diff --git a/xen/drivers/passthrough/arm/Makefile b/xen/drivers/passthrough/arm/Makefile
index f4cd26e..57a6da6 100644
--- a/xen/drivers/passthrough/arm/Makefile
+++ b/xen/drivers/passthrough/arm/Makefile
@@ -1,2 +1,3 @@
 obj-y += iommu.o
 obj-y += smmu.o
+obj-y += smmu-v3.o
diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index 380969a..8f3b43d 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -18,28 +18,266 @@
  * Author: Will Deacon <will.deacon@arm.com>
  *
  * This driver is powered by bad coffee and bombay mix.
+ *
+ *
+ * Based on Linux drivers/iommu/arm-smmu-v3.c
+ * => commit bdf95923086fb359ccb44c815724c3ace1611c90
+ *
+ * Xen modifications:
+ * Sameer Goel <sgoel@codeaurora.org>
+ * Copyright (C) 2017, The Linux Foundation, All rights reserved.
+ *
  */
 
-#include <linux/acpi.h>
-#include <linux/acpi_iort.h>
-#include <linux/delay.h>
-#include <linux/dma-iommu.h>
-#include <linux/err.h>
-#include <linux/interrupt.h>
-#include <linux/iommu.h>
-#include <linux/iopoll.h>
-#include <linux/module.h>
-#include <linux/msi.h>
-#include <linux/of.h>
-#include <linux/of_address.h>
-#include <linux/of_iommu.h>
-#include <linux/of_platform.h>
-#include <linux/pci.h>
-#include <linux/platform_device.h>
-
-#include <linux/amba/bus.h>
-
-#include "io-pgtable.h"
+#include <xen/config.h>
+#include <xen/delay.h>
+#include <xen/errno.h>
+#include <xen/err.h>
+#include <xen/irq.h>
+#include <xen/lib.h>
+#include <xen/list.h>
+#include <xen/mm.h>
+#include <xen/vmap.h>
+#include <xen/rbtree.h>
+#include <xen/sched.h>
+#include <xen/sizes.h>
+#include <asm/atomic.h>
+#include <asm/device.h>
+#include <asm/io.h>
+#include <asm/platform.h>
+#include <xen/acpi.h>
+
+typedef paddr_t phys_addr_t;
+typedef paddr_t dma_addr_t;
+
+/* Alias to Xen device tree helpers */
+#define device_node dt_device_node
+#define of_phandle_args dt_phandle_args
+#define of_device_id dt_device_match
+#define of_match_node dt_match_node
+#define of_property_read_u32(np, pname, out) (!dt_property_read_u32(np, pname, out))
+#define of_property_read_bool dt_property_read_bool
+#define of_parse_phandle_with_args dt_parse_phandle_with_args
+#define mutex spinlock_t
+#define mutex_init spin_lock_init
+#define mutex_lock spin_lock
+#define mutex_unlock spin_unlock
+
+/* Xen: Helpers to get device MMIO and IRQs */
+struct resource {
+	u64 addr;
+	u64 size;
+	unsigned int type;
+};
+
+#define resource_size(res) ((res)->size)
+
+#define platform_device device
+
+#define IORESOURCE_MEM 0
+#define IORESOURCE_IRQ 1
+
+static struct resource *platform_get_resource(struct platform_device *pdev,
+					      unsigned int type,
+					      unsigned int num)
+{
+	/*
+	 * The resource is only used between 2 calls of platform_get_resource.
+	 * It's quite ugly but it's avoid to add too much code in the part
+	 * imported from Linux
+	 */
+	static struct resource res;
+	struct acpi_iort_node *iort_node;
+	struct acpi_iort_smmu_v3 *node_smmu_data;
+	int ret = 0;
+
+	res.type = type;
+
+	switch (type) {
+	case IORESOURCE_MEM:
+		if (pdev->type == DEV_ACPI) {
+			ret = 1;
+			iort_node = pdev->acpi_node;
+			node_smmu_data =
+				(struct acpi_iort_smmu_v3 *)iort_node->node_data;
+
+			if (node_smmu_data != NULL) {
+				res.addr = node_smmu_data->base_address;
+				res.size = SZ_128K;
+				ret = 0;
+			}
+		} else {
+			ret = dt_device_get_address(dev_to_dt(pdev), num,
+						    &res.addr, &res.size);
+		}
+
+		return ((ret) ? NULL : &res);
+
+	case IORESOURCE_IRQ:
+		ret = platform_get_irq(dev_to_dt(pdev), num);
+
+		if (ret < 0)
+			return NULL;
+
+		res.addr = ret;
+		res.size = 1;
+
+		return &res;
+
+	default:
+		return NULL;
+	}
+}
+
+static int platform_get_irq_byname(struct platform_device *pdev, const char *name)
+{
+	const struct dt_property *dtprop;
+	struct acpi_iort_node *iort_node;
+	struct acpi_iort_smmu_v3 *node_smmu_data;
+	int ret = 0;
+
+	if (pdev->type == DEV_ACPI) {
+		iort_node = pdev->acpi_node;
+		node_smmu_data = (struct acpi_iort_smmu_v3 *)iort_node->node_data;
+
+		if (node_smmu_data != NULL) {
+			if (!strcmp(name, "eventq"))
+				ret = node_smmu_data->event_gsiv;
+			else if (!strcmp(name, "priq"))
+				ret = node_smmu_data->pri_gsiv;
+			else if (!strcmp(name, "cmdq-sync"))
+				ret = node_smmu_data->sync_gsiv;
+			else if (!strcmp(name, "gerror"))
+				ret = node_smmu_data->gerr_gsiv;
+			else
+				ret = -EINVAL;
+		}
+	} else {
+		dtprop = dt_find_property(dev_to_dt(pdev), "interrupt-names", NULL);
+		if (!dtprop)
+			return -EINVAL;
+
+		if (!dtprop->value)
+			return -ENODATA;
+	}
+
+	return ret;
+}
+
+#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
+({ \
+	s_time_t deadline = NOW() + MICROSECS(timeout_us); \
+	for (;;) { \
+		(val) = op(addr); \
+		if (cond) \
+			break; \
+		if (NOW() > deadline) { \
+			(val) = op(addr); \
+			break; \
+		} \
+		cpu_relax(); \
+		udelay(sleep_us); \
+	} \
+	(cond) ? 0 : -ETIMEDOUT; \
+})
+
+#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
+	readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
+
+/* Xen: Helpers for IRQ functions */
+#define request_irq(irq, func, flags, name, dev) request_irq(irq, flags, func, name, dev)
+#define free_irq release_irq
+
+enum irqreturn {
+	IRQ_NONE	= (0 << 0),
+	IRQ_HANDLED	= (1 << 0),
+};
+
+typedef enum irqreturn irqreturn_t;
+
+/* Device logger functions */
+#define dev_print(dev, lvl, fmt, ...)						\
+	 printk(lvl "smmu: " fmt, ## __VA_ARGS__)
+
+#define dev_dbg(dev, fmt, ...) dev_print(dev, XENLOG_DEBUG, fmt, ## __VA_ARGS__)
+#define dev_notice(dev, fmt, ...) dev_print(dev, XENLOG_INFO, fmt, ## __VA_ARGS__)
+#define dev_warn(dev, fmt, ...) dev_print(dev, XENLOG_WARNING, fmt, ## __VA_ARGS__)
+#define dev_err(dev, fmt, ...) dev_print(dev, XENLOG_ERR, fmt, ## __VA_ARGS__)
+#define dev_info(dev, fmt, ...) dev_print(dev, XENLOG_INFO, fmt, ## __VA_ARGS__)
+
+#define dev_err_ratelimited(dev, fmt, ...)					\
+	 dev_print(dev, XENLOG_ERR, fmt, ## __VA_ARGS__)
+
+#define dev_name(dev) dt_node_full_name(dev_to_dt(dev))
+
+/* Alias to Xen allocation helpers */
+#define kfree xfree
+#define kmalloc(size, flags)		_xmalloc(size, sizeof(void *))
+#define kzalloc(size, flags)		_xzalloc(size, sizeof(void *))
+#define devm_kzalloc(dev, size, flags)	_xzalloc(size, sizeof(void *))
+#define kmalloc_array(size, n, flags)	_xmalloc_array(size, sizeof(void *), n)
+
+/* Compatibility defines */
+#undef WARN_ON
+#define WARN_ON(cond) (!!cond)
+#define WARN_ON_ONCE(cond) WARN_ON(cond)
+
+static void __iomem *devm_ioremap_resource(struct device *dev,
+					   struct resource *res)
+{
+	void __iomem *ptr;
+
+	if (!res || res->type != IORESOURCE_MEM) {
+		dev_err(dev, "Invalid resource\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	ptr = ioremap_nocache(res->addr, res->size);
+	if (!ptr) {
+		dev_err(dev,
+			"ioremap failed (addr 0x%"PRIx64" size 0x%"PRIx64")\n",
+			res->addr, res->size);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return ptr;
+}
+
+/* Xen: Dummy iommu_domain */
+struct iommu_domain {
+	/* Runtime SMMU configuration for this iommu_domain */
+	struct arm_smmu_domain		*priv;
+	unsigned int			type;
+
+	atomic_t ref;
+	/* Used to link iommu_domain contexts for a same domain.
+	 * There is at least one per-SMMU to used by the domain.
+	 */
+	struct list_head		list;
+};
+/* Xen: Domain type definitions. Not really needed for Xen, defining to port
+ * Linux code as-is
+ */
+#define IOMMU_DOMAIN_UNMANAGED 0
+#define IOMMU_DOMAIN_DMA 1
+#define IOMMU_DOMAIN_IDENTITY 2
+
+/* Xen: Describes information required for a Xen domain */
+struct arm_smmu_xen_domain {
+	spinlock_t			lock;
+	/* List of iommu domains associated to this domain */
+	struct list_head		iommu_domains;
+};
+
+/*
+ * Xen: Information about each device stored in dev->archdata.iommu
+ *
+ * The dev->archdata.iommu stores the iommu_domain (runtime configuration of
+ * the SMMU).
+ */
+struct arm_smmu_xen_device {
+	struct iommu_domain *domain;
+};
 
 /* MMIO registers */
 #define ARM_SMMU_IDR0			0x0
@@ -412,10 +650,12 @@
 #define MSI_IOVA_BASE			0x8000000
 #define MSI_IOVA_LENGTH			0x100000
 
+#if 0 /* Not applicable for Xen */
 static bool disable_bypass;
 module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_bypass,
 	"Disable bypass streams such that incoming transactions from devices that are not attached to an iommu domain will report an abort back to the device and will not be allowed to pass through the SMMU.");
+#endif
 
 enum pri_resp {
 	PRI_RESP_DENY,
@@ -423,6 +663,7 @@ enum pri_resp {
 	PRI_RESP_SUCC,
 };
 
+#if 0 /* Xen: No MSI support in this iteration */
 enum arm_smmu_msi_index {
 	EVTQ_MSI_INDEX,
 	GERROR_MSI_INDEX,
@@ -447,6 +688,7 @@ static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
 		ARM_SMMU_PRIQ_IRQ_CFG2,
 	},
 };
+#endif
 
 struct arm_smmu_cmdq_ent {
 	/* Common fields */
@@ -551,6 +793,8 @@ struct arm_smmu_s2_cfg {
 	u16				vmid;
 	u64				vttbr;
 	u64				vtcr;
+	/* Xen: Domain associated to this configuration */
+	struct domain			*domain;
 };
 
 struct arm_smmu_strtab_ent {
@@ -623,9 +867,20 @@ struct arm_smmu_device {
 	struct arm_smmu_strtab_cfg	strtab_cfg;
 
