Automatic software update from TFTP server

The auto-update feature allows to automatically download software updates
from a TFTP server and store them in Flash memory during boot. Updates are
contained in a FIT file and protected with SHA-1 checksum.

More detailed description can be found in doc/README.update.

Signed-off-by: Rafal Czubak <rcz@semihalf.com>
Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
diff --git a/README b/README
index 8802304..36d740f 100644
--- a/README
+++ b/README
@@ -1740,6 +1740,14 @@
 		example, some LED's) on your board. At the moment,
 		the following checkpoints are implemented:
 
+- Automatic software updates via TFTP server
+		CONFIG_UPDATE_TFTP
+		CONFIG_UPDATE_TFTP_CNT_MAX
+		CONFIG_UPDATE_TFTP_MSEC_MAX
+
+		These options enable and control the auto-update feature;
+		for a more detailed description refer to doc/README.update.
+
 Legacy uImage format:
 
   Arg	Where			When
@@ -2814,6 +2822,10 @@
 		  allowed for use by the bootm command. See also "bootm_low"
 		  environment variable.
 
+  updatefile	- Location of the software update file on a TFTP server, used
+		  by the automatic software update feature. Please refer to
+		  documentation in doc/README.update for more details.
+
   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