[PATCH 13/25] OMAP4: PM: Add WakeupGen module as OMAP gic_arch_extn
Tony Lindgren
tony at atomide.com
Wed Sep 14 15:04:33 EDT 2011
* 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?
Regards,
Tony
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