summaryrefslogtreecommitdiff
path: root/drivers/media/v4l2-core/v4l2-async.c
blob: 2b08d03b251d6053aa9db3ccae0c5b8c2cbbdf90 (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
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
/*
 * V4L2 asynchronous subdevice registration API
 *
 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <media/v4l2-async.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-subdev.h>

static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
					  struct v4l2_subdev *subdev,
					  struct v4l2_async_subdev *asd)
{
	if (!n->ops || !n->ops->bound)
		return 0;

	return n->ops->bound(n, subdev, asd);
}

static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
					    struct v4l2_subdev *subdev,
					    struct v4l2_async_subdev *asd)
{
	if (!n->ops || !n->ops->unbind)
		return;

	n->ops->unbind(n, subdev, asd);
}

static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
{
	if (!n->ops || !n->ops->complete)
		return 0;

	return n->ops->complete(n);
}

static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
#if IS_ENABLED(CONFIG_I2C)
	struct i2c_client *client = i2c_verify_client(sd->dev);
	return client &&
		asd->match.i2c.adapter_id == client->adapter->nr &&
		asd->match.i2c.address == client->addr;
#else
	return false;
#endif
}

static bool match_devname(struct v4l2_subdev *sd,
			  struct v4l2_async_subdev *asd)
{
	return !strcmp(asd->match.device_name, dev_name(sd->dev));
}

static bool match_fwnode(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
	return sd->fwnode == asd->match.fwnode;
}

static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
	if (!asd->match.custom.match)
		/* Match always */
		return true;

	return asd->match.custom.match(sd->dev, asd);
}

static LIST_HEAD(subdev_list);
static LIST_HEAD(notifier_list);
static DEFINE_MUTEX(list_lock);

static struct v4l2_async_subdev *v4l2_async_find_match(
	struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd)
{
	bool (*match)(struct v4l2_subdev *, struct v4l2_async_subdev *);
	struct v4l2_async_subdev *asd;

	list_for_each_entry(asd, &notifier->waiting, list) {
		/* bus_type has been verified valid before */
		switch (asd->match_type) {
		case V4L2_ASYNC_MATCH_CUSTOM:
			match = match_custom;
			break;
		case V4L2_ASYNC_MATCH_DEVNAME:
			match = match_devname;
			break;
		case V4L2_ASYNC_MATCH_I2C:
			match = match_i2c;
			break;
		case V4L2_ASYNC_MATCH_FWNODE:
			match = match_fwnode;
			break;
		default:
			/* Cannot happen, unless someone breaks us */
			WARN_ON(true);
			return NULL;
		}

		/* match cannot be NULL here */
		if (match(sd, asd))
			return asd;
	}

	return NULL;
}

/* Find the sub-device notifier registered by a sub-device driver. */
static struct v4l2_async_notifier *v4l2_async_find_subdev_notifier(
	struct v4l2_subdev *sd)
{
	struct v4l2_async_notifier *n;

	list_for_each_entry(n, &notifier_list, list)
		if (n->sd == sd)
			return n;

	return NULL;
}

/* Get v4l2_device related to the notifier if one can be found. */
static struct v4l2_device *v4l2_async_notifier_find_v4l2_dev(
	struct v4l2_async_notifier *notifier)
{
	while (notifier->parent)
		notifier = notifier->parent;

	return notifier->v4l2_dev;
}

/*
 * Return true if all child sub-device notifiers are complete, false otherwise.
 */
static bool v4l2_async_notifier_can_complete(
	struct v4l2_async_notifier *notifier)
{
	struct v4l2_subdev *sd;

	if (!list_empty(&notifier->waiting))
		return false;

	list_for_each_entry(sd, &notifier->done, async_list) {
		struct v4l2_async_notifier *subdev_notifier =
			v4l2_async_find_subdev_notifier(sd);

		if (subdev_notifier &&
		    !v4l2_async_notifier_can_complete(subdev_notifier))
			return false;
	}

	return true;
}

/*
 * Complete the master notifier if possible. This is done when all async
 * sub-devices have been bound; v4l2_device is also available then.
 */
static int v4l2_async_notifier_try_complete(
	struct v4l2_async_notifier *notifier)
{
	/* Quick check whether there are still more sub-devices here. */
	if (!list_empty(&notifier->waiting))
		return 0;

	/* Check the entire notifier tree; find the root notifier first. */
	while (notifier->parent)
		notifier = notifier->parent;

	/* This is root if it has v4l2_dev. */
	if (!notifier->v4l2_dev)
		return 0;

	/* Is everything ready? */
	if (!v4l2_async_notifier_can_complete(notifier))
		return 0;

	return v4l2_async_notifier_call_complete(notifier);
}

static int v4l2_async_notifier_try_all_subdevs(
	struct v4l2_async_notifier *notifier);

static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
				   struct v4l2_device *v4l2_dev,
				   struct v4l2_subdev *sd,
				   struct v4l2_async_subdev *asd)
{
	struct v4l2_async_notifier *subdev_notifier;
	int ret;

	ret = v4l2_device_register_subdev(v4l2_dev, sd);
	if (ret < 0)
		return ret;

	ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
	if (ret < 0) {
		v4l2_device_unregister_subdev(sd);
		return ret;
	}

	/* Remove from the waiting list */
	list_del(&asd->list);
	sd->asd = asd;
	sd->notifier = notifier;

	/* Move from the global subdevice list to notifier's done */
	list_move(&sd->async_list, &notifier->done);

	/*
	 * See if the sub-device has a notifier. If not, return here.
	 */
	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
	if (!subdev_notifier || subdev_notifier->parent)
		return 0;

	/*
	 * Proceed with checking for the sub-device notifier's async
	 * sub-devices, and return the result. The error will be handled by the
	 * caller.
	 */
	subdev_notifier->parent = notifier;

	return v4l2_async_notifier_try_all_subdevs(subdev_notifier);
}

/* Test all async sub-devices in a notifier for a match. */
static int v4l2_async_notifier_try_all_subdevs(
	struct v4l2_async_notifier *notifier)
{
	struct v4l2_device *v4l2_dev =
		v4l2_async_notifier_find_v4l2_dev(notifier);
	struct v4l2_subdev *sd;

	if (!v4l2_dev)
		return 0;

again:
	list_for_each_entry(sd, &subdev_list, async_list) {
		struct v4l2_async_subdev *asd;
		int ret;

		asd = v4l2_async_find_match(notifier, sd);
		if (!asd)
			continue;

		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
		if (ret < 0)
			return ret;

		/*
		 * v4l2_async_match_notify() may lead to registering a
		 * new notifier and thus changing the async subdevs
		 * list. In order to proceed safely from here, restart
		 * parsing the list from the beginning.
		 */
		goto again;
	}

	return 0;
}

static void v4l2_async_cleanup(struct v4l2_subdev *sd)
{
	v4l2_device_unregister_subdev(sd);
	/* Subdevice driver will reprobe and put the subdev back onto the list */
	list_del_init(&sd->async_list);
	sd->asd = NULL;
}

/* Unbind all sub-devices in the notifier tree. */
static void v4l2_async_notifier_unbind_all_subdevs(
	struct v4l2_async_notifier *notifier)
{
	struct v4l2_subdev *sd, *tmp;

	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
		struct v4l2_async_notifier *subdev_notifier =
			v4l2_async_find_subdev_notifier(sd);

		if (subdev_notifier)
			v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);

		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
		v4l2_async_cleanup(sd);

		list_move(&sd->async_list, &subdev_list);
	}

	notifier->parent = NULL;
}

/* See if an fwnode can be found in a notifier's lists. */
static bool __v4l2_async_notifier_fwnode_has_async_subdev(
	struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode)
{
	struct v4l2_async_subdev *asd;
	struct v4l2_subdev *sd;

	list_for_each_entry(asd, &notifier->waiting, list) {
		if (asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
			continue;

		if (asd->match.fwnode == fwnode)
			return true;
	}

	list_for_each_entry(sd, &notifier->done, async_list) {
		if (WARN_ON(!sd->asd))
			continue;

		if (sd->asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
			continue;

		if (sd->asd->match.fwnode == fwnode)
			return true;
	}

	return false;
}

/*
 * Find out whether an async sub-device was set up for an fwnode already or
 * whether it exists in a given notifier before @this_index.
 */
static bool v4l2_async_notifier_fwnode_has_async_subdev(
	struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode,
	unsigned int this_index)
{
	unsigned int j;

	lockdep_assert_held(&list_lock);

	/* Check that an fwnode is not being added more than once. */
	for (j = 0; j < this_index; j++) {
		struct v4l2_async_subdev *asd = notifier->subdevs[this_index];
		struct v4l2_async_subdev *other_asd = notifier->subdevs[j];

		if (other_asd->match_type == V4L2_ASYNC_MATCH_FWNODE &&
		    asd->match.fwnode ==
		    other_asd->match.fwnode)
			return true;
	}

	/* Check than an fwnode did not exist in other notifiers. */
	list_for_each_entry(notifier, &notifier_list, list)
		if (__v4l2_async_notifier_fwnode_has_async_subdev(
			    notifier, fwnode))
			return true;

	return false;
}

static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
{
	struct device *dev =
		notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
	struct v4l2_async_subdev *asd;
	int ret;
	int i;

	if (notifier->num_subdevs > V4L2_MAX_SUBDEVS)
		return -EINVAL;

	INIT_LIST_HEAD(&notifier->waiting);
	INIT_LIST_HEAD(&notifier->done);

	mutex_lock(&list_lock);

	for (i = 0; i < notifier->num_subdevs; i++) {
		asd = notifier->subdevs[i];

		switch (asd->match_type) {
		case V4L2_ASYNC_MATCH_CUSTOM:
		case V4L2_ASYNC_MATCH_DEVNAME:
		case V4L2_ASYNC_MATCH_I2C:
			break;
		case V4L2_ASYNC_MATCH_FWNODE:
			if (v4l2_async_notifier_fwnode_has_async_subdev(
				    notifier, asd->match.fwnode, i)) {
				dev_err(dev,
					"fwnode has already been registered or in notifier's subdev list\n");
				ret = -EEXIST;
				goto err_unlock;
			}
			break;
		default:
			dev_err(dev, "Invalid match type %u on %p\n",
				asd->match_type, asd);
			ret = -EINVAL;
			goto err_unlock;
		}
		list_add_tail(&asd->list, &notifier->waiting);
	}

	ret = v4l2_async_notifier_try_all_subdevs(notifier);
	if (ret < 0)
		goto err_unbind;

	ret = v4l2_async_notifier_try_complete(notifier);
	if (ret < 0)
		goto err_unbind;

