1 files changed, 146 insertions, 45 deletions

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 4917cb34e2fe..8f028c76f9fa 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -5,18 +5,19 @@
 //! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h)
 
 use crate::{
-    bindings, device, driver,
-    error::{to_result, Result},
+    acpi, bindings, container_of,
+    device::{self, Bound},
+    driver,
+    error::{from_result, to_result, Result},
+    io::{mem::IoRequest, Resource},
     of,
     prelude::*,
-    str::CStr,
-    types::{ARef, ForeignOwnable, Opaque},
+    types::Opaque,
     ThisModule,
 };
 
 use core::{
     marker::PhantomData,
-    ops::Deref,
     ptr::{addr_of_mut, NonNull},
 };
 
@@ -38,12 +39,18 @@ unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
             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`.
@@ -62,30 +69,30 @@ impl<T: Driver + 'static> Adapter<T> {
         // `struct platform_device`.
         //
         // INVARIANT: `pdev` is valid for the duration of `probe_callback()`.
-        let pdev = unsafe { &*pdev.cast::<Device<device::Core>>() };
-
+        let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal>>() };
         let info = <Self as driver::Adapter>::id_info(pdev.as_ref());
-        match T::probe(pdev, info) {
-            Ok(data) => {
-                // Let the `struct platform_device` own a reference of the driver's private data.
-                // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a
-                // `struct platform_device`.
-                unsafe { bindings::platform_set_drvdata(pdev.as_raw(), data.into_foreign() as _) };
-            }
-            Err(err) => return Error::to_errno(err),
-        }
 
-        0
+        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: `pdev` is a valid pointer to a `struct platform_device`.
-        let ptr = unsafe { bindings::platform_get_drvdata(pdev) };
+        // 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 `ptr` points to a valid and initialized
-        // `KBox<T>` pointer created through `KBox::into_foreign`.
-        let _ = unsafe { KBox::<T>::from_foreign(ptr) };
+        // `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());
     }
 }
 
@@ -95,6 +102,10 @@ impl<T: Driver + 'static> driver::Adapter for Adapter<T> {
     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.
@@ -121,10 +132,10 @@ macro_rules! module_platform_driver {
 ///
 /// Drivers must implement this trait in order to get a platform driver registered.
 ///
-/// # Example
+/// # Examples
 ///
 ///```
-/// # use kernel::{bindings, c_str, device::Core, of, platform};
+/// # use kernel::{acpi, bindings, c_str, device::Core, of, platform};
 ///
 /// struct MyDriver;
 ///
@@ -137,9 +148,19 @@ macro_rules! module_platform_driver {
 ///     ]
 /// );
 ///
+/// 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>,
@@ -151,14 +172,18 @@ macro_rules! module_platform_driver {
 ///```
 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 = ();
+    // 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>>;
+    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.
     ///
@@ -166,6 +191,20 @@ pub trait Driver: Send {
     /// 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.
@@ -184,32 +223,74 @@ pub struct Device<Ctx: device::DeviceContext = device::Normal>(
     PhantomData<Ctx>,
 );
 
-impl Device {
+impl<Ctx: device::DeviceContext> Device<Ctx> {
     fn as_raw(&self) -> *mut bindings::platform_device {
         self.0.get()
     }
-}
 
-impl Deref for Device<device::Core> {
-    type Target = Device;
+    /// 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) })
+    }
 
-    fn deref(&self) -> &Self::Target {
-        let ptr: *const Self = self;
+    /// 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(),
+            )
+        };
 
-        // CAST: `Device<Ctx>` is a transparent wrapper of `Opaque<bindings::platform_device>`.
-        let ptr = ptr.cast::<Device>();
+        if resource.is_null() {
+            return None;
+        }
 
-        // SAFETY: `ptr` was derived from `&self`.
-        unsafe { &*ptr }
+        // SAFETY: `resource` is a valid pointer to a `struct resource` as
+        // returned by `platform_get_resource`.
+        Some(unsafe { Resource::from_raw(resource) })
     }
 }
 
-impl From<&Device<device::Core>> for ARef<Device> {
-    fn from(dev: &Device<device::Core>) -> Self {
-        (&**dev).into()
+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) {
@@ -223,14 +304,34 @@ unsafe impl crate::types::AlwaysRefCounted for Device {
     }
 }
 
-impl AsRef<device::Device> for Device {
-    fn as_ref(&self) -> &device::Device {
+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::as_ref(dev) }
+        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() })
     }
 }