drivers/gpu/drm/i915/intel_lpe_audio.c - linux - Git at Google

 /*
  * Copyright © 2016 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  * IN THE SOFTWARE.
  *
  * Authors:
  *    Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
  *    Jerome Anand <jerome.anand@intel.com>
  *    based on VED patches
  *
  */

 /**
  * DOC: LPE Audio integration for HDMI or DP playback
  *
  * Motivation:
  * Atom platforms (e.g. valleyview and cherryTrail) integrates a DMA-based
  * interface as an alternative to the traditional HDaudio path. While this
  * mode is unrelated to the LPE aka SST audio engine, the documentation refers
  * to this mode as LPE so we keep this notation for the sake of consistency.
  *
  * The interface is handled by a separate standalone driver maintained in the
  * ALSA subsystem for simplicity. To minimize the interaction between the two
  * subsystems, a bridge is setup between the hdmi-lpe-audio and i915:
  * 1. Create a platform device to share MMIO/IRQ resources
  * 2. Make the platform device child of i915 device for runtime PM.
  * 3. Create IRQ chip to forward the LPE audio irqs.
  * the hdmi-lpe-audio driver probes the lpe audio device and creates a new
  * sound card
  *
  * Threats:
  * Due to the restriction in Linux platform device model, user need manually
  * uninstall the hdmi-lpe-audio driver before uninstalling i915 module,
  * otherwise we might run into use-after-free issues after i915 removes the
  * platform device: even though hdmi-lpe-audio driver is released, the modules
  * is still in "installed" status.
  *
  * Implementation:
  * The MMIO/REG platform resources are created according to the registers
  * specification.
  * When forwarding LPE audio irqs, the flow control handler selection depends
  * on the platform, for example on valleyview handle_simple_irq is enough.
  *
  */

 #include <linux/acpi.h>
 #include <linux/device.h>
 #include <linux/pci.h>
 #include <linux/pm_runtime.h>

 #include "i915_drv.h"
 #include <linux/delay.h>
 #include <drm/intel_lpe_audio.h>

 #define HAS_LPE_AUDIO(dev_priv) ((dev_priv)->lpe_audio.platdev != NULL)

 static struct platform_device *
 lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
 {
 	int ret;
 	struct drm_device *dev = &dev_priv->drm;
 	struct platform_device_info pinfo = {};
 	struct resource *rsc;
 	struct platform_device *platdev;
 	struct intel_hdmi_lpe_audio_pdata *pdata;

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

 	rsc = kcalloc(2, sizeof(*rsc), GFP_KERNEL);
 	if (!rsc) {
 		kfree(pdata);
 		return ERR_PTR(-ENOMEM);
 	}

 	rsc[0].start    = rsc[0].end = dev_priv->lpe_audio.irq;
 	rsc[0].flags    = IORESOURCE_IRQ;
 	rsc[0].name     = "hdmi-lpe-audio-irq";

 	rsc[1].start    = pci_resource_start(dev->pdev, 0) +
 		I915_HDMI_LPE_AUDIO_BASE;
 	rsc[1].end      = pci_resource_start(dev->pdev, 0) +
 		I915_HDMI_LPE_AUDIO_BASE + I915_HDMI_LPE_AUDIO_SIZE - 1;
 	rsc[1].flags    = IORESOURCE_MEM;
 	rsc[1].name     = "hdmi-lpe-audio-mmio";

 	pinfo.parent = dev->dev;
 	pinfo.name = "hdmi-lpe-audio";
 	pinfo.id = -1;
 	pinfo.res = rsc;
 	pinfo.num_res = 2;
 	pinfo.data = pdata;
 	pinfo.size_data = sizeof(*pdata);
 	pinfo.dma_mask = DMA_BIT_MASK(32);

 	pdata->num_pipes = INTEL_INFO(dev_priv)->num_pipes;
 	pdata->num_ports = IS_CHERRYVIEW(dev_priv) ? 3 : 2; /* B,C,D or B,C */
 	pdata->port[0].pipe = -1;
 	pdata->port[1].pipe = -1;
 	pdata->port[2].pipe = -1;
 	spin_lock_init(&pdata->lpe_audio_slock);

