IWB_WENABLER
bus_write_4(sc->sc_mem, IWB_WENABLER(i), 0);
reg = bus_read_4(sc->sc_mem, IWB_WENABLER(irq));
bus_write_4(sc->sc_mem, IWB_WENABLER(irq), reg);
reg = bus_read_4(sc->sc_mem, IWB_WENABLER(irq));
bus_write_4(sc->sc_mem, IWB_WENABLER(irq), reg);