UART_TX_RX_FIFO
uartaddr[UART_TX_RX_FIFO / 4] = htole32(c);
bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);
bus_space_write_4(iot, ioh, UART_TX_RX_FIFO, *sc->sc_tba);
bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);
bus_space_write_4(iot, ioh, UART_TX_RX_FIFO, *sc->sc_tba);
c = 0xff & bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);
cin = bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);
bus_space_write_4(iot, ioh, UART_TX_RX_FIFO, c);