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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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//! Abstractions for the USB bus.//!//! C header: [`include/linux/usb.h`](srctree/include/linux/usb.h)
use crate::{ bindings, device, device_id::{ RawDeviceId, RawDeviceIdIndex, // }, driver, error::{ from_result, to_result, // }, prelude::*, sync::aref::AlwaysRefCounted, types::Opaque, ThisModule, //};use core::{ marker::PhantomData, mem::{ offset_of, MaybeUninit, // }, ptr::NonNull,};
/// An adapter for the registration of USB drivers.pub struct Adapter<T: Driver>(T);
// SAFETY:// - `bindings::usb_driver` is a C type declared as `repr(C)`.// - `T::Data` is the type of the driver's device private data.// - `struct usb_driver` embeds a `struct device_driver`.// - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`.unsafe impl<T: Driver> driver::DriverLayout for Adapter<T> { type DriverType = bindings::usb_driver; type DriverData<'bound> = T::Data<'bound>; const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver);}
// SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if// a preceding call to `register` has been successful.unsafe impl<T: Driver> driver::RegistrationOps for Adapter<T> { unsafe fn register( udrv: &Opaque<Self::DriverType>, name: &'static CStr, module: &'static ThisModule, ) -> Result { // SAFETY: It's safe to set the fields of `struct usb_driver` on initialization. unsafe { (*udrv.get()).name = name.as_char_ptr(); (*udrv.get()).probe = Some(Self::probe_callback); (*udrv.get()).disconnect = Some(Self::disconnect_callback); (*udrv.get()).id_table = T::ID_TABLE.as_ptr(); }
// SAFETY: `udrv` is guaranteed to be a valid `DriverType`. to_result(unsafe { bindings::usb_register_driver(udrv.get(), module.0, name.as_char_ptr()) }) }
unsafe fn unregister(udrv: &Opaque<Self::DriverType>) { // SAFETY: `udrv` is guaranteed to be a valid `DriverType`. unsafe { bindings::usb_deregister(udrv.get()) }; }}
impl<T: Driver> Adapter<T> { extern "C" fn probe_callback( intf: *mut bindings::usb_interface, id: *const bindings::usb_device_id, ) -> kernel::ffi::c_int { // SAFETY: The USB core only ever calls the probe callback with a valid pointer to a // `struct usb_interface` and `struct usb_device_id`. // // INVARIANT: `intf` is valid for the duration of `probe_callback()`. let intf = unsafe { &*intf.cast::<Interface<device::CoreInternal<'_>>>() };
from_result(|| { // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct usb_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()); let data = T::probe(intf, id, info);
let dev: &device::Device<device::CoreInternal<'_>> = intf.as_ref(); dev.set_drvdata(data)?; Ok(0) }) }
extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) { // SAFETY: The USB core only ever calls the disconnect callback with a valid pointer to a // `struct usb_interface`. // // INVARIANT: `intf` is valid for the duration of `disconnect_callback()`. let intf = unsafe { &*intf.cast::<Interface<device::CoreInternal<'_>>>() };
let dev: &device::Device<device::CoreInternal<'_>> = intf.as_ref();
// SAFETY: `disconnect_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::Data<'_>>>`. let data = unsafe { dev.drvdata_borrow::<T::Data<'_>>() };
T::disconnect(intf, data); }}
/// Abstraction for the USB device ID structure, i.e. [`struct usb_device_id`].////// [`struct usb_device_id`]: https://docs.kernel.org/driver-api/basics.html#c.usb_device_id#[repr(transparent)]#[derive(Clone, Copy)]pub struct DeviceId(bindings::usb_device_id);
impl DeviceId { /// Equivalent to C's `USB_DEVICE` macro. pub const fn from_id(vendor: u16, product: u16) -> Self { Self(bindings::usb_device_id { match_flags: bindings::USB_DEVICE_ID_MATCH_DEVICE as u16, idVendor: vendor, idProduct: product, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_DEVICE_VER` macro. pub const fn from_device_ver(vendor: u16, product: u16, bcd_lo: u16, bcd_hi: u16) -> Self { Self(bindings::usb_device_id { match_flags: bindings::USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION as u16, idVendor: vendor, idProduct: product, bcdDevice_lo: bcd_lo, bcdDevice_hi: bcd_hi, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_DEVICE_INFO` macro. pub const fn from_device_info(class: u8, subclass: u8, protocol: u8) -> Self { Self(bindings::usb_device_id { match_flags: bindings::USB_DEVICE_ID_MATCH_DEV_INFO as u16, bDeviceClass: class, bDeviceSubClass: subclass, bDeviceProtocol: protocol, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_INTERFACE_INFO` macro. pub const fn from_interface_info(class: u8, subclass: u8, protocol: u8) -> Self { Self(bindings::usb_device_id { match_flags: bindings::USB_DEVICE_ID_MATCH_INT_INFO as u16, bInterfaceClass: class, bInterfaceSubClass: subclass, bInterfaceProtocol: protocol, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_DEVICE_INTERFACE_CLASS` macro. pub const fn from_device_interface_class(vendor: u16, product: u16, class: u8) -> Self { Self(bindings::usb_device_id { match_flags: (bindings::USB_DEVICE_ID_MATCH_DEVICE | bindings::USB_DEVICE_ID_MATCH_INT_CLASS) as u16, idVendor: vendor, idProduct: product, bInterfaceClass: class, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_DEVICE_INTERFACE_PROTOCOL` macro. pub const fn from_device_interface_protocol(vendor: u16, product: u16, protocol: u8) -> Self { Self(bindings::usb_device_id { match_flags: (bindings::USB_DEVICE_ID_MATCH_DEVICE | bindings::USB_DEVICE_ID_MATCH_INT_PROTOCOL) as u16, idVendor: vendor, idProduct: product, bInterfaceProtocol: protocol, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_DEVICE_INTERFACE_NUMBER` macro. pub const fn from_device_interface_number(vendor: u16, product: u16, number: u8) -> Self { Self(bindings::usb_device_id { match_flags: (bindings::USB_DEVICE_ID_MATCH_DEVICE | bindings::USB_DEVICE_ID_MATCH_INT_NUMBER) as u16, idVendor: vendor, idProduct: product, bInterfaceNumber: number, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }
/// Equivalent to C's `USB_DEVICE_AND_INTERFACE_INFO` macro. pub const fn from_device_and_interface_info( vendor: u16, product: u16, class: u8, subclass: u8, protocol: u8, ) -> Self { Self(bindings::usb_device_id { match_flags: (bindings::USB_DEVICE_ID_MATCH_INT_INFO | bindings::USB_DEVICE_ID_MATCH_DEVICE) as u16, idVendor: vendor, idProduct: product, bInterfaceClass: class, bInterfaceSubClass: subclass, bInterfaceProtocol: protocol, // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`. ..unsafe { MaybeUninit::zeroed().assume_init() } }) }}
// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `usb_device_id` and does not add// additional invariants, so it's safe to transmute to `RawType`.unsafe impl RawDeviceId for DeviceId { type RawType = bindings::usb_device_id;}
// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_info` field.unsafe impl RawDeviceIdIndex for DeviceId { const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::usb_device_id, driver_info);
fn index(&self) -> usize { self.0.driver_info }}
/// [`IdTable`](kernel::device_id::IdTable) type for USB.pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
/// Create a USB `IdTable` with its alias for modpost.#[macro_export]macro_rules! usb_device_table { ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => { const $table_name: $crate::device_id::IdArray< $crate::usb::DeviceId, $id_info_type, { $table_data.len() }, > = $crate::device_id::IdArray::new($table_data);
$crate::module_device_table!("usb", $module_table_name, $table_name); };}
/// The USB driver trait.////// # Examples//////```/// # use kernel::{bindings, device::Core, usb};/// use kernel::prelude::*;////// struct MyDriver;////// kernel::usb_device_table!(/// USB_TABLE,/// MODULE_USB_TABLE,/// <MyDriver as usb::Driver>::IdInfo,/// [/// (usb::DeviceId::from_id(0x1234, 0x5678), ()),/// (usb::DeviceId::from_id(0xabcd, 0xef01), ()),/// ]/// );////// impl usb::Driver for MyDriver {/// type IdInfo = ();/// type Data<'bound> = Self;/// const ID_TABLE: usb::IdTable<Self::IdInfo> = &USB_TABLE;////// fn probe<'bound>(/// _interface: &'bound usb::Interface<Core<'_>>,/// _id: &usb::DeviceId,/// _info: &'bound Self::IdInfo,/// ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {/// Err(ENODEV)/// }////// fn disconnect<'bound>(/// _interface: &'bound usb::Interface<Core<'_>>,/// _data: Pin<&Self::Data<'bound>>,/// ) {/// }/// }///```pub trait Driver { /// The type holding information about each one of the device ids supported by the driver. type IdInfo: 'static;
/// The type of the driver's bus device private data. type Data<'bound>: Send + 'bound;
/// The table of device ids supported by the driver. const ID_TABLE: IdTable<Self::IdInfo>;
/// USB driver probe. /// /// Called when a new USB interface is bound to this driver. /// Implementers should attempt to initialize the interface here. fn probe<'bound>( interface: &'bound Interface<device::Core<'_>>, id: &DeviceId, id_info: &'bound Self::IdInfo, ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound;
/// USB driver disconnect. /// /// Called when the USB interface is about to be unbound from this driver. fn disconnect<'bound>( interface: &'bound Interface<device::Core<'_>>, data: Pin<&Self::Data<'bound>>, );}
