drm/i915: Add test for invalid flag bits in whitelist entries

As per review feedback by Tvrtko, added a check that no invalid bits
are being set in the whitelist flags fields.

Also updated the read/write access definitions to make it clearer that
they are an enum field not a set of single bit flags.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
CC: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190712070745.35239-2-John.C.Harrison@Intel.com
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3ff659a..e14c9b7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2522,13 +2522,19 @@ enum i915_power_well_id {
 #define   RING_WAIT_SEMAPHORE	(1 << 10) /* gen6+ */
 
 #define RING_FORCE_TO_NONPRIV(base, i) _MMIO(((base) + 0x4D0) + (i) * 4)
-#define   RING_FORCE_TO_NONPRIV_RW		(0 << 28)    /* CFL+ & Gen11+ */
-#define   RING_FORCE_TO_NONPRIV_RD		(1 << 28)
-#define   RING_FORCE_TO_NONPRIV_WR		(2 << 28)
+#define   RING_FORCE_TO_NONPRIV_ACCESS_RW	(0 << 28)    /* CFL+ & Gen11+ */
+#define   RING_FORCE_TO_NONPRIV_ACCESS_RD	(1 << 28)
+#define   RING_FORCE_TO_NONPRIV_ACCESS_WR	(2 << 28)
+#define   RING_FORCE_TO_NONPRIV_ACCESS_INVALID	(3 << 28)
+#define   RING_FORCE_TO_NONPRIV_ACCESS_MASK	(3 << 28)
 #define   RING_FORCE_TO_NONPRIV_RANGE_1		(0 << 0)     /* CFL+ & Gen11+ */
 #define   RING_FORCE_TO_NONPRIV_RANGE_4		(1 << 0)
 #define   RING_FORCE_TO_NONPRIV_RANGE_16	(2 << 0)
 #define   RING_FORCE_TO_NONPRIV_RANGE_64	(3 << 0)
+#define   RING_FORCE_TO_NONPRIV_RANGE_MASK	(3 << 0)
+#define   RING_FORCE_TO_NONPRIV_MASK_VALID	\
+					(RING_FORCE_TO_NONPRIV_RANGE_MASK \
+					| RING_FORCE_TO_NONPRIV_ACCESS_MASK)
 #define   RING_MAX_NONPRIV_SLOTS  12
 
 #define GEN7_TLB_RD_ADDR	_MMIO(0x4700)