1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Abstractions for the PCI bus. 4 //! 5 //! C header: [`include/linux/pci.h`](srctree/include/linux/pci.h) 6 7 use crate::{ 8 bindings, 9 container_of, 10 device, 11 device_id::{ 12 RawDeviceId, 13 RawDeviceIdIndex, // 14 }, 15 driver, 16 error::{ 17 from_result, 18 to_result, // 19 }, 20 prelude::*, 21 str::CStr, 22 types::Opaque, 23 ThisModule, // 24 }; 25 use core::{ 26 marker::PhantomData, 27 mem::offset_of, 28 num::NonZero, 29 ptr::{ 30 addr_of_mut, 31 NonNull, // 32 }, 33 }; 34 35 mod cap; 36 mod id; 37 mod io; 38 mod irq; 39 40 pub use self::cap::{ 41 ExtCapId, 42 ExtCapability, 43 ExtSriovCapability, 44 ExtSriovRegs, 45 ExtSriovVfBar, // 46 }; 47 pub use self::id::{ 48 Class, 49 ClassMask, 50 Vendor, // 51 }; 52 pub use self::io::{ 53 Bar, 54 ConfigSpace, 55 ConfigSpaceSize, 56 DevresBar, 57 Extended, 58 Normal, // 59 }; 60 pub use self::irq::{ 61 IrqType, 62 IrqTypes, 63 IrqVector, 64 IrqVectorRegistration, // 65 }; 66 67 /// An adapter for the registration of PCI drivers. 68 pub struct Adapter<T: Driver>(T); 69 70 // SAFETY: 71 // - `bindings::pci_driver` is a C type declared as `repr(C)`. 72 // - `T::Data` is the type of the driver's device private data. 73 // - `struct pci_driver` embeds a `struct device_driver`. 74 // - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`. 75 unsafe impl<T: Driver> driver::DriverLayout for Adapter<T> { 76 type DriverType = bindings::pci_driver; 77 type DriverData<'bound> = T::Data<'bound>; 78 const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver); 79 } 80 81 // SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if 82 // a preceding call to `register` has been successful. 83 unsafe impl<T: Driver> driver::RegistrationOps for Adapter<T> { 84 unsafe fn register( 85 pdrv: &Opaque<Self::DriverType>, 86 name: &'static CStr, 87 module: &'static ThisModule, 88 ) -> Result { 89 // SAFETY: It's safe to set the fields of `struct pci_driver` on initialization. 90 unsafe { 91 (*pdrv.get()).name = name.as_char_ptr(); 92 (*pdrv.get()).probe = Some(Self::probe_callback); 93 (*pdrv.get()).remove = Some(Self::remove_callback); 94 (*pdrv.get()).id_table = T::ID_TABLE.as_ptr(); 95 } 96 97 // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`. 98 to_result(unsafe { 99 bindings::__pci_register_driver(pdrv.get(), module.as_ptr(), name.as_char_ptr()) 100 }) 101 } 102 103 unsafe fn unregister(pdrv: &Opaque<Self::DriverType>) { 104 // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`. 105 unsafe { bindings::pci_unregister_driver(pdrv.get()) } 106 } 107 } 108 109 impl<T: Driver> Adapter<T> { 110 extern "C" fn probe_callback( 111 pdev: *mut bindings::pci_dev, 112 id: *const bindings::pci_device_id, 113 ) -> c_int { 114 // SAFETY: The PCI bus only ever calls the probe callback with a valid pointer to a 115 // `struct pci_dev`. 116 // 117 // INVARIANT: `pdev` is valid for the duration of `probe_callback()`. 118 let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal<'_>>>() }; 119 120 // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct pci_device_id` and 121 // does not add additional invariants, so it's safe to transmute. 122 let id = unsafe { &*id.cast::<DeviceId>() }; 123 124 // SAFETY: `id` comes from `T::ID_TABLE` which is of type `IdArray<_, T::IdInfo>` or 125 // `pci_device_id_any` which has 0 as driver_data. It can also come from dynamic IDs, which 126 // will ensure that `driver_data` exists in `T::ID_TABLE`. 