drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 // Copyright (C) 2019-2020 NVIDIA CORPORATION.  All rights reserved.

 #include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

 #include <soc/tegra/mc.h>

 #include "arm-smmu.h"

 /*
  * Tegra194 has three ARM MMU-500 Instances.
  * Two of them are used together and must be programmed identically for
  * interleaved IOVA accesses across them and translates accesses from
  * non-isochronous HW devices.
  * Third one is used for translating accesses from isochronous HW devices.
  *
  * In addition, the SMMU driver needs to coordinate with the memory controller
  * driver to ensure that the right SID override is programmed for any given
  * memory client. This is necessary to allow for use-case such as seamlessly
  * handing over the display controller configuration from the firmware to the
  * kernel.
  *
  * This implementation supports programming of the two instances that must
  * be programmed identically and takes care of invoking the memory controller
  * driver for SID override programming after devices have been attached to an
  * SMMU instance.
  */
 #define MAX_SMMU_INSTANCES 2

 struct nvidia_smmu {
 	struct arm_smmu_device smmu;
 	void __iomem *bases[MAX_SMMU_INSTANCES];
 	unsigned int num_instances;
 	struct tegra_mc *mc;
 };

 static inline struct nvidia_smmu *to_nvidia_smmu(struct arm_smmu_device *smmu)
 {
 	return container_of(smmu, struct nvidia_smmu, smmu);
 }

 static inline void __iomem *nvidia_smmu_page(struct arm_smmu_device *smmu,
 					     unsigned int inst, int page)
 {
 	struct nvidia_smmu *nvidia_smmu;

 	nvidia_smmu = container_of(smmu, struct nvidia_smmu, smmu);
 	return nvidia_smmu->bases[inst] + (page << smmu->pgshift);
 }

 static u32 nvidia_smmu_read_reg(struct arm_smmu_device *smmu,
 				int page, int offset)
 {
 	void __iomem *reg = nvidia_smmu_page(smmu, 0, page) + offset;

 	return readl_relaxed(reg);
 }

 static void nvidia_smmu_write_reg(struct arm_smmu_device *smmu,
 				  int page, int offset, u32 val)
 {
 	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
 	unsigned int i;

 	for (i = 0; i < nvidia->num_instances; i++) {
 		void __iomem *reg = nvidia_smmu_page(smmu, i, page) + offset;

 		writel_relaxed(val, reg);
 	}
 }

 static u64 nvidia_smmu_read_reg64(struct arm_smmu_device *smmu,
 				  int page, int offset)
 {
 	void __iomem *reg = nvidia_smmu_page(smmu, 0, page) + offset;

 	return readq_relaxed(reg);
 }

 static void nvidia_smmu_write_reg64(struct arm_smmu_device *smmu,
 				    int page, int offset, u64 val)
 {
 	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
 	unsigned int i;

 	for (i = 0; i < nvidia->num_instances; i++) {
 		void __iomem *reg = nvidia_smmu_page(smmu, i, page) + offset;

 		writeq_relaxed(val, reg);
 	}
 }

 static void nvidia_smmu_tlb_sync(struct arm_smmu_device *smmu, int page,
 				 int sync, int status)
 {
 	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
 	unsigned int delay;

 	arm_smmu_writel(smmu, page, sync, 0);

 	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
 		unsigned int spin_cnt;

 		for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
 			u32 val = 0;
 			unsigned int i;

 			for (i = 0; i < nvidia->num_instances; i++) {
 				void __iomem *reg;

 				reg = nvidia_smmu_page(smmu, i, page) + status;
 				val |= readl_relaxed(reg);
 			}

 			if (!(val & 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 nvidia_smmu_reset(struct arm_smmu_device *smmu)
 {
 	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
 	unsigned int i;

 	for (i = 0; i < nvidia->num_instances; i++) {
 		u32 val;
 		void __iomem *reg = nvidia_smmu_page(smmu, i, ARM_SMMU_GR0) +
 				    ARM_SMMU_GR0_sGFSR;

 		/* clear global FSR */
 		val = readl_relaxed(reg);
 		writel_relaxed(val, reg);
 	}

 	return 0;
 }

 static irqreturn_t nvidia_smmu_global_fault_inst(int irq,
 						 struct arm_smmu_device *smmu,
 						 int inst)
 {
 	u32 gfsr, gfsynr0, gfsynr1, gfsynr2;
 	void __iomem *gr0_base = nvidia_smmu_page(smmu, inst, 0);

 	gfsr = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSR);
 	if (!gfsr)
 		return IRQ_NONE;

 	gfsynr0 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR0);
 	gfsynr1 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR1);
 	gfsynr2 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR2);

