xref: /linux/rust/kernel/net/phy.rs (revision 55f1b540d893da740a81200450014c45a8103f54)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 // Copyright (C) 2023 FUJITA Tomonori <fujita.tomonori@gmail.com>
4 
5 //! Network PHY device.
6 //!
7 //! C headers: [`include/linux/phy.h`](srctree/include/linux/phy.h).
8 
9 use crate::{error::*, prelude::*, types::Opaque};
10 use core::{marker::PhantomData, ptr::addr_of_mut};
11 
12 pub mod reg;
13 
14 /// PHY state machine states.
15 ///
16 /// Corresponds to the kernel's [`enum phy_state`].
17 ///
18 /// Some of PHY drivers access to the state of PHY's software state machine.
19 ///
20 /// [`enum phy_state`]: srctree/include/linux/phy.h
21 #[derive(PartialEq, Eq)]
22 pub enum DeviceState {
23     /// PHY device and driver are not ready for anything.
24     Down,
25     /// PHY is ready to send and receive packets.
26     Ready,
27     /// PHY is up, but no polling or interrupts are done.
28     Halted,
29     /// PHY is up, but is in an error state.
30     Error,
31     /// PHY and attached device are ready to do work.
32     Up,
33     /// PHY is currently running.
34     Running,
35     /// PHY is up, but not currently plugged in.
36     NoLink,
37     /// PHY is performing a cable test.
38     CableTest,
39 }
40 
41 /// A mode of Ethernet communication.
42 ///
43 /// PHY drivers get duplex information from hardware and update the current state.
44 pub enum DuplexMode {
45     /// PHY is in full-duplex mode.
46     Full,
47     /// PHY is in half-duplex mode.
48     Half,
49     /// PHY is in unknown duplex mode.
50     Unknown,
51 }
52 
53 /// An instance of a PHY device.
54 ///
55 /// Wraps the kernel's [`struct phy_device`].
56 ///
57 /// A [`Device`] instance is created when a callback in [`Driver`] is executed. A PHY driver
58 /// executes [`Driver`]'s methods during the callback.
59 ///
60 /// # Invariants
61 ///
62 /// - Referencing a `phy_device` using this struct asserts that you are in
63 ///   a context where all methods defined on this struct are safe to call.
64 /// - This struct always has a valid `self.0.mdio.dev`.
65 ///
66 /// [`struct phy_device`]: srctree/include/linux/phy.h
67 // During the calls to most functions in [`Driver`], the C side (`PHYLIB`) holds a lock that is
68 // unique for every instance of [`Device`]. `PHYLIB` uses a different serialization technique for
69 // [`Driver::resume`] and [`Driver::suspend`]: `PHYLIB` updates `phy_device`'s state with
70 // the lock held, thus guaranteeing that [`Driver::resume`] has exclusive access to the instance.
71 // [`Driver::resume`] and [`Driver::suspend`] also are called where only one thread can access
72 // to the instance.
73 #[repr(transparent)]
74 pub struct Device(Opaque<bindings::phy_device>);
75 
76 impl Device {
77     /// Creates a new [`Device`] instance from a raw pointer.
78     ///
79     /// # Safety
80     ///
81     /// For the duration of `'a`,
82     /// - the pointer must point at a valid `phy_device`, and the caller
83     ///   must be in a context where all methods defined on this struct
84     ///   are safe to call.
85     /// - `(*ptr).mdio.dev` must be a valid.
86     unsafe fn from_raw<'a>(ptr: *mut bindings::phy_device) -> &'a mut Self {
87         // CAST: `Self` is a `repr(transparent)` wrapper around `bindings::phy_device`.
88         let ptr = ptr.cast::<Self>();
89         // SAFETY: by the function requirements the pointer is valid and we have unique access for
90         // the duration of `'a`.
91         unsafe { &mut *ptr }
92     }
93 
94     /// Gets the id of the PHY.
95     pub fn phy_id(&self) -> u32 {
96         let phydev = self.0.get();
97         // SAFETY: The struct invariant ensures that we may access
98         // this field without additional synchronization.
99         unsafe { (*phydev).phy_id }
100     }
101 
102     /// Gets the state of PHY state machine states.
103     pub fn state(&self) -> DeviceState {
104         let phydev = self.0.get();
105         // SAFETY: The struct invariant ensures that we may access
106         // this field without additional synchronization.
107         let state = unsafe { (*phydev).state };
108         // TODO: this conversion code will be replaced with automatically generated code by bindgen
109         // when it becomes possible.
110         match state {
111             bindings::phy_state_PHY_DOWN => DeviceState::Down,
112             bindings::phy_state_PHY_READY => DeviceState::Ready,
113             bindings::phy_state_PHY_HALTED => DeviceState::Halted,
114             bindings::phy_state_PHY_ERROR => DeviceState::Error,
115             bindings::phy_state_PHY_UP => DeviceState::Up,
116             bindings::phy_state_PHY_RUNNING => DeviceState::Running,
117             bindings::phy_state_PHY_NOLINK => DeviceState::NoLink,
118             bindings::phy_state_PHY_CABLETEST => DeviceState::CableTest,
119             _ => DeviceState::Error,
120         }
121     }
122 
123     /// Gets the current link state.
124     ///
125     /// It returns true if the link is up.
126     pub fn is_link_up(&self) -> bool {
127         const LINK_IS_UP: u64 = 1;
128         // TODO: the code to access to the bit field will be replaced with automatically
129         // generated code by bindgen when it becomes possible.
130         // SAFETY: The struct invariant ensures that we may access
131         // this field without additional synchronization.
132         let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
133         bit_field.get(14, 1) == LINK_IS_UP
134     }
135 
136     /// Gets the current auto-negotiation configuration.
137     ///
138     /// It returns true if auto-negotiation is enabled.
139     pub fn is_autoneg_enabled(&self) -> bool {
140         // TODO: the code to access to the bit field will be replaced with automatically
141         // generated code by bindgen when it becomes possible.
142         // SAFETY: The struct invariant ensures that we may access
143         // this field without additional synchronization.
144         let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
145         bit_field.get(13, 1) == bindings::AUTONEG_ENABLE as u64
146     }
147 
148     /// Gets the current auto-negotiation state.
149     ///
150     /// It returns true if auto-negotiation is completed.
151     pub fn is_autoneg_completed(&self) -> bool {
152         const AUTONEG_COMPLETED: u64 = 1;
153         // TODO: the code to access to the bit field will be replaced with automatically
154         // generated code by bindgen when it becomes possible.
155         // SAFETY: The struct invariant ensures that we may access
156         // this field without additional synchronization.
157         let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
158         bit_field.get(15, 1) == AUTONEG_COMPLETED
159     }
160 
161     /// Sets the speed of the PHY.
162     pub fn set_speed(&mut self, speed: u32) {
163         let phydev = self.0.get();
164         // SAFETY: The struct invariant ensures that we may access
165         // this field without additional synchronization.
166         unsafe { (*phydev).speed = speed as i32 };
167     }
168 
169     /// Sets duplex mode.
170     pub fn set_duplex(&mut self, mode: DuplexMode) {
171         let phydev = self.0.get();
172         let v = match mode {
173             DuplexMode::Full => bindings::DUPLEX_FULL as i32,
174             DuplexMode::Half => bindings::DUPLEX_HALF as i32,
175             DuplexMode::Unknown => bindings::DUPLEX_UNKNOWN as i32,
176         };
177         // SAFETY: The struct invariant ensures that we may access
178         // this field without additional synchronization.
179         unsafe { (*phydev).duplex = v };
180     }
181 
182     /// Reads a PHY register.
183     // This function reads a hardware register and updates the stats so takes `&mut self`.
184     pub fn read<R: reg::Register>(&mut self, reg: R) -> Result<u16> {
185         reg.read(self)
186     }
187 
188     /// Writes a PHY register.
189     pub fn write<R: reg::Register>(&mut self, reg: R, val: u16) -> Result {
190         reg.write(self, val)
191     }
192 
193     /// Reads a paged register.
194     pub fn read_paged(&mut self, page: u16, regnum: u16) -> Result<u16> {
195         let phydev = self.0.get();
196         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
197         // So it's just an FFI call.
198         let ret = unsafe { bindings::phy_read_paged(phydev, page.into(), regnum.into()) };
199         if ret < 0 {
200             Err(Error::from_errno(ret))
201         } else {
202             Ok(ret as u16)
203         }
204     }
205 
206     /// Resolves the advertisements into PHY settings.
