382         }
2383
2384         port->input = port_msg->input_port;
2385         if (!port->input)
2386                 new_pdt = port_msg->peer_device_type;
2387         new_mcs = port_msg->mcs;
2388         port->ddps = port_msg->ddps;
2389         port->ldps = port_msg->legacy_device_plug_status;
2390         port->dpcd_rev = port_msg->dpcd_revision;
2391         port->num_sdp_streams = port_msg->num_sdp_streams;
2392         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2393
2394         /* manage mstb port lists with mgr lock - take a reference
2395            for this list */
2396         if (created) {
2397                 mutex_lock(&mgr->lock);
2398                 drm_dp_mst_topology_get_port(port);
2399                 list_add(&port->next, &mstb->ports);
2400                 mstb->num_ports++;
2401                 mutex_unlock(&mgr->lock);
2402         }
2403
2404         /*
2405          * Reprobe PBN caps on both hotplug, and when re-probing the link
2406          * for our parent mstb
2407          */
2408         if (old_ddps != port->ddps || !created) {
2409                 if (port->ddps && !port->input) {
2410                         ret = drm_dp_send_enum_path_resources(mgr, mstb,
2411                                                               port);
2412                         if (ret == 1)
2413                                 changed = true;
2414                 } else {
2415                         port->full_pbn = 0;
2416                 }
2417         }
2418
2419         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2420         if (ret == 1) {
2421                 send_link_addr = true;
2422         } else if (ret < 0) {
2423                 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2424                 goto fail;
2425         }
2426
2427         /*
2428          * If this port wasn't just created, then we're reprobing because
2429          * we're coming out of suspend. In this case, always resend the link
2430          * address if there's an MSTB on this port
2431          */
2432         if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2433             port->mcs)
2434                 send_link_addr = true;
2435
2436         if (port->connector)
2437                 drm_modeset_unlock(&mgr->base.lock);
2438         else if (!port->input)
2439                 drm_dp_mst_port_add_connector(mstb, port);
2440
2441         if (send_link_addr && port->mstb) {
2442                 ret = drm_dp_send_link_address(mgr, port->mstb);
2443                 if (ret == 1) /* MSTB below us changed */
2444                         changed = true;
2445                 else if (ret < 0)
2446                         goto fail_put;
2447         }
2448
2449         /* put reference to this port */
2450         drm_dp_mst_topology_put_port(port);
2451         return changed;
2452
2453 fail:
2454         drm_dp_mst_topology_unlink_port(mgr, port);
2455         if (port->connector)
2456                 drm_modeset_unlock(&mgr->base.lock);
2457 fail_put:
2458         drm_dp_mst_topology_put_port(port);
2459         return ret;
2460 }
2461
2462 static int
2463 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2464                             struct drm_dp_connection_status_notify *conn_stat)
2465 {
2466         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2467         struct drm_dp_mst_port *port;
2468         int old_ddps, ret;
2469         u8 new_pdt;
2470         bool new_mcs;
2471         bool dowork = false, create_connector = false;
2472
2473         port = drm_dp_get_port(mstb, conn_stat->port_number);
2474         if (!port)
2475                 return 0;
2476
2477         if (port->connector) {
2478                 if (!port->input && conn_stat->input_port) {
2479                         /*
2480                          * We can't remove a connector from an already exposed
2481                          * port, so just throw the port out and make sure we
2482                          * reprobe the link address of it's parent MSTB
2483                          */
2484                         drm_dp_mst_topology_unlink_port(mgr, port);
2485                         mstb->link_address_sent = false;
2486                         dowork = true;
2487                         goto out;
2488                 }
2489
2490                 /* Locking is only needed if the port's exposed to userspace */
2491                 drm_modeset_lock(&mgr->base.lock, NULL);
2492         } else if (port->input && !conn_stat->input_port) {
2493                 create_connector = true;
2494                 /* Reprobe link address so we get num_sdp_streams */
2495                 mstb->link_address_sent = false;
2496                 dowork = true;
2497         }
2498
2499         old_ddps = port->ddps;
2500         port->input = conn_stat->input_port;
2501         port->ldps = conn_stat->legacy_device_plug_status;
2502         port->ddps = conn_stat->displayport_device_plug_status;
2503
2504         if (old_ddps != port->ddps) {
2505                 if (port->ddps && !port->input)
2506                         drm_dp_send_enum_path_resources(mgr, mstb, port);
2507                 else
2508                         port->full_pbn = 0;
2509         }
2510
2511         new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2512         new_mcs = conn_stat->message_capability_status;
2513         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2514         if (ret == 1) {
2515                 dowork = true;
2516         } else if (ret < 0) {
2517                 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2518                 dowork = false;
2519         }
2520
2521         if (port->connector)
2522                 drm_modeset_unlock(&mgr->base.lock);
2523         else if (create_connector)
2524                 drm_dp_mst_port_add_connector(mstb, port);
2525
2526 out:
2527         drm_dp_mst_topology_put_port(port);
2528         return dowork;
2529 }
2530
2531 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2532                                                                u8 lct, u8 *rad)
2533 {
2534         struct drm_dp_mst_branch *mstb;
2535         struct drm_dp_mst_port *port;
2536         int i, ret;
2537         /* find the port by iterating down */
2538
2539         mutex_lock(&mgr->lock);
2540         mstb = mgr->mst_primary;
2541
2542         if (!mstb)
2543                 goto out;
2544
2545         for (i = 0; i < lct - 1; i++) {
2546                 int shift = (i % 2) ? 0 : 4;
2547                 int port_num = (rad[i / 2] >> shift) & 0xf;
2548
2549                 list_for_each_entry(port, &mstb->ports, next) {
2550                         if (port->port_num == port_num) {
2551                                 mstb = port->mstb;
2552                                 if (!mstb) {
2553                                         drm_err(mgr->dev,
2554                                                 "failed to lookup MSTB with lct %d, rad %02x\n",
2555                                                 lct, rad[0]);
2556                                         goto out;
2557                                 }
2558
2559                                 break;
2560                         }
2561                 }
2562         }
2563         ret = drm_dp_mst_topology_try_get_mstb(mstb);
2564         if (!ret)
2565                 mstb = NULL;
2566 out:
2567         mutex_unlock(&mgr->lock);
2568         return mstb;
2569 }
2570
2571 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2572         struct drm_dp_mst_branch *mstb,
2573         const uint8_t *guid)
2574 {
2575         struct drm_dp_mst_branch *found_mstb;
2576         struct drm_dp_mst_port *port;
2577
2578         if (!mstb)
2579                 return NULL;
2580
2581         if (memcmp(mstb->guid, guid, 16) == 0)
2582                 return mstb;
2583
2584
2585         list_for_each_entry(port, &mstb->ports, next) {
2586                 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2587
2588                 if (found_mstb)
2589                         return found_mstb;
2590         }
2591
2592         return NULL;
2593 }
2594
2595 static struct drm_dp_mst_branch *
2596 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2597                                      const uint8_t *guid)
2598 {
2599         struct drm_dp_mst_branch *mstb;
2600         int ret;
2601
2602         /* find the port by iterating down */
2603         mutex_lock(&mgr->lock);
2604
2605         mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2606         if (mstb) {
2607                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2608                 if (!ret)
2609                         mstb = NULL;
2610         }
2611
2612         mutex_unlock(&mgr->lock);
2613         return mstb;
2614 }
2615
2616 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2617                                                struct drm_dp_mst_branch *mstb)
2618 {
2619         struct drm_dp_mst_port *port;
2620         int ret;
2621         bool changed = false;
2622
2623         if (!mstb->link_address_sent) {
2624                 ret = drm_dp_send_link_address(mgr, mstb);
2625                 if (ret == 1)
2626                         changed = true;
2627                 else if (ret < 0)
2628                         return ret;
2629         }
2630
2631         list_for_each_entry(port, &mstb->ports, next) {
2632                 if (port->input || !port->ddps || !port->mstb)
2633                         continue;
2634
2635                 ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
2636                 if (ret == 1)
2637                         changed = true;
2638                 else if (ret < 0)
2639                         return ret;
2640         }
2641
2642         return changed;
2643 }
2644
2645 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2646 {
2647         struct drm_dp_mst_topology_mgr *mgr =
2648                 container_of(work, struct drm_dp_mst_topology_mgr, work);
2649         struct drm_device *dev = mgr->dev;
2650         struct drm_dp_mst_branch *mstb;
2651         int ret;
2652         bool clear_payload_id_table;
2653
2654         mutex_lock(&mgr->probe_lock);
2655
2656         mutex_lock(&mgr->lock);
2657         clear_payload_id_table = !mgr->payload_id_table_cleared;
2658         mgr->payload_id_table_cleared = true;
2659
2660         mstb = mgr->mst_primary;
2661         if (mstb) {
2662                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2663                 if (!ret)
2664                         mstb = NULL;
2665         }
2666         mutex_unlock(&mgr->lock);
2667         if (!mstb) {
2668                 mutex_unlock(&mgr->probe_lock);
2669                 return;
2670         }
2671
2672         /*
2673          * Certain branch devices seem to incorrectly report an available_pbn
2674          * of 0 on downstream sinks, even after clearing the
2675          * DP_PAYLOAD_ALLOCATE_* registers in
2676          * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2677          * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2678          * things work again.
2679          */
2680         if (clear_payload_id_table) {
2681                 drm_dbg_kms(dev, "Clearing payload ID table\n");
2682                 drm_dp_send_clear_payload_id_table(mgr, mstb);
2683         }
2684
2685         ret = drm_dp_check_and_send_link_address(mgr, mstb);
2686         drm_dp_mst_topology_put_mstb(mstb);
2687
2688         mutex_unlock(&mgr->probe_lock);
2689         if (ret > 0)
2690                 drm_kms_helper_hotplug_event(dev);
2691 }
2692
2693 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2694                                  u8 *guid)
2695 {
2696         u64 salt;
2697
2698         if (memchr_inv(guid, 0, 16))
2699                 return true;
2700
2701         salt = get_jiffies_64();
2702
2703         memcpy(&guid[0], &salt, sizeof(u64));
2704         memcpy(&guid[8], &salt, sizeof(u64));
2705
2706         return false;
2707 }
2708
2709 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2710                             u8 port_num, u32 offset, u8 num_bytes)
2711 {
2712         struct drm_dp_sideband_msg_req_body req;
2713
2714         req.req_type = DP_REMOTE_DPCD_READ;
2715         req.u.dpcd_read.port_number = port_num;
2716         req.u.dpcd_read.dpcd_address = offset;
2717         req.u.dpcd_read.num_bytes = num_bytes;
2718         drm_dp_encode_sideband_req(&req, msg);
2719 }
2720
2721 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2722                                     bool up, u8 *msg, int len)
2723 {
2724         int ret;
2725         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2726         int tosend, total, offset;
2727         int retries = 0;
2728
2729 retry:
2730         total = len;
2731         offset = 0;
2732         do {
2733                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2734
2735                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2736                                         &msg[offset],
2737                                         tosend);
2738                 if (ret != tosend) {
2739                         if (ret == -EIO && retries < 5) {
2740                                 retries++;
2741                                 goto retry;
2742                         }
2743                         drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2744
2745                         return -EIO;
2746                 }
2747                 offset += tosend;
2748                 total -= tosend;
2749         } while (total > 0);
2750         return 0;
2751 }
2752
2753 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2754                                   struct drm_dp_sideband_msg_tx *txmsg)
2755 {
2756         struct drm_dp_mst_branch *mstb = txmsg->dst;
2757         u8 req_type;
2758
2759         req_type = txmsg->msg[0] & 0x7f;
2760         if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2761                 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2762                 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2763                 hdr->broadcast = 1;
2764         else
2765                 hdr->broadcast = 0;
2766         hdr->path_msg = txmsg->path_msg;
2767         if (hdr->broadcast) {
2768                 hdr->lct = 1;
2769                 hdr->lcr = 6;
2770         } else {
2771                 hdr->lct = mstb->lct;
2772                 hdr->lcr = mstb->lct - 1;
2773         }
2774
2775         memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2776
2777         return 0;
2778 }
2779 /*
2780  * process a single block of the next message in the sideband queue
2781  */
2782 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2783                                    struct drm_dp_sideband_msg_tx *txmsg,
2784                                    bool up)
2785 {
2786         u8 chunk[48];
2787         struct drm_dp_sideband_msg_hdr hdr;
2788         int len, space, idx, tosend;
2789         int ret;
2790
2791         if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2792                 return 0;
2793
2794         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2795
2796         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2797                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2798
2799         /* make hdr from dst mst */
2800         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2801         if (ret < 0)
2802                 return ret;
2803
2804         /* amount left to send in this message */
2805         len = txmsg->cur_len - txmsg->cur_offset;
2806
2807         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2808         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2809
2810         tosend = min(len, space);
2811         if (len == txmsg->cur_len)
2812                 hdr.somt = 1;
2813         if (space >= len)
2814                 hdr.eomt = 1;
2815
2816
2817         hdr.msg_len = tosend + 1;
2818         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2819         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2820         /* add crc at end */
2821         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2822         idx += tosend + 1;
2823
2824         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2825         if (ret) {
2826                 if (drm_debug_enabled(DRM_UT_DP)) {
2827                         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2828
2829                         drm_printf(&p, "sideband msg failed to send\n");
2830                         drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2831                 }
2832                 return ret;
2833         }
2834
2835         txmsg->cur_offset += tosend;
2836         if (txmsg->cur_offset == txmsg->cur_len) {
2837                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2838                 return 1;
2839         }
2840         return 0;
2841 }
2842
2843 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2844 {
2845         struct drm_dp_sideband_msg_tx *txmsg;
2846         int ret;
2847
2848         WARN_ON(!mutex_is_locked(&mgr->qlock));
2849
2850         /* construct a chunk from the first msg in the tx_msg queue */
2851         if (list_empty(&mgr->tx_msg_downq))
2852                 return;
2853
2854         txmsg = list_first_entry(&mgr->tx_msg_downq,
2855                                  struct drm_dp_sideband_msg_tx, next);
2856         ret = process_single_tx_qlock(mgr, txmsg, false);
2857         if (ret < 0) {
2858                 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2859                 list_del(&txmsg->next);
2860                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2861                 wake_up_all(&mgr->tx_waitq);
2862         }
2863 }
2864
2865 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2866                                  struct drm_dp_sideband_msg_tx *txmsg)
2867 {
2868         mutex_lock(&mgr->qlock);
2869         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2870
2871         if (drm_debug_enabled(DRM_UT_DP)) {
2872                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2873
2874                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2875         }
2876
2877         if (list_is_singular(&mgr->tx_msg_downq))
2878                 process_single_down_tx_qlock(mgr);
2879         mutex_unlock(&mgr->qlock);
