sound/soc/samsung/idma.c - kernel/quantenna - Git at Google

 /*
  * sound/soc/samsung/idma.c
  *
  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
  *		http://www.samsung.com
  *
  * I2S0's Internal DMA driver
  *
  * 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/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/soc.h>

 #include "i2s.h"
 #include "idma.h"
 #include "dma.h"
 #include "i2s-regs.h"

 #define ST_RUNNING		(1<<0)
 #define ST_OPENED		(1<<1)

 static const struct snd_pcm_hardware idma_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,
 	.buffer_bytes_max = MAX_IDMA_BUFFER,
 	.period_bytes_min = 128,
 	.period_bytes_max = MAX_IDMA_PERIOD,
 	.periods_min = 1,
 	.periods_max = 2,
 };

 struct idma_ctrl {
 	spinlock_t	lock;
 	int		state;
 	dma_addr_t	start;
 	dma_addr_t	pos;
 	dma_addr_t	end;
 	dma_addr_t	period;
 	dma_addr_t	periodsz;
 	void		*token;
 	void		(*cb)(void *dt, int bytes_xfer);
 };

 static struct idma_info {
 	spinlock_t	lock;
 	void		 __iomem  *regs;
 	dma_addr_t	lp_tx_addr;
 } idma;

 static int idma_irq;

 static void idma_getpos(dma_addr_t *src)
 {
 	*src = idma.lp_tx_addr +
 		(readl(idma.regs + I2STRNCNT) & 0xffffff) * 4;
 }

 static int idma_enqueue(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct idma_ctrl *prtd = substream->runtime->private_data;
 	u32 val;

 	spin_lock(&prtd->lock);
 	prtd->token = (void *) substream;
 	spin_unlock(&prtd->lock);

 	/* Internal DMA Level0 Interrupt Address */
 	val = idma.lp_tx_addr + prtd->periodsz;
 	writel(val, idma.regs + I2SLVL0ADDR);

 	/* Start address0 of I2S internal DMA operation. */
 	val = idma.lp_tx_addr;
 	writel(val, idma.regs + I2SSTR0);

 	/*
 	 * Transfer block size for I2S internal DMA.
 	 * Should decide transfer size before start dma operation
 	 */
 	val = readl(idma.regs + I2SSIZE);
 	val &= ~(I2SSIZE_TRNMSK << I2SSIZE_SHIFT);
 	val |= (((runtime->dma_bytes >> 2) &
 			I2SSIZE_TRNMSK) << I2SSIZE_SHIFT);
 	writel(val, idma.regs + I2SSIZE);

 	val = readl(idma.regs + I2SAHB);
 	val |= AHB_INTENLVL0;
 	writel(val, idma.regs + I2SAHB);

 	return 0;
 }

 static void idma_setcallbk(struct snd_pcm_substream *substream,
 				void (*cb)(void *, int))
 {
 	struct idma_ctrl *prtd = substream->runtime->private_data;

 	spin_lock(&prtd->lock);
 	prtd->cb = cb;
 	spin_unlock(&prtd->lock);
 }

 static void idma_control(int op)
 {
 	u32 val = readl(idma.regs + I2SAHB);

 	spin_lock(&idma.lock);

 	switch (op) {
 	case LPAM_DMA_START:
 		val |= (AHB_INTENLVL0 | AHB_DMAEN);
 		break;
 	case LPAM_DMA_STOP:
 		val &= ~(AHB_INTENLVL0 | AHB_DMAEN);
 		break;
 	default:
 		spin_unlock(&idma.lock);
 		return;
 	}

 	writel(val, idma.regs + I2SAHB);
 	spin_unlock(&idma.lock);
 }

 static void idma_done(void *id, int bytes_xfer)
 {
 	struct snd_pcm_substream *substream = id;
 	struct idma_ctrl *prtd = substream->runtime->private_data;

 	if (prtd && (prtd->state & ST_RUNNING))
 		snd_pcm_period_elapsed(substream);
 }

 static int idma_hw_params(struct snd_pcm_substream *substream,
 				struct snd_pcm_hw_params *params)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct idma_ctrl *prtd = substream->runtime->private_data;
 	u32 mod = readl(idma.regs + I2SMOD);
 	u32 ahb = readl(idma.regs + I2SAHB);

 	ahb |= (AHB_DMARLD | AHB_INTMASK);
 	mod |= MOD_TXS_IDMA;
 	writel(ahb, idma.regs + I2SAHB);
 	writel(mod, idma.regs + I2SMOD);

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

 	prtd->start = prtd->pos = runtime->dma_addr;
 	prtd->period = params_periods(params);
 	prtd->periodsz = params_period_bytes(params);
 	prtd->end = runtime->dma_addr + runtime->dma_bytes;

 	idma_setcallbk(substream, idma_done);

 	return 0;
 }

 static int idma_hw_free(struct snd_pcm_substream *substream)
 {
 	snd_pcm_set_runtime_buffer(substream, NULL);

 	return 0;
 }

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

 	prtd->pos = prtd->start;

 	/* flush the DMA channel */
 	idma_control(LPAM_DMA_STOP);
 	idma_enqueue(substream);

 	return 0;
 }

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

 	spin_lock(&prtd->lock);

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		prtd->state |= ST_RUNNING;
 		idma_control(LPAM_DMA_START);
 		break;

 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		prtd->state &= ~ST_RUNNING;
 		idma_control(LPAM_DMA_STOP);
 		break;

 	default:
 		ret = -EINVAL;
 		break;
 	}

 	spin_unlock(&prtd->lock);

 	return ret;
 }

 static snd_pcm_uframes_t
 	idma_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct idma_ctrl *prtd = runtime->private_data;
 	dma_addr_t src;
 	unsigned long res;

 	spin_lock(&prtd->lock);

 	idma_getpos(&src);
 	res = src - prtd->start;

 	spin_unlock(&prtd->lock);

 	return bytes_to_frames(substream->runtime, res);
 }

 static int idma_mmap(struct snd_pcm_substream *substream,
 	struct vm_area_struct *vma)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	unsigned long size, offset;
 	int ret;

 	/* From snd_pcm_lib_mmap_iomem */
 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	size = vma->vm_end - vma->vm_start;
 	offset = vma->vm_pgoff << PAGE_SHIFT;
 	ret = io_remap_pfn_range(vma, vma->vm_start,
 			(runtime->dma_addr + offset) >> PAGE_SHIFT,
 			size, vma->vm_page_prot);

 	return ret;
 }

 static irqreturn_t iis_irq(int irqno, void *dev_id)
 {
 	struct idma_ctrl *prtd = (struct idma_ctrl *)dev_id;
 	u32 iisahb, val, addr;

 	iisahb  = readl(idma.regs + I2SAHB);

 	val = (iisahb & AHB_LVL0INT) ? AHB_CLRLVL0INT : 0;

 	if (val) {
 		iisahb |= val;
 		writel(iisahb, idma.regs + I2SAHB);

 		addr = readl(idma.regs + I2SLVL0ADDR) - idma.lp_tx_addr;
 		addr += prtd->periodsz;
 		addr %= (u32)(prtd->end - prtd->start);
 		addr += idma.lp_tx_addr;

 		writel(addr, idma.regs + I2SLVL0ADDR);

 		if (prtd->cb)
 			prtd->cb(prtd->token, prtd->period);
 	}

 	return IRQ_HANDLED;
 }

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

 	snd_soc_set_runtime_hwparams(substream, &idma_hardware);

 	prtd = kzalloc(sizeof(struct idma_ctrl), GFP_KERNEL);
 	if (prtd == NULL)
 		return -ENOMEM;

 	ret = request_irq(idma_irq, iis_irq, 0, "i2s", prtd);
 	if (ret < 0) {
 		pr_err("fail to claim i2s irq , ret = %d\n", ret);
 		kfree(prtd);
 		return ret;
 	}

 	spin_lock_init(&prtd->lock);

 	runtime->private_data = prtd;

 	return 0;
 }

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

 	free_irq(idma_irq, prtd);

 	if (!prtd)
 		pr_err("idma_close called with prtd == NULL\n");

 	kfree(prtd);

 	return 0;
 }

 static struct snd_pcm_ops idma_ops = {
 	.open		= idma_open,
 	.close		= idma_close,
 	.ioctl		= snd_pcm_lib_ioctl,
 	.trigger	= idma_trigger,
 	.pointer	= idma_pointer,
 	.mmap		= idma_mmap,
 	.hw_params	= idma_hw_params,
 	.hw_free	= idma_hw_free,
 	.prepare	= idma_prepare,
 };

 static void idma_free(struct snd_pcm *pcm)
 {
 	struct snd_pcm_substream *substream;
 	struct snd_dma_buffer *buf;

