drm/i915/hsw, bdw: Wait for the power well disabled state

Similarly to GEN9+ waiting for the power well disabled state is a safer
option and also provides diagnostic info if the disabling didn't succeed
or the power well was forced on by an external requester. While at it
also use the existing GEN9+ helper to wait for the enabled state.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1499352040-8819-15-git-send-email-imre.deak@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -346,8 +346,8 @@ static void skl_power_well_pre_disable(struct drm_i915_private *dev_priv,
 						1 << PIPE_C | 1 << PIPE_B);
 }
 
-static void gen9_wait_for_power_well_enable(struct drm_i915_private *dev_priv,
-					    struct i915_power_well *power_well)
+static void hsw_wait_for_power_well_enable(struct drm_i915_private *dev_priv,
+					   struct i915_power_well *power_well)
 {
 	enum i915_power_well_id id = power_well->id;
 
@@ -359,8 +359,8 @@ static void gen9_wait_for_power_well_enable(struct drm_i915_private *dev_priv,
 					1));
 }
 
-static u32 gen9_power_well_requesters(struct drm_i915_private *dev_priv,
-				      enum i915_power_well_id id)
+static u32 hsw_power_well_requesters(struct drm_i915_private *dev_priv,
+				     enum i915_power_well_id id)
 {
 	u32 req_mask = HSW_PWR_WELL_CTL_REQ(id);
 	u32 ret;
@@ -373,8 +373,8 @@ static u32 gen9_power_well_requesters(struct drm_i915_private *dev_priv,
 	return ret;
 }
 
-static void gen9_wait_for_power_well_disable(struct drm_i915_private *dev_priv,
-					     struct i915_power_well *power_well)
+static void hsw_wait_for_power_well_disable(struct drm_i915_private *dev_priv,
+					    struct i915_power_well *power_well)
 {
 	enum i915_power_well_id id = power_well->id;
 	bool disabled;
@@ -391,7 +391,7 @@ static void gen9_wait_for_power_well_disable(struct drm_i915_private *dev_priv,
 	 */
 	wait_for((disabled = !(I915_READ(HSW_PWR_WELL_DRIVER) &
 			       HSW_PWR_WELL_CTL_STATE(id))) ||
-		 (reqs = gen9_power_well_requesters(dev_priv, id)), 1);
+		 (reqs = hsw_power_well_requesters(dev_priv, id)), 1);
 	if (disabled)
 		return;
 
@@ -408,13 +408,7 @@ static void hsw_power_well_enable(struct drm_i915_private *dev_priv,
 
 	val = I915_READ(HSW_PWR_WELL_DRIVER);
 	I915_WRITE(HSW_PWR_WELL_DRIVER, val | HSW_PWR_WELL_CTL_REQ(id));
-
-	if (intel_wait_for_register(dev_priv,
-				    HSW_PWR_WELL_DRIVER,
-				    HSW_PWR_WELL_CTL_STATE(id),
-				    HSW_PWR_WELL_CTL_STATE(id),
-				    20))
-		DRM_ERROR("Timeout enabling power well\n");
+	hsw_wait_for_power_well_enable(dev_priv, power_well);
 
 	hsw_power_well_post_enable(dev_priv, power_well->hsw.irq_pipe_mask,
 				   power_well->hsw.has_vga);
@@ -430,7 +424,7 @@ static void hsw_power_well_disable(struct drm_i915_private *dev_priv,
 
 	val = I915_READ(HSW_PWR_WELL_DRIVER);
 	I915_WRITE(HSW_PWR_WELL_DRIVER, val & ~HSW_PWR_WELL_CTL_REQ(id));
-	POSTING_READ(HSW_PWR_WELL_DRIVER);
+	hsw_wait_for_power_well_disable(dev_priv, power_well);
 }
 
 #define SKL_DISPLAY_POWERWELL_2_POWER_DOMAINS (		\
@@ -856,13 +850,13 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
 		DRM_DEBUG_KMS("Enabling %s\n", power_well->name);
 		check_fuse_status = true;
 
-		gen9_wait_for_power_well_enable(dev_priv, power_well);
+		hsw_wait_for_power_well_enable(dev_priv, power_well);
 	} else {
 		I915_WRITE(HSW_PWR_WELL_DRIVER,	tmp & ~req_mask);
 		POSTING_READ(HSW_PWR_WELL_DRIVER);
 		DRM_DEBUG_KMS("Disabling %s\n", power_well->name);
 
-		gen9_wait_for_power_well_disable(dev_priv, power_well);
+		hsw_wait_for_power_well_disable(dev_priv, power_well);
 	}
 
 	if (check_fuse_status) {