[U-Boot-Users] [PATCH] Document 'bootm_low' and 'bootm_size' environment variables

[Bartlomiej Sieka]

Signed-off-by: Bartlomiej Sieka <tur at semihalf.com>
---
Kumar, this patch pertains to your commit "[new uImage] Provide ability to
restrict region used for boot images", id d3f2fa0d -- could you review
and confirm that the documentation is OK? Thanks.

 README |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/README b/README
index 5d059e7..a0dfe73 100644
--- a/README
+++ b/README
@@ -1995,7 +1995,10 @@ Configuration Settings:
 		Maximum size of memory mapped by the startup code of
 		the Linux kernel; all data that must be processed by
 		the Linux kernel (bd_info, boot arguments, eventually
-		initrd image) must be put below this limit.
+		initrd image) must be put below this limit, unless
+		"bootm_low" enviroment variable is defined and non-zero.
+		In such case all data for the Linux kernel must be
+		between "bootm_low" and "bootm_low" + CFG_BOOTMAPSZ.
 
 - CFG_MAX_FLASH_BANKS:
 		Max number of Flash memory banks
@@ -2733,6 +2736,20 @@ Some configuration options can be set using Environment Variables:
 
   bootfile	- Name of the image to load with TFTP
 
+  bootm_low	- Memory range available for image processing in the bootm
+		  command can be restricted. This variable is given as
+		  a hexadecimal number and defines lowest address allowed
+		  for use by the bootm command. See also "bootm_size"
+		  environment variable. Address defined by "bootm_low" is
+		  also the base of the initial memory mapping for the Linux
+		  kernel -- see the descripton of CFG_BOOTMAPSZ.
+
+  bootm_size	- Memory range available for image processing in the bootm
+		  command can be restricted. This variable is given as
+		  a hexadecimal number and defines the size of the region
+		  allowed for use by the bootm command. See also "bootm_low"
+		  environment variable.
+
   autoload	- if set to "no" (any string beginning with 'n'),
 		  "bootp" will just load perform a lookup of the
 		  configuration from the BOOTP server, but not try to