IXPCLK_CLEAR
bus_space_write_4(sc->sc_iot, sc->sc_ioh, IXPCLK_CLEAR, 0);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, IXPCLK_CLEAR, IXPT_CLEAR);
IXPCLK_CLEAR, 1);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, IXPCLK_CLEAR, IXPT_CLEAR);