 	platdev = platform_device_register_full(&pinfo);
 	if (IS_ERR(platdev)) {
 		ret = PTR_ERR(platdev);
 		DRM_ERROR("Failed to allocate LPE audio platform device\n");
 		goto err;
 	}

 	kfree(rsc);

 	pm_runtime_forbid(&platdev->dev);
 	pm_runtime_set_active(&platdev->dev);
 	pm_runtime_enable(&platdev->dev);

 	return platdev;

 err:
 	kfree(rsc);
 	kfree(pdata);
 	return ERR_PTR(ret);
 }

 static void lpe_audio_platdev_destroy(struct drm_i915_private *dev_priv)
 {
 	/* XXX Note that platform_device_register_full() allocates a dma_mask
 	 * and never frees it. We can't free it here as we cannot guarantee
 	 * this is the last reference (i.e. that the dma_mask will not be
 	 * used after our unregister). So ee choose to leak the sizeof(u64)
 	 * allocation here - it should be fixed in the platform_device rather
 	 * than us fiddle with its internals.
 	 */

 	platform_device_unregister(dev_priv->lpe_audio.platdev);
 }

 static void lpe_audio_irq_unmask(struct irq_data *d)
 {
 }

 static void lpe_audio_irq_mask(struct irq_data *d)
 {
 }

 static struct irq_chip lpe_audio_irqchip = {
 	.name = "hdmi_lpe_audio_irqchip",
 	.irq_mask = lpe_audio_irq_mask,
 	.irq_unmask = lpe_audio_irq_unmask,
 };

 static int lpe_audio_irq_init(struct drm_i915_private *dev_priv)
 {
 	int irq = dev_priv->lpe_audio.irq;

 	WARN_ON(!intel_irqs_enabled(dev_priv));
 	irq_set_chip_and_handler_name(irq,
 				&lpe_audio_irqchip,
 				handle_simple_irq,
 				"hdmi_lpe_audio_irq_handler");

 	return irq_set_chip_data(irq, dev_priv);
 }

 static bool lpe_audio_detect(struct drm_i915_private *dev_priv)
 {
 	int lpe_present = false;

 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
 		static const struct pci_device_id atom_hdaudio_ids[] = {
 			/* Baytrail */
 			{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0f04)},
 			/* Braswell */
 			{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x2284)},
 			{}
 		};

 		if (!pci_dev_present(atom_hdaudio_ids)) {
 			DRM_INFO("HDaudio controller not detected, using LPE audio instead\n");
 			lpe_present = true;
 		}
 	}
 	return lpe_present;
 }

 static int lpe_audio_setup(struct drm_i915_private *dev_priv)
 {
 	int ret;

 	dev_priv->lpe_audio.irq = irq_alloc_desc(0);
 	if (dev_priv->lpe_audio.irq < 0) {
 		DRM_ERROR("Failed to allocate IRQ desc: %d\n",
 			dev_priv->lpe_audio.irq);
 		ret = dev_priv->lpe_audio.irq;
 		goto err;
 	}

 	DRM_DEBUG("irq = %d\n", dev_priv->lpe_audio.irq);

 	ret = lpe_audio_irq_init(dev_priv);

 	if (ret) {
 		DRM_ERROR("Failed to initialize irqchip for lpe audio: %d\n",
 			ret);
 		goto err_free_irq;
 	}

 	dev_priv->lpe_audio.platdev = lpe_audio_platdev_create(dev_priv);

 	if (IS_ERR(dev_priv->lpe_audio.platdev)) {
 		ret = PTR_ERR(dev_priv->lpe_audio.platdev);
 		DRM_ERROR("Failed to create lpe audio platform device: %d\n",
 			ret);
 		goto err_free_irq;
 	}

 	/* enable chicken bit; at least this is required for Dell Wyse 3040
 	 * with DP outputs (but only sometimes by some reason!)
 	 */
 	I915_WRITE(VLV_AUD_CHICKEN_BIT_REG, VLV_CHICKEN_BIT_DBG_ENABLE);

 	return 0;
 err_free_irq:
 	irq_free_desc(dev_priv->lpe_audio.irq);
 err:
 	dev_priv->lpe_audio.irq = -1;
 	dev_priv->lpe_audio.platdev = NULL;
 	return ret;
 }

 /**
  * intel_lpe_audio_irq_handler() - forwards the LPE audio irq
  * @dev_priv: the i915 drm device private data
  *
  * the LPE Audio irq is forwarded to the irq handler registered by LPE audio
  * driver.
  */
 void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv)
 {
 	int ret;

 	if (!HAS_LPE_AUDIO(dev_priv))
 		return;

 	ret = generic_handle_irq(dev_priv->lpe_audio.irq);
 	if (ret)
 		DRM_ERROR_RATELIMITED("error handling LPE audio irq: %d\n",
 				ret);
 }

 /**
  * intel_lpe_audio_init() - detect and setup the bridge between HDMI LPE Audio
  * driver and i915
  * @dev_priv: the i915 drm device private data
  *
  * Return: 0 if successful. non-zero if detection or
  * llocation/initialization fails
  */
 int intel_lpe_audio_init(struct drm_i915_private *dev_priv)
 {
 	int ret = -ENODEV;

 	if (lpe_audio_detect(dev_priv)) {
 		ret = lpe_audio_setup(dev_priv);
 		if (ret < 0)
 			DRM_ERROR("failed to setup LPE Audio bridge\n");
 	}
 	return ret;
 }

 /**
  * intel_lpe_audio_teardown() - destroy the bridge between HDMI LPE
  * audio driver and i915
  * @dev_priv: the i915 drm device private data
  *
  * release all the resources for LPE audio <-> i915 bridge.
  */
 void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
 {
 	struct irq_desc *desc;

 	if (!HAS_LPE_AUDIO(dev_priv))
 		return;

 	desc = irq_to_desc(dev_priv->lpe_audio.irq);

 	lpe_audio_platdev_destroy(dev_priv);

 	irq_free_desc(dev_priv->lpe_audio.irq);
 }


 /**
  * intel_lpe_audio_notify() - notify lpe audio event
  * audio driver and i915
  * @dev_priv: the i915 drm device private data
  * @pipe: pipe
  * @port: port
  * @eld : ELD data
  * @ls_clock: Link symbol clock in kHz
  * @dp_output: Driving a DP output?
  *
  * Notify lpe audio driver of eld change.
  */
 void intel_lpe_audio_notify(struct drm_i915_private *dev_priv,
 			    enum pipe pipe, enum port port,
 			    const void *eld, int ls_clock, bool dp_output)
 {
 	unsigned long irqflags;
 	struct intel_hdmi_lpe_audio_pdata *pdata;
 	struct intel_hdmi_lpe_audio_port_pdata *ppdata;
 	u32 audio_enable;

 	if (!HAS_LPE_AUDIO(dev_priv))
 		return;

 	pdata = dev_get_platdata(&dev_priv->lpe_audio.platdev->dev);
 	ppdata = &pdata->port[port - PORT_B];

 	spin_lock_irqsave(&pdata->lpe_audio_slock, irqflags);

 	audio_enable = I915_READ(VLV_AUD_PORT_EN_DBG(port));

 	if (eld != NULL) {
 		memcpy(ppdata->eld, eld, HDMI_MAX_ELD_BYTES);
 		ppdata->pipe = pipe;
 		ppdata->ls_clock = ls_clock;
 		ppdata->dp_output = dp_output;

 		/* Unmute the amp for both DP and HDMI */
 		I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
 			   audio_enable & ~VLV_AMP_MUTE);
 	} else {
 		memset(ppdata->eld, 0, HDMI_MAX_ELD_BYTES);
 		ppdata->pipe = -1;
 		ppdata->ls_clock = 0;
 		ppdata->dp_output = false;

 		/* Mute the amp for both DP and HDMI */
 		I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
 			   audio_enable | VLV_AMP_MUTE);
 	}

 	if (pdata->notify_audio_lpe)
 		pdata->notify_audio_lpe(dev_priv->lpe_audio.platdev, port - PORT_B);

 	spin_unlock_irqrestore(&pdata->lpe_audio_slock, irqflags);
 }
	/*
	* Copyright © 2016 Intel Corporation
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	* IN THE SOFTWARE.
	*
	* Authors:
	* Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
	* Jerome Anand <jerome.anand@intel.com>
	* based on VED patches
	*
	*/

	/**
	* DOC: LPE Audio integration for HDMI or DP playback
	*
	* Motivation:
	* Atom platforms (e.g. valleyview and cherryTrail) integrates a DMA-based
	* interface as an alternative to the traditional HDaudio path. While this
	* mode is unrelated to the LPE aka SST audio engine, the documentation refers
	* to this mode as LPE so we keep this notation for the sake of consistency.
	*
	* The interface is handled by a separate standalone driver maintained in the
	* ALSA subsystem for simplicity. To minimize the interaction between the two
	* subsystems, a bridge is setup between the hdmi-lpe-audio and i915:
	* 1. Create a platform device to share MMIO/IRQ resources
	* 2. Make the platform device child of i915 device for runtime PM.
	* 3. Create IRQ chip to forward the LPE audio irqs.
	* the hdmi-lpe-audio driver probes the lpe audio device and creates a new
	* sound card
	*
	* Threats:
	* Due to the restriction in Linux platform device model, user need manually
	* uninstall the hdmi-lpe-audio driver before uninstalling i915 module,
	* otherwise we might run into use-after-free issues after i915 removes the
	* platform device: even though hdmi-lpe-audio driver is released, the modules
	* is still in "installed" status.
	*
	* Implementation:
	* The MMIO/REG platform resources are created according to the registers
	* specification.
	* When forwarding LPE audio irqs, the flow control handler selection depends
	* on the platform, for example on valleyview handle_simple_irq is enough.
	*
	*/

	#include <linux/acpi.h>
	#include <linux/device.h>
	#include <linux/pci.h>
	#include <linux/pm_runtime.h>

	#include "i915_drv.h"
	#include <linux/delay.h>
	#include <drm/intel_lpe_audio.h>

	#define HAS_LPE_AUDIO(dev_priv) ((dev_priv)->lpe_audio.platdev != NULL)

	static struct platform_device *
	lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
	{
	int ret;
	struct drm_device *dev = &dev_priv->drm;
	struct platform_device_info pinfo = {};
	struct resource *rsc;
	struct platform_device *platdev;
	struct intel_hdmi_lpe_audio_pdata *pdata;

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

	rsc = kcalloc(2, sizeof(*rsc), GFP_KERNEL);
	if (!rsc) {
	kfree(pdata);
	return ERR_PTR(-ENOMEM);
	}

	rsc[0].start = rsc[0].end = dev_priv->lpe_audio.irq;
	rsc[0].flags = IORESOURCE_IRQ;
	rsc[0].name = "hdmi-lpe-audio-irq";

	rsc[1].start = pci_resource_start(dev->pdev, 0) +
	I915_HDMI_LPE_AUDIO_BASE;
	rsc[1].end = pci_resource_start(dev->pdev, 0) +
	I915_HDMI_LPE_AUDIO_BASE + I915_HDMI_LPE_AUDIO_SIZE - 1;
	rsc[1].flags = IORESOURCE_MEM;
	rsc[1].name = "hdmi-lpe-audio-mmio";

	pinfo.parent = dev->dev;
	pinfo.name = "hdmi-lpe-audio";
	pinfo.id = -1;
	pinfo.res = rsc;
	pinfo.num_res = 2;
	pinfo.data = pdata;
	pinfo.size_data = sizeof(*pdata);
	pinfo.dma_mask = DMA_BIT_MASK(32);

	pdata->num_pipes = INTEL_INFO(dev_priv)->num_pipes;
	pdata->num_ports = IS_CHERRYVIEW(dev_priv) ? 3 : 2; /* B,C,D or B,C */
	pdata->port[0].pipe = -1;
	pdata->port[1].pipe = -1;
	pdata->port[2].pipe = -1;
	spin_lock_init(&pdata->lpe_audio_slock);

