1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Initialization routines
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5 */
6
7#include <linux/init.h>
8#include <linux/sched.h>
9#include <linux/module.h>
10#include <linux/device.h>
11#include <linux/file.h>
12#include <linux/slab.h>
13#include <linux/time.h>
14#include <linux/ctype.h>
15#include <linux/pm.h>
16#include <linux/debugfs.h>
17#include <linux/completion.h>
18#include <linux/interrupt.h>
19
20#include <sound/core.h>
21#include <sound/control.h>
22#include <sound/info.h>
23
24/* monitor files for graceful shutdown (hotplug) */
25struct snd_monitor_file {
26 struct file *file;
27 const struct file_operations *disconnected_f_op;
28 struct list_head shutdown_list; /* still need to shutdown */
29 struct list_head list; /* link of monitor files */
30};
31
32static DEFINE_SPINLOCK(shutdown_lock);
33static LIST_HEAD(shutdown_files);
34
35static const struct file_operations snd_shutdown_f_ops;
36
37/* locked for registering/using */
38static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
39static struct snd_card *snd_cards[SNDRV_CARDS];
40
41static DEFINE_MUTEX(snd_card_mutex);
42
43static char *slots[SNDRV_CARDS];
44module_param_array(slots, charp, NULL, 0444);
45MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
46
47/* return non-zero if the given index is reserved for the given
48 * module via slots option
49 */
50static int module_slot_match(struct module *module, int idx)
51{
52 int match = 1;
53#ifdef MODULE
54 const char *s1, *s2;
55
56 if (!module || !*module->name || !slots[idx])
57 return 0;
58
59 s1 = module->name;
60 s2 = slots[idx];
61 if (*s2 == '!') {
62 match = 0; /* negative match */
63 s2++;
64 }
65 /* compare module name strings
66 * hyphens are handled as equivalent with underscore
67 */
68 for (;;) {
69 char c1 = *s1++;
70 char c2 = *s2++;
71 if (c1 == '-')
72 c1 = '_';
73 if (c2 == '-')
74 c2 = '_';
75 if (c1 != c2)
76 return !match;
77 if (!c1)
78 break;
79 }
80#endif /* MODULE */
81 return match;
82}
83
84#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
85int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
86EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
87#endif
88
89static int check_empty_slot(struct module *module, int slot)
90{
91 return !slots[slot] || !*slots[slot];
92}
93
94/* return an empty slot number (>= 0) found in the given bitmask @mask.
95 * @mask == -1 == 0xffffffff means: take any free slot up to 32
96 * when no slot is available, return the original @mask as is.
97 */
98static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
99 struct module *module)
100{
101 int slot;
102
103 for (slot = 0; slot < SNDRV_CARDS; slot++) {
104 if (slot < 32 && !(mask & (1U << slot)))
105 continue;
106 if (!test_bit(slot, snd_cards_lock)) {
107 if (check(module, slot))
108 return slot; /* found */
109 }
110 }
111 return mask; /* unchanged */
112}
113
114/* the default release callback set in snd_device_alloc() */
115static void default_release_alloc(struct device *dev)
116{
117 kfree(objp: dev);
118}
119
120/**
121 * snd_device_alloc - Allocate and initialize struct device for sound devices
122 * @dev_p: pointer to store the allocated device
123 * @card: card to assign, optional
124 *
125 * For releasing the allocated device, call put_device().
126 */
127int snd_device_alloc(struct device **dev_p, struct snd_card *card)
128{
129 struct device *dev;
130
131 *dev_p = NULL;
132 dev = kzalloc(size: sizeof(*dev), GFP_KERNEL);
133 if (!dev)
134 return -ENOMEM;
135 device_initialize(dev);
136 if (card)
137 dev->parent = &card->card_dev;
138 dev->class = &sound_class;
139 dev->release = default_release_alloc;
140 *dev_p = dev;
141 return 0;
142}
143EXPORT_SYMBOL_GPL(snd_device_alloc);
144
145static int snd_card_init(struct snd_card *card, struct device *parent,
146 int idx, const char *xid, struct module *module,
147 size_t extra_size);
148static int snd_card_do_free(struct snd_card *card);
149static const struct attribute_group card_dev_attr_group;
150
151static void release_card_device(struct device *dev)
152{
153 snd_card_do_free(dev_to_snd_card(dev));
154}
155
156/**
157 * snd_card_new - create and initialize a soundcard structure
158 * @parent: the parent device object
159 * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
160 * @xid: card identification (ASCII string)
161 * @module: top level module for locking
162 * @extra_size: allocate this extra size after the main soundcard structure
163 * @card_ret: the pointer to store the created card instance
164 *
165 * The function allocates snd_card instance via kzalloc with the given
166 * space for the driver to use freely. The allocated struct is stored
167 * in the given card_ret pointer.
