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

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  hdac-ext-controller.c - HD-audio extended controller functions.
  *
  *  Copyright (C) 2014-2015 Intel Corp
  *  Author: Jeeja KP <jeeja.kp@intel.com>
  *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */

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

 /*
  * processing pipe helpers - these helpers are useful for dealing with HDA
  * new capability of processing pipelines
  */

 /**
  * snd_hdac_ext_bus_ppcap_enable - enable/disable processing pipe capability
  * @bus: the pointer to HDAC bus object
  * @enable: flag to turn on/off the capability
  */
 void snd_hdac_ext_bus_ppcap_enable(struct hdac_bus *bus, bool enable)
 {

 	if (!bus->ppcap) {
 		dev_err(bus->dev, "Address of PP capability is NULL");
 		return;
 	}

 	if (enable)
 		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
 				 AZX_PPCTL_GPROCEN, AZX_PPCTL_GPROCEN);
 	else
 		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
 				 AZX_PPCTL_GPROCEN, 0);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_ppcap_enable);

 /**
  * snd_hdac_ext_bus_ppcap_int_enable - ppcap interrupt enable/disable
  * @bus: the pointer to HDAC bus object
  * @enable: flag to enable/disable interrupt
  */
 void snd_hdac_ext_bus_ppcap_int_enable(struct hdac_bus *bus, bool enable)
 {

 	if (!bus->ppcap) {
 		dev_err(bus->dev, "Address of PP capability is NULL\n");
 		return;
 	}

 	if (enable)
 		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
 				 AZX_PPCTL_PIE, AZX_PPCTL_PIE);
 	else
 		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
 				 AZX_PPCTL_PIE, 0);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_ppcap_int_enable);

 /*
  * Multilink helpers - these helpers are useful for dealing with HDA
  * new multilink capability
  */

 /**
  * snd_hdac_ext_bus_get_ml_capabilities - get multilink capability
  * @bus: the pointer to HDAC bus object
  *
  * This will parse all links and read the mlink capabilities and add them
  * in hlink_list of extended hdac bus
  * Note: this will be freed on bus exit by driver
  */
 int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_bus *bus)
 {
 	int idx;
 	u32 link_count;
 	struct hdac_ext_link *hlink;

 	link_count = readl(bus->mlcap + AZX_REG_ML_MLCD) + 1;

 	dev_dbg(bus->dev, "In %s Link count: %d\n", __func__, link_count);

 	for (idx = 0; idx < link_count; idx++) {
 		hlink  = kzalloc(sizeof(*hlink), GFP_KERNEL);
 		if (!hlink)
 			return -ENOMEM;
 		hlink->index = idx;
 		hlink->bus = bus;
 		hlink->ml_addr = bus->mlcap + AZX_ML_BASE +
 					(AZX_ML_INTERVAL * idx);
 		hlink->lcaps  = readl(hlink->ml_addr + AZX_REG_ML_LCAP);
 		hlink->lsdiid = readw(hlink->ml_addr + AZX_REG_ML_LSDIID);

 		/* since link in On, update the ref */
 		hlink->ref_count = 1;

 		list_add_tail(&hlink->list, &bus->hlink_list);
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_ml_capabilities);

 /**
  * snd_hdac_ext_link_free_all- free hdac extended link objects
  *
  * @bus: the pointer to HDAC bus object
  */

 void snd_hdac_ext_link_free_all(struct hdac_bus *bus)
 {
 	struct hdac_ext_link *hlink;

 	while (!list_empty(&bus->hlink_list)) {
 		hlink = list_first_entry(&bus->hlink_list, struct hdac_ext_link, list);
 		list_del(&hlink->list);
 		kfree(hlink);
 	}
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_link_free_all);

 /**
  * snd_hdac_ext_bus_get_hlink_by_addr - get hlink at specified address
  * @bus: hlink's parent bus device
  * @addr: codec device address
  *
  * Returns hlink object or NULL if matching hlink is not found.
  */
 struct hdac_ext_link *snd_hdac_ext_bus_get_hlink_by_addr(struct hdac_bus *bus, int addr)
 {
 	struct hdac_ext_link *hlink;

 	list_for_each_entry(hlink, &bus->hlink_list, list)
 		if (hlink->lsdiid & (0x1 << addr))
 			return hlink;
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_hlink_by_addr);

 /**
  * snd_hdac_ext_bus_get_hlink_by_name - get hlink based on codec name
  * @bus: the pointer to HDAC bus object
  * @codec_name: codec name
  */
 struct hdac_ext_link *snd_hdac_ext_bus_get_hlink_by_name(struct hdac_bus *bus,
 							 const char *codec_name)
 {
 	int bus_idx, addr;

 	if (sscanf(codec_name, "ehdaudio%dD%d", &bus_idx, &addr) != 2)
 		return NULL;
 	if (bus->idx != bus_idx)
 		return NULL;
 	if (addr < 0 || addr > 31)
 		return NULL;

 	return snd_hdac_ext_bus_get_hlink_by_addr(bus, addr);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_hlink_by_name);

 static int check_hdac_link_power_active(struct hdac_ext_link *hlink, bool enable)
 {
 	int timeout;
 	u32 val;
 	int mask = (1 << AZX_ML_LCTL_CPA_SHIFT);

 	udelay(3);
 	timeout = 150;

 	do {
 		val = readl(hlink->ml_addr + AZX_REG_ML_LCTL);
 		if (enable) {
 			if (((val & mask) >> AZX_ML_LCTL_CPA_SHIFT))
 				return 0;
 		} else {
 			if (!((val & mask) >> AZX_ML_LCTL_CPA_SHIFT))
 				return 0;
 		}
 		udelay(3);
 	} while (--timeout);

 	return -EIO;
 }

 /**
  * snd_hdac_ext_bus_link_power_up -power up hda link
  * @hlink: HD-audio extended link
  */
 int snd_hdac_ext_bus_link_power_up(struct hdac_ext_link *hlink)
 {
 	snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL,
 			 AZX_ML_LCTL_SPA, AZX_ML_LCTL_SPA);

 	return check_hdac_link_power_active(hlink, true);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_up);

 /**
  * snd_hdac_ext_bus_link_power_down -power down hda link
  * @hlink: HD-audio extended link
  */
 int snd_hdac_ext_bus_link_power_down(struct hdac_ext_link *hlink)
 {
 	snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL, AZX_ML_LCTL_SPA, 0);

 	return check_hdac_link_power_active(hlink, false);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down);

 /**
  * snd_hdac_ext_bus_link_power_up_all -power up all hda link
  * @bus: the pointer to HDAC bus object
  */
 int snd_hdac_ext_bus_link_power_up_all(struct hdac_bus *bus)
 {
 	struct hdac_ext_link *hlink = NULL;
 	int ret;

 	list_for_each_entry(hlink, &bus->hlink_list, list) {
 		ret = snd_hdac_ext_bus_link_power_up(hlink);
 		if (ret < 0)
 			return ret;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_up_all);

 /**
  * snd_hdac_ext_bus_link_power_down_all -power down all hda link
  * @bus: the pointer to HDAC bus object
  */
 int snd_hdac_ext_bus_link_power_down_all(struct hdac_bus *bus)
 {
 	struct hdac_ext_link *hlink = NULL;
 	int ret;

 	list_for_each_entry(hlink, &bus->hlink_list, list) {
 		ret = snd_hdac_ext_bus_link_power_down(hlink);
 		if (ret < 0)
 			return ret;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down_all);

 /**
  * snd_hdac_ext_bus_link_set_stream_id - maps stream id to link output
  * @link: HD-audio ext link to set up
  * @stream: stream id
  */
 void snd_hdac_ext_bus_link_set_stream_id(struct hdac_ext_link *link,
 					 int stream)
 {
 	snd_hdac_updatew(link->ml_addr, AZX_REG_ML_LOSIDV, (1 << stream), 1 << stream);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_set_stream_id);

 /**
  * snd_hdac_ext_bus_link_clear_stream_id - maps stream id to link output
  * @link: HD-audio ext link to set up
  * @stream: stream id
  */
 void snd_hdac_ext_bus_link_clear_stream_id(struct hdac_ext_link *link,
 					   int stream)
 {
 	snd_hdac_updatew(link->ml_addr, AZX_REG_ML_LOSIDV, (1 << stream), 0);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_clear_stream_id);

 int snd_hdac_ext_bus_link_get(struct hdac_bus *bus,
 				struct hdac_ext_link *hlink)
 {
 	unsigned long codec_mask;
 	int ret = 0;

 	mutex_lock(&bus->lock);

 	/*
 	 * if we move from 0 to 1, count will be 1 so power up this link
 	 * as well, also check the dma status and trigger that
 	 */
 	if (++hlink->ref_count == 1) {
 		if (!bus->cmd_dma_state) {
 			snd_hdac_bus_init_cmd_io(bus);
 			bus->cmd_dma_state = true;
 		}

 		ret = snd_hdac_ext_bus_link_power_up(hlink);

 		/*
 		 * clear the register to invalidate all the output streams
 		 */
 		snd_hdac_updatew(hlink->ml_addr, AZX_REG_ML_LOSIDV,
 				 AZX_ML_LOSIDV_STREAM_MASK, 0);
 		/*
 		 *  wait for 521usec for codec to report status
 		 *  HDA spec section 4.3 - Codec Discovery
 		 */
 		udelay(521);
 		codec_mask = snd_hdac_chip_readw(bus, STATESTS);
 		dev_dbg(bus->dev, "codec_mask = 0x%lx\n", codec_mask);
 		snd_hdac_chip_writew(bus, STATESTS, codec_mask);
 		if (!bus->codec_mask)
 			bus->codec_mask = codec_mask;
 	}

 	mutex_unlock(&bus->lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_get);

 int snd_hdac_ext_bus_link_put(struct hdac_bus *bus,
 			      struct hdac_ext_link *hlink)
 {
 	int ret = 0;
 	struct hdac_ext_link *hlink_tmp;
 	bool link_up = false;

 	mutex_lock(&bus->lock);

 	/*
 	 * if we move from 1 to 0, count will be 0
 	 * so power down this link as well
 	 */
 	if (--hlink->ref_count == 0) {
 		ret = snd_hdac_ext_bus_link_power_down(hlink);

 		/*
 		 * now check if all links are off, if so turn off
 		 * cmd dma as well
 		 */
 		list_for_each_entry(hlink_tmp, &bus->hlink_list, list) {
 			if (hlink_tmp->ref_count) {
 				link_up = true;
 				break;
 			}
 		}

 		if (!link_up) {
 			snd_hdac_bus_stop_cmd_io(bus);
 			bus->cmd_dma_state = false;
 		}
 	}

 	mutex_unlock(&bus->lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_put);

 static void hdac_ext_codec_link_up(struct hdac_device *codec)
 {
 	const char *devname = dev_name(&codec->dev);
 	struct hdac_ext_link *hlink =
 		snd_hdac_ext_bus_get_hlink_by_name(codec->bus, devname);

 	if (hlink)
 		snd_hdac_ext_bus_link_get(codec->bus, hlink);
 }

 static void hdac_ext_codec_link_down(struct hdac_device *codec)
 {
 	const char *devname = dev_name(&codec->dev);
 	struct hdac_ext_link *hlink =
 		snd_hdac_ext_bus_get_hlink_by_name(codec->bus, devname);

 	if (hlink)
 		snd_hdac_ext_bus_link_put(codec->bus, hlink);
 }

 void snd_hdac_ext_bus_link_power(struct hdac_device *codec, bool enable)
 {
 	struct hdac_bus *bus = codec->bus;
 	bool oldstate = test_bit(codec->addr, &bus->codec_powered);

 	if (enable == oldstate)
 		return;

 	snd_hdac_bus_link_power(codec, enable);

 	if (enable)
 		hdac_ext_codec_link_up(codec);
 	else
 		hdac_ext_codec_link_down(codec);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* hdac-ext-controller.c - HD-audio extended controller functions.
	*
	* Copyright (C) 2014-2015 Intel Corp
	* Author: Jeeja KP <jeeja.kp@intel.com>
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/

