From: "Eric R. Smith" <eric.smith@collabora.com>

MediaTek (MTK) uses some unique tiled memory formats
for video decoding. Add these to the uapi drm_fourcc.h
so that we can use them in Mesa, GStreamer, and other
tools/libraries.

Signed-off-by: Eric R. Smith <eric.smith@collabora.com>
---
 include/uapi/drm/drm_fourcc.h | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index 70f3b00b0681..22a27cdd6484 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -421,6 +421,7 @@ extern "C" {
 #define DRM_FORMAT_MOD_VENDOR_ARM     0x08
 #define DRM_FORMAT_MOD_VENDOR_ALLWINNER 0x09
 #define DRM_FORMAT_MOD_VENDOR_AMLOGIC 0x0a
+#define DRM_FORMAT_MOD_VENDOR_MTK     0x0b
 
 /* add more to the end as needed */
 
@@ -1453,6 +1454,36 @@ drm_fourcc_canonicalize_nvidia_format_mod(__u64 modifier)
  */
 #define AMLOGIC_FBC_OPTION_MEM_SAVING		(1ULL << 0)
 
+/* MediaTek layouts */
+
+/*
+ * MediaTek Tiled Modifier
+ * This is a tiled layout using tiles of 16x32 pixels in a row-major layout.
+ * For chroma planes this becomes 16x16 tiles.
+ */
+#define DRM_FORMAT_MOD_MTK_16L_32S_TILE  fourcc_mod_code(MTK, (1ULL << 0))
+
+/*
+ * MediaTek Compressed Modifier
+ * Indicates the planes are compressed.
+ * Implementation may be platform and base-format specific.
+ */
+#define DRM_FORMAT_MOD_MTK_COMPRESSED  fourcc_mod_code(MTK, (1ULL << 1))
+
+/*
+ * MediaTek 10-bit Modifier
+ * Indicates that the 2 LSBs of the 10 bit pixels are stored
+ * separately and tiled.
+ */
+#define DRM_FORMAT_MOD_MTK_LSBTILED    fourcc_mod_code(MTK, (1ULL << 2))
+
+/*
+ * MediaTek 10-bit Modifier
+ * Indicates that the 2 LSBs of 10 bit pixels are stored
+ * separately in raster order.
+ */
+#define DRM_FORMAT_MOD_MTK_LSBRASTER   fourcc_mod_code(MTK, (1ULL << 3))
+
 /*
  * AMD modifiers
  *

base-commit: 3a8e60188b55f7aff76c1d3707ebcbf98e68cc13
-- 
2.39.5

Hi Eric,

On Fri, 13 Dec 2024 at 18:47, <eric.smith@collabora.com> wrote:
> MediaTek (MTK) uses some unique tiled memory formats
> for video decoding. Add these to the uapi drm_fourcc.h
> so that we can use them in Mesa, GStreamer, and other
> tools/libraries.

Thanks for pushing these upstream!

> +/* MediaTek layouts */
> +
> +/*
> + * MediaTek Tiled Modifier
> + * This is a tiled layout using tiles of 16x32 pixels in a row-major layout.
> + * For chroma planes this becomes 16x16 tiles.
> + */
> +#define DRM_FORMAT_MOD_MTK_16L_32S_TILE  fourcc_mod_code(MTK, (1ULL << 0))

I think this probably wants to be something like the tiling mode
defined in AMD/Arm modifiers, i.e. reserve a few bits in the range to
select the tile size, rather than using a single bit here.

> +/*
> + * MediaTek Compressed Modifier
> + * Indicates the planes are compressed.
> + * Implementation may be platform and base-format specific.
> + */
> +#define DRM_FORMAT_MOD_MTK_COMPRESSED  fourcc_mod_code(MTK, (1ULL << 1))

Ditto for compression.

> +/*
> + * MediaTek 10-bit Modifier
> + * Indicates that the 2 LSBs of the 10 bit pixels are stored
> + * separately and tiled.
> + */
> +#define DRM_FORMAT_MOD_MTK_LSBTILED    fourcc_mod_code(MTK, (1ULL << 2))
> +
> +/*
> + * MediaTek 10-bit Modifier
> + * Indicates that the 2 LSBs of 10 bit pixels are stored
> + * separately in raster order.
> + */
> +#define DRM_FORMAT_MOD_MTK_LSBRASTER   fourcc_mod_code(MTK, (1ULL << 3))

Ditto for 10bpc packing.