168 *
169 * Return: Zero if successful or a negative error code.
170 */
171int snd_card_new(struct device *parent, int idx, const char *xid,
172 struct module *module, int extra_size,
173 struct snd_card **card_ret)
174{
175 struct snd_card *card;
176 int err;
177
178 if (snd_BUG_ON(!card_ret))
179 return -EINVAL;
180 *card_ret = NULL;
181
182 if (extra_size < 0)
183 extra_size = 0;
184 card = kzalloc(size: sizeof(*card) + extra_size, GFP_KERNEL);
185 if (!card)
186 return -ENOMEM;
187
188 err = snd_card_init(card, parent, idx, xid, module, extra_size);
189 if (err < 0)
190 return err; /* card is freed by error handler */
191
192 *card_ret = card;
193 return 0;
194}
195EXPORT_SYMBOL(snd_card_new);
196
197static void __snd_card_release(struct device *dev, void *data)
198{
199 snd_card_free(card: data);
200}
201
202/**
203 * snd_devm_card_new - managed snd_card object creation
204 * @parent: the parent device object
205 * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
206 * @xid: card identification (ASCII string)
207 * @module: top level module for locking
208 * @extra_size: allocate this extra size after the main soundcard structure
209 * @card_ret: the pointer to store the created card instance
210 *
211 * This function works like snd_card_new() but manages the allocated resource
212 * via devres, i.e. you don't need to free explicitly.
213 *
214 * When a snd_card object is created with this function and registered via
215 * snd_card_register(), the very first devres action to call snd_card_free()
216 * is added automatically. In that way, the resource disconnection is assured
217 * at first, then released in the expected order.
218 *
219 * If an error happens at the probe before snd_card_register() is called and
220 * there have been other devres resources, you'd need to free the card manually
221 * via snd_card_free() call in the error; otherwise it may lead to UAF due to
222 * devres call orders. You can use snd_card_free_on_error() helper for
223 * handling it more easily.
224 *
225 * Return: zero if successful, or a negative error code
226 */
227int snd_devm_card_new(struct device *parent, int idx, const char *xid,
228 struct module *module, size_t extra_size,
229 struct snd_card **card_ret)
230{
231 struct snd_card *card;
232 int err;
233
234 *card_ret = NULL;
235 card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
236 GFP_KERNEL);
237 if (!card)
238 return -ENOMEM;
239 card->managed = true;
240 err = snd_card_init(card, parent, idx, xid, module, extra_size);
241 if (err < 0) {
242 devres_free(res: card); /* in managed mode, we need to free manually */
243 return err;
244 }
245
246 devres_add(dev: parent, res: card);
247 *card_ret = card;
248 return 0;
249}
250EXPORT_SYMBOL_GPL(snd_devm_card_new);
251
252/**
253 * snd_card_free_on_error - a small helper for handling devm probe errors
254 * @dev: the managed device object
255 * @ret: the return code from the probe callback
256 *
257 * This function handles the explicit snd_card_free() call at the error from
258 * the probe callback. It's just a small helper for simplifying the error
259 * handling with the managed devices.
