summaryrefslogtreecommitdiffstats
path: root/drivers/media/v4l2-core/v4l2-async.c
blob: 3ec323bd528b161e156284f35f43e006196fff71 (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
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
// SPDX-License-Identifier: GPL-2.0-only
/*
 * V4L2 asynchronous subdevice registration API
 *
 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 */

#include <linux/debugfs.h>
#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/seq_file.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>

#include "v4l2-subdev-priv.h"

static int v4l2_async_nf_call_bound(struct v4l2_async_notifier *n,
				    struct v4l2_subdev *subdev,
				    struct v4l2_async_connection *asc)
{
	if (!n->ops || !n->ops->bound)
		return 0;

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

static void v4l2_async_nf_call_unbind(struct v4l2_async_notifier *n,
				      struct v4l2_subdev *subdev,
				      struct v4l2_async_connection *asc)
{
	if (!n->ops || !n->ops->unbind)
		return;

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

static int v4l2_async_nf_call_complete(struct v4l2_async_notifier *n)
{
	if (!n->ops || !n->ops->complete)
		return 0;

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

static void v4l2_async_nf_call_destroy(struct v4l2_async_notifier *n,
				       struct v4l2_async_connection *asc)
{
	if (!n->ops || !n->ops->destroy)
		return;

	n->ops->destroy(asc);
}

static bool match_i2c(struct v4l2_async_notifier *notifier,
		      struct v4l2_subdev *sd,
		      struct v4l2_async_match_desc *match)
{
#if IS_ENABLED(CONFIG_I2C)
	struct i2c_client *client = i2c_verify_client(sd->dev);

	return client &&
		match->i2c.adapter_id == client->adapter->nr &&
		match->i2c.address == client->addr;
#else
	return false;
#endif
}

static struct device *notifier_dev(struct v4l2_async_notifier *notifier)
{
	if (notifier->sd)
		return notifier->sd->dev;

	if (notifier->v4l2_dev)
		return notifier->v4l2_dev->dev;

	return NULL;
}

static bool
match_fwnode_one(struct v4l2_async_notifier *notifier,
		 struct v4l2_subdev *sd, struct fwnode_handle *sd_fwnode,
		 struct v4l2_async_match_desc *match)
{
	struct fwnode_handle *asd_dev_fwnode;
	bool ret;

	dev_dbg(notifier_dev(notifier),
		"v4l2-async: fwnode match: need %pfw, trying %pfw\n",
		sd_fwnode, match->fwnode);

	if (sd_fwnode == match->fwnode) {
		dev_dbg(notifier_dev(notifier),
			"v4l2-async: direct match found\n");
		return true;
	}

	if (!fwnode_graph_is_endpoint(match->fwnode)) {
		dev_dbg(notifier_dev(notifier),
			"v4l2-async: direct match not found\n");
		return false;
	}

	asd_dev_fwnode = fwnode_graph_get_port_parent(match->fwnode);

	ret = sd_fwnode == asd_dev_fwnode;

	fwnode_handle_put(asd_dev_fwnode);

	dev_dbg(notifier_dev(notifier),
		"v4l2-async: device--endpoint match %sfound\n",
		ret ? "" : "not ");

	return ret;
}

static bool match_fwnode(struct v4l2_async_notifier *notifier,
			 struct v4l2_subdev *sd,
			 struct v4l2_async_match_desc *match)
{
	dev_dbg(notifier_dev(notifier),
		"v4l2-async: matching for notifier %pfw, sd fwnode %pfw\n",
		dev_fwnode(notifier_dev(notifier)), sd->fwnode);

	if (!list_empty(&sd->async_subdev_endpoint_list)) {
		struct v4l2_async_subdev_endpoint *ase;

		dev_dbg(sd->dev,
			"v4l2-async: endpoint fwnode list available, looking for %pfw\n",
			match->fwnode);

		list_for_each_entry(ase, &sd->async_subdev_endpoint_list,
				    async_subdev_endpoint_entry) {
			bool matched = ase->endpoint == match->fwnode;

			dev_dbg(sd->dev,
				"v4l2-async: endpoint-endpoint match %sfound with %pfw\n",
				matched ? "" : "not ", ase->endpoint);

			if (matched)
				return true;
		}

		dev_dbg(sd->dev, "async: no endpoint matched\n");

		return false;
	}

	if (match_fwnode_one(notifier, sd, sd->fwnode, match))
		return true;

