[PATCH v8 2/5] rust: io: factor common I/O helpers into Io trait

Zhi Wang
2026-01-13T09:23:50Z

The previous Io<SIZE> type combined both the generic I/O access helpers
and MMIO implementation details in a single struct.

To establish a cleaner layering between the I/O interface and its concrete
backends, paving the way for supporting additional I/O mechanisms in the
future, Io<SIZE> need to be factored.

Factor the common helpers into new {Io, Io64} traits, and move the
MMIO-specific logic into a dedicated Mmio<SIZE> type implementing that
trait. Rename the IoRaw to MmioRaw and update the bus MMIO implementations
to use MmioRaw.

No functional change intended.

Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
drivers/gpu/nova-core/gsp/sequencer.rs | 5 +-
drivers/gpu/nova-core/regs/macros.rs | 90 ++++----
drivers/gpu/nova-core/vbios.rs | 1 +
rust/kernel/devres.rs | 14 +-
rust/kernel/io.rs | 271 ++++++++++++++++++-------
rust/kernel/io/mem.rs | 16 +-
rust/kernel/io/poll.rs | 8 +-
rust/kernel/pci/io.rs | 12 +-
samples/rust/rust_driver_pci.rs | 2 +
9 files changed, 288 insertions(+), 131 deletions(-)

diff --git a/drivers/gpu/nova-core/gsp/sequencer.rs b/drivers/gpu/nova-core/gsp/sequencer.rs
index 2d0369c49092..862cf7f27143 100644
--- a/drivers/gpu/nova-core/gsp/sequencer.rs
+++ b/drivers/gpu/nova-core/gsp/sequencer.rs
@@ -12,7 +12,10 @@

use kernel::{
device,
- io::poll::read_poll_timeout,
+ io::{
+ poll::read_poll_timeout,
+ Io, //
+ },
prelude::*,
time::{
delay::fsleep,
diff --git a/drivers/gpu/nova-core/regs/macros.rs b/drivers/gpu/nova-core/regs/macros.rs
index fd1a815fa57d..6c7d164937a0 100644
--- a/drivers/gpu/nova-core/regs/macros.rs
+++ b/drivers/gpu/nova-core/regs/macros.rs
@@ -369,16 +369,18 @@ impl $name {

/// Read the register from its address in `io`.
#[inline(always)]
- pub(crate) fn read<const SIZE: usize, T>(io: &T) -> Self where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ pub(crate) fn read<T, I>(io: &T) -> Self where
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
{
Self(io.read32($offset))
}

/// Write the value contained in `self` to the register address in `io`.
#[inline(always)]
- pub(crate) fn write<const SIZE: usize, T>(self, io: &T) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ pub(crate) fn write<T, I>(self, io: &T) where
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
{
io.write32(self.0, $offset)
}
@@ -386,11 +388,12 @@ pub(crate) fn write<const SIZE: usize, T>(self, io: &T) where
/// Read the register from its address in `io` and run `f` on its value to obtain a new
/// value to write back.
#[inline(always)]
- pub(crate) fn update<const SIZE: usize, T, F>(
+ pub(crate) fn update<T, I, F>(
io: &T,
f: F,
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
F: ::core::ops::FnOnce(Self) -> Self,
{
let reg = f(Self::read(io));
@@ -408,12 +411,13 @@ impl $name {
/// Read the register from `io`, using the base address provided by `base` and adding
/// the register's offset to it.
#[inline(always)]
- pub(crate) fn read<const SIZE: usize, T, B>(
+ pub(crate) fn read<T, I, B>(
io: &T,
#[allow(unused_variables)]
base: &B,
) -> Self where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
{
const OFFSET: usize = $name::OFFSET;
@@ -428,13 +432,14 @@ pub(crate) fn read<const SIZE: usize, T, B>(
/// Write the value contained in `self` to `io`, using the base address provided by
/// `base` and adding the register's offset to it.
#[inline(always)]
- pub(crate) fn write<const SIZE: usize, T, B>(
+ pub(crate) fn write<T, I, B>(
self,
io: &T,
#[allow(unused_variables)]
base: &B,
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
{
const OFFSET: usize = $name::OFFSET;
@@ -449,12 +454,13 @@ pub(crate) fn write<const SIZE: usize, T, B>(
/// the register's offset to it, then run `f` on its value to obtain a new value to
/// write back.
#[inline(always)]
- pub(crate) fn update<const SIZE: usize, T, B, F>(
+ pub(crate) fn update<T, I, B, F>(
io: &T,
base: &B,
f: F,
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
F: ::core::ops::FnOnce(Self) -> Self,
{
@@ -474,11 +480,12 @@ impl $name {

/// Read the array register at index `idx` from its address in `io`.
#[inline(always)]
- pub(crate) fn read<const SIZE: usize, T>(
+ pub(crate) fn read<T, I>(
io: &T,
idx: usize,
) -> Self where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
{
build_assert!(idx < Self::SIZE);

@@ -490,12 +497,13 @@ pub(crate) fn read<const SIZE: usize, T>(

/// Write the value contained in `self` to the array register with index `idx` in `io`.
#[inline(always)]
- pub(crate) fn write<const SIZE: usize, T>(
+ pub(crate) fn write<T, I>(
self,
io: &T,
idx: usize
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
{
build_assert!(idx < Self::SIZE);

@@ -507,12 +515,13 @@ pub(crate) fn write<const SIZE: usize, T>(
/// Read the array register at index `idx` in `io` and run `f` on its value to obtain a
/// new value to write back.
#[inline(always)]
- pub(crate) fn update<const SIZE: usize, T, F>(
+ pub(crate) fn update<T, I, F>(
io: &T,
idx: usize,
f: F,
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
F: ::core::ops::FnOnce(Self) -> Self,
{
let reg = f(Self::read(io, idx));
@@ -524,11 +533,12 @@ pub(crate) fn update<const SIZE: usize, T, F>(
/// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the
/// access was out-of-bounds.
#[inline(always)]
- pub(crate) fn try_read<const SIZE: usize, T>(
+ pub(crate) fn try_read<T, I>(
io: &T,
idx: usize,
) -> ::kernel::error::Result<Self> where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
{
if idx < Self::SIZE {
Ok(Self::read(io, idx))
@@ -542,12 +552,13 @@ pub(crate) fn try_read<const SIZE: usize, T>(
/// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the
/// access was out-of-bounds.
#[inline(always)]
- pub(crate) fn try_write<const SIZE: usize, T>(
+ pub(crate) fn try_write<T, I>(
self,
io: &T,
idx: usize,
) -> ::kernel::error::Result where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
{
if idx < Self::SIZE {
Ok(self.write(io, idx))
@@ -562,12 +573,13 @@ pub(crate) fn try_write<const SIZE: usize, T>(
/// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the
/// access was out-of-bounds.
#[inline(always)]
- pub(crate) fn try_update<const SIZE: usize, T, F>(
+ pub(crate) fn try_update<T, I, F>(
io: &T,
idx: usize,
f: F,
) -> ::kernel::error::Result where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
F: ::core::ops::FnOnce(Self) -> Self,
{
if idx < Self::SIZE {
@@ -593,13 +605,14 @@ impl $name {
/// Read the array register at index `idx` from `io`, using the base address provided
/// by `base` and adding the register's offset to it.
#[inline(always)]
- pub(crate) fn read<const SIZE: usize, T, B>(
+ pub(crate) fn read<T, I, B>(
io: &T,
#[allow(unused_variables)]
base: &B,
idx: usize,
) -> Self where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
{
build_assert!(idx < Self::SIZE);
@@ -614,14 +627,15 @@ pub(crate) fn read<const SIZE: usize, T, B>(
/// Write the value contained in `self` to `io`, using the base address provided by
/// `base` and adding the offset of array register `idx` to it.
#[inline(always)]
- pub(crate) fn write<const SIZE: usize, T, B>(
+ pub(crate) fn write<T, I, B>(
self,
io: &T,
#[allow(unused_variables)]
base: &B,
idx: usize
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
{
build_assert!(idx < Self::SIZE);
@@ -636,13 +650,14 @@ pub(crate) fn write<const SIZE: usize, T, B>(
/// by `base` and adding the register's offset to it, then run `f` on its value to
/// obtain a new value to write back.
#[inline(always)]
- pub(crate) fn update<const SIZE: usize, T, B, F>(
+ pub(crate) fn update<T, I, B, F>(
io: &T,
base: &B,
idx: usize,
f: F,
) where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
F: ::core::ops::FnOnce(Self) -> Self,
{
@@ -656,12 +671,13 @@ pub(crate) fn update<const SIZE: usize, T, B, F>(
/// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the
/// access was out-of-bounds.
#[inline(always)]
- pub(crate) fn try_read<const SIZE: usize, T, B>(
+ pub(crate) fn try_read<T, I, B>(
io: &T,
base: &B,
idx: usize,
) -> ::kernel::error::Result<Self> where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
{
if idx < Self::SIZE {
@@ -677,13 +693,14 @@ pub(crate) fn try_read<const SIZE: usize, T, B>(
/// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the
/// access was out-of-bounds.
#[inline(always)]
- pub(crate) fn try_write<const SIZE: usize, T, B>(
+ pub(crate) fn try_write<T, I, B>(
self,
io: &T,
base: &B,
idx: usize,
) -> ::kernel::error::Result where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
{
if idx < Self::SIZE {
@@ -700,13 +717,14 @@ pub(crate) fn try_write<const SIZE: usize, T, B>(
/// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the
/// access was out-of-bounds.
#[inline(always)]
- pub(crate) fn try_update<const SIZE: usize, T, B, F>(
+ pub(crate) fn try_update<T, I, B, F>(
io: &T,
base: &B,
idx: usize,
f: F,
) -> ::kernel::error::Result where
- T: ::core::ops::Deref<Target = ::kernel::io::Io<SIZE>>,
+ T: ::core::ops::Deref<Target = I>,
+ I: ::kernel::io::IoKnownSize,
B: crate::regs::macros::RegisterBase<$base>,
F: ::core::ops::FnOnce(Self) -> Self,
{
diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index abf423560ff4..fe33b519e4d8 100644
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -6,6 +6,7 @@

use kernel::{
device,
+ io::Io,
prelude::*,
ptr::{
Alignable,
diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 43089511bf76..dfaddac2af59 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -73,15 +73,16 @@ struct Inner<T: Send> {
/// },
/// devres::Devres,
/// io::{
-/// Io,
-/// IoRaw,
+/// IoKnownSize,
+/// Mmio,
+/// MmioRaw,
/// PhysAddr,
/// },
/// };
/// use core::ops::Deref;
///
/// // See also [`pci::Bar`] for a real example.
-/// struct IoMem<const SIZE: usize>(IoRaw<SIZE>);
+/// struct IoMem<const SIZE: usize>(MmioRaw<SIZE>);
///
/// impl<const SIZE: usize> IoMem<SIZE> {
/// /// # Safety
@@ -96,7 +97,7 @@ struct Inner<T: Send> {
/// return Err(ENOMEM);
/// }
///
-/// Ok(IoMem(IoRaw::new(addr as usize, SIZE)?))
+/// Ok(IoMem(MmioRaw::new(addr as usize, SIZE)?))
/// }
/// }
///
@@ -108,11 +109,11 @@ struct Inner<T: Send> {
/// }
///
/// impl<const SIZE: usize> Deref for IoMem<SIZE> {
-/// type Target = Io<SIZE>;
+/// type Target = Mmio<SIZE>;
///
/// fn deref(&self) -> &Self::Target {
/// // SAFETY: The memory range stored in `self` has been properly mapped in `Self::new`.
-/// unsafe { Io::from_raw(&self.0) }
+/// unsafe { Mmio::from_raw(&self.0) }
/// }
/// }
/// # fn no_run(dev: &Device<Bound>) -> Result<(), Error> {
@@ -258,6 +259,7 @@ pub fn device(&self) -> &Device {
/// use kernel::{
/// device::Core,
/// devres::Devres,
+ /// io::IoKnownSize,
/// pci, //
/// };
///
diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index a97eb44a9a87..6e7f0d48ba3e 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -32,16 +32,16 @@
/// By itself, the existence of an instance of this structure does not provide any guarantees that
/// the represented MMIO region does exist or is properly mapped.
///
-/// Instead, the bus specific MMIO implementation must convert this raw representation into an `Io`
-/// instance providing the actual memory accessors. Only by the conversion into an `Io` structure
-/// any guarantees are given.
-pub struct IoRaw<const SIZE: usize = 0> {
+/// Instead, the bus specific MMIO implementation must convert this raw representation into an
+/// `Mmio` instance providing the actual memory accessors. Only by the conversion into an `Mmio`
+/// structure any guarantees are given.
+pub struct MmioRaw<const SIZE: usize = 0> {
addr: usize,
maxsize: usize,
}