 	/* IOMMU core code handle */
-	struct iommu_device		iommu;
+	//struct iommu_device		iommu;
+
+	/* Xen: Need to keep a list of SMMU devices */
+	struct list_head                devices;
 };
 
+/* Xen: Keep a list of devices associated with this driver */
+static DEFINE_SPINLOCK(arm_smmu_devices_lock);
+static LIST_HEAD(arm_smmu_devices);
+/* Xen: Helper for finding a device using fwnode */
+static
+struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode);
+
+
 /* SMMU private data for each master */
 struct arm_smmu_master_data {
 	struct arm_smmu_device		*smmu;
@@ -642,7 +897,7 @@ enum arm_smmu_domain_stage {
 
 struct arm_smmu_domain {
 	struct arm_smmu_device		*smmu;
-	struct mutex			init_mutex; /* Protects smmu pointer */
+	mutex			init_mutex; /* Protects smmu pointer */
 
 	struct io_pgtable_ops		*pgtbl_ops;
 	spinlock_t			pgtbl_lock;
@@ -737,15 +992,16 @@ static void queue_inc_prod(struct arm_smmu_queue *q)
  */
 static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe)
 {
-	ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US);
+	s_time_t deadline = NOW() + MICROSECS(ARM_SMMU_POLL_TIMEOUT_US);
 
 	while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) {
-		if (ktime_compare(ktime_get(), timeout) > 0)
+
+		if (NOW() > deadline)
 			return -ETIMEDOUT;
 
-		if (wfe) {
+		if (wfe)
 			wfe();
-		} else {
+		else {
 			cpu_relax();
 			udelay(1);
 		}
@@ -931,7 +1187,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
 		dev_err_ratelimited(smmu->dev, "CMD_SYNC timeout\n");
 	spin_unlock_irqrestore(&smmu->cmdq.lock, flags);
 }
-
+#if 0
 /* Context descriptor manipulation functions */
 static u64 arm_smmu_cpu_tcr_to_cd(u64 tcr)
 {
@@ -974,7 +1230,7 @@ static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu,
 
 	cfg->cdptr[3] = cpu_to_le64(cfg->cd.mair << CTXDESC_CD_3_MAIR_SHIFT);
 }
-
+#endif
 /* Stream table manipulation functions */
 static void
 arm_smmu_write_strtab_l1_desc(__le64 *dst, struct arm_smmu_strtab_l1_desc *desc)
@@ -1044,7 +1300,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
 			ste_live = true;
 			break;
 		case STRTAB_STE_0_CFG_ABORT:
-			if (disable_bypass)
+			//No bypass override for Xen
 				break;
 		default:
 			BUG(); /* STE corruption */
@@ -1056,7 +1312,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
 
 	/* Bypass/fault */
 	if (!ste->assigned || !(ste->s1_cfg || ste->s2_cfg)) {
-		if (!ste->assigned && disable_bypass)
+		if (!ste->assigned)
 			val |= STRTAB_STE_0_CFG_ABORT;
 		else
 			val |= STRTAB_STE_0_CFG_BYPASS;
@@ -1135,16 +1391,20 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
 	void *strtab;
 	struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
 	struct arm_smmu_strtab_l1_desc *desc = &cfg->l1_desc[sid >> STRTAB_SPLIT];
+	u32 alignment = 0;
 
 	if (desc->l2ptr)
 		return 0;
 
-	size = 1 << (STRTAB_SPLIT + ilog2(STRTAB_STE_DWORDS) + 3);
+	size = 1 << (STRTAB_SPLIT + LOG_2(STRTAB_STE_DWORDS) + 3);
 	strtab = &cfg->strtab[(sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS];
 
 	desc->span = STRTAB_SPLIT + 1;
-	desc->l2ptr = dmam_alloc_coherent(smmu->dev, size, &desc->l2ptr_dma,
-					  GFP_KERNEL | __GFP_ZERO);
+
+	alignment = 1 << ((5 + (desc->span - 1)));
+	desc->l2ptr = _xzalloc(size, alignment);
+	desc->l2ptr_dma = virt_to_maddr(desc->l2ptr);
+
 	if (!desc->l2ptr) {
 		dev_err(smmu->dev,
 			"failed to allocate l2 stream table for SID %u\n",
@@ -1158,7 +1418,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
 }
 
 /* IRQ and event handlers */
-static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
+static void arm_smmu_evtq_thread(int irq, void *dev, struct cpu_user_regs *regs)
 {
 	int i;
 	struct arm_smmu_device *smmu = dev;
@@ -1186,7 +1446,6 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
 
 	/* Sync our overflow flag, as we believe we're up to speed */
 	q->cons = Q_OVF(q, q->prod) | Q_WRP(q, q->cons) | Q_IDX(q, q->cons);
-	return IRQ_HANDLED;
 }
 
 static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
@@ -1203,7 +1462,7 @@ static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 
 	dev_info(smmu->dev, "unexpected PRI request received:\n");
 	dev_info(smmu->dev,
-		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016llx\n",
+		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016lx\n",
 		 sid, ssid, grpid, last ? "L" : "",
 		 evt[0] & PRIQ_0_PERM_PRIV ? "" : "un",
 		 evt[0] & PRIQ_0_PERM_READ ? "R" : "",
@@ -1227,7 +1486,7 @@ static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 	}
 }
 
-static irqreturn_t arm_smmu_priq_thread(int irq, void *dev)
+static void arm_smmu_priq_thread(int irq, void *dev, struct cpu_user_regs *regs)
 {
 	struct arm_smmu_device *smmu = dev;
 	struct arm_smmu_queue *q = &smmu->priq.q;
@@ -1243,18 +1502,16 @@ static irqreturn_t arm_smmu_priq_thread(int irq, void *dev)
 
