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From: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
To: will.deacon-5wv7dgnIgG8@public.gmane.org
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: [PATCH v2] iommu/arm-smmu-v3: Warn about missing IRQs
Date: Mon, 30 Oct 2017 12:14:02 +0000	[thread overview]
Message-ID: <3bb431bfe78553db82a0e267263ac58781a2dd25.1509364684.git.robin.murphy@arm.com> (raw)

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-5wv7dgnIgG8@public.gmane.org>
---

v2: Cover PRI for completeness, even if the "broken" vs. "does nothing"
    distinction doesn't matter much at the moment.

 drivers/iommu/arm-smmu-v3.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index e67ba6c40faf..343025a39478 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) {
@@ -2293,6 +2297,8 @@ static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
 			if (ret < 0)
 				dev_warn(smmu->dev,
 					 "failed to enable priq irq\n");
+		} else {
+			dev_warn(smmu->dev, "no priq irq - PRI will be broken\n");
 		}
 	}
 }
-- 
2.13.4.dirty

WARNING: multiple messages have this Message-ID (diff)
From: robin.murphy@arm.com (Robin Murphy)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] iommu/arm-smmu-v3: Warn about missing IRQs
Date: Mon, 30 Oct 2017 12:14:02 +0000	[thread overview]
Message-ID: <3bb431bfe78553db82a0e267263ac58781a2dd25.1509364684.git.robin.murphy@arm.com> (raw)

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>
---

v2: Cover PRI for completeness, even if the "broken" vs. "does nothing"
    distinction doesn't matter much at the moment.

 drivers/iommu/arm-smmu-v3.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index e67ba6c40faf..343025a39478 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) {
@@ -2293,6 +2297,8 @@ static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
 			if (ret < 0)
 				dev_warn(smmu->dev,
 					 "failed to enable priq irq\n");
+		} else {
+			dev_warn(smmu->dev, "no priq irq - PRI will be broken\n");
 		}
 	}
 }
-- 
2.13.4.dirty

             reply	other threads:[~2017-10-30 12:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-30 12:14 Robin Murphy [this message]
2017-10-30 12:14 ` [PATCH v2] iommu/arm-smmu-v3: Warn about missing IRQs Robin Murphy

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