From 18a8bd949d6adb311ea816125ff65050df1f3f6e Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Sun, 15 Jul 2007 23:37:59 -0700 Subject: serial: convert early_uart to earlycon for 8250 Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and include/asm-x86_64/serial.h. the serial8250_ports need to be probed late in serial initializing stage. the console_init=>serial8250_console_init=> register_console=>serial8250_console_setup will return -ENDEV, and console ttyS0 can not be enabled at that time. need to wait till uart_add_one_port in drivers/serial/serial_core.c to call register_console to get console ttyS0. that is too late. Make early_uart to use early_param, so uart console can be used earlier. Make it to be bootconsole with CON_BOOT flag, so can use console handover feature. and it will switch to corresponding normal serial console automatically. new command line will be: console=uart8250,io,0x3f8,9600n8 console=uart8250,mmio,0xff5e0000,115200n8 or earlycon=uart8250,io,0x3f8,9600n8 earlycon=uart8250,mmio,0xff5e0000,115200n8 it will print in very early stage: Early serial console at I/O port 0x3f8 (options '9600n8') console [uart0] enabled later for console it will print: console handover: boot [uart0] -> real [ttyS0] Signed-off-by: Cc: Andi Kleen Cc: Bjorn Helgaas Cc: Russell King Cc: Gerd Hoffmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'init') diff --git a/init/main.c b/init/main.c index 0eb1c7463fe..038c7cb5239 100644 --- a/init/main.c +++ b/init/main.c @@ -453,7 +453,10 @@ static int __init do_early_param(char *param, char *val) struct obs_kernel_param *p; for (p = __setup_start; p < __setup_end; p++) { - if (p->early && strcmp(param, p->str) == 0) { + if ((p->early && strcmp(param, p->str) == 0) || + (strcmp(param, "console") == 0 && + strcmp(p->str, "earlycon") == 0) + ) { if (p->setup_func(val) != 0) printk(KERN_WARNING "Malformed early option '%s'\n", param); -- cgit v1.2.3