Merge branch 'am-qt2025-phy-rust'

FUJITA Tomonori says:

====================
net: phy: add Applied Micro QT2025 PHY driver

This patchset adds a PHY driver for Applied Micro Circuits Corporation
QT2025.

The first patch adds Rust equivalent to include/linux/sizes.h, makes
code more readable. The 2-5th patches update the PHYLIB Rust bindings.
The 4th and 5th patches have been reviewed previously in a different
thread [1].

QT2025 PHY support was implemented as a part of an Ethernet driver for
Tehuti Networks TN40xx chips. Multiple vendors (DLink, Asus, Edimax,
QNAP, etc) developed adapters based on TN40xx chips. Tehuti Networks
went out of business and the driver wasn't merged into mainline. But
it's still distributed with some of the hardware (and also available
on some vendor sites).

The original driver handles multiple PHY hardware (AMCC QT2025, TI
TLK10232, Aqrate AQR105, and Marvell MV88X3120, MV88X3310, and
MV88E2010). I divided the original driver into MAC and PHY drivers and
implemented a QT2025 PHY driver in Rust.

The MAC driver for Tehuti Networks TN40xx chips was already merged in
6.11-rc1. The MAC and this PHY drivers have been tested with Edimax
EN-9320SFP+ 10G network adapter.

[1] https://lore.kernel.org/rust-for-linux/[email protected]/

v7:
- add Trevor as Reviewer to MAINTAINERS file entry
- add Trevor Reviewed-by
- add/fix comments
- replace uppercase hex with lowercase
- remove unnecessary code
- update the commit message (1st patch)
v6: https://lore.kernel.org/netdev/[email protected]/
- improve comments
- make the logic to load firmware more readable
- add Copy trait to reg::{C22 and C45}
- add Trevor Reviewed-by
v5: https://lore.kernel.org/netdev/[email protected]/
- fix the comments (3th patch)
- add RUST_FW_LOADER_ABSTRACTIONS dependency
- add Andrew and Benno Reviewed-by
v4: https://lore.kernel.org/netdev/[email protected]/
- fix the comments
- add Andrew's Reviewed-by
- fix the order of tags
- remove wrong endianness conversion
v3: https://lore.kernel.org/netdev/[email protected]/
- use addr_of_mut!` to avoid intermediate mutable reference
- update probe callback's Safety comment
- add MODULE_FIRMWARE equivalent
- add Alice's Reviewed-by
v2: https://lore.kernel.org/netdev/[email protected]/
- add comments in accordance with the hw datasheet
- unify C22 and C45 APIs
- load firmware in probe callback instead of config_init
- use firmware API
- handle firmware endian
- check firmware size
- use SZ_*K constants
- avoid confusing phy_id variable
v1: https://lore.kernel.org/netdev/[email protected]/
====================

rom: FUJITA Tomonori <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected]
Subject: [PATCH net-next v7 0/6] net: phy: add Applied Micro QT2025 PHY driver
Date: Sat, 24 Aug 2024 02:06:10 +0000	[thread overview]
Message-ID: <[email protected]> (raw)

This patchset adds a PHY driver for Applied Micro Circuits Corporation
QT2025.

The first patch adds Rust equivalent to include/linux/sizes.h, makes
code more readable. The 2-5th patches update the PHYLIB Rust bindings.
The 4th and 5th patches have been reviewed previously in a different
thread [1].

QT2025 PHY support was implemented as a part of an Ethernet driver for
Tehuti Networks TN40xx chips. Multiple vendors (DLink, Asus, Edimax,
QNAP, etc) developed adapters based on TN40xx chips. Tehuti Networks
went out of business and the driver wasn't merged into mainline. But
it's still distributed with some of the hardware (and also available
on some vendor sites).

The original driver handles multiple PHY hardware (AMCC QT2025, TI
TLK10232, Aqrate AQR105, and Marvell MV88X3120, MV88X3310, and
MV88E2010). I divided the original driver into MAC and PHY drivers and
implemented a QT2025 PHY driver in Rust.

The MAC driver for Tehuti Networks TN40xx chips was already merged in
6.11-rc1. The MAC and this PHY drivers have been tested with Edimax
EN-9320SFP+ 10G network adapter.

