[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,
	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
				    SNDRV_PCM_FMTBIT_U16_LE |
				    SNDRV_PCM_FMTBIT_U8 |
				    SNDRV_PCM_FMTBIT_S8,
	.channels_min		= 2,
	.channels_max		= 2,
	.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;

	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 u64 dma_mask = DMA_BIT_MASK(32);

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 = 0;

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

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

	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,
};

int asoc_dma_platform_register(struct device *dev)
{
	return snd_soc_register_platform(dev, &samsung_asoc_platform);
}
EXPORT_SYMBOL_GPL(asoc_dma_platform_register);

void asoc_dma_platform_unregister(struct device *dev)
{
	snd_soc_unregister_platform(dev);
}
EXPORT_SYMBOL_GPL(asoc_dma_platform_unregister);

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	.formats = SNDRV_PCM_FMTBIT_S16_LE \|
	39	SNDRV_PCM_FMTBIT_U16_LE \|
	40	SNDRV_PCM_FMTBIT_U8 \|
	41	SNDRV_PCM_FMTBIT_S8,
	42	.channels_min = 2,
	43	.channels_max = 2,
	44	.buffer_bytes_max = 128*1024,
	45	.period_bytes_min = PAGE_SIZE,
	46	.period_bytes_max = PAGE_SIZE*2,
	47	.periods_min = 2,
	48	.periods_max = 128,
	49	.fifo_size = 32,
	50	};
	51
	52	struct runtime_data {
	53	spinlock_t lock;
	54	int state;
	55	unsigned int dma_loaded;
	56	unsigned int dma_period;
	57	dma_addr_t dma_start;
	58	dma_addr_t dma_pos;
	59	dma_addr_t dma_end;
	60	struct s3c_dma_params *params;
	61	};
	62
	63	static void audio_buffdone(void *data);
	64
	65	/* dma_enqueue
	66	*
	67	* place a dma buffer onto the queue for the dma system
	68	* to handle.
	69	*/
	70	static void dma_enqueue(struct snd_pcm_substream *substream)
	71	{
	72	struct runtime_data *prtd = substream->runtime->private_data;
	73	dma_addr_t pos = prtd->dma_pos;
	74	unsigned int limit;
	75	struct samsung_dma_prep dma_info;
	76
	77	pr_debug("Entered %s\n", __func__);
	78
	79	limit = (prtd->dma_end - prtd->dma_start) / prtd->dma_period;
	80
	81	pr_debug("%s: loaded %d, limit %d\n",
	82	__func__, prtd->dma_loaded, limit);
	83
	84	dma_info.cap = (samsung_dma_has_circular() ? DMA_CYCLIC : DMA_SLAVE);
	85	dma_info.direction =
	86	(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
	87	? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
	88	dma_info.fp = audio_buffdone;
	89	dma_info.fp_param = substream;
	90	dma_info.period = prtd->dma_period;
	91	dma_info.len = prtd->dma_period*limit;
	92
	93	while (prtd->dma_loaded < limit) {
	94	pr_debug("dma_loaded: %d\n", prtd->dma_loaded);
	95
	96	if ((pos + dma_info.period) > prtd->dma_end) {
	97	dma_info.period = prtd->dma_end - pos;
	98	pr_debug("%s: corrected dma len %ld\n",
	99	__func__, dma_info.period);
	100	}
	101
	102	dma_info.buf = pos;
	103	prtd->params->ops->prepare(prtd->params->ch, &dma_info);
	104
	105	prtd->dma_loaded++;
	106	pos += prtd->dma_period;
	107	if (pos >= prtd->dma_end)
	108	pos = prtd->dma_start;
	109	}
	110
	111	prtd->dma_pos = pos;
	112	}
	113
	114	static void audio_buffdone(void *data)
	115	{
	116	struct snd_pcm_substream *substream = data;
	117	struct runtime_data *prtd = substream->runtime->private_data;
	118
	119	pr_debug("Entered %s\n", __func__);
	120
	121	if (prtd->state & ST_RUNNING) {
	122	prtd->dma_pos += prtd->dma_period;
	123	if (prtd->dma_pos >= prtd->dma_end)
	124	prtd->dma_pos = prtd->dma_start;
	125
	126	if (substream)
	127	snd_pcm_period_elapsed(substream);
	128
	129	spin_lock(&prtd->lock);
	130	if (!samsung_dma_has_circular()) {
	131	prtd->dma_loaded--;
	132	dma_enqueue(substream);
	133	}
	134	spin_unlock(&prtd->lock);
	135	}
	136	}
	137
	138	static int dma_hw_params(struct snd_pcm_substream *substream,
	139	struct snd_pcm_hw_params *params)
	140	{
	141	struct snd_pcm_runtime *runtime = substream->runtime;
	142	struct runtime_data *prtd = runtime->private_data;
	143	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	144	unsigned long totbytes = params_buffer_bytes(params);
	145	struct s3c_dma_params *dma =
	146	snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
	147	struct samsung_dma_req req;
	148	struct samsung_dma_config config;
