drivers/misc/ti-st/st_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Shared Transport Line discipline driver Core
   4  *      This hooks up ST KIM driver and ST LL driver
   5  *  Copyright (C) 2009-2010 Texas Instruments
   6  *  Author: Pavan Savoy <pavan_savoy@ti.com>
   7  */
   8
   9 #define pr_fmt(fmt)     "(stc): " fmt
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/tty.h>
  13
  14 #include <linux/seq_file.h>
  15 #include <linux/skbuff.h>
  16
  17 #include <linux/ti_wilink_st.h>
  18
  19 /*
  20  * function pointer pointing to either,
  21  * st_kim_recv during registration to receive fw download responses
  22  * st_int_recv after registration to receive proto stack responses
  23  */
  24 static void (*st_recv)(void *disc_data, const u8 *ptr, size_t count);
  25
  26 /********************************************************************/
  27 static void add_channel_to_table(struct st_data_s *st_gdata,
  28                 struct st_proto_s *new_proto)
  29 {
  30         pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
  31         /* list now has the channel id as index itself */
  32         st_gdata->list[new_proto->chnl_id] = new_proto;
  33         st_gdata->is_registered[new_proto->chnl_id] = true;
  34 }
  35
  36 static void remove_channel_from_table(struct st_data_s *st_gdata,
  37                 struct st_proto_s *proto)
  38 {
  39         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  40 /*      st_gdata->list[proto->chnl_id] = NULL; */
  41         st_gdata->is_registered[proto->chnl_id] = false;
  42 }
  43
  44 /*
  45  * called from KIM during firmware download.
  46  *
  47  * This is a wrapper function to tty->ops->write_room.
  48  * It returns number of free space available in
  49  * uart tx buffer.
  50  */
  51 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  52 {
  53         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  54                 pr_err("tty unavailable to perform write");
  55                 return -1;
  56         }
  57
  58         return tty_write_room(st_gdata->tty);
  59 }
  60
  61 /*
  62  * can be called in from
  63  * -- KIM (during fw download)
  64  * -- ST Core (during st_write)
  65  *
  66  *  This is the internal write function - a wrapper
  67  *  to tty->ops->write
  68  */
  69 int st_int_write(struct st_data_s *st_gdata,
  70         const unsigned char *data, int count)
  71 {
  72         struct tty_struct *tty;
  73         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  74                 pr_err("tty unavailable to perform write");
  75                 return -EINVAL;
  76         }
  77         tty = st_gdata->tty;
  78 #ifdef VERBOSE
  79         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  80                 16, 1, data, count, 0);
  81 #endif
  82         return tty->ops->write(tty, data, count);
  83
  84 }
  85
  86 /*
  87  * push the skb received to relevant
  88  * protocol stacks
  89  */
  90 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
  91 {
  92         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
  93
  94         if (unlikely
  95             (st_gdata == NULL || st_gdata->rx_skb == NULL
  96              || st_gdata->is_registered[chnl_id] == false)) {
  97                 pr_err("chnl_id %d not registered, no data to send?",
  98                            chnl_id);
  99                 kfree_skb(st_gdata->rx_skb);
 100                 return;
 101         }
 102         /*
 103          * this cannot fail
 104          * this shouldn't take long
 105          * - should be just skb_queue_tail for the
 106          *   protocol stack driver
 107          */
 108         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 109                 if (unlikely
 110                         (st_gdata->list[chnl_id]->recv
 111                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 112                              != 0)) {
 113                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 114                         kfree_skb(st_gdata->rx_skb);
 115                         return;
 116                 }
 117         } else {
 118                 pr_err(" proto stack %d's ->recv null", chnl_id);
 119                 kfree_skb(st_gdata->rx_skb);
 120         }
 121         return;
 122 }
 123
 124 /*
 125  * st_reg_complete - to call registration complete callbacks
 126  * of all protocol stack drivers
 127  * This function is being called with spin lock held, protocol drivers are
 128  * only expected to complete their waits and do nothing more than that.
