Re: [Intel-gfx] [PATCH 4/4] drm/i915/gt: nuke gen6_hw_id

[Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>]

On 21/07/2021 00:20, Lucas De Marchi wrote:
> This is only used by GRAPHICS_VER == 6 and GRAPHICS_VER == 7. All other
> recent platforms do not depend on this field, so it doesn't make much
> sense to keep it generic like that. Instead, just do a mapping from
> engine class to HW ID in the single place that is needed.
>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/gt/intel_engine_cs.c    | 6 ------
>   drivers/gpu/drm/i915/gt/intel_engine_types.h | 8 --------
>   drivers/gpu/drm/i915/i915_reg.h              | 4 +++-
>   3 files changed, 3 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> index 508221de411c..0a04e8d90e9e 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> @@ -42,7 +42,6 @@
>   
>   #define MAX_MMIO_BASES 3
>   struct engine_info {
> -	u8 gen6_hw_id;
>   	u8 class;
>   	u8 instance;
>   	/* mmio bases table *must* be sorted in reverse graphics_ver order */
> @@ -54,7 +53,6 @@ struct engine_info {
>   
>   static const struct engine_info intel_engines[] = {
>   	[RCS0] = {
> -		.gen6_hw_id = RCS0_HW,
>   		.class = RENDER_CLASS,
>   		.instance = 0,
>   		.mmio_bases = {
> @@ -62,7 +60,6 @@ static const struct engine_info intel_engines[] = {
>   		},
>   	},
>   	[BCS0] = {
> -		.gen6_hw_id = BCS0_HW,
>   		.class = COPY_ENGINE_CLASS,
>   		.instance = 0,
>   		.mmio_bases = {
> @@ -70,7 +67,6 @@ static const struct engine_info intel_engines[] = {
>   		},
>   	},
>   	[VCS0] = {
> -		.gen6_hw_id = VCS0_HW,
>   		.class = VIDEO_DECODE_CLASS,
>   		.instance = 0,
>   		.mmio_bases = {
> @@ -102,7 +98,6 @@ static const struct engine_info intel_engines[] = {
>   		},
>   	},
>   	[VECS0] = {
> -		.gen6_hw_id = VECS0_HW,
>   		.class = VIDEO_ENHANCEMENT_CLASS,
>   		.instance = 0,
>   		.mmio_bases = {
> @@ -290,7 +285,6 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id)
>   	engine->i915 = i915;
>   	engine->gt = gt;
>   	engine->uncore = gt->uncore;
> -	engine->gen6_hw_id = info->gen6_hw_id;
>   	guc_class = engine_class_to_guc_class(info->class);
>   	engine->guc_id = MAKE_GUC_ID(guc_class, info->instance);
>   	engine->mmio_base = __engine_mmio_base(i915, info->mmio_bases);
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> index 266422d8d1b1..64330bfb7641 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> @@ -28,13 +28,6 @@
>   #include "intel_wakeref.h"
>   #include "intel_workarounds_types.h"
>   
> -/* Legacy HW Engine ID */
> -
> -#define RCS0_HW		0
> -#define VCS0_HW		1
> -#define BCS0_HW		2
> -#define VECS0_HW	3
> -
>   /* Gen11+ HW Engine class + instance */
>   #define RENDER_CLASS		0
>   #define VIDEO_DECODE_CLASS	1
> @@ -268,7 +261,6 @@ struct intel_engine_cs {
>   
>   	intel_engine_mask_t mask;
>   
> -	u8 gen6_hw_id;
>   	u8 class;
>   	u8 instance;
>   
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 8750ffce9d61..d91386f4828e 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2572,7 +2572,9 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
>   #define   ARB_MODE_BWGTLB_DISABLE (1 << 9)
>   #define   ARB_MODE_SWIZZLE_BDW	(1 << 1)
>   #define RENDER_HWS_PGA_GEN7	_MMIO(0x04080)
> -#define RING_FAULT_REG(engine)	_MMIO(0x4094 + 0x100 * (engine)->gen6_hw_id)
> +
> +#define _GEN6_ENGINE_CLASS_TO_ID(class) _PICK((class), 0, 1, 3, 2)
> +#define RING_FAULT_REG(engine)	_MMIO(0x4094 + 0x100 * _GEN6_ENGINE_CLASS_TO_ID((engine)->class))

Makes sense to me.

Maybe HW_ID and HW_CLASS in the macro name? Not sure.

Only open I have is why the "Gen11+ HW Engine class + instance" comment 
and now we would tie that, allegedly Gen11 concept, with Gen6-7. Care to 
do some digging?

Regards,

Tvrtko

>   #define GEN8_RING_FAULT_REG	_MMIO(0x4094)
>   #define GEN12_RING_FAULT_REG	_MMIO(0xcec4)
>   #define   GEN8_RING_FAULT_ENGINE_ID(x)	(((x) >> 12) & 0x7)