summaryrefslogtreecommitdiff
path: root/sound/core/init.c
blob: 5377f94eb2111f844e1c439926f1a27bfb728fd4 (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
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Initialization routines
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/ctype.h>
#include <linux/pm.h>
#include <linux/debugfs.h>
#include <linux/completion.h>
#include <linux/interrupt.h>

#include <sound/core.h>
#include <sound/control.h>
#include <sound/info.h>

/* monitor files for graceful shutdown (hotplug) */
struct snd_monitor_file {
	struct file *file;
	const struct file_operations *disconnected_f_op;
	struct list_head shutdown_list;	/* still need to shutdown */
	struct list_head list;	/* link of monitor files */
};

static DEFINE_SPINLOCK(shutdown_lock);
static LIST_HEAD(shutdown_files);

static const struct file_operations snd_shutdown_f_ops;

/* locked for registering/using */
static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
static struct snd_card *snd_cards[SNDRV_CARDS];

static DEFINE_MUTEX(snd_card_mutex);

static char *slots[SNDRV_CARDS];
module_param_array(slots, charp, NULL, 0444);
MODULE_PARM_DESC(slots, "Module names assigned to the slots.");

/* return non-zero if the given index is reserved for the given
 * module via slots option
 */
static int module_slot_match(struct module *module, int idx)
{
	int match = 1;
#ifdef MODULE
	const char *s1, *s2;

	if (!module || !*module->name || !slots[idx])
		return 0;

	s1 = module->name;
	s2 = slots[idx];
	if (*s2 == '!') {
		match = 0; /* negative match */
		s2++;
	}
	/* compare module name strings
	 * hyphens are handled as equivalent with underscore
	 */
	for (;;) {
		char c1 = *s1++;
		char c2 = *s2++;
		if (c1 == '-')
			c1 = '_';
		if (c2 == '-')
			c2 = '_';
		if (c1 != c2)
			return !match;
		if (!c1)
			break;
	}
#endif /* MODULE */
	return match;
}

#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
#endif

static int check_empty_slot(struct module *module, int slot)
{
	return !slots[slot] || !*slots[slot];
}

/* return an empty slot number (>= 0) found in the given bitmask @mask.
 * @mask == -1 == 0xffffffff means: take any free slot up to 32
 * when no slot is available, return the original @mask as is.
 */
static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
				 struct module *module)
{
	int slot;

	for (slot = 0; slot < SNDRV_CARDS; slot++) {
		if (slot < 32 && !(mask & (1U << slot)))
			continue;
		if (!test_bit(slot, snd_cards_lock)) {
			if (check(module, slot))
				return slot; /* found */
		}
	}
	return mask; /* unchanged */
}

/* the default release callback set in snd_device_initialize() below;
 * this is just NOP for now, as almost all jobs are already done in
 * dev_free callback of snd_device chain instead.
 */
static void default_release(struct device *dev)
{
}

/**
 * snd_device_initialize - Initialize struct device for sound devices
 * @dev: device to initialize
 * @card: card to assign, optional
 */
void snd_device_initialize(struct device *dev, struct snd_card *card)
{
	device_initialize(dev);
	if (card)
		dev->parent = &card->card_dev;
	dev->class = sound_class;
	dev->release = default_release;
}
EXPORT_SYMBOL_GPL(snd_device_initialize);

static int snd_card_init(struct snd_card *card, struct device *parent,
			 int idx, const char *xid, struct module *module,
			 size_t extra_size);
static int snd_card_do_free(struct snd_card *card);
static const struct attribute_group card_dev_attr_group;

static void release_card_device(struct device *dev)
{
	snd_card_do_free(dev_to_snd_card(dev));
}

