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0171157d45
The patches were generated from the RPi repo with the following command: git format-patch v6.6.44..rpi-6.6.y Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
163 lines
7.1 KiB
Diff
163 lines
7.1 KiB
Diff
From d68e76260316002869aea1b0edf4be399bb592b8 Mon Sep 17 00:00:00 2001
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From: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
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Date: Mon, 29 Jan 2024 17:23:55 +0100
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Subject: [PATCH 1153/1215] media: admin-guide: Document the Raspberry Pi PiSP
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BE
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Add documentation for the PiSP Back End memory-to-memory ISP.
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Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
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---
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.../admin-guide/media/raspberrypi-pisp-be.dot | 20 ++++
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.../admin-guide/media/raspberrypi-pisp-be.rst | 109 ++++++++++++++++++
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.../admin-guide/media/v4l-drivers.rst | 1 +
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3 files changed, 130 insertions(+)
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create mode 100644 Documentation/admin-guide/media/raspberrypi-pisp-be.dot
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create mode 100644 Documentation/admin-guide/media/raspberrypi-pisp-be.rst
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--- /dev/null
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+++ b/Documentation/admin-guide/media/raspberrypi-pisp-be.dot
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@@ -0,0 +1,20 @@
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+digraph board {
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+ rankdir=TB
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+ n00000001 [label="{{<port0> 0 | <port1> 1 | <port2> 2 | <port7> 7} | pispbe\n | {<port3> 3 | <port4> 4 | <port5> 5 | <port6> 6}}", shape=Mrecord, style=filled, fillcolor=green]
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+ n00000001:port3 -> n0000001c [style=bold]
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+ n00000001:port4 -> n00000022 [style=bold]
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+ n00000001:port5 -> n00000028 [style=bold]
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+ n00000001:port6 -> n0000002e [style=bold]
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+ n0000000a [label="pispbe-input\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
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+ n0000000a -> n00000001:port0 [style=bold]
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+ n00000010 [label="pispbe-tdn_input\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
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+ n00000010 -> n00000001:port1 [style=bold]
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+ n00000016 [label="pispbe-stitch_input\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
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+ n00000016 -> n00000001:port2 [style=bold]
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+ n0000001c [label="pispbe-output0\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
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+ n00000022 [label="pispbe-output1\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
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+ n00000028 [label="pispbe-tdn_output\n/dev/video5", shape=box, style=filled, fillcolor=yellow]
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+ n0000002e [label="pispbe-stitch_output\n/dev/video6", shape=box, style=filled, fillcolor=yellow]
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+ n00000034 [label="pispbe-config\n/dev/video7", shape=box, style=filled, fillcolor=yellow]
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+ n00000034 -> n00000001:port7 [style=bold]
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+}
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--- /dev/null
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+++ b/Documentation/admin-guide/media/raspberrypi-pisp-be.rst
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@@ -0,0 +1,109 @@
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+.. SPDX-License-Identifier: GPL-2.0
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+
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+=========================================================
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+Raspberry Pi PiSP Back End Memory-to-Memory ISP (pisp-be)
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+=========================================================
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+
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+The PiSP Back End
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+=================
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+
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+The PiSP Back End is a memory-to-memory Image Signal Processor (ISP) which reads
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+image data from DRAM memory and performs image processing as specified by the
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+application through the parameters in a configuration buffer, before writing
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+pixel data back to memory through two distinct output channels.
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+
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+The ISP registers and programming model are documented in the `Raspberry Pi
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+Image Signal Processor (PiSP) Specification document`_
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+
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+The PiSP Back End ISP processes images in tiles. The handling of image
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+tessellation and the computation of low-level configuration parameters is
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+realized by a free software library called `libpisp
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+<https://github.com/raspberrypi/libpisp>`_.
