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
tb_dump_hop(const struct tb_path_hop * hop,const struct tb_regs_hop * regs)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
tb_path_find_dst_port(struct tb_port * src,int src_hopid,int dst_hopid)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
tb_path_find_src_hopid(struct tb_port * src,const struct tb_port * dst,int dst_hopid)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 * @alloc_hopid: Allocate HopIDs for the ports
89 *
90 * Follows a path starting from @src and @src_hopid to the last output
91 * port of the path. Allocates HopIDs for the visited ports (if
92 * @alloc_hopid is true). Call tb_path_free() to release the path and
93 * allocated HopIDs when the path is not needed anymore.
94 *
95 * Note function discovers also incomplete paths so caller should check
96 * that the @dst port is the expected one. If it is not, the path can be
97 * cleaned up by calling tb_path_deactivate() before tb_path_free().
98 *
99 * Return: Discovered path on success, %NULL in case of failure
100 */
tb_path_discover(struct tb_port * src,int src_hopid,struct tb_port * dst,int dst_hopid,struct tb_port ** last,const char * name,bool alloc_hopid)101 struct tb_path *tb_path_discover(struct tb_port *src, int src_hopid,
102 struct tb_port *dst, int dst_hopid,
103 struct tb_port **last, const char *name,
104 bool alloc_hopid)
105 {
106 struct tb_port *out_port;
107 struct tb_regs_hop hop;
108 struct tb_path *path;
109 struct tb_switch *sw;
110 struct tb_port *p;
111 size_t num_hops;
112 int ret, i, h;
113
114 if (src_hopid < 0 && dst) {
115 /*
116 * For incomplete paths the intermediate HopID can be
117 * different from the one used by the protocol adapter
118 * so in that case find a path that ends on @dst with
119 * matching @dst_hopid. That should give us the correct
120 * HopID for the @src.
121 */
122 src_hopid = tb_path_find_src_hopid(src, dst, dst_hopid);
123 if (!src_hopid)
124 return NULL;
125 }
126
127 p = src;
128 h = src_hopid;
129 num_hops = 0;
130
131 for (i = 0; p && i < TB_PATH_MAX_HOPS; i++) {
132 sw = p->sw;
133
134 ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
135 if (ret) {
136 tb_port_warn(p, "failed to read path at %d\n", h);
137 return NULL;
138 }
139
140 /* If the hop is not enabled we got an incomplete path */
141 if (!hop.enable)
142 break;
143
144 out_port = &sw->ports[hop.out_port];
145 if (last)
146 *last = out_port;
147
148 h = hop.next_hop;
149 p = out_port->remote;
150 num_hops++;
151 }
152
153 path = kzalloc(sizeof(*path), GFP_KERNEL);
154 if (!path)
155 return NULL;
156
157 path->name = name;
158 path->tb = src->sw->tb;
159 path->path_length = num_hops;
160 path->activated = true;
161 path->alloc_hopid = alloc_hopid;
162
163 path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
164 if (!path->hops) {
165 kfree(path);
166 return NULL;
167 }
168
169 tb_dbg(path->tb, "discovering %s path starting from %llx:%u\n",
170 path->name, tb_route(src->sw), src->port);
171
172 p = src;
173 h = src_hopid;
174
175 for (i = 0; i < num_hops; i++) {
176 int next_hop;
177
178 sw = p->sw;
179
180 ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
181 if (ret) {
182 tb_port_warn(p, "failed to read path at %d\n", h);
183 goto err;
184 }
185
186 if (alloc_hopid && tb_port_alloc_in_hopid(p, h, h) < 0)
187 goto err;
188
189 out_port = &sw->ports[hop.out_port];
190 next_hop = hop.next_hop;
191
192 if (alloc_hopid &&
193 tb_port_alloc_out_hopid(out_port, next_hop, next_hop) < 0) {
194 tb_port_release_in_hopid(p, h);
195 goto err;
196 }
197
198 path->hops[i].in_port = p;
199 path->hops[i].in_hop_index = h;
200 path->hops[i].in_counter_index = -1;
201 path->hops[i].out_port = out_port;
202 path->hops[i].next_hop_index = next_hop;
203
204 tb_dump_hop(&path->hops[i], &hop);
205
206 h = next_hop;
207 p = out_port->remote;
208 }
209
210 tb_dbg(path->tb, "path discovery complete\n");
211 return path;
212
213 err:
214 tb_port_warn(src, "failed to discover path starting at HopID %d\n",
215 src_hopid);
216 tb_path_free(path);
217 return NULL;
218 }
219
220 /**
221 * tb_path_alloc() - allocate a thunderbolt path between two ports
222 * @tb: Domain pointer
223 * @src: Source port of the path
224 * @src_hopid: HopID used for the first ingress port in the path
225 * @dst: Destination port of the path
226 * @dst_hopid: HopID used for the last egress port in the path
227 * @link_nr: Preferred link if there are dual links on the path
228 * @name: Name of the path
229 *
230 * Creates path between two ports starting with given @src_hopid. Reserves
231 * HopIDs for each port (they can be different from @src_hopid depending on
232 * how many HopIDs each port already have reserved). If there are dual
233 * links on the path, prioritizes using @link_nr but takes into account
234 * that the lanes may be bonded.
