Blackfin arch: Initial patch to add earlyprintk support

This allows debugging of problems which happen eary in the kernel
boot process (after bootargs are parsed, but before serial subsystem
is fully initialized)

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index 26ebb0e8c431..cc789b988f3a 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -1164,6 +1164,20 @@ config DEBUG_BFIN_NO_KERN_HWTRACE
           Say Y here to disable hardware tracing in some known "jumpy" pieces
           of code so that the trace buffer will extend further back.
 
+config EARLY_PRINTK
+        bool "Early printk" 
+        default n
+        help
+          This option enables special console drivers which allow the kernel
+          to print messages very early in the bootup process.
+
+          This is useful for kernel debugging when your machine crashes very
+          early before the console code is initialized. After enabling this
+          feature, you must add "earlyprintk=serial,uart0,57600" to the
+          command line (bootargs). It is safe to say Y here in all cases, as
+          all of this lives in the init section and is thrown away after the
+          kernel boots completely.
+
 config DUAL_CORE_TEST_MODULE
         tristate "Dual Core Test Module"
         depends on (BF561)