root/drivers/thunderbolt/path.c

DEFINITIONS

1. tb_dump_hop
2. tb_path_find_dst_port
3. tb_path_find_src_hopid
4. tb_path_discover
5. tb_path_alloc
6. tb_path_free
7. __tb_path_deallocate_nfc
8. __tb_path_deactivate_hop
9. __tb_path_deactivate_hops
10. tb_path_deactivate
11. tb_path_activate
12. tb_path_is_invalid

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt driver - path/tunnel functionality
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  * Copyright (C) 2019, Intel Corporation
   7  */
   8 
   9 #include <linux/slab.h>
  10 #include <linux/errno.h>
  11 #include <linux/delay.h>
  12 #include <linux/ktime.h>
  13 
  14 #include "tb.h"
  15 
  16 static void tb_dump_hop(const struct tb_path_hop *hop, const struct tb_regs_hop *regs)
  17 {
  18         const struct tb_port *port = hop->in_port;
  19 
  20         tb_port_dbg(port, " In HopID: %d => Out port: %d Out HopID: %d\n",
  21                     hop->in_hop_index, regs->out_port, regs->next_hop);
  22         tb_port_dbg(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
  23                     regs->weight, regs->priority,
  24                     regs->initial_credits, regs->drop_packages);
  25         tb_port_dbg(port, "   Counter enabled: %d Counter index: %d\n",
  26                     regs->counter_enable, regs->counter);
  27         tb_port_dbg(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
  28                     regs->ingress_fc, regs->egress_fc,
  29                     regs->ingress_shared_buffer, regs->egress_shared_buffer);
  30         tb_port_dbg(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
  31                     regs->unknown1, regs->unknown2, regs->unknown3);
  32 }
  33 
  34 static struct tb_port *tb_path_find_dst_port(struct tb_port *src, int src_hopid,
  35                                              int dst_hopid)
  36 {
  37         struct tb_port *port, *out_port = NULL;
  38         struct tb_regs_hop hop;
  39         struct tb_switch *sw;
  40         int i, ret, hopid;
  41 
  42         hopid = src_hopid;
  43         port = src;
  44 
  45         for (i = 0; port && i < TB_PATH_MAX_HOPS; i++) {
  46                 sw = port->sw;
  47 
  48                 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hopid, 2);
  49                 if (ret) {
  50                         tb_port_warn(port, "failed to read path at %d\n", hopid);
  51                         return NULL;
  52                 }
  53 
  54                 if (!hop.enable)
  55                         return NULL;
  56 
  57                 out_port = &sw->ports[hop.out_port];
  58                 hopid = hop.next_hop;
  59                 port = out_port->remote;
  60         }
  61 
  62         return out_port && hopid == dst_hopid ? out_port : NULL;
  63 }
  64 
  65 static int tb_path_find_src_hopid(struct tb_port *src,
  66         const struct tb_port *dst, int dst_hopid)
  67 {
  68         struct tb_port *out;
  69         int i;
  70 
  71         for (i = TB_PATH_MIN_HOPID; i <= src->config.max_in_hop_id; i++) {
  72                 out = tb_path_find_dst_port(src, i, dst_hopid);
  73                 if (out == dst)
  74                         return i;
  75         }
  76 
  77         return 0;
  78 }
  79 
  80 /**
  81  * tb_path_discover() - Discover a path
  82  * @src: First input port of a path
  83  * @src_hopid: Starting HopID of a path (%-1 if don't care)
  84  * @dst: Expected destination port of the path (%NULL if don't care)
  85  * @dst_hopid: HopID to the @dst (%-1 if don't care)
  86  * @last: Last port is filled here if not %NULL
  87  * @name: Name of the path
  88  *
  89  * Follows a path starting from @src and @src_hopid to the last output
  90  * port of the path. Allocates HopIDs for the visited ports. Call
  91  * tb_path_free() to release the path and allocated HopIDs when the path
  92  * is not needed anymore.