[1] https://lore.kernel.org/rust-for-linux/[email protected]/

v7:
- add Trevor as Reviewer to MAINTAINERS file entry
- add Trevor Reviewed-by
- add/fix comments
- replace uppercase hex with lowercase
- remove unnecessary code
- update the commit message (1st patch)
v6: https://lore.kernel.org/netdev/[email protected]/
- improve comments
- make the logic to load firmware more readable
- add Copy trait to reg::{C22 and C45}
- add Trevor Reviewed-by
v5: https://lore.kernel.org/netdev/[email protected]/
- fix the comments (3th patch)
- add RUST_FW_LOADER_ABSTRACTIONS dependency
- add Andrew and Benno Reviewed-by
v4: https://lore.kernel.org/netdev/[email protected]/
- fix the comments
- add Andrew's Reviewed-by
- fix the order of tags
- remove wrong endianness conversion
v3: https://lore.kernel.org/netdev/[email protected]/
- use addr_of_mut!` to avoid intermediate mutable reference
- update probe callback's Safety comment
- add MODULE_FIRMWARE equivalent
- add Alice's Reviewed-by
v2: https://lore.kernel.org/netdev/[email protected]/
- add comments in accordance with the hw datasheet
- unify C22 and C45 APIs
- load firmware in probe callback instead of config_init
- use firmware API
- handle firmware endian
- check firmware size
- use SZ_*K constants
- avoid confusing phy_id variable
v1: https://lore.kernel.org/netdev/[email protected]/
Signed-off-by: David S. Miller <[email protected]>

rom: FUJITA Tomonori <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected]
Subject: [PATCH net-next v7 0/6] net: phy: add Applied Micro QT2025 PHY driver
Date: Sat, 24 Aug 2024 02:06:10 +0000	[thread overview]
Message-ID: <[email protected]> (raw)

This patchset adds a PHY driver for Applied Micro Circuits Corporation
QT2025.

The first patch adds Rust equivalent to include/linux/sizes.h, makes
code more readable. The 2-5th patches update the PHYLIB Rust bindings.
The 4th and 5th patches have been reviewed previously in a different
thread [1].

QT2025 PHY support was implemented as a part of an Ethernet driver for
Tehuti Networks TN40xx chips. Multiple vendors (DLink, Asus, Edimax,
QNAP, etc) developed adapters based on TN40xx chips. Tehuti Networks
went out of business and the driver wasn't merged into mainline. But
it's still distributed with some of the hardware (and also available
on some vendor sites).

The original driver handles multiple PHY hardware (AMCC QT2025, TI
TLK10232, Aqrate AQR105, and Marvell MV88X3120, MV88X3310, and
MV88E2010). I divided the original driver into MAC and PHY drivers and
implemented a QT2025 PHY driver in Rust.

The MAC driver for Tehuti Networks TN40xx chips was already merged in
6.11-rc1. The MAC and this PHY drivers have been tested with Edimax
EN-9320SFP+ 10G network adapter.

[1] https://lore.kernel.org/rust-for-linux/[email protected]/

v7:
- add Trevor as Reviewer to MAINTAINERS file entry
- add Trevor Reviewed-by
- add/fix comments
- replace uppercase hex with lowercase
- remove unnecessary code
- update the commit message (1st patch)
v6: https://lore.kernel.org/netdev/[email protected]/
- improve comments
- make the logic to load firmware more readable
- add Copy trait to reg::{C22 and C45}
- add Trevor Reviewed-by
v5: https://lore.kernel.org/netdev/[email protected]/
- fix the comments (3th patch)
- add RUST_FW_LOADER_ABSTRACTIONS dependency
- add Andrew and Benno Reviewed-by
v4: https://lore.kernel.org/netdev/[email protected]/
- fix the comments
- add Andrew's Reviewed-by
- fix the order of tags
- remove wrong endianness conversion
v3: https://lore.kernel.org/netdev/[email protected]/
- use addr_of_mut!` to avoid intermediate mutable reference
- update probe callback's Safety comment
- add MODULE_FIRMWARE equivalent
- add Alice's Reviewed-by
v2: https://lore.kernel.org/netdev/[email protected]/
- add comments in accordance with the hw datasheet
- unify C22 and C45 APIs
- load firmware in probe callback instead of config_init
- use firmware API
- handle firmware endian
- check firmware size
- use SZ_*K constants
- avoid confusing phy_id variable
v1: https://lore.kernel.org/netdev/[email protected]/
Signed-off-by: David S. Miller <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>

4 files changed, 302 insertions, 39 deletions

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 274bdc1b0a82..58ed400198bf 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -43,6 +43,7 @@ pub mod net;
 pub mod page;
 pub mod prelude;
 pub mod print;
+pub mod sizes;
 mod static_assert;
 #[doc(hidden)]
 pub mod std_vendor;
diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index fd40b703d224..1d47884aa3cf 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -7,8 +7,9 @@
 //! C headers: [`include/linux/phy.h`](srctree/include/linux/phy.h).
 
 use crate::{error::*, prelude::*, types::Opaque};
+use core::{marker::PhantomData, ptr::addr_of_mut};
 
-use core::marker::PhantomData;
+pub mod reg;
 
 /// PHY state machine states.
 ///
@@ -58,8 +59,9 @@ pub enum DuplexMode {
 ///
 /// # 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.
+/// - 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.
+/// - This struct always has a valid `self.0.mdio.dev`.
 ///
 /// [`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
@@ -76,9 +78,11 @@ impl Device {
     ///
     /// # 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.
+    /// 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.
+    /// - `(*ptr).mdio.dev` must be a valid.
     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>();
@@ -175,32 +179,15 @@ impl Device {
         unsafe { (*phydev).duplex = v };
     }
 
-    /// Reads a given C22 PHY register.
+    /// Reads a 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)
-        }
+    pub fn read<R: reg::Register>(&mut self, reg: R) -> Result<u16> {
+        reg.read(self)
     }
 
-    /// 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)
-        })
+    /// Writes a PHY register.
+    pub fn write<R: reg::Register>(&mut self, reg: R, val: u16) -> Result {
+        reg.write(self, val)
     }
 
     /// Reads a paged register.
@@ -265,16 +252,8 @@ impl Device {
     }
 
     /// 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)
-        }
+    pub fn genphy_read_status<R: reg::Register>(&mut self) -> Result<u16> {
+        R::read_status(self)
     }
 
     /// Updates the link status.
@@ -302,6 +281,14 @@ impl Device {
     }
 }
 
+impl AsRef<kernel::device::Device> for Device {
+    fn as_ref(&self) -> &kernel::device::Device {
+        let phydev = self.0.get();
+        // SAFETY: The struct invariant ensures that `mdio.dev` is valid.
+        unsafe { kernel::device::Device::as_ref(addr_of_mut!((*phydev).mdio.dev)) }
+    }
+}
+
 /// Defines certain other features this PHY supports (like interrupts).
 ///
 /// These flag values are used in [`Driver::FLAGS`].
@@ -341,6 +328,21 @@ impl<T: Driver> Adapter<T> {
     /// # Safety
     ///
     /// `phydev` must be passed by the corresponding callback in `phy_driver`.
+    unsafe extern "C" fn probe_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
+        from_result(|| {
+            // SAFETY: This callback is called only in contexts
+            // where we can exclusively access `phy_device` because
+            // it's not published yet, so the accessors on `Device` are okay
+            // to call.
+            let dev = unsafe { Device::from_raw(phydev) };
+            T::probe(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 {
@@ -511,6 +513,11 @@ pub const fn create_phy_driver<T: Driver>() -> DriverVTable {
         } else {
             None
         },
+        probe: if T::HAS_PROBE {
+            Some(Adapter::<T>::probe_callback)
+        } else {
+            None
+        },
         get_features: if T::HAS_GET_FEATURES {
             Some(Adapter::<T>::get_features_callback)
         } else {
@@ -583,6 +590,11 @@ pub trait Driver {
         kernel::build_error(VTABLE_DEFAULT_ERROR)
     }
 
