summaryrefslogtreecommitdiff
path: root/rust/kernel/net/phy.rs
blob: 265d0e1c13710a53a9f9d0b5af12b24402eb4741 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
// SPDX-License-Identifier: GPL-2.0

// Copyright (C) 2023 FUJITA Tomonori <fujita.tomonori@gmail.com>

//! Network PHY device.
//!
//! C headers: [`include/linux/phy.h`](srctree/include/linux/phy.h).

use crate::{bindings, error::*, prelude::*, str::CStr, types::Opaque};

use core::marker::PhantomData;

/// PHY state machine states.
///
/// Corresponds to the kernel's [`enum phy_state`].
///
/// Some of PHY drivers access to the state of PHY's software state machine.
///
/// [`enum phy_state`]: srctree/include/linux/phy.h
#[derive(PartialEq, Eq)]
pub enum DeviceState {
    /// PHY device and driver are not ready for anything.
    Down,
    /// PHY is ready to send and receive packets.
    Ready,
    /// PHY is up, but no polling or interrupts are done.
    Halted,
    /// PHY is up, but is in an error state.
    Error,
    /// PHY and attached device are ready to do work.
    Up,
    /// PHY is currently running.
    Running,
    /// PHY is up, but not currently plugged in.
    NoLink,
    /// PHY is performing a cable test.
    CableTest,
}

/// A mode of Ethernet communication.
///
/// PHY drivers get duplex information from hardware and update the current state.
pub enum DuplexMode {
    /// PHY is in full-duplex mode.
    Full,
    /// PHY is in half-duplex mode.
    Half,
    /// PHY is in unknown duplex mode.
    Unknown,
}

/// An instance of a PHY device.
///
/// Wraps the kernel's [`struct phy_device`].
///
/// A [`Device`] instance is created when a callback in [`Driver`] is executed. A PHY driver
/// executes [`Driver`]'s methods during the callback.
///
/// # Invariants
///
/// Referencing a `phy_device` using this struct asserts that you are in
/// a context where all methods defined on this struct are safe to call.
///
/// [`struct phy_device`]: srctree/include/linux/phy.h
// During the calls to most functions in [`Driver`], the C side (`PHYLIB`) holds a lock that is
// unique for every instance of [`Device`]. `PHYLIB` uses a different serialization technique for
// [`Driver::resume`] and [`Driver::suspend`]: `PHYLIB` updates `phy_device`'s state with
// the lock held, thus guaranteeing that [`Driver::resume`] has exclusive access to the instance.
// [`Driver::resume`] and [`Driver::suspend`] also are called where only one thread can access
// to the instance.
#[repr(transparent)]
pub struct Device(Opaque<bindings::phy_device>);

impl Device {
    /// Creates a new [`Device`] instance from a raw pointer.
    ///
    /// # Safety
    ///
    /// For the duration of 'a, the pointer must point at a valid `phy_device`,
    /// and the caller must be in a context where all methods defined on this struct
    /// are safe to call.
    unsafe fn from_raw<'a>(ptr: *mut bindings::phy_device) -> &'a mut Self {
        // CAST: `Self` is a `repr(transparent)` wrapper around `bindings::phy_device`.
        let ptr = ptr.cast::<Self>();
        // SAFETY: by the function requirements the pointer is valid and we have unique access for
        // the duration of `'a`.
        unsafe { &mut *ptr }
    }

    /// Gets the id of the PHY.
    pub fn phy_id(&self) -> u32 {
        let phydev = self.0.get();
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        unsafe { (*phydev).phy_id }
    }

