au1x00.c

/*
 * BRIEF MODULE DESCRIPTION
 *  Driver for AMD Au1000 MIPS Processor, AC'97 Sound Port
 *
 * Copyright 2004 Cooper Street Innovations Inc.
 * Author: Charles Eidsness	<charles@cooper-street.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;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * History:
 *
 * 2004-09-09 Charles Eidsness	-- Original verion -- based on
 * 				  sa11xx-uda1341.c ALSA driver and the
 *				  au1000.c OSS driver.
 * 2004-09-09 Matt Porter	-- Added support for ALSA 1.0.6
 *
 */

#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/ac97_codec.h>
#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/au1000_dma.h>

MODULE_AUTHOR("Charles Eidsness <charles@cooper-street.com>");
MODULE_DESCRIPTION("Au1000 AC'97 ALSA Driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{AMD,Au1000 AC'97}}");

#define PLAYBACK 0
#define CAPTURE 1
#define AC97_SLOT_3 0x01
#define AC97_SLOT_4 0x02
#define AC97_SLOT_6 0x08
#define AC97_CMD_IRQ 31
#define READ 0
#define WRITE 1
#define READ_WAIT 2
#define RW_DONE 3

struct au1000_period
{
	u32 start;
	u32 relative_end;	/*realtive to start of buffer*/
	struct au1000_period * next;
};

/*Au1000 AC97 Port Control Reisters*/
struct au1000_ac97_reg {
	u32 volatile config;
	u32 volatile status;
	u32 volatile data;
	u32 volatile cmd;
	u32 volatile cntrl;
};

struct audio_stream {
	struct snd_pcm_substream *substream;
	int dma;
	spinlock_t dma_lock;
	struct au1000_period * buffer;
	unsigned int period_size;
	unsigned int periods;
};

struct snd_au1000 {
	struct snd_card *card;
	struct au1000_ac97_reg volatile *ac97_ioport;

	struct resource *ac97_res_port;
	spinlock_t ac97_lock;
	struct snd_ac97 *ac97;

	struct snd_pcm *pcm;
	struct audio_stream *stream[2];	/* playback & capture */
};

/*--------------------------- Local Functions --------------------------------*/
static void
au1000_set_ac97_xmit_slots(struct snd_au1000 *au1000, long xmit_slots)
{
	u32 volatile ac97_config;

	spin_lock(&au1000->ac97_lock);
	ac97_config = au1000->ac97_ioport->config;
	ac97_config = ac97_config & ~AC97C_XMIT_SLOTS_MASK;
	ac97_config |= (xmit_slots << AC97C_XMIT_SLOTS_BIT);
	au1000->ac97_ioport->config = ac97_config;
	spin_unlock(&au1000->ac97_lock);
}

static void
au1000_set_ac97_recv_slots(struct snd_au1000 *au1000, long recv_slots)
{
	u32 volatile ac97_config;

	spin_lock(&au1000->ac97_lock);
	ac97_config = au1000->ac97_ioport->config;
	ac97_config = ac97_config & ~AC97C_RECV_SLOTS_MASK;
	ac97_config |= (recv_slots << AC97C_RECV_SLOTS_BIT);
	au1000->ac97_ioport->config = ac97_config;
	spin_unlock(&au1000->ac97_lock);
}


static void
au1000_release_dma_link(struct audio_stream *stream)
{
	struct au1000_period * pointer;
	struct au1000_period * pointer_next;

	stream->period_size = 0;
	stream->periods = 0;
	pointer = stream->buffer;
	if (! pointer)
		return;
	do {
		pointer_next = pointer->next;
		kfree(pointer);
		pointer = pointer_next;
	} while (pointer != stream->buffer);
	stream->buffer = NULL;
}

static int
au1000_setup_dma_link(struct audio_stream *stream, unsigned int period_bytes,
		      unsigned int periods)
{
	struct snd_pcm_substream *substream = stream->substream;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct au1000_period *pointer;
	unsigned long dma_start;
	int i;

	dma_start = virt_to_phys(runtime->dma_area);

	if (stream->period_size == period_bytes &&
	    stream->periods == periods)
		return 0; /* not changed */

	au1000_release_dma_link(stream);

	stream->period_size = period_bytes;
	stream->periods = periods;