 129  */
 130 static void st_reg_complete(struct st_data_s *st_gdata, int err)
 131 {
 132         unsigned char i = 0;
 133         pr_info(" %s ", __func__);
 134         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 135                 if (likely(st_gdata != NULL &&
 136                         st_gdata->is_registered[i] == true &&
 137                                 st_gdata->list[i]->reg_complete_cb != NULL)) {
 138                         st_gdata->list[i]->reg_complete_cb
 139                                 (st_gdata->list[i]->priv_data, err);
 140                         pr_info("protocol %d's cb sent %d\n", i, err);
 141                         if (err) { /* cleanup registered protocol */
 142                                 st_gdata->is_registered[i] = false;
 143                                 if (st_gdata->protos_registered)
 144                                         st_gdata->protos_registered--;
 145                         }
 146                 }
 147         }
 148 }
 149
 150 static inline int st_check_data_len(struct st_data_s *st_gdata,
 151         unsigned char chnl_id, int len)
 152 {
 153         int room = skb_tailroom(st_gdata->rx_skb);
 154
 155         pr_debug("len %d room %d", len, room);
 156
 157         if (!len) {
 158                 /*
 159                  * Received packet has only packet header and
 160                  * has zero length payload. So, ask ST CORE to
 161                  * forward the packet to protocol driver (BT/FM/GPS)
 162                  */
 163                 st_send_frame(chnl_id, st_gdata);
 164
 165         } else if (len > room) {
 166                 /*
 167                  * Received packet's payload length is larger.
 168                  * We can't accommodate it in created skb.
 169                  */
 170                 pr_err("Data length is too large len %d room %d", len,
 171                            room);
 172                 kfree_skb(st_gdata->rx_skb);
 173         } else {
 174                 /*
 175                  * Packet header has non-zero payload length and
 176                  * we have enough space in created skb. Lets read
 177                  * payload data */
 178                 st_gdata->rx_state = ST_W4_DATA;
 179                 st_gdata->rx_count = len;
 180                 return len;
 181         }
 182
 183         /* Change ST state to continue to process next packet */
 184         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 185         st_gdata->rx_skb = NULL;
 186         st_gdata->rx_count = 0;
 187         st_gdata->rx_chnl = 0;
 188
 189         return 0;
 190 }
 191
 192 /*
 193  * st_wakeup_ack - internal function for action when wake-up ack
 194  *      received
 195  */
 196 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 197         unsigned char cmd)
 198 {
 199         struct sk_buff *waiting_skb;
 200         unsigned long flags = 0;
 201
 202         spin_lock_irqsave(&st_gdata->lock, flags);
 203         /*
 204          * de-Q from waitQ and Q in txQ now that the
 205          * chip is awake
 206          */
 207         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 208                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 209
 210         /* state forwarded to ST LL */
 211         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 212         spin_unlock_irqrestore(&st_gdata->lock, flags);
 213
 214         /* wake up to send the recently copied skbs from waitQ */
 215         st_tx_wakeup(st_gdata);
 216 }
 217
 218 /*
 219  * st_int_recv - ST's internal receive function.
 220  *      Decodes received RAW data and forwards to corresponding
 221  *      client drivers (Bluetooth,FM,GPS..etc).
