sound/soc/pxa/pxa2xx-pcm.c - kernel/msm-4.9 - Gitiles

 /*
  * linux/sound/arm/pxa2xx-pcm.c -- ALSA PCM interface for the Intel PXA2xx chip
  *
  * Author:	Nicolas Pitre
  * Created:	Nov 30, 2004
  * Copyright:	(C) 2004 MontaVista Software, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>

 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/soc.h>

 #include <asm/dma.h>
 #include <asm/hardware.h>
 #include <asm/arch/pxa-regs.h>
 #include <asm/arch/audio.h>

 #include "pxa2xx-pcm.h"

 static const struct snd_pcm_hardware pxa2xx_pcm_hardware = {
 	.info			= SNDRV_PCM_INFO_MMAP |
 				  SNDRV_PCM_INFO_MMAP_VALID |
 				  SNDRV_PCM_INFO_INTERLEAVED |
 				  SNDRV_PCM_INFO_PAUSE |
 				  SNDRV_PCM_INFO_RESUME,
 	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
 					SNDRV_PCM_FMTBIT_S24_LE |
 					SNDRV_PCM_FMTBIT_S32_LE,
 	.period_bytes_min	= 32,
 	.period_bytes_max	= 8192 - 32,
 	.periods_min		= 1,
 	.periods_max		= PAGE_SIZE/sizeof(pxa_dma_desc),
 	.buffer_bytes_max	= 128 * 1024,
 	.fifo_size		= 32,
 };

 struct pxa2xx_runtime_data {
 	int dma_ch;
 	struct pxa2xx_pcm_dma_params *params;
 	pxa_dma_desc *dma_desc_array;
 	dma_addr_t dma_desc_array_phys;
 };

 static void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id)
 {
 	struct snd_pcm_substream *substream = dev_id;
 	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
 	int dcsr;

 	dcsr = DCSR(dma_ch);
 	DCSR(dma_ch) = dcsr & ~DCSR_STOPIRQEN;

 	if (dcsr & DCSR_ENDINTR) {
 		snd_pcm_period_elapsed(substream);
 	} else {
 		printk(KERN_ERR "%s: DMA error on channel %d (DCSR=%#x)\n",
 			prtd->params->name, dma_ch, dcsr);
 	}
 }

 static int pxa2xx_pcm_hw_params(struct snd_pcm_substream *substream,
 	struct snd_pcm_hw_params *params)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct pxa2xx_runtime_data *prtd = runtime->private_data;
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct pxa2xx_pcm_dma_params *dma = rtd->dai->cpu_dai->dma_data;
 	size_t totsize = params_buffer_bytes(params);
 	size_t period = params_period_bytes(params);
 	pxa_dma_desc *dma_desc;
 	dma_addr_t dma_buff_phys, next_desc_phys;
 	int ret;

 	/* return if this is a bufferless transfer e.g.
 	 * codec <--> BT codec or GSM modem -- lg FIXME */
 	if (!dma)
 		return 0;

 	/* this may get called several times by oss emulation
 	 * with different params */
 	if (prtd->params == NULL) {
 		prtd->params = dma;
 		ret = pxa_request_dma(prtd->params->name, DMA_PRIO_LOW,
 			      pxa2xx_pcm_dma_irq, substream);
 		if (ret < 0)
 			return ret;
 		prtd->dma_ch = ret;
 	} else if (prtd->params != dma) {
 		pxa_free_dma(prtd->dma_ch);
 		prtd->params = dma;
 		ret = pxa_request_dma(prtd->params->name, DMA_PRIO_LOW,
 			      pxa2xx_pcm_dma_irq, substream);
 		if (ret < 0)
 			return ret;
 		prtd->dma_ch = ret;
 	}

