drm/xe/lrc: Add helper to capture context timestamp

Add a helper to capture CTX_TIMESTAMP from the context image so it can
be used to calculate the runtime.

v2: Add kernel-doc to clarify expectation from caller

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240517204310.88854-4-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

diff --git a/drivers/gpu/drm/xe/regs/xe_lrc_layout.h b/drivers/gpu/drm/xe/regs/xe_lrc_layout.h
index e6ca8bbda8f4e6b6cf66fdc33e3c7b508cd46c39..045dfd09db99932c7bb1a76a68bb8fb331777703 100644 (file)
--- a/drivers/gpu/drm/xe/regs/xe_lrc_layout.h
+++ b/drivers/gpu/drm/xe/regs/xe_lrc_layout.h
@@ -11,6 +11,7 @@
 #define CTX_RING_TAIL                  (0x06 + 1)
 #define CTX_RING_START                 (0x08 + 1)
 #define CTX_RING_CTL                   (0x0a + 1)
+#define CTX_TIMESTAMP                  (0x22 + 1)
 #define CTX_INDIRECT_RING_STATE                (0x26 + 1)
 #define CTX_PDP0_UDW                   (0x30 + 1)
 #define CTX_PDP0_LDW                   (0x32 + 1)

diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
index 9b0a4078add33ebf7f2d534590c3cb2b70736ebc..f679cb9aaea7ea7772027c0b714349cdba9b085a 100644 (file)
--- a/drivers/gpu/drm/xe/xe_lrc.c
+++ b/drivers/gpu/drm/xe/xe_lrc.c
@@ -844,6 +844,7 @@ int xe_lrc_init(struct xe_lrc *lrc, struct xe_hw_engine *hwe,
        lrc->tile = gt_to_tile(hwe->gt);
        lrc->ring.size = ring_size;
        lrc->ring.tail = 0;
+       lrc->ctx_timestamp = 0;
 
        xe_hw_fence_ctx_init(&lrc->fence_ctx, hwe->gt,
                             hwe->fence_irq, hwe->name);
@@ -898,6 +899,8 @@ int xe_lrc_init(struct xe_lrc *lrc, struct xe_hw_engine *hwe,
                                     RING_CTL_SIZE(lrc->ring.size) | RING_VALID);
        }
 
+       xe_lrc_write_ctx_reg(lrc, CTX_TIMESTAMP, 0);
+
        if (xe->info.has_asid && vm)
                xe_lrc_write_ctx_reg(lrc, PVC_CTX_ASID, vm->usm.asid);
 
@@ -1576,3 +1579,12 @@ void xe_lrc_snapshot_free(struct xe_lrc_snapshot *snapshot)
                xe_bo_put(snapshot->lrc_bo);
        kfree(snapshot);
 }
+
+u32 xe_lrc_update_timestamp(struct xe_lrc *lrc, u32 *old_ts)
+{
+       *old_ts = lrc->ctx_timestamp;
+
+       lrc->ctx_timestamp = xe_lrc_read_ctx_reg(lrc, CTX_TIMESTAMP);
+
+       return lrc->ctx_timestamp;
+}

diff --git a/drivers/gpu/drm/xe/xe_lrc.h b/drivers/gpu/drm/xe/xe_lrc.h
index e0e841963c23e923c770317984e10873ffff4a0a..b9da1031083b3dcc1580721bfb6ca9c7287247b4 100644 (file)
--- a/drivers/gpu/drm/xe/xe_lrc.h
+++ b/drivers/gpu/drm/xe/xe_lrc.h
@@ -66,4 +66,18 @@ void xe_lrc_snapshot_capture_delayed(struct xe_lrc_snapshot *snapshot);
 void xe_lrc_snapshot_print(struct xe_lrc_snapshot *snapshot, struct drm_printer *p);
 void xe_lrc_snapshot_free(struct xe_lrc_snapshot *snapshot);
 
+/**
+ * xe_lrc_update_timestamp - readout LRC timestamp and update cached value
+ * @lrc: logical ring context for this exec queue
+ * @old_ts: pointer where to save the previous timestamp
+ *
+ * Read the current timestamp for this LRC and update the cached value. The
+ * previous cached value is also returned in @old_ts so the caller can calculate
+ * the delta between 2 updates. Note that this is not intended to be called from
+ * any place, but just by the paths updating the drm client utilization.
+ *
+ * Returns the current LRC timestamp
+ */
+u32 xe_lrc_update_timestamp(struct xe_lrc *lrc, u32 *old_ts);
+
 #endif

diff --git a/drivers/gpu/drm/xe/xe_lrc_types.h b/drivers/gpu/drm/xe/xe_lrc_types.h
index cdbf03faef15fbe32c6c0d42448b39286bc38b54..0fa055da6b27b8fdee2431b54c3ca84963948e6b 100644 (file)
--- a/drivers/gpu/drm/xe/xe_lrc_types.h
+++ b/drivers/gpu/drm/xe/xe_lrc_types.h
@@ -45,6 +45,9 @@ struct xe_lrc {
 
        /** @fence_ctx: context for hw fence */
        struct xe_hw_fence_ctx fence_ctx;
+
+       /** @ctx_timestamp: readout value of CTX_TIMESTAMP on last update */
+       u32 ctx_timestamp;
 };
 
 struct xe_lrc_snapshot;