drivers/thunderbolt/path.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt Cactus Ridge driver - path/tunnel functionality
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/errno.h>
  10 #include <linux/delay.h>
  11 #include <linux/ktime.h>
  12
  13 #include "tb.h"
  14
  15
  16 static void tb_dump_hop(struct tb_port *port, struct tb_regs_hop *hop)
  17 {
  18         tb_port_dbg(port, " Hop through port %d to hop %d (%s)\n",
  19                     hop->out_port, hop->next_hop,
  20                     hop->enable ? "enabled" : "disabled");
  21         tb_port_dbg(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
  22                     hop->weight, hop->priority,
  23                     hop->initial_credits, hop->drop_packages);
  24         tb_port_dbg(port, "   Counter enabled: %d Counter index: %d\n",
  25                     hop->counter_enable, hop->counter);
  26         tb_port_dbg(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
  27                     hop->ingress_fc, hop->egress_fc,
  28                     hop->ingress_shared_buffer, hop->egress_shared_buffer);
  29         tb_port_dbg(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
  30                     hop->unknown1, hop->unknown2, hop->unknown3);
  31 }
  32
  33 /**
  34  * tb_path_alloc() - allocate a thunderbolt path between two ports
  35  * @tb: Domain pointer
  36  * @src: Source port of the path
  37  * @src_hopid: HopID used for the first ingress port in the path
  38  * @dst: Destination port of the path
  39  * @dst_hopid: HopID used for the last egress port in the path
  40  * @link_nr: Preferred link if there are dual links on the path
  41  * @name: Name of the path
  42  *
  43  * Creates path between two ports starting with given @src_hopid. Reserves
  44  * HopIDs for each port (they can be different from @src_hopid depending on
  45  * how many HopIDs each port already have reserved). If there are dual
  46  * links on the path, prioritizes using @link_nr.
  47  *
  48  * Return: Returns a tb_path on success or NULL on failure.
  49  */
  50 struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
  51                               struct tb_port *dst, int dst_hopid, int link_nr,
  52                               const char *name)
  53 {
  54         struct tb_port *in_port, *out_port;
  55         int in_hopid, out_hopid;
  56         struct tb_path *path;
  57         size_t num_hops;
  58         int i, ret;
  59
  60         path = kzalloc(sizeof(*path), GFP_KERNEL);
  61         if (!path)
  62                 return NULL;
  63
  64         /*
  65          * Number of hops on a path is the distance between the two
  66          * switches plus the source adapter port.
  67          */
  68         num_hops = abs(tb_route_length(tb_route(src->sw)) -
  69                        tb_route_length(tb_route(dst->sw))) + 1;
  70
  71         path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
  72         if (!path->hops) {
  73                 kfree(path);
  74                 return NULL;
  75         }
  76
  77         in_hopid = src_hopid;
  78         out_port = NULL;
  79
  80         for (i = 0; i < num_hops; i++) {
  81                 in_port = tb_next_port_on_path(src, dst, out_port);
  82                 if (!in_port)
  83                         goto err;
  84
  85                 if (in_port->dual_link_port && in_port->link_nr != link_nr)
  86                         in_port = in_port->dual_link_port;
  87
  88                 ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
  89                 if (ret < 0)
  90                         goto err;
  91                 in_hopid = ret;
  92
  93                 out_port = tb_next_port_on_path(src, dst, in_port);
  94                 if (!out_port)
  95                         goto err;
  96
  97                 if (out_port->dual_link_port && out_port->link_nr != link_nr)
  98                         out_port = out_port->dual_link_port;
  99
 100                 if (i == num_hops - 1)
 101                         ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
 102                                                       dst_hopid);
 103                 else
 104                         ret = tb_port_alloc_out_hopid(out_port, -1, -1);
 105
 106                 if (ret < 0)
 107                         goto err;
 108                 out_hopid = ret;
 109
 110                 path->hops[i].in_hop_index = in_hopid;
 111                 path->hops[i].in_port = in_port;
 112                 path->hops[i].in_counter_index = -1;
