1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Abstractions for the platform bus. 4 //! 5 //! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h) 6 7 use crate::{ 8 acpi, 9 bindings, 10 container_of, 11 device::{ 12 self, 13 Bound, // 14 }, 15 driver, 16 error::{ 17 from_result, 18 to_result, // 19 }, 20 io::{ 21 mem::IoRequest, 22 Resource, // 23 }, 24 irq::{ 25 self, 26 IrqRequest, // 27 }, 28 of, 29 prelude::*, 30 types::Opaque, 31 ThisModule, // 32 }; 33 34 use core::{ 35 marker::PhantomData, 36 mem::offset_of, 37 ptr::{ 38 addr_of_mut, 39 NonNull, // 40 }, 41 }; 42 43 /// An adapter for the registration of platform drivers. 44 pub struct Adapter<T: Driver>(T); 45 46 // SAFETY: 47 // - `bindings::platform_driver` is a C type declared as `repr(C)`. 48 // - `T::Data` is the type of the driver's device private data. 49 // - `struct platform_driver` embeds a `struct device_driver`. 50 // - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`. 51 unsafe impl<T: Driver> driver::DriverLayout for Adapter<T> { 52 type DriverType = bindings::platform_driver; 53 type DriverData<'bound> = T::Data<'bound>; 54 const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver); 55 } 56 57 // SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if 58 // a preceding call to `register` has been successful. 59 unsafe impl<T: Driver> driver::RegistrationOps for Adapter<T> { 60 unsafe fn register( 61 pdrv: &Opaque<Self::DriverType>, 62 name: &'static CStr, 63 module: &'static ThisModule, 64 ) -> Result { 65 let of_table = match T::OF_ID_TABLE { 66 Some(table) => table.as_ptr(), 67 None => core::ptr::null(), 68 }; 69 70 let acpi_table = match T::ACPI_ID_TABLE { 71 Some(table) => table.as_ptr(), 72 None => core::ptr::null(), 73 }; 74 75 // SAFETY: It's safe to set the fields of `struct platform_driver` on initialization. 76 unsafe { 77 (*pdrv.get()).driver.name = name.as_char_ptr(); 78 (*pdrv.get()).probe = Some(Self::probe_callback); 79 (*pdrv.get()).remove = Some(Self::remove_callback); 80 (*pdrv.get()).driver.of_match_table = of_table; 81 (*pdrv.get()).driver.acpi_match_table = acpi_table; 82 } 83 84 // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`. 85 to_result(unsafe { 86 bindings::__platform_driver_register(pdrv.get(), module.0, name.as_char_ptr()) 87 }) 88 } 89 90 unsafe fn unregister(pdrv: &Opaque<Self::DriverType>) { 91 // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`. 92 unsafe { bindings::platform_driver_unregister(pdrv.get()) }; 93 } 94 } 95 96 impl<T: Driver> Adapter<T> { 97 extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> kernel::ffi::c_int { 98 // SAFETY: The platform bus only ever calls the probe callback with a valid pointer to a 99 // `struct platform_device`. 100 // 101 // INVARIANT: `pdev` is valid for the duration of `probe_callback()`. 102 let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal<'_>>>() }; 103 let info = <Self as driver::Adapter>::id_info(pdev.as_ref()); 104 105 from_result(|| { 106 let data = T::probe(pdev, info); 107 108 pdev.as_ref().set_drvdata(data)?; 109 Ok(0) 110 }) 111 } 112 113 extern "C" fn remove_callback(pdev: *mut bindings::platform_device) { 114 // SAFETY: The platform bus only ever calls the remove callback with a valid pointer to a 115 // `struct platform_device`. 116 // 117 // INVARIANT: `pdev` is valid for the duration of `remove_callback()`. 118 let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal<'_>>>() }; 119 120 // SAFETY: `remove_callback` is only ever called after a successful call to 121 // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called 122 // and stored a `Pin<KBox<T::Data<'_>>>`. 