So this would ultimately look something like:
mod = (DRM_FORMAT_MOD_MTK_TILE_SIZE(16L32S) |
DRM_FORMAT_MOD_MTK_COMPRESSION(V1) |
DRM_FORMAT_MOD_MTK_10BPC_PACK(RASTER))

Cheers,
Daniel

On 18/12/2024 10.33, Daniel Stone wrote:

>> +/* MediaTek layouts */
>> +
>> +/*
>> + * MediaTek Tiled Modifier
>> + * This is a tiled layout using tiles of 16x32 pixels in a row-major layout.
>> + * For chroma planes this becomes 16x16 tiles.
>> + */
>> +#define DRM_FORMAT_MOD_MTK_16L_32S_TILE  fourcc_mod_code(MTK, (1ULL << 0))
> I think this probably wants to be something like the tiling mode
> defined in AMD/Arm modifiers, i.e. reserve a few bits in the range to
> select the tile size, rather than using a single bit here.

Thank you for taking the time, and for your suggestions. Are you 
thinking something along the lines of:

/* MediaTek modifiers
  * Bits  Parameter                Notes
  * ----- ------------------------ 
---------------------------------------------
  *   3:0 TILE LAYOUT              Values are MTK_FMT_MOD_TILE_*
  *   7:4 COMPRESSION              Values are MTK_FMT_MOD_COMPRESS_*
  *  12:8 10 BIT LAYOUT            Values are MTK_FMT_MOD_10BIT_LAYOUT_*
  *
  */

#define DRM_FORMAT_MOD_MTK(__flags)        fourcc_mod_code(MTK, __flags)

/*
  * MediaTek Tiled Modifier
  * The lowest 4 bits of the modifier is used to specify the tiling
  * layout. Only the 16L_32S tiling is used for now, but we define an
  * "untiled" version and leave room for future expansion.
  */
#define MTK_FMT_MOD_TILE_MASK     0xf
#define MTK_FMT_MOD_TILE_NONE     0x0
#define MTK_FMT_MOD_TILE_16L32S   0x1

/*
  * Bits 4-7 specify compression options
  */
#define MTK_FMT_MOD_COMPRESS_MASK (0xf << 4)
#define MTK_FMT_MOD_COMPRESS_NONE (0x0 << 4)
#define MTK_FMT_MOD_COMPRESS_V1   (0x1 << 4)

/*
  * Bits 8-11 specify how the bits of 10 bit formats are
  * stored out in memory
  */
#define MTK_FMT_MOD_10BIT_LAYOUT_MASK      (0xf << 8)
#define MTK_FMT_MOD_10BIT_LAYOUT_PACKED    (0x0 << 8)
#define MTK_FMT_MOD_10BIT_LAYOUT_LSBTILED  (0x1 << 8)
#define MTK_FMT_MOD_10BIT_LAYOUT_LSBRASTER (0x2 << 8)

Regards,

Eric

Hey Eric,

On Thu, 19 Dec 2024 at 00:20, Eric Smith <eric.smith@collabora.com> wrote:
> On 18/12/2024 10.33, Daniel Stone wrote:
> >> +/*
> >> + * MediaTek Tiled Modifier
> >> + * This is a tiled layout using tiles of 16x32 pixels in a row-major layout.
> >> + * For chroma planes this becomes 16x16 tiles.
> >> + */
> >> +#define DRM_FORMAT_MOD_MTK_16L_32S_TILE  fourcc_mod_code(MTK, (1ULL << 0))
> > I think this probably wants to be something like the tiling mode
> > defined in AMD/Arm modifiers, i.e. reserve a few bits in the range to
> > select the tile size, rather than using a single bit here.
>
> Thank you for taking the time, and for your suggestions. Are you
> thinking something along the lines of:
>
> [...]

Yeah, that's exactly it. You could even push the boat out and widen
the fields a little bit to give more headroom; if you want to change
the layout because you want to add more flags or whatever, you can
just do what Arm did, and take the top couple of bits as a layout
version or epoch.

Cheers,
Daniel