upl: Add support for reading a upl handoff

Universal Payload provides a standard way of handing off control between
two firmware phases. Add support for reading the handoff information into
a structure.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/Kconfig b/boot/Kconfig
index 940389d..3010629 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -745,6 +745,25 @@
 	  This provides a way to try out standard boot on an existing boot flow.
 	  It is not enabled by default to save space.
 
+config UPL
+	bool "upl - Universal Payload Specification"
+	imply UPL_READ
+	help
+	  Provides support for UPL payloads and handoff information. U-Boot
+	  supports generating and accepting handoff information. The mkimage
+	  tool will eventually support creating payloads.
+
+if UPL
+
+config UPL_READ
+	bool "upl - Support reading a Universal Payload handoff"
+	help
+	  Provides support for decoding a UPL-format payload into a C structure
+	  which can be used elsewhere in U-Boot. This is just the reading
+	  implementation, useful for trying it out.
+
+endif  # UPL
+
 endif # BOOTSTD
 
 config LEGACY_IMAGE_FORMAT