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Commit b21c60a4 authored by Vinod Koul's avatar Vinod Koul Committed by Takashi Iwai
Browse files

ALSA: core: add support for compress_offload 



This patch adds core.c, the file which implements the ioctls and
registers the devices

Signed-off-by: default avatarVinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent e60061a3

sound/core/compress_offload.c

0 → 100644
+765 −0
Original line number Diff line number Diff line 
/*

 *  compress_core.c - compress offload core

 *

 *  Copyright (C) 2011 Intel Corporation

 *  Authors:	Vinod Koul <vinod.koul@linux.intel.com>

 *		Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 *

 *  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; version 2 of the License.

 *

 *  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.

 *

 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 *

 */

#define FORMAT(fmt) "%s: %d: " fmt, __func__, __LINE__

#define pr_fmt(fmt) KBUILD_MODNAME ": " FORMAT(fmt)



#include <linux/file.h>

#include <linux/fs.h>

#include <linux/list.h>

#include <linux/mm.h>

#include <linux/mutex.h>

#include <linux/poll.h>

#include <linux/slab.h>

#include <linux/sched.h>

#include <linux/uio.h>

#include <linux/uaccess.h>

#include <linux/module.h>

#include <sound/core.h>

#include <sound/initval.h>

#include <sound/compress_params.h>

#include <sound/compress_offload.h>

#include <sound/compress_driver.h>



/* TODO:

 * - add substream support for multiple devices in case of

 *	SND_DYNAMIC_MINORS is not used

 * - Multiple node representation

 *	driver should be able to register multiple nodes

 */



static DEFINE_MUTEX(device_mutex);



struct snd_compr_file {

	unsigned long caps;

	struct snd_compr_stream stream;

};



/*

 * a note on stream states used:

 * we use follwing states in the compressed core

 * SNDRV_PCM_STATE_OPEN: When stream has been opened.

 * SNDRV_PCM_STATE_SETUP: When stream has been initialized. This is done by

 *	calling SNDRV_COMPRESS_SET_PARAMS. running streams will come to this

 *	state at stop by calling SNDRV_COMPRESS_STOP, or at end of drain.

 * SNDRV_PCM_STATE_RUNNING: When stream has been started and is

 *	decoding/encoding and rendering/capturing data.

 * SNDRV_PCM_STATE_DRAINING: When stream is draining current data. This is done

 *	by calling SNDRV_COMPRESS_DRAIN.

 * SNDRV_PCM_STATE_PAUSED: When stream is paused. This is done by calling

 *	SNDRV_COMPRESS_PAUSE. It can be stopped or resumed by calling

 *	SNDRV_COMPRESS_STOP or SNDRV_COMPRESS_RESUME respectively.

 */

static int snd_compr_open(struct inode *inode, struct file *f)

{

	struct snd_compr *compr;

	struct snd_compr_file *data;

	struct snd_compr_runtime *runtime;

	enum snd_compr_direction dirn;

	int maj = imajor(inode);

	int ret;



	if (f->f_flags & O_WRONLY)

		dirn = SND_COMPRESS_PLAYBACK;

	else if (f->f_flags & O_RDONLY)

		dirn = SND_COMPRESS_CAPTURE;

	else {

		pr_err("invalid direction\n");

		return -EINVAL;

	}



	if (maj == snd_major)

		compr = snd_lookup_minor_data(iminor(inode),

					SNDRV_DEVICE_TYPE_COMPRESS);

	else

		return -EBADFD;



	if (compr == NULL) {

		pr_err("no device data!!!\n");

		return -ENODEV;

	}



	if (dirn != compr->direction) {

		pr_err("this device doesn't support this direction\n");

		return -EINVAL;

	}



	data = kzalloc(sizeof(*data), GFP_KERNEL);

	if (!data)

		return -ENOMEM;

	data->stream.ops = compr->ops;

	data->stream.direction = dirn;

	data->stream.private_data = compr->private_data;

	data->stream.device = compr;

	runtime = kzalloc(sizeof(*runtime), GFP_KERNEL);

	if (!runtime) {

		kfree(data);

		return -ENOMEM;

	}

	runtime->state = SNDRV_PCM_STATE_OPEN;

	init_waitqueue_head(&runtime->sleep);

	data->stream.runtime = runtime;

	f->private_data = (void *)data;

	mutex_lock(&compr->lock);

	ret = compr->ops->open(&data->stream);

	mutex_unlock(&compr->lock);

	if (ret) {

		kfree(runtime);

		kfree(data);

	}

	return ret;

}



static int snd_compr_free(struct inode *inode, struct file *f)

{

	struct snd_compr_file *data = f->private_data;

	data->stream.ops->free(&data->stream);

	kfree(data->stream.runtime->buffer);

	kfree(data->stream.runtime);

	kfree(data);

	return 0;

}



static void snd_compr_update_tstamp(struct snd_compr_stream *stream,

		struct snd_compr_tstamp *tstamp)

{

	if (!stream->ops->pointer)

		return;

	stream->ops->pointer(stream, tstamp);

	pr_debug("dsp consumed till %d total %d bytes\n",

		tstamp->byte_offset, tstamp->copied_total);

	stream->runtime->hw_pointer = tstamp->byte_offset;

	stream->runtime->total_bytes_transferred = tstamp->copied_total;

}



static size_t snd_compr_calc_avail(struct snd_compr_stream *stream,

		struct snd_compr_avail *avail)

{

	long avail_calc; /*this needs to be signed variable */



	snd_compr_update_tstamp(stream, &avail->tstamp);



	/* FIXME: This needs to be different for capture stream,

	   available is # of compressed data, for playback it's

	   remainder of buffer */



	if (stream->runtime->total_bytes_available == 0 &&

			stream->runtime->state == SNDRV_PCM_STATE_SETUP) {

		pr_debug("detected init and someone forgot to do a write\n");

		return stream->runtime->buffer_size;

	}

	pr_debug("app wrote %lld, DSP consumed %lld\n",

			stream->runtime->total_bytes_available,

			stream->runtime->total_bytes_transferred);

	if (stream->runtime->total_bytes_available ==

				stream->runtime->total_bytes_transferred) {

		pr_debug("both pointers are same, returning full avail\n");

		return stream->runtime->buffer_size;

	}



	/* FIXME: this routine isn't consistent, in one test we use

	 * cumulative values and in the other byte offsets. Do we

	 * really need the byte offsets if the cumulative values have

	 * been updated? In the PCM interface app_ptr and hw_ptr are

	 * already cumulative */



	avail_calc = stream->runtime->buffer_size -

		(stream->runtime->app_pointer - stream->runtime->hw_pointer);

	pr_debug("calc avail as %ld, app_ptr %lld, hw+ptr %lld\n", avail_calc,

			stream->runtime->app_pointer,

			stream->runtime->hw_pointer);

	if (avail_calc >= stream->runtime->buffer_size)

		avail_calc -= stream->runtime->buffer_size;

	pr_debug("ret avail as %ld\n", avail_calc);

	avail->avail = avail_calc;

	return avail_calc;

}



static inline size_t snd_compr_get_avail(struct snd_compr_stream *stream)

{

	struct snd_compr_avail avail;



	return snd_compr_calc_avail(stream, &avail);

}



static int

snd_compr_ioctl_avail(struct snd_compr_stream *stream, unsigned long arg)

{

	struct snd_compr_avail ioctl_avail;

	size_t avail;



	avail = snd_compr_calc_avail(stream, &ioctl_avail);

	ioctl_avail.avail = avail;



	if (copy_to_user((__u64 __user *)arg,

				&ioctl_avail, sizeof(ioctl_avail)))

		return -EFAULT;

	return 0;

}



static int snd_compr_write_data(struct snd_compr_stream *stream,

	       const char __user *buf, size_t count)

{

	void *dstn;

	size_t copy;

	struct snd_compr_runtime *runtime = stream->runtime;



	dstn = runtime->buffer + runtime->app_pointer;

	pr_debug("copying %ld at %lld\n",

			(unsigned long)count, runtime->app_pointer);

	if (count < runtime->buffer_size - runtime->app_pointer) {

		if (copy_from_user(dstn, buf, count))

			return -EFAULT;

		runtime->app_pointer += count;

	} else {

		copy = runtime->buffer_size - runtime->app_pointer;

		if (copy_from_user(dstn, buf, copy))

			return -EFAULT;

		if (copy_from_user(runtime->buffer, buf + copy, count - copy))

			return -EFAULT;

		runtime->app_pointer = count - copy;

	}

	/* if DSP cares, let it know data has been written */

	if (stream->ops->ack)

		stream->ops->ack(stream, count);

	return count;

}



static ssize_t snd_compr_write(struct file *f, const char __user *buf,

		size_t count, loff_t *offset)

{

	struct snd_compr_file *data = f->private_data;

	struct snd_compr_stream *stream;

	size_t avail;

	int retval;



	if (snd_BUG_ON(!data))

		return -EFAULT;



	stream = &data->stream;

	mutex_lock(&stream->device->lock);

	/* write is allowed when stream is running or has been steup */

	if (stream->runtime->state != SNDRV_PCM_STATE_SETUP &&

			stream->runtime->state != SNDRV_PCM_STATE_RUNNING) {

		mutex_unlock(&stream->device->lock);

		return -EBADFD;

	}



	avail = snd_compr_get_avail(stream);

	pr_debug("avail returned %ld\n", (unsigned long)avail);

	/* calculate how much we can write to buffer */

	if (avail > count)

		avail = count;



	if (stream->ops->copy)

		retval = stream->ops->copy(stream, buf, avail);

	else

		retval = snd_compr_write_data(stream, buf, avail);

	if (retval > 0)

		stream->runtime->total_bytes_available += retval;



	/* while initiating the stream, write should be called before START

	 * call, so in setup move state */

	if (stream->runtime->state == SNDRV_PCM_STATE_SETUP) {

		stream->runtime->state = SNDRV_PCM_STATE_PREPARED;

		pr_debug("stream prepared, Houston we are good to go\n");

	}



	mutex_unlock(&stream->device->lock);

	return retval;

}





static ssize_t snd_compr_read(struct file *f, char __user *buf,

		size_t count, loff_t *offset)

{

	return -ENXIO;

}



static int snd_compr_mmap(struct file *f, struct vm_area_struct *vma)

{

	return -ENXIO;

}



static inline int snd_compr_get_poll(struct snd_compr_stream *stream)

{

	if (stream->direction == SND_COMPRESS_PLAYBACK)

		return POLLOUT | POLLWRNORM;

	else

		return POLLIN | POLLRDNORM;

}



static unsigned int snd_compr_poll(struct file *f, poll_table *wait)

{

	struct snd_compr_file *data = f->private_data;

	struct snd_compr_stream *stream;

	size_t avail;

	int retval = 0;



	if (snd_BUG_ON(!data))

		return -EFAULT;

	stream = &data->stream;

	if (snd_BUG_ON(!stream))

		return -EFAULT;



	mutex_lock(&stream->device->lock);

	if (stream->runtime->state == SNDRV_PCM_STATE_PAUSED ||

			stream->runtime->state == SNDRV_PCM_STATE_OPEN) {

		retval = -EBADFD;

		goto out;

	}

	poll_wait(f, &stream->runtime->sleep, wait);



	avail = snd_compr_get_avail(stream);

	pr_debug("avail is %ld\n", (unsigned long)avail);

	/* check if we have at least one fragment to fill */

	switch (stream->runtime->state) {

	case SNDRV_PCM_STATE_DRAINING:

		/* stream has been woken up after drain is complete

		 * draining done so set stream state to stopped

		 */

		retval = snd_compr_get_poll(stream);

		stream->runtime->state = SNDRV_PCM_STATE_SETUP;

		break;

	case SNDRV_PCM_STATE_RUNNING:

	case SNDRV_PCM_STATE_PREPARED:

	case SNDRV_PCM_STATE_PAUSED:

		if (avail >= stream->runtime->fragment_size)

			retval = snd_compr_get_poll(stream);

		break;

	default:

		if (stream->direction == SND_COMPRESS_PLAYBACK)

			retval = POLLOUT | POLLWRNORM | POLLERR;

		else

			retval = POLLIN | POLLRDNORM | POLLERR;

		break;

