ATT_IW
index = bus_space_read_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300);
bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300, reg);
bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300, val);
bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300, index);