/**
 *  snd_card_new - create and initialize a soundcard structure
 *  @parent: the parent device object
 *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 *  @xid: card identification (ASCII string)
 *  @module: top level module for locking
 *  @extra_size: allocate this extra size after the main soundcard structure
 *  @card_ret: the pointer to store the created card instance
 *
 *  The function allocates snd_card instance via kzalloc with the given
 *  space for the driver to use freely.  The allocated struct is stored
 *  in the given card_ret pointer.
 *
 *  Return: Zero if successful or a negative error code.
 */
int snd_card_new(struct device *parent, int idx, const char *xid,
		    struct module *module, int extra_size,
		    struct snd_card **card_ret)
{
	struct snd_card *card;
	int err;

	if (snd_BUG_ON(!card_ret))
		return -EINVAL;
	*card_ret = NULL;

	if (extra_size < 0)
		extra_size = 0;
	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
	if (!card)
		return -ENOMEM;

	err = snd_card_init(card, parent, idx, xid, module, extra_size);
	if (err < 0)
		return err; /* card is freed by error handler */

	*card_ret = card;
	return 0;
}
EXPORT_SYMBOL(snd_card_new);

static void __snd_card_release(struct device *dev, void *data)
{
	snd_card_free(data);
}

/**
 * snd_devm_card_new - managed snd_card object creation
 * @parent: the parent device object
 * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 * @xid: card identification (ASCII string)
 * @module: top level module for locking
 * @extra_size: allocate this extra size after the main soundcard structure
 * @card_ret: the pointer to store the created card instance
 *
 * This function works like snd_card_new() but manages the allocated resource
 * via devres, i.e. you don't need to free explicitly.
 *
 * When a snd_card object is created with this function and registered via
 * snd_card_register(), the very first devres action to call snd_card_free()
 * is added automatically.  In that way, the resource disconnection is assured
 * at first, then released in the expected order.
 *
 * If an error happens at the probe before snd_card_register() is called and
 * there have been other devres resources, you'd need to free the card manually
 * via snd_card_free() call in the error; otherwise it may lead to UAF due to
 * devres call orders.  You can use snd_card_free_on_error() helper for
 * handling it more easily.
 *
 * Return: zero if successful, or a negative error code
 */
int snd_devm_card_new(struct device *parent, int idx, const char *xid,
		      struct module *module, size_t extra_size,
		      struct snd_card **card_ret)
{
	struct snd_card *card;
	int err;

	*card_ret = NULL;
	card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
			    GFP_KERNEL);
	if (!card)
		return -ENOMEM;
	card->managed = true;
	err = snd_card_init(card, parent, idx, xid, module, extra_size);
	if (err < 0) {
		devres_free(card); /* in managed mode, we need to free manually */
		return err;
	}

	devres_add(parent, card);
	*card_ret = card;
	return 0;
}
EXPORT_SYMBOL_GPL(snd_devm_card_new);

/**
 * snd_card_free_on_error - a small helper for handling devm probe errors
 * @dev: the managed device object
 * @ret: the return code from the probe callback
 *
 * This function handles the explicit snd_card_free() call at the error from
 * the probe callback.  It's just a small helper for simplifying the error
 * handling with the managed devices.
 *
 * Return: zero if successful, or a negative error code
 */
int snd_card_free_on_error(struct device *dev, int ret)
{
	struct snd_card *card;

	if (!ret)
		return 0;
	card = devres_find(dev, __snd_card_release, NULL, NULL);
	if (card)
		snd_card_free(card);
	return ret;
}
EXPORT_SYMBOL_GPL(snd_card_free_on_error);

static int snd_card_init(struct snd_card *card, struct device *parent,
			 int idx, const char *xid, struct module *module,
			 size_t extra_size)
{
	int err;
#ifdef CONFIG_SND_DEBUG
	char name[8];
#endif

