Before issuing an API call to the PMU, a PU must wait until its previous API call is processed by the PMU. A check for completion of a PMU action can be implemented by reading the corresponding IPI observation register.
An API call is issued by populating the IPI payload buffer with API data and triggering an IPI interrupt to the PMU. In case of a blocking API call, the PMU will respond by populating the response buffer with the status of the operation and up to 3 values. See Additional Resources and Legal Notices for a list of all the errors that can be sent by the PMU if a PM operation was unsuccessful. The PU must wait until the PMU has finished processing the API call prior to reading the response buffer, to ensure that the data in the response buffer is valid.