2880 }
2881
2882 static void
2883 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2884                          struct drm_dp_link_address_ack_reply *reply)
2885 {
2886         struct drm_dp_link_addr_reply_port *port_reply;
2887         int i;
2888
2889         for (i = 0; i < reply->nports; i++) {
2890                 port_reply = &reply->ports[i];
2891                 drm_dbg_kms(mgr->dev,
2892                             "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2893                             i,
2894                             port_reply->input_port,
2895                             port_reply->peer_device_type,
2896                             port_reply->port_number,
2897                             port_reply->dpcd_revision,
2898                             port_reply->mcs,
2899                             port_reply->ddps,
2900                             port_reply->legacy_device_plug_status,
2901                             port_reply->num_sdp_streams,
2902                             port_reply->num_sdp_stream_sinks);
2903         }
2904 }
2905
2906 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2907                                      struct drm_dp_mst_branch *mstb)
2908 {
2909         struct drm_dp_sideband_msg_tx *txmsg;
2910         struct drm_dp_link_address_ack_reply *reply;
2911         struct drm_dp_mst_port *port, *tmp;
2912         int i, ret, port_mask = 0;
2913         bool changed = false;
2914
2915         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2916         if (!txmsg)
2917                 return -ENOMEM;
2918
2919         txmsg->dst = mstb;
2920         build_link_address(txmsg);
2921
2922         mstb->link_address_sent = true;
2923         drm_dp_queue_down_tx(mgr, txmsg);
2924
2925         /* FIXME: Actually do some real error handling here */
2926         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2927         if (ret <= 0) {
2928                 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2929                 goto out;
2930         }
2931         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2932                 drm_err(mgr->dev, "link address NAK received\n");
2933                 ret = -EIO;
2934                 goto out;
2935         }
2936
2937         reply = &txmsg->reply.u.link_addr;
2938         drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2939         drm_dp_dump_link_address(mgr, reply);
2940
2941         ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2942         if (ret) {
2943                 char buf[64];
2944
2945                 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2946                 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2947                 goto out;
2948         }
2949
2950         for (i = 0; i < reply->nports; i++) {
2951                 port_mask |= BIT(reply->ports[i].port_number);
2952                 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2953                                                           &reply->ports[i]);
2954                 if (ret == 1)
2955                         changed = true;
2956                 else if (ret < 0)
2957                         goto out;
2958         }
2959
2960         /* Prune any ports that are currently a part of mstb in our in-memory
2961          * topology, but were not seen in this link address. Usually this
2962          * means that they were removed while the topology was out of sync,
2963          * e.g. during suspend/resume
2964          */
2965         mutex_lock(&mgr->lock);
2966         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2967                 if (port_mask & BIT(port->port_num))
2968                         continue;
2969
2970                 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
2971                             port->port_num);
2972                 list_del(&port->next);
2973                 drm_dp_mst_topology_put_port(port);
2974                 changed = true;
2975         }
2976         mutex_unlock(&mgr->lock);
2977
2978 out:
2979         if (ret <= 0)
2980                 mstb->link_address_sent = false;
2981         kfree(txmsg);
2982         return ret < 0 ? ret : changed;
2983 }
2984
2985 static void
2986 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
2987                                    struct drm_dp_mst_branch *mstb)
2988 {
2989         struct drm_dp_sideband_msg_tx *txmsg;
2990         int ret;
2991
2992         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2993         if (!txmsg)
2994                 return;
2995
2996         txmsg->dst = mstb;
2997         build_clear_payload_id_table(txmsg);
2998
2999         drm_dp_queue_down_tx(mgr, txmsg);
3000
3001         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3002         if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3003                 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3004
3005         kfree(txmsg);
3006 }
3007
3008 static int
3009 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3010                                 struct drm_dp_mst_branch *mstb,
3011                                 struct drm_dp_mst_port *port)
3012 {
3013         struct drm_dp_enum_path_resources_ack_reply *path_res;
3014         struct drm_dp_sideband_msg_tx *txmsg;
3015         int ret;
3016
3017         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3018         if (!txmsg)
3019                 return -ENOMEM;
3020
3021         txmsg->dst = mstb;
3022         build_enum_path_resources(txmsg, port->port_num);
3023
3024         drm_dp_queue_down_tx(mgr, txmsg);
3025
3026         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3027         if (ret > 0) {
3028                 ret = 0;
3029                 path_res = &txmsg->reply.u.path_resources;
3030
3031                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3032                         drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3033                 } else {
3034                         if (port->port_num != path_res->port_number)
3035                                 DRM_ERROR("got incorrect port in response\n");
3036
3037                         drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3038                                     path_res->port_number,
3039                                     path_res->full_payload_bw_number,
3040                                     path_res->avail_payload_bw_number);
3041
3042                         /*
3043                          * If something changed, make sure we send a
3044                          * hotplug
3045                          */
3046                         if (port->full_pbn != path_res->full_payload_bw_number ||
3047                             port->fec_capable != path_res->fec_capable)
3048                                 ret = 1;
3049
3050                         port->full_pbn = path_res->full_payload_bw_number;
3051                         port->fec_capable = path_res->fec_capable;
3052                 }
3053         }
3054
3055         kfree(txmsg);
3056         return ret;
3057 }
3058
3059 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3060 {
3061         if (!mstb->port_parent)
3062                 return NULL;
3063
3064         if (mstb->port_parent->mstb != mstb)
3065                 return mstb->port_parent;
3066
3067         return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3068 }
3069
3070 /*
3071  * Searches upwards in the topology starting from mstb to try to find the
3072  * closest available parent of mstb that's still connected to the rest of the
3073  * topology. This can be used in order to perform operations like releasing
3074  * payloads, where the branch device which owned the payload may no longer be
3075  * around and thus would require that the payload on the last living relative
3076  * be freed instead.
3077  */
3078 static struct drm_dp_mst_branch *
3079 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3080                                         struct drm_dp_mst_branch *mstb,
3081                                         int *port_num)
3082 {
3083         struct drm_dp_mst_branch *rmstb = NULL;
3084         struct drm_dp_mst_port *found_port;
3085
3086         mutex_lock(&mgr->lock);
3087         if (!mgr->mst_primary)
3088                 goto out;
3089
3090         do {
3091                 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3092                 if (!found_port)
3093                         break;
3094
3095                 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3096                         rmstb = found_port->parent;
3097                         *port_num = found_port->port_num;
3098                 } else {
3099                         /* Search again, starting from this parent */
3100                         mstb = found_port->parent;
3101                 }
3102         } while (!rmstb);
3103 out:
3104         mutex_unlock(&mgr->lock);
3105         return rmstb;
3106 }
3107
3108 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3109                                    struct drm_dp_mst_port *port,
3110                                    int id,
3111                                    int pbn)
3112 {
3113         struct drm_dp_sideband_msg_tx *txmsg;
3114         struct drm_dp_mst_branch *mstb;
3115         int ret, port_num;
3116         u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3117         int i;
3118
3119         port_num = port->port_num;
3120         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3121         if (!mstb) {
3122                 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3123                                                                port->parent,
3124                                                                &port_num);
3125
3126                 if (!mstb)
3127                         return -EINVAL;
3128         }
3129
3130         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3131         if (!txmsg) {
3132                 ret = -ENOMEM;
3133                 goto fail_put;
3134         }
3135
3136         for (i = 0; i < port->num_sdp_streams; i++)
3137                 sinks[i] = i;
3138
3139         txmsg->dst = mstb;
3140         build_allocate_payload(txmsg, port_num,
3141                                id,
3142                                pbn, port->num_sdp_streams, sinks);
3143
3144         drm_dp_queue_down_tx(mgr, txmsg);
3145
3146         /*
3147          * FIXME: there is a small chance that between getting the last
3148          * connected mstb and sending the payload message, the last connected
3149          * mstb could also be removed from the topology. In the future, this
3150          * needs to be fixed by restarting the
3151          * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3152          * timeout if the topology is still connected to the system.
3153          */
3154         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3155         if (ret > 0) {
3156                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3157                         ret = -EINVAL;
3158                 else
3159                         ret = 0;
3160         }
3161         kfree(txmsg);
3162 fail_put:
3163         drm_dp_mst_topology_put_mstb(mstb);
3164         return ret;
3165 }
3166
3167 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3168                                  struct drm_dp_mst_port *port, bool power_up)
3169 {
3170         struct drm_dp_sideband_msg_tx *txmsg;
3171         int ret;
3172
3173         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3174         if (!port)
3175                 return -EINVAL;
3176
3177         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3178         if (!txmsg) {
3179                 drm_dp_mst_topology_put_port(port);
3180                 return -ENOMEM;
3181         }
3182
3183         txmsg->dst = port->parent;
3184         build_power_updown_phy(txmsg, port->port_num, power_up);
3185         drm_dp_queue_down_tx(mgr, txmsg);
3186
3187         ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3188         if (ret > 0) {
3189                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3190                         ret = -EINVAL;
3191                 else
3192                         ret = 0;
3193         }
3194         kfree(txmsg);
3195         drm_dp_mst_topology_put_port(port);
3196
3197         return ret;
3198 }
3199 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3200
3201 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3202                 struct drm_dp_mst_port *port,
3203                 struct drm_dp_query_stream_enc_status_ack_reply *status)
3204 {
3205         struct drm_dp_mst_topology_state *state;
3206         struct drm_dp_mst_atomic_payload *payload;
3207         struct drm_dp_sideband_msg_tx *txmsg;
3208         u8 nonce[7];
3209         int ret;
3210
3211         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3212         if (!txmsg)
3213                 return -ENOMEM;
3214
3215         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3216         if (!port) {
3217                 ret = -EINVAL;
3218                 goto out_get_port;
3219         }
3220
3221         get_random_bytes(nonce, sizeof(nonce));
3222
3223         drm_modeset_lock(&mgr->base.lock, NULL);
3224         state = to_drm_dp_mst_topology_state(mgr->base.state);
3225         payload = drm_atomic_get_mst_payload_state(state, port);
3226
3227         /*
3228          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3229          *  transaction at the MST Branch device directly connected to the
3230          *  Source"
3231          */
3232         txmsg->dst = mgr->mst_primary;
3233
3234         build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
3235
3236         drm_dp_queue_down_tx(mgr, txmsg);
3237
3238         ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3239         if (ret < 0) {
3240                 goto out;
3241         } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3242                 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3243                 ret = -ENXIO;
3244                 goto out;
3245         }
3246
3247         ret = 0;
3248         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3249
3250 out:
3251         drm_modeset_unlock(&mgr->base.lock);
3252         drm_dp_mst_topology_put_port(port);
3253 out_get_port:
3254         kfree(txmsg);
3255         return ret;
3256 }
3257 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3258
3259 static int drm_dp_create_payload_at_dfp(struct drm_dp_mst_topology_mgr *mgr,
3260                                         struct drm_dp_mst_atomic_payload *payload)
3261 {
3262         return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot,
3263                                          payload->time_slots);
3264 }
3265
3266 static int drm_dp_create_payload_to_remote(struct drm_dp_mst_topology_mgr *mgr,
3267                                            struct drm_dp_mst_atomic_payload *payload)
3268 {
3269         int ret;
3270         struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3271
3272         if (!port)
3273                 return -EIO;
3274
3275         ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn);
3276         drm_dp_mst_topology_put_port(port);
3277         return ret;
3278 }
3279
3280 static void drm_dp_destroy_payload_at_remote_and_dfp(struct drm_dp_mst_topology_mgr *mgr,
3281                                                      struct drm_dp_mst_topology_state *mst_state,
3282                                                      struct drm_dp_mst_atomic_payload *payload)
3283 {
3284         drm_dbg_kms(mgr->dev, "\n");
3285
3286         /* it's okay for these to fail */
3287         if (payload->payload_allocation_status == DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE) {
3288                 drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
3289                 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_DFP;
3290         }
3291
3292         if (payload->payload_allocation_status == DRM_DP_MST_PAYLOAD_ALLOCATION_DFP)
3293                 drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0);
3294 }
3295
3296 /**
3297  * drm_dp_add_payload_part1() - Execute payload update part 1
3298  * @mgr: Manager to use.
3299  * @mst_state: The MST atomic state
3300  * @payload: The payload to write
3301  *
3302  * Determines the starting time slot for the given payload, and programs the VCPI for this payload
3303  * into the DPCD of DPRX. After calling this, the driver should generate ACT and payload packets.
3304  *
3305  * Returns: 0 on success, error code on failure.
3306  */
3307 int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3308                              struct drm_dp_mst_topology_state *mst_state,
3309                              struct drm_dp_mst_atomic_payload *payload)
3310 {
3311         struct drm_dp_mst_port *port;
3312         int ret;
3313
3314         /* Update mst mgr info */
3315         if (mgr->payload_count == 0)
3316                 mgr->next_start_slot = mst_state->start_slot;
3317
3318         payload->vc_start_slot = mgr->next_start_slot;
3319
3320         mgr->payload_count++;
3321         mgr->next_start_slot += payload->time_slots;
3322
3323         payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL;
3324
3325         /* Allocate payload to immediate downstream facing port */
3326         port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3327         if (!port) {
3328                 drm_dbg_kms(mgr->dev,
3329                             "VCPI %d for port %p not in topology, not creating a payload to remote\n",
3330                             payload->vcpi, payload->port);
3331                 return -EIO;
3332         }
3333
3334         ret = drm_dp_create_payload_at_dfp(mgr, payload);
3335         if (ret < 0) {
3336                 drm_dbg_kms(mgr->dev, "Failed to create MST payload for port %p: %d\n",
3337                             payload->port, ret);
3338                 goto put_port;
3339         }
3340
3341         payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_DFP;
3342
3343 put_port:
3344         drm_dp_mst_topology_put_port(port);
3345
3346         return ret;
3347 }
3348 EXPORT_SYMBOL(drm_dp_add_payload_part1);
3349
3350 /**
3351  * drm_dp_remove_payload_part1() - Remove an MST payload along the virtual channel
3352  * @mgr: Manager to use.
