The system layer of the PM framework is implemented on the Zynq UltraScale+ MPSoC using inter-processor interrupts (IPIs). To issue an EEMI API call, a PU will write the API data (API ID and arguments) into the IPI request buffer and then trigger the IPI to the PMU.
After the PM controller processes the request it will send the acknowledge depending on the particular EEMI API and provided arguments.