/*
   *  Information interface for ALSA driver

   *  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/time.h>

  #include <linux/mm.h>

  #include <linux/slab.h>

  #include <linux/string.h>

  #include <linux/module.h>

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

  #include <linux/utsname.h>

  #include <linux/proc_fs.h>

  #include <linux/mutex.h>

  #include <stdarg.h>
  
  /*
   *
   */

  #ifdef CONFIG_PROC_FS

  int snd_info_check_reserved_words(const char *str)
  {
  	static char *reserved[] =
  	{
  		"version",
  		"meminfo",
  		"memdebug",
  		"detect",
  		"devices",
  		"oss",
  		"cards",
  		"timers",
  		"synth",
  		"pcm",
  		"seq",
  		NULL
  	};
  	char **xstr = reserved;
  
  	while (*xstr) {
  		if (!strcmp(*xstr, str))
  			return 0;
  		xstr++;
  	}
  	if (!strncmp(str, "card", 4))
  		return 0;
  	return 1;
  }

  static DEFINE_MUTEX(info_mutex);

  struct snd_info_private_data {
  	struct snd_info_buffer *rbuffer;
  	struct snd_info_buffer *wbuffer;
  	struct snd_info_entry *entry;

  	void *file_private_data;

  };

  
  static int snd_info_version_init(void);
  static int snd_info_version_done(void);

  static void snd_info_disconnect(struct snd_info_entry *entry);

  /* resize the proc r/w buffer */
  static int resize_info_buffer(struct snd_info_buffer *buffer,
  			      unsigned int nsize)
  {
  	char *nbuf;
  
  	nsize = PAGE_ALIGN(nsize);

  	nbuf = krealloc(buffer->buffer, nsize, GFP_KERNEL | __GFP_ZERO);

  	if (! nbuf)
  		return -ENOMEM;

  	buffer->buffer = nbuf;
  	buffer->len = nsize;
  	return 0;
  }

  /**
   * snd_iprintf - printf on the procfs buffer
   * @buffer: the procfs buffer
   * @fmt: the printf format
   *
   * Outputs the string on the procfs buffer just like printf().
   *

   * Return: The size of output string, or a negative error code.

   */

  int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)

  {
  	va_list args;
  	int len, res;

  	int err = 0;

  	might_sleep();

  	if (buffer->stop || buffer->error)
  		return 0;
  	len = buffer->len - buffer->size;
  	va_start(args, fmt);

  	for (;;) {

  		va_list ap;
  		va_copy(ap, args);
  		res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
  		va_end(ap);

  		if (res < len)
  			break;
  		err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
  		if (err < 0)
  			break;
  		len = buffer->len - buffer->size;

  	}

  	va_end(args);
  
  	if (err < 0)
  		return err;

  	buffer->curr += res;
  	buffer->size += res;
  	return res;
  }

  EXPORT_SYMBOL(snd_iprintf);

  /*
  
   */

  static struct proc_dir_entry *snd_proc_root;
  struct snd_info_entry *snd_seq_root;

  EXPORT_SYMBOL(snd_seq_root);

  #ifdef CONFIG_SND_OSSEMUL

  struct snd_info_entry *snd_oss_root;

  #endif

  static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
  {

  	struct snd_info_private_data *data;

  	struct snd_info_entry *entry;

  	loff_t ret = -EINVAL, size;

  
  	data = file->private_data;
  	entry = data->entry;

  	mutex_lock(&entry->access);

  	if (entry->content == SNDRV_INFO_CONTENT_DATA &&
  	    entry->c.ops->llseek) {
  		offset = entry->c.ops->llseek(entry,
  					      data->file_private_data,
  					      file, offset, orig);
  		goto out;
  	}
  	if (entry->content == SNDRV_INFO_CONTENT_DATA)
  		size = entry->size;
  	else
  		size = 0;
  	switch (orig) {
  	case SEEK_SET:
  		break;
  	case SEEK_CUR:
  		offset += file->f_pos;

  		break;

  	case SEEK_END:
  		if (!size)

  			goto out;

  		offset += size;

  		break;

  	default:
  		goto out;

