[PATCH v6 3/4] iommu/arm-smmu: Add global/context fault implementation hooks

[Krishna Reddy]

Add global/context fault hooks to allow NVIDIA SMMU implementation
handle faults across multiple SMMUs.

Signed-off-by: Krishna Reddy <vdumpa@xxxxxxxxxx>
---
 drivers/iommu/arm-smmu-nvidia.c | 100 ++++++++++++++++++++++++++++++++
 drivers/iommu/arm-smmu.c        |  11 +++-
 drivers/iommu/arm-smmu.h        |   3 +
 3 files changed, 112 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
index dafc293a45217..5999b6a770992 100644
--- a/drivers/iommu/arm-smmu-nvidia.c
+++ b/drivers/iommu/arm-smmu-nvidia.c
@@ -117,6 +117,104 @@ static int nsmmu_reset(struct arm_smmu_device *smmu)
 	return 0;
 }
 
+static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct arm_smmu_domain, domain);
+}
+
+static irqreturn_t nsmmu_global_fault_inst(int irq,
+					       struct arm_smmu_device *smmu,
+					       int inst)
+{
+	u32 gfsr, gfsynr0, gfsynr1, gfsynr2;
+
+	gfsr = readl_relaxed(nsmmu_page(smmu, inst, 0) + ARM_SMMU_GR0_sGFSR);
+	gfsynr0 = readl_relaxed(nsmmu_page(smmu, inst, 0) +
+				ARM_SMMU_GR0_sGFSYNR0);
+	gfsynr1 = readl_relaxed(nsmmu_page(smmu, inst, 0) +
+				ARM_SMMU_GR0_sGFSYNR1);
+	gfsynr2 = readl_relaxed(nsmmu_page(smmu, inst, 0) +
+				ARM_SMMU_GR0_sGFSYNR2);
+
+	if (!gfsr)
+		return IRQ_NONE;
+
+	dev_err_ratelimited(smmu->dev,
+		"Unexpected global fault, this could be serious\n");
+	dev_err_ratelimited(smmu->dev,
+		"\tGFSR 0x%08x, GFSYNR0 0x%08x, GFSYNR1 0x%08x, GFSYNR2 0x%08x\n",
+		gfsr, gfsynr0, gfsynr1, gfsynr2);
+
+	writel_relaxed(gfsr, nsmmu_page(smmu, inst, 0) + ARM_SMMU_GR0_sGFSR);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t nsmmu_global_fault(int irq, void *dev)
+{
+	int inst;
+	irqreturn_t irq_ret = IRQ_NONE;
+	struct arm_smmu_device *smmu = dev;
+
+	for (inst = 0; inst < to_nvidia_smmu(smmu)->num_inst; inst++) {
+		irq_ret = nsmmu_global_fault_inst(irq, smmu, inst);
+		if (irq_ret == IRQ_HANDLED)
+			return irq_ret;
+	}
+
+	return irq_ret;
+}
+
+static irqreturn_t nsmmu_context_fault_bank(int irq,
+					    struct arm_smmu_device *smmu,
+					    int idx, int inst)
+{
+	u32 fsr, fsynr, cbfrsynra;
+	unsigned long iova;
+
+	fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
+	if (!(fsr & ARM_SMMU_FSR_FAULT))
+		return IRQ_NONE;
+
+	fsynr = readl_relaxed(nsmmu_page(smmu, inst, smmu->numpage + idx) +
+			      ARM_SMMU_CB_FSYNR0);
+	iova = readq_relaxed(nsmmu_page(smmu, inst, smmu->numpage + idx) +
+			     ARM_SMMU_CB_FAR);
+	cbfrsynra = readl_relaxed(nsmmu_page(smmu, inst, 1) +
+				  ARM_SMMU_GR1_CBFRSYNRA(idx));
+
+	dev_err_ratelimited(smmu->dev,
+	"Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
+			    fsr, iova, fsynr, cbfrsynra, idx);
+
+	writel_relaxed(fsr, nsmmu_page(smmu, inst, smmu->numpage + idx) +
+			    ARM_SMMU_CB_FSR);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t nsmmu_context_fault(int irq, void *dev)
+{
+	int inst, idx;
+	irqreturn_t irq_ret = IRQ_NONE;
+	struct iommu_domain *domain = dev;
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+	for (inst = 0; inst < to_nvidia_smmu(smmu)->num_inst; inst++) {
+		/* Interrupt line shared between all context faults.
+		 * Check for faults across all contexts.
+		 */
+		for (idx = 0; idx < smmu->num_context_banks; idx++) {
+			irq_ret = nsmmu_context_fault_bank(irq, smmu,
+							   idx, inst);
+
+			if (irq_ret == IRQ_HANDLED)
+				return irq_ret;
+		}
+	}
+
+	return irq_ret;
+}
+
 static const struct arm_smmu_impl nvidia_smmu_impl = {
 	.read_reg = nsmmu_read_reg,
 	.write_reg = nsmmu_write_reg,
@@ -124,6 +222,8 @@ static const struct arm_smmu_impl nvidia_smmu_impl = {
 	.write_reg64 = nsmmu_write_reg64,
 	.reset = nsmmu_reset,
 	.tlb_sync = nsmmu_tlb_sync,
+	.global_fault = nsmmu_global_fault,
+	.context_fault = nsmmu_context_fault,
 };
 
 struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 243bc4cb2705b..d720e1e191176 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -673,6 +673,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 	enum io_pgtable_fmt fmt;
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+	irqreturn_t (*context_fault)(int irq, void *dev);
 
 	mutex_lock(&smmu_domain->init_mutex);
 	if (smmu_domain->smmu)
@@ -835,7 +836,9 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 	 * handler seeing a half-initialised domain state.
 	 */
 	irq = smmu->irqs[smmu->num_global_irqs + cfg->irptndx];
-	ret = devm_request_irq(smmu->dev, irq, arm_smmu_context_fault,
+	context_fault = (smmu->impl && smmu->impl->context_fault) ?
+			 smmu->impl->context_fault : arm_smmu_context_fault;
+	ret = devm_request_irq(smmu->dev, irq, context_fault,
 			       IRQF_SHARED, "arm-smmu-context-fault", domain);
 	if (ret < 0) {
 		dev_err(smmu->dev, "failed to request context IRQ %d (%u)\n",
@@ -2107,6 +2110,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 	struct arm_smmu_device *smmu;
 	struct device *dev = &pdev->dev;
 	int num_irqs, i, err;
+	irqreturn_t (*global_fault)(int irq, void *dev);
 
 	smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
 	if (!smmu) {
@@ -2193,9 +2197,12 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		smmu->num_context_irqs = smmu->num_context_banks;
 	}
 
+	global_fault = (smmu->impl && smmu->impl->global_fault) ?
+			smmu->impl->global_fault : arm_smmu_global_fault;
+
 	for (i = 0; i < smmu->num_global_irqs; ++i) {
 		err = devm_request_irq(smmu->dev, smmu->irqs[i],
-				       arm_smmu_global_fault,
+				       global_fault,
 				       IRQF_SHARED,
 				       "arm-smmu global fault",
 				       smmu);
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index d88374b68da31..f8ce34c07d961 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -18,6 +18,7 @@
 #include <linux/io-64-nonatomic-hi-lo.h>
 #include <linux/io-pgtable.h>
 #include <linux/iommu.h>
+#include <linux/irqreturn.h>
 #include <linux/mutex.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
@@ -387,6 +388,8 @@ struct arm_smmu_impl {
 	void (*tlb_sync)(struct arm_smmu_device *smmu, int page, int sync,
 			 int status);
 	int (*def_domain_type)(struct device *dev);
+	irqreturn_t (*global_fault)(int irq, void *dev);
+	irqreturn_t (*context_fault)(int irq, void *dev);
 };
 
 static inline void __iomem *arm_smmu_page(struct arm_smmu_device *smmu, int n)
-- 
2.26.2