init.c

linux 内核源代码

		card->free_on_last_close = 1;
	spin_unlock(&card->files_lock);

	if (free_now)
		snd_card_do_free(card);
	return 0;
}

EXPORT_SYMBOL(snd_card_free_when_closed);

int snd_card_free(struct snd_card *card)
{
	int ret = snd_card_free_prepare(card);
	if (ret)
		return ret;

	/* wait, until all devices are ready for the free operation */
	wait_event(card->shutdown_sleep, card->files == NULL);
	snd_card_do_free(card);
	return 0;
}

EXPORT_SYMBOL(snd_card_free);

static void choose_default_id(struct snd_card *card)
{
	int i, len, idx_flag = 0, loops = SNDRV_CARDS;
	char *id, *spos;
	
	id = spos = card->shortname;	
	while (*id != '\0') {
		if (*id == ' ')
			spos = id + 1;
		id++;
	}
	id = card->id;
	while (*spos != '\0' && !isalnum(*spos))
		spos++;
	if (isdigit(*spos))
		*id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
	while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
		if (isalnum(*spos))
			*id++ = *spos;
		spos++;
	}
	*id = '\0';

	id = card->id;
	
	if (*id == '\0')
		strcpy(id, "default");

	while (1) {
	      	if (loops-- == 0) {
      			snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
      			strcpy(card->id, card->proc_root->name);
      			return;
      		}
	      	if (!snd_info_check_reserved_words(id))
      			goto __change;
		for (i = 0; i < snd_ecards_limit; i++) {
			if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
				goto __change;
		}
		break;

	      __change:
		len = strlen(id);
		if (idx_flag) {
			if (id[len-1] != '9')
				id[len-1]++;
			else
				id[len-1] = 'A';
		} else if ((size_t)len <= sizeof(card->id) - 3) {
			strcat(id, "_1");
			idx_flag++;
		} else {
			spos = id + len - 2;
			if ((size_t)len <= sizeof(card->id) - 2)
				spos++;
			*spos++ = '_';
			*spos++ = '1';
			*spos++ = '\0';
			idx_flag++;
		}
	}
}

/**
 *  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.
 *
 *  Returns zero otherwise a negative error code if the registrain failed.
 */
int snd_card_register(struct snd_card *card)
{
	int err;

	snd_assert(card != NULL, return -EINVAL);
#ifndef CONFIG_SYSFS_DEPRECATED
	if (!card->card_dev) {
		card->card_dev = device_create(sound_class, card->dev, 0,
					       "card%i", card->number);
		if (IS_ERR(card->card_dev))
			card->card_dev = NULL;
	}
#endif
	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[0] == '\0')
		choose_default_id(card);
	snd_cards[card->number] = card;
	mutex_unlock(&snd_card_mutex);
	init_info_for_card(card);
#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	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.
 *
 *  Returns 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.
 *
 *  Returns 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;
	mfile->next = NULL;
	spin_lock(&card->files_lock);
	if (card->shutdown) {
		spin_unlock(&card->files_lock);
		kfree(mfile);
		return -ENODEV;
	}
	mfile->next = card->files;
	card->files = mfile;
	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.
 *
 *  Returns zero or a negative error code.
 */
int snd_card_file_remove(struct snd_card *card, struct file *file)
{
	struct snd_monitor_file *mfile, *pfile = NULL;
	int last_close = 0;

	spin_lock(&card->files_lock);
	mfile = card->files;
	while (mfile) {
		if (mfile->file == file) {
			if (pfile)
				pfile->next = mfile->next;
			else
				card->files = mfile->next;
			break;
		}
		pfile = mfile;
		mfile = mfile->next;
	}
	if (mfile && mfile->disconnected_f_op) {
		fops_put(mfile->disconnected_f_op);
		spin_lock(&shutdown_lock);
		list_del(&mfile->shutdown_list);
		spin_unlock(&shutdown_lock);
	}
	if (card->files == NULL)
		last_close = 1;
	spin_unlock(&card->files_lock);
	if (last_close) {
		wake_up(&card->shutdown_sleep);
		if (card->free_on_last_close)
			snd_card_do_free(card);
	}
	if (!mfile) {
		snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
		return -ENOENT;
	}
	kfree(mfile);
	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.
 *
 *  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 */