260 *
261 * Return: zero if successful, or a negative error code
262 */
263int snd_card_free_on_error(struct device *dev, int ret)
264{
265 struct snd_card *card;
266
267 if (!ret)
268 return 0;
269 card = devres_find(dev, release: __snd_card_release, NULL, NULL);
270 if (card)
271 snd_card_free(card);
272 return ret;
273}
274EXPORT_SYMBOL_GPL(snd_card_free_on_error);
275
276static int snd_card_init(struct snd_card *card, struct device *parent,
277 int idx, const char *xid, struct module *module,
278 size_t extra_size)
279{
280 int err;
281
282 if (extra_size > 0)
283 card->private_data = (char *)card + sizeof(struct snd_card);
284 if (xid)
285 strscpy(card->id, xid, sizeof(card->id));
286 err = 0;
287 scoped_guard(mutex, &snd_card_mutex) {
288 if (idx < 0) /* first check the matching module-name slot */
289 idx = get_slot_from_bitmask(mask: idx, check: module_slot_match, module);
290 if (idx < 0) /* if not matched, assign an empty slot */
291 idx = get_slot_from_bitmask(mask: idx, check: check_empty_slot, module);
292 if (idx < 0)
293 err = -ENODEV;
294 else if (idx < snd_ecards_limit) {
295 if (test_bit(idx, snd_cards_lock))
296 err = -EBUSY; /* invalid */
297 } else if (idx >= SNDRV_CARDS)
298 err = -ENODEV;
299 if (!err) {
300 set_bit(nr: idx, addr: snd_cards_lock); /* lock it */
301 if (idx >= snd_ecards_limit)
302 snd_ecards_limit = idx + 1; /* increase the limit */
303 }
304 }
305 if (err < 0) {
306 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
307 idx, snd_ecards_limit - 1, err);
308 if (!card->managed)
309 kfree(objp: card); /* manually free here, as no destructor called */
310 return err;
311 }
312 card->dev = parent;
313 card->number = idx;
314#ifdef MODULE
315 WARN_ON(!module);
316 card->module = module;
317#endif
318 INIT_LIST_HEAD(list: &card->devices);
319 init_rwsem(&card->controls_rwsem);
320 rwlock_init(&card->ctl_files_rwlock);
321 INIT_LIST_HEAD(list: &card->controls);
322 INIT_LIST_HEAD(list: &card->ctl_files);
323#ifdef CONFIG_SND_CTL_FAST_LOOKUP
324 xa_init(xa: &card->ctl_numids);
325 xa_init(xa: &card->ctl_hash);
326#endif
327 spin_lock_init(&card->files_lock);
328 INIT_LIST_HEAD(list: &card->files_list);
329 mutex_init(&card->memory_mutex);
330#ifdef CONFIG_PM
331 init_waitqueue_head(&card->power_sleep);
332 init_waitqueue_head(&card->power_ref_sleep);
333 atomic_set(v: &card->power_ref, i: 0);
334#endif
335 init_waitqueue_head(&card->remove_sleep);
336 card->sync_irq = -1;
337
338 device_initialize(dev: &card->card_dev);
339 card->card_dev.parent = parent;
340 card->card_dev.class = &sound_class;
341 card->card_dev.release = release_card_device;
342 card->card_dev.groups = card->dev_groups;
343 card->dev_groups[0] = &card_dev_attr_group;
344 err = kobject_set_name(kobj: &card->card_dev.kobj, name: "card%d", idx);
345 if (err < 0)
346 goto __error;
347
348 snprintf(buf: card->irq_descr, size: sizeof(card->irq_descr), fmt: "%s:%s",
349 dev_driver_string(dev: card->dev), dev_name(dev: &card->card_dev));
350
351 /* the control interface cannot be accessed from the user space until */
352 /* snd_cards_bitmask and snd_cards are set with snd_card_register */
353 err = snd_ctl_create(card);
354 if (err < 0) {
355 dev_err(parent, "unable to register control minors\n");
356 goto __error;
357 }
358 err = snd_info_card_create(card);
359 if (err < 0) {
360 dev_err(parent, "unable to create card info\n");
361 goto __error_ctl;
362 }
363
364#ifdef CONFIG_SND_DEBUG
365 card->debugfs_root = debugfs_create_dir(name: dev_name(dev: &card->card_dev),
366 parent: sound_debugfs_root);
367#endif
368 return 0;
369
370 __error_ctl:
371 snd_device_free_all(card);
372 __error:
373 put_device(dev: &card->card_dev);
374 return err;
375}
376
377/**
378 * snd_card_ref - Get the card object from the index
379 * @idx: the card index
380 *
381 * Returns a card object corresponding to the given index or NULL if not found.
382 * Release the object via snd_card_unref().
