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@xxxxxxxxxx>
>> ---
>> 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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