1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Initialization routines
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>
16 #include <linux/debugfs.h>
17 #include <linux/completion.h>
18 #include <linux/interrupt.h>
20 #include <sound/core.h>
21 #include <sound/control.h>
22 #include <sound/info.h>
24 /* monitor files for graceful shutdown (hotplug) */
25 struct snd_monitor_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 */
32 static DEFINE_SPINLOCK(shutdown_lock);
33 static LIST_HEAD(shutdown_files);
35 static const struct file_operations snd_shutdown_f_ops;
37 /* locked for registering/using */
38 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
39 static struct snd_card *snd_cards[SNDRV_CARDS];
41 static DEFINE_MUTEX(snd_card_mutex);
43 static char *slots[SNDRV_CARDS];
44 module_param_array(slots, charp, NULL, 0444);
45 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
47 /* return non-zero if the given index is reserved for the given
48 * module via slots option
50 static int module_slot_match(struct module *module, int idx)
56 if (!module || !*module->name || !slots[idx])
62 match = 0; /* negative match */
65 /* compare module name strings
66 * hyphens are handled as equivalent with underscore
80 #endif /* CONFIG_MODULES */
84 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
85 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
86 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
89 static int check_empty_slot(struct module *module, int slot)
91 return !slots[slot] || !*slots[slot];
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.
98 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
99 struct module *module)
103 for (slot = 0; slot < SNDRV_CARDS; slot++) {
104 if (slot < 32 && !(mask & (1U << slot)))
106 if (!test_bit(slot, snd_cards_lock)) {
107 if (check(module, slot))
108 return slot; /* found */
111 return mask; /* unchanged */
114 /* the default release callback set in snd_device_alloc() */
115 static void default_release_alloc(struct device *dev)
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
125 * For releasing the allocated device, call put_device().
127 int snd_device_alloc(struct device **dev_p, struct snd_card *card)
132 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
135 device_initialize(dev);
137 dev->parent = &card->card_dev;
138 dev->class = &sound_class;
139 dev->release = default_release_alloc;
143 EXPORT_SYMBOL_GPL(snd_device_alloc);
145 static int snd_card_init(struct snd_card *card, struct device *parent,
146 int idx, const char *xid, struct module *module,
148 static int snd_card_do_free(struct snd_card *card);
149 static const struct attribute_group card_dev_attr_group;
151 static void release_card_device(struct device *dev)
153 snd_card_do_free(dev_to_snd_card(dev));
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
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.
169 * Return: Zero if successful or a negative error code.
171 int snd_card_new(struct device *parent, int idx, const char *xid,
172 struct module *module, int extra_size,
173 struct snd_card **card_ret)
175 struct snd_card *card;
178 if (snd_BUG_ON(!card_ret))
184 card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
188 err = snd_card_init(card, parent, idx, xid, module, extra_size);
190 return err; /* card is freed by error handler */
195 EXPORT_SYMBOL(snd_card_new);
197 static void __snd_card_release(struct device *dev, void *data)
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
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.
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.
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.
225 * Return: zero if successful, or a negative error code
227 int 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)
231 struct snd_card *card;
235 card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
239 card->managed = true;
240 err = snd_card_init(card, parent, idx, xid, module, extra_size);
242 devres_free(card); /* in managed mode, we need to free manually */
246 devres_add(parent, card);
250 EXPORT_SYMBOL_GPL(snd_devm_card_new);
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
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.
