Abstract: Systems and methods for external access detection and recovery in a subsystem of a system-on-a-chip (SoC) in a portable computing device (PCD) are presented. In operation, a subsystem of the SoC is operated in an internal mode independently of the SoC while the SoC is in a low power state, such as a non-functional or zero power state or mode. The subsystem comprises a processor in communication with a memory, a sensor, and a monitor module. The monitor module detects when the processor of the subsystem requests access to a component external to the subsystem. In response to this detected request, the SoC is caused to enter into a full power state or mode, and the subsystem is caused to exit the internal mode of operation.

Abstract: Systems and methods for external access detection and recovery in a subsystem of a system-on-a-chip (SoC) in a portable computing device (PCD) are presented. In operation, a subsystem of the SoC is operated in an internal mode independently of the SoC while the SoC is in a low power state, such as a non-functional or zero power state or mode. The subsystem comprises a processor in communication with a memory, a sensor, and a monitor module. The monitor module detects when the processor of the subsystem requests access to a component external to the subsystem. In response to this detected request, the SoC is caused to enter into a full power state or mode, and the subsystem is caused to exit the internal mode of operation.

Abstract: Various embodiments of methods and systems for hardware-based memory power management (“HMPM”) in a portable computing device (“PCD”) running secure and non-secure execution environments are disclosed. Hardware-based state machines are uniquely associated with, and under the control of, the non-secure execution environment, the secure execution environment and a virtual manager, respectively. The states of the state machines constitute votes by each of the execution environments and the virtual manager to control the power supply state to the memory component, such as a cache memory. The votes are monitored by a digital circuit that, based on a combination logic of the votes, generates an output signal to trigger a power management component to maintain, supply or remove power on a rail associated with the memory component. In this way, the power supply state to the memory component cannot be unilaterally changed by an application running in the non-secure execution environment.