sound/soc/kirkwood/kirkwood-dma.c - kernel/msm-4.9 - Gitiles

 /*
  * kirkwood-dma.c
  *
  * (c) 2010 Arnaud Patard <apatard@mandriva.com>
  * (c) 2010 Arnaud Patard <arnaud.patard@rtp-net.org>
  *
  *  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.
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
 #include <linux/mbus.h>
 #include <sound/soc.h>
 #include "kirkwood.h"

 #define KIRKWOOD_RATES \
 	(SNDRV_PCM_RATE_8000_192000 |		\
 	 SNDRV_PCM_RATE_CONTINUOUS |		\
 	 SNDRV_PCM_RATE_KNOT)

 #define KIRKWOOD_FORMATS \
 	(SNDRV_PCM_FMTBIT_S16_LE | \
 	 SNDRV_PCM_FMTBIT_S24_LE | \
 	 SNDRV_PCM_FMTBIT_S32_LE | \
 	 SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE | \
 	 SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE)

 static struct kirkwood_dma_data *kirkwood_priv(struct snd_pcm_substream *subs)
 {
 	struct snd_soc_pcm_runtime *soc_runtime = subs->private_data;
 	return snd_soc_dai_get_drvdata(soc_runtime->cpu_dai);
 }

 static struct snd_pcm_hardware kirkwood_dma_snd_hw = {
 	.info = (SNDRV_PCM_INFO_INTERLEAVED |
 		 SNDRV_PCM_INFO_MMAP |
 		 SNDRV_PCM_INFO_MMAP_VALID |
 		 SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		 SNDRV_PCM_INFO_PAUSE),
 	.formats		= KIRKWOOD_FORMATS,
 	.rates			= KIRKWOOD_RATES,
 	.rate_min		= 8000,
 	.rate_max		= 384000,
 	.channels_min		= 1,
 	.channels_max		= 8,
 	.buffer_bytes_max	= KIRKWOOD_SND_MAX_BUFFER_BYTES,
 	.period_bytes_min	= KIRKWOOD_SND_MIN_PERIOD_BYTES,
 	.period_bytes_max	= KIRKWOOD_SND_MAX_PERIOD_BYTES,
 	.periods_min		= KIRKWOOD_SND_MIN_PERIODS,
 	.periods_max		= KIRKWOOD_SND_MAX_PERIODS,
 	.fifo_size		= 0,
 };

 static u64 kirkwood_dma_dmamask = DMA_BIT_MASK(32);

 static irqreturn_t kirkwood_dma_irq(int irq, void *dev_id)
 {
 	struct kirkwood_dma_data *priv = dev_id;
 	unsigned long mask, status, cause;

 	mask = readl(priv->io + KIRKWOOD_INT_MASK);
 	status = readl(priv->io + KIRKWOOD_INT_CAUSE) & mask;

 	cause = readl(priv->io + KIRKWOOD_ERR_CAUSE);
 	if (unlikely(cause)) {
 		printk(KERN_WARNING "%s: got err interrupt 0x%lx\n",
 				__func__, cause);
 		writel(cause, priv->io + KIRKWOOD_ERR_CAUSE);
 	}

 	/* we've enabled only bytes interrupts ... */
 	if (status & ~(KIRKWOOD_INT_CAUSE_PLAY_BYTES | \
 			KIRKWOOD_INT_CAUSE_REC_BYTES)) {
 		printk(KERN_WARNING "%s: unexpected interrupt %lx\n",
 			__func__, status);
 		return IRQ_NONE;
 	}

 	/* ack int */
 	writel(status, priv->io + KIRKWOOD_INT_CAUSE);

 	if (status & KIRKWOOD_INT_CAUSE_PLAY_BYTES)
 		snd_pcm_period_elapsed(priv->substream_play);

 	if (status & KIRKWOOD_INT_CAUSE_REC_BYTES)
 		snd_pcm_period_elapsed(priv->substream_rec);

 	return IRQ_HANDLED;
 }

 static void
 kirkwood_dma_conf_mbus_windows(void __iomem *base, int win,
 			       unsigned long dma,
 			       const struct mbus_dram_target_info *dram)
 {
 	int i;

 	/* First disable and clear windows */
 	writel(0, base + KIRKWOOD_AUDIO_WIN_CTRL_REG(win));
 	writel(0, base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));

