UART_DUMMY_RSR_RX
rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
port->ignore_status_mask |= UART_DUMMY_RSR_RX;
port->ignore_status_mask |= UART_DUMMY_RSR_RX;
rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX;