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 sjg@chromium.org --- Makefile | 8 +++++++- doc/README.fdt-control | 16 ++++++++++++++-- 2 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile index 07abef4..c651af0 100644 --- a/Makefile +++ b/Makefile @@ -416,9 +416,15 @@ endif
all: $(ALL-y) $(SUBDIR_EXAMPLES)
+# Allow a device tree binary to be given as a make argument +ifneq ($(DEV_TREE_BIN),) +$(obj)u-boot.dtb: + cp $(DEV_TREE_BIN) $@ +else $(obj)u-boot.dtb: checkdtc $(obj)u-boot $(MAKE) -C dts binary mv $(obj)dts/dt.dtb $@ +endif
$(obj)u-boot-dtb.bin: $(obj)u-boot.bin $(obj)u-boot.dtb cat $^ >$@ @@ -452,7 +458,7 @@ ifndef CONFIG_SYS_UBOOT_START CONFIG_SYS_UBOOT_START := 0 endif
-$(obj)u-boot.img: $(obj)u-boot.bin +$(obj)u-boot.img: $(obj)u-boot$(if $(CONFIG_OF_SEPARATE),-dtb,).bin $(obj)tools/mkimage -A $(ARCH) -T firmware -C none \ -O u-boot -a $(CONFIG_SYS_TEXT_BASE) \ -e $(CONFIG_SYS_UBOOT_START) \ diff --git a/doc/README.fdt-control b/doc/README.fdt-control index 86bae68..8a4aa7a 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.