sound/soc/fsl/imx-pcm-fiq.c - kernel/msm-4.9 - Gitiles

 /*
  * imx-pcm-fiq.c  --  ALSA Soc Audio Layer
  *
  * Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
  *
  * This code is based on code copyrighted by Freescale,
  * Liam Girdwood, Javier Martin and probably others.
  *
  *  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/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

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

 #include <asm/fiq.h>

 #include <linux/platform_data/asoc-imx-ssi.h>

 #include "imx-ssi.h"

 struct imx_pcm_runtime_data {
 	unsigned int period;
 	int periods;
 	unsigned long offset;
 	unsigned long last_offset;
 	unsigned long size;
 	struct hrtimer hrt;
 	int poll_time_ns;
 	struct snd_pcm_substream *substream;
 	atomic_t running;
 };

 static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
 {
 	struct imx_pcm_runtime_data *iprtd =
 		container_of(hrt, struct imx_pcm_runtime_data, hrt);
 	struct snd_pcm_substream *substream = iprtd->substream;
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct pt_regs regs;
 	unsigned long delta;

 	if (!atomic_read(&iprtd->running))
 		return HRTIMER_NORESTART;

 	get_fiq_regs(&regs);

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		iprtd->offset = regs.ARM_r8 & 0xffff;
 	else
 		iprtd->offset = regs.ARM_r9 & 0xffff;

 	/* How much data have we transferred since the last period report? */
 	if (iprtd->offset >= iprtd->last_offset)
 		delta = iprtd->offset - iprtd->last_offset;
 	else
 		delta = runtime->buffer_size + iprtd->offset
 			- iprtd->last_offset;

 	/* If we've transferred at least a period then report it and
 	 * reset our poll time */
 	if (delta >= iprtd->period) {
 		snd_pcm_period_elapsed(substream);
 		iprtd->last_offset = iprtd->offset;
 	}

 	hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));

 	return HRTIMER_RESTART;
 }

 static struct fiq_handler fh = {
 	.name		= DRV_NAME,
 };

 static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
 				struct snd_pcm_hw_params *params)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

 	iprtd->size = params_buffer_bytes(params);
 	iprtd->periods = params_periods(params);
 	iprtd->period = params_period_bytes(params) ;
 	iprtd->offset = 0;
 	iprtd->last_offset = 0;
 	iprtd->poll_time_ns = 1000000000 / params_rate(params) *
 				params_period_size(params);
 	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

 	return 0;
 }

 static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct imx_pcm_runtime_data *iprtd = runtime->private_data;
 	struct pt_regs regs;

 	get_fiq_regs(&regs);
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		regs.ARM_r8 = (iprtd->period * iprtd->periods - 1) << 16;
 	else
 		regs.ARM_r9 = (iprtd->period * iprtd->periods - 1) << 16;

 	set_fiq_regs(&regs);

 	return 0;
 }

 static int fiq_enable;
 static int imx_pcm_fiq;

 static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		atomic_set(&iprtd->running, 1);
 		hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
 		      HRTIMER_MODE_REL);
 		if (++fiq_enable == 1)
 			enable_fiq(imx_pcm_fiq);

 		break;

 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		atomic_set(&iprtd->running, 0);

 		if (--fiq_enable == 0)
 			disable_fiq(imx_pcm_fiq);

 		break;
 	default:
 		return -EINVAL;
 	}

 	return 0;
 }

 static snd_pcm_uframes_t snd_imx_pcm_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

 	return bytes_to_frames(substream->runtime, iprtd->offset);
 }

 static struct snd_pcm_hardware snd_imx_hardware = {
 	.info = SNDRV_PCM_INFO_INTERLEAVED |
 		SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		SNDRV_PCM_INFO_MMAP |
 		SNDRV_PCM_INFO_MMAP_VALID |
 		SNDRV_PCM_INFO_PAUSE |
 		SNDRV_PCM_INFO_RESUME,
 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
 	.rate_min = 8000,
 	.channels_min = 2,
 	.channels_max = 2,
 	.buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
 	.period_bytes_min = 128,
 	.period_bytes_max = 16 * 1024,
 	.periods_min = 4,
 	.periods_max = 255,
 	.fifo_size = 0,
 };

 static int snd_imx_open(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct imx_pcm_runtime_data *iprtd;
 	int ret;

 	iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);
 	if (iprtd == NULL)
 		return -ENOMEM;
 	runtime->private_data = iprtd;

 	iprtd->substream = substream;

