[PATCH net-next v2 0/6] net: phy: add Applied Micro QT2025 PHY driver

[PATCH net-next v2 0/6] net: phy: add Applied Micro QT2025 PHY driver

[FUJITA Tomonori]

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. Note that 4th and
5th patches are already reviewed by Trevor and Benno.

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.

v2:
- 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/all/20240415104701.4772-1-fujita.tomonori@gmail.com/

FUJITA Tomonori (6):
  rust: sizes: add commonly used constants
  rust: net::phy support probe callback
  rust: net::phy implement AsRef<kernel::device::Device> trait
  rust: net::phy unified read/write API for C22 and C45 registers
  rust: net::phy unified genphy_read_status function for C22 and C45
    registers
  net: phy: add Applied Micro QT2025 PHY driver

 MAINTAINERS                      |   8 ++
 drivers/net/phy/Kconfig          |   6 +
 drivers/net/phy/Makefile         |   1 +
 drivers/net/phy/ax88796b_rust.rs |   7 +-
 drivers/net/phy/qt2025.rs        |  92 +++++++++++++
 rust/kernel/lib.rs               |   1 +
 rust/kernel/net/phy.rs           |  77 ++++++-----
 rust/kernel/net/phy/reg.rs       | 219 +++++++++++++++++++++++++++++++
 rust/kernel/sizes.rs             |  26 ++++
 rust/uapi/uapi_helper.h          |   1 +
 10 files changed, 400 insertions(+), 38 deletions(-)
 create mode 100644 drivers/net/phy/qt2025.rs
 create mode 100644 rust/kernel/net/phy/reg.rs
 create mode 100644 rust/kernel/sizes.rs


base-commit: 0a658d088cc63745528cf0ec8a2c2df0f37742d9
-- 
2.34.1

[PATCH net-next v2 1/6] rust: sizes: add commonly used constants

[FUJITA Tomonori]

Add rust equivalent to include/linux/sizes.h, makes code more
readable. This adds only SZ_*K, which mostly used.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 rust/kernel/lib.rs   |  1 +
 rust/kernel/sizes.rs | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 rust/kernel/sizes.rs

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index e6b7d3a80bbc..ba2ba996678d 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -42,6 +42,7 @@
 pub mod net;
 pub mod prelude;
 pub mod print;
+pub mod sizes;
 mod static_assert;
 #[doc(hidden)]
 pub mod std_vendor;
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;
-- 
2.34.1

[PATCH net-next v2 2/6] rust: net::phy support probe callback

[FUJITA Tomonori]

Support phy_driver probe callback, used to set up device-specific
structures.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 rust/kernel/net/phy.rs | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index fd40b703d224..99a142348a34 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -338,6 +338,20 @@ 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 to `phy_device`, 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`.
@@ -511,6 +525,11 @@ 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 +602,11 @@ fn soft_reset(_dev: &mut Device) -> Result {
         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)
-- 
2.34.1

[PATCH net-next v2 3/6] rust: net::phy implement AsRef<kernel::device::Device> trait

[FUJITA Tomonori]

Implement AsRef<kernel::device::Device> trait for Device. A PHY driver
needs a reference to device::Device to call the firmware API.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 rust/kernel/net/phy.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 99a142348a34..561f0e357f31 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -302,6 +302,15 @@ pub fn genphy_read_abilities(&mut self) -> Result {
     }
 }
 
+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 we may access
+        // this field without additional synchronization.
+        unsafe { kernel::device::Device::as_ref(&mut (*phydev).mdio.dev) }
+    }
+}
+
 /// Defines certain other features this PHY supports (like interrupts).
 ///
 /// These flag values are used in [`Driver::FLAGS`].
-- 
2.34.1

[PATCH net-next v2 4/6] rust: net::phy unified read/write API for C22 and C45 registers

[FUJITA Tomonori]

Add the unified read/write API for C22 and C45 registers. The
abstractions support access to only C22 registers now. Instead of
adding read/write_c45 methods specifically for C45, a new reg module
supports the unified API to access C22 and C45 registers with trait,
by calling an appropriate phylib functions.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
---
 MAINTAINERS                      |   1 +
 drivers/net/phy/ax88796b_rust.rs |   7 +-
 rust/kernel/net/phy.rs           |  32 ++---
 rust/kernel/net/phy/reg.rs       | 193 +++++++++++++++++++++++++++++++
 rust/uapi/uapi_helper.h          |   1 +
 5 files changed, 206 insertions(+), 28 deletions(-)
 create mode 100644 rust/kernel/net/phy/reg.rs

diff --git a/MAINTAINERS b/MAINTAINERS
index c0a3d9e93689..2f85fad3b939 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8353,6 +8353,7 @@ L:	netdev@vger.kernel.org
 L:	rust-for-linux@vger.kernel.org
 S:	Maintained
 F:	rust/kernel/net/phy.rs
+F:	rust/kernel/net/phy/reg.rs
 