 	/* Sync our overflow flag, as we believe we're up to speed */
 	q->cons = Q_OVF(q, q->prod) | Q_WRP(q, q->cons) | Q_IDX(q, q->cons);
-	return IRQ_HANDLED;
 }
 
-static irqreturn_t arm_smmu_cmdq_sync_handler(int irq, void *dev)
+static void arm_smmu_cmdq_sync_handler(int irq, void *dev, struct cpu_user_regs *regs)
 {
 	/* We don't actually use CMD_SYNC interrupts for anything */
-	return IRQ_HANDLED;
 }
 
 static int arm_smmu_device_disable(struct arm_smmu_device *smmu);
 
-static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
+static void arm_smmu_gerror_handler(int irq, void *dev, struct cpu_user_regs *regs)
 {
 	u32 gerror, gerrorn, active;
 	struct arm_smmu_device *smmu = dev;
@@ -1264,7 +1521,7 @@ static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
 
 	active = gerror ^ gerrorn;
 	if (!(active & GERROR_ERR_MASK))
-		return IRQ_NONE; /* No errors pending */
+		return; /* No errors pending */
 
 	dev_warn(smmu->dev,
 		 "unexpected global error reported (0x%08x), this could be serious\n",
@@ -1286,7 +1543,7 @@ static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
 
 	if (active & GERROR_MSI_CMDQ_ABT_ERR) {
 		dev_warn(smmu->dev, "CMDQ MSI write aborted\n");
-		arm_smmu_cmdq_sync_handler(irq, smmu->dev);
+		arm_smmu_cmdq_sync_handler(irq, smmu->dev, NULL);
 	}
 
 	if (active & GERROR_PRIQ_ABT_ERR)
@@ -1299,7 +1556,6 @@ static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
 		arm_smmu_cmdq_skip_err(smmu);
 
 	writel(gerror, smmu->base + ARM_SMMU_GERRORN);
-	return IRQ_HANDLED;
 }
 
 /* IO_PGTABLE API */
@@ -1311,11 +1567,13 @@ static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
 	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
 }
 
+#if 0 /*Xen: Unused function */
 static void arm_smmu_tlb_sync(void *cookie)
 {
 	struct arm_smmu_domain *smmu_domain = cookie;
 	__arm_smmu_tlb_sync(smmu_domain->smmu);
 }
+#endif
 
 static void arm_smmu_tlb_inv_context(void *cookie)
 {
@@ -1336,6 +1594,7 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 	__arm_smmu_tlb_sync(smmu);
 }
 
+#if 0 /*Xen: Unused functionality */
 static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
 					  size_t granule, bool leaf, void *cookie)
 {
@@ -1362,7 +1621,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
 	} while (size -= granule);
 }
 
-static const struct iommu_gather_ops arm_smmu_gather_ops = {
+static struct iommu_gather_ops arm_smmu_gather_ops = {
 	.tlb_flush_all	= arm_smmu_tlb_inv_context,
 	.tlb_add_flush	= arm_smmu_tlb_inv_range_nosync,
 	.tlb_sync	= arm_smmu_tlb_sync,
@@ -1380,6 +1639,11 @@ static bool arm_smmu_capable(enum iommu_cap cap)
 		return false;
 	}
 }
+#endif
+/* Xen: Stub out DMA domain related functions */
+#define iommu_get_dma_cookie(dom) 0
+#define iommu_put_dma_cookie(dom) 0
+
 
 static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 {
@@ -1410,6 +1674,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 	return &smmu_domain->domain;
 }
 
+#if 0
 static int arm_smmu_bitmap_alloc(unsigned long *map, int span)
 {
 	int idx, size = 1 << span;
@@ -1427,36 +1692,20 @@ static void arm_smmu_bitmap_free(unsigned long *map, int idx)
 {
 	clear_bit(idx, map);
 }
+#endif
 
 static void arm_smmu_domain_free(struct iommu_domain *domain)
 {
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
-
-	iommu_put_dma_cookie(domain);
-	free_io_pgtable_ops(smmu_domain->pgtbl_ops);
-
-	/* Free the CD and ASID, if we allocated them */
-	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
-		struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
-
-		if (cfg->cdptr) {
-			dmam_free_coherent(smmu_domain->smmu->dev,
-					   CTXDESC_CD_DWORDS << 3,
-					   cfg->cdptr,
-					   cfg->cdptr_dma);
-
-			arm_smmu_bitmap_free(smmu->asid_map, cfg->cd.asid);
-		}
-	} else {
-		struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
-		if (cfg->vmid)
-			arm_smmu_bitmap_free(smmu->vmid_map, cfg->vmid);
-	}
+	/*
+	 * Xen: Remove the free functions that are not used and code related
+	 * to S1 translation. We just need to free the domain here.
+	 */
 
 	kfree(smmu_domain);
 }
 
+#if 0
 static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
@@ -1488,33 +1737,30 @@ out_free_asid:
 	arm_smmu_bitmap_free(smmu->asid_map, asid);
 	return ret;
 }
+#endif
 
-static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
-				       struct io_pgtable_cfg *pgtbl_cfg)
+static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain)
 {
-	int vmid;
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
 
-	vmid = arm_smmu_bitmap_alloc(smmu->vmid_map, smmu->vmid_bits);
-	if (vmid < 0)
-		return vmid;
+	/* Xen: Set the values as needed */
 
