diff options
Diffstat (limited to 'sound/core/sound.c')
-rw-r--r-- | sound/core/sound.c | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/sound/core/sound.c b/sound/core/sound.c new file mode 100644 index 000000000..5fc93d005 --- /dev/null +++ b/sound/core/sound.c @@ -0,0 +1,441 @@ +/* + * 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); |