RZN1_UART_RDMACR
dw8250_writel_ext(p, RZN1_UART_RDMACR, 0);
dw8250_writel_ext(up, RZN1_UART_RDMACR, 0);
dw8250_writel_ext(up, RZN1_UART_RDMACR, val);