    /// Gets the state of PHY state machine states.
    pub fn state(&self) -> DeviceState {
        let phydev = self.0.get();
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        let state = unsafe { (*phydev).state };
        // TODO: this conversion code will be replaced with automatically generated code by bindgen
        // when it becomes possible.
        match state {
            bindings::phy_state_PHY_DOWN => DeviceState::Down,
            bindings::phy_state_PHY_READY => DeviceState::Ready,
            bindings::phy_state_PHY_HALTED => DeviceState::Halted,
            bindings::phy_state_PHY_ERROR => DeviceState::Error,
            bindings::phy_state_PHY_UP => DeviceState::Up,
            bindings::phy_state_PHY_RUNNING => DeviceState::Running,
            bindings::phy_state_PHY_NOLINK => DeviceState::NoLink,
            bindings::phy_state_PHY_CABLETEST => DeviceState::CableTest,
            _ => DeviceState::Error,
        }
    }

    /// Gets the current link state.
    ///
    /// It returns true if the link is up.
    pub fn is_link_up(&self) -> bool {
        const LINK_IS_UP: u64 = 1;
        // TODO: the code to access to the bit field will be replaced with automatically
        // generated code by bindgen when it becomes possible.
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
        bit_field.get(14, 1) == LINK_IS_UP
    }

    /// Gets the current auto-negotiation configuration.
    ///
    /// It returns true if auto-negotiation is enabled.
    pub fn is_autoneg_enabled(&self) -> bool {
        // TODO: the code to access to the bit field will be replaced with automatically
        // generated code by bindgen when it becomes possible.
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
        bit_field.get(13, 1) == bindings::AUTONEG_ENABLE as u64
    }

    /// Gets the current auto-negotiation state.
    ///
    /// It returns true if auto-negotiation is completed.
    pub fn is_autoneg_completed(&self) -> bool {
        const AUTONEG_COMPLETED: u64 = 1;
        // TODO: the code to access to the bit field will be replaced with automatically
        // generated code by bindgen when it becomes possible.
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
        bit_field.get(15, 1) == AUTONEG_COMPLETED
    }

    /// Sets the speed of the PHY.
    pub fn set_speed(&mut self, speed: u32) {
        let phydev = self.0.get();
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        unsafe { (*phydev).speed = speed as i32 };
    }

    /// Sets duplex mode.
    pub fn set_duplex(&mut self, mode: DuplexMode) {
        let phydev = self.0.get();
        let v = match mode {
            DuplexMode::Full => bindings::DUPLEX_FULL as i32,
            DuplexMode::Half => bindings::DUPLEX_HALF as i32,
            DuplexMode::Unknown => bindings::DUPLEX_UNKNOWN as i32,
        };
        // SAFETY: The struct invariant ensures that we may access
        // this field without additional synchronization.
        unsafe { (*phydev).duplex = v };
    }

    /// Reads a given C22 PHY register.
    // This function reads a hardware register and updates the stats so takes `&mut self`.
    pub fn read(&mut self, regnum: u16) -> Result<u16> {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call, open code of `phy_read()` with a valid `phy_device` pointer
        // `phydev`.
        let ret = unsafe {
            bindings::mdiobus_read((*phydev).mdio.bus, (*phydev).mdio.addr, regnum.into())
        };
        if ret < 0 {
            Err(Error::from_errno(ret))
        } else {
            Ok(ret as u16)
        }
    }

    /// Writes a given C22 PHY register.
    pub fn write(&mut self, regnum: u16, val: u16) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call, open code of `phy_write()` with a valid `phy_device` pointer
        // `phydev`.
        to_result(unsafe {
            bindings::mdiobus_write((*phydev).mdio.bus, (*phydev).mdio.addr, regnum.into(), val)
        })
    }

    /// Reads a paged register.
    pub fn read_paged(&mut self, page: u16, regnum: u16) -> Result<u16> {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        let ret = unsafe { bindings::phy_read_paged(phydev, page.into(), regnum.into()) };
        if ret < 0 {
            Err(Error::from_errno(ret))
        } else {
            Ok(ret as u16)
        }
    }

    /// Resolves the advertisements into PHY settings.
    pub fn resolve_aneg_linkmode(&mut self) {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        unsafe { bindings::phy_resolve_aneg_linkmode(phydev) };
    }

    /// Executes software reset the PHY via `BMCR_RESET` bit.
    pub fn genphy_soft_reset(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::genphy_soft_reset(phydev) })
    }

    /// Initializes the PHY.
    pub fn init_hw(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::phy_init_hw(phydev) })
    }

    /// Starts auto-negotiation.
    pub fn start_aneg(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::_phy_start_aneg(phydev) })
    }

    /// Resumes the PHY via `BMCR_PDOWN` bit.
    pub fn genphy_resume(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::genphy_resume(phydev) })
    }

    /// Suspends the PHY via `BMCR_PDOWN` bit.
    pub fn genphy_suspend(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::genphy_suspend(phydev) })
    }

    /// Checks the link status and updates current link state.
    pub fn genphy_read_status(&mut self) -> Result<u16> {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        let ret = unsafe { bindings::genphy_read_status(phydev) };
        if ret < 0 {
            Err(Error::from_errno(ret))
        } else {
            Ok(ret as u16)
        }
    }

    /// Updates the link status.
    pub fn genphy_update_link(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::genphy_update_link(phydev) })
    }

    /// Reads link partner ability.
    pub fn genphy_read_lpa(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::genphy_read_lpa(phydev) })
    }

    /// Reads PHY abilities.
    pub fn genphy_read_abilities(&mut self) -> Result {
        let phydev = self.0.get();
        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`.
        // So it's just an FFI call.
        to_result(unsafe { bindings::genphy_read_abilities(phydev) })
    }
}

/// Defines certain other features this PHY supports (like interrupts).
///
/// These flag values are used in [`Driver::FLAGS`].
pub mod flags {
    /// PHY is internal.
    pub const IS_INTERNAL: u32 = bindings::PHY_IS_INTERNAL;
    /// PHY needs to be reset after the refclk is enabled.
    pub const RST_AFTER_CLK_EN: u32 = bindings::PHY_RST_AFTER_CLK_EN;
    /// Polling is used to detect PHY status changes.
    pub const POLL_CABLE_TEST: u32 = bindings::PHY_POLL_CABLE_TEST;
    /// Don't suspend.
    pub const ALWAYS_CALL_SUSPEND: u32 = bindings::PHY_ALWAYS_CALL_SUSPEND;
}

/// An adapter for the registration of a PHY driver.
struct Adapter<T: Driver> {
    _p: PhantomData<T>,
}

