Re: [PATCH v4 2/3] irqchip/loongson-eiointc: Skip handling if there is no pending irq

[maobibo]

On 2024/1/29 下午8:27, Huacai Chen wrote:
> Hi, Bibo,
>
> As commented in another patch, you can use eiointc_irq_dispatch(),
> iocsr_read64() to describe functions, and it is better to use
> Loongson-3A5000, Loongson-2K2000, Loongson-2K0500 rather than 3A5000,
> 2K2000, 2K0500. Besides, please always use IRQs rather than IRQS.
Huacai,

Thanks for reviewing.

Will do in next patch.

Regards
Bibo Mao
> With these modifications,
>
> Acked-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
>
> On Thu, Jan 25, 2024 at 7:36 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> > It is one simple optimization in the interrupt dispatch function
> > eiointc_irq_dispatch. There are 256 IRQs supported for eiointc on
> > 3A5000 and 2K2000 platform, 128 IRQS on 2K0500 platform, eiointc irq
> > handler reads the bitmap and find pending irqs when irq happens. So
> > there are several consecutive iocsr_read64 operations for the all
> > bits to find all pending irqs. If the pending bitmap is zero, it
> > means that there is no pending irq for the this irq bitmap range,
> > we can skip handling to avoid some useless operations such as
> > clearing hw ISR.
> >
> > Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> > ---
> >   drivers/irqchip/irq-loongson-eiointc.c | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
> > index b3736bdd4b9f..6a71a8c29ac7 100644
> > --- a/drivers/irqchip/irq-loongson-eiointc.c
> > +++ b/drivers/irqchip/irq-loongson-eiointc.c
> > @@ -198,6 +198,12 @@ static void eiointc_irq_dispatch(struct irq_desc *desc)
> >
> >          for (i = 0; i < eiointc_priv[0]->vec_count / VEC_COUNT_PER_REG; i++) {
> >                  pending = iocsr_read64(EIOINTC_REG_ISR + (i << 3));
> > +
> > +               /* Skip handling if pending bitmap is zero */
> > +               if (!pending)
> > +                       continue;
> > +
> > +               /* Clear the IRQs */
> >                  iocsr_write64(pending, EIOINTC_REG_ISR + (i << 3));
> >                  while (pending) {
> >                          int bit = __ffs(pending);
> > --
> > 2.39.3