 	atomic_set(&iprtd->running, 0);
 	hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	iprtd->hrt.function = snd_hrtimer_callback;

 	ret = snd_pcm_hw_constraint_integer(substream->runtime,
 			SNDRV_PCM_HW_PARAM_PERIODS);
 	if (ret < 0) {
 		kfree(iprtd);
 		return ret;
 	}

 	snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
 	return 0;
 }

 static int snd_imx_close(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

 	hrtimer_cancel(&iprtd->hrt);

 	kfree(iprtd);

 	return 0;
 }

 static int snd_imx_pcm_mmap(struct snd_pcm_substream *substream,
 		struct vm_area_struct *vma)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int ret;

 	ret = dma_mmap_writecombine(substream->pcm->card->dev, vma,
 		runtime->dma_area, runtime->dma_addr, runtime->dma_bytes);

 	pr_debug("%s: ret: %d %p 0x%08x 0x%08x\n", __func__, ret,
 			runtime->dma_area,
 			runtime->dma_addr,
 			runtime->dma_bytes);
 	return ret;
 }

 static struct snd_pcm_ops imx_pcm_ops = {
 	.open		= snd_imx_open,
 	.close		= snd_imx_close,
 	.ioctl		= snd_pcm_lib_ioctl,
 	.hw_params	= snd_imx_pcm_hw_params,
 	.prepare	= snd_imx_pcm_prepare,
 	.trigger	= snd_imx_pcm_trigger,
 	.pointer	= snd_imx_pcm_pointer,
 	.mmap		= snd_imx_pcm_mmap,
 };

 static int imx_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 = IMX_SSI_DMABUF_SIZE;

 	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 u64 imx_pcm_dmamask = DMA_BIT_MASK(32);

 static int imx_pcm_new(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_card *card = rtd->card->snd_card;
 	struct snd_pcm *pcm = rtd->pcm;
 	int ret = 0;

 	if (!card->dev->dma_mask)
 		card->dev->dma_mask = &imx_pcm_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 = imx_pcm_preallocate_dma_buffer(pcm,
 			SNDRV_PCM_STREAM_PLAYBACK);
 		if (ret)
 			goto out;
 	}

 	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
 		ret = imx_pcm_preallocate_dma_buffer(pcm,
 			SNDRV_PCM_STREAM_CAPTURE);
 		if (ret)
 			goto out;
 	}

 out:
 	return ret;
 }

 static int ssi_irq = 0;

 static int imx_pcm_fiq_new(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_pcm *pcm = rtd->pcm;
 	struct snd_pcm_substream *substream;
 	int ret;

 	ret = imx_pcm_new(rtd);
 	if (ret)
 		return ret;

 	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
 	if (substream) {
 		struct snd_dma_buffer *buf = &substream->dma_buffer;

 		imx_ssi_fiq_tx_buffer = (unsigned long)buf->area;
 	}

 	substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
 	if (substream) {
 		struct snd_dma_buffer *buf = &substream->dma_buffer;

 		imx_ssi_fiq_rx_buffer = (unsigned long)buf->area;
 	}

 	set_fiq_handler(&imx_ssi_fiq_start,
 		&imx_ssi_fiq_end - &imx_ssi_fiq_start);

 	return 0;
 }

 static void imx_pcm_free(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 void imx_pcm_fiq_free(struct snd_pcm *pcm)
 {
 	mxc_set_irq_fiq(ssi_irq, 0);
 	release_fiq(&fh);
 	imx_pcm_free(pcm);
 }

 static struct snd_soc_platform_driver imx_soc_platform_fiq = {
 	.ops		= &imx_pcm_ops,
 	.pcm_new	= imx_pcm_fiq_new,
 	.pcm_free	= imx_pcm_fiq_free,
 };

 int imx_pcm_fiq_init(struct platform_device *pdev)
 {
 	struct imx_ssi *ssi = platform_get_drvdata(pdev);
 	int ret;

 	ret = claim_fiq(&fh);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to claim fiq: %d", ret);
 		return ret;
 	}

 	mxc_set_irq_fiq(ssi->irq, 1);
 	ssi_irq = ssi->irq;

 	imx_pcm_fiq = ssi->irq;

 	imx_ssi_fiq_base = (unsigned long)ssi->base;

 	ssi->dma_params_tx.maxburst = 4;
 	ssi->dma_params_rx.maxburst = 6;

 	ret = snd_soc_register_platform(&pdev->dev, &imx_soc_platform_fiq);
 	if (ret)
 		goto failed_register;

