Re: [PATCH 1/2] iommu/arm-smmu-v3: Don't display an error when IRQ lines are missing

From: John Garry <john.garry@huawei.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<iommu@lists.linux-foundation.org>
Cc: will@kernel.org, robin.murphy@arm.com
Subject: Re: [PATCH 1/2] iommu/arm-smmu-v3: Don't display an error when IRQ lines are missing
Date: Mon, 11 Nov 2019 11:52:38 +0000	[thread overview]
Message-ID: <d0dfd82d-dcec-010c-6a69-c8f2b15f5c7a@huawei.com> (raw)
In-Reply-To: <20191111111721.4145919-1-jean-philippe@linaro.org>

On 11/11/2019 11:17, Jean-Philippe Brucker wrote:
> Since commit 7723f4c5ecdb ("driver core: platform: Add an error message
> to platform_get_irq*()"), platform_get_irq_byname() displays an error
> when the IRQ isn't found. Since the SMMUv3 driver uses that function to
> query which interrupt method is available, the message is now displayed
> during boot for any SMMUv3 that doesn't implement the combined
> interrupt, or that implements MSIs.
> 
> [   20.700337] arm-smmu-v3 arm-smmu-v3.7.auto: IRQ combined not found
> [   20.706508] arm-smmu-v3 arm-smmu-v3.7.auto: IRQ eventq not found
> [   20.712503] arm-smmu-v3 arm-smmu-v3.7.auto: IRQ priq not found
> [   20.718325] arm-smmu-v3 arm-smmu-v3.7.auto: IRQ gerror not found
> 
> Use platform_get_irq_byname_optional() to avoid displaying a spurious
> error.
> 
> Fixes: 7723f4c5ecdb ("driver core: platform: Add an error message to platform_get_irq*()")
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

That stops a nuisance:
Tested-by: John Garry <john.garry@huawei.com>

However, I will say though that the combined irq seems necessary for 
TX2, which is not warned about being missing now.

Finally, A cover letter would have been handy to mention that the new 
API was only introduced after rc1

thanks

> ---
>   drivers/iommu/arm-smmu-v3.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index bfa4a0f39ed0..a89797f346a4 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -5207,19 +5207,19 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   
>   	/* Interrupt lines */
>   
> -	irq = platform_get_irq_byname(pdev, "combined");
> +	irq = platform_get_irq_byname_optional(pdev, "combined");
>   	if (irq > 0)
>   		smmu->combined_irq = irq;
>   	else {
> -		irq = platform_get_irq_byname(pdev, "eventq");
> +		irq = platform_get_irq_byname_optional(pdev, "eventq");
>   		if (irq > 0)
>   			smmu->evtq.q.irq = irq;
>   
> -		irq = platform_get_irq_byname(pdev, "priq");
> +		irq = platform_get_irq_byname_optional(pdev, "priq");
>   		if (irq > 0)
>   			smmu->priq.q.irq = irq;
>   
> -		irq = platform_get_irq_byname(pdev, "gerror");
> +		irq = platform_get_irq_byname_optional(pdev, "gerror");
>   		if (irq > 0)
>   			smmu->gerr_irq = irq;
>   	}
> 

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