summaryrefslogtreecommitdiffstats
path: root/drivers/thunderbolt/path.c
blob: ca7d738d66dea0961a58a1da7e7054f71293425d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt driver - path/tunnel functionality
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 * Copyright (C) 2019, Intel Corporation
 */

#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/ktime.h>

#include "tb.h"

static void tb_dump_hop(const struct tb_path_hop *hop, const struct tb_regs_hop *regs)
{
	const struct tb_port *port = hop->in_port;

	tb_port_dbg(port, " In HopID: %d => Out port: %d Out HopID: %d\n",
		    hop->in_hop_index, regs->out_port, regs->next_hop);
	tb_port_dbg(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
		    regs->weight, regs->priority,
		    regs->initial_credits, regs->drop_packages);
	tb_port_dbg(port, "   Counter enabled: %d Counter index: %d\n",
		    regs->counter_enable, regs->counter);
	tb_port_dbg(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
		    regs->ingress_fc, regs->egress_fc,
		    regs->ingress_shared_buffer, regs->egress_shared_buffer);
	tb_port_dbg(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
		    regs->unknown1, regs->unknown2, regs->unknown3);
}

static struct tb_port *tb_path_find_dst_port(struct tb_port *src, int src_hopid,
					     int dst_hopid)
{
	struct tb_port *port, *out_port = NULL;
	struct tb_regs_hop hop;
	struct tb_switch *sw;
	int i, ret, hopid;

	hopid = src_hopid;
	port = src;

	for (i = 0; port && i < TB_PATH_MAX_HOPS; i++) {
		sw = port->sw;

		ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hopid, 2);
		if (ret) {
			tb_port_warn(port, "failed to read path at %d\n", hopid);
			return NULL;
		}

		if (!hop.enable)
			return NULL;

		out_port = &sw->ports[hop.out_port];
		hopid = hop.next_hop;
		port = out_port->remote;
	}

	return out_port && hopid == dst_hopid ? out_port : NULL;
}

static int tb_path_find_src_hopid(struct tb_port *src,
	const struct tb_port *dst, int dst_hopid)
{
	struct tb_port *out;
	int i;

	for (i = TB_PATH_MIN_HOPID; i <= src->config.max_in_hop_id; i++) {
		out = tb_path_find_dst_port(src, i, dst_hopid);
		if (out == dst)
			return i;
	}

	return 0;
}

/**
 * tb_path_discover() - Discover a path
 * @src: First input port of a path
 * @src_hopid: Starting HopID of a path (%-1 if don't care)
 * @dst: Expected destination port of the path (%NULL if don't care)
 * @dst_hopid: HopID to the @dst (%-1 if don't care)
 * @last: Last port is filled here if not %NULL
 * @name: Name of the path
 *
 * Follows a path starting from @src and @src_hopid to the last output
 * port of the path. Allocates HopIDs for the visited ports. Call
 * tb_path_free() to release the path and allocated HopIDs when the path
 * is not needed anymore.
 *
 * Note function discovers also incomplete paths so caller should check
 * that the @dst port is the expected one. If it is not, the path can be
 * cleaned up by calling tb_path_deactivate() before tb_path_free().
 *
 * Return: Discovered path on success, %NULL in case of failure
 */
struct tb_path *tb_path_discover(struct tb_port *src, int src_hopid,
				 struct tb_port *dst, int dst_hopid,
				 struct tb_port **last, const char *name)
{
	struct tb_port *out_port;
	struct tb_regs_hop hop;
	struct tb_path *path;
	struct tb_switch *sw;
	struct tb_port *p;
	size_t num_hops;
	int ret, i, h;

	if (src_hopid < 0 && dst) {
		/*
		 * For incomplete paths the intermediate HopID can be
		 * different from the one used by the protocol adapter
		 * so in that case find a path that ends on @dst with
		 * matching @dst_hopid. That should give us the correct
		 * HopID for the @src.
		 */
		src_hopid = tb_path_find_src_hopid(src, dst, dst_hopid);
		if (!src_hopid)
			return NULL;
	}

	p = src;
	h = src_hopid;
	num_hops = 0;

	for (i = 0; p && i < TB_PATH_MAX_HOPS; i++) {
		sw = p->sw;

		ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
		if (ret) {
			tb_port_warn(p, "failed to read path at %d\n", h);
			return NULL;
		}

		/* If the hop is not enabled we got an incomplete path */
		if (!hop.enable)
			break;

		out_port = &sw->ports[hop.out_port];
		if (last)
			*last = out_port;

		h = hop.next_hop;
		p = out_port->remote;
		num_hops++;
	}

	path = kzalloc(sizeof(*path), GFP_KERNEL);
	if (!path)
		return NULL;

	path->name = name;
	path->tb = src->sw->tb;
	path->path_length = num_hops;
	path->activated = true;

	path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
	if (!path->hops) {
		kfree(path);
		return NULL;
	}

	p = src;
	h = src_hopid;

	for (i = 0; i < num_hops; i++) {
		int next_hop;

		sw = p->sw;

		ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
		if (ret) {
			tb_port_warn(p, "failed to read path at %d\n", h);
			goto err;
		}

		if (tb_port_alloc_in_hopid(p, h, h) < 0)
			goto err;

		out_port = &sw->ports[hop.out_port];
		next_hop = hop.next_hop;

		if (tb_port_alloc_out_hopid(out_port, next_hop, next_hop) < 0) {
			tb_port_release_in_hopid(p, h);
			goto err;
		}

		path->hops[i].in_port = p;
		path->hops[i].in_hop_index = h;
		path->hops[i].in_counter_index = -1;
		path->hops[i].out_port = out_port;
		path->hops[i].next_hop_index = next_hop;

		h = next_hop;
		p = out_port->remote;
	}

	return path;

err:
	tb_port_warn(src, "failed to discover path starting at HopID %d\n",
		     src_hopid);
	tb_path_free(path);
	return NULL;
}

/**
 * tb_path_alloc() - allocate a thunderbolt path between two ports
 * @tb: Domain pointer
 * @src: Source port of the path
 * @src_hopid: HopID used for the first ingress port in the path
 * @dst: Destination port of the path
 * @dst_hopid: HopID used for the last egress port in the path
 * @link_nr: Preferred link if there are dual links on the path
 * @name: Name of the path
 *
 * Creates path between two ports starting with given @src_hopid. Reserves
 * HopIDs for each port (they can be different from @src_hopid depending on
 * how many HopIDs each port already have reserved). If there are dual
 * links on the path, prioritizes using @link_nr but takes into account
 * that the lanes may be bonded.
 *
 * Return: Returns a tb_path on success or NULL on failure.
 */
struct tb_path *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)
{
	struct tb_port *in_port, *out_port, *first_port, *last_port;
	int in_hopid, out_hopid;
	struct tb_path *path;
	size_t num_hops;
	int i, ret;

	path = kzalloc(sizeof(*path), GFP_KERNEL);
	if (!path)
		return NULL;

	first_port = last_port = NULL;
	i = 0;
	tb_for_each_port_on_path(src, dst, in_port) {
		if (!first_port)
			first_port = in_port;
		last_port = in_port;
		i++;
	}

	/* Check that src and dst are reachable */
	if (first_port != src || last_port != dst) {
		kfree(path);
		return NULL;
	}

	/* Each hop takes two ports */
	num_hops = i / 2;

	path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
	if (!path->hops) {
		kfree(path);
		return NULL;
	}

	in_hopid = src_hopid;
	out_port = NULL;

	for (i = 0; i < num_hops; i++) {
		in_port = tb_next_port_on_path(src, dst, out_port);
		if (!in_port)
			goto err;

		/* When lanes are bonded primary link must be used */
		if (!in_port->bonded && in_port->dual_link_port &&
		    in_port->link_nr != link_nr)
			in_port = in_port->dual_link_port;

		ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
		if (ret < 0)
			goto err;
		in_hopid = ret;

		out_port = tb_next_port_on_path(src, dst, in_port);
		if (!out_port)
			goto err;