3353  * @mst_state: The MST atomic state
3354  * @payload: The payload to remove
3355  *
3356  * Removes a payload along the virtual channel if it was successfully allocated.
3357  * After calling this, the driver should set HW to generate ACT and then switch to new
3358  * payload allocation state.
3359  */
3360 void drm_dp_remove_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3361                                  struct drm_dp_mst_topology_state *mst_state,
3362                                  struct drm_dp_mst_atomic_payload *payload)
3363 {
3364         /* Remove remote payload allocation */
3365         bool send_remove = false;
3366
3367         mutex_lock(&mgr->lock);
3368         send_remove = drm_dp_mst_port_downstream_of_branch(payload->port, mgr->mst_primary);
3369         mutex_unlock(&mgr->lock);
3370
3371         if (send_remove)
3372                 drm_dp_destroy_payload_at_remote_and_dfp(mgr, mst_state, payload);
3373         else
3374                 drm_dbg_kms(mgr->dev, "Payload for VCPI %d not in topology, not sending remove\n",
3375                             payload->vcpi);
3376
3377         payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL;
3378 }
3379 EXPORT_SYMBOL(drm_dp_remove_payload_part1);
3380
3381 /**
3382  * drm_dp_remove_payload_part2() - Remove an MST payload locally
3383  * @mgr: Manager to use.
3384  * @mst_state: The MST atomic state
3385  * @old_payload: The payload with its old state
3386  * @new_payload: The payload with its latest state
3387  *
3388  * Updates the starting time slots of all other payloads which would have been shifted towards
3389  * the start of the payload ID table as a result of removing a payload. Driver should call this
3390  * function whenever it removes a payload in its HW. It's independent to the result of payload
3391  * allocation/deallocation at branch devices along the virtual channel.
3392  */
3393 void drm_dp_remove_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3394                                  struct drm_dp_mst_topology_state *mst_state,
3395                                  const struct drm_dp_mst_atomic_payload *old_payload,
3396                                  struct drm_dp_mst_atomic_payload *new_payload)
3397 {
3398         struct drm_dp_mst_atomic_payload *pos;
3399
3400         /* Remove local payload allocation */
3401         list_for_each_entry(pos, &mst_state->payloads, next) {
3402                 if (pos != new_payload && pos->vc_start_slot > new_payload->vc_start_slot)
3403                         pos->vc_start_slot -= old_payload->time_slots;
3404         }
3405         new_payload->vc_start_slot = -1;
3406
3407         mgr->payload_count--;
3408         mgr->next_start_slot -= old_payload->time_slots;
3409
3410         if (new_payload->delete)
3411                 drm_dp_mst_put_port_malloc(new_payload->port);
3412
3413         new_payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_NONE;
3414 }
3415 EXPORT_SYMBOL(drm_dp_remove_payload_part2);
3416 /**
3417  * drm_dp_add_payload_part2() - Execute payload update part 2
3418  * @mgr: Manager to use.
3419  * @state: The global atomic state
3420  * @payload: The payload to update
3421  *
3422  * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this
3423  * function will send the sideband messages to finish allocating this payload.
3424  *
3425  * Returns: 0 on success, negative error code on failure.
3426  */
3427 int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3428                              struct drm_atomic_state *state,
3429                              struct drm_dp_mst_atomic_payload *payload)
3430 {
3431         int ret = 0;
3432
3433         /* Skip failed payloads */
3434         if (payload->payload_allocation_status != DRM_DP_MST_PAYLOAD_ALLOCATION_DFP) {
3435                 drm_dbg_kms(state->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
3436                             payload->port->connector->name);
3437                 return -EIO;
3438         }
3439
3440         /* Allocate payload to remote end */
3441         ret = drm_dp_create_payload_to_remote(mgr, payload);
3442         if (ret < 0)
3443                 drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n",
3444                         payload->port, ret);
3445         else
3446                 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE;
3447
3448         return ret;
3449 }
3450 EXPORT_SYMBOL(drm_dp_add_payload_part2);
3451
3452 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3453                                  struct drm_dp_mst_port *port,
3454                                  int offset, int size, u8 *bytes)
3455 {
3456         int ret = 0;
3457         struct drm_dp_sideband_msg_tx *txmsg;
3458         struct drm_dp_mst_branch *mstb;
3459
3460         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3461         if (!mstb)
3462                 return -EINVAL;
3463
3464         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3465         if (!txmsg) {
3466                 ret = -ENOMEM;
3467                 goto fail_put;
3468         }
3469
3470         build_dpcd_read(txmsg, port->port_num, offset, size);
3471         txmsg->dst = port->parent;
3472
3473         drm_dp_queue_down_tx(mgr, txmsg);
3474
3475         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3476         if (ret < 0)
3477                 goto fail_free;
3478
3479         if (txmsg->reply.reply_type == 1) {
3480                 drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3481                             mstb, port->port_num, offset, size);
3482                 ret = -EIO;
3483                 goto fail_free;
3484         }
3485
3486         if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3487                 ret = -EPROTO;
3488                 goto fail_free;
3489         }
3490
3491         ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3492                     size);
3493         memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3494
3495 fail_free:
3496         kfree(txmsg);
3497 fail_put:
3498         drm_dp_mst_topology_put_mstb(mstb);
3499
3500         return ret;
3501 }
3502
3503 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3504                                   struct drm_dp_mst_port *port,
3505                                   int offset, int size, u8 *bytes)
3506 {
3507         int ret;
3508         struct drm_dp_sideband_msg_tx *txmsg;
3509         struct drm_dp_mst_branch *mstb;
3510
3511         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3512         if (!mstb)
3513                 return -EINVAL;
3514
3515         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3516         if (!txmsg) {
3517                 ret = -ENOMEM;
3518                 goto fail_put;
3519         }
3520
3521         build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3522         txmsg->dst = mstb;
3523
3524         drm_dp_queue_down_tx(mgr, txmsg);
3525
3526         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3527         if (ret > 0) {
3528                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3529                         ret = -EIO;
3530                 else
3531                         ret = size;
3532         }
3533
3534         kfree(txmsg);
3535 fail_put:
3536         drm_dp_mst_topology_put_mstb(mstb);
3537         return ret;
3538 }
3539
3540 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3541 {
3542         struct drm_dp_sideband_msg_reply_body reply;
3543
3544         reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3545         reply.req_type = req_type;
3546         drm_dp_encode_sideband_reply(&reply, msg);
3547         return 0;
3548 }
3549
3550 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3551                                     struct drm_dp_mst_branch *mstb,
3552                                     int req_type, bool broadcast)
3553 {
3554         struct drm_dp_sideband_msg_tx *txmsg;
3555
3556         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3557         if (!txmsg)
3558                 return -ENOMEM;
3559
3560         txmsg->dst = mstb;
3561         drm_dp_encode_up_ack_reply(txmsg, req_type);
3562
3563         mutex_lock(&mgr->qlock);
3564         /* construct a chunk from the first msg in the tx_msg queue */
3565         process_single_tx_qlock(mgr, txmsg, true);
3566         mutex_unlock(&mgr->qlock);
3567
3568         kfree(txmsg);
3569         return 0;
3570 }
3571
3572 /**
3573  * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3574  * @mgr: The &drm_dp_mst_topology_mgr to use
3575  * @link_rate: link rate in 10kbits/s units
3576  * @link_lane_count: lane count
3577  *
3578  * Calculate the total bandwidth of a MultiStream Transport link. The returned
3579  * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3580  * convert the number of PBNs required for a given stream to the number of
3581  * timeslots this stream requires in each MTP.
3582  *
3583  * Returns the BW / timeslot value in 20.12 fixed point format.
3584  */
3585 fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3586                                     int link_rate, int link_lane_count)
3587 {
3588         int ch_coding_efficiency =
3589                 drm_dp_bw_channel_coding_efficiency(drm_dp_is_uhbr_rate(link_rate));
3590         fixed20_12 ret;
3591
3592         if (link_rate == 0 || link_lane_count == 0)
3593                 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3594                             link_rate, link_lane_count);
3595
3596         /* See DP v2.0 2.6.4.2, 2.7.6.3 VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3597         ret.full = DIV_ROUND_DOWN_ULL(mul_u32_u32(link_rate * link_lane_count,
3598                                                   ch_coding_efficiency),
3599                                       (1000000ULL * 8 * 5400) >> 12);
3600
3601         return ret;
3602 }
3603 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3604
3605 /**
3606  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3607  * @aux: The DP AUX channel to use
3608  * @dpcd: A cached copy of the DPCD capabilities for this sink
3609  *
3610  * Returns: %True if the sink supports MST, %false otherwise
3611  */
3612 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3613                          const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3614 {
3615         u8 mstm_cap;
3616
3617         if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3618                 return false;
3619
3620         if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3621                 return false;
3622
3623         return mstm_cap & DP_MST_CAP;
3624 }
3625 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3626
3627 /**
3628  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3629  * @mgr: manager to set state for
3630  * @mst_state: true to enable MST on this connector - false to disable.
3631  *
3632  * This is called by the driver when it detects an MST capable device plugged
3633  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3634  */
3635 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3636 {
3637         int ret = 0;
3638         struct drm_dp_mst_branch *mstb = NULL;
3639
3640         mutex_lock(&mgr->lock);
3641         if (mst_state == mgr->mst_state)
3642                 goto out_unlock;
3643
3644         mgr->mst_state = mst_state;
3645         /* set the device into MST mode */
3646         if (mst_state) {
3647                 WARN_ON(mgr->mst_primary);
3648
3649                 /* get dpcd info */
3650                 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3651                 if (ret < 0) {
3652                         drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3653                                     mgr->aux->name, ret);
3654                         goto out_unlock;
3655                 }
3656
3657                 /* add initial branch device at LCT 1 */
3658                 mstb = drm_dp_add_mst_branch_device(1, NULL);
3659                 if (mstb == NULL) {
3660                         ret = -ENOMEM;
3661                         goto out_unlock;
3662                 }
3663                 mstb->mgr = mgr;
3664
3665                 /* give this the main reference */
3666                 mgr->mst_primary = mstb;
3667                 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3668
3669                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3670                                          DP_MST_EN |
3671                                          DP_UP_REQ_EN |
3672                                          DP_UPSTREAM_IS_SRC);
3673                 if (ret < 0)
3674                         goto out_unlock;
3675
3676                 /* Write reset payload */
3677                 drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
3678
3679                 queue_work(system_long_wq, &mgr->work);
3680
3681                 ret = 0;
3682         } else {
3683                 /* disable MST on the device */
3684                 mstb = mgr->mst_primary;
3685                 mgr->mst_primary = NULL;
3686                 /* this can fail if the device is gone */
3687                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3688                 ret = 0;
3689                 mgr->payload_id_table_cleared = false;
3690
3691                 memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
3692                 memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
3693         }
3694
3695 out_unlock:
3696         mutex_unlock(&mgr->lock);
3697         if (mstb)
3698                 drm_dp_mst_topology_put_mstb(mstb);
3699         return ret;
3700
3701 }
3702 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3703
3704 static void
3705 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3706 {
3707         struct drm_dp_mst_port *port;
3708
3709         /* The link address will need to be re-sent on resume */
3710         mstb->link_address_sent = false;
3711
3712         list_for_each_entry(port, &mstb->ports, next)
3713                 if (port->mstb)
3714                         drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3715 }
3716
3717 /**
3718  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3719  * @mgr: manager to suspend
3720  *
3721  * This function tells the MST device that we can't handle UP messages
3722  * anymore. This should stop it from sending any since we are suspended.
3723  */
3724 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3725 {
3726         mutex_lock(&mgr->lock);
3727         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3728                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
3729         mutex_unlock(&mgr->lock);
3730         flush_work(&mgr->up_req_work);
3731         flush_work(&mgr->work);
3732         flush_work(&mgr->delayed_destroy_work);
3733
3734         mutex_lock(&mgr->lock);
3735         if (mgr->mst_state && mgr->mst_primary)
3736                 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3737         mutex_unlock(&mgr->lock);
3738 }
3739 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3740
3741 /**
3742  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3743  * @mgr: manager to resume
3744  * @sync: whether or not to perform topology reprobing synchronously
3745  *
3746  * This will fetch DPCD and see if the device is still there,
3747  * if it is, it will rewrite the MSTM control bits, and return.
3748  *
3749  * If the device fails this returns -1, and the driver should do
3750  * a full MST reprobe, in case we were undocked.
3751  *
3752  * During system resume (where it is assumed that the driver will be calling
3753  * drm_atomic_helper_resume()) this function should be called beforehand with
3754  * @sync set to true. In contexts like runtime resume where the driver is not
3755  * expected to be calling drm_atomic_helper_resume(), this function should be
3756  * called with @sync set to false in order to avoid deadlocking.
3757  *
3758  * Returns: -1 if the MST topology was removed while we were suspended, 0
3759  * otherwise.
