rust: of: add `of::DeviceId` abstraction

`of::DeviceId` is an abstraction around `struct of_device_id`.

This is used by subsequent patches, in particular the platform bus
abstractions, to create OF device ID tables.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Tested-by: Fabien Parent <fabien.parent@linaro.org>
Link: https://lore.kernel.org/r/20241219170425.12036-13-dakr@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

authored by

Danilo Krummrich and committed by

Greg Kroah-Hartman 2 years ago bbe3b4d1 685376d1

+62

3 changed files

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MAINTAINERS

rust

kernel

lib.rs

of.rs

MAINTAINERS

··· 17505 17505 F: Documentation/ABI/testing/sysfs-firmware-ofw 17506 17506 F: drivers/of/ 17507 17507 F: include/linux/of*.h 17508 + F: rust/kernel/of.rs 17508 17509 F: scripts/dtc/ 17509 17510 F: tools/testing/selftests/dt/ 17510 17511 K: of_overlay_notifier_

rust/kernel/lib.rs

··· 56 56 pub mod miscdevice; 57 57 #[cfg(CONFIG_NET)] 58 58 pub mod net; 59 + pub mod of; 59 60 pub mod page; 60 61 pub mod pid_namespace; 61 62 pub mod prelude;

+60

rust/kernel/of.rs

··· 1 + // SPDX-License-Identifier: GPL-2.0 2 + 3 + //! Device Tree / Open Firmware abstractions. 4 + 5 + use crate::{bindings, device_id::RawDeviceId, prelude::*}; 6 + 7 + /// IdTable type for OF drivers. 8 + pub 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)] 13 + pub 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. 19 + unsafe 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 _ 26 + } 27 + } 28 + 29 + impl 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 `clone_from_slice` once the corresponding types do match. 38 + let mut i = 0; 39 + while i < src.len() { 40 + of.compatible[i] = src[i] as _; 41 + i += 1; 42 + } 43 + 44 + Self(of) 45 + } 46 + } 47 + 48 + /// Create an OF `IdTable` with an "alias" for modpost. 49 + #[macro_export] 50 + macro_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 + }

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