SIOP_SCNTL1
bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1, 0);
scntl1 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1);
bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1,
bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1, scntl1);