Hi Tomi, I'm very happy to see this being worked on again! Is there code somewhere that demonstrates the v5 API in use? I still have old branches of this series and it would be nice to see how the API have evolved for drivers. Likewise are there some user-space code around that can be used to test the API? For v2 and v3 I had some hack patches [1], do they still work? More likely they have gone stale by now :-) 1. git://git.ragnatech.se/v4l-utils routing On 2021-04-15 16:04:26 +0300, Tomi Valkeinen wrote: > Hi, > > This is an RFC for subdev internal routing which is needed for > multiplexed streams support. I believe this is essentially a v5 of the > series, the v4 posted here: > > https://lore.kernel.org/linux-media/20190328200608.9463-1-jacopo+renesas@xxxxxxxxxx/ > > Most of the patches are not changed (aside from fixing rebase issues > etc). The major changes in this version are: > > 1) Added 'which' field to the routing structs. It is currently not used, > as implementing it is not trivial. However, I think it's good to add it > to the uAPI now, and require the field to be set to > V4L2_SUBDEV_FORMAT_ACTIVE for now. See this RFC for an idea how this > could be implemented: > > https://lore.kernel.org/linux-media/20210409133659.389544-1-tomi.valkeinen@xxxxxxxxxxxxxxxx/ > > 2) No hardcoded maximum number of routes. Defining a maximum is not > possible, as there can be an arbitrary amount of routes per pad, and > there can be an arbitrary amount of pads per subdev. This series > allocates space for the routing table dynamically, which unfortunately > leads to not-just-a-few allocs and frees. > > 3) When searching for a format for a stream, the v4 looked for a > non-multiplexed pad only as far as the "other" side of the subdev. It > wouldn't work for a subdev which has multiplexed sink and source pads. > This series implements a "deep" get-format (v4l2_subdev_get_format_dir) > which follows a stream either towards the original source or the final > sink, while looking for a non-multiplexed pad with a format. > > Some thoughts: > > 1) Link validation and v4l2_subdev_get_format_dir need to look at the > routing, and this leads to multiple allocs to get a copy of the routing > table. There might be a possibility here to keep a table allocated and > re-use it in consecutive get_routing calls. > > Or even better, perhaps the kAPI could be changed so that allocs are not > needed. I thought about a kAPI where the subdev just returns a pointer > to its routing table, but then we hit the life-cycle problem: how to > ensure the table won't be freed or changed until the caller is done. > > 2) The routing uAPI is a bit vague. There is no way for the userspace to > figure out what kind of routing is allowed. Also, the existence of a > route in the routing table already indicates that the route is active, > but we also have V4L2_SUBDEV_ROUTE_FL_ACTIVE. I decided to keep > V4L2_SUBDEV_ROUTE_FL_ACTIVE for now, even if it doesn't really provide > any feature. > > 3) V4L2_FRAME_DESC_ENTRY_MAX is defined as 8 (I change it from 4 to 8 in > this series). This limits the number of streams per pad to 8. Preferably > the number of frame descs would be unlimited, but I didn't start > tackling this. I believe 8 is quite safe number (4 pixel streams and 4 > embedded data stream). > > 4) Link validation ends up following the same routes multiple times, as > each stream in each subdev is validated separately. > > Tomi > > Jacopo Mondi (2): > media: entity: Add iterator helper for entity pads > media: Documentation: Add GS_ROUTING documentation > > Laurent Pinchart (4): > media: entity: Add