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

	/*
	* processing pipe helpers - these helpers are useful for dealing with HDA
	* new capability of processing pipelines
	*/

	/**
	* snd_hdac_ext_bus_ppcap_enable - enable/disable processing pipe capability
	* @bus: the pointer to HDAC bus object
	* @enable: flag to turn on/off the capability
	*/
	void snd_hdac_ext_bus_ppcap_enable(struct hdac_bus *bus, bool enable)
	{

	if (!bus->ppcap) {
	dev_err(bus->dev, "Address of PP capability is NULL");
	return;
	}

	if (enable)
	snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
	AZX_PPCTL_GPROCEN, AZX_PPCTL_GPROCEN);
	else
	snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
	AZX_PPCTL_GPROCEN, 0);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_ppcap_enable);

	/**
	* snd_hdac_ext_bus_ppcap_int_enable - ppcap interrupt enable/disable
	* @bus: the pointer to HDAC bus object
	* @enable: flag to enable/disable interrupt
	*/
	void snd_hdac_ext_bus_ppcap_int_enable(struct hdac_bus *bus, bool enable)
	{

	if (!bus->ppcap) {
	dev_err(bus->dev, "Address of PP capability is NULL\n");
	return;
	}

	if (enable)
	snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
	AZX_PPCTL_PIE, AZX_PPCTL_PIE);
	else
	snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
	AZX_PPCTL_PIE, 0);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_ppcap_int_enable);

	/*
	* Multilink helpers - these helpers are useful for dealing with HDA
	* new multilink capability
	*/

	/**
	* snd_hdac_ext_bus_get_ml_capabilities - get multilink capability
	* @bus: the pointer to HDAC bus object
	*
	* This will parse all links and read the mlink capabilities and add them
	* in hlink_list of extended hdac bus
	* Note: this will be freed on bus exit by driver
	*/
	int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_bus *bus)
	{
	int idx;
	u32 link_count;
	struct hdac_ext_link *hlink;

	link_count = readl(bus->mlcap + AZX_REG_ML_MLCD) + 1;

	dev_dbg(bus->dev, "In %s Link count: %d\n", __func__, link_count);

	for (idx = 0; idx < link_count; idx++) {
	hlink = kzalloc(sizeof(*hlink), GFP_KERNEL);
	if (!hlink)
	return -ENOMEM;
	hlink->index = idx;
	hlink->bus = bus;
	hlink->ml_addr = bus->mlcap + AZX_ML_BASE +
	(AZX_ML_INTERVAL * idx);
	hlink->lcaps = readl(hlink->ml_addr + AZX_REG_ML_LCAP);
	hlink->lsdiid = readw(hlink->ml_addr + AZX_REG_ML_LSDIID);

	/* since link in On, update the ref */
	hlink->ref_count = 1;

	list_add_tail(&hlink->list, &bus->hlink_list);
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_ml_capabilities);

	/**
	* snd_hdac_ext_link_free_all- free hdac extended link objects
	*
	* @bus: the pointer to HDAC bus object
	*/

	void snd_hdac_ext_link_free_all(struct hdac_bus *bus)
	{
	struct hdac_ext_link *hlink;

	while (!list_empty(&bus->hlink_list)) {
	hlink = list_first_entry(&bus->hlink_list, struct hdac_ext_link, list);
	list_del(&hlink->list);
	kfree(hlink);
	}
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_link_free_all);

	/**
	* snd_hdac_ext_bus_get_hlink_by_addr - get hlink at specified address
	* @bus: hlink's parent bus device
	* @addr: codec device address
	*
	* Returns hlink object or NULL if matching hlink is not found.
	*/
	struct hdac_ext_link snd_hdac_ext_bus_get_hlink_by_addr(struct hdac_bus bus, int addr)
	{
	struct hdac_ext_link *hlink;

	list_for_each_entry(hlink, &bus->hlink_list, list)
	if (hlink->lsdiid & (0x1 << addr))
	return hlink;
	return NULL;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_hlink_by_addr);

	/**
	* snd_hdac_ext_bus_get_hlink_by_name - get hlink based on codec name
	* @bus: the pointer to HDAC bus object
	* @codec_name: codec name
	*/
	struct hdac_ext_link snd_hdac_ext_bus_get_hlink_by_name(struct hdac_bus bus,
	const char *codec_name)
	{
	int bus_idx, addr;

	if (sscanf(codec_name, "ehdaudio%dD%d", &bus_idx, &addr) != 2)
	return NULL;
	if (bus->idx != bus_idx)
	return NULL;
	if (addr < 0 \|\| addr > 31)
	return NULL;

	return snd_hdac_ext_bus_get_hlink_by_addr(bus, addr);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_hlink_by_name);

	static int check_hdac_link_power_active(struct hdac_ext_link *hlink, bool enable)
	{
	int timeout;
	u32 val;
	int mask = (1 << AZX_ML_LCTL_CPA_SHIFT);

	udelay(3);
	timeout = 150;

	do {
	val = readl(hlink->ml_addr + AZX_REG_ML_LCTL);
	if (enable) {
	if (((val & mask) >> AZX_ML_LCTL_CPA_SHIFT))
	return 0;
	} else {
	if (!((val & mask) >> AZX_ML_LCTL_CPA_SHIFT))
	return 0;
	}
	udelay(3);
	} while (--timeout);

	return -EIO;
	}

	/**
	* snd_hdac_ext_bus_link_power_up -power up hda link
	* @hlink: HD-audio extended link
	*/
	int snd_hdac_ext_bus_link_power_up(struct hdac_ext_link *hlink)
	{
	snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL,
	AZX_ML_LCTL_SPA, AZX_ML_LCTL_SPA);

	return check_hdac_link_power_active(hlink, true);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_up);

	/**
	* snd_hdac_ext_bus_link_power_down -power down hda link
	* @hlink: HD-audio extended link
	*/
	int snd_hdac_ext_bus_link_power_down(struct hdac_ext_link *hlink)
	{
	snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL, AZX_ML_LCTL_SPA, 0);

	return check_hdac_link_power_active(hlink, false);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down);

	/**
	* snd_hdac_ext_bus_link_power_up_all -power up all hda link
	* @bus: the pointer to HDAC bus object
	*/
	int snd_hdac_ext_bus_link_power_up_all(struct hdac_bus *bus)
	{
	struct hdac_ext_link *hlink = NULL;
	int ret;

	list_for_each_entry(hlink, &bus->hlink_list, list) {
	ret = snd_hdac_ext_bus_link_power_up(hlink);
	if (ret < 0)
	return ret;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_up_all);

	/**
	* snd_hdac_ext_bus_link_power_down_all -power down all hda link
	* @bus: the pointer to HDAC bus object
	*/
	int snd_hdac_ext_bus_link_power_down_all(struct hdac_bus *bus)
	{
	struct hdac_ext_link *hlink = NULL;
	int ret;

	list_for_each_entry(hlink, &bus->hlink_list, list) {
	ret = snd_hdac_ext_bus_link_power_down(hlink);
	if (ret < 0)
	return ret;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down_all);

	/**
	* snd_hdac_ext_bus_link_set_stream_id - maps stream id to link output
	* @link: HD-audio ext link to set up
	* @stream: stream id
	*/
	void snd_hdac_ext_bus_link_set_stream_id(struct hdac_ext_link *link,
	int stream)
	{
	snd_hdac_updatew(link->ml_addr, AZX_REG_ML_LOSIDV, (1 << stream), 1 << stream);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_set_stream_id);

	/**
	* snd_hdac_ext_bus_link_clear_stream_id - maps stream id to link output
	* @link: HD-audio ext link to set up
	* @stream: stream id
	*/
	void snd_hdac_ext_bus_link_clear_stream_id(struct hdac_ext_link *link,
	int stream)
	{
	snd_hdac_updatew(link->ml_addr, AZX_REG_ML_LOSIDV, (1 << stream), 0);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_clear_stream_id);

	int snd_hdac_ext_bus_link_get(struct hdac_bus *bus,
	struct hdac_ext_link *hlink)
	{
	unsigned long codec_mask;
	int ret = 0;

	mutex_lock(&bus->lock);

	/*
	* if we move from 0 to 1, count will be 1 so power up this link
	* as well, also check the dma status and trigger that
	*/
	if (++hlink->ref_count == 1) {
	if (!bus->cmd_dma_state) {
	snd_hdac_bus_init_cmd_io(bus);
	bus->cmd_dma_state = true;
	}

	ret = snd_hdac_ext_bus_link_power_up(hlink);

	/*
	* clear the register to invalidate all the output streams
	*/
	snd_hdac_updatew(hlink->ml_addr, AZX_REG_ML_LOSIDV,
	AZX_ML_LOSIDV_STREAM_MASK, 0);
	/*
	* wait for 521usec for codec to report status
	* HDA spec section 4.3 - Codec Discovery
	*/
	udelay(521);
	codec_mask = snd_hdac_chip_readw(bus, STATESTS);
	dev_dbg(bus->dev, "codec_mask = 0x%lx\n", codec_mask);
	snd_hdac_chip_writew(bus, STATESTS, codec_mask);
	if (!bus->codec_mask)
	bus->codec_mask = codec_mask;
	}

	mutex_unlock(&bus->lock);
	return ret;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_get);

	int snd_hdac_ext_bus_link_put(struct hdac_bus *bus,
	struct hdac_ext_link *hlink)
	{
	int ret = 0;
	struct hdac_ext_link *hlink_tmp;
	bool link_up = false;

	mutex_lock(&bus->lock);

	/*
	* if we move from 1 to 0, count will be 0
	* so power down this link as well
	*/
	if (--hlink->ref_count == 0) {
	ret = snd_hdac_ext_bus_link_power_down(hlink);

	/*
	* now check if all links are off, if so turn off
	* cmd dma as well
	*/
	list_for_each_entry(hlink_tmp, &bus->hlink_list, list) {
	if (hlink_tmp->ref_count) {
	link_up = true;
	break;
	}
	}

	if (!link_up) {
	snd_hdac_bus_stop_cmd_io(bus);
	bus->cmd_dma_state = false;
	}
	}

	mutex_unlock(&bus->lock);
	return ret;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_put);

	static void hdac_ext_codec_link_up(struct hdac_device *codec)
	{
	const char *devname = dev_name(&codec->dev);
	struct hdac_ext_link *hlink =
	snd_hdac_ext_bus_get_hlink_by_name(codec->bus, devname);

	if (hlink)
	snd_hdac_ext_bus_link_get(codec->bus, hlink);
	}

	static void hdac_ext_codec_link_down(struct hdac_device *codec)
	{
	const char *devname = dev_name(&codec->dev);
	struct hdac_ext_link *hlink =
	snd_hdac_ext_bus_get_hlink_by_name(codec->bus, devname);

	if (hlink)
	snd_hdac_ext_bus_link_put(codec->bus, hlink);
	}

	void snd_hdac_ext_bus_link_power(struct hdac_device *codec, bool enable)
	{
	struct hdac_bus *bus = codec->bus;
	bool oldstate = test_bit(codec->addr, &bus->codec_powered);

	if (enable == oldstate)
	return;

	snd_hdac_bus_link_power(codec, enable);

	if (enable)
	hdac_ext_codec_link_up(codec);
	else
	hdac_ext_codec_link_down(codec);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power);