Re: [PATCH v3 1/2] drm/xe/guc: Add support for w/a KLVs

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 25.03.2024 16:04, Badal Nilawar wrote:
> To prevent running out of bits, new w/a enable flags are being added

nit: shouldn't we spell out "workaround" or use "W/A" as acronym ?

> via a KLV system instead of a 32 bit flags word.
> 
> v2: GuC version check > 70.10 is not needed as xe will not be supporting
>     anything below < 70.19 (John Harrison)
> v3: Use 64 bit ggtt address for future
>     compatibility (John Harrison/Daniele)
> 
> Cc: John Harrison <John.C.Harrison@intel.com>
> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_guc_ads.c       | 62 ++++++++++++++++++++++++++-
>  drivers/gpu/drm/xe/xe_guc_ads_types.h |  2 +
>  drivers/gpu/drm/xe/xe_guc_fwif.h      |  5 ++-
>  3 files changed, 66 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_ads.c b/drivers/gpu/drm/xe/xe_guc_ads.c
> index df2bffb7e220..a98344a0ff4b 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ads.c
> +++ b/drivers/gpu/drm/xe/xe_guc_ads.c
> @@ -80,6 +80,10 @@ ads_to_map(struct xe_guc_ads *ads)
>   *      +---------------------------------------+
>   *      | padding                               |
>   *      +---------------------------------------+ <== 4K aligned
> + *      | w/a KLVs                              |
> + *      +---------------------------------------+
> + *      | padding                               |
> + *      +---------------------------------------+ <== 4K aligned
>   *      | capture lists                         |
>   *      +---------------------------------------+
>   *      | padding                               |
> @@ -131,6 +135,11 @@ static size_t guc_ads_golden_lrc_size(struct xe_guc_ads *ads)
>  	return PAGE_ALIGN(ads->golden_lrc_size);
>  }
>  
> +static u32 guc_ads_waklv_size(struct xe_guc_ads *ads)
> +{
> +	return PAGE_ALIGN(ads->ads_waklv_size);

btw, shouldn't we start using ALIGN(xx, SZ_4K)

> +}
> +
>  static size_t guc_ads_capture_size(struct xe_guc_ads *ads)
>  {
>  	/* FIXME: Allocate a proper capture list */
> @@ -167,12 +176,22 @@ static size_t guc_ads_golden_lrc_offset(struct xe_guc_ads *ads)
>  	return PAGE_ALIGN(offset);
>  }
>  
> +static size_t guc_ads_waklv_offset(struct xe_guc_ads *ads)
> +{
> +	u32 offset;
> +
> +	offset = guc_ads_golden_lrc_offset(ads) +
> +		 guc_ads_golden_lrc_size(ads);
> +
> +	return PAGE_ALIGN(offset);
> +}
> +
>  static size_t guc_ads_capture_offset(struct xe_guc_ads *ads)
>  {
>  	size_t offset;
>  
> -	offset = guc_ads_golden_lrc_offset(ads) +
> -		guc_ads_golden_lrc_size(ads);
> +	offset = guc_ads_waklv_offset(ads) +
> +		 guc_ads_waklv_size(ads);
>  
>  	return PAGE_ALIGN(offset);
>  }
> @@ -260,6 +279,42 @@ static size_t calculate_golden_lrc_size(struct xe_guc_ads *ads)
>  	return total_size;
>  }
>  
> +static void guc_waklv_init(struct xe_guc_ads *ads)
> +{
> +	u64 addr_ggtt;
> +	u32 offset, remain, size;
> +
> +	offset = guc_ads_waklv_offset(ads);
> +	remain = guc_ads_waklv_size(ads);
> +
> +	/*
> +	 * Add workarounds here:
> +	 *
> +	 * if (want_wa_<name>) {
> +	 *      size = guc_waklv_<name>(guc, offset, remain);
> +	 *      offset += size;
> +	 *      remain -= size;

maybe just asserting the used size will work ?

		used += guc_waklv_NAME(guc, offset + used);
		xe_gt_assert(gt, used <= guc_ads_waklv_size(ads));