		/*
		 * Pick up right port when going from non-bonded to
		 * bonded or from bonded to non-bonded.
		 */
		if (out_port->dual_link_port) {
			if (!in_port->bonded && out_port->bonded &&
			    out_port->link_nr) {
				/*
				 * Use primary link when going from
				 * non-bonded to bonded.
				 */
				out_port = out_port->dual_link_port;
			} else if (!out_port->bonded &&
				   out_port->link_nr != link_nr) {
				/*
				 * If out port is not bonded follow
				 * link_nr.
				 */
				out_port = out_port->dual_link_port;
			}
		}

		if (i == num_hops - 1)
			ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
						      dst_hopid);
		else
			ret = tb_port_alloc_out_hopid(out_port, -1, -1);

		if (ret < 0)
			goto err;
		out_hopid = ret;

		path->hops[i].in_hop_index = in_hopid;
		path->hops[i].in_port = in_port;
		path->hops[i].in_counter_index = -1;
		path->hops[i].out_port = out_port;
		path->hops[i].next_hop_index = out_hopid;

		in_hopid = out_hopid;
	}

	path->tb = tb;
	path->path_length = num_hops;
	path->name = name;

	return path;

err:
	tb_path_free(path);
	return NULL;
}

/**
 * tb_path_free() - free a path
 * @path: Path to free
 *
 * Frees a path. The path does not need to be deactivated.
 */
void tb_path_free(struct tb_path *path)
{
	int i;

	for (i = 0; i < path->path_length; i++) {
		const struct tb_path_hop *hop = &path->hops[i];

		if (hop->in_port)
			tb_port_release_in_hopid(hop->in_port,
						 hop->in_hop_index);
		if (hop->out_port)
			tb_port_release_out_hopid(hop->out_port,
						  hop->next_hop_index);
	}

	kfree(path->hops);
	kfree(path);
}

static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
{
	int i, res;
	for (i = first_hop; i < path->path_length; i++) {
		res = tb_port_add_nfc_credits(path->hops[i].in_port,
					      -path->nfc_credits);
		if (res)
			tb_port_warn(path->hops[i].in_port,
				     "nfc credits deallocation failed for hop %d\n",
				     i);
	}
}

static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index,
				    bool clear_fc)
{
	struct tb_regs_hop hop;
	ktime_t timeout;
	int ret;

	/* Disable the path */
	ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
	if (ret)
		return ret;

	/* Already disabled */
	if (!hop.enable)
		return 0;

	hop.enable = 0;

	ret = tb_port_write(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
	if (ret)
		return ret;

	/* Wait until it is drained */
	timeout = ktime_add_ms(ktime_get(), 500);
	do {
		ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
		if (ret)
			return ret;

		if (!hop.pending) {
			if (clear_fc) {
				/*
				 * Clear flow control. Protocol adapters
				 * IFC and ISE bits are vendor defined
				 * in the USB4 spec so we clear them
				 * only for pre-USB4 adapters.
				 */
				if (!tb_switch_is_usb4(port->sw)) {
					hop.ingress_fc = 0;
					hop.ingress_shared_buffer = 0;
				}
				hop.egress_fc = 0;
				hop.egress_shared_buffer = 0;

				return tb_port_write(port, &hop, TB_CFG_HOPS,
						     2 * hop_index, 2);
			}

			return 0;
		}

		usleep_range(10, 20);
	} while (ktime_before(ktime_get(), timeout));

	return -ETIMEDOUT;
}

static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
{
	int i, res;

	for (i = first_hop; i < path->path_length; i++) {
		res = __tb_path_deactivate_hop(path->hops[i].in_port,
					       path->hops[i].in_hop_index,
					       path->clear_fc);
		if (res && res != -ENODEV)
			tb_port_warn(path->hops[i].in_port,
				     "hop deactivation failed for hop %d, index %d\n",
				     i, path->hops[i].in_hop_index);
	}
}

void tb_path_deactivate(struct tb_path *path)
{
	if (!path->activated) {
		tb_WARN(path->tb, "trying to deactivate an inactive path\n");
		return;
	}
	tb_dbg(path->tb,
	       "deactivating %s path from %llx:%u to %llx:%u\n",
	       path->name, tb_route(path->hops[0].in_port->sw),
	       path->hops[0].in_port->port,
	       tb_route(path->hops[path->path_length - 1].out_port->sw),
	       path->hops[path->path_length - 1].out_port->port);
	__tb_path_deactivate_hops(path, 0);
	__tb_path_deallocate_nfc(path, 0);
	path->activated = false;
}