207     pub fn resolve_aneg_linkmode(&mut self) {
208         let phydev = self.0.get();
209         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
210         // So it's just an FFI call.
211         unsafe { bindings::phy_resolve_aneg_linkmode(phydev) };
212     }
213 
214     /// Executes software reset the PHY via `BMCR_RESET` bit.
215     pub fn genphy_soft_reset(&mut self) -> Result {
216         let phydev = self.0.get();
217         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
218         // So it's just an FFI call.
219         to_result(unsafe { bindings::genphy_soft_reset(phydev) })
220     }
221 
222     /// Initializes the PHY.
223     pub fn init_hw(&mut self) -> Result {
224         let phydev = self.0.get();
225         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
226         // So it's just an FFI call.
227         to_result(unsafe { bindings::phy_init_hw(phydev) })
228     }
229 
230     /// Starts auto-negotiation.
231     pub fn start_aneg(&mut self) -> Result {
232         let phydev = self.0.get();
233         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
234         // So it's just an FFI call.
235         to_result(unsafe { bindings::_phy_start_aneg(phydev) })
236     }
237 
238     /// Resumes the PHY via `BMCR_PDOWN` bit.
239     pub fn genphy_resume(&mut self) -> Result {
240         let phydev = self.0.get();
241         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
242         // So it's just an FFI call.
243         to_result(unsafe { bindings::genphy_resume(phydev) })
244     }
245 
246     /// Suspends the PHY via `BMCR_PDOWN` bit.
247     pub fn genphy_suspend(&mut self) -> Result {
248         let phydev = self.0.get();
249         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
250         // So it's just an FFI call.
251         to_result(unsafe { bindings::genphy_suspend(phydev) })
252     }
253 
254     /// Checks the link status and updates current link state.
255     pub fn genphy_read_status<R: reg::Register>(&mut self) -> Result<u16> {
256         R::read_status(self)
257     }
258 
259     /// Updates the link status.
260     pub fn genphy_update_link(&mut self) -> Result {
261         let phydev = self.0.get();
262         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
263         // So it's just an FFI call.
264         to_result(unsafe { bindings::genphy_update_link(phydev) })
265     }
266 
267     /// Reads link partner ability.
268     pub fn genphy_read_lpa(&mut self) -> Result {
269         let phydev = self.0.get();
270         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
271         // So it's just an FFI call.
272         to_result(unsafe { bindings::genphy_read_lpa(phydev) })
273     }
274 
275     /// Reads PHY abilities.
276     pub fn genphy_read_abilities(&mut self) -> Result {
277         let phydev = self.0.get();
278         // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
279         // So it's just an FFI call.
280         to_result(unsafe { bindings::genphy_read_abilities(phydev) })
281     }
282 }
283 
284 impl AsRef<kernel::device::Device> for Device {
285     fn as_ref(&self) -> &kernel::device::Device {
286         let phydev = self.0.get();
287         // SAFETY: The struct invariant ensures that `mdio.dev` is valid.
288         unsafe { kernel::device::Device::as_ref(addr_of_mut!((*phydev).mdio.dev)) }
289     }
290 }
291 
292 /// Defines certain other features this PHY supports (like interrupts).
293 ///
294 /// These flag values are used in [`Driver::FLAGS`].
295 pub mod flags {
296     /// PHY is internal.
297     pub const IS_INTERNAL: u32 = bindings::PHY_IS_INTERNAL;
298     /// PHY needs to be reset after the refclk is enabled.
299     pub const RST_AFTER_CLK_EN: u32 = bindings::PHY_RST_AFTER_CLK_EN;
300     /// Polling is used to detect PHY status changes.
301     pub const POLL_CABLE_TEST: u32 = bindings::PHY_POLL_CABLE_TEST;
302     /// Don't suspend.
303     pub const ALWAYS_CALL_SUSPEND: u32 = bindings::PHY_ALWAYS_CALL_SUSPEND;
304 }
305 
306 /// An adapter for the registration of a PHY driver.
307 struct Adapter<T: Driver> {
308     _p: PhantomData<T>,
309 }
310 
311 impl<T: Driver> Adapter<T> {
312     /// # Safety
313     ///
314     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
315     unsafe extern "C" fn soft_reset_callback(
316         phydev: *mut bindings::phy_device,
317     ) -> core::ffi::c_int {
318         from_result(|| {
319             // SAFETY: This callback is called only in contexts
320             // where we hold `phy_device->lock`, so the accessors on
321             // `Device` are okay to call.