-impl<const SIZE: usize> IoRaw<SIZE> {
- /// Returns a new `IoRaw` instance on success, an error otherwise.
+impl<const SIZE: usize> MmioRaw<SIZE> {
+ /// Returns a new `MmioRaw` instance on success, an error otherwise.
pub fn new(addr: usize, maxsize: usize) -> Result<Self> {
if maxsize < SIZE {
return Err(EINVAL);
@@ -81,14 +81,16 @@ pub fn maxsize(&self) -> usize {
/// ffi::c_void,
/// io::{
/// Io,
-/// IoRaw,
+/// IoKnownSize,
+/// Mmio,
+/// MmioRaw,
/// PhysAddr,
/// },
/// };
/// use core::ops::Deref;
///
/// // See also `pci::Bar` for a real example.
-/// struct IoMem<const SIZE: usize>(IoRaw<SIZE>);
+/// struct IoMem<const SIZE: usize>(MmioRaw<SIZE>);
///
/// impl<const SIZE: usize> IoMem<SIZE> {
/// /// # Safety
@@ -103,7 +105,7 @@ pub fn maxsize(&self) -> usize {
/// return Err(ENOMEM);
/// }
///
-/// Ok(IoMem(IoRaw::new(addr as usize, SIZE)?))
+/// Ok(IoMem(MmioRaw::new(addr as usize, SIZE)?))
/// }
/// }
///
@@ -115,11 +117,11 @@ pub fn maxsize(&self) -> usize {
/// }
///
/// impl<const SIZE: usize> Deref for IoMem<SIZE> {
-/// type Target = Io<SIZE>;
+/// type Target = Mmio<SIZE>;
///
/// fn deref(&self) -> &Self::Target {
/// // SAFETY: The memory range stored in `self` has been properly mapped in `Self::new`.
-/// unsafe { Io::from_raw(&self.0) }
+/// unsafe { Mmio::from_raw(&self.0) }
/// }
/// }
///
@@ -133,29 +135,31 @@ pub fn maxsize(&self) -> usize {
/// # }
/// ```
#[repr(transparent)]
-pub struct Io<const SIZE: usize = 0>(IoRaw<SIZE>);
+pub struct Mmio<const SIZE: usize = 0>(MmioRaw<SIZE>);

macro_rules! define_read {
- ($(#[$attr:meta])* $name:ident, $try_name:ident, $c_fn:ident -> $type_name:ty) => {
+ (infallible, $(#[$attr:meta])* $vis:vis $name:ident, $c_fn:ident -> $type_name:ty) => {
/// Read IO data from a given offset known at compile time.
///
/// Bound checks are performed on compile time, hence if the offset is not known at compile
/// time, the build will fail.
$(#[$attr])*
#[inline]
- pub fn $name(&self, offset: usize) -> $type_name {
+ $vis fn $name(&self, offset: usize) -> $type_name {
let addr = self.io_addr_assert::<$type_name>(offset);

// SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
unsafe { bindings::$c_fn(addr as *const c_void) }
}
+ };

+ (fallible, $(#[$attr:meta])* $vis:vis $try_name:ident, $c_fn:ident -> $type_name:ty) => {
/// Read IO data from a given offset.
///
/// Bound checks are performed on runtime, it fails if the offset (plus the type size) is
/// out of bounds.
$(#[$attr])*
- pub fn $try_name(&self, offset: usize) -> Result<$type_name> {
+ $vis fn $try_name(&self, offset: usize) -> Result<$type_name> {
let addr = self.io_addr::<$type_name>(offset)?;

// SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
@@ -165,26 +169,28 @@ pub fn $try_name(&self, offset: usize) -> Result<$type_name> {
}

macro_rules! define_write {
- ($(#[$attr:meta])* $name:ident, $try_name:ident, $c_fn:ident <- $type_name:ty) => {
+ (infallible, $(#[$attr:meta])* $vis:vis $name:ident, $c_fn:ident <- $type_name:ty) => {
/// Write IO data from a given offset known at compile time.
///
/// Bound checks are performed on compile time, hence if the offset is not known at compile
/// time, the build will fail.
$(#[$attr])*
#[inline]
- pub fn $name(&self, value: $type_name, offset: usize) {
+ $vis fn $name(&self, value: $type_name, offset: usize) {
let addr = self.io_addr_assert::<$type_name>(offset);

// SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
unsafe { bindings::$c_fn(value, addr as *mut c_void) }
}
+ };

+ (fallible, $(#[$attr:meta])* $vis:vis $try_name:ident, $c_fn:ident <- $type_name:ty) => {
/// Write IO data from a given offset.
///
/// Bound checks are performed on runtime, it fails if the offset (plus the type size) is
/// out of bounds.
$(#[$attr])*
- pub fn $try_name(&self, value: $type_name, offset: usize) -> Result {
+ $vis fn $try_name(&self, value: $type_name, offset: usize) -> Result {
let addr = self.io_addr::<$type_name>(offset)?;

// SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
@@ -194,43 +200,38 @@ pub fn $try_name(&self, value: $type_name, offset: usize) -> Result {
};
}

-impl<const SIZE: usize> Io<SIZE> {
- /// Converts an `IoRaw` into an `Io` instance, providing the accessors to the MMIO mapping.
- ///
- /// # Safety
- ///
- /// Callers must ensure that `addr` is the start of a valid I/O mapped memory region of size
- /// `maxsize`.
- pub unsafe fn from_raw(raw: &IoRaw<SIZE>) -> &Self {
- // SAFETY: `Io` is a transparent wrapper around `IoRaw`.
- unsafe { &*core::ptr::from_ref(raw).cast() }
+/// Checks whether an access of type `U` at the given `offset`
+/// is valid within this region.
+#[inline]
+const fn offset_valid(offset: usize, size: usize) -> bool {
+ let type_size = core::mem::size_of::();
+ if let Some(end) = offset.checked_add(type_size) {
+ end <= size && offset % type_size == 0
+ } else {
+ false
}
+}
+
+/// Represents a region of I/O space of a fixed size.
+///
+/// Provides common helpers for offset validation and address
+/// calculation on top of a base address and maximum size.
+///
+pub trait IoBase {
+ /// Minimum usable size of this region.
+ const MIN_SIZE: usize;

/// Returns the base address of this mapping.
- #[inline]
- pub fn addr(&self) -> usize {
- self.0.addr()
- }
+ fn addr(&self) -> usize;

/// Returns the maximum size of this mapping.
- #[inline]
- pub fn maxsize(&self) -> usize {
- self.0.maxsize()
- }
-
- #[inline]
- const fn offset_valid(offset: usize, size: usize) -> bool {
- let type_size = core::mem::size_of::();
- if let Some(end) = offset.checked_add(type_size) {
- end <= size && offset % type_size == 0
- } else {
- false
- }
- }
+ fn maxsize(&self) -> usize;

+ /// Returns the absolute I/O address for a given `offset`,
+ /// performing runtime bound checks.
#[inline]
fn io_addr(&self, offset: usize) -> Result<usize> {
- if !Self::offset_valid::(offset, self.maxsize()) {
+ if !offset_valid::(offset, self.maxsize()) {
return Err(EINVAL);
}

@@ -239,50 +240,180 @@ fn io_addr(&self, offset: usize) -> Result<usize> {
self.addr().checked_add(offset).ok_or(EINVAL)
}

+ /// Returns the absolute I/O address for a given `offset`,
+ /// performing compile-time bound checks.
#[inline]
fn io_addr_assert(&self, offset: usize) -> usize {
- build_assert!(Self::offset_valid::(offset, SIZE));
+ build_assert!(offset_valid::(offset, Self::MIN_SIZE));

self.addr() + offset
}
+}
+
+/// Types implementing this trait (e.g. MMIO BARs or PCI config
+/// regions) can share the same KnownSize accessors.
+pub trait IoKnownSize: IoBase {
+ /// Infallible 8-bit read with compile-time bounds check.
+ fn read8(&self, offset: usize) -> u8;
+
+ /// Infallible 16-bit read with compile-time bounds check.
+ fn read16(&self, offset: usize) -> u16;
+
+ /// Infallible 32-bit read with compile-time bounds check.
+ fn read32(&self, offset: usize) -> u32;
+
+ /// Infallible 8-bit write with compile-time bounds check.
+ fn write8(&self, value: u8, offset: usize);
+
+ /// Infallible 16-bit write with compile-time bounds check.
+ fn write16(&self, value: u16, offset: usize);
+
+ /// Infallible 32-bit write with compile-time bounds check.
+ fn write32(&self, value: u32, offset: usize);
+}
+
+/// Types implementing this trait (e.g. MMIO BARs or PCI config
+/// regions) can share the same Io accessors.
+pub trait Io: IoBase {
+ /// Fallible 8-bit read with runtime bounds check.
+ fn try_read8(&self, offset: usize) -> Result<u8>;
+
+ /// Fallible 16-bit read with runtime bounds check.
+ fn try_read16(&self, offset: usize) -> Result<u16>;
+
+ /// Fallible 32-bit read with runtime bounds check.
+ fn try_read32(&self, offset: usize) -> Result<u32>;
+
+ /// Fallible 8-bit write with runtime bounds check.
+ fn try_write8(&self, value: u8, offset: usize) -> Result;
+
+ /// Fallible 16-bit write with runtime bounds check.
+ fn try_write16(&self, value: u16, offset: usize) -> Result;
+
+ /// Fallible 32-bit write with runtime bounds check.
+ fn try_write32(&self, value: u32, offset: usize) -> Result;
+}
+
+/// Represents a region of I/O space of a fixed size with 64-bit accessors.
+/// Types implementing this trait can share the same Infallible accessors.
+#[cfg(CONFIG_64BIT)]
+pub trait IoKnownSize64: IoKnownSize {
+ /// Infallible 64-bit read with compile-time bounds check.
+ fn read64(&self, offset: usize) -> u64;

- define_read!(read8, try_read8, readb -> u8);
- define_read!(read16, try_read16, readw -> u16);
- define_read!(read32, try_read32, readl -> u32);
+ /// Infallible 64-bit write with compile-time bounds check.
+ fn write64(&self, value: u64, offset: usize);
+}
+
+/// Types implementing this trait can share the same Fallible accessors.
+#[cfg(CONFIG_64BIT)]
+pub trait Io64: Io {
+ /// Fallible 64-bit read with runtime bounds check.
+ fn try_read64(&self, offset: usize) -> Result<u64>;
+
+ /// Fallible 64-bit write with runtime bounds check.
+ fn try_write64(&self, value: u64, offset: usize) -> Result;
+}
+
+impl<const SIZE: usize> IoBase for Mmio<SIZE> {
+ const MIN_SIZE: usize = SIZE;
+
+ /// Returns the base address of this mapping.
+ #[inline]
+ fn addr(&self) -> usize {
+ self.0.addr()
+ }
+
+ /// Returns the maximum size of this mapping.
+ #[inline]
+ fn maxsize(&self) -> usize {
+ self.0.maxsize()
+ }
+}
+
+impl<const SIZE: usize> IoKnownSize for Mmio<SIZE> {
+ define_read!(infallible, read8, readb -> u8);
+ define_read!(infallible, read16, readw -> u16);
+ define_read!(infallible, read32, readl -> u32);
+
+ define_write!(infallible, write8, writeb <- u8);
+ define_write!(infallible, write16, writew <- u16);
+ define_write!(infallible, write32, writel <- u32);
+}
+
+impl<const SIZE: usize> Io for Mmio<SIZE> {
+ define_read!(fallible, try_read8, readb -> u8);
+ define_read!(fallible, try_read16, readw -> u16);
+ define_read!(fallible, try_read32, readl -> u32);
+
+ define_write!(fallible, try_write8, writeb <- u8);
+ define_write!(fallible, try_write16, writew <- u16);
+ define_write!(fallible, try_write32, writel <- u32);
+}
+
+#[cfg(CONFIG_64BIT)]
+impl<const SIZE: usize> IoKnownSize64 for Mmio<SIZE> {
+ define_read!(infallible, read64, readq -> u64);
+
+ define_write!(infallible, write64, writeq <- u64);
+}
+
+#[cfg(CONFIG_64BIT)]
+impl<const SIZE: usize> Io64 for Mmio<SIZE> {
+ define_read!(fallible, try_read64, readq -> u64);
+
+ define_write!(fallible, try_write64, writeq <- u64);
+}
+
+impl<const SIZE: usize> Mmio<SIZE> {
+ /// Converts an `MmioRaw` into an `Mmio` instance, providing the accessors to the MMIO mapping.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `addr` is the start of a valid I/O mapped memory region of size
+ /// `maxsize`.
+ pub unsafe fn from_raw(raw: &MmioRaw<SIZE>) -> &Self {
+ // SAFETY: `Mmio` is a transparent wrapper around `MmioRaw`.
+ unsafe { &*core::ptr::from_ref(raw).cast() }
+ }
+
+ define_read!(infallible, pub read8_relaxed, readb_relaxed -> u8);
+ define_read!(infallible, pub read16_relaxed, readw_relaxed -> u16);
+ define_read!(infallible, pub read32_relaxed, readl_relaxed -> u32);
define_read!(
+ infallible,
#[cfg(CONFIG_64BIT)]
- read64,
- try_read64,
- readq -> u64
+ pub read64_relaxed,
+ readq_relaxed -> u64
);

