| Message ID | 20221003121852.616745-5-tomi.valkeinen@ideasonboard.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | v4l: routing and streams support | expand |
Hi, On 03/10/2022 17:31, Hans Verkuil wrote: > Hi Tomi, > > On 10/3/22 14:18, Tomi Valkeinen wrote: >> From: Jacopo Mondi <jacopo+renesas@jmondi.org> >> >> Add documentation for VIDIOC_SUBDEV_G/S_ROUTING ioctl and add >> description of multiplexed media pads and internal routing to the >> V4L2-subdev documentation section. >> >> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> >> Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> >> --- >> .../userspace-api/media/v4l/dev-subdev.rst | 2 + >> .../userspace-api/media/v4l/user-func.rst | 1 + >> .../media/v4l/vidioc-subdev-g-routing.rst | 155 ++++++++++++++++++ >> 3 files changed, 158 insertions(+) >> create mode 100644 Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst >> >> diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst >> index fd1de0a73a9f..a67c2749089a 100644 >> --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst >> +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst >> @@ -29,6 +29,8 @@ will feature a character device node on which ioctls can be called to >> >> - negotiate image formats on individual pads >> >> +- inspect and modify internal data routing between pads of the same entity >> + >> Sub-device character device nodes, conventionally named >> ``/dev/v4l-subdev*``, use major number 81. >> >> diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst >> index 53e604bd7d60..228c1521f190 100644 >> --- a/Documentation/userspace-api/media/v4l/user-func.rst >> +++ b/Documentation/userspace-api/media/v4l/user-func.rst >> @@ -70,6 +70,7 @@ Function Reference >> vidioc-subdev-g-crop >> vidioc-subdev-g-fmt >> vidioc-subdev-g-frame-interval >> + vidioc-subdev-g-routing >> vidioc-subdev-g-selection >> vidioc-subdev-querycap >> vidioc-subscribe-event >> diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst >> new file mode 100644 >> index 000000000000..6d8fc3b11352 >> --- /dev/null >> +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst >> @@ -0,0 +1,155 @@ >> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later >> +.. c:namespace:: V4L >> + >> +.. _VIDIOC_SUBDEV_G_ROUTING: >> + >> +****************************************************** >> +ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING >> +****************************************************** >> + >> +Name >> +==== >> + >> +VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity. >> + >> + >> +Synopsis >> +======== >> + >> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp ) >> + :name: VIDIOC_SUBDEV_G_ROUTING >> + >> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp ) >> + :name: VIDIOC_SUBDEV_S_ROUTING >> + >> + >> +Arguments >> +========= >> + >> +``fd`` >> + File descriptor returned by :ref:`open() <func-open>`. >> + >> +``argp`` >> + Pointer to struct :c:type:`v4l2_subdev_routing`. >> + >> + >> +Description >> +=========== >> + >> +These ioctls are used to get and set the routing in a media entity. >> +The routing configuration determines the flows of data inside an entity. >> + >> +Drivers report their current routing tables using the >> +``VIDIOC_SUBDEV_G_ROUTING`` ioctl and application may enable or disable routes >> +with the ``VIDIOC_SUBDEV_S_ROUTING`` ioctl, by adding or removing routes and >> +setting or clearing flags of the ``flags`` field of a >> +struct :c:type:`v4l2_subdev_route`. >> + >> +All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. This >> +means that the userspace mut reconfigure all streams after calling the ioctl > > typo: mut -> must > >> +with e.g. ``VIDIOC_SUBDEV_S_FMT``. >> + >> +A special case for routing are routes marked with >> +``V4L2_SUBDEV_ROUTE_FL_SOURCE`` flag. These routes are used to describe >> +source endpoints on sensors and the sink fields are unused. > > This is very vague. As mentioned in my review for 05/19 I think this flag should > be renamed to INTERNAL_SOURCE. Then the last sentence can change to: > > "These routes