drm/i915/skl: Expose DC5/DC6 entry counts

The CSR firmware expose two counters, handy to check if we are indeed
entering DC5/DC6.

v2: Rebase
v3: Take RPM ref before reading (Imre)

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> (v1)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446220412-32574-1-git-send-email-mika.kuoppala@intel.com
Tested-by: Daniel Stone <daniels@collabora.com> # SKL
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e8f1d42..bbfc9d9 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5697,6 +5697,10 @@
 #define GAMMA_MODE_MODE_12BIT	(2 << 0)
 #define GAMMA_MODE_MODE_SPLIT	(3 << 0)
 
+/* DMC/CSR */
+#define SKL_CSR_DC3_DC5_COUNT	0x80030
+#define SKL_CSR_DC5_DC6_COUNT	0x8002C
+
 /* interrupts */
 #define DE_MASTER_IRQ_CONTROL   (1 << 31)
 #define DE_SPRITEB_FLIP_DONE    (1 << 29)