+    /// Sets up device-specific structures during discovery.
+    fn probe(_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)
diff --git a/rust/kernel/net/phy/reg.rs b/rust/kernel/net/phy/reg.rs
new file mode 100644
index 000000000000..a7db0064cb7d
--- /dev/null
+++ b/rust/kernel/net/phy/reg.rs
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 FUJITA Tomonori <[email protected]>
+
+//! PHY register interfaces.
+//!
+//! This module provides support for accessing PHY registers in the
+//! Ethernet management interface clauses 22 and 45 register namespaces, as
+//! defined in IEEE 802.3.
+
+use super::Device;
+use crate::build_assert;
+use crate::error::*;
+use crate::uapi;
+
+mod private {
+    /// Marker that a trait cannot be implemented outside of this crate
+    pub trait Sealed {}
+}
+
+/// Accesses PHY registers.
+///
+/// This trait is used to implement the unified interface to access
+/// C22 and C45 PHY registers.
+///
+/// # Examples
+///
+/// ```ignore
+/// fn link_change_notify(dev: &mut Device) {
+///     // read C22 BMCR register
+///     dev.read(C22::BMCR);
+///     // read C45 PMA/PMD control 1 register
+///     dev.read(C45::new(Mmd::PMAPMD, 0));
+///
+///     // Checks the link status as reported by registers in the C22 namespace
+///     // and updates current link state.
+///     dev.genphy_read_status::<phy::C22>();
+///     // Checks the link status as reported by registers in the C45 namespace
+///     // and updates current link state.
+///     dev.genphy_read_status::<phy::C45>();
+/// }
+/// ```
+pub trait Register: private::Sealed {
+    /// Reads a PHY register.
+    fn read(&self, dev: &mut Device) -> Result<u16>;
+
+    /// Writes a PHY register.
+    fn write(&self, dev: &mut Device, val: u16) -> Result;
+
+    /// Checks the link status and updates current link state.
+    fn read_status(dev: &mut Device) -> Result<u16>;
+}
+
+/// A single MDIO clause 22 register address (5 bits).
+#[derive(Copy, Clone, Debug)]
+pub struct C22(u8);
+
+impl C22 {
+    /// Basic mode control.
+    pub const BMCR: Self = C22(0x00);
+    /// Basic mode status.
+    pub const BMSR: Self = C22(0x01);
+    /// PHY identifier 1.
+    pub const PHYSID1: Self = C22(0x02);
+    /// PHY identifier 2.
+    pub const PHYSID2: Self = C22(0x03);
+    /// Auto-negotiation advertisement.
+    pub const ADVERTISE: Self = C22(0x04);
+    /// Auto-negotiation link partner base page ability.
+    pub const LPA: Self = C22(0x05);
+    /// Auto-negotiation expansion.
+    pub const EXPANSION: Self = C22(0x06);
+    /// Auto-negotiation next page transmit.
+    pub const NEXT_PAGE_TRANSMIT: Self = C22(0x07);
+    /// Auto-negotiation link partner received next page.
+    pub const LP_RECEIVED_NEXT_PAGE: Self = C22(0x08);
+    /// Master-slave control.
+    pub const MASTER_SLAVE_CONTROL: Self = C22(0x09);
+    /// Master-slave status.
+    pub const MASTER_SLAVE_STATUS: Self = C22(0x0a);
+    /// PSE Control.
+    pub const PSE_CONTROL: Self = C22(0x0b);
+    /// PSE Status.
+    pub const PSE_STATUS: Self = C22(0x0c);
+    /// MMD Register control.
+    pub const MMD_CONTROL: Self = C22(0x0d);
+    /// MMD Register address data.
+    pub const MMD_DATA: Self = C22(0x0e);
+    /// Extended status.
+    pub const EXTENDED_STATUS: Self = C22(0x0f);
+
+    /// Creates a new instance of `C22` with a vendor specific register.
+    pub const fn vendor_specific<const N: u8>() -> Self {
+        build_assert!(
+            N > 0x0f && N < 0x20,
+            "Vendor-specific register address must be between 16 and 31"
+        );
+        C22(N)
+    }
+}
+
+impl private::Sealed for C22 {}
+
+impl Register for C22 {
+    fn read(&self, dev: &mut Device) -> Result<u16> {
+        let phydev = dev.0.get();
+        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Device`.
+        // 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, self.0.into())
+        };
+        to_result(ret)?;
+        Ok(ret as u16)
+    }
+
+    fn write(&self, dev: &mut Device, val: u16) -> Result {
+        let phydev = dev.0.get();
+        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Device`.
+        // 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, self.0.into(), val)
