* [PATCH v2 0/3] rust: add `bitfield!` macro
@ 2026-04-09 14:58 Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 1/3] rust: extract `bitfield!` macro from `register!` Alexandre Courbot
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Alexandre Courbot @ 2026-04-09 14:58 UTC (permalink / raw)
To: Joel Fernandes, Yury Norov, Miguel Ojeda, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Daniel Almeida, David Airlie,
Simona Vetter
Cc: John Hubbard, Alistair Popple, Timur Tabi, Zhi Wang,
Eliot Courtney, linux-kernel, rust-for-linux, driver-core,
dri-devel, Alexandre Courbot
This is the continuation of the `bitfield!` macro which started
alongside the `register!` one before being temporarily integrated into
it [1].
There were still ongoing discussions in [1], notably about improving the
ergonomics of setting bitfield values. This revision doesn't try to
address them yet (although the `with_const` setters partially solve the
issue); it just extracts the `bitfield!` macro and makes it available,
for the following reasons:
- To get the ball rolling again after several months of hiatus,
- Because it is already useful as-is, and ergonomics will be improved
with macros built on top of the existing code,
- To allow dependencies over this series, notably the Nova MM series.
Thus, the discussions about ergonomics could take place as part of this
series, or as a follow-up - after all, bitfields are just registers
without I/O, so the present proposal does not introduce anything that is
not already in the kernel.
[1] https://lore.kernel.org/all/20260120-register-v1-0-723a1743b557@nvidia.com/
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
Alexandre Courbot (2):
rust: extract `bitfield!` macro from `register!`
gpu: nova-core: switch to kernel bitfield macro
Joel Fernandes (1):
rust: bitfield: Add KUNIT tests for bitfield
MAINTAINERS | 8 +
drivers/gpu/nova-core/bitfield.rs | 329 ---------------
drivers/gpu/nova-core/gsp/fw.rs | 15 +-
drivers/gpu/nova-core/nova_core.rs | 3 -
rust/kernel/bitfield.rs | 809 +++++++++++++++++++++++++++++++++++++
rust/kernel/io/register.rs | 246 +----------
rust/kernel/lib.rs | 1 +
7 files changed, 828 insertions(+), 583 deletions(-)
---
base-commit: a7a080bb4236ebe577b6776d940d1717912ff6dd
change-id: 20260408-bitfield-6e18254f4fdc
Best regards,
--
Alexandre Courbot <acourbot@nvidia.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2 1/3] rust: extract `bitfield!` macro from `register!`
2026-04-09 14:58 [PATCH v2 0/3] rust: add `bitfield!` macro Alexandre Courbot
@ 2026-04-09 14:58 ` Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 2/3] rust: bitfield: Add KUNIT tests for bitfield Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 3/3] gpu: nova-core: switch to kernel bitfield macro Alexandre Courbot
2 siblings, 0 replies; 4+ messages in thread
From: Alexandre Courbot @ 2026-04-09 14:58 UTC (permalink / raw)
To: Joel Fernandes, Yury Norov, Miguel Ojeda, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Daniel Almeida, David Airlie,
Simona Vetter
Cc: John Hubbard, Alistair Popple, Timur Tabi, Zhi Wang,
Eliot Courtney, linux-kernel, rust-for-linux, driver-core,
dri-devel, Alexandre Courbot
Extract the bitfield-defining part of the `register!` macro into an
independent macro used to define bitfield types with bounds-checked
accessors.
Each field is represented as a `Bounded` of the appropriate bit width,
ensuring field values are never silently truncated.
Fields can optionally be converted to/from custom types, either fallibly
or infallibly.
Appropriate documentation is also added, and a MAINTAINERS entry created
for the new module.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
MAINTAINERS | 8 +
rust/kernel/bitfield.rs | 491 +++++++++++++++++++++++++++++++++++++++++++++
rust/kernel/io/register.rs | 246 +----------------------
rust/kernel/lib.rs | 1 +
4 files changed, 502 insertions(+), 244 deletions(-)
diff --git a/MAINTAINERS b/MAINTAINERS
index b01791963e25..77f2617ade5d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -23186,6 +23186,14 @@ F: scripts/*rust*
F: tools/testing/selftests/rust/
K: \b(?i:rust)\b
+RUST [BITFIELD]
+M: Alexandre Courbot <acourbot@nvidia.com>
+M: Joel Fernandes <joelagnelf@nvidia.com>
+R: Yury Norov <yury.norov@gmail.com>
+L: rust-for-linux@vger.kernel.org
+S: Maintained
+F: rust/kernel/bitfield.rs
+
RUST [ALLOC]
M: Danilo Krummrich <dakr@kernel.org>
R: Lorenzo Stoakes <ljs@kernel.org>
diff --git a/rust/kernel/bitfield.rs b/rust/kernel/bitfield.rs
new file mode 100644
index 000000000000..f5948eec8a76
--- /dev/null
+++ b/rust/kernel/bitfield.rs
@@ -0,0 +1,491 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Support for defining bitfields as Rust structures.
+//!
+//! The [`bitfield!`](kernel::bitfield!) macro declares integer types that are split into distinct
+//! bit fields of arbitrary length. Each field is typed using [`Bounded`](kernel::num::Bounded) to
+//! ensure values are properly validated and to avoid implicit data loss.
+//!
+//! # Example
+//!
+//! ```rust
+//! use kernel::bitfield;
+//! use kernel::num::Bounded;
+//!
+//! bitfield! {
+//! pub struct Rgb(u16) {
+//! 15:11 blue;
+//! 10:5 green;
+//! 4:0 red;
+//! }
+//! }
+//!
+//! // Valid value for the `blue` field.
+//! let blue = Bounded::<u16, 5>::new::<0x18>();
+//!
+//! // Setters can be chained. Values ranges are checked at compile-time.
+//! let color = Rgb::zeroed()
+//! // Compile-time bounds check of constant value.
+//! .with_const_red::<0x10>()
+//! .with_const_green::<0x1f>()
+//! // A `Bounded` can also be passed.
+//! .with_blue(blue);
+//!
+//! assert_eq!(color.red(), 0x10);
+//! assert_eq!(color.green(), 0x1f);
+//! assert_eq!(color.blue(), 0x18);
+//! assert_eq!(
+//! color.into_raw(),
+//! (0x18 << Rgb::BLUE_SHIFT) + (0x1f << Rgb::GREEN_SHIFT) + 0x10,
+//! );
+//!
+//! // Convert to/from the backing storage type.
+//! let raw: u16 = color.into();
+//! assert_eq!(Rgb::from(raw), color);
+//! ```
+//!
+//! # Syntax
+//!
+//! ```text
+//! bitfield! {
+//! #[attributes]
+//! // Documentation for `Name`.
+//! pub struct Name(storage_type) {
+//! // `field_1` documentation.
+//! hi:lo field_1;
+//! // `field_2` documentation.
+//! hi:lo field_2 => ConvertedType;
+//! // `field_3` documentation.
+//! hi:lo field_3 ?=> ConvertedType;
+//! ...
+//! }
+//! }
+//! ```
+//!
+//! - `storage_type`: The underlying integer type (`u8`, `u16`, `u32`, `u64`).
+//! - `hi:lo`: Bit range (inclusive), where `hi >= lo`.
+//! - `=> Type`: Optional infallible conversion (see [below](#infallible-conversion-)).
+//! - `?=> Type`: Optional fallible conversion (see [below](#fallible-conversion-)).
+//! - Documentation strings and attributes are optional.
+//!
+//! # Generated code
+//!