 	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
 	runtime->dma_bytes = totsize;

 	dma_desc = prtd->dma_desc_array;
 	next_desc_phys = prtd->dma_desc_array_phys;
 	dma_buff_phys = runtime->dma_addr;
 	do {
 		next_desc_phys += sizeof(pxa_dma_desc);
 		dma_desc->ddadr = next_desc_phys;
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 			dma_desc->dsadr = dma_buff_phys;
 			dma_desc->dtadr = prtd->params->dev_addr;
 		} else {
 			dma_desc->dsadr = prtd->params->dev_addr;
 			dma_desc->dtadr = dma_buff_phys;
 		}
 		if (period > totsize)
 			period = totsize;
 		dma_desc->dcmd = prtd->params->dcmd | period | DCMD_ENDIRQEN;
 		dma_desc++;
 		dma_buff_phys += period;
 	} while (totsize -= period);
 	dma_desc[-1].ddadr = prtd->dma_desc_array_phys;

 	return 0;
 }

 static int pxa2xx_pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

 	if (prtd && prtd->params)
 		*prtd->params->drcmr = 0;

 	if (prtd->dma_ch) {
 		snd_pcm_set_runtime_buffer(substream, NULL);
 		pxa_free_dma(prtd->dma_ch);
 		prtd->dma_ch = 0;
 	}

 	return 0;
 }

 static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
 {
 	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

 	DCSR(prtd->dma_ch) &= ~DCSR_RUN;
 	DCSR(prtd->dma_ch) = 0;
 	DCMD(prtd->dma_ch) = 0;
 	*prtd->params->drcmr = prtd->dma_ch | DRCMR_MAPVLD;

 	return 0;
 }

 static int pxa2xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
 	int ret = 0;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
 		DCSR(prtd->dma_ch) = DCSR_RUN;
 		break;

 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		DCSR(prtd->dma_ch) &= ~DCSR_RUN;
 		break;

 	case SNDRV_PCM_TRIGGER_RESUME:
 		DCSR(prtd->dma_ch) |= DCSR_RUN;
 		break;
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
 		DCSR(prtd->dma_ch) |= DCSR_RUN;
 		break;

 	default:
 		ret = -EINVAL;
 	}

 	return ret;
 }

 static snd_pcm_uframes_t
 pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct pxa2xx_runtime_data *prtd = runtime->private_data;

 	dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
 			 DSADR(prtd->dma_ch) : DTADR(prtd->dma_ch);
 	snd_pcm_uframes_t x = bytes_to_frames(runtime, ptr - runtime->dma_addr);

 	if (x == runtime->buffer_size)
 		x = 0;
 	return x;
 }

 static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct pxa2xx_runtime_data *prtd;
 	int ret;

 	snd_soc_set_runtime_hwparams(substream, &pxa2xx_pcm_hardware);

 	/*
 	 * For mysterious reasons (and despite what the manual says)
 	 * playback samples are lost if the DMA count is not a multiple
 	 * of the DMA burst size.  Let's add a rule to enforce that.
 	 */
 	ret = snd_pcm_hw_constraint_step(runtime, 0,
 		SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 32);
 	if (ret)
 		goto out;

 	ret = snd_pcm_hw_constraint_step(runtime, 0,
 		SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 32);
 	if (ret)
 		goto out;

 	ret = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 	if (ret < 0)
 		goto out;

 	prtd = kzalloc(sizeof(struct pxa2xx_runtime_data), GFP_KERNEL);
 	if (prtd == NULL) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	prtd->dma_desc_array =
 		dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
 				       &prtd->dma_desc_array_phys, GFP_KERNEL);
 	if (!prtd->dma_desc_array) {
 		ret = -ENOMEM;
 		goto err1;
 	}

 	runtime->private_data = prtd;
 	return 0;

  err1:
 	kfree(prtd);
  out:
 	return ret;
 }

 static int pxa2xx_pcm_close(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct pxa2xx_runtime_data *prtd = runtime->private_data;

 	dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
 			      prtd->dma_desc_array, prtd->dma_desc_array_phys);
 	kfree(prtd);
 	return 0;
 }

 static int pxa2xx_pcm_mmap(struct snd_pcm_substream *substream,
 	struct vm_area_struct *vma)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
 				     runtime->dma_area,
 				     runtime->dma_addr,
 				     runtime->dma_bytes);
 }

 struct snd_pcm_ops pxa2xx_pcm_ops = {
 	.open		= pxa2xx_pcm_open,
 	.close		= pxa2xx_pcm_close,
 	.ioctl		= snd_pcm_lib_ioctl,
 	.hw_params	= pxa2xx_pcm_hw_params,
 	.hw_free	= pxa2xx_pcm_hw_free,
 	.prepare	= pxa2xx_pcm_prepare,
 	.trigger	= pxa2xx_pcm_trigger,
 	.pointer	= pxa2xx_pcm_pointer,
 	.mmap		= pxa2xx_pcm_mmap,
 };