3760  */
3761 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3762                                    bool sync)
3763 {
3764         int ret;
3765         u8 guid[16];
3766
3767         mutex_lock(&mgr->lock);
3768         if (!mgr->mst_primary)
3769                 goto out_fail;
3770
3771         if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3772                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3773                 goto out_fail;
3774         }
3775
3776         ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3777                                  DP_MST_EN |
3778                                  DP_UP_REQ_EN |
3779                                  DP_UPSTREAM_IS_SRC);
3780         if (ret < 0) {
3781                 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3782                 goto out_fail;
3783         }
3784
3785         /* Some hubs forget their guids after they resume */
3786         ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3787         if (ret != 16) {
3788                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3789                 goto out_fail;
3790         }
3791
3792         ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3793         if (ret) {
3794                 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3795                 goto out_fail;
3796         }
3797
3798         /*
3799          * For the final step of resuming the topology, we need to bring the
3800          * state of our in-memory topology back into sync with reality. So,
3801          * restart the probing process as if we're probing a new hub
3802          */
3803         queue_work(system_long_wq, &mgr->work);
3804         mutex_unlock(&mgr->lock);
3805
3806         if (sync) {
3807                 drm_dbg_kms(mgr->dev,
3808                             "Waiting for link probe work to finish re-syncing topology...\n");
3809                 flush_work(&mgr->work);
3810         }
3811
3812         return 0;
3813
3814 out_fail:
3815         mutex_unlock(&mgr->lock);
3816         return -1;
3817 }
3818 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3819
3820 static bool
3821 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3822                       struct drm_dp_mst_branch **mstb)
3823 {
3824         int len;
3825         u8 replyblock[32];
3826         int replylen, curreply;
3827         int ret;
3828         u8 hdrlen;
3829         struct drm_dp_sideband_msg_hdr hdr;
3830         struct drm_dp_sideband_msg_rx *msg =
3831                 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3832         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3833                            DP_SIDEBAND_MSG_DOWN_REP_BASE;
3834
3835         if (!up)
3836                 *mstb = NULL;
3837
3838         len = min(mgr->max_dpcd_transaction_bytes, 16);
3839         ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3840         if (ret != len) {
3841                 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3842                 return false;
3843         }
3844
3845         ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3846         if (ret == false) {
3847                 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3848                                1, replyblock, len, false);
3849                 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3850                 return false;
3851         }
3852
3853         if (!up) {
3854                 /* Caller is responsible for giving back this reference */
3855                 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3856                 if (!*mstb) {
3857                         drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3858                         return false;
3859                 }
3860         }
3861
3862         if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3863                 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3864                 return false;
3865         }
3866
3867         replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3868         ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3869         if (!ret) {
3870                 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3871                 return false;
3872         }
3873
3874         replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3875         curreply = len;
3876         while (replylen > 0) {
3877                 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3878                 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3879                                     replyblock, len);
3880                 if (ret != len) {
3881                         drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3882                                     len, ret);
3883                         return false;
3884                 }
3885
3886                 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3887                 if (!ret) {
3888                         drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3889                         return false;
3890                 }
3891
3892                 curreply += len;
3893                 replylen -= len;
3894         }
3895         return true;
3896 }
3897
3898 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3899 {
3900         struct drm_dp_sideband_msg_tx *txmsg;
3901         struct drm_dp_mst_branch *mstb = NULL;
3902         struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3903
3904         if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3905                 goto out_clear_reply;
3906
3907         /* Multi-packet message transmission, don't clear the reply */
3908         if (!msg->have_eomt)
3909                 goto out;
3910
3911         /* find the message */
3912         mutex_lock(&mgr->qlock);
3913         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3914                                          struct drm_dp_sideband_msg_tx, next);
3915         mutex_unlock(&mgr->qlock);
3916
3917         /* Were we actually expecting a response, and from this mstb? */
3918         if (!txmsg || txmsg->dst != mstb) {
3919                 struct drm_dp_sideband_msg_hdr *hdr;
3920
3921                 hdr = &msg->initial_hdr;
3922                 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
3923                             mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
3924                 goto out_clear_reply;
3925         }
3926
3927         drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
3928
3929         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3930                 drm_dbg_kms(mgr->dev,
3931                             "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3932                             txmsg->reply.req_type,
3933                             drm_dp_mst_req_type_str(txmsg->reply.req_type),
3934                             txmsg->reply.u.nak.reason,
3935                             drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3936                             txmsg->reply.u.nak.nak_data);
3937         }
3938
3939         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3940         drm_dp_mst_topology_put_mstb(mstb);
3941
3942         mutex_lock(&mgr->qlock);
3943         txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3944         list_del(&txmsg->next);
3945         mutex_unlock(&mgr->qlock);
3946
3947         wake_up_all(&mgr->tx_waitq);
3948
3949         return 0;
3950
3951 out_clear_reply:
3952         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3953 out:
3954         if (mstb)
3955                 drm_dp_mst_topology_put_mstb(mstb);
3956
3957         return 0;
3958 }
3959
3960 static inline bool
3961 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3962                           struct drm_dp_pending_up_req *up_req)
3963 {
3964         struct drm_dp_mst_branch *mstb = NULL;
3965         struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3966         struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3967         bool hotplug = false, dowork = false;
3968
3969         if (hdr->broadcast) {
3970                 const u8 *guid = NULL;
3971
3972                 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3973                         guid = msg->u.conn_stat.guid;
3974                 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3975                         guid = msg->u.resource_stat.guid;
3976
3977                 if (guid)
3978                         mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3979         } else {
3980                 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3981         }
3982
3983         if (!mstb) {
3984                 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
3985                 return false;
3986         }
3987
3988         /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3989         if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3990                 dowork = drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
3991                 hotplug = true;
3992         }
3993
3994         drm_dp_mst_topology_put_mstb(mstb);
3995
3996         if (dowork)
3997                 queue_work(system_long_wq, &mgr->work);
3998         return hotplug;
3999 }
4000
4001 static void drm_dp_mst_up_req_work(struct work_struct *work)
4002 {
4003         struct drm_dp_mst_topology_mgr *mgr =
4004                 container_of(work, struct drm_dp_mst_topology_mgr,
4005                              up_req_work);
4006         struct drm_dp_pending_up_req *up_req;
4007         bool send_hotplug = false;
4008
4009         mutex_lock(&mgr->probe_lock);
4010         while (true) {
4011                 mutex_lock(&mgr->up_req_lock);
4012                 up_req = list_first_entry_or_null(&mgr->up_req_list,
4013                                                   struct drm_dp_pending_up_req,
4014                                                   next);
4015                 if (up_req)
4016                         list_del(&up_req->next);
4017                 mutex_unlock(&mgr->up_req_lock);
4018
4019                 if (!up_req)
4020                         break;
4021
4022                 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4023                 kfree(up_req);
4024         }
4025         mutex_unlock(&mgr->probe_lock);
4026
4027         if (send_hotplug)
4028                 drm_kms_helper_hotplug_event(mgr->dev);
4029 }
4030
4031 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4032 {
4033         struct drm_dp_pending_up_req *up_req;
4034
4035         if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4036                 goto out;
4037
4038         if (!mgr->up_req_recv.have_eomt)
4039                 return 0;
4040
4041         up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4042         if (!up_req)
4043                 return -ENOMEM;
4044
4045         INIT_LIST_HEAD(&up_req->next);
4046
4047         drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4048
4049         if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4050             up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4051                 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4052                             up_req->msg.req_type);
4053                 kfree(up_req);
4054                 goto out;
4055         }
4056
4057         drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4058                                  false);
4059
4060         if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4061                 const struct drm_dp_connection_status_notify *conn_stat =
4062                         &up_req->msg.u.conn_stat;
4063
4064                 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4065                             conn_stat->port_number,
4066                             conn_stat->legacy_device_plug_status,
4067                             conn_stat->displayport_device_plug_status,
4068                             conn_stat->message_capability_status,
4069                             conn_stat->input_port,
4070                             conn_stat->peer_device_type);
4071         } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4072                 const struct drm_dp_resource_status_notify *res_stat =
4073                         &up_req->msg.u.resource_stat;
4074
4075                 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4076                             res_stat->port_number,
4077                             res_stat->available_pbn);
4078         }
4079
4080         up_req->hdr = mgr->up_req_recv.initial_hdr;
4081         mutex_lock(&mgr->up_req_lock);
4082         list_add_tail(&up_req->next, &mgr->up_req_list);
4083         mutex_unlock(&mgr->up_req_lock);
4084         queue_work(system_long_wq, &mgr->up_req_work);
4085
4086 out:
4087         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4088         return 0;
4089 }
4090
4091 /**
4092  * drm_dp_mst_hpd_irq_handle_event() - MST hotplug IRQ handle MST event
4093  * @mgr: manager to notify irq for.
4094  * @esi: 4 bytes from SINK_COUNT_ESI
4095  * @ack: 4 bytes used to ack events starting from SINK_COUNT_ESI
4096  * @handled: whether the hpd interrupt was consumed or not
4097  *
4098  * This should be called from the driver when it detects a HPD IRQ,
4099  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4100  * topology manager will process the sideband messages received
4101  * as indicated in the DEVICE_SERVICE_IRQ_VECTOR_ESI0 and set the
4102  * corresponding flags that Driver has to ack the DP receiver later.
4103  *
4104  * Note that driver shall also call
4105  * drm_dp_mst_hpd_irq_send_new_request() if the 'handled' is set
4106  * after calling this function, to try to kick off a new request in
4107  * the queue if the previous message transaction is completed.
4108  *
4109  * See also:
4110  * drm_dp_mst_hpd_irq_send_new_request()
4111  */
4112 int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u8 *esi,
4113                                     u8 *ack, bool *handled)
4114 {
4115         int ret = 0;
4116         int sc;
4117         *handled = false;
4118         sc = DP_GET_SINK_COUNT(esi[0]);
4119
4120         if (sc != mgr->sink_count) {
4121                 mgr->sink_count = sc;
4122                 *handled = true;
4123         }
4124
4125         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4126                 ret = drm_dp_mst_handle_down_rep(mgr);
4127                 *handled = true;
4128                 ack[1] |= DP_DOWN_REP_MSG_RDY;
4129         }
4130
4131         if (esi[1] & DP_UP_REQ_MSG_RDY) {
4132                 ret |= drm_dp_mst_handle_up_req(mgr);
4133                 *handled = true;
4134                 ack[1] |= DP_UP_REQ_MSG_RDY;
4135         }
4136
4137         return ret;
4138 }
4139 EXPORT_SYMBOL(drm_dp_mst_hpd_irq_handle_event);
4140
4141 /**
4142  * drm_dp_mst_hpd_irq_send_new_request() - MST hotplug IRQ kick off new request
4143  * @mgr: manager to notify irq for.
4144  *
4145  * This should be called from the driver when mst irq event is handled
4146  * and acked. Note that new down request should only be sent when
4147  * previous message transaction is completed. Source is not supposed to generate
4148  * interleaved message transactions.
4149  */
4150 void drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr *mgr)
4151 {
4152         struct drm_dp_sideband_msg_tx *txmsg;
4153         bool kick = true;
4154
4155         mutex_lock(&mgr->qlock);
4156         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4157                                          struct drm_dp_sideband_msg_tx, next);
4158         /* If last transaction is not completed yet*/
4159         if (!txmsg ||
4160             txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
4161             txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
4162                 kick = false;
4163         mutex_unlock(&mgr->qlock);
4164
4165         if (kick)
4166                 drm_dp_mst_kick_tx(mgr);
4167 }
4168 EXPORT_SYMBOL(drm_dp_mst_hpd_irq_send_new_request);
4169 /**
4170  * drm_dp_mst_detect_port() - get connection status for an MST port
4171  * @connector: DRM connector for this port
4172  * @ctx: The acquisition context to use for grabbing locks
4173  * @mgr: manager for this port
4174  * @port: pointer to a port
4175  *
4176  * This returns the current connection state for a port.
4177  */
4178 int
4179 drm_dp_mst_detect_port(struct drm_connector *connector,
4180                        struct drm_modeset_acquire_ctx *ctx,
4181                        struct drm_dp_mst_topology_mgr *mgr,
4182                        struct drm_dp_mst_port *port)
4183 {
4184         int ret;
4185
4186         /* we need to search for the port in the mgr in case it's gone */
4187         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4188         if (!port)
4189                 return connector_status_disconnected;
4190
4191         ret = drm_modeset_lock(&mgr->base.lock, ctx);
4192         if (ret)
4193                 goto out;
4194
4195         ret = connector_status_disconnected;
4196
4197         if (!port->ddps)
4198                 goto out;
4199
4200         switch (port->pdt) {
4201         case DP_PEER_DEVICE_NONE:
4202                 break;
4203         case DP_PEER_DEVICE_MST_BRANCHING:
4204                 if (!port->mcs)
4205                         ret = connector_status_connected;
4206                 break;
4207
4208         case DP_PEER_DEVICE_SST_SINK:
4209                 ret = connector_status_connected;
4210                 /* for logical ports - cache the EDID */
4211                 if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4212                         port->cached_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4213                 break;
4214         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4215                 if (port->ldps)
4216                         ret = connector_status_connected;
4217                 break;
4218         }
4219 out:
4220         drm_dp_mst_topology_put_port(port);
4221         return ret;
4222 }
4223 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4224
4225 /**
4226  * drm_dp_mst_edid_read() - get EDID for an MST port
4227  * @connector: toplevel connector to get EDID for
4228  * @mgr: manager for this port
4229  * @port: unverified pointer to a port.
4230  *
4231  * This returns an EDID for the port connected to a connector,
4232  * It validates the pointer still exists so the caller doesn't require a
4233  * reference.
4234  */
4235 const struct drm_edid *drm_dp_mst_edid_read(struct drm_connector *connector,
4236                                             struct drm_dp_mst_topology_mgr *mgr,
4237                                             struct drm_dp_mst_port *port)
4238 {
4239         const struct drm_edid *drm_edid;
4240
4241         /* we need to search for the port in the mgr in case it's gone */
4242         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4243         if (!port)
4244                 return NULL;
4245
4246         if (port->cached_edid)
4247                 drm_edid = drm_edid_dup(port->cached_edid);
4248         else
4249                 drm_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4250
4251         drm_dp_mst_topology_put_port(port);
4252
4253         return drm_edid;
4254 }
4255 EXPORT_SYMBOL(drm_dp_mst_edid_read);
4256
4257 /**
4258  * drm_dp_mst_get_edid() - get EDID for an MST port
4259  * @connector: toplevel connector to get EDID for
4260  * @mgr: manager for this port
4261  * @port: unverified pointer to a port.
4262  *
4263  * This function is deprecated; please use drm_dp_mst_edid_read() instead.
4264  *
4265  * This returns an EDID for the port connected to a connector,
4266  * It validates the pointer still exists so the caller doesn't require a
4267  * reference.
4268  */
4269 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector,
4270                                  struct drm_dp_mst_topology_mgr *mgr,
4271                                  struct drm_dp_mst_port *port)
4272 {
4273         const struct drm_edid *drm_edid;
4274         struct edid *edid;
4275
4276         drm_edid = drm_dp_mst_edid_read(connector, mgr, port);
4277
4278         edid = drm_edid_duplicate(drm_edid_raw(drm_edid));
4279
4280         drm_edid_free(drm_edid);
4281
4282         return edid;
4283 }
4284 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4285
4286 /**
4287  * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
4288  * @state: global atomic state
4289  * @mgr: MST topology manager for the port
4290  * @port: port to find time slots for
4291  * @pbn: bandwidth required for the mode in PBN
4292  *
4293  * Allocates time slots to @port, replacing any previous time slot allocations it may
4294  * have had. Any atomic drivers which support MST must call this function in
4295  * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to
4296  * change the current time slot allocation for the new state, and ensure the MST
4297  * atomic state is added whenever the state of payloads in the topology changes.
