From 3fe819eecfc6fce45aed35708affb3aa8fa1095e Mon Sep 17 00:00:00 2001
From: Daniel Scally <dan.scally@ideasonboard.com>
Date: Tue, 20 Aug 2024 14:07:36 +0100
Subject: Documentation: Remove libcamera architecture from introduction.rst
The libcamera Architecture section of the introduction is largely a
duplicate of the section broken out from docs.rst. Remove it from the
introduction.rst file and consolidate anything that wasn't duplicated
into libcamera_architecture.rst and feature_requirements.rst. Take the
opportunity to also expand the list of Platform Support which is now a
bit out of date.
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
Documentation/guides/introduction.rst | 156 +---------------------------------
1 file changed, 2 insertions(+), 154 deletions(-)
(limited to 'Documentation/guides')
diff --git a/Documentation/guides/introduction.rst b/Documentation/guides/introduction.rst
index d1e67654..12d1b7d4 100644
--- a/Documentation/guides/introduction.rst
+++ b/Documentation/guides/introduction.rst
@@ -26,10 +26,8 @@ desirable results from the camera.
.. _Media Controller: https://www.linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/mediactl/media-controller.html
-In this developers guide, we will explore the internal `Architecture`_ of
-the libcamera library with its components. The current `Platform Support`_ is
-detailed, as well as an overview of the `Licensing`_ requirements of the
-project.
+In this developers guide the `Licensing`_ requirements of the project are
+detailed.
This introduction is followed by a walkthrough tutorial to newcomers wishing to
support a new platform with the `Pipeline Handler Writers Guide`_ and for those
@@ -41,156 +39,6 @@ provides a tutorial of the key APIs exposed by libcamera.
.. TODO: Correctly link to the other articles of the guide
-Architecture
-------------
-
-While offering a unified API towards upper layers, and presenting itself as a
-single library, libcamera isn't monolithic. It exposes multiple components
-through its public API and is built around a set of separate helpers internally.
-Hardware abstractions are handled through the use of device-specific components
-where required and dynamically loadable plugins are used to separate image
-processing algorithms from the core libcamera codebase.
-
-::
-
- --------------------------< libcamera Public API >---------------------------
- ^ ^
- | |
- v v
- +-------------+ +---------------------------------------------------+
- | Camera | | Camera Device |
- | Manager | | +-----------------------------------------------+ |
- +-------------+ | | Device-Agnostic | |
- ^ | | | |
- | | | +--------------------------+ |
- | | | | ~~~~~~~~~~~~~~~~~~~~~~~ |
- | | | | { +-----------------+ } |
- | | | | } | //// Image //// | { |
- | | | | <-> | / Processing // | } |
- | | | | } | / Algorithms // | { |
- | | | | { +-----------------+ } |
- | | | | ~~~~~~~~~~~~~~~~~~~~~~~ |
- | | | | ========================== |
- | | | | +-----------------+ |
- | | | | | // Pipeline /// | |
- | | | | <-> | /// Handler /// | |
- | | | | | /////////////// | |
- | | +--------------------+ +-----------------+ |
- | | Device-Specific |
- | +---------------------------------------------------+
- | ^ ^
- | | |
- v v v
- +--------------------------------------------------------------------+
- | Helpers and Support Classes |
- | +-------------+ +-------------+ +-------------+ +-------------+ |
- | | MC & V4L2 | | Buffers | | Sandboxing | | Plugins | |
- | | Support | | Allocator | | IPC | | Manager | |
- | +-------------+ +-------------+ +-------------+ +-------------+ |
- | +-------------+ +-------------+ |
- | | Pipeline | | ... | |
- | | Runner | | | |
- | +-------------+ +-------------+ |
- +--------------------------------------------------------------------+
-
- /// Device-Specific Components
- ~~~ Sandboxing
-
-
-Camera Manager
- The Camera Manager enumerates cameras and instantiates Pipeline Handlers to
- manage each Camera that libcamera supports. The Camera Manager supports
- hotplug detection and notification events when supported by the underlying
- kernel devices.
-
- There is only ever one instance of the Camera Manager running per application.
- Each application's instance of the Camera Manager ensures that only a single
- application can take control of a camera device at once.
-
- Read the `Camera Manager API`_ documentation for more details.
-
-.. _Camera Manager API: https://libcamera.org/api-html/classlibcamera_1_1CameraManager.html
-
-Camera Device
- The Camera class represents a single item of camera hardware that is capable
- of producing one or more image streams, and provides the API to interact with
- the underlying device.
-
- If a system has multiple instances of the same hardware attached, each has its
- own instance of the camera class.
-
- The API exposes full control of the device to upper layers of libcamera through
- the public API, making it the highest level object libcamera exposes, and the
- object that all other API operations interact with from configuration to
- capture.
-
- Read the `Camera API`_ documentation for more details.
-
-.. _Camera API: https://libcamera.org/api-html/classlibcamera_1_1Camera.html
-
-Pipeline Handler
- The Pipeline Handler manages the complex pipelines exposed by the kernel
- drivers through the Media Controller and V4L2 APIs. It abstracts pipeline
- handling to hide device-specific details from the rest of the library, and
- implements both pipeline configuration based on stream configuration, and
- pipeline runtime execution and scheduling when needed by the device.
-
- The Pipeline Handler lives in the same process as the rest of the library, and
- has access to all helpers and kernel camera-related devices.
-
- Hardware abstraction is handled by device specific Pipeline Handlers which are
- derived from the Pipeline Handler base class allowing commonality to be shared
- among the implementations.
-
- Derived pipeline handlers create Camera device instances based on the devices
- they detect and support on the running system, and are responsible for
- managing the interactions with a camera device.
-
- More details can be found in the `PipelineHandler API`_ documentation, and the
- `Pipeline Handler Writers Guide`_.
-
-.. _PipelineHandler API: https://libcamera.org/api-html/classlibcamera_1_1PipelineHandler.html
-
-Image Processing Algorithms
- An image processing algorithm (IPA) component is a loadable plugin that
- implements 3A (Auto-Exposure, Auto-White Balance, and Auto-Focus) and other
- algorithms.
-
- The algorithms run on the CPU and interact with the camera devices through the
- Pipeline Handler to control hardware image processing based on the parameters
- supplied by upper layers, maintaining state and closing the control loop
- of the ISP.
-
- The component is sandboxed and can only interact with libcamera through the
- API provided by the Pipeline Handler and an IPA has no direct access to kernel
- camera devices.
-
- Open source IPA modules built with libcamera can be run in the same process
- space as libcamera, however external IPA modules are run in a separate process
- from the main libcamera process. IPA modules have a restricted view of the
- system, including no access to networking APIs and limited access to file
- systems.
-
- IPA modules are only required for platforms and devices with an ISP controlled
- by the host CPU. Camera sensors which have an integrated ISP are not
- controlled through the IPA module.
-
-Platform Support
-----------------
-
-The library currently supports the following hardware platforms specifically
-with dedicated pipeline handlers:
-
- - Intel IPU3 (ipu3)
- - Rockchip RK3399 (rkisp1)
- - RaspberryPi 3 and 4 (rpi/vc4)
-
-Furthermore, generic platform support is provided for the following:
-
- - USB video device class cameras (uvcvideo)
- - iMX7, Allwinner Sun6i (simple)
- - Virtual media controller driver for test use cases (vimc)
-
Licensing
---------
--
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