Re: regression in irq sharing caused by genirq: Use irqd_get_trigger_type to compare the trigger type for shared IRQs

[Petr Cvek]

Dne 8.11.2017 v 14:11 Marc Zyngier napsal(a):
> On 08/11/17 13:09, Marc Zyngier wrote:
> > On 07/11/17 23:41, Petr Cvek wrote:
> > > Hello,
> > >
> > > Commit 382bd4de61827 ("genirq: Use irqd_get_trigger_type to compare the
> > > trigger type for shared IRQs") causes a regression for pda-power driver
> > > and Magician machine (mach-pxa/magician.c).
> > >
> > >     unsigned int oldtype = irqd_get_trigger_type(&desc->irq_data);
> > >
> > >     ... assert:
> > > 	oldtype == 0	//new code
> > > 	old->flags == 0x83	//old code
> > > 	new->flags & IRQF_TRIGGER_MASK == 3
> > >
> > >     if (!((old->flags & new->flags) & IRQF_SHARED) ||
> > > 	(oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
> > > 	((old->flags ^ new->flags) & IRQF_ONESHOT))
> > > 		goto mismatch;
> > >
> > > The assert shows the new code will trigger the jump for "mismatch" error
> > > the old variant of code works fine.
> > >
> > > The case for Magician machine is specific as the same interrupt line is
> > > requested twice from the same driver (pda-power). But it still could
> > > point to some hidden problem in the IRQ setup code.
> > >
> > > I wasn't able to trace the code when desc->irq_data is getting set. The
> > > flags values should be (as with old->flags):
> > >
> > > 	IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING
> > >
> > > It could be a problem with a weird IRQ sharing in magician code, but
> > > it's still failing the driver and the start of the charging system.
> > >
> > > IRQ definition in arch/arm/mach-pxa/magician.c looks like this:
> > >
> > > static struct resource power_supply_resources[] = {
> > > 	[0] = {
> > > 		.name	= "ac",
> > > 		.flags	= IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHEDGE |
> > > 			IORESOURCE_IRQ_LOWEDGE,
> > > 		.start	= IRQ_MAGICIAN_VBUS,
> > > 		.end	= IRQ_MAGICIAN_VBUS,
> > > 	},
> > > 	[1] = {
> > > 		.name	= "usb",
> > > 		.flags	= IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHEDGE |
> > > 			IORESOURCE_IRQ_LOWEDGE,
> > > 		.start	= IRQ_MAGICIAN_VBUS,
> > > 		.end	= IRQ_MAGICIAN_VBUS,
> > > 	},
> > > };
> > >
> > > and IRQ requests from drivers/power/supply/pda_power.c look like this:
> > >
> > > if (ac_irq) {
> > > 	ret = request_irq(ac_irq->start, power_changed_isr,
> > > 			  get_irq_flags(ac_irq), ac_irq->name,
> > > 			  pda_psy_ac);
> > > ...
> > > if (usb_irq) {
> > > 	ret = request_irq(usb_irq->start, power_changed_isr,
> > > 			  get_irq_flags(usb_irq),
> > > 			  usb_irq->name, pda_psy_usb);
> > >
> > > I could rewrite the part in the magician code so it would use only one
> > > interrupt, but it doesn't solve why oldtype == 0 problem.
> >
> > Yeah, this is a pretty ugly corner case that crops up because we more
> > and more assume things like DT, which is going to configure the expected
> > trigger type ahead of the interrupt being requested... Of course, PXA is
> > not converted to DT, and unlikely to ever be.
> >
> > Could you please give the following hack a go and let us know if it
> > solves your problem? If it does, I'll think of a more generic solution.

Hi,
yeah it works now and the assert is oldtype == 3 and old->flags == 3 so 
neither versions of condition won't trigger goto mismatch.

> > Thanks,
> >
> > 	M.
> >
> > diff --git a/drivers/power/supply/pda_power.c b/drivers/power/supply/pda_power.c
> > index 922a86787c5c..a32ae240ef7d 100644
> > --- a/drivers/power/supply/pda_power.c
> > +++ b/drivers/power/supply/pda_power.c
> > @@ -24,7 +24,15 @@
> >   
> >   static inline unsigned int get_irq_flags(struct resource *res)
> >   {
> > -	return IRQF_SHARED | (res->flags & IRQF_TRIGGER_MASK);
> > +	struct irq_data *d = irq_get_irq_data(res->start);
> > +	unsigned int trig = res->flags & IRQF_TRIGGER_MASK;
> > +
> > +	BUG_ON(!d);
> > +
> > +	if (!irqd_get_trigger_type(d))
> > +		irqd_set_trigger_type(trig);
>
> Of course, this should be
>
> 		irqd_set_trigger_type(d, trig);

and (in case anyone other want to try)
#include <linux/irq.h>

> > +
> > +	return IRQF_SHARED | trig;
> >   }
> >   
> >   static struct device *dev;
>
> 	M.

cheers,
Petr