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Versal ACAP Platform Management Unit provides centralized power state handling, clock management, reset management, pin control management. Platform Management (PM) services are used by calling PM API via IPI to firmware. The PM interface can be used to access secure resources by implementing custom PM APIs in firmware. This document describes the end-to-end flow for adding new PM API in firmware and how it can be used in any Linux driver.

Source code links mentioned in this document are from the 2020.2 release. So, you may not find the same source code on the same line in another release.


Knowledge of Versal ACAP Platform Management Software Architecture. Please refer to the following sections from Versal ACAP system software developers guide.


Implement the PM API function


Add new PM API as valid feature in XilPM


Changes in ATF


Add the same PM API ID defined in xilpm/server.


Add new PM API as valid feature in ATF

As explained in section , it is important add new PM API and to make sure the API in firmware, ATF and Linux are in sync, newly added PM API needs be added as valid feature in ATF also.

  • Add the newly added API as a valid feature and return the appropriate API version in pm_feature_check().The feature check function in ATF provides the version of the PM API defined in ATF. This is to make sure the API in firmware, ATF and Linux are in sync.

  • Example of Marking PM_IOCTL as valid feature in ATF: PM_IOCTL

Changes in Linux ZynqMP Firmware Driver


Add same PM API ID defined in xilpm/server and ATF.

  • PM API IDs are defined in xlnx-zynqmp.h

  • Add the new PM API ID at the end of the list before PM_API_MAX as enum in pm_api_id{}

As per Linux guideline from mainline communityy, enum values should be assigned explicitly.

Function to be used by another driver to call PM API


No change in ATF is required if you are just adding new IOCTL ID.