+        })
+    }
+
+    fn read_status(dev: &mut Device) -> Result<u16> {
+        let phydev = dev.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) };
+        to_result(ret)?;
+        Ok(ret as u16)
+    }
+}
+
+/// A single MDIO clause 45 register device and address.
+#[derive(Copy, Clone, Debug)]
+pub struct Mmd(u8);
+
+impl Mmd {
+    /// Physical Medium Attachment/Dependent.
+    pub const PMAPMD: Self = Mmd(uapi::MDIO_MMD_PMAPMD as u8);
+    /// WAN interface sublayer.
+    pub const WIS: Self = Mmd(uapi::MDIO_MMD_WIS as u8);
+    /// Physical coding sublayer.
+    pub const PCS: Self = Mmd(uapi::MDIO_MMD_PCS as u8);
+    /// PHY Extender sublayer.
+    pub const PHYXS: Self = Mmd(uapi::MDIO_MMD_PHYXS as u8);
+    /// DTE Extender sublayer.
+    pub const DTEXS: Self = Mmd(uapi::MDIO_MMD_DTEXS as u8);
+    /// Transmission convergence.
+    pub const TC: Self = Mmd(uapi::MDIO_MMD_TC as u8);
+    /// Auto negotiation.
+    pub const AN: Self = Mmd(uapi::MDIO_MMD_AN as u8);
+    /// Separated PMA (1).
+    pub const SEPARATED_PMA1: Self = Mmd(8);
+    /// Separated PMA (2).
+    pub const SEPARATED_PMA2: Self = Mmd(9);
+    /// Separated PMA (3).
+    pub const SEPARATED_PMA3: Self = Mmd(10);
+    /// Separated PMA (4).
+    pub const SEPARATED_PMA4: Self = Mmd(11);
+    /// OFDM PMA/PMD.
+    pub const OFDM_PMAPMD: Self = Mmd(12);
+    /// Power unit.
+    pub const POWER_UNIT: Self = Mmd(13);
+    /// Clause 22 extension.
+    pub const C22_EXT: Self = Mmd(uapi::MDIO_MMD_C22EXT as u8);
+    /// Vendor specific 1.
+    pub const VEND1: Self = Mmd(uapi::MDIO_MMD_VEND1 as u8);
+    /// Vendor specific 2.
+    pub const VEND2: Self = Mmd(uapi::MDIO_MMD_VEND2 as u8);
+}
+
+/// A single MDIO clause 45 register device and address.
+///
+/// Clause 45 uses a 5-bit device address to access a specific MMD within
+/// a port, then a 16-bit register address to access a location within
+/// that device. `C45` represents this by storing a [`Mmd`] and
+/// a register number.
+pub struct C45 {
+    devad: Mmd,
+    regnum: u16,
+}
+
+impl C45 {
+    /// Creates a new instance of `C45`.
+    pub fn new(devad: Mmd, regnum: u16) -> Self {
+        Self { devad, regnum }
+    }
+}
+
+impl private::Sealed for C45 {}
+
+impl Register for C45 {
+    fn read(&self, dev: &mut Device) -> Result<u16> {
+        let phydev = dev.0.get();
+        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Device`.
+        // So it's just an FFI call.
+        let ret =
+            unsafe { bindings::phy_read_mmd(phydev, self.devad.0.into(), self.regnum.into()) };
+        to_result(ret)?;
+        Ok(ret as u16)
+    }
+
+    fn write(&self, dev: &mut Device, val: u16) -> Result {
+        let phydev = dev.0.get();
+        // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Device`.
+        // So it's just an FFI call.
+        to_result(unsafe {
+            bindings::phy_write_mmd(phydev, self.devad.0.into(), self.regnum.into(), val)
+        })
+    }
+
+    fn read_status(dev: &mut Device) -> Result<u16> {
+        let phydev = dev.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_c45_read_status(phydev) };
+        to_result(ret)?;
+        Ok(ret as u16)
+    }
+}
diff --git a/rust/kernel/sizes.rs b/rust/kernel/sizes.rs
new file mode 100644
index 000000000000..834c343e4170
--- /dev/null
+++ b/rust/kernel/sizes.rs
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Commonly used sizes.
+//!
+//! C headers: [`include/linux/sizes.h`](srctree/include/linux/sizes.h).
+
+/// 0x00000400
+pub const SZ_1K: usize = bindings::SZ_1K as usize;
+/// 0x00000800
+pub const SZ_2K: usize = bindings::SZ_2K as usize;
+/// 0x00001000
+pub const SZ_4K: usize = bindings::SZ_4K as usize;
+/// 0x00002000
+pub const SZ_8K: usize = bindings::SZ_8K as usize;
+/// 0x00004000
+pub const SZ_16K: usize = bindings::SZ_16K as usize;
+/// 0x00008000
+pub const SZ_32K: usize = bindings::SZ_32K as usize;
+/// 0x00010000
+pub const SZ_64K: usize = bindings::SZ_64K as usize;
+/// 0x00020000
+pub const SZ_128K: usize = bindings::SZ_128K as usize;
+/// 0x00040000
+pub const SZ_256K: usize = bindings::SZ_256K as usize;
+/// 0x00080000
+pub const SZ_512K: usize = bindings::SZ_512K as usize;