[libcamera-devel] [PATCH v2 3/7] include: drm_fourcc: Add Bayer FourCC and modifiers

[Jacopo Mondi]

Hi Niklas,

On Thu, Mar 26, 2020 at 11:58:40PM +0100, Niklas Söderlund wrote:
> Add Bayer format and modifiers for patch submitted for upstream
> inclusion. The formats have not been accepted upstream yet but is needed
> to progress with RAW capture support in libcamera.
>
> Intention is to merge this in libcamera and update the header file the
> upstream patch is picked up upstream.
>

Just wondering if this needs a notice somewhere that this is a
temporary version.

With or without this
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Thanks
   j
> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
> * Changes since v1
> - Removed DNI label
> ---
>  include/linux/drm_fourcc.h | 94 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 94 insertions(+)
>
> diff --git a/include/linux/drm_fourcc.h b/include/linux/drm_fourcc.h
> index 4bb1bfe93d5f4390..69240dfe1df0df28 100644
> --- a/include/linux/drm_fourcc.h
> +++ b/include/linux/drm_fourcc.h
> @@ -288,6 +288,62 @@ extern "C" {
>  /* Compressed formats */
>  #define DRM_FORMAT_MJPEG	fourcc_code('M', 'J', 'P', 'G') /* Motion-JPEG */
>
> +/*
> + * Bayer formats
> + *
> + * Bayer formats contain green, red and blue components, with alternating lines
> + * of red and green, and blue and green pixels in different orders. For each
> + * block of 2x2 pixels there is one pixel with a red filter, two with a green
> + * filter, and one with a blue filter. The filters can be arranged in different
> + * patterns.
> + *
> + * For example, RGGB:
> + *	row0: RGRGRGRG...
> + *	row1: GBGBGBGB...
> + *	row3: RGRGRGRG...
> + *	row4: GBGBGBGB...
> + *	...
> + *
> + * Vendors have different methods to pack the sampling formats to increase data
> + * density. For this reason the fourcc only describes pixel sample size and the
> + * filter pattern for each block of 2x2 pixels. A modifier is needed to
> + * describe the memory layout.
> + *
> + * In addition to vendor modifiers for memory layout DRM_FORMAT_MOD_LINEAR may
> + * be used to describe a layout where all samples are placed consecutively in
> + * memory. If the sample does not fit inside a single byte, the sample storage
> + * is extended to the minimum number of (little endian) bytes that can hold the
> + * sample and any unused most-significant bits are defined as padding.
> + *
> + * For example, SRGGB10:
> + * Each 10-bit sample is contained in 2 consecutive little endian bytes, where
> + * the 6 most-significant bits are unused.
> + */
> +
> +/* 8-bit Bayer formats */
> +#define DRM_FORMAT_SRGGB8	fourcc_code('R', 'G', 'G', 'B')
> +#define DRM_FORMAT_SGRBG8	fourcc_code('G', 'R', 'B', 'G')
> +#define DRM_FORMAT_SGBRG8	fourcc_code('G', 'B', 'R', 'G')
> +#define DRM_FORMAT_SBGGR8	fourcc_code('B', 'A', '8', '1')
> +
> +/* 10-bit Bayer formats */
> +#define DRM_FORMAT_SRGGB10	fourcc_code('R', 'G', '1', '0')
> +#define DRM_FORMAT_SGRBG10	fourcc_code('B', 'A', '1', '0')
> +#define DRM_FORMAT_SGBRG10	fourcc_code('G', 'B', '1', '0')
> +#define DRM_FORMAT_SBGGR10	fourcc_code('B', 'G', '1', '0')
> +
> +/* 12-bit Bayer formats */
> +#define DRM_FORMAT_SRGGB12	fourcc_code('R', 'G', '1', '2')
> +#define DRM_FORMAT_SGRBG12	fourcc_code('B', 'A', '1', '2')
> +#define DRM_FORMAT_SGBRG12	fourcc_code('G', 'B', '1', '2')
> +#define DRM_FORMAT_SBGGR12	fourcc_code('B', 'G', '1', '2')
> +
> +/* 14-bit Bayer formats */
> +#define DRM_FORMAT_SRGGB14	fourcc_code('R', 'G', '1', '4')
> +#define DRM_FORMAT_SGRBG14	fourcc_code('B', 'A', '1', '4')
> +#define DRM_FORMAT_SGBRG14	fourcc_code('G', 'B', '1', '4')
> +#define DRM_FORMAT_SBGGR14	fourcc_code('B', 'G', '1', '4')
> +
>  /*
>   * Format Modifiers:
>   *
> @@ -311,6 +367,7 @@ extern "C" {
>  #define DRM_FORMAT_MOD_VENDOR_BROADCOM 0x07
>  #define DRM_FORMAT_MOD_VENDOR_ARM     0x08
>  #define DRM_FORMAT_MOD_VENDOR_ALLWINNER 0x09
> +#define DRM_FORMAT_MOD_VENDOR_MIPI 0x0a
>
>  /* add more to the end as needed */
>
> @@ -412,6 +469,16 @@ extern "C" {
>  #define I915_FORMAT_MOD_Y_TILED_CCS	fourcc_mod_code(INTEL, 4)
>  #define I915_FORMAT_MOD_Yf_TILED_CCS	fourcc_mod_code(INTEL, 5)
>
> +/*
> + * IPU3 Bayer packing layout
> + *
> + * The IPU3 raw Bayer formats use a custom packing layout where there are no
> + * gaps between each 10-bit sample. It packs 25 pixels into 32 bytes leaving
> + * the 6 most significant bits in the last byte unused. The format is little
> + * endian.
> + */
> +#define IPU3_FORMAT_MOD_PACKED fourcc_mod_code(INTEL, 8)
> +
>  /*
>   * Tiled, NV12MT, grouped in 64 (pixels) x 32 (lines) -sized macroblocks
>   *
> @@ -758,6 +825,33 @@ extern "C" {
>   */
>  #define DRM_FORMAT_MOD_ALLWINNER_TILED fourcc_mod_code(ALLWINNER, 1)
>
> +/* Mobile Industry Processor Interface (MIPI) modifiers */
> +
> +/*
> + * MIPI CSI-2 packing layout
> + *
> + * The CSI-2 RAW formats (for example Bayer) use a different packing layout
> + * depenindg on the sample size.
> + *
> + * - 10-bits per sample
> + *   Every four consecutive samples are packed into 5 bytes. Each of the first 4
> + *   bytes contain the 8 high order bits of the pixels, and the 5th byte
> + *   contains the 2 least-significant bits of each pixel, in the same order.
> + *
> + * - 12-bits per sample
> + *   Every two consecutive samples are packed into three bytes. Each of the
> + *   first two bytes contain the 8 high order bits of the pixels, and the third
> + *   byte contains the four least-significant bits of each pixel, in the same
> + *   order.
> + *
> + * - 14-bits per sample
> + *   Every four consecutive samples are packed into seven bytes. Each of the
> + *   first four bytes contain the eight high order bits of the pixels, and the
> + *   three following bytes contains the six least-significant bits of each
> + *   pixel, in the same order.
> + */
> +#define MIPI_FORMAT_MOD_CSI2_PACKED fourcc_mod_code(MIPI, 1)
> +
>  #if defined(__cplusplus)
>  }
>  #endif
> --
> 2.25.1
>
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