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iommu/arm-smmu-v3: Warn about missing IRQs

Message ID f03a7c9f0be2f0af461b61d18fff3c931da77ebb.1509109598.git.robin.murphy@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Robin Murphy Oct. 27, 2017, 1:08 p.m. UTC
It is annoyingly non-obvious when DMA transactions silently go missing
due to undetected SMMU faults. Help skip the first few debugging steps
in those situations by making it clear when we have neither wired IRQs
nor MSIs with which to raise error conditions.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/arm-smmu-v3.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Will Deacon Oct. 27, 2017, 4:52 p.m. UTC | #1
On Fri, Oct 27, 2017 at 02:08:16PM +0100, Robin Murphy wrote:
> It is annoyingly non-obvious when DMA transactions silently go missing
> due to undetected SMMU faults. Help skip the first few debugging steps
> in those situations by making it clear when we have neither wired IRQs
> nor MSIs with which to raise error conditions.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>  drivers/iommu/arm-smmu-v3.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index e67ba6c40faf..1a374c5c9507 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2263,6 +2263,8 @@ static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
>  						"arm-smmu-v3-evtq", smmu);
>  		if (ret < 0)
>  			dev_warn(smmu->dev, "failed to enable evtq irq\n");
> +	} else {
> +		dev_warn(smmu->dev, "no evtq irq - events will not be reported!\n");
>  	}
>  
>  	irq = smmu->cmdq.q.irq;
> @@ -2280,6 +2282,8 @@ static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
>  				       0, "arm-smmu-v3-gerror", smmu);
>  		if (ret < 0)
>  			dev_warn(smmu->dev, "failed to enable gerror irq\n");
> +	} else {
> +		dev_warn(smmu->dev, "no gerr irq - errors will not be reported!\n");
>  	}
>  
>  	if (smmu->features & ARM_SMMU_FEAT_PRI) {

Can we also print something similar for the PRIQ when we detect that PRI is
supported, please? Whilst I agree that event and gerror are the critical
ones, I'm not sure how a PCIe device behaves if its PRI requests are
ignored, but this might help to debug it.

Will
diff mbox

Patch

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index e67ba6c40faf..1a374c5c9507 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2263,6 +2263,8 @@  static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
 						"arm-smmu-v3-evtq", smmu);
 		if (ret < 0)
 			dev_warn(smmu->dev, "failed to enable evtq irq\n");
+	} else {
+		dev_warn(smmu->dev, "no evtq irq - events will not be reported!\n");
 	}
 
 	irq = smmu->cmdq.q.irq;
@@ -2280,6 +2282,8 @@  static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
 				       0, "arm-smmu-v3-gerror", smmu);
 		if (ret < 0)
 			dev_warn(smmu->dev, "failed to enable gerror irq\n");
+	} else {
+		dev_warn(smmu->dev, "no gerr irq - errors will not be reported!\n");
 	}
 
 	if (smmu->features & ARM_SMMU_FEAT_PRI) {