 static int pxa2xx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
 {
 	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
 	struct snd_dma_buffer *buf = &substream->dma_buffer;
 	size_t size = pxa2xx_pcm_hardware.buffer_bytes_max;
 	buf->dev.type = SNDRV_DMA_TYPE_DEV;
 	buf->dev.dev = pcm->card->dev;
 	buf->private_data = NULL;
 	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
 					   &buf->addr, GFP_KERNEL);
 	if (!buf->area)
 		return -ENOMEM;
 	buf->bytes = size;
 	return 0;
 }

 static void pxa2xx_pcm_free_dma_buffers(struct snd_pcm *pcm)
 {
 	struct snd_pcm_substream *substream;
 	struct snd_dma_buffer *buf;
 	int stream;

 	for (stream = 0; stream < 2; stream++) {
 		substream = pcm->streams[stream].substream;
 		if (!substream)
 			continue;

 		buf = &substream->dma_buffer;
 		if (!buf->area)
 			continue;

 		dma_free_writecombine(pcm->card->dev, buf->bytes,
 				      buf->area, buf->addr);
 		buf->area = NULL;
 	}
 }

 static u64 pxa2xx_pcm_dmamask = DMA_32BIT_MASK;

 int pxa2xx_pcm_new(struct snd_card *card, struct snd_soc_codec_dai *dai,
 	struct snd_pcm *pcm)
 {
 	int ret = 0;

 	if (!card->dev->dma_mask)
 		card->dev->dma_mask = &pxa2xx_pcm_dmamask;
 	if (!card->dev->coherent_dma_mask)
 		card->dev->coherent_dma_mask = DMA_32BIT_MASK;

 	if (dai->playback.channels_min) {
 		ret = pxa2xx_pcm_preallocate_dma_buffer(pcm,
 			SNDRV_PCM_STREAM_PLAYBACK);
 		if (ret)
 			goto out;
 	}

 	if (dai->capture.channels_min) {
 		ret = pxa2xx_pcm_preallocate_dma_buffer(pcm,
 			SNDRV_PCM_STREAM_CAPTURE);
 		if (ret)
 			goto out;
 	}
  out:
 	return ret;
 }

 struct snd_soc_platform pxa2xx_soc_platform = {
 	.name		= "pxa2xx-audio",
 	.pcm_ops 	= &pxa2xx_pcm_ops,
 	.pcm_new	= pxa2xx_pcm_new,
 	.pcm_free	= pxa2xx_pcm_free_dma_buffers,
 };
 EXPORT_SYMBOL_GPL(pxa2xx_soc_platform);

 MODULE_AUTHOR("Nicolas Pitre");
 MODULE_DESCRIPTION("Intel PXA2xx PCM DMA module");
 MODULE_LICENSE("GPL");
	/*
	* linux/sound/arm/pxa2xx-pcm.c -- ALSA PCM interface for the Intel PXA2xx chip
	*
	* Author: Nicolas Pitre
	* Created: Nov 30, 2004
	* Copyright: (C) 2004 MontaVista Software, Inc.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/dma-mapping.h>

	#include <sound/core.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>
	#include <sound/soc.h>

	#include <asm/dma.h>
	#include <asm/hardware.h>
	#include <asm/arch/pxa-regs.h>
	#include <asm/arch/audio.h>

	#include "pxa2xx-pcm.h"

	static const struct snd_pcm_hardware pxa2xx_pcm_hardware = {
	.info = SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_PAUSE \|
	SNDRV_PCM_INFO_RESUME,
	.formats = SNDRV_PCM_FMTBIT_S16_LE \|
	SNDRV_PCM_FMTBIT_S24_LE \|
	SNDRV_PCM_FMTBIT_S32_LE,
	.period_bytes_min = 32,
	.period_bytes_max = 8192 - 32,
	.periods_min = 1,
	.periods_max = PAGE_SIZE/sizeof(pxa_dma_desc),
	.buffer_bytes_max = 128 * 1024,
	.fifo_size = 32,
	};

	struct pxa2xx_runtime_data {
	int dma_ch;
	struct pxa2xx_pcm_dma_params *params;
	pxa_dma_desc *dma_desc_array;
	dma_addr_t dma_desc_array_phys;
	};

	static void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id)
	{
	struct snd_pcm_substream *substream = dev_id;
	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
	int dcsr;

	dcsr = DCSR(dma_ch);
	DCSR(dma_ch) = dcsr & ~DCSR_STOPIRQEN;

