linux/sound/core/sound.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

412 lines
9.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Advanced Linux Sound Architecture
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*/
#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);
struct snd_card *ref = snd_card_ref(card);
if (!ref)
snd_request_card(card);
else
snd_card_unref(ref);
} 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_SND_PROC_FS
/*
* INFO PART
*/
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)
return -ENOMEM;
entry->c.text.read = snd_minor_info_read;
return snd_info_register(entry); /* freed in error path */
}
#endif /* CONFIG_SND_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;
}
#ifndef MODULE
pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
#endif
return 0;
}
static void __exit alsa_sound_exit(void)
{
snd_info_done();
unregister_chrdev(major, "alsa");
}
subsys_initcall(alsa_sound_init);
module_exit(alsa_sound_exit);