	}

out:

	mutex_unlock(&stream->device->lock);

	return retval;

}



static int

snd_compr_get_caps(struct snd_compr_stream *stream, unsigned long arg)

{

	int retval;

	struct snd_compr_caps caps;



	if (!stream->ops->get_caps)

		return -ENXIO;



	retval = stream->ops->get_caps(stream, &caps);

	if (retval)

		goto out;

	if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))

		retval = -EFAULT;

out:

	return retval;

}



static int

snd_compr_get_codec_caps(struct snd_compr_stream *stream, unsigned long arg)

{

	int retval;

	struct snd_compr_codec_caps *caps;



	if (!stream->ops->get_codec_caps)

		return -ENXIO;



	caps = kmalloc(sizeof(*caps), GFP_KERNEL);

	if (!caps)

		return -ENOMEM;



	retval = stream->ops->get_codec_caps(stream, caps);

	if (retval)

		goto out;

	if (copy_to_user((void __user *)arg, caps, sizeof(*caps)))

		retval = -EFAULT;



out:

	kfree(caps);

	return retval;

}



/* revisit this with snd_pcm_preallocate_xxx */

static int snd_compr_allocate_buffer(struct snd_compr_stream *stream,

		struct snd_compr_params *params)

{

	unsigned int buffer_size;

	void *buffer;



	buffer_size = params->buffer.fragment_size * params->buffer.fragments;

	if (stream->ops->copy) {

		buffer = NULL;

		/* if copy is defined the driver will be required to copy

		 * the data from core

		 */

	} else {

		buffer = kmalloc(buffer_size, GFP_KERNEL);

		if (!buffer)

			return -ENOMEM;

	}

	stream->runtime->fragment_size = params->buffer.fragment_size;

	stream->runtime->fragments = params->buffer.fragments;

	stream->runtime->buffer = buffer;

	stream->runtime->buffer_size = buffer_size;

	return 0;

}



static int

snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)

{

	struct snd_compr_params *params;

	int retval;



	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {

		/*

		 * we should allow parameter change only when stream has been

		 * opened not in other cases

		 */

		params = kmalloc(sizeof(*params), GFP_KERNEL);

		if (!params)

			return -ENOMEM;

		if (copy_from_user(params, (void __user *)arg, sizeof(*params)))

			return -EFAULT;

		retval = snd_compr_allocate_buffer(stream, params);

		if (retval) {

			kfree(params);

			return -ENOMEM;

		}

		retval = stream->ops->set_params(stream, params);

		if (retval)

			goto out;

		stream->runtime->state = SNDRV_PCM_STATE_SETUP;

	} else

		return -EPERM;

out:

	kfree(params);

	return retval;

}



static int

snd_compr_get_params(struct snd_compr_stream *stream, unsigned long arg)

{

	struct snd_codec *params;

	int retval;



	if (!stream->ops->get_params)

		return -EBADFD;



	params = kmalloc(sizeof(*params), GFP_KERNEL);

	if (!params)

		return -ENOMEM;

	retval = stream->ops->get_params(stream, params);

	if (retval)

		goto out;

	if (copy_to_user((char __user *)arg, params, sizeof(*params)))

		retval = -EFAULT;



out:

	kfree(params);

	return retval;

}



static inline int

snd_compr_tstamp(struct snd_compr_stream *stream, unsigned long arg)

{

	struct snd_compr_tstamp tstamp;



	snd_compr_update_tstamp(stream, &tstamp);

	return copy_to_user((struct snd_compr_tstamp __user *)arg,

		&tstamp, sizeof(tstamp)) ? -EFAULT : 0;

}



static int snd_compr_pause(struct snd_compr_stream *stream)

{

	int retval;



	if (stream->runtime->state != SNDRV_PCM_STATE_RUNNING)

		return -EPERM;