+//! Each field is internally represented as a [`Bounded`] parameterized by its bit width. Field
+//! values can either be set/retrieved directly, or converted from/to another type.
+//!
+//! The use of `Bounded` for each field enforces bounds-checking (at build time or runtime) of every
+//! value assigned to a field. This ensures that data is never accidentally truncated.
+//!
+//! The macro generates the bitfield type, [`From`] and [`Into`] implementations for its storage
+//! type, as well as [`Debug`] and [`Zeroable`](pin_init::Zeroable) implementations.
+//!
+//! For each field, it also generates:
+//!
+//! - `with_field(value)` — infallible setter; the argument type must be statically known to fit
+//! the field width.
+//! - `with_const_field::<VALUE>()` — const setter; the value is validated at compile time.
+//! Usually shorter to use than `with_field` for constant values as it doesn't require
+//! constructing a `Bounded`.
+//! - `try_with_field(value)` — fallible setter. Returns an error if the value is out of range.
+//! - `FIELD_MASK`, `FIELD_SHIFT`, `FIELD_RANGE` - constants for manual bit manipulation.
+//!
+//! # Implicit conversions
+//!
+//! Types that fit entirely within a field's bit width can be used directly with setters. For
+//! example, `bool` works with single-bit fields, and `u8` works with 8-bit fields:
+//!
+//! ```rust
+//! use kernel::bitfield;
+//!
+//! bitfield! {
+//! pub struct Flags(u32) {
+//! 15:8 byte_field;
+//! 0:0 flag;
+//! }
+//! }
+//!
+//! let flags = Flags::zeroed()
+//! .with_byte_field(0x42_u8)
+//! .with_flag(true);
+//!
+//! assert_eq!(flags.into_raw(), (0x42 << Flags::BYTE_FIELD_SHIFT) | 1);
+//! ```
+//!
+//! # Runtime bounds checking
+//!
+//! When a value is not known at compile time, use `try_with_field()` to check bounds at runtime:
+//!
+//! ```rust
+//! use kernel::bitfield;
+//!
+//! bitfield! {
+//! pub struct Config(u8) {
+//! 3:0 nibble;
+//! }
+//! }
+//!
+//! fn set_nibble(config: Config, value: u8) -> Result<Config, Error> {
+//! // Returns `EOVERFLOW` if `value > 0xf`.
+//! config.try_with_nibble(value)
+//! }
+//! # Ok::<(), Error>(())
+//! ```
+//!
+//! # Type conversion
+//!
+//! Fields can be automatically converted to/from a custom type using `=>` (infallible) or `?=>`
+//! (fallible). The custom type must implement the appropriate `From` or `TryFrom` traits with
+//! `Bounded`.
+//!
+//! ## Infallible conversion (`=>`)
+//!
+//! Use this when all possible bit patterns of a field map to valid values:
+//!
+//! ```rust
+//! use kernel::bitfield;
+//! use kernel::num::Bounded;
+//!
+//! #[derive(Debug, Clone, Copy, PartialEq)]
+//! enum Power {
+//! Off,
+//! On,
+//! }
+//!
+//! impl From<Bounded<u32, 1>> for Power {
+//! fn from(v: Bounded<u32, 1>) -> Self {
+//! match *v {
+//! 0 => Power::Off,
+//! _ => Power::On,
+//! }
+//! }
+//! }
+//!
+//! impl From<Power> for Bounded<u32, 1> {
+//! fn from(p: Power) -> Self {
+//! (p as u32 != 0).into()
+//! }
+//! }
+//!
+//! bitfield! {
+//! pub struct Control(u32) {
+//! 0:0 power => Power;
+//! }
+//! }
+//!
+//! let ctrl = Control::zeroed().with_power(Power::On);
+//! assert_eq!(ctrl.power(), Power::On);
+//! ```
+//!
+//! ## Fallible conversion (`?=>`)
+//!
+//! Use this when some bit patterns of a field are invalid. The getter returns a [`Result`]:
+//!
+//! ```rust
+//! use kernel::bitfield;
+//! use kernel::num::Bounded;
+//!
+//! #[derive(Debug, Clone, Copy, PartialEq)]
+//! enum Mode {
+//! Low = 0,
+//! High = 1,
+//! Auto = 2,
+//! // 3 is invalid
+//! }
+//!
+//! impl TryFrom<Bounded<u32, 2>> for Mode {
+//! type Error = u32;
+//!
+//! fn try_from(v: Bounded<u32, 2>) -> Result<Self, u32> {
+//! match *v {
+//! 0 => Ok(Mode::Low),
+//! 1 => Ok(Mode::High),
+//! 2 => Ok(Mode::Auto),
+//! n => Err(n),
+//! }
+//! }
+//! }
+//!
+//! impl From<Mode> for Bounded<u32, 2> {
+//! fn from(m: Mode) -> Self {
+//! match m {
+//! Mode::Low => Bounded::<u32, _>::new::<0>(),
+//! Mode::High => Bounded::<u32, _>::new::<1>(),
+//! Mode::Auto => Bounded::<u32, _>::new::<2>(),
+//! }
+//! }
+//! }
+//!
+//! bitfield! {
+//! pub struct Config(u32) {
+//! 1:0 mode ?=> Mode;
+//! }
+//! }
+//!
+//! let cfg = Config::zeroed().with_mode(Mode::Auto);
+//! assert_eq!(cfg.mode(), Ok(Mode::Auto));
+//!
+//! // Invalid bit pattern returns an error.
+//! assert_eq!(Config::from(0b11).mode(), Err(3));
+//! ```
+//!
+//! [`Bounded`]: kernel::num::Bounded
+
+/// Defines a bitfield struct with bounds-checked accessors for individual bit ranges.
+///
+/// See the [`mod@kernel::bitfield`] module for full documentation and examples.
+#[macro_export]
+macro_rules! bitfield {
+ // Entry point defining the bitfield struct, its implementations and its field accessors.
+ (
+ $(#[$attr:meta])* $vis:vis struct $name:ident($storage:ty) { $($fields:tt)* }
+ ) => {
+ $crate::bitfield!(@core
+ #[allow(non_camel_case_types)]
+ $(#[$attr])* $vis $name $storage
+ );
+ $crate::bitfield!(@fields $vis $name $storage { $($fields)* });
+ };
+
+ // All rules below are helpers.
+
+ // Defines the wrapper `$name` type and its conversions from/to the storage type.
+ (@core $(#[$attr:meta])* $vis:vis $name:ident $storage:ty) => {
+ $(#[$attr])*
+ #[repr(transparent)]
+ #[derive(Clone, Copy, PartialEq, Eq)]
+ $vis struct $name {
+ inner: $storage,
+ }
+
+ #[allow(dead_code)]
+ impl $name {
+ /// Creates a bitfield from a raw value.
+ #[inline(always)]
+ $vis const fn from_raw(value: $storage) -> Self {
+ Self{ inner: value }
+ }
+
+ /// Turns this bitfield into its raw value.
+ ///
+ /// This is similar to the [`From`] implementation, but is shorter to invoke in
+ /// most cases.
+ #[inline(always)]
+ $vis const fn into_raw(self) -> $storage {
+ self.inner
+ }
+ }
+
+ // SAFETY: `$storage` is `Zeroable` and `$name` is transparent.
+ unsafe impl ::pin_init::Zeroable for $name {}
+
+ impl ::core::convert::From<$name> for $storage {
+ #[inline(always)]
+ fn from(val: $name) -> $storage {
+ val.into_raw()
+ }
+ }
+
+ impl ::core::convert::From<$storage> for $name {
+ #[inline(always)]
+ fn from(val: $storage) -> $name {
+ Self::from_raw(val)
+ }
+ }
+ };
+
+ // Definitions requiring knowledge of individual fields: private and public field accessors,
+ // and `Debug` implementation.
