[Intel-gfx] [PATCH 05/11] drm/i915: Use local variables for subslice_mask for device info

[Chris Wilson]

Quoting Stuart Summers (2019-08-21 00:05:38)
> When setting up subslice_mask, instead of operating on the slice
> array directly, use a local variable to start bits per slice, then
> use this to set the per slice array in one step.
> 
> Signed-off-by: Stuart Summers <stuart.summers at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_device_info.c | 49 +++++++++++++-----------
>  1 file changed, 26 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
> index b1a79ed408eb..52515efe9f4e 100644
> --- a/drivers/gpu/drm/i915/intel_device_info.c
> +++ b/drivers/gpu/drm/i915/intel_device_info.c
> @@ -235,18 +235,6 @@ static void gen10_sseu_info_init(struct drm_i915_private *dev_priv)
>         sseu->slice_mask = (fuse2 & GEN10_F2_S_ENA_MASK) >>
>                             GEN10_F2_S_ENA_SHIFT;
>  
> -       subslice_mask = (1 << 4) - 1;
> -       subslice_mask &= ~((fuse2 & GEN10_F2_SS_DIS_MASK) >>
> -                          GEN10_F2_SS_DIS_SHIFT);
> -
> -       /*
> -        * Slice0 can have up to 3 subslices, but there are only 2 in
> -        * slice1/2.
> -        */
> -       sseu->subslice_mask[0] = subslice_mask;
> -       for (s = 1; s < sseu->max_slices; s++)
> -               sseu->subslice_mask[s] = subslice_mask & 0x3;
> -
>         /* Slice0 */
>         eu_en = ~I915_READ(GEN8_EU_DISABLE0);
>         for (ss = 0; ss < sseu->max_subslices; ss++)
> @@ -270,14 +258,24 @@ static void gen10_sseu_info_init(struct drm_i915_private *dev_priv)
>         eu_en = ~I915_READ(GEN10_EU_DISABLE3);
>         sseu_set_eus(sseu, 5, 1, eu_en & eu_mask);
>  
> -       /* Do a second pass where we mark the subslices disabled if all their
> -        * eus are off.
> -        */
> +       subslice_mask = (1 << 4) - 1;
> +       subslice_mask &= ~((fuse2 & GEN10_F2_SS_DIS_MASK) >>
> +                          GEN10_F2_SS_DIS_SHIFT);
> +
>         for (s = 0; s < sseu->max_slices; s++) {
> +               u32 subslice_mask_with_eus = subslice_mask;
> +
>                 for (ss = 0; ss < sseu->max_subslices; ss++) {
>                         if (sseu_get_eus(sseu, s, ss) == 0)
> -                               sseu->subslice_mask[s] &= ~BIT(ss);
> +                               subslice_mask_with_eus &= ~BIT(ss);
>                 }
> +
> +               /*
> +                * Slice0 can have up to 3 subslices, but there are only 2 in
> +                * slice1/2.
> +                */
> +               sseu->subslice_mask[s] = s == 0 ? subslice_mask_with_eus :
> +                                                 subslice_mask_with_eus & 0x3;

Ok. I have no idea what the topology is or why, but I followed the code
and it should not be any logic changes.

>         }
>  
>         sseu->eu_total = compute_eu_total(sseu);
> @@ -303,6 +301,7 @@ static void cherryview_sseu_info_init(struct drm_i915_private *dev_priv)
>  {
>         struct sseu_dev_info *sseu = &RUNTIME_INFO(dev_priv)->sseu;
>         u32 fuse;
> +       u8 subslice_mask = 0;
>  
>         fuse = I915_READ(CHV_FUSE_GT);
>  
> @@ -316,7 +315,7 @@ static void cherryview_sseu_info_init(struct drm_i915_private *dev_priv)
>                         (((fuse & CHV_FGT_EU_DIS_SS0_R1_MASK) >>
>                           CHV_FGT_EU_DIS_SS0_R1_SHIFT) << 4);
>  
> -               sseu->subslice_mask[0] |= BIT(0);
> +               subslice_mask |= BIT(0);
>                 sseu_set_eus(sseu, 0, 0, ~disabled_mask);
>         }
>  
> @@ -327,10 +326,12 @@ static void cherryview_sseu_info_init(struct drm_i915_private *dev_priv)
>                         (((fuse & CHV_FGT_EU_DIS_SS1_R1_MASK) >>
>                           CHV_FGT_EU_DIS_SS1_R1_SHIFT) << 4);
>  
> -               sseu->subslice_mask[0] |= BIT(1);
> +               subslice_mask |= BIT(1);
>                 sseu_set_eus(sseu, 0, 1, ~disabled_mask);
>         }
>  
> +       sseu->subslice_mask[0] = subslice_mask;
> +
>         sseu->eu_total = compute_eu_total(sseu);

Ok.

>  
>         /*
> @@ -540,6 +541,7 @@ static void haswell_sseu_info_init(struct drm_i915_private *dev_priv)
>  {
>         struct sseu_dev_info *sseu = &RUNTIME_INFO(dev_priv)->sseu;
>         u32 fuse1;
> +       u8 subslice_mask = 0;
>         int s, ss;
>  
>         /*
> @@ -552,16 +554,15 @@ static void haswell_sseu_info_init(struct drm_i915_private *dev_priv)
>                 /* fall through */
>         case 1:
>                 sseu->slice_mask = BIT(0);
> -               sseu->subslice_mask[0] = BIT(0);
> +               subslice_mask = BIT(0);
>                 break;
>         case 2:
>                 sseu->slice_mask = BIT(0);
> -               sseu->subslice_mask[0] = BIT(0) | BIT(1);
> +               subslice_mask = BIT(0) | BIT(1);
>                 break;
>         case 3:
>                 sseu->slice_mask = BIT(0) | BIT(1);
> -               sseu->subslice_mask[0] = BIT(0) | BIT(1);
> -               sseu->subslice_mask[1] = BIT(0) | BIT(1);
> +               subslice_mask = BIT(0) | BIT(1);
>                 break;
>         }
>  
> @@ -583,10 +584,12 @@ static void haswell_sseu_info_init(struct drm_i915_private *dev_priv)
>         }
>  
>         intel_sseu_set_info(sseu, hweight8(sseu->slice_mask),
> -                           hweight8(sseu->subslice_mask[0]),
> +                           hweight8(subslice_mask),
>                             sseu->eu_per_subslice);
>  
>         for (s = 0; s < sseu->max_slices; s++) {
> +               sseu->subslice_mask[s] = subslice_mask;
> +
>                 for (ss = 0; ss < sseu->max_subslices; ss++) {
>                         sseu_set_eus(sseu, s, ss,
>                                      (1UL << sseu->eu_per_subslice) - 1);

Ok.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris