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 } 538