impl<T: Driver> Adapter<T> {
    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn soft_reset_callback(
        phydev: *mut bindings::phy_device,
    ) -> core::ffi::c_int {
        from_result(|| {
            // SAFETY: This callback is called only in contexts
            // where we hold `phy_device->lock`, so the accessors on
            // `Device` are okay to call.
            let dev = unsafe { Device::from_raw(phydev) };
            T::soft_reset(dev)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn get_features_callback(
        phydev: *mut bindings::phy_device,
    ) -> core::ffi::c_int {
        from_result(|| {
            // SAFETY: This callback is called only in contexts
            // where we hold `phy_device->lock`, so the accessors on
            // `Device` are okay to call.
            let dev = unsafe { Device::from_raw(phydev) };
            T::get_features(dev)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn suspend_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
        from_result(|| {
            // SAFETY: The C core code ensures that the accessors on
            // `Device` are okay to call even though `phy_device->lock`
            // might not be held.
            let dev = unsafe { Device::from_raw(phydev) };
            T::suspend(dev)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn resume_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
        from_result(|| {
            // SAFETY: The C core code ensures that the accessors on
            // `Device` are okay to call even though `phy_device->lock`
            // might not be held.
            let dev = unsafe { Device::from_raw(phydev) };
            T::resume(dev)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn config_aneg_callback(
        phydev: *mut bindings::phy_device,
    ) -> core::ffi::c_int {
        from_result(|| {
            // SAFETY: This callback is called only in contexts
            // where we hold `phy_device->lock`, so the accessors on
            // `Device` are okay to call.
            let dev = unsafe { Device::from_raw(phydev) };
            T::config_aneg(dev)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn read_status_callback(
        phydev: *mut bindings::phy_device,
    ) -> core::ffi::c_int {
        from_result(|| {
            // SAFETY: This callback is called only in contexts
            // where we hold `phy_device->lock`, so the accessors on
            // `Device` are okay to call.
            let dev = unsafe { Device::from_raw(phydev) };
            T::read_status(dev)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn match_phy_device_callback(
        phydev: *mut bindings::phy_device,
    ) -> core::ffi::c_int {
        // SAFETY: This callback is called only in contexts
        // where we hold `phy_device->lock`, so the accessors on
        // `Device` are okay to call.
        let dev = unsafe { Device::from_raw(phydev) };
        T::match_phy_device(dev) as i32
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn read_mmd_callback(
        phydev: *mut bindings::phy_device,
        devnum: i32,
        regnum: u16,
    ) -> i32 {
        from_result(|| {
            // SAFETY: This callback is called only in contexts
            // where we hold `phy_device->lock`, so the accessors on
            // `Device` are okay to call.
            let dev = unsafe { Device::from_raw(phydev) };
            // CAST: the C side verifies devnum < 32.
            let ret = T::read_mmd(dev, devnum as u8, regnum)?;
            Ok(ret.into())
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn write_mmd_callback(
        phydev: *mut bindings::phy_device,
        devnum: i32,
        regnum: u16,
        val: u16,
    ) -> i32 {
        from_result(|| {
            // SAFETY: This callback is called only in contexts
            // where we hold `phy_device->lock`, so the accessors on
            // `Device` are okay to call.
            let dev = unsafe { Device::from_raw(phydev) };
            T::write_mmd(dev, devnum as u8, regnum, val)?;
            Ok(0)
        })
    }

    /// # Safety
    ///
    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
    unsafe extern "C" fn link_change_notify_callback(phydev: *mut bindings::phy_device) {
        // SAFETY: This callback is called only in contexts
        // where we hold `phy_device->lock`, so the accessors on
        // `Device` are okay to call.
        let dev = unsafe { Device::from_raw(phydev) };
        T::link_change_notify(dev);
    }
}

/// Driver structure for a particular PHY type.
///
/// Wraps the kernel's [`struct phy_driver`].
/// This is used to register a driver for a particular PHY type with the kernel.
///
/// # Invariants
///
/// `self.0` is always in a valid state.
///
/// [`struct phy_driver`]: srctree/include/linux/phy.h
#[repr(transparent)]
pub struct DriverVTable(Opaque<bindings::phy_driver>);

// SAFETY: `DriverVTable` doesn't expose any &self method to access internal data, so it's safe to
// share `&DriverVTable` across execution context boundries.
unsafe impl Sync for DriverVTable {}