 113                 path->hops[i].out_port = out_port;
 114                 path->hops[i].next_hop_index = out_hopid;
 115
 116                 in_hopid = out_hopid;
 117         }
 118
 119         path->tb = tb;
 120         path->path_length = num_hops;
 121         path->name = name;
 122
 123         return path;
 124
 125 err:
 126         tb_path_free(path);
 127         return NULL;
 128 }
 129
 130 /**
 131  * tb_path_free() - free a deactivated path
 132  */
 133 void tb_path_free(struct tb_path *path)
 134 {
 135         int i;
 136
 137         if (path->activated) {
 138                 tb_WARN(path->tb, "trying to free an activated path\n")
 139                 return;
 140         }
 141
 142         for (i = 0; i < path->path_length; i++) {
 143                 const struct tb_path_hop *hop = &path->hops[i];
 144
 145                 if (hop->in_port)
 146                         tb_port_release_in_hopid(hop->in_port,
 147                                                  hop->in_hop_index);
 148                 if (hop->out_port)
 149                         tb_port_release_out_hopid(hop->out_port,
 150                                                   hop->next_hop_index);
 151         }
 152
 153         kfree(path->hops);
 154         kfree(path);
 155 }
 156
 157 static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
 158 {
 159         int i, res;
 160         for (i = first_hop; i < path->path_length; i++) {
 161                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 162                                               -path->nfc_credits);
 163                 if (res)
 164                         tb_port_warn(path->hops[i].in_port,
 165                                      "nfc credits deallocation failed for hop %d\n",
 166                                      i);
 167         }
 168 }
 169
 170 static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index)
 171 {
 172         struct tb_regs_hop hop;
 173         ktime_t timeout;
 174         int ret;
 175
 176         /* Disable the path */
 177         ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 178         if (ret)
 179                 return ret;
 180
 181         /* Already disabled */
 182         if (!hop.enable)
 183                 return 0;
 184
 185         hop.enable = 0;
 186
 187         ret = tb_port_write(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 188         if (ret)
 189                 return ret;
 190
 191         /* Wait until it is drained */
 192         timeout = ktime_add_ms(ktime_get(), 500);
 193         do {
 194                 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 195                 if (ret)
 196                         return ret;
 197
 198                 if (!hop.pending)
 199                         return 0;
 200
 201                 usleep_range(10, 20);
 202         } while (ktime_before(ktime_get(), timeout));
 203
 204         return -ETIMEDOUT;
 205 }
 206
 207 static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
 208 {
 209         int i, res;
 210
 211         for (i = first_hop; i < path->path_length; i++) {
 212                 res = __tb_path_deactivate_hop(path->hops[i].in_port,
 213                                                path->hops[i].in_hop_index);
 214                 if (res && res != -ENODEV)
 215                         tb_port_warn(path->hops[i].in_port,
 216                                      "hop deactivation failed for hop %d, index %d\n",
 217                                      i, path->hops[i].in_hop_index);
 218         }
 219 }
 220
 221 void tb_path_deactivate(struct tb_path *path)
 222 {
 223         if (!path->activated) {
 224                 tb_WARN(path->tb, "trying to deactivate an inactive path\n");
 225                 return;
 226         }
 227         tb_dbg(path->tb,
 228                "deactivating %s path from %llx:%x to %llx:%x\n",
 229                path->name, tb_route(path->hops[0].in_port->sw),
 230                path->hops[0].in_port->port,
 231                tb_route(path->hops[path->path_length - 1].out_port->sw),
 232                path->hops[path->path_length - 1].out_port->port);
 233         __tb_path_deactivate_hops(path, 0);
 234         __tb_path_deallocate_nfc(path, 0);
 235         path->activated = false;
 236 }
 237
 238 /**
 239  * tb_path_activate() - activate a path
 240  *
 241  * Activate a path starting with the last hop and iterating backwards. The
 242  * caller must fill path->hops before calling tb_path_activate().
 243  *
 244  * Return: Returns 0 on success or an error code on failure.
