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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\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}