UARTDR
readb(sport->port.membase + UARTDR);
readb(sport->port.membase + UARTDR);
readb(sport->port.membase + UARTDR);
writeb(ch, port->membase + UARTDR);
return sport->port.mapbase + UARTDR;
readb(port->membase + UARTDR);
writeb(c, port->membase + UARTDR);
return readb(port->membase + UARTDR);
writeb(ch, port->membase + UARTDR));
rx = readb(sport->port.membase + UARTDR);