 	/* try to find matching cs for current dma address */
 	for (i = 0; i < dram->num_cs; i++) {
 		const struct mbus_dram_window *cs = dram->cs + i;
 		if ((cs->base & 0xffff0000) < (dma & 0xffff0000)) {
 			writel(cs->base & 0xffff0000,
 				base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));
 			writel(((cs->size - 1) & 0xffff0000) |
 				(cs->mbus_attr << 8) |
 				(dram->mbus_dram_target_id << 4) | 1,
 				base + KIRKWOOD_AUDIO_WIN_CTRL_REG(win));
 		}
 	}
 }

 static int kirkwood_dma_open(struct snd_pcm_substream *substream)
 {
 	int err;
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct kirkwood_dma_data *priv = kirkwood_priv(substream);
 	const struct mbus_dram_target_info *dram;
 	unsigned long addr;

 	snd_soc_set_runtime_hwparams(substream, &kirkwood_dma_snd_hw);

 	/* Ensure that all constraints linked to dma burst are fulfilled */
 	err = snd_pcm_hw_constraint_minmax(runtime,
 			SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
 			priv->burst * 2,
 			KIRKWOOD_AUDIO_BUF_MAX-1);
 	if (err < 0)
 		return err;

 	err = snd_pcm_hw_constraint_step(runtime, 0,
 			SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
 			priv->burst);
 	if (err < 0)
 		return err;

 	err = snd_pcm_hw_constraint_step(substream->runtime, 0,
 			 SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
 			 priv->burst);
 	if (err < 0)
 		return err;

 	if (!priv->substream_play && !priv->substream_rec) {
 		err = request_irq(priv->irq, kirkwood_dma_irq, IRQF_SHARED,
 				  "kirkwood-i2s", priv);
 		if (err)
 			return -EBUSY;

 		/*
 		 * Enable Error interrupts. We're only ack'ing them but
 		 * it's useful for diagnostics
 		 */
 		writel((unsigned long)-1, priv->io + KIRKWOOD_ERR_MASK);
 	}

 	dram = mv_mbus_dram_info();
 	addr = substream->dma_buffer.addr;
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		priv->substream_play = substream;
 		kirkwood_dma_conf_mbus_windows(priv->io,
 			KIRKWOOD_PLAYBACK_WIN, addr, dram);
 	} else {
 		priv->substream_rec = substream;
 		kirkwood_dma_conf_mbus_windows(priv->io,
 			KIRKWOOD_RECORD_WIN, addr, dram);
 	}

 	return 0;
 }

 static int kirkwood_dma_close(struct snd_pcm_substream *substream)
 {
 	struct kirkwood_dma_data *priv = kirkwood_priv(substream);

 	if (!priv)
 		return 0;

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		priv->substream_play = NULL;
 	else
 		priv->substream_rec = NULL;

 	if (!priv->substream_play && !priv->substream_rec) {
 		writel(0, priv->io + KIRKWOOD_ERR_MASK);
 		free_irq(priv->irq, priv);
 	}

 	return 0;
 }

 static int kirkwood_dma_hw_params(struct snd_pcm_substream *substream,
 				struct snd_pcm_hw_params *params)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;

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

 	return 0;
 }

 static int kirkwood_dma_hw_free(struct snd_pcm_substream *substream)
 {
 	snd_pcm_set_runtime_buffer(substream, NULL);
 	return 0;
 }

 static int kirkwood_dma_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct kirkwood_dma_data *priv = kirkwood_priv(substream);
 	unsigned long size, count;

 	/* compute buffer size in term of "words" as requested in specs */
 	size = frames_to_bytes(runtime, runtime->buffer_size);
 	size = (size>>2)-1;
 	count = snd_pcm_lib_period_bytes(substream);

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		writel(count, priv->io + KIRKWOOD_PLAY_BYTE_INT_COUNT);
 		writel(runtime->dma_addr, priv->io + KIRKWOOD_PLAY_BUF_ADDR);
 		writel(size, priv->io + KIRKWOOD_PLAY_BUF_SIZE);
 	} else {
 		writel(count, priv->io + KIRKWOOD_REC_BYTE_INT_COUNT);
 		writel(runtime->dma_addr, priv->io + KIRKWOOD_REC_BUF_ADDR);
 		writel(size, priv->io + KIRKWOOD_REC_BUF_SIZE);
 	}


 	return 0;
 }

 static snd_pcm_uframes_t kirkwood_dma_pointer(struct snd_pcm_substream
 						*substream)
 {
 	struct kirkwood_dma_data *priv = kirkwood_priv(substream);
 	snd_pcm_uframes_t count;

