drm/i915: Clean up the irq enable/disable for ilk rps

Let's unmask the PCU event irq _after_ we've set up the
hardware and software to deal with the fallout. We can
also drop the PCU event bit from DEIER except when we
need it for rps.

And on the disable side we replace the hand rolled (and
unlocked) DEIER/IIR/IMR frobbing with ilk_disable_display_irq().
Ocd does require me to reorder it to be symmetric with
the enable path however.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201021131443.25616-5-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/gt/intel_rps.c

@@ -509,6 +509,7 @@ static unsigned int init_emon(struct intel_uncore *uncore)
 
 static bool gen5_rps_enable(struct intel_rps *rps)
 {
+	struct drm_i915_private *i915 = rps_to_i915(rps);
 	struct intel_uncore *uncore = rps_to_uncore(rps);
 	u8 fstart, vstart;
 	u32 rgvmodectl;
@@ -566,6 +567,10 @@ static bool gen5_rps_enable(struct intel_rps *rps)
 	rps->ips.last_count2 = intel_uncore_read(uncore, GFXEC);
 	rps->ips.last_time2 = ktime_get_raw_ns();
 
+	spin_lock(&i915->irq_lock);
+	ilk_enable_display_irq(i915, DE_PCU_EVENT);
+	spin_unlock(&i915->irq_lock);
+
 	spin_unlock_irq(&mchdev_lock);
 
 	rps->ips.corr = init_emon(uncore);
@@ -575,23 +580,23 @@ static bool gen5_rps_enable(struct intel_rps *rps)
 
 static void gen5_rps_disable(struct intel_rps *rps)
 {
+	struct drm_i915_private *i915 = rps_to_i915(rps);
 	struct intel_uncore *uncore = rps_to_uncore(rps);
 	u16 rgvswctl;
 
 	spin_lock_irq(&mchdev_lock);
 
+	spin_lock(&i915->irq_lock);
+	ilk_disable_display_irq(i915, DE_PCU_EVENT);
+	spin_unlock(&i915->irq_lock);
+
 	rgvswctl = intel_uncore_read16(uncore, MEMSWCTL);
 
 	/* Ack interrupts, disable EFC interrupt */
 	intel_uncore_write(uncore, MEMINTREN,
 			   intel_uncore_read(uncore, MEMINTREN) &
 			   ~MEMINT_EVAL_CHG_EN);
 	intel_uncore_write(uncore, MEMINTRSTS, MEMINT_EVAL_CHG);
-	intel_uncore_write(uncore, DEIER,
-			   intel_uncore_read(uncore, DEIER) & ~DE_PCU_EVENT);
-	intel_uncore_write(uncore, DEIIR, DE_PCU_EVENT);
-	intel_uncore_write(uncore, DEIMR,
-			   intel_uncore_read(uncore, DEIMR) | DE_PCU_EVENT);
 
 	/* Go back to the starting frequency */
 	gen5_rps_set(rps, rps->idle_freq);

drivers/gpu/drm/i915/i915_irq.c

@@ -3460,7 +3460,7 @@ static void ilk_irq_postinstall(struct drm_i915_private *dev_priv)
 		display_mask = (DE_MASTER_IRQ_CONTROL | DE_GSE | DE_PCH_EVENT |
 				DE_AUX_CHANNEL_A | DE_PIPEB_CRC_DONE |
 				DE_PIPEA_CRC_DONE | DE_POISON);
-		extra_mask = (DE_PIPEA_VBLANK | DE_PIPEB_VBLANK | DE_PCU_EVENT |
+		extra_mask = (DE_PIPEA_VBLANK | DE_PIPEB_VBLANK |
 			      DE_PIPEB_FIFO_UNDERRUN | DE_PIPEA_FIFO_UNDERRUN |
 			      DE_DP_A_HOTPLUG);
 	}
@@ -3470,6 +3470,9 @@ static void ilk_irq_postinstall(struct drm_i915_private *dev_priv)
 		display_mask |= DE_EDP_PSR_INT_HSW;
 	}
 
+	if (IS_IRONLAKE_M(dev_priv))
+		extra_mask |= DE_PCU_EVENT;
+
 	dev_priv->irq_mask = ~display_mask;
 
 	ibx_irq_pre_postinstall(dev_priv);
@@ -3482,17 +3485,6 @@ static void ilk_irq_postinstall(struct drm_i915_private *dev_priv)
 	ilk_hpd_detection_setup(dev_priv);
 
 	ibx_irq_postinstall(dev_priv);
-
-	if (IS_IRONLAKE_M(dev_priv)) {
-		/* Enable PCU event interrupts
-		 *
-		 * spinlocking not required here for correctness since interrupt
-		 * setup is guaranteed to run in single-threaded context. But we
-		 * need it to make the assert_spin_locked happy. */
-		spin_lock_irq(&dev_priv->irq_lock);
-		ilk_enable_display_irq(dev_priv, DE_PCU_EVENT);
-		spin_unlock_irq(&dev_priv->irq_lock);
-	}
 }
 
 void valleyview_enable_display_irqs(struct drm_i915_private *dev_priv)