Re: [PATCH v2] drm/fourcc: Add Arm 16x16 block modifier

[Qiang Yu]

Hi Ayan,

Thanks for the patch. I'm OK with either the static reserved type way or
the previous dynamic way. So this patch is:
Reviewed-by: Qiang Yu <yuq825@xxxxxxxxx>

PS. for anyone would like to know the usage of this modifier, lima mesa
driver need this modifier to denote some tiled texture format and shared
between client and display server.

Regards,
Qiang

On Tue, Oct 1, 2019 at 12:45 AM Ayan Halder <Ayan.Halder@xxxxxxx> wrote:
>
> Add the DRM_FORMAT_MOD_ARM_16X16_BLOCK_U_INTERLEAVED modifier to
> denote the 16x16 block u-interleaved format used in Arm Utgard and
> Midgard GPUs.
>
> Changes from v1:-
> 1. Reserved the upper four bits (out of the 56 bits assigned to each vendor)
> to denote the category of Arm specific modifiers. Currently, we have two
> categories ie AFBC and MISC.
>
> Signed-off-by: Raymond Smith <raymond.smith@xxxxxxx>
> Signed-off-by: Ayan kumar halder <ayan.halder@xxxxxxx>
> ---
>  include/uapi/drm/drm_fourcc.h | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index 3feeaa3f987a..b1d3de961109 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -648,7 +648,21 @@ extern "C" {
>   * Further information on the use of AFBC modifiers can be found in
>   * Documentation/gpu/afbc.rst
>   */
> -#define DRM_FORMAT_MOD_ARM_AFBC(__afbc_mode)   fourcc_mod_code(ARM, __afbc_mode)
> +
> +/*
> + * The top 4 bits (out of the 56 bits alloted for specifying vendor specific
> + * modifiers) denote the category for modifiers. Currently we have only two
> + * categories of modifiers ie AFBC and MISC. We can have a maximum of sixteen
> + * different categories.
> + */
> +#define DRM_FORMAT_MOD_ARM_CODE(type, val) \
> +       fourcc_mod_code(ARM, ((__u64)type << 52) | ((val) & 0x000fffffffffffffULL))
> +
> +#define DRM_FORMAT_MOD_ARM_TYPE_AFBC 0x00
> +#define DRM_FORMAT_MOD_ARM_TYPE_MISC 0x01
> +
> +#define DRM_FORMAT_MOD_ARM_AFBC(__afbc_mode) \
> +       DRM_FORMAT_MOD_ARM_CODE(DRM_FORMAT_MOD_ARM_TYPE_AFBC, __afbc_mode)
>
>  /*
>   * AFBC superblock size
> @@ -742,6 +756,17 @@ extern "C" {
>   */
>  #define AFBC_FORMAT_MOD_BCH     (1ULL << 11)
>
> +/*
> + * Arm 16x16 Block U-Interleaved modifier
> + *
> + * This is used by Arm Mali Utgard and Midgard GPUs. It divides the image
> + * into 16x16 pixel blocks. Blocks are stored linearly in order, but pixels
> + * in the block are reordered.
> + */
> +#define DRM_FORMAT_MOD_ARM_16X16_BLOCK_U_INTERLEAVED \
> +       DRM_FORMAT_MOD_ARM_CODE(DRM_FORMAT_MOD_ARM_TYPE_MISC, 1ULL)
> +
> +
>  /*
>   * Allwinner tiled modifier
>   *
> --
> 2.23.0
>