127 let info = unsafe { id.info_unchecked_opt::<T::IdInfo>() }; 128 129 from_result(|| { 130 let data = T::probe(pdev, info); 131 132 pdev.as_ref().set_drvdata(data)?; 133 Ok(0) 134 }) 135 } 136 137 extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) { 138 // SAFETY: The PCI bus only ever calls the remove callback with a valid pointer to a 139 // `struct pci_dev`. 140 // 141 // INVARIANT: `pdev` is valid for the duration of `remove_callback()`. 142 let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal<'_>>>() }; 143 144 // SAFETY: `remove_callback` is only ever called after a successful call to 145 // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called 146 // and stored a `Pin<KBox<T::Data<'_>>>`. 147 let data = unsafe { pdev.as_ref().drvdata_borrow::<T::Data<'_>>() }; 148 149 T::unbind(pdev, data); 150 } 151 } 152 153 /// Declares a kernel module that exposes a single PCI driver. 154 /// 155 /// # Examples 156 /// 157 ///```ignore 158 /// kernel::module_pci_driver! { 159 /// type: MyDriver, 160 /// name: "Module name", 161 /// authors: ["Author name"], 162 /// description: "Description", 163 /// license: "GPL v2", 164 /// } 165 ///``` 166 #[macro_export] 167 macro_rules! module_pci_driver { 168 ($($f:tt)*) => { 169 $crate::module_driver!(<T>, $crate::pci::Adapter<T>, { $($f)* }); 170 }; 171 } 172 173 /// Abstraction for the PCI device ID structure ([`struct pci_device_id`]). 174 /// 175 /// [`struct pci_device_id`]: https://docs.kernel.org/PCI/pci.html#c.pci_device_id 176 #[repr(transparent)] 177 #[derive(Clone, Copy)] 178 pub struct DeviceId(bindings::pci_device_id); 179 180 impl DeviceId { 181 const PCI_ANY_ID: u32 = !0; 182 183 /// Equivalent to C's `PCI_DEVICE` macro. 184 /// 185 /// Create a new `pci::DeviceId` from a vendor and device ID. 186 #[inline] 187 pub const fn from_id(vendor: Vendor, device: u32) -> Self { 188 Self(bindings::pci_device_id { 189 vendor: vendor.as_raw() as u32, 190 device, 191 subvendor: DeviceId::PCI_ANY_ID, 192 subdevice: DeviceId::PCI_ANY_ID, 193 class: 0, 194 class_mask: 0, 195 driver_data: 0, 196 override_only: 0, 197 }) 198 } 199 200 /// Equivalent to C's `PCI_DEVICE_CLASS` macro. 201 /// 202 /// Create a new `pci::DeviceId` from a class number and mask. 203 #[inline] 204 pub const fn from_class(class: u32, class_mask: u32) -> Self { 205 Self(bindings::pci_device_id { 206 vendor: DeviceId::PCI_ANY_ID, 207 device: DeviceId::PCI_ANY_ID, 208 subvendor: DeviceId::PCI_ANY_ID, 209 subdevice: DeviceId::PCI_ANY_ID, 210 class, 211 class_mask, 212 driver_data: 0, 213 override_only: 0, 214 }) 215 } 216 217 /// Create a new [`DeviceId`] from a class number, mask, and specific vendor. 218 /// 219 /// This is more targeted than [`DeviceId::from_class`]: in addition to matching by [`Vendor`], 220 /// it also matches the PCI [`Class`] (up to the entire 24 bits, depending on the 221 /// [`ClassMask`]). 222 #[inline] 223 pub const fn from_class_and_vendor( 224 class: Class, 225 class_mask: ClassMask, 226 vendor: Vendor, 227 ) -> Self { 228 Self(bindings::pci_device_id { 229 vendor: vendor.as_raw() as u32, 230 device: DeviceId::PCI_ANY_ID, 231 subvendor: DeviceId::PCI_ANY_ID, 232 subdevice: DeviceId::PCI_ANY_ID, 233 class: class.as_raw(), 234 class_mask: class_mask.as_raw(), 235 driver_data: 0, 236 override_only: 0, 237 }) 238 } 239 } 240 241 // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `pci_device_id` and does not add 242 // additional invariants, so it's safe to transmute to `RawType`. 243 unsafe impl RawDeviceId for DeviceId { 244 type RawType = bindings::pci_device_id; 245 } 246 247 // SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. 248 unsafe impl RawDeviceIdIndex for DeviceId { 249 const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data); 250 } 251 252 /// `IdTable` type for PCI. 253 pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; 254 255 /// Create a PCI `IdTable` with its alias for modpost. 256 #[macro_export] 257 macro_rules! pci_device_table { 258 ($($tt:tt)*) => { 259 $crate::module_device_table!("pci", $crate::pci::DeviceId, $($tt)*); 260 }; 261 } 262 263 /// The PCI driver trait. 264 /// 265 /// # Examples 266 /// 267 ///``` 268 /// # use kernel::{bindings, device::Core, pci}; 269 /// 270 /// struct MyDriver; 271 /// 272 /// kernel::pci_device_table!( 273 /// PCI_TABLE, 274 /// <MyDriver as pci::Driver>::IdInfo, 275 /// [ 276 /// ( 277 /// pci::DeviceId::from_id(pci::Vendor::REDHAT, bindings::PCI_ANY_ID as u32), 278 /// (), 279 /// ) 280 /// ] 281 /// ); 282 /// 283 /// impl pci::Driver for MyDriver { 284 /// type IdInfo = (); 285 /// type Data<'bound> = Self; 286 /// const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE; 287 /// 288 /// fn probe<'bound>( 289 /// _pdev: &'bound pci::Device<Core<'_>>, 290 /// _id_info: Option<&'bound Self::IdInfo>, 291 /// ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound { 292 /// Err(ENODEV) 293 /// } 294 /// } 295 ///``` 296 /// Drivers must implement this trait in order to get a PCI driver registered. Please refer to the 297 /// `Adapter` documentation for an example. 298 pub trait Driver { 299 /// The type holding information about each device id supported by the driver. 300 // TODO: Use `associated_type_defaults` once stabilized: 301 // 302 // ``` 303 // type IdInfo: 'static = (); 304 // ``` 305 type IdInfo: 'static; 306 307 /// The type of the driver's bus device private data. 308 type Data<'bound>: Send + 'bound; 309 310 /// The table of device ids supported by the driver. 311 const ID_TABLE: IdTable<Self::IdInfo>; 312 313 /// PCI driver probe. 314 /// 315 /// Called when a new pci device is added or discovered. Implementers should 316 /// attempt to initialize the device here. 317 fn probe<'bound>( 318 dev: &'bound Device<device::Core<'_>>, 319 id_info: Option<&'bound Self::IdInfo>, 320 ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound; 321 322 /// PCI driver unbind. 323 /// 324 /// Called when a [`Device`] is unbound from its bound [`Driver`]. Implementing this callback 325 /// is optional. 326 /// 327 /// This callback serves as a place for drivers to perform teardown operations that require a 328 /// `&Device<Core>` or `&Device<Bound>` reference. For instance, drivers may try to perform I/O 329 /// operations to gracefully tear down the device. 330 /// 331 /// Otherwise, release operations for driver resources should be performed in `Drop`. 332 fn unbind<'bound>(dev: &'bound Device<device::Core<'_>>, this: Pin<&Self::Data<'bound>>) { 333 let _ = (dev, this); 334 } 335 } 336 337 /// The PCI device representation. 338 /// 339 /// This structure represents the Rust abstraction for a C `struct pci_dev`. The implementation 340 /// abstracts the usage of an already existing C `struct pci_dev` within Rust code that we get 341 /// passed from the C side. 342 /// 343 /// # Invariants 344 /// 345 /// A [`Device`] instance represents a valid `struct pci_dev` created by the C portion of the 346 /// kernel. 347 #[repr(transparent)] 348 pub struct Device<Ctx: device::DeviceContext = device::Normal>( 349 Opaque<bindings::pci_dev>, 350 PhantomData<Ctx>, 351 ); 352 353 impl<Ctx: device::DeviceContext> Device<Ctx> { 354 #[inline] 355 fn as_raw(&self) -> *mut bindings::pci_dev { 356 self.0.get() 357 } 358 } 359 360 impl Device { 361 /// Returns the PCI vendor ID as [`Vendor`]. 