linux-kernel - Re: [PATCH 3/5] irqchip: armada-370-xp: re-enable per-CPU interrupts at resume time

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Date:	Mon, 26 Oct 2015 05:35:46 +0100
From:	Marcin Wojtas <mw@...ihalf.com>
To:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>,
	Lior Amsalem <alior@...vell.com>, Andrew Lunn <andrew@...n.ch>,
	Tawfik Bayouk <tawfik@...vell.com>,
	linux-kernel@...r.kernel.org, Nadav Haklai <nadavh@...vell.com>,
	Gregory Clement <gregory.clement@...e-electrons.com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
Subject: Re: [PATCH 3/5] irqchip: armada-370-xp: re-enable per-CPU interrupts
 at resume time

Thomas,

2015-10-26 1:10 GMT+01:00 Thomas Petazzoni
<thomas.petazzoni@...e-electrons.com>:
> Marcin,
>
> On Sun, 25 Oct 2015 22:22:37 +0100, Marcin Wojtas wrote:
>
>> > @@ -550,16 +572,27 @@ static void armada_370_xp_mpic_resume(void)
>> >                 if (virq == 0)
>> >                         continue;
>> >
>> > -               if (irq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
>> > +               data = irq_get_irq_data(virq);
>> > +
>> > +               if (irq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ) {
>> > +                       /* Non per-CPU interrupts */
>> >                         writel(irq, per_cpu_int_base +
>>
>> For "Non per-CPU interrupts" per_cpu_int_base is used - is it
>> intentional? In armada_370_xp_irq_mask/unmask the condition looks
>> exactly opposite...
>
> Yes, this is normal. Carefully read PATCH 5/5, which adds a big
> comment, which explains the logic of the HW and how the
> irq-armada-370-xp driver copes with it.
>
> Each interrupt can be masked at two levels. One level is enabled when
> the interrupted is mapped, the other upon ->mask()/->unmask(). So
> when we're resuming, we need to re-enable the interrupt at the level it
> was enabled in ->map(), and have ->mask()/->unmask() continue to
> mask/unmask the interrupt at the other level.
>
> For per-CPU interrupts, ->map() and ->resume() enable the interrupt at
> the global level, and leave ->mask()/->unmask() enable/disable at the
> per-CPU level.
>
> For global interrupts, ->map() and ->resume() enable the interrupt at
> the per-CPU level, and leave ->mask()/->unmask() enable/disable at the
> global level.
>
> Again, see PATCH 5/5, and let me know if there are still some unclear
> aspects.
>

Thanks for the explanation - now it's clear.

Btw, I checked the patches with mvneta in both 'standby' and 'mem'
modes on A38x (with not-yet-submitted support for PM in mvneta and
pinctrl) and everything works properly. Hence:

Tested-by: Marcin Wojtas <mw@...ihalf.com>

Best regards,
Marcin
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