[PATCH 5/5] rust: pci: expose the allocated interrupt type

Add irq_type() on IrqVectorRegistration, wrapping the new pci_irq_type()
C function. A driver whose interrupt acknowledgment depends on the type
(MSI-X vs MSI vs INTx) queries it here rather than assuming which type
the PCI core selected.

Suggested-by: John Hubbard <[email protected]>
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Danilo Krummrich <[email protected]>
---
 rust/helpers/pci.c     |  5 +++++
 rust/kernel/pci/irq.rs | 17 +++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c
index e44905317d75..23b06becb448 100644
--- a/rust/helpers/pci.c
+++ b/rust/helpers/pci.c
@@ -24,6 +24,11 @@ __rust_helper bool rust_helper_dev_is_pci(const struct device *dev)
 	return dev_is_pci(dev);
 }
 
+__rust_helper unsigned int rust_helper_pci_irq_type(struct pci_dev *pdev)
+{
+	return pci_irq_type(pdev);
+}
+
 #ifndef CONFIG_PCI_MSI
 __rust_helper int rust_helper_pci_alloc_irq_vectors(struct pci_dev *dev,
 						    unsigned int min_vecs,
diff --git a/rust/kernel/pci/irq.rs b/rust/kernel/pci/irq.rs
index d69ab6435a80..618310e4535c 100644
--- a/rust/kernel/pci/irq.rs
+++ b/rust/kernel/pci/irq.rs
@@ -36,6 +36,16 @@ const fn as_raw(self) -> u32 {
             IrqType::MsiX => bindings::PCI_IRQ_MSIX,
         }
     }
+
+    /// Construct from raw value.
+    #[inline]
+    const fn from_raw(raw: u32) -> Self {
+        match raw {
+            bindings::PCI_IRQ_MSIX => IrqType::MsiX,
+            bindings::PCI_IRQ_MSI => IrqType::Msi,
+            _ => IrqType::Intx,
+        }
+    }
 }
 
 /// Set of IRQ types that can be used for PCI interrupt allocation.
@@ -99,6 +109,13 @@ pub fn vector_count(&self) -> usize {
         self.count.get()
     }
 
+    /// Returns the interrupt type the PCI core selected for this allocation.
+    #[inline]
+    pub fn irq_type(&self) -> IrqType {
+        // SAFETY: `self.dev.as_raw()` is a valid pointer to a `struct pci_dev`.
+        IrqType::from_raw(unsafe { bindings::pci_irq_type(self.dev.as_raw()) })
+    }
+
     /// Resolves the vector at `index` to an [`IrqRequest`].
     ///
     /// The returned [`IrqRequest`] borrows from this registration, ensuring the vector allocation
-- 
2.55.0