// SPDX-License-Identifier: GPL-2.0 //! Abstractions for the platform bus.//!//! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h) use crate::{    acpi, bindings, container_of,    device::{self, Bound},    driver,    error::{from_result, to_result, Result},    io::{mem::IoRequest, Resource},    of,    prelude::*,    types::Opaque,    ThisModule,}; use core::{    marker::PhantomData,    ptr::{addr_of_mut, NonNull},}; /// An adapter for the registration of platform drivers.pub struct Adapter<T: Driver>(T); // SAFETY: A call to `unregister` for a given instance of `RegType` is guaranteed to be valid if// a preceding call to `register` has been successful.unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {    type RegType = bindings::platform_driver;     unsafe fn register(        pdrv: &Opaque<Self::RegType>,        name: &'static CStr,        module: &'static ThisModule,    ) -> Result {        let of_table = match T::OF_ID_TABLE {            Some(table) => table.as_ptr(),            None => core::ptr::null(),        };         let acpi_table = match T::ACPI_ID_TABLE {            Some(table) => table.as_ptr(),            None => core::ptr::null(),        };         // SAFETY: It's safe to set the fields of `struct platform_driver` on initialization.        unsafe {            (*pdrv.get()).driver.name = name.as_char_ptr();            (*pdrv.get()).probe = Some(Self::probe_callback);            (*pdrv.get()).remove = Some(Self::remove_callback);            (*pdrv.get()).driver.of_match_table = of_table;            (*pdrv.get()).driver.acpi_match_table = acpi_table;        }         // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.        to_result(unsafe { bindings::__platform_driver_register(pdrv.get(), module.0) })    }     unsafe fn unregister(pdrv: &Opaque<Self::RegType>) {        // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.        unsafe { bindings::platform_driver_unregister(pdrv.get()) };    }} impl<T: Driver + 'static> Adapter<T> {    extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> kernel::ffi::c_int {        // SAFETY: The platform bus only ever calls the probe callback with a valid pointer to a        // `struct platform_device`.        //        // INVARIANT: `pdev` is valid for the duration of `probe_callback()`.        let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal>>() };        let info = <Self as driver::Adapter>::id_info(pdev.as_ref());         from_result(|| {            let data = T::probe(pdev, info)?;             pdev.as_ref().set_drvdata(data);            Ok(0)        })    }     extern "C" fn remove_callback(pdev: *mut bindings::platform_device) {        // SAFETY: The platform bus only ever calls the remove callback with a valid pointer to a        // `struct platform_device`.        //        // INVARIANT: `pdev` is valid for the duration of `probe_callback()`.        let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal>>() };         // SAFETY: `remove_callback` is only ever called after a successful call to        // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called        // and stored a `Pin<KBox<T>>`.        let data = unsafe { pdev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };         T::unbind(pdev, data.as_ref());    }} impl<T: Driver + 'static> driver::Adapter for Adapter<T> {    type IdInfo = T::IdInfo;     fn of_id_table() -> Option<of::IdTable<Self::IdInfo>> {        T::OF_ID_TABLE    }     fn acpi_id_table() -> Option<acpi::IdTable<Self::IdInfo>> {        T::ACPI_ID_TABLE    }} /// Declares a kernel module that exposes a single platform driver.////// # Examples////// ```ignore/// kernel::module_platform_driver! {///     type: MyDriver,///     name: "Module name",///     authors: ["Author name"],///     description: "Description",///     license: "GPL v2",/// }/// ```#[macro_export]macro_rules! module_platform_driver {    ($($f:tt)*) => {        $crate::module_driver!(<T>, $crate::platform::Adapter<T>, { $($f)* });    };} /// The platform driver trait.////// Drivers must implement this trait in order to get a platform driver registered.////// # Examples//////```/// # use kernel::{acpi, bindings, c_str, device::Core, of, platform};////// struct MyDriver;////// kernel::of_device_table!(///     OF_TABLE,///     MODULE_OF_TABLE,///     <MyDriver as platform::Driver>::IdInfo,///     [///         (of::DeviceId::new(c_str!("test,device")), ())///     ]/// );////// kernel::acpi_device_table!(///     ACPI_TABLE,///     MODULE_ACPI_TABLE,///     <MyDriver as platform::Driver>::IdInfo,///     [///         (acpi::DeviceId::new(c_str!("LNUXBEEF")), ())///     ]/// );////// impl platform::Driver for MyDriver {///     type IdInfo = ();///     const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);///     const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);//////     fn probe(///         _pdev: &platform::Device<Core>,///         _id_info: Option<&Self::IdInfo>,///     ) -> Result<Pin<KBox<Self>>> {///         Err(ENODEV)///     }/// }///```pub trait Driver: Send {    /// The type holding driver private data about each device id supported by the driver.    // TODO: Use associated_type_defaults once stabilized:    //    // ```    // type IdInfo: 'static = ();    // ```    type IdInfo: 'static;     /// The table of OF device ids supported by the driver.    const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = None;     /// The table of ACPI device ids supported by the driver.    const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = None;     /// Platform driver probe.    ///    /// Called when a new platform device is added or discovered.    /// Implementers should attempt to initialize the device here.    fn probe(dev: &Device<device::Core>, id_info: Option<&Self::IdInfo>)        -> Result<Pin<KBox<Self>>>;     /// Platform driver unbind.    ///    /// Called when a [`Device`] is unbound from its bound [`Driver`]. Implementing this callback    /// is optional.    ///    /// This callback serves as a place for drivers to perform teardown operations that require a    /// `&Device<Core>` or `&Device<Bound>` reference. For instance, drivers may try to perform I/O    /// operations to gracefully tear down the device.    ///    /// Otherwise, release operations for driver resources should be performed in `Self::drop`.    fn unbind(dev: &Device<device::Core>, this: Pin<&Self>) {        let _ = (dev, this);    }} /// The platform device representation.////// This structure represents the Rust abstraction for a C `struct platform_device`. The/// implementation abstracts the usage of an already existing C `struct platform_device` within Rust/// code that we get passed from the C side.////// # Invariants////// A [`Device`] instance represents a valid `struct platform_device` created by the C portion of/// the kernel.#[repr(transparent)]pub struct Device<Ctx: device::DeviceContext = device::Normal>(    Opaque<bindings::platform_device>,    PhantomData<Ctx>,); impl<Ctx: device::DeviceContext> Device<Ctx> {    fn as_raw(&self) -> *mut bindings::platform_device {        self.0.get()    }     /// Returns the resource at `index`, if any.    pub fn resource_by_index(&self, index: u32) -> Option<&Resource> {        // SAFETY: `self.as_raw()` returns a valid pointer to a `struct platform_device`.        let resource = unsafe {            bindings::platform_get_resource(self.as_raw(), bindings::IORESOURCE_MEM, index)        };         if resource.is_null() {            return None;        }         // SAFETY: `resource` is a valid pointer to a `struct resource` as        // returned by `platform_get_resource`.        Some(unsafe { Resource::from_raw(resource) })    }     /// Returns the resource with a given `name`, if any.    pub fn resource_by_name(&self, name: &CStr) -> Option<&Resource> {        // SAFETY: `self.as_raw()` returns a valid pointer to a `struct        // platform_device` and `name` points to a valid C string.        let resource = unsafe {            bindings::platform_get_resource_byname(                self.as_raw(),                bindings::IORESOURCE_MEM,                name.as_char_ptr(),            )        };         if resource.is_null() {            return None;        }         // SAFETY: `resource` is a valid pointer to a `struct resource` as        // returned by `platform_get_resource`.        Some(unsafe { Resource::from_raw(resource) })    }} impl Device<Bound> {    /// Returns an `IoRequest` for the resource at `index`, if any.    pub fn io_request_by_index(&self, index: u32) -> Option<IoRequest<'_>> {        self.resource_by_index(index)            // SAFETY: `resource` is a valid resource for `&self` during the            // lifetime of the `IoRequest`.            .map(|resource| unsafe { IoRequest::new(self.as_ref(), resource) })    }     /// Returns an `IoRequest` for the resource with a given `name`, if any.    pub fn io_request_by_name(&self, name: &CStr) -> Option<IoRequest<'_>> {        self.resource_by_name(name)            // SAFETY: `resource` is a valid resource for `&self` during the            // lifetime of the `IoRequest`.            .map(|resource| unsafe { IoRequest::new(self.as_ref(), resource) })    }} // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic// argument.kernel::impl_device_context_deref!(unsafe { Device });kernel::impl_device_context_into_aref!(Device); impl crate::dma::Device for Device<device::Core> {} // SAFETY: Instances of `Device` are always reference-counted.unsafe impl crate::types::AlwaysRefCounted for Device {    fn inc_ref(&self) {        // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.        unsafe { bindings::get_device(self.as_ref().as_raw()) };    }     unsafe fn dec_ref(obj: NonNull<Self>) {        // SAFETY: The safety requirements guarantee that the refcount is non-zero.        unsafe { bindings::platform_device_put(obj.cast().as_ptr()) }    }} impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {    fn as_ref(&self) -> &device::Device<Ctx> {        // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid        // `struct platform_device`.        let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) };         // SAFETY: `dev` points to a valid `struct device`.        unsafe { device::Device::from_raw(dev) }    }} impl<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &Device<Ctx> {    type Error = kernel::error::Error;     fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> {        // SAFETY: By the type invariant of `Device`, `dev.as_raw()` is a valid pointer to a        // `struct device`.        if !unsafe { bindings::dev_is_platform(dev.as_raw()) } {            return Err(EINVAL);        }         // SAFETY: We've just verified that the bus type of `dev` equals        // `bindings::platform_bus_type`, hence `dev` must be embedded in a valid        // `struct platform_device` as guaranteed by the corresponding C code.        let pdev = unsafe { container_of!(dev.as_raw(), bindings::platform_device, dev) };         // SAFETY: `pdev` is a valid pointer to a `struct platform_device`.        Ok(unsafe { &*pdev.cast() })    }} // SAFETY: A `Device` is always reference-counted and can be released from any thread.unsafe impl Send for Device {} // SAFETY: `Device` can be shared among threads because all methods of `Device`// (i.e. `Device<Normal>) are thread safe.unsafe impl Sync for Device {}