Adds in power management for CPU bound CTI devices: i) CPU Hotplug - registers a new notifier for CPU start and stop events. ii) CPU idle PM event notifier to handle PM_ENTER, PM_ENTER_FAILED and PM_EXIT events.
Tested with DB410c on coresight/next tree (Linux 5.7-rc1)
Changes since v2: 1) removed helper functions filtering on CONFIG_CPU_PM to call cpu_pm fns directly. 2) add check for return value from cpuhp_remove_state_nocalls().
Changes since V1: (requested by Mathieu). 1) Split into separate patches for CPU pm and CPU hotplug handling. 2) Enable on hotplug has a specific function to enable the hardware, while leaving the enable reference counts unchanged.
Mike Leach (2): coresight: cti: Add CPU Hotplug handling to CTI driver. coresight: cti: Add CPU idle pm notifer to CTI devices.
drivers/hwtracing/coresight/coresight-cti.c | 160 ++++++++++++++++++++ include/linux/cpuhotplug.h | 1 + 2 files changed, 161 insertions(+)