	if (extra_size > 0)
		card->private_data = (char *)card + sizeof(struct snd_card);
	if (xid)
		strscpy(card->id, xid, sizeof(card->id));
	err = 0;
	mutex_lock(&snd_card_mutex);
	if (idx < 0) /* first check the matching module-name slot */
		idx = get_slot_from_bitmask(idx, module_slot_match, module);
	if (idx < 0) /* if not matched, assign an empty slot */
		idx = get_slot_from_bitmask(idx, check_empty_slot, module);
	if (idx < 0)
		err = -ENODEV;
	else if (idx < snd_ecards_limit) {
		if (test_bit(idx, snd_cards_lock))
			err = -EBUSY;	/* invalid */
	} else if (idx >= SNDRV_CARDS)
		err = -ENODEV;
	if (err < 0) {
		mutex_unlock(&snd_card_mutex);
		dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
			 idx, snd_ecards_limit - 1, err);
		if (!card->managed)
			kfree(card); /* manually free here, as no destructor called */
		return err;
	}
	set_bit(idx, snd_cards_lock);		/* lock it */
	if (idx >= snd_ecards_limit)
		snd_ecards_limit = idx + 1; /* increase the limit */
	mutex_unlock(&snd_card_mutex);
	card->dev = parent;
	card->number = idx;
#ifdef MODULE
	WARN_ON(!module);
	card->module = module;
#endif
	INIT_LIST_HEAD(&card->devices);
	init_rwsem(&card->controls_rwsem);
	rwlock_init(&card->ctl_files_rwlock);
	INIT_LIST_HEAD(&card->controls);
	INIT_LIST_HEAD(&card->ctl_files);
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
	xa_init(&card->ctl_numids);
	xa_init(&card->ctl_hash);
#endif
	spin_lock_init(&card->files_lock);
	INIT_LIST_HEAD(&card->files_list);
	mutex_init(&card->memory_mutex);
#ifdef CONFIG_PM
	init_waitqueue_head(&card->power_sleep);
	init_waitqueue_head(&card->power_ref_sleep);
	atomic_set(&card->power_ref, 0);
#endif
	init_waitqueue_head(&card->remove_sleep);
	card->sync_irq = -1;

	device_initialize(&card->card_dev);
	card->card_dev.parent = parent;
	card->card_dev.class = sound_class;
	card->card_dev.release = release_card_device;
	card->card_dev.groups = card->dev_groups;
	card->dev_groups[0] = &card_dev_attr_group;
	err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
	if (err < 0)
		goto __error;

	snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
		 dev_driver_string(card->dev), dev_name(&card->card_dev));

	/* the control interface cannot be accessed from the user space until */
	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
	err = snd_ctl_create(card);
	if (err < 0) {
		dev_err(parent, "unable to register control minors\n");
		goto __error;
	}
	err = snd_info_card_create(card);
	if (err < 0) {
		dev_err(parent, "unable to create card info\n");
		goto __error_ctl;
	}

#ifdef CONFIG_SND_DEBUG
	sprintf(name, "card%d", idx);
	card->debugfs_root = debugfs_create_dir(name, sound_debugfs_root);
#endif
	return 0;

      __error_ctl:
	snd_device_free_all(card);
      __error:
	put_device(&card->card_dev);
  	return err;
}

/**
 * snd_card_ref - Get the card object from the index
 * @idx: the card index
 *
 * Returns a card object corresponding to the given index or NULL if not found.
 * Release the object via snd_card_unref().
 *
 * Return: a card object or NULL
 */
struct snd_card *snd_card_ref(int idx)
{
	struct snd_card *card;

	mutex_lock(&snd_card_mutex);
	card = snd_cards[idx];
	if (card)
		get_device(&card->card_dev);
	mutex_unlock(&snd_card_mutex);
	return card;
}
EXPORT_SYMBOL_GPL(snd_card_ref);

/* return non-zero if a card is already locked */
int snd_card_locked(int card)
{
	int locked;

	mutex_lock(&snd_card_mutex);
	locked = test_bit(card, snd_cards_lock);
	mutex_unlock(&snd_card_mutex);
	return locked;
}

static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
{
	return -ENODEV;
}

static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
				   size_t count, loff_t *offset)
{
	return -ENODEV;
}

static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
				    size_t count, loff_t *offset)
{
	return -ENODEV;
}

static int snd_disconnect_release(struct inode *inode, struct file *file)
{
	struct snd_monitor_file *df = NULL, *_df;

	spin_lock(&shutdown_lock);
	list_for_each_entry(_df, &shutdown_files, shutdown_list) {
		if (_df->file == file) {
			df = _df;
			list_del_init(&df->shutdown_list);
			break;
		}
	}
	spin_unlock(&shutdown_lock);

	if (likely(df)) {
		if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
			df->disconnected_f_op->fasync(-1, file, 0);
		return df->disconnected_f_op->release(inode, file);
	}

	panic("%s(%p, %p) failed!", __func__, inode, file);
}

static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
{
	return EPOLLERR | EPOLLNVAL;
}

static long snd_disconnect_ioctl(struct file *file,
				 unsigned int cmd, unsigned long arg)
{
	return -ENODEV;
}

static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
{
	return -ENODEV;
}

static int snd_disconnect_fasync(int fd, struct file *file, int on)
{
	return -ENODEV;
}

static const struct file_operations snd_shutdown_f_ops =
{
	.owner = 	THIS_MODULE,
	.llseek =	snd_disconnect_llseek,
	.read = 	snd_disconnect_read,
	.write =	snd_disconnect_write,
	.release =	snd_disconnect_release,
	.poll =		snd_disconnect_poll,
	.unlocked_ioctl = snd_disconnect_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = snd_disconnect_ioctl,
#endif
	.mmap =		snd_disconnect_mmap,
	.fasync =	snd_disconnect_fasync
};

/**
 *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 *  @card: soundcard structure
 *
 *  Disconnects all APIs from the file-operations (user space).
 *
 *  Return: Zero, otherwise a negative error code.
 *
 *  Note: The current implementation replaces all active file->f_op with special
 *        dummy file operations (they do nothing except release).
 */
int snd_card_disconnect(struct snd_card *card)
{
	struct snd_monitor_file *mfile;

	if (!card)
		return -EINVAL;

	spin_lock(&card->files_lock);
	if (card->shutdown) {
		spin_unlock(&card->files_lock);
		return 0;
	}
	card->shutdown = 1;

	/* replace file->f_op with special dummy operations */
	list_for_each_entry(mfile, &card->files_list, list) {
		/* it's critical part, use endless loop */
		/* we have no room to fail */
		mfile->disconnected_f_op = mfile->file->f_op;

		spin_lock(&shutdown_lock);
		list_add(&mfile->shutdown_list, &shutdown_files);
		spin_unlock(&shutdown_lock);

		mfile->file->f_op = &snd_shutdown_f_ops;
		fops_get(mfile->file->f_op);
	}
	spin_unlock(&card->files_lock);	

	/* notify all connected devices about disconnection */
	/* at this point, they cannot respond to any calls except release() */

#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
#endif

	/* notify all devices that we are disconnected */
	snd_device_disconnect_all(card);

	if (card->sync_irq > 0)
		synchronize_irq(card->sync_irq);

	snd_info_card_disconnect(card);
	if (card->registered) {
		device_del(&card->card_dev);
		card->registered = false;
	}

	/* disable fops (user space) operations for ALSA API */
	mutex_lock(&snd_card_mutex);
	snd_cards[card->number] = NULL;
	clear_bit(card->number, snd_cards_lock);
	mutex_unlock(&snd_card_mutex);

#ifdef CONFIG_PM
	wake_up(&card->power_sleep);
	snd_power_sync_ref(card);
#endif
	return 0;	
}
EXPORT_SYMBOL(snd_card_disconnect);

/**
 * snd_card_disconnect_sync - disconnect card and wait until files get closed
 * @card: card object to disconnect
 *
 * This calls snd_card_disconnect() for disconnecting all belonging components
 * and waits until all pending files get closed.
 * It assures that all accesses from user-space finished so that the driver
 * can release its resources gracefully.
 */
void snd_card_disconnect_sync(struct snd_card *card)
{
	int err;

	err = snd_card_disconnect(card);
	if (err < 0) {
		dev_err(card->dev,
			"snd_card_disconnect error (%d), skipping sync\n",
			err);
		return;
	}

	spin_lock_irq(&card->files_lock);
	wait_event_lock_irq(card->remove_sleep,
			    list_empty(&card->files_list),
			    card->files_lock);
	spin_unlock_irq(&card->files_lock);
}
EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);

static int snd_card_do_free(struct snd_card *card)
{
	card->releasing = true;
#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
#endif
	snd_device_free_all(card);
	if (card->private_free)
		card->private_free(card);
	if (snd_info_card_free(card) < 0) {
		dev_warn(card->dev, "unable to free card info\n");
		/* Not fatal error */
	}
#ifdef CONFIG_SND_DEBUG
	debugfs_remove(card->debugfs_root);
	card->debugfs_root = NULL;
#endif
	if (card->release_completion)
		complete(card->release_completion);
	if (!card->managed)
		kfree(card);
	return 0;
}

