linux-kernel - Re: [PATCH 09/17] [m68k] IRQ: add handle_polled

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Message-ID: <CAMuHMdXB1LNGXkz=_eCQ+i+tu18ffbCA9dP_LRrF1CUBv-q-uQ@mail.gmail.com>
Date:	Wed, 20 Mar 2013 09:54:56 +0100
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Michael Schmitz <schmitzmic@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>
Cc:	linux-m68k@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/17] [m68k] IRQ: add handle_polled_irq() for timer based
 soft interrupts

On Sun, Feb 10, 2013 at 11:36 AM, Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> On Thu, Jan 31, 2013 at 1:23 AM, Michael Schmitz <schmitzmic@...il.com> 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@...ian.org>
>> ---
>>  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@...ux-m68k.org

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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