On Tue, Apr 12, 2022 at 06:34:47PM +0530, Sughosh Ganu wrote:
Update the capsule update functionality related documentation to refect the additional definitions that need to be made per platform for supporting the capsule update feature.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org
Changes since V5: None
doc/develop/uefi/uefi.rst | 51 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-)
diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst index fe337c88bd..b766aecf67 100644 --- a/doc/develop/uefi/uefi.rst +++ b/doc/develop/uefi/uefi.rst @@ -312,8 +312,8 @@ Run the following command .. code-block:: console
$ mkeficapsule \
--index 1 --instance 0 \[--fit <FIT image> | --raw <raw image>] \
--index <index> --instance 0 \--guid <image GUID> \ <capsule_file_name>Performing the update @@ -333,6 +333,53 @@ won't be taken over across the reboot. If this is the case, you can skip this feature check with the Kconfig option (CONFIG_EFI_IGNORE_OSINDICATIONS) set.
+A few values need to be defined in the board file for performing the +capsule update. These values are defined in the board file by +initialisation of a structure which provides information needed for +capsule updates. The following structures have been defined for +containing the image related information
+.. code-block:: c
- struct efi_fw_images {
Why "images" (in the plural)?
efi_guid_t image_type_id;u16 *fw_name;u8 image_index;- };
Why not add "version" and "last_attempt_version" which is expected to be easily implemented in this structure.
- struct efi_capsule_update_info {
const char *dfu_string;struct efi_fw_images *images;- };
+A string is defined which is to be used for populating the +dfu_alt_info variable. This string is used by the function +set_dfu_alt_info. Instead of taking the variable from the environment, +the capsule update feature requires that the variable be set through +the function, since that is more robust. Allowing the user to change +the location of the firmware updates is not a very secure +practice. Getting this information from the firmware itself is more +secure, assuming the firmware has been verified by a previous stage +boot loader.
+The firmware images structure defines the GUID values, image index +values and the name of the images that are to be updated through +the capsule update feature. These values are to be defined as part of +an array. These GUID values would be used by the Firmware Management +Protocol(FMP) to populate the image descriptor array and also +displayed as part of the ESRT table. The image index values defined in +the array should be one greater than the dfu alt number that +corresponds to the firmware image. So, if the dfu alt number for an +image is 2, the value of image index in the fw_images array for that +image should be 3. The dfu alt number can be obtained by running the +following command::
- dfu list
+When using the FMP for FIT images, the image index value needs to be +set to 1.
The explanation would be correct, but it's not quite easy to understand, in particular, index in case of raw. You should add some examples here.
-Takahiro Akashi
Finally, the capsule update can be initiated by rebooting the board.
Enabling Capsule Authentication
2.25.1