sound/hda/ext/hdac_ext_stream.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  hdac-ext-stream.c - HD-audio extended stream operations.
  *
  *  Copyright (C) 2015 Intel Corp
  *  Author: Jeeja KP <jeeja.kp@intel.com>
  *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */

 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <sound/pcm.h>
 #include <sound/hda_register.h>
 #include <sound/hdaudio_ext.h>
 #include <sound/compress_driver.h>

 /**
  * snd_hdac_ext_stream_init - initialize each stream (aka device)
  * @bus: HD-audio core bus
  * @hext_stream: HD-audio ext core stream object to initialize
  * @idx: stream index number
  * @direction: stream direction (SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE)
  * @tag: the tag id to assign
  *
  * initialize the stream, if ppcap is enabled then init those and then
  * invoke hdac stream initialization routine
  */
 static void snd_hdac_ext_stream_init(struct hdac_bus *bus,
 				     struct hdac_ext_stream *hext_stream,
 				     int idx, int direction, int tag)
 {
 	if (bus->ppcap) {
 		hext_stream->pphc_addr = bus->ppcap + AZX_PPHC_BASE +
 				AZX_PPHC_INTERVAL * idx;

 		hext_stream->pplc_addr = bus->ppcap + AZX_PPLC_BASE +
 				AZX_PPLC_MULTI * bus->num_streams +
 				AZX_PPLC_INTERVAL * idx;
 	}

 	hext_stream->decoupled = false;
 	snd_hdac_stream_init(bus, &hext_stream->hstream, idx, direction, tag);
 }

 /**
  * snd_hdac_ext_stream_init_all - create and initialize the stream objects
  *   for an extended hda bus
  * @bus: HD-audio core bus
  * @start_idx: start index for streams
  * @num_stream: number of streams to initialize
  * @dir: direction of streams
  */
 int snd_hdac_ext_stream_init_all(struct hdac_bus *bus, int start_idx,
 				 int num_stream, int dir)
 {
 	int stream_tag = 0;
 	int i, tag, idx = start_idx;

 	for (i = 0; i < num_stream; i++) {
 		struct hdac_ext_stream *hext_stream =
 				kzalloc(sizeof(*hext_stream), GFP_KERNEL);
 		if (!hext_stream)
 			return -ENOMEM;
 		tag = ++stream_tag;
 		snd_hdac_ext_stream_init(bus, hext_stream, idx, dir, tag);
 		idx++;
 	}

 	return 0;

 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_init_all);

 /**
  * snd_hdac_ext_stream_free_all - free hdac extended stream objects
  *
  * @bus: HD-audio core bus
  */
 void snd_hdac_ext_stream_free_all(struct hdac_bus *bus)
 {
 	struct hdac_stream *s, *_s;
 	struct hdac_ext_stream *hext_stream;

 	list_for_each_entry_safe(s, _s, &bus->stream_list, list) {
 		hext_stream = stream_to_hdac_ext_stream(s);
 		snd_hdac_ext_stream_decouple(bus, hext_stream, false);
 		list_del(&s->list);
 		kfree(hext_stream);
 	}
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_free_all);

 void snd_hdac_ext_stream_decouple_locked(struct hdac_bus *bus,
 					 struct hdac_ext_stream *hext_stream,
 					 bool decouple)
 {
 	struct hdac_stream *hstream = &hext_stream->hstream;
 	u32 val;
 	int mask = AZX_PPCTL_PROCEN(hstream->index);

 	val = readw(bus->ppcap + AZX_REG_PP_PPCTL) & mask;

 	if (decouple && !val)
 		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL, mask, mask);
 	else if (!decouple && val)
 		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL, mask, 0);

 	hext_stream->decoupled = decouple;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_decouple_locked);

 /**
  * snd_hdac_ext_stream_decouple - decouple the hdac stream
  * @bus: HD-audio core bus
  * @hext_stream: HD-audio ext core stream object to initialize
  * @decouple: flag to decouple
  */
 void snd_hdac_ext_stream_decouple(struct hdac_bus *bus,
 				  struct hdac_ext_stream *hext_stream, bool decouple)
 {
 	spin_lock_irq(&bus->reg_lock);
 	snd_hdac_ext_stream_decouple_locked(bus, hext_stream, decouple);
 	spin_unlock_irq(&bus->reg_lock);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_decouple);

 /**
  * snd_hdac_ext_stream_start - start a stream
  * @hext_stream: HD-audio ext core stream to start
  */
 void snd_hdac_ext_stream_start(struct hdac_ext_stream *hext_stream)
 {
 	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL,
 			 AZX_PPLCCTL_RUN, AZX_PPLCCTL_RUN);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_start);

 /**
  * snd_hdac_ext_stream_clear - stop a stream DMA
  * @hext_stream: HD-audio ext core stream to stop
  */
 void snd_hdac_ext_stream_clear(struct hdac_ext_stream *hext_stream)
 {
 	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL, AZX_PPLCCTL_RUN, 0);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_clear);

 /**
  * snd_hdac_ext_stream_reset - reset a stream
  * @hext_stream: HD-audio ext core stream to reset
  */
 void snd_hdac_ext_stream_reset(struct hdac_ext_stream *hext_stream)
 {
 	unsigned char val;
 	int timeout;

 	snd_hdac_ext_stream_clear(hext_stream);

 	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL,
 			 AZX_PPLCCTL_STRST, AZX_PPLCCTL_STRST);
 	udelay(3);
 	timeout = 50;
 	do {
 		val = readl(hext_stream->pplc_addr + AZX_REG_PPLCCTL) &
 				AZX_PPLCCTL_STRST;
 		if (val)
 			break;
 		udelay(3);
 	} while (--timeout);
 	val &= ~AZX_PPLCCTL_STRST;
 	writel(val, hext_stream->pplc_addr + AZX_REG_PPLCCTL);
 	udelay(3);

 	timeout = 50;
 	/* waiting for hardware to report that the stream is out of reset */
 	do {
 		val = readl(hext_stream->pplc_addr + AZX_REG_PPLCCTL) & AZX_PPLCCTL_STRST;
 		if (!val)
 			break;
 		udelay(3);
 	} while (--timeout);

 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_reset);

 /**
  * snd_hdac_ext_stream_setup -  set up the SD for streaming
  * @hext_stream: HD-audio ext core stream to set up
  * @fmt: stream format
  */
 int snd_hdac_ext_stream_setup(struct hdac_ext_stream *hext_stream, int fmt)
 {
 	struct hdac_stream *hstream = &hext_stream->hstream;
 	unsigned int val;

 	/* make sure the run bit is zero for SD */
 	snd_hdac_ext_stream_clear(hext_stream);
 	/* program the stream_tag */
 	val = readl(hext_stream->pplc_addr + AZX_REG_PPLCCTL);
 	val = (val & ~AZX_PPLCCTL_STRM_MASK) |
 		(hstream->stream_tag << AZX_PPLCCTL_STRM_SHIFT);
 	writel(val, hext_stream->pplc_addr + AZX_REG_PPLCCTL);

 	/* program the stream format */
 	writew(fmt, hext_stream->pplc_addr + AZX_REG_PPLCFMT);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_setup);

 static struct hdac_ext_stream *
 hdac_ext_link_dma_stream_assign(struct hdac_bus *bus,
 				struct snd_pcm_substream *substream)
 {
 	struct hdac_ext_stream *res = NULL;
 	struct hdac_stream *hstream = NULL;

 	if (!bus->ppcap) {
 		dev_err(bus->dev, "stream type not supported\n");
 		return NULL;
 	}

 	spin_lock_irq(&bus->reg_lock);
 	list_for_each_entry(hstream, &bus->stream_list, list) {
 		struct hdac_ext_stream *hext_stream = container_of(hstream,
 								 struct hdac_ext_stream,
 								 hstream);
 		if (hstream->direction != substream->stream)
 			continue;

