upl: Add initial documentation
Add some documentation to explain the basic concept along with a link
to the full spec.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/usage/cmd/upl.rst b/doc/usage/cmd/upl.rst
index a64063d..8d6ea5d 100644
--- a/doc/usage/cmd/upl.rst
+++ b/doc/usage/cmd/upl.rst
@@ -16,8 +16,8 @@
-----------
The *upl* command is used to test U-Boot's support for the Universal Payload
-Specification (UPL) firmware standard. It allows creation of a fake handoff for
-use in testing.
+Specification (UPL) firmware standard (see :doc:`../upl`). It allows creation of
+a fake handoff for use in testing.
upl write