pipeline: ipa: raspberrypi: Refactor and move the Raspberry Pi code

Split the Raspberry Pi pipeline handler and IPA source code into common
and VC4/BCM2835 specific file structures.

For the pipeline handler, the common code files now live in
src/libcamera/pipeline/rpi/common/
and the VC4-specific files in src/libcamera/pipeline/rpi/vc4/.

For the IPA, the common code files now live in
src/ipa/rpi/{cam_helper,controller}/
and the vc4 specific files in src/ipa/rpi/vc4/. With this change, the
camera tuning files are now installed under share/libcamera/ipa/rpi/vc4/.

To build the pipeline and IPA, the meson configuration options have now
changed from "raspberrypi" to "rpi/vc4":

meson setup build -Dipas=rpi/vc4 -Dpipelines=rpi/vc4

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Documentation/environment_variables.rst

@@ -40,7 +40,7 @@ LIBCAMERA_IPA_MODULE_PATH
 LIBCAMERA_RPI_CONFIG_FILE
    Define a custom configuration file to use in the Raspberry Pi pipeline handler.
 
-   Example value: ``/usr/local/share/libcamera/pipeline/raspberrypi/minimal_mem.yaml``
+   Example value: ``/usr/local/share/libcamera/pipeline/rpi/vc4/minimal_mem.yaml``
 
 Further details
 ---------------
@@ -143,7 +143,7 @@ contain tuning parameters for the algorithms, in JSON format.
 The ``LIBCAMERA_IPA_CONFIG_PATH`` variable can be used to specify custom
 storage locations to search for those configuration files.
 
-`Examples <https://git.libcamera.org/libcamera/libcamera.git/tree/src/ipa/raspberrypi/data>`__
+`Examples <https://git.libcamera.org/libcamera/libcamera.git/tree/src/ipa/rpi/vc4/data>`__
 
 IPA module
 ~~~~~~~~~~

Documentation/guides/introduction.rst

@@ -288,7 +288,7 @@ with dedicated pipeline handlers:
 
    -  Intel IPU3 (ipu3)
    -  Rockchip RK3399 (rkisp1)
-   -  RaspberryPi 3 and 4 (raspberrypi)
+   -  RaspberryPi 3 and 4 (rpi/vc4)
 
 Furthermore, generic platform support is provided for the following:
 

Documentation/guides/pipeline-handler.rst

@@ -183,7 +183,7 @@ to the libcamera build options in the top level ``meson_options.txt``.
 
    option('pipelines',
            type : 'array',
-           choices : ['ipu3', 'raspberrypi', 'rkisp1', 'simple', 'uvcvideo', 'vimc', 'vivid'],
+           choices : ['ipu3', 'rkisp1', 'rpi/vc4', 'simple', 'uvcvideo', 'vimc', 'vivid'],
            description : 'Select which pipeline handlers to include')