[PATCH RFC 10/11] iommu/arm-smmu-v3: Add IRQ mapping -EPROBE_DEFER handling

[Ashok Raj]

On Fri, Sep 25, 2026 at 09:48:09AM +0200, Lorenzo Pieralisi wrote:
> With the advent of GICv5, IRQs mapping can fail if the interrupt
> controller the wired SMMU interrupts are routed to has not probed
> yet when the SMMU driver probes.
> 
> Handle -EPROBE_DEFER gracefully for IRQ mappings failures.
> 
> Signed-off-by: Lorenzo Pieralisi <lpieralisi at kernel.org>
> Cc: Will Deacon <will at kernel.org>
> Cc: Robin Murphy <robin.murphy at arm.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 5732f3ba0122..1832389916a4 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -5562,18 +5562,26 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>  	/* Interrupt lines */
>  
>  	irq = platform_get_irq_byname_optional(pdev, "combined");
> +	if (irq == -EPROBE_DEFER)
> +		return dev_err_probe(dev, irq, "failed to get combined IRQ\n");
>  	if (irq > 0)
>  		smmu->combined_irq = irq;
>  	else {
>  		irq = platform_get_irq_byname_optional(pdev, "eventq");
> +		if (irq == -EPROBE_DEFER)
> +			return dev_err_probe(dev, irq, "failed to get eventq IRQ\n");
>  		if (irq > 0)
>  			smmu->evtq.q.irq = irq;
>  
>  		irq = platform_get_irq_byname_optional(pdev, "priq");
> +		if (irq == -EPROBE_DEFER)
> +			return dev_err_probe(dev, irq, "failed to get priq IRQ\n");
>  		if (irq > 0)
>  			smmu->priq.q.irq = irq;
>  
>  		irq = platform_get_irq_byname_optional(pdev, "gerror");
> +		if (irq == -EPROBE_DEFER)
> +			return dev_err_probe(dev, irq, "failed to get gerror IRQ\n");
>  		if (irq > 0)
>  			smmu->gerr_irq = irq;
>  	}

minor: 

Maybe consolidate the multiple if (irq == -EPROBE_DEFER) parts and
consolidate the return to one place?


-- 
/ashok.raj
ashok.raj at oss.qualcomm.com
Qualcomm Inc