Commit a74931eb authored by Igor Korotin's avatar Igor Korotin Committed by Danilo Krummrich
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rust: acpi: add `acpi::DeviceId` abstraction 



`acpi::DeviceId` is an abstraction around `struct acpi_device_id`.

Enable drivers to build ACPI device ID tables, to be consumed by the
corresponding bus abstractions, such as platform or I2C.

Signed-off-by: default avatarIgor Korotin <igor.korotin.linux@gmail.com>
Acked-by: default avatarRafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20250620152425.285683-1-igor.korotin.linux@gmail.com


[ Always inline DeviceId::new() and use &'static CStr; slightly reword
  commit message. - Danilo ]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 9da36b9f

MAINTAINERS

+1 −0
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@@ -302,6 +302,7 @@ F: include/linux/acpi.h 
F:	include/linux/fwnode.h

F:	include/linux/fw_table.h

F:	lib/fw_table.c

F:	rust/kernel/acpi.rs

F:	tools/power/acpi/









ACPI APEI
































rust/kernel/acpi.rs
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// SPDX-License-Identifier: GPL-2.0



















//! Advanced Configuration and Power Interface abstractions.



















use crate::{bindings, device_id::RawDeviceId, prelude::*};



















/// IdTable type for ACPI drivers.









pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;



















/// An ACPI device id.









#[repr(transparent)]









#[derive(Clone, Copy)]









pub struct DeviceId(bindings::acpi_device_id);



















// SAFETY:









// * `DeviceId` is a `#[repr(transparent)` wrapper of `struct acpi_device_id` and does not add









//   additional invariants, so it's safe to transmute to `RawType`.









// * `DRIVER_DATA_OFFSET` is the offset to the `data` field.









unsafe impl RawDeviceId for DeviceId {









    type RawType = bindings::acpi_device_id;



















    const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::acpi_device_id, driver_data);



















    fn index(&self) -> usize {









        self.0.driver_data as _









    }









}



















impl DeviceId {









    const ACPI_ID_LEN: usize = 16;



















    /// Create a new device id from an ACPI 'id' string.









    #[inline(always)]









    pub const fn new(id: &'static CStr) -> Self {









        build_assert!(









            id.len_with_nul() <= Self::ACPI_ID_LEN,









            "ID exceeds 16 bytes"









        );









        let src = id.as_bytes_with_nul();









        // Replace with `bindings::acpi_device_id::default()` once stabilized for `const`.









        // SAFETY: FFI type is valid to be zero-initialized.









        let mut acpi: bindings::acpi_device_id = unsafe { core::mem::zeroed() };









        let mut i = 0;









        while i < src.len() {









            acpi.id[i] = src[i];









            i += 1;









        }



















        Self(acpi)









    }









}



















/// Create an ACPI `IdTable` with an "alias" for modpost.









#[macro_export]









macro_rules! acpi_device_table {









    ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {









        const $table_name: $crate::device_id::IdArray<









            $crate::acpi::DeviceId,









            $id_info_type,









            { $table_data.len() },









        > = $crate::device_id::IdArray::new($table_data);



















        $crate::module_device_table!("acpi", $module_table_name, $table_name);









    };









}
























rust/kernel/lib.rs



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@@ -51,6 +51,7 @@

















pub use ffi;



















pub mod acpi;









pub mod alloc;









#[cfg(CONFIG_AUXILIARY_BUS)]









pub mod auxiliary;