 	return 0;

 failed_register:
 	mxc_set_irq_fiq(ssi_irq, 0);
 	release_fiq(&fh);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(imx_pcm_fiq_init);

 void imx_pcm_fiq_exit(struct platform_device *pdev)
 {
 	snd_soc_unregister_platform(&pdev->dev);
 }
 EXPORT_SYMBOL_GPL(imx_pcm_fiq_exit);
	/*
	* imx-pcm-fiq.c -- ALSA Soc Audio Layer
	*
	* Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
	*
	* This code is based on code copyrighted by Freescale,
	* Liam Girdwood, Javier Martin and probably others.
	*
	* 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/clk.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/dma-mapping.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>

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

	#include <asm/fiq.h>

	#include <linux/platform_data/asoc-imx-ssi.h>

	#include "imx-ssi.h"

	struct imx_pcm_runtime_data {
	unsigned int period;
	int periods;
	unsigned long offset;
	unsigned long last_offset;
	unsigned long size;
	struct hrtimer hrt;
	int poll_time_ns;
	struct snd_pcm_substream *substream;
	atomic_t running;
	};

	static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
	{
	struct imx_pcm_runtime_data *iprtd =
	container_of(hrt, struct imx_pcm_runtime_data, hrt);
	struct snd_pcm_substream *substream = iprtd->substream;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct pt_regs regs;
	unsigned long delta;

	if (!atomic_read(&iprtd->running))
	return HRTIMER_NORESTART;

	get_fiq_regs(&regs);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	iprtd->offset = regs.ARM_r8 & 0xffff;
	else
	iprtd->offset = regs.ARM_r9 & 0xffff;

	/* How much data have we transferred since the last period report? */
	if (iprtd->offset >= iprtd->last_offset)
	delta = iprtd->offset - iprtd->last_offset;
	else
	delta = runtime->buffer_size + iprtd->offset
	- iprtd->last_offset;

	/* If we've transferred at least a period then report it and
	* reset our poll time */
	if (delta >= iprtd->period) {
	snd_pcm_period_elapsed(substream);
	iprtd->last_offset = iprtd->offset;
	}

	hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));

	return HRTIMER_RESTART;
	}

	static struct fiq_handler fh = {
	.name = DRV_NAME,
	};

	static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	iprtd->size = params_buffer_bytes(params);
	iprtd->periods = params_periods(params);
	iprtd->period = params_period_bytes(params) ;
	iprtd->offset = 0;
	iprtd->last_offset = 0;
	iprtd->poll_time_ns = 1000000000 / params_rate(params) *
	params_period_size(params);
	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

	return 0;
	}

	static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;
	struct pt_regs regs;

	get_fiq_regs(&regs);
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	regs.ARM_r8 = (iprtd->period * iprtd->periods - 1) << 16;
	else
	regs.ARM_r9 = (iprtd->period * iprtd->periods - 1) << 16;

	set_fiq_regs(&regs);

	return 0;
	}

	static int fiq_enable;
	static int imx_pcm_fiq;

	static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
	atomic_set(&iprtd->running, 1);
	hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
	HRTIMER_MODE_REL);
	if (++fiq_enable == 1)
	enable_fiq(imx_pcm_fiq);

	break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
	atomic_set(&iprtd->running, 0);

	if (--fiq_enable == 0)
	disable_fiq(imx_pcm_fiq);

	break;
	default:
	return -EINVAL;
	}

	return 0;
	}

	static snd_pcm_uframes_t snd_imx_pcm_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	return bytes_to_frames(substream->runtime, iprtd->offset);
	}

	static struct snd_pcm_hardware snd_imx_hardware = {
	.info = SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_BLOCK_TRANSFER \|
	SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_PAUSE \|
	SNDRV_PCM_INFO_RESUME,
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	.rate_min = 8000,
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
	.period_bytes_min = 128,
	.period_bytes_max = 16 * 1024,
	.periods_min = 4,
	.periods_max = 255,
	.fifo_size = 0,
	};

	static int snd_imx_open(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd;
	int ret;

	iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);
	if (iprtd == NULL)
	return -ENOMEM;
	runtime->private_data = iprtd;

	iprtd->substream = substream;

	atomic_set(&iprtd->running, 0);
	hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	iprtd->hrt.function = snd_hrtimer_callback;

	ret = snd_pcm_hw_constraint_integer(substream->runtime,
	SNDRV_PCM_HW_PARAM_PERIODS);
	if (ret < 0) {
	kfree(iprtd);
	return ret;
	}

	snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
	return 0;
	}

	static int snd_imx_close(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	hrtimer_cancel(&iprtd->hrt);

	kfree(iprtd);

	return 0;
	}

	static int snd_imx_pcm_mmap(struct snd_pcm_substream *substream,
	struct vm_area_struct *vma)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int ret;

	ret = dma_mmap_writecombine(substream->pcm->card->dev, vma,
	runtime->dma_area, runtime->dma_addr, runtime->dma_bytes);

	pr_debug("%s: ret: %d %p 0x%08x 0x%08x\n", __func__, ret,
	runtime->dma_area,
	runtime->dma_addr,
	runtime->dma_bytes);
	return ret;
	}

	static struct snd_pcm_ops imx_pcm_ops = {
	.open = snd_imx_open,
	.close = snd_imx_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = snd_imx_pcm_hw_params,
	.prepare = snd_imx_pcm_prepare,
	.trigger = snd_imx_pcm_trigger,
	.pointer = snd_imx_pcm_pointer,
	.mmap = snd_imx_pcm_mmap,
	};

	static int imx_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 = IMX_SSI_DMABUF_SIZE;

	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 u64 imx_pcm_dmamask = DMA_BIT_MASK(32);

	static int imx_pcm_new(struct snd_soc_pcm_runtime *rtd)
	{
	struct snd_card *card = rtd->card->snd_card;
	struct snd_pcm *pcm = rtd->pcm;
	int ret = 0;

	if (!card->dev->dma_mask)
	card->dev->dma_mask = &imx_pcm_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 = imx_pcm_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_PLAYBACK);
	if (ret)
	goto out;
	}

	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
	ret = imx_pcm_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_CAPTURE);
	if (ret)
	goto out;
	}

	out:
	return ret;
	}

	static int ssi_irq = 0;

	static int imx_pcm_fiq_new(struct snd_soc_pcm_runtime *rtd)
	{
	struct snd_pcm *pcm = rtd->pcm;
	struct snd_pcm_substream *substream;
	int ret;

	ret = imx_pcm_new(rtd);
	if (ret)
	return ret;

	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
	if (substream) {
	struct snd_dma_buffer *buf = &substream->dma_buffer;

	imx_ssi_fiq_tx_buffer = (unsigned long)buf->area;
	}

	substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
	if (substream) {
	struct snd_dma_buffer *buf = &substream->dma_buffer;

	imx_ssi_fiq_rx_buffer = (unsigned long)buf->area;
	}

	set_fiq_handler(&imx_ssi_fiq_start,
	&imx_ssi_fiq_end - &imx_ssi_fiq_start);

	return 0;
	}

	static void imx_pcm_free(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 void imx_pcm_fiq_free(struct snd_pcm *pcm)
	{
	mxc_set_irq_fiq(ssi_irq, 0);
	release_fiq(&fh);
	imx_pcm_free(pcm);
	}

	static struct snd_soc_platform_driver imx_soc_platform_fiq = {
	.ops = &imx_pcm_ops,
	.pcm_new = imx_pcm_fiq_new,
	.pcm_free = imx_pcm_fiq_free,
	};

	int imx_pcm_fiq_init(struct platform_device *pdev)
	{
	struct imx_ssi *ssi = platform_get_drvdata(pdev);
	int ret;

	ret = claim_fiq(&fh);
	if (ret) {
	dev_err(&pdev->dev, "failed to claim fiq: %d", ret);
	return ret;
	}

	mxc_set_irq_fiq(ssi->irq, 1);
	ssi_irq = ssi->irq;

	imx_pcm_fiq = ssi->irq;

	imx_ssi_fiq_base = (unsigned long)ssi->base;

	ssi->dma_params_tx.maxburst = 4;
	ssi->dma_params_rx.maxburst = 6;

	ret = snd_soc_register_platform(&pdev->dev, &imx_soc_platform_fiq);
	if (ret)
	goto failed_register;

	return 0;

	failed_register:
	mxc_set_irq_fiq(ssi_irq, 0);
	release_fiq(&fh);

	return ret;
	}
	EXPORT_SYMBOL_GPL(imx_pcm_fiq_init);

	void imx_pcm_fiq_exit(struct platform_device *pdev)
	{
	snd_soc_unregister_platform(&pdev->dev);
	}
	EXPORT_SYMBOL_GPL(imx_pcm_fiq_exit);