drm/i915: Cleanup South Error Interrupts

Cleanup and parametrize the handling of South Error Interrupts (SERR_INT).
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1507630626-23806-6-git-send-email-mika.kahola@intel.com

drivers/gpu/drm/i915/i915_irq.c

@@ -2252,18 +2252,14 @@ static void ivb_err_int_handler(struct drm_i915_private *dev_priv)
 static void cpt_serr_int_handler(struct drm_i915_private *dev_priv)
 {
 	u32 serr_int = I915_READ(SERR_INT);
+	enum pipe pipe;
 
 	if (serr_int & SERR_INT_POISON)
 		DRM_ERROR("PCH poison interrupt\n");
 
-	if (serr_int & SERR_INT_TRANS_A_FIFO_UNDERRUN)
-		intel_pch_fifo_underrun_irq_handler(dev_priv, PIPE_A);
-
-	if (serr_int & SERR_INT_TRANS_B_FIFO_UNDERRUN)
-		intel_pch_fifo_underrun_irq_handler(dev_priv, PIPE_B);
-
-	if (serr_int & SERR_INT_TRANS_C_FIFO_UNDERRUN)
-		intel_pch_fifo_underrun_irq_handler(dev_priv, PIPE_C);
+	for_each_pipe(dev_priv, pipe)
+		if (serr_int & SERR_INT_TRANS_FIFO_UNDERRUN(pipe))
+			intel_pch_fifo_underrun_irq_handler(dev_priv, pipe);
 
 	I915_WRITE(SERR_INT, serr_int);
 }

drivers/gpu/drm/i915/i915_reg.h

@@ -7182,9 +7182,6 @@ enum {
 
 #define SERR_INT			_MMIO(0xc4040)
 #define  SERR_INT_POISON		(1<<31)
-#define  SERR_INT_TRANS_C_FIFO_UNDERRUN	(1<<6)
-#define  SERR_INT_TRANS_B_FIFO_UNDERRUN	(1<<3)
-#define  SERR_INT_TRANS_A_FIFO_UNDERRUN	(1<<0)
 #define  SERR_INT_TRANS_FIFO_UNDERRUN(pipe)	(1<<((pipe)*3))
 
 /* digital port hotplug */