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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
16static 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 PM: %d\n",
23 regs->weight, regs->priority, regs->initial_credits,
24 regs->drop_packages, regs->pmps);
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
34static 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
65static 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 */
101struct 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
213err:
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 */
238struct 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
347err:
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 */
358void 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
379static 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
392static 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
449static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
450{
451 int i, res;
452
453 for (i = first_hop; i < path->path_length; i++) {
454 res = __tb_path_deactivate_hop(path->hops[i].in_port,
455 path->hops[i].in_hop_index,
456 path->clear_fc);
457 if (res && res != -ENODEV)
458 tb_port_warn(path->hops[i].in_port,
459 "hop deactivation failed for hop %d, index %d\n",
460 i, path->hops[i].in_hop_index);
461 }
462}
463
464void tb_path_deactivate(struct tb_path *path)
465{
466 if (!path->activated) {
467 tb_WARN(path->tb, "trying to deactivate an inactive path\n");
468 return;
469 }
470 tb_dbg(path->tb,
471 "deactivating %s path from %llx:%u to %llx:%u\n",
472 path->name, tb_route(path->hops[0].in_port->sw),
473 path->hops[0].in_port->port,
474 tb_route(path->hops[path->path_length - 1].out_port->sw),
475 path->hops[path->path_length - 1].out_port->port);
476 __tb_path_deactivate_hops(path, 0);
477 __tb_path_deallocate_nfc(path, 0);
478 path->activated = false;
479}
480
481/**
482 * tb_path_activate() - activate a path
483 * @path: Path to activate
484 *
485 * Activate a path starting with the last hop and iterating backwards. The
486 * caller must fill path->hops before calling tb_path_activate().
487 *
488 * Return: Returns 0 on success or an error code on failure.
489 */
490int tb_path_activate(struct tb_path *path)
491{
492 int i, res;
493 enum tb_path_port out_mask, in_mask;
494 if (path->activated) {
495 tb_WARN(path->tb, "trying to activate already activated path\n");
496 return -EINVAL;
497 }
498
499 tb_dbg(path->tb,
500 "activating %s path from %llx:%u to %llx:%u\n",
501 path->name, tb_route(path->hops[0].in_port->sw),
502 path->hops[0].in_port->port,
503 tb_route(path->hops[path->path_length - 1].out_port->sw),
504 path->hops[path->path_length - 1].out_port->port);
505
506 /* Clear counters. */
507 for (i = path->path_length - 1; i >= 0; i--) {
508 if (path->hops[i].in_counter_index == -1)
509 continue;
510 res = tb_port_clear_counter(path->hops[i].in_port,
511 path->hops[i].in_counter_index);
512 if (res)
513 goto err;
514 }
515
516 /* Add non flow controlled credits. */
517 for (i = path->path_length - 1; i >= 0; i--) {
518 res = tb_port_add_nfc_credits(path->hops[i].in_port,
519 path->hops[i].nfc_credits);
520 if (res) {
521 __tb_path_deallocate_nfc(path, i);
522 goto err;
523 }
524 }
525
526 /* Activate hops. */
527 for (i = path->path_length - 1; i >= 0; i--) {
528 struct tb_regs_hop hop = { 0 };
529
530 /* If it is left active deactivate it first */
531 __tb_path_deactivate_hop(path->hops[i].in_port,
532 path->hops[i].in_hop_index, path->clear_fc);
533
534 /* dword 0 */
535 hop.next_hop = path->hops[i].next_hop_index;
536 hop.out_port = path->hops[i].out_port->port;
537 hop.initial_credits = path->hops[i].initial_credits;
538 hop.pmps = path->hops[i].pm_support;
539 hop.unknown1 = 0;
540 hop.enable = 1;
541
542 /* dword 1 */
543 out_mask = (i == path->path_length - 1) ?
544 TB_PATH_DESTINATION : TB_PATH_INTERNAL;
545 in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
546 hop.weight = path->weight;
547 hop.unknown2 = 0;
548 hop.priority = path->priority;
549 hop.drop_packages = path->drop_packages;
550 hop.counter = path->hops[i].in_counter_index;
551 hop.counter_enable = path->hops[i].in_counter_index != -1;
552 hop.ingress_fc = path->ingress_fc_enable & in_mask;
553 hop.egress_fc = path->egress_fc_enable & out_mask;
554 hop.ingress_shared_buffer = path->ingress_shared_buffer
555 & in_mask;
556 hop.egress_shared_buffer = path->egress_shared_buffer
557 & out_mask;
558 hop.unknown3 = 0;
559
560 tb_port_dbg(path->hops[i].in_port, "Writing hop %d\n", i);
561 tb_dump_hop(&path->hops[i], &hop);
562 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
563 2 * path->hops[i].in_hop_index, 2);
564 if (res) {
565 __tb_path_deactivate_hops(path, i);
566 __tb_path_deallocate_nfc(path, 0);
567 goto err;
568 }
569 }
570 path->activated = true;
571 tb_dbg(path->tb, "path activation complete\n");
572 return 0;
573err:
574 tb_WARN(path->tb, "path activation failed\n");
575 return res;
576}
577
578/**
579 * tb_path_is_invalid() - check whether any ports on the path are invalid
580 * @path: Path to check
581 *
582 * Return: Returns true if the path is invalid, false otherwise.
583 */
584bool tb_path_is_invalid(struct tb_path *path)
585{
586 int i = 0;
587 for (i = 0; i < path->path_length; i++) {
588 if (path->hops[i].in_port->sw->is_unplugged)
589 return true;
590 if (path->hops[i].out_port->sw->is_unplugged)
591 return true;
592 }
593 return false;
594}
595
596/**
597 * tb_path_port_on_path() - Does the path go through certain port
598 * @path: Path to check
599 * @port: Switch to check
600 *
601 * Goes over all hops on path and checks if @port is any of them.
602 * Direction does not matter.
603 */
604bool tb_path_port_on_path(const struct tb_path *path, const struct tb_port *port)
605{
606 int i;
607
608 for (i = 0; i < path->path_length; i++) {
609 if (path->hops[i].in_port == port ||
610 path->hops[i].out_port == port)
611 return true;
612 }
613
614 return false;
615}
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
16static 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
34static 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
65static 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 */
100struct 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
203err:
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 */
227struct 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
302err:
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 */
313void 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
332static 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
345static 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
395static 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
410void 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 */
435int 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;
517err:
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 */
527bool 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}