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

[Imre Deak]

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.

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..e68914a 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 PHY1 GRC\n");
+}
+
 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);
 }
 
 static void broxton_phy_uninit(struct drm_i915_private *dev_priv,
-- 
2.5.0