Allow pick device tree by specifying an environment variable.

The default device tree used by the make system is
board/nvidia/seaboard/tegra2-seaboard.dts, it is expected to be
defined in the main config file used by the related targets. If
'DEV_TREE_SRC' is defined in the environment, the file
board/nvidia/seaboard/${DEV_TREE_SRC} is used as the device tree
source instead. ./mkconfig is being restored to remove the device
tree related changes.

BUG=chromium-os:834
TEST=manual

Change-Id: I2232c5f4413b719057ec3def77ca03a78068c3c9
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/2776
Reviewed-by: Simon Glass <sjg@chromium.org>

3 files changed, 9 insertions, 4 deletions

diff --git a/dts/Makefile b/dts/Makefile
index 9e4cc841e6c..47b707ec7da 100644
--- a/dts/Makefile
+++ b/dts/Makefile
@@ -24,6 +24,12 @@ include $(TOPDIR)/config.mk
 
 LIB	= $(obj)libdts.o
 
+ifeq ($(DEV_TREE_SRC),)
+DEVICE_TREE = $(subst ",,$(CONFIG_DEFAULT_DEVICE_TREE))
+else
+DEVICE_TREE = $(DEV_TREE_SRC)
+endif
+
 # Use a constant name for this so we can access it from C code.
 # objcopy doesn't seem to allow us to set the symbol name independently of
 # the filename.
diff --git a/include/configs/seaboard.h b/include/configs/seaboard.h
index 5c4aa4b00bf..57af139666c 100644
--- a/include/configs/seaboard.h
+++ b/include/configs/seaboard.h
@@ -192,4 +192,6 @@
 	CONFIG_EXTRA_ENV_SETTINGS_COMMON \
 	"board=seaboard\0" \
 
+#define CONFIG_DEFAULT_DEVICE_TREE "tegra2-seaboard"
+
 #endif /* __CONFIG_H */
diff --git a/mkconfig b/mkconfig
index 04ea12a4643..6ff533f3393 100755
--- a/mkconfig
+++ b/mkconfig
@@ -127,10 +127,7 @@ echo "BOARD  = ${board}" >> config.mk
 
 [ "${vendor}" ] && echo "VENDOR = ${vendor}" >> config.mk
 
-if [ -n "${soc}" ] ; then
-	echo "SOC    = ${soc}" >> config.mk
-	echo "DEVICE_TREE = ${soc}-${board}" >> config.mk
-fi
+[ "${soc}"    ] && echo "SOC    = ${soc}"    >> config.mk
 
 # Assign board directory to BOARDIR variable
 if [ -z "${vendor}" ] ; then