// SPDX-License-Identifier: GPL-2.0 //! Generic support for drivers of different buses (e.g., PCI, Platform, Amba, etc.).//!//! Each bus / subsystem is expected to implement [`RegistrationOps`], which allows drivers to//! register using the [`Registration`] class. use crate::error::{Error, Result};use crate::{device, init::PinInit, of, str::CStr, try_pin_init, types::Opaque, ThisModule};use core::pin::Pin;use macros::{pin_data, pinned_drop}; /// The [`RegistrationOps`] trait serves as generic interface for subsystems (e.g., PCI, Platform,/// Amba, etc.) to provide the corresponding subsystem specific implementation to register //// unregister a driver of the particular type (`RegType`).////// For instance, the PCI subsystem would set `RegType` to `bindings::pci_driver` and call/// `bindings::__pci_register_driver` from `RegistrationOps::register` and/// `bindings::pci_unregister_driver` from `RegistrationOps::unregister`.////// # Safety////// A call to [`RegistrationOps::unregister`] for a given instance of `RegType` is only valid if a/// preceding call to [`RegistrationOps::register`] has been successful.pub unsafe trait RegistrationOps { /// The type that holds information about the registration. This is typically a struct defined /// by the C portion of the kernel. type RegType: Default; /// Registers a driver. /// /// # Safety /// /// On success, `reg` must remain pinned and valid until the matching call to /// [`RegistrationOps::unregister`]. unsafe fn register( reg: &Opaque<Self::RegType>, name: &'static CStr, module: &'static ThisModule, ) -> Result; /// Unregisters a driver previously registered with [`RegistrationOps::register`]. /// /// # Safety /// /// Must only be called after a preceding successful call to [`RegistrationOps::register`] for /// the same `reg`. unsafe fn unregister(reg: &Opaque<Self::RegType>);} /// A [`Registration`] is a generic type that represents the registration of some driver type (e.g./// `bindings::pci_driver`). Therefore a [`Registration`] must be initialized with a type that/// implements the [`RegistrationOps`] trait, such that the generic `T::register` and/// `T::unregister` calls result in the subsystem specific registration calls.//////Once the `Registration` structure is dropped, the driver is unregistered.#[pin_data(PinnedDrop)]pub struct Registration<T: RegistrationOps> { #[pin] reg: Opaque<T::RegType>,} // SAFETY: `Registration` has no fields or methods accessible via `&Registration`, so it is safe to// share references to it with multiple threads as nothing can be done.unsafe impl<T: RegistrationOps> Sync for Registration<T> {} // SAFETY: Both registration and unregistration are implemented in C and safe to be performed from// any thread, so `Registration` is `Send`.unsafe impl<T: RegistrationOps> Send for Registration<T> {} impl<T: RegistrationOps> Registration<T> { /// Creates a new instance of the registration object. pub fn new(name: &'static CStr, module: &'static ThisModule) -> impl PinInit<Self, Error> { try_pin_init!(Self { reg <- Opaque::try_ffi_init(|ptr: *mut T::RegType| { // SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write. unsafe { ptr.write(T::RegType::default()) }; // SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write, and it has // just been initialised above, so it's also valid for read. let drv = unsafe { &*(ptr as *const Opaque<T::RegType>) }; // SAFETY: `drv` is guaranteed to be pinned until `T::unregister`. unsafe { T::register(drv, name, module) } }), }) }} #[pinned_drop]impl<T: RegistrationOps> PinnedDrop for Registration<T> { fn drop(self: Pin<&mut Self>) { // SAFETY: The existence of `self` guarantees that `self.reg` has previously been // successfully registered with `T::register` unsafe { T::unregister(&self.reg) }; }} /// Declares a kernel module that exposes a single driver.////// It is meant to be used as a helper by other subsystems so they can more easily expose their own/// macros.#[macro_export]macro_rules! module_driver { (<$gen_type:ident>, $driver_ops:ty, { type: $type:ty, $($f:tt)* }) => { type Ops<$gen_type> = $driver_ops; #[$crate::prelude::pin_data] struct DriverModule { #[pin] _driver: $crate::driver::Registration<Ops<$type>>, } impl $crate::InPlaceModule for DriverModule { fn init( module: &'static $crate::ThisModule ) -> impl $crate::init::PinInit<Self, $crate::error::Error> { $crate::try_pin_init!(Self { _driver <- $crate::driver::Registration::new( <Self as $crate::ModuleMetadata>::NAME, module, ), }) } } $crate::prelude::module! { type: DriverModule, $($f)* } }} /// The bus independent adapter to match a drivers and a devices.////// This trait should be implemented by the bus specific adapter, which represents the connection/// of a device and a driver.////// It provides bus independent functions for device / driver interactions.pub trait Adapter { /// The type holding driver private data about each device id supported by the driver. type IdInfo: 'static; /// The [`of::IdTable`] of the corresponding driver. fn of_id_table() -> Option<of::IdTable<Self::IdInfo>>; /// Returns the driver's private data from the matching entry in the [`of::IdTable`], if any. /// /// If this returns `None`, it means there is no match with an entry in the [`of::IdTable`]. #[cfg(CONFIG_OF)] fn of_id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> { let table = Self::of_id_table()?; // SAFETY: // - `table` has static lifetime, hence it's valid for read, // - `dev` is guaranteed to be valid while it's alive, and so is `pdev.as_ref().as_raw()`. let raw_id = unsafe { bindings::of_match_device(table.as_ptr(), dev.as_raw()) }; if raw_id.is_null() { None } else { // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct of_device_id` and // does not add additional invariants, so it's safe to transmute. let id = unsafe { &*raw_id.cast::<of::DeviceId>() }; Some(table.info(<of::DeviceId as crate::device_id::RawDeviceId>::index(id))) } } #[cfg(not(CONFIG_OF))] #[allow(missing_docs)] fn of_id_info(_dev: &device::Device) -> Option<&'static Self::IdInfo> { None } /// Returns the driver's private data from the matching entry of any of the ID tables, if any. /// /// If this returns `None`, it means that there is no match in any of the ID tables directly /// associated with a [`device::Device`]. fn id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> { let id = Self::of_id_info(dev); if id.is_some() { return id; } None }}
// SPDX-License-Identifier: GPL-2.0
//! Generic support for drivers of different buses (e.g., PCI, Platform, Amba, etc.).
//!
//! Each bus / subsystem is expected to implement [`RegistrationOps`], which allows drivers to
//! register using the [`Registration`] class.
use crate::error::{Error, Result};
use crate::{device, init::PinInit, of, str::CStr, try_pin_init, types::Opaque, ThisModule};
use core::pin::Pin;
use macros::{pin_data, pinned_drop};
/// The [`RegistrationOps`] trait serves as generic interface for subsystems (e.g., PCI, Platform,
/// Amba, etc.) to provide the corresponding subsystem specific implementation to register /
/// unregister a driver of the particular type (`RegType`).
///
/// For instance, the PCI subsystem would set `RegType` to `bindings::pci_driver` and call
/// `bindings::__pci_register_driver` from `RegistrationOps::register` and
/// `bindings::pci_unregister_driver` from `RegistrationOps::unregister`.
///
/// # Safety
///
/// A call to [`RegistrationOps::unregister`] for a given instance of `RegType` is only valid if a
/// preceding call to [`RegistrationOps::register`] has been successful.
pub unsafe trait RegistrationOps {
/// The type that holds information about the registration. This is typically a struct defined
/// by the C portion of the kernel.
type RegType: Default;
/// Registers a driver.
///
/// # Safety
///
/// On success, `reg` must remain pinned and valid until the matching call to
/// [`RegistrationOps::unregister`].
unsafe fn register(
reg: &Opaque<Self::RegType>,
name: &'static CStr,
module: &'static ThisModule,
) -> Result;
/// Unregisters a driver previously registered with [`RegistrationOps::register`].
///
/// # Safety
///
/// Must only be called after a preceding successful call to [`RegistrationOps::register`] for
/// the same `reg`.
unsafe fn unregister(reg: &Opaque<Self::RegType>);
}
/// A [`Registration`] is a generic type that represents the registration of some driver type (e.g.
/// `bindings::pci_driver`). Therefore a [`Registration`] must be initialized with a type that
/// implements the [`RegistrationOps`] trait, such that the generic `T::register` and
/// `T::unregister` calls result in the subsystem specific registration calls.
///
///Once the `Registration` structure is dropped, the driver is unregistered.
