serial8250_early_out
serial8250_early_out(port, UART_LCR, UART_LCR_WLEN8); /* 8n1 */
serial8250_early_out(port, UART_IER, ier & UART_IER_UUE); /* no interrupt */
serial8250_early_out(port, UART_FCR, 0); /* no fifo */
serial8250_early_out(port, UART_MCR, UART_MCR_DTR | UART_MCR_RTS);
serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
serial8250_early_out(port, UART_DLL, divisor & 0xff);
serial8250_early_out(port, UART_DLM, (divisor >> 8) & 0xff);
serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB);
serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
serial8250_early_out(port, UART_TX, c);