/**
 * snd_card_free_when_closed - Disconnect the card, free it later eventually
 * @card: soundcard structure
 *
 * Unlike snd_card_free(), this function doesn't try to release the card
 * resource immediately, but tries to disconnect at first.  When the card
 * is still in use, the function returns before freeing the resources.
 * The card resources will be freed when the refcount gets to zero.
 *
 * Return: zero if successful, or a negative error code
 */
int snd_card_free_when_closed(struct snd_card *card)
{
	int ret = snd_card_disconnect(card);
	if (ret)
		return ret;
	put_device(&card->card_dev);
	return 0;
}
EXPORT_SYMBOL(snd_card_free_when_closed);

/**
 * snd_card_free - frees given soundcard structure
 * @card: soundcard structure
 *
 * This function releases the soundcard structure and the all assigned
 * devices automatically.  That is, you don't have to release the devices
 * by yourself.
 *
 * This function waits until the all resources are properly released.
 *
 * Return: Zero. Frees all associated devices and frees the control
 * interface associated to given soundcard.
 */
int snd_card_free(struct snd_card *card)
{
	DECLARE_COMPLETION_ONSTACK(released);
	int ret;

	/* The call of snd_card_free() is allowed from various code paths;
	 * a manual call from the driver and the call via devres_free, and
	 * we need to avoid double-free. Moreover, the release via devres
	 * may call snd_card_free() twice due to its nature, we need to have
	 * the check here at the beginning.
	 */
	if (card->releasing)
		return 0;

	card->release_completion = &released;
	ret = snd_card_free_when_closed(card);
	if (ret)
		return ret;
	/* wait, until all devices are ready for the free operation */
	wait_for_completion(&released);

	return 0;
}
EXPORT_SYMBOL(snd_card_free);

/* retrieve the last word of shortname or longname */
static const char *retrieve_id_from_card_name(const char *name)
{
	const char *spos = name;

	while (*name) {
		if (isspace(*name) && isalnum(name[1]))
			spos = name + 1;
		name++;
	}
	return spos;
}

/* return true if the given id string doesn't conflict any other card ids */
static bool card_id_ok(struct snd_card *card, const char *id)
{
	int i;
	if (!snd_info_check_reserved_words(id))
		return false;
	for (i = 0; i < snd_ecards_limit; i++) {
		if (snd_cards[i] && snd_cards[i] != card &&
		    !strcmp(snd_cards[i]->id, id))
			return false;
	}
	return true;
}

/* copy to card->id only with valid letters from nid */
static void copy_valid_id_string(struct snd_card *card, const char *src,
				 const char *nid)
{
	char *id = card->id;

	while (*nid && !isalnum(*nid))
		nid++;
	if (isdigit(*nid))
		*id++ = isalpha(*src) ? *src : 'D';
	while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
		if (isalnum(*nid))
			*id++ = *nid;
		nid++;
	}
	*id = 0;
}

/* Set card->id from the given string
 * If the string conflicts with other ids, add a suffix to make it unique.
 */
static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
				    const char *nid)
{
	int len, loops;
	bool is_default = false;
	char *id;
	
	copy_valid_id_string(card, src, nid);
	id = card->id;

 again:
	/* use "Default" for obviously invalid strings
	 * ("card" conflicts with proc directories)
	 */
	if (!*id || !strncmp(id, "card", 4)) {
		strcpy(id, "Default");
		is_default = true;
	}

	len = strlen(id);
	for (loops = 0; loops < SNDRV_CARDS; loops++) {
		char *spos;
		char sfxstr[5]; /* "_012" */
		int sfxlen;

