Code update: Add PLDM package and EM configuration
PLDM image packaging can be used as one of the standardized option for
firmware image packages. Provide details on appropriate image
descriptors that can be used by non-PLDM code updaters for image
validation and how to model this information in entity manager
configuration for firmware image validation and device access.
Related PR:
https://gerrit.openbmc.org/c/openbmc/entity-manager/+/75947
Change-Id: I103969f70cbdf0aadf0518c273c3e8925ce24b90
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/designs/code-update.md b/designs/code-update.md
index 5aca23c..314bb1b 100644
--- a/designs/code-update.md
+++ b/designs/code-update.md
@@ -198,6 +198,60 @@
image format for the firmware image. This fulfills the
[Requirement# 7](#requirements).
+#### PLDM Image Packaging
+
+The PLDM for
+[Firmware Update Specification](https://www.dmtf.org/sites/default/files/standards/documents/DSP0267_1.3.0.pdf)
+provides a standardized packaging format for images, incorporating both standard
+and user-defined descriptors. This format can be utilized to package firmware
+update images for non-PLDM devices as well. For such devices, the CodeUpdater
+will parse the entity manager configuration to identify applicable PLDM
+descriptors, which can include but are not limited to the following -
+
+| PLDM Package Descriptor | Decsriptor Type | Description |
+| :---------------------: | :-------------: | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |
+| IANA Enterprise ID | Standard | [IANA Enterprise Id](https://www.iana.org/assignments/enterprise-numbers/enterprise-numbers) of the hardware vendor |
+| ASCII Model | Standard | Compatible hardware name (com.\<vendor\>.Hardware.\<XXX\>) specified by hardware vendor in [phosphor-dbus-interfaces](https://github.com/openbmc/phosphor-dbus-interfaces/tree/master/yaml/com). |
+
+#### Entity Manager Configuration
+
+The entity manager configuration can provide firmware-related information as
+part of board configurations, which can be utilized for firmware validation and
+modeling device access details. These D-Bus objects can then be consumed by the
+CodeUpdater service to manage updates for the relevant firmware entities.
+
+For common firmware info definition
+[refer](https://gerrit.openbmc.org/c/openbmc/entity-manager/+/75947)
+
+The following example is one such instance of this definition for an i2c CPLD
+device firmware.
+
+```json
+"Exposes": [
+ ...
+ {
+ "Name": "MB_LCMX02_2000HC",
+ "Type": "CPLDFirmware",
+ ...
+ "FirmwareInfo" :
+ {
+ "VendorIANA": 0000A015,
+ "CompatibleHardware": "com.meta.Hardware.Yosemite4.MedusaBoard.CPLD.LCMX02_2000HC"
+ }
+ ...
+ },
+ ...
+]
+```
+
+- `Name`: The name of the firmware entity instance.
+- `Type`: This field is used by the CodeUpdater service to determine which
+ firmware EM configurations it should process.
+- `VendorIANA`: This field maps to the `IANA Enterprise ID` descriptor in PLDM
+ package header.
+- `CompatibleHardware`: This field maps to the `ASCII Model` descriptor in PLDM
+ package header.
+
### Multi part Images
A multi part image has multiple component images as part of one image package.