diff options
authorSimon Glass <>2014-06-02 22:04:50 -0600
committerTom Rini <>2014-06-11 16:25:46 -0400
commit63b4b5bae52e48528876e13e858ef934ac2e4a3b (patch)
parent31890ae299bca739c58b311dfced0bb199a5f520 (diff)
fdt: Add DEV_TREE_BIN option to specify a device tree binary file
In some cases, an externally-built device tree binary is required to be attached to U-Boot. An example is when using image signing, since in that case the .dtb file must include the public keys. Add a DEV_TREE_BIN option to the Makefile, and update the documentation. Usage is something like: make DEV_TREE_BIN=boot/am335x-boneblack-pubkey.dtb Signed-off-by: Simon Glass <>
3 files changed, 19 insertions, 3 deletions
diff --git a/Makefile b/Makefile
index e77b639a04..866a8c4f30 100644
--- a/Makefile
+++ b/Makefile
@@ -832,7 +832,7 @@ MKIMAGEFLAGS_u-boot.kwb = -n $(srctree)/$(CONFIG_SYS_KWD_CONFIG:"%"=%) \
MKIMAGEFLAGS_u-boot.pbl = -n $(srctree)/$(CONFIG_SYS_FSL_PBL_RCW:"%"=%) \
-R $(srctree)/$(CONFIG_SYS_FSL_PBL_PBI:"%"=%) -T pblimage
-u-boot.img u-boot.kwb u-boot.pbl: u-boot.bin FORCE
+u-boot.img u-boot.kwb u-boot.pbl: u-boot$(if $(CONFIG_OF_SEPARATE),-dtb,).bin FORCE
$(call if_changed,mkimage)
MKIMAGEFLAGS_u-boot-dtb.img = $(MKIMAGEFLAGS_u-boot.img)
diff --git a/doc/README.fdt-control b/doc/README.fdt-control
index 0ceebe7aa6..be92d7ae88 100644
--- a/doc/README.fdt-control
+++ b/doc/README.fdt-control
@@ -122,7 +122,8 @@ This should include your CPU or SOC's device tree file, placed in
arch/<arch>/dts, and then make any adjustments required.
If CONFIG_OF_EMBED is defined, then it will be picked up and built into
-the U-Boot image (including u-boot.bin).
+the U-Boot image (including u-boot.bin). This is suitable for debugging
+and development only and is not recommended for production devices.
If CONFIG_OF_SEPARATE is defined, then it will be built and placed in
a u-boot.dtb file alongside u-boot.bin. A common approach is then to
@@ -130,7 +131,10 @@ join the two:
cat u-boot.bin u-boot.dtb >image.bin
-and then flash image.bin onto your board.
+and then flash image.bin onto your board. Note that U-Boot creates
+u-boot-dtb.bin which does the above step for you also. If you are using
+CONFIG_SPL_FRAMEWORK, then u-boot.img will be built to include the device
+tree binary.
If CONFIG_OF_HOSTFILE is defined, then it will be read from a file on
startup. This is only useful for sandbox. Use the -d flag to U-Boot to
@@ -138,6 +142,14 @@ specify the file to read.
You cannot use more than one of these options at the same time.
+To use a device tree file that you have compiled yourself, pass
+DEV_TREE_BIN=<filename> to 'make', as in:
+ make DEV_TREE_BIN=boot/am335x-boneblack-pubkey.dtb
+Then U-Boot will copy that file to u-boot.dtb, put it in the .img file
+if used, and u-boot-dtb.bin.
If you wish to put the fdt at a different address in memory, you can
define the "fdtcontroladdr" environment variable. This is the hex
address of the fdt binary blob, and will override either of the options.
diff --git a/dts/Makefile b/dts/Makefile
index 3fca5f5c2f..f344efe64b 100644
--- a/dts/Makefile
+++ b/dts/Makefile
@@ -12,7 +12,11 @@ ifeq ($(DEVICE_TREE),)
DEVICE_TREE := unset
+ifneq ($(DEV_TREE_BIN),)
DTB := arch/$(ARCH)/dts/$(DEVICE_TREE).dtb
$(obj)/dt.dtb: $(DTB) FORCE
$(call if_changed,shipped)
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