MEMAC_IF_MODE
reg = bus_read_4(sc->sc_base.sc_mem, MEMAC_IF_MODE);
bus_write_4(sc->sc_base.sc_mem, MEMAC_IF_MODE, reg);
reg = bus_read_4(sc->sc_base.sc_mem, MEMAC_IF_MODE);
bus_write_4(sc->sc_base.sc_mem, MEMAC_IF_MODE, reg);