[alsa-devel] [RFC PATCH v3 1/7] drm/i915: setup bridge for HDMI LPE audio driver

Ville Syrjälä ville.syrjala at linux.intel.com
Thu Nov 24 14:31:54 CET 2016


On Fri, Nov 25, 2016 at 05:25:42AM +0530, Jerome Anand wrote:
> Enable support for HDMI LPE audio mode on Baytrail and
> Cherrytrail when HDaudio controller is not detected
> 
> Setup minimum required resources during i915_driver_load:
> 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 HDMI LPE audio irqs.
> 
> HDMI LPE audio driver (a standalone sound driver) probes the
> LPE audio device and creates a new sound card.
> 
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
> Signed-off-by: Jerome Anand <jerome.anand at intel.com>
> ---
>  Documentation/gpu/i915.rst             |   9 +
>  drivers/gpu/drm/i915/Makefile          |   3 +
>  drivers/gpu/drm/i915/i915_drv.c        |   8 +-
>  drivers/gpu/drm/i915/i915_drv.h        |  15 ++
>  drivers/gpu/drm/i915/i915_irq.c        |  29 +++
>  drivers/gpu/drm/i915/i915_reg.h        |   3 +
>  drivers/gpu/drm/i915/intel_lpe_audio.c | 369 +++++++++++++++++++++++++++++++++
>  include/drm/intel_lpe_audio.h          |  45 ++++
>  8 files changed, 479 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/intel_lpe_audio.c
>  create mode 100644 include/drm/intel_lpe_audio.h
> 
> diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst
> index 117d2ab..a671eee 100644
> --- a/Documentation/gpu/i915.rst
> +++ b/Documentation/gpu/i915.rst
> @@ -213,6 +213,15 @@ Video BIOS Table (VBT)
>  .. kernel-doc:: drivers/gpu/drm/i915/intel_vbt_defs.h
>     :internal:
>  
> +intel hdmi lpe audio support
> +----------------------------
> +
> +.. kernel-doc:: drivers/gpu/drm/i915/intel_lpe_audio.c
> +   :doc:  LPE Audio integration for HDMI or DP playback
> +
> +.. kernel-doc:: drivers/gpu/drm/i915/intel_lpe_audio.c
> +   :internal:
> +
>  Memory Management and Command Submission
>  ========================================
>  
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 580602d..3a2369c 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -126,6 +126,9 @@ i915-y += intel_gvt.o
>  include $(src)/gvt/Makefile
>  endif
>  
> +# LPE Audio for VLV and CHT
> +i915-y += intel_lpe_audio.o
> +
>  obj-$(CONFIG_DRM_I915) += i915.o
>  
>  CFLAGS_i915_trace_points.o := -I$(src)
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index b893e67..93811ed 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1144,7 +1144,8 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
>  	if (IS_GEN5(dev_priv))
>  		intel_gpu_ips_init(dev_priv);
>  
> -	i915_audio_component_init(dev_priv);
> +	if (intel_lpe_audio_init(dev_priv) < 0)
> +		i915_audio_component_init(dev_priv);
>  
>  	/*
>  	 * Some ports require correctly set-up hpd registers for detection to
> @@ -1162,7 +1163,10 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
>   */
>  static void i915_driver_unregister(struct drm_i915_private *dev_priv)
>  {
> -	i915_audio_component_cleanup(dev_priv);
> +	if (HAS_LPE_AUDIO(dev_priv))
> +		intel_lpe_audio_teardown(dev_priv);
> +	else
> +		i915_audio_component_cleanup(dev_priv);
>  
>  	intel_gpu_ips_teardown();
>  	acpi_video_unregister();
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 970e50b..2a79048 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2284,6 +2284,12 @@ struct drm_i915_private {
>  	/* Used to save the pipe-to-encoder mapping for audio */
>  	struct intel_encoder *av_enc_map[I915_MAX_PIPES];
>  
> +	/* necessary resource sharing with HDMI LPE audio driver. */
> +	struct {
> +		struct platform_device *platdev;
> +		int	irq;
> +	} lpe_audio;
> +
>  	/*
>  	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
>  	 * will be rejected. Instead look for a better place.
> @@ -2773,6 +2779,8 @@ intel_info(const struct drm_i915_private *dev_priv)
>  
>  #define HAS_POOLED_EU(dev_priv)	((dev_priv)->info.has_pooled_eu)
>  
> +#define HAS_LPE_AUDIO(dev_priv) ((dev_priv)->lpe_audio.platdev != NULL)
> +
>  #define INTEL_PCH_DEVICE_ID_MASK		0xff00
>  #define INTEL_PCH_IBX_DEVICE_ID_TYPE		0x3b00
>  #define INTEL_PCH_CPT_DEVICE_ID_TYPE		0x1c00
> @@ -3547,6 +3555,13 @@ extern int i915_restore_state(struct drm_device *dev);
>  void i915_setup_sysfs(struct drm_i915_private *dev_priv);
>  void i915_teardown_sysfs(struct drm_i915_private *dev_priv);
>  
> +/* i915_lpe_audio.c */
> +int  intel_lpe_audio_init(struct drm_i915_private *dev_priv);
> +int  intel_lpe_audio_setup(struct drm_i915_private *dev_priv);
> +void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv);
> +void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv);
> +bool intel_lpe_audio_detect(struct drm_i915_private *dev_priv);
> +
>  /* intel_i2c.c */
>  extern int intel_setup_gmbus(struct drm_device *dev);
>  extern void intel_teardown_gmbus(struct drm_device *dev);
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 07ca71c..6c98b28 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1894,6 +1894,15 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
>  		valleyview_pipestat_irq_ack(dev_priv, iir, pipe_stats);
>  
>  		/*
> +		 * LPE audio interrupts are only enabled on Baytrail and
> +		 * CherryView platforms without HDaudio
> +		 */
> +		if (iir & (I915_LPE_PIPE_A_INTERRUPT |
> +			   I915_LPE_PIPE_B_INTERRUPT |
> +			   I915_LPE_PIPE_C_INTERRUPT))