 	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
 	if (!substream)
 		return;

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

 	iounmap((void __iomem *)buf->area);

 	buf->area = NULL;
 	buf->addr = 0;
 }

 static int preallocate_idma_buffer(struct snd_pcm *pcm, int stream)
 {
 	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
 	struct snd_dma_buffer *buf = &substream->dma_buffer;

 	buf->dev.dev = pcm->card->dev;
 	buf->private_data = NULL;

 	/* Assign PCM buffer pointers */
 	buf->dev.type = SNDRV_DMA_TYPE_CONTINUOUS;
 	buf->addr = idma.lp_tx_addr;
 	buf->bytes = idma_hardware.buffer_bytes_max;
 	buf->area = (unsigned char * __force)ioremap(buf->addr, buf->bytes);

 	return 0;
 }

 static int idma_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) {
 		ret = preallocate_idma_buffer(pcm,
 				SNDRV_PCM_STREAM_PLAYBACK);
 	}

 	return ret;
 }

 void idma_reg_addr_init(void __iomem *regs, dma_addr_t addr)
 {
 	spin_lock_init(&idma.lock);
 	idma.regs = regs;
 	idma.lp_tx_addr = addr;
 }
 EXPORT_SYMBOL_GPL(idma_reg_addr_init);

 static struct snd_soc_platform_driver asoc_idma_platform = {
 	.ops = &idma_ops,
 	.pcm_new = idma_new,
 	.pcm_free = idma_free,
 };

 static int asoc_idma_platform_probe(struct platform_device *pdev)
 {
 	idma_irq = platform_get_irq(pdev, 0);
 	if (idma_irq < 0)
 		return idma_irq;

 	return devm_snd_soc_register_platform(&pdev->dev, &asoc_idma_platform);
 }

 static struct platform_driver asoc_idma_driver = {
 	.driver = {
 		.name = "samsung-idma",
 	},

 	.probe = asoc_idma_platform_probe,
 };

 module_platform_driver(asoc_idma_driver);

 MODULE_AUTHOR("Jaswinder Singh, <jassisinghbrar@gmail.com>");
 MODULE_DESCRIPTION("Samsung ASoC IDMA Driver");
 MODULE_LICENSE("GPL");
	/*
	* sound/soc/samsung/idma.c
	*
	* Copyright (c) 2011 Samsung Electronics Co., Ltd.
	* http://www.samsung.com
	*
	* I2S0's Internal DMA driver
	*
	* 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/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/dma-mapping.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>
	#include <sound/soc.h>

	#include "i2s.h"
	#include "idma.h"
	#include "dma.h"
	#include "i2s-regs.h"

	#define ST_RUNNING (1<<0)
	#define ST_OPENED (1<<1)

	static const struct snd_pcm_hardware idma_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,
	.buffer_bytes_max = MAX_IDMA_BUFFER,
	.period_bytes_min = 128,
	.period_bytes_max = MAX_IDMA_PERIOD,
	.periods_min = 1,
	.periods_max = 2,
	};

	struct idma_ctrl {
	spinlock_t lock;
	int state;
	dma_addr_t start;
	dma_addr_t pos;
	dma_addr_t end;
	dma_addr_t period;
	dma_addr_t periodsz;
	void *token;
	void (cb)(void dt, int bytes_xfer);
	};

	static struct idma_info {
	spinlock_t lock;
	void __iomem *regs;
	dma_addr_t lp_tx_addr;
	} idma;

	static int idma_irq;

	static void idma_getpos(dma_addr_t *src)
	{
	*src = idma.lp_tx_addr +
	(readl(idma.regs + I2STRNCNT) & 0xffffff) * 4;
	}

	static int idma_enqueue(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = substream->runtime->private_data;
	u32 val;

	spin_lock(&prtd->lock);
	prtd->token = (void *) substream;
	spin_unlock(&prtd->lock);

	/* Internal DMA Level0 Interrupt Address */
	val = idma.lp_tx_addr + prtd->periodsz;
	writel(val, idma.regs + I2SLVL0ADDR);

	/* Start address0 of I2S internal DMA operation. */
	val = idma.lp_tx_addr;
	writel(val, idma.regs + I2SSTR0);

	/*
	* Transfer block size for I2S internal DMA.
	* Should decide transfer size before start dma operation
	*/
	val = readl(idma.regs + I2SSIZE);
	val &= ~(I2SSIZE_TRNMSK << I2SSIZE_SHIFT);
	val \|= (((runtime->dma_bytes >> 2) &
	I2SSIZE_TRNMSK) << I2SSIZE_SHIFT);
	writel(val, idma.regs + I2SSIZE);

	val = readl(idma.regs + I2SAHB);
	val \|= AHB_INTENLVL0;
	writel(val, idma.regs + I2SAHB);

	return 0;
	}

	static void idma_setcallbk(struct snd_pcm_substream *substream,
	void (cb)(void , int))
	{
	struct idma_ctrl *prtd = substream->runtime->private_data;

	spin_lock(&prtd->lock);
	prtd->cb = cb;
	spin_unlock(&prtd->lock);
	}

	static void idma_control(int op)
	{
	u32 val = readl(idma.regs + I2SAHB);

	spin_lock(&idma.lock);

	switch (op) {
	case LPAM_DMA_START:
	val \|= (AHB_INTENLVL0 \| AHB_DMAEN);
	break;
	case LPAM_DMA_STOP:
	val &= ~(AHB_INTENLVL0 \| AHB_DMAEN);
	break;
	default:
	spin_unlock(&idma.lock);
	return;
	}

	writel(val, idma.regs + I2SAHB);
	spin_unlock(&idma.lock);
	}

	static void idma_done(void *id, int bytes_xfer)
	{
	struct snd_pcm_substream *substream = id;
	struct idma_ctrl *prtd = substream->runtime->private_data;

	if (prtd && (prtd->state & ST_RUNNING))
	snd_pcm_period_elapsed(substream);
	}

	static int idma_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = substream->runtime->private_data;
	u32 mod = readl(idma.regs + I2SMOD);
	u32 ahb = readl(idma.regs + I2SAHB);

	ahb \|= (AHB_DMARLD \| AHB_INTMASK);
	mod \|= MOD_TXS_IDMA;
	writel(ahb, idma.regs + I2SAHB);
	writel(mod, idma.regs + I2SMOD);

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

	prtd->start = prtd->pos = runtime->dma_addr;
	prtd->period = params_periods(params);
	prtd->periodsz = params_period_bytes(params);
	prtd->end = runtime->dma_addr + runtime->dma_bytes;

	idma_setcallbk(substream, idma_done);

	return 0;
	}

	static int idma_hw_free(struct snd_pcm_substream *substream)
	{
	snd_pcm_set_runtime_buffer(substream, NULL);

	return 0;
	}

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

	prtd->pos = prtd->start;

	/* flush the DMA channel */
	idma_control(LPAM_DMA_STOP);
	idma_enqueue(substream);

	return 0;
	}

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

	spin_lock(&prtd->lock);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
	prtd->state \|= ST_RUNNING;
	idma_control(LPAM_DMA_START);
	break;

	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
	prtd->state &= ~ST_RUNNING;
	idma_control(LPAM_DMA_STOP);
	break;

	default:
	ret = -EINVAL;
	break;
	}

	spin_unlock(&prtd->lock);

	return ret;
	}

	static snd_pcm_uframes_t
	idma_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = runtime->private_data;
	dma_addr_t src;
	unsigned long res;

	spin_lock(&prtd->lock);

	idma_getpos(&src);
	res = src - prtd->start;

	spin_unlock(&prtd->lock);

	return bytes_to_frames(substream->runtime, res);
	}

	static int idma_mmap(struct snd_pcm_substream *substream,
	struct vm_area_struct *vma)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	unsigned long size, offset;
	int ret;

