kernel/
of.rs

1// SPDX-License-Identifier: GPL-2.0
2
3//! Device Tree / Open Firmware abstractions.
4
5use crate::{bindings, device_id::RawDeviceId, prelude::*};
6
7/// IdTable type for OF drivers.
8pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
9
10/// An open firmware device id.
11#[repr(transparent)]
12#[derive(Clone, Copy)]
13pub struct DeviceId(bindings::of_device_id);
14
15// SAFETY:
16// * `DeviceId` is a `#[repr(transparent)]` wrapper of `struct of_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::of_device_id;
21
22    const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::of_device_id, data);
23
24    fn index(&self) -> usize {
25        self.0.data as usize
26    }
27}
28
29impl DeviceId {
30    /// Create a new device id from an OF 'compatible' string.
31    pub const fn new(compatible: &'static CStr) -> Self {
32        let src = compatible.as_bytes_with_nul();
33        // Replace with `bindings::of_device_id::default()` once stabilized for `const`.
34        // SAFETY: FFI type is valid to be zero-initialized.
35        let mut of: bindings::of_device_id = unsafe { core::mem::zeroed() };
36
37        // TODO: Use `copy_from_slice` once stabilized for `const`.
38        let mut i = 0;
39        while i < src.len() {
40            of.compatible[i] = src[i];
41            i += 1;
42        }
43
44        Self(of)
45    }
46}
47
48/// Create an OF `IdTable` with an "alias" for modpost.
49#[macro_export]
50macro_rules! of_device_table {
51    ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
52        const $table_name: $crate::device_id::IdArray<
53            $crate::of::DeviceId,
54            $id_info_type,
55            { $table_data.len() },
56        > = $crate::device_id::IdArray::new($table_data);
57
58        $crate::module_device_table!("of", $module_table_name, $table_name);
59    };
60}
kernel/of.rs

kernel/
of.rs