/**
 * tb_path_activate() - activate a path
 *
 * Activate a path starting with the last hop and iterating backwards. The
 * caller must fill path->hops before calling tb_path_activate().
 *
 * Return: Returns 0 on success or an error code on failure.
 */
int tb_path_activate(struct tb_path *path)
{
	int i, res;
	enum tb_path_port out_mask, in_mask;
	if (path->activated) {
		tb_WARN(path->tb, "trying to activate already activated path\n");
		return -EINVAL;
	}

	tb_dbg(path->tb,
	       "activating %s path from %llx:%u to %llx:%u\n",
	       path->name, tb_route(path->hops[0].in_port->sw),
	       path->hops[0].in_port->port,
	       tb_route(path->hops[path->path_length - 1].out_port->sw),
	       path->hops[path->path_length - 1].out_port->port);

	/* Clear counters. */
	for (i = path->path_length - 1; i >= 0; i--) {
		if (path->hops[i].in_counter_index == -1)
			continue;
		res = tb_port_clear_counter(path->hops[i].in_port,
					    path->hops[i].in_counter_index);
		if (res)
			goto err;
	}

	/* Add non flow controlled credits. */
	for (i = path->path_length - 1; i >= 0; i--) {
		res = tb_port_add_nfc_credits(path->hops[i].in_port,
					      path->nfc_credits);
		if (res) {
			__tb_path_deallocate_nfc(path, i);
			goto err;
		}
	}

	/* Activate hops. */
	for (i = path->path_length - 1; i >= 0; i--) {
		struct tb_regs_hop hop = { 0 };

		/* If it is left active deactivate it first */
		__tb_path_deactivate_hop(path->hops[i].in_port,
				path->hops[i].in_hop_index, path->clear_fc);

		/* dword 0 */
		hop.next_hop = path->hops[i].next_hop_index;
		hop.out_port = path->hops[i].out_port->port;
		hop.initial_credits = path->hops[i].initial_credits;
		hop.unknown1 = 0;
		hop.enable = 1;

		/* dword 1 */
		out_mask = (i == path->path_length - 1) ?
				TB_PATH_DESTINATION : TB_PATH_INTERNAL;
		in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
		hop.weight = path->weight;
		hop.unknown2 = 0;
		hop.priority = path->priority;
		hop.drop_packages = path->drop_packages;
		hop.counter = path->hops[i].in_counter_index;
		hop.counter_enable = path->hops[i].in_counter_index != -1;
		hop.ingress_fc = path->ingress_fc_enable & in_mask;
		hop.egress_fc = path->egress_fc_enable & out_mask;
		hop.ingress_shared_buffer = path->ingress_shared_buffer
					    & in_mask;
		hop.egress_shared_buffer = path->egress_shared_buffer
					    & out_mask;
		hop.unknown3 = 0;

		tb_port_dbg(path->hops[i].in_port, "Writing hop %d\n", i);
		tb_dump_hop(&path->hops[i], &hop);
		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
				    2 * path->hops[i].in_hop_index, 2);
		if (res) {
			__tb_path_deactivate_hops(path, i);
			__tb_path_deallocate_nfc(path, 0);
			goto err;
		}
	}
	path->activated = true;
	tb_dbg(path->tb, "path activation complete\n");
	return 0;
err:
	tb_WARN(path->tb, "path activation failed\n");
	return res;
}

/**
 * tb_path_is_invalid() - check whether any ports on the path are invalid
 *
 * Return: Returns true if the path is invalid, false otherwise.
 */
bool tb_path_is_invalid(struct tb_path *path)
{
	int i = 0;
	for (i = 0; i < path->path_length; i++) {
		if (path->hops[i].in_port->sw->is_unplugged)
			return true;
		if (path->hops[i].out_port->sw->is_unplugged)
			return true;
	}
	return false;
}

/**
 * tb_path_port_on_path() - Does the path go through certain port
 * @path: Path to check
 * @port: Switch to check
 *
 * Goes over all hops on path and checks if @port is any of them.
 * Direction does not matter.
 */
bool tb_path_port_on_path(const struct tb_path *path, const struct tb_port *port)
{
	int i;

	for (i = 0; i < path->path_length; i++) {
		if (path->hops[i].in_port == port ||
		    path->hops[i].out_port == port)
			return true;
	}

	return false;
}