	149
	150	pr_debug("Entered %s\n", __func__);
	151
	152	/* return if this is a bufferless transfer e.g.
	153	* codec <--> BT codec or GSM modem -- lg FIXME */
	154	if (!dma)
	155	return 0;
	156
	157	/* this may get called several times by oss emulation
	158	* with different params -HW */
	159	if (prtd->params == NULL) {
	160	/* prepare DMA */
	161	prtd->params = dma;
	162
	163	pr_debug("params %p, client %p, channel %d\n", prtd->params,
	164	prtd->params->client, prtd->params->channel);
	165
	166	prtd->params->ops = samsung_dma_get_ops();
	167
	168	req.cap = (samsung_dma_has_circular() ?
	169	DMA_CYCLIC : DMA_SLAVE);
	170	req.client = prtd->params->client;
	171	config.direction =
	172	(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
	173	? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
	174	config.width = prtd->params->dma_size;
	175	config.fifo = prtd->params->dma_addr;
	176	prtd->params->ch = prtd->params->ops->request(
	177	prtd->params->channel, &req, rtd->cpu_dai->dev,
	178	prtd->params->ch_name);
	179	if (!prtd->params->ch) {
	180	pr_err("Failed to allocate DMA channel\n");
	181	return -ENXIO;
	182	}
	183	prtd->params->ops->config(prtd->params->ch, &config);
	184	}
	185
	186	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
	187
	188	runtime->dma_bytes = totbytes;
	189
	190	spin_lock_irq(&prtd->lock);
	191	prtd->dma_loaded = 0;
	192	prtd->dma_period = params_period_bytes(params);
	193	prtd->dma_start = runtime->dma_addr;
	194	prtd->dma_pos = prtd->dma_start;
	195	prtd->dma_end = prtd->dma_start + totbytes;
	196	spin_unlock_irq(&prtd->lock);
	197
	198	return 0;
	199	}
	200
	201	static int dma_hw_free(struct snd_pcm_substream *substream)
	202	{
	203	struct runtime_data *prtd = substream->runtime->private_data;
	204
	205	pr_debug("Entered %s\n", __func__);
	206
	207	snd_pcm_set_runtime_buffer(substream, NULL);
	208
	209	if (prtd->params) {
	210	prtd->params->ops->flush(prtd->params->ch);
	211	prtd->params->ops->release(prtd->params->ch,
	212	prtd->params->client);
	213	prtd->params = NULL;
	214	}
	215
	216	return 0;
	217	}
	218
	219	static int dma_prepare(struct snd_pcm_substream *substream)
	220	{
	221	struct runtime_data *prtd = substream->runtime->private_data;
	222	int ret = 0;
	223
	224	pr_debug("Entered %s\n", __func__);
	225
	226	/* return if this is a bufferless transfer e.g.
	227	* codec <--> BT codec or GSM modem -- lg FIXME */
	228	if (!prtd->params)
	229	return 0;
	230
	231	/* flush the DMA channel */
	232	prtd->params->ops->flush(prtd->params->ch);
	233
	234	prtd->dma_loaded = 0;
	235	prtd->dma_pos = prtd->dma_start;
	236
	237	/* enqueue dma buffers */
	238	dma_enqueue(substream);
	239
	240	return ret;
	241	}
	242
	243	static int dma_trigger(struct snd_pcm_substream *substream, int cmd)
	244	{
	245	struct runtime_data *prtd = substream->runtime->private_data;
	246	int ret = 0;
	247
	248	pr_debug("Entered %s\n", __func__);
	249
	250	spin_lock(&prtd->lock);
	251
	252	switch (cmd) {
	253	case SNDRV_PCM_TRIGGER_START:
	254	prtd->state \|= ST_RUNNING;
	255	prtd->params->ops->trigger(prtd->params->ch);
	256	break;
	257
	258	case SNDRV_PCM_TRIGGER_STOP:
	259	prtd->state &= ~ST_RUNNING;
	260	prtd->params->ops->stop(prtd->params->ch);
	261	break;
	262
	263	default:
	264	ret = -EINVAL;
	265	break;
	266	}
	267
	268	spin_unlock(&prtd->lock);
	269
	270	return ret;
	271	}
	272
	273	static snd_pcm_uframes_t
	274	dma_pointer(struct snd_pcm_substream *substream)
	275	{
	276	struct snd_pcm_runtime *runtime = substream->runtime;
	277	struct runtime_data *prtd = runtime->private_data;
	278	unsigned long res;
	279
	280	pr_debug("Entered %s\n", __func__);
	281
	282	res = prtd->dma_pos - prtd->dma_start;
	283
	284	pr_debug("Pointer offset: %lu\n", res);
	285
	286	/* we seem to be getting the odd error from the pcm library due
	287	* to out-of-bounds pointers. this is maybe due to the dma engine
	288	* not having loaded the new values for the channel before being
	289	* called... (todo - fix )
	290	*/
	291
	292	if (res >= snd_pcm_lib_buffer_bytes(substream)) {
	293	if (res == snd_pcm_lib_buffer_bytes(substream))
	294	res = 0;
	295	}
	296
	297	return bytes_to_frames(substream->runtime, res);
	298	}
	299
