summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/host1x/syncpt.c
blob: a5dbf1ba4645bebb2b7b1ec422cb0adda63470ac (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
/*
 * Tegra host1x Syncpoints
 *
 * Copyright (c) 2010-2015, NVIDIA Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/slab.h>

#include <trace/events/host1x.h>

#include "syncpt.h"
#include "dev.h"
#include "intr.h"
#include "debug.h"

#define SYNCPT_CHECK_PERIOD (2 * HZ)
#define MAX_STUCK_CHECK_COUNT 15

static struct host1x_syncpt_base *
host1x_syncpt_base_request(struct host1x *host)
{
	struct host1x_syncpt_base *bases = host->bases;
	unsigned int i;

	for (i = 0; i < host->info->nb_bases; i++)
		if (!bases[i].requested)
			break;

	if (i >= host->info->nb_bases)
		return NULL;

	bases[i].requested = true;
	return &bases[i];
}

static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
{
	if (base)
		base->requested = false;
}

static struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
						 struct host1x_client *client,
						 unsigned long flags)
{
	struct host1x_syncpt *sp = host->syncpt;
	unsigned int i;
	char *name;

	mutex_lock(&host->syncpt_mutex);

	for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
		;

	if (i >= host->info->nb_pts)
		goto unlock;

	if (flags & HOST1X_SYNCPT_HAS_BASE) {
		sp->base = host1x_syncpt_base_request(host);
		if (!sp->base)
			goto unlock;
	}

	name = kasprintf(GFP_KERNEL, "%02u-%s", sp->id,
			 client ? dev_name(client->dev) : NULL);
	if (!name)
		goto free_base;

	sp->client = client;
	sp->name = name;

	if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
		sp->client_managed = true;
	else
		sp->client_managed = false;

	mutex_unlock(&host->syncpt_mutex);
	return sp;

free_base:
	host1x_syncpt_base_free(sp->base);
	sp->base = NULL;
unlock:
	mutex_unlock(&host->syncpt_mutex);
	return NULL;
}

/**
 * host1x_syncpt_id() - retrieve syncpoint ID
 * @sp: host1x syncpoint
 *
 * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
 * often used as a value to program into registers that control how hardware
 * blocks interact with syncpoints.
 */
u32 host1x_syncpt_id(struct host1x_syncpt *sp)
{
	return sp->id;
}
EXPORT_SYMBOL(host1x_syncpt_id);

/**
 * host1x_syncpt_incr_max() - update the value sent to hardware
 * @sp: host1x syncpoint
 * @incrs: number of increments
 */
u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
{
	return (u32)atomic_add_return(incrs, &sp->max_val);
}
EXPORT_SYMBOL(host1x_syncpt_incr_max);

 /*
 * Write cached syncpoint and waitbase values to hardware.
 */
void host1x_syncpt_restore(struct host1x *host)
{
	struct host1x_syncpt *sp_base = host->syncpt;
	unsigned int i;

	for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
		host1x_hw_syncpt_restore(host, sp_base + i);

	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);

	wmb();
}

/*
 * Update the cached syncpoint and waitbase values by reading them
 * from the registers.
  */
void host1x_syncpt_save(struct host1x *host)
{
	struct host1x_syncpt *sp_base = host->syncpt;
	unsigned int i;

	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
		if (host1x_syncpt_client_managed(sp_base + i))
			host1x_hw_syncpt_load(host, sp_base + i);
		else
			WARN_ON(!host1x_syncpt_idle(sp_base + i));
	}

	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
}

/*
 * Updates the cached syncpoint value by reading a new value from the hardware
 * register
 */
u32 host1x_syncpt_load(struct host1x_syncpt *sp)
{
	u32 val;

	val = host1x_hw_syncpt_load(sp->host, sp);
	trace_host1x_syncpt_load_min(sp->id, val);

	return val;
}

/*
 * Get the current syncpoint base
 */
u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
{
	host1x_hw_syncpt_load_wait_base(sp->host, sp);

	return sp->base_val;
}

/**
 * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
 * @sp: host1x syncpoint
 */
int host1x_syncpt_incr(struct host1x_syncpt *sp)
{
	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
}
EXPORT_SYMBOL(host1x_syncpt_incr);

/*
 * Updated sync point form hardware, and returns true if syncpoint is expired,
 * false if we may need to wait
 */
static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
{
	host1x_hw_syncpt_load(sp->host, sp);

	return host1x_syncpt_is_expired(sp, thresh);
}

/**
 * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
 * @sp: host1x syncpoint
 * @thresh: threshold
 * @timeout: maximum time to wait for the syncpoint to reach the given value
 * @value: return location for the syncpoint value
 */
int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
		       u32 *value)
{
	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
	void *ref;
	struct host1x_waitlist *waiter;
	int err = 0, check_count = 0;
	u32 val;

	if (value)
		*value = 0;

