RDA_UART_CTRL
val = rda_uart_read(port, RDA_UART_CTRL);
rda_uart_write(port, val, RDA_UART_CTRL);
ctrl = rda_uart_read(port, RDA_UART_CTRL);
rda_uart_write(port, ctrl, RDA_UART_CTRL);
val = rda_uart_read(port, RDA_UART_CTRL);
rda_uart_write(port, val, RDA_UART_CTRL);
val = rda_uart_read(port, RDA_UART_CTRL);
rda_uart_write(port, val, RDA_UART_CTRL);