	platdev = platform_device_register_full(&pinfo);
	if (IS_ERR(platdev)) {
	ret = PTR_ERR(platdev);
	DRM_ERROR("Failed to allocate LPE audio platform device\n");
	goto err;
	}

	kfree(rsc);

	pm_runtime_forbid(&platdev->dev);
	pm_runtime_set_active(&platdev->dev);
	pm_runtime_enable(&platdev->dev);

	return platdev;

	err:
	kfree(rsc);
	kfree(pdata);
	return ERR_PTR(ret);
	}

	static void lpe_audio_platdev_destroy(struct drm_i915_private *dev_priv)
	{
	/* XXX Note that platform_device_register_full() allocates a dma_mask
	* and never frees it. We can't free it here as we cannot guarantee
	* this is the last reference (i.e. that the dma_mask will not be
	* used after our unregister). So ee choose to leak the sizeof(u64)
	* allocation here - it should be fixed in the platform_device rather
	* than us fiddle with its internals.
	*/

	platform_device_unregister(dev_priv->lpe_audio.platdev);
	}

	static void lpe_audio_irq_unmask(struct irq_data *d)
	{
	}

	static void lpe_audio_irq_mask(struct irq_data *d)
	{
	}

	static struct irq_chip lpe_audio_irqchip = {
	.name = "hdmi_lpe_audio_irqchip",
	.irq_mask = lpe_audio_irq_mask,
	.irq_unmask = lpe_audio_irq_unmask,
	};

	static int lpe_audio_irq_init(struct drm_i915_private *dev_priv)
	{
	int irq = dev_priv->lpe_audio.irq;

	WARN_ON(!intel_irqs_enabled(dev_priv));
	irq_set_chip_and_handler_name(irq,
	&lpe_audio_irqchip,
	handle_simple_irq,
	"hdmi_lpe_audio_irq_handler");

	return irq_set_chip_data(irq, dev_priv);
	}

	static bool lpe_audio_detect(struct drm_i915_private *dev_priv)
	{
	int lpe_present = false;

	if (IS_VALLEYVIEW(dev_priv) \|\| IS_CHERRYVIEW(dev_priv)) {
	static const struct pci_device_id atom_hdaudio_ids[] = {
	/* Baytrail */
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0f04)},
	/* Braswell */
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x2284)},
	{}
	};

	if (!pci_dev_present(atom_hdaudio_ids)) {
	DRM_INFO("HDaudio controller not detected, using LPE audio instead\n");
	lpe_present = true;
	}
	}
	return lpe_present;
	}

	static int lpe_audio_setup(struct drm_i915_private *dev_priv)
	{
	int ret;

	dev_priv->lpe_audio.irq = irq_alloc_desc(0);
	if (dev_priv->lpe_audio.irq < 0) {
	DRM_ERROR("Failed to allocate IRQ desc: %d\n",
	dev_priv->lpe_audio.irq);
	ret = dev_priv->lpe_audio.irq;
	goto err;
	}

	DRM_DEBUG("irq = %d\n", dev_priv->lpe_audio.irq);

	ret = lpe_audio_irq_init(dev_priv);

	if (ret) {
	DRM_ERROR("Failed to initialize irqchip for lpe audio: %d\n",
	ret);
	goto err_free_irq;
	}

	dev_priv->lpe_audio.platdev = lpe_audio_platdev_create(dev_priv);

	if (IS_ERR(dev_priv->lpe_audio.platdev)) {
	ret = PTR_ERR(dev_priv->lpe_audio.platdev);
	DRM_ERROR("Failed to create lpe audio platform device: %d\n",
	ret);
	goto err_free_irq;
	}

	/* enable chicken bit; at least this is required for Dell Wyse 3040
	* with DP outputs (but only sometimes by some reason!)
	*/
	I915_WRITE(VLV_AUD_CHICKEN_BIT_REG, VLV_CHICKEN_BIT_DBG_ENABLE);

	return 0;
	err_free_irq:
	irq_free_desc(dev_priv->lpe_audio.irq);
	err:
	dev_priv->lpe_audio.irq = -1;
	dev_priv->lpe_audio.platdev = NULL;
	return ret;
	}

