[PATCH v6 0/4] Nvidia Arm SMMUv2 Implementation

[PATCH v6 0/4] Nvidia Arm SMMUv2 Implementation

[Krishna Reddy]

Changes in v6:
Restricted the patch set to driver specific patches.
Fixed the cast warning reported by kbuild test robot.
Rebased on git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next

v5 - https://lkml.org/lkml/2020/5/21/1114
v4 - https://lkml.org/lkml/2019/10/30/1054
v3 - https://lkml.org/lkml/2019/10/18/1601
v2 - https://lkml.org/lkml/2019/9/2/980
v1 - https://lkml.org/lkml/2019/8/29/1588

Krishna Reddy (4):
  iommu/arm-smmu: add NVIDIA implementation for dual ARM MMU-500 usage
  dt-bindings: arm-smmu: Add binding for Tegra194 SMMU
  iommu/arm-smmu: Add global/context fault implementation hooks
  iommu/arm-smmu-nvidia: fix the warning reported by kbuild test robot

 .../devicetree/bindings/iommu/arm,smmu.yaml   |   5 +
 MAINTAINERS                                   |   2 +
 drivers/iommu/Makefile                        |   2 +-
 drivers/iommu/arm-smmu-impl.c                 |   3 +
 drivers/iommu/arm-smmu-nvidia.c               | 261 ++++++++++++++++++
 drivers/iommu/arm-smmu.c                      |  11 +-
 drivers/iommu/arm-smmu.h                      |   4 +
 7 files changed, 285 insertions(+), 3 deletions(-)
 create mode 100644 drivers/iommu/arm-smmu-nvidia.c


base-commit: 431275afdc7155415254aef4bd3816a1b8a2ead0
-- 
2.26.2


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[PATCH v6 1/4] iommu/arm-smmu: add NVIDIA implementation for dual ARM MMU-500 usage

[Krishna Reddy]

NVIDIA's Tegra194 soc uses two ARM MMU-500s together to interleave
IOVA accesses across them.
Add NVIDIA implementation for dual ARM MMU-500s and add new compatible
string for Tegra194 soc.

Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
---
 MAINTAINERS                     |   2 +
 drivers/iommu/Makefile          |   2 +-
 drivers/iommu/arm-smmu-impl.c   |   3 +
 drivers/iommu/arm-smmu-nvidia.c | 161 ++++++++++++++++++++++++++++++++
 drivers/iommu/arm-smmu.h        |   1 +
 5 files changed, 168 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iommu/arm-smmu-nvidia.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 50659d76976b7..118da0893c964 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16572,9 +16572,11 @@ F:	drivers/i2c/busses/i2c-tegra.c
 
 TEGRA IOMMU DRIVERS
 M:	Thierry Reding <thierry.reding@gmail.com>
+R:	Krishna Reddy <vdumpa@nvidia.com>
 L:	linux-tegra@vger.kernel.org
 S:	Supported
 F:	drivers/iommu/tegra*
+F:	drivers/iommu/arm-smmu-nvidia.c
 