has_route entity operation > media: entity: Add media_entity_has_route() function > media: entity: Use routing information during graph traversal > v4l: subdev: Add [GS]_ROUTING subdev ioctls and operations > > Sakari Ailus (14): > media: entity: Use pad as a starting point for graph walk > media: entity: Use pads instead of entities in the media graph walk > stack > media: entity: Walk the graph based on pads > v4l: mc: Start walk from a specific pad in use count calculation > media: entity: Move the pipeline from entity to pads > media: entity: Use pad as the starting point for a pipeline > media: entity: Skip link validation for pads to which there is no > route to > media: entity: Add an iterator helper for connected pads > media: entity: Add only connected pads to the pipeline > media: entity: Add debug information in graph walk route check > v4l: Add bus type to frame descriptors > v4l: Add CSI-2 bus configuration to frame descriptors > v4l: Add stream to frame descriptor > v4l: mc: Add an S_ROUTING helper function for power state changes > > Tomi Valkeinen (4): > v4l: subdev: routing kernel helper functions > v4l: subdev: add v4l2_subdev_get_format_dir() > v4l: subdev: Take routing information into account in link validation > v4l: subdev: increase V4L2_FRAME_DESC_ENTRY_MAX to 8 > > Documentation/driver-api/media/mc-core.rst | 15 +- > .../userspace-api/media/v4l/dev-subdev.rst | 92 +++++ > .../userspace-api/media/v4l/user-func.rst | 1 + > .../media/v4l/vidioc-subdev-g-routing.rst | 143 +++++++ > drivers/media/mc/mc-device.c | 13 +- > drivers/media/mc/mc-entity.c | 239 +++++++----- > drivers/media/pci/intel/ipu3/ipu3-cio2-main.c | 6 +- > .../media/platform/exynos4-is/fimc-capture.c | 8 +- > .../platform/exynos4-is/fimc-isp-video.c | 8 +- > drivers/media/platform/exynos4-is/fimc-isp.c | 2 +- > drivers/media/platform/exynos4-is/fimc-lite.c | 10 +- > drivers/media/platform/exynos4-is/media-dev.c | 20 +- > drivers/media/platform/omap3isp/isp.c | 2 +- > drivers/media/platform/omap3isp/ispvideo.c | 25 +- > drivers/media/platform/omap3isp/ispvideo.h | 2 +- > .../media/platform/qcom/camss/camss-video.c | 6 +- > drivers/media/platform/rcar-vin/rcar-core.c | 16 +- > drivers/media/platform/rcar-vin/rcar-dma.c | 8 +- > .../platform/rockchip/rkisp1/rkisp1-capture.c | 6 +- > .../media/platform/s3c-camif/camif-capture.c | 6 +- > drivers/media/platform/stm32/stm32-dcmi.c | 6 +- > .../platform/sunxi/sun4i-csi/sun4i_dma.c | 6 +- > .../platform/sunxi/sun6i-csi/sun6i_video.c | 6 +- > drivers/media/platform/ti-vpe/cal-video.c | 6 +- > drivers/media/platform/vsp1/vsp1_video.c | 18 +- > drivers/media/platform/xilinx/xilinx-dma.c | 20 +- > drivers/media/platform/xilinx/xilinx-dma.h | 2 +- > .../media/test-drivers/vimc/vimc-capture.c | 6 +- > drivers/media/usb/au0828/au0828-core.c | 8 +- > drivers/media/v4l2-core/v4l2-ioctl.c | 25 +- > drivers/media/v4l2-core/v4l2-mc.c | 77 ++-- > drivers/media/v4l2-core/v4l2-subdev.c | 368 ++++++++++++++++++ > drivers/staging/media/imx/imx-media-utils.c | 8 +- > drivers/staging/media/ipu3/ipu3-v4l2.c | 6 +- > drivers/staging/media/omap4iss/iss.c | 2 +- > drivers/staging/media/omap4iss/iss_video.c | 38 +- > drivers/staging/media/omap4iss/iss_video.h | 2 +- > drivers/staging/media/tegra-video/tegra210.c | 6 +- > include/media/media-entity.h | 143 +++++-- > include/media/v4l2-mc.h | 22 ++ > include/media/v4l2-subdev.h | 93 ++++- > include/uapi/linux/v4l2-subdev.h | 44 +++ > 42 files changed, 1241 insertions(+), 299 deletions(-) > create mode 100644 Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst > > -- > 2.25.1 > -- Regards, Niklas Söderlund