123 let data = unsafe { pdev.as_ref().drvdata_borrow::<T::Data<'_>>() }; 124 125 T::unbind(pdev, data); 126 } 127 } 128 129 impl<T: Driver> driver::Adapter for Adapter<T> { 130 type IdInfo = T::IdInfo; 131 132 fn of_id_table() -> Option<of::IdTable<Self::IdInfo>> { 133 T::OF_ID_TABLE 134 } 135 136 fn acpi_id_table() -> Option<acpi::IdTable<Self::IdInfo>> { 137 T::ACPI_ID_TABLE 138 } 139 } 140 141 /// Declares a kernel module that exposes a single platform driver. 142 /// 143 /// # Examples 144 /// 145 /// ```ignore 146 /// kernel::module_platform_driver! { 147 /// type: MyDriver, 148 /// name: "Module name", 149 /// authors: ["Author name"], 150 /// description: "Description", 151 /// license: "GPL v2", 152 /// } 153 /// ``` 154 #[macro_export] 155 macro_rules! module_platform_driver { 156 ($($f:tt)*) => { 157 $crate::module_driver!(<T>, $crate::platform::Adapter<T>, { $($f)* }); 158 }; 159 } 160 161 /// The platform driver trait. 162 /// 163 /// Drivers must implement this trait in order to get a platform driver registered. 164 /// 165 /// # Examples 166 /// 167 ///``` 168 /// # use kernel::{ 169 /// # acpi, 170 /// # bindings, 171 /// # device::Core, 172 /// # of, 173 /// # platform, 174 /// # }; 175 /// struct MyDriver; 176 /// 177 /// kernel::of_device_table!( 178 /// OF_TABLE, 179 /// MODULE_OF_TABLE, 180 /// <MyDriver as platform::Driver>::IdInfo, 181 /// [ 182 /// (of::DeviceId::new(c"test,device"), ()) 183 /// ] 184 /// ); 185 /// 186 /// kernel::acpi_device_table!( 187 /// ACPI_TABLE, 188 /// MODULE_ACPI_TABLE, 189 /// <MyDriver as platform::Driver>::IdInfo, 190 /// [ 191 /// (acpi::DeviceId::new(c"LNUXBEEF"), ()) 192 /// ] 193 /// ); 194 /// 195 /// impl platform::Driver for MyDriver { 196 /// type IdInfo = (); 197 /// type Data<'bound> = Self; 198 /// const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE); 199 /// const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE); 200 /// 201 /// fn probe<'bound>( 202 /// _pdev: &'bound platform::Device<Core<'_>>, 203 /// _id_info: Option<&'bound Self::IdInfo>, 204 /// ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound { 205 /// Err(ENODEV) 206 /// } 207 /// } 208 ///``` 209 pub trait Driver { 210 /// The type holding driver private data about each device id supported by the driver. 211 // TODO: Use associated_type_defaults once stabilized: 212 // 213 // ``` 214 // type IdInfo: 'static = (); 215 // ``` 216 type IdInfo: 'static; 217 218 /// The type of the driver's bus device private data. 219 type Data<'bound>: Send + 'bound; 220 221 /// The table of OF device ids supported by the driver. 222 const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = None; 223 224 /// The table of ACPI device ids supported by the driver. 225 const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = None; 226 227 /// Platform driver probe. 228 /// 229 /// Called when a new platform device is added or discovered. 230 /// Implementers should attempt to initialize the device here. 231 fn probe<'bound>( 232 dev: &'bound Device<device::Core<'_>>, 233 id_info: Option<&'bound Self::IdInfo>, 234 ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound; 235 236 /// Platform driver unbind. 237 /// 238 /// Called when a [`Device`] is unbound from its bound [`Driver`]. Implementing this callback 239 /// is optional. 240 /// 241 /// This callback serves as a place for drivers to perform teardown operations that require a 242 /// `&Device<Core>` or `&Device<Bound>` reference. For instance, drivers may try to perform I/O 243 /// operations to gracefully tear down the device. 244 /// 245 /// Otherwise, release operations for driver resources should be performed in `Drop`. 