 	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, gr0_base + ARM_SMMU_GR0_sGFSR);
 	return IRQ_HANDLED;
 }

 static irqreturn_t nvidia_smmu_global_fault(int irq, void *dev)
 {
 	unsigned int inst;
 	irqreturn_t ret = IRQ_NONE;
 	struct arm_smmu_device *smmu = dev;
 	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);

 	for (inst = 0; inst < nvidia->num_instances; inst++) {
 		irqreturn_t irq_ret;

 		irq_ret = nvidia_smmu_global_fault_inst(irq, smmu, inst);
 		if (irq_ret == IRQ_HANDLED)
 			ret = IRQ_HANDLED;
 	}

 	return ret;
 }

 static irqreturn_t nvidia_smmu_context_fault_bank(int irq,
 						  struct arm_smmu_device *smmu,
 						  int idx, int inst)
 {
 	u32 fsr, fsynr, cbfrsynra;
 	unsigned long iova;
 	void __iomem *gr1_base = nvidia_smmu_page(smmu, inst, 1);
 	void __iomem *cb_base = nvidia_smmu_page(smmu, inst, smmu->numpage + idx);

 	fsr = readl_relaxed(cb_base + ARM_SMMU_CB_FSR);
 	if (!(fsr & ARM_SMMU_CB_FSR_FAULT))
 		return IRQ_NONE;

 	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(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, cb_base + ARM_SMMU_CB_FSR);
 	return IRQ_HANDLED;
 }

 static irqreturn_t nvidia_smmu_context_fault(int irq, void *dev)
 {
 	int idx;
 	unsigned int inst;
 	irqreturn_t ret = IRQ_NONE;
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_domain *smmu_domain = dev;
 	struct nvidia_smmu *nvidia;

 	smmu = smmu_domain->smmu;
 	nvidia = to_nvidia_smmu(smmu);

 	for (inst = 0; inst < nvidia->num_instances; inst++) {
 		irqreturn_t irq_ret;

 		/*
 		 * Interrupt line is shared between all contexts.
 		 * Check for faults across all contexts.
 		 */
 		for (idx = 0; idx < smmu->num_context_banks; idx++) {
 			irq_ret = nvidia_smmu_context_fault_bank(irq, smmu,
 								 idx, inst);
 			if (irq_ret == IRQ_HANDLED)
 				ret = IRQ_HANDLED;
 		}
 	}

 	return ret;
 }

 static void nvidia_smmu_probe_finalize(struct arm_smmu_device *smmu, struct device *dev)
 {
 	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
 	int err;

 	err = tegra_mc_probe_device(nvidia->mc, dev);
 	if (err < 0)
 		dev_err(smmu->dev, "memory controller probe failed for %s: %d\n",
 			dev_name(dev), err);
 }

 static int nvidia_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 				    struct io_pgtable_cfg *pgtbl_cfg,
 				    struct device *dev)
 {
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	const struct device_node *np = smmu->dev->of_node;

 	/*
 	 * Tegra194 and Tegra234 SoCs have the erratum that causes walk cache
 	 * entries to not be invalidated correctly. The problem is that the walk
 	 * cache index generated for IOVA is not same across translation and
 	 * invalidation requests. This is leading to page faults when PMD entry
 	 * is released during unmap and populated with new PTE table during
 	 * subsequent map request. Disabling large page mappings avoids the
 	 * release of PMD entry and avoid translations seeing stale PMD entry in
 	 * walk cache.
 	 * Fix this by limiting the page mappings to PAGE_SIZE on Tegra194 and
 	 * Tegra234.
 	 */
 	if (of_device_is_compatible(np, "nvidia,tegra234-smmu") ||
 	    of_device_is_compatible(np, "nvidia,tegra194-smmu")) {
 		smmu->pgsize_bitmap &= GENMASK(PAGE_SHIFT, 0);
 		pgtbl_cfg->pgsize_bitmap = smmu->pgsize_bitmap;
 	}

