[PATCH v7 0/6] rust: add support for request_irq

[Daniel Almeida <daniel.almeida@collabora.com>]

Changes in v7:
- Rebased on top of driver-core-next
- Added Flags::new(), which is a const fn. This lets us use build_assert!()
  to verify the casts (hopefully this is what you meant, Alice?)
- Changed the Flags inner type to take c_ulong directly, to minimize casts
  (Thanks, Alice)
- Moved the flag constants into Impl Flags, instead of using a separate
  module (Alice)
- Reverted to using #[repr(u32)] in Threaded/IrqReturn (Thanks Alice,
  Benno)
- Fixed all instances where the full path was specified for types in the
  prelude (Alice)
- Removed 'static from the CStr used to perform the lookup in the platform
  accessor (Alice)
- Renamed the PCI accessors, as asked by Danilo
- Added more docs to Flags, going into more detail on what they do and how
  to use them (Miguel)
- Fixed the indentation in some of the docs (Alice)
- Added Alice's r-b as appropriate
- Link to v6: https://lore.kernel.org/rust-for-linux/20250703-topics-tyr-request_irq-v6-0-74103bdc7c52@collabora.com/

Changes in v6:
- Fixed some typos in the docs (thanks, Dirk!)
- Reordered the arguments for the accessors in platform.rs (Danilo)
- Renamed handle_on_thread() to handle_threaded() (Danilo)
- Changed the documentation for Handler and ThreadedHandler to what
  Danilo suggested
- Link to v5: https://lore.kernel.org/r/20250627-topics-tyr-request_irq-v5-0-0545ee4dadf6@collabora.com

Changes in v5:

Thanks, Danilo {
  - Removed extra scope in the examples.
  - Renamed Registration::register() to Registration::new(),
  - Switched to try_pin_init! in Registration::new() (thanks for the
    code and the help, Boqun and Benno)
  - Renamed the trait functions to handle() and handle_on_thread().
  - Introduced IrqRequest with an unsafe pub(crate) constructor
  - Made both register() and the accessors that return IrqRequest public
    the idea is to allow both of these to work:
	// `irq` is an `irq::Registration`
	let irq = pdev.threaded_irq_by_name()?
  and
	// `req` is an `IrqRequest`.
	let req = pdev.irq_by_name()?;
	// `irq` is an `irq::Registration`
	let irq = irq::ThreadedRegistration::new(req)?;

  - Added another name in the byname variants. There's now one for the
    request part and the other one to register()
  - Reworked the examples in request.rs
  - Implemented the irq accessors in place for pci.rs
  - Split the platform accessor macros into two
}

- Added a rust helper for pci_irq_vectors if !CONFIG_PCI_MSI (thanks,
Intel 0day bot)
- Link to v4: https://lore.kernel.org/r/20250608-topics-tyr-request_irq-v4-0-81cb81fb8073@collabora.com

Changes in v4:

Thanks, Benno {
  - Split series into more patches (see patches 1-4)
  - Use cast() where possible
  - Merge pub use statements.
  - Add {Threaded}IrqReturn::into_inner() instead of #[repr(u32)]
  - Used AtomicU32 instead of SpinLock to add interior mutability to the
    handler's data. SpinLockIrq did not land yet.
  - Mention that `&self` is !Unpin and was initialized using pin_init in
    drop()
  - Fix the docs slightly
}

- Add {try_}synchronize_irq().
- Use Devres for the irq registration (see RegistrationInner). This idea
  was suggested by Danilo and Alice.
- Added PCI accessors (as asked by Joel Fernandez)
- Fix a major oversight: we were passing in a pointer to Registration
  in register_{threaded}_irq() but casting it to Handler/ThreadedHandler in
  the callbacks.
- Make register() pub(crate) so drivers can only retrieve registrations
  through device-specific accessors. This forbids drivers from trying to
  register an invalid irq.
- I think this will still go through a few rounds, so I'll defer the
  patch to update MAINTAINERS for now.

- Link to v3: https://lore.kernel.org/r/20250514-topics-tyr-request_irq-v3-0-d6fcc2591a88@collabora.com

Changes in v3:
- Rebased on driver-core-next
- Added patch to get the irq numbers from a platform device (thanks,
  Christian!)
- Split flags into its own file.
- Change iff to "if and only if"
- Implement PartialEq and Eq for Flags
- Fix some broken docs/markdown
- Reexport most things so users can elide ::request from the path
- Add a blanket implementation of ThreadedHandler and Handler for
  Arc/Box<T: Handler> that just forwards the call to the T. This lets us
  have Arc<Foo> and Box<Foo> as handlers if Foo: Handler.
- Rework the examples a bit.
- Remove "as _" casts in favor of "as u64" for flags. This is needed to
  cast the individual flags into u64.
- Use #[repr(u32)] for ThreadedIrqReturn and IrqReturn.
- Wrapped commit messages to < 75 characters

- Link to v2: https://lore.kernel.org/r/20250122163932.46697-1-daniel.almeida@collabora.com

Changes in v2:
- Added Co-developed-by tag to account for the work that Alice did in order to
figure out how to do this without Opaque<T> (Thanks!)
- Removed Opaque<T> in favor of plain T
- Fixed the examples
- Made sure that the invariants sections are the last entry in the docs
- Switched to slot.cast() where applicable,
- Mentioned in the safety comments that we require that T: Sync,
- Removed ThreadedFnReturn in favor of IrqReturn,
- Improved the commit message

Link to v1: https://lore.kernel.org/rust-for-linux/20241024-topic-panthor-rs-request_irq-v1-1-7cbc51c182ca@collabora.com/

---
Daniel Almeida (6):
      rust: irq: add irq module
      rust: irq: add flags module
      rust: irq: add support for non-threaded IRQs and handlers
      rust: irq: add support for threaded IRQs and handlers
      rust: platform: add irq accessors
      rust: pci: add irq accessors

 rust/bindings/bindings_helper.h |   1 +
 rust/helpers/helpers.c          |   1 +
 rust/helpers/irq.c              |   9 +
 rust/helpers/pci.c              |   8 +
 rust/kernel/irq.rs              |  22 ++
 rust/kernel/irq/flags.rs        | 124 ++++++++++
 rust/kernel/irq/request.rs      | 490 ++++++++++++++++++++++++++++++++++++++++
 rust/kernel/lib.rs              |   1 +
 rust/kernel/pci.rs              |  45 +++-
 rust/kernel/platform.rs         | 146 +++++++++++-
 10 files changed, 844 insertions(+), 3 deletions(-)
---
base-commit: 3964d07dd821efe9680e90c51c86661a98e60a0f
change-id: 20250712-topics-tyr-request_irq2-ae7ee9b85854

Best regards,
-- 
Daniel Almeida <daniel.almeida@collabora.com>