On Sun, Sep 23 2018 at 03:48 -0600, Marc Zyngier wrote:
On Sat, 22 Sep 2018 18:09:09 +0100,
Lina Iyer <ilina@xxxxxxxxxxxxxx> wrote:
On Sat, Sep 22 2018 at 10:29 -0600, Marc Zyngier wrote:
> Hi Lina,
>
> On Tue, 04 Sep 2018 22:18:08 +0100,
> Lina Iyer <ilina@xxxxxxxxxxxxxx> wrote:
Also, I am exploring an option that was suggested by Stephen [1] to just
use the PDC interrupt as a parent of the GPIO IRQ and use a different
irqchip for the PDC interrupt. I ran into some issue with accessing
irqchip and irqdata of the PDC interrupt, since the irqchip was not in
hierarchy with the GPIO's irqchip. I haven't been able to find time to
resolve the issue that the set_parent_ functions, because of the
hierarchy.
Essentially, we have two different mechanisms for GPIO IRQs based on
whether they can be woken up by the PDC interrupt.
GPIO-IRQ --> PDC --> GIC
GPIO-IRQ --> TLMM SUMMARY --> GIC
Do you think the idea is feasible? It would avoid doing all this
enable/disable at every suspend and even during idle, when the TLMM
could be powered off.
[me tries to page it all in again]
You could have the PDC as part of the GPIO hierarchy:
GPIO -> PDC -> TLMM -> GIC
The PDC irqchip's parent is the GIC as set up in
drivers/irqchip/qcom-pdc.c. Wouldn't that conflict with the established
hierarchy?
and always configure the PDC as a wake-up source. I just wonder if you
can do that without setting up a parallel hierarchy between the PDC
and the GIC. We already have similar things in the tree (see OMAP's
wakeupgen), and it may be worth having a look.
Sure, will take a look.
The lack of interrupt
replaying on the PDC is quite annoying (I have much stronger words in
mind though), and I'm not sure we can easily fix that one without this
parallel interrupt hack (you need something to inject edge interrupts
in the TLMM).
The PDC replays the intterupt at the GIC, not the at the TLMM. So the
hierachy you recommended may not work as well here.
>> + disable_irq(irqd->irq);
>> + enable_irq(irq);
>> + }
>> + }
>
> Given that you're changing in_suspend and parsing the bitmap,
> shouldn't take the pdc spinlock?
>
Since we are the the only CPU running and suspend/resume (and even idle)
would be serialized I didn't see a reason for needing a lock.
In that case, what is the purpose of 'in_suspend' if
msm_gpio_irq_set_wake cannot happen during the suspend/resume phases?
It all seems a bit inconsistent.
Well the disable_irq_wake that I call here, calls into the set_wake
callbacks. Hence the flag to indicate that we should ignore the PDC
interrupt configuration at that time. Let me see if I need to disable
the disable_irq_wake at all.
Thanks,
Lina
