linux/rust/kernel/acpi.rs
FUJITA Tomonori 8d84b32075 rust: device_id: split out index support into a separate trait
Introduce a new trait `RawDeviceIdIndex`, which extends `RawDeviceId`
to provide support for device ID types that include an index or
context field (e.g., `driver_data`). This separates the concerns of
layout compatibility and index-based data embedding, and allows
`RawDeviceId` to be implemented for types that do not contain a
`driver_data` field. Several such structures are defined in
include/linux/mod_devicetable.h.

Refactor `IdArray::new()` into a generic `build()` function, which
takes an optional offset. Based on the presence of `RawDeviceIdIndex`,
index writing is conditionally enabled. A new `new_without_index()`
constructor is also provided for use cases where no index should be
written.

This refactoring is a preparation for enabling the PHY abstractions to
use the RawDeviceId trait.

The changes to acpi.rs and driver.rs were made by Danilo.

Reviewed-by: Trevor Gross <tmgross@umich.edu>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250711040947.1252162-2-fujita.tomonori@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-16 23:38:21 +02:00

70 lines
2.1 KiB
Rust

// SPDX-License-Identifier: GPL-2.0
//! Advanced Configuration and Power Interface abstractions.
use crate::{
bindings,
device_id::{RawDeviceId, RawDeviceIdIndex},
prelude::*,
};
/// IdTable type for ACPI drivers.
pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
/// An ACPI device id.
#[repr(transparent)]
#[derive(Clone, Copy)]
pub struct DeviceId(bindings::acpi_device_id);
// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `acpi_device_id` and does not add
// additional invariants, so it's safe to transmute to `RawType`.
unsafe impl RawDeviceId for DeviceId {
type RawType = bindings::acpi_device_id;
}
// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field.
unsafe impl RawDeviceIdIndex for DeviceId {
const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::acpi_device_id, driver_data);
fn index(&self) -> usize {
self.0.driver_data
}
}
impl DeviceId {
const ACPI_ID_LEN: usize = 16;
/// Create a new device id from an ACPI 'id' string.
#[inline(always)]
pub const fn new(id: &'static CStr) -> Self {
build_assert!(
id.len_with_nul() <= Self::ACPI_ID_LEN,
"ID exceeds 16 bytes"
);
let src = id.as_bytes_with_nul();
// Replace with `bindings::acpi_device_id::default()` once stabilized for `const`.
// SAFETY: FFI type is valid to be zero-initialized.
let mut acpi: bindings::acpi_device_id = unsafe { core::mem::zeroed() };
let mut i = 0;
while i < src.len() {
acpi.id[i] = src[i];
i += 1;
}
Self(acpi)
}
}
/// Create an ACPI `IdTable` with an "alias" for modpost.
#[macro_export]
macro_rules! acpi_device_table {
($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
const $table_name: $crate::device_id::IdArray<
$crate::acpi::DeviceId,
$id_info_type,
{ $table_data.len() },
> = $crate::device_id::IdArray::new($table_data);
$crate::module_device_table!("acpi", $module_table_name, $table_name);
};
}