Power Management Events - 2021.2 English

Zynq UltraScale+ MPSoC Software Developer Guide

Document ID
UG1137
Release Date
2021-10-27
Version
2021.2 English

The PM Controller is event-driven, and all of the operations are triggered by one of the following events:

  • EEMI API events triggered via IPI0 interrupt.
  • Wake events triggered via GPI1 interrupt.
  • Sleep events triggered via GPI2 interrupt.
  • Timer event triggered via PIT2 interrupt.

EEMI API Events

EEMI API events are software-generated events. The events are triggered via IPI interrupt when a PM master initiates an EEMI API call to the PMU. The PM Controller handles the EEMI request and may send back an acknowledgment (if one is requested.) An EEMI request often triggers a change in the power state of a node or a master, with some exceptions.

Wake Events

Wake events are hardware-generated events. They are triggered by a peripheral signaling that a PM master should be woken-up. All wake events are triggered via the GPI1 interrupt.

The following wake events are supported by the PM controller:

  • GIC wake events which signal that a CPU shall be woken up due to an interrupt triggered by a hardware resource to the associated GIC interface. The following GIC wake events are supported:
    • APU[3:0]An event for each APU processor
    • RPU[1:0]An event for each RPU processor
  • FPD wake event directed by the GIC Proxy. This wake event is triggered when any of the wake sources enabled prior to suspending. The purpose of this event is to trigger a wake-up of APU master when FPD is powered down. If FPD is not powered down, none of the wake signals would propagate through FPD wake. Instead, the wake would propagate through GIC wake if the associated interrupt at the GIC is properly enabled. All wake events targeted to the RPU propagate via the associated GIC wake.

Sleep Events

Sleep events are software-generated events. The events are triggered by a CPU after it finalizes the suspend procedure with the aim to signal to the PMU that it is ready to be put in a low power state. All sleep events are triggered via GPI2 interrupt.

The following sleep events are supported:

  • APU[3:0]An event for each APU processor
  • RPU[1:0]An event for each RPU processor

When the PM controller PM Controller receives the sleep event for a particular CPU, the CPU is put into a low power state.

Timer Event

Timer event is hardware-generated event. It is triggered by a hardware timer when a period of time expires. The event is used for power management timeout accounting and it is triggered via PIT2 interrupt.