doc: uefi: capsules: Add Capsule Update porting section

Created a capsule update porting section in the documentation that outlines
the steps a board developer must do when porting from an existing reference
board implementation.

In particular, added a big warning that new capsule GUID's need to be
defined.

Signed-off-by: Jonathan Humphreys <j-humphreys@ti.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst
index 0389b269c01b78f8aa2e563ebea4b2c0fe881f6d..36ac75278fa10a8bf333b59f571df331dd8b9efe 100644 (file)
--- a/doc/develop/uefi/uefi.rst
+++ b/doc/develop/uefi/uefi.rst
@@ -631,6 +631,18 @@ where version.dtso looks like::
 The properties of image-type-id and image-index must match the value
 defined in the efi_fw_image array as image_type_id and image_index.
 
+Porting Capsule Updates to new boards
+*************************************
+
+It is important, when using a reference board as a starting point for a custom
+board, that certain steps are taken to properly support Capsule Updates.
+
+Capsule GUIDs need to be unique for each firmware and board. That is, if two
+firmwares are built from the same source but result in different binaries
+because they are built for different boards, they should have different GUIDs.
+Therefore it is important when creating support for a new board, new GUIDs are
+defined in the board's header file.  *DO NOT* reuse capsule GUIDs.
+
 Executing the boot manager
 ~~~~~~~~~~~~~~~~~~~~~~~~~~