sound/soc/atmel/atmel-pcm-pdc.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * atmel-pcm.c  --  ALSA PCM interface for the Atmel atmel SoC.
  *
  *  Copyright (C) 2005 SAN People
  *  Copyright (C) 2008 Atmel
  *
  * Authors: Sedji Gaouaou <sedji.gaouaou@atmel.com>
  *
  * Based on at91-pcm. by:
  * Frank Mandarino <fmandarino@endrelia.com>
  * Copyright 2006 Endrelia Technologies Inc.
  *
  * Based on pxa2xx-pcm.c by:
  *
  * Author:	Nicolas Pitre
  * Created:	Nov 30, 2004
  * Copyright:	(C) 2004 MontaVista Software, Inc.
  */

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

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

 #include "atmel-pcm.h"


 static int atmel_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 = ATMEL_SSC_DMABUF_SIZE;

 	buf->dev.type = SNDRV_DMA_TYPE_DEV;
 	buf->dev.dev = pcm->card->dev;
 	buf->private_data = NULL;
 	buf->area = dma_alloc_coherent(pcm->card->dev, size,
 			&buf->addr, GFP_KERNEL);
 	pr_debug("atmel-pcm: alloc dma buffer: area=%p, addr=%p, size=%zu\n",
 			(void *)buf->area, (void *)(long)buf->addr, size);

 	if (!buf->area)
 		return -ENOMEM;

 	buf->bytes = size;
 	return 0;
 }

 static int atmel_pcm_mmap(struct snd_pcm_substream *substream,
 	struct vm_area_struct *vma)
 {
 	return remap_pfn_range(vma, vma->vm_start,
 		       substream->dma_buffer.addr >> PAGE_SHIFT,
 		       vma->vm_end - vma->vm_start, vma->vm_page_prot);
 }

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

 	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
 	if (ret)
 		return ret;

 	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
 		pr_debug("atmel-pcm: allocating PCM playback DMA buffer\n");
 		ret = atmel_pcm_preallocate_dma_buffer(pcm,
 			SNDRV_PCM_STREAM_PLAYBACK);
 		if (ret)
 			goto out;
 	}

 	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
 		pr_debug("atmel-pcm: allocating PCM capture DMA buffer\n");
 		ret = atmel_pcm_preallocate_dma_buffer(pcm,
 			SNDRV_PCM_STREAM_CAPTURE);
 		if (ret)
 			goto out;
 	}
  out:
 	return ret;
 }

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

 /*--------------------------------------------------------------------------*\
  * Hardware definition
 \*--------------------------------------------------------------------------*/
 /* TODO: These values were taken from the AT91 platform driver, check
  *	 them against real values for AT32
  */
 static const struct snd_pcm_hardware atmel_pcm_hardware = {
 	.info			= SNDRV_PCM_INFO_MMAP |
 				  SNDRV_PCM_INFO_MMAP_VALID |
 				  SNDRV_PCM_INFO_INTERLEAVED |
 				  SNDRV_PCM_INFO_PAUSE,
 	.period_bytes_min	= 32,
 	.period_bytes_max	= 8192,
 	.periods_min		= 2,
 	.periods_max		= 1024,
 	.buffer_bytes_max	= ATMEL_SSC_DMABUF_SIZE,
 };


 /*--------------------------------------------------------------------------*\
  * Data types
 \*--------------------------------------------------------------------------*/
 struct atmel_runtime_data {
 	struct atmel_pcm_dma_params *params;
 	dma_addr_t dma_buffer;		/* physical address of dma buffer */
 	dma_addr_t dma_buffer_end;	/* first address beyond DMA buffer */
 	size_t period_size;

 	dma_addr_t period_ptr;		/* physical address of next period */
 };

 /*--------------------------------------------------------------------------*\
  * ISR
 \*--------------------------------------------------------------------------*/
 static void atmel_pcm_dma_irq(u32 ssc_sr,
 	struct snd_pcm_substream *substream)
 {
 	struct atmel_runtime_data *prtd = substream->runtime->private_data;
 	struct atmel_pcm_dma_params *params = prtd->params;
 	static int count;

 	count++;

 	if (ssc_sr & params->mask->ssc_endbuf) {
 		pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x, count=%d)\n",
 				substream->stream == SNDRV_PCM_STREAM_PLAYBACK
 				? "underrun" : "overrun",
 				params->name, ssc_sr, count);

