diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_early.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_early.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c index af72ec32e404..ae6a256524d8 100644 --- a/drivers/tty/serial/8250/8250_early.c +++ b/drivers/tty/serial/8250/8250_early.c @@ -1,13 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Early serial console for 8250/16550 devices * * (c) Copyright 2004 Hewlett-Packard Development Company, L.P. * Bjorn Helgaas <bjorn.helgaas@hp.com> * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * Based on the 8250.c serial driver, Copyright (C) 2001 Russell King, * and on early_printk.c by Andi Kleen. * @@ -125,12 +122,14 @@ static void __init init_port(struct earlycon_device *device) serial8250_early_out(port, UART_FCR, 0); /* no fifo */ serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */ - divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud); - c = serial8250_early_in(port, UART_LCR); - 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); + if (port->uartclk && device->baud) { + divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud); + c = serial8250_early_in(port, UART_LCR); + 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); + } } int __init early_serial8250_setup(struct earlycon_device *device, |