// 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/completion.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_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

   *
   *  Creates and initializes a soundcard structure.
   *

   *  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;

  	if (extra_size > 0)
  		card->private_data = (char *)card + sizeof(struct snd_card);

  	if (xid)

  		strlcpy(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
  ",

  			 idx, snd_ecards_limit - 1, err);

  		kfree(card);
  		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);
  	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);
  #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
  ");

  		goto __error;
  	}

  	err = snd_info_card_create(card);
  	if (err < 0) {

  		dev_err(parent, "unable to create card info
  ");

  		goto __error_ctl;
  	}

  	*card_ret = card;
  	return 0;

  
        __error_ctl:

  	snd_device_free_all(card);

        __error:

  	put_device(&card->card_dev);

    	return err;

  }

  EXPORT_SYMBOL(snd_card_new);

  /**
   * 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().
   */
  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;
  	spin_unlock(&card->files_lock);

  	/* replace file->f_op with special dummy operations */

  	spin_lock(&card->files_lock);

  	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);

  	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);
  #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
  ",
  			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)

  {

  #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
  ");

  		/* Not fatal error */
  	}

  	if (card->release_completion)
  		complete(card->release_completion);

  	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.
   */

  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;

  	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)
  ", id);

  	if (card->proc_root->name)

  		strlcpy(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
  card_id_show_attr(struct device *dev,
  		  struct device_attribute *attr, char *buf)
  {

  	struct snd_card *card = container_of(dev, struct snd_card, card_dev);

  	return scnprintf(buf, PAGE_SIZE, "%s
  ", card->id);

  }
  
  static ssize_t
  card_id_store_attr(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(id, 0644, card_id_show_attr, card_id_store_attr);

  
  static ssize_t
  card_number_show_attr(struct device *dev,
  		     struct device_attribute *attr, char *buf)
  {

  	struct snd_card *card = container_of(dev, struct snd_card, card_dev);

  	return scnprintf(buf, PAGE_SIZE, "%i
  ", card->number);

  }

  static DEVICE_ATTR(number, 0444, card_number_show_attr, NULL);

  
  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
   */
  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
  ");
  	return -ENOSPC;

  }

  EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);

  /**
   *  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;

  	}

  	if ((err = snd_device_register_all(card)) < 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);

  		if ((card = snd_cards[idx]) != NULL) {
  			count++;

  			snd_iprintf(buffer, "%2i [%-15s]: %s - %s
  ",

  					idx,
  					card->id,
  					card->driver,
  					card->shortname);

  			snd_iprintf(buffer, "                      %s
  ",

  					card->longname);
  		}

  		mutex_unlock(&snd_card_mutex);

  	}
  	if (!count)
  		snd_iprintf(buffer, "--- no soundcards ---
  ");
  }

  #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);

  		if ((card = snd_cards[idx]) != NULL) {
  			count++;
  			snd_iprintf(buffer, "%s
  ", card->longname);
  		}

  		mutex_unlock(&snd_card_mutex);

  	}
  	if (!count) {
  		snd_iprintf(buffer, "--- no soundcards ---
  ");
  	}
  }
  
  #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);

  		if ((card = snd_cards[idx]) != NULL)

  			snd_iprintf(buffer, "%2i %s
  ",
  				    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)
  ", file);

  		return -ENOENT;
  	}

  	kfree(found);

  	put_device(&card->card_dev);

  	return 0;
  }

  EXPORT_SYMBOL(snd_card_file_remove);

  #ifdef CONFIG_PM
  /**
   *  snd_power_wait - wait until the power-state is changed.
   *  @card: soundcard structure
   *  @power_state: expected power state

   *
   *  Waits until the power-state is changed.
   *

   *  Return: Zero if successful, or a negative error code.

   */

  int snd_power_wait(struct snd_card *card, unsigned int power_state)

  {

  	wait_queue_entry_t wait;

  	int result = 0;
  
  	/* fastpath */
  	if (snd_power_get_state(card) == power_state)
  		return 0;
  	init_waitqueue_entry(&wait, current);
  	add_wait_queue(&card->power_sleep, &wait);
  	while (1) {
  		if (card->shutdown) {
  			result = -ENODEV;
  			break;
  		}
  		if (snd_power_get_state(card) == power_state)
  			break;

  		set_current_state(TASK_UNINTERRUPTIBLE);

  		schedule_timeout(30 * HZ);

  	}
  	remove_wait_queue(&card->power_sleep, &wait);
  	return result;
  }

  EXPORT_SYMBOL(snd_power_wait);

  #endif /* CONFIG_PM */