Hi Laurent, Thanks for the review! On Fri, Apr 19, 2024 at 09:49:26PM +0300, Laurent Pinchart wrote: > Hi Sakari, > > Thank you for the patch. > > On Tue, Apr 16, 2024 at 10:32:43PM +0300, Sakari Ailus wrote: > > Document internal sink pads, pads that have both SINK and INTERNAL flags > > set. Use the IMX219 camera sensor as an example. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > Reviewed-by Julien Massot <julien.massot@xxxxxxxxxxxxx> > > --- > > .../userspace-api/media/v4l/dev-subdev.rst | 145 ++++++++++++++++++ > > 1 file changed, 145 insertions(+) > > > > diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst > > index b76e02e54512..d30dcb9e2537 100644 > > --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst > > +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst > > @@ -553,6 +553,27 @@ A stream at a specific point in the media pipeline is identified by the > > sub-device and a (pad, stream) pair. For sub-devices that do not support > > multiplexed streams the 'stream' field is always 0. > > > > +.. _v4l2-subdev-internal-source-pads: > > + > > +Internal sink pads and routing > > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > + > > +Cases where a single sub-device source pad is traversed by multiple streams, one > > +or more of which originate from within the sub-device itself, are special as > > +there is no external sink pad for such routes. In those cases, the sources of > > +the internally generated streams are represented by internal sink pads, which > > +are sink pads that have the :ref:`MEDIA_PAD_FL_INTERNAL <MEDIA-PAD-FL-INTERNAL>` > > +pad flag set. > > + > > +Internal pads have all the properties of an external pad, including formats and > > +selections. The format in this case is the source format of the stream. An > > +internal pad always has a single stream only (0). > > + > > +Routes from an internal sink pad to an external source pad are typically not > > +modifiable but they can be activated and deactivated using the > > +:ref:`V4L2_SUBDEV_ROUTE_FL_ACTIVE <v4l2-subdev-routing-flags>` flag, depending > > +on driver capabilities. > > + > > Interaction between routes, streams, formats and selections > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > > @@ -668,3 +689,127 @@ To configure this pipeline, the userspace must take the following steps: > > the configurations along the stream towards the receiver, using > > :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>` ioctls to configure each > > stream endpoint in each sub-device. > > + > > +Internal pads setup example > > +^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > + > > +A simple example of a multiplexed stream setup might be as follows: > > + > > +- An IMX219 camera sensor source sub-device, with one source pad (0), one > > + internal sink pad (1) as the source of the image data and an internal sink > > + pad (2) as the source of the embedded data. There are two routes, one from the > > + internal sink pad 1 to the source 0 (image data) and another from the internal > > s/source 0/source pad 0/ Yes. > > > + sink pad 2 to the source pad 0 (embedded data). Both streams are always > > + active, i.e. there is no need to separately enable the embedded data > > + stream. The sensor uses the CSI-2 interface. > > + > > +- A CSI-2 receiver in the SoC. The receiver has a single sink pad (pad 0), > > + connected to the sensor, and two source pads (pads 1 and 2), to the DMA > > + engine. The receiver demultiplexes the incoming streams to the source pads. > > s/engine/engines/ > > maybe better, "to two DMA engines". "to the two DMA engines". > > > + > > +- DMA engines in the SoC, one for each stream. Each DMA engine is connected to a > > + single source pad of the receiver. > > + > > +The sensor and the receiver are modelled as V4L2 sub-devices, exposed to > > +userspace via /dev/v4l-subdevX device nodes. The DMA engines are modelled as > > +V4L2 devices, exposed to userspace via /dev/videoX nodes. > > + > > +To configure this pipeline, the userspace must take the following steps: > > + > > +1) Set up media links between entities: enable the links from the sensor to the > > + receiver and from the receiver to the DMA engines. This step does not differ > > + from normal non-multiplexed media controller setup. > > + > > +2) Configure routing > > + > > +.. flat-table:: Camera sensor. There are no configurable routes. > > + :header-rows: 1 > > + > > + * - Sink Pad/Stream > > + - Source Pad/Stream > > + - Routing Flags > > + - Comments > > + * - 1/0 > > + - 0/0 > > + - V4L2_SUBDEV_ROUTE_FL_ACTIVE > > + - Pixel data stream from the sink pad > > "from the internal image sink pad" > > > + * - 2/0 > > + - 0/1 > > + - V4L2_SUBDEV_ROUTE_FL_ACTIVE > > + - Metadata stream from the internal sink pad > > "internal embedded data sink pad" Yes... > > > + > > +.. flat-table:: Receiver routing table. Typically both routes need to be > > + explicitly set. > > + :header-rows: 1 > > + > > + * - Sink Pad/Stream > > + - Source Pad/Stream > > + - Routing Flags > > + - Comments > > + * - 0/0 > > + - 1/0 > > + - V4L2_SUBDEV_ROUTE_FL_ACTIVE > > + - Pixel data stream from camera sensor > > + * - 0/1 > > + - 2/0 > > + - V4L2_SUBDEV_ROUTE_FL_ACTIVE > > + - Metadata stream from camera sensor > > + > > +The options available in sensor's routing configuration are dictated by hardware > > s/in sensor/in the sensor/ Agreed. > > > +capabilities: typically camera sensors always produce an image data stream while > > +it may be possible to enable and disable the embedded data stream. > > Should this go after the first table ? I'll move it there. > > > + > > +3) Configure formats and selections > > + > > + This example assumes that the formats are propagated from sink pad to the > > + source pad as-is. The tables contain fields of both struct v4l2_subdev_format > > + and struct v4l2_mbus_framefmt. > > + > > +.. flat-table:: Formats set on the sub-devices. Bold values are set, others are > > + static or propagated. The order is aligned with configured > > + routes. > > + :header-rows: 1 > > + :fill-cells: > > + > > + * - Sub-device > > + - Pad/Stream > > + - Width > > + - Height > > + - Code > > + * - :rspan:`3` IMX219 > > + - 1/0 > > + - 3296 > > + - 2480 > > + - MEDIA_BUS_FMT_SRGGB10 > > + * - 0/0 > > + - **3296** > > + - **2480** > > + - **MEDIA_BUS_FMT_SRGGB10** > > + * - 2/0 > > + - 3296 > > + - 2 > > + - MEDIA_BUS_FMT_IMX219_EMBEDDED > > We need a patch in this series to define this format. I'm waiting for your imx290 patches. :-) > > > + * - 1/1 > > I think this should be 0/1. Good catch. > > > + - 3296 > > + - 2 > > + - MEDIA_BUS_FMT_META_10 > > + * - :rspan:`3` CSI-2 receiver > > + - 0/0 > > + - **3296** > > + - **2480** > > + - **MEDIA_BUS_FMT_SRGGB10** > > + * - 1/0 > > + - 3296 > > + - 2480 > > + - MEDIA_BUS_FMT_SRGGB10 > > + * - 0/1 > > + - **3296** > > + - **2** > > + - **MEDIA_BUS_FMT_META_10** > > + * - 2/0 > > + - 3296 > > + - 2 > > + - MEDIA_BUS_FMT_META_10 > > + > > +The embedded data format does not need to be configured as the format is > > Do you mean the "format on the sensor's pads" ? It's a bit confusing if > you don't specify it. That's what was meant, I'll add that. > > > +dictated by the pixel data format in this case. > -- Regards, Sakari Ailus