 222  *      This can receive various types of packets,
 223  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 224  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 225  */
 226 static void st_int_recv(void *disc_data, const u8 *ptr, size_t count)
 227 {
 228         struct st_proto_s *proto;
 229         unsigned short payload_len = 0;
 230         int len = 0;
 231         unsigned char type = 0;
 232         unsigned char *plen;
 233         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 234         unsigned long flags;
 235
 236         if (st_gdata == NULL) {
 237                 pr_err(" received null from TTY ");
 238                 return;
 239         }
 240
 241         pr_debug("count %zu rx_state %ld"
 242                    "rx_count %ld", count, st_gdata->rx_state,
 243                    st_gdata->rx_count);
 244
 245         spin_lock_irqsave(&st_gdata->lock, flags);
 246         /* Decode received bytes here */
 247         while (count) {
 248                 if (st_gdata->rx_count) {
 249                         len = min_t(unsigned int, st_gdata->rx_count, count);
 250                         skb_put_data(st_gdata->rx_skb, ptr, len);
 251                         st_gdata->rx_count -= len;
 252                         count -= len;
 253                         ptr += len;
 254
 255                         if (st_gdata->rx_count)
 256                                 continue;
 257
 258                         /* Check ST RX state machine , where are we? */
 259                         switch (st_gdata->rx_state) {
 260                         /* Waiting for complete packet ? */
 261                         case ST_W4_DATA:
 262                                 pr_debug("Complete pkt received");
 263                                 /*
 264                                  * Ask ST CORE to forward
 265                                  * the packet to protocol driver
 266                                  */
 267                                 st_send_frame(st_gdata->rx_chnl, st_gdata);
 268
 269                                 st_gdata->rx_state = ST_W4_PACKET_TYPE;
 270                                 st_gdata->rx_skb = NULL;
 271                                 continue;
 272                         /* parse the header to know details */
 273                         case ST_W4_HEADER:
 274                                 proto = st_gdata->list[st_gdata->rx_chnl];
 275                                 plen =
 276                                 &st_gdata->rx_skb->data
 277                                 [proto->offset_len_in_hdr];
 278                                 pr_debug("plen pointing to %x\n", *plen);
 279                                 if (proto->len_size == 1) /* 1 byte len field */
 280                                         payload_len = *(unsigned char *)plen;
 281                                 else if (proto->len_size == 2)
 282                                         payload_len =
 283                                         __le16_to_cpu(*(unsigned short *)plen);
 284                                 else
 285                                         pr_info("%s: invalid length "
 286                                         "for id %d\n",
 287                                         __func__, proto->chnl_id);
 288                                 st_check_data_len(st_gdata, proto->chnl_id,
 289                                                 payload_len);
 290                                 pr_debug("off %d, pay len %d\n",
 291                                         proto->offset_len_in_hdr, payload_len);
 292                                 continue;
 293                         }       /* end of switch rx_state */
 294                 }
 295
 296                 /* end of if rx_count */
 297
 298                 /*
 299                  * Check first byte of packet and identify module
 300                  * owner (BT/FM/GPS)
 301                  */
 302                 switch (*ptr) {
 303                 case LL_SLEEP_IND:
 304                 case LL_SLEEP_ACK:
 305                 case LL_WAKE_UP_IND:
 306                         pr_debug("PM packet");
 307                         /*
 308                          * this takes appropriate action based on
 309                          * sleep state received --
 310                          */
 311                         st_ll_sleep_state(st_gdata, *ptr);
 312                         /*
 313                          * if WAKEUP_IND collides copy from waitq to txq
 314                          * and assume chip awake
 315                          */
 316                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 317                         if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 318                                 st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 319                         spin_lock_irqsave(&st_gdata->lock, flags);
 320
 321                         ptr++;
 322                         count--;
 323                         continue;
 324                 case LL_WAKE_UP_ACK:
 325                         pr_debug("PM packet");
 326
 327                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 328                         /* wake up ack received */
 329                         st_wakeup_ack(st_gdata, *ptr);
 330                         spin_lock_irqsave(&st_gdata->lock, flags);
 331
 332                         ptr++;
 333                         count--;
 334                         continue;
 335                         /* Unknown packet? */
 336                 default:
 337                         type = *ptr;
 338
 339                         /*
 340                          * Default case means non-HCILL packets,
 341                          * possibilities are packets for:
 342                          * (a) valid protocol -  Supported Protocols within
 343                          *     the ST_MAX_CHANNELS.
 344                          * (b) registered protocol - Checked by
 345                          *     "st_gdata->list[type] == NULL)" are supported
 346                          *     protocols only.
 347                          *  Rules out any invalid protocol and
 348                          *  unregistered protocols with channel ID < 16.
 349                          */
 350
 351                         if ((type >= ST_MAX_CHANNELS) ||
 352                                         (st_gdata->list[type] == NULL)) {
 353                                 pr_err("chip/interface misbehavior: "
 354                                                 "dropping frame starting "
 355                                                 "with 0x%02x\n", type);
 356                                 goto done;
 357                         }
 358
 359                         st_gdata->rx_skb = alloc_skb(
 360                                         st_gdata->list[type]->max_frame_size,
 361                                         GFP_ATOMIC);
 362                         if (st_gdata->rx_skb == NULL) {
 363                                 pr_err("out of memory: dropping\n");
 364                                 goto done;
 365                         }
 366
 367                         skb_reserve(st_gdata->rx_skb,
 368                                         st_gdata->list[type]->reserve);
 369                         /* next 2 required for BT only */
 370                         st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 371                         st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 372                         st_gdata->rx_chnl = *ptr;
 373                         st_gdata->rx_state = ST_W4_HEADER;
 374                         st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 375                         pr_debug("rx_count %ld\n", st_gdata->rx_count);
 376                 }
 377                 ptr++;
 378                 count--;
 379         }
 380 done:
 381         spin_unlock_irqrestore(&st_gdata->lock, flags);
 382         pr_debug("done %s", __func__);
 383         return;
 384 }
 385
 386 /*
 387  * st_int_dequeue - internal de-Q function.
 388  *      If the previous data set was not written
 389  *      completely, return that skb which has the pending data.
 390  *      In normal cases, return top of txq.
 391  */
 392 static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 393 {
 394         struct sk_buff *returning_skb;
 395
 396         pr_debug("%s", __func__);
 397         if (st_gdata->tx_skb != NULL) {
 398                 returning_skb = st_gdata->tx_skb;
 399                 st_gdata->tx_skb = NULL;
 400                 return returning_skb;
 401         }
 402         return skb_dequeue(&st_gdata->txq);
 403 }
 404
 405 /*
 406  * st_int_enqueue - internal Q-ing function.
 407  *      Will either Q the skb to txq or the tx_waitq
 408  *      depending on the ST LL state.
 409  *      If the chip is asleep, then Q it onto waitq and
 410  *      wakeup the chip.
 411  *      txq and waitq needs protection since the other contexts
 412  *      may be sending data, waking up chip.
 413  */
 414 static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 415 {
 416         unsigned long flags = 0;
 417
 418         pr_debug("%s", __func__);
 419         spin_lock_irqsave(&st_gdata->lock, flags);
 420
 421         switch (st_ll_getstate(st_gdata)) {
 422         case ST_LL_AWAKE:
 423                 pr_debug("ST LL is AWAKE, sending normally");
 424                 skb_queue_tail(&st_gdata->txq, skb);
 425                 break;
 426         case ST_LL_ASLEEP_TO_AWAKE:
 427                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 428                 break;
 429         case ST_LL_AWAKE_TO_ASLEEP:
 430                 pr_err("ST LL is illegal state(%ld),"
 431                            "purging received skb.", st_ll_getstate(st_gdata));
 432                 kfree_skb(skb);
 433                 break;
 434         case ST_LL_ASLEEP:
 435                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 436                 st_ll_wakeup(st_gdata);
 437                 break;
 438         default:
 439                 pr_err("ST LL is illegal state(%ld),"
 440                            "purging received skb.", st_ll_getstate(st_gdata));
 441                 kfree_skb(skb);
 442                 break;
 443         }
 444
 445         spin_unlock_irqrestore(&st_gdata->lock, flags);
 446         pr_debug("done %s", __func__);
 447         return;
 448 }
 449
 450 /*
 451  * internal wakeup function
 452  * called from either
 453  * - TTY layer when write's finished
 454  * - st_write (in context of the protocol stack)
 455  */
 456 static void work_fn_write_wakeup(struct work_struct *work)
 457 {
 458         struct st_data_s *st_gdata = container_of(work, struct st_data_s,
 459                         work_write_wakeup);
 460
 461         st_tx_wakeup((void *)st_gdata);
 462 }
 463 void st_tx_wakeup(struct st_data_s *st_data)
 464 {
 465         struct sk_buff *skb;
 466         unsigned long flags;    /* for irq save flags */
 467         pr_debug("%s", __func__);
 468         /* check for sending & set flag sending here */
 469         if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 470                 pr_debug("ST already sending");
 471                 /* keep sending */
 472                 set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 473                 return;
 474                 /* TX_WAKEUP will be checked in another
 475                  * context
 476                  */
 477         }
 478         do {                    /* come back if st_tx_wakeup is set */
 479                 /* woke-up to write */
 480                 clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 481                 while ((skb = st_int_dequeue(st_data))) {
 482                         int len;
 483                         spin_lock_irqsave(&st_data->lock, flags);
 484                         /* enable wake-up from TTY */
 485                         set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 486                         len = st_int_write(st_data, skb->data, skb->len);
 487                         skb_pull(skb, len);
 488                         /* if skb->len = len as expected, skb->len=0 */
 489                         if (skb->len) {
 490                                 /* would be the next skb to be sent */
 491                                 st_data->tx_skb = skb;
 492                                 spin_unlock_irqrestore(&st_data->lock, flags);
 493                                 break;
 494                         }
 495                         kfree_skb(skb);
 496                         spin_unlock_irqrestore(&st_data->lock, flags);
 497                 }
 498                 /* if wake-up is set in another context- restart sending */
 499         } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 500
 501         /* clear flag sending */
 502         clear_bit(ST_TX_SENDING, &st_data->tx_state);
 503 }
 504
 505 /********************************************************************/
 506 /* functions called from ST KIM
 507 */
 508 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 509 {
 510         seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 511                         st_gdata->protos_registered,
 512                         st_gdata->is_registered[0x04] == true ? 'R' : 'U',
 513                         st_gdata->is_registered[0x08] == true ? 'R' : 'U',
 514                         st_gdata->is_registered[0x09] == true ? 'R' : 'U');
 515 }
 516
 517 /********************************************************************/
 518 /*
 519  * functions called from protocol stack drivers
 520  * to be EXPORT-ed
 521  */
 522 long st_register(struct st_proto_s *new_proto)
 523 {
 524         struct st_data_s        *st_gdata;
 525         long err = 0;
 526         unsigned long flags = 0;
 527
 528         st_kim_ref(&st_gdata, 0);
 529         if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 530             || new_proto->reg_complete_cb == NULL) {
 531                 pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 532                 return -EINVAL;
 533         }
 534
 535         if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 536                 pr_err("chnl_id %d not supported", new_proto->chnl_id);
 537                 return -EPROTONOSUPPORT;
 538         }
 539
 540         if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 541                 pr_err("chnl_id %d already registered", new_proto->chnl_id);
 542                 return -EALREADY;
 543         }
 544
 545         /* can be from process context only */
 546         spin_lock_irqsave(&st_gdata->lock, flags);
 547
 548         if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 549                 pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 550                 /* fw download in progress */
 551
 552                 add_channel_to_table(st_gdata, new_proto);
 553                 st_gdata->protos_registered++;
