[U-Boot] [RFC PATCH 1/4] fdt: ARM: Add device tree control of U-Boot (CONFIG_OF_CONTROL)

[Simon Glass <sjg@chromium.org>]

This adds a device tree pointer to the global data. It can be set by
board code. A later commit will add support for embedding it in U-Boot.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
 README                             |   11 +++++++++++
 arch/arm/include/asm/global_data.h |    1 +
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/README b/README
index 0886987..812805f 100644
--- a/README
+++ b/README
@@ -795,6 +795,17 @@ The following options need to be configured:
 
 		XXX - this list needs to get updated!
 
+- Device tree:
+		CONFIG_OF_CONTROL
+		If this variable is defined, U-Boot will use a device tree
+		to configure its devices, instead of relying on statically
+		compiled #defines in the board file. This option is
+		experimental and only available on a few boards. The device
+		tree is available in the global data as gd->blob.
+
+		U-Boot needs to get its device tree from somewhere. This will
+		be enabled in a future patch.
+
 - Watchdog:
 		CONFIG_WATCHDOG
 		If this variable is defined, it enables watchdog
diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
index 4fc51fd..818eced 100644
--- a/arch/arm/include/asm/global_data.h
+++ b/arch/arm/include/asm/global_data.h
@@ -73,6 +73,7 @@ typedef	struct	global_data {
 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
 	unsigned long	tlb_addr;
 #endif
+	const void	*blob;		/* Our device tree, NULL if none */
 	void		**jt;		/* jump table */
 	char		env_buf[32];	/* buffer for getenv() before reloc. */
 } gd_t;
-- 
1.7.3.1