AI Engine Clock Frequency Scaling - 2023.2 English

Versal Adaptive SoC System Software Developers Guide (UG1304)

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2023.2 English

When a subsystem is using an AI Engine partition, it may request to increase or decrease the AI Engine clock frequency. The subsystem can use XPm_SetRequirement to change the clock frequency. The QoS argument is used to represent the divider value.

The following example call requests that the AI Engine clock divider be set to four:

XPm_SetRequirement(aie_node, PM_CAP_ACCESS, 4, REQUEST_ACK_NO)

The call to change the frequency is considered only a request and is fulfilled if no other AI Engine partitions are using a frequency higher than the requested divider value. The highest requested frequency from any subsystem for an AI Engine is fulfilled.

  • If the subsystem does not care what divider value is used, the QoS can be set to 0.
  • If the subsystem would like to reset to the original boot time divider value, the QoS can be set to 1.

Any QoS value that is less than the default divider value (boot time) resets the divider value to the default.