From: Robin Murphy <robin.murphy@arm.com>
To: will@kernel.org, joro@8bytes.org
Cc: iommu@lists.linux-foundation.org,
Douglas Anderson <dianders@chromium.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] iommu/arm-smmu: Report USF more clearly
Date: Fri, 13 Sep 2019 12:48:37 +0100 [thread overview]
Message-ID: <2762ffd4c196dc91d62e10eb8b753f256ea9b629.1568375317.git.robin.murphy@arm.com> (raw)
Although CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT is a welcome tool
for smoking out inadequate firmware, the failure mode is non-obvious
and can be confusing for end users. Add some special-case reporting of
Unidentified Stream Faults to help clarify this particular symptom.
CC: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/arm-smmu.c | 5 +++++
drivers/iommu/arm-smmu.h | 2 ++
2 files changed, 7 insertions(+)
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index b7cf24402a94..76ac8c180695 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -499,6 +499,11 @@ static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
dev_err_ratelimited(smmu->dev,
"\tGFSR 0x%08x, GFSYNR0 0x%08x, GFSYNR1 0x%08x, GFSYNR2 0x%08x\n",
gfsr, gfsynr0, gfsynr1, gfsynr2);
+ if (IS_ENABLED(CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT) &&
+ (gfsr & sGFSR_USF))
+ dev_err_ratelimited(smmu->dev,
+ "Stream ID %hu may not be described by firmware, try booting with \"arm-smmu.disable_bypass=0\"\n",
+ (u16)gfsynr1);
arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_sGFSR, gfsr);
return IRQ_HANDLED;
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index c9c13b5785f2..46f7e161e83e 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -79,6 +79,8 @@
#define ID7_MINOR GENMASK(3, 0)
#define ARM_SMMU_GR0_sGFSR 0x48
+#define sGFSR_USF BIT(2)
+
#define ARM_SMMU_GR0_sGFSYNR0 0x50
#define ARM_SMMU_GR0_sGFSYNR1 0x54
#define ARM_SMMU_GR0_sGFSYNR2 0x58
--
2.21.0.dirty
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next reply other threads:[~2019-09-13 11:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 11:48 Robin Murphy [this message]
2019-09-13 14:34 ` [PATCH] iommu/arm-smmu: Report USF more clearly Robin Murphy
2019-09-13 14:35 ` Qian Cai
2019-09-13 14:43 ` Robin Murphy
2019-09-13 22:44 ` Doug Anderson
2019-09-16 18:00 ` Will Deacon
2019-09-16 18:19 ` Doug Anderson
2019-09-16 21:42 ` Robin Murphy
2019-09-13 22:59 ` Russell King - ARM Linux admin
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