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		count = bytes_to_frames(substream->runtime,
 			readl(priv->io + KIRKWOOD_PLAY_BYTE_COUNT));
 	else
 		count = bytes_to_frames(substream->runtime,
 			readl(priv->io + KIRKWOOD_REC_BYTE_COUNT));

 	return count;
 }

 static struct snd_pcm_ops kirkwood_dma_ops = {
 	.open =		kirkwood_dma_open,
 	.close =        kirkwood_dma_close,
 	.ioctl =	snd_pcm_lib_ioctl,
 	.hw_params =	kirkwood_dma_hw_params,
 	.hw_free =      kirkwood_dma_hw_free,
 	.prepare =      kirkwood_dma_prepare,
 	.pointer =	kirkwood_dma_pointer,
 };

 static int kirkwood_dma_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 = kirkwood_dma_snd_hw.buffer_bytes_max;

 	buf->dev.type = SNDRV_DMA_TYPE_DEV;
 	buf->dev.dev = pcm->card->dev;
 	buf->area = dma_alloc_coherent(pcm->card->dev, size,
 			&buf->addr, GFP_KERNEL);
 	if (!buf->area)
 		return -ENOMEM;
 	buf->bytes = size;
 	buf->private_data = NULL;

 	return 0;
 }

 static int kirkwood_dma_new(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_card *card = rtd->card->snd_card;
 	struct snd_pcm *pcm = rtd->pcm;
 	int ret;

 	if (!card->dev->dma_mask)
 		card->dev->dma_mask = &kirkwood_dma_dmamask;
 	if (!card->dev->coherent_dma_mask)
 		card->dev->coherent_dma_mask = DMA_BIT_MASK(32);

 	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
 		ret = kirkwood_dma_preallocate_dma_buffer(pcm,
 				SNDRV_PCM_STREAM_PLAYBACK);
 		if (ret)
 			return ret;
 	}

 	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
 		ret = kirkwood_dma_preallocate_dma_buffer(pcm,
 				SNDRV_PCM_STREAM_CAPTURE);
 		if (ret)
 			return ret;
 	}

 	return 0;
 }

 static void kirkwood_dma_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_coherent(pcm->card->dev, buf->bytes,
 				buf->area, buf->addr);
 		buf->area = NULL;
 	}
 }

 struct snd_soc_platform_driver kirkwood_soc_platform = {
 	.ops		= &kirkwood_dma_ops,
 	.pcm_new	= kirkwood_dma_new,
 	.pcm_free	= kirkwood_dma_free_dma_buffers,
 };
	/*
	* kirkwood-dma.c
	*
	* (c) 2010 Arnaud Patard <apatard@mandriva.com>
	* (c) 2010 Arnaud Patard <arnaud.patard@rtp-net.org>
	*
	* 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.
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/io.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/dma-mapping.h>
	#include <linux/mbus.h>
	#include <sound/soc.h>
	#include "kirkwood.h"

	#define KIRKWOOD_RATES \
	(SNDRV_PCM_RATE_8000_192000 \| \
	SNDRV_PCM_RATE_CONTINUOUS \| \
	SNDRV_PCM_RATE_KNOT)

	#define KIRKWOOD_FORMATS \
	(SNDRV_PCM_FMTBIT_S16_LE \| \
	SNDRV_PCM_FMTBIT_S24_LE \| \
	SNDRV_PCM_FMTBIT_S32_LE \| \
	SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE \| \
	SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE)

	static struct kirkwood_dma_data kirkwood_priv(struct snd_pcm_substream subs)
	{
	struct snd_soc_pcm_runtime *soc_runtime = subs->private_data;
	return snd_soc_dai_get_drvdata(soc_runtime->cpu_dai);
	}

	static struct snd_pcm_hardware kirkwood_dma_snd_hw = {
	.info = (SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_BLOCK_TRANSFER \|
	SNDRV_PCM_INFO_PAUSE),
	.formats = KIRKWOOD_FORMATS,
	.rates = KIRKWOOD_RATES,
	.rate_min = 8000,
	.rate_max = 384000,
	.channels_min = 1,
	.channels_max = 8,
	.buffer_bytes_max = KIRKWOOD_SND_MAX_BUFFER_BYTES,
	.period_bytes_min = KIRKWOOD_SND_MIN_PERIOD_BYTES,
	.period_bytes_max = KIRKWOOD_SND_MAX_PERIOD_BYTES,
	.periods_min = KIRKWOOD_SND_MIN_PERIODS,
	.periods_max = KIRKWOOD_SND_MAX_PERIODS,
	.fifo_size = 0,
	};