- define_read!(read8_relaxed, try_read8_relaxed, readb_relaxed -> u8);
- define_read!(read16_relaxed, try_read16_relaxed, readw_relaxed -> u16);
- define_read!(read32_relaxed, try_read32_relaxed, readl_relaxed -> u32);
+ define_read!(fallible, pub try_read8_relaxed, readb_relaxed -> u8);
+ define_read!(fallible, pub try_read16_relaxed, readw_relaxed -> u16);
+ define_read!(fallible, pub try_read32_relaxed, readl_relaxed -> u32);
define_read!(
+ fallible,
#[cfg(CONFIG_64BIT)]
- read64_relaxed,
- try_read64_relaxed,
+ pub try_read64_relaxed,
readq_relaxed -> u64
);

- define_write!(write8, try_write8, writeb <- u8);
- define_write!(write16, try_write16, writew <- u16);
- define_write!(write32, try_write32, writel <- u32);
+ define_write!(infallible, pub write8_relaxed, writeb_relaxed <- u8);
+ define_write!(infallible, pub write16_relaxed, writew_relaxed <- u16);
+ define_write!(infallible, pub write32_relaxed, writel_relaxed <- u32);
define_write!(
+ infallible,
#[cfg(CONFIG_64BIT)]
- write64,
- try_write64,
- writeq <- u64
+ pub write64_relaxed,
+ writeq_relaxed <- u64
);

- define_write!(write8_relaxed, try_write8_relaxed, writeb_relaxed <- u8);
- define_write!(write16_relaxed, try_write16_relaxed, writew_relaxed <- u16);
- define_write!(write32_relaxed, try_write32_relaxed, writel_relaxed <- u32);
+ define_write!(fallible, pub try_write8_relaxed, writeb_relaxed <- u8);
+ define_write!(fallible, pub try_write16_relaxed, writew_relaxed <- u16);
+ define_write!(fallible, pub try_write32_relaxed, writel_relaxed <- u32);
define_write!(
+ fallible,
#[cfg(CONFIG_64BIT)]
- write64_relaxed,
- try_write64_relaxed,
+ pub try_write64_relaxed,
writeq_relaxed <- u64
);
}
diff --git a/rust/kernel/io/mem.rs b/rust/kernel/io/mem.rs
index e4878c131c6d..620022cff401 100644
--- a/rust/kernel/io/mem.rs
+++ b/rust/kernel/io/mem.rs
@@ -16,8 +16,8 @@
Region,
Resource, //
},
- Io,
- IoRaw, //
+ Mmio,
+ MmioRaw, //
},
prelude::*,
};
@@ -212,7 +212,7 @@ pub fn new<'a>(io_request: IoRequest<'a>) -> impl PinInit<Devres<Self>, Error> +
}

impl<const SIZE: usize> Deref for ExclusiveIoMem<SIZE> {
- type Target = Io<SIZE>;
+ type Target = Mmio<SIZE>;

fn deref(&self) -> &Self::Target {
&self.iomem
@@ -226,10 +226,10 @@ fn deref(&self) -> &Self::Target {
///
/// # Invariants
///
-/// [`IoMem`] always holds an [`IoRaw`] instance that holds a valid pointer to the
+/// [`IoMem`] always holds an [`MmioRaw`] instance that holds a valid pointer to the
/// start of the I/O memory mapped region.
pub struct IoMem<const SIZE: usize = 0> {
- io: IoRaw<SIZE>,
+ io: MmioRaw<SIZE>,
}

impl<const SIZE: usize> IoMem<SIZE> {
@@ -264,7 +264,7 @@ fn ioremap(resource: &Resource) -> Result<Self> {
return Err(ENOMEM);
}