	300	static int dma_open(struct snd_pcm_substream *substream)
	301	{
	302	struct snd_pcm_runtime *runtime = substream->runtime;
	303	struct runtime_data *prtd;
	304
	305	pr_debug("Entered %s\n", __func__);
	306
	307	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	308	snd_soc_set_runtime_hwparams(substream, &dma_hardware);
	309
	310	prtd = kzalloc(sizeof(struct runtime_data), GFP_KERNEL);
	311	if (prtd == NULL)
	312	return -ENOMEM;
	313
	314	spin_lock_init(&prtd->lock);
	315
	316	runtime->private_data = prtd;
	317	return 0;
	318	}
	319
	320	static int dma_close(struct snd_pcm_substream *substream)
	321	{
	322	struct snd_pcm_runtime *runtime = substream->runtime;
	323	struct runtime_data *prtd = runtime->private_data;
	324
	325	pr_debug("Entered %s\n", __func__);
	326
	327	if (!prtd)
	328	pr_debug("dma_close called with prtd == NULL\n");
	329
	330	kfree(prtd);
	331
	332	return 0;
	333	}
	334
	335	static int dma_mmap(struct snd_pcm_substream *substream,
	336	struct vm_area_struct *vma)
	337	{
	338	struct snd_pcm_runtime *runtime = substream->runtime;
	339
	340	pr_debug("Entered %s\n", __func__);
	341
	342	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
	343	runtime->dma_area,
	344	runtime->dma_addr,
	345	runtime->dma_bytes);
	346	}
	347
	348	static struct snd_pcm_ops dma_ops = {
	349	.open = dma_open,
	350	.close = dma_close,
	351	.ioctl = snd_pcm_lib_ioctl,
	352	.hw_params = dma_hw_params,
	353	.hw_free = dma_hw_free,
	354	.prepare = dma_prepare,
	355	.trigger = dma_trigger,
	356	.pointer = dma_pointer,
	357	.mmap = dma_mmap,
	358	};
	359
	360	static int preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
	361	{
	362	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
	363	struct snd_dma_buffer *buf = &substream->dma_buffer;
	364	size_t size = dma_hardware.buffer_bytes_max;
	365
	366	pr_debug("Entered %s\n", __func__);
	367
	368	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	369	buf->dev.dev = pcm->card->dev;
	370	buf->private_data = NULL;
	371	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
	372	&buf->addr, GFP_KERNEL);
	373	if (!buf->area)
	374	return -ENOMEM;
	375	buf->bytes = size;
	376	return 0;
	377	}
	378
	379	static void dma_free_dma_buffers(struct snd_pcm *pcm)
	380	{
	381	struct snd_pcm_substream *substream;
	382	struct snd_dma_buffer *buf;
	383	int stream;
	384
	385	pr_debug("Entered %s\n", __func__);
	386
	387	for (stream = 0; stream < 2; stream++) {
	388	substream = pcm->streams[stream].substream;
	389	if (!substream)
	390	continue;
	391
	392	buf = &substream->dma_buffer;
	393	if (!buf->area)
	394	continue;
	395
	396	dma_free_writecombine(pcm->card->dev, buf->bytes,
	397	buf->area, buf->addr);
	398	buf->area = NULL;
	399	}
	400	}
	401
	402	static u64 dma_mask = DMA_BIT_MASK(32);
	403
	404	static int dma_new(struct snd_soc_pcm_runtime *rtd)
	405	{
	406	struct snd_card *card = rtd->card->snd_card;
	407	struct snd_pcm *pcm = rtd->pcm;
	408	int ret = 0;
	409
	410	pr_debug("Entered %s\n", __func__);
	411
	412	if (!card->dev->dma_mask)
	413	card->dev->dma_mask = &dma_mask;
	414	if (!card->dev->coherent_dma_mask)
	415	card->dev->coherent_dma_mask = DMA_BIT_MASK(32);
	416
	417	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
	418	ret = preallocate_dma_buffer(pcm,
	419	SNDRV_PCM_STREAM_PLAYBACK);
	420	if (ret)
	421	goto out;
	422	}
	423
	424	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
	425	ret = preallocate_dma_buffer(pcm,
	426	SNDRV_PCM_STREAM_CAPTURE);
	427	if (ret)
	428	goto out;
	429	}
	430	out:
	431	return ret;
	432	}
	433
	434	static struct snd_soc_platform_driver samsung_asoc_platform = {
	435	.ops = &dma_ops,
	436	.pcm_new = dma_new,
	437	.pcm_free = dma_free_dma_buffers,
	438	};
	439
	440	int asoc_dma_platform_register(struct device *dev)
	441	{
	442	return snd_soc_register_platform(dev, &samsung_asoc_platform);
	443	}
	444	EXPORT_SYMBOL_GPL(asoc_dma_platform_register);
	445
	446	void asoc_dma_platform_unregister(struct device *dev)
	447	{
	448	snd_soc_unregister_platform(dev);
	449	}
	450	EXPORT_SYMBOL_GPL(asoc_dma_platform_unregister);
	451
	452	MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
	453	MODULE_DESCRIPTION("Samsung ASoC DMA Driver");
	454	MODULE_LICENSE("GPL");