	static u64 kirkwood_dma_dmamask = DMA_BIT_MASK(32);

	static irqreturn_t kirkwood_dma_irq(int irq, void *dev_id)
	{
	struct kirkwood_dma_data *priv = dev_id;
	unsigned long mask, status, cause;

	mask = readl(priv->io + KIRKWOOD_INT_MASK);
	status = readl(priv->io + KIRKWOOD_INT_CAUSE) & mask;

	cause = readl(priv->io + KIRKWOOD_ERR_CAUSE);
	if (unlikely(cause)) {
	printk(KERN_WARNING "%s: got err interrupt 0x%lx\n",
	__func__, cause);
	writel(cause, priv->io + KIRKWOOD_ERR_CAUSE);
	}

	/* we've enabled only bytes interrupts ... */
	if (status & ~(KIRKWOOD_INT_CAUSE_PLAY_BYTES \| \
	KIRKWOOD_INT_CAUSE_REC_BYTES)) {
	printk(KERN_WARNING "%s: unexpected interrupt %lx\n",
	__func__, status);
	return IRQ_NONE;
	}

	/* ack int */
	writel(status, priv->io + KIRKWOOD_INT_CAUSE);

	if (status & KIRKWOOD_INT_CAUSE_PLAY_BYTES)
	snd_pcm_period_elapsed(priv->substream_play);

	if (status & KIRKWOOD_INT_CAUSE_REC_BYTES)
	snd_pcm_period_elapsed(priv->substream_rec);

	return IRQ_HANDLED;
	}

	static void
	kirkwood_dma_conf_mbus_windows(void __iomem *base, int win,
	unsigned long dma,
	const struct mbus_dram_target_info *dram)
	{
	int i;

	/* First disable and clear windows */
	writel(0, base + KIRKWOOD_AUDIO_WIN_CTRL_REG(win));
	writel(0, base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));

	/* try to find matching cs for current dma address */
	for (i = 0; i < dram->num_cs; i++) {
	const struct mbus_dram_window *cs = dram->cs + i;
	if ((cs->base & 0xffff0000) < (dma & 0xffff0000)) {
	writel(cs->base & 0xffff0000,
	base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));
	writel(((cs->size - 1) & 0xffff0000) \|
	(cs->mbus_attr << 8) \|
	(dram->mbus_dram_target_id << 4) \| 1,
	base + KIRKWOOD_AUDIO_WIN_CTRL_REG(win));
	}
	}
	}

	static int kirkwood_dma_open(struct snd_pcm_substream *substream)
	{
	int err;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct kirkwood_dma_data *priv = kirkwood_priv(substream);
	const struct mbus_dram_target_info *dram;
	unsigned long addr;

	snd_soc_set_runtime_hwparams(substream, &kirkwood_dma_snd_hw);

	/* Ensure that all constraints linked to dma burst are fulfilled */
	err = snd_pcm_hw_constraint_minmax(runtime,
	SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
	priv->burst * 2,
	KIRKWOOD_AUDIO_BUF_MAX-1);
	if (err < 0)
	return err;

	err = snd_pcm_hw_constraint_step(runtime, 0,
	SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
	priv->burst);
	if (err < 0)
	return err;

	err = snd_pcm_hw_constraint_step(substream->runtime, 0,
	SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
	priv->burst);
	if (err < 0)
	return err;

	if (!priv->substream_play && !priv->substream_rec) {
	err = request_irq(priv->irq, kirkwood_dma_irq, IRQF_SHARED,
	"kirkwood-i2s", priv);
	if (err)
	return -EBUSY;

