[PATCH 1/5] drm/xe/oa/uapi: Expose media OA units

[Umesh Nerlige Ramappa]

On Tue, Jun 03, 2025 at 01:21:29PM -0700, Ashutosh Dixit wrote:
>On Xe2+ platforms, media engines are attached to "SCMI" OA media (OAM)
>units. One or more SCMI OAM units might be present on a platform. In
>addition there is another OAM unit for global events, called
>OAM-SAG. Performance metrics for media workloads can be obtained from these
>OAM units, similar to OAG.
>
>Expose these OAM units for userspace to use. OAM-SAG is exposed as an OA
>unit without any attached engines.
>
>Bspec: 70819, 67103, 63844, 72572, 74476, 61284
>
>v2: Fix xe_gt_WARN_ON in __hwe_oam_unit for < 12.7 platforms
>v3: Return XE_OA_UNIT_INVALID for < 12.7 to indicate no OAM units
>v4: Move xe_oa_print_oa_units() to separate patch
>v5: Introduce DRM_XE_OA_UNIT_TYPE_OAM_SAG
>
>Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
>---
> drivers/gpu/drm/xe/xe_oa.c | 68 ++++++++++++++++++++++++++++----------
> include/uapi/drm/xe_drm.h  |  3 ++
> 2 files changed, 54 insertions(+), 17 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
>index fb842fa0552e5..0de0d5a18df74 100644
>--- a/drivers/gpu/drm/xe/xe_oa.c
>+++ b/drivers/gpu/drm/xe/xe_oa.c
>@@ -43,6 +43,12 @@
> #define DEFAULT_POLL_PERIOD_NS (NSEC_PER_SEC / DEFAULT_POLL_FREQUENCY_HZ)
> #define XE_OA_UNIT_INVALID U32_MAX
>
>+enum xe_oam_unit_type {
>+	XE_OAM_UNIT_SAG,
>+	XE_OAM_UNIT_SCMI_0,
>+	XE_OAM_UNIT_SCMI_1,
>+};
>+
> enum xe_oa_submit_deps {
> 	XE_OA_SUBMIT_NO_DEPS,
> 	XE_OA_SUBMIT_ADD_DEPS,
>@@ -1881,6 +1887,7 @@ static bool engine_supports_oa_format(const struct xe_hw_engine *hwe, int type)
> 		return type == DRM_XE_OA_FMT_TYPE_OAG || type == DRM_XE_OA_FMT_TYPE_OAR ||
> 			type == DRM_XE_OA_FMT_TYPE_OAC || type == DRM_XE_OA_FMT_TYPE_PEC;
> 	case DRM_XE_OA_UNIT_TYPE_OAM:
>+	case DRM_XE_OA_UNIT_TYPE_OAM_SAG:
> 		return type == DRM_XE_OA_FMT_TYPE_OAM || type == DRM_XE_OA_FMT_TYPE_OAM_MPEC;
> 	default:
> 		return false;
>@@ -2448,20 +2455,38 @@ int xe_oa_register(struct xe_device *xe)
>
> static u32 num_oa_units_per_gt(struct xe_gt *gt)
> {
>-	return 1;
>+	if (!xe_gt_is_media_type(gt) || GRAPHICS_VER(gt_to_xe(gt)) < 20)
>+		return 1;
>+	else if (!IS_DGFX(gt_to_xe(gt)))
>+		return XE_OAM_UNIT_SCMI_0 + 1; /* SAG + SCMI_0 */
>+	else
>+		return XE_OAM_UNIT_SCMI_1 + 1; /* SAG + SCMI_0 + SCMI_1 */
> }
>
> static u32 __hwe_oam_unit(struct xe_hw_engine *hwe)
> {
>-	if (GRAPHICS_VERx100(gt_to_xe(hwe->gt)) >= 1270) {
>-		/*
>-		 * There's 1 SAMEDIA gt and 1 OAM per SAMEDIA gt. All media slices
>-		 * within the gt use the same OAM. All MTL/LNL SKUs list 1 SA MEDIA
>-		 */
>-		xe_gt_WARN_ON(hwe->gt, hwe->gt->info.type != XE_GT_TYPE_MEDIA);
>+	if (GRAPHICS_VERx100(gt_to_xe(hwe->gt)) < 1270)
>+		return XE_OA_UNIT_INVALID;
>
>+	xe_gt_WARN_ON(hwe->gt, !xe_gt_is_media_type(hwe->gt));
>+
>+	if (GRAPHICS_VER(gt_to_xe(hwe->gt)) < 20)
> 		return 0;
>-	}
>+	/*
>+	 * XE_OAM_UNIT_SAG has only GSCCS attached to it, but only on some platforms. Also
>+	 * GSCCS cannot be used to submit batches to program the OAM unit. Therefore we don't
>+	 * assign an OA unit to GSCCS. This means that XE_OAM_UNIT_SAG is exposed as an OA
>+	 * unit without attached engines. Fused off engines can also result in oa_unit's with
>+	 * num_engines == 0. OA streams can be opened on all OA units.
>+	 */
>+	else if (hwe->engine_id == XE_HW_ENGINE_GSCCS0)

You could just drop the case XE_ENGINE_CLASS_OTHER in caller 
(__hwe_oa_unit()) and then you dont need the XE_HW_ENGINE_GSCCS0 check 
here.

>+		return XE_OA_UNIT_INVALID;
>+	else if (!IS_DGFX(gt_to_xe(hwe->gt)))
>+		return XE_OAM_UNIT_SCMI_0;
>+	else if (hwe->class == XE_ENGINE_CLASS_VIDEO_DECODE)
>+		return (hwe->instance / 2 & 0x1) + 1;

should be same as (hwe->instance / 2) + 1;

>+	else if (hwe->class == XE_ENGINE_CLASS_VIDEO_ENHANCE)
>+		return (hwe->instance & 0x1) + 1;

same here, should be same as (hwe->instance + 1)

Thanks,
Umesh