	/* Also check the secondary fwnode. */
	if (IS_ERR_OR_NULL(sd->fwnode->secondary))
		return false;

	dev_dbg(notifier_dev(notifier),
		"v4l2-async: trying secondary fwnode match\n");

	return match_fwnode_one(notifier, sd, sd->fwnode->secondary, match);
}

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

static struct v4l2_async_connection *
v4l2_async_find_match(struct v4l2_async_notifier *notifier,
		      struct v4l2_subdev *sd)
{
	bool (*match)(struct v4l2_async_notifier *notifier,
		      struct v4l2_subdev *sd,
		      struct v4l2_async_match_desc *match);
	struct v4l2_async_connection *asc;

	list_for_each_entry(asc, &notifier->waiting_list, asc_entry) {
		/* bus_type has been verified valid before */
		switch (asc->match.type) {
		case V4L2_ASYNC_MATCH_TYPE_I2C:
			match = match_i2c;
			break;
		case V4L2_ASYNC_MATCH_TYPE_FWNODE:
			match = match_fwnode;
			break;
		default:
			/* Cannot happen, unless someone breaks us */
			WARN_ON(true);
			return NULL;
		}

		/* match cannot be NULL here */
		if (match(notifier, sd, &asc->match))
			return asc;
	}

	return NULL;
}

/* Compare two async match descriptors for equivalence */
static bool v4l2_async_match_equal(struct v4l2_async_match_desc *match1,
				   struct v4l2_async_match_desc *match2)
{
	if (match1->type != match2->type)
		return false;

	switch (match1->type) {
	case V4L2_ASYNC_MATCH_TYPE_I2C:
		return match1->i2c.adapter_id == match2->i2c.adapter_id &&
			match1->i2c.address == match2->i2c.address;
	case V4L2_ASYNC_MATCH_TYPE_FWNODE:
		return match1->fwnode == match2->fwnode;
	default:
		break;
	}

	return false;
}

/* 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, notifier_entry)
		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_nf_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_nf_can_complete(struct v4l2_async_notifier *notifier)
{
	struct v4l2_async_connection *asc;

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

	list_for_each_entry(asc, &notifier->done_list, asc_entry) {
		struct v4l2_async_notifier *subdev_notifier =
			v4l2_async_find_subdev_notifier(asc->sd);

		if (subdev_notifier &&
		    !v4l2_async_nf_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_nf_try_complete(struct v4l2_async_notifier *notifier)
{
	struct v4l2_async_notifier *__notifier = notifier;

	/* Quick check whether there are still more sub-devices here. */
	if (!list_empty(&notifier->waiting_list))
		return 0;

	if (notifier->sd)
		dev_dbg(notifier_dev(notifier),
			"v4l2-async: trying to complete\n");

	/* 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) {
		dev_dbg(notifier_dev(__notifier),
			"v4l2-async: V4L2 device not available\n");
		return 0;
	}

	/* Is everything ready? */
	if (!v4l2_async_nf_can_complete(notifier))
		return 0;

	dev_dbg(notifier_dev(__notifier), "v4l2-async: complete\n");

	return v4l2_async_nf_call_complete(notifier);
}

static int
v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier);

static int v4l2_async_create_ancillary_links(struct v4l2_async_notifier *n,
					     struct v4l2_subdev *sd)
{
	struct media_link *link = NULL;

#if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)

	if (sd->entity.function != MEDIA_ENT_F_LENS &&
	    sd->entity.function != MEDIA_ENT_F_FLASH)
		return 0;

	link = media_create_ancillary_link(&n->sd->entity, &sd->entity);

