| Message ID | 20241022213221.2383-12-dakr@kernel.org (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | Device / Driver PCI / Platform Rust abstractions | expand |
Hi Danilo, On Tue, Oct 22, 2024 at 11:31:48PM +0200, Danilo Krummrich wrote: [...] > +/// The PCI device representation. > +/// > +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI > +/// device, hence, also increments the base device' reference count. > +#[derive(Clone)] > +pub struct Device(ARef<device::Device>); > + Similar to https://lore.kernel.org/rust-for-linux/ZgG7TlybSa00cuoy@boqun-archlinux/ Could you also avoid wrapping a point to a PCI device? Instead, wrap the object type: #[repr(transparent)] pub struct Device(Opaque<bindings::pci_dev>); impl AlwaysRefCounted for Device { <put_device() and get_device() on ->dev> } Regards, Boqun > +impl Device { > + /// Create a PCI Device instance from an existing `device::Device`. > + /// > + /// # Safety > + /// > + /// `dev` must be an `ARef<device::Device>` whose underlying `bindings::device` is a member of > + /// a `bindings::pci_dev`. > + pub unsafe fn from_dev(dev: ARef<device::Device>) -> Self { > + Self(dev) > + } > + > + fn as_raw(&self) -> *mut bindings::pci_dev { > + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` > + // embedded in `struct pci_dev`. > + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } > + } > + > + /// 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`. > + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; > + if ret != 0 { > + Err(Error::from_errno(ret)) > + } else { > + Ok(()) > + } > + } > + > + /// Enable bus-mastering for this device. > + 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()) }; > + } > +} > + > +impl AsRef<device::Device> for Device { > + fn as_ref(&self) -> &device::Device { > + &self.0 > + } > +} > -- > 2.46.2 > >
On Sun, Oct 27, 2024 at 03:42:41PM -0700, Boqun Feng wrote: > Hi Danilo, > > On Tue, Oct 22, 2024 at 11:31:48PM +0200, Danilo Krummrich wrote: > [...] > > +/// The PCI device representation. > > +/// > > +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI > > +/// device, hence, also increments the base device' reference count. > > +#[derive(Clone)] > > +pub struct Device(ARef<device::Device>); > > + > > Similar to https://lore.kernel.org/rust-for-linux/ZgG7TlybSa00cuoy@boqun-archlinux/ > > Could you also avoid wrapping a point to a PCI device? Instead, wrap the > object type: > > #[repr(transparent)] > pub struct Device(Opaque<bindings::pci_dev>); > > impl AlwaysRefCounted for Device { > <put_device() and get_device() on ->dev> > } Yeah, the idea was to avoid the duplicate implementation of `AlwaysRefCounted`, but I agree it's a bit messy. Will change it. > > Regards, > Boqun > > > +impl Device { > > + /// Create a PCI Device instance from an existing `device::Device`. > > + /// > > + /// # Safety > > + /// > > + /// `dev` must be an `ARef<device::Device>` whose underlying `bindings::device` is a member of > > + /// a `bindings::pci_dev`. > > + pub unsafe fn from_dev(dev: ARef<device::Device>) -> Self { > > + Self(dev) > > + } > > + > > + fn as_raw(&self) -> *mut bindings::pci_dev { > > + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` > > + // embedded in `struct pci_dev`. > > + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } > > + } > > + > > + /// 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`. > > + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; > > + if ret != 0 { > > + Err(Error::from_errno(ret)) > > + } else { > > + Ok(()) > > + } > > + } > > + > > + /// Enable bus-mastering for this device. > > + 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()) }; > > + } > > +} > > + > > +impl AsRef<device::Device> for Device { > > + fn as_ref(&self) -> &device::Device { > > + &self.0 > > + } > > +} > > -- > > 2.46.2 > > > > >
