Re: [PATCH v6,14/24] media: mediatek: vcodec: Add capture format to support one plane memory

[Andrzej Pietrasiewicz <andrzej.p@collabora.com>]

Hi,

I'm having second thoughts, please see inline,

W dniu 22.05.2024 o 14:26, Andrzej Pietrasiewicz pisze:
> Hi Yunfei,
> 
> W dniu 16.05.2024 o 14:20, Yunfei Dong pisze:
>> Define one uncompressed capture format V4L2_PIX_FMT_MS21 in order to
>> support one plane memory. The buffer size is luma + chroma, luma is
>> stored at the start and chrome is stored at the end.
>>
>> Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
>> ---
>>   Documentation/userspace-api/media/v4l/pixfmt-reserved.rst | 8 ++++++++
>>   drivers/media/v4l2-core/v4l2-common.c                     | 2 ++
>>   drivers/media/v4l2-core/v4l2-ioctl.c                      | 1 +
>>   include/uapi/linux/videodev2.h                            | 1 +
>>   4 files changed, 12 insertions(+)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>> index 886ba7b08d6b..6ec899649d50 100644
>> --- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>> @@ -295,6 +295,14 @@ please make a proposal on the linux-media mailing list.
>>         - Compressed format used by Nuvoton NPCM video driver. This format is
>>           defined in Remote Framebuffer Protocol (RFC 6143, chapter 7.7.4 Hextile
>>           Encoding).
>> +    * .. _V4L2-PIX-FMT-MS21:
>> +
>> +      - ``V4L2_PIX_FMT_MS21``
>> +      - 'MS21'
>> +      - This format has one plane, luma and chroma are stored in a contiguous
> 
> Maybe s/one/single ?
> 
>> +        memory. Luma pixel in 16x32 tiles at the start, chroma pixel in 16x16
> 
> maybe the word "pixel" is reduntant here? What else than pixels could tile sizes mean?
> Any padding between luma and chroma?
> 
>> +        tiles at the end. The image height must be aligned with 32 and the image
>> +        width must be aligned with 16.
> 
> Maybe aligned to?
> 
>>   .. raw:: latex
>>       \normalsize
>> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
>> index 4165c815faef..5ae54cf48dc7 100644
>> --- a/drivers/media/v4l2-core/v4l2-common.c
>> +++ b/drivers/media/v4l2-core/v4l2-common.c
>> @@ -271,6 +271,8 @@ const struct v4l2_format_info *v4l2_format_info(u32 format)
>>             .block_w = { 16, 8, 0, 0 }, .block_h = { 32, 16, 0, 0 }},
>>           { .format = V4L2_PIX_FMT_MT2110R, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 2, .comp_planes = 2, .bpp = { 5, 10, 0, 0 }, .bpp_div = { 4, 4, 1, 1 }, .hdiv = 2, .vdiv = 2,
>>             .block_w = { 16, 8, 0, 0 }, .block_h = { 32, 16, 0, 0 }},
>> +        { .format = V4L2_PIX_FMT_MS21, pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .bpp_div = { 1, 1, 1, 1 }, .hdiv = 2, .vdiv = 2,
>> +          .block_w = { 16, 8, 0, 0 }, .block_h = { 32, 16, 0, 0 }},
>>           /* YUV planar formats */
>>           { .format = V4L2_PIX_FMT_NV12,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .bpp_div = { 1, 1, 1, 1 }, .hdiv = 2, .vdiv = 2 },
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 4c76d17b4629..3a68f2b9e7a4 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -1529,6 +1529,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>>           case V4L2_PIX_FMT_MT2110T:    descr = "Mediatek 10bit Tile Mode"; break;
>>           case V4L2_PIX_FMT_MT2110R:    descr = "Mediatek 10bit Raster Mode"; break;
>>           case V4L2_PIX_FMT_HEXTILE:    descr = "Hextile Compressed Format"; break;
>> +        case V4L2_PIX_FMT_MS21:        descr = "MediaTek One Plane Format"; break;
> 
> s/One/Single ?
> 

On the other hand "single" would be [in this case incorrectly] associated with
single-planar API, which would be totally confusing.

Still, the reality you are trying to model is complex: you use
MPLANE, yet there's a single plane in case of secure playback.

Regards,

Andrzej


> Regards,
> 
> Andrzej
> 
>>           default:
>>               if (fmt->description[0])
>>                   return;
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 89eb1a3c6555..7aff2f2c8f9c 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -800,6 +800,7 @@ struct v4l2_pix_format {
>>   #define V4L2_PIX_FMT_MM21     v4l2_fourcc('M', 'M', '2', '1') /* Mediatek 8-bit block mode, two non-contiguous planes */
>>   #define V4L2_PIX_FMT_MT2110T  v4l2_fourcc('M', 'T', '2', 'T') /* Mediatek 10-bit block tile mode */
>>   #define V4L2_PIX_FMT_MT2110R  v4l2_fourcc('M', 'T', '2', 'R') /* Mediatek 10-bit block raster mode */
>> +#define V4L2_PIX_FMT_MS21     v4l2_fourcc('M', 'S', '2', '1') /* MediaTek 8-bit block mode with one plane */
>>   #define V4L2_PIX_FMT_INZI     v4l2_fourcc('I', 'N', 'Z', 'I') /* Intel Planar Greyscale 10-bit and Depth 16-bit */
>>   #define V4L2_PIX_FMT_CNF4     v4l2_fourcc('C', 'N', 'F', '4') /* Intel 4-bit packed depth confidence information */
>>   #define V4L2_PIX_FMT_HI240    v4l2_fourcc('H', 'I', '2', '4') /* BTTV 8-bit dithered RGB */
>