4298  *
4299  * Allocations set by this function are not checked against the bandwidth
4300  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4301  *
4302  * Additionally, it is OK to call this function multiple times on the same
4303  * @port as needed. It is not OK however, to call this function and
4304  * drm_dp_atomic_release_time_slots() in the same atomic check phase.
4305  *
4306  * See also:
4307  * drm_dp_atomic_release_time_slots()
4308  * drm_dp_mst_atomic_check()
4309  *
4310  * Returns:
4311  * Total slots in the atomic state assigned for this port, or a negative error
4312  * code if the port no longer exists
4313  */
4314 int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
4315                                   struct drm_dp_mst_topology_mgr *mgr,
4316                                   struct drm_dp_mst_port *port, int pbn)
4317 {
4318         struct drm_dp_mst_topology_state *topology_state;
4319         struct drm_dp_mst_atomic_payload *payload = NULL;
4320         struct drm_connector_state *conn_state;
4321         int prev_slots = 0, prev_bw = 0, req_slots;
4322
4323         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4324         if (IS_ERR(topology_state))
4325                 return PTR_ERR(topology_state);
4326
4327         conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4328         topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
4329
4330         /* Find the current allocation for this port, if any */
4331         payload = drm_atomic_get_mst_payload_state(topology_state, port);
4332         if (payload) {
4333                 prev_slots = payload->time_slots;
4334                 prev_bw = payload->pbn;
4335
4336                 /*
4337                  * This should never happen, unless the driver tries
4338                  * releasing and allocating the same timeslot allocation,
4339                  * which is an error
4340                  */
4341                 if (drm_WARN_ON(mgr->dev, payload->delete)) {
4342                         drm_err(mgr->dev,
4343                                 "cannot allocate and release time slots on [MST PORT:%p] in the same state\n",
4344                                 port);
4345                         return -EINVAL;
4346                 }
4347         }
4348
4349         req_slots = DIV_ROUND_UP(dfixed_const(pbn), topology_state->pbn_div.full);
4350
4351         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
4352                        port->connector->base.id, port->connector->name,
4353                        port, prev_slots, req_slots);
4354         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4355                        port->connector->base.id, port->connector->name,
4356                        port, prev_bw, pbn);
4357
4358         /* Add the new allocation to the state, note the VCPI isn't assigned until the end */
4359         if (!payload) {
4360                 payload = kzalloc(sizeof(*payload), GFP_KERNEL);
4361                 if (!payload)
4362                         return -ENOMEM;
4363
4364                 drm_dp_mst_get_port_malloc(port);
4365                 payload->port = port;
4366                 payload->vc_start_slot = -1;
4367                 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_NONE;
4368                 list_add(&payload->next, &topology_state->payloads);
4369         }
4370         payload->time_slots = req_slots;
4371         payload->pbn = pbn;
4372
4373         return req_slots;
4374 }
4375 EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
4376
4377 /**
4378  * drm_dp_atomic_release_time_slots() - Release allocated time slots
4379  * @state: global atomic state
4380  * @mgr: MST topology manager for the port
4381  * @port: The port to release the time slots from
4382  *
4383  * Releases any time slots that have been allocated to a port in the atomic
4384  * state. Any atomic drivers which support MST must call this function
4385  * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback.
4386  * This helper will check whether time slots would be released by the new state and
4387  * respond accordingly, along with ensuring the MST state is always added to the
4388  * atomic state whenever a new state would modify the state of payloads on the
4389  * topology.
4390  *
4391  * It is OK to call this even if @port has been removed from the system.
4392  * Additionally, it is OK to call this function multiple times on the same
4393  * @port as needed. It is not OK however, to call this function and
4394  * drm_dp_atomic_find_time_slots() on the same @port in a single atomic check
4395  * phase.
4396  *
4397  * See also:
4398  * drm_dp_atomic_find_time_slots()
4399  * drm_dp_mst_atomic_check()
4400  *
4401  * Returns:
4402  * 0 on success, negative error code otherwise
4403  */
4404 int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
4405                                      struct drm_dp_mst_topology_mgr *mgr,
4406                                      struct drm_dp_mst_port *port)
4407 {
4408         struct drm_dp_mst_topology_state *topology_state;
4409         struct drm_dp_mst_atomic_payload *payload;
4410         struct drm_connector_state *old_conn_state, *new_conn_state;
4411         bool update_payload = true;
4412
4413         old_conn_state = drm_atomic_get_old_connector_state(state, port->connector);
4414         if (!old_conn_state->crtc)
4415                 return 0;
4416
4417         /* If the CRTC isn't disabled by this state, don't release it's payload */
4418         new_conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4419         if (new_conn_state->crtc) {
4420                 struct drm_crtc_state *crtc_state =
4421                         drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4422
4423                 /* No modeset means no payload changes, so it's safe to not pull in the MST state */
4424                 if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state))
4425                         return 0;
4426
4427                 if (!crtc_state->mode_changed && !crtc_state->connectors_changed)
4428                         update_payload = false;
4429         }
4430
4431         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4432         if (IS_ERR(topology_state))
4433                 return PTR_ERR(topology_state);
4434
4435         topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4436         if (!update_payload)
4437                 return 0;
4438
4439         payload = drm_atomic_get_mst_payload_state(topology_state, port);
4440         if (WARN_ON(!payload)) {
4441                 drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
4442                         port, &topology_state->base);
4443                 return -EINVAL;
4444         }
4445
4446         if (new_conn_state->crtc)
4447                 return 0;
4448
4449         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, payload->time_slots);
4450         if (!payload->delete) {
4451                 payload->pbn = 0;
4452                 payload->delete = true;
4453                 topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
4454         }
4455
4456         return 0;
4457 }
4458 EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
4459
4460 /**
4461  * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
4462  * @state: global atomic state
4463  *
4464  * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
4465  * currently assigned to an MST topology. Drivers must call this hook from their
4466  * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
4467  *
4468  * Returns:
4469  * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
4470  */
4471 int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
4472 {
4473         struct drm_dp_mst_topology_mgr *mgr;
4474         struct drm_dp_mst_topology_state *mst_state;
4475         struct drm_crtc *crtc;
4476         struct drm_crtc_state *crtc_state;
4477         int i, j, commit_idx, num_commit_deps;
4478
4479         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
4480                 if (!mst_state->pending_crtc_mask)
4481                         continue;
4482
4483                 num_commit_deps = hweight32(mst_state->pending_crtc_mask);
4484                 mst_state->commit_deps = kmalloc_array(num_commit_deps,
4485                                                        sizeof(*mst_state->commit_deps), GFP_KERNEL);
4486                 if (!mst_state->commit_deps)
4487                         return -ENOMEM;
4488                 mst_state->num_commit_deps = num_commit_deps;
4489
4490                 commit_idx = 0;
4491                 for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
4492                         if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
4493                                 mst_state->commit_deps[commit_idx++] =
4494                                         drm_crtc_commit_get(crtc_state->commit);
4495                         }
4496                 }
4497         }
4498
4499         return 0;
4500 }
4501 EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
4502
4503 /**
4504  * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies,
4505  * prepare new MST state for commit
4506  * @state: global atomic state
4507  *
4508  * Goes through any MST topologies in this atomic state, and waits for any pending commits which
4509  * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
4510  * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
4511  * with eachother by forcing them to be executed sequentially in situations where the only resources
4512  * the modeset objects in these commits share are an MST topology.
4513  *
4514  * This function also prepares the new MST state for commit by performing some state preparation
4515  * which can't be done until this point, such as reading back the final VC start slots (which are
4516  * determined at commit-time) from the previous state.
4517  *
4518  * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
4519  * or whatever their equivalent of that is.
4520  */
4521 void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
4522 {
4523         struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state;
4524         struct drm_dp_mst_topology_mgr *mgr;
4525         struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
4526         int i, j, ret;
4527
4528         for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) {
4529                 for (j = 0; j < old_mst_state->num_commit_deps; j++) {
4530                         ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
4531                         if (ret < 0)
4532                                 drm_err(state->dev, "Failed to wait for %s: %d\n",
4533                                         old_mst_state->commit_deps[j]->crtc->name, ret);
4534                 }
4535
4536                 /* Now that previous state is committed, it's safe to copy over the start slot
4537                  * and allocation status assignments
4538                  */
4539                 list_for_each_entry(old_payload, &old_mst_state->payloads, next) {
4540                         if (old_payload->delete)
4541                                 continue;
4542
4543                         new_payload = drm_atomic_get_mst_payload_state(new_mst_state,
4544                                                                        old_payload->port);
4545                         new_payload->vc_start_slot = old_payload->vc_start_slot;
4546                         new_payload->payload_allocation_status =
4547                                                         old_payload->payload_allocation_status;
4548                 }
4549         }
4550 }
4551 EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
4552
4553 /**
4554  * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating
4555  * in SST mode
4556  * @new_conn_state: The new connector state of the &drm_connector
4557  * @mgr: The MST topology manager for the &drm_connector
4558  *
4559  * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to
4560  * serialize non-blocking commits happening on the real DP connector of an MST topology switching
4561  * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's
4562  * MST topology will never share the same &drm_encoder.
4563  *
4564  * This function takes care of this serialization issue, by checking a root MST connector's atomic
4565  * state to determine if it is about to have a modeset - and then pulling in the MST topology state
4566  * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask.
4567  *
4568  * Drivers implementing MST must call this function from the
4569  * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of
4570  * driving MST sinks.
4571  *
4572  * Returns:
4573  * 0 on success, negative error code otherwise
4574  */
4575 int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
4576                                       struct drm_dp_mst_topology_mgr *mgr)
4577 {
4578         struct drm_atomic_state *state = new_conn_state->state;
4579         struct drm_connector_state *old_conn_state =
4580                 drm_atomic_get_old_connector_state(state, new_conn_state->connector);
4581         struct drm_crtc_state *crtc_state;
4582         struct drm_dp_mst_topology_state *mst_state = NULL;
4583
4584         if (new_conn_state->crtc) {
4585                 crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4586                 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4587                         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4588                         if (IS_ERR(mst_state))
4589                                 return PTR_ERR(mst_state);
4590
4591                         mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc);
4592                 }
4593         }
4594
4595         if (old_conn_state->crtc) {
4596                 crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc);
4597                 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4598                         if (!mst_state) {
4599                                 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4600                                 if (IS_ERR(mst_state))
4601                                         return PTR_ERR(mst_state);
4602                         }
4603
4604                         mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4605                 }
4606         }
4607
4608         return 0;
4609 }
4610 EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check);
4611
4612 /**
4613  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4614  * @mst_state: mst_state to update
4615  * @link_encoding_cap: the ecoding format on the link
4616  */
4617 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4618 {
4619         if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4620                 mst_state->total_avail_slots = 64;
4621                 mst_state->start_slot = 0;
4622         } else {
4623                 mst_state->total_avail_slots = 63;
4624                 mst_state->start_slot = 1;
4625         }
4626
4627         DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4628                       (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4629                       mst_state);
4630 }
4631 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4632
4633 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4634                                      int id, u8 start_slot, u8 num_slots)
4635 {
4636         u8 payload_alloc[3], status;
4637         int ret;
4638         int retries = 0;
4639
4640         drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4641                            DP_PAYLOAD_TABLE_UPDATED);
4642
4643         payload_alloc[0] = id;
4644         payload_alloc[1] = start_slot;
4645         payload_alloc[2] = num_slots;
4646
4647         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4648         if (ret != 3) {
4649                 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4650                 goto fail;
4651         }
4652
4653 retry:
4654         ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4655         if (ret < 0) {
4656                 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4657                 goto fail;
4658         }
4659
4660         if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4661                 retries++;
4662                 if (retries < 20) {
4663                         usleep_range(10000, 20000);
4664                         goto retry;
4665                 }
4666                 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4667                             status);
4668                 ret = -EINVAL;
4669                 goto fail;
4670         }
4671         ret = 0;
4672 fail:
4673         return ret;
4674 }
4675
4676 static int do_get_act_status(struct drm_dp_aux *aux)
4677 {
4678         int ret;
4679         u8 status;
4680
4681         ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4682         if (ret < 0)
4683                 return ret;
4684
4685         return status;
4686 }
4687
4688 /**
4689  * drm_dp_check_act_status() - Polls for ACT handled status.
4690  * @mgr: manager to use
4691  *
4692  * Tries waiting for the MST hub to finish updating it's payload table by
4693  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4694  * take that long).
4695  *
4696  * Returns:
4697  * 0 if the ACT was handled in time, negative error code on failure.
4698  */
4699 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4700 {
4701         /*
4702          * There doesn't seem to be any recommended retry count or timeout in
4703          * the MST specification. Since some hubs have been observed to take
4704          * over 1 second to update their payload allocations under certain
4705          * conditions, we use a rather large timeout value.
4706          */
4707         const int timeout_ms = 3000;
4708         int ret, status;
4709
4710         ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4711                                  status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4712                                  200, timeout_ms * USEC_PER_MSEC);
4713         if (ret < 0 && status >= 0) {
4714                 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4715                         timeout_ms, status);
4716                 return -EINVAL;
4717         } else if (status < 0) {
4718                 /*
4719                  * Failure here isn't unexpected - the hub may have
4720                  * just been unplugged
4721                  */
4722                 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4723                 return status;
4724         }
4725
4726         return 0;
4727 }
4728 EXPORT_SYMBOL(drm_dp_check_act_status);
4729
4730 /**
4731  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4732  * @clock: dot clock
4733  * @bpp: bpp as .4 binary fixed point
4734  *
4735  * This uses the formula in the spec to calculate the PBN value for a mode.