	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_PAUSE_PUSH);

	if (!retval) {

		stream->runtime->state = SNDRV_PCM_STATE_PAUSED;

		wake_up(&stream->runtime->sleep);

	}

	return retval;

}



static int snd_compr_resume(struct snd_compr_stream *stream)

{

	int retval;



	if (stream->runtime->state != SNDRV_PCM_STATE_PAUSED)

		return -EPERM;

	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_PAUSE_RELEASE);

	if (!retval)

		stream->runtime->state = SNDRV_PCM_STATE_RUNNING;

	return retval;

}



static int snd_compr_start(struct snd_compr_stream *stream)

{

	int retval;



	if (stream->runtime->state != SNDRV_PCM_STATE_PREPARED)

		return -EPERM;

	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_START);

	if (!retval)

		stream->runtime->state = SNDRV_PCM_STATE_RUNNING;

	return retval;

}



static int snd_compr_stop(struct snd_compr_stream *stream)

{

	int retval;



	if (stream->runtime->state == SNDRV_PCM_STATE_PREPARED ||

			stream->runtime->state == SNDRV_PCM_STATE_SETUP)

		return -EPERM;

	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_STOP);

	if (!retval) {

		stream->runtime->state = SNDRV_PCM_STATE_SETUP;

		wake_up(&stream->runtime->sleep);

	}

	return retval;

}



static int snd_compr_drain(struct snd_compr_stream *stream)

{

	int retval;



	if (stream->runtime->state == SNDRV_PCM_STATE_PREPARED ||

			stream->runtime->state == SNDRV_PCM_STATE_SETUP)

		return -EPERM;

	retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_DRAIN);

	if (!retval) {

		stream->runtime->state = SNDRV_PCM_STATE_DRAINING;

		wake_up(&stream->runtime->sleep);

	}

	return retval;

}



static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)

{

	struct snd_compr_file *data = f->private_data;

	struct snd_compr_stream *stream;

	int retval = -ENOTTY;



	if (snd_BUG_ON(!data))

		return -EFAULT;

	stream = &data->stream;

	if (snd_BUG_ON(!stream))

		return -EFAULT;

	mutex_lock(&stream->device->lock);

	switch (_IOC_NR(cmd)) {

	case _IOC_NR(SNDRV_COMPRESS_IOCTL_VERSION):

		put_user(SNDRV_COMPRESS_VERSION,

				(int __user *)arg) ? -EFAULT : 0;

		break;

	case _IOC_NR(SNDRV_COMPRESS_GET_CAPS):

		retval = snd_compr_get_caps(stream, arg);

		break;

	case _IOC_NR(SNDRV_COMPRESS_GET_CODEC_CAPS):

		retval = snd_compr_get_codec_caps(stream, arg);

		break;

	case _IOC_NR(SNDRV_COMPRESS_SET_PARAMS):

		retval = snd_compr_set_params(stream, arg);

		break;

	case _IOC_NR(SNDRV_COMPRESS_GET_PARAMS):

		retval = snd_compr_get_params(stream, arg);

		break;

	case _IOC_NR(SNDRV_COMPRESS_TSTAMP):

		retval = snd_compr_tstamp(stream, arg);

		break;

	case _IOC_NR(SNDRV_COMPRESS_AVAIL):

		retval = snd_compr_ioctl_avail(stream, arg);

		break;

	case _IOC_NR(SNDRV_COMPRESS_PAUSE):

		retval = snd_compr_pause(stream);

		break;

	case _IOC_NR(SNDRV_COMPRESS_RESUME):

		retval = snd_compr_resume(stream);

		break;

	case _IOC_NR(SNDRV_COMPRESS_START):

		retval = snd_compr_start(stream);

		break;

	case _IOC_NR(SNDRV_COMPRESS_STOP):

		retval = snd_compr_stop(stream);

		break;

	case _IOC_NR(SNDRV_COMPRESS_DRAIN):

		retval = snd_compr_drain(stream);

		break;

	}

	mutex_unlock(&stream->device->lock);

	return retval;

}



static const struct file_operations snd_compr_file_ops = {

		.owner =	THIS_MODULE,

		.open =		snd_compr_open,

		.release =	snd_compr_free,

		.write =	snd_compr_write,

		.read =		snd_compr_read,

		.unlocked_ioctl = snd_compr_ioctl,

		.mmap =		snd_compr_mmap,

		.poll =		snd_compr_poll,

};



static int snd_compress_dev_register(struct snd_device *device)

{

	int ret = -EINVAL;

	char str[16];

	struct snd_compr *compr;



	if (snd_BUG_ON(!device || !device->device_data))

		return -EBADFD;

	compr = device->device_data;



	sprintf(str, "comprC%iD%i", compr->card->number, compr->device);

	pr_debug("reg %s for device %s, direction %d\n", str, compr->name,

			compr->direction);

	/* register compressed device */

	ret = snd_register_device(SNDRV_DEVICE_TYPE_COMPRESS, compr->card,

			compr->device, &snd_compr_file_ops, compr, str);

	if (ret < 0) {

		pr_err("snd_register_device failed\n %d", ret);

		return ret;

	}

	return ret;



}



static int snd_compress_dev_disconnect(struct snd_device *device)

{

	struct snd_compr *compr;



	compr = device->device_data;

	snd_unregister_device(compr->direction, compr->card, compr->device);

	return 0;

}



/*

 * snd_compress_new: create new compress device

 * @card: sound card pointer

 * @device: device number

 * @dirn: device direction, should be of type enum snd_compr_direction

 * @compr: compress device pointer

 */

int snd_compress_new(struct snd_card *card, int device,

			int dirn, struct snd_compr *compr)

{

	static struct snd_device_ops ops = {

		.dev_free = NULL,

		.dev_register = snd_compress_dev_register,

		.dev_disconnect = snd_compress_dev_disconnect,

	};



	compr->card = card;

	compr->device = device;

	compr->direction = dirn;

	return snd_device_new(card, SNDRV_DEV_COMPRESS, compr, &ops);

}

EXPORT_SYMBOL_GPL(snd_compress_new);



static int snd_compress_add_device(struct snd_compr *device)

{

	int ret;



	if (!device->card)

		return -EINVAL;



	/* register the card */

	ret = snd_card_register(device->card);

	if (ret)

		goto out;

	return 0;



out:

	pr_err("failed with %d\n", ret);

	return ret;



}



static int snd_compress_remove_device(struct snd_compr *device)

{

	return snd_card_free(device->card);

}



/**

 * snd_compress_register - register compressed device

 *

 * @device: compressed device to register

 */

int snd_compress_register(struct snd_compr *device)

{

	int retval;



	if (device->name == NULL || device->dev == NULL || device->ops == NULL)

		return -EINVAL;



	pr_debug("Registering compressed device %s\n", device->name);

	if (snd_BUG_ON(!device->ops->open))

		return -EINVAL;

	if (snd_BUG_ON(!device->ops->free))

		return -EINVAL;

	if (snd_BUG_ON(!device->ops->set_params))

		return -EINVAL;

	if (snd_BUG_ON(!device->ops->trigger))

		return -EINVAL;



	mutex_init(&device->lock);



	/* register a compressed card */

	mutex_lock(&device_mutex);

	retval = snd_compress_add_device(device);

	mutex_unlock(&device_mutex);

	return retval;

}

EXPORT_SYMBOL_GPL(snd_compress_register);



int snd_compress_deregister(struct snd_compr *device)

{

	pr_debug("Removing compressed device %s\n", device->name);

	mutex_lock(&device_mutex);

	snd_compress_remove_device(device);

	mutex_unlock(&device_mutex);

	return 0;

}

EXPORT_SYMBOL_GPL(snd_compress_deregister);



static int __init snd_compress_init(void)

{

	return 0;

}



static void __exit snd_compress_exit(void)

{

}



module_init(snd_compress_init);

module_exit(snd_compress_exit);



MODULE_DESCRIPTION("ALSA Compressed offload framework");

MODULE_AUTHOR("Vinod Koul <vinod.koul@linux.intel.com>");

MODULE_LICENSE("GPL v2");