tik-stbuehler/axxon-ox16pci954-flash

Axxon RS232 OX16PCI954 flash tool

Axxon RS232 OX16PCI954 flash tool

Use at your own risk!

Coded for the following PCIe devices:

• https://axxon.io/lf781kb_pcie_8s_rs232_adapter/
• https://axxon.io/lf729kb_16s_rs232_pcie_adapter_card/

They identify as a "PCI Express-to-PCI Bridge" ("PEX 8112") and two or four instances of a "OX16PCI954" PCI device (each providing four UART interfaces).

Why

On some cards not all "OX16PCI954" are properly flashed, which might result in output like this:

$ lspci
65:00.0 PCI bridge: PLX Technology, Inc. PEX8112 x1 Lane PCI Express-to-PCI Bridge (rev aa)
66:00.0 Serial controller: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 0 (Uart)
66:00.1 Bridge: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 0 (Disabled)
66:01.0 Serial controller: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 0 (Uart)
66:01.1 Bridge: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 1 (8bit bus)
66:02.0 Serial controller: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 0 (Uart)
66:02.1 Bridge: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 1 (8bit bus)
66:03.0 Serial controller: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 0 (Uart)
66:03.1 Bridge: Oxford Semiconductor Ltd OX16PCI954 (Quad 16950 UART) function 1 (8bit bus)

Notice how all but the first "slot" have a second function with "8bit bus" - and linux even tries to use them as 4xUART with the "serial" driver...

Running

You'll need cargo from rust to build the tool.

To build (if outdated / not compiled yet) and run:

cargo run --bin axxon-ox16pci954-flash

To pass options to the program, insert -- before them:

cargo run --bin axxon-ox16pci954-flash -- --help

To actually flash the contained images (instead of just checking them) use:

cargo run --bin axxon-ox16pci954-flash -- --flash

Before flashing the tool makes sure that the "PEX 8112" bridge contains axxon in the image at the required place, and that "OX16PCI954" devices are on a bus behind such bridges.

Hardware

OX16PCI954

The chip supports various modes via two functions, which could be configured via two pins (although there isn't a "good" way to only enable 4x UART on function 0 and disable function 1).

Only function 0 (4x UART) is of interest, function 1 is not wired.

Uses an (optional, but present on the Axxon cards) external EEPROM for configuration; the EEPROM data is a word (16-bit) stream.

The flashing tool from the vendor disables function 1 by writing 0x00 to the lower 8-bit of the device id, effectively making it 1415:9500 (which is the official ID for "disabled function 0", not "disabled function 1", which would be 1415:9510).

PEX 8112

This is the PCIe-to-PCI bridge, and identifies as a device with a single function (PCI id 10b5:8112).

Documentation ("Data Book") was available from: https://www.broadcom.com/products/pcie-switches-bridges/pcie-bridges/pex8112#documentation

Uses an (optional, but present on the Axxon cards) external EEPROM for configuration; the EEPROM data is a byte stream. At offset 0x78 (120) the data should contain the string axxon (although the PCI device won't care about that).