Sergei Shtylyov wrote:
>
> Hello.
>
Hi ;-)
> On 28-09-2010 5:31, Kukjin Kim wrote:
>
> > From: Changhwan Youn<chaos.youn@xxxxxxxxxxx>
>
> > It is reported by Junseok Jung that using clz instruction is
> > better instead of using for-loop to find the interrupt source.
> > This patch modifies interrupt source searching code using __fls().
> > The __fls() is implemented using clz instruction.
>
> > Suggested-by: Junseok Jung<jundols.jung@xxxxxxxxxxx>
> > Signed-off-by: Changhwan Youn<chaos.youn@xxxxxxxxxxx>
> > Signed-off-by: Kukjin Kim<kgene.kim@xxxxxxxxxxx>
> > ---
> > arch/arm/mach-s5pv310/irq-combiner.c | 6 +-----
> > 1 files changed, 1 insertions(+), 5 deletions(-)
>
> > diff --git a/arch/arm/mach-s5pv310/irq-combiner.c
b/arch/arm/mach-s5pv310/irq-
> combiner.c
> > index 0f70521..39e3647 100644
> > --- a/arch/arm/mach-s5pv310/irq-combiner.c
> > +++ b/arch/arm/mach-s5pv310/irq-combiner.c
> > @@ -66,11 +66,7 @@ static void combiner_handle_cascade_irq(unsigned int
irq,
> struct irq_desc *desc)
> > if (status == 0)
> > goto out;
> >
> > - for (combiner_irq = 0; combiner_irq< 32; combiner_irq++) {
> > - if (status & 0x1)
> > - break;
> > - status>>= 1;
> > - }
> > + combiner_irq = __fls(status);
>
> But the loop finds the *first* set bit, not the last...
>
Yes, you're right.
So I already re-submitted like following :-)
http://lists.infradead.org/pipermail/linux-arm-kernel/2010-September/027071.
html
Thanks for your pointing out.
Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@xxxxxxxxxxx>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.
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