	/**
	* intel_lpe_audio_irq_handler() - forwards the LPE audio irq
	* @dev_priv: the i915 drm device private data
	*
	* the LPE Audio irq is forwarded to the irq handler registered by LPE audio
	* driver.
	*/
	void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv)
	{
	int ret;

	if (!HAS_LPE_AUDIO(dev_priv))
	return;

	ret = generic_handle_irq(dev_priv->lpe_audio.irq);
	if (ret)
	DRM_ERROR_RATELIMITED("error handling LPE audio irq: %d\n",
	ret);
	}

	/**
	* intel_lpe_audio_init() - detect and setup the bridge between HDMI LPE Audio
	* driver and i915
	* @dev_priv: the i915 drm device private data
	*
	* Return: 0 if successful. non-zero if detection or
	* llocation/initialization fails
	*/
	int intel_lpe_audio_init(struct drm_i915_private *dev_priv)
	{
	int ret = -ENODEV;

	if (lpe_audio_detect(dev_priv)) {
	ret = lpe_audio_setup(dev_priv);
	if (ret < 0)
	DRM_ERROR("failed to setup LPE Audio bridge\n");
	}
	return ret;
	}

	/**
	* intel_lpe_audio_teardown() - destroy the bridge between HDMI LPE
	* audio driver and i915
	* @dev_priv: the i915 drm device private data
	*
	* release all the resources for LPE audio <-> i915 bridge.
	*/
	void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
	{
	struct irq_desc *desc;

	if (!HAS_LPE_AUDIO(dev_priv))
	return;

	desc = irq_to_desc(dev_priv->lpe_audio.irq);

	lpe_audio_platdev_destroy(dev_priv);

	irq_free_desc(dev_priv->lpe_audio.irq);
	}


	/**
	* intel_lpe_audio_notify() - notify lpe audio event
	* audio driver and i915
	* @dev_priv: the i915 drm device private data
	* @pipe: pipe
	* @port: port
	* @eld : ELD data
	* @ls_clock: Link symbol clock in kHz
	* @dp_output: Driving a DP output?
	*
	* Notify lpe audio driver of eld change.
	*/
	void intel_lpe_audio_notify(struct drm_i915_private *dev_priv,
	enum pipe pipe, enum port port,
	const void *eld, int ls_clock, bool dp_output)
	{
	unsigned long irqflags;
	struct intel_hdmi_lpe_audio_pdata *pdata;
	struct intel_hdmi_lpe_audio_port_pdata *ppdata;
	u32 audio_enable;

	if (!HAS_LPE_AUDIO(dev_priv))
	return;

	pdata = dev_get_platdata(&dev_priv->lpe_audio.platdev->dev);
	ppdata = &pdata->port[port - PORT_B];

	spin_lock_irqsave(&pdata->lpe_audio_slock, irqflags);

	audio_enable = I915_READ(VLV_AUD_PORT_EN_DBG(port));

	if (eld != NULL) {
	memcpy(ppdata->eld, eld, HDMI_MAX_ELD_BYTES);
	ppdata->pipe = pipe;
	ppdata->ls_clock = ls_clock;
	ppdata->dp_output = dp_output;

	/* Unmute the amp for both DP and HDMI */
	I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
	audio_enable & ~VLV_AMP_MUTE);
	} else {
	memset(ppdata->eld, 0, HDMI_MAX_ELD_BYTES);
	ppdata->pipe = -1;
	ppdata->ls_clock = 0;
	ppdata->dp_output = false;

	/* Mute the amp for both DP and HDMI */
	I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
	audio_enable \| VLV_AMP_MUTE);
	}

	if (pdata->notify_audio_lpe)
	pdata->notify_audio_lpe(dev_priv->lpe_audio.platdev, port - PORT_B);

	spin_unlock_irqrestore(&pdata->lpe_audio_slock, irqflags);
	}