drm/i915: Optimize pipe irq handling on bdw

We have a per-pipe bit in the master irq control register, so use it.
This allows us to drop the masks for aggregate interrupt bits and be a
bit more explicit in the code. It also removes one indentation level.

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -1749,6 +1749,7 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
 	u32 master_ctl;
 	irqreturn_t ret = IRQ_NONE;
 	uint32_t tmp = 0;
+	enum pipe pipe;
 
 	atomic_inc(&dev_priv->irq_received);
 
@@ -1777,31 +1778,28 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
 		}
 	}
 
-	if (master_ctl & GEN8_DE_IRQS) {
-		int de_ret = 0;
-		int pipe;
-		for_each_pipe(pipe) {
-			uint32_t pipe_iir;
-
-			pipe_iir = I915_READ(GEN8_DE_PIPE_IIR(pipe));
-			if (pipe_iir & GEN8_PIPE_VBLANK)
-				drm_handle_vblank(dev, pipe);
+	for_each_pipe(pipe) {
+		uint32_t pipe_iir;
 
-			if (pipe_iir & GEN8_PIPE_FLIP_DONE) {
-				intel_prepare_page_flip(dev, pipe);
-				intel_finish_page_flip_plane(dev, pipe);
-			}
+		if (!(master_ctl & GEN8_DE_PIPE_IRQ(pipe)))
+			continue;
 
-			if (pipe_iir & GEN8_DE_PIPE_IRQ_ERRORS)
-				DRM_ERROR("Errors on pipe %c\n", 'A' + pipe);
+		pipe_iir = I915_READ(GEN8_DE_PIPE_IIR(pipe));
+		if (pipe_iir & GEN8_PIPE_VBLANK)
+			drm_handle_vblank(dev, pipe);
 
-			if (pipe_iir) {
-				de_ret++;
-				ret = IRQ_HANDLED;
-				I915_WRITE(GEN8_DE_PIPE_IIR(pipe), pipe_iir);
-			}
+		if (pipe_iir & GEN8_PIPE_FLIP_DONE) {
+			intel_prepare_page_flip(dev, pipe);
+			intel_finish_page_flip_plane(dev, pipe);
 		}
-		if (!de_ret)
+
+		if (pipe_iir & GEN8_DE_PIPE_IRQ_ERRORS)
+			DRM_ERROR("Errors on pipe %c\n", 'A' + pipe);
+
+		if (pipe_iir) {
+			ret = IRQ_HANDLED;
+			I915_WRITE(GEN8_DE_PIPE_IIR(pipe), pipe_iir);
+		} else
 			DRM_ERROR("The master control interrupt lied (DE PIPE)!\n");
 	}
 

drivers/gpu/drm/i915/i915_reg.h

@@ -4031,15 +4031,12 @@
 #define  GEN8_DE_PIPE_C_IRQ		(1<<18)
 #define  GEN8_DE_PIPE_B_IRQ		(1<<17)
 #define  GEN8_DE_PIPE_A_IRQ		(1<<16)
+#define  GEN8_DE_PIPE_IRQ(pipe)		(1<<(16+pipe))
 #define  GEN8_GT_VECS_IRQ		(1<<6)
 #define  GEN8_GT_VCS2_IRQ		(1<<3)
 #define  GEN8_GT_VCS1_IRQ		(1<<2)
 #define  GEN8_GT_BCS_IRQ		(1<<1)
 #define  GEN8_GT_RCS_IRQ		(1<<0)
-/* Lazy definition */
-#define  GEN8_GT_IRQS			0x000000ff
-#define  GEN8_DE_IRQS			0x01ff0000
-#define  GEN8_RSVD_IRQS			0xB700ff00
 
 #define GEN8_GT_ISR(which) (0x44300 + (0x10 * (which)))
 #define GEN8_GT_IMR(which) (0x44304 + (0x10 * (which)))