	stream->buffer = kmalloc(sizeof(struct au1000_period), GFP_KERNEL);
	if (! stream->buffer)
		return -ENOMEM;
	pointer = stream->buffer;
	for (i = 0; i < periods; i++) {
		pointer->start = (u32)(dma_start + (i * period_bytes));
		pointer->relative_end = (u32) (((i+1) * period_bytes) - 0x1);
		if (i < periods - 1) {
			pointer->next = kmalloc(sizeof(struct au1000_period), GFP_KERNEL);
			if (! pointer->next) {
				au1000_release_dma_link(stream);
				return -ENOMEM;
			}
			pointer = pointer->next;
		}
	}
	pointer->next = stream->buffer;
	return 0;
}

static void
au1000_dma_stop(struct audio_stream *stream)
{
	snd_assert(stream->buffer, return);
	disable_dma(stream->dma);
}

static void
au1000_dma_start(struct audio_stream *stream)
{
	snd_assert(stream->buffer, return);

	init_dma(stream->dma);
	if (get_dma_active_buffer(stream->dma) == 0) {
		clear_dma_done0(stream->dma);
		set_dma_addr0(stream->dma, stream->buffer->start);
		set_dma_count0(stream->dma, stream->period_size >> 1);
		set_dma_addr1(stream->dma, stream->buffer->next->start);
		set_dma_count1(stream->dma, stream->period_size >> 1);
	} else {
		clear_dma_done1(stream->dma);
		set_dma_addr1(stream->dma, stream->buffer->start);
		set_dma_count1(stream->dma, stream->period_size >> 1);
		set_dma_addr0(stream->dma, stream->buffer->next->start);
		set_dma_count0(stream->dma, stream->period_size >> 1);
	}
	enable_dma_buffers(stream->dma);
	start_dma(stream->dma);
}

static irqreturn_t
au1000_dma_interrupt(int irq, void *dev_id)
{
	struct audio_stream *stream = (struct audio_stream *) dev_id;
	struct snd_pcm_substream *substream = stream->substream;

	spin_lock(&stream->dma_lock);
	switch (get_dma_buffer_done(stream->dma)) {
	case DMA_D0:
		stream->buffer = stream->buffer->next;
		clear_dma_done0(stream->dma);
		set_dma_addr0(stream->dma, stream->buffer->next->start);
		set_dma_count0(stream->dma, stream->period_size >> 1);
		enable_dma_buffer0(stream->dma);
		break;
	case DMA_D1:
		stream->buffer = stream->buffer->next;
		clear_dma_done1(stream->dma);
		set_dma_addr1(stream->dma, stream->buffer->next->start);
		set_dma_count1(stream->dma, stream->period_size >> 1);
		enable_dma_buffer1(stream->dma);
		break;
	case (DMA_D0 | DMA_D1):
		printk(KERN_ERR "DMA %d missed interrupt.\n",stream->dma);
		au1000_dma_stop(stream);
		au1000_dma_start(stream);
		break;
	case (~DMA_D0 & ~DMA_D1):
		printk(KERN_ERR "DMA %d empty irq.\n",stream->dma);
	}
	spin_unlock(&stream->dma_lock);
	snd_pcm_period_elapsed(substream);
	return IRQ_HANDLED;
}

/*-------------------------- PCM Audio Streams -------------------------------*/

static unsigned int rates[] = {8000, 11025, 16000, 22050};
static struct snd_pcm_hw_constraint_list hw_constraints_rates = {
	.count	= ARRAY_SIZE(rates),
	.list	= rates,
	.mask	= 0,
};

static struct snd_pcm_hardware snd_au1000_hw =
{
	.info			= (SNDRV_PCM_INFO_INTERLEAVED | \
				SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
	.formats		= SNDRV_PCM_FMTBIT_S16_LE,
	.rates			= (SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_11025 |
				SNDRV_PCM_RATE_16000 | SNDRV_PCM_RATE_22050),
	.rate_min		= 8000,
	.rate_max		= 22050,
	.channels_min		= 1,
	.channels_max		= 2,
	.buffer_bytes_max	= 128*1024,
	.period_bytes_min	= 32,
	.period_bytes_max	= 16*1024,
	.periods_min		= 8,
	.periods_max		= 255,
	.fifo_size		= 16,
};

static int
snd_au1000_playback_open(struct snd_pcm_substream *substream)
{
	struct snd_au1000 *au1000 = substream->pcm->private_data;

	au1000->stream[PLAYBACK]->substream = substream;
	au1000->stream[PLAYBACK]->buffer = NULL;
	substream->private_data = au1000->stream[PLAYBACK];
	substream->runtime->hw = snd_au1000_hw;
	return (snd_pcm_hw_constraint_list(substream->runtime, 0,
		SNDRV_PCM_HW_PARAM_RATE, &hw_constraints_rates) < 0);
}