	if (dcsr & DCSR_ENDINTR) {
	snd_pcm_period_elapsed(substream);
	} else {
	printk(KERN_ERR "%s: DMA error on channel %d (DCSR=%#x)\n",
	prtd->params->name, dma_ch, dcsr);
	}
	}

	static int pxa2xx_pcm_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct pxa2xx_runtime_data *prtd = runtime->private_data;
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct pxa2xx_pcm_dma_params *dma = rtd->dai->cpu_dai->dma_data;
	size_t totsize = params_buffer_bytes(params);
	size_t period = params_period_bytes(params);
	pxa_dma_desc *dma_desc;
	dma_addr_t dma_buff_phys, next_desc_phys;
	int ret;

	/* return if this is a bufferless transfer e.g.
	* codec <--> BT codec or GSM modem -- lg FIXME */
	if (!dma)
	return 0;

	/* this may get called several times by oss emulation
	* with different params */
	if (prtd->params == NULL) {
	prtd->params = dma;
	ret = pxa_request_dma(prtd->params->name, DMA_PRIO_LOW,
	pxa2xx_pcm_dma_irq, substream);
	if (ret < 0)
	return ret;
	prtd->dma_ch = ret;
	} else if (prtd->params != dma) {
	pxa_free_dma(prtd->dma_ch);
	prtd->params = dma;
	ret = pxa_request_dma(prtd->params->name, DMA_PRIO_LOW,
	pxa2xx_pcm_dma_irq, substream);
	if (ret < 0)
	return ret;
	prtd->dma_ch = ret;
	}

	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
	runtime->dma_bytes = totsize;

	dma_desc = prtd->dma_desc_array;
	next_desc_phys = prtd->dma_desc_array_phys;
	dma_buff_phys = runtime->dma_addr;
	do {
	next_desc_phys += sizeof(pxa_dma_desc);
	dma_desc->ddadr = next_desc_phys;
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	dma_desc->dsadr = dma_buff_phys;
	dma_desc->dtadr = prtd->params->dev_addr;
	} else {
	dma_desc->dsadr = prtd->params->dev_addr;
	dma_desc->dtadr = dma_buff_phys;
	}
	if (period > totsize)
	period = totsize;
	dma_desc->dcmd = prtd->params->dcmd \| period \| DCMD_ENDIRQEN;
	dma_desc++;
	dma_buff_phys += period;
	} while (totsize -= period);
	dma_desc[-1].ddadr = prtd->dma_desc_array_phys;

	return 0;
	}

	static int pxa2xx_pcm_hw_free(struct snd_pcm_substream *substream)
	{
	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

	if (prtd && prtd->params)
	*prtd->params->drcmr = 0;

	if (prtd->dma_ch) {
	snd_pcm_set_runtime_buffer(substream, NULL);
	pxa_free_dma(prtd->dma_ch);
	prtd->dma_ch = 0;
	}

	return 0;
	}

	static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
	{
	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

	DCSR(prtd->dma_ch) &= ~DCSR_RUN;
	DCSR(prtd->dma_ch) = 0;
	DCMD(prtd->dma_ch) = 0;
	*prtd->params->drcmr = prtd->dma_ch \| DRCMR_MAPVLD;

	return 0;
	}

	static int pxa2xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
	int ret = 0;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
	DCSR(prtd->dma_ch) = DCSR_RUN;
	break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
	DCSR(prtd->dma_ch) &= ~DCSR_RUN;
	break;

	case SNDRV_PCM_TRIGGER_RESUME:
	DCSR(prtd->dma_ch) \|= DCSR_RUN;
	break;
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
	DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
	DCSR(prtd->dma_ch) \|= DCSR_RUN;
	break;

	default:
	ret = -EINVAL;
	}

	return ret;
	}

	static snd_pcm_uframes_t
	pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct pxa2xx_runtime_data *prtd = runtime->private_data;

	dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
	DSADR(prtd->dma_ch) : DTADR(prtd->dma_ch);
	snd_pcm_uframes_t x = bytes_to_frames(runtime, ptr - runtime->dma_addr);

	if (x == runtime->buffer_size)
	x = 0;
	return x;
	}

	static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct pxa2xx_runtime_data *prtd;
	int ret;

	snd_soc_set_runtime_hwparams(substream, &pxa2xx_pcm_hardware);