	/* first check cache */
	if (host1x_syncpt_is_expired(sp, thresh)) {
		if (value)
			*value = host1x_syncpt_load(sp);

		return 0;
	}

	/* try to read from register */
	val = host1x_hw_syncpt_load(sp->host, sp);
	if (host1x_syncpt_is_expired(sp, thresh)) {
		if (value)
			*value = val;

		goto done;
	}

	if (!timeout) {
		err = -EAGAIN;
		goto done;
	}

	/* allocate a waiter */
	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
	if (!waiter) {
		err = -ENOMEM;
		goto done;
	}

	/* schedule a wakeup when the syncpoint value is reached */
	err = host1x_intr_add_action(sp->host, sp, thresh,
				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
				     &wq, waiter, &ref);
	if (err)
		goto done;

	err = -EAGAIN;
	/* Caller-specified timeout may be impractically low */
	if (timeout < 0)
		timeout = LONG_MAX;

	/* wait for the syncpoint, or timeout, or signal */
	while (timeout) {
		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
		int remain;

		remain = wait_event_interruptible_timeout(wq,
				syncpt_load_min_is_expired(sp, thresh),
				check);
		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
			if (value)
				*value = host1x_syncpt_load(sp);

			err = 0;

			break;
		}

		if (remain < 0) {
			err = remain;
			break;
		}

		timeout -= check;

		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
			dev_warn(sp->host->dev,
				"%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
				 current->comm, sp->id, sp->name,
				 thresh, timeout);

			host1x_debug_dump_syncpts(sp->host);

			if (check_count == MAX_STUCK_CHECK_COUNT)
				host1x_debug_dump(sp->host);

			check_count++;
		}
	}

	host1x_intr_put_ref(sp->host, sp->id, ref);

done:
	return err;
}
EXPORT_SYMBOL(host1x_syncpt_wait);

/*
 * Returns true if syncpoint is expired, false if we may need to wait
 */
bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
{
	u32 current_val;
	u32 future_val;

	smp_rmb();

	current_val = (u32)atomic_read(&sp->min_val);
	future_val = (u32)atomic_read(&sp->max_val);

	/* Note the use of unsigned arithmetic here (mod 1<<32).
	 *
	 * c = current_val = min_val	= the current value of the syncpoint.
	 * t = thresh			= the value we are checking
	 * f = future_val  = max_val	= the value c will reach when all
	 *				  outstanding increments have completed.
	 *
	 * Note that c always chases f until it reaches f.
	 *
	 * Dtf = (f - t)
	 * Dtc = (c - t)
	 *
	 *  Consider all cases:
	 *
	 *	A) .....c..t..f.....	Dtf < Dtc	need to wait
	 *	B) .....c.....f..t..	Dtf > Dtc	expired
	 *	C) ..t..c.....f.....	Dtf > Dtc	expired	   (Dct very large)
	 *
	 *  Any case where f==c: always expired (for any t).	Dtf == Dcf
	 *  Any case where t==c: always expired (for any f).	Dtf >= Dtc (because Dtc==0)
	 *  Any case where t==f!=c: always wait.		Dtf <  Dtc (because Dtf==0,
	 *							Dtc!=0)
	 *
	 *  Other cases:
	 *
	 *	A) .....t..f..c.....	Dtf < Dtc	need to wait
	 *	A) .....f..c..t.....	Dtf < Dtc	need to wait
	 *	A) .....f..t..c.....	Dtf > Dtc	expired
	 *
	 *   So:
	 *	   Dtf >= Dtc implies EXPIRED	(return true)
	 *	   Dtf <  Dtc implies WAIT	(return false)
	 *
	 * Note: If t is expired then we *cannot* wait on it. We would wait
	 * forever (hang the system).
	 *
	 * Note: do NOT get clever and remove the -thresh from both sides. It
	 * is NOT the same.
	 *
	 * If future valueis zero, we have a client managed sync point. In that
	 * case we do a direct comparison.
	 */
	if (!host1x_syncpt_client_managed(sp))
		return future_val - thresh >= current_val - thresh;
	else
		return (s32)(current_val - thresh) >= 0;
}

int host1x_syncpt_init(struct host1x *host)
{
	struct host1x_syncpt_base *bases;
	struct host1x_syncpt *syncpt;
	unsigned int i;

	syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
			      GFP_KERNEL);
	if (!syncpt)
		return -ENOMEM;

	bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
			     GFP_KERNEL);
	if (!bases)
		return -ENOMEM;

	for (i = 0; i < host->info->nb_pts; i++) {
		syncpt[i].id = i;
		syncpt[i].host = host;

