From ea1e225fb9a6a0dbd5a810a1de711e308bc4b175 Mon Sep 17 00:00:00 2001
From: Simon Glass <sjg@chromium.org>
Date: Tue, 21 Jun 2011 08:48:56 -0700
Subject: fdt: Add DEV_TREE_SEPARATE to provide an fdt separate from image

This adds support for an FDT to be concatenated to the u-boot-bin binary.
This is located at run-time by U-Boot.

BUG=chromium-os:11623
TEST=Either emerge with http://gerrit.chromium.org/gerrit/2961
or build manually:

make ... DEV_TREE_SEPARATE=true

and check that u-boot.dtb is built.

Change-Id: I7c8b1315d721bc957ef3fd07f167d86345868036
Reviewed-on: http://gerrit.chromium.org/gerrit/2962
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
---
 Makefile                        |  7 +++++++
 README                          |  5 +++++
 arch/arm/lib/board.c            |  3 +++
 config.mk                       |  4 ++++
 dts/Makefile                    | 13 ++++++++++---
 include/configs/tegra2-common.h |  6 +++++-
 6 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 4d0d53d7480..ebce9398f68 100644
--- a/Makefile
+++ b/Makefile
@@ -225,6 +225,9 @@ endif
 ifeq ($(CPU),ixp)
 LIBS += arch/arm/cpu/ixp/npe/libnpe.o
 endif
+ifdef DEV_TREE_SEPARATE
+ALL += $(obj)u-boot.dtb
+endif
 ifeq ($(CONFIG_OF_EMBED),y)
 LIBS += dts/dt.o
 endif
@@ -378,6 +381,10 @@ $(obj)u-boot-cflags.mk:
 		echo $(CFLAGS) | \
 			awk -v RS='[ \t\n]+' -v ORS='' -- '$(AWK_SRC)' >> $@
 
+$(obj)u-boot.dtb:	$(obj)u-boot
+		$(MAKE) -C dts binary
+		mv $(obj)dts/dt.dtb $@
+
 $(obj)u-boot.hex:	$(obj)u-boot
 		$(OBJCOPY) ${OBJCFLAGS} -O ihex $< $@
 
diff --git a/README b/README
index 38a421555cb..991010f67e6 100644
--- a/README
+++ b/README
@@ -764,6 +764,11 @@ The following options need to be configured:
 		is then picked up in board_init_f() and made available through
 		the global data structure as gd->blob.
 
+		CONFIG_OF_SEPARATE
+		If this variable is defined, U-Boot will build a device tree
+		binary. It will be called u-boot.dtb. Architecture-specific
+		code will locate it at run-time.
+
 - Watchdog:
 		CONFIG_WATCHDOG
 		If this variable is defined, it enables watchdog
diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
index 3bb80fc100a..2f34677e873 100644
--- a/arch/arm/lib/board.c
+++ b/arch/arm/lib/board.c
@@ -297,6 +297,9 @@ void board_init_f (ulong bootflag)
 #ifdef CONFIG_OF_EMBED
 	/* Get a pointer to the FDT */
 	gd->blob = _binary_dt_dtb_start;
+#elif defined CONFIG_OF_SEPARATE
+	/* FDT is at end of image */
+	gd->blob = (void*)(_end_ofs + _TEXT_BASE);
 #endif
 
 	for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
diff --git a/config.mk b/config.mk
index 4d035177ee5..ae9bbca93ae 100644
--- a/config.mk
+++ b/config.mk
@@ -188,6 +188,10 @@ ifdef VBOOT
 CPPFLAGS += -I$(VBOOT)/include/vboot
 endif
 
+ifdef DEV_TREE_SEPARATE
+CPPFLAGS += -DCONFIG_OF_SEPARATE
+endif
+
 CPPFLAGS += -I$(TOPDIR)/include
 CPPFLAGS += -fno-builtin -ffreestanding -nostdinc	\
 	-isystem $(gccincdir) -pipe $(PLATFORM_CPPFLAGS)
diff --git a/dts/Makefile b/dts/Makefile
index b885077f6a6..8863c041236 100644
--- a/dts/Makefile
+++ b/dts/Makefile
@@ -24,6 +24,9 @@ include $(TOPDIR)/config.mk
 
 LIB	= $(obj)libdts.o
 
+# We use DEV_TREE_SRC as the name of the device tree, if defined
+# If not, we use CONFIG_DEFAULT_DEVICE_TREE
+
 ifeq ($(DEV_TREE_SRC),)
 $(if $(CONFIG_DEFAULT_DEVICE_TREE),,\
 $(error Please define CONFIG_DEFAULT_DEVICE_TREE in your board header \
@@ -38,9 +41,11 @@ endif
 # the filename.
 DT_BIN	:= $(obj)dt.dtb
 
-# TODO: get arch properly for objcopy line.
-$(obj)dt.o: $(TOPDIR)/board/$(BOARDDIR)/$(DEVICE_TREE).dts
+$(DT_BIN): $(TOPDIR)/board/$(BOARDDIR)/$(DEVICE_TREE).dts
 	$(DTC) -R 4 -p 0x1000 -O dtb -o ${DT_BIN} $<
+
+# TODO: get arch properly for objcopy line.
+$(obj)dt.o: $(DT_BIN)
 	cd $(dir ${DT_BIN}) && \
 	$(OBJCOPY) -B armv5te -I binary -O elf32-littlearm \
 		$(notdir ${DT_BIN}) $@
@@ -54,7 +59,9 @@ OBJS	:= $(addprefix $(obj),$(OBJS))
 
 all:	$(obj).depend $(LIB)
 
-$(LIB):	$(OBJS)
+binary:	$(DT_BIN)
+
+$(LIB):	$(OBJS) $(DTB)
 	$(call cmd_link_o_target, $(OBJS))
 
 clean:
diff --git a/include/configs/tegra2-common.h b/include/configs/tegra2-common.h
index ae5d83fb479..629c8d1924b 100644
--- a/include/configs/tegra2-common.h
+++ b/include/configs/tegra2-common.h
@@ -36,7 +36,11 @@
 /* FDT support */
 #define CONFIG_OF_LIBFDT	/* Device tree support */
 #define CONFIG_OF_CONTROL	/* Use the device tree to set up U-Boot */
-#define CONFIG_OF_EMBED		/* Embed the device tree in U-Boot */
+
+/* Embed the device tree in U-Boot, if not otherwise handled */
+#ifndef CONFIG_OF_SEPARATE
+#define CONFIG_OF_EMBED
+#endif
 
 /*
  * High Level Configuration Options
-- 
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