#endif

	return IS_ERR(link) ? PTR_ERR(link) : 0;
}

static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
				   struct v4l2_device *v4l2_dev,
				   struct v4l2_subdev *sd,
				   struct v4l2_async_connection *asc)
{
	struct v4l2_async_notifier *subdev_notifier;
	bool registered = false;
	int ret;

	if (list_empty(&sd->asc_list)) {
		ret = v4l2_device_register_subdev(v4l2_dev, sd);
		if (ret < 0)
			return ret;
		registered = true;
	}

	ret = v4l2_async_nf_call_bound(notifier, sd, asc);
	if (ret < 0) {
		if (asc->match.type == V4L2_ASYNC_MATCH_TYPE_FWNODE)
			dev_dbg(notifier_dev(notifier),
				"failed binding %pfw (%d)\n",
				asc->match.fwnode, ret);
		goto err_unregister_subdev;
	}

	if (registered) {
		/*
		 * Depending of the function of the entities involved, we may
		 * want to create links between them (for example between a
		 * sensor and its lens or between a sensor's source pad and the
		 * connected device's sink pad).
		 */
		ret = v4l2_async_create_ancillary_links(notifier, sd);
		if (ret) {
			if (asc->match.type == V4L2_ASYNC_MATCH_TYPE_FWNODE)
				dev_dbg(notifier_dev(notifier),
					"failed creating links for %pfw (%d)\n",
					asc->match.fwnode, ret);
			goto err_call_unbind;
		}
	}

	list_add(&asc->asc_subdev_entry, &sd->asc_list);
	asc->sd = sd;

	/* Move from the waiting list to notifier's done */
	list_move(&asc->asc_entry, &notifier->done_list);

	dev_dbg(notifier_dev(notifier), "v4l2-async: %s bound (ret %d)\n",
		dev_name(sd->dev), ret);

	/*
	 * 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_nf_try_all_subdevs(subdev_notifier);

err_call_unbind:
	v4l2_async_nf_call_unbind(notifier, sd, asc);
	list_del(&asc->asc_subdev_entry);

err_unregister_subdev:
	if (registered)
		v4l2_device_unregister_subdev(sd);

	return ret;
}

/* Test all async sub-devices in a notifier for a match. */
static int
v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier)
{
	struct v4l2_device *v4l2_dev =
		v4l2_async_nf_find_v4l2_dev(notifier);
	struct v4l2_subdev *sd;

	if (!v4l2_dev)
		return 0;

	dev_dbg(notifier_dev(notifier), "v4l2-async: trying all sub-devices\n");

again:
	list_for_each_entry(sd, &subdev_list, async_list) {
		struct v4l2_async_connection *asc;
		int ret;

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

		dev_dbg(notifier_dev(notifier),
			"v4l2-async: match found, subdev %s\n", sd->name);

		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asc);
		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_unbind_subdev_one(struct v4l2_async_notifier *notifier,
					 struct v4l2_async_connection *asc)
{
	list_move_tail(&asc->asc_entry, &notifier->waiting_list);
	if (list_is_singular(&asc->asc_subdev_entry)) {
		v4l2_async_nf_call_unbind(notifier, asc->sd, asc);
		v4l2_device_unregister_subdev(asc->sd);
		asc->sd = NULL;
	}
	list_del(&asc->asc_subdev_entry);
}

/* Unbind all sub-devices in the notifier tree. */
static void
v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
{
	struct v4l2_async_connection *asc, *asc_tmp;

	list_for_each_entry_safe(asc, asc_tmp, &notifier->done_list,
				 asc_entry) {
		struct v4l2_async_notifier *subdev_notifier =
			v4l2_async_find_subdev_notifier(asc->sd);

		if (subdev_notifier)
			v4l2_async_nf_unbind_all_subdevs(subdev_notifier);

		v4l2_async_unbind_subdev_one(notifier, asc);
	}

	notifier->parent = NULL;
}

/* See if an async sub-device can be found in a notifier's lists. */
static bool
v4l2_async_nf_has_async_match_entry(struct v4l2_async_notifier *notifier,
				    struct v4l2_async_match_desc *match)
{
	struct v4l2_async_connection *asc;

	list_for_each_entry(asc, &notifier->waiting_list, asc_entry)
		if (v4l2_async_match_equal(&asc->match, match))
			return true;

	list_for_each_entry(asc, &notifier->done_list, asc_entry)
		if (v4l2_async_match_equal(&asc->match, match))
			return true;

	return false;
}

/*
 * Find out whether an async sub-device was set up already or whether it exists
 * in a given notifier.
 */
static bool
v4l2_async_nf_has_async_match(struct v4l2_async_notifier *notifier,
			      struct v4l2_async_match_desc *match)
{
	struct list_head *heads[] = {
		&notifier->waiting_list,
		&notifier->done_list,
	};
	unsigned int i;

	lockdep_assert_held(&list_lock);

