[GitHub/mt8127/android_kernel_alcatel_ttab.git] / sound / soc / soc-dmaengine-pcm.c

/*
 *  Copyright (C) 2012, Analog Devices Inc.
 *	Author: Lars-Peter Clausen <lars@metafoo.de>
 *
 *  Based on:
 *	imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
 *	mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
 *	ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
 *		      Copyright (C) 2006 Applied Data Systems
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/dmaengine.h>
#include <linux/slab.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <sound/dmaengine_pcm.h>

struct dmaengine_pcm_runtime_data {
	struct dma_chan *dma_chan;
	dma_cookie_t cookie;

	unsigned int pos;
};

static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
	const struct snd_pcm_substream *substream)
{
	return substream->runtime->private_data;
}

struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

	return prtd->dma_chan;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);

/**
 * snd_hwparams_to_dma_slave_config - Convert hw_params to dma_slave_config
 * @substream: PCM substream
 * @params: hw_params
 * @slave_config: DMA slave config
 *
 * This function can be used to initialize a dma_slave_config from a substream
 * and hw_params in a dmaengine based PCM driver implementation.
 */
int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
	const struct snd_pcm_hw_params *params,
	struct dma_slave_config *slave_config)
{
	enum dma_slave_buswidth buswidth;

	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S8:
		buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
		break;
	case SNDRV_PCM_FORMAT_S16_LE:
		buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
		break;
	case SNDRV_PCM_FORMAT_S18_3LE:
	case SNDRV_PCM_FORMAT_S20_3LE:
	case SNDRV_PCM_FORMAT_S24_LE:
	case SNDRV_PCM_FORMAT_S32_LE:
		buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
		break;
	default:
		return -EINVAL;
	}

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		slave_config->direction = DMA_MEM_TO_DEV;
		slave_config->dst_addr_width = buswidth;
	} else {
		slave_config->direction = DMA_DEV_TO_MEM;
		slave_config->src_addr_width = buswidth;
	}

	slave_config->device_fc = false;

	return 0;
}
EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);

/**
 * snd_dmaengine_pcm_set_config_from_dai_data() - Initializes a dma slave config
 *  using DAI DMA data.
 * @substream: PCM substream
 * @dma_data: DAI DMA data
 * @slave_config: DMA slave configuration
 *
 * Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width and
 * slave_id fields of the DMA slave config from the same fields of the DAI DMA
 * data struct. The src and dst fields will be initialized depending on the
 * direction of the substream. If the substream is a playback stream the dst
 * fields will be initialized, if it is a capture stream the src fields will be
 * initialized. The {dst,src}_addr_width field will only be initialized if the
 * addr_width field of the DAI DMA data struct is not equal to
 * DMA_SLAVE_BUSWIDTH_UNDEFINED.
 */
void snd_dmaengine_pcm_set_config_from_dai_data(
	const struct snd_pcm_substream *substream,
	const struct snd_dmaengine_dai_dma_data *dma_data,
	struct dma_slave_config *slave_config)
{
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		slave_config->dst_addr = dma_data->addr;
		slave_config->dst_maxburst = dma_data->maxburst;
		if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
			slave_config->dst_addr_width = dma_data->addr_width;
	} else {
		slave_config->src_addr = dma_data->addr;
		slave_config->src_maxburst = dma_data->maxburst;
		if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
			slave_config->src_addr_width = dma_data->addr_width;
	}

	slave_config->slave_id = dma_data->slave_id;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);

static void dmaengine_pcm_dma_complete(void *arg)
{
	struct snd_pcm_substream *substream = arg;
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

	prtd->pos += snd_pcm_lib_period_bytes(substream);
	if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
		prtd->pos = 0;

	snd_pcm_period_elapsed(substream);
}

static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	struct dma_chan *chan = prtd->dma_chan;
	struct dma_async_tx_descriptor *desc;
	enum dma_transfer_direction direction;
	unsigned long flags = DMA_CTRL_ACK;

	direction = snd_pcm_substream_to_dma_direction(substream);

	if (!substream->runtime->no_period_wakeup)
		flags |= DMA_PREP_INTERRUPT;

	prtd->pos = 0;
	desc = dmaengine_prep_dma_cyclic(chan,
		substream->runtime->dma_addr,
		snd_pcm_lib_buffer_bytes(substream),
		snd_pcm_lib_period_bytes(substream), direction, flags);

	if (!desc)
		return -ENOMEM;

	desc->callback = dmaengine_pcm_dma_complete;
	desc->callback_param = substream;
	prtd->cookie = dmaengine_submit(desc);

	return 0;
}

/**
 * snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
 * @substream: PCM substream
 * @cmd: Trigger command
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * This function can be used as the PCM trigger callback for dmaengine based PCM
 * driver implementations.
 */
int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	int ret;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		ret = dmaengine_pcm_prepare_and_submit(substream);
		if (ret)
			return ret;
		dma_async_issue_pending(prtd->dma_chan);
		break;
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		dmaengine_resume(prtd->dma_chan);
		break;
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		dmaengine_pause(prtd->dma_chan);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
		dmaengine_terminate_all(prtd->dma_chan);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);

/**
 * snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
 * @substream: PCM substream
 *
 * This function is deprecated and should not be used by new drivers, as its
 * results may be unreliable.
 */
snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	return bytes_to_frames(substream->runtime, prtd->pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);

/**
 * snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
 * @substream: PCM substream
 *
 * This function can be used as the PCM pointer callback for dmaengine based PCM
 * driver implementations.
 */
snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	struct dma_tx_state state;
	enum dma_status status;
	unsigned int buf_size;
	unsigned int pos = 0;

	status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
	if (status == DMA_IN_PROGRESS || status == DMA_PAUSED) {
		buf_size = snd_pcm_lib_buffer_bytes(substream);
		if (state.residue > 0 && state.residue <= buf_size)
			pos = buf_size - state.residue;
	}

	return bytes_to_frames(substream->runtime, pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);

/**
 * snd_dmaengine_pcm_request_channel - Request channel for the dmaengine PCM
 * @filter_fn: Filter function used to request the DMA channel
 * @filter_data: Data passed to the DMA filter function
 *
 * Returns NULL or the requested DMA channel.
 *
 * This function request a DMA channel for usage with dmaengine PCM.
 */
struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
	void *filter_data)
{
	dma_cap_mask_t mask;

	dma_cap_zero(mask);
	dma_cap_set(DMA_SLAVE, mask);
	dma_cap_set(DMA_CYCLIC, mask);

	return dma_request_channel(mask, filter_fn, filter_data);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_request_channel);

/**
 * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
 * @substream: PCM substream
 * @chan: DMA channel to use for data transfers
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * The function should usually be called from the pcm open callback. Note that
 * this function will use private_data field of the substream's runtime. So it
 * is not availabe to your pcm driver implementation.
 */
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
	struct dma_chan *chan)
{
	struct dmaengine_pcm_runtime_data *prtd;
	int ret;

	if (!chan)
		return -ENXIO;

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

	prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
	if (!prtd)
		return -ENOMEM;

	prtd->dma_chan = chan;

	substream->runtime->private_data = prtd;

	return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);

/**
 * snd_dmaengine_pcm_open_request_chan - Open a dmaengine based PCM substream and request channel
 * @substream: PCM substream
 * @filter_fn: Filter function used to request the DMA channel
 * @filter_data: Data passed to the DMA filter function
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * This function will request a DMA channel using the passed filter function and
 * data. The function should usually be called from the pcm open callback. Note
 * that this function will use private_data field of the substream's runtime. So
 * it is not availabe to your pcm driver implementation.
 */
int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
	dma_filter_fn filter_fn, void *filter_data)
{
	return snd_dmaengine_pcm_open(substream,
		    snd_dmaengine_pcm_request_channel(filter_fn, filter_data));
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);

/**
 * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
 * @substream: PCM substream
 */
int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

	kfree(prtd);

	return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);

/**
 * snd_dmaengine_pcm_release_chan_close - Close a dmaengine based PCM substream and release channel
 * @substream: PCM substream
 *
 * Releases the DMA channel associated with the PCM substream.
 */
int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
{
	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

	dma_release_channel(prtd->dma_chan);

	return snd_dmaengine_pcm_close(substream);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);

