[PATCH v8 1/4] media: v4l: Add definition for the Aspeed JPEG format

[Jammy Huang]

Hi Hans,

On 2022/1/14 下午 04:11, Hans Verkuil wrote:
> On 24/12/2021 02:27, Jammy Huang wrote:
>> This introduces support for the Aspeed JPEG format, where the new frame
>> can refer to previous frame to reduce the amount of compressed data. The
>> concept is similar to I/P frame of video compression. It will compare the
>> new frame with previous one to decide which macroblock's data is
>> changed, and only the changed macroblocks will be compressed.
>>
>> This Aspeed JPEG format is used by the video engine on Aspeed platforms,
>> which is generally adapted for remote KVM.
>>
>> Signed-off-by: Jammy Huang <jammy_huang at aspeedtech.com>
>> ---
>> v8:
>>    - Add decoder information for aspeed-jpeg
>> v7:
>>    - Add more information for aspeed-jpeg
>> v6:
>>    - Update description for new format, aspeed-jpeg, in Documentation.
>> v5:
>>    - no update
>> v4:
>>    - new
>> ---
>>   .../media/uapi/v4l/pixfmt-reserved.rst          | 17 +++++++++++++++++
>>   drivers/media/v4l2-core/v4l2-ioctl.c            |  1 +
>>   include/uapi/linux/videodev2.h                  |  1 +
>>   3 files changed, 19 insertions(+)
>>
>> diff --git a/Documentation/media/uapi/v4l/pixfmt-reserved.rst b/Documentation/media/uapi/v4l/pixfmt-reserved.rst
> This is the wrong file! It should be:
>
> Documentation/userspace-api/media/v4l/pixfmt-reserved.rst

Thanks, I just used git format-patch to generate the cover-letter and 
didn't notice this.

It looks like the file, pixfmt-reserved.rst, has different path in 
different Linux kernel,

* 5.4:           Documentation/media/uapi/v4l/pixfmt-reserved.rst

* 5.10/5.15: Documentation/userspace-api/media/v4l/pixfmt-reserved.rst

5.4 is the one I based to submit the patches.

Could you suggest the kernel that I should based to submit these patches??

I will need to change the number of V4L2_CID_USER_ASPEED_BASE per different

linux kernel as well.

>
> Regards,
>
> 	Hans
>
>> index b2cd155e691b..1d0dc8d86ed7 100644
>> --- a/Documentation/media/uapi/v4l/pixfmt-reserved.rst
>> +++ b/Documentation/media/uapi/v4l/pixfmt-reserved.rst
>> @@ -264,6 +264,23 @@ please make a proposal on the linux-media mailing list.
>>   	of tiles, resulting in 32-aligned resolutions for the luminance plane
>>   	and 16-aligned resolutions for the chrominance plane (with 2x2
>>   	subsampling).
>> +    * .. _V4L2-PIX-FMT-AJPG:
>> +
>> +      - ``V4L2_PIX_FMT_AJPG``
>> +      - 'AJPG'
>> +      - ASPEED JPEG format used by the aspeed-video driver on Aspeed platforms,
>> +        which is generally adapted for remote KVM.
>> +        On each frame compression, I will compare the new frame with previous
>> +        one to decide which macroblock's data is changed, and only the changed
>> +        macroblocks will be compressed.
>> +
>> +        The implementation is based on AST2600 A3 datasheet, revision 0.9, which
>> +        is not publicly available. Or you can reference Video stream data format
>> +        – ASPEED mode compression of SDK_User_Guide which available on
>> +        AspeedTech-BMC/openbmc/releases.
>> +
>> +        Decoder's implementation can be found here,
>> +        `https://github.com/AspeedTech-BMC/aspeed_codec/ <https://github.com/AspeedTech-BMC/aspeed_codec/>`__
>>   
>>   .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
>>   
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 24db33f803c0..00dde01d2f97 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -1378,6 +1378,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>>   		case V4L2_PIX_FMT_S5C_UYVY_JPG:	descr = "S5C73MX interleaved UYVY/JPEG"; break;
>>   		case V4L2_PIX_FMT_MT21C:	descr = "Mediatek Compressed Format"; break;
>>   		case V4L2_PIX_FMT_SUNXI_TILED_NV12: descr = "Sunxi Tiled NV12 Format"; break;
>> +		case V4L2_PIX_FMT_AJPG:		descr = "Aspeed JPEG"; break;
>>   		default:
>>   			if (fmt->description[0])
>>   				return;
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 3210b3c82a4a..994eb6155ea9 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -726,6 +726,7 @@ struct v4l2_pix_format {
>>   #define V4L2_PIX_FMT_INZI     v4l2_fourcc('I', 'N', 'Z', 'I') /* Intel Planar Greyscale 10-bit and Depth 16-bit */
>>   #define V4L2_PIX_FMT_SUNXI_TILED_NV12 v4l2_fourcc('S', 'T', '1', '2') /* Sunxi Tiled NV12 Format */
>>   #define V4L2_PIX_FMT_CNF4     v4l2_fourcc('C', 'N', 'F', '4') /* Intel 4-bit packed depth confidence information */
>> +#define V4L2_PIX_FMT_AJPG     v4l2_fourcc('A', 'J', 'P', 'G') /* Aspeed JPEG */
>>   
>>   /* 10bit raw bayer packed, 32 bytes for every 25 pixels, last LSB 6 bits unused */
>>   #define V4L2_PIX_FMT_IPU3_SBGGR10	v4l2_fourcc('i', 'p', '3', 'b') /* IPU3 packed 10-bit BGGR bayer */

-- 
Best Regards
Jammy