static int
snd_au1000_capture_open(struct snd_pcm_substream *substream)
{
	struct snd_au1000 *au1000 = substream->pcm->private_data;

	au1000->stream[CAPTURE]->substream = substream;
	au1000->stream[CAPTURE]->buffer = NULL;
	substream->private_data = au1000->stream[CAPTURE];
	substream->runtime->hw = snd_au1000_hw;
	return (snd_pcm_hw_constraint_list(substream->runtime, 0,
		SNDRV_PCM_HW_PARAM_RATE, &hw_constraints_rates) < 0);
}

static int
snd_au1000_playback_close(struct snd_pcm_substream *substream)
{
	struct snd_au1000 *au1000 = substream->pcm->private_data;

	au1000->stream[PLAYBACK]->substream = NULL;
	return 0;
}

static int
snd_au1000_capture_close(struct snd_pcm_substream *substream)
{
	struct snd_au1000 *au1000 = substream->pcm->private_data;

	au1000->stream[CAPTURE]->substream = NULL;
	return 0;
}

static int
snd_au1000_hw_params(struct snd_pcm_substream *substream,
					struct snd_pcm_hw_params *hw_params)
{
	struct audio_stream *stream = substream->private_data;
	int err;

	err = snd_pcm_lib_malloc_pages(substream,
				       params_buffer_bytes(hw_params));
	if (err < 0)
		return err;
	return au1000_setup_dma_link(stream,
				     params_period_bytes(hw_params),
				     params_periods(hw_params));
}

static int
snd_au1000_hw_free(struct snd_pcm_substream *substream)
{
	struct audio_stream *stream = substream->private_data;
	au1000_release_dma_link(stream);
	return snd_pcm_lib_free_pages(substream);
}

static int
snd_au1000_playback_prepare(struct snd_pcm_substream *substream)
{
	struct snd_au1000 *au1000 = substream->pcm->private_data;
	struct snd_pcm_runtime *runtime = substream->runtime;

	if (runtime->channels == 1)
		au1000_set_ac97_xmit_slots(au1000, AC97_SLOT_4);
	else
		au1000_set_ac97_xmit_slots(au1000, AC97_SLOT_3 | AC97_SLOT_4);
	snd_ac97_set_rate(au1000->ac97, AC97_PCM_FRONT_DAC_RATE, runtime->rate);
	return 0;
}

static int
snd_au1000_capture_prepare(struct snd_pcm_substream *substream)
{
	struct snd_au1000 *au1000 = substream->pcm->private_data;
	struct snd_pcm_runtime *runtime = substream->runtime;

	if (runtime->channels == 1)
		au1000_set_ac97_recv_slots(au1000, AC97_SLOT_4);
	else
		au1000_set_ac97_recv_slots(au1000, AC97_SLOT_3 | AC97_SLOT_4);
	snd_ac97_set_rate(au1000->ac97, AC97_PCM_LR_ADC_RATE, runtime->rate);
	return 0;
}

static int
snd_au1000_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct audio_stream *stream = substream->private_data;
	int err = 0;

	spin_lock(&stream->dma_lock);
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		au1000_dma_start(stream);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
		au1000_dma_stop(stream);
		break;
	default:
		err = -EINVAL;
		break;
	}
	spin_unlock(&stream->dma_lock);
	return err;
}

static snd_pcm_uframes_t
snd_au1000_pointer(struct snd_pcm_substream *substream)
{
	struct audio_stream *stream = substream->private_data;
	struct snd_pcm_runtime *runtime = substream->runtime;
	long location;

	spin_lock(&stream->dma_lock);
	location = get_dma_residue(stream->dma);
	spin_unlock(&stream->dma_lock);
	location = stream->buffer->relative_end - location;
	if (location == -1)
		location = 0;
	return bytes_to_frames(runtime,location);
}

static struct snd_pcm_ops snd_card_au1000_playback_ops = {
	.open			= snd_au1000_playback_open,
	.close			= snd_au1000_playback_close,
	.ioctl			= snd_pcm_lib_ioctl,
	.hw_params	        = snd_au1000_hw_params,
	.hw_free	        = snd_au1000_hw_free,
	.prepare		= snd_au1000_playback_prepare,
	.trigger		= snd_au1000_trigger,
	.pointer		= snd_au1000_pointer,
};

static struct snd_pcm_ops snd_card_au1000_capture_ops = {
	.open			= snd_au1000_capture_open,
	.close			= snd_au1000_capture_close,
	.ioctl			= snd_pcm_lib_ioctl,
	.hw_params	        = snd_au1000_hw_params,
	.hw_free	        = snd_au1000_hw_free,
	.prepare		= snd_au1000_capture_prepare,
	.trigger		= snd_au1000_trigger,
	.pointer		= snd_au1000_pointer,
};

static int __devinit
snd_au1000_pcm_new(struct snd_au1000 *au1000)
{
	struct snd_pcm *pcm;
	int err;
	unsigned long flags;

	if ((err = snd_pcm_new(au1000->card, "AU1000 AC97 PCM", 0, 1, 1, &pcm)) < 0)
		return err;

