- 根目录:
- sound
- core
- sound.c
/*
* Advanced Linux Sound Architecture
* 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/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 <perex@perex.cz>");
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
/**
* snd_request_card - try to load the card module
* @card: the card number
*
* Tries to load the module "snd-card-X" for the given card number
* via request_module. Returns immediately if already loaded.
*/
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 */
/**
* snd_lookup_minor_data - get user data of a registered device
* @minor: the minor number
* @type: device type (SNDRV_DEVICE_TYPE_XXX)
*
* Checks that a minor device with the specified type is registered, and returns
* its user data pointer.
*
* This function increments the reference counter of the card instance
* if an associated instance with the given minor number and type is found.
* The caller must call snd_card_unref() appropriately later.
*
* Return: The user data pointer if the specified device is found. %NULL
* otherwise.
*/
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)
get_device(&mreg->card_ptr->card_dev);
} 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 *new_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;
}
}
new_fops = fops_get(mptr->f_ops);
mutex_unlock(&sound_mutex);
if (!new_fops)
return -ENODEV;
replace_fops(file, new_fops);
if (file->f_op->open)
err = file->f_op->open(inode, file);
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, struct snd_card *card, int dev)
{
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_find_free_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;
if (snd_minors[minor])
return -EBUSY;
return minor;
}
#endif
/**
* snd_register_device - Register the ALSA device file for the card
* @type: the device type, SNDRV_DEVICE_TYPE_XXX
* @card: the card instance
* @dev: the device index
* @f_ops: the file operations
* @private_data: user pointer for f_ops->open()
* @device: the device to register
*
* Registers an ALSA device file for the given card.
* The operators have to be set in reg parameter.
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_register_device(int type, struct snd_card *card, int dev,
const struct file_operations *f_ops,
void *private_data, struct device *device)
{
int minor;
int err = 0;
struct snd_minor *preg;
if (snd_BUG_ON(!device))
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);
minor = snd_find_free_minor(type, card, dev);
if (minor < 0) {
err = minor;
goto error;
}
preg->dev = device;
device->devt = MKDEV(major, minor);
err = device_add(device);
if (err < 0)
goto error;
snd_minors[minor] = preg;
error:
mutex_unlock(&sound_mutex);
if (err < 0)
kfree(preg);
return err;
}
EXPORT_SYMBOL(snd_register_device);
/**
* snd_unregister_device - unregister the device on the given card
* @dev: the device instance
*
* Unregisters the device file already registered via
* snd_register_device().
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_unregister_device(struct device *dev)
{
int minor;
struct snd_minor *preg;
mutex_lock(&sound_mutex);
for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
preg = snd_minors[minor];
if (preg && preg->dev == dev) {
snd_minors[minor] = NULL;
device_del(dev);
kfree(preg);
break;
}
}
mutex_unlock(&sound_mutex);
if (minor >= ARRAY_SIZE(snd_minors))
return -ENOENT;
return 0;
}
EXPORT_SYMBOL(snd_unregister_device);
#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)) {
pr_err("ALSA core: 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
pr_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);