R_MAC_ETHERNET_ADDR
port = s->sbm_base + R_MAC_ETHERNET_ADDR;
ea_reg = __raw_readq(sc->sbm_base + R_MAC_ETHERNET_ADDR);
__raw_writeq(0, sc->sbm_base + R_MAC_ETHERNET_ADDR);
sbmac_orig_hwaddr = __raw_readq(sbm_base + R_MAC_ETHERNET_ADDR);
__raw_writeq(sbmac_orig_hwaddr, sbm_base + R_MAC_ETHERNET_ADDR);