No pipe C on vlv.

> +			intel_lpe_audio_irq_handler(dev_priv);
> +
> +		/*
>  		 * VLV_IIR is single buffered, and reflects the level
>  		 * from PIPESTAT/PORT_HOTPLUG_STAT, hence clear it last.
>  		 */
> @@ -1974,6 +1983,15 @@ static irqreturn_t cherryview_irq_handler(int irq, void *arg)
>  		valleyview_pipestat_irq_ack(dev_priv, iir, pipe_stats);
>  
>  		/*
> +		 * LPE audio interrupts are only enabled on Baytrail and
> +		 * CherryView platforms without HDaudio
> +		 */
> +		if (iir & (I915_LPE_PIPE_A_INTERRUPT |
> +			   I915_LPE_PIPE_B_INTERRUPT |
> +			   I915_LPE_PIPE_C_INTERRUPT))
> +			intel_lpe_audio_irq_handler(dev_priv);
> +
> +		/*
>  		 * VLV_IIR is single buffered, and reflects the level
>  		 * from PIPESTAT/PORT_HOTPLUG_STAT, hence clear it last.
>  		 */
> @@ -2930,6 +2948,17 @@ static void vlv_display_irq_postinstall(struct drm_i915_private *dev_priv)
>  
>  	WARN_ON(dev_priv->irq_mask != ~0);
>  
> +	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {

This is vlv/chv specific code, so no need to check for it.