  	}

  	if (offset < 0)
  		goto out;
  	if (size && offset > size)
  		offset = size;
  	file->f_pos = offset;
  	ret = offset;
   out:

  	mutex_unlock(&entry->access);

  	return ret;
  }
  
  static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
  				   size_t count, loff_t * offset)
  {

  	struct snd_info_private_data *data;

  	struct snd_info_entry *entry;

  	struct snd_info_buffer *buf;

  	size_t size = 0;
  	loff_t pos;
  
  	data = file->private_data;

  	if (snd_BUG_ON(!data))
  		return -ENXIO;

  	pos = *offset;
  	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
  		return -EIO;
  	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
  		return -EIO;
  	entry = data->entry;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_TEXT:
  		buf = data->rbuffer;
  		if (buf == NULL)
  			return -EIO;
  		if (pos >= buf->size)
  			return 0;
  		size = buf->size - pos;
  		size = min(count, size);
  		if (copy_to_user(buffer, buf->buffer + pos, size))
  			return -EFAULT;
  		break;
  	case SNDRV_INFO_CONTENT_DATA:

  		if (pos >= entry->size)
  			return 0;
  		if (entry->c.ops->read) {
  			size = entry->size - pos;
  			size = min(count, size);

  			size = entry->c.ops->read(entry,
  						  data->file_private_data,

  						  file, buffer, size, pos);
  		}

  		break;
  	}
  	if ((ssize_t) size > 0)
  		*offset = pos + size;
  	return size;
  }
  
  static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
  				    size_t count, loff_t * offset)
  {

  	struct snd_info_private_data *data;

  	struct snd_info_entry *entry;

  	struct snd_info_buffer *buf;

  	ssize_t size = 0;

  	loff_t pos;
  
  	data = file->private_data;

  	if (snd_BUG_ON(!data))
  		return -ENXIO;

  	entry = data->entry;
  	pos = *offset;
  	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
  		return -EIO;
  	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
  		return -EIO;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_TEXT:
  		buf = data->wbuffer;
  		if (buf == NULL)
  			return -EIO;

  		mutex_lock(&entry->access);

  		if (pos + count >= buf->len) {
  			if (resize_info_buffer(buf, pos + count)) {
  				mutex_unlock(&entry->access);
  				return -ENOMEM;
  			}
  		}
  		if (copy_from_user(buf->buffer + pos, buffer, count)) {
  			mutex_unlock(&entry->access);

  			return -EFAULT;

  		}
  		buf->size = pos + count;
  		mutex_unlock(&entry->access);
  		size = count;

  		break;
  	case SNDRV_INFO_CONTENT_DATA:

  		if (entry->c.ops->write && count > 0) {
  			size_t maxsize = entry->size - pos;
  			count = min(count, maxsize);

  			size = entry->c.ops->write(entry,
  						   data->file_private_data,
  						   file, buffer, count, pos);

  		}

  		break;
  	}
  	if ((ssize_t) size > 0)
  		*offset = pos + size;
  	return size;
  }
  
  static int snd_info_entry_open(struct inode *inode, struct file *file)
  {

  	struct snd_info_entry *entry;
  	struct snd_info_private_data *data;
  	struct snd_info_buffer *buffer;

  	int mode, err;

  	mutex_lock(&info_mutex);

  	entry = PDE_DATA(inode);

  	if (entry == NULL || ! entry->p) {

  		mutex_unlock(&info_mutex);

  		return -ENODEV;
  	}
  	if (!try_module_get(entry->module)) {
  		err = -EFAULT;
  		goto __error1;
  	}
  	mode = file->f_flags & O_ACCMODE;
  	if (mode == O_RDONLY || mode == O_RDWR) {

  		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&

  		     entry->c.ops->read == NULL)) {
  		    	err = -ENODEV;
  		    	goto __error;
  		}
  	}
  	if (mode == O_WRONLY || mode == O_RDWR) {

  		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&

  		     entry->c.ops->write == NULL)) {
  		    	err = -ENODEV;
  		    	goto __error;
  		}
  	}

  	data = kzalloc(sizeof(*data), GFP_KERNEL);

  	if (data == NULL) {
  		err = -ENOMEM;
  		goto __error;
  	}
  	data->entry = entry;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_TEXT:
  		if (mode == O_RDONLY || mode == O_RDWR) {

  			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);

  			if (buffer == NULL)
  				goto __nomem;

  			data->rbuffer = buffer;

  			buffer->len = PAGE_SIZE;

  			buffer->buffer = kzalloc(buffer->len, GFP_KERNEL);

  			if (buffer->buffer == NULL)
  				goto __nomem;

  		}
  		if (mode == O_WRONLY || mode == O_RDWR) {

  			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);

  			if (buffer == NULL)
  				goto __nomem;

  			data->wbuffer = buffer;

  			buffer->len = PAGE_SIZE;
  			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
  			if (buffer->buffer == NULL)
  				goto __nomem;

  		}
  		break;
  	case SNDRV_INFO_CONTENT_DATA:	/* data */
  		if (entry->c.ops->open) {
  			if ((err = entry->c.ops->open(entry, mode,
  						      &data->file_private_data)) < 0) {
  				kfree(data);
  				goto __error;
  			}
  		}
  		break;
  	}
  	file->private_data = data;

  	mutex_unlock(&info_mutex);

  	if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
  	    (mode == O_RDONLY || mode == O_RDWR)) {
  		if (entry->c.text.read) {

  			mutex_lock(&entry->access);

  			entry->c.text.read(entry, data->rbuffer);

  			mutex_unlock(&entry->access);

  		}
  	}
  	return 0;

   __nomem:
  	if (data->rbuffer) {
  		kfree(data->rbuffer->buffer);
  		kfree(data->rbuffer);
  	}
  	if (data->wbuffer) {
  		kfree(data->wbuffer->buffer);
  		kfree(data->wbuffer);
  	}
  	kfree(data);
  	err = -ENOMEM;

        __error:
  	module_put(entry->module);
        __error1:

  	mutex_unlock(&info_mutex);

  	return err;
  }
  
  static int snd_info_entry_release(struct inode *inode, struct file *file)
  {

  	struct snd_info_entry *entry;
  	struct snd_info_private_data *data;

  	int mode;
  
  	mode = file->f_flags & O_ACCMODE;
  	data = file->private_data;
  	entry = data->entry;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_TEXT:

  		if (data->rbuffer) {
  			kfree(data->rbuffer->buffer);

  			kfree(data->rbuffer);
  		}

  		if (data->wbuffer) {

  			if (entry->c.text.write) {
  				entry->c.text.write(entry, data->wbuffer);
  				if (data->wbuffer->error) {

  					if (entry->card)
  						dev_warn(entry->card->dev, "info: data write error to %s (%i)
  ",
  							 entry->name,
  							 data->wbuffer->error);
  					else
  						pr_warn("ALSA: info: data write error to %s (%i)
  ",
  							entry->name,
  							data->wbuffer->error);

  				}
  			}

  			kfree(data->wbuffer->buffer);

  			kfree(data->wbuffer);
  		}
  		break;
  	case SNDRV_INFO_CONTENT_DATA:
  		if (entry->c.ops->release)
  			entry->c.ops->release(entry, mode,
  					      data->file_private_data);
  		break;
  	}
  	module_put(entry->module);
  	kfree(data);
  	return 0;
  }
  
  static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
  {

  	struct snd_info_private_data *data;

  	struct snd_info_entry *entry;
  	unsigned int mask;
  
  	data = file->private_data;
  	if (data == NULL)
  		return 0;
  	entry = data->entry;
  	mask = 0;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_DATA:
  		if (entry->c.ops->poll)
  			return entry->c.ops->poll(entry,
  						  data->file_private_data,
  						  file, wait);
  		if (entry->c.ops->read)
  			mask |= POLLIN | POLLRDNORM;
  		if (entry->c.ops->write)
  			mask |= POLLOUT | POLLWRNORM;
  		break;
  	}
  	return mask;
  }

  static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
  				unsigned long arg)

  {

  	struct snd_info_private_data *data;

  	struct snd_info_entry *entry;
  
  	data = file->private_data;
  	if (data == NULL)
  		return 0;
  	entry = data->entry;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_DATA:
  		if (entry->c.ops->ioctl)
  			return entry->c.ops->ioctl(entry,
  						   data->file_private_data,
  						   file, cmd, arg);
  		break;
  	}
  	return -ENOTTY;
  }

  static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
  {

  	struct inode *inode = file_inode(file);

  	struct snd_info_private_data *data;

  	struct snd_info_entry *entry;
  
  	data = file->private_data;
  	if (data == NULL)
  		return 0;
  	entry = data->entry;
  	switch (entry->content) {
  	case SNDRV_INFO_CONTENT_DATA:
  		if (entry->c.ops->mmap)
  			return entry->c.ops->mmap(entry,
  						  data->file_private_data,
  						  inode, file, vma);
  		break;
  	}
  	return -ENXIO;
  }

  static const struct file_operations snd_info_entry_operations =

  {

  	.owner =		THIS_MODULE,
  	.llseek =		snd_info_entry_llseek,
  	.read =			snd_info_entry_read,
  	.write =		snd_info_entry_write,
  	.poll =			snd_info_entry_poll,
  	.unlocked_ioctl =	snd_info_entry_ioctl,
  	.mmap =			snd_info_entry_mmap,
  	.open =			snd_info_entry_open,
  	.release =		snd_info_entry_release,

