os/arch/arm/src/armv7-a: Update hotplug logic for PM + SMP

Samsung / TizenRT

TizenRT is a lightweight RTOS-based platform to support low-end IoT devices

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os/arch/arm/src/armv7-a: Update hotplug logic for PM + SMP #6256

Closed edwakuwaku closed 1 month ago

edwakuwaku commented 3 months ago

When the secondary core is not in idle thread and system went into sleep, we faced some unexpected behaviour during system wakeup (ie. crash)
Thus, this PR added a check to the hotplug handler, to determine whether the secondary core is already in idle thread and ready for shutdown
If the secondary core is still running, the primary core will restore it's irq, so that it will be able to react to some task/scheduler change which is requested by secondary core (ie. pause request)

edwakuwaku commented 3 months ago

Hi @ewoodev @kishore-sn @ritesh55555 , let's discuss about the PM + SMP sleep/wakeup operation in this PR.

edwakuwaku commented 3 months ago

Hello @kishore-sn @ewoodev @ritesh55555 , I have pushed the latest implementation. Instead of pause/resume, I changed to use gating as I think this method is not affecting the task/scheduler block. When I tested with pause/resume, there is some deadlock happening after secondary core is paused. Thus, I think there are still some misunderstanding from our side regarding the usage of cpu pause/resume. I tested this changes with both cores in idle thread, it works fine as previously. Please help to test this changes on the condition of "cpu0: idle thread, cpu1: not idle thread". The sleep should be aborted under this condition.

edwakuwaku commented 3 months ago

@ritesh55555 @kishore-sn , Could you please test with this PR on internal branch and leave the test results here? Thanks.

gSahitya-samsung commented 2 months ago

@edwakuwaku Please check merge conflicts

ritesh55555 commented 2 months ago

@ritesh55555 @kishore-sn , Could you please test with this PR on internal branch and leave the test results here? Thanks.

hi @edwakuwaku , Can you please rebase the PR, when i merge and test i am getting stuck just after booting several times. May be if you merge yourself and update, it would be better to test?

edwakuwaku commented 2 months ago

I have rebased to latest master.

ritesh55555 commented 2 months ago

This PR is working fine with product code. There is no more hang issue during sleep and wakeup. It is working fine

gSahitya-samsung commented 2 months ago

Can we keep SMP Hotplug logic outside pm_idle by creating new APIs ?

edwakuwaku commented 2 months ago

Can we keep SMP Hotplug logic outside pm_idle by creating new APIs ?

I have talked with @ritesh55555 about this, after this PR is merged, cleanup can be done from Samsung team on PM + SMP which you think it is necessary.