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/common/main.c b/common/main.c
index 187ef8a..c06ea07 100644
--- a/common/main.c
+++ b/common/main.c
@@ -56,6 +56,9 @@
 
 extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
 
+#if defined(CONFIG_UPDATE_TFTP)
+void update_tftp (void);
+#endif /* CONFIG_UPDATE_TFTP */
 
 #define MAX_DELAY_STOP_STR 32
 
@@ -301,6 +304,10 @@
 	trab_vfd (bmp);
 #endif	/* CONFIG_VFD && VFD_TEST_LOGO */
 
+#if defined(CONFIG_UPDATE_TFTP)
+	update_tftp ();
+#endif /* CONFIG_UPDATE_TFTP */
+
 #ifdef CONFIG_BOOTCOUNT_LIMIT
 	bootcount = bootcount_load();
 	bootcount++;