MODULE_LICENSE("GPL");
Commit	Line	Data
e7f73a16 LPC	1	/*
	2	* Copyright (C) 2012, Analog Devices Inc.
	3	* Author: Lars-Peter Clausen <lars@metafoo.de>
	4	*
	5	* Based on:
	6	* imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
	7	* mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
	8	* ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
	9	* Copyright (C) 2006 Applied Data Systems
	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	* You should have received a copy of the GNU General Public License along
	17	* with this program; if not, write to the Free Software Foundation, Inc.,
	18	* 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*
	20	*/
	21	#include <linux/module.h>
	22	#include <linux/init.h>
	23	#include <linux/dmaengine.h>
	24	#include <linux/slab.h>
	25	#include <sound/pcm.h>
	26	#include <sound/pcm_params.h>
	27	#include <sound/soc.h>
	28
	29	#include <sound/dmaengine_pcm.h>
	30
	31	struct dmaengine_pcm_runtime_data {
	32	struct dma_chan *dma_chan;
3528f27a	33	dma_cookie_t cookie;
e7f73a16 LPC	34
e7f73a16 LPC	35	unsigned int pos;
e7f73a16 LPC	36	};
	37
	38	static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
	39	const struct snd_pcm_substream *substream)
	40	{
	41	return substream->runtime->private_data;
	42	}
	43
e7f73a16 LPC	44	struct dma_chan snd_dmaengine_pcm_get_chan(struct snd_pcm_substream substream)
	45	{
	46	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	47
	48	return prtd->dma_chan;
	49	}
	50	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);
	51
	52	/**
	53	* snd_hwparams_to_dma_slave_config - Convert hw_params to dma_slave_config
	54	* @substream: PCM substream
	55	* @params: hw_params
	56	* @slave_config: DMA slave config
	57	*
	58	* This function can be used to initialize a dma_slave_config from a substream
	59	* and hw_params in a dmaengine based PCM driver implementation.
	60	*/
	61	int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
	62	const struct snd_pcm_hw_params *params,
	63	struct dma_slave_config *slave_config)
	64	{
	65	enum dma_slave_buswidth buswidth;
	66
	67	switch (params_format(params)) {
	68	case SNDRV_PCM_FORMAT_S8:
	69	buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
	70	break;
	71	case SNDRV_PCM_FORMAT_S16_LE:
	72	buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
	73	break;
	74	case SNDRV_PCM_FORMAT_S18_3LE:
	75	case SNDRV_PCM_FORMAT_S20_3LE:
	76	case SNDRV_PCM_FORMAT_S24_LE:
	77	case SNDRV_PCM_FORMAT_S32_LE:
	78	buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
	79	break;
	80	default:
	81	return -EINVAL;
	82	}
	83
	84	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	85	slave_config->direction = DMA_MEM_TO_DEV;
	86	slave_config->dst_addr_width = buswidth;
	87	} else {
	88	slave_config->direction = DMA_DEV_TO_MEM;
	89	slave_config->src_addr_width = buswidth;
	90	}
	91
5fa70f71 LPC	92	slave_config->device_fc = false;
5fa70f71 LPC	93
e7f73a16 LPC	94	return 0;
	95	}
	96	EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
	97
85c9f9c5 LPC	98	/**
	99	* snd_dmaengine_pcm_set_config_from_dai_data() - Initializes a dma slave config
	100	* using DAI DMA data.
	101	* @substream: PCM substream
	102	* @dma_data: DAI DMA data
	103	* @slave_config: DMA slave configuration
	104	*
	105	* Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width and
	106	* slave_id fields of the DMA slave config from the same fields of the DAI DMA
	107	* data struct. The src and dst fields will be initialized depending on the
	108	* direction of the substream. If the substream is a playback stream the dst
	109	* fields will be initialized, if it is a capture stream the src fields will be
	110	* initialized. The {dst,src}_addr_width field will only be initialized if the
	111	* addr_width field of the DAI DMA data struct is not equal to
	112	* DMA_SLAVE_BUSWIDTH_UNDEFINED.
	113	*/
	114	void snd_dmaengine_pcm_set_config_from_dai_data(
	115	const struct snd_pcm_substream *substream,
	116	const struct snd_dmaengine_dai_dma_data *dma_data,
	117	struct dma_slave_config *slave_config)
	118	{
	119	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	120	slave_config->dst_addr = dma_data->addr;
	121	slave_config->dst_maxburst = dma_data->maxburst;
	122	if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
