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Subject: Re: [PATCH v2 1/5] v4l: Add Qualcomm custom compressed pixel formats
From:   Hans Verkuil <hverkuil-cisco@xs4all.nl>
To:     Stanimir Varbanov <stanimir.varbanov@linaro.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, linux-api@vger.kernel.org
References: <20210706124034.773503-1-stanimir.varbanov@linaro.org>
 <20210706124034.773503-2-stanimir.varbanov@linaro.org>
 <d7d9cfe3-86b6-f17c-7742-e0965c8b9899@xs4all.nl>
Message-ID: <e0b26ee1-3109-06fe-5283-ac978fc768de@xs4all.nl>
Date:   Wed, 28 Jul 2021 12:10:35 +0200
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On 28/07/2021 12:09, Hans Verkuil wrote:
> On 06/07/2021 14:40, Stanimir Varbanov wrote:
>> Add custom Qualcomm raw compressed pixel formats. They are
>> used in Qualcomm SoCs to optimize the interconnect bandwidth.
>>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
>> ---
>>  .../media/v4l/pixfmt-reserved.rst              | 18 ++++++++++++++++++
>>  drivers/media/v4l2-core/v4l2-ioctl.c           |  2 ++
>>  include/uapi/linux/videodev2.h                 |  2 ++
>>  3 files changed, 22 insertions(+)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>> index 0b879c0da713..136e9832db0c 100644
>> --- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>> @@ -260,6 +260,24 @@ 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-QC08C:
>> +
>> +      - ``V4L2_PIX_FMT_QC08C``
>> +      - 'QC08C'
>> +      - Compressed Macro-tile 8-Bit YUV420 format used by Qualcomm platforms.
>> +	The used compression is lossless and it is used by various multimedia
>> +	hardware blocks like GPU, display controllers, ISP and video accelerators.
>> +	It contains four planes for progressive video and eight planes for
>> +	interlaced video.
>> +    * .. _V4L2-PIX-FMT-QC10C:
>> +
>> +      - ``V4L2_PIX_FMT_QC10C``
>> +      - 'QC10C'
>> +      - Compressed Macro-tile 10-Bit YUV420 format used by Qualcomm platforms.
>> +	The used compression is lossless and it is used by various multimedia
>> +	hardware blocks like GPU, display controllers, ISP and video.
>> +	It contains four planes for progressive video and eight planes for
>> +	interlaced video.
> 
> These two formats are opaque formats? Or is it something that userspace can
> decode as well with the help of a datasheet or something similar?
> 
> If it is opaque (as I expect it is), then please add the phrase:
> 'It is an opaque intermediate format.'

If it is not an opaque format, then add a reference to QCom documentation that
describes it (even if it is only available under NDA).

Regards,

	Hans

> 
> Regards,
> 
> 	Hans
> 
>>  
>>  .. raw:: latex
>>  
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 05d5db3d85e5..76d4e4ac18e8 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -1416,6 +1416,8 @@ 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_QC08C:	descr = "QCOM Compressed 8-bit Format"; break;
>> +		case V4L2_PIX_FMT_QC10C:	descr = "QCOM Compressed 10-bit Format"; break;
>>  		default:
>>  			if (fmt->description[0])
>>  				return;
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 9260791b8438..dc1b714ccf6b 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -737,6 +737,8 @@ struct v4l2_pix_format {
>>  #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_HI240    v4l2_fourcc('H', 'I', '2', '4') /* BTTV 8-bit dithered RGB */
>> +#define V4L2_PIX_FMT_QC08C    v4l2_fourcc('Q', '0', '8', 'C') /* Qualcomm 8-bit compressed */
>> +#define V4L2_PIX_FMT_QC10C    v4l2_fourcc('Q', '1', '0', 'C') /* Qualcomm 10-bit compressed */
>>  
>>  /* 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 */
>>
>