 		/* check if link stream is available */
 		if (!hext_stream->link_locked) {
 			res = hext_stream;
 			break;
 		}

 	}
 	if (res) {
 		snd_hdac_ext_stream_decouple_locked(bus, res, true);
 		res->link_locked = 1;
 		res->link_substream = substream;
 	}
 	spin_unlock_irq(&bus->reg_lock);
 	return res;
 }

 static struct hdac_ext_stream *
 hdac_ext_host_dma_stream_assign(struct hdac_bus *bus,
 				struct snd_pcm_substream *substream)
 {
 	struct hdac_ext_stream *res = NULL;
 	struct hdac_stream *hstream = NULL;

 	if (!bus->ppcap) {
 		dev_err(bus->dev, "stream type not supported\n");
 		return NULL;
 	}

 	spin_lock_irq(&bus->reg_lock);
 	list_for_each_entry(hstream, &bus->stream_list, list) {
 		struct hdac_ext_stream *hext_stream = container_of(hstream,
 								 struct hdac_ext_stream,
 								 hstream);
 		if (hstream->direction != substream->stream)
 			continue;

 		if (!hstream->opened) {
 			res = hext_stream;
 			break;
 		}
 	}
 	if (res) {
 		snd_hdac_ext_stream_decouple_locked(bus, res, true);
 		res->hstream.opened = 1;
 		res->hstream.running = 0;
 		res->hstream.substream = substream;
 	}
 	spin_unlock_irq(&bus->reg_lock);

 	return res;
 }

 /**
  * snd_hdac_ext_stream_assign - assign a stream for the PCM
  * @bus: HD-audio core bus
  * @substream: PCM substream to assign
  * @type: type of stream (coupled, host or link stream)
  *
  * This assigns the stream based on the type (coupled/host/link), for the
  * given PCM substream, assigns it and returns the stream object
  *
  * coupled: Looks for an unused stream
  * host: Looks for an unused decoupled host stream
  * link: Looks for an unused decoupled link stream
  *
  * If no stream is free, returns NULL. The function tries to keep using
  * the same stream object when it's used beforehand.  when a stream is
  * decoupled, it becomes a host stream and link stream.
  */
 struct hdac_ext_stream *snd_hdac_ext_stream_assign(struct hdac_bus *bus,
 					   struct snd_pcm_substream *substream,
 					   int type)
 {
 	struct hdac_ext_stream *hext_stream = NULL;
 	struct hdac_stream *hstream = NULL;

 	switch (type) {
 	case HDAC_EXT_STREAM_TYPE_COUPLED:
 		hstream = snd_hdac_stream_assign(bus, substream);
 		if (hstream)
 			hext_stream = container_of(hstream,
 						   struct hdac_ext_stream,
 						   hstream);
 		return hext_stream;

 	case HDAC_EXT_STREAM_TYPE_HOST:
 		return hdac_ext_host_dma_stream_assign(bus, substream);

 	case HDAC_EXT_STREAM_TYPE_LINK:
 		return hdac_ext_link_dma_stream_assign(bus, substream);

 	default:
 		return NULL;
 	}
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_assign);

 /**
  * snd_hdac_ext_stream_release - release the assigned stream
  * @hext_stream: HD-audio ext core stream to release
  * @type: type of stream (coupled, host or link stream)
  *
  * Release the stream that has been assigned by snd_hdac_ext_stream_assign().
  */
 void snd_hdac_ext_stream_release(struct hdac_ext_stream *hext_stream, int type)
 {
 	struct hdac_bus *bus = hext_stream->hstream.bus;

 	switch (type) {
 	case HDAC_EXT_STREAM_TYPE_COUPLED:
 		snd_hdac_stream_release(&hext_stream->hstream);
 		break;

