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authorYinghai Lu <Yinghai.Lu@Sun.COM>2007-07-15 23:37:59 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:35 -0700
commit18a8bd949d6adb311ea816125ff65050df1f3f6e (patch)
tree4365db908430747a5c08cacdb4354577b7bfead7 /drivers/serial/Kconfig
parentb1c931e39327ef121797927d4b3198d370e75b9b (diff)
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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: <yinghai.lu@sun.com> Cc: Andi Kleen <ak@suse.de> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/serial/Kconfig')
-rw-r--r--drivers/serial/Kconfig14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 2adbed4..cab42cb 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -62,8 +62,22 @@ config SERIAL_8250_CONSOLE
kernel will automatically use the first serial line, /dev/ttyS0, as
system console.
+ you can set that using a kernel command line option such as
+ "console=uart8250,io,0x3f8,9600n8"
+ "console=uart8250,mmio,0xff5e0000,115200n8".
+ and it will switch to normal serial console when correponding port is
+ ready.
+ "earlycon=uart8250,io,0x3f8,9600n8"
+ "earlycon=uart8250,mmio,0xff5e0000,115200n8".
+ it will not only setup early console.
+
If unsure, say N.
+config FIX_EARLYCON_MEM
+ bool
+ depends on X86
+ default y
+
config SERIAL_8250_GSC
tristate
depends on SERIAL_8250 && GSC
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