iommu/arm-smmu: Implement .trigger_fault

In order to facilitate debugging and development, implement the
.trigger_fault method from iommu_ops.  This can be done on ARM SMMUv2 by
writing to the FSRRESTORE register.  Do it.

Change-Id: Ia8339b54fbb9263d8cf23ff61c4615122316729a
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 1124ff3..d669888 100644 (file)
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -199,6 +199,7 @@
 #define ARM_SMMU_CB_PAR_LO             0x50
 #define ARM_SMMU_CB_PAR_HI             0x54
 #define ARM_SMMU_CB_FSR                        0x58
+#define ARM_SMMU_CB_FSRRESTORE         0x5c
 #define ARM_SMMU_CB_FAR_LO             0x60
 #define ARM_SMMU_CB_FAR_HI             0x64
 #define ARM_SMMU_CB_FSYNR0             0x68
@@ -1166,6 +1167,29 @@ static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
        return IRQ_HANDLED;
 }
 
+static void arm_smmu_trigger_fault(struct iommu_domain *domain)
+{
+       struct arm_smmu_domain *smmu_domain = domain->priv;
+       struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+       struct arm_smmu_device *smmu;
+       void __iomem *cb_base;
+
+       if (!smmu_domain->smmu) {
+               pr_err("Can't trigger faults on non-attached domains\n");
+               return;
+       }
+
+       smmu = smmu_domain->smmu;
+
+       cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
+       arm_smmu_enable_clocks(smmu);
+       /* trigger a translation fault */
+       dev_err(smmu->dev, "Triggering translation fault on cb %d\n",
+               cfg->cbndx);
+       writel_relaxed(FSR_TF, cb_base + ARM_SMMU_CB_FSRRESTORE);
+       arm_smmu_disable_clocks(smmu);
+}
+
 static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
                                       struct io_pgtable_cfg *pgtbl_cfg)
 {
@@ -2252,6 +2276,7 @@ static struct iommu_ops arm_smmu_ops = {
        .domain_set_attr        = arm_smmu_domain_set_attr,
        .pgsize_bitmap          = -1UL, /* Restricted during device attach */
        .dma_supported          = arm_smmu_dma_supported,
+       .trigger_fault          = arm_smmu_trigger_fault,
 };
 
 static void arm_smmu_device_reset(struct arm_smmu_device *smmu)