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>

4 files changed, 75 insertions, 46 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 02fce7fbcd8a..0de75a23f8e7 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/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);
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1f77d8c6c6a2..455260067ff7 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/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);
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 147cd9666700..0521ecf26017 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/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);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f3c0525d5328..1190efa390bd 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/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);