/// Creates a [`DriverVTable`] instance from [`Driver`].
///
/// This is used by [`module_phy_driver`] macro to create a static array of `phy_driver`.
///
/// [`module_phy_driver`]: crate::module_phy_driver
pub const fn create_phy_driver<T: Driver>() -> DriverVTable {
    // INVARIANT: All the fields of `struct phy_driver` are initialized properly.
    DriverVTable(Opaque::new(bindings::phy_driver {
        name: T::NAME.as_char_ptr().cast_mut(),
        flags: T::FLAGS,
        phy_id: T::PHY_DEVICE_ID.id,
        phy_id_mask: T::PHY_DEVICE_ID.mask_as_int(),
        soft_reset: if T::HAS_SOFT_RESET {
            Some(Adapter::<T>::soft_reset_callback)
        } else {
            None
        },
        get_features: if T::HAS_GET_FEATURES {
            Some(Adapter::<T>::get_features_callback)
        } else {
            None
        },
        match_phy_device: if T::HAS_MATCH_PHY_DEVICE {
            Some(Adapter::<T>::match_phy_device_callback)
        } else {
            None
        },
        suspend: if T::HAS_SUSPEND {
            Some(Adapter::<T>::suspend_callback)
        } else {
            None
        },
        resume: if T::HAS_RESUME {
            Some(Adapter::<T>::resume_callback)
        } else {
            None
        },
        config_aneg: if T::HAS_CONFIG_ANEG {
            Some(Adapter::<T>::config_aneg_callback)
        } else {
            None
        },
        read_status: if T::HAS_READ_STATUS {
            Some(Adapter::<T>::read_status_callback)
        } else {
            None
        },
        read_mmd: if T::HAS_READ_MMD {
            Some(Adapter::<T>::read_mmd_callback)
        } else {
            None
        },
        write_mmd: if T::HAS_WRITE_MMD {
            Some(Adapter::<T>::write_mmd_callback)
        } else {
            None
        },
        link_change_notify: if T::HAS_LINK_CHANGE_NOTIFY {
            Some(Adapter::<T>::link_change_notify_callback)
        } else {
            None
        },
        // SAFETY: The rest is zeroed out to initialize `struct phy_driver`,
        // sets `Option<&F>` to be `None`.
        ..unsafe { core::mem::MaybeUninit::<bindings::phy_driver>::zeroed().assume_init() }
    }))
}

/// Driver implementation for a particular PHY type.
///
/// This trait is used to create a [`DriverVTable`].
#[vtable]
pub trait Driver {
    /// Defines certain other features this PHY supports.
    /// It is a combination of the flags in the [`flags`] module.
    const FLAGS: u32 = 0;

    /// The friendly name of this PHY type.
    const NAME: &'static CStr;

    /// This driver only works for PHYs with IDs which match this field.
    /// The default id and mask are zero.
    const PHY_DEVICE_ID: DeviceId = DeviceId::new_with_custom_mask(0, 0);

    /// Issues a PHY software reset.
    fn soft_reset(_dev: &mut Device) -> Result {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Probes the hardware to determine what abilities it has.
    fn get_features(_dev: &mut Device) -> Result {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Returns true if this is a suitable driver for the given phydev.
    /// If not implemented, matching is based on [`Driver::PHY_DEVICE_ID`].
    fn match_phy_device(_dev: &Device) -> bool {
        false
    }

    /// Configures the advertisement and resets auto-negotiation
    /// if auto-negotiation is enabled.
    fn config_aneg(_dev: &mut Device) -> Result {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Determines the negotiated speed and duplex.
    fn read_status(_dev: &mut Device) -> Result<u16> {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Suspends the hardware, saving state if needed.
    fn suspend(_dev: &mut Device) -> Result {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Resumes the hardware, restoring state if needed.
    fn resume(_dev: &mut Device) -> Result {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Overrides the default MMD read function for reading a MMD register.
    fn read_mmd(_dev: &mut Device, _devnum: u8, _regnum: u16) -> Result<u16> {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Overrides the default MMD write function for writing a MMD register.
    fn write_mmd(_dev: &mut Device, _devnum: u8, _regnum: u16, _val: u16) -> Result {
        kernel::build_error(VTABLE_DEFAULT_ERROR)
    }

    /// Callback for notification of link change.
    fn link_change_notify(_dev: &mut Device) {}
}

/// Registration structure for PHY drivers.
///
/// Registers [`DriverVTable`] instances with the kernel. They will be unregistered when dropped.
///
/// # Invariants
///
/// The `drivers` slice are currently registered to the kernel via `phy_drivers_register`.
pub struct Registration {
    drivers: Pin<&'static mut [DriverVTable]>,
}

// SAFETY: The only action allowed in a `Registration` instance is dropping it, which is safe to do
// from any thread because `phy_drivers_unregister` can be called from any thread context.
unsafe impl Send for Registration {}

impl Registration {
    /// Registers a PHY driver.
    pub fn register(
        module: &'static crate::ThisModule,
        drivers: Pin<&'static mut [DriverVTable]>,
    ) -> Result<Self> {
        if drivers.is_empty() {
            return Err(code::EINVAL);
        }
        // SAFETY: The type invariants of [`DriverVTable`] ensure that all elements of
        // the `drivers` slice are initialized properly. `drivers` will not be moved.
        // So it's just an FFI call.
        to_result(unsafe {
            bindings::phy_drivers_register(drivers[0].0.get(), drivers.len().try_into()?, module.0)
        })?;
        // INVARIANT: The `drivers` slice is successfully registered to the kernel via `phy_drivers_register`.
        Ok(Registration { drivers })
    }
}

impl Drop for Registration {
    fn drop(&mut self) {
        // SAFETY: The type invariants guarantee that `self.drivers` is valid.
        // So it's just an FFI call.
        unsafe {
            bindings::phy_drivers_unregister(self.drivers[0].0.get(), self.drivers.len() as i32)
        };
    }
}

/// An identifier for PHY devices on an MDIO/MII bus.
///
/// Represents the kernel's `struct mdio_device_id`. This is used to find an appropriate
/// PHY driver.
pub struct DeviceId {
    id: u32,
    mask: DeviceMask,
}

impl DeviceId {
    /// Creates a new instance with the exact match mask.
    pub const fn new_with_exact_mask(id: u32) -> Self {
        DeviceId {
            id,
            mask: DeviceMask::Exact,
        }
    }

    /// Creates a new instance with the model match mask.
    pub const fn new_with_model_mask(id: u32) -> Self {
        DeviceId {
            id,
            mask: DeviceMask::Model,
        }
    }

    /// Creates a new instance with the vendor match mask.
    pub const fn new_with_vendor_mask(id: u32) -> Self {
        DeviceId {
            id,
            mask: DeviceMask::Vendor,
        }
    }

    /// Creates a new instance with a custom match mask.
    pub const fn new_with_custom_mask(id: u32, mask: u32) -> Self {
        DeviceId {
            id,
            mask: DeviceMask::Custom(mask),
        }
    }

    /// Creates a new instance from [`Driver`].
    pub const fn new_with_driver<T: Driver>() -> Self {
        T::PHY_DEVICE_ID
    }

    /// Get a `mask` as u32.
    pub const fn mask_as_int(&self) -> u32 {
        self.mask.as_int()
    }

    // macro use only
    #[doc(hidden)]
    pub const fn mdio_device_id(&self) -> bindings::mdio_device_id {
        bindings::mdio_device_id {
            phy_id: self.id,
            phy_id_mask: self.mask.as_int(),
        }
    }
}

enum DeviceMask {
    Exact,
    Model,
    Vendor,
    Custom(u32),
}

impl DeviceMask {
    const MASK_EXACT: u32 = !0;
    const MASK_MODEL: u32 = !0 << 4;
    const MASK_VENDOR: u32 = !0 << 10;

    const fn as_int(&self) -> u32 {
        match self {
            DeviceMask::Exact => Self::MASK_EXACT,
            DeviceMask::Model => Self::MASK_MODEL,
            DeviceMask::Vendor => Self::MASK_VENDOR,
            DeviceMask::Custom(mask) => *mask,
        }
    }
}

