rust: io: implement `Mmio` as view type

Implement `Mmio` as view type and convert `RelaxedMmio` to view type as
well. I/O implementations of `MmioOwned` are changed to delegate to the
`Mmio` view type.

All existing users of `MmioOwned` in the documentation which do not
actually reflect the owning semantics is converted.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Tested-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://patch.msgid.link/20260706-io_projection-v6-7-72cd5d055d54@garyguo.net
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

2 files changed, 18 insertions, 16 deletions

diff --git a/rust/kernel/io/poll.rs b/rust/kernel/io/poll.rs
index 79828a8006b5..d75f2fcf46f2 100644
--- a/rust/kernel/io/poll.rs
+++ b/rust/kernel/io/poll.rs
@@ -47,14 +47,15 @@ use crate::{
 /// ```no_run
 /// use kernel::io::{
 ///     Io,
-///     MmioOwned,
+///     Mmio,
+///     Region,
 ///     poll::read_poll_timeout, //
 /// };
 /// use kernel::time::Delta;
 ///
 /// const HW_READY: u16 = 0x01;
 ///
-/// fn wait_for_hardware<const SIZE: usize>(io: &MmioOwned<SIZE>) -> Result {
+/// fn wait_for_hardware<const SIZE: usize>(io: Mmio<'_, Region<SIZE>>) -> Result {
 ///     read_poll_timeout(
 ///         // The `op` closure reads the value of a specific status register.
 ///         || io.try_read16(0x1000),
@@ -134,14 +135,15 @@ where
 /// ```no_run
 /// use kernel::io::{
 ///     Io,
-///     MmioOwned,
+///     Mmio,
+///     Region,
 ///     poll::read_poll_timeout_atomic, //
 /// };
 /// use kernel::time::Delta;
 ///
 /// const HW_READY: u16 = 0x01;
 ///
-/// fn wait_for_hardware<const SIZE: usize>(io: &MmioOwned<SIZE>) -> Result {
+/// fn wait_for_hardware<const SIZE: usize>(io: Mmio<'_, Region<SIZE>>) -> Result {
 ///     read_poll_timeout_atomic(
 ///         // The `op` closure reads the value of a specific status register.
 ///         || io.try_read16(0x1000),
diff --git a/rust/kernel/io/register.rs b/rust/kernel/io/register.rs
index 43284d9fba96..80e638a892d7 100644
--- a/rust/kernel/io/register.rs
+++ b/rust/kernel/io/register.rs
@@ -58,7 +58,7 @@
 //!     },
 //!     num::Bounded,
 //! };
-//! # use kernel::io::MmioOwned;
+//! # use kernel::io::{Mmio, Region};
 //! # register! {
 //! #     pub BOOT_0(u32) @ 0x00000100 {
 //! #         15:8 vendor_id;
@@ -66,7 +66,7 @@
 //! #         3:0 minor_revision;
 //! #     }
 //! # }
-//! # fn test(io: &MmioOwned<0x1000>) {
+//! # fn test(io: Mmio<'_, Region<0x1000>>) {
 //! # fn obtain_vendor_id() -> u8 { 0xff }
 //!
 //! // Read from the register's defined offset (0x100).
@@ -446,7 +446,7 @@ where
 ///         Io,
 ///     },
 /// };
-/// # use kernel::io::MmioOwned;
+/// # use kernel::io::{Mmio, Region};
 ///
 /// register! {
 ///     FIXED_REG(u32) @ 0x100 {
@@ -455,7 +455,7 @@ where
 ///     }
 /// }
 ///
-/// # fn test(io: &MmioOwned<0x1000>) {
+/// # fn test(io: Mmio<'_, Region<0x1000>>) {
 /// let val = io.read(FIXED_REG);
 ///
 /// // Write from an already-existing value.
@@ -559,7 +559,7 @@ where
 ///         Io,
 ///     },
 /// };
-/// # use kernel::io::MmioOwned;
+/// # use kernel::io::{Mmio, Region};
 ///
 /// // Type used to identify the base.
 /// pub struct CpuCtlBase;
@@ -584,7 +584,7 @@ where
 ///     }
 /// }
 ///
-/// # fn test(io: MmioOwned<0x1000>) {
+/// # fn test(io: Mmio<'_, Region<0x1000>>) {
 /// // Read the status of `Cpu0`.
 /// let cpu0_started = io.read(CPU_CTL::of::<Cpu0>());
 ///
@@ -601,7 +601,7 @@ where
 ///     }
 /// }
 ///
-/// # fn test2(io: MmioOwned<0x1000>) {
+/// # fn test2(io: Mmio<'_, Region<0x1000>>) {
 /// // Start the aliased `CPU0`, leaving its other fields untouched.
 /// io.update(CPU_CTL_ALIAS::of::<Cpu0>(), |r| r.with_alias_start(true));
 /// # }
@@ -638,7 +638,7 @@ where
 ///         Io,
 ///     },
 /// };
-/// # use kernel::io::MmioOwned;
+/// # use kernel::io::{Mmio, Region};
 /// # fn get_scratch_idx() -> usize {
 /// #   0x15
 /// # }
@@ -651,7 +651,7 @@ where
 ///     }
 /// }
 ///
-/// # fn test(io: &MmioOwned<0x1000>)
+/// # fn test(io: Mmio<'_, Region<0x1000>>)
 /// #     -> Result<(), Error>{
 /// // Read scratch register 0, i.e. I/O address `0x80`.
 /// let scratch_0 = io.read(SCRATCH::at(0)).value();
@@ -724,7 +724,7 @@ where
 ///         Io,
 ///     },
 /// };
-/// # use kernel::io::MmioOwned;
+/// # use kernel::io::{Mmio, Region};
 /// # fn get_scratch_idx() -> usize {
 /// #   0x15
 /// # }
@@ -752,7 +752,7 @@ where
 ///     }
 /// }
 ///
-/// # fn test(io: &MmioOwned<0x1000>) -> Result<(), Error> {
+/// # fn test(io: Mmio<'_, Region<0x1000>>) -> Result<(), Error> {
 /// // Read scratch register 0 of CPU0.
 /// let scratch = io.read(CPU_SCRATCH::of::<Cpu0>().at(0));
 ///
@@ -794,7 +794,7 @@ where
 ///     }
 /// }
 ///
-/// # fn test2(io: &MmioOwned<0x1000>) -> Result<(), Error> {
+/// # fn test2(io: Mmio<'_, Region<0x1000>>) -> Result<(), Error> {
 /// let cpu0_status = io.read(CPU_FIRMWARE_STATUS::of::<Cpu0>()).status();
 /// # Ok(())
 /// # }