261 * Return: zero if successful, or a negative error code
263 int snd_card_free_on_error(struct device *dev, int ret)
265 struct snd_card *card;
269 card = devres_find(dev, __snd_card_release, NULL, NULL);
274 EXPORT_SYMBOL_GPL(snd_card_free_on_error);
276 static int snd_card_init(struct snd_card *card, struct device *parent,
277 int idx, const char *xid, struct module *module,
283 card->private_data = (char *)card + sizeof(struct snd_card);
285 strscpy(card->id, xid, sizeof(card->id));
287 scoped_guard(mutex, &snd_card_mutex) {
288 if (idx < 0) /* first check the matching module-name slot */
289 idx = get_slot_from_bitmask(idx, module_slot_match, module);
290 if (idx < 0) /* if not matched, assign an empty slot */
291 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
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)
300 set_bit(idx, snd_cards_lock); /* lock it */
301 if (idx >= snd_ecards_limit)
302 snd_ecards_limit = idx + 1; /* increase the limit */
306 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
307 idx, snd_ecards_limit - 1, err);
309 kfree(card); /* manually free here, as no destructor called */
314 WARN_ON(IS_MODULE(CONFIG_SND) && !module);
315 card->module = module;
316 INIT_LIST_HEAD(&card->devices);
317 init_rwsem(&card->controls_rwsem);
318 rwlock_init(&card->ctl_files_rwlock);
319 INIT_LIST_HEAD(&card->controls);
320 INIT_LIST_HEAD(&card->ctl_files);
321 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
322 xa_init(&card->ctl_numids);
323 xa_init(&card->ctl_hash);
325 spin_lock_init(&card->files_lock);
326 INIT_LIST_HEAD(&card->files_list);
327 mutex_init(&card->memory_mutex);
329 init_waitqueue_head(&card->power_sleep);
330 init_waitqueue_head(&card->power_ref_sleep);
331 atomic_set(&card->power_ref, 0);
333 init_waitqueue_head(&card->remove_sleep);
336 device_initialize(&card->card_dev);
337 card->card_dev.parent = parent;
338 card->card_dev.class = &sound_class;
339 card->card_dev.release = release_card_device;
340 card->card_dev.groups = card->dev_groups;
341 card->dev_groups[0] = &card_dev_attr_group;
342 err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
346 snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
347 dev_driver_string(card->dev), dev_name(&card->card_dev));
349 /* the control interface cannot be accessed from the user space until */
350 /* snd_cards_bitmask and snd_cards are set with snd_card_register */
351 err = snd_ctl_create(card);
353 dev_err(parent, "unable to register control minors\n");
356 err = snd_info_card_create(card);
358 dev_err(parent, "unable to create card info\n");
362 #ifdef CONFIG_SND_DEBUG
363 card->debugfs_root = debugfs_create_dir(dev_name(&card->card_dev),
369 snd_device_free_all(card);
371 put_device(&card->card_dev);
376 * snd_card_ref - Get the card object from the index
377 * @idx: the card index
379 * Returns a card object corresponding to the given index or NULL if not found.
380 * Release the object via snd_card_unref().
382 * Return: a card object or NULL
384 struct snd_card *snd_card_ref(int idx)
386 struct snd_card *card;
388 guard(mutex)(&snd_card_mutex);
389 card = snd_cards[idx];
391 get_device(&card->card_dev);
394 EXPORT_SYMBOL_GPL(snd_card_ref);
396 /* return non-zero if a card is already locked */
397 int snd_card_locked(int card)
399 guard(mutex)(&snd_card_mutex);
400 return test_bit(card, snd_cards_lock);
403 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
408 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
409 size_t count, loff_t *offset)
414 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
415 size_t count, loff_t *offset)
420 static int snd_disconnect_release(struct inode *inode, struct file *file)
422 struct snd_monitor_file *df = NULL, *_df;
424 scoped_guard(spinlock, &shutdown_lock) {
425 list_for_each_entry(_df, &shutdown_files, shutdown_list) {
426 if (_df->file == file) {
428 list_del_init(&df->shutdown_list);
435 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
436 df->disconnected_f_op->fasync(-1, file, 0);
437 return df->disconnected_f_op->release(inode, file);
440 panic("%s(%p, %p) failed!", __func__, inode, file);
443 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
445 return EPOLLERR | EPOLLNVAL;
448 static long snd_disconnect_ioctl(struct file *file,
449 unsigned int cmd, unsigned long arg)
454 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
459 static int snd_disconnect_fasync(int fd, struct file *file, int on)
464 static const struct file_operations snd_shutdown_f_ops =
466 .owner = THIS_MODULE,
467 .llseek = snd_disconnect_llseek,
468 .read = snd_disconnect_read,
469 .write = snd_disconnect_write,
470 .release = snd_disconnect_release,
471 .poll = snd_disconnect_poll,
472 .unlocked_ioctl = snd_disconnect_ioctl,
474 .compat_ioctl = snd_disconnect_ioctl,
476 .mmap = snd_disconnect_mmap,
477 .fasync = snd_disconnect_fasync
481 * snd_card_disconnect - disconnect all APIs from the file-operations (user space)
482 * @card: soundcard structure
484 * Disconnects all APIs from the file-operations (user space).