  93  *
  94  * Note function discovers also incomplete paths so caller should check
  95  * that the @dst port is the expected one. If it is not, the path can be
  96  * cleaned up by calling tb_path_deactivate() before tb_path_free().
  97  *
  98  * Return: Discovered path on success, %NULL in case of failure
  99  */
 100 struct tb_path *tb_path_discover(struct tb_port *src, int src_hopid,
 101                                  struct tb_port *dst, int dst_hopid,
 102                                  struct tb_port **last, const char *name)
 103 {
 104         struct tb_port *out_port;
 105         struct tb_regs_hop hop;
 106         struct tb_path *path;
 107         struct tb_switch *sw;
 108         struct tb_port *p;
 109         size_t num_hops;
 110         int ret, i, h;
 111 
 112         if (src_hopid < 0 && dst) {
 113                 /*
 114                  * For incomplete paths the intermediate HopID can be
 115                  * different from the one used by the protocol adapter
 116                  * so in that case find a path that ends on @dst with
 117                  * matching @dst_hopid. That should give us the correct
 118                  * HopID for the @src.
 119                  */
 120                 src_hopid = tb_path_find_src_hopid(src, dst, dst_hopid);
 121                 if (!src_hopid)
 122                         return NULL;
 123         }
 124 
 125         p = src;
 126         h = src_hopid;
 127         num_hops = 0;
 128 
 129         for (i = 0; p && i < TB_PATH_MAX_HOPS; i++) {
 130                 sw = p->sw;
 131 
 132                 ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
 133                 if (ret) {
 134                         tb_port_warn(p, "failed to read path at %d\n", h);
 135                         return NULL;
 136                 }
 137 
 138                 /* If the hop is not enabled we got an incomplete path */
 139                 if (!hop.enable)
 140                         break;
 141 
 142                 out_port = &sw->ports[hop.out_port];
 143                 if (last)
 144                         *last = out_port;
 145 
 146                 h = hop.next_hop;
 147                 p = out_port->remote;
 148                 num_hops++;
 149         }
 150 
 151         path = kzalloc(sizeof(*path), GFP_KERNEL);
 152         if (!path)
 153                 return NULL;
 154 
 155         path->name = name;
 156         path->tb = src->sw->tb;
 157         path->path_length = num_hops;
 158         path->activated = true;
 159 
 160         path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
 161         if (!path->hops) {
 162                 kfree(path);
 163                 return NULL;
 164         }
 165 
 166         p = src;
 167         h = src_hopid;
 168 
 169         for (i = 0; i < num_hops; i++) {
 170                 int next_hop;
 171 
 172                 sw = p->sw;
 173 
 174                 ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
 175                 if (ret) {
 176                         tb_port_warn(p, "failed to read path at %d\n", h);
 177                         goto err;
 178                 }
 179 
 180                 if (tb_port_alloc_in_hopid(p, h, h) < 0)
 181                         goto err;
 182 
 183                 out_port = &sw->ports[hop.out_port];
 184                 next_hop = hop.next_hop;
 185 
 186                 if (tb_port_alloc_out_hopid(out_port, next_hop, next_hop) < 0) {
 187                         tb_port_release_in_hopid(p, h);
 188                         goto err;
 189                 }
 190 
 191                 path->hops[i].in_port = p;
 192                 path->hops[i].in_hop_index = h;
 193                 path->hops[i].in_counter_index = -1;
 194                 path->hops[i].out_port = out_port;
 195                 path->hops[i].next_hop_index = next_hop;
 196 
 197                 h = next_hop;
 198                 p = out_port->remote;
 199         }
 200 
 201         return path;
 202 
 203 err:
 204         tb_port_warn(src, "failed to discover path starting at HopID %d\n",
 205                      src_hopid);
 206         tb_path_free(path);
 207         return NULL;
 208 }
 209 
 210 /**
 211  * tb_path_alloc() - allocate a thunderbolt path between two ports
 212  * @tb: Domain pointer
 213  * @src: Source port of the path
 214  * @src_hopid: HopID used for the first ingress port in the path
 215  * @dst: Destination port of the path
 216  * @dst_hopid: HopID used for the last egress port in the path
 217  * @link_nr: Preferred link if there are dual links on the path
 218  * @name: Name of the path
 219  *
 220  * Creates path between two ports starting with given @src_hopid. Reserves
 221  * HopIDs for each port (they can be different from @src_hopid depending on
 222  * how many HopIDs each port already have reserved). If there are dual
 223  * links on the path, prioritizes using @link_nr.