 EXEC & BINFMT API, ELF
 R:	Eric Biederman <ebiederm@xmission.com>
diff --git a/drivers/net/phy/ax88796b_rust.rs b/drivers/net/phy/ax88796b_rust.rs
index 5c92572962dc..8c7eb009d9fc 100644
--- a/drivers/net/phy/ax88796b_rust.rs
+++ b/drivers/net/phy/ax88796b_rust.rs
@@ -6,7 +6,7 @@
 //! C version of this driver: [`drivers/net/phy/ax88796b.c`](./ax88796b.c)
 use kernel::{
     c_str,
-    net::phy::{self, DeviceId, Driver},
+    net::phy::{self, reg::C22, DeviceId, Driver},
     prelude::*,
     uapi,
 };
@@ -24,7 +24,6 @@
     license: "GPL",
 }
 
-const MII_BMCR: u16 = uapi::MII_BMCR as u16;
 const BMCR_SPEED100: u16 = uapi::BMCR_SPEED100 as u16;
 const BMCR_FULLDPLX: u16 = uapi::BMCR_FULLDPLX as u16;
 
@@ -33,7 +32,7 @@
 // Toggle BMCR_RESET bit off to accommodate broken AX8796B PHY implementation
 // such as used on the Individual Computers' X-Surf 100 Zorro card.
 fn asix_soft_reset(dev: &mut phy::Device) -> Result {
-    dev.write(uapi::MII_BMCR as u16, 0)?;
+    dev.write(C22::BMCR, 0)?;
     dev.genphy_soft_reset()
 }
 
@@ -55,7 +54,7 @@ fn read_status(dev: &mut phy::Device) -> Result<u16> {
         }
         // If MII_LPA is 0, phy_resolve_aneg_linkmode() will fail to resolve
         // linkmode so use MII_BMCR as default values.
-        let ret = dev.read(MII_BMCR)?;
+        let ret = dev.read(C22::BMCR)?;
 
         if ret & BMCR_SPEED100 != 0 {
             dev.set_speed(uapi::SPEED_100);
diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 561f0e357f31..7ee06dd5a1b1 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -7,9 +7,10 @@
 //! C headers: [`include/linux/phy.h`](srctree/include/linux/phy.h).
 
 use crate::{error::*, prelude::*, types::Opaque};
-
 use core::marker::PhantomData;
 
+pub mod reg;
+
 /// PHY state machine states.
 ///
 /// Corresponds to the kernel's [`enum phy_state`].
@@ -175,32 +176,15 @@ pub fn set_duplex(&mut self, mode: DuplexMode) {
         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.
diff --git a/rust/kernel/net/phy/reg.rs b/rust/kernel/net/phy/reg.rs
new file mode 100644
index 000000000000..91f73179315e
--- /dev/null
+++ b/rust/kernel/net/phy/reg.rs
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 FUJITA Tomonori <fujita.tomonori@gmail.com>
+
+//! PHY register interfaces.
+//!
+//! This module provides support for accessing PHY registers via Ethernet
+//! management interface clause 22 and 45, 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));
+/// }
+/// ```
+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;
+}
+
+/// A single MDIO clause 22 register address (5 bits).
+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)
+        })
+    }
+}
+
+/// A single MDIO clause 45 register device and address.
+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)
+        })
+    }
+}
diff --git a/rust/uapi/uapi_helper.h b/rust/uapi/uapi_helper.h
index 08f5e9334c9e..76d3f103e764 100644
--- a/rust/uapi/uapi_helper.h
+++ b/rust/uapi/uapi_helper.h
@@ -7,5 +7,6 @@
  */
 
 #include <uapi/asm-generic/ioctl.h>
+#include <uapi/linux/mdio.h>
 #include <uapi/linux/mii.h>
 #include <uapi/linux/ethtool.h>
-- 
2.34.1

[PATCH net-next v2 5/6] rust: net::phy unified genphy_read_status function for C22 and C45 registers

[FUJITA Tomonori]

Add unified genphy_read_status function for C22 and C45
registers. Instead of having genphy_c22 and genphy_c45 methods, this
unifies genphy_read_status functions for C22 and C45.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
---
 rust/kernel/net/phy.rs     | 12 ++----------
 rust/kernel/net/phy/reg.rs | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 7ee06dd5a1b1..938820704aca 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -249,16 +249,8 @@ pub fn genphy_suspend(&mut self) -> Result {
     }
 