383 *
384 * Return: a card object or NULL
385 */
386struct snd_card *snd_card_ref(int idx)
387{
388 struct snd_card *card;
389
390 guard(mutex)(T: &snd_card_mutex);
391 card = snd_cards[idx];
392 if (card)
393 get_device(dev: &card->card_dev);
394 return card;
395}
396EXPORT_SYMBOL_GPL(snd_card_ref);
397
398/* return non-zero if a card is already locked */
399int snd_card_locked(int card)
400{
401 guard(mutex)(T: &snd_card_mutex);
402 return test_bit(card, snd_cards_lock);
403}
404
405static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
406{
407 return -ENODEV;
408}
409
410static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
411 size_t count, loff_t *offset)
412{
413 return -ENODEV;
414}
415
416static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
417 size_t count, loff_t *offset)
418{
419 return -ENODEV;
420}
421
422static int snd_disconnect_release(struct inode *inode, struct file *file)
423{
424 struct snd_monitor_file *df = NULL, *_df;
425
426 scoped_guard(spinlock, &shutdown_lock) {
427 list_for_each_entry(_df, &shutdown_files, shutdown_list) {
428 if (_df->file == file) {
429 df = _df;
430 list_del_init(entry: &df->shutdown_list);
431 break;
432 }
433 }
434 }
435
436 if (likely(df)) {
437 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
438 df->disconnected_f_op->fasync(-1, file, 0);
439 return df->disconnected_f_op->release(inode, file);
440 }
441
442 panic(fmt: "%s(%p, %p) failed!", __func__, inode, file);
443}
444
445static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
446{
447 return EPOLLERR | EPOLLNVAL;
448}
449
450static long snd_disconnect_ioctl(struct file *file,
451 unsigned int cmd, unsigned long arg)
452{
453 return -ENODEV;
454}
455
456static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
457{
458 return -ENODEV;
459}
460
461static int snd_disconnect_fasync(int fd, struct file *file, int on)
462{
463 return -ENODEV;
464}
465
466static const struct file_operations snd_shutdown_f_ops =
467{
468 .owner = THIS_MODULE,
469 .llseek = snd_disconnect_llseek,
470 .read = snd_disconnect_read,
471 .write = snd_disconnect_write,
472 .release = snd_disconnect_release,
473 .poll = snd_disconnect_poll,
474 .unlocked_ioctl = snd_disconnect_ioctl,
475#ifdef CONFIG_COMPAT
476 .compat_ioctl = snd_disconnect_ioctl,
477#endif
478 .mmap = snd_disconnect_mmap,
479 .fasync = snd_disconnect_fasync
480};
481
482/**
483 * snd_card_disconnect - disconnect all APIs from the file-operations (user space)
484 * @card: soundcard structure
485 *
486 * Disconnects all APIs from the file-operations (user space).
487 *
488 * Return: Zero, otherwise a negative error code.
489 *
490 * Note: The current implementation replaces all active file->f_op with special
491 * dummy file operations (they do nothing except release).
492 */
493void snd_card_disconnect(struct snd_card *card)
494{
495 struct snd_monitor_file *mfile;
496
497 if (!card)
498 return;
499
500 scoped_guard(spinlock, &card->files_lock) {
501 if (card->shutdown)
502 return;
503 card->shutdown = 1;
504
505 /* replace file->f_op with special dummy operations */
506 list_for_each_entry(mfile, &card->files_list, list) {
507 /* it's critical part, use endless loop */
508 /* we have no room to fail */
509 mfile->disconnected_f_op = mfile->file->f_op;
510
511 scoped_guard(spinlock, &shutdown_lock)
512 list_add(new: &mfile->shutdown_list, head: &shutdown_files);
513
514 mfile->file->f_op = &snd_shutdown_f_ops;
515 fops_get(mfile->file->f_op);
516 }
517 }
518
519 /* notify all connected devices about disconnection */
520 /* at this point, they cannot respond to any calls except release() */
521
522#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
523 if (snd_mixer_oss_notify_callback)
524 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
525#endif
526
527 /* notify all devices that we are disconnected */
528 snd_device_disconnect_all(card);
529
530 if (card->sync_irq > 0)
531 synchronize_irq(irq: card->sync_irq);
532
533 snd_info_card_disconnect(card);
534 if (card->registered) {
535 device_del(dev: &card->card_dev);
536 card->registered = false;
537 }
538
539 /* disable fops (user space) operations for ALSA API */
540 scoped_guard(mutex, &snd_card_mutex) {
541 snd_cards[card->number] = NULL;
542 clear_bit(nr: card->number, addr: snd_cards_lock);
543 }
544
545#ifdef CONFIG_PM
546 wake_up(&card->power_sleep);
547 snd_power_sync_ref(card);
548#endif
549}
550EXPORT_SYMBOL(snd_card_disconnect);
551
552/**
553 * snd_card_disconnect_sync - disconnect card and wait until files get closed
554 * @card: card object to disconnect
555 *
556 * This calls snd_card_disconnect() for disconnecting all belonging components
557 * and waits until all pending files get closed.
558 * It assures that all accesses from user-space finished so that the driver
559 * can release its resources gracefully.