235 *
236 * Return: Returns a tb_path on success or NULL on failure.
237 */
tb_path_alloc(struct tb * tb,struct tb_port * src,int src_hopid,struct tb_port * dst,int dst_hopid,int link_nr,const char * name)238 struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
239 struct tb_port *dst, int dst_hopid, int link_nr,
240 const char *name)
241 {
242 struct tb_port *in_port, *out_port, *first_port, *last_port;
243 int in_hopid, out_hopid;
244 struct tb_path *path;
245 size_t num_hops;
246 int i, ret;
247
248 path = kzalloc(sizeof(*path), GFP_KERNEL);
249 if (!path)
250 return NULL;
251
252 first_port = last_port = NULL;
253 i = 0;
254 tb_for_each_port_on_path(src, dst, in_port) {
255 if (!first_port)
256 first_port = in_port;
257 last_port = in_port;
258 i++;
259 }
260
261 /* Check that src and dst are reachable */
262 if (first_port != src || last_port != dst) {
263 kfree(path);
264 return NULL;
265 }
266
267 /* Each hop takes two ports */
268 num_hops = i / 2;
269
270 path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
271 if (!path->hops) {
272 kfree(path);
273 return NULL;
274 }
275
276 path->alloc_hopid = true;
277
278 in_hopid = src_hopid;
279 out_port = NULL;
280
281 for (i = 0; i < num_hops; i++) {
282 in_port = tb_next_port_on_path(src, dst, out_port);
283 if (!in_port)
284 goto err;
285
286 /* When lanes are bonded primary link must be used */
287 if (!in_port->bonded && in_port->dual_link_port &&
288 in_port->link_nr != link_nr)
289 in_port = in_port->dual_link_port;
290
291 ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
292 if (ret < 0)
293 goto err;
294 in_hopid = ret;
295
296 out_port = tb_next_port_on_path(src, dst, in_port);
297 if (!out_port)
298 goto err;
299
300 /*
301 * Pick up right port when going from non-bonded to
302 * bonded or from bonded to non-bonded.
303 */
304 if (out_port->dual_link_port) {
305 if (!in_port->bonded && out_port->bonded &&
306 out_port->link_nr) {
307 /*
308 * Use primary link when going from
309 * non-bonded to bonded.
310 */
311 out_port = out_port->dual_link_port;
312 } else if (!out_port->bonded &&
313 out_port->link_nr != link_nr) {
314 /*
315 * If out port is not bonded follow
316 * link_nr.
317 */
318 out_port = out_port->dual_link_port;
319 }
320 }
321
322 if (i == num_hops - 1)
323 ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
324 dst_hopid);
325 else
326 ret = tb_port_alloc_out_hopid(out_port, -1, -1);
327
328 if (ret < 0)
329 goto err;
330 out_hopid = ret;
331
332 path->hops[i].in_hop_index = in_hopid;
333 path->hops[i].in_port = in_port;
334 path->hops[i].in_counter_index = -1;
335 path->hops[i].out_port = out_port;
336 path->hops[i].next_hop_index = out_hopid;
337
338 in_hopid = out_hopid;
339 }
340
341 path->tb = tb;
342 path->path_length = num_hops;
343 path->name = name;
344
345 return path;
346
347 err:
348 tb_path_free(path);
349 return NULL;
350 }
351
352 /**
353 * tb_path_free() - free a path
354 * @path: Path to free
355 *
356 * Frees a path. The path does not need to be deactivated.
