Re: [PATCH v2 4/8] drm/xe: add function to convert xe hw engine class to user class

[Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>]

On Thu, Nov 21, 2024 at 12:09:00PM +0530, Riana Tauro wrote:
>Avoid duplication of code in PMU by moving hw engine to user class
>to a separate function. Refactor existing code to use
>this new function.
>
>v2: replace with array (Umesh)
>    fix commit message (Rodrigo)
>
>Signed-off-by: Riana Tauro <riana.tauro@intel.com>
>---
> drivers/gpu/drm/xe/xe_hw_engine.c | 21 +++++++++++++++++++++
> drivers/gpu/drm/xe/xe_hw_engine.h |  1 +
> drivers/gpu/drm/xe/xe_query.c     | 12 ++----------
> 3 files changed, 24 insertions(+), 10 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
>index c4b0dc3be39c..c41b4038dbb3 100644
>--- a/drivers/gpu/drm/xe/xe_hw_engine.c
>+++ b/drivers/gpu/drm/xe/xe_hw_engine.c
>@@ -979,6 +979,27 @@ const char *xe_hw_engine_class_to_str(enum xe_engine_class class)
> 	return NULL;
> }
>
>+/**
>+ * xe_hw_engine_to_user_class - converts xe hw engine to user engine class
>+ * @engine_class: hw engine class
>+ *
>+ * Returns: user engine class on success, -1 on error

1) Depends on what you want to return on error since you return u16. If 
the WARN_ON fires below, you may just want to return a default like:
DRM_XE_ENGINE_CLASS_RENDER or 0 and change the comment above 
accordingly.

2) Returning -1 means use an int return type and make sure all callers 
check for the return and act accordingly.

I would recommend 1.

>+ */
>+u16 xe_hw_engine_to_user_class(enum xe_engine_class engine_class)

since now this is a xe_hw_engine api, pass the hwe to this function 
instead of the engine_class.

>+{
>+	const u16 xe_to_user_engine_class[] = {
>+		[XE_ENGINE_CLASS_RENDER] = DRM_XE_ENGINE_CLASS_RENDER,
>+		[XE_ENGINE_CLASS_COPY] = DRM_XE_ENGINE_CLASS_COPY,
>+		[XE_ENGINE_CLASS_VIDEO_DECODE] = DRM_XE_ENGINE_CLASS_VIDEO_DECODE,
>+		[XE_ENGINE_CLASS_VIDEO_ENHANCE] = DRM_XE_ENGINE_CLASS_VIDEO_ENHANCE,
>+		[XE_ENGINE_CLASS_COMPUTE] = DRM_XE_ENGINE_CLASS_COMPUTE,
>+	};
>+
>+	WARN_ON(engine_class >= ARRAY_SIZE(xe_to_user_engine_class));

Revisiting this, it should not index into the array if the engine_class 
is invalid.

	if(WARN_ON(engine_class >= ARRAY_SIZE(xe_to_user_engine_class)))
		return <something>;

Thanks,
Umesh


>+
>+	return xe_to_user_engine_class[engine_class];
>+}
>+
> u64 xe_hw_engine_read_timestamp(struct xe_hw_engine *hwe)
> {
> 	return xe_mmio_read64_2x32(&hwe->gt->mmio, RING_TIMESTAMP(hwe->mmio_base));
>diff --git a/drivers/gpu/drm/xe/xe_hw_engine.h b/drivers/gpu/drm/xe/xe_hw_engine.h
>index 6b5f9fa2a594..06b39cb1a434 100644
>--- a/drivers/gpu/drm/xe/xe_hw_engine.h
>+++ b/drivers/gpu/drm/xe/xe_hw_engine.h
>@@ -74,6 +74,7 @@ static inline bool xe_hw_engine_is_valid(struct xe_hw_engine *hwe)
>
> const char *xe_hw_engine_class_to_str(enum xe_engine_class class);
> u64 xe_hw_engine_read_timestamp(struct xe_hw_engine *hwe);
>+u16 xe_hw_engine_to_user_class(enum xe_engine_class engine_class);
> enum xe_force_wake_domains xe_hw_engine_to_fw_domain(struct xe_hw_engine *hwe);
>
> void xe_hw_engine_mmio_write32(struct xe_hw_engine *hwe, struct xe_reg reg, u32 val);
>diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
>index 3eda616f1502..a260c43f13f4 100644
>--- a/drivers/gpu/drm/xe/xe_query.c
>+++ b/drivers/gpu/drm/xe/xe_query.c
>@@ -27,14 +27,6 @@
> #include "xe_ttm_vram_mgr.h"
> #include "xe_wa.h"
>
>-static const u16 xe_to_user_engine_class[] = {
>-	[XE_ENGINE_CLASS_RENDER] = DRM_XE_ENGINE_CLASS_RENDER,
>-	[XE_ENGINE_CLASS_COPY] = DRM_XE_ENGINE_CLASS_COPY,
>-	[XE_ENGINE_CLASS_VIDEO_DECODE] = DRM_XE_ENGINE_CLASS_VIDEO_DECODE,
>-	[XE_ENGINE_CLASS_VIDEO_ENHANCE] = DRM_XE_ENGINE_CLASS_VIDEO_ENHANCE,
>-	[XE_ENGINE_CLASS_COMPUTE] = DRM_XE_ENGINE_CLASS_COMPUTE,
>-};
>-
> static const enum xe_engine_class user_to_xe_engine_class[] = {
> 	[DRM_XE_ENGINE_CLASS_RENDER] = XE_ENGINE_CLASS_RENDER,
> 	[DRM_XE_ENGINE_CLASS_COPY] = XE_ENGINE_CLASS_COPY,
>@@ -207,7 +199,7 @@ static int query_engines(struct xe_device *xe,
> 				continue;
>
> 			engines->engines[i].instance.engine_class =
>-				xe_to_user_engine_class[hwe->class];
>+				xe_hw_engine_to_user_class(hwe->class);
> 			engines->engines[i].instance.engine_instance =
> 				hwe->logical_instance;
> 			engines->engines[i].instance.gt_id = gt->info.id;
>@@ -678,7 +670,7 @@ static int query_oa_units(struct xe_device *xe,
> 				if (!xe_hw_engine_is_reserved(hwe) &&
> 				    xe_oa_unit_id(hwe) == u->oa_unit_id) {
> 					du->eci[j].engine_class =
>-						xe_to_user_engine_class[hwe->class];
>+						xe_hw_engine_to_user_class(hwe->class);
> 					du->eci[j].engine_instance = hwe->logical_instance;
> 					du->eci[j].gt_id = gt->info.id;
> 					j++;
>-- 
>2.40.0
>