560 */
561void snd_card_disconnect_sync(struct snd_card *card)
562{
563 snd_card_disconnect(card);
564
565 guard(spinlock_irq)(l: &card->files_lock);
566 wait_event_lock_irq(card->remove_sleep,
567 list_empty(&card->files_list),
568 card->files_lock);
569}
570EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
571
572static int snd_card_do_free(struct snd_card *card)
573{
574 card->releasing = true;
575#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
576 if (snd_mixer_oss_notify_callback)
577 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
578#endif
579 snd_device_free_all(card);
580 if (card->private_free)
581 card->private_free(card);
582 if (snd_info_card_free(card) < 0) {
583 dev_warn(card->dev, "unable to free card info\n");
584 /* Not fatal error */
585 }
586#ifdef CONFIG_SND_DEBUG
587 debugfs_remove(dentry: card->debugfs_root);
588 card->debugfs_root = NULL;
589#endif
590 if (card->release_completion)
591 complete(card->release_completion);
592 if (!card->managed)
593 kfree(objp: card);
594 return 0;
595}
596
597/**
598 * snd_card_free_when_closed - Disconnect the card, free it later eventually
599 * @card: soundcard structure
600 *
601 * Unlike snd_card_free(), this function doesn't try to release the card
602 * resource immediately, but tries to disconnect at first. When the card
603 * is still in use, the function returns before freeing the resources.
604 * The card resources will be freed when the refcount gets to zero.
605 *
606 * Return: zero if successful, or a negative error code
607 */
608void snd_card_free_when_closed(struct snd_card *card)
609{
610 if (!card)
611 return;
612
613 snd_card_disconnect(card);
614 put_device(dev: &card->card_dev);
615 return;
616}
617EXPORT_SYMBOL(snd_card_free_when_closed);
618
619/**
620 * snd_card_free - frees given soundcard structure
621 * @card: soundcard structure
622 *
623 * This function releases the soundcard structure and the all assigned
624 * devices automatically. That is, you don't have to release the devices
625 * by yourself.
626 *
627 * This function waits until the all resources are properly released.
628 *
629 * Return: Zero. Frees all associated devices and frees the control
630 * interface associated to given soundcard.
631 */
632void snd_card_free(struct snd_card *card)
633{
634 DECLARE_COMPLETION_ONSTACK(released);
635
636 /* The call of snd_card_free() is allowed from various code paths;
637 * a manual call from the driver and the call via devres_free, and
638 * we need to avoid double-free. Moreover, the release via devres
639 * may call snd_card_free() twice due to its nature, we need to have
640 * the check here at the beginning.
641 */
642 if (card->releasing)
643 return;
644
645 card->release_completion = &released;
646 snd_card_free_when_closed(card);
647
648 /* wait, until all devices are ready for the free operation */
649 wait_for_completion(&released);
650}
651EXPORT_SYMBOL(snd_card_free);
652
653/* retrieve the last word of shortname or longname */
654static const char *retrieve_id_from_card_name(const char *name)
655{
656 const char *spos = name;
657
658 while (*name) {
659 if (isspace(*name) && isalnum(name[1]))
660 spos = name + 1;
661 name++;
662 }
663 return spos;
664}
665
666/* return true if the given id string doesn't conflict any other card ids */
667static bool card_id_ok(struct snd_card *card, const char *id)
668{
669 int i;
670 if (!snd_info_check_reserved_words(str: id))
671 return false;
672 for (i = 0; i < snd_ecards_limit; i++) {
673 if (snd_cards[i] && snd_cards[i] != card &&
674 !strcmp(snd_cards[i]->id, id))
675 return false;
676 }
677 return true;
678}
679
680/* copy to card->id only with valid letters from nid */
681static void copy_valid_id_string(struct snd_card *card, const char *src,
682 const char *nid)
683{
684 char *id = card->id;
685
686 while (*nid && !isalnum(*nid))
687 nid++;
688 if (isdigit(c: *nid))
689 *id++ = isalpha(*src) ? *src : 'D';
690 while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
691 if (isalnum(*nid))
692 *id++ = *nid;
693 nid++;
694 }
695 *id = 0;
696}
697
698/* Set card->id from the given string
699 * If the string conflicts with other ids, add a suffix to make it unique.
