path: root/sound/core/pcm.c

/*
 *  Digital Audio (PCM) abstract layer
 *  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/mutex.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/pcm.h>
#include <sound/control.h>
#include <sound/info.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Abramo Bagnara <abramo@alsa-project.org>");
MODULE_DESCRIPTION("Midlevel PCM code for ALSA.");
MODULE_LICENSE("GPL");

static LIST_HEAD(snd_pcm_devices);
static LIST_HEAD(snd_pcm_notify_list);
static DEFINE_MUTEX(register_mutex);

static int snd_pcm_free(struct snd_pcm *pcm);
static int snd_pcm_dev_free(struct snd_device *device);
static int snd_pcm_dev_register(struct snd_device *device);
static int snd_pcm_dev_disconnect(struct snd_device *device);

static struct snd_pcm *snd_pcm_get(struct snd_card *card, int device)
{
	struct snd_pcm *pcm;

	list_for_each_entry(pcm, &snd_pcm_devices, list) {
		if (pcm->card == card && pcm->device == device)
			return pcm;
	}
	return NULL;
}

static int snd_pcm_next(struct snd_card *card, int device)
{
	struct snd_pcm *pcm;

	list_for_each_entry(pcm, &snd_pcm_devices, list) {
		if (pcm->card == card && pcm->device > device)
			return pcm->device;
		else if (pcm->card->number > card->number)
			return -1;
	}
	return -1;
}

static int snd_pcm_add(struct snd_pcm *newpcm)
{
	struct snd_pcm *pcm;

	list_for_each_entry(pcm, &snd_pcm_devices, list) {
		if (pcm->card == newpcm->card && pcm->device == newpcm->device)
			return -EBUSY;
		if (pcm->card->number > newpcm->card->number ||
				(pcm->card == newpcm->card &&
				pcm->device > newpcm->device)) {
			list_add(&newpcm->list, pcm->list.prev);
			return 0;
		}
	}
	list_add_tail(&newpcm->list, &snd_pcm_devices);
	return 0;
}

static int snd_pcm_control_ioctl(struct snd_card *card,
				 struct snd_ctl_file *control,
				 unsigned int cmd, unsigned long arg)
{
	switch (cmd) {
	case SNDRV_CTL_IOCTL_PCM_NEXT_DEVICE:
		{
			int device;

			if (get_user(device, (int __user *)arg))
				return -EFAULT;
			mutex_lock(&register_mutex);
			device = snd_pcm_next(card, device);
			mutex_unlock(&register_mutex);
			if (put_user(device, (int __user *)arg))
				return -EFAULT;
			return 0;
		}
	case SNDRV_CTL_IOCTL_PCM_INFO:
		{
			struct snd_pcm_info __user *info;
			unsigned int device, subdevice;
			int stream;
			struct