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57 lines
2.3 KiB
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57 lines
2.3 KiB
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.. SPDX-License-Identifier: GPL-2.0
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.. _v4l2-meta-fmt-rpi-be-cfg:
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************************
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V4L2_META_FMT_RPI_BE_CFG
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************************
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Raspberry Pi PiSP Back End configuration format
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===============================================
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The Raspberry Pi PiSP Back End memory-to-memory image signal processor is
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configured by userspace by providing a buffer of configuration parameters
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to the `pispbe-config` output video device node using the
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:c:type:`v4l2_meta_format` interface.
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The PiSP Back End processes images in tiles, and its configuration requires
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specifying two different sets of parameters by populating the members of
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:c:type:`pisp_be_tiles_config` defined in the ``pisp_be_config.h`` header file.
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The `Raspberry Pi PiSP technical specification
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<https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf>`_
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provide detailed description of the ISP back end configuration and programming
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model.
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Global configuration data
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-------------------------
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The global configuration data describe how the pixels in a particular image are
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to be processed and is therefore shared across all the tiles of the image. So
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for example, LSC (Lens Shading Correction) or Denoise parameters would be common
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across all tiles from the same frame.
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Global configuration data are passed to the ISP by populating the member of
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:c:type:`pisp_be_config`.
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Tile parameters
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---------------
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As the ISP processes images in tiles, each set of tiles parameters describe how
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a single tile in an image is going to be processed. A single set of tile
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parameters consist of 160 bytes of data and to process a batch of tiles several
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sets of tiles parameters are required.
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Tiles parameters are passed to the ISP by populating the member of
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``pisp_tile`` and the ``num_tiles`` fields of :c:type:`pisp_be_tiles_config`.
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Raspberry Pi PiSP Back End uAPI data types
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==========================================
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This section describes the data types exposed to userspace by the Raspberry Pi
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PiSP Back End. The section is informative only, for a detailed description of
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each field refer to the `Raspberry Pi PiSP technical specification
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<https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf>`_.
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.. kernel-doc:: include/uapi/linux/media/raspberrypi/pisp_be_config.h
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