drm/i915: Implement GPU reset on i965

This patch puts in place the machinery to attempt to reset the GPU. This
will be used when attempting to recover from a GPU hang.

Signed-off-by: Owain G. Ainsworth <oga@openbsd.org>
Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6345bf2..f3d4139 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -85,6 +85,10 @@
 #define   I915_GC_RENDER_CLOCK_200_MHZ	(1 << 0)
 #define   I915_GC_RENDER_CLOCK_333_MHZ	(4 << 0)
 #define LBB	0xf4
+#define GDRST 0xc0
+#define  GDRST_FULL	(0<<2)
+#define  GDRST_RENDER	(1<<2)
+#define  GDRST_MEDIA	(3<<2)
 
 /* VGA stuff */