- 根目录:
- sound
- core
- device.c
/*
* Device management routines
* 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/slab.h>
#include <linux/time.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <sound/core.h>
/**
* snd_device_new - create an ALSA device component
* @card: the card instance
* @type: the device type, SNDRV_DEV_XXX
* @device_data: the data pointer of this device
* @ops: the operator table
*
* Creates a new device component for the given data pointer.
* The device will be assigned to the card and managed together
* by the card.
*
* The data pointer plays a role as the identifier, too, so the
* pointer address must be unique and unchanged.
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_device_new(struct snd_card *card, enum snd_device_type type,
void *device_data, struct snd_device_ops *ops)
{
struct snd_device *dev;
struct list_head *p;
if (snd_BUG_ON(!card || !device_data || !ops))
return -ENXIO;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
INIT_LIST_HEAD(&dev->list);
dev->card = card;
dev->type = type;
dev->state = SNDRV_DEV_BUILD;
dev->device_data = device_data;
dev->ops = ops;
/* insert the entry in an incrementally sorted list */
list_for_each_prev(p, &card->devices) {
struct snd_device *pdev = list_entry(p, struct snd_device, list);
if ((unsigned int)pdev->type <= (unsigned int)type)
break;
}
list_add(&dev->list, p);
return 0;
}
EXPORT_SYMBOL(snd_device_new);
static void __snd_device_disconnect(struct snd_device *dev)
{
if (dev->state == SNDRV_DEV_REGISTERED) {
if (dev->ops->dev_disconnect &&
dev->ops->dev_disconnect(dev))
dev_err(dev->card->dev, "device disconnect failure\n");
dev->state = SNDRV_DEV_DISCONNECTED;
}
}
static void __snd_device_free(struct snd_device *dev)
{
/* unlink */
list_del(&dev->list);
__snd_device_disconnect(dev);
if (dev->ops->dev_free) {
if (dev->ops->dev_free(dev))
dev_err(dev->card->dev, "device free failure\n");
}
kfree(dev);
}
static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
{
struct snd_device *dev;
list_for_each_entry(dev, &card->devices, list)
if (dev->device_data == device_data)
return dev;
return NULL;
}
/**
* snd_device_disconnect - disconnect the device
* @card: the card instance
* @device_data: the data pointer to disconnect
*
* Turns the device into the disconnection state, invoking
* dev_disconnect callback, if the device was already registered.
*
* Usually called from snd_card_disconnect().
*
* Return: Zero if successful, or a negative error code on failure or if the
* device not found.
*/
void snd_device_disconnect(struct snd_card *card, void *device_data)
{
struct snd_device *dev;
if (snd_BUG_ON(!card || !device_data))
return;
dev = look_for_dev(card, device_data);
if (dev)
__snd_device_disconnect(dev);
else
dev_dbg(card->dev, "device disconnect %p (from %pF), not found\n",
device_data, __builtin_return_address(0));
}
EXPORT_SYMBOL_GPL(snd_device_disconnect);
/**
* snd_device_free - release the device from the card
* @card: the card instance
* @device_data: the data pointer to release
*
* Removes the device from the list on the card and invokes the
* callbacks, dev_disconnect and dev_free, corresponding to the state.
* Then release the device.
*/
void snd_device_free(struct snd_card *card, void *device_data)
{
struct snd_device *dev;
if (snd_BUG_ON(!card || !device_data))
return;
dev = look_for_dev(card, device_data);
if (dev)
__snd_device_free(dev);
else
dev_dbg(card->dev, "device free %p (from %pF), not found\n",
device_data, __builtin_return_address(0));
}
EXPORT_SYMBOL(snd_device_free);
static int __snd_device_register(struct snd_device *dev)
{
if (dev->state == SNDRV_DEV_BUILD) {
if (dev->ops->dev_register) {
int err = dev->ops->dev_register(dev);
if (err < 0)
return err;
}
dev->state = SNDRV_DEV_REGISTERED;
}
return 0;
}
/**
* snd_device_register - register the device
* @card: the card instance
* @device_data: the data pointer to register
*
* Registers the device which was already created via
* snd_device_new(). Usually this is called from snd_card_register(),
* but it can be called later if any new devices are created after
* invocation of snd_card_register().
*
* Return: Zero if successful, or a negative error code on failure or if the
* device not found.
*/
int snd_device_register(struct snd_card *card, void *device_data)
{
struct snd_device *dev;
if (snd_BUG_ON(!card || !device_data))
return -ENXIO;
dev = look_for_dev(card, device_data);
if (dev)
return __snd_device_register(dev);
snd_BUG();
return -ENXIO;
}
EXPORT_SYMBOL(snd_device_register);
/*
* register all the devices on the card.
* called from init.c
*/
int snd_device_register_all(struct snd_card *card)
{
struct snd_device *dev;
int err;
if (snd_BUG_ON(!card))
return -ENXIO;
list_for_each_entry(dev, &card->devices, list) {
err = __snd_device_register(dev);
if (err < 0)
return err;
}
return 0;
}
/*
* disconnect all the devices on the card.
* called from init.c
*/
void snd_device_disconnect_all(struct snd_card *card)
{
struct snd_device *dev;
if (snd_BUG_ON(!card))
return;
list_for_each_entry_reverse(dev, &card->devices, list)
__snd_device_disconnect(dev);
}
/*
* release all the devices on the card.
* called from init.c
*/
void snd_device_free_all(struct snd_card *card)
{
struct snd_device *dev, *next;
if (snd_BUG_ON(!card))
return;
list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
__snd_device_free(dev);
}