drm/i915: cleanup rc6 code

Cleanup several aspects of the rc6 code:
  - misnamed intel_disable_clock_gating function (was only about rc6)
  - remove commented call to intel_disable_clock_gating
  - rc6 enabling code belongs in its own function (allows us to move the
    actual clock gating enable call back into restore_state)
  - allocate power & render contexts up front, only free on unload
    (avoids ugly lazy init at rc6 enable time)
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[ickle: checkpatch cleanup]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_drv.c

@@ -355,10 +355,10 @@ static int i915_drm_thaw(struct drm_device *dev)
 
 		/* Resume the modeset for every activated CRTC */
 		drm_helper_resume_force_mode(dev);
-	}
 
-	/* Clock gating state */
-	intel_enable_clock_gating(dev);
+		if (dev_priv->renderctx && dev_priv->pwrctx)
+			ironlake_enable_rc6(dev);
+	}
 
 	intel_opregion_init(dev);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -1260,6 +1260,7 @@ extern void intel_disable_fbc(struct drm_device *dev);
 extern void intel_enable_fbc(struct drm_crtc *crtc, unsigned long interval);
 extern bool intel_fbc_enabled(struct drm_device *dev);
 extern bool ironlake_set_drps(struct drm_device *dev, u8 val);
+extern void ironlake_enable_rc6(struct drm_device *dev);
 extern void gen6_set_rps(struct drm_device *dev, u8 val);
 extern void intel_detect_pch (struct drm_device *dev);
 extern int intel_trans_dp_port_sel (struct drm_crtc *crtc);

drivers/gpu/drm/i915/i915_suspend.c

@@ -822,10 +822,6 @@ int i915_save_state(struct drm_device *dev)
 	if (IS_GEN6(dev))
 		gen6_disable_rps(dev);
 
-	/* XXX disabling the clock gating breaks suspend on gm45
-	intel_disable_clock_gating(dev);
-	 */
-
 	/* Cache mode state */
 	dev_priv->saveCACHE_MODE_0 = I915_READ(CACHE_MODE_0);
 
@@ -868,6 +864,9 @@ int i915_restore_state(struct drm_device *dev)
 		I915_WRITE (IMR,  dev_priv->saveIMR);
 	}
 
+	/* Clock gating state */
+	intel_enable_clock_gating(dev);
+
 	if (IS_IRONLAKE_M(dev)) {
 		ironlake_enable_drps(dev);
 		intel_init_emon(dev);

drivers/gpu/drm/i915/intel_display.c

@@ -6415,44 +6415,6 @@ void intel_enable_clock_gating(struct drm_device *dev)
 	} else if (IS_I830(dev)) {
 		I915_WRITE(DSPCLK_GATE_D, OVRUNIT_CLOCK_GATE_DISABLE);
 	}
-
-	/*
-	 * GPU can automatically power down the render unit if given a page
-	 * to save state.
-	 */
-	if (IS_IRONLAKE_M(dev)) {
-		if (dev_priv->renderctx == NULL)
-			dev_priv->renderctx = intel_alloc_context_page(dev);
-		if (dev_priv->renderctx) {
-			struct drm_i915_gem_object *obj = dev_priv->renderctx;
-			if (BEGIN_LP_RING(6) != 0) {
-				i915_gem_object_unpin(obj);
-				drm_gem_object_unreference(&obj->base);
-				dev_priv->renderctx = NULL;
-				return;
-			}
-			OUT_RING(MI_SUSPEND_FLUSH | MI_SUSPEND_FLUSH_EN);
-			OUT_RING(MI_SET_CONTEXT);
-			OUT_RING(obj->gtt_offset |
-				 MI_MM_SPACE_GTT |
-				 MI_SAVE_EXT_STATE_EN |
-				 MI_RESTORE_EXT_STATE_EN |
-				 MI_RESTORE_INHIBIT);
-			OUT_RING(MI_SUSPEND_FLUSH);
-			OUT_RING(MI_NOOP);
-			OUT_RING(MI_FLUSH);
-			ADVANCE_LP_RING();
-		} else
-			DRM_DEBUG_KMS("Failed to allocate render context."
-				       "Disable RC6\n");
-
-		if (dev_priv->pwrctx == NULL)
-			dev_priv->pwrctx = intel_alloc_context_page(dev);
-		if (dev_priv->pwrctx) {
-			struct drm_i915_gem_object *obj = dev_priv->pwrctx;
-			I915_WRITE(PWRCTXA, obj->gtt_offset | PWRCTX_EN);
-		}
-	}
 }
 
 void intel_disable_clock_gating(struct drm_device *dev)
@@ -6482,6 +6444,57 @@ void intel_disable_clock_gating(struct drm_device *dev)
 	}
 }
 
