[deliverable/linux.git] / sound / soc / samsung / dma.c

/*
 * dma.c  --  ALSA Soc Audio Layer
 *
 * (c) 2006 Wolfson Microelectronics PLC.
 * Graeme Gregory graeme.gregory@wolfsonmicro.com or linux@wolfsonmicro.com
 *
 * Copyright 2004-2005 Simtec Electronics
 *	http://armlinux.simtec.co.uk/
 *	Ben Dooks <ben@simtec.co.uk>
 *
 *  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/slab.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>

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

#include <asm/dma.h>
#include <mach/hardware.h>
#include <mach/dma.h>

#include "dma.h"

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

static const struct snd_pcm_hardware dma_hardware = {
	.info			= SNDRV_PCM_INFO_INTERLEAVED |
				    SNDRV_PCM_INFO_BLOCK_TRANSFER |
				    SNDRV_PCM_INFO_MMAP |
				    SNDRV_PCM_INFO_MMAP_VALID,
	.buffer_bytes_max	= 128*1024,
	.period_bytes_min	= PAGE_SIZE,
	.period_bytes_max	= PAGE_SIZE*2,
	.periods_min		= 2,
	.periods_max		= 128,
	.fifo_size		= 32,
};

struct runtime_data {
	spinlock_t lock;
	int state;
	unsigned int dma_loaded;
	unsigned int dma_period;
	dma_addr_t dma_start;
	dma_addr_t dma_pos;
	dma_addr_t dma_end;
	struct s3c_dma_params *params;
};

static void audio_buffdone(void *data);

/* dma_enqueue
 *
 * place a dma buffer onto the queue for the dma system
 * to handle.
 */
static void dma_enqueue(struct snd_pcm_substream *substream)
{
	struct runtime_data *prtd = substream->runtime->private_data;
	dma_addr_t pos = prtd->dma_pos;
	unsigned int limit;
	struct samsung_dma_prep dma_info;

	pr_debug("Entered %s\n", __func__);

	limit = (prtd->dma_end - prtd->dma_start) / prtd->dma_period;

	pr_debug("%s: loaded %d, limit %d\n",
				__func__, prtd->dma_loaded, limit);

	dma_info.cap = (samsung_dma_has_circular() ? DMA_CYCLIC : DMA_SLAVE);
	dma_info.direction =
		(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
		? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
	dma_info.fp = audio_buffdone;
	dma_info.fp_param = substream;
	dma_info.period = prtd->dma_period;
	dma_info.len = prtd->dma_period*limit;

	if (dma_info.cap == DMA_CYCLIC) {
		dma_info.buf = pos;
		prtd->params->ops->prepare(prtd->params->ch, &dma_info);
		prtd->dma_loaded += limit;
		return;
	}

	while (prtd->dma_loaded < limit) {
		pr_debug("dma_loaded: %d\n", prtd->dma_loaded);

		if ((pos + dma_info.period) > prtd->dma_end) {
			dma_info.period  = prtd->dma_end - pos;
			pr_debug("%s: corrected dma len %ld\n",
					__func__, dma_info.period);
		}

		dma_info.buf = pos;
		prtd->params->ops->prepare(prtd->params->ch, &dma_info);

		prtd->dma_loaded++;
		pos += prtd->dma_period;
		if (pos >= prtd->dma_end)
			pos = prtd->dma_start;
	}

	prtd->dma_pos = pos;
}

static void audio_buffdone(void *data)
{
	struct snd_pcm_substream *substream = data;
	struct runtime_data *prtd = substream->runtime->private_data;

	pr_debug("Entered %s\n", __func__);

	if (prtd->state & ST_RUNNING) {
		prtd->dma_pos += prtd->dma_period;
		if (prtd->dma_pos >= prtd->dma_end)
			prtd->dma_pos = prtd->dma_start;

		if (substream)
			snd_pcm_period_elapsed(substream);

		spin_lock(&prtd->lock);
		if (!samsung_dma_has_circular()) {
			prtd->dma_loaded--;
			dma_enqueue(substream);
		}
		spin_unlock(&prtd->lock);
	}
}

static int dma_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct runtime_data *prtd = runtime->private_data;
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	unsigned long totbytes = params_buffer_bytes(params);
	struct s3c_dma_params *dma =
		snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
	struct samsung_dma_req req;
	struct samsung_dma_config config;

	pr_debug("Entered %s\n", __func__);

	/* 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 -HW */
	if (prtd->params == NULL) {
		/* prepare DMA */
		prtd->params = dma;

		pr_debug("params %p, client %p, channel %d\n", prtd->params,
			prtd->params->client, prtd->params->channel);

		prtd->params->ops = samsung_dma_get_ops();

		req.cap = (samsung_dma_has_circular() ?
			DMA_CYCLIC : DMA_SLAVE);
		req.client = prtd->params->client;
		config.direction =
			(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
			? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
		config.width = prtd->params->dma_size;
		config.fifo = prtd->params->dma_addr;
		prtd->params->ch = prtd->params->ops->request(
				prtd->params->channel, &req, rtd->cpu_dai->dev,
				prtd->params->ch_name);
		if (!prtd->params->ch) {
			pr_err("Failed to allocate DMA channel\n");
			return -ENXIO;
		}
		prtd->params->ops->config(prtd->params->ch, &config);
	}

	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

	runtime->dma_bytes = totbytes;

	spin_lock_irq(&prtd->lock);
	prtd->dma_loaded = 0;
	prtd->dma_period = params_period_bytes(params);
	prtd->dma_start = runtime->dma_addr;
	prtd->dma_pos = prtd->dma_start;
	prtd->dma_end = prtd->dma_start + totbytes;
	spin_unlock_irq(&prtd->lock);

	return 0;
}

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

	pr_debug("Entered %s\n", __func__);

	snd_pcm_set_runtime_buffer(substream, NULL);

	if (prtd->params) {
		prtd->params->ops->flush(prtd->params->ch);
		prtd->params->ops->release(prtd->params->ch,
					prtd->params->client);
		prtd->params = NULL;
	}

	return 0;
}

static int dma_prepare(struct snd_pcm_substream *substream)
{
	struct runtime_data *prtd = substream->runtime->private_data;
	int ret = 0;

	pr_debug("Entered %s\n", __func__);

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

	/* flush the DMA channel */
	prtd->params->ops->flush(prtd->params->ch);

	prtd->dma_loaded = 0;
	prtd->dma_pos = prtd->dma_start;

	/* enqueue dma buffers */
	dma_enqueue(substream);

	return ret;
}

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

	pr_debug("Entered %s\n", __func__);

	spin_lock(&prtd->lock);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		prtd->state |= ST_RUNNING;
		prtd->params->ops->trigger(prtd->params->ch);
		break;

	case SNDRV_PCM_TRIGGER_STOP:
		prtd->state &= ~ST_RUNNING;
		prtd->params->ops->stop(prtd->params->ch);
		break;

	default:
		ret = -EINVAL;
		break;
	}

	spin_unlock(&prtd->lock);

	return ret;
}

static snd_pcm_uframes_t
dma_pointer(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct runtime_data *prtd = runtime->private_data;
	unsigned long res;

	pr_debug("Entered %s\n", __func__);

	res = prtd->dma_pos - prtd->dma_start;

	pr_debug("Pointer offset: %lu\n", res);

	/* we seem to be getting the odd error from the pcm library due
	 * to out-of-bounds pointers. this is maybe due to the dma engine
	 * not having loaded the new values for the channel before being
	 * called... (todo - fix )
	 */

	if (res >= snd_pcm_lib_buffer_bytes(substream)) {
		if (res == snd_pcm_lib_buffer_bytes(substream))
			res = 0;
	}

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

static int dma_open(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct runtime_data *prtd;

	pr_debug("Entered %s\n", __func__);

	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	snd_soc_set_runtime_hwparams(substream, &dma_hardware);

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

	spin_lock_init(&prtd->lock);

	runtime->private_data = prtd;
	return 0;
}

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

	pr_debug("Entered %s\n", __func__);

	if (!prtd)
		pr_debug("dma_close called with prtd == NULL\n");

	kfree(prtd);

	return 0;
}

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

	pr_debug("Entered %s\n", __func__);

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

static struct snd_pcm_ops dma_ops = {
	.open		= dma_open,
	.close		= dma_close,
	.ioctl		= snd_pcm_lib_ioctl,
	.hw_params	= dma_hw_params,
	.hw_free	= dma_hw_free,
	.prepare	= dma_prepare,
	.trigger	= dma_trigger,
	.pointer	= dma_pointer,
	.mmap		= dma_mmap,
};

static int 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 = dma_hardware.buffer_bytes_max;

	pr_debug("Entered %s\n", __func__);