246 fn unbind<'bound>(dev: &'bound Device<device::Core<'_>>, this: Pin<&Self::Data<'bound>>) { 247 let _ = (dev, this); 248 } 249 } 250 251 /// The platform device representation. 252 /// 253 /// This structure represents the Rust abstraction for a C `struct platform_device`. The 254 /// implementation abstracts the usage of an already existing C `struct platform_device` within Rust 255 /// code that we get passed from the C side. 256 /// 257 /// # Invariants 258 /// 259 /// A [`Device`] instance represents a valid `struct platform_device` created by the C portion of 260 /// the kernel. 261 #[repr(transparent)] 262 pub struct Device<Ctx: device::DeviceContext = device::Normal>( 263 Opaque<bindings::platform_device>, 264 PhantomData<Ctx>, 265 ); 266 267 impl<Ctx: device::DeviceContext> Device<Ctx> { 268 fn as_raw(&self) -> *mut bindings::platform_device { 269 self.0.get() 270 } 271 272 /// Returns the resource at `index`, if any. 273 pub fn resource_by_index(&self, index: u32) -> Option<&Resource> { 274 // SAFETY: `self.as_raw()` returns a valid pointer to a `struct platform_device`. 275 let resource = unsafe { 276 bindings::platform_get_resource(self.as_raw(), bindings::IORESOURCE_MEM, index) 277 }; 278 279 if resource.is_null() { 280 return None; 281 } 282 283 // SAFETY: `resource` is a valid pointer to a `struct resource` as 284 // returned by `platform_get_resource`. 285 Some(unsafe { Resource::from_raw(resource) }) 286 } 287 288 /// Returns the resource with a given `name`, if any. 289 pub fn resource_by_name(&self, name: &CStr) -> Option<&Resource> { 290 // SAFETY: `self.as_raw()` returns a valid pointer to a `struct 291 // platform_device` and `name` points to a valid C string. 292 let resource = unsafe { 293 bindings::platform_get_resource_byname( 294 self.as_raw(), 295 bindings::IORESOURCE_MEM, 296 name.as_char_ptr(), 297 ) 298 }; 299 300 if resource.is_null() { 301 return None; 302 } 303 304 // SAFETY: `resource` is a valid pointer to a `struct resource` as 305 // returned by `platform_get_resource`. 306 Some(unsafe { Resource::from_raw(resource) }) 307 } 308 } 309 310 impl Device<Bound> { 311 /// Returns an `IoRequest` for the resource at `index`, if any. 312 pub fn io_request_by_index(&self, index: u32) -> Option<IoRequest<'_>> { 313 self.resource_by_index(index) 314 // SAFETY: `resource` is a valid resource for `&self` during the 315 // lifetime of the `IoRequest`. 316 .map(|resource| unsafe { IoRequest::new(self.as_ref(), resource) }) 317 } 318 319 /// Returns an `IoRequest` for the resource with a given `name`, if any. 320 pub fn io_request_by_name(&self, name: &CStr) -> Option<IoRequest<'_>> { 321 self.resource_by_name(name) 322 // SAFETY: `resource` is a valid resource for `&self` during the 323 // lifetime of the `IoRequest`. 324 .map(|resource| unsafe { IoRequest::new(self.as_ref(), resource) }) 325 } 326 } 327 328 // SAFETY: `platform::Device` is a transparent wrapper of `struct platform_device`. 329 // The offset is guaranteed to point to a valid device field inside `platform::Device`. 330 unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx> { 331 const OFFSET: usize = offset_of!(bindings::platform_device, dev); 332 } 333 334 macro_rules! define_irq_accessor_by_index { 335 ( 336 $(#[$meta:meta])* $fn_name:ident, 337 $request_fn:ident, 338 $reg_type:ident, 339 $handler_trait:ident 340 ) => { 341 $(#[$meta])* 342 pub fn $fn_name<'a, T: irq::$handler_trait + 'static>( 343 &'a self, 344 flags: irq::Flags, 345 index: u32, 346 name: &'static CStr, 347 handler: impl PinInit<T, Error> + 'a, 348 ) -> impl PinInit<irq::$reg_type<T>, Error> + 'a { 349 pin_init::pin_init_scope(move || { 350 let request = self.$request_fn(index)?; 351 352 Ok(irq::$reg_type::<T>::new( 353 request, 354 flags, 355 name, 356 handler, 357 )) 358 }) 359 } 360 }; 361 } 362 363 macro_rules! define_irq_accessor_by_name { 364 ( 365 $(#[$meta:meta])* $fn_name:ident, 366 $request_fn:ident, 367 $reg_type:ident, 368 $handler_trait:ident 369 ) => { 370 $(#[$meta])* 371 pub fn $fn_name<'a, T: irq::$handler_trait + 'static>( 372 &'a self, 373 flags: irq::Flags, 374 irq_name: &'a CStr, 375 name: &'static CStr, 376 handler: impl PinInit<T, Error> + 'a, 377 ) -> impl PinInit<irq::$reg_type<T>, Error> + 'a { 378 pin_init::pin_init_scope(move || { 379 let request = self.$request_fn(irq_name)?; 380 381 Ok(irq::$reg_type::<T>::new( 382 request, 383 flags, 384 name, 385 handler, 386 )) 387 }) 388 } 389 }; 390 } 391 392 impl Device<Bound> { 393 /// Returns an [`IrqRequest`] for the IRQ at the given index, if any. 394 pub fn irq_by_index(&self, index: u32) -> Result<IrqRequest<'_>> { 395 // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`. 396 let irq = unsafe { bindings::platform_get_irq(self.as_raw(), index) }; 397 398 if irq < 0 { 399 return Err(Error::from_errno(irq)); 400 } 401 402 // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`. 403 Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) }) 404 } 405 406 /// Returns an [`IrqRequest`] for the IRQ at the given index, but does not 407 /// print an error if the IRQ cannot be obtained. 408 pub fn optional_irq_by_index(&self, index: u32) -> Result<IrqRequest<'_>> { 409 // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`. 410 let irq = unsafe { bindings::platform_get_irq_optional(self.as_raw(), index) }; 411 412 if irq < 0 { 413 return Err(Error::from_errno(irq)); 414 } 415 416 // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`. 417 Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) }) 418 } 419 420 /// Returns an [`IrqRequest`] for the IRQ with the given name, if any. 421 pub fn irq_by_name(&self, name: &CStr) -> Result<IrqRequest<'_>> { 422 // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`. 423 let irq = unsafe { bindings::platform_get_irq_byname(self.as_raw(), name.as_char_ptr()) }; 424 425 if irq < 0 { 426 return Err(Error::from_errno(irq)); 427 } 428 429 // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`. 430 Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) }) 431 } 432 433 /// Returns an [`IrqRequest`] for the IRQ with the given name, but does not 434 /// print an error if the IRQ cannot be obtained. 435 pub fn optional_irq_by_name(&self, name: &CStr) -> Result<IrqRequest<'_>> { 436 // SAFETY: `self.as_raw` returns a valid pointer to a `struct platform_device`. 437 let irq = unsafe { 438 bindings::platform_get_irq_byname_optional(self.as_raw(), name.as_char_ptr()) 439 }; 440 441 if irq < 0 { 442 return Err(Error::from_errno(irq)); 443 } 444 445 // SAFETY: `irq` is guaranteed to be a valid IRQ number for `&self`. 446 Ok(unsafe { IrqRequest::new(self.as_ref(), irq as u32) }) 447 } 448 449 define_irq_accessor_by_index!( 450 /// Returns a [`irq::Registration`] for the IRQ at the given index. 451 request_irq_by_index, 452 irq_by_index, 453 Registration, 454 Handler 455 ); 456 define_irq_accessor_by_name!( 457 /// Returns a [`irq::Registration`] for the IRQ with the given name. 458 request_irq_by_name, 459 irq_by_name, 460 Registration, 461 Handler 462 ); 463 define_irq_accessor_by_index!( 464 /// Does the same as [`Self::request_irq_by_index`], except that it does 465 /// not print an error message if the IRQ cannot be obtained. 466 request_optional_irq_by_index, 467 optional_irq_by_index, 468 Registration, 469 Handler 470 ); 471 define_irq_accessor_by_name!( 472 /// Does the same as [`Self::request_irq_by_name`], except that it does 473 /// not print an error message if the IRQ cannot be obtained. 