[PATCH v2 3/3] gpu: nova-core: switch to kernel bitfield macro

Alexandre Courbot
2026-04-09T14:59:18Z

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