		/*
		 * Unassign syncpt from channels for purposes of Tegra186
		 * syncpoint protection. This prevents any channel from
		 * accessing it until it is reassigned.
		 */
		host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
	}

	for (i = 0; i < host->info->nb_bases; i++)
		bases[i].id = i;

	mutex_init(&host->syncpt_mutex);
	host->syncpt = syncpt;
	host->bases = bases;

	host1x_syncpt_restore(host);
	host1x_hw_syncpt_enable_protection(host);

	/* Allocate sync point to use for clearing waits for expired fences */
	host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
	if (!host->nop_sp)
		return -ENOMEM;

	return 0;
}

/**
 * host1x_syncpt_request() - request a syncpoint
 * @client: client requesting the syncpoint
 * @flags: flags
 *
 * host1x client drivers can use this function to allocate a syncpoint for
 * subsequent use. A syncpoint returned by this function will be reserved for
 * use by the client exclusively. When no longer using a syncpoint, a host1x
 * client driver needs to release it using host1x_syncpt_free().
 */
struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
					    unsigned long flags)
{
	struct host1x *host = dev_get_drvdata(client->parent->parent);

	return host1x_syncpt_alloc(host, client, flags);
}
EXPORT_SYMBOL(host1x_syncpt_request);

/**
 * host1x_syncpt_free() - free a requested syncpoint
 * @sp: host1x syncpoint
 *
 * Release a syncpoint previously allocated using host1x_syncpt_request(). A
 * host1x client driver should call this when the syncpoint is no longer in
 * use. Note that client drivers must ensure that the syncpoint doesn't remain
 * under the control of hardware after calling this function, otherwise two
 * clients may end up trying to access the same syncpoint concurrently.
 */
void host1x_syncpt_free(struct host1x_syncpt *sp)
{
	if (!sp)
		return;

	mutex_lock(&sp->host->syncpt_mutex);

	host1x_syncpt_base_free(sp->base);
	kfree(sp->name);
	sp->base = NULL;
	sp->client = NULL;
	sp->name = NULL;
	sp->client_managed = false;

	mutex_unlock(&sp->host->syncpt_mutex);
}
EXPORT_SYMBOL(host1x_syncpt_free);

void host1x_syncpt_deinit(struct host1x *host)
{
	struct host1x_syncpt *sp = host->syncpt;
	unsigned int i;

	for (i = 0; i < host->info->nb_pts; i++, sp++)
		kfree(sp->name);
}

/**
 * host1x_syncpt_read_max() - read maximum syncpoint value
 * @sp: host1x syncpoint
 *
 * The maximum syncpoint value indicates how many operations there are in
 * queue, either in channel or in a software thread.
 */
u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
{
	smp_rmb();

	return (u32)atomic_read(&sp->max_val);
}
EXPORT_SYMBOL(host1x_syncpt_read_max);

/**
 * host1x_syncpt_read_min() - read minimum syncpoint value
 * @sp: host1x syncpoint
 *
 * The minimum syncpoint value is a shadow of the current sync point value in
 * hardware.
 */
u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
{
	smp_rmb();

	return (u32)atomic_read(&sp->min_val);
}
EXPORT_SYMBOL(host1x_syncpt_read_min);

/**
 * host1x_syncpt_read() - read the current syncpoint value
 * @sp: host1x syncpoint
 */
u32 host1x_syncpt_read(struct host1x_syncpt *sp)
{
	return host1x_syncpt_load(sp);
}
EXPORT_SYMBOL(host1x_syncpt_read);

unsigned int host1x_syncpt_nb_pts(struct host1x *host)
{
	return host->info->nb_pts;
}

unsigned int host1x_syncpt_nb_bases(struct host1x *host)
{
	return host->info->nb_bases;
}

unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
{
	return host->info->nb_mlocks;
}

/**
 * host1x_syncpt_get() - obtain a syncpoint by ID
 * @host: host1x controller
 * @id: syncpoint ID
 */
struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
{
	if (id >= host->info->nb_pts)
		return NULL;

	return host->syncpt + id;
}
EXPORT_SYMBOL(host1x_syncpt_get);

/**
 * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
 * @sp: host1x syncpoint
 */
struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
{
	return sp ? sp->base : NULL;
}
EXPORT_SYMBOL(host1x_syncpt_get_base);

/**
 * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
 * @base: host1x syncpoint wait base
 */
u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
{
	return base->id;
}
EXPORT_SYMBOL(host1x_syncpt_base_id);