		if (card_id_ok(card, id))
			return; /* OK */

		/* Add _XYZ suffix */
		sprintf(sfxstr, "_%X", loops + 1);
		sfxlen = strlen(sfxstr);
		if (len + sfxlen >= sizeof(card->id))
			spos = id + sizeof(card->id) - sfxlen - 1;
		else
			spos = id + len;
		strcpy(spos, sfxstr);
	}
	/* fallback to the default id */
	if (!is_default) {
		*id = 0;
		goto again;
	}
	/* last resort... */
	dev_err(card->dev, "unable to set card id (%s)\n", id);
	if (card->proc_root->name)
		strscpy(card->id, card->proc_root->name, sizeof(card->id));
}

/**
 *  snd_card_set_id - set card identification name
 *  @card: soundcard structure
 *  @nid: new identification string
 *
 *  This function sets the card identification and checks for name
 *  collisions.
 */
void snd_card_set_id(struct snd_card *card, const char *nid)
{
	/* check if user specified own card->id */
	if (card->id[0] != '\0')
		return;
	mutex_lock(&snd_card_mutex);
	snd_card_set_id_no_lock(card, nid, nid);
	mutex_unlock(&snd_card_mutex);
}
EXPORT_SYMBOL(snd_card_set_id);

static ssize_t id_show(struct device *dev,
		       struct device_attribute *attr, char *buf)
{
	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
	return sysfs_emit(buf, "%s\n", card->id);
}

static ssize_t id_store(struct device *dev, struct device_attribute *attr,
			const char *buf, size_t count)
{
	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
	char buf1[sizeof(card->id)];
	size_t copy = count > sizeof(card->id) - 1 ?
					sizeof(card->id) - 1 : count;
	size_t idx;
	int c;

	for (idx = 0; idx < copy; idx++) {
		c = buf[idx];
		if (!isalnum(c) && c != '_' && c != '-')
			return -EINVAL;
	}
	memcpy(buf1, buf, copy);
	buf1[copy] = '\0';
	mutex_lock(&snd_card_mutex);
	if (!card_id_ok(NULL, buf1)) {
		mutex_unlock(&snd_card_mutex);
		return -EEXIST;
	}
	strcpy(card->id, buf1);
	snd_info_card_id_change(card);
	mutex_unlock(&snd_card_mutex);

	return count;
}

static DEVICE_ATTR_RW(id);

static ssize_t number_show(struct device *dev,
			   struct device_attribute *attr, char *buf)
{
	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
	return sysfs_emit(buf, "%i\n", card->number);
}

static DEVICE_ATTR_RO(number);

static struct attribute *card_dev_attrs[] = {
	&dev_attr_id.attr,
	&dev_attr_number.attr,
	NULL
};

static const struct attribute_group card_dev_attr_group = {
	.attrs	= card_dev_attrs,
};

/**
 * snd_card_add_dev_attr - Append a new sysfs attribute group to card
 * @card: card instance
 * @group: attribute group to append
 *
 * Return: zero if successful, or a negative error code
 */
int snd_card_add_dev_attr(struct snd_card *card,
			  const struct attribute_group *group)
{
	int i;

	/* loop for (arraysize-1) here to keep NULL at the last entry */
	for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
		if (!card->dev_groups[i]) {
			card->dev_groups[i] = group;
			return 0;
		}
	}

	dev_err(card->dev, "Too many groups assigned\n");
	return -ENOSPC;
}
EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);

static void trigger_card_free(void *data)
{
	snd_card_free(data);
}

/**
 *  snd_card_register - register the soundcard
 *  @card: soundcard structure
 *
 *  This function registers all the devices assigned to the soundcard.
 *  Until calling this, the ALSA control interface is blocked from the
 *  external accesses.  Thus, you should call this function at the end
 *  of the initialization of the card.
 *
 *  Return: Zero otherwise a negative error code if the registration failed.
 */
int snd_card_register(struct snd_card *card)
{
	int err;

	if (snd_BUG_ON(!card))
		return -EINVAL;

