[PATCH v3 1/4] drm/xe: Save CTX_TIMESTAMP mmio value instead of LRC value

[Umesh Nerlige Ramappa]

For determining actual job execution time, save the current value of the
CTX_TIMESTAMP register rather than the value saved in LRC since the
current register value is the closest to the start time of the job.

v2: Define MI_STORE_REGISTER_MEM to fix compile error

Fixes: 65921374c48f ("drm/xe: Emit ctx timestamp copy in ring ops")
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/instructions/xe_mi_commands.h | 4 ++++
 drivers/gpu/drm/xe/xe_lrc.c                      | 2 +-
 drivers/gpu/drm/xe/xe_ring_ops.c                 | 7 ++-----
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/xe/instructions/xe_mi_commands.h b/drivers/gpu/drm/xe/instructions/xe_mi_commands.h
index eba582058d55..9153a7cd2ceb 100644
--- a/drivers/gpu/drm/xe/instructions/xe_mi_commands.h
+++ b/drivers/gpu/drm/xe/instructions/xe_mi_commands.h
@@ -62,6 +62,10 @@
 #define MI_LOAD_REGISTER_MEM		(__MI_INSTR(0x29) | XE_INSTR_NUM_DW(4))
 #define   MI_LRM_USE_GGTT		REG_BIT(22)
 
+#define MI_STORE_REGISTER_MEM		(__MI_INSTR(0x24) | XE_INSTR_NUM_DW(4))
+#define   MI_SRM_USE_GGTT		REG_BIT(22)
+#define   MI_SRM_ADD_CS_OFFSET		REG_BIT(19)
+
 #define MI_LOAD_REGISTER_REG		(__MI_INSTR(0x2a) | XE_INSTR_NUM_DW(3))
 #define   MI_LRR_DST_CS_MMIO		REG_BIT(19)
 #define   MI_LRR_SRC_CS_MMIO		REG_BIT(18)
diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
index 855c8acaf3f1..015b00a73c0b 100644
--- a/drivers/gpu/drm/xe/xe_lrc.c
+++ b/drivers/gpu/drm/xe/xe_lrc.c
@@ -687,7 +687,7 @@ static inline u32 __xe_lrc_start_seqno_offset(struct xe_lrc *lrc)
 
 static u32 __xe_lrc_ctx_job_timestamp_offset(struct xe_lrc *lrc)
 {
-	/* The start seqno is stored in the driver-defined portion of PPHWSP */
+	/* This is stored in the driver-defined portion of PPHWSP */
 	return xe_lrc_pphwsp_offset(lrc) + LRC_CTX_JOB_TIMESTAMP_OFFSET;
 }
 
diff --git a/drivers/gpu/drm/xe/xe_ring_ops.c b/drivers/gpu/drm/xe/xe_ring_ops.c
index a7582b097ae6..bc1689db4cd7 100644
--- a/drivers/gpu/drm/xe/xe_ring_ops.c
+++ b/drivers/gpu/drm/xe/xe_ring_ops.c
@@ -234,13 +234,10 @@ static u32 get_ppgtt_flag(struct xe_sched_job *job)
 
 static int emit_copy_timestamp(struct xe_lrc *lrc, u32 *dw, int i)
 {
-	dw[i++] = MI_COPY_MEM_MEM | MI_COPY_MEM_MEM_SRC_GGTT |
-		MI_COPY_MEM_MEM_DST_GGTT;
+	dw[i++] = MI_STORE_REGISTER_MEM | MI_SRM_USE_GGTT | MI_SRM_ADD_CS_OFFSET;
+	dw[i++] = RING_CTX_TIMESTAMP(0).addr;
 	dw[i++] = xe_lrc_ctx_job_timestamp_ggtt_addr(lrc);
 	dw[i++] = 0;
-	dw[i++] = xe_lrc_ctx_timestamp_ggtt_addr(lrc);
-	dw[i++] = 0;
-	dw[i++] = MI_NOOP;
 
 	return i;
 }
-- 
2.43.0