iommu/arm-smmu: Log CBFRSYNRA register on context fault

Bits[15:0] in CBFRSYNRA register contain information about
StreamID of the incoming transaction that generated the
fault. Dump CBFRSYNRA register to get this info.
This is specially useful in a distributed SMMU architecture
where multiple masters are connected to the SMMU.
SID information helps to quickly identify the faulting
master device.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 7 insertions, 3 deletions

diff --git a/drivers/iommu/arm-smmu-regs.h b/drivers/iommu/arm-smmu-regs.h
index a1226e4ab5f8..e9132a926761 100644
--- a/drivers/iommu/arm-smmu-regs.h
+++ b/drivers/iommu/arm-smmu-regs.h
@@ -147,6 +147,8 @@ enum arm_smmu_s2cr_privcfg {
 #define CBAR_IRPTNDX_SHIFT              24
 #define CBAR_IRPTNDX_MASK               0xff
 
+#define ARM_SMMU_GR1_CBFRSYNRA(n)       (0x400 + ((n) << 2))
+
 #define ARM_SMMU_GR1_CBA2R(n)           (0x800 + ((n) << 2))
 #define CBA2R_RW64_32BIT                (0 << 0)
 #define CBA2R_RW64_64BIT                (1 << 0)
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 930c07635956..5e54cc0a28b3 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -570,12 +570,13 @@ static const struct iommu_gather_ops arm_smmu_s2_tlb_ops_v1 = {
 
 static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 {
-        u32 fsr, fsynr;
+        u32 fsr, fsynr, cbfrsynra;
         unsigned long iova;
         struct iommu_domain *domain = dev;
         struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
         struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
         struct arm_smmu_device *smmu = smmu_domain->smmu;
+        void __iomem *gr1_base = ARM_SMMU_GR1(smmu);
         void __iomem *cb_base;
 
         cb_base = ARM_SMMU_CB(smmu, cfg->cbndx);
@@ -586,10 +587,11 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 
         fsynr = readl_relaxed(cb_base + ARM_SMMU_CB_FSYNR0);
         iova = readq_relaxed(cb_base + ARM_SMMU_CB_FAR);
+        cbfrsynra = readl_relaxed(gr1_base + ARM_SMMU_GR1_CBFRSYNRA(cfg->cbndx));
 
         dev_err_ratelimited(smmu->dev,
-        "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cb=%d\n",
-                            fsr, iova, fsynr, cfg->cbndx);
+        "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
+                            fsr, iova, fsynr, cbfrsynra, cfg->cbndx);
 
         writel(fsr, cb_base + ARM_SMMU_CB_FSR);
         return IRQ_HANDLED;