Design

Zynq UltraScale plus MPSoC Power Management
Release Date
2023-04-24
  1. Suspend and Power Off:
    1. Detect normal suspend (LPD on) vs. power off suspend (ZU+ off).
    2. Saving volatile memory contents and state information.
    3. Signal external power controller to power down the ZU+
  2. Power On and Resume:
    1. Power up APU/RPU just like during POR
    2. Detect resume mode vs. POR.
    3. Restore volatile memory contents and state information.

NODE_EXTERN

When user performs the power-off suspend, the wake-up is triggered from the external entity instead of any SoC peripheral. This wake-up device is referred as NODE_EXTERN in the PMUFW.

When user sets the power-off suspend mode from the Linux user space, Linux will trigger SMC call to ATF to notify that Linux want to enter power-off suspend. So ATF will call set_wakeup_source only for NODE_EXTERN regardless of state of other wakeup sources. The PMUFW will check if NODE_EXTERN is only set for wakeup source then only it will proceed for power-off suspend during suspend procedure.