summaryrefslogtreecommitdiff
path: root/doc
diff options
context:
space:
mode:
authorSimon Glass <sjg@chromium.org>2014-06-02 22:04:50 -0600
committerTom Rini <trini@ti.com>2014-06-11 16:25:46 -0400
commit63b4b5bae52e48528876e13e858ef934ac2e4a3b (patch)
treee0143f2b83f7bbba3d30f97785dad6f2624eb932 /doc
parent31890ae299bca739c58b311dfced0bb199a5f520 (diff)
downloadu-boot-imx-63b4b5bae52e48528876e13e858ef934ac2e4a3b.zip
u-boot-imx-63b4b5bae52e48528876e13e858ef934ac2e4a3b.tar.gz
u-boot-imx-63b4b5bae52e48528876e13e858ef934ac2e4a3b.tar.bz2
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 <sjg@chromium.org>
Diffstat (limited to 'doc')
-rw-r--r--doc/README.fdt-control16
1 files changed, 14 insertions, 2 deletions
diff --git a/doc/README.fdt-control b/doc/README.fdt-control
index 0ceebe7..be92d7a 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.