Re: [PATCH 09/17] [m68k] IRQ: add handle_polled_irq() for timer basedsoft interrupts

From: Geert Uytterhoeven
Date: Wed Mar 20 2013 - 04:55:07 EST


On Sun, Feb 10, 2013 at 11:36 AM, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> wrote:
> On Thu, Jan 31, 2013 at 1:23 AM, Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
>> [PATCH 09/17] [m68k] IRQ: add handle_polled_irq() for timer based soft interrupts -
>> experimental hack to avoid unhandled interrupt timer to fire
>> on EtherNEC/NetUSBee cards that have no hardware interrupt
>> and need to be polled from a timer
>>
>> This patch adds a special 'polled interrupt' handler for timer based software interrupts.
>
> Adding Thomas and lkml.

No comments/suggestions?
Thanks again!

>> handle_simple_irq() will respond to excessive unhandled interrupts (as are expected for a
>> polling timer interrupt) by disabling the apparently unhandled interrupt source.
>>
>> handle_polled_irq() prevents this by setting the IRQS_POLL_INPROGRESS flag which will cause
>> the unhandled interrupt events to be ignored.
>>
>> This is a temporary hack to allow timer based polling of the Atari ROM port network and USB
>> cards only. Suggestions on how to properly handle this in the normal interrupt framework are
>> most welcome.
>>
>> Signed-off-by: Michael Schmitz <schmitz@xxxxxxxxxx>
>> ---
>> include/linux/irq.h | 1 +
>> kernel/irq/chip.c | 36 ++++++++++++++++++++++++++++++++++++
>> 2 files changed, 37 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/irq.h b/include/linux/irq.h
>> index fdf2c4a..39bfcff 100644
>> --- a/include/linux/irq.h
>> +++ b/include/linux/irq.h
>> @@ -407,6 +407,7 @@ extern void handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc);
>> extern void handle_edge_irq(unsigned int irq, struct irq_desc *desc);
>> extern void handle_edge_eoi_irq(unsigned int irq, struct irq_desc *desc);
>> extern void handle_simple_irq(unsigned int irq, struct irq_desc *desc);
>> +extern void handle_polled_irq(unsigned int irq, struct irq_desc *desc);
>> extern void handle_percpu_irq(unsigned int irq, struct irq_desc *desc);
>> extern void handle_percpu_devid_irq(unsigned int irq, struct irq_desc *desc);
>> extern void handle_bad_irq(unsigned int irq, struct irq_desc *desc);
>> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
>> index 3aca9f2..ae7ef4d 100644
>> --- a/kernel/irq/chip.c
>> +++ b/kernel/irq/chip.c
>> @@ -339,6 +339,42 @@ out_unlock:
>> }
>> EXPORT_SYMBOL_GPL(handle_simple_irq);
>>
>> +/**
>> + * handle_polled_irq - Simple and software-decoded IRQs.
>> + * @irq: the interrupt number
>> + * @desc: the interrupt description structure for this irq
>> + *
>> + * Polled interrupts are sent from a demultiplexing software interrupt
>> + * handler, where no interrupt hardware control is necessary.
>> + */
>> +void
>> +handle_polled_irq(unsigned int irq, struct irq_desc *desc)
>> +{
>> + raw_spin_lock(&desc->lock);
>> +
>> + if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
>> + if (!irq_check_poll(desc))
>> + goto out_unlock;
>> +
>> + desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
>> + kstat_incr_irqs_this_cpu(irq, desc);
>> +
>> + if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
>> + desc->istate |= IRQS_PENDING;
>> + goto out_unlock;
>> + }
>> +
>> + desc->istate |= IRQS_POLL_INPROGRESS;
>> +
>> + handle_irq_event(desc);
>> +
>> + desc->istate &= ~(IRQS_POLL_INPROGRESS);
>> +
>> +out_unlock:
>> + raw_spin_unlock(&desc->lock);
>> +}
>> +EXPORT_SYMBOL_GPL(handle_polled_irq);
>> +
>> /*
>> * Called unconditionally from handle_level_irq() and only for oneshot
>> * interrupts from handle_fasteoi_irq()
>> --
>> 1.7.0.4

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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