 224  *
 225  * Return: Returns a tb_path on success or NULL on failure.
 226  */
 227 struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
 228                               struct tb_port *dst, int dst_hopid, int link_nr,
 229                               const char *name)
 230 {
 231         struct tb_port *in_port, *out_port;
 232         int in_hopid, out_hopid;
 233         struct tb_path *path;
 234         size_t num_hops;
 235         int i, ret;
 236 
 237         path = kzalloc(sizeof(*path), GFP_KERNEL);
 238         if (!path)
 239                 return NULL;
 240 
 241         /*
 242          * Number of hops on a path is the distance between the two
 243          * switches plus the source adapter port.
 244          */
 245         num_hops = abs(tb_route_length(tb_route(src->sw)) -
 246                        tb_route_length(tb_route(dst->sw))) + 1;
 247 
 248         path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
 249         if (!path->hops) {
 250                 kfree(path);
 251                 return NULL;
 252         }
 253 
 254         in_hopid = src_hopid;
 255         out_port = NULL;
 256 
 257         for (i = 0; i < num_hops; i++) {
 258                 in_port = tb_next_port_on_path(src, dst, out_port);
 259                 if (!in_port)
 260                         goto err;
 261 
 262                 if (in_port->dual_link_port && in_port->link_nr != link_nr)
 263                         in_port = in_port->dual_link_port;
 264 
 265                 ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
 266                 if (ret < 0)
 267                         goto err;
 268                 in_hopid = ret;
 269 
 270                 out_port = tb_next_port_on_path(src, dst, in_port);
 271                 if (!out_port)
 272                         goto err;
 273 
 274                 if (out_port->dual_link_port && out_port->link_nr != link_nr)
 275                         out_port = out_port->dual_link_port;
 276 
 277                 if (i == num_hops - 1)
 278                         ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
 279                                                       dst_hopid);
 280                 else
 281                         ret = tb_port_alloc_out_hopid(out_port, -1, -1);
 282 
 283                 if (ret < 0)
 284                         goto err;
 285                 out_hopid = ret;
 286 
 287                 path->hops[i].in_hop_index = in_hopid;
 288                 path->hops[i].in_port = in_port;
 289                 path->hops[i].in_counter_index = -1;
 290                 path->hops[i].out_port = out_port;
 291                 path->hops[i].next_hop_index = out_hopid;
 292 
 293                 in_hopid = out_hopid;
 294         }
 295 
 296         path->tb = tb;
 297         path->path_length = num_hops;
 298         path->name = name;
 299 
 300         return path;
 301 
 302 err:
 303         tb_path_free(path);
 304         return NULL;
 305 }
 306 
 307 /**
 308  * tb_path_free() - free a path
 309  * @path: Path to free
 310  *
 311  * Frees a path. The path does not need to be deactivated.
