rust: io: remove `MmioOwned`

`Io` trait is now very easy to implement. Thus, implement it on `Bar` and
`IoMem` directly and remove the `MmioOwned` struct.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Suggested-by: Danilo Krummrich <dakr@kernel.org>
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Generic.20I.2FO.20backends/near/571198078
Link: https://patch.msgid.link/20260706-io_projection-v6-11-72cd5d055d54@garyguo.net
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 15 insertions, 11 deletions

diff --git a/rust/kernel/io/mem.rs b/rust/kernel/io/mem.rs
index 8f6c257c5b8e..d9b3189d09b4 100644
--- a/rust/kernel/io/mem.rs
+++ b/rust/kernel/io/mem.rs
@@ -2,8 +2,6 @@
 
 //! Generic memory-mapped IO.
 
-use core::ops::Deref;
-
 use crate::{
     device::{
         Bound,
@@ -16,7 +14,9 @@ use crate::{
             Region,
             Resource, //
         },
-        MmioOwned,
+        Io,
+        Mmio,
+        MmioBackend,
         MmioRaw, //
     },
     prelude::*,
@@ -210,11 +210,13 @@ impl<'a, const SIZE: usize> ExclusiveIoMem<'a, SIZE> {
     }
 }
 
-impl<const SIZE: usize> Deref for ExclusiveIoMem<'_, SIZE> {
-    type Target = MmioOwned<SIZE>;
+impl<'a, const SIZE: usize> Io<'a> for &'a ExclusiveIoMem<'_, SIZE> {
+    type Backend = MmioBackend;
+    type Target = super::Region<SIZE>;
 
-    fn deref(&self) -> &Self::Target {
-        &self.iomem
+    #[inline]
+    fn as_view(self) -> Mmio<'a, Self::Target> {
+        self.iomem.as_view()
     }
 }
 
@@ -290,11 +292,13 @@ impl<const SIZE: usize> Drop for IoMem<'_, SIZE> {
     }
 }
 
-impl<const SIZE: usize> Deref for IoMem<'_, SIZE> {
-    type Target = MmioOwned<SIZE>;
+impl<'a, const SIZE: usize> Io<'a> for &'a IoMem<'_, SIZE> {
+    type Backend = MmioBackend;
+    type Target = super::Region<SIZE>;
 
-    fn deref(&self) -> &Self::Target {
+    #[inline]
+    fn as_view(self) -> Mmio<'a, Self::Target> {
         // SAFETY: Safe as by the invariant of `IoMem`.
-        unsafe { MmioOwned::from_raw(&self.io) }
+        unsafe { Mmio::from_raw(self.io) }
     }
 }