Re: [PATCH v3 22/26] irqchip/apple-aic: Drop support for custom PMU irq partitions

Marc Zyngier
2025-09-22T20:24:46Z

On Mon, 22 Sep 2025 19:43:40 +0100,
Sven Peter <sven@kernel.org> wrote:
>
> On 22.09.25 10:28, Marc Zyngier wrote:
> > Similarly to what has been done for GICv3, drop the irq partitioning
> > support from the AIC driver, effectively merging the two per-cpu
> > interrupts for the PMU.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
>
> Reviewed-by: Sven Peter <sven@kernel.org>
>
>
> > drivers/irqchip/irq-apple-aic.c | 28 +++++++---------------------
> > 1 file changed, 7 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
> > index cb8b6f40ce8d3..6305d25b9e77b 100644
> > --- a/drivers/irqchip/irq-apple-aic.c
> > +++ b/drivers/irqchip/irq-apple-aic.c
> > @@ -578,16 +578,9 @@ static void __exception_irq_entry aic_handle_fiq(struct pt_regs *regs)
> > }
> > if ((read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & (PMCR0_IMODE |
> > PMCR0_IACT)) ==
> > - (FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_FIQ) | PMCR0_IACT)) {
> > - int irq;
> > - if (cpumask_test_cpu(smp_processor_id(),
> > - &aic_irqc->fiq_aff[AIC_CPU_PMU_P]->aff))
> > - irq = AIC_CPU_PMU_P;
> > - else
> > - irq = AIC_CPU_PMU_E;
> > + (FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_FIQ) | PMCR0_IACT))
> > generic_handle_domain_irq(aic_irqc->hw_domain,
> > - AIC_FIQ_HWIRQ(irq));
> > - }
> > + AIC_FIQ_HWIRQ(AIC_CPU_PMU_P));
>
> Probably one of the most confusing diffs for a change that's actually
> fairly simple that the diff algorithm generated! I was only able to
> tell what's going on by looking at the file after applying this.

It appears that all 4 algorithms (myers, minimal, patience and
histogram) give the exact same resolution for these two hunks.

It would have been easier to read if I had rewritten the 'if'
statement to be on a single line (and moved the whole field business
to a helper), but I went for the smallest possible change. My bad,

Thanks for the review!

M.

--
Jazz isn't dead. It just smells funny.