[PATCH 4/4] rust: io: add typedef for phys_addr_t

[Alice Ryhl <aliceryhl@google.com>]

The C typedef phys_addr_t is missing an analogue in Rust, meaning that
we end up using bindings::phys_addr_t or ResourceSize as a replacement
in various places throughout the kernel. Fix that by introducing a new
typedef on the Rust side. Place it next to the existing ResourceSize
typedef since they're quite related to each other.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/devres.rs      | 18 +++++++++++++++---
 rust/kernel/io.rs          | 20 +++++++++++++++++---
 rust/kernel/io/resource.rs |  9 ++++++---
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 10a6a17898541d4a0f01af41f68e3ab3d6bb0aca..e01e0d36702d38e9530a2fa4be884c935c6b5d0c 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -52,8 +52,20 @@ struct Inner<T: Send> {
 /// # Examples
 ///
 /// ```no_run
-/// # use kernel::{bindings, device::{Bound, Device}, devres::Devres, io::{Io, IoRaw}};
-/// # use core::ops::Deref;
+/// use kernel::{
+///     bindings,
+///     device::{
+///         Bound,
+///         Device,
+///     },
+///     devres::Devres,
+///     io::{
+///         Io,
+///         IoRaw,
+///         PhysAddr,
+///     },
+/// };
+/// use core::ops::Deref;
 ///
 /// // See also [`pci::Bar`] for a real example.
 /// struct IoMem<const SIZE: usize>(IoRaw<SIZE>);
@@ -66,7 +78,7 @@ struct Inner<T: Send> {
 ///     unsafe fn new(paddr: usize) -> Result<Self>{
 ///         // SAFETY: By the safety requirements of this function [`paddr`, `paddr` + `SIZE`) is
 ///         // valid for `ioremap`.
-///         let addr = unsafe { bindings::ioremap(paddr as bindings::phys_addr_t, SIZE) };
+///         let addr = unsafe { bindings::ioremap(paddr as PhysAddr, SIZE) };
 ///         if addr.is_null() {
 ///             return Err(ENOMEM);
 ///         }
diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index 6465ea94e85d689aef1f9031a4a5cc9505b9af6e..56a435eb14e3a1ce72dd58b88cbf296041f1703e 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -13,6 +13,12 @@
 
 pub use resource::Resource;
 
+/// Physical address type.
+///
+/// This is a type alias to either `u32` or `u64` depending on the config option
+/// `CONFIG_PHYS_ADDR_T_64BIT`, and it can be a u64 even on 32-bit architectures.
+pub type PhysAddr = bindings::phys_addr_t;
+
 /// Resource Size type.
 ///
 /// This is a type alias to either `u32` or `u64` depending on the config option
@@ -68,8 +74,16 @@ pub fn maxsize(&self) -> usize {
 /// # Examples
 ///
 /// ```no_run
-/// # use kernel::{bindings, ffi::c_void, io::{Io, IoRaw}};
-/// # use core::ops::Deref;
+/// use kernel::{
+///     bindings,
+///     ffi::c_void,
+///     io::{
+///         Io,
+///         IoRaw,
+///         PhysAddr,
+///     },
+/// };
+/// use core::ops::Deref;
 ///
 /// // See also [`pci::Bar`] for a real example.
 /// struct IoMem<const SIZE: usize>(IoRaw<SIZE>);
@@ -82,7 +96,7 @@ pub fn maxsize(&self) -> usize {
 ///     unsafe fn new(paddr: usize) -> Result<Self>{
 ///         // SAFETY: By the safety requirements of this function [`paddr`, `paddr` + `SIZE`) is
 ///         // valid for `ioremap`.
-///         let addr = unsafe { bindings::ioremap(paddr as bindings::phys_addr_t, SIZE) };
+///         let addr = unsafe { bindings::ioremap(paddr as PhysAddr, SIZE) };
 ///         if addr.is_null() {
 ///             return Err(ENOMEM);
 ///         }
diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs
index 7fed41fc20307fa7ce230da4b7841743631c965e..5d9d9f01d91c3b8b13e4837d4fb19a786d7720c8 100644
--- a/rust/kernel/io/resource.rs
+++ b/rust/kernel/io/resource.rs
@@ -12,7 +12,10 @@
 use crate::str::{CStr, CString};
 use crate::types::Opaque;
 
-pub use super::ResourceSize;
+pub use super::{
+    PhysAddr,
+    ResourceSize, \\
+};
 
 /// A region allocated from a parent [`Resource`].
 ///
@@ -93,7 +96,7 @@ impl Resource {
     /// the region, or a part of it, is already in use.
     pub fn request_region(
         &self,
-        start: ResourceSize,
+        start: PhysAddr,
         size: ResourceSize,
         name: CString,
         flags: Flags,
@@ -127,7 +130,7 @@ pub fn size(&self) -> ResourceSize {
     }
 
     /// Returns the start address of the resource.
-    pub fn start(&self) -> ResourceSize {
+    pub fn start(&self) -> PhysAddr {
         let inner = self.0.get();
         // SAFETY: Safe as per the invariants of `Resource`.
         unsafe { (*inner).start }

-- 
2.51.2.1026.g39e6a42477-goog