drm/i915: reuse Ivy Bridge interrupts code for Haswell

Haswell interrupts are mostly similar with Ivy Bridge, so we share same
routines with it.

This patch also simplifies the vblank counter handling for all the Gen5+
architectures.
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -2583,8 +2583,7 @@ void intel_irq_init(struct drm_device *dev)
 
 	dev->driver->get_vblank_counter = i915_get_vblank_counter;
 	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
-	if (IS_G4X(dev) || IS_GEN5(dev) || IS_GEN6(dev) || IS_IVYBRIDGE(dev) ||
-	    IS_VALLEYVIEW(dev)) {
+	if (IS_G4X(dev) || INTEL_INFO(dev)->gen >= 5) {
 		dev->max_vblank_count = 0xffffffff; /* full 32 bit counter */
 		dev->driver->get_vblank_counter = gm45_get_vblank_counter;
 	}
@@ -2610,6 +2609,14 @@ void intel_irq_init(struct drm_device *dev)
 		dev->driver->irq_uninstall = ironlake_irq_uninstall;
 		dev->driver->enable_vblank = ivybridge_enable_vblank;
 		dev->driver->disable_vblank = ivybridge_disable_vblank;
+	} else if (IS_HASWELL(dev)) {
+		/* Share interrupts handling with IVB */
+		dev->driver->irq_handler = ivybridge_irq_handler;
+		dev->driver->irq_preinstall = ironlake_irq_preinstall;
+		dev->driver->irq_postinstall = ivybridge_irq_postinstall;
+		dev->driver->irq_uninstall = ironlake_irq_uninstall;
+		dev->driver->enable_vblank = ivybridge_enable_vblank;
+		dev->driver->disable_vblank = ivybridge_disable_vblank;
 	} else if (HAS_PCH_SPLIT(dev)) {
 		dev->driver->irq_handler = ironlake_irq_handler;
 		dev->driver->irq_preinstall = ironlake_irq_preinstall;