drm/i915/cnl: Introduce initial Cannonlake Workarounds.

Let's inherit workarounds from previous platforms that
according to wa_database and BSpec are still valid for
Cannonlake.

v2: Add missed workarounds.
v3: Rebase
v4: Remove bad chunk that was added to rc6 disable. (Ander)
    Also remove A0 W/a that are not needed anymore.
v5: Rebase on top of CFL.
v6: Remove empty gen9_init_perctx_bb and gen9_init_indirectctx_bb
    since they don't carry any gen10 related W/a. (by Oscar).
    Also Remove A0 exclusive workaround.
v7: Remove more A0 exclusive workarounds. As pointed out by Oscar
    many workarounds were changed to be A0 only so let's remove
    them.

Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Oscar Mateo <oscar.mateo@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170815231651.975-1-rodrigo.vivi@intel.com
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index ed66293..48db4b5 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -8263,6 +8263,23 @@ static void gen8_set_l3sqc_credits(struct drm_i915_private *dev_priv,
 	I915_WRITE(GEN7_MISCCPCTL, misccpctl);
 }
 
+static void cannonlake_init_clock_gating(struct drm_i915_private *dev_priv)
+{
+	/* WaEnableChickenDCPR:cnl */
+	I915_WRITE(GEN8_CHICKEN_DCPR_1,
+		   I915_READ(GEN8_CHICKEN_DCPR_1) | MASK_WAKEMEM);
+
+	/* WaFbcWakeMemOn:cnl */
+	I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
+		   DISP_FBC_MEMORY_WAKE);
+
+	/* WaSarbUnitClockGatingDisable:cnl (pre-prod) */
+	if (IS_CNL_REVID(dev_priv, CNL_REVID_A0, CNL_REVID_B0))
+		I915_WRITE(SLICE_UNIT_LEVEL_CLKGATE,
+			   I915_READ(SLICE_UNIT_LEVEL_CLKGATE) |
+			   SARBUNIT_CLKGATE_DIS);
+}
+
 static void kabylake_init_clock_gating(struct drm_i915_private *dev_priv)
 {
 	gen9_init_clock_gating(dev_priv);
@@ -8743,7 +8760,9 @@ static void nop_init_clock_gating(struct drm_i915_private *dev_priv)
  */
 void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv)
 {
-	if (IS_SKYLAKE(dev_priv))
+	if (IS_CANNONLAKE(dev_priv))
+		dev_priv->display.init_clock_gating = cannonlake_init_clock_gating;
+	else if (IS_SKYLAKE(dev_priv))
 		dev_priv->display.init_clock_gating = skylake_init_clock_gating;
 	else if (IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv))
 		dev_priv->display.init_clock_gating = kabylake_init_clock_gating;