[Intel-gfx] [PATCH v2 2/3] drm/i915/bxt: Wait for PHY1 GRC done if PHY0 was already enabled

[Ville Syrjälä]

On Thu, Apr 21, 2016 at 07:19:21PM +0300, Imre Deak wrote:
> If we skipped PHY0 initialization because it was already enabled by
> BIOS, we still have to wait for the PHY1 GRC calibration as that is
> done as part of the PHY0 init.
> 
> v2:
> - Use the actual PHY index in the debug message in
>   broxton_phy_wait_grc_done() (Ville)
> 
> CC: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 943aa93..c836f21 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1760,6 +1760,13 @@ static u32 broxton_get_grc(struct drm_i915_private *dev_priv, enum dpio_phy phy)
>  	return (val & GRC_CODE_MASK) >> GRC_CODE_SHIFT;
>  }
>  
> +static void broxton_phy_wait_grc_done(struct drm_i915_private *dev_priv,
> +				      enum dpio_phy phy)
> +{
> +	if (wait_for(I915_READ(BXT_PORT_REF_DW3(phy)) & GRC_DONE, 10))
> +		DRM_ERROR("timeout waiting for PHY%d GRC\n", phy);
> +}
> +
>  static void broxton_phy_init(struct drm_i915_private *dev_priv,
>  			     enum dpio_phy phy)
>  {
> @@ -1863,9 +1870,7 @@ static void broxton_phy_init(struct drm_i915_private *dev_priv,
>  		 * the corresponding calibrated value from PHY1, and disable
>  		 * the automatic calibration on PHY0.
>  		 */
> -		if (wait_for(I915_READ(BXT_PORT_REF_DW3(DPIO_PHY1)) & GRC_DONE,
> -			     10))
> -			DRM_ERROR("timeout waiting for PHY1 GRC\n");
> +		broxton_phy_wait_grc_done(dev_priv, DPIO_PHY1);
>  
>  		val = dev_priv->bxt_phy_grc = broxton_get_grc(dev_priv,
>  							      DPIO_PHY1);
> @@ -1878,6 +1883,10 @@ static void broxton_phy_init(struct drm_i915_private *dev_priv,
>  		val |= GRC_DIS | GRC_RDY_OVRD;
>  		I915_WRITE(BXT_PORT_REF_DW8(DPIO_PHY0), val);
>  	}
> +	/*
> +	 * During PHY1 init delay waiting for GRC calibration to finish, since
> +	 * it can happen in parallel with the subsequent PHY0 init.
> +	 */
>  
>  	val = I915_READ(BXT_PHY_CTL_FAMILY(phy));
>  	val |= COMMON_RESET_DIS;
> @@ -1889,6 +1898,12 @@ void broxton_ddi_phy_init(struct drm_i915_private *dev_priv)
>  	/* Enable PHY1 first since it provides Rcomp for PHY0 */
>  	broxton_phy_init(dev_priv, DPIO_PHY1);
>  	broxton_phy_init(dev_priv, DPIO_PHY0);
> +
> +	/*
> +	 * If BIOS enabled only PHY0 and not PHY1, we skipped waiting for the
> +	 * PHY1 GRC calibration to finish, so wait for it here.
> +	 */
> +	broxton_phy_wait_grc_done(dev_priv, DPIO_PHY1);

Hmm. Should we just do that always in the PHY1 init? A tad slower
perhaps but maybe less confusing?

Anyway series looks fine to me
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

>  }
>  
>  static void broxton_phy_uninit(struct drm_i915_private *dev_priv,
> -- 
> 2.5.0

-- 
Ville Syrjälä
Intel OTC