 312  */
 313 void tb_path_free(struct tb_path *path)
 314 {
 315         int i;
 316 
 317         for (i = 0; i < path->path_length; i++) {
 318                 const struct tb_path_hop *hop = &path->hops[i];
 319 
 320                 if (hop->in_port)
 321                         tb_port_release_in_hopid(hop->in_port,
 322                                                  hop->in_hop_index);
 323                 if (hop->out_port)
 324                         tb_port_release_out_hopid(hop->out_port,
 325                                                   hop->next_hop_index);
 326         }
 327 
 328         kfree(path->hops);
 329         kfree(path);
 330 }
 331 
 332 static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
 333 {
 334         int i, res;
 335         for (i = first_hop; i < path->path_length; i++) {
 336                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 337                                               -path->nfc_credits);
 338                 if (res)
 339                         tb_port_warn(path->hops[i].in_port,
 340                                      "nfc credits deallocation failed for hop %d\n",
 341                                      i);
 342         }
 343 }
 344 
 345 static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index,
 346                                     bool clear_fc)
 347 {
 348         struct tb_regs_hop hop;
 349         ktime_t timeout;
 350         int ret;
 351 
 352         /* Disable the path */
 353         ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 354         if (ret)
 355                 return ret;
 356 
 357         /* Already disabled */
 358         if (!hop.enable)
 359                 return 0;
 360 
 361         hop.enable = 0;
 362 
 363         ret = tb_port_write(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 364         if (ret)
 365                 return ret;
 366 
 367         /* Wait until it is drained */
 368         timeout = ktime_add_ms(ktime_get(), 500);
 369         do {
 370                 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 371                 if (ret)
 372                         return ret;
 373 
 374                 if (!hop.pending) {
 375                         if (clear_fc) {
 376                                 /* Clear flow control */
 377                                 hop.ingress_fc = 0;
 378                                 hop.egress_fc = 0;
 379                                 hop.ingress_shared_buffer = 0;
 380                                 hop.egress_shared_buffer = 0;
 381 
 382                                 return tb_port_write(port, &hop, TB_CFG_HOPS,
 383                                                      2 * hop_index, 2);
 384                         }
 385 
 386                         return 0;
 387                 }
 388 
 389                 usleep_range(10, 20);
 390         } while (ktime_before(ktime_get(), timeout));
 391 
 392         return -ETIMEDOUT;
 393 }
 394 
 395 static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
 396 {
 397         int i, res;
 398 
 399         for (i = first_hop; i < path->path_length; i++) {
 400                 res = __tb_path_deactivate_hop(path->hops[i].in_port,
 401                                                path->hops[i].in_hop_index,
 402                                                path->clear_fc);
 403                 if (res && res != -ENODEV)
 404                         tb_port_warn(path->hops[i].in_port,
 405                                      "hop deactivation failed for hop %d, index %d\n",
 406                                      i, path->hops[i].in_hop_index);
 407         }
 408 }
 409 
 410 void tb_path_deactivate(struct tb_path *path)
 411 {
 412         if (!path->activated) {
 413                 tb_WARN(path->tb, "trying to deactivate an inactive path\n");
 414                 return;
 415         }
 416         tb_dbg(path->tb,
 417                "deactivating %s path from %llx:%x to %llx:%x\n",
 418                path->name, tb_route(path->hops[0].in_port->sw),
 419                path->hops[0].in_port->port,
 420                tb_route(path->hops[path->path_length - 1].out_port->sw),
 421                path->hops[path->path_length - 1].out_port->port);
 422         __tb_path_deactivate_hops(path, 0);
 423         __tb_path_deallocate_nfc(path, 0);
 424         path->activated = false;
 425 }
 426 
 427 /**
 428  * tb_path_activate() - activate a path
 429  *
 430  * Activate a path starting with the last hop and iterating backwards. The
 431  * caller must fill path->hops before calling tb_path_activate().
 432  *
 433  * Return: Returns 0 on success or an error code on failure.