	/*
	* Enable Error interrupts. We're only ack'ing them but
	* it's useful for diagnostics
	*/
	writel((unsigned long)-1, priv->io + KIRKWOOD_ERR_MASK);
	}

	dram = mv_mbus_dram_info();
	addr = substream->dma_buffer.addr;
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	priv->substream_play = substream;
	kirkwood_dma_conf_mbus_windows(priv->io,
	KIRKWOOD_PLAYBACK_WIN, addr, dram);
	} else {
	priv->substream_rec = substream;
	kirkwood_dma_conf_mbus_windows(priv->io,
	KIRKWOOD_RECORD_WIN, addr, dram);
	}

	return 0;
	}

	static int kirkwood_dma_close(struct snd_pcm_substream *substream)
	{
	struct kirkwood_dma_data *priv = kirkwood_priv(substream);

	if (!priv)
	return 0;

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	priv->substream_play = NULL;
	else
	priv->substream_rec = NULL;

	if (!priv->substream_play && !priv->substream_rec) {
	writel(0, priv->io + KIRKWOOD_ERR_MASK);
	free_irq(priv->irq, priv);
	}

	return 0;
	}

	static int kirkwood_dma_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;

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

	return 0;
	}

	static int kirkwood_dma_hw_free(struct snd_pcm_substream *substream)
	{
	snd_pcm_set_runtime_buffer(substream, NULL);
	return 0;
	}

	static int kirkwood_dma_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct kirkwood_dma_data *priv = kirkwood_priv(substream);
	unsigned long size, count;

	/* compute buffer size in term of "words" as requested in specs */
	size = frames_to_bytes(runtime, runtime->buffer_size);
	size = (size>>2)-1;
	count = snd_pcm_lib_period_bytes(substream);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	writel(count, priv->io + KIRKWOOD_PLAY_BYTE_INT_COUNT);
	writel(runtime->dma_addr, priv->io + KIRKWOOD_PLAY_BUF_ADDR);
	writel(size, priv->io + KIRKWOOD_PLAY_BUF_SIZE);
	} else {
	writel(count, priv->io + KIRKWOOD_REC_BYTE_INT_COUNT);
	writel(runtime->dma_addr, priv->io + KIRKWOOD_REC_BUF_ADDR);
	writel(size, priv->io + KIRKWOOD_REC_BUF_SIZE);
	}


	return 0;
	}

	static snd_pcm_uframes_t kirkwood_dma_pointer(struct snd_pcm_substream
	*substream)
	{
	struct kirkwood_dma_data *priv = kirkwood_priv(substream);
	snd_pcm_uframes_t count;

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	count = bytes_to_frames(substream->runtime,
	readl(priv->io + KIRKWOOD_PLAY_BYTE_COUNT));
	else
	count = bytes_to_frames(substream->runtime,
	readl(priv->io + KIRKWOOD_REC_BYTE_COUNT));

	return count;
	}

	static struct snd_pcm_ops kirkwood_dma_ops = {
	.open = kirkwood_dma_open,
	.close = kirkwood_dma_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = kirkwood_dma_hw_params,
	.hw_free = kirkwood_dma_hw_free,
	.prepare = kirkwood_dma_prepare,
	.pointer = kirkwood_dma_pointer,
	};

	static int kirkwood_dma_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 = kirkwood_dma_snd_hw.buffer_bytes_max;

	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	buf->dev.dev = pcm->card->dev;
	buf->area = dma_alloc_coherent(pcm->card->dev, size,
	&buf->addr, GFP_KERNEL);
	if (!buf->area)
	return -ENOMEM;
	buf->bytes = size;
	buf->private_data = NULL;

	return 0;
	}

	static int kirkwood_dma_new(struct snd_soc_pcm_runtime *rtd)
	{
	struct snd_card *card = rtd->card->snd_card;
	struct snd_pcm *pcm = rtd->pcm;
	int ret;

	if (!card->dev->dma_mask)
	card->dev->dma_mask = &kirkwood_dma_dmamask;
	if (!card->dev->coherent_dma_mask)
	card->dev->coherent_dma_mask = DMA_BIT_MASK(32);

	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
	ret = kirkwood_dma_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_PLAYBACK);
	if (ret)
	return ret;
	}

	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
	ret = kirkwood_dma_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_CAPTURE);
	if (ret)
	return ret;
	}

	return 0;
	}

	static void kirkwood_dma_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_coherent(pcm->card->dev, buf->bytes,
	buf->area, buf->addr);
	buf->area = NULL;
	}
	}

	struct snd_soc_platform_driver kirkwood_soc_platform = {
	.ops = &kirkwood_dma_ops,
	.pcm_new = kirkwood_dma_new,
	.pcm_free = kirkwood_dma_free_dma_buffers,
	};