- let io = IoRaw::new(addr as usize, size)?;
+ let io = MmioRaw::new(addr as usize, size)?;
let io = IoMem { io };

Ok(io)
@@ -287,10 +287,10 @@ fn drop(&mut self) {
}

impl<const SIZE: usize> Deref for IoMem<SIZE> {
- type Target = Io<SIZE>;
+ type Target = Mmio<SIZE>;

fn deref(&self) -> &Self::Target {
// SAFETY: Safe as by the invariant of `IoMem`.
- unsafe { Io::from_raw(&self.io) }
+ unsafe { Mmio::from_raw(&self.io) }
}
}
diff --git a/rust/kernel/io/poll.rs b/rust/kernel/io/poll.rs
index b1a2570364f4..65d5a370ed14 100644
--- a/rust/kernel/io/poll.rs
+++ b/rust/kernel/io/poll.rs
@@ -45,12 +45,12 @@
/// # Examples
///
/// ```no_run
-/// use kernel::io::{Io, poll::read_poll_timeout};
+/// use kernel::io::{Io, Mmio, poll::read_poll_timeout};
/// use kernel::time::Delta;
///
/// const HW_READY: u16 = 0x01;
///
-/// fn wait_for_hardware<const SIZE: usize>(io: &Io<SIZE>) -> Result {
+/// fn wait_for_hardware<const SIZE: usize>(io: &Mmio<SIZE>) -> Result {
/// read_poll_timeout(
/// // The `op` closure reads the value of a specific status register.
/// || io.try_read16(0x1000),
@@ -128,12 +128,12 @@ pub fn read_poll_timeout<Op, Cond, T>(
/// # Examples
///
/// ```no_run
-/// use kernel::io::{poll::read_poll_timeout_atomic, Io};
+/// use kernel::io::{poll::read_poll_timeout_atomic, Io, Mmio};
/// use kernel::time::Delta;
///
/// const HW_READY: u16 = 0x01;
///
-/// fn wait_for_hardware<const SIZE: usize>(io: &Io<SIZE>) -> Result {
+/// fn wait_for_hardware<const SIZE: usize>(io: &Mmio<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/pci/io.rs b/rust/kernel/pci/io.rs
index 70e3854e7d8d..e3377397666e 100644
--- a/rust/kernel/pci/io.rs
+++ b/rust/kernel/pci/io.rs
@@ -8,8 +8,8 @@
device,
devres::Devres,
io::{
- Io,
- IoRaw, //
+ Mmio,
+ MmioRaw, //
},
prelude::*,
sync::aref::ARef, //
@@ -27,7 +27,7 @@
/// memory mapped PCI BAR and its size.
pub struct Bar<const SIZE: usize = 0> {
pdev: ARef<Device>,
- io: IoRaw<SIZE>,
+ io: MmioRaw<SIZE>,
num: i32,
}

@@ -63,7 +63,7 @@ pub(super) fn new(pdev: &Device, num: u32, name: &CStr) -> Result<Self> {
return Err(ENOMEM);
}

- let io = match IoRaw::new(ioptr, len as usize) {
+ let io = match MmioRaw::new(ioptr, len as usize) {
Ok(io) => io,
Err(err) => {
// SAFETY:
@@ -117,11 +117,11 @@ fn drop(&mut self) {
}

impl<const SIZE: usize> Deref for Bar<SIZE> {
- type Target = Io<SIZE>;
+ type Target = Mmio<SIZE>;

fn deref(&self) -> &Self::Target {
// SAFETY: By the type invariant of `Self`, the MMIO range in `self.io` is properly mapped.
- unsafe { Io::from_raw(&self.io) }
+ unsafe { Mmio::from_raw(&self.io) }
}
}

diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs
index ef04c6401e6a..f7130a359768 100644
--- a/samples/rust/rust_driver_pci.rs
+++ b/samples/rust/rust_driver_pci.rs
@@ -7,6 +7,8 @@
use kernel::{
device::Core,
devres::Devres,
+ io::Io,
+ io::IoKnownSize,
pci,
prelude::*,
sync::aref::ARef, //
--
2.51.0