[PATCH v2 06/16] rust: io: register: allow explicit base type specification
From: Gary Guo
Date: Wed Aug 05 2026 - 12:50:23 EST
Currently registers work for all untyped I/O regions, which is not ideal.
It allows registers defined for device A to work for another device B and
there is no safeguarding at all.
All users of the `register!` macro know what type it will be operating on,
and that type is consistent across the driver. Therefore, add a `base`
parameter to `register!`.
Currently this parameter is unused in the generated code; it will be used
when all users of `register!` is converted to gain the parameter.
Signed-off-by: Gary Guo <gary@xxxxxxxxxxx>
---
rust/kernel/io.rs | 4 +++
rust/kernel/io/register.rs | 84 ++++++++++++++++++++++++++++++++++++++--------
2 files changed, 74 insertions(+), 14 deletions(-)
diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index ae18890866b6..d92e0b6adc99 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -1022,6 +1022,8 @@ fn try_write<T, L>(self, location: L, value: T) -> Result
/// };
///
/// register! {
+ /// base: Region;
+ ///
/// VERSION(u32) @ 0x100 {
/// 15:8 major;
/// 7:0 minor;
@@ -1164,6 +1166,8 @@ fn write<T, L>(self, location: L, value: T)
/// };
///
/// register! {
+ /// base: Region<0x1000>;
+ ///
/// VERSION(u32) @ 0x100 {
/// 15:8 major;
/// 7:0 minor;
diff --git a/rust/kernel/io/register.rs b/rust/kernel/io/register.rs
index e4039e31b4e7..7dca2437b551 100644
--- a/rust/kernel/io/register.rs
+++ b/rust/kernel/io/register.rs
@@ -13,9 +13,14 @@
//! # Simple example
//!
//! ```no_run
-//! use kernel::io::register;
+//! use kernel::io::{
+//! register,
+//! Region,
+//! };
//!
//! register! {
+//! base: Region<0x1000>;
+//!
//! /// Basic information about the chip.
//! pub BOOT_0(u32) @ 0x00000100 {
//! /// Vendor ID.
@@ -55,11 +60,14 @@
//! register,
//! Io,
//! IoLoc,
+//! Region,
//! },
//! num::Bounded,
//! };
-//! # use kernel::io::{Mmio, Region};
+//! # use kernel::io::Mmio;
//! # register! {
+//! # base: Region<0x1000>;
+//! #
//! # pub BOOT_0(u32) @ 0x00000100 {
//! # 15:8 vendor_id;
//! # 7:4 major_revision;
@@ -429,11 +437,14 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// io::{
/// register,
/// Io,
+/// Region,
/// },
/// };
-/// # use kernel::io::{Mmio, Region};
+/// # use kernel::io::Mmio;
///
/// register! {
+/// base: Region<0x1000>;
+///
/// FIXED_REG(u32) @ 0x100 {
/// 15:8 high_byte;
/// 7:0 low_byte;
@@ -464,9 +475,14 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// the context:
///
/// ```no_run
-/// use kernel::io::register;
+/// use kernel::io::{
+/// register,
+/// Region,
+/// };
///
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Scratch register.
/// pub SCRATCH(u32) @ 0x00000200 {
/// 31:0 value;
@@ -516,6 +532,7 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
///
/// ```ignore
/// register! {
+/// ...
/// pub RELATIVE_REG(u32) @ Base + 0x80 {
/// ...
/// }
@@ -542,9 +559,10 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// WithBase,
/// },
/// Io,
+/// Region,
/// },
/// };
-/// # use kernel::io::{Mmio, Region};
+/// # use kernel::io::Mmio;
///
/// // Type used to identify the base.
/// pub struct CpuCtlBase;
@@ -563,6 +581,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
///
/// // This makes `CPU_CTL` accessible from all implementors of `RegisterBase<CpuCtlBase>`.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// CPU core control.
/// pub CPU_CTL(u32) @ CpuCtlBase + 0x10 {
/// 0:0 start;
@@ -579,6 +599,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
///
/// // Aliases can also be defined for relative register.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Alias to CPU core control.
/// pub CPU_CTL_ALIAS(u32) => CpuCtlBase + CPU_CTL {
/// /// Start the aliased CPU core.
@@ -621,15 +643,18 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// register,
/// register::Array,
/// Io,
+/// Region,
/// },
/// };
-/// # use kernel::io::{Mmio, Region};
+/// # use kernel::io::Mmio;
/// # fn get_scratch_idx() -> usize {
/// # 0x15
/// # }
///
/// // Array of 64 consecutive registers with the same layout starting at offset `0x80`.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Scratch registers.
/// pub SCRATCH(u32)[64] @ 0x00000080 {
/// 31:0 value;
@@ -655,6 +680,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// // Alias to a specific register in an array.
/// // Here `SCRATCH[8]` is used to convey the firmware exit code.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Firmware exit status code.
/// pub FIRMWARE_STATUS(u32) => SCRATCH[8] {
/// 7:0 status;
@@ -667,6 +694,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// // Here, each of the 16 registers of the array is separated by 8 bytes, meaning that the
/// // registers of the two declarations below are interleaved.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Scratch registers bank 0.
/// pub SCRATCH_INTERLEAVED_0(u32)[16, stride = 8] @ 0x000000c0 {
/// 31:0 value;
@@ -688,6 +717,7 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
///
/// ```ignore
/// register! {
+/// ...
/// pub RELATIVE_REGISTER_ARRAY(u8)[10, stride = 4] @ Base + 0x100 {
/// ...
