1.. SPDX-License-Identifier: GPL-2.0 2 3.. _v4l2-meta-fmt-rpi-be-cfg: 4 5************************ 6V4L2_META_FMT_RPI_BE_CFG 7************************ 8 9Raspberry Pi PiSP Back End configuration format 10=============================================== 11 12The Raspberry Pi PiSP Back End memory-to-memory image signal processor is 13configured by userspace by providing a buffer of configuration parameters 14to the `pispbe-config` output video device node using the 15:c:type:`v4l2_meta_format` interface. 16 17The PiSP Back End processes images in tiles, and its configuration requires 18specifying two different sets of parameters by populating the members of 19:c:type:`pisp_be_tiles_config` defined in the ``pisp_be_config.h`` header file. 20 21The `Raspberry Pi PiSP technical specification 22<https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf>`_ 23provide detailed description of the ISP back end configuration and programming 24model. 25 26Global configuration data 27------------------------- 28 29The global configuration data describe how the pixels in a particular image are 30to be processed and is therefore shared across all the tiles of the image. So 31for example, LSC (Lens Shading Correction) or Denoise parameters would be common 32across all tiles from the same frame. 33 34Global configuration data are passed to the ISP by populating the member of 35:c:type:`pisp_be_config`. 36 37Tile parameters 38--------------- 39 40As the ISP processes images in tiles, each set of tiles parameters describe how 41a single tile in an image is going to be processed. A single set of tile 42parameters consist of 160 bytes of data and to process a batch of tiles several 43sets of tiles parameters are required. 44 45Tiles parameters are passed to the ISP by populating the member of 46``pisp_tile`` and the ``num_tiles`` fields of :c:type:`pisp_be_tiles_config`. 47 48Raspberry Pi PiSP Back End uAPI data types 49========================================== 50 51This section describes the data types exposed to userspace by the Raspberry Pi 52PiSP Back End. The section is informative only, for a detailed description of 53each field refer to the `Raspberry Pi PiSP technical specification 54<https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf>`_. 55 56.. kernel-doc:: include/uapi/linux/media/raspberrypi/pisp_be_config.h 57