1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Device Tree / Open Firmware abstractions. 4 5 use crate::{ 6 bindings, 7 device_id::{RawDeviceId, RawDeviceIdIndex}, 8 prelude::*, 9 }; 10 11 /// IdTable type for OF drivers. 12 pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; 13 14 /// An open firmware device id. 15 #[repr(transparent)] 16 #[derive(Clone, Copy)] 17 pub struct DeviceId(bindings::of_device_id); 18 19 // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct of_device_id` and 20 // does not add additional invariants, so it's safe to transmute to `RawType`. 21 unsafe impl RawDeviceId for DeviceId { 22 type RawType = bindings::of_device_id; 23 } 24 25 // SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `data` field. 26 unsafe impl RawDeviceIdIndex for DeviceId { 27 const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::of_device_id, data); 28 } 29 30 impl DeviceId { 31 /// Create a new device id from an OF 'compatible' string. 32 pub const fn new(compatible: &'static CStr) -> Self { 33 let src = compatible.to_bytes_with_nul(); 34 // Replace with `bindings::of_device_id::default()` once stabilized for `const`. 35 // SAFETY: FFI type is valid to be zero-initialized. 36 let mut of: bindings::of_device_id = unsafe { core::mem::zeroed() }; 37 38 // TODO: Use `copy_from_slice` once stabilized for `const`. 39 let mut i = 0; 40 while i < src.len() { 41 of.compatible[i] = src[i]; 42 i += 1; 43 } 44 45 Self(of) 46 } 47 } 48 49 /// Create an OF `IdTable` with an "alias" for modpost. 50 #[macro_export] 51 macro_rules! of_device_table { 52 ($($tt:tt)*) => { 53 $crate::module_device_table!("of", $crate::of::DeviceId, $($tt)*); 54 }; 55 } 56