drm/i915: Use coarse grained residency counter with byt

Set byt rc residency counters high level as chv does by
default. We lose some accuracy on byt but we can do the calculation
without extra hw read on both platforms, as now they behave
identically in this respect.

v2: use ktime
v3: keep comparison u32 (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1489592584-10422-1-git-send-email-mika.kuoppala@intel.com

drivers/gpu/drm/i915/i915_irq.c

@@ -1102,11 +1102,6 @@ static u32 vlv_wa_c0_ei(struct drm_i915_private *dev_priv, u32 pm_iir)
 	if (prev->ktime) {
 		u64 time, c0;
 		u32 render, media;
-		unsigned int mul;
-
-		mul = 1000 * 100; /* scale to threshold% */
-		if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
-			mul <<= 8;
 
 		time = ktime_us_delta(now.ktime, prev->ktime);
 		time *= dev_priv->czclk_freq;
@@ -1119,7 +1114,7 @@ static u32 vlv_wa_c0_ei(struct drm_i915_private *dev_priv, u32 pm_iir)
 		render = now.render_c0 - prev->render_c0;
 		media = now.media_c0 - prev->media_c0;
 		c0 = max(render, media);
-		c0 *= mul;
+		c0 *= 1000 * 100 << 8; /* to usecs and scale to threshold% */
 
 		if (c0 > time * dev_priv->rps.up_threshold)
 			events = GEN6_PM_RP_UP_THRESHOLD;

drivers/gpu/drm/i915/intel_pm.c

@@ -6392,7 +6392,8 @@ static void valleyview_enable_rps(struct drm_i915_private *dev_priv)
 
 	/* allows RC6 residency counter to work */
 	I915_WRITE(VLV_COUNTER_CONTROL,
-		   _MASKED_BIT_ENABLE(VLV_MEDIA_RC0_COUNT_EN |
+		   _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH |
+				      VLV_MEDIA_RC0_COUNT_EN |
 				      VLV_RENDER_RC0_COUNT_EN |
 				      VLV_MEDIA_RC6_COUNT_EN |
 				      VLV_RENDER_RC6_COUNT_EN));
@@ -8361,7 +8362,7 @@ static u64 vlv_residency_raw(struct drm_i915_private *dev_priv,
 	spin_lock_irq(&dev_priv->uncore.lock);
 	saved_ctl = I915_READ_FW(VLV_COUNTER_CONTROL);
 
-	if (!(saved_ctl & VLV_COUNT_RANGE_HIGH))
+	if (WARN_ON(!(saved_ctl & VLV_COUNT_RANGE_HIGH)))
 		I915_WRITE_FW(VLV_COUNTER_CONTROL,
 			      _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH));
 
@@ -8382,10 +8383,6 @@ static u64 vlv_residency_raw(struct drm_i915_private *dev_priv,
 		upper = I915_READ_FW(reg);
 	} while (upper != tmp);
 
-	if (!(saved_ctl & VLV_COUNT_RANGE_HIGH))
-		I915_WRITE_FW(VLV_COUNTER_CONTROL,
-			      _MASKED_BIT_DISABLE(VLV_COUNT_RANGE_HIGH));
-
 	spin_unlock_irq(&dev_priv->uncore.lock);
 
 	return lower | (u64)upper << 8;