     /// 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.
diff --git a/rust/kernel/net/phy/reg.rs b/rust/kernel/net/phy/reg.rs
index 91f73179315e..4cf47335539b 100644
--- a/rust/kernel/net/phy/reg.rs
+++ b/rust/kernel/net/phy/reg.rs
@@ -30,6 +30,11 @@ pub trait Sealed {}
 ///     dev.read(C22::BMCR);
 ///     // read C45 PMA/PMD control 1 register
 ///     dev.read(C45::new(Mmd::PMAPMD, 0));
+///
+///     // Checks the link status and updates current link state via C22.
+///     dev.genphy_read_status::<phy::C22>();
+///     // Checks the link status and updates current link state via C45.
+///     dev.genphy_read_status::<phy::C45>();
 /// }
 /// ```
 pub trait Register: private::Sealed {
@@ -38,6 +43,9 @@ pub trait Register: private::Sealed {
 
     /// 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).
@@ -111,6 +119,15 @@ fn write(&self, dev: &mut Device, val: u16) -> Result {
             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.
@@ -190,4 +207,13 @@ fn write(&self, dev: &mut Device, val: u16) -> Result {
             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)
+    }
 }
-- 
2.34.1

[PATCH net-next v2 6/6] net: phy: add Applied Micro QT2025 PHY driver

[FUJITA Tomonori]

This driver supports Applied Micro Circuits Corporation QT2025 PHY,
based on a driver for Tehuti Networks TN40xx chips.

The original driver for TN40xx chips supports multiple PHY hardware
(AMCC QT2025, TI TLK10232, Aqrate AQR105, and Marvell 88X3120,
88X3310, and MV88E2010). This driver is extracted from the original
driver and modified to a PHY driver in Rust.

This has been tested with Edimax EN-9320SFP+ 10G network adapter.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 MAINTAINERS               |  7 +++
 drivers/net/phy/Kconfig   |  6 +++
 drivers/net/phy/Makefile  |  1 +
 drivers/net/phy/qt2025.rs | 92 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 106 insertions(+)
 create mode 100644 drivers/net/phy/qt2025.rs

diff --git a/MAINTAINERS b/MAINTAINERS
index 2f85fad3b939..b8fda7e0343c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1609,6 +1609,13 @@ F:	Documentation/admin-guide/perf/xgene-pmu.rst
 F:	Documentation/devicetree/bindings/perf/apm-xgene-pmu.txt
 F:	drivers/perf/xgene_pmu.c
 
+APPLIED MICRO QT2025 PHY DRIVER
+M:	FUJITA Tomonori <fujita.tomonori@gmail.com>
+L:	netdev@vger.kernel.org
+L:	rust-for-linux@vger.kernel.org
+S:	Maintained
+F:	drivers/net/phy/qt2025.rs
+
 APTINA CAMERA SENSOR PLL
 M:	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 7fddc8306d82..e0ff386d90cd 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -109,6 +109,12 @@ config ADIN1100_PHY
 	  Currently supports the:
 	  - ADIN1100 - Robust,Industrial, Low Power 10BASE-T1L Ethernet PHY
 
+config AMCC_QT2025_PHY
+	tristate "AMCC QT2025 PHY"
+	depends on RUST_PHYLIB_ABSTRACTIONS
+	help
+	  Adds support for the Applied Micro Circuits Corporation QT2025 PHY.
+
 source "drivers/net/phy/aquantia/Kconfig"
 