 	case HDAC_EXT_STREAM_TYPE_HOST:
 		spin_lock_irq(&bus->reg_lock);
 		/* couple link only if not in use */
 		if (!hext_stream->link_locked)
 			snd_hdac_ext_stream_decouple_locked(bus, hext_stream, false);
 		snd_hdac_stream_release_locked(&hext_stream->hstream);
 		spin_unlock_irq(&bus->reg_lock);
 		break;

 	case HDAC_EXT_STREAM_TYPE_LINK:
 		spin_lock_irq(&bus->reg_lock);
 		/* couple host only if not in use */
 		if (!hext_stream->hstream.opened)
 			snd_hdac_ext_stream_decouple_locked(bus, hext_stream, false);
 		hext_stream->link_locked = 0;
 		hext_stream->link_substream = NULL;
 		spin_unlock_irq(&bus->reg_lock);
 		break;

 	default:
 		dev_dbg(bus->dev, "Invalid type %d\n", type);
 	}

 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_release);

 /**
  * snd_hdac_ext_cstream_assign - assign a host stream for compress
  * @bus: HD-audio core bus
  * @cstream: Compress stream to assign
  *
  * Assign an unused host stream for the given compress stream.
  * If no stream is free, NULL is returned. Stream is decoupled
  * before assignment.
  */
 struct hdac_ext_stream *snd_hdac_ext_cstream_assign(struct hdac_bus *bus,
 						    struct snd_compr_stream *cstream)
 {
 	struct hdac_ext_stream *res = NULL;
 	struct hdac_stream *hstream;

 	spin_lock_irq(&bus->reg_lock);
 	list_for_each_entry(hstream, &bus->stream_list, list) {
 		struct hdac_ext_stream *hext_stream = stream_to_hdac_ext_stream(hstream);

 		if (hstream->direction != cstream->direction)
 			continue;

 		if (!hstream->opened) {
 			res = hext_stream;
 			break;
 		}
 	}

 	if (res) {
 		snd_hdac_ext_stream_decouple_locked(bus, res, true);
 		res->hstream.opened = 1;
 		res->hstream.running = 0;
 		res->hstream.cstream = cstream;
 	}
 	spin_unlock_irq(&bus->reg_lock);

 	return res;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_cstream_assign);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* hdac-ext-stream.c - HD-audio extended stream operations.
	*
	* Copyright (C) 2015 Intel Corp
	* Author: Jeeja KP <jeeja.kp@intel.com>
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/

	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <sound/pcm.h>
	#include <sound/hda_register.h>
	#include <sound/hdaudio_ext.h>
	#include <sound/compress_driver.h>

	/**
	* snd_hdac_ext_stream_init - initialize each stream (aka device)
	* @bus: HD-audio core bus
	* @hext_stream: HD-audio ext core stream object to initialize
	* @idx: stream index number
	* @direction: stream direction (SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE)
	* @tag: the tag id to assign
	*
	* initialize the stream, if ppcap is enabled then init those and then
	* invoke hdac stream initialization routine
	*/
	static void snd_hdac_ext_stream_init(struct hdac_bus *bus,
	struct hdac_ext_stream *hext_stream,
	int idx, int direction, int tag)
	{
	if (bus->ppcap) {
	hext_stream->pphc_addr = bus->ppcap + AZX_PPHC_BASE +
	AZX_PPHC_INTERVAL * idx;

	hext_stream->pplc_addr = bus->ppcap + AZX_PPLC_BASE +
	AZX_PPLC_MULTI * bus->num_streams +
	AZX_PPLC_INTERVAL * idx;
	}

	hext_stream->decoupled = false;
	snd_hdac_stream_init(bus, &hext_stream->hstream, idx, direction, tag);
	}

