kernel/
acpi.rs

1// SPDX-License-Identifier: GPL-2.0
2
3//! Advanced Configuration and Power Interface abstractions.
4
5use crate::{
6    bindings,
7    device_id::{RawDeviceId, RawDeviceIdIndex},
8    prelude::*,
9};
10
11/// IdTable type for ACPI drivers.
12pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
13
14/// An ACPI device id.
15#[repr(transparent)]
16#[derive(Clone, Copy)]
17pub struct DeviceId(bindings::acpi_device_id);
18
19// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `acpi_device_id` and does not add
20// additional invariants, so it's safe to transmute to `RawType`.
21unsafe impl RawDeviceId for DeviceId {
22    type RawType = bindings::acpi_device_id;
23}
24
25// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field.
26unsafe impl RawDeviceIdIndex for DeviceId {
27    const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::acpi_device_id, driver_data);
28
29    fn index(&self) -> usize {
30        self.0.driver_data
31    }
32}
33
34impl DeviceId {
35    const ACPI_ID_LEN: usize = 16;
36
37    /// Create a new device id from an ACPI 'id' string.
38    #[inline(always)]
39    pub const fn new(id: &'static CStr) -> Self {
40        build_assert!(
41            id.len_with_nul() <= Self::ACPI_ID_LEN,
42            "ID exceeds 16 bytes"
43        );
44        let src = id.as_bytes_with_nul();
45        // Replace with `bindings::acpi_device_id::default()` once stabilized for `const`.
46        // SAFETY: FFI type is valid to be zero-initialized.
47        let mut acpi: bindings::acpi_device_id = unsafe { core::mem::zeroed() };
48        let mut i = 0;
49        while i < src.len() {
50            acpi.id[i] = src[i];
51            i += 1;
52        }
53
54        Self(acpi)
55    }
56}
57
58/// Create an ACPI `IdTable` with an "alias" for modpost.
59#[macro_export]
60macro_rules! acpi_device_table {
61    ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
62        const $table_name: $crate::device_id::IdArray<
63            $crate::acpi::DeviceId,
64            $id_info_type,
65            { $table_data.len() },
66        > = $crate::device_id::IdArray::new($table_data);
67
68        $crate::module_device_table!("acpi", $module_table_name, $table_name);
69    };
70}
kernel/acpi.rs

kernel/
acpi.rs