 554                 new_proto->write = st_write;
 555
 556                 set_bit(ST_REG_PENDING, &st_gdata->st_state);
 557                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 558                 return -EINPROGRESS;
 559         } else if (st_gdata->protos_registered == ST_EMPTY) {
 560                 pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 561                 set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 562                 st_recv = st_kim_recv;
 563
 564                 /* enable the ST LL - to set default chip state */
 565                 st_ll_enable(st_gdata);
 566
 567                 /* release lock previously held - re-locked below */
 568                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 569
 570                 /*
 571                  * this may take a while to complete
 572                  * since it involves BT fw download
 573                  */
 574                 err = st_kim_start(st_gdata->kim_data);
 575                 if (err != 0) {
 576                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 577                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 578                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 579                                 pr_err(" KIM failure complete callback ");
 580                                 spin_lock_irqsave(&st_gdata->lock, flags);
 581                                 st_reg_complete(st_gdata, err);
 582                                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 583                                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 584                         }
 585                         return -EINVAL;
 586                 }
 587
 588                 spin_lock_irqsave(&st_gdata->lock, flags);
 589
 590                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 591                 st_recv = st_int_recv;
 592
 593                 /*
 594                  * this is where all pending registration
 595                  * are signalled to be complete by calling callback functions
 596                  */
 597                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 598                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 599                         pr_debug(" call reg complete callback ");
 600                         st_reg_complete(st_gdata, 0);
 601                 }
 602                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 603
 604                 /*
 605                  * check for already registered once more,
 606                  * since the above check is old
 607                  */
 608                 if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 609                         pr_err(" proto %d already registered ",
 610                                    new_proto->chnl_id);
 611                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 612                         return -EALREADY;
 613                 }
 614
 615                 add_channel_to_table(st_gdata, new_proto);
 616                 st_gdata->protos_registered++;
 617                 new_proto->write = st_write;
 618                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 619                 return err;
 620         }
 621         /* if fw is already downloaded & new stack registers protocol */
 622         else {
 623                 add_channel_to_table(st_gdata, new_proto);
 624                 st_gdata->protos_registered++;
 625                 new_proto->write = st_write;
 626
 627                 /* lock already held before entering else */
 628                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 629                 return err;
 630         }
 631 }
 632 EXPORT_SYMBOL_GPL(st_register);
 633
 634 /*
 635  * to unregister a protocol -
 636  * to be called from protocol stack driver
 637  */
 638 long st_unregister(struct st_proto_s *proto)
 639 {
 640         long err = 0;
 641         unsigned long flags = 0;
 642         struct st_data_s        *st_gdata;
 643
 644         pr_debug("%s: %d ", __func__, proto->chnl_id);
 645
 646         st_kim_ref(&st_gdata, 0);
 647         if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 648                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 649                 return -EPROTONOSUPPORT;
 650         }
 651
 652         spin_lock_irqsave(&st_gdata->lock, flags);
 653
 654         if (st_gdata->is_registered[proto->chnl_id] == false) {
