[PATCH v4 1/5] drm/xe/topology: Add a function to find the index of the last DSS in a mask

[Matt Roper]

On Sun, Oct 13, 2024 at 11:00:32PM -0700, Harish Chegondi wrote:
> Signed-off-by: Harish Chegondi <harish.chegondi at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_topology.c | 9 +++++++++
>  drivers/gpu/drm/xe/xe_gt_topology.h | 3 +++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_topology.c b/drivers/gpu/drm/xe/xe_gt_topology.c
> index df2042db7ee6..1e7476f71906 100644
> --- a/drivers/gpu/drm/xe/xe_gt_topology.c
> +++ b/drivers/gpu/drm/xe/xe_gt_topology.c
> @@ -278,6 +278,15 @@ xe_dss_mask_group_ffs(const xe_dss_mask_t mask, int groupsize, int groupnum)
>  	return find_next_bit(mask, XE_MAX_DSS_FUSE_BITS, groupnum * groupsize);
>  }
>  
> +/*
> + * Used to obtain the index of the last DSS.
> + */

We should probably have a true kerneldoc comment here.  And indicate
what happens if the mask is empty, since it isn't obvious without
looking at the implementation here.

> +unsigned int
> +xe_dss_mask_last_dss(const xe_dss_mask_t mask)

We're not 100% successful, but usually we try to prefix non-static
functions with the same name as the file they're defined in.  So this
would be better as something along the lines of
xe_gt_topology_mask_last_dss .

> +{
> +	return find_last_bit(mask, XE_MAX_DSS_FUSE_BITS);

Since this is just a 1-liner, it might be fine to just put it in the
header file as a static inline.


Matt

> +}
> +
>  bool xe_dss_mask_empty(const xe_dss_mask_t mask)
>  {
>  	return bitmap_empty(mask, XE_MAX_DSS_FUSE_BITS);
> diff --git a/drivers/gpu/drm/xe/xe_gt_topology.h b/drivers/gpu/drm/xe/xe_gt_topology.h
> index 746b325bbf6e..7ee022784397 100644
> --- a/drivers/gpu/drm/xe/xe_gt_topology.h
> +++ b/drivers/gpu/drm/xe/xe_gt_topology.h
> @@ -28,6 +28,9 @@ void xe_gt_topology_dump(struct xe_gt *gt, struct drm_printer *p);
>  unsigned int
>  xe_dss_mask_group_ffs(const xe_dss_mask_t mask, int groupsize, int groupnum);
>  
> +unsigned int
> +xe_dss_mask_last_dss(const xe_dss_mask_t mask);
> +
>  bool xe_dss_mask_empty(const xe_dss_mask_t mask);
>  
>  bool
> -- 
> 2.45.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation