drm/xe: Minor cleanup in LRC handling

Properly define register fields and remove redundant
lower_32_bits().
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240507224255.5059-2-niranjana.vishwanathapura@intel.com

drivers/gpu/drm/xe/regs/xe_engine_regs.h

@@ -44,9 +44,10 @@
 #define GSCCS_RING_BASE				0x11a000
 
 #define RING_TAIL(base)				XE_REG((base) + 0x30)
+#define   TAIL_ADDR				REG_GENMASK(20, 3)
 
 #define RING_HEAD(base)				XE_REG((base) + 0x34)
-#define   HEAD_ADDR				0x001FFFFC
+#define   HEAD_ADDR				REG_GENMASK(20, 2)
 
 #define RING_START(base)			XE_REG((base) + 0x38)
 
@@ -136,7 +137,6 @@
 #define   RING_VALID_MASK			0x00000001
 #define   RING_VALID				0x00000001
 #define   STOP_RING				REG_BIT(8)
-#define   TAIL_ADDR				0x001FFFF8
 
 #define RING_CTX_TIMESTAMP(base)		XE_REG((base) + 0x3a8)
 #define CSBE_DEBUG_STATUS(base)			XE_REG((base) + 0x3fc)

drivers/gpu/drm/xe/xe_lrc.c

@@ -1354,7 +1354,7 @@ struct xe_lrc_snapshot *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
 	if (!snapshot)
 		return NULL;
 
-	snapshot->context_desc = lower_32_bits(xe_lrc_ggtt_addr(lrc));
+	snapshot->context_desc = xe_lrc_ggtt_addr(lrc);
 	snapshot->head = xe_lrc_ring_head(lrc);
 	snapshot->tail.internal = lrc->ring.tail;
 	snapshot->tail.memory = xe_lrc_read_ctx_reg(lrc, CTX_RING_TAIL);