[PATCH v6 5/6] rust: platform: add irq accessors

Daniel Almeida
2025-07-03T19:31:18Z

These accessors can be used to retrieve a irq::Registration and
irq::ThreadedRegistration from a platform device by
index or name. Alternatively, drivers can retrieve an IrqRequest from a
bound platform device for later use.

These accessors ensure that only valid IRQ lines can ever be registered.

Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
---
rust/kernel/platform.rs | 143 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 142 insertions(+), 1 deletion(-)

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 5b21fa517e55348582622ec10471918919502959..bfcb4962dda7ec420dc86dfa04311be0462ad9f2 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -5,8 +5,11 @@
//! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h)

use crate::{
- bindings, container_of, device, driver,
+ bindings, container_of,
+ device::{self, Bound},
+ driver,
error::{to_result, Result},
+ irq::{self, request::IrqRequest},
of,
prelude::*,
str::CStr,
@@ -190,6 +193,144 @@ fn as_raw(&self) -> *mut bindings::platform_device {
}
}

+macro_rules! define_irq_accessor_by_index {
+ ($(#[$meta:meta])* $fn_name:ident, $request_fn:ident, $reg_type:ident, $handler_trait:ident) => {
+ $(#[$meta])*
+ pub fn $fn_name<T: irq::$handler_trait + 'static>(
+ &self,
+ flags: irq::flags::Flags,
+ index: u32,
+ name: &'static CStr,
+ handler: T,
+ ) -> Result<impl PinInit<irq::$reg_type<T>, Error> + '_> {
+ let request = self.$request_fn(index)?;
+
+ Ok(irq::$reg_type::<T>::new(
+ request,
+ flags,
+ name,
+ handler,
+ ))
+ }
+ };
+}
+
+macro_rules! define_irq_accessor_by_name {
+ ($(#[$meta:meta])* $fn_name:ident, $request_fn:ident, $reg_type:ident, $handler_trait:ident) => {
+ $(#[$meta])*
+ pub fn $fn_name<T: irq::$handler_trait + 'static>(
+ &self,
+ flags: irq::flags::Flags,
+ irq_name: &'static CStr,
+ name: &'static CStr,
+ handler: T,
+ ) -> Result<impl PinInit<irq::$reg_type<T>, Error> + '_> {
+ let request = self.$request_fn(irq_name)?;
+
+ Ok(irq::$reg_type::<T>::new(
+ request,
+ flags,
+ name,
+ handler,
+ ))
+ }
+ };
+}
+
+impl Device<Bound> {
+ /// Returns an [`IrqRequest`] for the IRQ at the given index, if any.
+ pub fn request_irq_by_index(&self, index: u32) -> Result<IrqRequest<'_>> {
+ // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`.
+ let irq = unsafe { bindings::platform_get_irq(self.as_raw(), index) };
+
+ if irq < 0 {
+ return Err(Error::from_errno(irq));
+ }
+
+ // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`.
+ Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) })
+ }
+
+ /// Returns an [`IrqRequest`] for the IRQ at the given index, but does not print an error if the IRQ cannot be obtained.
+ pub fn request_optional_irq_by_index(&self, index: u32) -> Result<IrqRequest<'_>> {
+ // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`.
+ let irq = unsafe { bindings::platform_get_irq_optional(self.as_raw(), index) };
+
+ if irq < 0 {
+ return Err(Error::from_errno(irq));
+ }
+
+ // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`.
+ Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) })
+ }
+
+ /// Returns an [`IrqRequest`] for the IRQ with the given name, if any.
+ pub fn request_irq_by_name(&self, name: &'static CStr) -> Result<IrqRequest<'_>> {
+ // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`.
+ let irq = unsafe { bindings::platform_get_irq_byname(self.as_raw(), name.as_char_ptr()) };
+
+ if irq < 0 {
+ return Err(Error::from_errno(irq));
+ }
+
+ // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`.
+ Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) })
+ }
+
+ /// Returns an [`IrqRequest`] for the IRQ with the given name, but does not print an error if the IRQ cannot be obtained.
+ pub fn request_optional_irq_by_name(&self, name: &'static CStr) -> Result<IrqRequest<'_>> {
+ // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`.
+ let irq = unsafe {
+ bindings::platform_get_irq_byname_optional(self.as_raw(), name.as_char_ptr())
+ };
+
+ if irq < 0 {
+ return Err(Error::from_errno(irq));
+ }
+
+ // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`.
+ Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) })
+ }
+
+ define_irq_accessor_by_index!(
+ /// Returns a [`irq::Registration`] for the IRQ at the given index.
+ irq_by_index, request_irq_by_index, Registration, Handler
+ );
+ define_irq_accessor_by_name!(
+ /// Returns a [`irq::Registration`] for the IRQ with the given name.
+ irq_by_name, request_irq_by_name, Registration, Handler
+ );
+ define_irq_accessor_by_index!(
+ /// Does the same as [`Self::irq_by_index`], except that it does not
+ /// print an error message if the IRQ cannot be obtained.
+ optional_irq_by_index, request_optional_irq_by_index, Registration, Handler
+ );
+ define_irq_accessor_by_name!(
+ /// Does the same as [`Self::irq_by_name`], except that it does not
+ /// print an error message if the IRQ cannot be obtained.
+ optional_irq_by_name, request_optional_irq_by_name, Registration, Handler
+ );
+
+ define_irq_accessor_by_index!(
+ /// Returns a [`irq::ThreadedRegistration`] for the IRQ at the given index.
+ threaded_irq_by_index, request_irq_by_index, ThreadedRegistration, ThreadedHandler
+ );
+ define_irq_accessor_by_name!(
+ /// Returns a [`irq::ThreadedRegistration`] for the IRQ with the given name.
+ threaded_irq_by_name, request_irq_by_name, ThreadedRegistration, ThreadedHandler
+ );
+ define_irq_accessor_by_index!(
+ /// Does the same as [`Self::threaded_irq_by_index`], except that it
+ /// does not print an error message if the IRQ cannot be obtained.
+ optional_threaded_irq_by_index, request_optional_irq_by_index, ThreadedRegistration, ThreadedHandler
+ );
+ define_irq_accessor_by_name!(
+ /// Does the same as [`Self::threaded_irq_by_name`], except that it
+ /// does not print an error message if the IRQ cannot be obtained.
+ optional_threaded_irq_by_name, request_optional_irq_by_name, ThreadedRegistration, ThreadedHandler
+ );
+}
+
// SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic
// argument.
kernel::impl_device_context_deref!(unsafe { Device });

--
2.50.0