322             let dev = unsafe { Device::from_raw(phydev) };
323             T::soft_reset(dev)?;
324             Ok(0)
325         })
326     }
327 
328     /// # Safety
329     ///
330     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
331     unsafe extern "C" fn probe_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
332         from_result(|| {
333             // SAFETY: This callback is called only in contexts
334             // where we can exclusively access `phy_device` because
335             // it's not published yet, so the accessors on `Device` are okay
336             // to call.
337             let dev = unsafe { Device::from_raw(phydev) };
338             T::probe(dev)?;
339             Ok(0)
340         })
341     }
342 
343     /// # Safety
344     ///
345     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
346     unsafe extern "C" fn get_features_callback(
347         phydev: *mut bindings::phy_device,
348     ) -> core::ffi::c_int {
349         from_result(|| {
350             // SAFETY: This callback is called only in contexts
351             // where we hold `phy_device->lock`, so the accessors on
352             // `Device` are okay to call.
353             let dev = unsafe { Device::from_raw(phydev) };
354             T::get_features(dev)?;
355             Ok(0)
356         })
357     }
358 
359     /// # Safety
360     ///
361     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
362     unsafe extern "C" fn suspend_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
363         from_result(|| {
364             // SAFETY: The C core code ensures that the accessors on
365             // `Device` are okay to call even though `phy_device->lock`
366             // might not be held.
367             let dev = unsafe { Device::from_raw(phydev) };
368             T::suspend(dev)?;
369             Ok(0)
370         })
371     }
372 
373     /// # Safety
374     ///
375     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
376     unsafe extern "C" fn resume_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
377         from_result(|| {
378             // SAFETY: The C core code ensures that the accessors on
379             // `Device` are okay to call even though `phy_device->lock`
380             // might not be held.
381             let dev = unsafe { Device::from_raw(phydev) };
382             T::resume(dev)?;
383             Ok(0)
384         })
385     }
386 
387     /// # Safety
388     ///
389     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
390     unsafe extern "C" fn config_aneg_callback(
391         phydev: *mut bindings::phy_device,
392     ) -> core::ffi::c_int {
393         from_result(|| {
394             // SAFETY: This callback is called only in contexts
395             // where we hold `phy_device->lock`, so the accessors on
396             // `Device` are okay to call.
397             let dev = unsafe { Device::from_raw(phydev) };
398             T::config_aneg(dev)?;
399             Ok(0)
400         })
401     }
402 
403     /// # Safety
404     ///
405     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
406     unsafe extern "C" fn read_status_callback(
407         phydev: *mut bindings::phy_device,
408     ) -> core::ffi::c_int {
409         from_result(|| {
410             // SAFETY: This callback is called only in contexts
411             // where we hold `phy_device->lock`, so the accessors on
412             // `Device` are okay to call.
413             let dev = unsafe { Device::from_raw(phydev) };
414             T::read_status(dev)?;
415             Ok(0)
416         })
417     }
418 
419     /// # Safety
420     ///
421     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
422     unsafe extern "C" fn match_phy_device_callback(
423         phydev: *mut bindings::phy_device,
424     ) -> core::ffi::c_int {
425         // SAFETY: This callback is called only in contexts
426         // where we hold `phy_device->lock`, so the accessors on
427         // `Device` are okay to call.
428         let dev = unsafe { Device::from_raw(phydev) };
429         T::match_phy_device(dev) as i32
430     }
431 
432     /// # Safety
433     ///
434     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
435     unsafe extern "C" fn read_mmd_callback(
436         phydev: *mut bindings::phy_device,
437         devnum: i32,
438         regnum: u16,
439     ) -> i32 {
440         from_result(|| {
441             // SAFETY: This callback is called only in contexts
442             // where we hold `phy_device->lock`, so the accessors on
443             // `Device` are okay to call.
444             let dev = unsafe { Device::from_raw(phydev) };
445             // CAST: the C side verifies devnum < 32.