486 * Return: Zero, otherwise a negative error code.
488 * Note: The current implementation replaces all active file->f_op with special
489 * dummy file operations (they do nothing except release).
491 void snd_card_disconnect(struct snd_card *card)
493 struct snd_monitor_file *mfile;
498 scoped_guard(spinlock, &card->files_lock) {
503 /* replace file->f_op with special dummy operations */
504 list_for_each_entry(mfile, &card->files_list, list) {
505 /* it's critical part, use endless loop */
506 /* we have no room to fail */
507 mfile->disconnected_f_op = mfile->file->f_op;
509 scoped_guard(spinlock, &shutdown_lock)
510 list_add(&mfile->shutdown_list, &shutdown_files);
512 mfile->file->f_op = &snd_shutdown_f_ops;
513 fops_get(mfile->file->f_op);
518 /* wake up sleepers here before other callbacks for avoiding potential
519 * deadlocks with other locks (e.g. in kctls);
520 * then this notifies the shutdown and sleepers would abort immediately
522 wake_up_all(&card->power_sleep);
525 /* notify all connected devices about disconnection */
526 /* at this point, they cannot respond to any calls except release() */
528 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
529 if (snd_mixer_oss_notify_callback)
530 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
533 /* notify all devices that we are disconnected */
534 snd_device_disconnect_all(card);
536 if (card->sync_irq > 0)
537 synchronize_irq(card->sync_irq);
539 snd_info_card_disconnect(card);
540 if (card->registered) {
541 device_del(&card->card_dev);
542 card->registered = false;
545 /* disable fops (user space) operations for ALSA API */
546 scoped_guard(mutex, &snd_card_mutex) {
547 snd_cards[card->number] = NULL;
548 clear_bit(card->number, snd_cards_lock);
551 snd_power_sync_ref(card);
553 EXPORT_SYMBOL(snd_card_disconnect);
556 * snd_card_disconnect_sync - disconnect card and wait until files get closed
557 * @card: card object to disconnect
559 * This calls snd_card_disconnect() for disconnecting all belonging components
560 * and waits until all pending files get closed.
561 * It assures that all accesses from user-space finished so that the driver
562 * can release its resources gracefully.
564 void snd_card_disconnect_sync(struct snd_card *card)
566 snd_card_disconnect(card);
568 guard(spinlock_irq)(&card->files_lock);
569 wait_event_lock_irq(card->remove_sleep,
570 list_empty(&card->files_list),
573 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
575 static int snd_card_do_free(struct snd_card *card)
577 card->releasing = true;
578 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
579 if (snd_mixer_oss_notify_callback)
580 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
582 snd_device_free_all(card);
583 if (card->private_free)
584 card->private_free(card);
585 if (snd_info_card_free(card) < 0) {
586 dev_warn(card->dev, "unable to free card info\n");
587 /* Not fatal error */
589 #ifdef CONFIG_SND_DEBUG
590 debugfs_remove(card->debugfs_root);
591 card->debugfs_root = NULL;
593 if (card->release_completion)
594 complete(card->release_completion);
601 * snd_card_free_when_closed - Disconnect the card, free it later eventually
602 * @card: soundcard structure
604 * Unlike snd_card_free(), this function doesn't try to release the card
605 * resource immediately, but tries to disconnect at first. When the card
606 * is still in use, the function returns before freeing the resources.
607 * The card resources will be freed when the refcount gets to zero.
609 * Return: zero if successful, or a negative error code
611 void snd_card_free_when_closed(struct snd_card *card)
616 snd_card_disconnect(card);
617 put_device(&card->card_dev);
620 EXPORT_SYMBOL(snd_card_free_when_closed);
623 * snd_card_free - frees given soundcard structure
624 * @card: soundcard structure
626 * This function releases the soundcard structure and the all assigned
627 * devices automatically. That is, you don't have to release the devices
630 * This function waits until the all resources are properly released.