474 request_optional_irq_by_name, 475 optional_irq_by_name, 476 Registration, 477 Handler 478 ); 479 480 define_irq_accessor_by_index!( 481 /// Returns a [`irq::ThreadedRegistration`] for the IRQ at the given index. 482 request_threaded_irq_by_index, 483 irq_by_index, 484 ThreadedRegistration, 485 ThreadedHandler 486 ); 487 define_irq_accessor_by_name!( 488 /// Returns a [`irq::ThreadedRegistration`] for the IRQ with the given name. 489 request_threaded_irq_by_name, 490 irq_by_name, 491 ThreadedRegistration, 492 ThreadedHandler 493 ); 494 define_irq_accessor_by_index!( 495 /// Does the same as [`Self::request_threaded_irq_by_index`], except 496 /// that it does not print an error message if the IRQ cannot be 497 /// obtained. 498 request_optional_threaded_irq_by_index, 499 optional_irq_by_index, 500 ThreadedRegistration, 501 ThreadedHandler 502 ); 503 define_irq_accessor_by_name!( 504 /// Does the same as [`Self::request_threaded_irq_by_name`], except that 505 /// it does not print an error message if the IRQ cannot be obtained. 506 request_optional_threaded_irq_by_name, 507 optional_irq_by_name, 508 ThreadedRegistration, 509 ThreadedHandler 510 ); 511 } 512 513 // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic 514 // argument. 515 kernel::impl_device_context_deref!(unsafe { Device }); 516 kernel::impl_device_context_into_aref!(Device); 517 518 impl<'a> crate::dma::Device<'a> for Device<device::Core<'a>> {} 519 520 // SAFETY: Instances of `Device` are always reference-counted. 521 unsafe impl crate::sync::aref::AlwaysRefCounted for Device { 522 fn inc_ref(&self) { 523 // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero. 524 unsafe { bindings::get_device(self.as_ref().as_raw()) }; 525 } 526 527 unsafe fn dec_ref(obj: NonNull<Self>) { 528 // SAFETY: The safety requirements guarantee that the refcount is non-zero. 529 unsafe { bindings::platform_device_put(obj.cast().as_ptr()) } 530 } 531 } 532 533 impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> { 534 fn as_ref(&self) -> &device::Device<Ctx> { 535 // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid 536 // `struct platform_device`. 537 let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) }; 538 539 // SAFETY: `dev` points to a valid `struct device`. 540 unsafe { device::Device::from_raw(dev) } 541 } 542 } 543 544 impl<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &Device<Ctx> { 545 type Error = kernel::error::Error; 546 547 fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> { 548 // SAFETY: By the type invariant of `Device`, `dev.as_raw()` is a valid pointer to a 549 // `struct device`. 550 if !unsafe { bindings::dev_is_platform(dev.as_raw()) } { 551 return Err(EINVAL); 552 } 553 554 // SAFETY: We've just verified that the bus type of `dev` equals 555 // `bindings::platform_bus_type`, hence `dev` must be embedded in a valid 556 // `struct platform_device` as guaranteed by the corresponding C code. 557 let pdev = unsafe { container_of!(dev.as_raw(), bindings::platform_device, dev) }; 558 559 // SAFETY: `pdev` is a valid pointer to a `struct platform_device`. 560 Ok(unsafe { &*pdev.cast() }) 561 } 562 } 563 564 // SAFETY: A `Device` is always reference-counted and can be released from any thread. 565 unsafe impl Send for Device {} 566 567 // SAFETY: `Device` can be shared among threads because all methods of `Device` 568 // (i.e. `Device<Normal>) are thread safe. 569 unsafe impl Sync for Device {} 570 571 // SAFETY: Same as `Device<Normal>` -- the underlying `struct platform_device` is the same; 572 // `Bound` is a zero-sized type-state marker that does not affect thread safety. 573 unsafe impl Sync for Device<device::Bound> {} 574