RGMII0_FER
fer = bus_space_read_4(sc->sc_iot, sc->sc_rgmiih, RGMII0_FER);
bus_space_write_4(sc->sc_iot, sc->sc_rgmiih, RGMII0_FER, fer);
fer = bus_space_read_4(sc->sc_iot, sc->sc_rgmiih, RGMII0_FER);
bus_space_write_4(sc->sc_iot, sc->sc_rgmiih, RGMII0_FER, fer);