drm/i915: Separate RPS and RC6 handling for BDW

This patch separates RC6 and RPS enabling for BDW.
RC6/RPS Disabling are handled through gen6 functions.
PM Programming guide recommends a sequence within forcewakes to
configure RC6, RPS and ring frequencies in sequence. With this
patch the order is still maintained.

v2: Update sequence numbers in RC6 programming and comment about
intent of reset_rps during gen8_enable_rps. (Radoslaw)

v3: Rebase.

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1507360055-19948-4-git-send-email-sagar.a.kamble@intel.com
Acked-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171010213010.7415-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_pm.c

@@ -6621,7 +6621,7 @@ static void gen9_enable_rc6(struct drm_i915_private *dev_priv)
 	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
 }
 
-static void gen8_enable_rps(struct drm_i915_private *dev_priv)
+static void gen8_enable_rc6(struct drm_i915_private *dev_priv)
 {
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
@@ -6630,7 +6630,7 @@ static void gen8_enable_rps(struct drm_i915_private *dev_priv)
 	/* 1a: Software RC state - RC0 */
 	I915_WRITE(GEN6_RC_STATE, 0);
 
-	/* 1c & 1d: Get forcewake during program sequence. Although the driver
+	/* 1b: Get forcewake during program sequence. Although the driver
 	 * hasn't enabled a state yet where we need forcewake, BIOS may have.*/
 	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
 
@@ -6655,7 +6655,14 @@ static void gen8_enable_rps(struct drm_i915_private *dev_priv)
 			GEN7_RC_CTL_TO_MODE |
 			rc6_mask);
 
-	/* 4 Program defaults and thresholds for RPS*/
+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+}
+
+static void gen8_enable_rps(struct drm_i915_private *dev_priv)
+{
+	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+
+	/* 1 Program defaults and thresholds for RPS*/
 	I915_WRITE(GEN6_RPNSWREQ,
 		   HSW_FREQUENCY(dev_priv->rps.rp1_freq));
 	I915_WRITE(GEN6_RC_VIDEO_FREQ,
@@ -6675,7 +6682,7 @@ static void gen8_enable_rps(struct drm_i915_private *dev_priv)
 
 	I915_WRITE(GEN6_RP_IDLE_HYSTERSIS, 10);
 
-	/* 5: Enable RPS */
+	/* 2: Enable RPS */
 	I915_WRITE(GEN6_RP_CONTROL,
 		   GEN6_RP_MEDIA_TURBO |
 		   GEN6_RP_MEDIA_HW_NORMAL_MODE |
@@ -6684,8 +6691,6 @@ static void gen8_enable_rps(struct drm_i915_private *dev_priv)
 		   GEN6_RP_UP_BUSY_AVG |
 		   GEN6_RP_DOWN_IDLE_AVG);
 
-	/* 6: Ring frequency + overclocking (our driver does this later */
-
 	reset_rps(dev_priv, gen6_set_rps);
 
 	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
@@ -7976,6 +7981,7 @@ void intel_enable_gt_powersave(struct drm_i915_private *dev_priv)
 		if (IS_GEN9_BC(dev_priv) || IS_CANNONLAKE(dev_priv))
 			gen6_update_ring_freq(dev_priv);
 	} else if (IS_BROADWELL(dev_priv)) {
+		gen8_enable_rc6(dev_priv);
 		gen8_enable_rps(dev_priv);
 		gen6_update_ring_freq(dev_priv);
 	} else if (INTEL_GEN(dev_priv) >= 6) {