632 * Return: Zero. Frees all associated devices and frees the control
633 * interface associated to given soundcard.
635 void snd_card_free(struct snd_card *card)
637 DECLARE_COMPLETION_ONSTACK(released);
639 /* The call of snd_card_free() is allowed from various code paths;
640 * a manual call from the driver and the call via devres_free, and
641 * we need to avoid double-free. Moreover, the release via devres
642 * may call snd_card_free() twice due to its nature, we need to have
643 * the check here at the beginning.
648 card->release_completion = &released;
649 snd_card_free_when_closed(card);
651 /* wait, until all devices are ready for the free operation */
652 wait_for_completion(&released);
654 EXPORT_SYMBOL(snd_card_free);
656 /* retrieve the last word of shortname or longname */
657 static const char *retrieve_id_from_card_name(const char *name)
659 const char *spos = name;
662 if (isspace(*name) && isalnum(name[1]))
669 /* return true if the given id string doesn't conflict any other card ids */
670 static bool card_id_ok(struct snd_card *card, const char *id)
673 if (!snd_info_check_reserved_words(id))
675 for (i = 0; i < snd_ecards_limit; i++) {
676 if (snd_cards[i] && snd_cards[i] != card &&
677 !strcmp(snd_cards[i]->id, id))
683 /* copy to card->id only with valid letters from nid */
684 static void copy_valid_id_string(struct snd_card *card, const char *src,
689 while (*nid && !isalnum(*nid))
692 *id++ = isalpha(*src) ? *src : 'D';
693 while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
701 /* Set card->id from the given string
702 * If the string conflicts with other ids, add a suffix to make it unique.
704 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
708 bool is_default = false;
711 copy_valid_id_string(card, src, nid);
715 /* use "Default" for obviously invalid strings
716 * ("card" conflicts with proc directories)
718 if (!*id || !strncmp(id, "card", 4)) {
719 strcpy(id, "Default");
724 for (loops = 0; loops < SNDRV_CARDS; loops++) {
726 char sfxstr[5]; /* "_012" */
729 if (card_id_ok(card, id))
732 /* Add _XYZ suffix */
733 sprintf(sfxstr, "_%X", loops + 1);
734 sfxlen = strlen(sfxstr);
735 if (len + sfxlen >= sizeof(card->id))
736 spos = id + sizeof(card->id) - sfxlen - 1;
739 strcpy(spos, sfxstr);
741 /* fallback to the default id */
747 dev_err(card->dev, "unable to set card id (%s)\n", id);
748 if (card->proc_root->name)
749 strscpy(card->id, card->proc_root->name, sizeof(card->id));
753 * snd_card_set_id - set card identification name
754 * @card: soundcard structure
755 * @nid: new identification string
757 * This function sets the card identification and checks for name
760 void snd_card_set_id(struct snd_card *card, const char *nid)
762 /* check if user specified own card->id */
763 if (card->id[0] != '\0')
765 guard(mutex)(&snd_card_mutex);
766 snd_card_set_id_no_lock(card, nid, nid);
768 EXPORT_SYMBOL(snd_card_set_id);
770 static ssize_t id_show(struct device *dev,
771 struct device_attribute *attr, char *buf)
773 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
774 return sysfs_emit(buf, "%s\n", card->id);
777 static ssize_t id_store(struct device *dev, struct device_attribute *attr,
778 const char *buf, size_t count)
780 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
781 char buf1[sizeof(card->id)];
782 size_t copy = count > sizeof(card->id) - 1 ?
