ethernet { nvmem-cells = <&mac_address>; nvmem-cell-names = "mac-address"; };
You'll need 2022.07 for this I think. This is the same method which Linux uses. I added this specificly to be able to load MAC addresses from EEPROMs without needing to hard code stuff into Kconfig.
This looks good and I see Sean wired it in the U-Boot already. It should work fine with all Xilinx formats but on boards just for MAC address. (FRU format is also designed in a way that the same boards have MAC address at the same location). The code I described above is also checking in FRU format that checksums are correct and also reading more information from it for other use cases.
You might also be interested in the new NVMEM layout patch series: https://lore.kernel.org/lkml/20221118185118.1190044-1-michael@walle.cc/
-michael