#!/bin/sh
#
# Set Ethernet MAC address based on EEPROM settings.
#

start() {

    # Read "ethaddr" variable from U-Boot environment in EEPROM.
    #
    # Environment starts at address 0x1800 and is 1024 bytes long.
    # The environment consists of "key=value" pairs, separated by 0x00 bytes.
    #
    ethaddr_pair="$( dd if=/sys/bus/i2c/devices/0-0050/eeprom bs=1k skip=6 count=1 status=none | tr '\000' '\n' | grep ^ethaddr= )"

    if [ -z "${ethaddr_pair}" ]; then
        echo "ERROR: ethaddr not found in EEPROM enviroment" >&2
        exit 1
    fi

    ethaddr="${ethaddr_pair#ethaddr=}"

    # Check that ethaddr variable is well-formed.
    if [ -n "${ethaddr##[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]}" ]; then
        echo "ERROR: Invalid ethaddr found in EEPROM enviroment" >&2
        exit 1
    fi

    echo "Setting MAC address ${ethaddr}"

    # Configure MAC address
    ip link set dev eth0 addr ${ethaddr}
}

case "$1" in
  start)
    start
    ;;
  stop|restart|reload)
    ;;
  *)
    echo "Usage: $0 start"
    exit 1
esac