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The current implementation only saves and restores the context for ETM sources while ignoring the context of links. However, if funnels or replicators on a linked path resides in a CPU or cluster power domain, the hardware context for the link will be lost after resuming from low power states. To support context management for links during CPU low power modes, a better way is to implement CPU PM callbacks in the Arm CoreSight core layer. As the core layer has sufficient information for linked paths, from tracers to links, which can be used for power management. As a first step, this patch registers CPU PM notifier in the core layer. If a source device provides callbacks for saving and restoring context, these callbacks will be invoked in CPU suspend and resume. Reviewed-by: James Clark <james.clark@linaro.org> Tested-by: James Clark <james.clark@linaro.org> Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com> Tested-by: Jie Gan <jie.gan@oss.qualcomm.com> Signed-off-by: Leo Yan <leo.yan@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-11-f88c4a3ecfe9@arm.com