> +		/* add interrupt masks unconditially here, the actual unmask
> +		 * will take place only if the LPE_AUDIO mode is detected
> +		 */
> +		u32 val = (I915_LPE_PIPE_A_INTERRUPT |
> +			I915_LPE_PIPE_B_INTERRUPT |
> +			I915_LPE_PIPE_C_INTERRUPT);
> +
> +		enable_mask |= val;
> +	}
> +
>  	dev_priv->irq_mask = ~enable_mask;
>  
>  	GEN5_IRQ_INIT(VLV_, dev_priv->irq_mask, enable_mask);
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index fcad8fa..6b16ed0 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2395,6 +2395,9 @@ enum skl_disp_power_wells {
>  #define I915_ASLE_INTERRUPT				(1<<0)
>  #define I915_BSD_USER_INTERRUPT				(1<<25)
>  
> +#define I915_HDMI_LPE_AUDIO_BASE	(VLV_DISPLAY_BASE + 0x65000)
> +#define I915_HDMI_LPE_AUDIO_SIZE	0x1000
> +
>  #define GEN6_BSD_RNCID			_MMIO(0x12198)
>  
>  #define GEN7_FF_THREAD_MODE		_MMIO(0x20a0)
> diff --git a/drivers/gpu/drm/i915/intel_lpe_audio.c b/drivers/gpu/drm/i915/intel_lpe_audio.c
> new file mode 100644
> index 0000000..5335fc6
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_lpe_audio.c
> @@ -0,0 +1,369 @@
> +/*
> + * 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 at linux.intel.com>
> + *    Jerome Anand <jerome.anand at 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 "i915_drv.h"
> +#include <linux/delay.h>
> +#include <drm/intel_lpe_audio.h>
> +
> +static struct platform_device*
> +lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
> +{
> +	struct drm_device *dev = &dev_priv->drm;
> +	int ret;
> +	struct resource rsc[2] = {};
> +	struct platform_device *platdev;
> +	u64 *dma_mask;
> +	struct intel_hdmi_lpe_audio_pdata *pdata;
> +
> +	if (dev_priv->lpe_audio.irq < 0)
> +		return ERR_PTR(-EINVAL);
> +
> +	platdev = platform_device_alloc("hdmi-lpe-audio", -1);
> +	if (!platdev) {
> +		ret = -ENOMEM;
> +		DRM_ERROR("Failed to allocate LPE audio platform device\n");
> +		goto err;
> +	}
> +
> +	/* to work-around check_addr in nommu_map_sg() */
> +	dma_mask = kmalloc(sizeof(*platdev->dev.dma_mask), GFP_KERNEL);
> +	if (!dma_mask) {
> +		ret = -ENOMEM;
> +		DRM_ERROR("Failed to allocate dma_mask\n");
> +		goto err_put_dev;
> +	}
> +	*dma_mask = DMA_BIT_MASK(32);
> +	platdev->dev.dma_mask = dma_mask;
> +	platdev->dev.coherent_dma_mask = *dma_mask;
> +
> +	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";
> +
> +	ret = platform_device_add_resources(platdev, rsc, 2);
> +	if (ret) {
> +		DRM_ERROR("Failed to add resource for platform device: %d\n",
> +			ret);
> +		goto err_put_dev;
> +	}
> +
> +	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
> +
> +	if (pdata == NULL) {
> +		ret = -ENOMEM;
> +		goto err_put_dev;
> +	}
> +	platdev->dev.platform_data = pdata;
> +	spin_lock_init(&pdata->lpe_audio_slock);
> +
> +	/* for LPE audio driver's runtime-PM */
> +	platdev->dev.parent = dev->dev;
> +	ret = platform_device_add(platdev);
> +	if (ret) {
> +		DRM_ERROR("Failed to add LPE audio platform device: %d\n",
> +			ret);
> +		goto err_put_dev;
> +	}
> +
> +	return platdev;
> +err_put_dev:
> +	platform_device_put(platdev);
> +	kfree(dma_mask);
> +err:
> +	return ERR_PTR(ret);
> +}
> +
> +static void lpe_audio_platdev_destroy(struct drm_i915_private *dev_priv)
> +{
> +	if (!HAS_LPE_AUDIO(dev_priv))
> +		return;
> +	platform_device_unregister(dev_priv->lpe_audio.platdev);
> +	kfree(dev_priv->lpe_audio.platdev->dev.dma_mask);
> +}
> +
> +static void lpe_audio_irq_unmask(struct irq_data *d)
> +{
> +	struct drm_device *dev = d->chip_data;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	unsigned long irqflags;
> +	u32 val = (I915_LPE_PIPE_A_INTERRUPT |
> +		I915_LPE_PIPE_B_INTERRUPT |
> +		I915_LPE_PIPE_C_INTERRUPT);

No pipe C on vlv.

> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +
> +	/*
> +	 * VLV_IER is already set in the vlv_display_postinstall(),
> +	 * we only change VLV_IIR and VLV_IMR
> +	 */
> +	dev_priv->irq_mask &= ~val;
> +	I915_WRITE(VLV_IIR, val);
> +	I915_WRITE(VLV_IIR, val);
> +	I915_WRITE(VLV_IMR, dev_priv->irq_mask);
> +	POSTING_READ(VLV_IMR);
> +
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
> +static void lpe_audio_irq_mask(struct irq_data *d)
> +{
> +	struct drm_device *dev = d->chip_data;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	unsigned long irqflags;
> +	u32 val = (I915_LPE_PIPE_A_INTERRUPT |
> +		I915_LPE_PIPE_B_INTERRUPT |
> +		I915_LPE_PIPE_C_INTERRUPT);

ditto

> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +
> +	/*
> +	 * VLV_IER is already set in the vlv_display_postinstall(),
> +	 * we only change VLV_IIR and VLV_IMR
> +	 */
> +	dev_priv->irq_mask |= val;
> +	I915_WRITE(VLV_IMR, dev_priv->irq_mask);
> +	I915_WRITE(VLV_IIR, val);
> +	I915_WRITE(VLV_IIR, val);
> +	POSTING_READ(VLV_IIR);
> +
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
> +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->drm);

Just pass dev_priv as the chip data.

> +}
> +
> +/**
> + * 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;
> +
> +	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_detect() - check & setup lpe audio if present
> + * @dev_priv: the i915 drm device private data
> + *
> + * Detect if lpe audio is present
> + *
> + * Return: true if lpe audio present else Return = false
> + */
> +bool intel_lpe_audio_detect(struct drm_i915_private *dev_priv)
> +{
> +	int lpe_present = false;
> +
> +	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {

Could avoid indenting the whole thig by reversing this test and doing an
early return.

> +		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)},
> +			{}
> +		};

IIRC I asked if we could use a HDA class match instead. But I forget
what the answer was. No presumably?

> +
> +		if (!pci_dev_present(atom_hdaudio_ids)) {
> +			DRM_INFO("%s%s\n", "HDaudio controller not detected,",
> +				"using LPE audio instead\n");
> +			lpe_present = true;
> +		}
> +	}
> +	return lpe_present;
> +}
> +
> +/**
> + * intel_lpe_audio_setup() - setup the bridge between HDMI LPE Audio
> + * driver and i915
> + * @dev_priv: the i915 drm device private data
> + *
> + * set up the minimum required resources for the bridge: irq chip,
> + * platform resource and platform device. i915 device is set as parent
> + * of the new platform device.
> + *
> + * Return: 0 if successful. non-zero if allocation/initialization fails
> + */
> +int intel_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;
> +	}
> +
> +	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_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 (intel_lpe_audio_detect(dev_priv)) {
> +		ret = intel_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)
> +{
> +	unsigned long irqflags;
> +	struct irq_desc *desc;
> +
> +	desc = (dev_priv->lpe_audio.irq >= 0) ?
> +		irq_to_desc(dev_priv->lpe_audio.irq) : NULL;

Why not just "if (lpe not initialized) return;" ?

> +
> +	/**
> +	 * mask LPE audio irq before destroying
> +	 */
> +	if (desc)
> +		lpe_audio_irq_mask(&desc->irq_data);

This seems racy. Should unregister the platdev first I think,

> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +
> +	lpe_audio_platdev_destroy(dev_priv);
> +
> +	if (desc)
> +		irq_free_desc(dev_priv->lpe_audio.irq);
> +
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> diff --git a/include/drm/intel_lpe_audio.h b/include/drm/intel_lpe_audio.h
> new file mode 100644
> index 0000000..a64c449
> --- /dev/null
> +++ b/include/drm/intel_lpe_audio.h
> @@ -0,0 +1,45 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef _INTEL_LPE_AUDIO_H_
> +#define _INTEL_LPE_AUDIO_H_
> +
> +#include <linux/types.h>
> +
> +#define HDMI_MAX_ELD_BYTES	128
> +
> +struct intel_hdmi_lpe_audio_eld {
> +	int port_id;
> +	unsigned char eld_data[HDMI_MAX_ELD_BYTES];
> +};
> +
> +struct intel_hdmi_lpe_audio_pdata {
> +	bool notify_pending;
> +	int tmds_clock_speed;
> +	bool hdmi_connected;
> +	struct intel_hdmi_lpe_audio_eld eld;
> +	void (*notify_audio_lpe)(void *audio_ptr);
> +	spinlock_t lpe_audio_slock;
> +};
> +
> +#endif /* _I915_LPE_AUDIO_H_ */
> -- 
> 2.9.3

-- 
Ville Syrjälä
Intel OTC


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