sound.c

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/*
 *  Advanced Linux Sound Architecture
 *  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/slab.h>
#include <linux/time.h>
#include <linux/device.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <sound/control.h>
#include <sound/initval.h>
#include <linux/kmod.h>
#include <linux/mutex.h>

static int major = CONFIG_SND_MAJOR;
int snd_major;
EXPORT_SYMBOL(snd_major);

static int cards_limit = 1;

MODULE_AUTHOR("Jaroslav Kysela <[email protected]>");
MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
MODULE_LICENSE("GPL");
module_param(major, int, 0444);
MODULE_PARM_DESC(major, "Major # for sound driver.");
module_param(cards_limit, int, 0444);
MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);

/* this one holds the actual max. card number currently available.
 * as default, it's identical with cards_limit option.  when more
 * modules are loaded manually, this limit number increases, too.
 */
int snd_ecards_limit;
EXPORT_SYMBOL(snd_ecards_limit);

static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
static DEFINE_MUTEX(sound_mutex);

#ifdef CONFIG_MODULES

void snd_request_card(int card)
{
    if (snd_card_locked(card))
        return;
    if (card < 0 || card >= cards_limit)
        return;
    request_module("snd-card-%i", card);
}

EXPORT_SYMBOL(snd_request_card);

static void snd_request_other(int minor)
{
    char *str;

    switch (minor) {
    case SNDRV_MINOR_SEQUENCER: str = "snd-seq";    break;
    case SNDRV_MINOR_TIMER:     str = "snd-timer";  break;
    default:            return;
    }
    request_module(str);
}

#endif  /* modular kernel */

void *snd_lookup_minor_data(unsigned int minor, int type)
{
    struct snd_minor *mreg;
    void *private_data;

    if (minor >= ARRAY_SIZE(snd_minors))
        return NULL;
    mutex_lock(&sound_mutex);
    mreg = snd_minors[minor];
    if (mreg && mreg->type == type) {
        private_data = mreg->private_data;
        if (private_data && mreg->card_ptr)
            atomic_inc(&mreg->card_ptr->refcount);
    } else
        private_data = NULL;
    mutex_unlock(&sound_mutex);
    return private_data;
}

EXPORT_SYMBOL(snd_lookup_minor_data);

#ifdef CONFIG_MODULES
static struct snd_minor *autoload_device(unsigned int minor)
{
    int dev;
    mutex_unlock(&sound_mutex); /* release lock temporarily */
    dev = SNDRV_MINOR_DEVICE(minor);
    if (dev == SNDRV_MINOR_CONTROL) {
        /* /dev/aloadC? */
        int card = SNDRV_MINOR_CARD(minor);
        if (snd_cards[card] == NULL)
            snd_request_card(card);
    } else if (dev == SNDRV_MINOR_GLOBAL) {
        /* /dev/aloadSEQ */
        snd_request_other(minor);
    }
    mutex_lock(&sound_mutex); /* reacuire lock */
    return snd_minors[minor];
}
#else /* !CONFIG_MODULES */
#define autoload_device(minor)  NULL
#endif /* CONFIG_MODULES */

static int snd_open(struct inode *inode, struct file *file)
{
    unsigned int minor = iminor(inode);
    struct snd_minor *mptr = NULL;
    const struct file_operations *old_fops;
    int err = 0;

    if (minor >= ARRAY_SIZE(snd_minors))
        return -ENODEV;
    mutex_lock(&sound_mutex);
    mptr = snd_minors[minor];
    if (mptr == NULL) {
        mptr = autoload_device(minor);
        if (!mptr) {
            mutex_unlock(&sound_mutex);
            return -ENODEV;
        }
    }
    old_fops = file->f_op;
    file->f_op = fops_get(mptr->f_ops);
    if (file->f_op == NULL) {
        file->f_op = old_fops;
        err = -ENODEV;
    }
    mutex_unlock(&sound_mutex);
    if (err < 0)
        return err;

    if (file->f_op->open) {
        err = file->f_op->open(inode, file);
        if (err) {
            fops_put(file->f_op);
            file->f_op = fops_get(old_fops);
        }
    }
    fops_put(old_fops);
    return err;
}

static const struct file_operations snd_fops =
{
    .owner =    THIS_MODULE,
    .open =     snd_open,
    .llseek =   noop_llseek,
};

#ifdef CONFIG_SND_DYNAMIC_MINORS
static int snd_find_free_minor(int type)
{
    int minor;

    /* static minors for module auto loading */
    if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
        return SNDRV_MINOR_SEQUENCER;
    if (type == SNDRV_DEVICE_TYPE_TIMER)
        return SNDRV_MINOR_TIMER;

    for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
        /* skip static minors still used for module auto loading */
        if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
            continue;
        if (minor == SNDRV_MINOR_SEQUENCER ||
            minor == SNDRV_MINOR_TIMER)
            continue;
        if (!snd_minors[minor])
            return minor;
    }
    return -EBUSY;
}
#else
static int snd_kernel_minor(int type, struct snd_card *card, int dev)
{
    int minor;

    switch (type) {
    case SNDRV_DEVICE_TYPE_SEQUENCER:
    case SNDRV_DEVICE_TYPE_TIMER:
        minor = type;
        break;
    case SNDRV_DEVICE_TYPE_CONTROL:
        if (snd_BUG_ON(!card))
            return -EINVAL;
        minor = SNDRV_MINOR(card->number, type);
        break;
    case SNDRV_DEVICE_TYPE_HWDEP:
    case SNDRV_DEVICE_TYPE_RAWMIDI:
    case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
    case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
    case SNDRV_DEVICE_TYPE_COMPRESS:
        if (snd_BUG_ON(!card))
            return -EINVAL;
        minor = SNDRV_MINOR(card->number, type + dev);
        break;
    default:
        return -EINVAL;
    }
    if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
        return -EINVAL;
    return minor;
}
#endif

