kernel/
acpi.rs

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

kernel/
acpi.rs