 655                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 656                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 657                 return -EPROTONOSUPPORT;
 658         }
 659
 660         if (st_gdata->protos_registered)
 661                 st_gdata->protos_registered--;
 662
 663         remove_channel_from_table(st_gdata, proto);
 664         spin_unlock_irqrestore(&st_gdata->lock, flags);
 665
 666         if ((st_gdata->protos_registered == ST_EMPTY) &&
 667             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 668                 pr_info(" all chnl_ids unregistered ");
 669
 670                 /* stop traffic on tty */
 671                 if (st_gdata->tty) {
 672                         tty_ldisc_flush(st_gdata->tty);
 673                         stop_tty(st_gdata->tty);
 674                 }
 675
 676                 /* all chnl_ids now unregistered */
 677                 st_kim_stop(st_gdata->kim_data);
 678                 /* disable ST LL */
 679                 st_ll_disable(st_gdata);
 680         }
 681         return err;
 682 }
 683
 684 /*
 685  * called in protocol stack drivers
 686  * via the write function pointer
 687  */
 688 long st_write(struct sk_buff *skb)
 689 {
 690         struct st_data_s *st_gdata;
 691         long len;
 692
 693         st_kim_ref(&st_gdata, 0);
 694         if (unlikely(skb == NULL || st_gdata == NULL
 695                 || st_gdata->tty == NULL)) {
 696                 pr_err("data/tty unavailable to perform write");
 697                 return -EINVAL;
 698         }
 699
 700         pr_debug("%d to be written", skb->len);
 701         len = skb->len;
 702
 703         /* st_ll to decide where to enqueue the skb */
 704         st_int_enqueue(st_gdata, skb);
 705         /* wake up */
 706         st_tx_wakeup(st_gdata);
 707
 708         /* return number of bytes written */
 709         return len;
 710 }
 711
 712 /* for protocols making use of shared transport */
 713 EXPORT_SYMBOL_GPL(st_unregister);
 714
 715 /********************************************************************/
 716 /*
 717  * functions called from TTY layer
 718  */
 719 static int st_tty_open(struct tty_struct *tty)
 720 {
 721         struct st_data_s *st_gdata;
 722         pr_info("%s ", __func__);
 723
 724         st_kim_ref(&st_gdata, 0);
 725         st_gdata->tty = tty;
 726         tty->disc_data = st_gdata;
 727
 728         /* don't do an wakeup for now */
 729         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 730
 731         /* mem already allocated
 732          */
 733         tty->receive_room = 65536;
 734         /* Flush any pending characters in the driver and discipline. */
 735         tty_ldisc_flush(tty);
 736         tty_driver_flush_buffer(tty);
 737         /*
 738          * signal to UIM via KIM that -
 739          * installation of N_TI_WL ldisc is complete
 740          */
 741         st_kim_complete(st_gdata->kim_data);
 742         pr_debug("done %s", __func__);
 743
 744         return 0;
 745 }
 746
 747 static void st_tty_close(struct tty_struct *tty)
 748 {
 749         unsigned char i;
 750         unsigned long flags;
 751         struct  st_data_s *st_gdata = tty->disc_data;
 752
 753         pr_info("%s ", __func__);
 754
 755         /*
 756          * TODO:
 757          * if a protocol has been registered & line discipline
 758          * un-installed for some reason - what should be done ?
 759          */
 760         spin_lock_irqsave(&st_gdata->lock, flags);
 761         for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 762                 if (st_gdata->is_registered[i] == true)
 763                         pr_err("%d not un-registered", i);
 764                 st_gdata->list[i] = NULL;
 765                 st_gdata->is_registered[i] = false;
 766         }
 767         st_gdata->protos_registered = 0;
 768         spin_unlock_irqrestore(&st_gdata->lock, flags);
 769         /*
 770          * signal to UIM via KIM that -
 771          * N_TI_WL ldisc is un-installed
 772          */
 773         st_kim_complete(st_gdata->kim_data);
 774         st_gdata->tty = NULL;
 775         /* Flush any pending characters in the driver and discipline. */
 776         tty_ldisc_flush(tty);
 777         tty_driver_flush_buffer(tty);
 778
 779         spin_lock_irqsave(&st_gdata->lock, flags);
 780         /* empty out txq and tx_waitq */
 781         skb_queue_purge(&st_gdata->txq);
 782         skb_queue_purge(&st_gdata->tx_waitq);
 783         /* reset the TTY Rx states of ST */
 784         st_gdata->rx_count = 0;