  };

  int __init snd_info_init(void)
  {
  	struct proc_dir_entry *p;

  	p = proc_mkdir("asound", NULL);

  	if (p == NULL)
  		return -ENOMEM;
  	snd_proc_root = p;
  #ifdef CONFIG_SND_OSSEMUL
  	{

  		struct snd_info_entry *entry;

  		if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
  			return -ENOMEM;
  		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
  		if (snd_info_register(entry) < 0) {
  			snd_info_free_entry(entry);
  			return -ENOMEM;
  		}
  		snd_oss_root = entry;
  	}
  #endif

  #if IS_ENABLED(CONFIG_SND_SEQUENCER)

  	{

  		struct snd_info_entry *entry;

  		if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
  			return -ENOMEM;
  		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
  		if (snd_info_register(entry) < 0) {
  			snd_info_free_entry(entry);
  			return -ENOMEM;
  		}
  		snd_seq_root = entry;
  	}
  #endif
  	snd_info_version_init();

  	snd_minor_info_init();
  	snd_minor_info_oss_init();
  	snd_card_info_init();
  	return 0;
  }
  
  int __exit snd_info_done(void)
  {
  	snd_card_info_done();
  	snd_minor_info_oss_done();
  	snd_minor_info_done();

  	snd_info_version_done();
  	if (snd_proc_root) {

  #if IS_ENABLED(CONFIG_SND_SEQUENCER)

  		snd_info_free_entry(snd_seq_root);

  #endif
  #ifdef CONFIG_SND_OSSEMUL

  		snd_info_free_entry(snd_oss_root);

  #endif

  		proc_remove(snd_proc_root);

  	}
  	return 0;
  }
  
  /*
  
   */
  
  
  /*
   * create a card proc file
   * called from init.c
   */

  int snd_info_card_create(struct snd_card *card)

  {
  	char str[8];

  	struct snd_info_entry *entry;

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

  
  	sprintf(str, "card%i", card->number);
  	if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
  		return -ENOMEM;
  	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
  	if (snd_info_register(entry) < 0) {
  		snd_info_free_entry(entry);
  		return -ENOMEM;
  	}
  	card->proc_root = entry;
  	return 0;
  }
  
  /*
   * register the card proc file
   * called from init.c
   */

  int snd_info_card_register(struct snd_card *card)

  {
  	struct proc_dir_entry *p;

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

  
  	if (!strcmp(card->id, card->proc_root->name))
  		return 0;
  
  	p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
  	if (p == NULL)
  		return -ENOMEM;
  	card->proc_root_link = p;
  	return 0;
  }
  
  /*

   * called on card->id change
   */
  void snd_info_card_id_change(struct snd_card *card)
  {
  	mutex_lock(&info_mutex);
  	if (card->proc_root_link) {

  		proc_remove(card->proc_root_link);

  		card->proc_root_link = NULL;
  	}
  	if (strcmp(card->id, card->proc_root->name))
  		card->proc_root_link = proc_symlink(card->id,
  						    snd_proc_root,
  						    card->proc_root->name);
  	mutex_unlock(&info_mutex);
  }
  
  /*

   * de-register the card proc file
   * called from init.c
   */

  void snd_info_card_disconnect(struct snd_card *card)

  {

  	if (!card)
  		return;

  	mutex_lock(&info_mutex);

  	proc_remove(card->proc_root_link);
  	card->proc_root_link = NULL;

  	if (card->proc_root)
  		snd_info_disconnect(card->proc_root);
  	mutex_unlock(&info_mutex);
  }
  
  /*
   * release the card proc file resources
   * called from init.c
   */
  int snd_info_card_free(struct snd_card *card)
  {

  	if (!card)
  		return 0;

  	snd_info_free_entry(card->proc_root);
  	card->proc_root = NULL;

  	return 0;
  }
  
  
  /**
   * snd_info_get_line - read one line from the procfs buffer
   * @buffer: the procfs buffer
   * @line: the buffer to store

   * @len: the max. buffer size

   *
   * Reads one line from the buffer and stores the string.
   *

   * Return: Zero if successful, or 1 if error or EOF.