	/*
	* For mysterious reasons (and despite what the manual says)
	* playback samples are lost if the DMA count is not a multiple
	* of the DMA burst size. Let's add a rule to enforce that.
	*/
	ret = snd_pcm_hw_constraint_step(runtime, 0,
	SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 32);
	if (ret)
	goto out;

	ret = snd_pcm_hw_constraint_step(runtime, 0,
	SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 32);
	if (ret)
	goto out;

	ret = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	if (ret < 0)
	goto out;

	prtd = kzalloc(sizeof(struct pxa2xx_runtime_data), GFP_KERNEL);
	if (prtd == NULL) {
	ret = -ENOMEM;
	goto out;
	}

	prtd->dma_desc_array =
	dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
	&prtd->dma_desc_array_phys, GFP_KERNEL);
	if (!prtd->dma_desc_array) {
	ret = -ENOMEM;
	goto err1;
	}

	runtime->private_data = prtd;
	return 0;

	err1:
	kfree(prtd);
	out:
	return ret;
	}

	static int pxa2xx_pcm_close(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct pxa2xx_runtime_data *prtd = runtime->private_data;

	dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
	prtd->dma_desc_array, prtd->dma_desc_array_phys);
	kfree(prtd);
	return 0;
	}

	static int pxa2xx_pcm_mmap(struct snd_pcm_substream *substream,
	struct vm_area_struct *vma)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
	runtime->dma_area,
	runtime->dma_addr,
	runtime->dma_bytes);
	}

	struct snd_pcm_ops pxa2xx_pcm_ops = {
	.open = pxa2xx_pcm_open,
	.close = pxa2xx_pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = pxa2xx_pcm_hw_params,
	.hw_free = pxa2xx_pcm_hw_free,
	.prepare = pxa2xx_pcm_prepare,
	.trigger = pxa2xx_pcm_trigger,
	.pointer = pxa2xx_pcm_pointer,
	.mmap = pxa2xx_pcm_mmap,
	};

	static int pxa2xx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
	{
	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
	struct snd_dma_buffer *buf = &substream->dma_buffer;
	size_t size = pxa2xx_pcm_hardware.buffer_bytes_max;
	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	buf->dev.dev = pcm->card->dev;
	buf->private_data = NULL;
	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
	&buf->addr, GFP_KERNEL);
	if (!buf->area)
	return -ENOMEM;
	buf->bytes = size;
	return 0;
	}

	static void pxa2xx_pcm_free_dma_buffers(struct snd_pcm *pcm)
	{
	struct snd_pcm_substream *substream;
	struct snd_dma_buffer *buf;
	int stream;

	for (stream = 0; stream < 2; stream++) {
	substream = pcm->streams[stream].substream;
	if (!substream)
	continue;

	buf = &substream->dma_buffer;
	if (!buf->area)
	continue;

	dma_free_writecombine(pcm->card->dev, buf->bytes,
	buf->area, buf->addr);
	buf->area = NULL;
	}
	}

	static u64 pxa2xx_pcm_dmamask = DMA_32BIT_MASK;

	int pxa2xx_pcm_new(struct snd_card card, struct snd_soc_codec_dai dai,
	struct snd_pcm *pcm)
	{
	int ret = 0;

	if (!card->dev->dma_mask)
	card->dev->dma_mask = &pxa2xx_pcm_dmamask;
	if (!card->dev->coherent_dma_mask)
	card->dev->coherent_dma_mask = DMA_32BIT_MASK;

	if (dai->playback.channels_min) {
	ret = pxa2xx_pcm_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_PLAYBACK);
	if (ret)
	goto out;
	}

	if (dai->capture.channels_min) {
	ret = pxa2xx_pcm_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_CAPTURE);
	if (ret)
	goto out;
	}
	out:
	return ret;
	}

	struct snd_soc_platform pxa2xx_soc_platform = {
	.name = "pxa2xx-audio",
	.pcm_ops = &pxa2xx_pcm_ops,
	.pcm_new = pxa2xx_pcm_new,
	.pcm_free = pxa2xx_pcm_free_dma_buffers,
	};
	EXPORT_SYMBOL_GPL(pxa2xx_soc_platform);

	MODULE_AUTHOR("Nicolas Pitre");
	MODULE_DESCRIPTION("Intel PXA2xx PCM DMA module");
	MODULE_LICENSE("GPL");