	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 dma_free_dma_buffers(struct snd_pcm *pcm)
{
	struct snd_pcm_substream *substream;
	struct snd_dma_buffer *buf;
	int stream;

	pr_debug("Entered %s\n", __func__);

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

	pr_debug("Entered %s\n", __func__);

	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_dma_buffer(pcm,
			SNDRV_PCM_STREAM_PLAYBACK);
		if (ret)
			goto out;
	}

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

static struct snd_soc_platform_driver samsung_asoc_platform = {
	.ops		= &dma_ops,
	.pcm_new	= dma_new,
	.pcm_free	= dma_free_dma_buffers,
};

void samsung_asoc_init_dma_data(struct snd_soc_dai *dai,
				struct s3c_dma_params *playback,
				struct s3c_dma_params *capture)
{
	snd_soc_dai_init_dma_data(dai, playback, capture);
}
EXPORT_SYMBOL_GPL(samsung_asoc_init_dma_data);

int samsung_asoc_dma_platform_register(struct device *dev)
{
	return devm_snd_soc_register_platform(dev, &samsung_asoc_platform);
}
EXPORT_SYMBOL_GPL(samsung_asoc_dma_platform_register);

MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_DESCRIPTION("Samsung ASoC DMA Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
	1	/*
	2	* dma.c -- ALSA Soc Audio Layer
	3	*
	4	* (c) 2006 Wolfson Microelectronics PLC.
	5	* Graeme Gregory graeme.gregory@wolfsonmicro.com or linux@wolfsonmicro.com
	6	*
	7	* Copyright 2004-2005 Simtec Electronics
	8	* http://armlinux.simtec.co.uk/
	9	* Ben Dooks <ben@simtec.co.uk>
	10	*
	11	* This program is free software; you can redistribute it and/or modify it
	12	* under the terms of the GNU General Public License as published by the
	13	* Free Software Foundation; either version 2 of the License, or (at your
	14	* option) any later version.
	15	*/
	16
	17	#include <linux/slab.h>
	18	#include <linux/dma-mapping.h>
	19	#include <linux/module.h>
	20
	21	#include <sound/soc.h>
	22	#include <sound/pcm_params.h>
	23
	24	#include <asm/dma.h>
	25	#include <mach/hardware.h>
	26	#include <mach/dma.h>
	27
	28	#include "dma.h"
	29
	30	#define ST_RUNNING (1<<0)
	31	#define ST_OPENED (1<<1)
	32
	33	static const struct snd_pcm_hardware dma_hardware = {
	34	.info = SNDRV_PCM_INFO_INTERLEAVED \|
	35	SNDRV_PCM_INFO_BLOCK_TRANSFER \|
	36	SNDRV_PCM_INFO_MMAP \|
	37	SNDRV_PCM_INFO_MMAP_VALID,
	38	.buffer_bytes_max = 128*1024,
	39	.period_bytes_min = PAGE_SIZE,
	40	.period_bytes_max = PAGE_SIZE*2,
	41	.periods_min = 2,
	42	.periods_max = 128,
	43	.fifo_size = 32,
	44	};
	45
	46	struct runtime_data {
	47	spinlock_t lock;
	48	int state;
	49	unsigned int dma_loaded;
	50	unsigned int dma_period;
	51	dma_addr_t dma_start;
	52	dma_addr_t dma_pos;
	53	dma_addr_t dma_end;
	54	struct s3c_dma_params *params;
	55	};
	56
	57	static void audio_buffdone(void *data);
	58
	59	/* dma_enqueue
	60	*
	61	* place a dma buffer onto the queue for the dma system
	62	* to handle.
	63	*/
	64	static void dma_enqueue(struct snd_pcm_substream *substream)
	65	{
	66	struct runtime_data *prtd = substream->runtime->private_data;
	67	dma_addr_t pos = prtd->dma_pos;
	68	unsigned int limit;
	69	struct samsung_dma_prep dma_info;
	70
	71	pr_debug("Entered %s\n", __func__);
	72
	73	limit = (prtd->dma_end - prtd->dma_start) / prtd->dma_period;
	74
	75	pr_debug("%s: loaded %d, limit %d\n",
	76	__func__, prtd->dma_loaded, limit);
	77
	78	dma_info.cap = (samsung_dma_has_circular() ? DMA_CYCLIC : DMA_SLAVE);
	79	dma_info.direction =
	80	(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