#[pin_data(PinnedDrop)]
pub struct Registration<T: RegistrationOps> {
#[pin]
reg: Opaque<T::RegType>,
}
// SAFETY: `Registration` has no fields or methods accessible via `&Registration`, so it is safe to
// share references to it with multiple threads as nothing can be done.
unsafe impl<T: RegistrationOps> Sync for Registration<T> {}
// SAFETY: Both registration and unregistration are implemented in C and safe to be performed from
// any thread, so `Registration` is `Send`.
unsafe impl<T: RegistrationOps> Send for Registration<T> {}
impl<T: RegistrationOps> Registration<T> {
/// Creates a new instance of the registration object.
pub fn new(name: &'static CStr, module: &'static ThisModule) -> impl PinInit<Self, Error> {
try_pin_init!(Self {
reg <- Opaque::try_ffi_init(|ptr: *mut T::RegType| {
// SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write.
unsafe { ptr.write(T::RegType::default()) };
// SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write, and it has
// just been initialised above, so it's also valid for read.
let drv = unsafe { &*(ptr as *const Opaque<T::RegType>) };
// SAFETY: `drv` is guaranteed to be pinned until `T::unregister`.
unsafe { T::register(drv, name, module) }
}),
})
}
}
#[pinned_drop]
impl<T: RegistrationOps> PinnedDrop for Registration<T> {
fn drop(self: Pin<&mut Self>) {
// SAFETY: The existence of `self` guarantees that `self.reg` has previously been
// successfully registered with `T::register`
unsafe { T::unregister(&self.reg) };
}
}
/// Declares a kernel module that exposes a single driver.
///
/// It is meant to be used as a helper by other subsystems so they can more easily expose their own
/// macros.
#[macro_export]
macro_rules! module_driver {
(<$gen_type:ident>, $driver_ops:ty, { type: $type:ty, $($f:tt)* }) => {
type Ops<$gen_type> = $driver_ops;
#[$crate::prelude::pin_data]
struct DriverModule {
#[pin]
_driver: $crate::driver::Registration<Ops<$type>>,
}
impl $crate::InPlaceModule for DriverModule {
fn init(
module: &'static $crate::ThisModule
) -> impl $crate::init::PinInit<Self, $crate::error::Error> {
$crate::try_pin_init!(Self {
_driver <- $crate::driver::Registration::new(
<Self as $crate::ModuleMetadata>::NAME,
module,
),
})
}
}
$crate::prelude::module! {
type: DriverModule,
$($f)*
}
}
}
/// The bus independent adapter to match a drivers and a devices.
///
/// This trait should be implemented by the bus specific adapter, which represents the connection
/// of a device and a driver.
///
/// It provides bus independent functions for device / driver interactions.
pub trait Adapter {
/// The type holding driver private data about each device id supported by the driver.
type IdInfo: 'static;
/// The [`of::IdTable`] of the corresponding driver.
fn of_id_table() -> Option<of::IdTable<Self::IdInfo>>;
/// Returns the driver's private data from the matching entry in the [`of::IdTable`], if any.
///
/// If this returns `None`, it means there is no match with an entry in the [`of::IdTable`].
#[cfg(CONFIG_OF)]
fn of_id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> {
let table = Self::of_id_table()?;
// SAFETY:
// - `table` has static lifetime, hence it's valid for read,
// - `dev` is guaranteed to be valid while it's alive, and so is `pdev.as_ref().as_raw()`.
let raw_id = unsafe { bindings::of_match_device(table.as_ptr(), dev.as_raw()) };
if raw_id.is_null() {
None
} else {
// SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct of_device_id` and
// does not add additional invariants, so it's safe to transmute.
let id = unsafe { &*raw_id.cast::<of::DeviceId>() };
Some(table.info(<of::DeviceId as crate::device_id::RawDeviceId>::index(id)))
}
}
#[cfg(not(CONFIG_OF))]
#[allow(missing_docs)]
fn of_id_info(_dev: &device::Device) -> Option<&'static Self::IdInfo> {
None
}
/// Returns the driver's private data from the matching entry of any of the ID tables, if any.
///
/// If this returns `None`, it means that there is no match in any of the ID tables directly
/// associated with a [`device::Device`].
fn id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> {
let id = Self::of_id_info(dev);
if id.is_some() {
return id;
}
None
}
}