PL011_MCR
CLR(sc->sc_cr, PL011_MCR(PL01X_MCR_RTS | PL01X_MCR_DTR));
SET(sc->sc_cr, PL011_MCR(sc->sc_mcr_active));
CLR(sc->sc_cr, PL011_MCR(PL01X_MCR_RTS | PL01X_MCR_DTR));
SET(sc->sc_cr, PL011_MCR(sc->sc_mcr_active));
SET(sc->sc_cr, PL011_MCR(sc->sc_mcr));