357 */
tb_path_free(struct tb_path * path)358 void tb_path_free(struct tb_path *path)
359 {
360 if (path->alloc_hopid) {
361 int i;
362
363 for (i = 0; i < path->path_length; i++) {
364 const struct tb_path_hop *hop = &path->hops[i];
365
366 if (hop->in_port)
367 tb_port_release_in_hopid(hop->in_port,
368 hop->in_hop_index);
369 if (hop->out_port)
370 tb_port_release_out_hopid(hop->out_port,
371 hop->next_hop_index);
372 }
373 }
374
375 kfree(path->hops);
376 kfree(path);
377 }
378
__tb_path_deallocate_nfc(struct tb_path * path,int first_hop)379 static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
380 {
381 int i, res;
382 for (i = first_hop; i < path->path_length; i++) {
383 res = tb_port_add_nfc_credits(path->hops[i].in_port,
384 -path->hops[i].nfc_credits);
385 if (res)
386 tb_port_warn(path->hops[i].in_port,
387 "nfc credits deallocation failed for hop %d\n",
388 i);
389 }
390 }
391
__tb_path_deactivate_hop(struct tb_port * port,int hop_index,bool clear_fc)392 static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index,
393 bool clear_fc)
394 {
395 struct tb_regs_hop hop;
396 ktime_t timeout;
397 int ret;
398
399 /* Disable the path */
400 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
401 if (ret)
402 return ret;
403
404 /* Already disabled */
405 if (!hop.enable)
406 return 0;
407
408 hop.enable = 0;
409
410 ret = tb_port_write(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
411 if (ret)
412 return ret;
413
414 /* Wait until it is drained */
415 timeout = ktime_add_ms(ktime_get(), 500);
416 do {
417 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
418 if (ret)
419 return ret;
420
421 if (!hop.pending) {
422 if (clear_fc) {
423 /*
424 * Clear flow control. Protocol adapters
425 * IFC and ISE bits are vendor defined
426 * in the USB4 spec so we clear them
427 * only for pre-USB4 adapters.
428 */
429 if (!tb_switch_is_usb4(port->sw)) {
430 hop.ingress_fc = 0;
431 hop.ingress_shared_buffer = 0;
432 }
433 hop.egress_fc = 0;
434 hop.egress_shared_buffer = 0;
435
436 return tb_port_write(port, &hop, TB_CFG_HOPS,
437 2 * hop_index, 2);
438 }
439
440 return 0;
441 }
442
443 usleep_range(10, 20);
444 } while (ktime_before(ktime_get(), timeout));
445
446 return -ETIMEDOUT;
447 }
448
449 /**
450 * tb_path_deactivate_hop() - Deactivate one path in path config space
451 * @port: Lane or protocol adapter
452 * @hop_index: HopID of the path to be cleared
453 *
454 * This deactivates or clears a single path config space entry at
455 * @hop_index. Returns %0 in success and negative errno otherwise.
456 */
tb_path_deactivate_hop(struct tb_port * port,int hop_index)457 int tb_path_deactivate_hop(struct tb_port *port, int hop_index)
458 {
459 return __tb_path_deactivate_hop(port, hop_index, true);
460 }
461
__tb_path_deactivate_hops(struct tb_path * path,int first_hop)462 static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
463 {
464 int i, res;
465
466 for (i = first_hop; i < path->path_length; i++) {
467 res = __tb_path_deactivate_hop(path->hops[i].in_port,
468 path->hops[i].in_hop_index,
469 path->clear_fc);
470 if (res && res != -ENODEV)
471 tb_port_warn(path->hops[i].in_port,
472 "hop deactivation failed for hop %d, index %d\n",
473 i, path->hops[i].in_hop_index);
474 }
475 }
476
tb_path_deactivate(struct tb_path * path)477 void tb_path_deactivate(struct tb_path *path)
478 {
479 if (!path->activated) {
480 tb_WARN(path->tb, "trying to deactivate an inactive path\n");
481 return;
482 }
483 tb_dbg(path->tb,
484 "deactivating %s path from %llx:%u to %llx:%u\n",
485 path->name, tb_route(path->hops[0].in_port->sw),
486 path->hops[0].in_port->port,
487 tb_route(path->hops[path->path_length - 1].out_port->sw),
488 path->hops[path->path_length - 1].out_port->port);
489 __tb_path_deactivate_hops(path, 0);
490 __tb_path_deallocate_nfc(path, 0);
491 path->activated = false;
492 }
493
494 /**
495 * tb_path_activate() - activate a path
496 * @path: Path to activate
497 *
498 * Activate a path starting with the last hop and iterating backwards. The
499 * caller must fill path->hops before calling tb_path_activate().
500 *
501 * Return: Returns 0 on success or an error code on failure.
