[PATCH v6 6/6] rust: pci: add irq accessors

Daniel Almeida
2025-07-03T19:31:27Z

These accessors can be used to retrieve a irq::Registration or a
irq::ThreadedRegistration from a pci device. Alternatively, drivers can
retrieve an IrqRequest from a bound PCI 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/helpers/pci.c | 8 ++++++++
rust/kernel/pci.rs | 45 +++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c
index cd0e6bf2cc4d9b37db3a717e7a8422b054f348ec..f372a32e8fd19730563ab51500e8c8764854ae47 100644
--- a/rust/helpers/pci.c
+++ b/rust/helpers/pci.c
@@ -21,3 +21,11 @@ bool rust_helper_dev_is_pci(const struct device *dev)
{
return dev_is_pci(dev);
}
+
+#ifndef CONFIG_PCI_MSI
+int rust_helper_pci_irq_vector(struct pci_dev *pdev, unsigned int nvec)
+{
+ return pci_irq_vector(pdev, nvec);
+}
+
+#endif
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index db0eb7eaf9b10c5316366ef16fe722a03044a517..60d37d6459518c79136535ce03c73a5a3097eda8 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -10,8 +10,8 @@
devres::Devres,
driver,
error::{to_result, Result},
- io::Io,
- io::IoRaw,
+ io::{Io, IoRaw},
+ irq::{self, request::IrqRequest},
str::CStr,
types::{ARef, ForeignOwnable, Opaque},
ThisModule,
@@ -413,6 +413,47 @@ pub fn iomap_region<'a>(
) -> impl PinInit<Devres<Bar>, Error> + 'a {
self.iomap_region_sized::<0>(bar, name)
}
+
+ /// Returns an [`IrqRequest`] for the IRQ vector 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 pci_dev`.
+ let irq = unsafe { crate::bindings::pci_irq_vector(self.as_raw(), index) };
+ if irq < 0 {
+ return Err(crate::error::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 a [`kernel::irq::Registration`] for the IRQ vector at the given
+ /// index.
+ pub fn irq_by_index<T: crate::irq::Handler + 'static>(
+ &self,
+ index: u32,
+ flags: irq::flags::Flags,
+ name: &'static CStr,
+ handler: T,
+ ) -> Result<impl PinInit<irq::Registration<T>, Error> + '_> {
+ let request = self.request_irq_by_index(index)?;
+
+ Ok(irq::Registration::<T>::new(request, flags, name, handler))
+ }
+
+ /// Returns a [`kernel::irq::ThreadedRegistration`] for the IRQ vector at
+ /// the given index.
+ pub fn threaded_irq_by_index<T: crate::irq::ThreadedHandler + 'static>(
+ &self,
+ index: u32,
+ flags: irq::flags::Flags,
+ name: &'static CStr,
+ handler: T,
+ ) -> Result<impl PinInit<irq::ThreadedRegistration<T>, Error> + '_> {
+ let request = self.request_irq_by_index(index)?;
+
+ Ok(irq::ThreadedRegistration::<T>::new(
+ request, flags, name, handler,
+ ))
+ }
}

impl Device<device::Core> {

--
2.50.0