[PATCH 13/25] OMAP4: PM: Add WakeupGen module as OMAP gic_arch_extn
santosh.shilimkar at ti.com
Wed Sep 14 22:57:48 EDT 2011
On Thursday 15 September 2011 12:34 AM, Tony Lindgren wrote:
> * Santosh <santosh.shilimkar at ti.com> [110914 09:49]:
>> On Wednesday 14 September 2011 10:48 PM, Tony Lindgren wrote:
>>> * Santosh<santosh.shilimkar at ti.com> [110914 09:40]:
>>>> On Wednesday 14 September 2011 10:38 PM, Tony Lindgren wrote:
>>>>> * Santosh<santosh.shilimkar at ti.com> [110914 09:16]:
>>>>> Thanks for the clarification. It seems to me the spec is most likely
>>>>> wrong as we've had the GIC working for over two years now without
>>>>> doing anything with the wakeup gen registers :)
>>>> It's working because CPU clockdomain are never put under HW
>>>> supervised mode and they are kept in force wakeup. Clock-domain
>>>> never idles on mainline code. PM series will put the clock-domains
>>>> under HW supervison as needed to achieve any low power states and
>>>> then all sorts of corner cases will come out.
>>> But again the wakeup gen triggers only do something when hitting
>>> idle. There should be no use for them during runtime, right?
>> You missed my point in the description. Clockdomain inactive
>> doesn't depend on idle or WFI execution. Under HW supervison
>> CPU clock domain can get into inactive when CPU is stalled and
>> waiting for a read response from slow interconnect.
> Ah OK. If it's needed during runtime too then that explains why
> the registers need to be kept in sync.
>> One thing for sure. Designers has chosen a wrong name to this
>> IP. Wakeugen apears like needed only for low power wakeup which
>> not seems to be entirely correct as per specs
> Yes it's not obvious reading the TRM either. Maybe add some
> comment about that to the patch?
You are right. Documentation isn't clear about this. Will
add the above point in change log.
btw, thanks for the good discussion on this topic.
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