drm/i915: Disable/Enable PM Intrrupts based on the current freq.

When current delay is already at max delay, Let's disable the PM UP
THRESHOLD INTRRUPTS, so that we will not get further interrupts until
current delay is less than max delay, Also request for the PM DOWN
THRESHOLD INTRRUPTS to indicate the decrease in clock freq. and
viceversa for PM DOWN THRESHOLD INTRRUPTS.

v2: Use bool variables (Daniel)

v3: Fix Interrupt masking bit (Deepak)

v4: Use existing symbolic constants in i915_reg.h (Daniel)

v5: Add pm interrupt mask after new_delay calculation (Ville)

Signed-off-by: Deepak S <deepak.s@intel.com>
[danvet: Pass new_delay by value as suggested by Ville. Also appease
checkpatch.]
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -938,6 +938,9 @@ struct intel_gen6_power_mgmt {
 	u8 rp0_delay;
 	u8 hw_max;
 
+	bool rp_up_masked;
+	bool rp_down_masked;
+
 	int last_adj;
 	enum { LOW_POWER, BETWEEN, HIGH_POWER } power;
 

drivers/gpu/drm/i915/i915_irq.c

@@ -986,6 +986,43 @@ static void notify_ring(struct drm_device *dev,
 	i915_queue_hangcheck(dev);
 }
 
+static void gen6_set_pm_mask(struct drm_i915_private *dev_priv,
+			     u32 pm_iir, int new_delay)
+{
+	if (pm_iir & GEN6_PM_RP_UP_THRESHOLD) {
+		if (new_delay >= dev_priv->rps.max_delay) {
+			/* Mask UP THRESHOLD Interrupts */
+			I915_WRITE(GEN6_PMINTRMSK,
+				   I915_READ(GEN6_PMINTRMSK) |
+				   GEN6_PM_RP_UP_THRESHOLD);
+			dev_priv->rps.rp_up_masked = true;
+		}
+		if (dev_priv->rps.rp_down_masked) {
+			/* UnMask DOWN THRESHOLD Interrupts */
+			I915_WRITE(GEN6_PMINTRMSK,
+				   I915_READ(GEN6_PMINTRMSK) &
+				   ~GEN6_PM_RP_DOWN_THRESHOLD);
+			dev_priv->rps.rp_down_masked = false;
+		}
+	} else if (pm_iir & GEN6_PM_RP_DOWN_THRESHOLD) {
+		if (new_delay <= dev_priv->rps.min_delay) {
+			/* Mask DOWN THRESHOLD Interrupts */
+			I915_WRITE(GEN6_PMINTRMSK,
+				   I915_READ(GEN6_PMINTRMSK) |
+				   GEN6_PM_RP_DOWN_THRESHOLD);
+			dev_priv->rps.rp_down_masked = true;
+		}
+
+		if (dev_priv->rps.rp_up_masked) {
+			/* UnMask UP THRESHOLD Interrupts */
+			I915_WRITE(GEN6_PMINTRMSK,
+				   I915_READ(GEN6_PMINTRMSK) &
+				   ~GEN6_PM_RP_UP_THRESHOLD);
+			dev_priv->rps.rp_up_masked = false;
+		}
+	}
+}
+
 static void gen6_pm_rps_work(struct work_struct *work)
 {
 	drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
@@ -1043,6 +1080,8 @@ static void gen6_pm_rps_work(struct work_struct *work)
 	 */
 	new_delay = clamp_t(int, new_delay,
 			    dev_priv->rps.min_delay, dev_priv->rps.max_delay);
+
+	gen6_set_pm_mask(dev_priv, pm_iir, new_delay);
 	dev_priv->rps.last_adj = new_delay - dev_priv->rps.cur_delay;
 
 	if (IS_VALLEYVIEW(dev_priv->dev))

drivers/gpu/drm/i915/intel_pm.c

@@ -3618,6 +3618,9 @@ static void valleyview_enable_rps(struct drm_device *dev)
 
 	valleyview_set_rps(dev_priv->dev, dev_priv->rps.rpe_delay);
 
+	dev_priv->rps.rp_up_masked = false;
+	dev_priv->rps.rp_down_masked = false;
+
 	gen6_enable_rps_interrupts(dev);
 
 	gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);