 		/* re-start the PDC */
 		ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
 			   params->mask->pdc_disable);
 		prtd->period_ptr += prtd->period_size;
 		if (prtd->period_ptr >= prtd->dma_buffer_end)
 			prtd->period_ptr = prtd->dma_buffer;

 		ssc_writex(params->ssc->regs, params->pdc->xpr,
 			   prtd->period_ptr);
 		ssc_writex(params->ssc->regs, params->pdc->xcr,
 			   prtd->period_size / params->pdc_xfer_size);
 		ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
 			   params->mask->pdc_enable);
 	}

 	if (ssc_sr & params->mask->ssc_endx) {
 		/* Load the PDC next pointer and counter registers */
 		prtd->period_ptr += prtd->period_size;
 		if (prtd->period_ptr >= prtd->dma_buffer_end)
 			prtd->period_ptr = prtd->dma_buffer;

 		ssc_writex(params->ssc->regs, params->pdc->xnpr,
 			   prtd->period_ptr);
 		ssc_writex(params->ssc->regs, params->pdc->xncr,
 			   prtd->period_size / params->pdc_xfer_size);
 	}

 	snd_pcm_period_elapsed(substream);
 }


 /*--------------------------------------------------------------------------*\
  * PCM operations
 \*--------------------------------------------------------------------------*/
 static int atmel_pcm_hw_params(struct snd_pcm_substream *substream,
 	struct snd_pcm_hw_params *params)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct atmel_runtime_data *prtd = runtime->private_data;
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;

 	/* this may get called several times by oss emulation
 	 * with different params */

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

 	prtd->params = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 	prtd->params->dma_intr_handler = atmel_pcm_dma_irq;

 	prtd->dma_buffer = runtime->dma_addr;
 	prtd->dma_buffer_end = runtime->dma_addr + runtime->dma_bytes;
 	prtd->period_size = params_period_bytes(params);

 	pr_debug("atmel-pcm: "
 		"hw_params: DMA for %s initialized "
 		"(dma_bytes=%zu, period_size=%zu)\n",
 		prtd->params->name,
 		runtime->dma_bytes,
 		prtd->period_size);
 	return 0;
 }

 static int atmel_pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	struct atmel_runtime_data *prtd = substream->runtime->private_data;
 	struct atmel_pcm_dma_params *params = prtd->params;

 	if (params != NULL) {
 		ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
 			   params->mask->pdc_disable);
 		prtd->params->dma_intr_handler = NULL;
 	}

 	return 0;
 }

 static int atmel_pcm_prepare(struct snd_pcm_substream *substream)
 {
 	struct atmel_runtime_data *prtd = substream->runtime->private_data;
 	struct atmel_pcm_dma_params *params = prtd->params;

 	ssc_writex(params->ssc->regs, SSC_IDR,
 		   params->mask->ssc_endx | params->mask->ssc_endbuf);
 	ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
 		   params->mask->pdc_disable);
 	return 0;
 }

 static int atmel_pcm_trigger(struct snd_pcm_substream *substream,
 	int cmd)
 {
 	struct snd_pcm_runtime *rtd = substream->runtime;
 	struct atmel_runtime_data *prtd = rtd->private_data;
 	struct atmel_pcm_dma_params *params = prtd->params;
 	int ret = 0;

 	pr_debug("atmel-pcm:buffer_size = %ld,"
 		"dma_area = %p, dma_bytes = %zu\n",
 		rtd->buffer_size, rtd->dma_area, rtd->dma_bytes);

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		prtd->period_ptr = prtd->dma_buffer;

 		ssc_writex(params->ssc->regs, params->pdc->xpr,
 			   prtd->period_ptr);
 		ssc_writex(params->ssc->regs, params->pdc->xcr,
 			   prtd->period_size / params->pdc_xfer_size);

 		prtd->period_ptr += prtd->period_size;
 		ssc_writex(params->ssc->regs, params->pdc->xnpr,
 			   prtd->period_ptr);
 		ssc_writex(params->ssc->regs, params->pdc->xncr,
 			   prtd->period_size / params->pdc_xfer_size);

 		pr_debug("atmel-pcm: trigger: "
 			"period_ptr=%lx, xpr=%u, "
 			"xcr=%u, xnpr=%u, xncr=%u\n",
 			(unsigned long)prtd->period_ptr,
 			ssc_readx(params->ssc->regs, params->pdc->xpr),
 			ssc_readx(params->ssc->regs, params->pdc->xcr),
 			ssc_readx(params->ssc->regs, params->pdc->xnpr),
 			ssc_readx(params->ssc->regs, params->pdc->xncr));

 		ssc_writex(params->ssc->regs, SSC_IER,
 			   params->mask->ssc_endx | params->mask->ssc_endbuf);
 		ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
 			   params->mask->pdc_enable);

 		pr_debug("sr=%u imr=%u\n",
 			ssc_readx(params->ssc->regs, SSC_SR),
 			ssc_readx(params->ssc->regs, SSC_IER));
 		break;		/* SNDRV_PCM_TRIGGER_START */