   */

  int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)

  {
  	int c = -1;

  	if (snd_BUG_ON(!buffer || !buffer->buffer))
  		return 1;

  	if (len <= 0 || buffer->stop || buffer->error)
  		return 1;

  	while (!buffer->stop) {

  		c = buffer->buffer[buffer->curr++];

  		if (buffer->curr >= buffer->size)

  			buffer->stop = 1;

  		if (c == '
  ')

  			break;

  		if (len > 1) {

  			len--;
  			*line++ = c;

  		}
  	}

  	*line = '\0';
  	return 0;
  }

  EXPORT_SYMBOL(snd_info_get_line);

  /**

   * snd_info_get_str - parse a string token

   * @dest: the buffer to store the string token
   * @src: the original string
   * @len: the max. length of token - 1
   *
   * Parses the original string and copy a token to the given
   * string buffer.
   *

   * Return: The updated pointer of the original string so that

   * it can be used for the next call.
   */

  const char *snd_info_get_str(char *dest, const char *src, int len)

  {
  	int c;
  
  	while (*src == ' ' || *src == '\t')
  		src++;
  	if (*src == '"' || *src == '\'') {
  		c = *src++;
  		while (--len > 0 && *src && *src != c) {
  			*dest++ = *src++;
  		}
  		if (*src == c)
  			src++;
  	} else {
  		while (--len > 0 && *src && *src != ' ' && *src != '\t') {
  			*dest++ = *src++;
  		}
  	}
  	*dest = 0;
  	while (*src == ' ' || *src == '\t')
  		src++;
  	return src;
  }

  EXPORT_SYMBOL(snd_info_get_str);

  /**
   * snd_info_create_entry - create an info entry
   * @name: the proc file name
   *
   * Creates an info entry with the given file name and initializes as
   * the default state.
   *
   * Usually called from other functions such as
   * snd_info_create_card_entry().
   *

   * Return: The pointer of the new instance, or %NULL on failure.

   */

  static struct snd_info_entry *snd_info_create_entry(const char *name)

  {

  	struct snd_info_entry *entry;

  	entry = kzalloc(sizeof(*entry), GFP_KERNEL);

  	if (entry == NULL)
  		return NULL;

  	entry->name = kstrdup(name, GFP_KERNEL);

  	if (entry->name == NULL) {
  		kfree(entry);
  		return NULL;
  	}
  	entry->mode = S_IFREG | S_IRUGO;
  	entry->content = SNDRV_INFO_CONTENT_TEXT;

  	mutex_init(&entry->access);

  	INIT_LIST_HEAD(&entry->children);
  	INIT_LIST_HEAD(&entry->list);

  	return entry;
  }
  
  /**
   * snd_info_create_module_entry - create an info entry for the given module
   * @module: the module pointer
   * @name: the file name
   * @parent: the parent directory
   *
   * Creates a new info entry and assigns it to the given module.
   *

   * Return: The pointer of the new instance, or %NULL on failure.

   */

  struct snd_info_entry *snd_info_create_module_entry(struct module * module,

  					       const char *name,

  					       struct snd_info_entry *parent)

  {

  	struct snd_info_entry *entry = snd_info_create_entry(name);

  	if (entry) {
  		entry->module = module;
  		entry->parent = parent;
  	}
  	return entry;
  }

  EXPORT_SYMBOL(snd_info_create_module_entry);

  /**
   * snd_info_create_card_entry - create an info entry for the given card
   * @card: the card instance
   * @name: the file name
   * @parent: the parent directory
   *
   * Creates a new info entry and assigns it to the given card.
   *

   * Return: The pointer of the new instance, or %NULL on failure.

   */

  struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,

  					     const char *name,

  					     struct snd_info_entry * parent)

  {

  	struct snd_info_entry *entry = snd_info_create_entry(name);

  	if (entry) {
  		entry->module = card->module;
  		entry->card = card;
  		entry->parent = parent;
  	}
  	return entry;
  }

  EXPORT_SYMBOL(snd_info_create_card_entry);

  static void snd_info_disconnect(struct snd_info_entry *entry)

  {

  	struct list_head *p, *n;
  	struct proc_dir_entry *root;

  	list_for_each_safe(p, n, &entry->children) {
  		snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
  	}
  
  	if (! entry->p)
  		return;
  	list_del_init(&entry->list);
  	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;

  	snd_BUG_ON(!root);

  	proc_remove(entry->p);

  	entry->p = NULL;

