GICD_CTLR
v = bus_space_read_4(sc->sc_iot, sc->sc_d_ioh, GICD_CTLR);
ctrl = bus_space_read_4(sc->sc_iot, sc->sc_d_ioh, GICD_CTLR);
ctrl = bus_space_read_4(sc->sc_iot, sc->sc_d_ioh, GICD_CTLR);
bus_space_write_4(sc->sc_iot, sc->sc_d_ioh, GICD_CTLR, ctrl | bits);