ARM: Add an earlyprintk debug console

This patch allows an earlyprintk console if CONFIG_DEBUG_LL is enabled,
using the printch asm function.

The patch is based on the original work by Sascha Hauer.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 1a6f70e52921..feb7b11ed5b8 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -71,6 +71,14 @@ config DEBUG_LL
           in the kernel.  This is helpful if you are debugging code that
           executes before the console is initialized.
 
+config EARLY_PRINTK
+        bool "Early printk"
+        depends on DEBUG_LL
+        help
+          Say Y here if you want to have an early console using the
+          kernel low-level debugging functions. Add earlyprintk to your
+          kernel parameters to enable this console.
+
 config DEBUG_ICEDCC
         bool "Kernel low-level debugging via EmbeddedICE DCC channel"
         depends on DEBUG_LL