drm/i915: Move load time init of clock gating hooks earlier

Split out the part initing the clock gating hooks and move it earlier.
Add a new NOP hook for platforms without the need to apply clockgating
or workaround settings, so that the hook can be called unconditionally.
Also add a WARN for future platforms that forget to add a hook.

The rest of the hooks in intel_init_pm() should be inited in the same
way, but atm some of the hooks are set only conditionally, so before
doing this we need to make the setup unconditional and use instead some
flags.

v2:
- add a NOP hook and WARN if no hook is set for the platform (Chris)
- use the term hook instead of callback for these functions (Jani)
v3:
- remove the GEN4() check it's already covered by earlier platform
  checks (Chris)

CC: Jani Nikula <jani.nikula@intel.com>
CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1458128348-15730-6-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/i915_dma.c

@@ -1029,6 +1029,7 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	intel_power_domains_init(dev_priv);
 	intel_irq_init(dev_priv);
 	intel_init_display_hooks(dev_priv);
+	intel_init_clock_gating_hooks(dev_priv);
 	intel_init_audio_hooks(dev_priv);
 
 	intel_runtime_pm_get(dev_priv);

drivers/gpu/drm/i915/intel_drv.h

@@ -1569,6 +1569,7 @@ void intel_suspend_hw(struct drm_device *dev);
 int ilk_wm_max_level(const struct drm_device *dev);
 void intel_update_watermarks(struct drm_crtc *crtc);
 void intel_init_pm(struct drm_device *dev);
+void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv);
 void intel_pm_setup(struct drm_device *dev);
 void intel_gpu_ips_init(struct drm_i915_private *dev_priv);
 void intel_gpu_ips_teardown(void);

drivers/gpu/drm/i915/intel_pm.c

@@ -7097,8 +7097,7 @@ void intel_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (dev_priv->display.init_clock_gating)
-		dev_priv->display.init_clock_gating(dev);
+	dev_priv->display.init_clock_gating(dev);
 }
 
 void intel_suspend_hw(struct drm_device *dev)
@@ -7107,6 +7106,60 @@ void intel_suspend_hw(struct drm_device *dev)
 		lpt_suspend_hw(dev);
 }
 