	/* Check that an asd is not being added more than once. */
	for (i = 0; i < ARRAY_SIZE(heads); i++) {
		struct v4l2_async_connection *asc;

		list_for_each_entry(asc, heads[i], asc_entry) {
			if (&asc->match == match)
				continue;
			if (v4l2_async_match_equal(&asc->match, match))
				return true;
		}
	}

	/* Check that an asc does not exist in other notifiers. */
	list_for_each_entry(notifier, &notifier_list, notifier_entry)
		if (v4l2_async_nf_has_async_match_entry(notifier, match))
			return true;

	return false;
}

static int v4l2_async_nf_match_valid(struct v4l2_async_notifier *notifier,
				     struct v4l2_async_match_desc *match)
{
	struct device *dev = notifier_dev(notifier);

	switch (match->type) {
	case V4L2_ASYNC_MATCH_TYPE_I2C:
	case V4L2_ASYNC_MATCH_TYPE_FWNODE:
		if (v4l2_async_nf_has_async_match(notifier, match)) {
			dev_dbg(dev, "v4l2-async: match descriptor already listed in a notifier\n");
			return -EEXIST;
		}
		break;
	default:
		dev_err(dev, "v4l2-async: Invalid match type %u on %p\n",
			match->type, match);
		return -EINVAL;
	}

	return 0;
}

void v4l2_async_nf_init(struct v4l2_async_notifier *notifier,
			struct v4l2_device *v4l2_dev)
{
	INIT_LIST_HEAD(&notifier->waiting_list);
	INIT_LIST_HEAD(&notifier->done_list);
	notifier->v4l2_dev = v4l2_dev;
}
EXPORT_SYMBOL(v4l2_async_nf_init);

void v4l2_async_subdev_nf_init(struct v4l2_async_notifier *notifier,
			       struct v4l2_subdev *sd)
{
	INIT_LIST_HEAD(&notifier->waiting_list);
	INIT_LIST_HEAD(&notifier->done_list);
	notifier->sd = sd;
}
EXPORT_SYMBOL_GPL(v4l2_async_subdev_nf_init);

static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
{
	struct v4l2_async_connection *asc;
	int ret;

	mutex_lock(&list_lock);

	list_for_each_entry(asc, &notifier->waiting_list, asc_entry) {
		ret = v4l2_async_nf_match_valid(notifier, &asc->match);
		if (ret)
			goto err_unlock;
	}

	ret = v4l2_async_nf_try_all_subdevs(notifier);
	if (ret < 0)
		goto err_unbind;

	ret = v4l2_async_nf_try_complete(notifier);
	if (ret < 0)
		goto err_unbind;

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

	mutex_unlock(&list_lock);

	return 0;

err_unbind:
	/*
	 * On failure, unbind all sub-devices registered through this notifier.
	 */
	v4l2_async_nf_unbind_all_subdevs(notifier);

err_unlock:
	mutex_unlock(&list_lock);

	return ret;
}

int v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
{
	int ret;

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

	ret = __v4l2_async_nf_register(notifier);
	if (ret)
		notifier->v4l2_dev = NULL;

	return ret;
}
EXPORT_SYMBOL(v4l2_async_nf_register);

static void
__v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
{
	if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
		return;

	v4l2_async_nf_unbind_all_subdevs(notifier);

	list_del(&notifier->notifier_entry);
}

void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
{
	mutex_lock(&list_lock);

	__v4l2_async_nf_unregister(notifier);

	mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_nf_unregister);

static void __v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
{
	struct v4l2_async_connection *asc, *tmp;

	if (!notifier || !notifier->waiting_list.next)
		return;

	WARN_ON(!list_empty(&notifier->done_list));

	list_for_each_entry_safe(asc, tmp, &notifier->waiting_list, asc_entry) {
		list_del(&asc->asc_entry);
		v4l2_async_nf_call_destroy(notifier, asc);

		if (asc->match.type == V4L2_ASYNC_MATCH_TYPE_FWNODE)
			fwnode_handle_put(asc->match.fwnode);

		kfree(asc);
	}

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

void v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
{
	mutex_lock(&list_lock);