int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
                const struct file_operations *f_ops,
                void *private_data,
                const char *name, struct device *device)
{
    int minor;
    struct snd_minor *preg;

    if (snd_BUG_ON(!name))
        return -EINVAL;
    preg = kmalloc(sizeof *preg, GFP_KERNEL);
    if (preg == NULL)
        return -ENOMEM;
    preg->type = type;
    preg->card = card ? card->number : -1;
    preg->device = dev;
    preg->f_ops = f_ops;
    preg->private_data = private_data;
    preg->card_ptr = card;
    mutex_lock(&sound_mutex);
#ifdef CONFIG_SND_DYNAMIC_MINORS
    minor = snd_find_free_minor(type);
#else
    minor = snd_kernel_minor(type, card, dev);
    if (minor >= 0 && snd_minors[minor])
        minor = -EBUSY;
#endif
    if (minor < 0) {
        mutex_unlock(&sound_mutex);
        kfree(preg);
        return minor;
    }
    snd_minors[minor] = preg;
    preg->dev = device_create(sound_class, device, MKDEV(major, minor),
                  private_data, "%s", name);
    if (IS_ERR(preg->dev)) {
        snd_minors[minor] = NULL;
        mutex_unlock(&sound_mutex);
        minor = PTR_ERR(preg->dev);
        kfree(preg);
        return minor;
    }

    mutex_unlock(&sound_mutex);
    return 0;
}

EXPORT_SYMBOL(snd_register_device_for_dev);

/* find the matching minor record
 * return the index of snd_minor, or -1 if not found
 */
static int find_snd_minor(int type, struct snd_card *card, int dev)
{
    int cardnum, minor;
    struct snd_minor *mptr;

    cardnum = card ? card->number : -1;
    for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
        if ((mptr = snd_minors[minor]) != NULL &&
            mptr->type == type &&
            mptr->card == cardnum &&
            mptr->device == dev)
            return minor;
    return -1;
}

int snd_unregister_device(int type, struct snd_card *card, int dev)
{
    int minor;

    mutex_lock(&sound_mutex);
    minor = find_snd_minor(type, card, dev);
    if (minor < 0) {
        mutex_unlock(&sound_mutex);
        return -EINVAL;
    }

    device_destroy(sound_class, MKDEV(major, minor));

    kfree(snd_minors[minor]);
    snd_minors[minor] = NULL;
    mutex_unlock(&sound_mutex);
    return 0;
}

EXPORT_SYMBOL(snd_unregister_device);

int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
                  struct device_attribute *attr)
{
    int minor, ret = -EINVAL;
    struct device *d;

    mutex_lock(&sound_mutex);
    minor = find_snd_minor(type, card, dev);
    if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
        ret = device_create_file(d, attr);
    mutex_unlock(&sound_mutex);
    return ret;

}

EXPORT_SYMBOL(snd_add_device_sysfs_file);

#ifdef CONFIG_PROC_FS
/*
 *  INFO PART
 */

static struct snd_info_entry *snd_minor_info_entry;

static const char *snd_device_type_name(int type)
{
    switch (type) {
    case SNDRV_DEVICE_TYPE_CONTROL:
        return "control";
    case SNDRV_DEVICE_TYPE_HWDEP:
        return "hardware dependent";
    case SNDRV_DEVICE_TYPE_RAWMIDI:
        return "raw midi";
    case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
        return "digital audio playback";
    case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
        return "digital audio capture";
    case SNDRV_DEVICE_TYPE_SEQUENCER:
        return "sequencer";
    case SNDRV_DEVICE_TYPE_TIMER:
        return "timer";
    default:
        return "?";
    }
}

static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
    int minor;
    struct snd_minor *mptr;

    mutex_lock(&sound_mutex);
    for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
        if (!(mptr = snd_minors[minor]))
            continue;
        if (mptr->card >= 0) {
            if (mptr->device >= 0)
                snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
                        minor, mptr->card, mptr->device,
                        snd_device_type_name(mptr->type));
            else
                snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
                        minor, mptr->card,
                        snd_device_type_name(mptr->type));
        } else
            snd_iprintf(buffer, "%3i:        : %s\n", minor,
                    snd_device_type_name(mptr->type));
    }
    mutex_unlock(&sound_mutex);
}

int __init snd_minor_info_init(void)
{
    struct snd_info_entry *entry;

    entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
    if (entry) {
        entry->c.text.read = snd_minor_info_read;
        if (snd_info_register(entry) < 0) {
            snd_info_free_entry(entry);
            entry = NULL;
        }
    }
    snd_minor_info_entry = entry;
    return 0;
}

int __exit snd_minor_info_done(void)
{
    snd_info_free_entry(snd_minor_info_entry);
    return 0;
}
#endif /* CONFIG_PROC_FS */

/*
 *  INIT PART
 */

static int __init alsa_sound_init(void)
{
    snd_major = major;
    snd_ecards_limit = cards_limit;
    if (register_chrdev(major, "alsa", &snd_fops)) {
        snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
        return -EIO;
    }
    if (snd_info_init() < 0) {
        unregister_chrdev(major, "alsa");
        return -ENOMEM;
    }
    snd_info_minor_register();
#ifndef MODULE
    printk(KERN_INFO "Advanced Linux Sound Architecture Driver Initialized.\n");
#endif
    return 0;
}

static void __exit alsa_sound_exit(void)
{
    snd_info_minor_unregister();
    snd_info_done();
    unregister_chrdev(major, "alsa");
}

subsys_initcall(alsa_sound_init);
module_exit(alsa_sound_exit);