	/**
	* snd_hdac_ext_stream_init_all - create and initialize the stream objects
	* for an extended hda bus
	* @bus: HD-audio core bus
	* @start_idx: start index for streams
	* @num_stream: number of streams to initialize
	* @dir: direction of streams
	*/
	int snd_hdac_ext_stream_init_all(struct hdac_bus *bus, int start_idx,
	int num_stream, int dir)
	{
	int stream_tag = 0;
	int i, tag, idx = start_idx;

	for (i = 0; i < num_stream; i++) {
	struct hdac_ext_stream *hext_stream =
	kzalloc(sizeof(*hext_stream), GFP_KERNEL);
	if (!hext_stream)
	return -ENOMEM;
	tag = ++stream_tag;
	snd_hdac_ext_stream_init(bus, hext_stream, idx, dir, tag);
	idx++;
	}

	return 0;

	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_init_all);

	/**
	* snd_hdac_ext_stream_free_all - free hdac extended stream objects
	*
	* @bus: HD-audio core bus
	*/
	void snd_hdac_ext_stream_free_all(struct hdac_bus *bus)
	{
	struct hdac_stream s, _s;
	struct hdac_ext_stream *hext_stream;

	list_for_each_entry_safe(s, _s, &bus->stream_list, list) {
	hext_stream = stream_to_hdac_ext_stream(s);
	snd_hdac_ext_stream_decouple(bus, hext_stream, false);
	list_del(&s->list);
	kfree(hext_stream);
	}
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_free_all);

	void snd_hdac_ext_stream_decouple_locked(struct hdac_bus *bus,
	struct hdac_ext_stream *hext_stream,
	bool decouple)
	{
	struct hdac_stream *hstream = &hext_stream->hstream;
	u32 val;
	int mask = AZX_PPCTL_PROCEN(hstream->index);

	val = readw(bus->ppcap + AZX_REG_PP_PPCTL) & mask;

	if (decouple && !val)
	snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL, mask, mask);
	else if (!decouple && val)
	snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL, mask, 0);

	hext_stream->decoupled = decouple;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_decouple_locked);

	/**
	* snd_hdac_ext_stream_decouple - decouple the hdac stream
	* @bus: HD-audio core bus
	* @hext_stream: HD-audio ext core stream object to initialize
	* @decouple: flag to decouple
	*/
	void snd_hdac_ext_stream_decouple(struct hdac_bus *bus,
	struct hdac_ext_stream *hext_stream, bool decouple)
	{
	spin_lock_irq(&bus->reg_lock);
	snd_hdac_ext_stream_decouple_locked(bus, hext_stream, decouple);
	spin_unlock_irq(&bus->reg_lock);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_decouple);

	/**
	* snd_hdac_ext_stream_start - start a stream
	* @hext_stream: HD-audio ext core stream to start
	*/
	void snd_hdac_ext_stream_start(struct hdac_ext_stream *hext_stream)
	{
	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL,
	AZX_PPLCCTL_RUN, AZX_PPLCCTL_RUN);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_start);

	/**
	* snd_hdac_ext_stream_clear - stop a stream DMA
	* @hext_stream: HD-audio ext core stream to stop
	*/
	void snd_hdac_ext_stream_clear(struct hdac_ext_stream *hext_stream)
	{
	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL, AZX_PPLCCTL_RUN, 0);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_clear);

	/**
	* snd_hdac_ext_stream_reset - reset a stream
	* @hext_stream: HD-audio ext core stream to reset
	*/
	void snd_hdac_ext_stream_reset(struct hdac_ext_stream *hext_stream)
	{
	unsigned char val;
	int timeout;

	snd_hdac_ext_stream_clear(hext_stream);