+static void nop_init_clock_gating(struct drm_device *dev)
+{
+	DRM_DEBUG_KMS("No clock gating settings or workarounds applied.\n");
+}
+
+/**
+ * intel_init_clock_gating_hooks - setup the clock gating hooks
+ * @dev_priv: device private
+ *
+ * Setup the hooks that configure which clocks of a given platform can be
+ * gated and also apply various GT and display specific workarounds for these
+ * platforms. Note that some GT specific workarounds are applied separately
+ * when GPU contexts or batchbuffers start their execution.
+ */
+void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv)
+{
+	if (IS_SKYLAKE(dev_priv))
+		dev_priv->display.init_clock_gating = nop_init_clock_gating;
+	else if (IS_KABYLAKE(dev_priv))
+		dev_priv->display.init_clock_gating = nop_init_clock_gating;
+	else if (IS_BROXTON(dev_priv))
+		dev_priv->display.init_clock_gating = bxt_init_clock_gating;
+	else if (IS_BROADWELL(dev_priv))
+		dev_priv->display.init_clock_gating = broadwell_init_clock_gating;
+	else if (IS_CHERRYVIEW(dev_priv))
+		dev_priv->display.init_clock_gating = cherryview_init_clock_gating;
+	else if (IS_HASWELL(dev_priv))
+		dev_priv->display.init_clock_gating = haswell_init_clock_gating;
+	else if (IS_IVYBRIDGE(dev_priv))
+		dev_priv->display.init_clock_gating = ivybridge_init_clock_gating;
+	else if (IS_VALLEYVIEW(dev_priv))
+		dev_priv->display.init_clock_gating = valleyview_init_clock_gating;
+	else if (IS_GEN6(dev_priv))
+		dev_priv->display.init_clock_gating = gen6_init_clock_gating;
+	else if (IS_GEN5(dev_priv))
+		dev_priv->display.init_clock_gating = ironlake_init_clock_gating;
+	else if (IS_G4X(dev_priv))
+		dev_priv->display.init_clock_gating = g4x_init_clock_gating;
+	else if (IS_CRESTLINE(dev_priv))
+		dev_priv->display.init_clock_gating = crestline_init_clock_gating;
+	else if (IS_BROADWATER(dev_priv))
+		dev_priv->display.init_clock_gating = broadwater_init_clock_gating;
+	else if (IS_GEN3(dev_priv))
+		dev_priv->display.init_clock_gating = gen3_init_clock_gating;
+	else if (IS_I85X(dev_priv) || IS_I865G(dev_priv))
+		dev_priv->display.init_clock_gating = i85x_init_clock_gating;
+	else if (IS_GEN2(dev_priv))
+		dev_priv->display.init_clock_gating = i830_init_clock_gating;
+	else {
+		MISSING_CASE(INTEL_DEVID(dev_priv));
+		dev_priv->display.init_clock_gating = nop_init_clock_gating;
+	}
+}
+
 /* Set up chip specific power management-related functions */
 void intel_init_pm(struct drm_device *dev)
 {
@@ -7123,10 +7176,6 @@ void intel_init_pm(struct drm_device *dev)
 	/* For FIFO watermark updates */
 	if (INTEL_INFO(dev)->gen >= 9) {
 		skl_setup_wm_latency(dev);
-
-		if (IS_BROXTON(dev))
-			dev_priv->display.init_clock_gating =
-				bxt_init_clock_gating;
 		dev_priv->display.update_wm = skl_update_wm;
 	} else if (HAS_PCH_SPLIT(dev)) {
 		ilk_setup_wm_latency(dev);
@@ -7146,29 +7195,12 @@ void intel_init_pm(struct drm_device *dev)
 			DRM_DEBUG_KMS("Failed to read display plane latency. "
 				      "Disable CxSR\n");
 		}
-
-		if (IS_GEN5(dev))
-			dev_priv->display.init_clock_gating = ironlake_init_clock_gating;
-		else if (IS_GEN6(dev))
-			dev_priv->display.init_clock_gating = gen6_init_clock_gating;
-		else if (IS_IVYBRIDGE(dev))
-			dev_priv->display.init_clock_gating = ivybridge_init_clock_gating;
-		else if (IS_HASWELL(dev))
-			dev_priv->display.init_clock_gating = haswell_init_clock_gating;
-		else if (INTEL_INFO(dev)->gen == 8)
-			dev_priv->display.init_clock_gating = broadwell_init_clock_gating;
 	} else if (IS_CHERRYVIEW(dev)) {
 		vlv_setup_wm_latency(dev);
-
 		dev_priv->display.update_wm = vlv_update_wm;
-		dev_priv->display.init_clock_gating =
-			cherryview_init_clock_gating;
 	} else if (IS_VALLEYVIEW(dev)) {
 		vlv_setup_wm_latency(dev);
-
 		dev_priv->display.update_wm = vlv_update_wm;
-		dev_priv->display.init_clock_gating =
-			valleyview_init_clock_gating;
 	} else if (IS_PINEVIEW(dev)) {
 		if (!intel_get_cxsr_latency(IS_PINEVIEW_G(dev),
 					    dev_priv->is_ddr3,
@@ -7184,20 +7216,13 @@ void intel_init_pm(struct drm_device *dev)
 			dev_priv->display.update_wm = NULL;
 		} else
 			dev_priv->display.update_wm = pineview_update_wm;
-		dev_priv->display.init_clock_gating = gen3_init_clock_gating;
 	} else if (IS_G4X(dev)) {
 		dev_priv->display.update_wm = g4x_update_wm;
-		dev_priv->display.init_clock_gating = g4x_init_clock_gating;
 	} else if (IS_GEN4(dev)) {
 		dev_priv->display.update_wm = i965_update_wm;
-		if (IS_CRESTLINE(dev))
-			dev_priv->display.init_clock_gating = crestline_init_clock_gating;
-		else if (IS_BROADWATER(dev))
-			dev_priv->display.init_clock_gating = broadwater_init_clock_gating;
 	} else if (IS_GEN3(dev)) {
 		dev_priv->display.update_wm = i9xx_update_wm;
 		dev_priv->display.get_fifo_size = i9xx_get_fifo_size;
-		dev_priv->display.init_clock_gating = gen3_init_clock_gating;
 	} else if (IS_GEN2(dev)) {
 		if (INTEL_INFO(dev)->num_pipes == 1) {
 			dev_priv->display.update_wm = i845_update_wm;
@@ -7206,11 +7231,6 @@ void intel_init_pm(struct drm_device *dev)
 			dev_priv->display.update_wm = i9xx_update_wm;
 			dev_priv->display.get_fifo_size = i830_get_fifo_size;
 		}
-
-		if (IS_I85X(dev) || IS_I865G(dev))
-			dev_priv->display.init_clock_gating = i85x_init_clock_gating;
-		else
-			dev_priv->display.init_clock_gating = i830_init_clock_gating;
 	} else {
 		DRM_ERROR("unexpected fall-through in intel_init_pm\n");
 	}