 TEGRA KBC DRIVER
 M:	Laxman Dewangan <ldewangan@nvidia.com>
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 57cf4ba5e27cb..35542df00da72 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -15,7 +15,7 @@ obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o amd_iommu_quirks.o
 obj-$(CONFIG_AMD_IOMMU_DEBUGFS) += amd_iommu_debugfs.o
 obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
 obj-$(CONFIG_ARM_SMMU) += arm_smmu.o
-arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-qcom.o
+arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-qcom.o arm-smmu-nvidia.o
 obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
 obj-$(CONFIG_DMAR_TABLE) += dmar.o
 obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o intel-pasid.o
diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
index c75b9d957b702..52c84c30f83e4 100644
--- a/drivers/iommu/arm-smmu-impl.c
+++ b/drivers/iommu/arm-smmu-impl.c
@@ -160,6 +160,9 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
 	 */
 	switch (smmu->model) {
 	case ARM_MMU500:
+		if (of_device_is_compatible(smmu->dev->of_node,
+					    "nvidia,tegra194-smmu-500"))
+			return nvidia_smmu_impl_init(smmu);
 		smmu->impl = &arm_mmu500_impl;
 		break;
 	case CAVIUM_SMMUV2:
diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
new file mode 100644
index 0000000000000..dafc293a45217
--- /dev/null
+++ b/drivers/iommu/arm-smmu-nvidia.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Nvidia ARM SMMU v2 implementation quirks
+// Copyright (C) 2019 NVIDIA CORPORATION.  All rights reserved.
+
+#define pr_fmt(fmt) "nvidia-smmu: " fmt
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "arm-smmu.h"
+
+/* Tegra194 has three ARM MMU-500 Instances.
+ * Two of them are used together for Interleaved IOVA accesses and
+ * used by Non-Isochronous Hw devices for SMMU translations.
+ * Third one is used for SMMU translations from Isochronous HW devices.
+ * It is possible to use this Implementation to program either
+ * all three or two of the instances identically as desired through
+ * DT node.
+ *
+ * Programming all the three instances identically comes with redundant tlb
+ * invalidations as all three never need to be tlb invalidated for a HW device.
+ *
+ * When Linux Kernel supports multiple SMMU devices, The SMMU device used for
+ * Isochornous HW devices should be added as a separate ARM MMU-500 device
+ * in DT and be programmed independently for efficient tlb invalidates.
+ *
+ */
+#define MAX_SMMU_INSTANCES 3
+
+#define TLB_LOOP_TIMEOUT		1000000	/* 1s! */
+#define TLB_SPIN_COUNT			10
+
+struct nvidia_smmu {
+	struct arm_smmu_device	smmu;
+	unsigned int		num_inst;
+	void __iomem		*bases[MAX_SMMU_INSTANCES];
+};
+
+#define to_nvidia_smmu(s) container_of(s, struct nvidia_smmu, smmu)
+
+#define nsmmu_page(smmu, inst, page) \
+	(((inst) ? to_nvidia_smmu(smmu)->bases[(inst)] : smmu->base) + \
+	((page) << smmu->pgshift))
+
+static u32 nsmmu_read_reg(struct arm_smmu_device *smmu,
+			      int page, int offset)
+{
+	return readl_relaxed(nsmmu_page(smmu, 0, page) + offset);
+}
+
+static void nsmmu_write_reg(struct arm_smmu_device *smmu,
+			    int page, int offset, u32 val)
+{
+	unsigned int i;
+
+	for (i = 0; i < to_nvidia_smmu(smmu)->num_inst; i++)
+		writel_relaxed(val, nsmmu_page(smmu, i, page) + offset);
+}
+
+static u64 nsmmu_read_reg64(struct arm_smmu_device *smmu,
+				int page, int offset)
+{
+	return readq_relaxed(nsmmu_page(smmu, 0, page) + offset);
+}
+
+static void nsmmu_write_reg64(struct arm_smmu_device *smmu,
+				  int page, int offset, u64 val)
+{
+	unsigned int i;
+
+	for (i = 0; i < to_nvidia_smmu(smmu)->num_inst; i++)
+		writeq_relaxed(val, nsmmu_page(smmu, i, page) + offset);
+}
+
+static void nsmmu_tlb_sync(struct arm_smmu_device *smmu, int page,
+			   int sync, int status)
+{
+	u32 reg;
+	unsigned int i;
+	unsigned int spin_cnt, delay;
+
+	arm_smmu_writel(smmu, page, sync, 0);
+
+	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
+		for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
+			reg = 0;
+			for (i = 0; i < to_nvidia_smmu(smmu)->num_inst; i++) {
+				reg |= readl_relaxed(
+					nsmmu_page(smmu, i, page) + status);
+			}
+			if (!(reg & ARM_SMMU_sTLBGSTATUS_GSACTIVE))
+				return;
+			cpu_relax();
+		}
+		udelay(delay);
+	}
+	dev_err_ratelimited(smmu->dev,
+			    "TLB sync timed out -- SMMU may be deadlocked\n");
+}
+
+static int nsmmu_reset(struct arm_smmu_device *smmu)
+{
+	u32 reg;
+	unsigned int i;
+
+	for (i = 0; i < to_nvidia_smmu(smmu)->num_inst; i++) {
+		/* clear global FSR */
+		reg = readl_relaxed(nsmmu_page(smmu, i, ARM_SMMU_GR0) +
+				    ARM_SMMU_GR0_sGFSR);
+		writel_relaxed(reg, nsmmu_page(smmu, i, ARM_SMMU_GR0) +
+				    ARM_SMMU_GR0_sGFSR);
+	}
+
+	return 0;
+}
+
+static const struct arm_smmu_impl nvidia_smmu_impl = {
+	.read_reg = nsmmu_read_reg,
+	.write_reg = nsmmu_write_reg,
+	.read_reg64 = nsmmu_read_reg64,
+	.write_reg64 = nsmmu_write_reg64,
+	.reset = nsmmu_reset,
+	.tlb_sync = nsmmu_tlb_sync,
+};
+
+struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
+{
+	unsigned int i;
+	struct nvidia_smmu *nsmmu;
+	struct resource *res;
+	struct device *dev = smmu->dev;
+	struct platform_device *pdev = to_platform_device(smmu->dev);
+
+	nsmmu = devm_kzalloc(smmu->dev, sizeof(*nsmmu), GFP_KERNEL);
+	if (!nsmmu)
+		return ERR_PTR(-ENOMEM);
+
+	nsmmu->smmu = *smmu;
+	/* Instance 0 is ioremapped by arm-smmu.c */
+	nsmmu->num_inst = 1;
+
+	for (i = 1; i < MAX_SMMU_INSTANCES; i++) {
+		res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+		if (!res)
+			break;
+		nsmmu->bases[i] = devm_ioremap_resource(dev, res);
+		if (IS_ERR(nsmmu->bases[i]))
+			return (struct arm_smmu_device *)nsmmu->bases[i];
+		nsmmu->num_inst++;
+	}
+
+	nsmmu->smmu.impl = &nvidia_smmu_impl;
+	devm_kfree(smmu->dev, smmu);
+	pr_info("NVIDIA ARM SMMU Implementation, Instances=%d\n",
+		nsmmu->num_inst);
+
+	return &nsmmu->smmu;
+}
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index d172c024be618..d88374b68da31 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -451,6 +451,7 @@ static inline void arm_smmu_writeq(struct arm_smmu_device *smmu, int page,
 
 struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu);
 struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu);
+struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu);
 
 int arm_mmu500_reset(struct arm_smmu_device *smmu);
 
-- 
2.26.2


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RE: [PATCH v6 1/4] iommu/arm-smmu: add NVIDIA implementation for dual ARM MMU-500 usage

[Krishna Reddy]

>Should NVIDIA_TEGRA194_SMMU be a separate value for smmu->model, perhaps? That way we avoid this somewhat odd check here.

NVIDIA haven't made any changes to arm,mmu-500. It is only used in different topology.  New model would be mis-leading here.
As suggested by Robin, It can just be moved to end of function.

>> diff --git a/drivers/iommu/arm-smmu-nvidia.c 
>> b/drivers/iommu/arm-smmu-nvidia.c
>I wonder if it would be better to name this arm-smmu-tegra.c to make it clearer that this is for a Tegra chip. We do have regular expressions in MAINTAINERS that catch anything with "tegra" in it to make this easier.
>Also, the nsmmu_ prefix looks somewhat odd here. You already use struct nvidia_smmu as the name of the structure, so why not be consistent and continue to use nvidia_smmu_ as the prefix for function names?
>Or perhaps even use tegra_smmu_ as the prefix to match the filename change I suggested earlier.

Prefix can be updated to nvidia_smmu as we seem to be okay for now to keep file name as arm-smmu-nvidia.c after the vendor name.  

>> +#define TLB_LOOP_TIMEOUT		1000000	/* 1s! */
>USEC_PER_SEC?

It is not meant for a conversion. Reused Timeout variable from arm-smmu.c for tlb_sync implementation.  Can rename it to TLB_LOOP_TIMEOUT_IN_US.


>> +	}
>> +	dev_err_ratelimited(smmu->dev,
>> +			    "TLB sync timed out -- SMMU may be deadlocked\n");
>Same here.
>Also, is there anything we can do when this happens?

This is never expected to happen on Silicon. This code and message is reused from arm-smmu.c.


>> +#define nsmmu_page(smmu, inst, page) \
>> +	(((inst) ? to_nvidia_smmu(smmu)->bases[(inst)] : smmu->base) + \
>> +	((page) << smmu->pgshift))

>Can we simply define to_nvidia_smmu(smmu)->bases[0] = smmu->base in nvidia_smmu_impl_init()? Then this would become just:
>	to_nvidia_smmu(smmu)->bases[inst] + ((page) << (smmu)->pgshift)
> +
>Maybe add this here to simplify the nsmmu_page() macro above:
>	nsmmu->bases[0] = smmu->base;

This preferred to avoid the check in nsmmu_page(). But, smmu->base is not yet populated when nvidia_smmu_impl_init() is called.  
Let me look at the alternative place to set it.

-KR

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[PATCH v6 2/4] dt-bindings: arm-smmu: Add binding for Tegra194 SMMU

[Krishna Reddy]

Add binding for NVIDIA's Tegra194 Soc SMMU that is based
on ARM MMU-500.

Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
---
 Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
index e3ef1c69d1326..8f7ffd248f303 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
@@ -37,6 +37,11 @@ properties:
               - qcom,sc7180-smmu-500
               - qcom,sdm845-smmu-500
           - const: arm,mmu-500
+      - description: NVIDIA SoCs that use more than one "arm,mmu-500"
+        items:
+          - enum:
+              - nvdia,tegra194-smmu-500
+          - const: arm,mmu-500
       - items:
           - const: arm,mmu-500
           - const: arm,smmu-v2
-- 
2.26.2


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RE: [PATCH v6 2/4] dt-bindings: arm-smmu: Add binding for Tegra194 SMMU

[Krishna Reddy]

>> +              - nvdia,tegra194-smmu-500
>The -500 suffix here seems a bit redundant since there's no other type of SMMU in Tegra194, correct?

Yeah, there is only one type of SMMU supported in T194. It was added to be synonymous with mmu-500.  Can be removed.

-KR

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[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@nvidia.com>
---
 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


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[PATCH v6 4/4] iommu/arm-smmu-nvidia: fix the warning reported by kbuild test robot

[Krishna Reddy]

>> drivers/iommu/arm-smmu-nvidia.c:151:33: sparse: sparse: cast removes
>> address space '<asn:2>' of expression

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
---
 drivers/iommu/arm-smmu-nvidia.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
index 5999b6a770992..6348d8dc17fc2 100644
--- a/drivers/iommu/arm-smmu-nvidia.c
+++ b/drivers/iommu/arm-smmu-nvidia.c
@@ -248,7 +248,7 @@ struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
 			break;
 		nsmmu->bases[i] = devm_ioremap_resource(dev, res);
 		if (IS_ERR(nsmmu->bases[i]))
-			return (struct arm_smmu_device *)nsmmu->bases[i];
+			return ERR_CAST(nsmmu->bases[i]);
 		nsmmu->num_inst++;
 	}
 
-- 
2.26.2


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