Re: [PATCH] irqchip/apple-aic: Only handle PMC interrupt as FIQ when configured to fire FIQ

["Sven Peter" <sven@svenpeter.dev>]

Hi,


On Fri, Jan 17, 2025, at 18:02, Nick Chan wrote:
> The CPU PMU in Apple SoCs can be configured to fire its interrupt in one
> of several ways, and since Apple A11 one of the method is FIQ. Only handle
> the PMC interrupt as a FIQ when the CPU PMU has been configured to fire
> FIQs.
>
> Cc: stable@vger.kernel.org
> Fixes: c7708816c944 ("irqchip/apple-aic: Wire PMU interrupts")
> Signed-off-by: Nick Chan <towinchenmi@gmail.com>
> ---
>  drivers/irqchip/irq-apple-aic.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-apple-aic.c 
> b/drivers/irqchip/irq-apple-aic.c
> index da5250f0155c..c3d435103d6d 100644
> --- a/drivers/irqchip/irq-apple-aic.c
> +++ b/drivers/irqchip/irq-apple-aic.c
> @@ -577,7 +577,8 @@ static void __exception_irq_entry 
> aic_handle_fiq(struct pt_regs *regs)
>  						  AIC_FIQ_HWIRQ(AIC_TMR_EL02_VIRT));
>  	}
> 
> -	if (read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & PMCR0_IACT) {
> +	if (read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) &
> +	    (FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_FIQ) | PMCR0_IACT)) {

That's a somewhat unusual way to use FIELD_PREP and I'm not sure the
expression even does what you want. It's true when only PMCR0_IACT is set and
your commit description mentions that you only when to handle these when
FIQ have been configured. Am I missing something here?


Best,


Sven