446             let ret = T::read_mmd(dev, devnum as u8, regnum)?;
447             Ok(ret.into())
448         })
449     }
450 
451     /// # Safety
452     ///
453     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
454     unsafe extern "C" fn write_mmd_callback(
455         phydev: *mut bindings::phy_device,
456         devnum: i32,
457         regnum: u16,
458         val: u16,
459     ) -> i32 {
460         from_result(|| {
461             // SAFETY: This callback is called only in contexts
462             // where we hold `phy_device->lock`, so the accessors on
463             // `Device` are okay to call.
464             let dev = unsafe { Device::from_raw(phydev) };
465             T::write_mmd(dev, devnum as u8, regnum, val)?;
466             Ok(0)
467         })
468     }
469 
470     /// # Safety
471     ///
472     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
473     unsafe extern "C" fn link_change_notify_callback(phydev: *mut bindings::phy_device) {
474         // SAFETY: This callback is called only in contexts
475         // where we hold `phy_device->lock`, so the accessors on
476         // `Device` are okay to call.
477         let dev = unsafe { Device::from_raw(phydev) };
478         T::link_change_notify(dev);
479     }
480 }
481 
482 /// Driver structure for a particular PHY type.
483 ///
484 /// Wraps the kernel's [`struct phy_driver`].
485 /// This is used to register a driver for a particular PHY type with the kernel.
486 ///
487 /// # Invariants
488 ///
489 /// `self.0` is always in a valid state.
490 ///
491 /// [`struct phy_driver`]: srctree/include/linux/phy.h
492 #[repr(transparent)]
493 pub struct DriverVTable(Opaque<bindings::phy_driver>);
494 
495 // SAFETY: `DriverVTable` doesn't expose any &self method to access internal data, so it's safe to
496 // share `&DriverVTable` across execution context boundaries.
497 unsafe impl Sync for DriverVTable {}
498 
499 /// Creates a [`DriverVTable`] instance from [`Driver`].
500 ///
501 /// This is used by [`module_phy_driver`] macro to create a static array of `phy_driver`.
502 ///
503 /// [`module_phy_driver`]: crate::module_phy_driver
504 pub const fn create_phy_driver<T: Driver>() -> DriverVTable {
505     // INVARIANT: All the fields of `struct phy_driver` are initialized properly.
506     DriverVTable(Opaque::new(bindings::phy_driver {
507         name: T::NAME.as_char_ptr().cast_mut(),
508         flags: T::FLAGS,
509         phy_id: T::PHY_DEVICE_ID.id,
510         phy_id_mask: T::PHY_DEVICE_ID.mask_as_int(),
511         soft_reset: if T::HAS_SOFT_RESET {
512             Some(Adapter::<T>::soft_reset_callback)
513         } else {
514             None
515         },
516         probe: if T::HAS_PROBE {
517             Some(Adapter::<T>::probe_callback)
518         } else {
519             None
520         },
521         get_features: if T::HAS_GET_FEATURES {
522             Some(Adapter::<T>::get_features_callback)
523         } else {
524             None
525         },
526         match_phy_device: if T::HAS_MATCH_PHY_DEVICE {
527             Some(Adapter::<T>::match_phy_device_callback)
528         } else {
529             None
530         },
531         suspend: if T::HAS_SUSPEND {
532             Some(Adapter::<T>::suspend_callback)
533         } else {
534             None
535         },
536         resume: if T::HAS_RESUME {
537             Some(Adapter::<T>::resume_callback)
538         } else {
539             None
540         },
541         config_aneg: if T::HAS_CONFIG_ANEG {
542             Some(Adapter::<T>::config_aneg_callback)
543         } else {
544             None
545         },
546         read_status: if T::HAS_READ_STATUS {
547             Some(Adapter::<T>::read_status_callback)
548         } else {
549             None
550         },
551         read_mmd: if T::HAS_READ_MMD {
552             Some(Adapter::<T>::read_mmd_callback)
553         } else {
554             None
555         },
556         write_mmd: if T::HAS_WRITE_MMD {
557             Some(Adapter::<T>::write_mmd_callback)
558         } else {
559             None
560         },
561         link_change_notify: if T::HAS_LINK_CHANGE_NOTIFY {
562             Some(Adapter::<T>::link_change_notify_callback)
563         } else {
564             None
565         },
566         // SAFETY: The rest is zeroed out to initialize `struct phy_driver`,
567         // sets `Option<&F>` to be `None`.
568         ..unsafe { core::mem::MaybeUninit::<bindings::phy_driver>::zeroed().assume_init() }
569     }))
570 }
571 
572 /// Driver implementation for a particular PHY type.
