ifconfig -a
will list all detected interfaces, then you can use
ip link set dev XXX up
ifconfig XXX 192.168.1.1 netmask 255.255.255.0 up
eth0 is the RGMII device interfacing to the switch, the switch ports have names like “wan” and “lan0”. These names are defined in the flat device tree file (*.dtb) loaded by u-boot.