DMAMSK_REG_W
mask = bus_space_read_2(sc->sc_iot, sc->sc_ioh, DMAMSK_REG_W);
bus_space_write_2(sc->sc_iot, sc->sc_ioh, DMAMSK_REG_W, DMAMSKAIN);
mask = bus_space_read_2(sc->sc_iot, sc->sc_ioh, DMAMSK_REG_W);
bus_space_write_2(sc->sc_iot, sc->sc_ioh, DMAMSK_REG_W, DMAMSKAOUT);
mask = bus_space_read_2(sc->sc_iot, sc->sc_ioh, DMAMSK_REG_W);
bus_space_write_2(sc->sc_iot, sc->sc_ioh, DMAMSK_REG_W, DMAMSKFOUT);