502 */
tb_path_activate(struct tb_path * path)503 int tb_path_activate(struct tb_path *path)
504 {
505 int i, res;
506 enum tb_path_port out_mask, in_mask;
507 if (path->activated) {
508 tb_WARN(path->tb, "trying to activate already activated path\n");
509 return -EINVAL;
510 }
511
512 tb_dbg(path->tb,
513 "activating %s path from %llx:%u to %llx:%u\n",
514 path->name, tb_route(path->hops[0].in_port->sw),
515 path->hops[0].in_port->port,
516 tb_route(path->hops[path->path_length - 1].out_port->sw),
517 path->hops[path->path_length - 1].out_port->port);
518
519 /* Clear counters. */
520 for (i = path->path_length - 1; i >= 0; i--) {
521 if (path->hops[i].in_counter_index == -1)
522 continue;
523 res = tb_port_clear_counter(path->hops[i].in_port,
524 path->hops[i].in_counter_index);
525 if (res)
526 goto err;
527 }
528
529 /* Add non flow controlled credits. */
530 for (i = path->path_length - 1; i >= 0; i--) {
531 res = tb_port_add_nfc_credits(path->hops[i].in_port,
532 path->hops[i].nfc_credits);
533 if (res) {
534 __tb_path_deallocate_nfc(path, i);
535 goto err;
536 }
537 }
538
539 /* Activate hops. */
540 for (i = path->path_length - 1; i >= 0; i--) {
541 struct tb_regs_hop hop = { 0 };
542
543 /* If it is left active deactivate it first */
544 __tb_path_deactivate_hop(path->hops[i].in_port,
545 path->hops[i].in_hop_index, path->clear_fc);
546
547 /* dword 0 */
548 hop.next_hop = path->hops[i].next_hop_index;
549 hop.out_port = path->hops[i].out_port->port;
550 hop.initial_credits = path->hops[i].initial_credits;
551 hop.unknown1 = 0;
552 hop.enable = 1;
553
554 /* dword 1 */
555 out_mask = (i == path->path_length - 1) ?
556 TB_PATH_DESTINATION : TB_PATH_INTERNAL;
557 in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
558 hop.weight = path->weight;
559 hop.unknown2 = 0;
560 hop.priority = path->priority;
561 hop.drop_packages = path->drop_packages;
562 hop.counter = path->hops[i].in_counter_index;
563 hop.counter_enable = path->hops[i].in_counter_index != -1;
564 hop.ingress_fc = path->ingress_fc_enable & in_mask;
565 hop.egress_fc = path->egress_fc_enable & out_mask;
566 hop.ingress_shared_buffer = path->ingress_shared_buffer
567 & in_mask;
568 hop.egress_shared_buffer = path->egress_shared_buffer
569 & out_mask;
570 hop.unknown3 = 0;
571
572 tb_port_dbg(path->hops[i].in_port, "Writing hop %d\n", i);
573 tb_dump_hop(&path->hops[i], &hop);
574 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
575 2 * path->hops[i].in_hop_index, 2);
576 if (res) {
577 __tb_path_deactivate_hops(path, i);
578 __tb_path_deallocate_nfc(path, 0);
579 goto err;
580 }
581 }
582 path->activated = true;
583 tb_dbg(path->tb, "path activation complete\n");
584 return 0;
585 err:
586 tb_WARN(path->tb, "path activation failed\n");
587 return res;
588 }
589
590 /**
591 * tb_path_is_invalid() - check whether any ports on the path are invalid
592 * @path: Path to check
593 *
594 * Return: Returns true if the path is invalid, false otherwise.
595 */
tb_path_is_invalid(struct tb_path * path)596 bool tb_path_is_invalid(struct tb_path *path)
597 {
598 int i = 0;
599 for (i = 0; i < path->path_length; i++) {
600 if (path->hops[i].in_port->sw->is_unplugged)
601 return true;
602 if (path->hops[i].out_port->sw->is_unplugged)
603 return true;
604 }
605 return false;
606 }
607
608 /**
609 * tb_path_port_on_path() - Does the path go through certain port
610 * @path: Path to check
611 * @port: Switch to check
612 *
613 * Goes over all hops on path and checks if @port is any of them.
614 * Direction does not matter.
615 */
tb_path_port_on_path(const struct tb_path * path,const struct tb_port * port)616 bool tb_path_port_on_path(const struct tb_path *path, const struct tb_port *port)
617 {
618 int i;
619
620 for (i = 0; i < path->path_length; i++) {
621 if (path->hops[i].in_port == port ||
622 path->hops[i].out_port == port)
623 return true;
624 }
625
626 return false;
627 }
628