1 files changed, 52 insertions, 35 deletions

diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 8435f8132e38..44a2f3d2884a 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -5,16 +5,15 @@
 //! C header: [`include/linux/pci.h`](srctree/include/linux/pci.h)
 
 use crate::{
-    alloc::flags::*,
     bindings, container_of, device,
-    device_id::RawDeviceId,
+    device_id::{RawDeviceId, RawDeviceIdIndex},
     devres::Devres,
     driver,
-    error::{to_result, Result},
+    error::{from_result, to_result, Result},
     io::Io,
     io::IoRaw,
     str::CStr,
-    types::{ARef, ForeignOwnable, Opaque},
+    types::{ARef, Opaque},
     ThisModule,
 };
 use core::{
@@ -66,35 +65,34 @@ impl<T: Driver + 'static> Adapter<T> {
         // `struct pci_dev`.
         //
         // 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>>() };
 
-        // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct pci_device_id` and
+        // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct pci_device_id` and
         // does not add additional invariants, so it's safe to transmute.
         let id = unsafe { &*id.cast::<DeviceId>() };
         let info = T::ID_TABLE.info(id.index());
 
-        match T::probe(pdev, info) {
-            Ok(data) => {
-                // Let the `struct pci_dev` own a reference of the driver's private data.
-                // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a
-                // `struct pci_dev`.
-                unsafe { bindings::pci_set_drvdata(pdev.as_raw(), data.into_foreign() as _) };
-            }
-            Err(err) => return Error::to_errno(err),
-        }
+        from_result(|| {
+            let data = T::probe(pdev, info)?;
 
-        0
+            pdev.as_ref().set_drvdata(data);
+            Ok(0)
+        })
     }
 
     extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) {
         // SAFETY: The PCI bus only ever calls the remove callback with a valid pointer to a
         // `struct pci_dev`.
-        let ptr = unsafe { bindings::pci_get_drvdata(pdev) }.cast();
+        //
+        // INVARIANT: `pdev` is valid for the duration of `remove_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());
     }
 }
 
@@ -161,13 +159,14 @@ impl DeviceId {
     }
 }
 
-// SAFETY:
-// * `DeviceId` is a `#[repr(transparent)` wrapper of `pci_device_id` and does not add
-//   additional invariants, so it's safe to transmute to `RawType`.
-// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field.
+// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `pci_device_id` and does not add
+// additional invariants, so it's safe to transmute to `RawType`.
 unsafe impl RawDeviceId for DeviceId {
     type RawType = bindings::pci_device_id;
+}
 
+// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field.
+unsafe impl RawDeviceIdIndex for DeviceId {
     const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data);
 
     fn index(&self) -> usize {
@@ -241,6 +240,20 @@ pub trait Driver: Send {
     /// 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: &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 PCI device representation.
@@ -251,7 +264,8 @@ pub trait Driver: Send {
 ///
 /// # Invariants
 ///
-/// A [`Device`] instance represents a valid `struct device` created by the C portion of the kernel.
+/// A [`Device`] instance represents a valid `struct pci_dev` created by the C portion of the
+/// kernel.
 #[repr(transparent)]
 pub struct Device<Ctx: device::DeviceContext = device::Normal>(
     Opaque<bindings::pci_dev>,
@@ -398,19 +412,20 @@ impl Device {
 impl Device<device::Bound> {
     /// Mapps an entire PCI-BAR after performing a region-request on it. I/O operation bound checks
     /// can be performed on compile time for offsets (plus the requested type size) < SIZE.
-    pub fn iomap_region_sized<const SIZE: usize>(
-        &self,
+    pub fn iomap_region_sized<'a, const SIZE: usize>(
+        &'a self,
         bar: u32,
-        name: &CStr,
-    ) -> Result<Devres<Bar<SIZE>>> {
-        let bar = Bar::<SIZE>::new(self, bar, name)?;
-        let devres = Devres::new(self.as_ref(), bar, GFP_KERNEL)?;
-
-        Ok(devres)
+        name: &'a CStr,
+    ) -> impl PinInit<Devres<Bar<SIZE>>, Error> + 'a {
+        Devres::new(self.as_ref(), Bar::<SIZE>::new(self, bar, name))
     }
 
     /// Mapps an entire PCI-BAR after performing a region-request on it.
-    pub fn iomap_region(&self, bar: u32, name: &CStr) -> Result<Devres<Bar>> {
+    pub fn iomap_region<'a>(
+        &'a self,
+        bar: u32,
+        name: &'a CStr,
+    ) -> impl PinInit<Devres<Bar>, Error> + 'a {
         self.iomap_region_sized::<0>(bar, name)
     }
 }
@@ -434,6 +449,8 @@ impl Device<device::Core> {
 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) {
@@ -454,7 +471,7 @@ impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
         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) }
     }
 }