783 sizeof(card->id) - 1 : count;
787 for (idx = 0; idx < copy; idx++) {
789 if (!isalnum(c) && c != '_' && c != '-')
792 memcpy(buf1, buf, copy);
794 guard(mutex)(&snd_card_mutex);
795 if (!card_id_ok(NULL, buf1))
797 strcpy(card->id, buf1);
798 snd_info_card_id_change(card);
803 static DEVICE_ATTR_RW(id);
805 static ssize_t number_show(struct device *dev,
806 struct device_attribute *attr, char *buf)
808 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
809 return sysfs_emit(buf, "%i\n", card->number);
812 static DEVICE_ATTR_RO(number);
814 static struct attribute *card_dev_attrs[] = {
816 &dev_attr_number.attr,
820 static const struct attribute_group card_dev_attr_group = {
821 .attrs = card_dev_attrs,
825 * snd_card_add_dev_attr - Append a new sysfs attribute group to card
826 * @card: card instance
827 * @group: attribute group to append
829 * Return: zero if successful, or a negative error code
831 int snd_card_add_dev_attr(struct snd_card *card,
832 const struct attribute_group *group)
836 /* loop for (arraysize-1) here to keep NULL at the last entry */
837 for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
838 if (!card->dev_groups[i]) {
839 card->dev_groups[i] = group;
844 dev_err(card->dev, "Too many groups assigned\n");
847 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
849 static void trigger_card_free(void *data)
855 * snd_card_register - register the soundcard
856 * @card: soundcard structure
858 * This function registers all the devices assigned to the soundcard.
859 * Until calling this, the ALSA control interface is blocked from the
860 * external accesses. Thus, you should call this function at the end
861 * of the initialization of the card.
863 * Return: Zero otherwise a negative error code if the registration failed.
865 int snd_card_register(struct snd_card *card)
869 if (snd_BUG_ON(!card))
872 if (!card->registered) {
873 err = device_add(&card->card_dev);
876 card->registered = true;
879 devm_remove_action(card->dev, trigger_card_free, card);
883 err = devm_add_action(card->dev, trigger_card_free, card);
888 err = snd_device_register_all(card);
891 scoped_guard(mutex, &snd_card_mutex) {
892 if (snd_cards[card->number]) {
893 /* already registered */
894 return snd_info_card_register(card); /* register pending info */
897 /* make a unique id name from the given string */
898 char tmpid[sizeof(card->id)];
900 memcpy(tmpid, card->id, sizeof(card->id));
901 snd_card_set_id_no_lock(card, tmpid, tmpid);
903 /* create an id from either shortname or longname */
906 src = *card->shortname ? card->shortname : card->longname;
907 snd_card_set_id_no_lock(card, src,
908 retrieve_id_from_card_name(src));
910 snd_cards[card->number] = card;
912 err = snd_info_card_register(card);
916 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
917 if (snd_mixer_oss_notify_callback)
918 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
922 EXPORT_SYMBOL(snd_card_register);
924 #ifdef CONFIG_SND_PROC_FS
925 static void snd_card_info_read(struct snd_info_entry *entry,
926 struct snd_info_buffer *buffer)
929 struct snd_card *card;
931 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
932 guard(mutex)(&snd_card_mutex);
933 card = snd_cards[idx];
936 snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
941 snd_iprintf(buffer, " %s\n",
946 snd_iprintf(buffer, "--- no soundcards ---\n");
949 #ifdef CONFIG_SND_OSSEMUL
950 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
953 struct snd_card *card;
955 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
956 guard(mutex)(&snd_card_mutex);
957 card = snd_cards[idx];
960 snd_iprintf(buffer, "%s\n", card->longname);
964 snd_iprintf(buffer, "--- no soundcards ---\n");
970 #ifdef CONFIG_MODULES
971 static void snd_card_module_info_read(struct snd_info_entry *entry,
972 struct snd_info_buffer *buffer)
975 struct snd_card *card;
977 for (idx = 0; idx < SNDRV_CARDS; idx++) {
978 guard(mutex)(&snd_card_mutex);
979 card = snd_cards[idx];
981 snd_iprintf(buffer, "%2i %s\n",
982 idx, card->module->name);
987 int __init snd_card_info_init(void)
989 struct snd_info_entry *entry;
991 entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
994 entry->c.text.read = snd_card_info_read;
995 if (snd_info_register(entry) < 0)
996 return -ENOMEM; /* freed in error path */
998 #ifdef CONFIG_MODULES
999 entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
1002 entry->c.text.read = snd_card_module_info_read;
1003 if (snd_info_register(entry) < 0)
1004 return -ENOMEM; /* freed in error path */
1009 #endif /* CONFIG_SND_PROC_FS */
1012 * snd_component_add - add a component string
1013 * @card: soundcard structure
1014 * @component: the component id string
1016 * This function adds the component id string to the supported list.
