/**
*
* @brief Power management policy when kernel begins idling
*
* This routine implements the power management policy based on the time
* until the timer expires, in system ticks.
* Routine is invoked from the idle task with interrupts disabled
*
* @return N/A
*/
void _sys_power_save_idle(int32_t ticks)
{
#if defined(CONFIG_TICKLESS_IDLE)
if ((ticks == TICKS_UNLIMITED) || ticks >= _sys_idle_threshold_ticks) {
/*
* Stop generating system timer interrupts until it's time for
* the next scheduled microkernel timer to expire.
*/
_timer_idle_enter(ticks);
}
#endif /* CONFIG_TICKLESS_IDLE */
nano_cpu_set_idle(ticks);
#if (defined(CONFIG_SYS_POWER_LOW_POWER_STATE) || \
defined(CONFIG_SYS_POWER_DEEP_SLEEP) || \
defined(CONFIG_DEVICE_POWER_MANAGEMENT))
/*
* Call the suspend hook function, which checks if the system should
* enter deep sleep, low power state or only suspend devices.
* If the time available is too short for any PM operation then
* the function returns SYS_PM_NOT_HANDLED immediately and kernel
* does normal idle processing. Otherwise it will return the code
* corresponding to the action taken.
*
* This function can just suspend devices without entering
* deep sleep or cpu low power state. In this case it should return
* SYS_PM_DEVICE_SUSPEND_ONLY and kernel would do normal idle
* processing.
*
* This function is entered with interrupts disabled. If the function
* returns either SYS_PM_LOW_POWER_STATE or SYS_PM_DEEP_SLEEP then
* it should ensure interrupts are re-enabled before returning.
* This is because the kernel does not do its own idle processing in
* these cases i.e. skips nano_cpu_idle(). The kernel's idle
* processing re-enables interrupts which is essential for kernel's
* scheduling logic.
*/
if (!(_sys_soc_suspend(ticks) &
(SYS_PM_DEEP_SLEEP | SYS_PM_LOW_POWER_STATE))) {
nano_cpu_idle();
}
#else
nano_cpu_idle();
#endif
}
static void _sys_power_save_idle(int32_t ticks __unused)
{
#if defined(CONFIG_TICKLESS_IDLE)
if ((ticks == K_FOREVER) || ticks >= _sys_idle_threshold_ticks) {
/*
* Stop generating system timer interrupts until it's time for
* the next scheduled kernel timer to expire.
*/
_timer_idle_enter(ticks);
}
#endif /* CONFIG_TICKLESS_IDLE */
set_kernel_idle_time_in_ticks(ticks);
#if (defined(CONFIG_SYS_POWER_LOW_POWER_STATE) || \
defined(CONFIG_SYS_POWER_DEEP_SLEEP))
_sys_pm_idle_exit_notify = 1;
/*
* Call the suspend hook function of the soc interface to allow
* entry into a low power state. The function returns
* SYS_PM_NOT_HANDLED if low power state was not entered, in which
* case, kernel does normal idle processing.
*
* This function is entered with interrupts disabled. If a low power
* state was entered, then the hook function should enable inerrupts
* before exiting. This is because the kernel does not do its own idle
* processing in those cases i.e. skips k_cpu_idle(). The kernel's
* idle processing re-enables interrupts which is essential for
* the kernel's scheduling logic.
*/
if (_sys_soc_suspend(ticks) == SYS_PM_NOT_HANDLED) {
_sys_pm_idle_exit_notify = 0;
k_cpu_idle();
}
#else
k_cpu_idle();
#endif
}