/// Declares a kernel module for PHYs drivers.
///
/// This creates a static array of kernel's `struct phy_driver` and registers it.
/// This also corresponds to the kernel's `MODULE_DEVICE_TABLE` macro, which embeds the information
/// for module loading into the module binary file. Every driver needs an entry in `device_table`.
///
/// # Examples
///
/// ```
/// # mod module_phy_driver_sample {
/// use kernel::c_str;
/// use kernel::net::phy::{self, DeviceId};
/// use kernel::prelude::*;
///
/// kernel::module_phy_driver! {
///     drivers: [PhySample],
///     device_table: [
///         DeviceId::new_with_driver::<PhySample>()
///     ],
///     name: "rust_sample_phy",
///     author: "Rust for Linux Contributors",
///     description: "Rust sample PHYs driver",
///     license: "GPL",
/// }
///
/// struct PhySample;
///
/// #[vtable]
/// impl phy::Driver for PhySample {
///     const NAME: &'static CStr = c_str!("PhySample");
///     const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x00000001);
/// }
/// # }
/// ```
///
/// This expands to the following code:
///
/// ```ignore
/// use kernel::c_str;
/// use kernel::net::phy::{self, DeviceId};
/// use kernel::prelude::*;
///
/// struct Module {
///     _reg: ::kernel::net::phy::Registration,
/// }
///
/// module! {
///     type: Module,
///     name: "rust_sample_phy",
///     author: "Rust for Linux Contributors",
///     description: "Rust sample PHYs driver",
///     license: "GPL",
/// }
///
/// struct PhySample;
///
/// #[vtable]
/// impl phy::Driver for PhySample {
///     const NAME: &'static CStr = c_str!("PhySample");
///     const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x00000001);
/// }
///
/// const _: () = {
///     static mut DRIVERS: [::kernel::net::phy::DriverVTable; 1] =
///         [::kernel::net::phy::create_phy_driver::<PhySample>()];
///
///     impl ::kernel::Module for Module {
///         fn init(module: &'static ThisModule) -> Result<Self> {
///             let drivers = unsafe { &mut DRIVERS };
///             let mut reg = ::kernel::net::phy::Registration::register(
///                 module,
///                 ::core::pin::Pin::static_mut(drivers),
///             )?;
///             Ok(Module { _reg: reg })
///         }
///     }
/// };
///
/// #[cfg(MODULE)]
/// #[no_mangle]
/// static __mod_mdio__phydev_device_table: [::kernel::bindings::mdio_device_id; 2] = [
///     ::kernel::bindings::mdio_device_id {
///         phy_id: 0x00000001,
///         phy_id_mask: 0xffffffff,
///     },
///     ::kernel::bindings::mdio_device_id {
///         phy_id: 0,
///         phy_id_mask: 0,
///     },
/// ];
/// ```
#[macro_export]
macro_rules! module_phy_driver {
    (@replace_expr $_t:tt $sub:expr) => {$sub};

    (@count_devices $($x:expr),*) => {
        0usize $(+ $crate::module_phy_driver!(@replace_expr $x 1usize))*
    };

    (@device_table [$($dev:expr),+]) => {
        // SAFETY: C will not read off the end of this constant since the last element is zero.
        #[cfg(MODULE)]
        #[no_mangle]
        static __mod_mdio__phydev_device_table: [$crate::bindings::mdio_device_id;
            $crate::module_phy_driver!(@count_devices $($dev),+) + 1] = [
            $($dev.mdio_device_id()),+,
            $crate::bindings::mdio_device_id {
                phy_id: 0,
                phy_id_mask: 0
            }
        ];
    };

    (drivers: [$($driver:ident),+ $(,)?], device_table: [$($dev:expr),+ $(,)?], $($f:tt)*) => {
        struct Module {
            _reg: $crate::net::phy::Registration,
        }

        $crate::prelude::module! {
            type: Module,
            $($f)*
        }

        const _: () = {
            static mut DRIVERS: [$crate::net::phy::DriverVTable;
                $crate::module_phy_driver!(@count_devices $($driver),+)] =
                [$($crate::net::phy::create_phy_driver::<$driver>()),+];

            impl $crate::Module for Module {
                fn init(module: &'static ThisModule) -> Result<Self> {
                    // SAFETY: The anonymous constant guarantees that nobody else can access
                    // the `DRIVERS` static. The array is used only in the C side.
                    let drivers = unsafe { &mut DRIVERS };
                    let mut reg = $crate::net::phy::Registration::register(
                        module,
                        ::core::pin::Pin::static_mut(drivers),
                    )?;
                    Ok(Module { _reg: reg })
                }
            }
        };

        $crate::module_phy_driver!(@device_table [$($dev),+]);
    }
}