Initial import

1 files changed, 1040 insertions, 0 deletions

diff --git a/sound/core/init.c b/sound/core/init.c
new file mode 100644
index 000000000..04734e047
--- /dev/null
+++ b/sound/core/init.c
@@ -0,0 +1,1040 @@
+/*
+ *  Initialization routines
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ *
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#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);
+struct snd_card *snd_cards[SNDRV_CARDS];
+EXPORT_SYMBOL(snd_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
+
+#ifdef CONFIG_PROC_FS
+static void snd_card_id_read(struct snd_info_entry *entry,
+			     struct snd_info_buffer *buffer)
+{
+	snd_iprintf(buffer, "%s\n", entry->card->id);
+}
+
+static inline int init_info_for_card(struct snd_card *card)
+{
+	int err;
+	struct snd_info_entry *entry;
+
+	if ((err = snd_info_card_register(card)) < 0) {
+		dev_dbg(card->dev, "unable to create card info\n");
+		return err;
+	}
+	if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
+		dev_dbg(card->dev, "unable to create card entry\n");
+		return err;
+	}
+	entry->c.text.read = snd_card_id_read;
+	if (snd_info_register(entry) < 0) {
+		snd_info_free_entry(entry);
+		entry = NULL;
+	}
+	card->proc_id = entry;
+	return 0;
+}
+#else /* !CONFIG_PROC_FS */
+#define init_info_for_card(card)
+#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\n",
+			 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;
+	card->module = module;
+	INIT_LIST_HEAD(&card->devices);
+	init_rwsem(&card->controls_rwsem);
+	rwlock_init(&card->ctl_files_rwlock);
+	mutex_init(&card->user_ctl_lock);
+	INIT_LIST_HEAD(&card->controls);
+	INIT_LIST_HEAD(&card->ctl_files);
+	spin_lock_init(&card->files_lock);
+	INIT_LIST_HEAD(&card->files_list);
+#ifdef CONFIG_PM
+	mutex_init(&card->power_lock);
+	init_waitqueue_head(&card->power_sleep);
+#endif
+
+	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;
+
+	/* 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;
+	}
+	*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);
+
+/* 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 unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
+{
+	return POLLERR | POLLNVAL;
+}
+
+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);
+
+	/* phase 1: 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);
+	
+	/* phase 2: 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);	
+
+	/* phase 3: 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;
+	}
+#ifdef CONFIG_PM
+	wake_up(&card->power_sleep);
+#endif
+	return 0;	
+}
+
+EXPORT_SYMBOL(snd_card_disconnect);
+
+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);
+	snd_info_free_entry(card->proc_id);
+	if (snd_info_card_free(card) < 0) {
+		dev_warn(card->dev, "unable to free card info\n");
+		/* 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)
+{
+	struct completion released;
+	int ret;
+
+	init_completion(&released);
+	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)
+		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 snprintf(buf, PAGE_SIZE, "%s\n", 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, S_IRUGO | S_IWUSR, 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 snprintf(buf, PAGE_SIZE, "%i\n", card->number);
+}
+
+static DEVICE_ATTR(number, S_IRUGO, 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\n");
+	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 0;
+	}
+	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);
+	init_info_for_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_REGISTER);
+#endif
+	return 0;
+}
+
+EXPORT_SYMBOL(snd_card_register);
+
+#ifdef CONFIG_PROC_FS
+static struct snd_info_entry *snd_card_info_entry;
+
+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\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);
+		if ((card = snd_cards[idx]) != NULL) {
+			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 struct snd_info_entry *snd_card_module_info_entry;
+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\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) {
+		snd_info_free_entry(entry);
+		return -ENOMEM;
+	}
+	snd_card_info_entry = entry;
+
+#ifdef MODULE
+	entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
+	if (entry) {
+		entry->c.text.read = snd_card_module_info_read;
+		if (snd_info_register(entry) < 0)
+			snd_info_free_entry(entry);
+		else
+			snd_card_module_info_entry = entry;
+	}
+#endif
+
+	return 0;
+}
+
+int __exit snd_card_info_done(void)
+{
+	snd_info_free_entry(snd_card_info_entry);
+#ifdef MODULE
+	snd_info_free_entry(snd_card_module_info_entry);
+#endif
+	return 0;
+}
+
+#endif /* CONFIG_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;
+		}
+	}
+	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_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.
+ *
+ *  Note: the power lock must be active before call.
+ */
+int snd_power_wait(struct snd_card *card, unsigned int power_state)
+{
+	wait_queue_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);
+		snd_power_unlock(card);
+		schedule_timeout(30 * HZ);
+		snd_power_lock(card);
+	}
+	remove_wait_queue(&card->power_sleep, &wait);
+	return result;
+}
+
+EXPORT_SYMBOL(snd_power_wait);
+#endif /* CONFIG_PM */