	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
		snd_dma_continuous_data(GFP_KERNEL), 128*1024, 128*1024);

	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
		&snd_card_au1000_playback_ops);
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
		&snd_card_au1000_capture_ops);

	pcm->private_data = au1000;
	pcm->info_flags = 0;
	strcpy(pcm->name, "Au1000 AC97 PCM");

	spin_lock_init(&au1000->stream[PLAYBACK]->dma_lock);
	spin_lock_init(&au1000->stream[CAPTURE]->dma_lock);

	flags = claim_dma_lock();
	if ((au1000->stream[PLAYBACK]->dma = request_au1000_dma(DMA_ID_AC97C_TX,
			"AC97 TX", au1000_dma_interrupt, IRQF_DISABLED,
			au1000->stream[PLAYBACK])) < 0) {
		release_dma_lock(flags);
		return -EBUSY;
	}
	if ((au1000->stream[CAPTURE]->dma = request_au1000_dma(DMA_ID_AC97C_RX,
			"AC97 RX", au1000_dma_interrupt, IRQF_DISABLED,
			au1000->stream[CAPTURE])) < 0){
		release_dma_lock(flags);
		return -EBUSY;
	}
	/* enable DMA coherency in read/write DMA channels */
	set_dma_mode(au1000->stream[PLAYBACK]->dma,
		     get_dma_mode(au1000->stream[PLAYBACK]->dma) & ~DMA_NC);
	set_dma_mode(au1000->stream[CAPTURE]->dma,
		     get_dma_mode(au1000->stream[CAPTURE]->dma) & ~DMA_NC);
	release_dma_lock(flags);
	au1000->pcm = pcm;
	return 0;
}


/*-------------------------- AC97 CODEC Control ------------------------------*/

static unsigned short
snd_au1000_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
{
	struct snd_au1000 *au1000 = ac97->private_data;
	u32 volatile cmd;
	u16 volatile data;
	int             i;

	spin_lock(&au1000->ac97_lock);
/* would rather use the interrupt than this polling but it works and I can't
get the interrupt driven case to work efficiently */
	for (i = 0; i < 0x5000; i++)
		if (!(au1000->ac97_ioport->status & AC97C_CP))
			break;
	if (i == 0x5000)
		printk(KERN_ERR "au1000 AC97: AC97 command read timeout\n");

	cmd = (u32) reg & AC97C_INDEX_MASK;
	cmd |= AC97C_READ;
	au1000->ac97_ioport->cmd = cmd;

	/* now wait for the data */
	for (i = 0; i < 0x5000; i++)
		if (!(au1000->ac97_ioport->status & AC97C_CP))
			break;
	if (i == 0x5000) {
		printk(KERN_ERR "au1000 AC97: AC97 command read timeout\n");
		return 0;
	}

	data = au1000->ac97_ioport->cmd & 0xffff;
	spin_unlock(&au1000->ac97_lock);

	return data;

}


static void
snd_au1000_ac97_write(struct snd_ac97 *ac97, unsigned short reg, unsigned short val)
{
	struct snd_au1000 *au1000 = ac97->private_data;
	u32 cmd;
	int i;

	spin_lock(&au1000->ac97_lock);
/* would rather use the interrupt than this polling but it works and I can't
get the interrupt driven case to work efficiently */
	for (i = 0; i < 0x5000; i++)
		if (!(au1000->ac97_ioport->status & AC97C_CP))
			break;
	if (i == 0x5000)
		printk(KERN_ERR "au1000 AC97: AC97 command write timeout\n");

	cmd = (u32) reg & AC97C_INDEX_MASK;
	cmd &= ~AC97C_READ;
	cmd |= ((u32) val << AC97C_WD_BIT);
	au1000->ac97_ioport->cmd = cmd;
	spin_unlock(&au1000->ac97_lock);
}

static int __devinit
snd_au1000_ac97_new(struct snd_au1000 *au1000)
{
	int err;
	struct snd_ac97_bus *pbus;
	struct snd_ac97_template ac97;
 	static struct snd_ac97_bus_ops ops = {
		.write = snd_au1000_ac97_write,
		.read = snd_au1000_ac97_read,
	};

	if ((au1000->ac97_res_port = request_mem_region(CPHYSADDR(AC97C_CONFIG),
	       		0x100000, "Au1x00 AC97")) == NULL) {
		snd_printk(KERN_ERR "ALSA AC97: can't grap AC97 port\n");
		return -EBUSY;
	}
	au1000->ac97_ioport = (struct au1000_ac97_reg *)
		KSEG1ADDR(au1000->ac97_res_port->start);

	spin_lock_init(&au1000->ac97_lock);