	if (!card->registered) {
		err = device_add(&card->card_dev);
		if (err < 0)
			return err;
		card->registered = true;
	} else {
		if (card->managed)
			devm_remove_action(card->dev, trigger_card_free, card);
	}

	if (card->managed) {
		err = devm_add_action(card->dev, trigger_card_free, card);
		if (err < 0)
			return err;
	}

	err = snd_device_register_all(card);
	if (err < 0)
		return err;
	mutex_lock(&snd_card_mutex);
	if (snd_cards[card->number]) {
		/* already registered */
		mutex_unlock(&snd_card_mutex);
		return snd_info_card_register(card); /* register pending info */
	}
	if (*card->id) {
		/* make a unique id name from the given string */
		char tmpid[sizeof(card->id)];
		memcpy(tmpid, card->id, sizeof(card->id));
		snd_card_set_id_no_lock(card, tmpid, tmpid);
	} else {
		/* create an id from either shortname or longname */
		const char *src;
		src = *card->shortname ? card->shortname : card->longname;
		snd_card_set_id_no_lock(card, src,
					retrieve_id_from_card_name(src));
	}
	snd_cards[card->number] = card;
	mutex_unlock(&snd_card_mutex);
	err = snd_info_card_register(card);
	if (err < 0)
		return err;

#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
#endif
	return 0;
}
EXPORT_SYMBOL(snd_card_register);

#ifdef CONFIG_SND_PROC_FS
static void snd_card_info_read(struct snd_info_entry *entry,
			       struct snd_info_buffer *buffer)
{
	int idx, count;
	struct snd_card *card;

	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
		mutex_lock(&snd_card_mutex);
		card = snd_cards[idx];
		if (card) {
			count++;
			snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
					idx,
					card->id,
					card->driver,
					card->shortname);
			snd_iprintf(buffer, "                      %s\n",
					card->longname);
		}
		mutex_unlock(&snd_card_mutex);
	}
	if (!count)
		snd_iprintf(buffer, "--- no soundcards ---\n");
}

#ifdef CONFIG_SND_OSSEMUL
void snd_card_info_read_oss(struct snd_info_buffer *buffer)
{
	int idx, count;
	struct snd_card *card;

	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
		mutex_lock(&snd_card_mutex);
		card = snd_cards[idx];
		if (card) {
			count++;
			snd_iprintf(buffer, "%s\n", card->longname);
		}
		mutex_unlock(&snd_card_mutex);
	}
	if (!count) {
		snd_iprintf(buffer, "--- no soundcards ---\n");
	}
}

#endif

#ifdef MODULE
static void snd_card_module_info_read(struct snd_info_entry *entry,
				      struct snd_info_buffer *buffer)
{
	int idx;
	struct snd_card *card;

	for (idx = 0; idx < SNDRV_CARDS; idx++) {
		mutex_lock(&snd_card_mutex);
		card = snd_cards[idx];
		if (card)
			snd_iprintf(buffer, "%2i %s\n",
				    idx, card->module->name);
		mutex_unlock(&snd_card_mutex);
	}
}
#endif

int __init snd_card_info_init(void)
{
	struct snd_info_entry *entry;

	entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
	if (! entry)
		return -ENOMEM;
	entry->c.text.read = snd_card_info_read;
	if (snd_info_register(entry) < 0)
		return -ENOMEM; /* freed in error path */

#ifdef MODULE
	entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
	if (!entry)
		return -ENOMEM;
	entry->c.text.read = snd_card_module_info_read;
	if (snd_info_register(entry) < 0)
		return -ENOMEM; /* freed in error path */
#endif

	return 0;
}
#endif /* CONFIG_SND_PROC_FS */

/**
 *  snd_component_add - add a component string
 *  @card: soundcard structure
 *  @component: the component id string
 *
 *  This function adds the component id string to the supported list.
 *  The component can be referred from the alsa-lib.
 *
 *  Return: Zero otherwise a negative error code.
 */
  
int snd_component_add(struct snd_card *card, const char *component)
{
	char *ptr;
	int len = strlen(component);

	ptr = strstr(card->components, component);
	if (ptr != NULL) {
		if (ptr[len] == '\0' || ptr[len] == ' ')	/* already there */
			return 1;
	}
	if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
		snd_BUG();
		return -ENOMEM;
	}
	if (card->components[0] != '\0')
		strcat(card->components, " ");
	strcat(card->components, component);
	return 0;
}
EXPORT_SYMBOL(snd_component_add);

/**
 *  snd_card_file_add - add the file to the file list of the card
 *  @card: soundcard structure
 *  @file: file pointer
 *
 *  This function adds the file to the file linked-list of the card.
 *  This linked-list is used to keep tracking the connection state,
 *  and to avoid the release of busy resources by hotplug.
 *
 *  Return: zero or a negative error code.
 */
int snd_card_file_add(struct snd_card *card, struct file *file)
{
	struct snd_monitor_file *mfile;

	mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
	if (mfile == NULL)
		return -ENOMEM;
	mfile->file = file;
	mfile->disconnected_f_op = NULL;
	INIT_LIST_HEAD(&mfile->shutdown_list);
	spin_lock(&card->files_lock);
	if (card->shutdown) {
		spin_unlock(&card->files_lock);
		kfree(mfile);
		return -ENODEV;
	}
	list_add(&mfile->list, &card->files_list);
	get_device(&card->card_dev);
	spin_unlock(&card->files_lock);
	return 0;
}
EXPORT_SYMBOL(snd_card_file_add);

/**
 *  snd_card_file_remove - remove the file from the file list
 *  @card: soundcard structure
 *  @file: file pointer
 *
 *  This function removes the file formerly added to the card via
 *  snd_card_file_add() function.
 *  If all files are removed and snd_card_free_when_closed() was
 *  called beforehand, it processes the pending release of
 *  resources.
 *
 *  Return: Zero or a negative error code.
 */
int snd_card_file_remove(struct snd_card *card, struct file *file)
{
	struct snd_monitor_file *mfile, *found = NULL;

	spin_lock(&card->files_lock);
	list_for_each_entry(mfile, &card->files_list, list) {
		if (mfile->file == file) {
			list_del(&mfile->list);
			spin_lock(&shutdown_lock);
			list_del(&mfile->shutdown_list);
			spin_unlock(&shutdown_lock);
			if (mfile->disconnected_f_op)
				fops_put(mfile->disconnected_f_op);
			found = mfile;
			break;
		}
	}
	if (list_empty(&card->files_list))
		wake_up_all(&card->remove_sleep);
	spin_unlock(&card->files_lock);
	if (!found) {
		dev_err(card->dev, "card file remove problem (%p)\n", file);
		return -ENOENT;
	}
	kfree(found);
	put_device(&card->card_dev);
	return 0;
}
EXPORT_SYMBOL(snd_card_file_remove);

#ifdef CONFIG_PM
/**
 * snd_power_ref_and_wait - wait until the card gets powered up
 * @card: soundcard structure
 *
 * Take the power_ref reference count of the given card, and
 * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
 * The refcount is down again while sleeping until power-up, hence this
 * function can be used for syncing the floating control ops accesses,
 * typically around calling control ops.
 *
 * The caller needs to pull down the refcount via snd_power_unref() later
 * no matter whether the error is returned from this function or not.
 *
 * Return: Zero if successful, or a negative error code.
 */
int snd_power_ref_and_wait(struct snd_card *card)
{
	snd_power_ref(card);
	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
		return 0;
	wait_event_cmd(card->power_sleep,
		       card->shutdown ||
		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
		       snd_power_unref(card), snd_power_ref(card));
	return card->shutdown ? -ENODEV : 0;
}
EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);

/**
 * snd_power_wait - wait until the card gets powered up (old form)
 * @card: soundcard structure
 *
 * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
 *
 * Return: Zero if successful, or a negative error code.
 */
int snd_power_wait(struct snd_card *card)
{
	int ret;

	ret = snd_power_ref_and_wait(card);
	snd_power_unref(card);
	return ret;
}
EXPORT_SYMBOL(snd_power_wait);
#endif /* CONFIG_PM */