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+
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+The full image processing pipeline, which involves capturing RAW Bayer data from
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+an image sensor through a MIPI CSI-2 compatible capture interface, storing them
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+in DRAM memory and processing them in the PiSP Back End to obtain images usable
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+by an application is implemented in `libcamera <https://libcamera.org>`_ as
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+part of the Raspberry Pi platform support.
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+
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+The pisp-be driver
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+==================
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+
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+The Raspberry Pi PiSP Back End (pisp-be) driver is located under
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+drivers/media/platform/raspberrypi/pisp-be. It uses the `V4L2 API` to register
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+a number of video capture and output devices, the `V4L2 subdev API` to register
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+a subdevice for the ISP that connects the video devices in a single media graph
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+realized using the `Media Controller (MC) API`.
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+
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+The media topology registered by the `pisp-be` driver is represented below:
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+
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+.. _pips-be-topology:
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+
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+.. kernel-figure:: raspberrypi-pisp-be.dot
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+ :alt: Diagram of the default media pipeline topology
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+ :align: center
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+
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+
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+The media graph registers the following video device nodes:
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+
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+- pispbe-input: output device for images to be submitted to the ISP for
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+ processing.
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+- pispbe-tdn_input: output device for temporal denoise.
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+- pispbe-stitch_input: output device for image stitching (HDR).
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+- pispbe-output0: first capture device for processed images.
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+- pispbe-output1: second capture device for processed images.
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+- pispbe-tdn_output: capture device for temporal denoise.
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+- pispbe-stitch_output: capture device for image stitching (HDR).
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+- pispbe-config: output device for ISP configuration parameters.
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+
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+pispbe-input
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+------------
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+
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+Images to be processed by the ISP are queued to the `pispbe-input` output device
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+node. For a list of image formats supported as input to the ISP refer to the
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+`Raspberry Pi Image Signal Processor (PiSP) Specification document`_.
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+
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+pispbe-tdn_input, pispbe-tdn_output
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+-----------------------------------
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+
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+The `pispbe-tdn_input` output video device receives images to be processed by
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+the temporal denoise block which are captured from the `pispbe-tdn_output`
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+capture video device. Userspace is responsible for maintaining queues on both
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+devices, and ensuring that buffers completed on the output are queued to the
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+input.
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+
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+pispbe-stitch_input, pispbe-stitch_output
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+-----------------------------------------
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+
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+To realize HDR (high dynamic range) image processing the image stitching and
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+tonemapping blocks are used. The `pispbe-stitch_output` writes images to memory
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+and the `pispbe-stitch_input` receives the previously written frame to process
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+it along with the current input image. Userspace is responsible for maintaining
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+queues on both devices, and ensuring that buffers completed on the output are
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+queued to the input.
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+
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+pispbe-output0, pispbe-output1
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+------------------------------
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+
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+The two capture devices write to memory the pixel data as processed by the ISP.
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+
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+pispbe-config
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+-------------
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+
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+The `pispbe-config` output video devices receives a buffer of configuration
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+parameters that define the desired image processing to be performed by the ISP.
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+
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+The format of the ISP configuration parameter is defined by
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+:c:type:`pisp_be_tiles_config` C structure and the meaning of each parameter is
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+described in the `Raspberry Pi Image Signal Processor (PiSP) Specification
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+document`_.
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+
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+ISP configuration
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+=================
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+
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+The ISP configuration is described solely by the content of the parameters
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+buffer. The only parameter that userspace needs to configure using the V4L2 API
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+is the image format on the output and capture video devices for validation of
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+the content of the parameters buffer.
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+
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+.. _Raspberry Pi Image Signal Processor (PiSP) Specification document: https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf
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--- a/Documentation/admin-guide/media/v4l-drivers.rst
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+++ b/Documentation/admin-guide/media/v4l-drivers.rst
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@@ -21,6 +21,7 @@ Video4Linux (V4L) driver-specific docume
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omap4_camera
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philips
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qcom_camss
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+ raspberrypi-pisp-be
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rcar-fdp1
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rkisp1
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saa7134
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