Re: [PATCH v2 2/2] drm/i915/guc: Reset GuC and retry on firmware load failure

[Yu Dai <yu.dai@intel.com>]

LGTM. Reviewed-by: Alex Dai <yu.dai@intel.com>

On 03/08/2016 03:38 AM, Arun Siluvery wrote:
> Due to timing issues in the HW some of the status bits required for GuC
> authentication doesn't get set occassionally, when that happens, GuC cannot
> be initialized and we will be left with a wedged GPU. The WA suggested is
> to perform a soft reset of GuC and attempt to reload the fw again for few
> times before giving up.
>
> As the failure is dependent on timing, tests performed by triggering manual
> full gpu reset (i915_wedged) showed that we could sometimes hit this after
> several thousand iterations but sometimes tests ran even longer without any
> issues. Reset and reload mechanism proved helpful when we indeed hit fw
> load failure so it is better to include this to improve driver stability.
>
> This change implements the following WA,
>
> WaEnableuKernelHeaderValidFix:skl,bxt
> WaEnableGuCBootHashCheckNotSet:skl,bxt
>
> Cc: Dave Gordon <david.s.gordon@intel.com>
> Cc: Alex Dai <yu.dai@intel.com>
> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h         |  1 +
>   drivers/gpu/drm/i915/i915_guc_reg.h     |  1 +
>   drivers/gpu/drm/i915/i915_reg.h         |  1 +
>   drivers/gpu/drm/i915/intel_guc_loader.c | 49 +++++++++++++++++++++++++++++++--
>   drivers/gpu/drm/i915/intel_uncore.c     | 19 +++++++++++++
>   5 files changed, 69 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index f37ac12..0df7c82 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2757,6 +2757,7 @@ extern long i915_compat_ioctl(struct file *filp, unsigned int cmd,
>   extern int intel_gpu_reset(struct drm_device *dev);
>   extern bool intel_has_gpu_reset(struct drm_device *dev);
>   extern int i915_reset(struct drm_device *dev);
> +extern int intel_guc_reset(struct drm_i915_private *dev_priv);
>   extern unsigned long i915_chipset_val(struct drm_i915_private *dev_priv);
>   extern unsigned long i915_mch_val(struct drm_i915_private *dev_priv);
>   extern unsigned long i915_gfx_val(struct drm_i915_private *dev_priv);
> diff --git a/drivers/gpu/drm/i915/i915_guc_reg.h b/drivers/gpu/drm/i915/i915_guc_reg.h
> index e4ba582..94ceee5 100644
> --- a/drivers/gpu/drm/i915/i915_guc_reg.h
> +++ b/drivers/gpu/drm/i915/i915_guc_reg.h
> @@ -27,6 +27,7 @@
>   /* Definitions of GuC H/W registers, bits, etc */
>   
>   #define GUC_STATUS			_MMIO(0xc000)
> +#define   GS_MIA_IN_RESET		(1 << 0)
>   #define   GS_BOOTROM_SHIFT		1
>   #define   GS_BOOTROM_MASK		  (0x7F << GS_BOOTROM_SHIFT)
>   #define   GS_BOOTROM_RSA_FAILED		  (0x50 << GS_BOOTROM_SHIFT)
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 7dfc400..48a23de 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -164,6 +164,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
>   #define  GEN6_GRDOM_RENDER		(1 << 1)
>   #define  GEN6_GRDOM_MEDIA		(1 << 2)
>   #define  GEN6_GRDOM_BLT			(1 << 3)
> +#define  GEN9_GRDOM_GUC			(1 << 5)
>   
>   #define RING_PP_DIR_BASE(ring)		_MMIO((ring)->mmio_base+0x228)
>   #define RING_PP_DIR_BASE_READ(ring)	_MMIO((ring)->mmio_base+0x518)
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index 82a3c03..f9cb814 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -353,6 +353,24 @@ static int guc_ucode_xfer(struct drm_i915_private *dev_priv)
>   	return ret;
>   }
>   
> +static int i915_reset_guc(struct drm_i915_private *dev_priv)
> +{
> +	int ret;
> +	u32 guc_status;
> +
> +	ret = intel_guc_reset(dev_priv);
> +	if (ret) {
> +		DRM_ERROR("GuC reset failed, ret = %d\n", ret);
> +		return ret;
> +	}
> +
> +	guc_status = I915_READ(GUC_STATUS);
> +	WARN(!(guc_status & GS_MIA_IN_RESET),
> +	     "GuC status: 0x%x, MIA core expected to be in reset\n", guc_status);
> +
> +	return ret;
> +}
> +
>   /**
>    * intel_guc_ucode_load() - load GuC uCode into the device
>    * @dev:	drm device
> @@ -417,9 +435,36 @@ int intel_guc_ucode_load(struct drm_device *dev)
>   	if (err)
>   		goto fail;
>   
> +	/*
> +	 * WaEnableuKernelHeaderValidFix:skl,bxt
> +	 * For BXT, this is only upto B0 but below WA is required for later
> +	 * steppings also so this is extended as well.
> +	 */
> +	/* WaEnableGuCBootHashCheckNotSet:skl,bxt */
>   	err = guc_ucode_xfer(dev_priv);
> -	if (err)
> -		goto fail;
> +	if (err) {
> +		int retries = 3;
> +
> +		DRM_ERROR("GuC fw load failed, err=%d, attempting reset and retry\n", err);
> +
> +		while (retries--) {
> +			err = i915_reset_guc(dev_priv);
> +			if (err)
> +				break;
> +
> +			err = guc_ucode_xfer(dev_priv);
> +			if (!err) {
> +				DRM_DEBUG_DRIVER("GuC fw reload succeeded after reset\n");
> +				break;
> +			}
> +			DRM_DEBUG_DRIVER("GuC fw reload retries left: %d\n", retries);
> +		}
> +
> +		if (err) {
> +			DRM_ERROR("GuC fw reload attempt failed, ret=%d\n", err);
> +			goto fail;
> +		}
> +	}
>   
>   	guc_fw->guc_fw_load_status = GUC_FIRMWARE_SUCCESS;
>   
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index 80e38d5..92be76a 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -1647,6 +1647,25 @@ bool intel_has_gpu_reset(struct drm_device *dev)
>   	return intel_get_gpu_reset(dev) != NULL;
>   }
>   
> +int intel_guc_reset(struct drm_i915_private *dev_priv)
> +{
> +	int ret;
> +	unsigned long irqflags;
> +
> +	if (!i915.enable_guc_submission)
> +		return -EINVAL;
> +
> +	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
> +	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
> +
> +	ret = gen6_domain_reset(dev_priv, GEN9_GRDOM_GUC);
> +
> +	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
> +	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
> +
> +	return ret;
> +}
> +
>   bool intel_uncore_unclaimed_mmio(struct drm_i915_private *dev_priv)
>   {
>   	return check_for_unclaimed_mmio(dev_priv);

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