> +	 * }
> +	 */
> +
> +	size = guc_ads_waklv_size(ads) - remain;
> +	if (!size)
> +		return;
> +
> +	offset = guc_ads_waklv_offset(ads);
> +	addr_ggtt = xe_bo_ggtt_addr(ads->bo) + offset;
> +
> +	ads_blob_write(ads, ads.wa_klv_addr_lo, lower_32_bits(addr_ggtt));
> +	ads_blob_write(ads, ads.wa_klv_addr_hi, upper_32_bits(addr_ggtt));
> +	ads_blob_write(ads, ads.wa_klv_size, size);
> +}
> +
> +static int calculate_waklv_size(struct xe_guc_ads *ads)
> +{
> +	/* Fudge something chunky for now: */
> +	return PAGE_SIZE;

maybe SZ_4K ?

and is it really a 'calculate' helper ?

if so then maybe add template comment how this will be calculated using
want_wa_<name> and guc_waklv_<name> tuples

> +}
> +
>  #define MAX_GOLDEN_LRC_SIZE	(SZ_4K * 64)
>  
>  int xe_guc_ads_init(struct xe_guc_ads *ads)
> @@ -271,6 +326,7 @@ int xe_guc_ads_init(struct xe_guc_ads *ads)
>  
>  	ads->golden_lrc_size = calculate_golden_lrc_size(ads);
>  	ads->regset_size = calculate_regset_size(gt);
> +	ads->ads_waklv_size = calculate_waklv_size(ads);
>  
>  	bo = xe_managed_bo_create_pin_map(xe, tile, guc_ads_size(ads) + MAX_GOLDEN_LRC_SIZE,
>  					  XE_BO_CREATE_SYSTEM_BIT |
> @@ -598,6 +654,8 @@ void xe_guc_ads_populate(struct xe_guc_ads *ads)
>  	guc_mapping_table_init(gt, &info_map);
>  	guc_capture_list_init(ads);
>  	guc_doorbell_init(ads);
> +	/* Workaround KLV list */

drop useless comment ...

> +	guc_waklv_init(ads);
>  
>  	if (xe->info.has_usm) {
>  		guc_um_init_params(ads);
> diff --git a/drivers/gpu/drm/xe/xe_guc_ads_types.h b/drivers/gpu/drm/xe/xe_guc_ads_types.h
> index 4afe44bece4b..62235b2a6fe3 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ads_types.h
> +++ b/drivers/gpu/drm/xe/xe_guc_ads_types.h
> @@ -20,6 +20,8 @@ struct xe_guc_ads {
>  	size_t golden_lrc_size;
>  	/** @regset_size: size of register set passed to GuC for save/restore */
>  	u32 regset_size;
> +	/** @ads_waklv_size: waklv size */

... instead improve comment here

> +	u32 ads_waklv_size;
>  };
>  
>  #endif
> diff --git a/drivers/gpu/drm/xe/xe_guc_fwif.h b/drivers/gpu/drm/xe/xe_guc_fwif.h
> index c281fdbfd2d6..52503719d2aa 100644
> --- a/drivers/gpu/drm/xe/xe_guc_fwif.h
> +++ b/drivers/gpu/drm/xe/xe_guc_fwif.h
> @@ -207,7 +207,10 @@ struct guc_ads {
>  	u32 capture_instance[GUC_CAPTURE_LIST_INDEX_MAX][GUC_MAX_ENGINE_CLASSES];
>  	u32 capture_class[GUC_CAPTURE_LIST_INDEX_MAX][GUC_MAX_ENGINE_CLASSES];
>  	u32 capture_global[GUC_CAPTURE_LIST_INDEX_MAX];
> -	u32 reserved[14];
> +	u32 wa_klv_addr_lo;
> +	u32 wa_klv_addr_hi;
> +	u32 wa_klv_size;

maybe it's worth to add a comment from which GuC version these new
fields are redefined

> +	u32 reserved[11];
>  } __packed;
>  
>  /* Engine usage stats */