+static void ironlake_disable_rc6(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	/* Wake the GPU, prevent RC6, then restore RSTDBYCTL */
+	I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) | RCX_SW_EXIT);
+	wait_for(((I915_READ(RSTDBYCTL) & RSX_STATUS_MASK) == RSX_STATUS_ON),
+		 10);
+	POSTING_READ(CCID);
+	I915_WRITE(PWRCTXA, 0);
+	POSTING_READ(PWRCTXA);
+	I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) & ~RCX_SW_EXIT);
+	POSTING_READ(RSTDBYCTL);
+	i915_gem_object_unpin(dev_priv->renderctx);
+	drm_gem_object_unreference(&dev_priv->renderctx->base);
+	dev_priv->renderctx = NULL;
+	i915_gem_object_unpin(dev_priv->pwrctx);
+	drm_gem_object_unreference(&dev_priv->pwrctx->base);
+	dev_priv->pwrctx = NULL;
+}
+
+void ironlake_enable_rc6(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret;
+
+	/*
+	 * GPU can automatically power down the render unit if given a page
+	 * to save state.
+	 */
+	ret = BEGIN_LP_RING(6);
+	if (ret) {
+		ironlake_disable_rc6(dev);
+		return;
+	}
+	OUT_RING(MI_SUSPEND_FLUSH | MI_SUSPEND_FLUSH_EN);
+	OUT_RING(MI_SET_CONTEXT);
+	OUT_RING(dev_priv->renderctx->gtt_offset |
+		 MI_MM_SPACE_GTT |
+		 MI_SAVE_EXT_STATE_EN |
+		 MI_RESTORE_EXT_STATE_EN |
+		 MI_RESTORE_INHIBIT);
+	OUT_RING(MI_SUSPEND_FLUSH);
+	OUT_RING(MI_NOOP);
+	OUT_RING(MI_FLUSH);
+	ADVANCE_LP_RING();
+
+	I915_WRITE(PWRCTXA, dev_priv->pwrctx->gtt_offset | PWRCTX_EN);
+	I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) & ~RCX_SW_EXIT);
+}
+
 /* Set up chip specific display functions */
 static void intel_init_display(struct drm_device *dev)
 {
@@ -6724,6 +6737,21 @@ void intel_modeset_init(struct drm_device *dev)
 	if (IS_GEN6(dev))
 		gen6_enable_rps(dev_priv);
 
+	if (IS_IRONLAKE_M(dev)) {
+		dev_priv->renderctx = intel_alloc_context_page(dev);
+		if (!dev_priv->renderctx)
+			goto skip_rc6;
+		dev_priv->pwrctx = intel_alloc_context_page(dev);
+		if (!dev_priv->pwrctx) {
+			i915_gem_object_unpin(dev_priv->renderctx);
+			drm_gem_object_unreference(&dev_priv->renderctx->base);
+			dev_priv->renderctx = NULL;
+			goto skip_rc6;
+		}
+		ironlake_enable_rc6(dev);
+	}
+
+skip_rc6:
 	INIT_WORK(&dev_priv->idle_work, intel_idle_update);
 	setup_timer(&dev_priv->idle_timer, intel_gpu_idle_timer,
 		    (unsigned long)dev);
@@ -6760,7 +6788,8 @@ void intel_modeset_cleanup(struct drm_device *dev)
 	if (IS_GEN6(dev))
 		gen6_disable_rps(dev);
 
-	intel_disable_clock_gating(dev);
+	if (IS_IRONLAKE_M(dev))
+		ironlake_disable_rc6(dev);
 
 	mutex_unlock(&dev->struct_mutex);