-	cfg->vmid	= (u16)vmid;
-	cfg->vttbr	= pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
-	cfg->vtcr	= pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
+	cfg->vmid	= cfg->domain->arch.p2m.vmid;
+	cfg->vttbr	= page_to_maddr(cfg->domain->arch.p2m.root);
+	cfg->vtcr	= READ_SYSREG32(VTCR_EL2);
 	return 0;
 }
 
 static int arm_smmu_domain_finalise(struct iommu_domain *domain)
 {
 	int ret;
+#if 0	/* Xen: pgtbl_cfg not needed. So modify the function as needed */
 	unsigned long ias, oas;
 	enum io_pgtable_fmt fmt;
 	struct io_pgtable_cfg pgtbl_cfg;
 	struct io_pgtable_ops *pgtbl_ops;
-	int (*finalise_stage_fn)(struct arm_smmu_domain *,
-				 struct io_pgtable_cfg *);
+	int (*finalise_stage_fn)(struct arm_smmu_domain *);
+#endif
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 
@@ -1529,6 +1775,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)
 	if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S2))
 		smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
 
+#if 0
 	switch (smmu_domain->stage) {
 	case ARM_SMMU_DOMAIN_S1:
 		ias = VA_BITS;
@@ -1563,10 +1810,11 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)
 	domain->geometry.aperture_end = (1UL << ias) - 1;
 	domain->geometry.force_aperture = true;
 	smmu_domain->pgtbl_ops = pgtbl_ops;
-
 	ret = finalise_stage_fn(smmu_domain, &pgtbl_cfg);
 	if (ret < 0)
 		free_io_pgtable_ops(pgtbl_ops);
+#endif
+	ret = arm_smmu_domain_finalise_s2(smmu_domain);
 
 	return ret;
 }
@@ -1660,7 +1908,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
 		ste->s1_cfg = &smmu_domain->s1_cfg;
 		ste->s2_cfg = NULL;
-		arm_smmu_write_ctx_desc(smmu, ste->s1_cfg);
+		/*Xen: S1 configuratio not needed */
+		//arm_smmu_write_ctx_desc(smmu, ste->s1_cfg);
 	} else {
 		ste->s1_cfg = NULL;
 		ste->s2_cfg = &smmu_domain->s2_cfg;
@@ -1672,6 +1921,7 @@ out_unlock:
 	return ret;
 }
 
+#if 0
 static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
 			phys_addr_t paddr, size_t size, int prot)
 {
@@ -1737,11 +1987,13 @@ static int arm_smmu_match_node(struct device *dev, void *data)
 static
 struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
 {
+	/* Xen; Function modified as needed for Xen.*/
 	struct device *dev = driver_find_device(&arm_smmu_driver.driver, NULL,
 						fwnode, arm_smmu_match_node);
 	put_device(dev);
 	return dev ? dev_get_drvdata(dev) : NULL;
 }
+#endif
 
 static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
 {
@@ -1752,8 +2004,9 @@ static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
 
 	return sid < limit;
 }
-
+#if 0
 static struct iommu_ops arm_smmu_ops;
+#endif
 
 static int arm_smmu_add_device(struct device *dev)
 {
@@ -1761,9 +2014,9 @@ static int arm_smmu_add_device(struct device *dev)
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_master_data *master;
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
-	struct iommu_group *group;
 
-	if (!fwspec || fwspec->ops != &arm_smmu_ops)
+	/* Xen: fwspec->ops are not needed */
+	if (!fwspec)
 		return -ENODEV;
 	/*
 	 * We _can_ actually withstand dodgy bus code re-calling add_device()
@@ -1800,6 +2053,12 @@ static int arm_smmu_add_device(struct device *dev)
 		}
 	}
 
+#if 0
+/*
+ * Xen: Do not need an iommu group as the stream data is carried by the SMMU
+ * master device object
+ */
+
 	group = iommu_group_get_for_dev(dev);
 	if (!IS_ERR(group)) {
 		iommu_group_put(group);
@@ -1807,8 +2066,16 @@ static int arm_smmu_add_device(struct device *dev)
 	}
 
 	return PTR_ERR_OR_ZERO(group);
+#endif
+	return 0;
 }
 
+/*
+ * Xen: We can potentially support this function and destroy a device. This
+ * will be relevant for PCI hotplug. So, will be implemented as needed after
+ * passthrough support is available.
+ */
+#if 0
 static void arm_smmu_remove_device(struct device *dev)
 {
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
@@ -1944,7 +2211,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.put_resv_regions	= arm_smmu_put_resv_regions,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 };
-
+#endif
 /* Probing and initialisation functions */
 static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
 				   struct arm_smmu_queue *q,
@@ -1954,7 +2221,12 @@ static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
 {
 	size_t qsz = ((1 << q->max_n_shift) * dwords) << 3;
 
-	q->base = dmam_alloc_coherent(smmu->dev, qsz, &q->base_dma, GFP_KERNEL);
+	/* The SMMU cache coherency property is always set. Since we are sharing the CPU translation tables
+	 * just make a regular allocation.
+	 */
+	q->base = _xzalloc(qsz, sizeof(void *));
+	q->base_dma = virt_to_maddr(q->base);
+
 	if (!q->base) {
 		dev_err(smmu->dev, "failed to allocate queue (0x%zx bytes)\n",
 			qsz);
@@ -2025,10 +2297,11 @@ static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu)
 	void *strtab;
 	u64 reg;
 	u32 size, l1size;
+	u32 alignment;
 	struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
 
 	/* Calculate the L1 size, capped to the SIDSIZE. */
-	size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3);
+	size = STRTAB_L1_SZ_SHIFT - (LOG_2(STRTAB_L1_DESC_DWORDS) + 3);
 	size = min(size, smmu->sid_bits - STRTAB_SPLIT);
 	cfg->num_l1_ents = 1 << size;
 
