env: export fdt_blob to the environment variable
Export fdt_blob to the environment variable. So that we may
use it to boot Linux.
Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.fdt-control b/doc/README.fdt-control
index e6d5ed0..29fd56a 100644
--- a/doc/README.fdt-control
+++ b/doc/README.fdt-control
@@ -156,7 +156,10 @@
Be aware that this environment variable is checked prior to relocation,
when only the compiled-in environment is available. Therefore it is not
possible to define this variable in the saved SPI/NAND flash
-environment, for example (it will be ignored).
+environment, for example (it will be ignored). After relocation, this
+variable will be set to the address of the newly relocated fdt blob.
+It is read-only and cannot be changed. It can optionally be used to
+control the boot process of Linux with bootm/bootz commands.
To use this, put something like this in your board header file: