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-rw-r--r--rust/kernel/pci.rs509
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diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
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+// SPDX-License-Identifier: GPL-2.0
+
+//! Abstractions for the PCI bus.
+//!
+//! C header: [`include/linux/pci.h`](srctree/include/linux/pci.h)
+
+use crate::{
+ bindings,
+ container_of,
+ device,
+ device_id::{
+ RawDeviceId,
+ RawDeviceIdIndex, //
+ },
+ driver,
+ error::{
+ from_result,
+ to_result, //
+ },
+ prelude::*,
+ str::CStr,
+ types::Opaque,
+ ThisModule, //
+};
+use core::{
+ marker::PhantomData,
+ mem::offset_of,
+ ptr::{
+ addr_of_mut,
+ NonNull, //
+ },
+};
+
+mod id;
+mod io;
+mod irq;
+
+pub use self::id::{
+ Class,
+ ClassMask,
+ Vendor, //
+};
+pub use self::io::Bar;
+pub use self::irq::{
+ IrqType,
+ IrqTypes,
+ IrqVector, //
+};
+
+/// An adapter for the registration of PCI 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::pci_driver;
+
+ unsafe fn register(
+ pdrv: &Opaque<Self::RegType>,
+ name: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result {
+ // SAFETY: It's safe to set the fields of `struct pci_driver` on initialization.
+ unsafe {
+ (*pdrv.get()).name = name.as_char_ptr();
+ (*pdrv.get()).probe = Some(Self::probe_callback);
+ (*pdrv.get()).remove = Some(Self::remove_callback);
+ (*pdrv.get()).id_table = T::ID_TABLE.as_ptr();
+ }
+
+ // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
+ to_result(unsafe {
+ bindings::__pci_register_driver(pdrv.get(), module.0, name.as_char_ptr())
+ })
+ }
+
+ unsafe fn unregister(pdrv: &Opaque<Self::RegType>) {
+ // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
+ unsafe { bindings::pci_unregister_driver(pdrv.get()) }
+ }
+}
+
+impl<T: Driver + 'static> Adapter<T> {
+ extern "C" fn probe_callback(
+ pdev: *mut bindings::pci_dev,
+ id: *const bindings::pci_device_id,
+ ) -> c_int {
+ // SAFETY: The PCI bus only ever calls the probe callback with a valid pointer to a
+ // `struct pci_dev`.
+ //
+ // INVARIANT: `pdev` is valid for the duration of `probe_callback()`.
+ let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal>>() };
+
+ // 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());
+
+ from_result(|| {
+ let data = T::probe(pdev, info);
+
+ 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`.
+ //
+ // 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 `Device::set_drvdata()` has been called
+ // and stored a `Pin<KBox<T>>`.
+ let data = unsafe { pdev.as_ref().drvdata_obtain::<T>() };
+
+ T::unbind(pdev, data.as_ref());
+ }
+}
+
+/// Declares a kernel module that exposes a single PCI driver.
+///
+/// # Examples
+///
+///```ignore
+/// kernel::module_pci_driver! {
+/// type: MyDriver,
+/// name: "Module name",
+/// authors: ["Author name"],
+/// description: "Description",
+/// license: "GPL v2",
+/// }
+///```
+#[macro_export]
+macro_rules! module_pci_driver {
+($($f:tt)*) => {
+ $crate::module_driver!(<T>, $crate::pci::Adapter<T>, { $($f)* });
+};
+}
+
+/// Abstraction for the PCI device ID structure ([`struct pci_device_id`]).
+///
+/// [`struct pci_device_id`]: https://docs.kernel.org/PCI/pci.html#c.pci_device_id
+#[repr(transparent)]
+#[derive(Clone, Copy)]
+pub struct DeviceId(bindings::pci_device_id);
+
+impl DeviceId {
+ const PCI_ANY_ID: u32 = !0;
+
+ /// Equivalent to C's `PCI_DEVICE` macro.
+ ///
+ /// Create a new `pci::DeviceId` from a vendor and device ID.
+ #[inline]
+ pub const fn from_id(vendor: Vendor, device: u32) -> Self {
+ Self(bindings::pci_device_id {
+ vendor: vendor.as_raw() as u32,
+ device,
+ subvendor: DeviceId::PCI_ANY_ID,
+ subdevice: DeviceId::PCI_ANY_ID,
+ class: 0,
+ class_mask: 0,
+ driver_data: 0,
+ override_only: 0,
+ })
+ }
+
+ /// Equivalent to C's `PCI_DEVICE_CLASS` macro.
+ ///
+ /// Create a new `pci::DeviceId` from a class number and mask.
+ #[inline]
+ pub const fn from_class(class: u32, class_mask: u32) -> Self {
+ Self(bindings::pci_device_id {
+ vendor: DeviceId::PCI_ANY_ID,
+ device: DeviceId::PCI_ANY_ID,
+ subvendor: DeviceId::PCI_ANY_ID,
+ subdevice: DeviceId::PCI_ANY_ID,
+ class,
+ class_mask,
+ driver_data: 0,
+ override_only: 0,
+ })
+ }
+
+ /// Create a new [`DeviceId`] from a class number, mask, and specific vendor.
+ ///
+ /// This is more targeted than [`DeviceId::from_class`]: in addition to matching by [`Vendor`],
+ /// it also matches the PCI [`Class`] (up to the entire 24 bits, depending on the
+ /// [`ClassMask`]).
+ #[inline]
+ pub const fn from_class_and_vendor(
+ class: Class,
+ class_mask: ClassMask,
+ vendor: Vendor,
+ ) -> Self {
+ Self(bindings::pci_device_id {
+ vendor: vendor.as_raw() as u32,
+ device: DeviceId::PCI_ANY_ID,
+ subvendor: DeviceId::PCI_ANY_ID,
+ subdevice: DeviceId::PCI_ANY_ID,
+ class: class.as_raw(),
+ class_mask: class_mask.as_raw(),
+ driver_data: 0,
+ override_only: 0,
+ })
+ }
+}
+
+// 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 {
+ self.0.driver_data
+ }
+}
+
+/// `IdTable` type for PCI.
+pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
+
+/// Create a PCI `IdTable` with its alias for modpost.
+#[macro_export]
+macro_rules! pci_device_table {
+ ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
+ const $table_name: $crate::device_id::IdArray<
+ $crate::pci::DeviceId,
+ $id_info_type,
+ { $table_data.len() },
+ > = $crate::device_id::IdArray::new($table_data);
+
+ $crate::module_device_table!("pci", $module_table_name, $table_name);
+ };
+}
+
+/// The PCI driver trait.
+///
+/// # Examples
+///
+///```
+/// # use kernel::{bindings, device::Core, pci};
+///
+/// struct MyDriver;
+///
+/// kernel::pci_device_table!(
+/// PCI_TABLE,
+/// MODULE_PCI_TABLE,
+/// <MyDriver as pci::Driver>::IdInfo,
+/// [
+/// (
+/// pci::DeviceId::from_id(pci::Vendor::REDHAT, bindings::PCI_ANY_ID as u32),
+/// (),
+/// )
+/// ]
+/// );
+///
+/// impl pci::Driver for MyDriver {
+/// type IdInfo = ();
+/// const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
+///
+/// fn probe(
+/// _pdev: &pci::Device<Core>,
+/// _id_info: &Self::IdInfo,
+/// ) -> impl PinInit<Self, Error> {
+/// Err(ENODEV)
+/// }
+/// }
+///```
+/// Drivers must implement this trait in order to get a PCI driver registered. Please refer to the
+/// `Adapter` documentation for an example.
+pub trait Driver: Send {
+ /// The type holding information about each device id supported by the driver.
+ // TODO: Use `associated_type_defaults` once stabilized:
+ //
+ // ```
+ // type IdInfo: 'static = ();
+ // ```
+ type IdInfo: 'static;
+
+ /// The table of device ids supported by the driver.
+ const ID_TABLE: IdTable<Self::IdInfo>;
+
+ /// PCI driver probe.
+ ///
+ /// Called when a new pci device is added or discovered. Implementers should
+ /// attempt to initialize the device here.
+ fn probe(dev: &Device<device::Core>, id_info: &Self::IdInfo) -> impl PinInit<Self, Error>;
+
+ /// PCI 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.
+///
+/// This structure represents the Rust abstraction for a C `struct pci_dev`. The implementation
+/// abstracts the usage of an already existing C `struct pci_dev` within Rust code that we get
+/// passed from the C side.
+///
+/// # Invariants
+///
+/// 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>,
+ PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> Device<Ctx> {
+ #[inline]
+ fn as_raw(&self) -> *mut bindings::pci_dev {
+ self.0.get()
+ }
+}
+
+impl Device {
+ /// Returns the PCI vendor ID as [`Vendor`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # use kernel::{device::Core, pci::{self, Vendor}, prelude::*};
+ /// fn log_device_info(pdev: &pci::Device<Core>) -> Result {
+ /// // Get an instance of `Vendor`.
+ /// let vendor = pdev.vendor_id();
+ /// dev_info!(
+ /// pdev.as_ref(),
+ /// "Device: Vendor={}, Device=0x{:x}\n",
+ /// vendor,
+ /// pdev.device_id()
+ /// );
+ /// Ok(())
+ /// }
+ /// ```
+ #[inline]
+ pub fn vendor_id(&self) -> Vendor {
+ // SAFETY: `self.as_raw` is a valid pointer to a `struct pci_dev`.