 245  */
 246 int tb_path_activate(struct tb_path *path)
 247 {
 248         int i, res;
 249         enum tb_path_port out_mask, in_mask;
 250         if (path->activated) {
 251                 tb_WARN(path->tb, "trying to activate already activated path\n");
 252                 return -EINVAL;
 253         }
 254
 255         tb_dbg(path->tb,
 256                "activating %s path from %llx:%x to %llx:%x\n",
 257                path->name, tb_route(path->hops[0].in_port->sw),
 258                path->hops[0].in_port->port,
 259                tb_route(path->hops[path->path_length - 1].out_port->sw),
 260                path->hops[path->path_length - 1].out_port->port);
 261
 262         /* Clear counters. */
 263         for (i = path->path_length - 1; i >= 0; i--) {
 264                 if (path->hops[i].in_counter_index == -1)
 265                         continue;
 266                 res = tb_port_clear_counter(path->hops[i].in_port,
 267                                             path->hops[i].in_counter_index);
 268                 if (res)
 269                         goto err;
 270         }
 271
 272         /* Add non flow controlled credits. */
 273         for (i = path->path_length - 1; i >= 0; i--) {
 274                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 275                                               path->nfc_credits);
 276                 if (res) {
 277                         __tb_path_deallocate_nfc(path, i);
 278                         goto err;
 279                 }
 280         }
 281
 282         /* Activate hops. */
 283         for (i = path->path_length - 1; i >= 0; i--) {
 284                 struct tb_regs_hop hop = { 0 };
 285
 286                 /*
 287                  * We do (currently) not tear down paths setup by the firmeware.
 288                  * If a firmware device is unplugged and plugged in again then
 289                  * it can happen that we reuse some of the hops from the (now
 290                  * defunct) firmeware path. This causes the hotplug operation to
 291                  * fail (the pci device does not show up). Clearing the hop
 292                  * before overwriting it fixes the problem.
 293                  *
 294                  * Should be removed once we discover and tear down firmeware
 295                  * paths.
 296                  */
 297                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
 298                                     2 * path->hops[i].in_hop_index, 2);
 299                 if (res) {
 300                         __tb_path_deactivate_hops(path, i);
 301                         __tb_path_deallocate_nfc(path, 0);
 302                         goto err;
 303                 }
 304
 305                 /* dword 0 */
 306                 hop.next_hop = path->hops[i].next_hop_index;
 307                 hop.out_port = path->hops[i].out_port->port;
 308                 /* TODO: figure out why these are good values */
 309                 hop.initial_credits = (i == path->path_length - 1) ? 16 : 7;
 310                 hop.unknown1 = 0;
 311                 hop.enable = 1;
 312
 313                 /* dword 1 */
 314                 out_mask = (i == path->path_length - 1) ?
 315                                 TB_PATH_DESTINATION : TB_PATH_INTERNAL;
 316                 in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
 317                 hop.weight = path->weight;
 318                 hop.unknown2 = 0;
 319                 hop.priority = path->priority;
 320                 hop.drop_packages = path->drop_packages;
 321                 hop.counter = path->hops[i].in_counter_index;
 322                 hop.counter_enable = path->hops[i].in_counter_index != -1;
 323                 hop.ingress_fc = path->ingress_fc_enable & in_mask;
 324                 hop.egress_fc = path->egress_fc_enable & out_mask;
 325                 hop.ingress_shared_buffer = path->ingress_shared_buffer
 326                                             & in_mask;
 327                 hop.egress_shared_buffer = path->egress_shared_buffer
 328                                             & out_mask;
 329                 hop.unknown3 = 0;
 330
 331                 tb_port_info(path->hops[i].in_port, "Writing hop %d, index %d",
 332                              i, path->hops[i].in_hop_index);
 333                 tb_dump_hop(path->hops[i].in_port, &hop);
 334                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
 335                                     2 * path->hops[i].in_hop_index, 2);
 336                 if (res) {
 337                         __tb_path_deactivate_hops(path, i);
 338                         __tb_path_deallocate_nfc(path, 0);
 339                         goto err;
 340                 }
 341         }
 342         path->activated = true;
 343         tb_info(path->tb, "path activation complete\n");
 344         return 0;
 345 err:
 346         tb_WARN(path->tb, "path activation failed\n");
 347         return res;
 348 }
 349
 350 /**
 351  * tb_path_is_invalid() - check whether any ports on the path are invalid
 352  *
 353  * Return: Returns true if the path is invalid, false otherwise.
 354  */
 355 bool tb_path_is_invalid(struct tb_path *path)
 356 {
 357         int i = 0;
 358         for (i = 0; i < path->path_length; i++) {
 359                 if (path->hops[i].in_port->sw->is_unplugged)
 360                         return true;
 361                 if (path->hops[i].out_port->sw->is_unplugged)
 362                         return true;
 363         }
 364         return false;
 365 }