+ (@fields $vis:vis $name:ident $storage:ty {
+ $($(#[doc = $doc:expr])* $hi:literal:$lo:literal $field:ident
+ $(?=> $try_into_type:ty)?
+ $(=> $into_type:ty)?
+ ;
+ )*
+ }
+ ) => {
+ #[allow(dead_code)]
+ impl $name {
+ $(
+ $crate::bitfield!(@private_field_accessors $vis $name $storage : $hi:$lo $field);
+ $crate::bitfield!(
+ @public_field_accessors $(#[doc = $doc])* $vis $name $storage : $hi:$lo $field
+ $(?=> $try_into_type)?
+ $(=> $into_type)?
+ );
+ )*
+ }
+
+ $crate::bitfield!(@debug $name { $($field;)* });
+ };
+
+ // Private field accessors working with the exact `Bounded` type for the field.
+ (
+ @private_field_accessors $vis:vis $name:ident $storage:ty : $hi:tt:$lo:tt $field:ident
+ ) => {
+ ::kernel::macros::paste!(
+ $vis const [<$field:upper _RANGE>]: ::core::ops::RangeInclusive<u8> = $lo..=$hi;
+ $vis const [<$field:upper _MASK>]: $storage =
+ ((((1 << $hi) - 1) << 1) + 1) - ((1 << $lo) - 1);
+ $vis const [<$field:upper _SHIFT>]: u32 = $lo;
+ );
+
+ ::kernel::macros::paste!(
+ fn [<__ $field>](self) ->
+ ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }> {
+ // Left shift to align the field's MSB with the storage MSB.
+ const ALIGN_TOP: u32 = $storage::BITS - ($hi + 1);
+ // Right shift to move the top-aligned field to bit 0 of the storage.
+ const ALIGN_BOTTOM: u32 = ALIGN_TOP + $lo;
+
+ // Extract the field using two shifts. `Bounded::shr` produces the correctly-sized
+ // output type.
+ let val = ::kernel::num::Bounded::<$storage, { $storage::BITS }>::from(
+ self.inner << ALIGN_TOP
+ );
+ val.shr::<ALIGN_BOTTOM, { $hi + 1 - $lo } >()
+ }
+
+ const fn [<__with_ $field>](
+ mut self,
+ value: ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>,
+ ) -> Self
+ {
+ const MASK: $storage = <$name>::[<$field:upper _MASK>];
+ const SHIFT: u32 = <$name>::[<$field:upper _SHIFT>];
+
+ let value = value.get() << SHIFT;
+ self.inner = (self.inner & !MASK) | value;
+
+ self
+ }
+ );
+ };
+
+ // Public accessors for fields infallibly (`=>`) converted to a type.
+ (
+ @public_field_accessors $(#[doc = $doc:expr])* $vis:vis $name:ident $storage:ty :
+ $hi:literal:$lo:literal $field:ident => $into_type:ty
+ ) => {
+ ::kernel::macros::paste!(
+
+ $(#[doc = $doc])*
+ #[doc = "Returns the value of this field."]
+ #[inline(always)]
+ $vis fn $field(self) -> $into_type
+ {
+ self.[<__ $field>]().into()
+ }
+
+ $(#[doc = $doc])*
+ #[doc = "Sets this field to the given `value`."]
+ #[inline(always)]
+ $vis fn [<with_ $field>](self, value: $into_type) -> Self
+ {
+ self.[<__with_ $field>](value.into())
+ }
+
+ );
+ };
+
+ // Public accessors for fields fallibly (`?=>`) converted to a type.
+ (
+ @public_field_accessors $(#[doc = $doc:expr])* $vis:vis $name:ident $storage:ty :
+ $hi:tt:$lo:tt $field:ident ?=> $try_into_type:ty
+ ) => {
+ ::kernel::macros::paste!(
+
+ $(#[doc = $doc])*
+ #[doc = "Returns the value of this field."]
+ #[inline(always)]
+ $vis fn $field(self) ->
+ Result<
+ $try_into_type,
+ <$try_into_type as ::core::convert::TryFrom<
+ ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>
+ >>::Error
+ >
+ {
+ self.[<__ $field>]().try_into()
+ }
+
+ $(#[doc = $doc])*
+ #[doc = "Sets this field to the given `value`."]
+ #[inline(always)]
+ $vis fn [<with_ $field>](self, value: $try_into_type) -> Self
+ {
+ self.[<__with_ $field>](value.into())
+ }
+
+ );
+ };
+
+ // Public accessors for fields not converted to a type.
+ (
+ @public_field_accessors $(#[doc = $doc:expr])* $vis:vis $name:ident $storage:ty :
+ $hi:tt:$lo:tt $field:ident
+ ) => {
+ ::kernel::macros::paste!(
+
+ $(#[doc = $doc])*
+ #[doc = "Returns the value of this field."]
+ #[inline(always)]
+ $vis fn $field(self) ->
+ ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>
+ {
+ self.[<__ $field>]()
+ }
+
+ $(#[doc = $doc])*
+ #[doc = "Sets this field to the compile-time constant `VALUE`."]
+ #[inline(always)]
+ $vis const fn [<with_const_ $field>]<const VALUE: $storage>(self) -> Self {
+ self.[<__with_ $field>](
+ ::kernel::num::Bounded::<$storage, { $hi + 1 - $lo }>::new::<VALUE>()
+ )
+ }
+
+ $(#[doc = $doc])*
+ #[doc = "Sets this field to the given `value`."]
+ #[inline(always)]
+ $vis fn [<with_ $field>]<T>(
+ self,
+ value: T,
+ ) -> Self
+ where T: Into<::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>>,
+ {
+ self.[<__with_ $field>](value.into())
+ }
+
+ $(#[doc = $doc])*
+ #[doc = "Tries to set this field to `value`, returning an error if it is out of range."]
+ #[inline(always)]
+ $vis fn [<try_with_ $field>]<T>(
+ self,
+ value: T,
+ ) -> ::kernel::error::Result<Self>
+ where T: ::kernel::num::TryIntoBounded<$storage, { $hi + 1 - $lo }>,
+ {
+ Ok(
+ self.[<__with_ $field>](
+ value.try_into_bounded().ok_or(::kernel::error::code::EOVERFLOW)?
+ )
+ )
+ }
+
+ );
+ };
+
+ // `Debug` implementation.
+ (@debug $name:ident { $($field:ident;)* }) => {
+ impl ::kernel::fmt::Debug for $name {
+ fn fmt(&self, f: &mut ::kernel::fmt::Formatter<'_>) -> ::kernel::fmt::Result {
+ f.debug_struct(stringify!($name))
+ .field("<raw>", &::kernel::prelude::fmt!("{:#x}", self.inner))
+ $(
+ .field(stringify!($field), &self.$field())
+ )*
+ .finish()
+ }
+ }
+ };
+}
diff --git a/rust/kernel/io/register.rs b/rust/kernel/io/register.rs
index abc49926abfe..388647f28292 100644
--- a/rust/kernel/io/register.rs
+++ b/rust/kernel/io/register.rs
@@ -956,11 +956,10 @@ macro_rules! register {
(
@bitfield $(#[$attr:meta])* $vis:vis struct $name:ident($storage:ty) { $($fields:tt)* }
) => {
- $crate::register!(@bitfield_core
+ $crate::bitfield!(
#[allow(non_camel_case_types)]
- $(#[$attr])* $vis $name $storage
+ $(#[$attr])* $vis struct $name($storage) { $($fields)* }
);
- $crate::register!(@bitfield_fields $vis $name $storage { $($fields)* });
};
// Implementations shared by all registers types.
@@ -1016,245 +1015,4 @@ impl $crate::io::register::RegisterArray for $name {
impl $crate::io::register::RelativeRegisterArray for $name {}
};
-
- // Defines the wrapper `$name` type and its conversions from/to the storage type.
- (@bitfield_core $(#[$attr:meta])* $vis:vis $name:ident $storage:ty) => {
- $(#[$attr])*
- #[repr(transparent)]
- #[derive(Clone, Copy, PartialEq, Eq)]
- $vis struct $name {
- inner: $storage,
- }
-
- #[allow(dead_code)]
- impl $name {
- /// Creates a bitfield from a raw value.
- #[inline(always)]
- $vis const fn from_raw(value: $storage) -> Self {
- Self{ inner: value }
- }
-
- /// Turns this bitfield into its raw value.
- ///
- /// This is similar to the [`From`] implementation, but is shorter to invoke in
- /// most cases.
- #[inline(always)]
- $vis const fn into_raw(self) -> $storage {
- self.inner
- }
- }
-
- // SAFETY: `$storage` is `Zeroable` and `$name` is transparent.
- unsafe impl ::pin_init::Zeroable for $name {}
-
- impl ::core::convert::From<$name> for $storage {
- #[inline(always)]
- fn from(val: $name) -> $storage {
- val.into_raw()
- }
- }
-
- impl ::core::convert::From<$storage> for $name {
- #[inline(always)]
- fn from(val: $storage) -> $name {
- Self::from_raw(val)
- }
- }
- };
-
- // Definitions requiring knowledge of individual fields: private and public field accessors,
- // and `Debug` implementation.
- (@bitfield_fields $vis:vis $name:ident $storage:ty {
- $($(#[doc = $doc:expr])* $hi:literal:$lo:literal $field:ident
- $(?=> $try_into_type:ty)?
- $(=> $into_type:ty)?
- ;
- )*
- }
- ) => {
- #[allow(dead_code)]
- impl $name {
- $(
- $crate::register!(@private_field_accessors $vis $name $storage : $hi:$lo $field);
- $crate::register!(
- @public_field_accessors $(#[doc = $doc])* $vis $name $storage : $hi:$lo $field
- $(?=> $try_into_type)?
- $(=> $into_type)?
- );
- )*
- }
-
- $crate::register!(@debug $name { $($field;)* });
- };
-
- // Private field accessors working with the exact `Bounded` type for the field.
- (
- @private_field_accessors $vis:vis $name:ident $storage:ty : $hi:tt:$lo:tt $field:ident
- ) => {
- ::kernel::macros::paste!(
- $vis const [<$field:upper _RANGE>]: ::core::ops::RangeInclusive<u8> = $lo..=$hi;
- $vis const [<$field:upper _MASK>]: $storage =
- ((((1 << $hi) - 1) << 1) + 1) - ((1 << $lo) - 1);
- $vis const [<$field:upper _SHIFT>]: u32 = $lo;
- );
-
- ::kernel::macros::paste!(
- fn [<__ $field>](self) ->
- ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }> {
- // Left shift to align the field's MSB with the storage MSB.
- const ALIGN_TOP: u32 = $storage::BITS - ($hi + 1);
- // Right shift to move the top-aligned field to bit 0 of the storage.
- const ALIGN_BOTTOM: u32 = ALIGN_TOP + $lo;
-
- // Extract the field using two shifts. `Bounded::shr` produces the correctly-sized
- // output type.
- let val = ::kernel::num::Bounded::<$storage, { $storage::BITS }>::from(
- self.inner << ALIGN_TOP
- );
- val.shr::<ALIGN_BOTTOM, { $hi + 1 - $lo } >()
- }
-
- const fn [<__with_ $field>](
- mut self,
- value: ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>,
- ) -> Self
- {
- const MASK: $storage = <$name>::[<$field:upper _MASK>];
- const SHIFT: u32 = <$name>::[<$field:upper _SHIFT>];
-
- let value = value.get() << SHIFT;
- self.inner = (self.inner & !MASK) | value;
-
- self
- }
- );
- };
-
- // Public accessors for fields infallibly (`=>`) converted to a type.
- (
- @public_field_accessors $(#[doc = $doc:expr])* $vis:vis $name:ident $storage:ty :
- $hi:literal:$lo:literal $field:ident => $into_type:ty
- ) => {
- ::kernel::macros::paste!(
-
- $(#[doc = $doc])*
- #[doc = "Returns the value of this field."]
- #[inline(always)]
- $vis fn $field(self) -> $into_type
- {
- self.[<__ $field>]().into()
- }
-
- $(#[doc = $doc])*
- #[doc = "Sets this field to the given `value`."]
- #[inline(always)]
- $vis fn [<with_ $field>](self, value: $into_type) -> Self
- {
- self.[<__with_ $field>](value.into())
- }
-
- );
- };
-
- // Public accessors for fields fallibly (`?=>`) converted to a type.
- (
- @public_field_accessors $(#[doc = $doc:expr])* $vis:vis $name:ident $storage:ty :
- $hi:tt:$lo:tt $field:ident ?=> $try_into_type:ty
- ) => {
- ::kernel::macros::paste!(
-
- $(#[doc = $doc])*
- #[doc = "Returns the value of this field."]
- #[inline(always)]
- $vis fn $field(self) ->
- Result<
- $try_into_type,
- <$try_into_type as ::core::convert::TryFrom<
- ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>
- >>::Error
- >
- {
- self.[<__ $field>]().try_into()
- }
-
- $(#[doc = $doc])*
- #[doc = "Sets this field to the given `value`."]
- #[inline(always)]
- $vis fn [<with_ $field>](self, value: $try_into_type) -> Self
- {
- self.[<__with_ $field>](value.into())
- }
-
- );
- };
-
- // Public accessors for fields not converted to a type.
- (
- @public_field_accessors $(#[doc = $doc:expr])* $vis:vis $name:ident $storage:ty :
- $hi:tt:$lo:tt $field:ident
- ) => {
- ::kernel::macros::paste!(
-
- $(#[doc = $doc])*
- #[doc = "Returns the value of this field."]
- #[inline(always)]
- $vis fn $field(self) ->
- ::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>
- {
- self.[<__ $field>]()
- }
-
- $(#[doc = $doc])*
- #[doc = "Sets this field to the compile-time constant `VALUE`."]
- #[inline(always)]
- $vis const fn [<with_const_ $field>]<const VALUE: $storage>(self) -> Self {
- self.[<__with_ $field>](
- ::kernel::num::Bounded::<$storage, { $hi + 1 - $lo }>::new::<VALUE>()
- )
- }
-
- $(#[doc = $doc])*
- #[doc = "Sets this field to the given `value`."]
- #[inline(always)]
- $vis fn [<with_ $field>]<T>(
- self,
- value: T,
- ) -> Self
- where T: Into<::kernel::num::Bounded<$storage, { $hi + 1 - $lo }>>,
- {
- self.[<__with_ $field>](value.into())
- }
-
- $(#[doc = $doc])*
- #[doc = "Tries to set this field to `value`, returning an error if it is out of range."]
- #[inline(always)]
- $vis fn [<try_with_ $field>]<T>(
- self,
- value: T,
- ) -> ::kernel::error::Result<Self>
- where T: ::kernel::num::TryIntoBounded<$storage, { $hi + 1 - $lo }>,
- {
- Ok(
- self.[<__with_ $field>](
- value.try_into_bounded().ok_or(::kernel::error::code::EOVERFLOW)?
- )
- )
- }
-
- );
- };
-
- // `Debug` implementation.
- (@debug $name:ident { $($field:ident;)* }) => {
- impl ::kernel::fmt::Debug for $name {
- fn fmt(&self, f: &mut ::kernel::fmt::Formatter<'_>) -> ::kernel::fmt::Result {
- f.debug_struct(stringify!($name))
- .field("<raw>", &::kernel::prelude::fmt!("{:#x}", self.inner))
- $(
- .field(stringify!($field), &self.$field())
- )*
- .finish()
- }
- }
- };
}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 40de00ce4f97..31e5f5908dfc 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -77,6 +77,7 @@
pub mod alloc;
#[cfg(CONFIG_AUXILIARY_BUS)]
pub mod auxiliary;
+pub mod bitfield;
pub mod bitmap;
pub mod bits;
#[cfg(CONFIG_BLOCK)]
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/3] rust: bitfield: Add KUNIT tests for bitfield
2026-04-09 14:58 [PATCH v2 0/3] rust: add `bitfield!` macro Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 1/3] rust: extract `bitfield!` macro from `register!` Alexandre Courbot
@ 2026-04-09 14:58 ` Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 3/3] gpu: nova-core: switch to kernel bitfield macro Alexandre Courbot
2 siblings, 0 replies; 4+ messages in thread
From: Alexandre Courbot @ 2026-04-09 14:58 UTC (permalink / raw)
To: Joel Fernandes, Yury Norov, Miguel Ojeda, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Daniel Almeida, David Airlie,
Simona Vetter
Cc: John Hubbard, Alistair Popple, Timur Tabi, Zhi Wang,
Eliot Courtney, linux-kernel, rust-for-linux, driver-core,
dri-devel, Alexandre Courbot
From: Joel Fernandes <joelagnelf@nvidia.com>
Add KUNIT tests to make sure the macro is working correctly.
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
[acourbot: update code to latest bitfield! macro.]
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
rust/kernel/bitfield.rs | 318 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 318 insertions(+)
diff --git a/rust/kernel/bitfield.rs b/rust/kernel/bitfield.rs
index f5948eec8a76..9ab8dafff36c 100644
--- a/rust/kernel/bitfield.rs
+++ b/rust/kernel/bitfield.rs
@@ -489,3 +489,321 @@ fn fmt(&self, f: &mut ::kernel::fmt::Formatter<'_>) -> ::kernel::fmt::Result {
}
};
}
+
+#[::kernel::macros::kunit_tests(kernel_bitfield)]
+mod tests {
+ use core::convert::TryFrom;
+
+ use pin_init::Zeroable;
+
+ use kernel::num::Bounded;
+
+ // Enum types for testing => and ?=> conversions
+ #[derive(Debug, Clone, Copy, PartialEq)]
+ enum MemoryType {
+ Unmapped = 0,
+ Normal = 1,
+ Device = 2,
+ Reserved = 3,
+ }
+
+ impl TryFrom<Bounded<u64, 4>> for MemoryType {
+ type Error = u64;
+ fn try_from(value: Bounded<u64, 4>) -> Result<Self, Self::Error> {
+ match value.get() {
+ 0 => Ok(MemoryType::Unmapped),
+ 1 => Ok(MemoryType::Normal),
+ 2 => Ok(MemoryType::Device),
+ 3 => Ok(MemoryType::Reserved),
+ _ => Err(value.get()),
+ }
+ }
+ }
+
+ impl From<MemoryType> for Bounded<u64, 4> {
+ fn from(mt: MemoryType) -> Bounded<u64, 4> {
+ Bounded::from_expr(mt as u64)
+ }
+ }
+
+ #[derive(Debug, Clone, Copy, PartialEq)]
+ enum Priority {
+ Low = 0,
+ Medium = 1,
+ High = 2,
+ Critical = 3,
+ }
+
+ impl From<Bounded<u16, 2>> for Priority {
+ fn from(value: Bounded<u16, 2>) -> Self {
+ match value & 0x3 {
+ 0 => Priority::Low,
+ 1 => Priority::Medium,
+ 2 => Priority::High,
+ _ => Priority::Critical,
+ }
+ }
+ }
+
+ impl From<Priority> for Bounded<u16, 2> {
+ fn from(p: Priority) -> Bounded<u16, 2> {
+ Bounded::from_expr(p as u16)
+ }
+ }
+
+ bitfield! {
+ struct TestPageTableEntry(u64) {
+ 0:0 present;
+ 1:1 writable;
+ 11:9 available;
+ 15:12 mem_type ?=> MemoryType;
+ 51:16 pfn;
+ 61:52 available2;
+ }
+ }
+
+ bitfield! {
+ struct TestControlRegister(u16) {
+ 0:0 enable;
+ 3:1 mode;
+ 5:4 priority => Priority;
+ 7:4 priority_nibble;
+ 15:8 channel;
+ }
+ }
+
+ bitfield! {
+ struct TestStatusRegister(u8) {
+ 0:0 ready;
+ 1:1 error;
+ 3:2 state;
+ 7:4 reserved;
+ 7:0 full_byte; // For entire register
+ }
+ }
+
+ #[test]
+ fn test_single_bits() {
+ let mut pte = TestPageTableEntry::zeroed();
+
+ assert!(!pte.present().into_bool());
+ assert!(!pte.writable().into_bool());
+ assert_eq!(u64::from(pte), 0x0);
+
+ pte = pte.with_present(true);
+ assert!(pte.present().into_bool());
+ assert_eq!(u64::from(pte), 0x1);
+
+ pte = pte.with_writable(true);
+ assert!(pte.writable().into_bool());
+ assert_eq!(u64::from(pte), 0x3);
+
+ pte = pte.with_writable(false);
+ assert!(!pte.writable().into_bool());
+ assert_eq!(u64::from(pte), 0x1);
+
+ assert_eq!(pte.available(), 0);
+ pte = pte.with_const_available::<0x5>();
+ assert_eq!(pte.available(), 0x5);
+ assert_eq!(u64::from(pte), 0xA01);
+ }
+
+ #[test]
+ fn test_range_fields() {
+ let mut pte = TestPageTableEntry::zeroed();
+ assert_eq!(u64::from(pte), 0x0);
+
+ pte = pte.with_const_pfn::<0x123456>();
+ assert_eq!(pte.pfn(), 0x123456);
+ assert_eq!(u64::from(pte), 0x1234560000);
+
+ pte = pte.with_const_available::<0x7>();
+ assert_eq!(pte.available(), 0x7);
+ assert_eq!(u64::from(pte), 0x1234560E00);
+
+ pte = pte.with_const_available2::<0x3FF>();
+ assert_eq!(pte.available2(), 0x3FF);
+ assert_eq!(u64::from(pte), 0x3FF0_0012_3456_0E00u64);
+
+ // Test TryFrom with ?=> for MemoryType
+ pte = pte.with_mem_type(MemoryType::Device);
+ assert_eq!(pte.mem_type(), Ok(MemoryType::Device));
+ assert_eq!(u64::from(pte), 0x3FF0_0012_3456_2E00u64);
+
+ pte = pte.with_mem_type(MemoryType::Normal);
+ assert_eq!(pte.mem_type(), Ok(MemoryType::Normal));
+ assert_eq!(u64::from(pte), 0x3FF0_0012_3456_1E00u64);
+
+ // Test all valid values for mem_type
+ pte = pte.with_mem_type(MemoryType::Reserved);
+ assert_eq!(pte.mem_type(), Ok(MemoryType::Reserved));
+ assert_eq!(u64::from(pte), 0x3FF0_0012_3456_3E00u64);
+
+ // Test failure case using mem_type field which has 4 bits (0-15)
+ // MemoryType only handles 0-3, so values 4-15 should return Err
+ let mut raw = pte.into_raw();
+ // Set bits 15:12 to 7 (invalid for MemoryType)
+ raw = (raw & !::kernel::bits::genmask_u64(12..=15)) | (0x7 << 12);
+ let invalid_pte = TestPageTableEntry::from_raw(raw);
+ // Should return Err with the invalid value
+ assert_eq!(invalid_pte.mem_type(), Err(0x7));
+
+ // Test a valid value after testing invalid to ensure both cases work
+ // Set bits 15:12 to 2 (valid: Device)
+ raw = (raw & !::kernel::bits::genmask_u64(12..=15)) | (0x2 << 12);
+ let valid_pte = TestPageTableEntry::from_raw(raw);
+ assert_eq!(valid_pte.mem_type(), Ok(MemoryType::Device));
+
+ const MAX_PFN: u64 = ::kernel::bits::genmask_u64(0..=35);
+ pte = pte.with_const_pfn::<{ MAX_PFN }>();
+ assert_eq!(pte.pfn(), MAX_PFN);
+ }
+
+ #[test]
+ fn test_builder_pattern() {
+ let pte = TestPageTableEntry::zeroed()
+ .with_present(true)
+ .with_writable(true)
+ .with_const_available::<0x7>()
+ .with_const_pfn::<0xABCDEF>()
+ .with_mem_type(MemoryType::Reserved)
+ .with_const_available2::<0x3FF>();
+
+ assert!(pte.present().into_bool());
+ assert!(pte.writable().into_bool());
+ assert_eq!(pte.available(), 0x7);
+ assert_eq!(pte.pfn(), 0xABCDEF);
+ assert_eq!(pte.mem_type(), Ok(MemoryType::Reserved));
+ assert_eq!(pte.available2(), 0x3FF);
+ }
+
+ #[test]
+ fn test_raw_operations() {
+ let raw_value = 0x3FF0000031233E03u64;
+
+ let pte = TestPageTableEntry::from_raw(raw_value);
+ assert_eq!(u64::from(pte), raw_value);
+
+ assert!(pte.present().into_bool());
+ assert!(pte.writable().into_bool());
+ assert_eq!(pte.available(), 0x7);
+ assert_eq!(pte.pfn(), 0x3123);
+ assert_eq!(pte.mem_type(), Ok(MemoryType::Reserved));
+ assert_eq!(pte.available2(), 0x3FF);
+
+ // Test using direct constructor syntax TestStruct(value)
+ let pte2 = TestPageTableEntry::from_raw(raw_value);
+ assert_eq!(u64::from(pte2), raw_value);
+ }
+
+ #[test]
+ fn test_u16_bitfield() {
+ let mut ctrl = TestControlRegister::zeroed();
+
+ assert!(!ctrl.enable().into_bool());
+ assert_eq!(ctrl.mode(), 0);
+ assert_eq!(ctrl.priority(), Priority::Low);
+ assert_eq!(ctrl.priority_nibble(), 0);
+ assert_eq!(ctrl.channel(), 0);
+
+ ctrl = ctrl.with_enable(true);
+ assert!(ctrl.enable().into_bool());
+
+ ctrl = ctrl.with_const_mode::<0x5>();
+ assert_eq!(ctrl.mode(), 0x5);
+
+ // Test From conversion with =>
+ ctrl = ctrl.with_priority(Priority::High);
+ assert_eq!(ctrl.priority(), Priority::High);
+ assert_eq!(ctrl.priority_nibble(), 0x2); // High = 2 in bits 5:4
+
+ ctrl = ctrl.with_channel(0xAB);
+ assert_eq!(ctrl.channel(), 0xAB);
+
+ // Test overlapping fields
+ ctrl = ctrl.with_const_priority_nibble::<0xF>();
+ assert_eq!(ctrl.priority_nibble(), 0xF);
+ assert_eq!(ctrl.priority(), Priority::Critical); // bits 5:4 = 0x3
+
+ let ctrl2 = TestControlRegister::zeroed()
+ .with_enable(true)
+ .with_const_mode::<0x3>()
+ .with_priority(Priority::Medium)
+ .with_channel(0x42);
+
+ assert!(ctrl2.enable().into_bool());
+ assert_eq!(ctrl2.mode(), 0x3);
+ assert_eq!(ctrl2.priority(), Priority::Medium);
+ assert_eq!(ctrl2.channel(), 0x42);
+
+ let raw_value: u16 = 0x4217;
+ let ctrl3 = TestControlRegister::from_raw(raw_value);
+ assert_eq!(u16::from(ctrl3), raw_value);
+ assert!(ctrl3.enable().into_bool());
+ assert_eq!(ctrl3.priority(), Priority::Medium);
+ assert_eq!(ctrl3.priority_nibble(), 0x1);
+ assert_eq!(ctrl3.channel(), 0x42);
+ }
+
+ #[test]
+ fn test_u8_bitfield() {
+ let mut status = TestStatusRegister::zeroed();
+
+ assert!(!status.ready().into_bool());
+ assert!(!status.error().into_bool());
+ assert_eq!(status.state(), 0);
+ assert_eq!(status.reserved(), 0);
+ assert_eq!(status.full_byte(), 0);
+
+ status = status.with_ready(true);
+ assert!(status.ready().into_bool());
+ assert_eq!(status.full_byte(), 0x01);
+
+ status = status.with_error(true);
+ assert!(status.error().into_bool());
+ assert_eq!(status.full_byte(), 0x03);
+
+ status = status.with_const_state::<0x3>();
+ assert_eq!(status.state(), 0x3);
+ assert_eq!(status.full_byte(), 0x0F);
+
+ status = status.with_const_reserved::<0xA>();
+ assert_eq!(status.reserved(), 0xA);
+ assert_eq!(status.full_byte(), 0xAF);
+
+ // Test overlapping field
+ status = status.with_full_byte(0x55);
+ assert_eq!(status.full_byte(), 0x55);
+ assert!(status.ready().into_bool());
+ assert!(!status.error().into_bool());
+ assert_eq!(status.state(), 0x1);
+ assert_eq!(status.reserved(), 0x5);
+
+ let status2 = TestStatusRegister::zeroed()
+ .with_ready(true)
+ .with_const_state::<0x2>()
+ .with_const_reserved::<0x5>();
+
+ assert!(status2.ready().into_bool());
+ assert!(!status2.error().into_bool());
+ assert_eq!(status2.state(), 0x2);
+ assert_eq!(status2.reserved(), 0x5);
+ assert_eq!(status2.full_byte(), 0x59);
+
+ let raw_value: u8 = 0x59;
+ let status3 = TestStatusRegister::from_raw(raw_value);
+ assert_eq!(u8::from(status3), raw_value);
+ assert!(status3.ready().into_bool());
+ assert!(!status3.error().into_bool());
+ assert_eq!(status3.state(), 0x2);
+ assert_eq!(status3.reserved(), 0x5);
+ assert_eq!(status3.full_byte(), 0x59);
+
+ let status4 = TestStatusRegister::from_raw(0xFF);
+ assert!(status4.ready().into_bool());
+ assert!(status4.error().into_bool());
+ assert_eq!(status4.state(), 0x3);
+ assert_eq!(status4.reserved(), 0xF);
+ assert_eq!(status4.full_byte(), 0xFF);
+ }
+}
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 3/3] gpu: nova-core: switch to kernel bitfield macro
2026-04-09 14:58 [PATCH v2 0/3] rust: add `bitfield!` macro Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 1/3] rust: extract `bitfield!` macro from `register!` Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 2/3] rust: bitfield: Add KUNIT tests for bitfield Alexandre Courbot
@ 2026-04-09 14:58 ` Alexandre Courbot
2 siblings, 0 replies; 4+ messages in thread
From: Alexandre Courbot @ 2026-04-09 14:58 UTC (permalink / raw)
To: Joel Fernandes, Yury Norov, Miguel Ojeda, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Daniel Almeida, David Airlie,
Simona Vetter
Cc: John Hubbard, Alistair Popple, Timur Tabi, Zhi Wang,
Eliot Courtney, linux-kernel, rust-for-linux, driver-core,
dri-devel, Alexandre Courbot
Replace uses of the Nova-internal `bitfield!` macro by the kernel one,
and remove the now-unneeded local macro.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/gpu/nova-core/bitfield.rs | 329 -------------------------------------
drivers/gpu/nova-core/gsp/fw.rs | 15 +-
drivers/gpu/nova-core/nova_core.rs | 3 -
3 files changed, 8 insertions(+), 339 deletions(-)
diff --git a/drivers/gpu/nova-core/bitfield.rs b/drivers/gpu/nova-core/bitfield.rs
deleted file mode 100644
index 02efdcf78d89..000000000000
--- a/drivers/gpu/nova-core/bitfield.rs
+++ /dev/null
@@ -1,329 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! Bitfield library for Rust structures
-//!
