[PATCH v6 7/8] doc: uefi: add firmware versioning documentation

[Masahisa Kojima]

This commit describes the procedure to add the firmware version
into the capsule file.

Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
---
Newly created in v6

 doc/develop/uefi/uefi.rst | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst
index ffe25ca231..efab0fc7b1 100644
--- a/doc/develop/uefi/uefi.rst
+++ b/doc/develop/uefi/uefi.rst
@@ -510,6 +510,35 @@ where signature.dts looks like::
             };
     };
 
+Enabling Firmware Versioning
+****************************
+
+The UEFI specification does not define the firmware versioning mechanism.
+EDK II reference implementation inserts the FMP Payload Header right before
+the payload. It coutains the fw_version and lowest supported version,
+EDK II reference implementation uses these information to implement the
+firmware versioning and anti-rollback protection, the firmware version and
+lowest supported version is stored into EFI non-volatile variable.
+
+In U-Boot, the firmware versioning is implemented utilizing
+the FMP Payload Header same as EDK II reference implementation,
+reads the FMP Payload Header and stores the firmware version into
+"FmpStateXXXX" EFI non-volatile variable. XXXX indicates the image index,
+since FMP protocol handles multiple image indexes.
+
+
+1. Run the following command to add firmware version into the capsule file
+
+.. code-block:: console
+
+    $ mkeficapsule --monotonic-count 1 \
+      --private-key CRT.key \
+      --certificate CRT.crt \
+      --index 1 --instance 0 \
+      --fw-version 5 \
+      [--fit | --raw | --guid <guid-string] \
+      <image_blob> <capsule_file_name>
+
 Executing the boot manager
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-- 
2.17.1