From 63b4b5bae52e48528876e13e858ef934ac2e4a3b Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Mon, 2 Jun 2014 22:04:50 -0600 Subject: 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 --- doc/README.fdt-control | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'doc') 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//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= 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. -- cgit v1.2.1