362 /// 363 /// # Examples 364 /// 365 /// ``` 366 /// # use kernel::{device::Core, pci::{self, Vendor}, prelude::*}; 367 /// fn log_device_info(pdev: &pci::Device<Core<'_>>) -> Result { 368 /// // Get an instance of `Vendor`. 369 /// let vendor = pdev.vendor_id(); 370 /// dev_info!( 371 /// pdev, 372 /// "Device: Vendor={}, Device=0x{:x}\n", 373 /// vendor, 374 /// pdev.device_id() 375 /// ); 376 /// Ok(()) 377 /// } 378 /// ``` 379 #[inline] 380 pub fn vendor_id(&self) -> Vendor { 381 // SAFETY: `self.as_raw` is a valid pointer to a `struct pci_dev`. 382 let vendor_id = unsafe { (*self.as_raw()).vendor }; 383 Vendor::from_raw(vendor_id) 384 } 385 386 /// Returns the PCI device ID. 387 #[inline] 388 pub fn device_id(&self) -> u16 { 389 // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a 390 // `struct pci_dev`. 391 unsafe { (*self.as_raw()).device } 392 } 393 394 /// Returns the PCI revision ID. 395 #[inline] 396 pub fn revision_id(&self) -> u8 { 397 // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a 398 // `struct pci_dev`. 399 unsafe { (*self.as_raw()).revision } 400 } 401 402 /// Returns the PCI bus device/function. 403 #[inline] 404 pub fn dev_id(&self) -> u16 { 405 // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a 406 // `struct pci_dev`. 407 unsafe { bindings::pci_dev_id(self.as_raw()) } 408 } 409 410 /// Returns the PCI subsystem vendor ID. 411 #[inline] 412 pub fn subsystem_vendor_id(&self) -> u16 { 413 // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a 414 // `struct pci_dev`. 415 unsafe { (*self.as_raw()).subsystem_vendor } 416 } 417 418 /// Returns the PCI subsystem device ID. 419 #[inline] 420 pub fn subsystem_device_id(&self) -> u16 { 421 // SAFETY: By its type invariant `self.as_raw` is always a valid pointer to a 422 // `struct pci_dev`. 423 unsafe { (*self.as_raw()).subsystem_device } 424 } 425 426 /// Returns the start of the given PCI BAR resource. 427 pub fn resource_start(&self, bar: u32) -> Result<bindings::resource_size_t> { 428 if !Bar::index_is_valid(bar) { 429 return Err(EINVAL); 430 } 431 432 // SAFETY: 433 // - `bar` is a valid bar number, as guaranteed by the above call to `Bar::index_is_valid`, 434 // - by its type invariant `self.as_raw` is always a valid pointer to a `struct pci_dev`. 435 Ok(unsafe { bindings::pci_resource_start(self.as_raw(), bar.try_into()?) }) 436 } 437 438 /// Returns the size of the given PCI BAR resource. 439 pub fn resource_len(&self, bar: u32) -> Result<bindings::resource_size_t> { 440 if !Bar::index_is_valid(bar) { 441 return Err(EINVAL); 442 } 443 444 // SAFETY: 445 // - `bar` is a valid bar number, as guaranteed by the above call to `Bar::index_is_valid`, 446 // - by its type invariant `self.as_raw` is always a valid pointer to a `struct pci_dev`. 447 Ok(unsafe { bindings::pci_resource_len(self.as_raw(), bar.try_into()?) }) 448 } 449 450 /// Returns the PCI class as a `Class` struct. 451 #[inline] 452 pub fn pci_class(&self) -> Class { 453 // SAFETY: `self.as_raw` is a valid pointer to a `struct pci_dev`. 454 Class::from_raw(unsafe { (*self.as_raw()).class }) 455 } 456 } 457 458 impl<'a> Device<device::Core<'a>> { 459 /// Returns the total number of VFs, or [`None`] if SR-IOV is not available. 460 #[inline] 461 pub fn sriov_get_totalvfs(&self) -> Option<NonZero<u16>> { 462 // SAFETY: `self.as_raw()` is a valid pointer to a `struct pci_dev`. 