@@ -2039,8 +2312,13 @@ static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu)
 			 size, smmu->sid_bits);
 
 	l1size = cfg->num_l1_ents * (STRTAB_L1_DESC_DWORDS << 3);
-	strtab = dmam_alloc_coherent(smmu->dev, l1size, &cfg->strtab_dma,
-				     GFP_KERNEL | __GFP_ZERO);
+
+	alignment = max_t(u32, cfg->num_l1_ents, 64);
+	//strtab = _xzalloc(l1size, sizeof(void *));
+	strtab = _xzalloc(l1size, l1size);
+	cfg->strtab_dma = virt_to_maddr(strtab);
+
+	//dsb(sy);
 	if (!strtab) {
 		dev_err(smmu->dev,
 			"failed to allocate l1 stream table (%u bytes)\n",
@@ -2068,8 +2346,9 @@ static int arm_smmu_init_strtab_linear(struct arm_smmu_device *smmu)
 	struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
 
 	size = (1 << smmu->sid_bits) * (STRTAB_STE_DWORDS << 3);
-	strtab = dmam_alloc_coherent(smmu->dev, size, &cfg->strtab_dma,
-				     GFP_KERNEL | __GFP_ZERO);
+	strtab = _xzalloc(size, size);
+	cfg->strtab_dma = virt_to_maddr(strtab);
+
 	if (!strtab) {
 		dev_err(smmu->dev,
 			"failed to allocate linear stream table (%u bytes)\n",
@@ -2152,6 +2431,8 @@ static int arm_smmu_update_gbpa(struct arm_smmu_device *smmu, u32 set, u32 clr)
 					  1, ARM_SMMU_POLL_TIMEOUT_US);
 }
 
+/* Xen: There is no MSI support as yet */
+#if 0
 static void arm_smmu_free_msis(void *data)
 {
 	struct device *dev = data;
@@ -2217,7 +2498,7 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
 	/* Add callback to free MSIs on teardown */
 	devm_add_action(dev, arm_smmu_free_msis, dev);
 }
-
+#endif
 static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
 {
 	int ret, irq;
@@ -2231,31 +2512,31 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
 		return ret;
 	}
 
-	arm_smmu_setup_msis(smmu);
+	//arm_smmu_setup_msis(smmu);
 
 	/* Request interrupt lines */
 	irq = smmu->evtq.q.irq;
 	if (irq) {
-		ret = devm_request_threaded_irq(smmu->dev, irq, NULL,
-						arm_smmu_evtq_thread,
-						IRQF_ONESHOT,
-						"arm-smmu-v3-evtq", smmu);
+		irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
+		ret = request_irq(irq, arm_smmu_evtq_thread,
+						0, "arm-smmu-v3-evtq", smmu);
 		if (ret < 0)
 			dev_warn(smmu->dev, "failed to enable evtq irq\n");
 	}
 
 	irq = smmu->cmdq.q.irq;
 	if (irq) {
-		ret = devm_request_irq(smmu->dev, irq,
-				       arm_smmu_cmdq_sync_handler, 0,
-				       "arm-smmu-v3-cmdq-sync", smmu);
+		irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
+		ret = request_irq(irq, arm_smmu_cmdq_sync_handler,
+				0, "arm-smmu-v3-cmdq-sync", smmu);
 		if (ret < 0)
 			dev_warn(smmu->dev, "failed to enable cmdq-sync irq\n");
 	}
 
 	irq = smmu->gerr_irq;
 	if (irq) {
-		ret = devm_request_irq(smmu->dev, irq, arm_smmu_gerror_handler,
+		irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
+		ret = request_irq(irq, arm_smmu_gerror_handler,
 				       0, "arm-smmu-v3-gerror", smmu);
 		if (ret < 0)
 			dev_warn(smmu->dev, "failed to enable gerror irq\n");
@@ -2263,12 +2544,13 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
 
 	if (smmu->features & ARM_SMMU_FEAT_PRI) {
 		irq = smmu->priq.q.irq;
+		irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
 		if (irq) {
-			ret = devm_request_threaded_irq(smmu->dev, irq, NULL,
-							arm_smmu_priq_thread,
-							IRQF_ONESHOT,
-							"arm-smmu-v3-priq",
-							smmu);
+			ret = request_irq(irq,
+					  arm_smmu_priq_thread,
+					  0,
+					  "arm-smmu-v3-priq",
+					  smmu);
 			if (ret < 0)
 				dev_warn(smmu->dev,
 					 "failed to enable priq irq\n");
@@ -2400,7 +2682,7 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 
 
 	/* Enable the SMMU interface, or ensure bypass */
-	if (!bypass || disable_bypass) {
+	if (!bypass) {
 		enables |= CR0_SMMUEN;
 	} else {
 		ret = arm_smmu_update_gbpa(smmu, 0, GBPA_ABORT);
@@ -2488,8 +2770,11 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 		smmu->features |= ARM_SMMU_FEAT_STALLS;
 	}
 
+#if 0/* Xen: Do not enable Stage 1 translations */
+
 	if (reg & IDR0_S1P)
 		smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
+#endif
 
 	if (reg & IDR0_S2P)
 		smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
@@ -2562,10 +2847,12 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 	if (reg & IDR5_GRAN4K)
 		smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
 
+#if 0 /* Xen: SMMU ops do not have a pgsize_bitmap member for Xen */
 	if (arm_smmu_ops.pgsize_bitmap == -1UL)
 		arm_smmu_ops.pgsize_bitmap = smmu->pgsize_bitmap;
 	else
 		arm_smmu_ops.pgsize_bitmap |= smmu->pgsize_bitmap;
+#endif
 
 	/* Output address size */
 	switch (reg & IDR5_OAS_MASK << IDR5_OAS_SHIFT) {
@@ -2592,10 +2879,12 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 		smmu->oas = 48;
 	}
 
+#if 0 /* Xen: There is no support for DMA mask */
 	/* Set the DMA mask for our table walker */
 	if (dma_set_mask_and_coherent(smmu->dev, DMA_BIT_MASK(smmu->oas)))
 		dev_warn(smmu->dev,
 			 "failed to set DMA mask for table walker\n");
+#endif
 
 	smmu->ias = max(smmu->ias, smmu->oas);
 
@@ -2612,7 +2901,8 @@ static int arm_smmu_device_acpi_probe(struct platform_device *pdev,
 	struct device *dev = smmu->dev;
 	struct acpi_iort_node *node;
 
-	node = *(struct acpi_iort_node **)dev_get_platdata(dev);
+	/* Xen: Modification to get iort_node */
+	node = (struct acpi_iort_node *)dev->acpi_node;
 
 	/* Retrieve SMMUv3 specific data */
 	iort_smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
@@ -2633,7 +2923,7 @@ static inline int arm_smmu_device_acpi_probe(struct platform_device *pdev,
 static int arm_smmu_device_dt_probe(struct platform_device *pdev,
 				    struct arm_smmu_device *smmu)
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = pdev;
 	u32 cells;
 	int ret = -EINVAL;
 
@@ -2646,8 +2936,8 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
 
 	parse_driver_options(smmu);
 
-	if (of_dma_is_coherent(dev->of_node))
-		smmu->features |= ARM_SMMU_FEAT_COHERENCY;
+	/* Xen: Set the COHERNECY feature */
+	smmu->features |= ARM_SMMU_FEAT_COHERENCY;
 
 	return ret;
 }
@@ -2656,9 +2946,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 {
 	int irq, ret;
 	struct resource *res;
-	resource_size_t ioaddr;
+	/*Xen: Do not need to setup sysfs */
+	/* resource_size_t ioaddr;*/
 	struct arm_smmu_device *smmu;
-	struct device *dev = &pdev->dev;
+	struct device *dev = pdev;/* Xen: dev is ignored */
 	bool bypass;
 
 	smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
@@ -2674,7 +2965,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		dev_err(dev, "MMIO region too small (%pr)\n", res);
 		return -EINVAL;
 	}
-	ioaddr = res->start;
+	/*ioaddr = res->start;*/
 
 	smmu->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(smmu->base))
@@ -2719,13 +3010,15 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		return ret;
 
 	/* Record our private device structure */
-	platform_set_drvdata(pdev, smmu);
+	/* platform_set_drvdata(pdev, smmu); */
 
 	/* Reset the device */
 	ret = arm_smmu_device_reset(smmu, bypass);
 	if (ret)
 		return ret;
 
+/* Xen: Not creating an IOMMU device list for Xen */
+#if 0
 	/* And we're up. Go go go! */
 	ret = iommu_device_sysfs_add(&smmu->iommu, dev, NULL,
 				     "smmu3.%pa", &ioaddr);
@@ -2757,9 +3050,18 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		if (ret)
 			return ret;
 	}
+#endif
+	/*
+	 * Xen: Keep a list of all probed devices. This will be used to query
+	 * the smmu devices based on the fwnode.
+	 */
+	INIT_LIST_HEAD(&smmu->devices);
+	spin_lock(&arm_smmu_devices_lock);
+	list_add(&smmu->devices, &arm_smmu_devices);
+	spin_unlock(&arm_smmu_devices_lock);
 	return 0;
 }
-
+#if 0
 static int arm_smmu_device_remove(struct platform_device *pdev)
 {
 	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
@@ -2767,6 +3069,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 	arm_smmu_device_disable(smmu);
 	return 0;
 }
+#endif
+#define MODULE_DEVICE_TABLE(type, name)
+#define of_device_id dt_device_match
 
