[PATCH 0/6] Initial Rust V4L2 support

Daniel Almeida
2023-04-06T21:58:09Z

Hi all, this is my first attempt at adding Rust support to the
media subsystem.

It adds just enough support to write a clone of the virtio-camera
prototype written by my colleague, Dmitry Osipenko, available at [0].

Basically, there's support for video_device_register,
v4l2_device_register and for some ioctls in v4l2_ioctl_ops. There is
also some initial vb2 support, alongside some wrappers for some types
found in videodev2.h.

I wrote a sample Rust driver just to prove that this probes, and
that you get a message on dmesg whenever an ioctl is called.

As there is no actual implementation for any of the ioctls, this module
can misbehave with some programs. I can work around this in a future
submission.

Note that this is based on the rust branch, as opposed to rust-next. The
reasoning is simple: I expect this series to just kickstart some
discussion around the subject. Actual upstreaming can come up much
later, at which point I can rebase on the rust branch.

Lastly, the origins of this series trace back to a v4l2 virtIO driver I
was writing in Rust. As the project was eventually shelved for other
reasons, I picked both the virtIO and the v4l2 bindings into their own
patches which I am now in the process of submitting. This is to say that
I tested this code with said driver and CrosVM in the past, and it
worked ok.

Please let me know your thoughts.

[0]: https://gitlab.collabora.com/dmitry.osipenko/linux-kernel-rd/-/commit/055a2c322e931a8b388f864f1db81bbdfd525602

Daniel Almeida (6):
rust: media: add the media module
rust: media: add initial videodev2.h abstractions
rust: sync: introduce FfiMutex
rust: media: videobuf2: add a videobuf2 abstraction
rust: media: add {video|v4l2}_device_register support
rust: media: add v4l2 rust sample

rust/bindings/bindings_helper.h | 8 +
rust/kernel/lib.rs | 2 +
rust/kernel/media/mod.rs | 6 +
rust/kernel/media/v4l2/capabilities.rs | 80 ++++
rust/kernel/media/v4l2/dev.rs | 369 +++++++++++++++
rust/kernel/media/v4l2/device.rs | 115 +++++
rust/kernel/media/v4l2/enums.rs | 135 ++++++
rust/kernel/media/v4l2/format.rs | 178 ++++++++
rust/kernel/media/v4l2/framesize.rs | 176 +++++++
rust/kernel/media/v4l2/inputs.rs | 104 +++++
rust/kernel/media/v4l2/ioctls.rs | 608 +++++++++++++++++++++++++
rust/kernel/media/v4l2/mmap.rs | 81 ++++
rust/kernel/media/v4l2/mod.rs | 13 +
rust/kernel/media/videobuf2/core.rs | 552 ++++++++++++++++++++++
rust/kernel/media/videobuf2/mod.rs | 5 +
rust/kernel/sync.rs | 1 +
rust/kernel/sync/ffi_mutex.rs | 70 +++
samples/rust/Kconfig | 11 +
samples/rust/Makefile | 1 +
samples/rust/rust_v4l2.rs | 403 ++++++++++++++++
20 files changed, 2918 insertions(+)
create mode 100644 rust/kernel/media/mod.rs
create mode 100644 rust/kernel/media/v4l2/capabilities.rs
create mode 100644 rust/kernel/media/v4l2/dev.rs
create mode 100644 rust/kernel/media/v4l2/device.rs
create mode 100644 rust/kernel/media/v4l2/enums.rs
create mode 100644 rust/kernel/media/v4l2/format.rs
create mode 100644 rust/kernel/media/v4l2/framesize.rs
create mode 100644 rust/kernel/media/v4l2/inputs.rs
create mode 100644 rust/kernel/media/v4l2/ioctls.rs
create mode 100644 rust/kernel/media/v4l2/mmap.rs
create mode 100644 rust/kernel/media/v4l2/mod.rs
create mode 100644 rust/kernel/media/videobuf2/core.rs
create mode 100644 rust/kernel/media/videobuf2/mod.rs
create mode 100644 rust/kernel/sync/ffi_mutex.rs
create mode 100644 samples/rust/rust_v4l2.rs

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2.40.0