DCR
DUMP_BSC_REG(DCR);
uint32_t dcr = bus_space_read_4(sc->sc_bst, sc->sc_bsh, DCR);
bus_space_write_4(sc->sc_bst, sc->sc_bsh, DCR, dcr);
UART_WRITE(uart1base, DCR, 0x01); /* enable DUART mode */