	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL,
	AZX_PPLCCTL_STRST, AZX_PPLCCTL_STRST);
	udelay(3);
	timeout = 50;
	do {
	val = readl(hext_stream->pplc_addr + AZX_REG_PPLCCTL) &
	AZX_PPLCCTL_STRST;
	if (val)
	break;
	udelay(3);
	} while (--timeout);
	val &= ~AZX_PPLCCTL_STRST;
	writel(val, hext_stream->pplc_addr + AZX_REG_PPLCCTL);
	udelay(3);

	timeout = 50;
	/* waiting for hardware to report that the stream is out of reset */
	do {
	val = readl(hext_stream->pplc_addr + AZX_REG_PPLCCTL) & AZX_PPLCCTL_STRST;
	if (!val)
	break;
	udelay(3);
	} while (--timeout);

	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_reset);

	/**
	* snd_hdac_ext_stream_setup - set up the SD for streaming
	* @hext_stream: HD-audio ext core stream to set up
	* @fmt: stream format
	*/
	int snd_hdac_ext_stream_setup(struct hdac_ext_stream *hext_stream, int fmt)
	{
	struct hdac_stream *hstream = &hext_stream->hstream;
	unsigned int val;

	/* make sure the run bit is zero for SD */
	snd_hdac_ext_stream_clear(hext_stream);
	/* program the stream_tag */
	val = readl(hext_stream->pplc_addr + AZX_REG_PPLCCTL);
	val = (val & ~AZX_PPLCCTL_STRM_MASK) \|
	(hstream->stream_tag << AZX_PPLCCTL_STRM_SHIFT);
	writel(val, hext_stream->pplc_addr + AZX_REG_PPLCCTL);

	/* program the stream format */
	writew(fmt, hext_stream->pplc_addr + AZX_REG_PPLCFMT);

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_setup);

	static struct hdac_ext_stream *
	hdac_ext_link_dma_stream_assign(struct hdac_bus *bus,
	struct snd_pcm_substream *substream)
	{
	struct hdac_ext_stream *res = NULL;
	struct hdac_stream *hstream = NULL;

	if (!bus->ppcap) {
	dev_err(bus->dev, "stream type not supported\n");
	return NULL;
	}

	spin_lock_irq(&bus->reg_lock);
	list_for_each_entry(hstream, &bus->stream_list, list) {
	struct hdac_ext_stream *hext_stream = container_of(hstream,
	struct hdac_ext_stream,
	hstream);
	if (hstream->direction != substream->stream)
	continue;

	/* check if link stream is available */
	if (!hext_stream->link_locked) {
	res = hext_stream;
	break;
	}

	}
	if (res) {
	snd_hdac_ext_stream_decouple_locked(bus, res, true);
	res->link_locked = 1;
	res->link_substream = substream;
	}
	spin_unlock_irq(&bus->reg_lock);
	return res;
	}

	static struct hdac_ext_stream *
	hdac_ext_host_dma_stream_assign(struct hdac_bus *bus,
	struct snd_pcm_substream *substream)
	{
	struct hdac_ext_stream *res = NULL;
	struct hdac_stream *hstream = NULL;

	if (!bus->ppcap) {
	dev_err(bus->dev, "stream type not supported\n");
	return NULL;
	}

	spin_lock_irq(&bus->reg_lock);
	list_for_each_entry(hstream, &bus->stream_list, list) {
	struct hdac_ext_stream *hext_stream = container_of(hstream,
	struct hdac_ext_stream,
	hstream);
	if (hstream->direction != substream->stream)
	continue;

	if (!hstream->opened) {
	res = hext_stream;
	break;
	}
	}
	if (res) {
	snd_hdac_ext_stream_decouple_locked(bus, res, true);
	res->hstream.opened = 1;
	res->hstream.running = 0;
	res->hstream.substream = substream;
	}
	spin_unlock_irq(&bus->reg_lock);