4736  */
4737 int drm_dp_calc_pbn_mode(int clock, int bpp)
4738 {
4739         /*
4740          * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4741          * common multiplier to render an integer PBN for all link rate/lane
4742          * counts combinations
4743          * calculate
4744          * peak_kbps = clock * bpp / 16
4745          * peak_kbps *= SSC overhead / 1000000
4746          * peak_kbps /= 8    convert to Kbytes
4747          * peak_kBps *= (64/54) / 1000    convert to PBN
4748          */
4749         /*
4750          * TODO: Use the actual link and mode parameters to calculate
4751          * the overhead. For now it's assumed that these are
4752          * 4 link lanes, 4096 hactive pixels, which don't add any
4753          * significant data padding overhead and that there is no DSC
4754          * or FEC overhead.
4755          */
4756         int overhead = drm_dp_bw_overhead(4, 4096, 0, bpp,
4757                                           DRM_DP_BW_OVERHEAD_MST |
4758                                           DRM_DP_BW_OVERHEAD_SSC_REF_CLK);
4759
4760         return DIV64_U64_ROUND_UP(mul_u32_u32(clock * bpp, 64 * overhead >> 4),
4761                                   1000000ULL * 8 * 54 * 1000);
4762 }
4763 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4764
4765 /* we want to kick the TX after we've ack the up/down IRQs. */
4766 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4767 {
4768         queue_work(system_long_wq, &mgr->tx_work);
4769 }
4770
4771 /*
4772  * Helper function for parsing DP device types into convenient strings
4773  * for use with dp_mst_topology
4774  */
4775 static const char *pdt_to_string(u8 pdt)
4776 {
4777         switch (pdt) {
4778         case DP_PEER_DEVICE_NONE:
4779                 return "NONE";
4780         case DP_PEER_DEVICE_SOURCE_OR_SST:
4781                 return "SOURCE OR SST";
4782         case DP_PEER_DEVICE_MST_BRANCHING:
4783                 return "MST BRANCHING";
4784         case DP_PEER_DEVICE_SST_SINK:
4785                 return "SST SINK";
4786         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4787                 return "DP LEGACY CONV";
4788         default:
4789                 return "ERR";
4790         }
4791 }
4792
4793 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4794                                  struct drm_dp_mst_branch *mstb)
4795 {
4796         struct drm_dp_mst_port *port;
4797         int tabs = mstb->lct;
4798         char prefix[10];
4799         int i;
4800
4801         for (i = 0; i < tabs; i++)
4802                 prefix[i] = '\t';
4803         prefix[i] = '\0';
4804
4805         seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4806         list_for_each_entry(port, &mstb->ports, next) {
4807                 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4808                            prefix,
4809                            port->port_num,
4810                            port,
4811                            port->input ? "input" : "output",
4812                            pdt_to_string(port->pdt),
4813                            port->ddps,
4814                            port->ldps,
4815                            port->num_sdp_streams,
4816                            port->num_sdp_stream_sinks,
4817                            port->fec_capable ? "true" : "false",
4818                            port->connector);
4819                 if (port->mstb)
4820                         drm_dp_mst_dump_mstb(m, port->mstb);
4821         }
4822 }
4823
4824 #define DP_PAYLOAD_TABLE_SIZE           64
4825
4826 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4827                                   char *buf)
4828 {
4829         int i;
4830
4831         for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4832                 if (drm_dp_dpcd_read(mgr->aux,
4833                                      DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4834                                      &buf[i], 16) != 16)
4835                         return false;
4836         }
4837         return true;
4838 }
4839
4840 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4841                                struct drm_dp_mst_port *port, char *name,
4842                                int namelen)
4843 {
4844         struct edid *mst_edid;
4845
4846         mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4847         drm_edid_get_monitor_name(mst_edid, name, namelen);
4848         kfree(mst_edid);
4849 }
4850
4851 /**
4852  * drm_dp_mst_dump_topology(): dump topology to seq file.
4853  * @m: seq_file to dump output to
4854  * @mgr: manager to dump current topology for.
4855  *
4856  * helper to dump MST topology to a seq file for debugfs.
4857  */
4858 void drm_dp_mst_dump_topology(struct seq_file *m,
4859                               struct drm_dp_mst_topology_mgr *mgr)
4860 {
4861         struct drm_dp_mst_topology_state *state;
4862         struct drm_dp_mst_atomic_payload *payload;
4863         int i, ret;
4864
4865         static const char *const status[] = {
4866                 "None",
4867                 "Local",
4868                 "DFP",
4869                 "Remote",
4870         };
4871
4872         mutex_lock(&mgr->lock);
4873         if (mgr->mst_primary)
4874                 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4875
4876         /* dump VCPIs */
4877         mutex_unlock(&mgr->lock);
4878
4879         ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
4880         if (ret < 0)
4881                 return;
4882
4883         state = to_drm_dp_mst_topology_state(mgr->base.state);
4884         seq_printf(m, "\n*** Atomic state info ***\n");
4885         seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
4886                    state->payload_mask, mgr->max_payloads, state->start_slot,
4887                    dfixed_trunc(state->pbn_div));
4888
4889         seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | status |     sink name     |\n");
4890         for (i = 0; i < mgr->max_payloads; i++) {
4891                 list_for_each_entry(payload, &state->payloads, next) {
4892                         char name[14];
4893
4894                         if (payload->vcpi != i || payload->delete)
4895                                 continue;
4896
4897                         fetch_monitor_name(mgr, payload->port, name, sizeof(name));
4898                         seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %8s %19s\n",
4899                                    i,
4900                                    payload->port->port_num,
4901                                    payload->vcpi,
4902                                    payload->vc_start_slot,
4903                                    payload->vc_start_slot + payload->time_slots - 1,
4904                                    payload->pbn,
4905                                    payload->dsc_enabled ? "Y" : "N",
4906                                    status[payload->payload_allocation_status],
4907                                    (*name != 0) ? name : "Unknown");
4908                 }
4909         }
4910
4911         seq_printf(m, "\n*** DPCD Info ***\n");
4912         mutex_lock(&mgr->lock);
4913         if (mgr->mst_primary) {
4914                 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4915                 int ret;
4916
4917                 if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4918                         seq_printf(m, "dpcd read failed\n");
4919                         goto out;
4920                 }
4921                 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4922
4923                 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4924                 if (ret != 2) {
4925                         seq_printf(m, "faux/mst read failed\n");
4926                         goto out;
4927                 }
4928                 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4929
4930                 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4931                 if (ret != 1) {
4932                         seq_printf(m, "mst ctrl read failed\n");
4933                         goto out;
4934                 }
4935                 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4936
4937                 /* dump the standard OUI branch header */
4938                 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4939                 if (ret != DP_BRANCH_OUI_HEADER_SIZE) {
4940                         seq_printf(m, "branch oui read failed\n");
4941                         goto out;
4942                 }
4943                 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4944
4945                 for (i = 0x3; i < 0x8 && buf[i]; i++)
4946                         seq_printf(m, "%c", buf[i]);
4947                 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4948                            buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4949                 if (dump_dp_payload_table(mgr, buf))
4950                         seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4951         }
4952
4953 out:
4954         mutex_unlock(&mgr->lock);
4955         drm_modeset_unlock(&mgr->base.lock);
4956 }
4957 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4958
4959 static void drm_dp_tx_work(struct work_struct *work)
4960 {
4961         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4962
4963         mutex_lock(&mgr->qlock);
4964         if (!list_empty(&mgr->tx_msg_downq))
4965                 process_single_down_tx_qlock(mgr);
4966         mutex_unlock(&mgr->qlock);
4967 }
4968
4969 static inline void
4970 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4971 {
4972         drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4973
4974         if (port->connector) {
4975                 drm_connector_unregister(port->connector);
4976                 drm_connector_put(port->connector);
4977         }
4978
4979         drm_dp_mst_put_port_malloc(port);
4980 }
4981
4982 static inline void
4983 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4984 {
4985         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4986         struct drm_dp_mst_port *port, *port_tmp;
4987         struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4988         bool wake_tx = false;
4989
4990         mutex_lock(&mgr->lock);
4991         list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4992                 list_del(&port->next);
4993                 drm_dp_mst_topology_put_port(port);
4994         }
4995         mutex_unlock(&mgr->lock);
4996
4997         /* drop any tx slot msg */
4998         mutex_lock(&mstb->mgr->qlock);
4999         list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
5000                 if (txmsg->dst != mstb)
5001                         continue;
5002
5003                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
5004                 list_del(&txmsg->next);
5005                 wake_tx = true;
5006         }
5007         mutex_unlock(&mstb->mgr->qlock);
5008
5009         if (wake_tx)
5010                 wake_up_all(&mstb->mgr->tx_waitq);
5011
5012         drm_dp_mst_put_mstb_malloc(mstb);
5013 }
5014
5015 static void drm_dp_delayed_destroy_work(struct work_struct *work)
5016 {
5017         struct drm_dp_mst_topology_mgr *mgr =
5018                 container_of(work, struct drm_dp_mst_topology_mgr,
5019                              delayed_destroy_work);
5020         bool send_hotplug = false, go_again;
5021
5022         /*
5023          * Not a regular list traverse as we have to drop the destroy
5024          * connector lock before destroying the mstb/port, to avoid AB->BA
5025          * ordering between this lock and the config mutex.
5026          */
5027         do {
5028                 go_again = false;
5029
5030                 for (;;) {
5031                         struct drm_dp_mst_branch *mstb;
5032
5033                         mutex_lock(&mgr->delayed_destroy_lock);
5034                         mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5035                                                         struct drm_dp_mst_branch,
5036                                                         destroy_next);
5037                         if (mstb)
5038                                 list_del(&mstb->destroy_next);
5039                         mutex_unlock(&mgr->delayed_destroy_lock);
5040
5041                         if (!mstb)
5042                                 break;
5043
5044                         drm_dp_delayed_destroy_mstb(mstb);
5045                         go_again = true;
5046                 }
5047
5048                 for (;;) {
5049                         struct drm_dp_mst_port *port;
5050
5051                         mutex_lock(&mgr->delayed_destroy_lock);
5052                         port = list_first_entry_or_null(&mgr->destroy_port_list,
5053                                                         struct drm_dp_mst_port,
5054                                                         next);
5055                         if (port)
5056                                 list_del(&port->next);
5057                         mutex_unlock(&mgr->delayed_destroy_lock);
5058
5059                         if (!port)
5060                                 break;
5061
5062                         drm_dp_delayed_destroy_port(port);
5063                         send_hotplug = true;
5064                         go_again = true;
5065                 }
5066         } while (go_again);
5067
5068         if (send_hotplug)
5069                 drm_kms_helper_hotplug_event(mgr->dev);
5070 }
5071
5072 static struct drm_private_state *
5073 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5074 {
5075         struct drm_dp_mst_topology_state *state, *old_state =
5076                 to_dp_mst_topology_state(obj->state);
5077         struct drm_dp_mst_atomic_payload *pos, *payload;
5078
5079         state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5080         if (!state)
5081                 return NULL;
5082
5083         __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5084
5085         INIT_LIST_HEAD(&state->payloads);
5086         state->commit_deps = NULL;
5087         state->num_commit_deps = 0;
5088         state->pending_crtc_mask = 0;
5089
5090         list_for_each_entry(pos, &old_state->payloads, next) {
5091                 /* Prune leftover freed timeslot allocations */
5092                 if (pos->delete)
5093                         continue;
5094
5095                 payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
5096                 if (!payload)
5097                         goto fail;
5098
5099                 drm_dp_mst_get_port_malloc(payload->port);
5100                 list_add(&payload->next, &state->payloads);
5101         }
5102
5103         return &state->base;
5104
5105 fail:
5106         list_for_each_entry_safe(pos, payload, &state->payloads, next) {
5107                 drm_dp_mst_put_port_malloc(pos->port);
5108                 kfree(pos);
5109         }
5110         kfree(state);
5111
5112         return NULL;
5113 }
5114
5115 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5116                                      struct drm_private_state *state)
5117 {
5118         struct drm_dp_mst_topology_state *mst_state =
5119                 to_dp_mst_topology_state(state);
5120         struct drm_dp_mst_atomic_payload *pos, *tmp;
5121         int i;
5122
5123         list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
5124                 /* We only keep references to ports with active payloads */
5125                 if (!pos->delete)
5126                         drm_dp_mst_put_port_malloc(pos->port);
5127                 kfree(pos);
5128         }
5129
5130         for (i = 0; i < mst_state->num_commit_deps; i++)
5131                 drm_crtc_commit_put(mst_state->commit_deps[i]);
5132
5133         kfree(mst_state->commit_deps);
5134         kfree(mst_state);
5135 }
5136
5137 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5138                                                  struct drm_dp_mst_branch *branch)
5139 {
5140         while (port->parent) {
5141                 if (port->parent == branch)
5142                         return true;
5143
5144                 if (port->parent->port_parent)
5145                         port = port->parent->port_parent;
5146                 else
5147                         break;
5148         }
5149         return false;
5150 }
5151
5152 static bool
5153 drm_dp_mst_port_downstream_of_parent_locked(struct drm_dp_mst_topology_mgr *mgr,
5154                                             struct drm_dp_mst_port *port,
5155                                             struct drm_dp_mst_port *parent)
5156 {
5157         if (!mgr->mst_primary)
5158                 return false;
5159
5160         port = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,
5161                                                              port);
5162         if (!port)
5163                 return false;
5164
5165         if (!parent)
5166                 return true;
5167
5168         parent = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,
5169                                                                parent);
5170         if (!parent)
5171                 return false;
5172
5173         if (!parent->mstb)
5174                 return false;
5175
5176         return drm_dp_mst_port_downstream_of_branch(port, parent->mstb);
5177 }
5178
5179 /**
5180  * drm_dp_mst_port_downstream_of_parent - check if a port is downstream of a parent port
5181  * @mgr: MST topology manager
5182  * @port: the port being looked up
5183  * @parent: the parent port
5184  *
5185  * The function returns %true if @port is downstream of @parent. If @parent is
5186  * %NULL - denoting the root port - the function returns %true if @port is in
5187  * @mgr's topology.
