fdt: ARM: Add fdtcontroladdr to set device tree address in environment

This adds support for a new environment variable called 'fdtcontroladdr'. If
defined, the hex address is used as the address of the control fdt for U-Boot.

Note: I have not changed CONFIG_PRAM section as I already have an
outstanding patch on that.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/README b/README
index 558f011..a3b62e1 100644 (file)
--- a/README
+++ b/README
@@ -3499,6 +3499,10 @@ List of environment variables (most likely not complete):
                  add the information it needs into it, and the memory
                  must be accessible by the kernel.
 
+  fdtcontroladdr- if set this is the address of the control flattened
+                 device tree used by U-Boot when CONFIG_OF_CONTROL is
+                 defined.
+
   i2cfast      - (PPC405GP|PPC405EP only)
                  if set to 'y' configures Linux I2C driver for fast
                  mode (400kHZ). This environment variable is used in

diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
index bd6d4e3..bae2892 100644 (file)
--- a/arch/arm/lib/board.c
+++ b/arch/arm/lib/board.c
@@ -286,6 +286,9 @@ void board_init_f(ulong bootflag)
        /* FDT is at end of image */
        gd->fdt_blob = (void *)(_end_ofs + _TEXT_BASE);
 #endif
+       /* Allow the early environment to override the fdt address */
+       gd->fdt_blob = (void *)getenv_ulong("fdtcontroladdr", 16,
+                                               (uintptr_t)gd->fdt_blob);
 
        for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
                if ((*init_fnc_ptr)() != 0) {

diff --git a/doc/README.fdt-control b/doc/README.fdt-control
index 3f8bb5a..85bda03 100644 (file)
--- a/doc/README.fdt-control
+++ b/doc/README.fdt-control
@@ -144,6 +144,18 @@ and then flash image.bin onto your board.
 
 You cannot use both of these options at the same time.
 
+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.
+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).
+
+To use this, put something like this in your board header file:
+
+#define CONFIG_EXTRA_ENV_SETTINGS      "fdtcontroladdr=10000\0"
+
 
 Limitations
 -----------