+ let vendor_id = unsafe { (*self.as_raw()).vendor };
+ Vendor::from_raw(vendor_id)
+ }
+
+ /// Returns the PCI device ID.
+ #[inline]
+ pub fn device_id(&self) -> u16 {
+ // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a
+ // `struct pci_dev`.
+ unsafe { (*self.as_raw()).device }
+ }
+
+ /// Returns the PCI revision ID.
+ #[inline]
+ pub fn revision_id(&self) -> u8 {
+ // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a
+ // `struct pci_dev`.
+ unsafe { (*self.as_raw()).revision }
+ }
+
+ /// Returns the PCI bus device/function.
+ #[inline]
+ pub fn dev_id(&self) -> u16 {
+ // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a
+ // `struct pci_dev`.
+ unsafe { bindings::pci_dev_id(self.as_raw()) }
+ }
+
+ /// Returns the PCI subsystem vendor ID.
+ #[inline]
+ pub fn subsystem_vendor_id(&self) -> u16 {
+ // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a
+ // `struct pci_dev`.
+ unsafe { (*self.as_raw()).subsystem_vendor }
+ }
+
+ /// Returns the PCI subsystem device ID.
+ #[inline]
+ pub fn subsystem_device_id(&self) -> u16 {
+ // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a
+ // `struct pci_dev`.
+ unsafe { (*self.as_raw()).subsystem_device }
+ }
+
+ /// Returns the start of the given PCI BAR resource.
+ pub fn resource_start(&self, bar: u32) -> Result<bindings::resource_size_t> {
+ if !Bar::index_is_valid(bar) {
+ return Err(EINVAL);
+ }
+
+ // SAFETY:
+ // - `bar` is a valid bar number, as guaranteed by the above call to `Bar::index_is_valid`,
+ // - by its type invariant `self.as_raw` is always a valid pointer to a `struct pci_dev`.
+ Ok(unsafe { bindings::pci_resource_start(self.as_raw(), bar.try_into()?) })
+ }
+
+ /// Returns the size of the given PCI BAR resource.
+ pub fn resource_len(&self, bar: u32) -> Result<bindings::resource_size_t> {
+ if !Bar::index_is_valid(bar) {
+ return Err(EINVAL);
+ }
+
+ // SAFETY:
+ // - `bar` is a valid bar number, as guaranteed by the above call to `Bar::index_is_valid`,
+ // - by its type invariant `self.as_raw` is always a valid pointer to a `struct pci_dev`.
+ Ok(unsafe { bindings::pci_resource_len(self.as_raw(), bar.try_into()?) })
+ }
+
+ /// Returns the PCI class as a `Class` struct.
+ #[inline]
+ pub fn pci_class(&self) -> Class {
+ // SAFETY: `self.as_raw` is a valid pointer to a `struct pci_dev`.
+ Class::from_raw(unsafe { (*self.as_raw()).class })
+ }
+}
+
+impl Device<device::Core> {
+ /// Enable memory resources for this device.
+ pub fn enable_device_mem(&self) -> Result {
+ // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`.
+ to_result(unsafe { bindings::pci_enable_device_mem(self.as_raw()) })
+ }
+
+ /// Enable bus-mastering for this device.
+ #[inline]
+ pub fn set_master(&self) {
+ // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`.
+ unsafe { bindings::pci_set_master(self.as_raw()) };
+ }
+}
+
+// SAFETY: `pci::Device` is a transparent wrapper of `struct pci_dev`.
+// The offset is guaranteed to point to a valid device field inside `pci::Device`.
+unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx> {
+ const OFFSET: usize = offset_of!(bindings::pci_dev, dev);
+}
+
+// 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::sync::aref::AlwaysRefCounted for Device {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
+ unsafe { bindings::pci_dev_get(self.as_raw()) };
+ }
+
+ unsafe fn dec_ref(obj: NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is non-zero.
+ unsafe { bindings::pci_dev_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 pci_dev`.
+ 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_pci(dev.as_raw()) } {
+ return Err(EINVAL);
+ }
+
+ // SAFETY: We've just verified that the bus type of `dev` equals `bindings::pci_bus_type`,
+ // hence `dev` must be embedded in a valid `struct pci_dev` as guaranteed by the
+ // corresponding C code.
+ let pdev = unsafe { container_of!(dev.as_raw(), bindings::pci_dev, dev) };
+
+ // SAFETY: `pdev` is a valid pointer to a `struct pci_dev`.
+ 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 {}
generated by cgit (git 2.34.1) at 2025-12-21 21:06:58 +0000