5188  */
5189 bool
5190 drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr,
5191                                      struct drm_dp_mst_port *port,
5192                                      struct drm_dp_mst_port *parent)
5193 {
5194         bool ret;
5195
5196         mutex_lock(&mgr->lock);
5197         ret = drm_dp_mst_port_downstream_of_parent_locked(mgr, port, parent);
5198         mutex_unlock(&mgr->lock);
5199
5200         return ret;
5201 }
5202 EXPORT_SYMBOL(drm_dp_mst_port_downstream_of_parent);
5203
5204 static int
5205 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5206                                       struct drm_dp_mst_topology_state *state,
5207                                       struct drm_dp_mst_port **failing_port);
5208
5209 static int
5210 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5211                                       struct drm_dp_mst_topology_state *state,
5212                                       struct drm_dp_mst_port **failing_port)
5213 {
5214         struct drm_dp_mst_atomic_payload *payload;
5215         struct drm_dp_mst_port *port;
5216         int pbn_used = 0, ret;
5217         bool found = false;
5218
5219         /* Check that we have at least one port in our state that's downstream
5220          * of this branch, otherwise we can skip this branch
5221          */
5222         list_for_each_entry(payload, &state->payloads, next) {
5223                 if (!payload->pbn ||
5224                     !drm_dp_mst_port_downstream_of_branch(payload->port, mstb))
5225                         continue;
5226
5227                 found = true;
5228                 break;
5229         }
5230         if (!found)
5231                 return 0;
5232
5233         if (mstb->port_parent)
5234                 drm_dbg_atomic(mstb->mgr->dev,
5235                                "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5236                                mstb->port_parent->parent, mstb->port_parent, mstb);
5237         else
5238                 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5239
5240         list_for_each_entry(port, &mstb->ports, next) {
5241                 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state, failing_port);
5242                 if (ret < 0)
5243                         return ret;
5244
5245                 pbn_used += ret;
5246         }
5247
5248         return pbn_used;
5249 }
5250
5251 static int
5252 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5253                                       struct drm_dp_mst_topology_state *state,
5254                                       struct drm_dp_mst_port **failing_port)
5255 {
5256         struct drm_dp_mst_atomic_payload *payload;
5257         int pbn_used = 0;
5258
5259         if (port->pdt == DP_PEER_DEVICE_NONE)
5260                 return 0;
5261
5262         if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5263                 payload = drm_atomic_get_mst_payload_state(state, port);
5264                 if (!payload)
5265                         return 0;
5266
5267                 /*
5268                  * This could happen if the sink deasserted its HPD line, but
5269                  * the branch device still reports it as attached (PDT != NONE).
5270                  */
5271                 if (!port->full_pbn) {
5272                         drm_dbg_atomic(port->mgr->dev,
5273                                        "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5274                                        port->parent, port);
5275                         *failing_port = port;
5276                         return -EINVAL;
5277                 }
5278
5279                 pbn_used = payload->pbn;
5280         } else {
5281                 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5282                                                                  state,
5283                                                                  failing_port);
5284                 if (pbn_used <= 0)
5285                         return pbn_used;
5286         }
5287
5288         if (pbn_used > port->full_pbn) {
5289                 drm_dbg_atomic(port->mgr->dev,
5290                                "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5291                                port->parent, port, pbn_used, port->full_pbn);
5292                 *failing_port = port;
5293                 return -ENOSPC;
5294         }
5295
5296         drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5297                        port->parent, port, pbn_used, port->full_pbn);
5298
5299         return pbn_used;
5300 }
5301
5302 static inline int
5303 drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr,
5304                                              struct drm_dp_mst_topology_state *mst_state)
5305 {
5306         struct drm_dp_mst_atomic_payload *payload;
5307         int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5308
5309         list_for_each_entry(payload, &mst_state->payloads, next) {
5310                 /* Releasing payloads is always OK-even if the port is gone */
5311                 if (payload->delete) {
5312                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n",
5313                                        payload->port);
5314                         continue;
5315                 }
5316
5317                 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n",
5318                                payload->port, payload->time_slots);
5319
5320                 avail_slots -= payload->time_slots;
5321                 if (avail_slots < 0) {
5322                         drm_dbg_atomic(mgr->dev,
5323                                        "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n",
5324                                        payload->port, mst_state, avail_slots + payload->time_slots);
5325                         return -ENOSPC;
5326                 }
5327
5328                 if (++payload_count > mgr->max_payloads) {
5329                         drm_dbg_atomic(mgr->dev,
5330                                        "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5331                                        mgr, mst_state, mgr->max_payloads);
5332                         return -EINVAL;
5333                 }
5334
5335                 /* Assign a VCPI */
5336                 if (!payload->vcpi) {
5337                         payload->vcpi = ffz(mst_state->payload_mask) + 1;
5338                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n",
5339                                        payload->port, payload->vcpi);
5340                         mst_state->payload_mask |= BIT(payload->vcpi - 1);
5341                 }
5342         }
5343
5344         if (!payload_count)
5345                 mst_state->pbn_div.full = dfixed_const(0);
5346
5347         drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
5348                        mgr, mst_state, dfixed_trunc(mst_state->pbn_div), avail_slots,
5349                        mst_state->total_avail_slots - avail_slots);
5350
5351         return 0;
5352 }
5353
5354 /**
5355  * drm_dp_mst_add_affected_dsc_crtcs
5356  * @state: Pointer to the new struct drm_dp_mst_topology_state
5357  * @mgr: MST topology manager
5358  *
5359  * Whenever there is a change in mst topology
5360  * DSC configuration would have to be recalculated
5361  * therefore we need to trigger modeset on all affected
5362  * CRTCs in that topology
5363  *
5364  * See also:
5365  * drm_dp_mst_atomic_enable_dsc()
5366  */
5367 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5368 {
5369         struct drm_dp_mst_topology_state *mst_state;
5370         struct drm_dp_mst_atomic_payload *pos;
5371         struct drm_connector *connector;
5372         struct drm_connector_state *conn_state;
5373         struct drm_crtc *crtc;
5374         struct drm_crtc_state *crtc_state;
5375
5376         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5377
5378         if (IS_ERR(mst_state))
5379                 return PTR_ERR(mst_state);
5380
5381         list_for_each_entry(pos, &mst_state->payloads, next) {
5382
5383                 connector = pos->port->connector;
5384
5385                 if (!connector)
5386                         return -EINVAL;
5387
5388                 conn_state = drm_atomic_get_connector_state(state, connector);
5389
5390                 if (IS_ERR(conn_state))
5391                         return PTR_ERR(conn_state);
5392
5393                 crtc = conn_state->crtc;
5394
5395                 if (!crtc)
5396                         continue;
5397
5398                 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5399                         continue;
5400
5401                 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5402
5403                 if (IS_ERR(crtc_state))
5404                         return PTR_ERR(crtc_state);
5405
5406                 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5407                                mgr, crtc);
5408
5409                 crtc_state->mode_changed = true;
5410         }
5411         return 0;
5412 }
5413 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5414
5415 /**
5416  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5417  * @state: Pointer to the new drm_atomic_state
5418  * @port: Pointer to the affected MST Port
5419  * @pbn: Newly recalculated bw required for link with DSC enabled
5420  * @enable: Boolean flag to enable or disable DSC on the port
5421  *
5422  * This function enables DSC on the given Port
5423  * by recalculating its vcpi from pbn provided
5424  * and sets dsc_enable flag to keep track of which
5425  * ports have DSC enabled
5426  *
5427  */
5428 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5429                                  struct drm_dp_mst_port *port,
5430                                  int pbn, bool enable)
5431 {
5432         struct drm_dp_mst_topology_state *mst_state;
5433         struct drm_dp_mst_atomic_payload *payload;
5434         int time_slots = 0;
5435
5436         mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5437         if (IS_ERR(mst_state))
5438                 return PTR_ERR(mst_state);
5439
5440         payload = drm_atomic_get_mst_payload_state(mst_state, port);
5441         if (!payload) {
5442                 drm_dbg_atomic(state->dev,
5443                                "[MST PORT:%p] Couldn't find payload in mst state %p\n",
5444                                port, mst_state);
5445                 return -EINVAL;
5446         }
5447
5448         if (payload->dsc_enabled == enable) {
5449                 drm_dbg_atomic(state->dev,
5450                                "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n",
5451                                port, enable, payload->time_slots);
5452                 time_slots = payload->time_slots;
5453         }
5454
5455         if (enable) {
5456                 time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn);
5457                 drm_dbg_atomic(state->dev,
5458                                "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
5459                                port, time_slots);
5460                 if (time_slots < 0)
5461                         return -EINVAL;
5462         }
5463
5464         payload->dsc_enabled = enable;
5465
5466         return time_slots;
5467 }
5468 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5469
5470 /**
5471  * drm_dp_mst_atomic_check_mgr - Check the atomic state of an MST topology manager
5472  * @state: The global atomic state
5473  * @mgr: Manager to check
5474  * @mst_state: The MST atomic state for @mgr
5475  * @failing_port: Returns the port with a BW limitation
5476  *
5477  * Checks the given MST manager's topology state for an atomic update to ensure
5478  * that it's valid. This includes checking whether there's enough bandwidth to
5479  * support the new timeslot allocations in the atomic update.
5480  *
5481  * Any atomic drivers supporting DP MST must make sure to call this or
5482  * the drm_dp_mst_atomic_check() function after checking the rest of their state
5483  * in their &drm_mode_config_funcs.atomic_check() callback.
5484  *
5485  * See also:
5486  * drm_dp_mst_atomic_check()
5487  * drm_dp_atomic_find_time_slots()
5488  * drm_dp_atomic_release_time_slots()
5489  *
5490  * Returns:
5491  *   - 0 if the new state is valid
5492  *   - %-ENOSPC, if the new state is invalid, because of BW limitation
5493  *         @failing_port is set to:
5494  *         - The non-root port where a BW limit check failed
5495  *           with all the ports downstream of @failing_port passing
5496  *           the BW limit check.
5497  *           The returned port pointer is valid until at least
5498  *           one payload downstream of it exists.
5499  *         - %NULL if the BW limit check failed at the root port
5500  *           with all the ports downstream of the root port passing
5501  *           the BW limit check.
5502  *   - %-EINVAL, if the new state is invalid, because the root port has
5503  *     too many payloads.
5504  */
5505 int drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state,
5506                                 struct drm_dp_mst_topology_mgr *mgr,
5507                                 struct drm_dp_mst_topology_state *mst_state,
5508                                 struct drm_dp_mst_port **failing_port)
5509 {
5510         int ret;
5511
5512         *failing_port = NULL;
5513
5514         if (!mgr->mst_state)
5515                 return 0;
5516
5517         mutex_lock(&mgr->lock);
5518         ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5519                                                     mst_state,
5520                                                     failing_port);
5521         mutex_unlock(&mgr->lock);
5522
5523         if (ret < 0)
5524                 return ret;
5525
5526         return drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
5527 }
5528 EXPORT_SYMBOL(drm_dp_mst_atomic_check_mgr);
5529
5530 /**
5531  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5532  * atomic update is valid
5533  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5534  *
5535  * Checks the given topology state for an atomic update to ensure that it's
5536  * valid, calling drm_dp_mst_atomic_check_mgr() for all MST manager in the
5537  * atomic state. This includes checking whether there's enough bandwidth to
5538  * support the new timeslot allocations in the atomic update.
5539  *
5540  * Any atomic drivers supporting DP MST must make sure to call this after
5541  * checking the rest of their state in their
5542  * &drm_mode_config_funcs.atomic_check() callback.
5543  *
5544  * See also:
5545  * drm_dp_mst_atomic_check_mgr()
5546  * drm_dp_atomic_find_time_slots()
5547  * drm_dp_atomic_release_time_slots()
5548  *
5549  * Returns:
5550  *
5551  * 0 if the new state is valid, negative error code otherwise.
5552  */
5553 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5554 {
5555         struct drm_dp_mst_topology_mgr *mgr;
5556         struct drm_dp_mst_topology_state *mst_state;
5557         int i, ret = 0;
5558
5559         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5560                 struct drm_dp_mst_port *tmp_port;
5561
5562                 ret = drm_dp_mst_atomic_check_mgr(state, mgr, mst_state, &tmp_port);
5563                 if (ret)
5564                         break;
5565         }
5566
5567         return ret;
5568 }
5569 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5570
5571 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5572         .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5573         .atomic_destroy_state = drm_dp_mst_destroy_state,
5574 };
5575 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5576
5577 /**
5578  * drm_atomic_get_mst_topology_state: get MST topology state
5579  * @state: global atomic state
5580  * @mgr: MST topology manager, also the private object in this case
5581  *
5582  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5583  * state vtable so that the private object state returned is that of a MST
5584  * topology object.
5585  *
5586  * RETURNS:
5587  *
5588  * The MST topology state or error pointer.
5589  */
5590 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5591                                                                     struct drm_dp_mst_topology_mgr *mgr)
5592 {
5593         return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5594 }
5595 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5596
5597 /**
5598  * drm_atomic_get_old_mst_topology_state: get old MST topology state in atomic state, if any
5599  * @state: global atomic state
5600  * @mgr: MST topology manager, also the private object in this case
5601  *
5602  * This function wraps drm_atomic_get_old_private_obj_state() passing in the MST atomic
5603  * state vtable so that the private object state returned is that of a MST
5604  * topology object.
5605  *
5606  * Returns:
5607  *
5608  * The old MST topology state, or NULL if there's no topology state for this MST mgr
5609  * in the global atomic state
5610  */
5611 struct drm_dp_mst_topology_state *
5612 drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
5613                                       struct drm_dp_mst_topology_mgr *mgr)
5614 {
5615         struct drm_private_state *old_priv_state =
5616                 drm_atomic_get_old_private_obj_state(state, &mgr->base);
5617
5618         return old_priv_state ? to_dp_mst_topology_state(old_priv_state) : NULL;
5619 }
5620 EXPORT_SYMBOL(drm_atomic_get_old_mst_topology_state);
5621
5622 /**
5623  * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
5624  * @state: global atomic state
5625  * @mgr: MST topology manager, also the private object in this case
5626  *
5627  * This function wraps drm_atomic_get_new_private_obj_state() passing in the MST atomic
5628  * state vtable so that the private object state returned is that of a MST
5629  * topology object.
5630  *
5631  * Returns:
5632  *
5633  * The new MST topology state, or NULL if there's no topology state for this MST mgr
5634  * in the global atomic state
5635  */
5636 struct drm_dp_mst_topology_state *
5637 drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
5638                                       struct drm_dp_mst_topology_mgr *mgr)
5639 {
5640         struct drm_private_state *new_priv_state =
5641                 drm_atomic_get_new_private_obj_state(state, &mgr->base);
5642
5643         return new_priv_state ? to_dp_mst_topology_state(new_priv_state) : NULL;
5644 }
5645 EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
5646
5647 /**
5648  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5649  * @mgr: manager struct to initialise
5650  * @dev: device providing this structure - for i2c addition.