  }

  static int snd_info_dev_free_entry(struct snd_device *device)

  {

  	struct snd_info_entry *entry = device->device_data;

  	snd_info_free_entry(entry);

  	return 0;
  }

  static int snd_info_dev_register_entry(struct snd_device *device)

  {

  	struct snd_info_entry *entry = device->device_data;

  	return snd_info_register(entry);

  }
  
  /**
   * snd_card_proc_new - create an info entry for the given card
   * @card: the card instance
   * @name: the file name
   * @entryp: the pointer to store the new info entry
   *
   * Creates a new info entry and assigns it to the given card.
   * Unlike snd_info_create_card_entry(), this function registers the
   * info entry as an ALSA device component, so that it can be
   * unregistered/released without explicit call.
   * Also, you don't have to register this entry via snd_info_register(),
   * since this will be registered by snd_card_register() automatically.
   *
   * The parent is assumed as card->proc_root.
   *
   * For releasing this entry, use snd_device_free() instead of
   * snd_info_free_entry(). 
   *

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

   */

  int snd_card_proc_new(struct snd_card *card, const char *name,
  		      struct snd_info_entry **entryp)

  {

  	static struct snd_device_ops ops = {

  		.dev_free = snd_info_dev_free_entry,
  		.dev_register =	snd_info_dev_register_entry,

  		/* disconnect is done via snd_info_card_disconnect() */

  	};

  	struct snd_info_entry *entry;

  	int err;
  
  	entry = snd_info_create_card_entry(card, name, card->proc_root);
  	if (! entry)
  		return -ENOMEM;
  	if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
  		snd_info_free_entry(entry);
  		return err;
  	}
  	if (entryp)
  		*entryp = entry;
  	return 0;
  }

  EXPORT_SYMBOL(snd_card_proc_new);

  /**
   * snd_info_free_entry - release the info entry
   * @entry: the info entry
   *
   * Releases the info entry.  Don't call this after registered.
   */

  void snd_info_free_entry(struct snd_info_entry * entry)

  {
  	if (entry == NULL)
  		return;

  	if (entry->p) {
  		mutex_lock(&info_mutex);
  		snd_info_disconnect(entry);
  		mutex_unlock(&info_mutex);
  	}

  	kfree(entry->name);
  	if (entry->private_free)
  		entry->private_free(entry);
  	kfree(entry);
  }

  EXPORT_SYMBOL(snd_info_free_entry);

  /**
   * snd_info_register - register the info entry
   * @entry: the info entry
   *
   * Registers the proc info entry.
   *

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

   */

  int snd_info_register(struct snd_info_entry * entry)

  {
  	struct proc_dir_entry *root, *p = NULL;

  	if (snd_BUG_ON(!entry))
  		return -ENXIO;

  	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;

  	mutex_lock(&info_mutex);

  	if (S_ISDIR(entry->mode)) {
  		p = proc_mkdir_mode(entry->name, entry->mode, root);
  		if (!p) {
  			mutex_unlock(&info_mutex);
  			return -ENOMEM;
  		}
  	} else {
  		p = proc_create_data(entry->name, entry->mode, root,
  					&snd_info_entry_operations, entry);
  		if (!p) {
  			mutex_unlock(&info_mutex);
  			return -ENOMEM;
  		}

  		proc_set_size(p, entry->size);

  	}

  	entry->p = p;

  	if (entry->parent)
  		list_add_tail(&entry->list, &entry->parent->children);

  	mutex_unlock(&info_mutex);

  	return 0;
  }

  EXPORT_SYMBOL(snd_info_register);

  /*
  
   */

  static struct snd_info_entry *snd_info_version_entry;

  static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)

  {
  	snd_iprintf(buffer,

  		    "Advanced Linux Sound Architecture Driver Version k%s.
  ",
  		    init_utsname()->release);

  }
  
  static int __init snd_info_version_init(void)
  {

  	struct snd_info_entry *entry;

  
  	entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
  	if (entry == NULL)
  		return -ENOMEM;

  	entry->c.text.read = snd_info_version_read;
  	if (snd_info_register(entry) < 0) {
  		snd_info_free_entry(entry);
  		return -ENOMEM;
  	}
  	snd_info_version_entry = entry;
  	return 0;
  }
  
  static int __exit snd_info_version_done(void)
  {

  	snd_info_free_entry(snd_info_version_entry);

  	return 0;
  }
  
  #endif /* CONFIG_PROC_FS */