/// A USB interface.////// This structure represents the Rust abstraction for a C [`struct usb_interface`]./// The implementation abstracts the usage of a C [`struct usb_interface`] passed/// in from the C side.////// # Invariants////// An [`Interface`] instance represents a valid [`struct usb_interface`] created/// by the C portion of the kernel.////// [`struct usb_interface`]: https://www.kernel.org/doc/html/latest/driver-api/usb/usb.html#c.usb_interface#[repr(transparent)]pub struct Interface<Ctx: device::DeviceContext = device::Normal>( Opaque<bindings::usb_interface>, PhantomData<Ctx>,);
impl<Ctx: device::DeviceContext> Interface<Ctx> { fn as_raw(&self) -> *mut bindings::usb_interface { self.0.get() }}
// SAFETY: `usb::Interface` is a transparent wrapper of `struct usb_interface`.// The offset is guaranteed to point to a valid device field inside `usb::Interface`.unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Interface<Ctx> { const OFFSET: usize = offset_of!(bindings::usb_interface, dev);}
// SAFETY: `Interface` is a transparent wrapper of a type that doesn't depend on// `Interface`'s generic argument.kernel::impl_device_context_deref!(unsafe { Interface });kernel::impl_device_context_into_aref!(Interface);
impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Interface<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 usb_interface`. let dev = unsafe { &raw mut ((*self.as_raw()).dev) };
// SAFETY: `dev` points to a valid `struct device`. unsafe { device::Device::from_raw(dev) } }}
impl<Ctx: device::DeviceContext> AsRef<Device> for Interface<Ctx> { fn as_ref(&self) -> &Device { // SAFETY: `self.as_raw()` is valid by the type invariants. let usb_dev = unsafe { bindings::interface_to_usbdev(self.as_raw()) };
// SAFETY: For a valid `struct usb_interface` pointer, the above call to // `interface_to_usbdev()` guarantees to return a valid pointer to a `struct usb_device`. unsafe { &*(usb_dev.cast()) } }}
// SAFETY: Instances of `Interface` are always reference-counted.unsafe impl AlwaysRefCounted for Interface { fn inc_ref(&self) { // SAFETY: The invariants of `Interface` guarantee that `self.as_raw()` // returns a valid `struct usb_interface` pointer, for which we will // acquire a new refcount. unsafe { bindings::usb_get_intf(self.as_raw()) }; }
unsafe fn dec_ref(obj: NonNull<Self>) { // SAFETY: The safety requirements guarantee that the refcount is non-zero. unsafe { bindings::usb_put_intf(obj.cast().as_ptr()) } }}
// SAFETY: A `Interface` is always reference-counted and can be released from any thread.unsafe impl Send for Interface {}
// SAFETY: It is safe to send a &Interface to another thread because we do not// allow any mutation through a shared reference.unsafe impl Sync for Interface {}
/// A USB device.////// This structure represents the Rust abstraction for a C [`struct usb_device`]./// The implementation abstracts the usage of a C [`struct usb_device`] passed in/// from the C side.////// # Invariants////// A [`Device`] instance represents a valid [`struct usb_device`] created by the C portion of the/// kernel.////// [`struct usb_device`]: https://www.kernel.org/doc/html/latest/driver-api/usb/usb.html#c.usb_device#[repr(transparent)]struct Device<Ctx: device::DeviceContext = device::Normal>( Opaque<bindings::usb_device>, PhantomData<Ctx>,);
impl<Ctx: device::DeviceContext> Device<Ctx> { fn as_raw(&self) -> *mut bindings::usb_device { self.0.get() }}
// 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);
// SAFETY: Instances of `Device` are always reference-counted.unsafe impl AlwaysRefCounted for Device { fn inc_ref(&self) { // SAFETY: The invariants of `Device` guarantee that `self.as_raw()` // returns a valid `struct usb_device` pointer, for which we will // acquire a new refcount. unsafe { bindings::usb_get_dev(self.as_raw()) }; }
unsafe fn dec_ref(obj: NonNull<Self>) { // SAFETY: The safety requirements guarantee that the refcount is non-zero. unsafe { bindings::usb_put_dev(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 usb_device`. let dev = unsafe { &raw mut ((*self.as_raw()).dev) };
// SAFETY: `dev` points to a valid `struct device`. unsafe { device::Device::from_raw(dev) } }}
// SAFETY: A `Device` is always reference-counted and can be released from any thread.unsafe impl Send for Device {}
// SAFETY: It is safe to send a &Device to another thread because we do not// allow any mutation through a shared reference.unsafe impl Sync for Device {}
// SAFETY: Same as `Device<Normal>` -- the underlying `struct usb_device` is the same;// `Bound` is a zero-sized type-state marker that does not affect thread safety.unsafe impl Sync for Device<device::Bound> {}
/// Declares a kernel module that exposes a single USB driver.////// # Examples////// ```ignore/// module_usb_driver! {/// type: MyDriver,/// name: "Module name",/// author: ["Author name"],/// description: "Description",/// license: "GPL v2",/// }/// ```#[macro_export]macro_rules! module_usb_driver { ($($f:tt)*) => { $crate::module_driver!(<T>, $crate::usb::Adapter<T>, { $($f)* }); }}