On Tue, Sep 7, 2021 at 4:01 AM Christian König
<ckoenig.leichtzumerken@xxxxxxxxx> wrote:
>
> Briefly describe what this is all about.
>
> Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
> ---
> Documentation/gpu/drm-mm.rst | 3 +++
> include/drm/ttm/ttm_caching.h | 17 +++++++++++++++++
> 2 files changed, 20 insertions(+)
>
> diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst
> index 6b7717af4f88..f22c9f9a2c0e 100644
> --- a/Documentation/gpu/drm-mm.rst
> +++ b/Documentation/gpu/drm-mm.rst
> @@ -31,6 +31,9 @@ The Translation Table Manager (TTM)
> .. kernel-doc:: drivers/gpu/drm/ttm/ttm_module.c
> :doc: TTM
>
> +.. kernel-doc:: include/drm/ttm/ttm_caching.h
> + :internal:
> +
> The Graphics Execution Manager (GEM)
> ====================================
>
> diff --git a/include/drm/ttm/ttm_caching.h b/include/drm/ttm/ttm_caching.h
> index 3c9dd65f5aaf..235a743d90e1 100644
> --- a/include/drm/ttm/ttm_caching.h
> +++ b/include/drm/ttm/ttm_caching.h
> @@ -27,9 +27,26 @@
>
> #define TTM_NUM_CACHING_TYPES 3
>
> +/**
> + * enum ttm_caching - CPU caching and BUS snooping behavior.
> + */
> enum ttm_caching {
> + /**
> + * @ttm_uncached: Most defensive option for device mappings,
> + * don't even allow write combining.
> + */
> ttm_uncached,
> +
> + /**
> + * @ttm_write_combined: Don't cache read accesses, but allow at least
> + * writes to be combined.
> + */
> ttm_write_combined,
> +
> + /**
> + * @ttm_cached: Fully cached like normal system memory, requires that
> + * devices snoop the CPU cache on accesses.
> + */
> ttm_cached
> };
>
> --
> 2.25.1
>
