tn40xx — Tehuti Networks 10GbE Driver for FreeBSD 15

Kernel driver for Tehuti Networks TN40xx-based 10 Gigabit Ethernet adapters on FreeBSD 15.0-RELEASE.

Tehuti Networks ceased operations in January 2020. Their 10GbE adapters were sold under multiple brands and remain widely available on the used market. FreeBSD has never had in-tree support for these devices. This driver fills that gap.

Bold = tested. Others should work but are untested.

The TN9710P (MV88X3310) and TN9710Q (MV88E2010) are not supported — their PHY source files are not available.

The Marvell MV88X3120 PHY requires firmware that cannot be freely redistributed. A script extracts it from the AKiTiO macOS driver:

cd tools
./extract_firmware.sh

This downloads the AKiTiO driver package, extracts the firmware blob from the macOS kext binary, and generates sys/dev/tn40xx/MV88X3120_phy.h. SFP+ and CX4 adapters do not need this step.

cd sys/modules/tn40xx
make

If building out-of-tree (not from /usr/src):

make SRCTOP=/path/to/tn40xx-freebsd

kldload ./tn40xx.ko

Or copy to /boot/modules/ for persistent use:

cp tn40xx.ko /boot/modules/
echo 'tn40xx_load="YES"' >> /boot/loader.conf

ifconfig tn400 inet 192.168.1.1/24 up

This driver works with adapters connected via Thunderbolt enclosures (AKiTiO Thunder3, Sonnet Echo, etc.) on Mac hardware running FreeBSD. There are two caveats:

FreeBSD does not support Thunderbolt hot-plug. The adapter must be physically connected when the machine powers on, so the Thunderbolt controller enumerates the PCIe device during POST.

Intel Thunderbolt controllers (Falcon Ridge, Cactus Ridge) use an Internal Connection Manager (ICM) firmware that creates PCIe tunnels for config and memory-mapped I/O. However, the ICM does not configure the Thunderbolt switch fabric to forward MSI memory writes (address range 0xFEE00000) upstream to the CPU. MSI writes are silently dropped.

This driver includes a workaround: a dedicated kernel thread polls the device every 50 microseconds for RX/TX completion and link status changes. This provides functional networking without interrupts.

Tested between two MacBook Pros connected directly with a Cat6 cable, each with a TN9210 behind Thunderbolt:

With native MSI (non-Thunderbolt PCIe slot), the hardware should achieve close to 10 Gbps line rate.

The investigation ruled out all standard PCIe causes:

• PCI bridge memory windows do not claim the MSI address range
• Bus mastering is enabled on all bridges in the chain
• No ACS (Access Control Services) blocking
• No AER (Advanced Error Reporting) errors on the data path
• MSI address, vector, and target CPU are all correctly programmed

The Thunderbolt switch fabric silently drops the MSI writes. This is a firmware limitation of the ICM on Falcon Ridge and Cactus Ridge controllers. Fixing it would require implementing a software Thunderbolt connection manager to configure tunnel hop registers directly — effectively porting Linux's drivers/thunderbolt/ subsystem to FreeBSD.

FreeBSD's pci_alloc_msi() also programs an incorrect APIC destination ID for Thunderbolt-attached devices (targets wrong CPU), which is a separate kernel bug.

tn40.c                    FreeBSD attach/detach, ISR, poll thread, ifnet glue
tn40.h                    Driver private structures
tn40_hw.c                 Hardware abstraction: DMA, ring management, link state
tn40_hw.h                 Register definitions, PHY dispatch
tn40_mbuf.c               mbuf DMA mapping
tn40_fw.h                 Device firmware data

MV88X3120_phy.c           Marvell MV88X3120 PHY: firmware upload, link, speed
MV88X3120_phy_FreeBSD.c   FreeBSD ifmedia integration for MV88X3120
MV88X3120_phy.h           PHY firmware blob (generated, not in repo)

AQR105_phy.c              Aquantia AQR105 PHY driver
QT2025_phy.c              QT2025 SFP+ PHY driver
TLK10232_phy.c            TI TLK10232 SFP+ PHY driver
CX4.c                     CX4 PHY driver
*_FreeBSD.c               FreeBSD ifmedia wrappers for each PHY

This driver is based on scfcode/tn40xx, a community salvage of the original Tehuti Networks FreeBSD driver targeting FreeBSD 11/12. The MV88X3120 PHY code was ported from acooks/tn40xx-driver (Linux).

Changes from the scfcode base:

• Ported to FreeBSD 15 opaque if_t network interface API
• Added MV88X3120 PHY support (10GBase-T copper)
• Added polling thread for Thunderbolt MSI workaround
• Added INTx fallback when MSI allocation fails
• Fixed multicast for FreeBSD 13+ (if_foreach_lladdr)
• Fixed DRIVER_MODULE for FreeBSD 14+ (removed devclass_t)
• Replaced direct ifp->if_input() with if_input()

BSD 2-Clause. See LICENSE.