Hi, On 22.10.24 11:31 PM, Danilo Krummrich wrote: > Implement the basic PCI abstractions required to write a basic PCI > driver. This includes the following data structures: > > The `pci::Driver` trait represents the interface to the driver and > provides `pci::Driver::probe` for the driver to implement. > > The `pci::Device` abstraction represents a `struct pci_dev` and provides > abstractions for common functions, such as `pci::Device::set_master`. > > In order to provide the PCI specific parts to a generic > `driver::Registration` the `driver::RegistrationOps` trait is implemented > by `pci::Adapter`. > > `pci::DeviceId` implements PCI device IDs based on the generic > `device_id::RawDevceId` abstraction. > > Co-developed-by: FUJITA Tomonori <fujita.tomonori@gmail.com> > Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> > Signed-off-by: Danilo Krummrich <dakr@kernel.org> > --- > MAINTAINERS | 1 + > rust/bindings/bindings_helper.h | 1 + > rust/helpers/helpers.c | 1 + > rust/helpers/pci.c | 18 ++ > rust/kernel/lib.rs | 2 + > rust/kernel/pci.rs | 284 ++++++++++++++++++++++++++++++++ > 6 files changed, 307 insertions(+) > create mode 100644 rust/helpers/pci.c > create mode 100644 rust/kernel/pci.rs > > diff --git a/MAINTAINERS b/MAINTAINERS > index 97914d0752fb..2d00d3845b4a 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -17939,6 +17939,7 @@ F: include/asm-generic/pci* > F: include/linux/of_pci.h > F: include/linux/pci* > F: include/uapi/linux/pci* > +F: rust/kernel/pci.rs > > PCIE DRIVER FOR AMAZON ANNAPURNA LABS > M: Jonathan Chocron <jonnyc@amazon.com> > diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h > index a80783fcbe04..cd4edd6496ae 100644 > --- a/rust/bindings/bindings_helper.h > +++ b/rust/bindings/bindings_helper.h > @@ -15,6 +15,7 @@ > #include <linux/firmware.h> > #include <linux/jiffies.h> > #include <linux/mdio.h> > +#include <linux/pci.h> > #include <linux/phy.h> > #include <linux/refcount.h> > #include <linux/sched.h> > diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c > index 3acb2b9e52ec..8bc6e9735589 100644 > --- a/rust/helpers/helpers.c > +++ b/rust/helpers/helpers.c > @@ -17,6 +17,7 @@ > #include "kunit.c" > #include "mutex.c" > #include "page.c" > +#include "pci.c" > #include "rbtree.c" > #include "rcu.c" > #include "refcount.c" > diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c > new file mode 100644 > index 000000000000..7c4f3ba49486 > --- /dev/null > +++ b/rust/helpers/pci.c > @@ -0,0 +1,18 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include <linux/pci.h> > + > +void rust_helper_pci_set_drvdata(struct pci_dev *pdev, void *data) > +{ > + pci_set_drvdata(pdev, data); > +} > + > +void *rust_helper_pci_get_drvdata(struct pci_dev *pdev) > +{ > + return pci_get_drvdata(pdev); > +} > + > +u64 rust_helper_pci_resource_len(struct pci_dev *pdev, int bar) > +{ > + return pci_resource_len(pdev, bar); > +} This should return resource_size_t to build on 32 bit architectures. Error when building with my 32 bit arm patch: error[E0308]: mismatched types --> rust/kernel/pci.rs:398:21 | 398 | Ok(unsafe { bindings::pci_resource_len(self.as_raw(), bar.try_into()?) }) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `u32`, found `u64` | help: you can convert a `u64` to a `u32` and panic if the converted value doesn't fit | 398 | Ok(unsafe { bindings::pci_resource_len(self.as_raw(), bar.try_into()?).try_into().unwrap() }) | ++++++++++++++++++++ error: aborting due to 1 previous error > diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs > index 5cb892419453..3ec690eb6d43 100644 > --- a/rust/kernel/lib.rs > +++ b/rust/kernel/lib.rs > @@ -73,6 +73,8 @@ > pub use bindings; > pub mod io; > pub use macros; > +#[cfg(all(CONFIG_PCI, CONFIG_PCI_MSI))] > +pub mod pci; > pub use uapi; > > #[doc(hidden)] > diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs > new file mode 100644 > index 000000000000..ccc9a5f322e4 > --- /dev/null > +++ b/rust/kernel/pci.rs > @@ -0,0 +1,284 @@ > +// 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, > + driver, > + error::{to_result, Result}, > + str::CStr, > + types::{ARef, ForeignOwnable}, > + ThisModule, > +}; > +use core::ops::Deref; > +use kernel::prelude::*; > + > +/// An adapter for the registration of PCI drivers. > +pub struct Adapter<T: Driver>(T); > + > +impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> { > + type RegType = bindings::pci_driver; > + > + fn register( > + pdrv: &mut Self::RegType, > + name: &'static CStr, > + module: &'static ThisModule, > + ) -> Result { > + pdrv.name = name.as_char_ptr(); > + pdrv.probe = Some(Self::probe_callback); > + pdrv.remove = Some(Self::remove_callback); > + pdrv.id_table = T::ID_TABLE.as_ptr(); > + > + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. > + to_result(unsafe { > + bindings::__pci_register_driver(pdrv as _, module.0, name.as_char_ptr()) > + }) > + } > + > + fn unregister(pdrv: &mut Self::RegType) { > + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. > + unsafe { bindings::pci_unregister_driver(pdrv) } > + } > +} > + > +impl<T: Driver + 'static> Adapter<T> { > + extern "C" fn probe_callback( > + pdev: *mut bindings::pci_dev, > + id: *const bindings::pci_device_id, > + ) -> core::ffi::c_int { > + // SAFETY: The PCI bus only ever calls the probe callback with a valid pointer to a > + // `struct pci_dev`. > + let dev = unsafe { device::Device::from_raw(&mut (*pdev).dev) }; > + // SAFETY: `dev` is guaranteed to be embedded in a valid `struct pci_dev` by the call > + // above. > + let mut pdev = unsafe { Device::from_dev(dev) }; > + > + // 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(&mut pdev, id, 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), > + } > + > + 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) }; > + > + // 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) }; > + } > +} > + > +/// Declares a kernel module that exposes a single PCI driver. > +/// > +/// # Example > +/// > +///```ignore > +/// kernel::module_pci_driver! { > +/// type: MyDriver, > +/// name: "Module name", > +/// author: "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 bindings::pci_device_id. > +#[repr(transparent)] > +#[derive(Clone, Copy)] > +pub struct DeviceId(bindings::pci_device_id); > + > +impl DeviceId { > + const PCI_ANY_ID: u32 = !0; > + > + /// PCI_DEVICE macro. > + pub const fn new(vendor: u32, device: u32) -> Self { > + Self(bindings::pci_device_id { > + vendor, > + device, > + subvendor: DeviceId::PCI_ANY_ID, > + subdevice: DeviceId::PCI_ANY_ID, > + class: 0, > + class_mask: 0, > + driver_data: 0, > + override_only: 0, > + }) > + } > + > + /// PCI_DEVICE_CLASS macro. > + pub const fn with_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, > + }) > + } > +} > + > +// Allow drivers R/O access to the fields of `pci_device_id`; should we prefer accessor functions > +// to void exposing C structure fields? > +impl Deref for DeviceId { > + type Target = bindings::pci_device_id; > + > + fn deref(&self) -> &Self::Target { > + &self.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`. > +// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. > +unsafe impl RawDeviceId for DeviceId { > + type RawType = bindings::pci_device_id; > + > + const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data); > + > + fn index(&self) -> usize { > + self.driver_data as _ > + } > +} > + > +/// 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. > +/// > +/// # Example > +/// > +///``` > +/// # use kernel::{bindings, pci}; > +/// > +/// struct MyDriver; > +/// > +/// kernel::pci_device_table!( > +/// PCI_TABLE, > +/// MODULE_PCI_TABLE, > +/// <MyDriver as pci::Driver>::IdInfo, > +/// [ > +/// (pci::DeviceId::new(bindings::PCI_VENDOR_ID_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: &mut pci::Device, > +/// _id: &pci::DeviceId, > +/// _id_info: &Self::IdInfo, > +/// ) -> Result<Pin<KBox<Self>>> { > +/// 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 { > + /// 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 platform device is added or discovered. > + /// Implementers should attempt to initialize the device here. > + fn probe(dev: &mut Device, id: &DeviceId, id_info: &Self::IdInfo) -> Result<Pin<KBox<Self>>>; > +} > + > +/// The PCI device representation. > +/// > +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI > +/// device, hence, also increments the base