/// }
@@ -707,9 +737,10 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// WithBase,
/// },
/// Io,
+/// Region,
/// },
/// };
-/// # use kernel::io::{Mmio, Region};
+/// # use kernel::io::Mmio;
/// # fn get_scratch_idx() -> usize {
/// # 0x15
/// # }
@@ -731,6 +762,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
///
/// // 64 per-cpu scratch registers, arranged as a contiguous array.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Per-CPU scratch registers.
/// pub CPU_SCRATCH(u32)[64] @ CpuCtlBase + 0x00000080 {
/// 31:0 value;
@@ -758,6 +791,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
///
/// // Alias to `SCRATCH[8]` used to convey the firmware exit code.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Per-CPU firmware exit status code.
/// pub CPU_FIRMWARE_STATUS(u32) => CpuCtlBase + CPU_SCRATCH[8] {
/// 7:0 status;
@@ -768,6 +803,8 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// // Here, each of the 16 registers of the array is separated by 8 bytes, meaning that the
/// // registers of the two declarations below are interleaved.
/// register! {
+/// base: Region<0x1000>;
+///
/// /// Scratch registers bank 0.
/// pub CPU_SCRATCH_INTERLEAVED_0(u32)[16, stride = 8] @ CpuCtlBase + 0x00000d00 {
/// 31:0 value;
@@ -786,13 +823,19 @@ fn into_io_op(self) -> (FixedRegisterLoc<T>, T) {
/// ```
#[macro_export]
macro_rules! register {
- () => {};
+ (base: $reg_base:ty;) => {
+ const _: () = {
+ #[allow(unused)]
+ type Base = $reg_base;
+ };
+ };
// Creates a register at a fixed offset of the MMIO space.
//
// This handles all of the fixed offset `@ offset`, alias of register `=> alias` and alias of
// register array element `=> alias[idx]` cases.
(
+ base: $reg_base:ty;
$(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
$(@ $offset:literal)?
$(=> $alias:path $([$alias_idx:expr])? )?
@@ -804,11 +847,12 @@ macro_rules! register {
@ $crate::register!(@offset $(@ $offset)? $(=> $alias $([$alias_idx])?)?)
);
$crate::register!(@io_fixed $(#[$attr])* $vis $name);
- $crate::register!($($rest)*);
+ $crate::register!(base: $reg_base; $($rest)*);
};
// Creates a register at a relative offset from a base address provider.
(
+ base: $reg_base:ty;
$(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) @ $base:ident + $offset:literal
{ $($fields:tt)* }
$($rest:tt)*
@@ -816,11 +860,12 @@ macro_rules! register {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
$crate::register!(@io_base $name @ $offset);
$crate::register!(@io_relative $vis $name @ $base);
- $crate::register!($($rest)*);
+ $crate::register!(base: $reg_base; $($rest)*);
};
// Creates an alias register of relative offset register `alias` with its own fields.
(
+ base: $reg_base:ty;
$(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $base:ident + $alias:ident
{ $($fields:tt)* }
$($rest:tt)*
@@ -828,11 +873,12 @@ macro_rules! register {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
$crate::register!(@io_base $name @ $crate::register!(@offset => $alias));
$crate::register!(@io_relative $vis $name @ $base);
- $crate::register!($($rest)*);
+ $crate::register!(base: $reg_base; $($rest)*);
};
// Creates an array of registers at a fixed offset of the MMIO space.
(
+ base: $reg_base:ty;
$(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
[ $size:expr $(, stride = $stride:expr)? ] @ $offset:literal { $($fields:tt)* }
$($rest:tt)*
@@ -842,11 +888,12 @@ macro_rules! register {
$crate::register!(@io_array $vis $name
[ $size, stride = $crate::register!(@stride $storage $(, $stride)?) ]
);
- $crate::register!($($rest)*);
+ $crate::register!(base: $reg_base; $($rest)*);
};
// Creates an array of registers at a relative offset from a base address provider.
(
+ base: $reg_base:ty;
$(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
[ $size:expr $(, stride = $stride:expr)? ]
@ $base:ident + $offset:literal { $($fields:tt)* }
@@ -857,12 +904,13 @@ macro_rules! register {
$crate::register!(@io_relative_array $vis $name
[ $size, stride = $crate::register!(@stride $storage $(, $stride)?) ] @ $base + $offset
);
- $crate::register!($($rest)*);
+ $crate::register!(base: $reg_base; $($rest)*);
};
// Creates an alias of register `idx` of relative array of registers `alias` with its own
// fields.
(
+ base: $reg_base:ty;
$(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
=> $base:ident + $alias:ident [ $idx:expr ] { $($fields:tt)* }
$($rest:tt)*
@@ -874,7 +922,7 @@ macro_rules! register {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
$crate::register!(@io_base $name @ $crate::register!(@offset => $alias [$idx]));
$crate::register!(@io_relative $vis $name @ $base);
- $crate::register!($($rest)*);
+ $crate::register!(base: $reg_base; $($rest)*);
};
// All the rules below are private helpers.
@@ -962,4 +1010,12 @@ impl $crate::io::register::RegisterArray for $name {
impl $crate::io::register::RelativeRegisterArray for $name {}
};
+
+ // Compatibility rule when base is not specified.
+ ($($rest:tt)*) => {
+ $crate::register!(
+ base: $crate::io::Region;
+ $($rest)*
+ );
+ }
}
--
2.54.0