drm/i915: Replace bxt_verify_cdclk_state() with a more generic cdclk check

Rather than having a BXT specific function to make sure the DE PLL is
enabled after disabling DC6, let's just make sure the current cdclk
is the same as what we last programmed.

Having another check in bxt_display_core_init() almost immediately after
the cdclk init seems redundant, so let's just kill that one.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463172100-24715-21-git-send-email-ville.syrjala@linux.intel.comReviewed-by: Imre Deak <imre.deak@intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -5410,21 +5410,6 @@ static void broxton_set_cdclk(struct drm_i915_private *dev_priv, int cdclk)
 	intel_update_cdclk(dev_priv->dev);
 }
 
-static bool broxton_cdclk_is_enabled(struct drm_i915_private *dev_priv)
-{
-	if (!(I915_READ(BXT_DE_PLL_ENABLE) & BXT_DE_PLL_PLL_ENABLE))
-		return false;
-
-	/* TODO: Check for a valid CDCLK rate */
-
-	return true;
-}
-
-bool broxton_cdclk_verify_state(struct drm_i915_private *dev_priv)
-{
-	return broxton_cdclk_is_enabled(dev_priv);
-}
-
 void broxton_init_cdclk(struct drm_i915_private *dev_priv)
 {
 	intel_update_cdclk(dev_priv->dev);

drivers/gpu/drm/i915/intel_drv.h

@@ -1270,7 +1270,6 @@ void hsw_enable_pc8(struct drm_i915_private *dev_priv);
 void hsw_disable_pc8(struct drm_i915_private *dev_priv);
 void broxton_init_cdclk(struct drm_i915_private *dev_priv);
 void broxton_uninit_cdclk(struct drm_i915_private *dev_priv);
-bool broxton_cdclk_verify_state(struct drm_i915_private *dev_priv);
 void broxton_ddi_phy_init(struct drm_i915_private *dev_priv);
 void broxton_ddi_phy_uninit(struct drm_i915_private *dev_priv);
 void broxton_ddi_phy_verify_state(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -811,10 +811,11 @@ static void gen9_dc_off_power_well_enable(struct drm_i915_private *dev_priv,
 {
 	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
 
-	if (IS_BROXTON(dev_priv)) {
-		broxton_cdclk_verify_state(dev_priv);
+	WARN_ON(dev_priv->cdclk_freq !=
+		dev_priv->display.get_display_clock_speed(dev_priv->dev));
+
+	if (IS_BROXTON(dev_priv))
 		broxton_ddi_phy_verify_state(dev_priv);
-	}
 }
 
 static void gen9_dc_off_power_well_disable(struct drm_i915_private *dev_priv,
@@ -2288,7 +2289,6 @@ void bxt_display_core_init(struct drm_i915_private *dev_priv,
 
 	broxton_ddi_phy_init(dev_priv);
 
-	broxton_cdclk_verify_state(dev_priv);
 	broxton_ddi_phy_verify_state(dev_priv);
 
 	if (resume && dev_priv->csr.dmc_payload)