 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
 			   params->mask->pdc_disable);
 		break;

 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
 			   params->mask->pdc_enable);
 		break;

 	default:
 		ret = -EINVAL;
 	}

 	return ret;
 }

 static snd_pcm_uframes_t atmel_pcm_pointer(
 	struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct atmel_runtime_data *prtd = runtime->private_data;
 	struct atmel_pcm_dma_params *params = prtd->params;
 	dma_addr_t ptr;
 	snd_pcm_uframes_t x;

 	ptr = (dma_addr_t) ssc_readx(params->ssc->regs, params->pdc->xpr);
 	x = bytes_to_frames(runtime, ptr - prtd->dma_buffer);

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

 	return x;
 }

 static int atmel_pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct atmel_runtime_data *prtd;
 	int ret = 0;

 	snd_soc_set_runtime_hwparams(substream, &atmel_pcm_hardware);

 	/* ensure that buffer size is a multiple of period size */
 	ret = snd_pcm_hw_constraint_integer(runtime,
 						SNDRV_PCM_HW_PARAM_PERIODS);
 	if (ret < 0)
 		goto out;

 	prtd = kzalloc(sizeof(struct atmel_runtime_data), GFP_KERNEL);
 	if (prtd == NULL) {
 		ret = -ENOMEM;
 		goto out;
 	}
 	runtime->private_data = prtd;

  out:
 	return ret;
 }

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

 	kfree(prtd);
 	return 0;
 }

 static const struct snd_pcm_ops atmel_pcm_ops = {
 	.open		= atmel_pcm_open,
 	.close		= atmel_pcm_close,
 	.ioctl		= snd_pcm_lib_ioctl,
 	.hw_params	= atmel_pcm_hw_params,
 	.hw_free	= atmel_pcm_hw_free,
 	.prepare	= atmel_pcm_prepare,
 	.trigger	= atmel_pcm_trigger,
 	.pointer	= atmel_pcm_pointer,
 	.mmap		= atmel_pcm_mmap,
 };

 static struct snd_soc_component_driver atmel_soc_platform = {
 	.ops		= &atmel_pcm_ops,
 	.pcm_new	= atmel_pcm_new,
 	.pcm_free	= atmel_pcm_free,
 };

 int atmel_pcm_pdc_platform_register(struct device *dev)
 {
 	return devm_snd_soc_register_component(dev, &atmel_soc_platform,
 					       NULL, 0);
 }
 EXPORT_SYMBOL(atmel_pcm_pdc_platform_register);

 MODULE_AUTHOR("Sedji Gaouaou <sedji.gaouaou@atmel.com>");
 MODULE_DESCRIPTION("Atmel PCM module");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* atmel-pcm.c -- ALSA PCM interface for the Atmel atmel SoC.
	*
	* Copyright (C) 2005 SAN People
	* Copyright (C) 2008 Atmel
	*
	* Authors: Sedji Gaouaou <sedji.gaouaou@atmel.com>
	*
	* Based on at91-pcm. by:
	* Frank Mandarino <fmandarino@endrelia.com>
	* Copyright 2006 Endrelia Technologies Inc.
	*
	* Based on pxa2xx-pcm.c by:
	*
	* Author: Nicolas Pitre
	* Created: Nov 30, 2004
	* Copyright: (C) 2004 MontaVista Software, Inc.
	*/

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

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

	#include "atmel-pcm.h"


	static int atmel_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 = ATMEL_SSC_DMABUF_SIZE;

	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	buf->dev.dev = pcm->card->dev;
	buf->private_data = NULL;
	buf->area = dma_alloc_coherent(pcm->card->dev, size,
	&buf->addr, GFP_KERNEL);
	pr_debug("atmel-pcm: alloc dma buffer: area=%p, addr=%p, size=%zu\n",
	(void )buf->area, (void )(long)buf->addr, size);

	if (!buf->area)
	return -ENOMEM;

	buf->bytes = size;
	return 0;
	}

	static int atmel_pcm_mmap(struct snd_pcm_substream *substream,
	struct vm_area_struct *vma)
	{
	return remap_pfn_range(vma, vma->vm_start,
	substream->dma_buffer.addr >> PAGE_SHIFT,
	vma->vm_end - vma->vm_start, vma->vm_page_prot);
	}

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

	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
	if (ret)
	return ret;

	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
	pr_debug("atmel-pcm: allocating PCM playback DMA buffer\n");
	ret = atmel_pcm_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_PLAYBACK);
	if (ret)
	goto out;
	}

	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
	pr_debug("atmel-pcm: allocating PCM capture DMA buffer\n");
	ret = atmel_pcm_preallocate_dma_buffer(pcm,
	SNDRV_PCM_STREAM_CAPTURE);
	if (ret)
	goto out;
	}
	out:
	return ret;
	}

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

	/--------------------------------------------------------------------------\
	* Hardware definition
	\--------------------------------------------------------------------------/
	/* TODO: These values were taken from the AT91 platform driver, check
	* them against real values for AT32
	*/
	static const struct snd_pcm_hardware atmel_pcm_hardware = {
	.info = SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_PAUSE,
	.period_bytes_min = 32,
	.period_bytes_max = 8192,
	.periods_min = 2,
	.periods_max = 1024,
	.buffer_bytes_max = ATMEL_SSC_DMABUF_SIZE,
	};


	/--------------------------------------------------------------------------\
	* Data types
	\--------------------------------------------------------------------------/
	struct atmel_runtime_data {
	struct atmel_pcm_dma_params *params;
	dma_addr_t dma_buffer; /* physical address of dma buffer */
	dma_addr_t dma_buffer_end; /* first address beyond DMA buffer */
	size_t period_size;

	dma_addr_t period_ptr; /* physical address of next period */
	};

	/--------------------------------------------------------------------------\
	* ISR
	\--------------------------------------------------------------------------/
	static void atmel_pcm_dma_irq(u32 ssc_sr,
	struct snd_pcm_substream *substream)
	{
	struct atmel_runtime_data *prtd = substream->runtime->private_data;
	struct atmel_pcm_dma_params *params = prtd->params;
	static int count;

	count++;

	if (ssc_sr & params->mask->ssc_endbuf) {
	pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x, count=%d)\n",
	substream->stream == SNDRV_PCM_STREAM_PLAYBACK
	? "underrun" : "overrun",
	params->name, ssc_sr, count);

	/* re-start the PDC */
	ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
	params->mask->pdc_disable);
	prtd->period_ptr += prtd->period_size;
	if (prtd->period_ptr >= prtd->dma_buffer_end)
	prtd->period_ptr = prtd->dma_buffer;

	ssc_writex(params->ssc->regs, params->pdc->xpr,
	prtd->period_ptr);
	ssc_writex(params->ssc->regs, params->pdc->xcr,
	prtd->period_size / params->pdc_xfer_size);
	ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
	params->mask->pdc_enable);
	}

	if (ssc_sr & params->mask->ssc_endx) {
	/* Load the PDC next pointer and counter registers */
	prtd->period_ptr += prtd->period_size;
	if (prtd->period_ptr >= prtd->dma_buffer_end)
	prtd->period_ptr = prtd->dma_buffer;

	ssc_writex(params->ssc->regs, params->pdc->xnpr,
	prtd->period_ptr);
	ssc_writex(params->ssc->regs, params->pdc->xncr,
	prtd->period_size / params->pdc_xfer_size);
	}

	snd_pcm_period_elapsed(substream);
	}


	/--------------------------------------------------------------------------\
	* PCM operations
	\--------------------------------------------------------------------------/
	static int atmel_pcm_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct atmel_runtime_data *prtd = runtime->private_data;
	struct snd_soc_pcm_runtime *rtd = substream->private_data;

	/* this may get called several times by oss emulation
	* with different params */

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

	prtd->params = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
	prtd->params->dma_intr_handler = atmel_pcm_dma_irq;

	prtd->dma_buffer = runtime->dma_addr;
	prtd->dma_buffer_end = runtime->dma_addr + runtime->dma_bytes;
	prtd->period_size = params_period_bytes(params);

	pr_debug("atmel-pcm: "
	"hw_params: DMA for %s initialized "
	"(dma_bytes=%zu, period_size=%zu)\n",
	prtd->params->name,
	runtime->dma_bytes,
	prtd->period_size);
	return 0;
	}

	static int atmel_pcm_hw_free(struct snd_pcm_substream *substream)
	{
	struct atmel_runtime_data *prtd = substream->runtime->private_data;
	struct atmel_pcm_dma_params *params = prtd->params;

	if (params != NULL) {
	ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
	params->mask->pdc_disable);
	prtd->params->dma_intr_handler = NULL;
	}

	return 0;
	}

	static int atmel_pcm_prepare(struct snd_pcm_substream *substream)
	{
	struct atmel_runtime_data *prtd = substream->runtime->private_data;
	struct atmel_pcm_dma_params *params = prtd->params;

