[Intel-gfx] [PATCH 2/2] drm/i915: Simplify the IVB interrupt handler

[Chris Wilson]

Reduce the number of reads and writes required for handling a single
interrupt.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_irq.c |   94 ++++++++++++++++-----------------------
 1 file changed, 38 insertions(+), 56 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 7d1fc62..72c85f0 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -533,14 +533,11 @@ out:
 	return ret;
 }
 
-static void pch_irq_handler(struct drm_device *dev)
+static void pch_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 pch_iir;
 	int pipe;
 
-	pch_iir = I915_READ(SDEIIR);
-
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -580,26 +577,15 @@ static irqreturn_t ivybridge_irq_handler(DRM_IRQ_ARGS)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	int ret = IRQ_NONE;
-	u32 de_iir, gt_iir, de_ier, pch_iir, pm_iir;
+	u32 de_iir, gt_iir, de_ier, pm_iir;
 	struct drm_i915_master_private *master_priv;
+	int i;
 
 	atomic_inc(&dev_priv->irq_received);
 
 	/* disable master interrupt before clearing iir  */
 	de_ier = I915_READ(DEIER);
 	I915_WRITE(DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
-	POSTING_READ(DEIER);
-
-	de_iir = I915_READ(DEIIR);
-	gt_iir = I915_READ(GTIIR);
-	pch_iir = I915_READ(SDEIIR);
-	pm_iir = I915_READ(GEN6_PMIIR);
-
-	if (de_iir == 0 && gt_iir == 0 && pch_iir == 0 && pm_iir == 0)
-		goto done;
-
-	ret = IRQ_HANDLED;
 
 	if (dev->primary->master) {
 		master_priv = dev->primary->master->driver_priv;
@@ -608,56 +594,52 @@ static irqreturn_t ivybridge_irq_handler(DRM_IRQ_ARGS)
 				READ_BREADCRUMB(dev_priv);
 	}
 
-	snb_gt_irq_handler(dev, dev_priv, gt_iir);
-
-	if (de_iir & DE_GSE_IVB)
-		intel_opregion_gse_intr(dev);
-
-	if (de_iir & DE_PLANEA_FLIP_DONE_IVB) {
-		intel_prepare_page_flip(dev, 0);
-		intel_finish_page_flip_plane(dev, 0);
-	}
-
-	if (de_iir & DE_PLANEB_FLIP_DONE_IVB) {
-		intel_prepare_page_flip(dev, 1);
-		intel_finish_page_flip_plane(dev, 1);
+	gt_iir = I915_READ(GTIIR);
+	if (gt_iir) {
+		snb_gt_irq_handler(dev, dev_priv, gt_iir);
+		I915_WRITE(GTIIR, gt_iir);
 	}
 
-	if (de_iir & DE_PLANEC_FLIP_DONE_IVB) {
-		intel_prepare_page_flip(dev, 2);
-		intel_finish_page_flip_plane(dev, 2);
-	}
+	de_iir = I915_READ(DEIIR);
+	if (de_iir) {
+		if (de_iir & DE_GSE_IVB)
+			intel_opregion_gse_intr(dev);
+
+		for (i = 0; i < 3; i++) {
+			if (de_iir & (DE_PLANEA_FLIP_DONE_IVB << (5 * i))) {
+				intel_prepare_page_flip(dev, i);
+				intel_finish_page_flip_plane(dev, i);
+			}
+			if (de_iir & (DE_PIPEA_VBLANK_IVB << (5 * i)))
+				drm_handle_vblank(dev, i);
+		}
 
-	if (de_iir & DE_PIPEA_VBLANK_IVB)
-		drm_handle_vblank(dev, 0);
+		/* check event from PCH */
+		if (de_iir & DE_PCH_EVENT_IVB) {
+			u32 pch_iir = I915_READ(SDEIIR);
 
-	if (de_iir & DE_PIPEB_VBLANK_IVB)
-		drm_handle_vblank(dev, 1);
+			if (pch_iir & SDE_HOTPLUG_MASK_CPT)
+				queue_work(dev_priv->wq, &dev_priv->hotplug_work);
+			pch_irq_handler(dev, pch_iir);
 
-	if (de_iir & DE_PIPEC_VBLANK_IVB)
-		drm_handle_vblank(dev, 2);
+			/* clear PCH hotplug event before clear CPU irq */
+			I915_WRITE(SDEIIR, pch_iir);
+		}
 
-	/* check event from PCH */
-	if (de_iir & DE_PCH_EVENT_IVB) {
-		if (pch_iir & SDE_HOTPLUG_MASK_CPT)
-			queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-		pch_irq_handler(dev);
+		I915_WRITE(DEIIR, de_iir);
 	}
 
-	if (pm_iir & GEN6_PM_DEFERRED_EVENTS)
-		gen6_queue_rps_work(dev_priv, pm_iir);
-
-	/* should clear PCH hotplug event before clear CPU irq */
-	I915_WRITE(SDEIIR, pch_iir);
-	I915_WRITE(GTIIR, gt_iir);
-	I915_WRITE(DEIIR, de_iir);
-	I915_WRITE(GEN6_PMIIR, pm_iir);
+	pm_iir = I915_READ(GEN6_PMIIR);
+	if (pm_iir) {
+		if (pm_iir & GEN6_PM_DEFERRED_EVENTS)
+			gen6_queue_rps_work(dev_priv, pm_iir);
+		I915_WRITE(GEN6_PMIIR, pm_iir);
+	}
 
-done:
 	I915_WRITE(DEIER, de_ier);
 	POSTING_READ(DEIER);
 
-	return ret;
+	return IRQ_HANDLED;
 }
 
 static void ilk_gt_irq_handler(struct drm_device *dev,
@@ -737,7 +719,7 @@ static irqreturn_t ironlake_irq_handler(DRM_IRQ_ARGS)
 	if (de_iir & DE_PCH_EVENT) {
 		if (pch_iir & hotplug_mask)
 			queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-		pch_irq_handler(dev);
+		pch_irq_handler(dev, pch_iir);
 	}
 
 	if (de_iir & DE_PCU_EVENT) {
-- 
1.7.10