	__v4l2_async_nf_cleanup(notifier);

	mutex_unlock(&list_lock);
}
EXPORT_SYMBOL_GPL(v4l2_async_nf_cleanup);

static void __v4l2_async_nf_add_connection(struct v4l2_async_notifier *notifier,
					   struct v4l2_async_connection *asc)
{
	mutex_lock(&list_lock);

	list_add_tail(&asc->asc_entry, &notifier->waiting_list);

	mutex_unlock(&list_lock);
}

struct v4l2_async_connection *
__v4l2_async_nf_add_fwnode(struct v4l2_async_notifier *notifier,
			   struct fwnode_handle *fwnode,
			   unsigned int asc_struct_size)
{
	struct v4l2_async_connection *asc;

	asc = kzalloc(asc_struct_size, GFP_KERNEL);
	if (!asc)
		return ERR_PTR(-ENOMEM);

	asc->notifier = notifier;
	asc->match.type = V4L2_ASYNC_MATCH_TYPE_FWNODE;
	asc->match.fwnode = fwnode_handle_get(fwnode);

	__v4l2_async_nf_add_connection(notifier, asc);

	return asc;
}
EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode);

struct v4l2_async_connection *
__v4l2_async_nf_add_fwnode_remote(struct v4l2_async_notifier *notif,
				  struct fwnode_handle *endpoint,
				  unsigned int asc_struct_size)
{
	struct v4l2_async_connection *asc;
	struct fwnode_handle *remote;

	remote = fwnode_graph_get_remote_endpoint(endpoint);
	if (!remote)
		return ERR_PTR(-ENOTCONN);

	asc = __v4l2_async_nf_add_fwnode(notif, remote, asc_struct_size);
	/*
	 * Calling __v4l2_async_nf_add_fwnode grabs a refcount,
	 * so drop the one we got in fwnode_graph_get_remote_port_parent.
	 */
	fwnode_handle_put(remote);
	return asc;
}
EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode_remote);

struct v4l2_async_connection *
__v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier, int adapter_id,
			unsigned short address, unsigned int asc_struct_size)
{
	struct v4l2_async_connection *asc;

	asc = kzalloc(asc_struct_size, GFP_KERNEL);
	if (!asc)
		return ERR_PTR(-ENOMEM);

	asc->notifier = notifier;
	asc->match.type = V4L2_ASYNC_MATCH_TYPE_I2C;
	asc->match.i2c.adapter_id = adapter_id;
	asc->match.i2c.address = address;

	__v4l2_async_nf_add_connection(notifier, asc);

	return asc;
}
EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_i2c);

int v4l2_async_subdev_endpoint_add(struct v4l2_subdev *sd,
				   struct fwnode_handle *fwnode)
{
	struct v4l2_async_subdev_endpoint *ase;

	ase = kmalloc(sizeof(*ase), GFP_KERNEL);
	if (!ase)
		return -ENOMEM;

	ase->endpoint = fwnode;
	list_add(&ase->async_subdev_endpoint_entry,
		 &sd->async_subdev_endpoint_list);

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_async_subdev_endpoint_add);

struct v4l2_async_connection *
v4l2_async_connection_unique(struct v4l2_subdev *sd)
{
	if (!list_is_singular(&sd->asc_list))
		return NULL;

	return list_first_entry(&sd->asc_list,
				struct v4l2_async_connection, asc_subdev_entry);
}
EXPORT_SYMBOL_GPL(v4l2_async_connection_unique);

int v4l2_async_register_subdev(struct v4l2_subdev *sd)
{
	struct v4l2_async_notifier *subdev_notifier;
	struct v4l2_async_notifier *notifier;
	struct v4l2_async_connection *asc;
	int ret;

	INIT_LIST_HEAD(&sd->asc_list);

	/*
	 * 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.
	 *
	 * The async sub-device shall always be registered for its device node,
	 * not the endpoint node.
	 */
	if (!sd->fwnode && sd->dev) {
		sd->fwnode = dev_fwnode(sd->dev);
	} else if (fwnode_graph_is_endpoint(sd->fwnode)) {
		dev_warn(sd->dev, "sub-device fwnode is an endpoint!\n");
		return -EINVAL;
	}

	mutex_lock(&list_lock);

	list_for_each_entry(notifier, &notifier_list, notifier_entry) {
		struct v4l2_device *v4l2_dev =
			v4l2_async_nf_find_v4l2_dev(notifier);

		if (!v4l2_dev)
			continue;

		while ((asc = v4l2_async_find_match(notifier, sd))) {
			ret = v4l2_async_match_notify(notifier, v4l2_dev, sd,
						      asc);
			if (ret)
				goto err_unbind;

			ret = v4l2_async_nf_try_complete(notifier);
			if (ret)
				goto err_unbind;
		}
	}

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

	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_nf_unbind_all_subdevs(subdev_notifier);

	if (asc)
		v4l2_async_unbind_subdev_one(notifier, asc);

	mutex_unlock(&list_lock);

	return ret;
}
EXPORT_SYMBOL(v4l2_async_register_subdev);

void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
{
	struct v4l2_async_connection *asc, *asc_tmp;

	if (!sd->async_list.next)
		return;

	v4l2_subdev_put_privacy_led(sd);

	mutex_lock(&list_lock);

	__v4l2_async_nf_unregister(sd->subdev_notifier);
	__v4l2_async_nf_cleanup(sd->subdev_notifier);
	kfree(sd->subdev_notifier);
	sd->subdev_notifier = NULL;

	if (sd->asc_list.next) {
		list_for_each_entry_safe(asc, asc_tmp, &sd->asc_list,
					 asc_subdev_entry) {
			v4l2_async_unbind_subdev_one(asc->notifier, asc);
		}
	}

	list_del(&sd->async_list);
	sd->async_list.next = NULL;

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

static void print_waiting_match(struct seq_file *s,
				struct v4l2_async_match_desc *match)
{
	switch (match->type) {
	case V4L2_ASYNC_MATCH_TYPE_I2C:
		seq_printf(s, " [i2c] dev=%d-%04x\n", match->i2c.adapter_id,
			   match->i2c.address);
		break;
	case V4L2_ASYNC_MATCH_TYPE_FWNODE: {
		struct fwnode_handle *devnode, *fwnode = match->fwnode;

		devnode = fwnode_graph_is_endpoint(fwnode) ?
			  fwnode_graph_get_port_parent(fwnode) :
			  fwnode_handle_get(fwnode);

		seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
			   devnode->dev ? dev_name(devnode->dev) : "nil",
			   fwnode);

		fwnode_handle_put(devnode);
		break;
	}
	}
}

static const char *
v4l2_async_nf_name(struct v4l2_async_notifier *notifier)
{
	if (notifier->v4l2_dev)
		return notifier->v4l2_dev->name;
	else if (notifier->sd)
		return notifier->sd->name;
	else
		return "nil";
}

static int pending_subdevs_show(struct seq_file *s, void *data)
{
	struct v4l2_async_notifier *notif;
	struct v4l2_async_connection *asc;

	mutex_lock(&list_lock);

	list_for_each_entry(notif, &notifier_list, notifier_entry) {
		seq_printf(s, "%s:\n", v4l2_async_nf_name(notif));
		list_for_each_entry(asc, &notif->waiting_list, asc_entry)
			print_waiting_match(s, &asc->match);
	}

	mutex_unlock(&list_lock);

	return 0;
}
DEFINE_SHOW_ATTRIBUTE(pending_subdevs);

static struct dentry *v4l2_async_debugfs_dir;

static int __init v4l2_async_init(void)
{
	v4l2_async_debugfs_dir = debugfs_create_dir("v4l2-async", NULL);
	debugfs_create_file("pending_async_subdevices", 0444,
			    v4l2_async_debugfs_dir, NULL,
			    &pending_subdevs_fops);

	return 0;
}

static void __exit v4l2_async_exit(void)
{
	debugfs_remove_recursive(v4l2_async_debugfs_dir);
}

subsys_initcall(v4l2_async_init);
module_exit(v4l2_async_exit);

MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
MODULE_AUTHOR("Ezequiel Garcia <ezequiel@collabora.com>");
MODULE_LICENSE("GPL");