	123	slave_config->dst_addr_width = dma_data->addr_width;
	124	} else {
	125	slave_config->src_addr = dma_data->addr;
	126	slave_config->src_maxburst = dma_data->maxburst;
	127	if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
	128	slave_config->src_addr_width = dma_data->addr_width;
	129	}
	130
	131	slave_config->slave_id = dma_data->slave_id;
	132	}
	133	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);
	134
e7f73a16 LPC	135	static void dmaengine_pcm_dma_complete(void *arg)
	136	{
	137	struct snd_pcm_substream *substream = arg;
	138	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	139
	140	prtd->pos += snd_pcm_lib_period_bytes(substream);
	141	if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
	142	prtd->pos = 0;
	143
	144	snd_pcm_period_elapsed(substream);
	145	}
	146
	147	static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
	148	{
	149	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	150	struct dma_chan *chan = prtd->dma_chan;
	151	struct dma_async_tx_descriptor *desc;
	152	enum dma_transfer_direction direction;
e7736cde	153	unsigned long flags = DMA_CTRL_ACK;
e7f73a16 LPC	154
	155	direction = snd_pcm_substream_to_dma_direction(substream);
	156
e7736cde PU	157	if (!substream->runtime->no_period_wakeup)
	158	flags \|= DMA_PREP_INTERRUPT;
	159
7a08cf70	160	prtd->pos = 0;
41ba6b71	161	desc = dmaengine_prep_dma_cyclic(chan,
e7f73a16 LPC	162	substream->runtime->dma_addr,
e7f73a16 LPC	163	snd_pcm_lib_buffer_bytes(substream),
e7736cde	164	snd_pcm_lib_period_bytes(substream), direction, flags);
e7f73a16 LPC	165
	166	if (!desc)
	167	return -ENOMEM;
	168
	169	desc->callback = dmaengine_pcm_dma_complete;
	170	desc->callback_param = substream;
3528f27a	171	prtd->cookie = dmaengine_submit(desc);
e7f73a16 LPC	172
	173	return 0;
	174	}
	175
	176	/**
	177	* snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
	178	* @substream: PCM substream
	179	* @cmd: Trigger command
	180	*
	181	* Returns 0 on success, a negative error code otherwise.
	182	*
	183	* This function can be used as the PCM trigger callback for dmaengine based PCM
	184	* driver implementations.
	185	*/
	186	int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
	187	{
	188	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	189	int ret;
	190
	191	switch (cmd) {
	192	case SNDRV_PCM_TRIGGER_START:
	193	ret = dmaengine_pcm_prepare_and_submit(substream);
	194	if (ret)
	195	return ret;
	196	dma_async_issue_pending(prtd->dma_chan);
	197	break;
	198	case SNDRV_PCM_TRIGGER_RESUME:
	199	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
	200	dmaengine_resume(prtd->dma_chan);
	201	break;
	202	case SNDRV_PCM_TRIGGER_SUSPEND:
	203	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
	204	dmaengine_pause(prtd->dma_chan);
	205	break;
	206	case SNDRV_PCM_TRIGGER_STOP:
	207	dmaengine_terminate_all(prtd->dma_chan);
	208	break;
	209	default:
	210	return -EINVAL;
	211	}
	212
	213	return 0;
	214	}
	215	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);
	216
	217	/**
9883ab22	218	* snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
e7f73a16 LPC	219	* @substream: PCM substream
e7f73a16 LPC	220	*
9883ab22 LPC	221	* This function is deprecated and should not be used by new drivers, as its
9883ab22 LPC	222	* results may be unreliable.
e7f73a16	223	*/
9883ab22	224	snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
e7f73a16 LPC	225	{
	226	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	227	return bytes_to_frames(substream->runtime, prtd->pos);
	228	}
9883ab22	229	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);
e7f73a16	230
3528f27a LPC	231	/**
	232	* snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
	233	* @substream: PCM substream
	234	*
	235	* This function can be used as the PCM pointer callback for dmaengine based PCM
	236	* driver implementations.
	237	*/
	238	snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
	239	{
	240	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	241	struct dma_tx_state state;
	242	enum dma_status status;
	243	unsigned int buf_size;
	244	unsigned int pos = 0;
	245
	246	status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
	247	if (status == DMA_IN_PROGRESS \|\| status == DMA_PAUSED) {