573 ///
574 /// This trait is used to create a [`DriverVTable`].
575 #[vtable]
576 pub trait Driver {
577     /// Defines certain other features this PHY supports.
578     /// It is a combination of the flags in the [`flags`] module.
579     const FLAGS: u32 = 0;
580 
581     /// The friendly name of this PHY type.
582     const NAME: &'static CStr;
583 
584     /// This driver only works for PHYs with IDs which match this field.
585     /// The default id and mask are zero.
586     const PHY_DEVICE_ID: DeviceId = DeviceId::new_with_custom_mask(0, 0);
587 
588     /// Issues a PHY software reset.
589     fn soft_reset(_dev: &mut Device) -> Result {
590         kernel::build_error(VTABLE_DEFAULT_ERROR)
591     }
592 
593     /// Sets up device-specific structures during discovery.
594     fn probe(_dev: &mut Device) -> Result {
595         kernel::build_error(VTABLE_DEFAULT_ERROR)
596     }
597 
598     /// Probes the hardware to determine what abilities it has.
599     fn get_features(_dev: &mut Device) -> Result {
600         kernel::build_error(VTABLE_DEFAULT_ERROR)
601     }
602 
603     /// Returns true if this is a suitable driver for the given phydev.
604     /// If not implemented, matching is based on [`Driver::PHY_DEVICE_ID`].
605     fn match_phy_device(_dev: &Device) -> bool {
606         false
607     }
608 
609     /// Configures the advertisement and resets auto-negotiation
610     /// if auto-negotiation is enabled.
611     fn config_aneg(_dev: &mut Device) -> Result {
612         kernel::build_error(VTABLE_DEFAULT_ERROR)
613     }
614 
615     /// Determines the negotiated speed and duplex.
616     fn read_status(_dev: &mut Device) -> Result<u16> {
617         kernel::build_error(VTABLE_DEFAULT_ERROR)
618     }
619 
620     /// Suspends the hardware, saving state if needed.
621     fn suspend(_dev: &mut Device) -> Result {
622         kernel::build_error(VTABLE_DEFAULT_ERROR)
623     }
624 
625     /// Resumes the hardware, restoring state if needed.
626     fn resume(_dev: &mut Device) -> Result {
627         kernel::build_error(VTABLE_DEFAULT_ERROR)
628     }
629 
630     /// Overrides the default MMD read function for reading a MMD register.
631     fn read_mmd(_dev: &mut Device, _devnum: u8, _regnum: u16) -> Result<u16> {
632         kernel::build_error(VTABLE_DEFAULT_ERROR)
633     }
634 
635     /// Overrides the default MMD write function for writing a MMD register.
636     fn write_mmd(_dev: &mut Device, _devnum: u8, _regnum: u16, _val: u16) -> Result {
637         kernel::build_error(VTABLE_DEFAULT_ERROR)
638     }
639 
640     /// Callback for notification of link change.
641     fn link_change_notify(_dev: &mut Device) {}
642 }
643 
644 /// Registration structure for PHY drivers.
645 ///
646 /// Registers [`DriverVTable`] instances with the kernel. They will be unregistered when dropped.
647 ///
648 /// # Invariants
649 ///
650 /// The `drivers` slice are currently registered to the kernel via `phy_drivers_register`.
651 pub struct Registration {
652     drivers: Pin<&'static mut [DriverVTable]>,
653 }
654 
655 // SAFETY: The only action allowed in a `Registration` instance is dropping it, which is safe to do
656 // from any thread because `phy_drivers_unregister` can be called from any thread context.
657 unsafe impl Send for Registration {}
658 
659 impl Registration {
660     /// Registers a PHY driver.
661     pub fn register(
662         module: &'static crate::ThisModule,
663         drivers: Pin<&'static mut [DriverVTable]>,
664     ) -> Result<Self> {
665         if drivers.is_empty() {
666             return Err(code::EINVAL);
667         }
668         // SAFETY: The type invariants of [`DriverVTable`] ensure that all elements of
669         // the `drivers` slice are initialized properly. `drivers` will not be moved.
670         // So it's just an FFI call.
671         to_result(unsafe {
672             bindings::phy_drivers_register(drivers[0].0.get(), drivers.len().try_into()?, module.0)
673         })?;
674         // INVARIANT: The `drivers` slice is successfully registered to the kernel via `phy_drivers_register`.
675         Ok(Registration { drivers })
676     }
677 }
678 
679 impl Drop for Registration {
680     fn drop(&mut self) {
681         // SAFETY: The type invariants guarantee that `self.drivers` is valid.
682         // So it's just an FFI call.
683         unsafe {
684             bindings::phy_drivers_unregister(self.drivers[0].0.get(), self.drivers.len() as i32)
685         };
686     }
687 }
688 
689 /// An identifier for PHY devices on an MDIO/MII bus.
690 ///
691 /// Represents the kernel's `struct mdio_device_id`. This is used to find an appropriate
692 /// PHY driver.
693 pub struct DeviceId {
694     id: u32,
695     mask: DeviceMask,
696 }
697 
698 impl DeviceId {
699     /// Creates a new instance with the exact match mask.
700     pub const fn new_with_exact_mask(id: u32) -> Self {
701         DeviceId {
702             id,
703             mask: DeviceMask::Exact,
704         }
705     }
706 
707     /// Creates a new instance with the model match mask.
708     pub const fn new_with_model_mask(id: u32) -> Self {
709         DeviceId {
710             id,
711             mask: DeviceMask::Model,
712         }
713     }
714 
715     /// Creates a new instance with the vendor match mask.
716     pub const fn new_with_vendor_mask(id: u32) -> Self {
717         DeviceId {
718             id,
719             mask: DeviceMask::Vendor,
720         }
721     }
722 
723     /// Creates a new instance with a custom match mask.
724     pub const fn new_with_custom_mask(id: u32, mask: u32) -> Self {
725         DeviceId {
726             id,
727             mask: DeviceMask::Custom(mask),
728         }
729     }
730 
731     /// Creates a new instance from [`Driver`].
732     pub const fn new_with_driver<T: Driver>() -> Self {
733         T::PHY_DEVICE_ID
734     }
735 
736     /// Get a `mask` as u32.
737     pub const fn mask_as_int(&self) -> u32 {
738         self.mask.as_int()
739     }
740 
741     // macro use only
742     #[doc(hidden)]
743     pub const fn mdio_device_id(&self) -> bindings::mdio_device_id {
744         bindings::mdio_device_id {
745             phy_id: self.id,
746             phy_id_mask: self.mask.as_int(),
747         }
748     }
749 }
750 
751 enum DeviceMask {
752     Exact,
753     Model,
754     Vendor,
755     Custom(u32),
756 }
757 
758 impl DeviceMask {
759     const MASK_EXACT: u32 = !0;
760     const MASK_MODEL: u32 = !0 << 4;
761     const MASK_VENDOR: u32 = !0 << 10;
762 
763     const fn as_int(&self) -> u32 {
764         match self {
765             DeviceMask::Exact => Self::MASK_EXACT,
766             DeviceMask::Model => Self::MASK_MODEL,
767             DeviceMask::Vendor => Self::MASK_VENDOR,
768             DeviceMask::Custom(mask) => *mask,
769         }
770     }
771 }
772 
773 /// Declares a kernel module for PHYs drivers.
774 ///
775 /// This creates a static array of kernel's `struct phy_driver` and registers it.
776 /// This also corresponds to the kernel's `MODULE_DEVICE_TABLE` macro, which embeds the information
777 /// for module loading into the module binary file. Every driver needs an entry in `device_table`.