	return res;
	}

	/**
	* snd_hdac_ext_stream_assign - assign a stream for the PCM
	* @bus: HD-audio core bus
	* @substream: PCM substream to assign
	* @type: type of stream (coupled, host or link stream)
	*
	* This assigns the stream based on the type (coupled/host/link), for the
	* given PCM substream, assigns it and returns the stream object
	*
	* coupled: Looks for an unused stream
	* host: Looks for an unused decoupled host stream
	* link: Looks for an unused decoupled link stream
	*
	* If no stream is free, returns NULL. The function tries to keep using
	* the same stream object when it's used beforehand. when a stream is
	* decoupled, it becomes a host stream and link stream.
	*/
	struct hdac_ext_stream snd_hdac_ext_stream_assign(struct hdac_bus bus,
	struct snd_pcm_substream *substream,
	int type)
	{
	struct hdac_ext_stream *hext_stream = NULL;
	struct hdac_stream *hstream = NULL;

	switch (type) {
	case HDAC_EXT_STREAM_TYPE_COUPLED:
	hstream = snd_hdac_stream_assign(bus, substream);
	if (hstream)
	hext_stream = container_of(hstream,
	struct hdac_ext_stream,
	hstream);
	return hext_stream;

	case HDAC_EXT_STREAM_TYPE_HOST:
	return hdac_ext_host_dma_stream_assign(bus, substream);

	case HDAC_EXT_STREAM_TYPE_LINK:
	return hdac_ext_link_dma_stream_assign(bus, substream);

	default:
	return NULL;
	}
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_assign);

	/**
	* snd_hdac_ext_stream_release - release the assigned stream
	* @hext_stream: HD-audio ext core stream to release
	* @type: type of stream (coupled, host or link stream)
	*
	* Release the stream that has been assigned by snd_hdac_ext_stream_assign().
	*/
	void snd_hdac_ext_stream_release(struct hdac_ext_stream *hext_stream, int type)
	{
	struct hdac_bus *bus = hext_stream->hstream.bus;

	switch (type) {
	case HDAC_EXT_STREAM_TYPE_COUPLED:
	snd_hdac_stream_release(&hext_stream->hstream);
	break;

	case HDAC_EXT_STREAM_TYPE_HOST:
	spin_lock_irq(&bus->reg_lock);
	/* couple link only if not in use */
	if (!hext_stream->link_locked)
	snd_hdac_ext_stream_decouple_locked(bus, hext_stream, false);
	snd_hdac_stream_release_locked(&hext_stream->hstream);
	spin_unlock_irq(&bus->reg_lock);
	break;

	case HDAC_EXT_STREAM_TYPE_LINK:
	spin_lock_irq(&bus->reg_lock);
	/* couple host only if not in use */
	if (!hext_stream->hstream.opened)
	snd_hdac_ext_stream_decouple_locked(bus, hext_stream, false);
	hext_stream->link_locked = 0;
	hext_stream->link_substream = NULL;
	spin_unlock_irq(&bus->reg_lock);
	break;

	default:
	dev_dbg(bus->dev, "Invalid type %d\n", type);
	}

	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_release);

	/**
	* snd_hdac_ext_cstream_assign - assign a host stream for compress
	* @bus: HD-audio core bus
	* @cstream: Compress stream to assign
	*
	* Assign an unused host stream for the given compress stream.
	* If no stream is free, NULL is returned. Stream is decoupled
	* before assignment.
	*/
	struct hdac_ext_stream snd_hdac_ext_cstream_assign(struct hdac_bus bus,
	struct snd_compr_stream *cstream)
	{
	struct hdac_ext_stream *res = NULL;
	struct hdac_stream *hstream;

	spin_lock_irq(&bus->reg_lock);
	list_for_each_entry(hstream, &bus->stream_list, list) {
	struct hdac_ext_stream *hext_stream = stream_to_hdac_ext_stream(hstream);

	if (hstream->direction != cstream->direction)
	continue;

	if (!hstream->opened) {
	res = hext_stream;
	break;
	}
	}

	if (res) {
	snd_hdac_ext_stream_decouple_locked(bus, res, true);
	res->hstream.opened = 1;
	res->hstream.running = 0;
	res->hstream.cstream = cstream;
	}
	spin_unlock_irq(&bus->reg_lock);

	return res;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_cstream_assign);