 	return 0;
 }

 static const struct arm_smmu_impl nvidia_smmu_impl = {
 	.read_reg = nvidia_smmu_read_reg,
 	.write_reg = nvidia_smmu_write_reg,
 	.read_reg64 = nvidia_smmu_read_reg64,
 	.write_reg64 = nvidia_smmu_write_reg64,
 	.reset = nvidia_smmu_reset,
 	.tlb_sync = nvidia_smmu_tlb_sync,
 	.global_fault = nvidia_smmu_global_fault,
 	.context_fault = nvidia_smmu_context_fault,
 	.probe_finalize = nvidia_smmu_probe_finalize,
 	.init_context = nvidia_smmu_init_context,
 };

 static const struct arm_smmu_impl nvidia_smmu_single_impl = {
 	.probe_finalize = nvidia_smmu_probe_finalize,
 	.init_context = nvidia_smmu_init_context,
 };

 struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
 {
 	struct resource *res;
 	struct device *dev = smmu->dev;
 	struct nvidia_smmu *nvidia_smmu;
 	struct platform_device *pdev = to_platform_device(dev);
 	unsigned int i;

 	nvidia_smmu = devm_krealloc(dev, smmu, sizeof(*nvidia_smmu), GFP_KERNEL);
 	if (!nvidia_smmu)
 		return ERR_PTR(-ENOMEM);

 	nvidia_smmu->mc = devm_tegra_memory_controller_get(dev);
 	if (IS_ERR(nvidia_smmu->mc))
 		return ERR_CAST(nvidia_smmu->mc);

 	/* Instance 0 is ioremapped by arm-smmu.c. */
 	nvidia_smmu->bases[0] = smmu->base;
 	nvidia_smmu->num_instances++;

 	for (i = 1; i < MAX_SMMU_INSTANCES; i++) {
 		res = platform_get_resource(pdev, IORESOURCE_MEM, i);
 		if (!res)
 			break;

 		nvidia_smmu->bases[i] = devm_ioremap_resource(dev, res);
 		if (IS_ERR(nvidia_smmu->bases[i]))
 			return ERR_CAST(nvidia_smmu->bases[i]);

 		nvidia_smmu->num_instances++;
 	}

 	if (nvidia_smmu->num_instances == 1)
 		nvidia_smmu->smmu.impl = &nvidia_smmu_single_impl;
 	else
 		nvidia_smmu->smmu.impl = &nvidia_smmu_impl;

 	return &nvidia_smmu->smmu;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	// Copyright (C) 2019-2020 NVIDIA CORPORATION. All rights reserved.

	#include <linux/bitfield.h>
	#include <linux/delay.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>

	#include <soc/tegra/mc.h>

	#include "arm-smmu.h"

	/*
	* Tegra194 has three ARM MMU-500 Instances.
	* Two of them are used together and must be programmed identically for
	* interleaved IOVA accesses across them and translates accesses from
	* non-isochronous HW devices.
	* Third one is used for translating accesses from isochronous HW devices.
	*
	* In addition, the SMMU driver needs to coordinate with the memory controller
	* driver to ensure that the right SID override is programmed for any given
	* memory client. This is necessary to allow for use-case such as seamlessly
	* handing over the display controller configuration from the firmware to the
	* kernel.
	*
	* This implementation supports programming of the two instances that must
	* be programmed identically and takes care of invoking the memory controller
	* driver for SID override programming after devices have been attached to an
	* SMMU instance.
	*/
	#define MAX_SMMU_INSTANCES 2

	struct nvidia_smmu {
	struct arm_smmu_device smmu;
	void __iomem *bases[MAX_SMMU_INSTANCES];
	unsigned int num_instances;
	struct tegra_mc *mc;
	};

	static inline struct nvidia_smmu to_nvidia_smmu(struct arm_smmu_device smmu)
	{
	return container_of(smmu, struct nvidia_smmu, smmu);
	}

	static inline void __iomem nvidia_smmu_page(struct arm_smmu_device smmu,
	unsigned int inst, int page)
	{
	struct nvidia_smmu *nvidia_smmu;

	nvidia_smmu = container_of(smmu, struct nvidia_smmu, smmu);
	return nvidia_smmu->bases[inst] + (page << smmu->pgshift);
	}

	static u32 nvidia_smmu_read_reg(struct arm_smmu_device *smmu,
	int page, int offset)
	{
	void __iomem *reg = nvidia_smmu_page(smmu, 0, page) + offset;

	return readl_relaxed(reg);
	}

	static void nvidia_smmu_write_reg(struct arm_smmu_device *smmu,
	int page, int offset, u32 val)
	{
	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
	unsigned int i;

	for (i = 0; i < nvidia->num_instances; i++) {
	void __iomem *reg = nvidia_smmu_page(smmu, i, page) + offset;

	writel_relaxed(val, reg);
	}
	}

	static u64 nvidia_smmu_read_reg64(struct arm_smmu_device *smmu,
	int page, int offset)
	{
	void __iomem *reg = nvidia_smmu_page(smmu, 0, page) + offset;

	return readq_relaxed(reg);
	}

	static void nvidia_smmu_write_reg64(struct arm_smmu_device *smmu,
	int page, int offset, u64 val)
	{
	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
	unsigned int i;

	for (i = 0; i < nvidia->num_instances; i++) {
	void __iomem *reg = nvidia_smmu_page(smmu, i, page) + offset;

	writeq_relaxed(val, reg);
	}
	}

	static void nvidia_smmu_tlb_sync(struct arm_smmu_device *smmu, int page,
	int sync, int status)
	{
	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
	unsigned int delay;

	arm_smmu_writel(smmu, page, sync, 0);

	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
	unsigned int spin_cnt;

	for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
	u32 val = 0;
	unsigned int i;

	for (i = 0; i < nvidia->num_instances; i++) {
	void __iomem *reg;

	reg = nvidia_smmu_page(smmu, i, page) + status;
	val \|= readl_relaxed(reg);
	}

	if (!(val & 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 nvidia_smmu_reset(struct arm_smmu_device *smmu)
	{
	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
	unsigned int i;

	for (i = 0; i < nvidia->num_instances; i++) {
	u32 val;
	void __iomem *reg = nvidia_smmu_page(smmu, i, ARM_SMMU_GR0) +
	ARM_SMMU_GR0_sGFSR;

	/* clear global FSR */
	val = readl_relaxed(reg);
	writel_relaxed(val, reg);
	}

	return 0;
	}

	static irqreturn_t nvidia_smmu_global_fault_inst(int irq,
	struct arm_smmu_device *smmu,
	int inst)
	{
	u32 gfsr, gfsynr0, gfsynr1, gfsynr2;
	void __iomem *gr0_base = nvidia_smmu_page(smmu, inst, 0);

	gfsr = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSR);
	if (!gfsr)
	return IRQ_NONE;

	gfsynr0 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR0);
	gfsynr1 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR1);
	gfsynr2 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR2);

	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, gr0_base + ARM_SMMU_GR0_sGFSR);
	return IRQ_HANDLED;
	}

	static irqreturn_t nvidia_smmu_global_fault(int irq, void *dev)
	{
	unsigned int inst;
	irqreturn_t ret = IRQ_NONE;
	struct arm_smmu_device *smmu = dev;
	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);

	for (inst = 0; inst < nvidia->num_instances; inst++) {
	irqreturn_t irq_ret;

	irq_ret = nvidia_smmu_global_fault_inst(irq, smmu, inst);
	if (irq_ret == IRQ_HANDLED)
	ret = IRQ_HANDLED;
	}

	return ret;
	}

	static irqreturn_t nvidia_smmu_context_fault_bank(int irq,
	struct arm_smmu_device *smmu,
	int idx, int inst)
	{
	u32 fsr, fsynr, cbfrsynra;
	unsigned long iova;
	void __iomem *gr1_base = nvidia_smmu_page(smmu, inst, 1);
	void __iomem *cb_base = nvidia_smmu_page(smmu, inst, smmu->numpage + idx);

	fsr = readl_relaxed(cb_base + ARM_SMMU_CB_FSR);
	if (!(fsr & ARM_SMMU_CB_FSR_FAULT))
	return IRQ_NONE;

	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(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, cb_base + ARM_SMMU_CB_FSR);
	return IRQ_HANDLED;
	}

	static irqreturn_t nvidia_smmu_context_fault(int irq, void *dev)
	{
	int idx;
	unsigned int inst;
	irqreturn_t ret = IRQ_NONE;
	struct arm_smmu_device *smmu;
	struct arm_smmu_domain *smmu_domain = dev;
	struct nvidia_smmu *nvidia;

	smmu = smmu_domain->smmu;
	nvidia = to_nvidia_smmu(smmu);

	for (inst = 0; inst < nvidia->num_instances; inst++) {
	irqreturn_t irq_ret;

	/*
	* Interrupt line is shared between all contexts.
	* Check for faults across all contexts.
	*/
	for (idx = 0; idx < smmu->num_context_banks; idx++) {
	irq_ret = nvidia_smmu_context_fault_bank(irq, smmu,
	idx, inst);
	if (irq_ret == IRQ_HANDLED)
	ret = IRQ_HANDLED;
	}
	}

	return ret;
	}

	static void nvidia_smmu_probe_finalize(struct arm_smmu_device smmu, struct device dev)
	{
	struct nvidia_smmu *nvidia = to_nvidia_smmu(smmu);
	int err;

	err = tegra_mc_probe_device(nvidia->mc, dev);
	if (err < 0)
	dev_err(smmu->dev, "memory controller probe failed for %s: %d\n",
	dev_name(dev), err);
	}

	static int nvidia_smmu_init_context(struct arm_smmu_domain *smmu_domain,
	struct io_pgtable_cfg *pgtbl_cfg,
	struct device *dev)
	{
	struct arm_smmu_device *smmu = smmu_domain->smmu;
	const struct device_node *np = smmu->dev->of_node;

	/*
	* Tegra194 and Tegra234 SoCs have the erratum that causes walk cache
	* entries to not be invalidated correctly. The problem is that the walk
	* cache index generated for IOVA is not same across translation and
	* invalidation requests. This is leading to page faults when PMD entry
	* is released during unmap and populated with new PTE table during
	* subsequent map request. Disabling large page mappings avoids the
	* release of PMD entry and avoid translations seeing stale PMD entry in
	* walk cache.
	* Fix this by limiting the page mappings to PAGE_SIZE on Tegra194 and
	* Tegra234.
	*/
	if (of_device_is_compatible(np, "nvidia,tegra234-smmu") \|\|
	of_device_is_compatible(np, "nvidia,tegra194-smmu")) {
	smmu->pgsize_bitmap &= GENMASK(PAGE_SHIFT, 0);
	pgtbl_cfg->pgsize_bitmap = smmu->pgsize_bitmap;
	}

	return 0;
	}

	static const struct arm_smmu_impl nvidia_smmu_impl = {
	.read_reg = nvidia_smmu_read_reg,
	.write_reg = nvidia_smmu_write_reg,
	.read_reg64 = nvidia_smmu_read_reg64,
	.write_reg64 = nvidia_smmu_write_reg64,
	.reset = nvidia_smmu_reset,
	.tlb_sync = nvidia_smmu_tlb_sync,
	.global_fault = nvidia_smmu_global_fault,
	.context_fault = nvidia_smmu_context_fault,
	.probe_finalize = nvidia_smmu_probe_finalize,
	.init_context = nvidia_smmu_init_context,
	};

	static const struct arm_smmu_impl nvidia_smmu_single_impl = {
	.probe_finalize = nvidia_smmu_probe_finalize,
	.init_context = nvidia_smmu_init_context,
	};

	struct arm_smmu_device nvidia_smmu_impl_init(struct arm_smmu_device smmu)
	{
	struct resource *res;
	struct device *dev = smmu->dev;
	struct nvidia_smmu *nvidia_smmu;
	struct platform_device *pdev = to_platform_device(dev);
	unsigned int i;

	nvidia_smmu = devm_krealloc(dev, smmu, sizeof(*nvidia_smmu), GFP_KERNEL);
	if (!nvidia_smmu)
	return ERR_PTR(-ENOMEM);

	nvidia_smmu->mc = devm_tegra_memory_controller_get(dev);
	if (IS_ERR(nvidia_smmu->mc))
	return ERR_CAST(nvidia_smmu->mc);

	/* Instance 0 is ioremapped by arm-smmu.c. */
	nvidia_smmu->bases[0] = smmu->base;
	nvidia_smmu->num_instances++;

	for (i = 1; i < MAX_SMMU_INSTANCES; i++) {
	res = platform_get_resource(pdev, IORESOURCE_MEM, i);
	if (!res)
	break;

	nvidia_smmu->bases[i] = devm_ioremap_resource(dev, res);
	if (IS_ERR(nvidia_smmu->bases[i]))
	return ERR_CAST(nvidia_smmu->bases[i]);

	nvidia_smmu->num_instances++;
	}

	if (nvidia_smmu->num_instances == 1)
	nvidia_smmu->smmu.impl = &nvidia_smmu_single_impl;
	else
	nvidia_smmu->smmu.impl = &nvidia_smmu_impl;

	return &nvidia_smmu->smmu;
	}