	/* Keep also completed notifiers on the list */
	list_add(&notifier->list, &notifier_list);

	mutex_unlock(&list_lock);

	return 0;

err_unbind:
	/*
	 * On failure, unbind all sub-devices registered through this notifier.
	 */
	v4l2_async_notifier_unbind_all_subdevs(notifier);

err_unlock:
	mutex_unlock(&list_lock);

	return ret;
}

int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
				 struct v4l2_async_notifier *notifier)
{
	int ret;

	if (WARN_ON(!v4l2_dev || notifier->sd))
		return -EINVAL;

	notifier->v4l2_dev = v4l2_dev;

	ret = __v4l2_async_notifier_register(notifier);
	if (ret)
		notifier->v4l2_dev = NULL;

	return ret;
}
EXPORT_SYMBOL(v4l2_async_notifier_register);

int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
					struct v4l2_async_notifier *notifier)
{
	int ret;

	if (WARN_ON(!sd || notifier->v4l2_dev))
		return -EINVAL;

	notifier->sd = sd;

	ret = __v4l2_async_notifier_register(notifier);
	if (ret)
		notifier->sd = NULL;

	return ret;
}
EXPORT_SYMBOL(v4l2_async_subdev_notifier_register);

static void __v4l2_async_notifier_unregister(
	struct v4l2_async_notifier *notifier)
{
	if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
		return;

	v4l2_async_notifier_unbind_all_subdevs(notifier);

	notifier->sd = NULL;
	notifier->v4l2_dev = NULL;

	list_del(&notifier->list);
}

void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
{
	mutex_lock(&list_lock);

	__v4l2_async_notifier_unregister(notifier);

	mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_notifier_unregister);

void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
{
	unsigned int i;

	if (!notifier || !notifier->max_subdevs)
		return;

	for (i = 0; i < notifier->num_subdevs; i++) {
		struct v4l2_async_subdev *asd = notifier->subdevs[i];

		switch (asd->match_type) {
		case V4L2_ASYNC_MATCH_FWNODE:
			fwnode_handle_put(asd->match.fwnode);
			break;
		default:
			WARN_ON_ONCE(true);
			break;
		}

		kfree(asd);
	}

	notifier->max_subdevs = 0;
	notifier->num_subdevs = 0;

	kvfree(notifier->subdevs);
	notifier->subdevs = NULL;
}
EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);

int v4l2_async_register_subdev(struct v4l2_subdev *sd)
{
	struct v4l2_async_notifier *subdev_notifier;
	struct v4l2_async_notifier *notifier;
	int ret;

	/*
	 * No reference taken. The reference is held by the device
	 * (struct v4l2_subdev.dev), and async sub-device does not
	 * exist independently of the device at any point of time.
	 */
	if (!sd->fwnode && sd->dev)
		sd->fwnode = dev_fwnode(sd->dev);

	mutex_lock(&list_lock);

	INIT_LIST_HEAD(&sd->async_list);

	list_for_each_entry(notifier, &notifier_list, list) {
		struct v4l2_device *v4l2_dev =
			v4l2_async_notifier_find_v4l2_dev(notifier);
		struct v4l2_async_subdev *asd;

		if (!v4l2_dev)
			continue;

		asd = v4l2_async_find_match(notifier, sd);
		if (!asd)
			continue;

		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
		if (ret)
			goto err_unbind;

		ret = v4l2_async_notifier_try_complete(notifier);
		if (ret)
			goto err_unbind;

		goto out_unlock;
	}

	/* None matched, wait for hot-plugging */
	list_add(&sd->async_list, &subdev_list);

out_unlock:
	mutex_unlock(&list_lock);

	return 0;

err_unbind:
	/*
	 * Complete failed. Unbind the sub-devices bound through registering
	 * this async sub-device.
	 */
	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
	if (subdev_notifier)
		v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);

	if (sd->asd)
		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
	v4l2_async_cleanup(sd);

	mutex_unlock(&list_lock);

	return ret;
}
EXPORT_SYMBOL(v4l2_async_register_subdev);

void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
{
	mutex_lock(&list_lock);

	__v4l2_async_notifier_unregister(sd->subdev_notifier);
	v4l2_async_notifier_cleanup(sd->subdev_notifier);
	kfree(sd->subdev_notifier);
	sd->subdev_notifier = NULL;

	if (sd->asd) {
		struct v4l2_async_notifier *notifier = sd->notifier;

		list_add(&sd->asd->list, &notifier->waiting);

		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
	}

	v4l2_async_cleanup(sd);

	mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_unregister_subdev);