Messages in this thread | | | Date | Thu, 13 Mar 2014 16:13:22 +0100 | From | Hans de Goede <> | Subject | Re: [PATCH v2 4/4] irqchip: sun4i: Use handle_fasteoi_late_irq for the ENMI (irq 0) |
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Hi,
On 03/13/2014 03:46 PM, Thomas Gleixner wrote: > On Wed, 12 Mar 2014, Hans de Goede wrote: > >> The ENMI needs to have the ack done *after* clearing the interrupt source, >> otherwise we will get a spurious interrupt for each real interrupt. Switch >> to the new handle_fasteoi_late_irq handler which gives us the desired behavior. >> >> Signed-off-by: Hans de Goede <hdegoede@redhat.com> >> --- >> drivers/irqchip/irq-sun4i.c | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c >> index 8a2fbee..4b1c874 100644 >> --- a/drivers/irqchip/irq-sun4i.c >> +++ b/drivers/irqchip/irq-sun4i.c >> @@ -77,15 +77,22 @@ static void sun4i_irq_unmask(struct irq_data *irqd) >> static struct irq_chip sun4i_irq_chip = { >> .name = "sun4i_irq", >> .irq_ack = sun4i_irq_ack, >> + .irq_eoi = sun4i_irq_ack, /* For the ENMI */ >> .irq_mask = sun4i_irq_mask, >> .irq_unmask = sun4i_irq_unmask, >> + .flags = IRQCHIP_EOI_THREADED, /* Only affects the ENMI */ > > That's not really true. The flags affect all interrupts which share > that chip.
Yep, I figured out as much myself too while thinking a bit more about this this morning.
So what I'm going to do in my next version of this patch is use 2 irqchip structures for the sun4i irqchip, one to describe the special IRQ 0 and for all the others.
> >> }; >> >> static int sun4i_irq_map(struct irq_domain *d, unsigned int virq, >> irq_hw_number_t hw) >> { >> - irq_set_chip_and_handler(virq, &sun4i_irq_chip, >> - handle_level_irq); >> + if (hw == 0) /* IRQ 0, the ENMI needs special handling */ >> + irq_set_chip_and_handler(virq, &sun4i_irq_chip, >> + handle_fasteoi_late_irq); >> + else >> + irq_set_chip_and_handler(virq, &sun4i_irq_chip, >> + handle_level_irq); > > I wonder what happens when you use the fasteoi handler for all of > them.
As mentioned in my previous mail doing an ack (or an eio) seems to be unnecessary for all but IRQ 0.
I do wonder if handle_level_irq is the right handle*irq function to use in this case, since this is strictly used in the non smp case I think that the mask / unmask done by handle_level_irq is not necessary for non threaded handlers. So what would be the correct handle*irq function to use in this case ?
Note the irqs are level irqs. IOW they may stay asserted while the handler runs because of the handler and a new irq raising.
Regards,
Hans
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