[PATCH v5 1/8] rust: pci: add device name method

[Timur Tabi <ttabi@nvidia.com>]

Add a name() method to the `Device` type, which returns a CStr that
contains the device name, typically the BDF address for PCI devices.

Signed-off-by: Timur Tabi <ttabi@nvidia.com>
---
 rust/helpers/device.c |  5 +++++
 rust/kernel/device.rs | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/rust/helpers/device.c b/rust/helpers/device.c
index 9a4316bafedf..4609b62f6a06 100644
--- a/rust/helpers/device.c
+++ b/rust/helpers/device.c
@@ -25,3 +25,8 @@ void rust_helper_dev_set_drvdata(struct device *dev, void *data)
 {
 	dev_set_drvdata(dev, data);
 }
+
+const char *rust_helper_dev_name(const struct device *dev)
+{
+	return dev_name(dev);
+}
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index c79be2e2bfe3..636c522a8374 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -483,6 +483,22 @@ pub fn fwnode(&self) -> Option<&property::FwNode> {
         // defined as a `#[repr(transparent)]` wrapper around `fwnode_handle`.
         Some(unsafe { &*fwnode_handle.cast() })
     }
+
+    /// Returns the name of the device.
+    ///
+    /// This is the kobject name of the device, or its initial name if the kobject is not yet
+    /// available.
+    ///
+    /// For PCI devices, the name in the format "DDDD:BB:DD.F" where:
+    /// - DDDD is the PCI domain (4 hex digits)
+    /// - BB is the bus number (2 hex digits)
+    /// - DD is the device number (2 hex digits)
+    /// - F is the function number (1 hex digit)
+    pub fn name(&self) -> &CStr {
+        // SAFETY: By its type invariant `self.as_raw()` is a valid pointer to a `struct device`.
+        // The returned string is valid for the lifetime of the device.
+        unsafe { CStr::from_char_ptr(bindings::dev_name(self.as_raw())) }
+    }
 }
 
 // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic
-- 
2.52.0