Re: [PATCH] irqchip/atmel-aic5: handle suspend to RAM

From: Alexandre Belloni
Date: Mon Apr 10 2017 - 08:31:14 EST


On 09/04/2017 at 13:13:33 +0100, Marc Zyngier wrote:
> On Thu, 6 Apr 2017 18:17:53 +0200
> Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On sama5d2, VDD core may be cut while suspending to RAM. This means the
> > AIC5 registers content is lost. Restore it at resume time.
> >
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/irqchip/irq-atmel-aic5.c | 17 +++++++++++++++--
> > 1 file changed, 15 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/irqchip/irq-atmel-aic5.c b/drivers/irqchip/irq-atmel-aic5.c
> > index 2a624d87a035..ddbf60251b0e 100644
> > --- a/drivers/irqchip/irq-atmel-aic5.c
> > +++ b/drivers/irqchip/irq-atmel-aic5.c
> > @@ -150,6 +150,8 @@ static int aic5_set_type(struct irq_data *d, unsigned type)
> > }
> >
> > #ifdef CONFIG_PM
> > +u32 smr_cache[128];
>
> Two things:
>
> - Why isn't this array static?
> - Why is the size hard-coded to 128, while the loops below are based on
> the domain revmap_size.
>
> > +
> > static void aic5_suspend(struct irq_data *d)
> > {
> > struct irq_domain *domain = d->domain;
> > @@ -159,6 +161,11 @@ static void aic5_suspend(struct irq_data *d)
> > int i;
> > u32 mask;
> >
> > + for (i = 0; i < domain->revmap_size; i++) {
> > + irq_reg_writel(bgc, i, AT91_AIC5_SSR);
> > + smr_cache[i] = irq_reg_readl(bgc, AT91_AIC5_SMR);
> > + }
> > +
>
> This seem to affect more than just the sama5d2 part. Is that expected?
>

I'll send v2 addressing your comments shortly. The answer is that it
works on all the SoCs. It was simply not needed before. I'll try to come
up with a solution only affecting sama5d2 anyway.

The best would be to be able to know whether will be cut or not but it
is not currently possible with the PM core.


--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com