1017 * The component can be referred from the alsa-lib.
1019 * Return: Zero otherwise a negative error code.
1022 int snd_component_add(struct snd_card *card, const char *component)
1025 int len = strlen(component);
1027 ptr = strstr(card->components, component);
1029 if (ptr[len] == '\0' || ptr[len] == ' ') /* already there */
1032 if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
1036 if (card->components[0] != '\0')
1037 strcat(card->components, " ");
1038 strcat(card->components, component);
1041 EXPORT_SYMBOL(snd_component_add);
1044 * snd_card_file_add - add the file to the file list of the card
1045 * @card: soundcard structure
1046 * @file: file pointer
1048 * This function adds the file to the file linked-list of the card.
1049 * This linked-list is used to keep tracking the connection state,
1050 * and to avoid the release of busy resources by hotplug.
1052 * Return: zero or a negative error code.
1054 int snd_card_file_add(struct snd_card *card, struct file *file)
1056 struct snd_monitor_file *mfile;
1058 mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
1062 mfile->disconnected_f_op = NULL;
1063 INIT_LIST_HEAD(&mfile->shutdown_list);
1064 guard(spinlock)(&card->files_lock);
1065 if (card->shutdown) {
1069 list_add(&mfile->list, &card->files_list);
1070 get_device(&card->card_dev);
1073 EXPORT_SYMBOL(snd_card_file_add);
1076 * snd_card_file_remove - remove the file from the file list
1077 * @card: soundcard structure
1078 * @file: file pointer
1080 * This function removes the file formerly added to the card via
1081 * snd_card_file_add() function.
1082 * If all files are removed and snd_card_free_when_closed() was
1083 * called beforehand, it processes the pending release of
1086 * Return: Zero or a negative error code.
1088 int snd_card_file_remove(struct snd_card *card, struct file *file)
1090 struct snd_monitor_file *mfile, *found = NULL;
1092 scoped_guard(spinlock, &card->files_lock) {
1093 list_for_each_entry(mfile, &card->files_list, list) {
1094 if (mfile->file == file) {
1095 list_del(&mfile->list);
1096 scoped_guard(spinlock, &shutdown_lock)
1097 list_del(&mfile->shutdown_list);
1098 if (mfile->disconnected_f_op)
1099 fops_put(mfile->disconnected_f_op);
1104 if (list_empty(&card->files_list))
1105 wake_up_all(&card->remove_sleep);
1108 dev_err(card->dev, "card file remove problem (%p)\n", file);
1112 put_device(&card->card_dev);
1115 EXPORT_SYMBOL(snd_card_file_remove);
1119 * snd_power_ref_and_wait - wait until the card gets powered up
1120 * @card: soundcard structure
1122 * Take the power_ref reference count of the given card, and
1123 * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1124 * The refcount is down again while sleeping until power-up, hence this
1125 * function can be used for syncing the floating control ops accesses,
1126 * typically around calling control ops.
1128 * The caller needs to pull down the refcount via snd_power_unref() later
1129 * no matter whether the error is returned from this function or not.
1131 * Return: Zero if successful, or a negative error code.
1133 int snd_power_ref_and_wait(struct snd_card *card)
1135 snd_power_ref(card);
1136 if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1138 wait_event_cmd(card->power_sleep,
1140 snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
1141 snd_power_unref(card), snd_power_ref(card));
1142 return card->shutdown ? -ENODEV : 0;
1144 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
1147 * snd_power_wait - wait until the card gets powered up (old form)
1148 * @card: soundcard structure
1150 * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1152 * Return: Zero if successful, or a negative error code.
1154 int snd_power_wait(struct snd_card *card)
1158 ret = snd_power_ref_and_wait(card);
1159 snd_power_unref(card);
1162 EXPORT_SYMBOL(snd_power_wait);
1163 #endif /* CONFIG_PM */