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[#1]

MCXN547 - Best approach to load Ethernet MAC address from IFR (CMPA) at runtime?

Hello,

We are developing a product based on the MCXN547 with Zephyr RTOS 4.3.0. As part of our factory provisioning process, we program a unique EUI64 per unit into the CMPA region of the IFR (at address `0x01004190`), using the MCUXpresso Secure Provisioning Tool. From this EUI64 we derive the 6-byte Ethernet MAC address.

We would like the Ethernet driver to automatically use this MAC address at boot, instead of a static `local-mac-address` in the devicetree.

We have verified that the CMPA region at `0x01004190` is directly readable at runtime via memory-mapped access (`devmem` confirmed this).

Our question: What is the recommended approach to have the `nxp,enet-qos-mac` driver (used by the MCXN547) read the MAC address from a custom location in the IFR/CMPA at startup?

We are aware that the classic `nxp,enet-mac` driver supports `nvmem-cells` for this purpose, but we are not sure if this is also supported or achievable with the `nxp,enet-qos-mac` driver, and what the correct devicetree configuration would be for the MCXN547.

Any guidance or example from NXP or the community would be greatly appreciated.

Environment:
- MCU: MCXN547
- Zephyr: 4.3.0 (NXP fork nxp-v4.3.0)
- Driver: `drivers/ethernet/eth_nxp_enet_qos/eth_nxp_enet_qos_mac.c`
- IDE: VS Code + MCUXpresso extension
- Provisioning: MCUXpresso Secure Provisioning Tool

MCXNRe: MCXN547 - Best approach to load Ethernet MAC address from IFR (CMPA) at runtime?

If you're willing to try an alternative route, you can try Mongoose with its built-in TCP/IP stack. Mongoose allows you to redefine MG_SET_MAC_ADDRESS to your custom function.

To try,
1. Disable Zephyr TCP/IP in your project conf
2. Create mongoose/ directory, and copy mongoose.c and mongoose.h from https://github.com/cesanta/mongoose
3. Create mongoose_config.h with this:

#pragma once

// See https://mongoose.ws/documentation/#build-options
#define MG_ARCH MG_ARCH_ARMGCC
#define MG_OTA MG_OTA_MCXN

#define MG_ENABLE_TCPIP 1
#define MG_ENABLE_DRIVER_MCXN 1
#define MG_ENABLE_CUSTOM_MILLIS 1

// extern void my_function(unsigned char *mac);
// #define MG_SET_MAC_ADDRESS(mac) my_function(mac)

4. Implement "uint64_t mg_millis(void)" to return number of milliseconds since boot.

Make a Zephyr task that runs mongoose, give it 8kb stack:

struct mg_mgr mgr;
mg_mgr_init(&mgr);
for (;;) mg_mgr_poll(&mgr, 1);

And that should be it.  Redirect printf to UART to see debug logs. Also, Mongoose gives you CRA-ready OTA built-in, https://mongoose.ws/ota/

There is a pre-built test project for a slightly different MCU, https://github.com/cesanta/mongoose/tree/master/tutorials/nxp/frdm-mcxn947-make-baremetal-builtin - close mongoose repo and type "make" in that directory to build, that needs make and ARM GCC installed.

Re: MCXN547 - Best approach to load Ethernet MAC address from IFR (CMPA) at runtime?

Hi @Jorini 

Thank you for the post!

You could follow the Zephyr documentation using the option to change the MAC address at runtime: MAC Address Configuration — Zephyr Project Documentation

Please let me know if this information helps!