Method of DVFS-power management and corresponding system

A method for managing a dynamic voltage and frequency scaling (DVFS) power supply, the method comprising:

• generating, by a secure environment, a secure instruction defining a plurality of permitted operating points, each of the plurality of permitted operating points comprising a different combination of voltage and frequency for the DVFS power supply, the plurality of permitted operating points together defining an upper frequency limit for a given voltage beyond which the secure environment becomes dysfunctional;
• generating, by a non-secure environment, a request to modify the DVFS power supply, the request to modify comprising a voltage-frequency operating point, the voltage-frequency operating point comprising a voltage and a frequency for operating the secure environment;
• scaling the DVFS power supply to an operating point below the upper frequency limit, in response to the request to modify the DVFS power supply and in response to determining that the voltage-frequency operating point in the request is above the upper frequency limit;
• and
• operating the secure environment at the operating point below the upper frequency limit.

A system on chip comprising:

• a dynamic voltage and frequency scaling (DVFS) power supply;
• a secure environment configured to generate a secure instruction defining a permitted operating point of voltage and frequency for the DVFS power supply and assign a label for the permitted operating point;
• a non-secure environment configured to generate a request to modify the DVFS power supply, the request to modify comprising a voltage-frequency operating point;
• and
• a power supply management control module configured to scale the DVFS power supply to the permitted operating point, in response to the request to modify the DVFS power supply and in response to determining that the request to modify includes the label of the permitted operating point.

An electronic apparatus comprising:

• a system on chip comprising
• a dynamic voltage and frequency scaling (DVFS) power supply,
• a secure environment configured to generate a secure instruction defining a permitted operating point of voltage and frequency for the DVFS power supply and assign a label for the permitted operating point,
• a non-secure environment configured to generate a request to modify the DVFS power supply, the request to modify comprising a voltage-frequency operating point, and
• a power supply management control module configured to scale the DVFS power supply to the permitted operating point, in response to the request to modify the DVFS power supply and in response to determining that the request to modify includes the label of the permitted operating point;
• and
• a voltage supply device configured to supply a power supply voltage controlled by the power supply management control module.