are used to describe source endpoints where the stream is internally > created (such as a sensor) and so the sink fields are unused." > >> + >> +When inspecting routes through ``VIDIOC_SUBDEV_G_ROUTING`` and the application >> +provided ``num_routes`` is not big enough to contain all the available routes >> +the subdevice exposes, drivers return the ENOSPC error code and adjust the >> +value of the ``num_routes`` field. Application should then reserve enough memory >> +for all the route entries and call ``VIDIOC_SUBDEV_G_ROUTING`` again. >> + >> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| >> + >> +.. c:type:: v4l2_subdev_routing >> + >> +.. flat-table:: struct v4l2_subdev_routing >> + :header-rows: 0 >> + :stub-columns: 0 >> + :widths: 1 1 2 >> + >> + * - __u32 >> + - ``which`` >> + - Format to modified, from enum >> + :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. >> + * - struct :c:type:`v4l2_subdev_route` >> + - ``routes[]`` >> + - Array of struct :c:type:`v4l2_subdev_route` entries >> + * - __u32 >> + - ``num_routes`` >> + - Number of entries of the routes array >> + * - __u32 >> + - ``reserved``\ [5] >> + - Reserved for future extensions. Applications and drivers must set >> + the array to zero. >> + >> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| >> + >> +.. c:type:: v4l2_subdev_route >> + >> +.. flat-table:: struct v4l2_subdev_route >> + :header-rows: 0 >> + :stub-columns: 0 >> + :widths: 1 1 2 >> + >> + * - __u32 >> + - ``sink_pad`` >> + - Sink pad number. >> + * - __u32 >> + - ``sink_stream`` >> + - Sink pad stream number. >> + * - __u32 >> + - ``source_pad`` >> + - Source pad number. >> + * - __u32 >> + - ``source_stream`` >> + - Source pad stream number. >> + * - __u32 >> + - ``flags`` >> + - Route enable/disable flags >> + :ref:`v4l2_subdev_routing_flags <v4l2-subdev-routing-flags>`. >> + * - __u32 >> + - ``reserved``\ [5] >> + - Reserved for future extensions. Applications and drivers must set >> + the array to zero. >> + >> +.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| >> + >> +.. _v4l2-subdev-routing-flags: >> + >> +.. flat-table:: enum v4l2_subdev_routing_flags >> + :header-rows: 0 >> + :stub-columns: 0 >> + :widths: 3 1 4 >> + >> + * - V4L2_SUBDEV_ROUTE_FL_ACTIVE >> + - 0 >> + - The route is enabled. Set by applications. >> + * - V4L2_SUBDEV_ROUTE_FL_IMMUTABLE >> + - 1 >> + - The route is immutable. Set by the driver. >> + * - V4L2_SUBDEV_ROUTE_FL_SOURCE >> + - 2 >> + - The route is a source route, and the ``sink_pad`` and ``sink_stream`` >> + fields are unused. Set by the driver. > > Same issue as above, it's very vague. > > "Used to describe a route source endpoint where the stream is internally > created (such as a sensor) and so the sink fields are unused." I think this and the above suggestion are good, I'll make the change. Tomi
diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst index fd1de0a73a9f..a67c2749089a 100644 --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst @@ -29,6 +29,8 @@ will feature a character device node on which ioctls can be called to - negotiate image formats on individual pads +- inspect and modify internal data routing between pads of the same entity + Sub-device character device nodes, conventionally named ``/dev/v4l-subdev*``, use major number 81. diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst index 53e604bd7d60..228c1521f190 100644 --- a/Documentation/userspace-api/media/v4l/user-func.rst +++ b/Documentation/userspace-api/media/v4l/user-func.rst @@ -70,6 +70,7 @@ Function Reference vidioc-subdev-g-crop vidioc-subdev-g-fmt vidioc-subdev-g-frame-interval + vidioc-subdev-g-routing vidioc-subdev-g-selection vidioc-subdev-querycap vidioc-subscribe-event diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst new file mode 100644 index 000000000000..6d8fc3b11352 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst @@ -0,0 +1,155 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L + +.. _VIDIOC_SUBDEV_G_ROUTING: + +****************************************************** +ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING +****************************************************** + +Name +==== + +VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity. + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp ) + :name: VIDIOC_SUBDEV_G_ROUTING + +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp ) + :name: VIDIOC_SUBDEV_S_ROUTING + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``argp`` + Pointer to struct :c:type:`v4l2_subdev_routing`. + + +Description +=========== + +These ioctls are used to get and set the routing in a media entity. +The routing configuration determines the flows of data inside an entity. + +Drivers report their current routing tables using the +``VIDIOC_SUBDEV_G_ROUTING`` ioctl and application may enable or disable routes +with the ``VIDIOC_SUBDEV_S_ROUTING`` ioctl, by adding or removing routes and +setting or clearing flags of the ``flags`` field of a +struct :c:type:`v4l2_subdev_route`. + +All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. This +means that the userspace mut reconfigure all streams after calling the ioctl +with e.g. ``VIDIOC_SUBDEV_S_FMT``. + +A special case for routing are routes marked with +``V4L2_SUBDEV_ROUTE_FL_SOURCE`` flag. These routes are used to describe +source endpoints on sensors and the sink fields are unused. + +When inspecting routes through ``VIDIOC_SUBDEV_G_ROUTING`` and the application +provided ``num_routes`` is not big enough to contain all the available routes +the subdevice exposes, drivers return the ENOSPC error code and adjust the +value of the ``num_routes`` field. Application should then reserve enough memory +for all the route entries and call ``VIDIOC_SUBDEV_G_ROUTING`` again. + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. c:type:: v4l2_subdev_routing + +.. flat-table:: struct v4l2_subdev_routing + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``which`` + - Format to modified, from enum + :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. + * - struct :c:type:`v4l2_subdev_route` + - ``routes[]`` + - Array of struct :c:type:`v4l2_subdev_route` entries + * - __u32 + - ``num_routes`` + - Number of entries of the routes array + * - __u32 + - ``reserved``\ [5] + - Reserved for future extensions. Applications and drivers must set + the array to zero. + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. c:type:: v4l2_subdev_route + +.. flat-table:: struct v4l2_subdev_route + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``sink_pad`` + - Sink pad number. + * - __u32 + - ``sink_stream`` + - Sink pad stream number. + * - __u32 + - ``source_pad`` + - Source pad number. + * - __u32 + - ``source_stream`` + - Source pad stream number. + * - __u32 + - ``flags`` + - Route enable/disable flags + :ref:`v4l2_subdev_routing_flags <v4l2-subdev-routing-flags>`. + * - __u32 + - ``reserved``\ [5] + - Reserved for future extensions. Applications and drivers must set + the array to zero. + +.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| + +.. _v4l2-subdev-routing-flags: + +.. flat-table:: enum v4l2_subdev_routing_flags + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * - V4L2_SUBDEV_ROUTE_FL_ACTIVE + - 0 + - The route is enabled. Set by applications. + * - V4L2_SUBDEV_ROUTE_FL_IMMUTABLE + - 1 + - The route is immutable. Set by the driver. + * - V4L2_SUBDEV_ROUTE_FL_SOURCE + - 2 + - The route is a source route, and the ``sink_pad`` and ``sink_stream`` + fields are unused. Set by the driver. + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + +ENOSPC + The application provided ``num_routes`` is not big enough to contain + all the available routes the subdevice exposes. + +EINVAL + The sink or source pad identifiers reference a non-existing pad, or reference + pads of different types (ie. the sink_pad identifiers refers to a source pad) + or the sink or source stream identifiers reference a non-existing stream on + the sink or source pad. + +E2BIG + The application provided ``num_routes`` for ``VIDIOC_SUBDEV_S_ROUTING`` is + larger than the number of routes the driver can handle.