	248	buf_size = snd_pcm_lib_buffer_bytes(substream);
	249	if (state.residue > 0 && state.residue <= buf_size)
	250	pos = buf_size - state.residue;
	251	}
	252
	253	return bytes_to_frames(substream->runtime, pos);
	254	}
	255	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
	256
c999836d LPC	257	/**
	258	* snd_dmaengine_pcm_request_channel - Request channel for the dmaengine PCM
	259	* @filter_fn: Filter function used to request the DMA channel
	260	* @filter_data: Data passed to the DMA filter function
	261	*
	262	* Returns NULL or the requested DMA channel.
	263	*
	264	* This function request a DMA channel for usage with dmaengine PCM.
	265	*/
	266	struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
7c1c1d4a	267	void *filter_data)
e7f73a16 LPC	268	{
	269	dma_cap_mask_t mask;
	270
	271	dma_cap_zero(mask);
	272	dma_cap_set(DMA_SLAVE, mask);
	273	dma_cap_set(DMA_CYCLIC, mask);
e7f73a16	274
7c1c1d4a	275	return dma_request_channel(mask, filter_fn, filter_data);
e7f73a16	276	}
c999836d	277	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_request_channel);
e7f73a16 LPC	278
	279	/**
	280	* snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
	281	* @substream: PCM substream
7c1c1d4a	282	* @chan: DMA channel to use for data transfers
e7f73a16 LPC	283	*
	284	* Returns 0 on success, a negative error code otherwise.
	285	*
7c1c1d4a LPC	286	* The function should usually be called from the pcm open callback. Note that
	287	* this function will use private_data field of the substream's runtime. So it
	288	* is not availabe to your pcm driver implementation.
e7f73a16 LPC	289	*/
e7f73a16 LPC	290	int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
7c1c1d4a	291	struct dma_chan *chan)
e7f73a16 LPC	292	{
	293	struct dmaengine_pcm_runtime_data *prtd;
	294	int ret;
	295
7c1c1d4a LPC	296	if (!chan)
	297	return -ENXIO;
	298
e7f73a16 LPC	299	ret = snd_pcm_hw_constraint_integer(substream->runtime,
	300	SNDRV_PCM_HW_PARAM_PERIODS);
	301	if (ret < 0)
	302	return ret;
	303
	304	prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
	305	if (!prtd)
	306	return -ENOMEM;
	307
7c1c1d4a	308	prtd->dma_chan = chan;
e7f73a16 LPC	309
	310	substream->runtime->private_data = prtd;
	311
	312	return 0;
	313	}
	314	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
	315
7c1c1d4a LPC	316	/**
	317	* snd_dmaengine_pcm_open_request_chan - Open a dmaengine based PCM substream and request channel
	318	* @substream: PCM substream
	319	* @filter_fn: Filter function used to request the DMA channel
	320	* @filter_data: Data passed to the DMA filter function
	321	*
	322	* Returns 0 on success, a negative error code otherwise.
	323	*
	324	* This function will request a DMA channel using the passed filter function and
	325	* data. The function should usually be called from the pcm open callback. Note
	326	* that this function will use private_data field of the substream's runtime. So
	327	* it is not availabe to your pcm driver implementation.
	328	*/
	329	int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
	330	dma_filter_fn filter_fn, void *filter_data)
	331	{
	332	return snd_dmaengine_pcm_open(substream,
c999836d	333	snd_dmaengine_pcm_request_channel(filter_fn, filter_data));
7c1c1d4a LPC	334	}
	335	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);
	336
e7f73a16 LPC	337	/**
	338	* snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
	339	* @substream: PCM substream
	340	*/
	341	int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
	342	{
	343	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	344
e7f73a16 LPC	345	kfree(prtd);
	346
	347	return 0;
	348	}
	349	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);
cba69b4d	350
7c1c1d4a LPC	351	/**
	352	* snd_dmaengine_pcm_release_chan_close - Close a dmaengine based PCM substream and release channel
	353	* @substream: PCM substream
	354	*
	355	* Releases the DMA channel associated with the PCM substream.
	356	*/
	357	int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
	358	{
	359	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
	360
	361	dma_release_channel(prtd->dma_chan);
	362
	363	return snd_dmaengine_pcm_close(substream);
	364	}
	365	EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);
	366
cba69b4d	367	MODULE_LICENSE("GPL");