autoboot: Improve docs for CONFIG_AUTOBOOT_ENCRYPTION
This option is not documented properly at present. Fix it.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.autoboot b/doc/README.autoboot
index eeb7e4c..de35f30 100644
--- a/doc/README.autoboot
+++ b/doc/README.autoboot
@@ -132,6 +132,21 @@
provides an escape sequence from the limited "password"
strings.
+ CONFIG_AUTOBOOT_ENCRYPTION
+
+ "bootstopkeysha256" environment variable
+
+ - Hash value of the input which unlocks the device and
+ stops autoboot.
+
+ This option allows a string to be entered into U-Boot to stop the
+ autoboot. The string itself is hashed and compared against the hash
+ in the environment variable 'bootstopkeysha256'. If it matches then
+ boot stops and a command-line prompt is presented.
+
+ This provides a way to ship a secure production device which can also
+ be accessed at the U-Boot command line.
+
CONFIG_RESET_TO_RETRY
(Only effective when CONFIG_BOOT_RETRY_TIME is also set)