[PATCH 6.18.y 1/6] drm/xe/lrc: Refactor out engine id to hwe conversion

[Sasha Levin <sashal@kernel.org>]

From: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

[ Upstream commit e3a9c46fc3a29b8d7f62a7bd73bf20975037dc82 ]

We need to define more helpers that read engine ID specific register, so
move that logic outside of get_ctx_timestamp().

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Link: https://patch.msgid.link/20260507162016.3888309-20-umesh.nerlige.ramappa@intel.com
Stable-dep-of: 31e243756162 ("drm/xe/rtp: Maintain OA whitelists separately")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/xe/xe_lrc.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
index 9f29dbe890f6..17f31b032216 100644
--- a/drivers/gpu/drm/xe/xe_lrc.c
+++ b/drivers/gpu/drm/xe/xe_lrc.c
@@ -2324,17 +2324,27 @@ void xe_lrc_snapshot_free(struct xe_lrc_snapshot *snapshot)
 	kfree(snapshot);
 }
 
-static int get_ctx_timestamp(struct xe_lrc *lrc, u32 engine_id, u64 *reg_ctx_ts)
+static struct xe_hw_engine *engine_id_to_hwe(struct xe_gt *gt, u32 engine_id)
 {
 	u16 class = REG_FIELD_GET(ENGINE_CLASS_ID, engine_id);
 	u16 instance = REG_FIELD_GET(ENGINE_INSTANCE_ID, engine_id);
+	struct xe_hw_engine *hwe = xe_gt_hw_engine(gt, class, instance, false);
+
+	if (xe_gt_WARN_ONCE(gt, !hwe || xe_hw_engine_is_reserved(hwe),
+			    "Unexpected engine class:instance %d:%d for utilization\n",
+			    class, instance))
+		return NULL;
+
+	return hwe;
+}
+
+static int get_ctx_timestamp(struct xe_lrc *lrc, u32 engine_id, u64 *reg_ctx_ts)
+{
 	struct xe_hw_engine *hwe;
 	u64 val;
 
-	hwe = xe_gt_hw_engine(lrc->gt, class, instance, false);
-	if (xe_gt_WARN_ONCE(lrc->gt, !hwe || xe_hw_engine_is_reserved(hwe),
-			    "Unexpected engine class:instance %d:%d for context utilization\n",
-			    class, instance))
+	hwe = engine_id_to_hwe(lrc->gt, engine_id);
+	if (!hwe)
 		return -1;
 
 	if (lrc_to_xe(lrc)->info.has_64bit_timestamp)
-- 
2.53.0