 785         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 786         kfree_skb(st_gdata->rx_skb);
 787         st_gdata->rx_skb = NULL;
 788         spin_unlock_irqrestore(&st_gdata->lock, flags);
 789
 790         pr_debug("%s: done ", __func__);
 791 }
 792
 793 static void st_tty_receive(struct tty_struct *tty, const u8 *data,
 794                            const u8 *tty_flags, size_t count)
 795 {
 796 #ifdef VERBOSE
 797         print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 798                 16, 1, data, count, 0);
 799 #endif
 800
 801         /*
 802          * if fw download is in progress then route incoming data
 803          * to KIM for validation
 804          */
 805         st_recv(tty->disc_data, data, count);
 806         pr_debug("done %s", __func__);
 807 }
 808
 809 /*
 810  * wake-up function called in from the TTY layer
 811  * inside the internal wakeup function will be called
 812  */
 813 static void st_tty_wakeup(struct tty_struct *tty)
 814 {
 815         struct  st_data_s *st_gdata = tty->disc_data;
 816         pr_debug("%s ", __func__);
 817         /* don't do an wakeup for now */
 818         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 819
 820         /*
 821          * schedule the internal wakeup instead of calling directly to
 822          * avoid lockup (port->lock needed in tty->ops->write is
 823          * already taken here
 824          */
 825         schedule_work(&st_gdata->work_write_wakeup);
 826 }
 827
 828 static void st_tty_flush_buffer(struct tty_struct *tty)
 829 {
 830         struct  st_data_s *st_gdata = tty->disc_data;
 831         pr_debug("%s ", __func__);
 832
 833         kfree_skb(st_gdata->tx_skb);
 834         st_gdata->tx_skb = NULL;
 835
 836         tty_driver_flush_buffer(tty);
 837         return;
 838 }
 839
 840 static struct tty_ldisc_ops st_ldisc_ops = {
 841         .num = N_TI_WL,
 842         .name = "n_st",
 843         .open = st_tty_open,
 844         .close = st_tty_close,
 845         .receive_buf = st_tty_receive,
 846         .write_wakeup = st_tty_wakeup,
 847         .flush_buffer = st_tty_flush_buffer,
 848         .owner = THIS_MODULE
 849 };
 850
 851 /********************************************************************/
 852 int st_core_init(struct st_data_s **core_data)
 853 {
 854         struct st_data_s *st_gdata;
 855         long err;
 856
 857         err = tty_register_ldisc(&st_ldisc_ops);
 858         if (err) {
 859                 pr_err("error registering %d line discipline %ld",
 860                            N_TI_WL, err);
 861                 return err;
 862         }
 863         pr_debug("registered n_shared line discipline");
 864
 865         st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
 866         if (!st_gdata) {
 867                 pr_err("memory allocation failed");
 868                 err = -ENOMEM;
 869                 goto err_unreg_ldisc;
 870         }
 871
 872         /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 873          * will be pushed in this queue for actual transmission.
 874          */
 875         skb_queue_head_init(&st_gdata->txq);
 876         skb_queue_head_init(&st_gdata->tx_waitq);
 877
 878         /* Locking used in st_int_enqueue() to avoid multiple execution */
 879         spin_lock_init(&st_gdata->lock);
 880
 881         err = st_ll_init(st_gdata);
 882         if (err) {
 883                 pr_err("error during st_ll initialization(%ld)", err);
 884                 goto err_free_gdata;
 885         }
 886
 887         INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
 888
 889         *core_data = st_gdata;
 890         return 0;
 891 err_free_gdata:
 892         kfree(st_gdata);
 893 err_unreg_ldisc:
 894         tty_unregister_ldisc(&st_ldisc_ops);
 895         return err;
 896 }
 897
 898 void st_core_exit(struct st_data_s *st_gdata)
 899 {
 900         long err;
 901         /* internal module cleanup */
 902         err = st_ll_deinit(st_gdata);
 903         if (err)
 904                 pr_err("error during deinit of ST LL %ld", err);
 905
 906         if (st_gdata != NULL) {
 907                 /* Free ST Tx Qs and skbs */
 908                 skb_queue_purge(&st_gdata->txq);
 909                 skb_queue_purge(&st_gdata->tx_waitq);
 910                 kfree_skb(st_gdata->rx_skb);
 911                 kfree_skb(st_gdata->tx_skb);
 912                 /* TTY ldisc cleanup */
 913                 tty_unregister_ldisc(&st_ldisc_ops);
 914                 /* free the global data pointer */
 915                 kfree(st_gdata);
 916         }
 917 }