700 */
701static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
702 const char *nid)
703{
704 int len, loops;
705 bool is_default = false;
706 char *id;
707
708 copy_valid_id_string(card, src, nid);
709 id = card->id;
710
711 again:
712 /* use "Default" for obviously invalid strings
713 * ("card" conflicts with proc directories)
714 */
715 if (!*id || !strncmp(id, "card", 4)) {
716 strcpy(p: id, q: "Default");
717 is_default = true;
718 }
719
720 len = strlen(id);
721 for (loops = 0; loops < SNDRV_CARDS; loops++) {
722 char *spos;
723 char sfxstr[5]; /* "_012" */
724 int sfxlen;
725
726 if (card_id_ok(card, id))
727 return; /* OK */
728
729 /* Add _XYZ suffix */
730 sprintf(buf: sfxstr, fmt: "_%X", loops + 1);
731 sfxlen = strlen(sfxstr);
732 if (len + sfxlen >= sizeof(card->id))
733 spos = id + sizeof(card->id) - sfxlen - 1;
734 else
735 spos = id + len;
736 strcpy(p: spos, q: sfxstr);
737 }
738 /* fallback to the default id */
739 if (!is_default) {
740 *id = 0;
741 goto again;
742 }
743 /* last resort... */
744 dev_err(card->dev, "unable to set card id (%s)\n", id);
745 if (card->proc_root->name)
746 strscpy(card->id, card->proc_root->name, sizeof(card->id));
747}
748
749/**
750 * snd_card_set_id - set card identification name
751 * @card: soundcard structure
752 * @nid: new identification string
753 *
754 * This function sets the card identification and checks for name
755 * collisions.
756 */
757void snd_card_set_id(struct snd_card *card, const char *nid)
758{
759 /* check if user specified own card->id */
760 if (card->id[0] != '\0')
761 return;
762 guard(mutex)(T: &snd_card_mutex);
763 snd_card_set_id_no_lock(card, src: nid, nid);
764}
765EXPORT_SYMBOL(snd_card_set_id);
766
767static ssize_t id_show(struct device *dev,
768 struct device_attribute *attr, char *buf)
769{
770 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
771 return sysfs_emit(buf, fmt: "%s\n", card->id);
772}
773
774static ssize_t id_store(struct device *dev, struct device_attribute *attr,
775 const char *buf, size_t count)
776{
777 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
778 char buf1[sizeof(card->id)];
779 size_t copy = count > sizeof(card->id) - 1 ?
780 sizeof(card->id) - 1 : count;
781 size_t idx;
782 int c;
783
784 for (idx = 0; idx < copy; idx++) {
785 c = buf[idx];
786 if (!isalnum(c) && c != '_' && c != '-')
787 return -EINVAL;
788 }
789 memcpy(buf1, buf, copy);
790 buf1[copy] = '\0';
791 guard(mutex)(T: &snd_card_mutex);
792 if (!card_id_ok(NULL, id: buf1))
793 return -EEXIST;
794 strcpy(p: card->id, q: buf1);
795 snd_info_card_id_change(card);
796
797 return count;
798}
799
800static DEVICE_ATTR_RW(id);
801
802static ssize_t number_show(struct device *dev,
803 struct device_attribute *attr, char *buf)
804{
805 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
806 return sysfs_emit(buf, fmt: "%i\n", card->number);
807}
808
809static DEVICE_ATTR_RO(number);
810
811static struct attribute *card_dev_attrs[] = {
812 &dev_attr_id.attr,
813 &dev_attr_number.attr,
814 NULL
815};
816
817static const struct attribute_group card_dev_attr_group = {
818 .attrs = card_dev_attrs,
819};
820
821/**
822 * snd_card_add_dev_attr - Append a new sysfs attribute group to card
823 * @card: card instance
824 * @group: attribute group to append
825 *
826 * Return: zero if successful, or a negative error code
827 */
828int snd_card_add_dev_attr(struct snd_card *card,
829 const struct attribute_group *group)
830{
831 int i;
832
833 /* loop for (arraysize-1) here to keep NULL at the last entry */
834 for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
835 if (!card->dev_groups[i]) {
836 card->dev_groups[i] = group;
837 return 0;
838 }
839 }
840
841 dev_err(card->dev, "Too many groups assigned\n");
842 return -ENOSPC;
843}
844EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
845
846static void trigger_card_free(void *data)
847{
848 snd_card_free(data);
849}
850
851/**
852 * snd_card_register - register the soundcard
853 * @card: soundcard structure
854 *
855 * This function registers all the devices assigned to the soundcard.
856 * Until calling this, the ALSA control interface is blocked from the
857 * external accesses. Thus, you should call this function at the end
858 * of the initialization of the card.
859 *
860 * Return: Zero otherwise a negative error code if the registration failed.