 434  */
 435 int tb_path_activate(struct tb_path *path)
 436 {
 437         int i, res;
 438         enum tb_path_port out_mask, in_mask;
 439         if (path->activated) {
 440                 tb_WARN(path->tb, "trying to activate already activated path\n");
 441                 return -EINVAL;
 442         }
 443 
 444         tb_dbg(path->tb,
 445                "activating %s path from %llx:%x to %llx:%x\n",
 446                path->name, tb_route(path->hops[0].in_port->sw),
 447                path->hops[0].in_port->port,
 448                tb_route(path->hops[path->path_length - 1].out_port->sw),
 449                path->hops[path->path_length - 1].out_port->port);
 450 
 451         /* Clear counters. */
 452         for (i = path->path_length - 1; i >= 0; i--) {
 453                 if (path->hops[i].in_counter_index == -1)
 454                         continue;
 455                 res = tb_port_clear_counter(path->hops[i].in_port,
 456                                             path->hops[i].in_counter_index);
 457                 if (res)
 458                         goto err;
 459         }
 460 
 461         /* Add non flow controlled credits. */
 462         for (i = path->path_length - 1; i >= 0; i--) {
 463                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 464                                               path->nfc_credits);
 465                 if (res) {
 466                         __tb_path_deallocate_nfc(path, i);
 467                         goto err;
 468                 }
 469         }
 470 
 471         /* Activate hops. */
 472         for (i = path->path_length - 1; i >= 0; i--) {
 473                 struct tb_regs_hop hop = { 0 };
 474 
 475                 /* If it is left active deactivate it first */
 476                 __tb_path_deactivate_hop(path->hops[i].in_port,
 477                                 path->hops[i].in_hop_index, path->clear_fc);
 478 
 479                 /* dword 0 */
 480                 hop.next_hop = path->hops[i].next_hop_index;
 481                 hop.out_port = path->hops[i].out_port->port;
 482                 hop.initial_credits = path->hops[i].initial_credits;
 483                 hop.unknown1 = 0;
 484                 hop.enable = 1;
 485 
 486                 /* dword 1 */
 487                 out_mask = (i == path->path_length - 1) ?
 488                                 TB_PATH_DESTINATION : TB_PATH_INTERNAL;
 489                 in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
 490                 hop.weight = path->weight;
 491                 hop.unknown2 = 0;
 492                 hop.priority = path->priority;
 493                 hop.drop_packages = path->drop_packages;
 494                 hop.counter = path->hops[i].in_counter_index;
 495                 hop.counter_enable = path->hops[i].in_counter_index != -1;
 496                 hop.ingress_fc = path->ingress_fc_enable & in_mask;
 497                 hop.egress_fc = path->egress_fc_enable & out_mask;
 498                 hop.ingress_shared_buffer = path->ingress_shared_buffer
 499                                             & in_mask;
 500                 hop.egress_shared_buffer = path->egress_shared_buffer
 501                                             & out_mask;
 502                 hop.unknown3 = 0;
 503 
 504                 tb_port_dbg(path->hops[i].in_port, "Writing hop %d\n", i);
 505                 tb_dump_hop(&path->hops[i], &hop);
 506                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
 507                                     2 * path->hops[i].in_hop_index, 2);
 508                 if (res) {
 509                         __tb_path_deactivate_hops(path, i);
 510                         __tb_path_deallocate_nfc(path, 0);
 511                         goto err;
 512                 }
 513         }
 514         path->activated = true;
 515         tb_dbg(path->tb, "path activation complete\n");
 516         return 0;
 517 err:
 518         tb_WARN(path->tb, "path activation failed\n");
 519         return res;
 520 }
 521 
 522 /**
 523  * tb_path_is_invalid() - check whether any ports on the path are invalid
 524  *
 525  * Return: Returns true if the path is invalid, false otherwise.
 526  */
 527 bool tb_path_is_invalid(struct tb_path *path)
 528 {
 529         int i = 0;
 530         for (i = 0; i < path->path_length; i++) {
 531                 if (path->hops[i].in_port->sw->is_unplugged)
 532                         return true;
 533                 if (path->hops[i].out_port->sw->is_unplugged)
 534                         return true;
 535         }
 536         return false;
 537 }