[Intel-gfx] [CI 1/2] drm/i915/guc: Enable send function only after successful init

[Chris Wilson]

On Tue, May 02, 2017 at 10:32:42AM +0000, Michal Wajdeczko wrote:
> It is safer to setup valid send function after successful GuC
> hardware initialization. In addition we prepare placeholder
> where we can setup any alternate GuC communication mechanism.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_uc.c | 27 ++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_uc.h |  1 +
>  2 files changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_uc.c b/drivers/gpu/drm/i915/intel_uc.c
> index 900e376..5957a95 100644
> --- a/drivers/gpu/drm/i915/intel_uc.c
> +++ b/drivers/gpu/drm/i915/intel_uc.c
> @@ -99,7 +99,7 @@ void intel_uc_init_early(struct drm_i915_private *dev_priv)
>  	struct intel_guc *guc = &dev_priv->guc;
>  
>  	mutex_init(&guc->send_mutex);
> -	guc->send = intel_guc_send_mmio;
> +	guc->send = intel_guc_send_nop;
>  }
>  
>  static void fetch_uc_fw(struct drm_i915_private *dev_priv,
> @@ -252,13 +252,27 @@ void intel_uc_fini_fw(struct drm_i915_private *dev_priv)
>  	__intel_uc_fw_fini(&dev_priv->huc.fw);
>  }
>  
> +static int guc_enable_communication(struct intel_guc *guc)
> +{
> +	/* XXX: placeholder for alternate setup */
> +	guc->send = intel_guc_send_mmio;
> +	return 0;
> +}
> +
> +static void guc_disable_communication(struct intel_guc *guc)
> +{
> +	guc->send = intel_guc_send_nop;
> +}
> +
>  int intel_uc_init_hw(struct drm_i915_private *dev_priv)
>  {
> +	struct intel_guc *guc = &dev_priv->guc;
>  	int ret, attempts;
>  
>  	if (!i915.enable_guc_loading)
>  		return 0;
>  
> +	guc_disable_communication(guc);
>  	gen9_reset_guc_interrupts(dev_priv);
>  
>  	/* We need to notify the guc whenever we change the GGTT */
> @@ -308,6 +322,10 @@ int intel_uc_init_hw(struct drm_i915_private *dev_priv)
>  	if (ret)
>  		goto err_submission;
>  
> +	ret = guc_enable_communication(guc);
> +	if (ret)
> +		goto err_submission;
> +
>  	intel_guc_auth_huc(dev_priv);
>  	if (i915.enable_guc_submission) {
>  		if (i915.guc_log_level >= 0)
> @@ -330,6 +348,7 @@ int intel_uc_init_hw(struct drm_i915_private *dev_priv)
>  	 * marks the GPU as wedged until reset).
>  	 */
>  err_interrupts:
> +	guc_disable_communication(guc);
>  	gen9_disable_guc_interrupts(dev_priv);
>  err_submission:
>  	if (i915.enable_guc_submission)
> @@ -364,6 +383,12 @@ void intel_uc_fini_hw(struct drm_i915_private *dev_priv)
>  	i915_ggtt_disable_guc(dev_priv);
>  }
>  
> +int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len)
> +{
> +	WARN(1, "Unexpected send: action=%#x\n", *action);
> +	return -ENOSYS;
> +}
> +
>  /*
>   * This function implements the MMIO based host to GuC interface.
>   */
> diff --git a/drivers/gpu/drm/i915/intel_uc.h b/drivers/gpu/drm/i915/intel_uc.h
> index 2f0229d..1e0eecd 100644
> --- a/drivers/gpu/drm/i915/intel_uc.h
> +++ b/drivers/gpu/drm/i915/intel_uc.h
> @@ -227,6 +227,7 @@ void intel_uc_fini_fw(struct drm_i915_private *dev_priv);
>  int intel_uc_init_hw(struct drm_i915_private *dev_priv);
>  void intel_uc_fini_hw(struct drm_i915_private *dev_priv);
>  int intel_guc_sample_forcewake(struct intel_guc *guc);
> +int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len);

Was there a reason for exporting the nop? Its a purely internal BUG_ON()
function that should only be set when disabling the guc. Afaict, it
should be private.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre