[U-Boot] [PATCH v2] Adds general Freescale external debugger support

[Roy Zang]

This patch adds general Freescale powerpc external debugger support.
Patch is tested on 85xx/QorIQ platforms in u-boot with CodeWarrior.
CONFIG_EXT_DEBUGGER should be defined if the u-boot needs to be
debugged by external debugger.
To use the  external debug funciton, the make command can be just as
make CONFIG_EXT_DEBUGGER=1
or define CONFIG_EXT_DEBUGGER in the board header file.

Signed-off-by: Roy Zang <tie-fei.zang at freescale.com>
Cc: Wood Scott-B07421 <B07421 at freescale.com>
Cc: Kumar Gala <galak at kernel.crashing.org>
---
Consider the comment from Wolfgang Denk
http://lists.denx.de/pipermail/u-boot/2010-October/080689.html

 README                 |    4 ++++
 arch/powerpc/config.mk |    3 +++
 2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/README b/README
index 755d17c..6162fa6 100644
--- a/README
+++ b/README
@@ -2885,6 +2885,10 @@ Low Level (hardware related) configuration options:
 		that is executed before the actual U-Boot. E.g. when
 		compiling a NAND SPL.
 
+- CONFIG_EXT_DEBUGGER
+		Adds external debugger support. Extra build option will be
+		added to support external debugger.
+
 Building the Software:
 ======================
 
diff --git a/arch/powerpc/config.mk b/arch/powerpc/config.mk
index 2912604..9af9647 100644
--- a/arch/powerpc/config.mk
+++ b/arch/powerpc/config.mk
@@ -53,3 +53,6 @@ endif
 ifeq ($(CROSS_COMPILE),powerpc-openbsd-)
 PLATFORM_CPPFLAGS+= -D__PPC__
 endif
+ifdef CONFIG_EXT_DEBUGGER
+PLATFORM_CPPFLAGS+= -ggdb -Wa,-gdwarf2
+endif
-- 
1.7.3.5