	81	? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
	82	dma_info.fp = audio_buffdone;
	83	dma_info.fp_param = substream;
	84	dma_info.period = prtd->dma_period;
	85	dma_info.len = prtd->dma_period*limit;
	86
	87	if (dma_info.cap == DMA_CYCLIC) {
	88	dma_info.buf = pos;
	89	prtd->params->ops->prepare(prtd->params->ch, &dma_info);
	90	prtd->dma_loaded += limit;
	91	return;
	92	}
	93
	94	while (prtd->dma_loaded < limit) {
	95	pr_debug("dma_loaded: %d\n", prtd->dma_loaded);
	96
	97	if ((pos + dma_info.period) > prtd->dma_end) {
	98	dma_info.period = prtd->dma_end - pos;
	99	pr_debug("%s: corrected dma len %ld\n",
	100	__func__, dma_info.period);
	101	}
	102
	103	dma_info.buf = pos;
	104	prtd->params->ops->prepare(prtd->params->ch, &dma_info);
	105
	106	prtd->dma_loaded++;
	107	pos += prtd->dma_period;
	108	if (pos >= prtd->dma_end)
	109	pos = prtd->dma_start;
	110	}
	111
	112	prtd->dma_pos = pos;
	113	}
	114
	115	static void audio_buffdone(void *data)
	116	{
	117	struct snd_pcm_substream *substream = data;
	118	struct runtime_data *prtd = substream->runtime->private_data;
	119
	120	pr_debug("Entered %s\n", __func__);
	121
	122	if (prtd->state & ST_RUNNING) {
	123	prtd->dma_pos += prtd->dma_period;
	124	if (prtd->dma_pos >= prtd->dma_end)
	125	prtd->dma_pos = prtd->dma_start;
	126
	127	if (substream)
	128	snd_pcm_period_elapsed(substream);
	129
	130	spin_lock(&prtd->lock);
	131	if (!samsung_dma_has_circular()) {
	132	prtd->dma_loaded--;
	133	dma_enqueue(substream);
	134	}
	135	spin_unlock(&prtd->lock);
	136	}
	137	}
	138
	139	static int dma_hw_params(struct snd_pcm_substream *substream,
	140	struct snd_pcm_hw_params *params)
	141	{
	142	struct snd_pcm_runtime *runtime = substream->runtime;
	143	struct runtime_data *prtd = runtime->private_data;
	144	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	145	unsigned long totbytes = params_buffer_bytes(params);
	146	struct s3c_dma_params *dma =
	147	snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
	148	struct samsung_dma_req req;
	149	struct samsung_dma_config config;
	150
	151	pr_debug("Entered %s\n", __func__);
	152
	153	/* return if this is a bufferless transfer e.g.
	154	* codec <--> BT codec or GSM modem -- lg FIXME */
	155	if (!dma)
	156	return 0;
	157
	158	/* this may get called several times by oss emulation
	159	* with different params -HW */
	160	if (prtd->params == NULL) {
	161	/* prepare DMA */
	162	prtd->params = dma;
	163
	164	pr_debug("params %p, client %p, channel %d\n", prtd->params,
	165	prtd->params->client, prtd->params->channel);
	166
	167	prtd->params->ops = samsung_dma_get_ops();
	168
	169	req.cap = (samsung_dma_has_circular() ?
	170	DMA_CYCLIC : DMA_SLAVE);
	171	req.client = prtd->params->client;
	172	config.direction =
	173	(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
	174	? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
	175	config.width = prtd->params->dma_size;
	176	config.fifo = prtd->params->dma_addr;
	177	prtd->params->ch = prtd->params->ops->request(
	178	prtd->params->channel, &req, rtd->cpu_dai->dev,
	179	prtd->params->ch_name);
	180	if (!prtd->params->ch) {
	181	pr_err("Failed to allocate DMA channel\n");
	182	return -ENXIO;
	183	}
	184	prtd->params->ops->config(prtd->params->ch, &config);
	185	}
	186
	187	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
	188
	189	runtime->dma_bytes = totbytes;
	190
	191	spin_lock_irq(&prtd->lock);
	192	prtd->dma_loaded = 0;
	193	prtd->dma_period = params_period_bytes(params);