5651  * @aux: DP helper aux channel to talk to this device
5652  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5653  * @max_payloads: maximum number of payloads this GPU can source
5654  * @conn_base_id: the connector object ID the MST device is connected to.
5655  *
5656  * Return 0 for success, or negative error code on failure
5657  */
5658 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5659                                  struct drm_device *dev, struct drm_dp_aux *aux,
5660                                  int max_dpcd_transaction_bytes, int max_payloads,
5661                                  int conn_base_id)
5662 {
5663         struct drm_dp_mst_topology_state *mst_state;
5664
5665         mutex_init(&mgr->lock);
5666         mutex_init(&mgr->qlock);
5667         mutex_init(&mgr->delayed_destroy_lock);
5668         mutex_init(&mgr->up_req_lock);
5669         mutex_init(&mgr->probe_lock);
5670 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5671         mutex_init(&mgr->topology_ref_history_lock);
5672         stack_depot_init();
5673 #endif
5674         INIT_LIST_HEAD(&mgr->tx_msg_downq);
5675         INIT_LIST_HEAD(&mgr->destroy_port_list);
5676         INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5677         INIT_LIST_HEAD(&mgr->up_req_list);
5678
5679         /*
5680          * delayed_destroy_work will be queued on a dedicated WQ, so that any
5681          * requeuing will be also flushed when deiniting the topology manager.
5682          */
5683         mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5684         if (mgr->delayed_destroy_wq == NULL)
5685                 return -ENOMEM;
5686
5687         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5688         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5689         INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5690         INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5691         init_waitqueue_head(&mgr->tx_waitq);
5692         mgr->dev = dev;
5693         mgr->aux = aux;
5694         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5695         mgr->max_payloads = max_payloads;
5696         mgr->conn_base_id = conn_base_id;
5697
5698         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5699         if (mst_state == NULL)
5700                 return -ENOMEM;
5701
5702         mst_state->total_avail_slots = 63;
5703         mst_state->start_slot = 1;
5704
5705         mst_state->mgr = mgr;
5706         INIT_LIST_HEAD(&mst_state->payloads);
5707
5708         drm_atomic_private_obj_init(dev, &mgr->base,
5709                                     &mst_state->base,
5710                                     &drm_dp_mst_topology_state_funcs);
5711
5712         return 0;
5713 }
5714 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5715
5716 /**
5717  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5718  * @mgr: manager to destroy
5719  */
5720 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5721 {
5722         drm_dp_mst_topology_mgr_set_mst(mgr, false);
5723         flush_work(&mgr->work);
5724         /* The following will also drain any requeued work on the WQ. */
5725         if (mgr->delayed_destroy_wq) {
5726                 destroy_workqueue(mgr->delayed_destroy_wq);
5727                 mgr->delayed_destroy_wq = NULL;
5728         }
5729         mgr->dev = NULL;
5730         mgr->aux = NULL;
5731         drm_atomic_private_obj_fini(&mgr->base);
5732         mgr->funcs = NULL;
5733
5734         mutex_destroy(&mgr->delayed_destroy_lock);
5735         mutex_destroy(&mgr->qlock);
5736         mutex_destroy(&mgr->lock);
5737         mutex_destroy(&mgr->up_req_lock);
5738         mutex_destroy(&mgr->probe_lock);
5739 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5740         mutex_destroy(&mgr->topology_ref_history_lock);
5741 #endif
5742 }
5743 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5744
5745 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5746 {
5747         int i;
5748
5749         if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5750                 return false;
5751
5752         for (i = 0; i < num - 1; i++) {
5753                 if (msgs[i].flags & I2C_M_RD ||
5754                     msgs[i].len > 0xff)
5755                         return false;
5756         }
5757
5758         return msgs[num - 1].flags & I2C_M_RD &&
5759                 msgs[num - 1].len <= 0xff;
5760 }
5761
5762 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5763 {
5764         int i;
5765
5766         for (i = 0; i < num - 1; i++) {
5767                 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5768                     msgs[i].len > 0xff)
5769                         return false;
5770         }
5771
5772         return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5773 }
5774
5775 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5776                                struct drm_dp_mst_port *port,
5777                                struct i2c_msg *msgs, int num)
5778 {
5779         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5780         unsigned int i;
5781         struct drm_dp_sideband_msg_req_body msg;
5782         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5783         int ret;
5784
5785         memset(&msg, 0, sizeof(msg));
5786         msg.req_type = DP_REMOTE_I2C_READ;
5787         msg.u.i2c_read.num_transactions = num - 1;
5788         msg.u.i2c_read.port_number = port->port_num;
5789         for (i = 0; i < num - 1; i++) {
5790                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5791                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5792                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5793                 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5794         }
5795         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5796         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5797
5798         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5799         if (!txmsg) {
5800                 ret = -ENOMEM;
5801                 goto out;
5802         }
5803
5804         txmsg->dst = mstb;
5805         drm_dp_encode_sideband_req(&msg, txmsg);
5806
5807         drm_dp_queue_down_tx(mgr, txmsg);
5808
5809         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5810         if (ret > 0) {
5811
5812                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5813                         ret = -EREMOTEIO;
5814                         goto out;
5815                 }
5816                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5817                         ret = -EIO;
5818                         goto out;
5819                 }
5820                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5821                 ret = num;
5822         }
5823 out:
5824         kfree(txmsg);
5825         return ret;
5826 }
5827
5828 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5829                                 struct drm_dp_mst_port *port,
5830                                 struct i2c_msg *msgs, int num)
5831 {
5832         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5833         unsigned int i;
5834         struct drm_dp_sideband_msg_req_body msg;
5835         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5836         int ret;
5837
5838         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5839         if (!txmsg) {
5840                 ret = -ENOMEM;
5841                 goto out;
5842         }
5843         for (i = 0; i < num; i++) {
5844                 memset(&msg, 0, sizeof(msg));
5845                 msg.req_type = DP_REMOTE_I2C_WRITE;
5846                 msg.u.i2c_write.port_number = port->port_num;
5847                 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5848                 msg.u.i2c_write.num_bytes = msgs[i].len;
5849                 msg.u.i2c_write.bytes = msgs[i].buf;
5850
5851                 memset(txmsg, 0, sizeof(*txmsg));
5852                 txmsg->dst = mstb;
5853
5854                 drm_dp_encode_sideband_req(&msg, txmsg);
5855                 drm_dp_queue_down_tx(mgr, txmsg);
5856
5857                 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5858                 if (ret > 0) {
5859                         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5860                                 ret = -EREMOTEIO;
5861                                 goto out;
5862                         }
5863                 } else {
5864                         goto out;
5865                 }
5866         }
5867         ret = num;
5868 out:
5869         kfree(txmsg);
5870         return ret;
5871 }
5872
5873 /* I2C device */
5874 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5875                                struct i2c_msg *msgs, int num)
5876 {
5877         struct drm_dp_aux *aux = adapter->algo_data;
5878         struct drm_dp_mst_port *port =
5879                 container_of(aux, struct drm_dp_mst_port, aux);
5880         struct drm_dp_mst_branch *mstb;
5881         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5882         int ret;
5883
5884         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5885         if (!mstb)
5886                 return -EREMOTEIO;
5887
5888         if (remote_i2c_read_ok(msgs, num)) {
5889                 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5890         } else if (remote_i2c_write_ok(msgs, num)) {
5891                 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5892         } else {
5893                 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5894                 ret = -EIO;
5895         }
5896
5897         drm_dp_mst_topology_put_mstb(mstb);
5898         return ret;
5899 }
5900
5901 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5902 {
5903         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5904                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5905                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5906                I2C_FUNC_10BIT_ADDR;
5907 }
5908
5909 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5910         .functionality = drm_dp_mst_i2c_functionality,
5911         .master_xfer = drm_dp_mst_i2c_xfer,
5912 };
5913
5914 /**
5915  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5916  * @port: The port to add the I2C bus on
5917  *
5918  * Returns 0 on success or a negative error code on failure.
5919  */
5920 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5921 {
5922         struct drm_dp_aux *aux = &port->aux;
5923         struct device *parent_dev = port->mgr->dev->dev;
5924
5925         aux->ddc.algo = &drm_dp_mst_i2c_algo;
5926         aux->ddc.algo_data = aux;
5927         aux->ddc.retries = 3;
5928
5929         aux->ddc.owner = THIS_MODULE;
5930         /* FIXME: set the kdev of the port's connector as parent */
5931         aux->ddc.dev.parent = parent_dev;
5932         aux->ddc.dev.of_node = parent_dev->of_node;
5933
5934         strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5935                 sizeof(aux->ddc.name));
5936
5937         return i2c_add_adapter(&aux->ddc);
5938 }
5939
5940 /**
5941  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5942  * @port: The port to remove the I2C bus from
5943  */
5944 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5945 {
5946         i2c_del_adapter(&port->aux.ddc);
5947 }
5948
5949 /**
5950  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5951  * @port: The port to check
5952  *
5953  * A single physical MST hub object can be represented in the topology
5954  * by multiple branches, with virtual ports between those branches.
5955  *
5956  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5957  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5958  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5959  *
5960  * May acquire mgr->lock
5961  *
5962  * Returns:
5963  * true if the port is a virtual DP peer device, false otherwise
5964  */
5965 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5966 {
5967         struct drm_dp_mst_port *downstream_port;
5968
5969         if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5970                 return false;
5971
5972         /* Virtual DP Sink (Internal Display Panel) */
5973         if (port->port_num >= 8)
5974                 return true;
5975
5976         /* DP-to-HDMI Protocol Converter */
5977         if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5978             !port->mcs &&
5979             port->ldps)
5980                 return true;
5981
5982         /* DP-to-DP */
5983         mutex_lock(&port->mgr->lock);
5984         if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5985             port->mstb &&
5986             port->mstb->num_ports == 2) {
5987                 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5988                         if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5989                             !downstream_port->input) {
5990                                 mutex_unlock(&port->mgr->lock);
5991                                 return true;
5992                         }
5993                 }
5994         }
5995         mutex_unlock(&port->mgr->lock);
5996
5997         return false;
5998 }
5999
6000 /**
6001  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
6002  * @port: The port to check. A leaf of the MST tree with an attached display.
6003  *
6004  * Depending on the situation, DSC may be enabled via the endpoint aux,
6005  * the immediately upstream aux, or the connector's physical aux.
6006  *
6007  * This is both the correct aux to read DSC_CAPABILITY and the
6008  * correct aux to write DSC_ENABLED.
6009  *
6010  * This operation can be expensive (up to four aux reads), so
6011  * the caller should cache the return.
6012  *
6013  * Returns:
6014  * NULL if DSC cannot be enabled on this port, otherwise the aux device
6015  */
6016 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
6017 {
6018         struct drm_dp_mst_port *immediate_upstream_port;
6019         struct drm_dp_aux *immediate_upstream_aux;
6020         struct drm_dp_mst_port *fec_port;
6021         struct drm_dp_desc desc = {};
6022         u8 endpoint_fec;
6023         u8 endpoint_dsc;
6024
6025         if (!port)
6026                 return NULL;
6027
6028         if (port->parent->port_parent)
6029                 immediate_upstream_port = port->parent->port_parent;
6030         else
6031                 immediate_upstream_port = NULL;
6032
6033         fec_port = immediate_upstream_port;
6034         while (fec_port) {
6035                 /*
6036                  * Each physical link (i.e. not a virtual port) between the
6037                  * output and the primary device must support FEC
6038                  */
6039                 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
6040                     !fec_port->fec_capable)
6041                         return NULL;
6042
6043                 fec_port = fec_port->parent->port_parent;
6044         }
6045
6046         /* DP-to-DP peer device */
6047         if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
6048                 u8 upstream_dsc;
6049
6050                 if (drm_dp_dpcd_read(&port->aux,
6051                                      DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
6052                         return NULL;
6053                 if (drm_dp_dpcd_read(&port->aux,
6054                                      DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
6055                         return NULL;
6056                 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
6057                                      DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
6058                         return NULL;
6059
6060                 /* Enpoint decompression with DP-to-DP peer device */
6061                 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
6062                     (endpoint_fec & DP_FEC_CAPABLE) &&
6063                     (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) {
6064                         port->passthrough_aux = &immediate_upstream_port->aux;
6065                         return &port->aux;
6066                 }
6067
6068                 /* Virtual DPCD decompression with DP-to-DP peer device */
6069                 return &immediate_upstream_port->aux;
6070         }
6071
6072         /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
6073         if (drm_dp_mst_is_virtual_dpcd(port))
6074                 return &port->aux;
6075
6076         /*
6077          * Synaptics quirk
6078          * Applies to ports for which:
6079          * - Physical aux has Synaptics OUI
6080          * - DPv1.4 or higher
6081          * - Port is on primary branch device
6082          * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
6083          */
6084         if (immediate_upstream_port)
6085                 immediate_upstream_aux = &immediate_upstream_port->aux;
6086         else
6087                 immediate_upstream_aux = port->mgr->aux;
6088
6089         if (drm_dp_read_desc(immediate_upstream_aux, &desc, true))
6090                 return NULL;
6091
6092         if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD)) {
6093                 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
6094
6095                 if (drm_dp_read_dpcd_caps(immediate_upstream_aux, dpcd_ext) < 0)
6096                         return NULL;
6097
6098                 if (dpcd_ext[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
6099                     ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
6100                     ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
6101                      != DP_DWN_STRM_PORT_TYPE_ANALOG)))
6102                         return immediate_upstream_aux;
6103         }
6104
6105         /*
6106          * The check below verifies if the MST sink
6107          * connected to the GPU is capable of DSC -
6108          * therefore the endpoint needs to be
6109          * both DSC and FEC capable.
6110          */
6111         if (drm_dp_dpcd_read(&port->aux,
6112            DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
6113                 return NULL;
6114         if (drm_dp_dpcd_read(&port->aux,
6115            DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
6116                 return NULL;
6117         if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
6118            (endpoint_fec & DP_FEC_CAPABLE))
6119                 return &port->aux;
6120
6121         return NULL;
6122 }
6123 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);