Re: [PATCH 2/6] drm/i915: Add macro for SSEU stride calculation

Daniele Ceraolo Spurio
2019-05-01T18:11:18Z

On 5/1/19 8:34 AM, Stuart Summers wrote:
> Subslice stride and EU stride are calculated multiple times in
> i915_query. Move this calculation to a macro to reduce code duplication.
>
> v2: update headers in intel_sseu.h
>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Signed-off-by: Stuart Summers <stuart.summers@intel.com>
> ---
> drivers/gpu/drm/i915/gt/intel_sseu.h | 2 ++
> drivers/gpu/drm/i915/i915_query.c | 17 ++++++++---------
> 2 files changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.h b/drivers/gpu/drm/i915/gt/intel_sseu.h
> index 73bc824094e8..c0b16b248d4c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_sseu.h
> +++ b/drivers/gpu/drm/i915/gt/intel_sseu.h
> @@ -8,11 +8,13 @@
> #define __INTEL_SSEU_H__
>
> #include <linux/types.h>
> +#include <linux/kernel.h>
>
> struct drm_i915_private;
>
> #define GEN_MAX_SLICES (6) /* CNL upper bound */
> #define GEN_MAX_SUBSLICES (8) /* ICL upper bound */
> +#define GEN_SSEU_STRIDE(bits) DIV_ROUND_UP(bits, BITS_PER_BYTE)

What we pass to this macro isn't really a bits count but the maximum
amount of s/ss/eus. s/bits/max_entry/, or something like that? with that:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

>
> struct sseu_dev_info {
> u8 slice_mask;
> diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> index 782183b78f49..7c1708c22811 100644
> --- a/drivers/gpu/drm/i915/i915_query.c
> +++ b/drivers/gpu/drm/i915/i915_query.c
> @@ -37,6 +37,8 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
> const struct sseu_dev_info *sseu = &RUNTIME_INFO(dev_priv)->sseu;
> struct drm_i915_query_topology_info topo;
> u32 slice_length, subslice_length, eu_length, total_length;
> + u8 subslice_stride = GEN_SSEU_STRIDE(sseu->max_subslices);
> + u8 eu_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
> int ret;
>
> if (query_item->flags != 0)
> @@ -48,12 +50,10 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
> BUILD_BUG_ON(sizeof(u8) != sizeof(sseu->slice_mask));
>
> slice_length = sizeof(sseu->slice_mask);
> - subslice_length = sseu->max_slices *
> - DIV_ROUND_UP(sseu->max_subslices, BITS_PER_BYTE);
> - eu_length = sseu->max_slices * sseu->max_subslices *
> - DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE);
> -
> - total_length = sizeof(topo) + slice_length + subslice_length + eu_length;
> + subslice_length = sseu->max_slices * subslice_stride;
> + eu_length = sseu->max_slices * sseu->max_subslices * eu_stride;
> + total_length = sizeof(topo) + slice_length + subslice_length +
> + eu_length;
>
> ret = copy_query_item(&topo, sizeof(topo), total_length,
> query_item);
> @@ -69,10 +69,9 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
> topo.max_eus_per_subslice = sseu->max_eus_per_subslice;
>
> topo.subslice_offset = slice_length;
> - topo.subslice_stride = DIV_ROUND_UP(sseu->max_subslices, BITS_PER_BYTE);
> + topo.subslice_stride = subslice_stride;
> topo.eu_offset = slice_length + subslice_length;
> - topo.eu_stride =
> - DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE);
> + topo.eu_stride = eu_stride;
>
> if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr),
> &topo, sizeof(topo)))