	/* configure pins for AC'97
	TODO: move to board_setup.c */
	au_writel(au_readl(SYS_PINFUNC) & ~0x02, SYS_PINFUNC);

	/* Initialise Au1000's AC'97 Control Block */
	au1000->ac97_ioport->cntrl = AC97C_RS | AC97C_CE;
	udelay(10);
	au1000->ac97_ioport->cntrl = AC97C_CE;
	udelay(10);

	/* Initialise External CODEC -- cold reset */
	au1000->ac97_ioport->config = AC97C_RESET;
	udelay(10);
	au1000->ac97_ioport->config = 0x0;
	mdelay(5);

	/* Initialise AC97 middle-layer */
	if ((err = snd_ac97_bus(au1000->card, 0, &ops, au1000, &pbus)) < 0)
 		return err;

	memset(&ac97, 0, sizeof(ac97));
	ac97.private_data = au1000;
	if ((err = snd_ac97_mixer(pbus, &ac97, &au1000->ac97)) < 0)
		return err;

	return 0;
}

/*------------------------------ Setup / Destroy ----------------------------*/

void
snd_au1000_free(struct snd_card *card)
{
	struct snd_au1000 *au1000 = card->private_data;

	if (au1000->ac97_res_port) {
		/* put internal AC97 block into reset */
		au1000->ac97_ioport->cntrl = AC97C_RS;
		au1000->ac97_ioport = NULL;
		release_and_free_resource(au1000->ac97_res_port);
	}

	if (au1000->stream[PLAYBACK]) {
	  	if (au1000->stream[PLAYBACK]->dma >= 0)
			free_au1000_dma(au1000->stream[PLAYBACK]->dma);
		kfree(au1000->stream[PLAYBACK]);
	}

	if (au1000->stream[CAPTURE]) {
		if (au1000->stream[CAPTURE]->dma >= 0)
			free_au1000_dma(au1000->stream[CAPTURE]->dma);
		kfree(au1000->stream[CAPTURE]);
	}
}


static struct snd_card *au1000_card;

static int __init
au1000_init(void)
{
	int err;
	struct snd_card *card;
	struct snd_au1000 *au1000;

	card = snd_card_new(-1, "AC97", THIS_MODULE, sizeof(struct snd_au1000));
	if (card == NULL)
		return -ENOMEM;

	card->private_free = snd_au1000_free;
	au1000 = card->private_data;
	au1000->card = card;

	au1000->stream[PLAYBACK] = kmalloc(sizeof(struct audio_stream), GFP_KERNEL);
	au1000->stream[CAPTURE ] = kmalloc(sizeof(struct audio_stream), GFP_KERNEL);
	/* so that snd_au1000_free will work as intended */
 	au1000->ac97_res_port = NULL;
	if (au1000->stream[PLAYBACK])
		au1000->stream[PLAYBACK]->dma = -1;
	if (au1000->stream[CAPTURE ])
		au1000->stream[CAPTURE ]->dma = -1;

	if (au1000->stream[PLAYBACK] == NULL ||
	    au1000->stream[CAPTURE ] == NULL) {
		snd_card_free(card);
		return -ENOMEM;
	}

	if ((err = snd_au1000_ac97_new(au1000)) < 0 ) {
		snd_card_free(card);
		return err;
	}

	if ((err = snd_au1000_pcm_new(au1000)) < 0) {
		snd_card_free(card);
		return err;
	}

	strcpy(card->driver, "Au1000-AC97");
	strcpy(card->shortname, "AMD Au1000-AC97");
	sprintf(card->longname, "AMD Au1000--AC97 ALSA Driver");

	if ((err = snd_card_register(card)) < 0) {
		snd_card_free(card);
		return err;
	}

	printk( KERN_INFO "ALSA AC97: Driver Initialized\n" );
	au1000_card = card;
	return 0;
}

static void __exit au1000_exit(void)
{
	snd_card_free(au1000_card);
}

module_init(au1000_init);
module_exit(au1000_exit);