@@ -318,6 +318,33 @@ Run the following command
--guid <image GUID> \
<capsule_file_name>
+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.
+
+To add the fw_version into the FMP Payload Header,
+add --fw-version option in mkeficapsule tool.
+
+.. code-block:: console
+
+ $ mkeficapsule \
+ --index <index> --instance 0 \
+ --guid <image GUID> \
+ --fw-version 5 \
+ <capsule_file_name>
+
+If the --fw-version option is not set, FMP Payload Header is not inserted
+and fw_version is set as 0.
+
Performing the update
*********************
This commit describes the procedure to add the firmware version into the capsule file. Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org> --- No update since v7 Changes in v7: - move documentation into "Creating a capsule file" - cleary describe the --fw-version option Newly created in v6 doc/develop/uefi/uefi.rst | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)