 config AX88796B_PHY
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 202ed7f450da..461d6a3b9997 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_ADIN_PHY)		+= adin.o
 obj-$(CONFIG_ADIN1100_PHY)	+= adin1100.o
 obj-$(CONFIG_AIR_EN8811H_PHY)   += air_en8811h.o
 obj-$(CONFIG_AMD_PHY)		+= amd.o
+obj-$(CONFIG_AMCC_QT2025_PHY)	+= qt2025.o
 obj-$(CONFIG_AQUANTIA_PHY)	+= aquantia/
 ifdef CONFIG_AX88796B_RUST_PHY
   obj-$(CONFIG_AX88796B_PHY)	+= ax88796b_rust.o
diff --git a/drivers/net/phy/qt2025.rs b/drivers/net/phy/qt2025.rs
new file mode 100644
index 000000000000..b93472865bde
--- /dev/null
+++ b/drivers/net/phy/qt2025.rs
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) Tehuti Networks Ltd.
+// Copyright (C) 2024 FUJITA Tomonori <fujita.tomonori@gmail.com>
+
+//! Applied Micro Circuits Corporation QT2025 PHY driver
+use kernel::c_str;
+use kernel::error::code;
+use kernel::firmware::Firmware;
+use kernel::net::phy::{
+    self,
+    reg::{Mmd, C45},
+    DeviceId, Driver,
+};
+use kernel::prelude::*;
+use kernel::sizes::{SZ_16K, SZ_32K, SZ_8K};
+
+kernel::module_phy_driver! {
+    drivers: [PhyQT2025],
+    device_table: [
+        DeviceId::new_with_driver::<PhyQT2025>(),
+    ],
+    name: "qt2025_phy",
+    author: "FUJITA Tomonori <fujita.tomonori@gmail.com>",
+    description: "AMCC QT2025 PHY driver",
+    license: "GPL",
+}
+
+struct PhyQT2025;
+
+#[vtable]
+impl Driver for PhyQT2025 {
+    const NAME: &'static CStr = c_str!("QT2025 10Gpbs SFP+");
+    const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x0043A400);
+
+    fn probe(dev: &mut phy::Device) -> Result<()> {
+        // The hardware is configurable?
+        let hw_id = dev.read(C45::new(Mmd::PMAPMD, 0xd001))?;
+        if (hw_id >> 8) & 0xff != 0xb3 {
+            return Ok(());
+        }
+
+        // The 8051 will remain in the reset state.
+        dev.write(C45::new(Mmd::PMAPMD, 0xC300), 0x0000)?;
+        // Configure the 8051 clock frequency.
+        dev.write(C45::new(Mmd::PMAPMD, 0xC302), 0x0004)?;
+        // Non loopback mode.
+        dev.write(C45::new(Mmd::PMAPMD, 0xC319), 0x0038)?;
+        // Global control bit to select between LAN and WAN (WIS) mode.
+        dev.write(C45::new(Mmd::PMAPMD, 0xC31A), 0x0098)?;
+        dev.write(C45::new(Mmd::PCS, 0x0026), 0x0E00)?;
+        dev.write(C45::new(Mmd::PCS, 0x0027), 0x0893)?;
+        dev.write(C45::new(Mmd::PCS, 0x0028), 0xA528)?;
+        dev.write(C45::new(Mmd::PCS, 0x0029), 0x0003)?;
+        // Configure transmit and recovered clock.
+        dev.write(C45::new(Mmd::PMAPMD, 0xC30A), 0x06E1)?;
+        // The 8051 will finish the reset state.
+        dev.write(C45::new(Mmd::PMAPMD, 0xC300), 0x0002)?;
+        // The 8051 will start running from the boot ROM.
+        dev.write(C45::new(Mmd::PCS, 0xE854), 0x00C0)?;
+
+        let fw = Firmware::request(c_str!("qt2025-2.0.3.3.fw"), dev.as_ref())?;
+        if fw.data().len() > SZ_16K + SZ_8K {
+            return Err(code::EFBIG);
+        }
+
+        // The 24kB of program memory space is accessible by MDIO.
+        // The first 16kB of memory is located in the address range 3.8000h - 3.BFFFh.
+        // The next 8kB of memory is located at 4.8000h - 4.9FFFh.
+        let mut j = SZ_32K;
+        for (i, val) in fw.data().iter().enumerate() {
+            if i == SZ_16K {
+                j = SZ_32K;
+            }
+
+            let mmd = if i < SZ_16K { Mmd::PCS } else { Mmd::PHYXS };
+            dev.write(
+                C45::new(mmd, j as u16),
+                <u8 as Into<u16>>::into(*val).to_le(),
+            )?;
+
+            j += 1;
+        }
+        // The 8051 will start running from SRAM.
+        dev.write(C45::new(Mmd::PCS, 0xE854), 0x0040)?;
+
+        Ok(())
+    }
+
+    fn read_status(dev: &mut phy::Device) -> Result<u16> {
+        dev.genphy_read_status::<C45>()
+    }
+}
-- 
2.34.1

Re: [PATCH net-next v2 1/6] rust: sizes: add commonly used constants

[Alice Ryhl]

On Wed, Jul 31, 2024 at 6:22 AM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Add rust equivalent to include/linux/sizes.h, makes code more
> readable. This adds only SZ_*K, which mostly used.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[Alice Ryhl]

On Wed, Jul 31, 2024 at 6:22 AM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Support phy_driver probe callback, used to set up device-specific
> structures.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH net-next v2 3/6] rust: net::phy implement AsRef<kernel::device::Device> trait

[Alice Ryhl]

On Wed, Jul 31, 2024 at 6:22 AM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Implement AsRef<kernel::device::Device> trait for Device. A PHY driver
> needs a reference to device::Device to call the firmware API.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> ---
>  rust/kernel/net/phy.rs | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
> index 99a142348a34..561f0e357f31 100644
> --- a/rust/kernel/net/phy.rs
> +++ b/rust/kernel/net/phy.rs
> @@ -302,6 +302,15 @@ pub fn genphy_read_abilities(&mut self) -> Result {
>      }
>  }
>
> +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 we may access
> +        // this field without additional synchronization.
> +        unsafe { kernel::device::Device::as_ref(&mut (*phydev).mdio.dev) }

This is a case where I would recommend use of the `addr_of_mut!`
macro. The type of the mutable reference will be `&mut
bindings::device` without a `Opaque` wrapper around the referent, and
the lack of `Opaque` raises questions about uniqueness guarantees.
Using `addr_of_mut!` sidesteps those questions.

With `addr_of_mut!` and no intermediate mutable reference you may add:

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Alice

Re: [PATCH net-next v2 1/6] rust: sizes: add commonly used constants

[Andrew Lunn]

On Wed, Jul 31, 2024 at 01:21:31PM +0900, FUJITA Tomonori wrote:
> Add rust equivalent to include/linux/sizes.h, makes code more
> readable. This adds only SZ_*K, which mostly used.
> 
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> ---
>  rust/kernel/lib.rs   |  1 +
>  rust/kernel/sizes.rs | 26 ++++++++++++++++++++++++++
>  2 files changed, 27 insertions(+)
>  create mode 100644 rust/kernel/sizes.rs
> 
> diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
> index e6b7d3a80bbc..ba2ba996678d 100644
> --- a/rust/kernel/lib.rs
> +++ b/rust/kernel/lib.rs
> @@ -42,6 +42,7 @@
>  pub mod net;
>  pub mod prelude;
>  pub mod print;
> +pub mod sizes;
>  mod static_assert;
>  #[doc(hidden)]
>  pub mod std_vendor;
> 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;

1K is 1K, independent of it being C 1K or Rust 1K. In this case, does
it makes sense to actually use the C header? I don't know? But the
Rust people seems to think this is O.K.

   Andrew

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[Andrew Lunn]

On Wed, Jul 31, 2024 at 01:21:32PM +0900, FUJITA Tomonori wrote:
> Support phy_driver probe callback, used to set up device-specific
> structures.
> 
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> ---
>  rust/kernel/net/phy.rs | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
> index fd40b703d224..99a142348a34 100644
> --- a/rust/kernel/net/phy.rs
> +++ b/rust/kernel/net/phy.rs
> @@ -338,6 +338,20 @@ 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 to `phy_device`, so the accessors on
> +            // `Device` are okay to call.

This one is slightly different to other callbacks. probe is called
without the mutex. Instead, probe is called before the device is
published. So the comment is correct, but given how important Rust
people take these SAFETY comments, maybe it should indicate it is
different to others?

	Andrew

Re: [PATCH net-next v2 1/6] rust: sizes: add commonly used constants

[Alice Ryhl]

On Wed, Jul 31, 2024 at 2:17 PM Andrew Lunn <andrew@lunn.ch> wrote:
>
> On Wed, Jul 31, 2024 at 01:21:31PM +0900, FUJITA Tomonori wrote:
> > Add rust equivalent to include/linux/sizes.h, makes code more
> > readable. This adds only SZ_*K, which mostly used.
> >
> > Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> > ---
> >  rust/kernel/lib.rs   |  1 +
> >  rust/kernel/sizes.rs | 26 ++++++++++++++++++++++++++
> >  2 files changed, 27 insertions(+)
> >  create mode 100644 rust/kernel/sizes.rs
> >
> > diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
> > index e6b7d3a80bbc..ba2ba996678d 100644
> > --- a/rust/kernel/lib.rs
> > +++ b/rust/kernel/lib.rs
> > @@ -42,6 +42,7 @@
> >  pub mod net;
> >  pub mod prelude;
> >  pub mod print;
> > +pub mod sizes;
> >  mod static_assert;
> >  #[doc(hidden)]
> >  pub mod std_vendor;
> > 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;
>
> 1K is 1K, independent of it being C 1K or Rust 1K. In this case, does
> it makes sense to actually use the C header? I don't know? But the
> Rust people seems to think this is O.K.

Shrug. I don't think it really matters.

If using the C header required adding constants in
rust/bindings/bindings_helper.h to actually make the constants usable
from Rust, then I would say we should just set the constants from the
Rust side. But in this case using the C header just works so I don't
think it's an issue.

Alice

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[Alice Ryhl]

On Wed, Jul 31, 2024 at 2:24 PM Andrew Lunn <andrew@lunn.ch> wrote:
>
> On Wed, Jul 31, 2024 at 01:21:32PM +0900, FUJITA Tomonori wrote:
> > Support phy_driver probe callback, used to set up device-specific
> > structures.
> >
> > Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> > ---
> >  rust/kernel/net/phy.rs | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >
> > diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
> > index fd40b703d224..99a142348a34 100644
> > --- a/rust/kernel/net/phy.rs
> > +++ b/rust/kernel/net/phy.rs
> > @@ -338,6 +338,20 @@ 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 to `phy_device`, so the accessors on
> > +            // `Device` are okay to call.
>
> This one is slightly different to other callbacks. probe is called
> without the mutex. Instead, probe is called before the device is
> published. So the comment is correct, but given how important Rust
> people take these SAFETY comments, maybe it should indicate it is
> different to others?

Interesting. Given that we don't hold the mutex, does that mean that
some of the methods on Device are not safe to call in this context? Or
is there something else that makes it okay to call them despite not
holding the mutex?

Alice

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[Andrew Lunn]

> > > +    /// `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 to `phy_device`, so the accessors on
> > > +            // `Device` are okay to call.
> >
> > This one is slightly different to other callbacks. probe is called
> > without the mutex. Instead, probe is called before the device is
> > published. So the comment is correct, but given how important Rust
> > people take these SAFETY comments, maybe it should indicate it is
> > different to others?
> 
> Interesting. Given that we don't hold the mutex, does that mean that
> some of the methods on Device are not safe to call in this context? Or
> is there something else that makes it okay to call them despite not
> holding the mutex?

probe is always the first method called on a device driver to match it
to a device. Traditionally, if probe fails, the device is destroyed,
since there is no driver to drive it. probe needs to complete
successfully before the phy_device structure is published so a MAC
driver can reference it. If it is not published, nothing can have
access to it, so you don't need to worry about parallel activities on
it.

And a PHY driver does not need a probe function. Historically, probe
was all about, can this driver drive this hardware. However, since we
have ID registers in the hardware, we already know the driver can
drive the hardware. So probe is now about setting up whatever needs
setting up. For PHY drivers, there is often nothing, no local state
needed, etc. So the probe is optional.

	Andrew

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[FUJITA Tomonori]

Thanks for the review!

On Wed, 31 Jul 2024 14:32:18 +0200
Alice Ryhl <aliceryhl@google.com> wrote:

>> > +    /// # 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 to `phy_device`, so the accessors on
>> > +            // `Device` are okay to call.
>>
>> This one is slightly different to other callbacks. probe is called
>> without the mutex. Instead, probe is called before the device is
>> published. So the comment is correct, but given how important Rust
>> people take these SAFETY comments, maybe it should indicate it is
>> different to others?
> 
> Interesting. Given that we don't hold the mutex, does that mean that
> some of the methods on Device are not safe to call in this context? Or
> is there something else that makes it okay to call them despite not
> holding the mutex?

Before the callback, the device object was initialized properly by
PHYLIB and no concurrent access so all the methods can be called
safely (no kernel panic), I think.

If the safety comment needs to updated, how about the following?

SAFETY: This callback is called only in contexts where we can
exclusively access to `phy_device` because it's not published yet, so
the accessors on `Device` are okay to call.

Re: [PATCH net-next v2 3/6] rust: net::phy implement AsRef<kernel::device::Device> trait

[FUJITA Tomonori]

On Wed, 31 Jul 2024 10:38:11 +0200
Alice Ryhl <aliceryhl@google.com> wrote:

>> +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 we may access
>> +        // this field without additional synchronization.
>> +        unsafe { kernel::device::Device::as_ref(&mut (*phydev).mdio.dev) }
> 
> This is a case where I would recommend use of the `addr_of_mut!`
> macro. The type of the mutable reference will be `&mut
> bindings::device` without a `Opaque` wrapper around the referent, and
> the lack of `Opaque` raises questions about uniqueness guarantees.
> Using `addr_of_mut!` sidesteps those questions.
> 
> With `addr_of_mut!` and no intermediate mutable reference you may add:
> 
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Understood. I will use addr_of_mut! in v3.

Thanks a lot!

Re: [PATCH net-next v2 1/6] rust: sizes: add commonly used constants

[FUJITA Tomonori]

On Wed, 31 Jul 2024 14:30:23 +0200
Alice Ryhl <aliceryhl@google.com> wrote:

>> > +//! 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;
>>
>> 1K is 1K, independent of it being C 1K or Rust 1K. In this case, does
>> it makes sense to actually use the C header? I don't know? But the
>> Rust people seems to think this is O.K.
> 
> Shrug. I don't think it really matters.
> 
> If using the C header required adding constants in
> rust/bindings/bindings_helper.h to actually make the constants usable
> from Rust, then I would say we should just set the constants from the
> Rust side. But in this case using the C header just works so I don't
> think it's an issue.

Either is fine by me. I'll keep the current version if nobody has
strong preference.

Thanks for the quick review!

Re: [PATCH net-next v2 6/6] net: phy: add Applied Micro QT2025 PHY driver

[FUJITA Tomonori]

Hi Trevor,

On Wed, 31 Jul 2024 13:21:36 +0900
FUJITA Tomonori <fujita.tomonori@gmail.com> wrote:

> +impl Driver for PhyQT2025 {
> +    const NAME: &'static CStr = c_str!("QT2025 10Gpbs SFP+");
> +    const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x0043A400);
> +
> +    fn probe(dev: &mut phy::Device) -> Result<()> {
> +        // The hardware is configurable?
> +        let hw_id = dev.read(C45::new(Mmd::PMAPMD, 0xd001))?;
> +        if (hw_id >> 8) & 0xff != 0xb3 {
> +            return Ok(());
> +        }
> +
> +        // The 8051 will remain in the reset state.
> +        dev.write(C45::new(Mmd::PMAPMD, 0xC300), 0x0000)?;
> +        // Configure the 8051 clock frequency.
> +        dev.write(C45::new(Mmd::PMAPMD, 0xC302), 0x0004)?;
> +        // Non loopback mode.
> +        dev.write(C45::new(Mmd::PMAPMD, 0xC319), 0x0038)?;
> +        // Global control bit to select between LAN and WAN (WIS) mode.
> +        dev.write(C45::new(Mmd::PMAPMD, 0xC31A), 0x0098)?;
> +        dev.write(C45::new(Mmd::PCS, 0x0026), 0x0E00)?;
> +        dev.write(C45::new(Mmd::PCS, 0x0027), 0x0893)?;
> +        dev.write(C45::new(Mmd::PCS, 0x0028), 0xA528)?;
> +        dev.write(C45::new(Mmd::PCS, 0x0029), 0x0003)?;
> +        // Configure transmit and recovered clock.
> +        dev.write(C45::new(Mmd::PMAPMD, 0xC30A), 0x06E1)?;
> +        // The 8051 will finish the reset state.
> +        dev.write(C45::new(Mmd::PMAPMD, 0xC300), 0x0002)?;
> +        // The 8051 will start running from the boot ROM.
> +        dev.write(C45::new(Mmd::PCS, 0xE854), 0x00C0)?;

You said that it might be nicer to put the above in a table
previously, I think. The following looks nicer? If so, I will use the
table in v3.


diff --git a/drivers/net/phy/qt2025.rs b/drivers/net/phy/qt2025.rs
index b93472865bde..1b89495d7017 100644
--- a/drivers/net/phy/qt2025.rs
+++ b/drivers/net/phy/qt2025.rs
@@ -27,6 +27,27 @@
 
 struct PhyQT2025;
 
+const QT2025_INIT_ROUTINE: &[(C45, u16)] = &[
+    // The 8051 will remain in the reset state.
+    (C45::new(Mmd::PMAPMD, 0xC300), 0x0000),
+    // Configure the 8051 clock frequency.
+    (C45::new(Mmd::PMAPMD, 0xC302), 0x0004),
+    // Non loopback mode.
+    (C45::new(Mmd::PMAPMD, 0xC319), 0x0038),
+    // Global control bit to select between LAN and WAN (WIS) mode.
+    (C45::new(Mmd::PMAPMD, 0xC31A), 0x0098),
+    (C45::new(Mmd::PCS, 0x0026), 0x0E00),
+    (C45::new(Mmd::PCS, 0x0027), 0x0893),
+    (C45::new(Mmd::PCS, 0x0028), 0xA528),
+    (C45::new(Mmd::PCS, 0x0029), 0x0003),
+    // Configure transmit and recovered clock.
+    (C45::new(Mmd::PMAPMD, 0xC30A), 0x06E1),
+    // The 8051 will finish the reset state.
+    (C45::new(Mmd::PMAPMD, 0xC300), 0x0002),
+    // The 8051 will start running from the boot ROM.
+    (C45::new(Mmd::PCS, 0xE854), 0x00C0),
+];
+
 #[vtable]
 impl Driver for PhyQT2025 {
     const NAME: &'static CStr = c_str!("QT2025 10Gpbs SFP+");
@@ -39,24 +60,9 @@ fn probe(dev: &mut phy::Device) -> Result<()> {
             return Ok(());
         }
 
-        // The 8051 will remain in the reset state.
-        dev.write(C45::new(Mmd::PMAPMD, 0xC300), 0x0000)?;
-        // Configure the 8051 clock frequency.
-        dev.write(C45::new(Mmd::PMAPMD, 0xC302), 0x0004)?;
-        // Non loopback mode.
-        dev.write(C45::new(Mmd::PMAPMD, 0xC319), 0x0038)?;
-        // Global control bit to select between LAN and WAN (WIS) mode.
-        dev.write(C45::new(Mmd::PMAPMD, 0xC31A), 0x0098)?;
-        dev.write(C45::new(Mmd::PCS, 0x0026), 0x0E00)?;
-        dev.write(C45::new(Mmd::PCS, 0x0027), 0x0893)?;
-        dev.write(C45::new(Mmd::PCS, 0x0028), 0xA528)?;
-        dev.write(C45::new(Mmd::PCS, 0x0029), 0x0003)?;
-        // Configure transmit and recovered clock.
-        dev.write(C45::new(Mmd::PMAPMD, 0xC30A), 0x06E1)?;
-        // The 8051 will finish the reset state.
-        dev.write(C45::new(Mmd::PMAPMD, 0xC300), 0x0002)?;
-        // The 8051 will start running from the boot ROM.
-        dev.write(C45::new(Mmd::PCS, 0xE854), 0x00C0)?;
+        for (reg, val) in QT2025_INIT_ROUTINE {
+            dev.write(*reg, *val)?;
+        }
 
         let fw = Firmware::request(c_str!("qt2025-2.0.3.3.fw"), dev.as_ref())?;
         if fw.data().len() > SZ_16K + SZ_8K {
diff --git a/rust/kernel/net/phy/reg.rs b/rust/kernel/net/phy/reg.rs
index 4cf47335539b..603adfd369c1 100644
--- a/rust/kernel/net/phy/reg.rs
+++ b/rust/kernel/net/phy/reg.rs
@@ -49,6 +49,7 @@ pub trait Register: private::Sealed {
 }
 
 /// A single MDIO clause 22 register address (5 bits).
+#[derive(Clone, Copy)]
 pub struct C22(u8);
 
 impl C22 {
@@ -131,6 +132,7 @@ fn read_status(dev: &mut Device) -> Result<u16> {
 }
 
 /// A single MDIO clause 45 register device and address.
+#[derive(Clone, Copy)]
 pub struct Mmd(u8);
 
 impl Mmd {
@@ -174,6 +176,7 @@ impl Mmd {
 /// 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.
+#[derive(Clone, Copy)]
 pub struct C45 {
     devad: Mmd,
     regnum: u16,
@@ -181,7 +184,7 @@ pub struct C45 {
 
 impl C45 {
     /// Creates a new instance of `C45`.
-    pub fn new(devad: Mmd, regnum: u16) -> Self {
+    pub const fn new(devad: Mmd, regnum: u16) -> Self {
         Self { devad, regnum }
     }
 }

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[Alice Ryhl]

On Thu, Aug 1, 2024 at 2:17 AM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Thanks for the review!
>
> On Wed, 31 Jul 2024 14:32:18 +0200
> Alice Ryhl <aliceryhl@google.com> wrote:
>
> >> > +    /// # 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 to `phy_device`, so the accessors on
> >> > +            // `Device` are okay to call.
> >>
> >> This one is slightly different to other callbacks. probe is called
> >> without the mutex. Instead, probe is called before the device is
> >> published. So the comment is correct, but given how important Rust
> >> people take these SAFETY comments, maybe it should indicate it is
> >> different to others?
> >
> > Interesting. Given that we don't hold the mutex, does that mean that
> > some of the methods on Device are not safe to call in this context? Or
> > is there something else that makes it okay to call them despite not
> > holding the mutex?
>
> Before the callback, the device object was initialized properly by
> PHYLIB and no concurrent access so all the methods can be called
> safely (no kernel panic), I think.
>
> If the safety comment needs to updated, how about the following?
>
> SAFETY: This callback is called only in contexts where we can
> exclusively access to `phy_device` because it's not published yet, so
> the accessors on `Device` are okay to call.

Yes, that sounds good to me. With the updated safety comment, feel
free to include my Reviewed-by in your next version.

Alice

Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

[Alice Ryhl]

On Wed, Jul 31, 2024 at 10:57 PM Andrew Lunn <andrew@lunn.ch> wrote:
>
> > > > +    /// `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 to `phy_device`, so the accessors on
> > > > +            // `Device` are okay to call.
> > >
> > > This one is slightly different to other callbacks. probe is called
> > > without the mutex. Instead, probe is called before the device is
> > > published. So the comment is correct, but given how important Rust
> > > people take these SAFETY comments, maybe it should indicate it is
> > > different to others?
> >
> > Interesting. Given that we don't hold the mutex, does that mean that
> > some of the methods on Device are not safe to call in this context? Or
> > is there something else that makes it okay to call them despite not
> > holding the mutex?
>
> probe is always the first method called on a device driver to match it
> to a device. Traditionally, if probe fails, the device is destroyed,
> since there is no driver to drive it. probe needs to complete
> successfully before the phy_device structure is published so a MAC
> driver can reference it. If it is not published, nothing can have
> access to it, so you don't need to worry about parallel activities on
> it.
>
> And a PHY driver does not need a probe function. Historically, probe
> was all about, can this driver drive this hardware. However, since we
> have ID registers in the hardware, we already know the driver can
> drive the hardware. So probe is now about setting up whatever needs
> setting up. For PHY drivers, there is often nothing, no local state
> needed, etc. So the probe is optional.

Makes sense. Thanks for the explanation!

Alice