	194	prtd->dma_start = runtime->dma_addr;
	195	prtd->dma_pos = prtd->dma_start;
	196	prtd->dma_end = prtd->dma_start + totbytes;
	197	spin_unlock_irq(&prtd->lock);
	198
	199	return 0;
	200	}
	201
	202	static int dma_hw_free(struct snd_pcm_substream *substream)
	203	{
	204	struct runtime_data *prtd = substream->runtime->private_data;
	205
	206	pr_debug("Entered %s\n", __func__);
	207
	208	snd_pcm_set_runtime_buffer(substream, NULL);
	209
	210	if (prtd->params) {
	211	prtd->params->ops->flush(prtd->params->ch);
	212	prtd->params->ops->release(prtd->params->ch,
	213	prtd->params->client);
	214	prtd->params = NULL;
	215	}
	216
	217	return 0;
	218	}
	219
	220	static int dma_prepare(struct snd_pcm_substream *substream)
	221	{
	222	struct runtime_data *prtd = substream->runtime->private_data;
	223	int ret = 0;
	224
	225	pr_debug("Entered %s\n", __func__);
	226
	227	/* return if this is a bufferless transfer e.g.
	228	* codec <--> BT codec or GSM modem -- lg FIXME */
	229	if (!prtd->params)
	230	return 0;
	231
	232	/* flush the DMA channel */
	233	prtd->params->ops->flush(prtd->params->ch);
	234
	235	prtd->dma_loaded = 0;
	236	prtd->dma_pos = prtd->dma_start;
	237
	238	/* enqueue dma buffers */
	239	dma_enqueue(substream);
	240
	241	return ret;
	242	}
	243
	244	static int dma_trigger(struct snd_pcm_substream *substream, int cmd)
	245	{
	246	struct runtime_data *prtd = substream->runtime->private_data;
	247	int ret = 0;
	248
	249	pr_debug("Entered %s\n", __func__);
	250
	251	spin_lock(&prtd->lock);
	252
	253	switch (cmd) {
	254	case SNDRV_PCM_TRIGGER_START:
	255	prtd->state \|= ST_RUNNING;
	256	prtd->params->ops->trigger(prtd->params->ch);
	257	break;
	258
	259	case SNDRV_PCM_TRIGGER_STOP:
	260	prtd->state &= ~ST_RUNNING;
	261	prtd->params->ops->stop(prtd->params->ch);
	262	break;
	263
	264	default:
	265	ret = -EINVAL;
	266	break;
	267	}
	268
	269	spin_unlock(&prtd->lock);
	270
	271	return ret;
	272	}
	273
	274	static snd_pcm_uframes_t
	275	dma_pointer(struct snd_pcm_substream *substream)
	276	{
	277	struct snd_pcm_runtime *runtime = substream->runtime;
	278	struct runtime_data *prtd = runtime->private_data;
	279	unsigned long res;
	280
	281	pr_debug("Entered %s\n", __func__);
	282
	283	res = prtd->dma_pos - prtd->dma_start;
	284
	285	pr_debug("Pointer offset: %lu\n", res);
	286
	287	/* we seem to be getting the odd error from the pcm library due
	288	* to out-of-bounds pointers. this is maybe due to the dma engine
	289	* not having loaded the new values for the channel before being
	290	* called... (todo - fix )
	291	*/
	292
	293	if (res >= snd_pcm_lib_buffer_bytes(substream)) {
	294	if (res == snd_pcm_lib_buffer_bytes(substream))
	295	res = 0;
	296	}
	297
	298	return bytes_to_frames(substream->runtime, res);
	299	}
	300
	301	static int dma_open(struct snd_pcm_substream *substream)
	302	{
	303	struct snd_pcm_runtime *runtime = substream->runtime;
	304	struct runtime_data *prtd;
	305
	306	pr_debug("Entered %s\n", __func__);
	307
	308	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	309	snd_soc_set_runtime_hwparams(substream, &dma_hardware);
	310
	311	prtd = kzalloc(sizeof(struct runtime_data), GFP_KERNEL);
	312	if (prtd == NULL)
	313	return -ENOMEM;
	314
	315	spin_lock_init(&prtd->lock);
	316
	317	runtime->private_data = prtd;
	318	return 0;
	319	}
	320
	321	static int dma_close(struct snd_pcm_substream *substream)
	322	{
	323	struct snd_pcm_runtime *runtime = substream->runtime;
	324	struct runtime_data *prtd = runtime->private_data;
	325
	326	pr_debug("Entered %s\n", __func__);
	327
	328	if (!prtd)
	329	pr_debug("dma_close called with prtd == NULL\n");
	330
	331	kfree(prtd);
	332
	333	return 0;
	334	}
	335
	336	static int dma_mmap(struct snd_pcm_substream *substream,
	337	struct vm_area_struct *vma)
	338	{
	339	struct snd_pcm_runtime *runtime = substream->runtime;
	340
	341	pr_debug("Entered %s\n", __func__);
	342
	343	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
	344	runtime->dma_area,
	345	runtime->dma_addr,
	346	runtime->dma_bytes);
	347	}
	348
	349	static struct snd_pcm_ops dma_ops = {
	350	.open = dma_open,
	351	.close = dma_close,
	352	.ioctl = snd_pcm_lib_ioctl,
	353	.hw_params = dma_hw_params,
	354	.hw_free = dma_hw_free,
	355	.prepare = dma_prepare,
	356	.trigger = dma_trigger,
	357	.pointer = dma_pointer,
	358	.mmap = dma_mmap,
	359	};
	360
	361	static int preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
	362	{
	363	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
	364	struct snd_dma_buffer *buf = &substream->dma_buffer;
	365	size_t size = dma_hardware.buffer_bytes_max;
	366
	367	pr_debug("Entered %s\n", __func__);
	368
	369	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	370	buf->dev.dev = pcm->card->dev;
	371	buf->private_data = NULL;
	372	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
	373	&buf->addr, GFP_KERNEL);
	374	if (!buf->area)
	375	return -ENOMEM;
	376	buf->bytes = size;
	377	return 0;
	378	}
	379
	380	static void dma_free_dma_buffers(struct snd_pcm *pcm)
	381	{
	382	struct snd_pcm_substream *substream;
	383	struct snd_dma_buffer *buf;
	384	int stream;
	385
	386	pr_debug("Entered %s\n", __func__);
	387
	388	for (stream = 0; stream < 2; stream++) {
	389	substream = pcm->streams[stream].substream;
	390	if (!substream)
	391	continue;
	392
	393	buf = &substream->dma_buffer;
	394	if (!buf->area)
	395	continue;
	396
	397	dma_free_writecombine(pcm->card->dev, buf->bytes,
	398	buf->area, buf->addr);
	399	buf->area = NULL;
	400	}
	401	}
	402
	403	static int dma_new(struct snd_soc_pcm_runtime *rtd)
	404	{
	405	struct snd_card *card = rtd->card->snd_card;
	406	struct snd_pcm *pcm = rtd->pcm;
	407	int ret;
	408
	409	pr_debug("Entered %s\n", __func__);
	410
	411	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
	412	if (ret)
	413	return ret;
	414
	415	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
	416	ret = preallocate_dma_buffer(pcm,
	417	SNDRV_PCM_STREAM_PLAYBACK);
	418	if (ret)
	419	goto out;
	420	}
	421
	422	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
	423	ret = preallocate_dma_buffer(pcm,
	424	SNDRV_PCM_STREAM_CAPTURE);
	425	if (ret)
	426	goto out;
	427	}
	428	out:
	429	return ret;
	430	}
	431
	432	static struct snd_soc_platform_driver samsung_asoc_platform = {
	433	.ops = &dma_ops,
	434	.pcm_new = dma_new,
	435	.pcm_free = dma_free_dma_buffers,
	436	};
	437
	438	void samsung_asoc_init_dma_data(struct snd_soc_dai *dai,
	439	struct s3c_dma_params *playback,
	440	struct s3c_dma_params *capture)
	441	{
	442	snd_soc_dai_init_dma_data(dai, playback, capture);
	443	}
	444	EXPORT_SYMBOL_GPL(samsung_asoc_init_dma_data);
	445
	446	int samsung_asoc_dma_platform_register(struct device *dev)
	447	{
	448	return devm_snd_soc_register_platform(dev, &samsung_asoc_platform);
	449	}
	450	EXPORT_SYMBOL_GPL(samsung_asoc_dma_platform_register);
	451
	452	MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
	453	MODULE_DESCRIPTION("Samsung ASoC DMA Driver");
	454	MODULE_LICENSE("GPL");