	/* From snd_pcm_lib_mmap_iomem */
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	size = vma->vm_end - vma->vm_start;
	offset = vma->vm_pgoff << PAGE_SHIFT;
	ret = io_remap_pfn_range(vma, vma->vm_start,
	(runtime->dma_addr + offset) >> PAGE_SHIFT,
	size, vma->vm_page_prot);

	return ret;
	}

	static irqreturn_t iis_irq(int irqno, void *dev_id)
	{
	struct idma_ctrl prtd = (struct idma_ctrl )dev_id;
	u32 iisahb, val, addr;

	iisahb = readl(idma.regs + I2SAHB);

	val = (iisahb & AHB_LVL0INT) ? AHB_CLRLVL0INT : 0;

	if (val) {
	iisahb \|= val;
	writel(iisahb, idma.regs + I2SAHB);

	addr = readl(idma.regs + I2SLVL0ADDR) - idma.lp_tx_addr;
	addr += prtd->periodsz;
	addr %= (u32)(prtd->end - prtd->start);
	addr += idma.lp_tx_addr;

	writel(addr, idma.regs + I2SLVL0ADDR);

	if (prtd->cb)
	prtd->cb(prtd->token, prtd->period);
	}

	return IRQ_HANDLED;
	}

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

	snd_soc_set_runtime_hwparams(substream, &idma_hardware);

	prtd = kzalloc(sizeof(struct idma_ctrl), GFP_KERNEL);
	if (prtd == NULL)
	return -ENOMEM;

	ret = request_irq(idma_irq, iis_irq, 0, "i2s", prtd);
	if (ret < 0) {
	pr_err("fail to claim i2s irq , ret = %d\n", ret);
	kfree(prtd);
	return ret;
	}

	spin_lock_init(&prtd->lock);

	runtime->private_data = prtd;

	return 0;
	}

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

	free_irq(idma_irq, prtd);

	if (!prtd)
	pr_err("idma_close called with prtd == NULL\n");

	kfree(prtd);

	return 0;
	}

	static struct snd_pcm_ops idma_ops = {
	.open = idma_open,
	.close = idma_close,
	.ioctl = snd_pcm_lib_ioctl,
	.trigger = idma_trigger,
	.pointer = idma_pointer,
	.mmap = idma_mmap,
	.hw_params = idma_hw_params,
	.hw_free = idma_hw_free,
	.prepare = idma_prepare,
	};

	static void idma_free(struct snd_pcm *pcm)
	{
	struct snd_pcm_substream *substream;
	struct snd_dma_buffer *buf;

	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
	if (!substream)
	return;

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

	iounmap((void __iomem *)buf->area);

	buf->area = NULL;
	buf->addr = 0;
	}

	static int preallocate_idma_buffer(struct snd_pcm *pcm, int stream)
	{
	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
	struct snd_dma_buffer *buf = &substream->dma_buffer;

	buf->dev.dev = pcm->card->dev;
	buf->private_data = NULL;

	/* Assign PCM buffer pointers */
	buf->dev.type = SNDRV_DMA_TYPE_CONTINUOUS;
	buf->addr = idma.lp_tx_addr;
	buf->bytes = idma_hardware.buffer_bytes_max;
	buf->area = (unsigned char * __force)ioremap(buf->addr, buf->bytes);

	return 0;
	}

	static int idma_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) {
	ret = preallocate_idma_buffer(pcm,
	SNDRV_PCM_STREAM_PLAYBACK);
	}

	return ret;
	}

	void idma_reg_addr_init(void __iomem *regs, dma_addr_t addr)
	{
	spin_lock_init(&idma.lock);
	idma.regs = regs;
	idma.lp_tx_addr = addr;
	}
	EXPORT_SYMBOL_GPL(idma_reg_addr_init);

	static struct snd_soc_platform_driver asoc_idma_platform = {
	.ops = &idma_ops,
	.pcm_new = idma_new,
	.pcm_free = idma_free,
	};

	static int asoc_idma_platform_probe(struct platform_device *pdev)
	{
	idma_irq = platform_get_irq(pdev, 0);
	if (idma_irq < 0)
	return idma_irq;

	return devm_snd_soc_register_platform(&pdev->dev, &asoc_idma_platform);
	}

	static struct platform_driver asoc_idma_driver = {
	.driver = {
	.name = "samsung-idma",
	},

	.probe = asoc_idma_platform_probe,
	};

	module_platform_driver(asoc_idma_driver);

	MODULE_AUTHOR("Jaswinder Singh, <jassisinghbrar@gmail.com>");
	MODULE_DESCRIPTION("Samsung ASoC IDMA Driver");
	MODULE_LICENSE("GPL");