[U-Boot] [PATCH v4] env: export fdt_blob to the environment variable

[Thomas Chou]

Export fdt_blob to the environment variable. So that we may
use it to boot Linux.

Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
---
v2
  move the code to per board, nios2-generic.c.
v3
  move the code to generic, board_r.c.
v4
  use fdtcontroladdr as Simon suggested.

 common/board_r.c       | 3 +++
 doc/README.fdt-control | 5 ++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/common/board_r.c b/common/board_r.c
index a4facf8..d722081 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -449,6 +449,9 @@ static int initr_env(void)
 		env_relocate();
 	else
 		set_default_env(NULL);
+#ifdef CONFIG_OF_CONTROL
+	setenv_addr("fdtcontroladdr", gd->fdt_blob);
+#endif
 
 	/* Initialize from environment */
 	load_addr = getenv_ulong("loadaddr", 16, load_addr);
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 @@ address of the fdt binary blob, and will override either of the options.
 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:
 
-- 
2.1.4