	ssc_writex(params->ssc->regs, SSC_IDR,
	params->mask->ssc_endx \| params->mask->ssc_endbuf);
	ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
	params->mask->pdc_disable);
	return 0;
	}

	static int atmel_pcm_trigger(struct snd_pcm_substream *substream,
	int cmd)
	{
	struct snd_pcm_runtime *rtd = substream->runtime;
	struct atmel_runtime_data *prtd = rtd->private_data;
	struct atmel_pcm_dma_params *params = prtd->params;
	int ret = 0;

	pr_debug("atmel-pcm:buffer_size = %ld,"
	"dma_area = %p, dma_bytes = %zu\n",
	rtd->buffer_size, rtd->dma_area, rtd->dma_bytes);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	prtd->period_ptr = prtd->dma_buffer;

	ssc_writex(params->ssc->regs, params->pdc->xpr,
	prtd->period_ptr);
	ssc_writex(params->ssc->regs, params->pdc->xcr,
	prtd->period_size / params->pdc_xfer_size);

	prtd->period_ptr += prtd->period_size;
	ssc_writex(params->ssc->regs, params->pdc->xnpr,
	prtd->period_ptr);
	ssc_writex(params->ssc->regs, params->pdc->xncr,
	prtd->period_size / params->pdc_xfer_size);

	pr_debug("atmel-pcm: trigger: "
	"period_ptr=%lx, xpr=%u, "
	"xcr=%u, xnpr=%u, xncr=%u\n",
	(unsigned long)prtd->period_ptr,
	ssc_readx(params->ssc->regs, params->pdc->xpr),
	ssc_readx(params->ssc->regs, params->pdc->xcr),
	ssc_readx(params->ssc->regs, params->pdc->xnpr),
	ssc_readx(params->ssc->regs, params->pdc->xncr));

	ssc_writex(params->ssc->regs, SSC_IER,
	params->mask->ssc_endx \| params->mask->ssc_endbuf);
	ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
	params->mask->pdc_enable);

	pr_debug("sr=%u imr=%u\n",
	ssc_readx(params->ssc->regs, SSC_SR),
	ssc_readx(params->ssc->regs, SSC_IER));
	break; /* SNDRV_PCM_TRIGGER_START */

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
	ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
	params->mask->pdc_disable);
	break;

	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
	ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
	params->mask->pdc_enable);
	break;

	default:
	ret = -EINVAL;
	}

	return ret;
	}

	static snd_pcm_uframes_t atmel_pcm_pointer(
	struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct atmel_runtime_data *prtd = runtime->private_data;
	struct atmel_pcm_dma_params *params = prtd->params;
	dma_addr_t ptr;
	snd_pcm_uframes_t x;

	ptr = (dma_addr_t) ssc_readx(params->ssc->regs, params->pdc->xpr);
	x = bytes_to_frames(runtime, ptr - prtd->dma_buffer);

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

	return x;
	}

	static int atmel_pcm_open(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct atmel_runtime_data *prtd;
	int ret = 0;

	snd_soc_set_runtime_hwparams(substream, &atmel_pcm_hardware);

	/* ensure that buffer size is a multiple of period size */
	ret = snd_pcm_hw_constraint_integer(runtime,
	SNDRV_PCM_HW_PARAM_PERIODS);
	if (ret < 0)
	goto out;

	prtd = kzalloc(sizeof(struct atmel_runtime_data), GFP_KERNEL);
	if (prtd == NULL) {
	ret = -ENOMEM;
	goto out;
	}
	runtime->private_data = prtd;

	out:
	return ret;
	}

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

	kfree(prtd);
	return 0;
	}

	static const struct snd_pcm_ops atmel_pcm_ops = {
	.open = atmel_pcm_open,
	.close = atmel_pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = atmel_pcm_hw_params,
	.hw_free = atmel_pcm_hw_free,
	.prepare = atmel_pcm_prepare,
	.trigger = atmel_pcm_trigger,
	.pointer = atmel_pcm_pointer,
	.mmap = atmel_pcm_mmap,
	};

	static struct snd_soc_component_driver atmel_soc_platform = {
	.ops = &atmel_pcm_ops,
	.pcm_new = atmel_pcm_new,
	.pcm_free = atmel_pcm_free,
	};

	int atmel_pcm_pdc_platform_register(struct device *dev)
	{
	return devm_snd_soc_register_component(dev, &atmel_soc_platform,
	NULL, 0);
	}
	EXPORT_SYMBOL(atmel_pcm_pdc_platform_register);

	MODULE_AUTHOR("Sedji Gaouaou <sedji.gaouaou@atmel.com>");
	MODULE_DESCRIPTION("Atmel PCM module");
	MODULE_LICENSE("GPL");