778 ///
779 /// # Examples
780 ///
781 /// ```
782 /// # mod module_phy_driver_sample {
783 /// use kernel::c_str;
784 /// use kernel::net::phy::{self, DeviceId};
785 /// use kernel::prelude::*;
786 ///
787 /// kernel::module_phy_driver! {
788 ///     drivers: [PhySample],
789 ///     device_table: [
790 ///         DeviceId::new_with_driver::<PhySample>()
791 ///     ],
792 ///     name: "rust_sample_phy",
793 ///     author: "Rust for Linux Contributors",
794 ///     description: "Rust sample PHYs driver",
795 ///     license: "GPL",
796 /// }
797 ///
798 /// struct PhySample;
799 ///
800 /// #[vtable]
801 /// impl phy::Driver for PhySample {
802 ///     const NAME: &'static CStr = c_str!("PhySample");
803 ///     const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x00000001);
804 /// }
805 /// # }
806 /// ```
807 ///
808 /// This expands to the following code:
809 ///
810 /// ```ignore
811 /// use kernel::c_str;
812 /// use kernel::net::phy::{self, DeviceId};
813 /// use kernel::prelude::*;
814 ///
815 /// struct Module {
816 ///     _reg: ::kernel::net::phy::Registration,
817 /// }
818 ///
819 /// module! {
820 ///     type: Module,
821 ///     name: "rust_sample_phy",
822 ///     author: "Rust for Linux Contributors",
823 ///     description: "Rust sample PHYs driver",
824 ///     license: "GPL",
825 /// }
826 ///
827 /// struct PhySample;
828 ///
829 /// #[vtable]
830 /// impl phy::Driver for PhySample {
831 ///     const NAME: &'static CStr = c_str!("PhySample");
832 ///     const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x00000001);
833 /// }
834 ///
835 /// const _: () = {
836 ///     static mut DRIVERS: [::kernel::net::phy::DriverVTable; 1] =
837 ///         [::kernel::net::phy::create_phy_driver::<PhySample>()];
838 ///
839 ///     impl ::kernel::Module for Module {
840 ///         fn init(module: &'static ThisModule) -> Result<Self> {
841 ///             let drivers = unsafe { &mut DRIVERS };
842 ///             let mut reg = ::kernel::net::phy::Registration::register(
843 ///                 module,
844 ///                 ::core::pin::Pin::static_mut(drivers),
845 ///             )?;
846 ///             Ok(Module { _reg: reg })
847 ///         }
848 ///     }
849 /// };
850 ///
851 /// #[cfg(MODULE)]
852 /// #[no_mangle]
853 /// static __mod_mdio__phydev_device_table: [::kernel::bindings::mdio_device_id; 2] = [
854 ///     ::kernel::bindings::mdio_device_id {
855 ///         phy_id: 0x00000001,
856 ///         phy_id_mask: 0xffffffff,
857 ///     },
858 ///     ::kernel::bindings::mdio_device_id {
859 ///         phy_id: 0,
860 ///         phy_id_mask: 0,
861 ///     },
862 /// ];
863 /// ```
864 #[macro_export]
865 macro_rules! module_phy_driver {
866     (@replace_expr $_t:tt $sub:expr) => {$sub};
867 
868     (@count_devices $($x:expr),*) => {
869         0usize $(+ $crate::module_phy_driver!(@replace_expr $x 1usize))*
870     };
871 
872     (@device_table [$($dev:expr),+]) => {
873         // SAFETY: C will not read off the end of this constant since the last element is zero.
874         #[cfg(MODULE)]
875         #[no_mangle]
876         static __mod_mdio__phydev_device_table: [$crate::bindings::mdio_device_id;
877             $crate::module_phy_driver!(@count_devices $($dev),+) + 1] = [
878             $($dev.mdio_device_id()),+,
879             $crate::bindings::mdio_device_id {
880                 phy_id: 0,
881                 phy_id_mask: 0
882             }
883         ];
884     };
885 
886     (drivers: [$($driver:ident),+ $(,)?], device_table: [$($dev:expr),+ $(,)?], $($f:tt)*) => {
887         struct Module {
888             _reg: $crate::net::phy::Registration,
889         }
890 
891         $crate::prelude::module! {
892             type: Module,
893             $($f)*
894         }
895 
896         const _: () = {
897             static mut DRIVERS: [$crate::net::phy::DriverVTable;
898                 $crate::module_phy_driver!(@count_devices $($driver),+)] =
899                 [$($crate::net::phy::create_phy_driver::<$driver>()),+];
900 
901             impl $crate::Module for Module {
902                 fn init(module: &'static ThisModule) -> Result<Self> {
903                     // SAFETY: The anonymous constant guarantees that nobody else can access
904                     // the `DRIVERS` static. The array is used only in the C side.
905                     let drivers = unsafe { &mut DRIVERS };
906                     let mut reg = $crate::net::phy::Registration::register(
907                         module,
908                         ::core::pin::Pin::static_mut(drivers),
909                     )?;
910                     Ok(Module { _reg: reg })
911                 }
912             }
913         };
914 
915         $crate::module_phy_driver!(@device_table [$($dev),+]);
916     }
917 }
918