-//! Support for defining bitfields in Rust structures. Also used by the [`register!`] macro.
-
-/// Defines a struct with accessors to access bits within an inner unsigned integer.
-///
-/// # Syntax
-///
-/// ```rust
-/// use nova_core::bitfield;
-///
-/// #[derive(Debug, Clone, Copy, Default)]
-/// enum Mode {
-/// #[default]
-/// Low = 0,
-/// High = 1,
-/// Auto = 2,
-/// }
-///
-/// impl TryFrom<u8> for Mode {
-/// type Error = u8;
-/// fn try_from(value: u8) -> Result<Self, Self::Error> {
-/// match value {
-/// 0 => Ok(Mode::Low),
-/// 1 => Ok(Mode::High),
-/// 2 => Ok(Mode::Auto),
-/// _ => Err(value),
-/// }
-/// }
-/// }
-///
-/// impl From<Mode> for u8 {
-/// fn from(mode: Mode) -> u8 {
-/// mode as u8
-/// }
-/// }
-///
-/// #[derive(Debug, Clone, Copy, Default)]
-/// enum State {
-/// #[default]
-/// Inactive = 0,
-/// Active = 1,
-/// }
-///
-/// impl From<bool> for State {
-/// fn from(value: bool) -> Self {
-/// if value { State::Active } else { State::Inactive }
-/// }
-/// }
-///
-/// impl From<State> for bool {
-/// fn from(state: State) -> bool {
-/// match state {
-/// State::Inactive => false,
-/// State::Active => true,
-/// }
-/// }
-/// }
-///
-/// bitfield! {
-/// pub struct ControlReg(u32) {
-/// 7:7 state as bool => State;
-/// 3:0 mode as u8 ?=> Mode;
-/// }
-/// }
-/// ```
-///
-/// This generates a struct with:
-/// - Field accessors: `mode()`, `state()`, etc.
-/// - Field setters: `set_mode()`, `set_state()`, etc. (supports chaining with builder pattern).
-/// Note that the compiler will error out if the size of the setter's arg exceeds the
-/// struct's storage size.
-/// - Debug and Default implementations.
-///
-/// Note: Field accessors and setters inherit the same visibility as the struct itself.
-/// In the example above, both `mode()` and `set_mode()` methods will be `pub`.
-///
-/// Fields are defined as follows:
-///
-/// - `as <type>` simply returns the field value casted to <type>, typically `u32`, `u16`, `u8` or
-/// `bool`. Note that `bool` fields must have a range of 1 bit.
-/// - `as <type> => <into_type>` calls `<into_type>`'s `From::<<type>>` implementation and returns
-/// the result.
-/// - `as <type> ?=> <try_into_type>` calls `<try_into_type>`'s `TryFrom::<<type>>` implementation
-/// and returns the result. This is useful with fields for which not all values are valid.
-macro_rules! bitfield {
- // Main entry point - defines the bitfield struct with fields
- ($vis:vis struct $name:ident($storage:ty) $(, $comment:literal)? { $($fields:tt)* }) => {
- bitfield!(@core $vis $name $storage $(, $comment)? { $($fields)* });
- };
-
- // All rules below are helpers.
-
- // Defines the wrapper `$name` type, as well as its relevant implementations (`Debug`,
- // `Default`, and conversion to the value type) and field accessor methods.
- (@core $vis:vis $name:ident $storage:ty $(, $comment:literal)? { $($fields:tt)* }) => {
- $(
- #[doc=$comment]
- )?
- #[repr(transparent)]
- #[derive(Clone, Copy)]
- $vis struct $name($storage);
-
- impl ::core::convert::From<$name> for $storage {
- fn from(val: $name) -> $storage {
- val.0
- }
- }
-
- bitfield!(@fields_dispatcher $vis $name $storage { $($fields)* });
- };
-
- // Captures the fields and passes them to all the implementers that require field information.
- //
- // Used to simplify the matching rules for implementers, so they don't need to match the entire
- // complex fields rule even though they only make use of part of it.
- (@fields_dispatcher $vis:vis $name:ident $storage:ty {
- $($hi:tt:$lo:tt $field:ident as $type:tt
- $(?=> $try_into_type:ty)?
- $(=> $into_type:ty)?
- $(, $comment:literal)?
- ;
- )*
- }
- ) => {
- bitfield!(@field_accessors $vis $name $storage {
- $(
- $hi:$lo $field as $type
- $(?=> $try_into_type)?
- $(=> $into_type)?
- $(, $comment)?
- ;
- )*
- });
- bitfield!(@debug $name { $($field;)* });
- bitfield!(@default $name { $($field;)* });
- };
-
- // Defines all the field getter/setter methods for `$name`.
- (
- @field_accessors $vis:vis $name:ident $storage:ty {
- $($hi:tt:$lo:tt $field:ident as $type:tt
- $(?=> $try_into_type:ty)?
- $(=> $into_type:ty)?
- $(, $comment:literal)?
- ;
- )*
- }
- ) => {
- $(
- bitfield!(@check_field_bounds $hi:$lo $field as $type);
- )*
-
- #[allow(dead_code)]
- impl $name {
- $(
- bitfield!(@field_accessor $vis $name $storage, $hi:$lo $field as $type
- $(?=> $try_into_type)?
- $(=> $into_type)?
- $(, $comment)?
- ;
- );
- )*
- }
- };
-
- // Boolean fields must have `$hi == $lo`.
- (@check_field_bounds $hi:tt:$lo:tt $field:ident as bool) => {
- #[allow(clippy::eq_op)]
- const _: () = {
- ::kernel::build_assert!(
- $hi == $lo,
- concat!("boolean field `", stringify!($field), "` covers more than one bit")
- );
- };
- };
-
- // Non-boolean fields must have `$hi >= $lo`.
- (@check_field_bounds $hi:tt:$lo:tt $field:ident as $type:tt) => {
- #[allow(clippy::eq_op)]
- const _: () = {
- ::kernel::build_assert!(
- $hi >= $lo,
- concat!("field `", stringify!($field), "`'s MSB is smaller than its LSB")
- );
- };
- };
-
- // Catches fields defined as `bool` and convert them into a boolean value.
- (
- @field_accessor $vis:vis $name:ident $storage:ty, $hi:tt:$lo:tt $field:ident as bool
- => $into_type:ty $(, $comment:literal)?;
- ) => {
- bitfield!(
- @leaf_accessor $vis $name $storage, $hi:$lo $field
- { |f| <$into_type>::from(f != 0) }
- bool $into_type => $into_type $(, $comment)?;
- );
- };
-
- // Shortcut for fields defined as `bool` without the `=>` syntax.
- (
- @field_accessor $vis:vis $name:ident $storage:ty, $hi:tt:$lo:tt $field:ident as bool
- $(, $comment:literal)?;
- ) => {
- bitfield!(
- @field_accessor $vis $name $storage, $hi:$lo $field as bool => bool $(, $comment)?;
- );
- };
-
- // Catches the `?=>` syntax for non-boolean fields.
- (
- @field_accessor $vis:vis $name:ident $storage:ty, $hi:tt:$lo:tt $field:ident as $type:tt
- ?=> $try_into_type:ty $(, $comment:literal)?;
- ) => {
- bitfield!(@leaf_accessor $vis $name $storage, $hi:$lo $field
- { |f| <$try_into_type>::try_from(f as $type) } $type $try_into_type =>
- ::core::result::Result<
- $try_into_type,
- <$try_into_type as ::core::convert::TryFrom<$type>>::Error
- >
- $(, $comment)?;);
- };
-
- // Catches the `=>` syntax for non-boolean fields.
- (
- @field_accessor $vis:vis $name:ident $storage:ty, $hi:tt:$lo:tt $field:ident as $type:tt
- => $into_type:ty $(, $comment:literal)?;
- ) => {
- bitfield!(@leaf_accessor $vis $name $storage, $hi:$lo $field
- { |f| <$into_type>::from(f as $type) } $type $into_type => $into_type $(, $comment)?;);
- };
-
- // Shortcut for non-boolean fields defined without the `=>` or `?=>` syntax.
- (
- @field_accessor $vis:vis $name:ident $storage:ty, $hi:tt:$lo:tt $field:ident as $type:tt
- $(, $comment:literal)?;
- ) => {
- bitfield!(
- @field_accessor $vis $name $storage, $hi:$lo $field as $type => $type $(, $comment)?;
- );
- };
-
- // Generates the accessor methods for a single field.
- (
- @leaf_accessor $vis:vis $name:ident $storage:ty, $hi:tt:$lo:tt $field:ident
- { $process:expr } $prim_type:tt $to_type:ty => $res_type:ty $(, $comment:literal)?;
- ) => {
- ::kernel::macros::paste!(
- const [<$field:upper _RANGE>]: ::core::ops::RangeInclusive<u8> = $lo..=$hi;
- const [<$field:upper _MASK>]: $storage = {
- // Generate mask for shifting
- match ::core::mem::size_of::<$storage>() {
- 1 => ::kernel::bits::genmask_u8($lo..=$hi) as $storage,
- 2 => ::kernel::bits::genmask_u16($lo..=$hi) as $storage,
- 4 => ::kernel::bits::genmask_u32($lo..=$hi) as $storage,
- 8 => ::kernel::bits::genmask_u64($lo..=$hi) as $storage,
- _ => ::kernel::build_error!("Unsupported storage type size")
- }
- };
- const [<$field:upper _SHIFT>]: u32 = $lo;
- );
-
- $(
- #[doc="Returns the value of this field:"]
- #[doc=$comment]
- )?
- #[inline(always)]
- $vis fn $field(self) -> $res_type {
- ::kernel::macros::paste!(
- const MASK: $storage = $name::[<$field:upper _MASK>];
- const SHIFT: u32 = $name::[<$field:upper _SHIFT>];
- );
- let field = ((self.0 & MASK) >> SHIFT);
-
- $process(field)
- }
-
- ::kernel::macros::paste!(
- $(
- #[doc="Sets the value of this field:"]
- #[doc=$comment]
- )?
- #[inline(always)]
- $vis fn [<set_ $field>](mut self, value: $to_type) -> Self {
- const MASK: $storage = $name::[<$field:upper _MASK>];
- const SHIFT: u32 = $name::[<$field:upper _SHIFT>];
- let value = ($storage::from($prim_type::from(value)) << SHIFT) & MASK;
- self.0 = (self.0 & !MASK) | value;
-
- self
- }
- );
- };
-
- // Generates the `Debug` implementation for `$name`.
- (@debug $name:ident { $($field:ident;)* }) => {
- impl ::kernel::fmt::Debug for $name {
- fn fmt(&self, f: &mut ::kernel::fmt::Formatter<'_>) -> ::kernel::fmt::Result {
- f.debug_struct(stringify!($name))
- .field("<raw>", &::kernel::prelude::fmt!("{:#x}", &self.0))
- $(
- .field(stringify!($field), &self.$field())
- )*
- .finish()
- }
- }
- };
-
- // Generates the `Default` implementation for `$name`.
- (@default $name:ident { $($field:ident;)* }) => {
- /// Returns a value for the bitfield where all fields are set to their default value.
- impl ::core::default::Default for $name {
- fn default() -> Self {
- let value = Self(Default::default());
-
- ::kernel::macros::paste!(
- $(
- let value = value.[<set_ $field>](Default::default());
- )*
- );
-
- value
- }
- }
- };
-}
diff --git a/drivers/gpu/nova-core/gsp/fw.rs b/drivers/gpu/nova-core/gsp/fw.rs
index 0c8a74f0e8ac..a7f75368c90e 100644
--- a/drivers/gpu/nova-core/gsp/fw.rs
+++ b/drivers/gpu/nova-core/gsp/fw.rs
@@ -9,6 +9,7 @@
use core::ops::Range;
use kernel::{
+ bitfield,
dma::Coherent,
prelude::*,
ptr::{
@@ -17,8 +18,8 @@
KnownSize, //
},
sizes::{
- SZ_128K,
- SZ_1M, //
+ SZ_128K, //
+ SZ_1M,
},
transmute::{
AsBytes,
@@ -728,8 +729,8 @@ unsafe impl AsBytes for MsgqRxHeader {}
bitfield! {
struct MsgHeaderVersion(u32) {
- 31:24 major as u8;
- 23:16 minor as u8;
+ 31:24 major;
+ 23:16 minor;
}
}
@@ -738,9 +739,9 @@ impl MsgHeaderVersion {
const MINOR_TOT: u8 = 0;
fn new() -> Self {
- Self::default()
- .set_major(Self::MAJOR_TOT)
- .set_minor(Self::MINOR_TOT)
+ Self::zeroed()
+ .with_major(Self::MAJOR_TOT)
+ .with_minor(Self::MINOR_TOT)
}
}
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index 04a1fa6b25f8..3a0c45481a92 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -10,9 +10,6 @@
InPlaceModule, //
};
-#[macro_use]
-mod bitfield;
-
mod driver;
mod falcon;
mod fb;
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
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Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-09 14:58 [PATCH v2 0/3] rust: add `bitfield!` macro Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 1/3] rust: extract `bitfield!` macro from `register!` Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 2/3] rust: bitfield: Add KUNIT tests for bitfield Alexandre Courbot
2026-04-09 14:58 ` [PATCH v2 3/3] gpu: nova-core: switch to kernel bitfield macro Alexandre Courbot
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