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Message-ID: <1393955639.661016045@f378.i.mail.ru>
Date: Tue, 04 Mar 2014 21:53:59 +0400
From: Alexander Shiyan <shc_work@...l.ru>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org,
Mark Brown <broonie@...nel.org>,
Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH] irq: Export symbol no_action()
+сс Arnd Bergmann
Вторник, 4 марта 2014, 16:46 +01:00 от Thomas Gleixner <tglx@...utronix.de>:
> On Tue, 4 Mar 2014, Alexander Shiyan wrote:
>
> > Вторник, 4 марта 2014, 12:05 +01:00 от Thomas Gleixner <tglx@...utronix.de>:
> > > On Sat, 1 Mar 2014, Alexander Shiyan wrote:
> > >
> > > > This will allow to use dummy IRQ handler no_action() from
> > > > drivers compiled as module. For example, dummy handler is could
> > > > be used for drivers that use ARM FIQ interrupts.
> > >
> > > And why exactly requires a driver which uses ARM FIQ interrupts the
> > > no_action implementation?
> >
>
> > FIQ Interrupt handler is not used in this function. In FIQ case this
> > is just a dummy declaration. Real handler is assigned by using the
> > set_fiq_handler().
>
> Why do you need a dummy declaration at all?
>
> set_fiq_handler() is completely detached from the generic interrupt
> subsystem.
Some limitations of hardware, such as bit interleaving for normal and
FIQ interrupts for mask/status registers, led to the implement single
driver for interrupt handling.
As a result, all interrupts can be described equally, and single mechanism
is used for the request/free and enable/disable.
Correct me if I'm wrong. Driver that implements it, resent several times
and expect comments within 3 months [1], you are the only one person,
Thomas, specified as maintainer for this subsystem.
I repeat, if I'm wrong in the implementation, let's fix this.
[1]: http://marc.info/?l=linux-arm-kernel&m=139132855024699
Thanks.
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