Hi, this is Scaria Kochidanadu, from Texas Instruments and would like to present : "s2idle-driven Low Power Mode Selection using PSCI on AM62L", in the TF-A tech forum on April 2nd, 2026.
We present a runtime-configurable low power mode(LPM) management approach for *PSCI* firmware in ATF, implemented on the AM62L SoC, a 2-core system with A53 cores. The primary goal of this session is to gather feedback on the *suitability of this design for upstreaming*, and to get guidance on key challenges encountered during implementation before proceeding with further debugging and optimization. In this design, we transition to an *s2idle-based flow* where Linux cpuidle framework and governor drive idle state selection, from the multiple platform-specific standby and low power modes that are provided in the devicetree. The PSCI driver in ATF is then responsible for the validation of the idle-states passed and the entire suspend-resume flow, with the *Operating-System Initiated (OSI) mode in PSCI*. As ATF now handles the full suspend-resume flow, it has the responsibility of managing the powering down and bringing up of the cores, along with the state of the system. We observe issues related to core *coordination in a multi-core system*, as well as system state management during resume, including *GIC* and (*Interrupt Translation Service*)ITS context handling. In this session, we will present our suspend and resume design in the AM62L PSCI implementation and discuss these challenges in detail. We would also like to discuss the *current validation logic* for the context-preserving retention states like standby and our approach to enable standby mode. We are particularly interested in feedback on whether this *OS-driven LPM selection model aligns with ATF design expectations*, and on recommended approaches for handling *inter-core coordination and system state restoration within PSCI-based flows*. Regards, Scaria Kochidanadu, Texas Instruments.