861 */
862int snd_card_register(struct snd_card *card)
863{
864 int err;
865
866 if (snd_BUG_ON(!card))
867 return -EINVAL;
868
869 if (!card->registered) {
870 err = device_add(dev: &card->card_dev);
871 if (err < 0)
872 return err;
873 card->registered = true;
874 } else {
875 if (card->managed)
876 devm_remove_action(dev: card->dev, action: trigger_card_free, data: card);
877 }
878
879 if (card->managed) {
880 err = devm_add_action(card->dev, trigger_card_free, card);
881 if (err < 0)
882 return err;
883 }
884
885 err = snd_device_register_all(card);
886 if (err < 0)
887 return err;
888 scoped_guard(mutex, &snd_card_mutex) {
889 if (snd_cards[card->number]) {
890 /* already registered */
891 return snd_info_card_register(card); /* register pending info */
892 }
893 if (*card->id) {
894 /* make a unique id name from the given string */
895 char tmpid[sizeof(card->id)];
896
897 memcpy(tmpid, card->id, sizeof(card->id));
898 snd_card_set_id_no_lock(card, src: tmpid, nid: tmpid);
899 } else {
900 /* create an id from either shortname or longname */
901 const char *src;
902
903 src = *card->shortname ? card->shortname : card->longname;
904 snd_card_set_id_no_lock(card, src,
905 nid: retrieve_id_from_card_name(name: src));
906 }
907 snd_cards[card->number] = card;
908 }
909 err = snd_info_card_register(card);
910 if (err < 0)
911 return err;
912
913#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
914 if (snd_mixer_oss_notify_callback)
915 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
916#endif
917 return 0;
918}
919EXPORT_SYMBOL(snd_card_register);
920
921#ifdef CONFIG_SND_PROC_FS
922static void snd_card_info_read(struct snd_info_entry *entry,
923 struct snd_info_buffer *buffer)
924{
925 int idx, count;
926 struct snd_card *card;
927
928 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
929 guard(mutex)(T: &snd_card_mutex);
930 card = snd_cards[idx];
931 if (card) {
932 count++;
933 snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
934 idx,
935 card->id,
936 card->driver,
937 card->shortname);
938 snd_iprintf(buffer, " %s\n",
939 card->longname);
940 }
941 }
942 if (!count)
943 snd_iprintf(buffer, "--- no soundcards ---\n");
944}
945
946#ifdef CONFIG_SND_OSSEMUL
947void snd_card_info_read_oss(struct snd_info_buffer *buffer)
948{
949 int idx, count;
950 struct snd_card *card;
951
952 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
953 guard(mutex)(T: &snd_card_mutex);
954 card = snd_cards[idx];
955 if (card) {
956 count++;
957 snd_iprintf(buffer, "%s\n", card->longname);
958 }
959 }
960 if (!count) {
961 snd_iprintf(buffer, "--- no soundcards ---\n");
962 }
963}
964
965#endif
966
967#ifdef MODULE
968static void snd_card_module_info_read(struct snd_info_entry *entry,
969 struct snd_info_buffer *buffer)
970{
971 int idx;
972 struct snd_card *card;
973
974 for (idx = 0; idx < SNDRV_CARDS; idx++) {
975 guard(mutex)(&snd_card_mutex);
976 card = snd_cards[idx];
977 if (card)
978 snd_iprintf(buffer, "%2i %s\n",
979 idx, card->module->name);
980 }
981}
982#endif
983
984int __init snd_card_info_init(void)
985{
986 struct snd_info_entry *entry;
987
988 entry = snd_info_create_module_entry(THIS_MODULE, name: "cards", NULL);
989 if (! entry)
990 return -ENOMEM;
991 entry->c.text.read = snd_card_info_read;
992 if (snd_info_register(entry) < 0)
993 return -ENOMEM; /* freed in error path */
994
995#ifdef MODULE
996 entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
997 if (!entry)
998 return -ENOMEM;
999 entry->c.text.read = snd_card_module_info_read;
1000 if (snd_info_register(entry) < 0)
1001 return -ENOMEM; /* freed in error path */
1002#endif
1003
1004 return 0;
1005}
1006#endif /* CONFIG_SND_PROC_FS */
1007
1008/**
1009 * snd_component_add - add a component string
1010 * @card: soundcard structure
1011 * @component: the component id string
1012 *
1013 * This function adds the component id string to the supported list.
1014 * The component can be referred from the alsa-lib.
1015 *
1016 * Return: Zero otherwise a negative error code.
1017 */
1018
1019int snd_component_add(struct snd_card *card, const char *component)
1020{
1021 char *ptr;
1022 int len = strlen(component);
1023
1024 ptr = strstr(card->components, component);
1025 if (ptr != NULL) {
1026 if (ptr[len] == '\0' || ptr[len] == ' ') /* already there */
1027 return 1;
1028 }
1029 if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
1030 snd_BUG();
1031 return -ENOMEM;
1032 }
1033 if (card->components[0] != '\0')
1034 strcat(p: card->components, q: " ");
1035 strcat(p: card->components, q: component);
1036 return 0;
1037}
1038EXPORT_SYMBOL(snd_component_add);
1039
1040/**
1041 * snd_card_file_add - add the file to the file list of the card
1042 * @card: soundcard structure
1043 * @file: file pointer
1044 *
1045 * This function adds the file to the file linked-list of the card.
1046 * This linked-list is used to keep tracking the connection state,
1047 * and to avoid the release of busy resources by hotplug.
1048 *
1049 * Return: zero or a negative error code.
1050 */
1051int snd_card_file_add(struct snd_card *card, struct file *file)
1052{
1053 struct snd_monitor_file *mfile;
1054
1055 mfile = kmalloc(size: sizeof(*mfile), GFP_KERNEL);
1056 if (mfile == NULL)
1057 return -ENOMEM;
1058 mfile->file = file;
1059 mfile->disconnected_f_op = NULL;
1060 INIT_LIST_HEAD(list: &mfile->shutdown_list);
1061 guard(spinlock)(l: &card->files_lock);
1062 if (card->shutdown) {
1063 kfree(objp: mfile);
1064 return -ENODEV;
1065 }
1066 list_add(new: &mfile->list, head: &card->files_list);
1067 get_device(dev: &card->card_dev);
1068 return 0;
1069}
1070EXPORT_SYMBOL(snd_card_file_add);
1071
1072/**
1073 * snd_card_file_remove - remove the file from the file list
1074 * @card: soundcard structure
1075 * @file: file pointer
1076 *
1077 * This function removes the file formerly added to the card via
1078 * snd_card_file_add() function.
1079 * If all files are removed and snd_card_free_when_closed() was
1080 * called beforehand, it processes the pending release of
1081 * resources.
1082 *
1083 * Return: Zero or a negative error code.
1084 */
1085int snd_card_file_remove(struct snd_card *card, struct file *file)
1086{
1087 struct snd_monitor_file *mfile, *found = NULL;
1088
1089 scoped_guard(spinlock, &card->files_lock) {
1090 list_for_each_entry(mfile, &card->files_list, list) {
1091 if (mfile->file == file) {
1092 list_del(entry: &mfile->list);
1093 scoped_guard(spinlock, &shutdown_lock)
1094 list_del(entry: &mfile->shutdown_list);
1095 if (mfile->disconnected_f_op)
1096 fops_put(mfile->disconnected_f_op);
1097 found = mfile;
1098 break;
1099 }
1100 }
1101 if (list_empty(head: &card->files_list))
1102 wake_up_all(&card->remove_sleep);
1103 }
1104 if (!found) {
1105 dev_err(card->dev, "card file remove problem (%p)\n", file);
1106 return -ENOENT;
1107 }
1108 kfree(objp: found);
1109 put_device(dev: &card->card_dev);
1110 return 0;
1111}
1112EXPORT_SYMBOL(snd_card_file_remove);
1113
1114#ifdef CONFIG_PM
1115/**
1116 * snd_power_ref_and_wait - wait until the card gets powered up
1117 * @card: soundcard structure
1118 *
1119 * Take the power_ref reference count of the given card, and
1120 * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1121 * The refcount is down again while sleeping until power-up, hence this
1122 * function can be used for syncing the floating control ops accesses,
1123 * typically around calling control ops.
1124 *
1125 * The caller needs to pull down the refcount via snd_power_unref() later
1126 * no matter whether the error is returned from this function or not.
1127 *
1128 * Return: Zero if successful, or a negative error code.
1129 */
1130int snd_power_ref_and_wait(struct snd_card *card)
1131{
1132 snd_power_ref(card);
1133 if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1134 return 0;
1135 wait_event_cmd(card->power_sleep,
1136 card->shutdown ||
1137 snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
1138 snd_power_unref(card), snd_power_ref(card));
1139 return card->shutdown ? -ENODEV : 0;
1140}
1141EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
1142
1143/**
1144 * snd_power_wait - wait until the card gets powered up (old form)
1145 * @card: soundcard structure
1146 *
1147 * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1148 *
1149 * Return: Zero if successful, or a negative error code.
1150 */
1151int snd_power_wait(struct snd_card *card)
1152{
1153 int ret;
1154
1155 ret = snd_power_ref_and_wait(card);
1156 snd_power_unref(card);
1157 return ret;
1158}
1159EXPORT_SYMBOL(snd_power_wait);
1160#endif /* CONFIG_PM */
1161

source code of linux/sound/core/init.c