net: phy: add Applied Micro QT2025 PHY driver

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.
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -1609,6 +1609,14 @@ 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>
+R:	Trevor Gross <tmgross@umich.edu>
+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

drivers/net/phy/Kconfig

@@ -112,6 +112,13 @@ 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
+	depends on RUST_FW_LOADER_ABSTRACTIONS
+	help
+	  Adds support for the Applied Micro Circuits Corporation QT2025 PHY.
+
 source "drivers/net/phy/aquantia/Kconfig"
 
 config AX88796B_PHY

drivers/net/phy/Makefile

@@ -37,6 +37,7 @@ 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

drivers/net/phy/qt2025.rs

+// 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
+//!
+//! This driver is based on the vendor driver `QT2025_phy.c`. This source
+//! and firmware can be downloaded on the EN-9320SFP+ support site.
+//!
+//! The QT2025 PHY integrates an Intel 8051 micro-controller.
+
+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_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",
+    firmware: ["qt2025-2.0.3.3.fw"],
+}
+
+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<()> {
+        // Check the hardware revision code.
+        // Only 0x3b works with this driver and firmware.
+        let hw_rev = dev.read(C45::new(Mmd::PMAPMD, 0xd001))?;
+        if (hw_rev >> 8) != 0xb3 {
+            return Err(code::ENODEV);
+        }
+
+        // `MICRO_RESETN`: hold the micro-controller in reset while configuring.
+        dev.write(C45::new(Mmd::PMAPMD, 0xc300), 0x0000)?;
+        // `SREFCLK_FREQ`: configure clock frequency of the micro-controller.
+        dev.write(C45::new(Mmd::PMAPMD, 0xc302), 0x0004)?;
+        // Non loopback mode.
+        dev.write(C45::new(Mmd::PMAPMD, 0xc319), 0x0038)?;
+        // `CUS_LAN_WAN_CONFIG`: select between LAN and WAN (WIS) mode.
+        dev.write(C45::new(Mmd::PMAPMD, 0xc31a), 0x0098)?;
+        // The following writes use standardized registers (3.38 through
+        // 3.41 5/10/25GBASE-R PCS test pattern seed B) for something else.
+        // We don't know what.
+        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, 0xa30a), 0x06e1)?;
+        // `MICRO_RESETN`: release the micro-controller from the reset state.
+        dev.write(C45::new(Mmd::PMAPMD, 0xc300), 0x0002)?;
+        // The micro-controller 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 dst_offset = 0;
+        let mut dst_mmd = Mmd::PCS;
+        for (src_idx, val) in fw.data().iter().enumerate() {
+            if src_idx == SZ_16K {
+                // Start writing to the next register with no offset
+                dst_offset = 0;
+                dst_mmd = Mmd::PHYXS;
+            }
+
+            dev.write(C45::new(dst_mmd, 0x8000 + dst_offset), (*val).into())?;
+
+            dst_offset += 1;
+        }
+        // The micro-controller will start running from SRAM.
+        dev.write(C45::new(Mmd::PCS, 0xe854), 0x0040)?;
+
+        // TODO: sleep here until the hw becomes ready.
+        Ok(())
+    }
+
+    fn read_status(dev: &mut phy::Device) -> Result<u16> {
+        dev.genphy_read_status::<C45>()
+    }
+}