device' reference count. > +#[derive(Clone)] > +pub struct Device(ARef<device::Device>); > + > +impl Device { > + /// Create a PCI Device instance from an existing `device::Device`. > + /// > + /// # Safety > + /// > + /// `dev` must be an `ARef<device::Device>` whose underlying `bindings::device` is a member of > + /// a `bindings::pci_dev`. > + pub unsafe fn from_dev(dev: ARef<device::Device>) -> Self { > + Self(dev) > + } > + > + fn as_raw(&self) -> *mut bindings::pci_dev { > + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` > + // embedded in `struct pci_dev`. > + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } > + } > + > + /// 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`. > + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; > + if ret != 0 { > + Err(Error::from_errno(ret)) > + } else { > + Ok(()) > + } > + } > + > + /// Enable bus-mastering for this device. > + 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()) }; > + } > +} > + > +impl AsRef<device::Device> for Device { > + fn as_ref(&self) -> &device::Device { > + &self.0 > + } > +} Cheers Christian
diff --git a/MAINTAINERS b/MAINTAINERS index 97914d0752fb..2d00d3845b4a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17939,6 +17939,7 @@ F: include/asm-generic/pci* F: include/linux/of_pci.h F: include/linux/pci* F: include/uapi/linux/pci* +F: rust/kernel/pci.rs PCIE DRIVER FOR AMAZON ANNAPURNA LABS M: Jonathan Chocron <jonnyc@amazon.com> diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index a80783fcbe04..cd4edd6496ae 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -15,6 +15,7 @@ #include <linux/firmware.h> #include <linux/jiffies.h> #include <linux/mdio.h> +#include <linux/pci.h> #include <linux/phy.h> #include <linux/refcount.h> #include <linux/sched.h> diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 3acb2b9e52ec..8bc6e9735589 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -17,6 +17,7 @@ #include "kunit.c" #include "mutex.c" #include "page.c" +#include "pci.c" #include "rbtree.c" #include "rcu.c" #include "refcount.c" diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c new file mode 100644 index 000000000000..7c4f3ba49486 --- /dev/null +++ b/rust/helpers/pci.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/pci.h> + +void rust_helper_pci_set_drvdata(struct pci_dev *pdev, void *data) +{ + pci_set_drvdata(pdev, data); +} + +void *rust_helper_pci_get_drvdata(struct pci_dev *pdev) +{ + return pci_get_drvdata(pdev); +} + +u64 rust_helper_pci_resource_len(struct pci_dev *pdev, int bar) +{ + return pci_resource_len(pdev, bar); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 5cb892419453..3ec690eb6d43 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -73,6 +73,8 @@ pub use bindings; pub mod io; pub use macros; +#[cfg(all(CONFIG_PCI, CONFIG_PCI_MSI))] +pub mod pci; pub use uapi; #[doc(hidden)] diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs new file mode 100644 index 000000000000..ccc9a5f322e4 --- /dev/null +++ b/rust/kernel/pci.rs @@ -0,0 +1,284 @@ +// 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, + driver, + error::{to_result, Result}, + str::CStr, + types::{ARef, ForeignOwnable}, + ThisModule, +}; +use core::ops::Deref; +use kernel::prelude::*; + +/// An adapter for the registration of PCI drivers. +pub struct Adapter<T: Driver>(T); + +impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> { + type RegType = bindings::pci_driver; + + fn register( + pdrv: &mut Self::RegType, + name: &'static CStr, + module: &'static ThisModule, + ) -> Result { + pdrv.name = name.as_char_ptr(); + pdrv.probe = Some(Self::probe_callback); + pdrv.remove = Some(Self::remove_callback); + pdrv.id_table = T::ID_TABLE.as_ptr(); + + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + to_result(unsafe { + bindings::__pci_register_driver(pdrv as _, module.0, name.as_char_ptr()) + }) + } + + fn unregister(pdrv: &mut Self::RegType) { + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + unsafe { bindings::pci_unregister_driver(pdrv) } + } +} + +impl<T: Driver + 'static> Adapter<T> { + extern "C" fn probe_callback( + pdev: *mut bindings::pci_dev, + id: *const bindings::pci_device_id, + ) -> core::ffi::c_int { + // SAFETY: The PCI bus only ever calls the probe callback with a valid pointer to a + // `struct pci_dev`. + let dev = unsafe { device::Device::from_raw(&mut (*pdev).dev) }; + // SAFETY: `dev` is guaranteed to be embedded in a valid `struct pci_dev` by the call + // above. + let mut pdev = unsafe { Device::from_dev(dev) }; + + // 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(&mut pdev, id, 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), + } + + 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) }; + + // 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) }; + } +} + +/// Declares a kernel module that exposes a single PCI driver. +/// +/// # Example +/// +///```ignore +/// kernel::module_pci_driver! { +/// type: MyDriver, +/// name: "Module name", +/// author: "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 bindings::pci_device_id. +#[repr(transparent)] +#[derive(Clone, Copy)] +pub struct DeviceId(bindings::pci_device_id); + +impl DeviceId { + const PCI_ANY_ID: u32 = !0; + + /// PCI_DEVICE macro. + pub const fn new(vendor: u32, device: u32) -> Self { + Self(bindings::pci_device_id { + vendor, + device, + subvendor: DeviceId::PCI_ANY_ID, + subdevice: DeviceId::PCI_ANY_ID, + class: 0, + class_mask: 0, + driver_data: 0, + override_only: 0, + }) + } + + /// PCI_DEVICE_CLASS macro. + pub const fn with_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, + }) + } +} + +// Allow drivers R/O access to the fields of `pci_device_id`; should we prefer accessor functions +// to void exposing C structure fields? +impl Deref for DeviceId { + type Target = bindings::pci_device_id; + + fn deref(&self) -> &Self::Target { + &self.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`. +// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceId for DeviceId { + type RawType = bindings::pci_device_id; + + const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data); + + fn index(&self) -> usize { + self.driver_data as _ + } +} + +/// 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. +/// +/// # Example +/// +///``` +/// # use kernel::{bindings, pci}; +/// +/// struct MyDriver; +/// +/// kernel::pci_device_table!( +/// PCI_TABLE, +/// MODULE_PCI_TABLE, +/// <MyDriver as pci::Driver>::IdInfo, +/// [ +/// (pci::DeviceId::new(bindings::PCI_VENDOR_ID_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: &mut pci::Device, +/// _id: &pci::DeviceId, +/// _id_info: &Self::IdInfo, +/// ) -> Result<Pin<KBox<Self>>> { +/// 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 { + /// 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 platform device is added or discovered. + /// Implementers should attempt to initialize the device here. + fn probe(dev: &mut Device, id: &DeviceId, id_info: &Self::IdInfo) -> Result<Pin<KBox<Self>>>; +} + +/// The PCI device representation. +/// +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI +/// device, hence, also increments the base device' reference count. +#[derive(Clone)] +pub struct Device(ARef<device::Device>); + +impl Device { + /// Create a PCI Device instance from an existing `device::Device`. + /// + /// # Safety + /// + /// `dev` must be an `ARef<device::Device>` whose underlying `bindings::device` is a member of + /// a `bindings::pci_dev`. + pub unsafe fn from_dev(dev: ARef<device::Device>) -> Self { + Self(dev) + } + + fn as_raw(&self) -> *mut bindings::pci_dev { + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` + // embedded in `struct pci_dev`. + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } + } + + /// 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`. + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; + if ret != 0 { + Err(Error::from_errno(ret)) + } else { + Ok(()) + } + } + + /// Enable bus-mastering for this device. + 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()) }; + } +} + +impl AsRef<device::Device> for Device { + fn as_ref(&self) -> &device::Device { + &self.0 + } +}