init.c

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/*
 *  Initialization routines
 *  Copyright (c) by Jaroslav Kysela <[email protected]>
 *
 *
 *   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 <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;

static unsigned int snd_cards_lock; /* locked for registering/using */
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 defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
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) {
        snd_printd("unable to create card info\n");
        return err;
    }
    if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
        snd_printd("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

int snd_card_create(int idx, const char *xid,
            struct module *module, int extra_size,
            struct snd_card **card_ret)
{
    struct snd_card *card;
    int err, idx2;

    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 (xid)
        strlcpy(card->id, xid, sizeof(card->id));
    err = 0;
    mutex_lock(&snd_card_mutex);
    if (idx < 0) {
        for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
            /* idx == -1 == 0xffff means: take any free slot */
            if (~snd_cards_lock & idx & 1<<idx2) {
                if (module_slot_match(module, idx2)) {
                    idx = idx2;
                    break;
                }
            }
    }
    if (idx < 0) {
        for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
            /* idx == -1 == 0xffff means: take any free slot */
            if (~snd_cards_lock & idx & 1<<idx2) {
                if (!slots[idx2] || !*slots[idx2]) {
                    idx = idx2;
                    break;
                }
            }
    }
    if (idx < 0)
        err = -ENODEV;
    else if (idx < snd_ecards_limit) {
        if (snd_cards_lock & (1 << idx))
            err = -EBUSY;   /* invalid */
    } else if (idx >= SNDRV_CARDS)
        err = -ENODEV;
    if (err < 0) {
        mutex_unlock(&snd_card_mutex);
        snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
             idx, snd_ecards_limit - 1, err);
        goto __error;
    }
    snd_cards_lock |= 1 << idx;     /* lock it */
    if (idx >= snd_ecards_limit)
        snd_ecards_limit = idx + 1; /* increase the limit */
    mutex_unlock(&snd_card_mutex);
    card->number = idx;
    card->module = module;
    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);
    init_waitqueue_head(&card->shutdown_sleep);
    atomic_set(&card->refcount, 0);
#ifdef CONFIG_PM
    mutex_init(&card->power_lock);
    init_waitqueue_head(&card->power_sleep);
#endif
    /* 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) {
        snd_printk(KERN_ERR "unable to register control minors\n");
        goto __error;
    }
    err = snd_info_card_create(card);
    if (err < 0) {
        snd_printk(KERN_ERR "unable to create card info\n");
        goto __error_ctl;
    }
    if (extra_size > 0)
        card->private_data = (char *)card + sizeof(struct snd_card);
    *card_ret = card;
    return 0;

      __error_ctl:
    snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
      __error:
    kfree(card);
    return err;
}
EXPORT_SYMBOL(snd_card_create);

/* return non-zero if a card is already locked */
int snd_card_locked(int card)
{
    int locked;

    mutex_lock(&snd_card_mutex);
    locked = snd_cards_lock & (1 << card);
    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
};

int snd_card_disconnect(struct snd_card *card)
{
    struct snd_monitor_file *mfile;
    int err;

    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;
    snd_cards_lock &= ~(1 << card->number);
    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 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_DISCONNECT);
#endif

    /* notify all devices that we are disconnected */
    err = snd_device_disconnect_all(card);
    if (err < 0)
        snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);

    snd_info_card_disconnect(card);
    if (card->card_dev) {
        device_unregister(card->card_dev);
        card->card_dev = NULL;
    }
#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 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_FREE);
#endif
    if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
        snd_printk(KERN_ERR "unable to free all devices (pre)\n");
        /* Fatal, but this situation should never occur */
    }
    if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
        snd_printk(KERN_ERR "unable to free all devices (normal)\n");
        /* Fatal, but this situation should never occur */
    }
    if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
        snd_printk(KERN_ERR "unable to free all devices (post)\n");
        /* Fatal, but this situation should never occur */
    }
    if (card->private_free)
        card->private_free(card);
    snd_info_free_entry(card->proc_id);
    if (snd_info_card_free(card) < 0) {
        snd_printk(KERN_WARNING "unable to free card info\n");
        /* Not fatal error */
    }
    kfree(card);
    return 0;
}

void snd_card_unref(struct snd_card *card)
{
    if (atomic_dec_and_test(&card->refcount)) {
        wake_up(&card->shutdown_sleep);
        if (card->free_on_last_close)
            snd_card_do_free(card);
    }
}
EXPORT_SYMBOL(snd_card_unref);

int snd_card_free_when_closed(struct snd_card *card)
{
    int ret;

    atomic_inc(&card->refcount);
    ret = snd_card_disconnect(card);
    if (ret) {
        atomic_dec(&card->refcount);
        return ret;
    }

    card->free_on_last_close = 1;
    if (atomic_dec_and_test(&card->refcount))
        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_disconnect(card);
    if (ret)
        return ret;

    /* wait, until all devices are ready for the free operation */
    wait_event(card->shutdown_sleep, !atomic_read(&card->refcount));
    snd_card_do_free(card);
    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 with_suffix;
    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;
    }

    with_suffix = false;
    for (loops = 0; loops < SNDRV_CARDS; loops++) {
        if (card_id_ok(card, id))
            return; /* OK */

        len = strlen(id);
        if (!with_suffix) {
            /* add the "_X" suffix */
            char *spos = id + len;
            if (len >  sizeof(card->id) - 3)
                spos = id + sizeof(card->id) - 3;
            strcpy(spos, "_1");
            with_suffix = true;
        } else {
            /* modify the existing suffix */
            if (id[len - 1] != '9')
                id[len - 1]++;
            else
                id[len - 1] = 'A';
        }
    }
    /* fallback to the default id */
    if (!is_default) {
        *id = 0;
        goto again;
    }
    /* last resort... */
    snd_printk(KERN_ERR "unable to set card id (%s)\n", id);
    if (card->proc_root->name)
        strcpy(card->id, card->proc_root->name);
}

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 = dev_get_drvdata(dev);
    return snprintf(buf, PAGE_SIZE, "%s\n", card ? card->id : "(null)");
}

static ssize_t
card_id_store_attr(struct device *dev, struct device_attribute *attr,
           const char *buf, size_t count)
{
    struct snd_card *card = dev_get_drvdata(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 struct device_attribute card_id_attrs =
    __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 = dev_get_drvdata(dev);
    return snprintf(buf, PAGE_SIZE, "%i\n", card ? card->number : -1);
}

static struct device_attribute card_number_attrs =
    __ATTR(number, S_IRUGO, card_number_show_attr, NULL);

int snd_card_register(struct snd_card *card)
{
    int err;

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

    if (!card->card_dev) {
        card->card_dev = device_create(sound_class, card->dev,
                           MKDEV(0, 0), card,
                           "card%i", card->number);
        if (IS_ERR(card->card_dev))
            card->card_dev = NULL;
    }

    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 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
    if (card->card_dev) {
        err = device_create_file(card->card_dev, &card_id_attrs);
        if (err < 0)
            return err;
        err = device_create_file(card->card_dev, &card_number_attrs);
        if (err < 0)
            return err;
    }

    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 */

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);

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);
    atomic_inc(&card->refcount);
    spin_unlock(&card->files_lock);
    return 0;
}

EXPORT_SYMBOL(snd_card_file_add);

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) {
        snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
        return -ENOENT;
    }
    kfree(found);
    snd_card_unref(card);
    return 0;
}

EXPORT_SYMBOL(snd_card_file_remove);

#ifdef CONFIG_PM

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 */