UARTFCR
bus_space_write_1(iot, ioh, UARTFCR, wmcom_cflag2fcr(t->c_cflag));
fcr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, UARTFCR);
bus_space_write_1(sc->sc_iot, sc->sc_ioh, UARTFCR, fcr);
WMCOM_CNWRITE_1(UARTFCR, wmcom_cflag2fcr(cflag));