463 let total_vfs = unsafe { bindings::pci_sriov_get_totalvfs(self.as_raw()) }; 464 465 // CAST: The C function returns `unsigned int`, but the value originates 466 // from TotalVFs/driver_max_VFs (which are defined as `u16`), so this cast 467 // cannot truncate. 468 NonZero::new(total_vfs as u16) 469 } 470 471 /// Enable memory resources for this device. 472 pub fn enable_device_mem(&self) -> Result { 473 // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. 474 to_result(unsafe { bindings::pci_enable_device_mem(self.as_raw()) }) 475 } 476 477 /// Enable bus-mastering for this device. 478 #[inline] 479 pub fn set_master(&self) { 480 // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. 481 unsafe { bindings::pci_set_master(self.as_raw()) }; 482 } 483 } 484 485 // SAFETY: `pci::Device` is a transparent wrapper of `struct pci_dev`. 486 // The offset is guaranteed to point to a valid device field inside `pci::Device`. 487 unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx> { 488 const OFFSET: usize = offset_of!(bindings::pci_dev, dev); 489 } 490 491 // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic 492 // argument. 493 kernel::impl_device_context_deref!(unsafe { Device }); 494 kernel::impl_device_context_into_aref!(Device); 495 496 impl<'a> crate::dma::Device<'a> for Device<device::Core<'a>> {} 497 498 // SAFETY: Instances of `Device` are always reference-counted. 499 unsafe impl crate::sync::aref::AlwaysRefCounted for Device { 500 #[inline] 501 fn inc_ref(&self) { 502 // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero. 503 unsafe { bindings::pci_dev_get(self.as_raw()) }; 504 } 505 506 #[inline] 507 unsafe fn dec_ref(obj: NonNull<Self>) { 508 // SAFETY: The safety requirements guarantee that the refcount is non-zero. 509 unsafe { bindings::pci_dev_put(obj.cast().as_ptr()) } 510 } 511 } 512 513 impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> { 514 fn as_ref(&self) -> &device::Device<Ctx> { 515 // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid 516 // `struct pci_dev`. 517 let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) }; 518 519 // SAFETY: `dev` points to a valid `struct device`. 520 unsafe { device::Device::from_raw(dev) } 521 } 522 } 523 524 impl<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &Device<Ctx> { 525 type Error = kernel::error::Error; 526 527 fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> { 528 // SAFETY: By the type invariant of `Device`, `dev.as_raw()` is a valid pointer to a 529 // `struct device`. 530 if !unsafe { bindings::dev_is_pci(dev.as_raw()) } { 531 return Err(EINVAL); 532 } 533 534 // SAFETY: We've just verified that the bus type of `dev` equals `bindings::pci_bus_type`, 535 // hence `dev` must be embedded in a valid `struct pci_dev` as guaranteed by the 536 // corresponding C code. 537 let pdev = unsafe { container_of!(dev.as_raw(), bindings::pci_dev, dev) }; 538 539 // SAFETY: `pdev` is a valid pointer to a `struct pci_dev`. 540 Ok(unsafe { &*pdev.cast() }) 541 } 542 } 543 544 // SAFETY: A `Device` is always reference-counted and can be released from any thread. 545 unsafe impl Send for Device {} 546 547 // SAFETY: `Device` can be shared among threads because all methods of `Device` 548 // (i.e. `Device<Normal>) are thread safe. 549 unsafe impl Sync for Device {} 550 551 // SAFETY: Same as `Device<Normal>` -- the underlying `struct pci_dev` is the same; 552 // `Bound` is a zero-sized type-state marker that does not affect thread safety. 553 unsafe impl Sync for Device<device::Bound> {} 554