 static struct of_device_id arm_smmu_of_match[] = {
 	{ .compatible = "arm,smmu-v3", },
@@ -2774,6 +3079,7 @@ static struct of_device_id arm_smmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
+#if 0
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
 		.name		= "arm-smmu-v3",
@@ -2789,3 +3095,318 @@ IOMMU_OF_DECLARE(arm_smmuv3, "arm,smmu-v3", NULL);
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
 MODULE_LICENSE("GPL v2");
+
+#endif
+/***** Start of Xen specific code *****/
+
+static int __must_check arm_smmu_iotlb_flush_all(struct domain *d)
+{
+	struct arm_smmu_xen_domain *smmu_domain = dom_iommu(d)->arch.priv;
+	struct iommu_domain *cfg;
+
+	spin_lock(&smmu_domain->lock);
+	list_for_each_entry(cfg, &smmu_domain->iommu_domains, list) {
+		/*
+		 * Only invalidate the context when SMMU is present.
+		 * This is because the context initialization is delayed
+		 * until a master has been added.
+		 */
+		if (unlikely(!ACCESS_ONCE(cfg->priv->smmu)))
+			continue;
+		arm_smmu_tlb_inv_context(cfg->priv);
+	}
+	spin_unlock(&smmu_domain->lock);
+	return 0;
+}
+
+static int __must_check arm_smmu_iotlb_flush(struct domain *d,
+					     unsigned long gfn,
+					     unsigned int page_count)
+{
+	return arm_smmu_iotlb_flush_all(d);
+}
+
+static struct iommu_domain *arm_smmu_get_domain(struct domain *d,
+						struct device *dev)
+{
+	struct iommu_domain *domain;
+	struct arm_smmu_xen_domain *xen_domain;
+	struct arm_smmu_device *smmu;
+	struct arm_smmu_domain *smmu_domain;
+
+	xen_domain = dom_iommu(d)->arch.priv;
+
+	smmu = arm_smmu_get_by_fwnode(dev->iommu_fwspec->iommu_fwnode);
+	if (!smmu)
+		return NULL;
+
+	/*
+	 * Loop through the &xen_domain->contexts to locate a context
+	 * assigned to this SMMU
+	 */
+	list_for_each_entry(domain, &xen_domain->iommu_domains, list) {
+		smmu_domain = to_smmu_domain(domain);
+		if (smmu_domain->smmu == smmu)
+			return domain;
+	}
+
+	return NULL;
+}
+
+static void arm_smmu_destroy_iommu_domain(struct iommu_domain *domain)
+{
+	list_del(&domain->list);
+	xfree(domain);
+}
+
+static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
+			       struct device *dev, u32 flag)
+{
+	int ret = 0;
+	struct iommu_domain *domain;
+	struct arm_smmu_xen_domain *xen_domain;
+	struct arm_smmu_domain *arm_smmu;
+
+	xen_domain = dom_iommu(d)->arch.priv;
+
+	if (!dev->archdata.iommu) {
+		dev->archdata.iommu = xzalloc(struct arm_smmu_xen_device);
+		if (!dev->archdata.iommu)
+			return -ENOMEM;
+	}
+
+	ret = arm_smmu_add_device(dev);
+	if (ret)
+		return ret;
+
+	spin_lock(&xen_domain->lock);
+
+	/*
+	 * Check to see if an iommu_domain already exists for this xen domain
+	 * under the same SMMU
+	 */
+	domain = arm_smmu_get_domain(d, dev);
+	if (!domain) {
+
+		domain = arm_smmu_domain_alloc(IOMMU_DOMAIN_DMA);
+		if (!domain) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		arm_smmu = to_smmu_domain(domain);
+		arm_smmu->s2_cfg.domain = d;
+
+		/* Chain the new context to the domain */
+		list_add(&domain->list, &xen_domain->iommu_domains);
+
+	}
+
+	ret = arm_smmu_attach_dev(domain, dev);
+	if (ret) {
+		if (domain->ref.counter == 0)
+			arm_smmu_destroy_iommu_domain(domain);
+	} else {
+		atomic_inc(&domain->ref);
+	}
+
+out:
+	spin_unlock(&xen_domain->lock);
+	return ret;
+}
+
+static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
+{
+	struct iommu_domain *domain = arm_smmu_get_domain(d, dev);
+	struct arm_smmu_xen_domain *xen_domain;
+	struct arm_smmu_domain *arm_smmu = to_smmu_domain(domain);
+
+	xen_domain = dom_iommu(d)->arch.priv;
+
+	if (!arm_smmu || arm_smmu->s2_cfg.domain != d) {
+		dev_err(dev, " not attached to domain %d\n", d->domain_id);
+		return -ESRCH;
+	}
+
+	spin_lock(&xen_domain->lock);
+
+	arm_smmu_detach_dev(dev);
+	atomic_dec(&domain->ref);
+
+	if (domain->ref.counter == 0)
+		arm_smmu_destroy_iommu_domain(domain);
+
+	spin_unlock(&xen_domain->lock);
+
+
+
+	return 0;
+}
+
+static int arm_smmu_reassign_dev(struct domain *s, struct domain *t,
+				 u8 devfn,  struct device *dev)
+{
+	int ret = 0;
+
+	/* Don't allow remapping on other domain than hwdom */
+	if (t && t != hardware_domain)
+		return -EPERM;
+
+	if (t == s)
+		return 0;
+
+	ret = arm_smmu_deassign_dev(s, dev);
+	if (ret)
+		return ret;
+
+	if (t) {
+		/* No flags are defined for ARM. */
+		ret = arm_smmu_assign_dev(t, devfn, dev, 0);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int arm_smmu_iommu_domain_init(struct domain *d)
+{
+	struct arm_smmu_xen_domain *xen_domain;
+
+	xen_domain = xzalloc(struct arm_smmu_xen_domain);
+	if (!xen_domain)
+		return -ENOMEM;
+
+	spin_lock_init(&xen_domain->lock);
+	INIT_LIST_HEAD(&xen_domain->iommu_domains);
+
+	dom_iommu(d)->arch.priv = xen_domain;
+
+	return 0;
+}
+
+static void __hwdom_init arm_smmu_iommu_hwdom_init(struct domain *d)
+{
+}
+
+static void arm_smmu_iommu_domain_teardown(struct domain *d)
+{
+	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
+
+	ASSERT(list_empty(&xen_domain->iommu_domains));
+	xfree(xen_domain);
+}
+
+static int __must_check arm_smmu_map_page(struct domain *d, unsigned long gfn,
+			unsigned long mfn, unsigned int flags)
+{
+	p2m_type_t t;
+
+	/*
+	 * Grant mappings can be used for DMA requests. The dev_bus_addr
+	 * returned by the hypercall is the MFN (not the IPA). For device
+	 * protected by an IOMMU, Xen needs to add a 1:1 mapping in the domain
+	 * p2m to allow DMA request to work.
+	 * This is only valid when the domain is directed mapped. Hence this
+	 * function should only be used by gnttab code with gfn == mfn.
+	 */
+	BUG_ON(!is_domain_direct_mapped(d));
+	BUG_ON(mfn != gfn);
+
+	/* We only support readable and writable flags */
+	if (!(flags & (IOMMUF_readable | IOMMUF_writable)))
+		return -EINVAL;
+
+	t = (flags & IOMMUF_writable) ? p2m_iommu_map_rw : p2m_iommu_map_ro;
+
+	/*
+	 * The function guest_physmap_add_entry replaces the current mapping
+	 * if there is already one...
+	 */
+	return guest_physmap_add_entry(d, _gfn(gfn), _mfn(mfn), 0, t);
+}
+
+static int __must_check arm_smmu_unmap_page(struct domain *d, unsigned long gfn)
+{
+	/*
+	 * This function should only be used by gnttab code when the domain
+	 * is direct mapped
+	 */
+	if (!is_domain_direct_mapped(d))
+		return -EINVAL;
+
+	return guest_physmap_remove_page(d, _gfn(gfn), _mfn(gfn), 0);
+}
+
+static const struct iommu_ops arm_smmu_iommu_ops = {
+	.init = arm_smmu_iommu_domain_init,
+	.hwdom_init = arm_smmu_iommu_hwdom_init,
+	.teardown = arm_smmu_iommu_domain_teardown,
+	.iotlb_flush = arm_smmu_iotlb_flush,
+	.iotlb_flush_all = arm_smmu_iotlb_flush_all,
+	.assign_device = arm_smmu_assign_dev,
+	.reassign_device = arm_smmu_reassign_dev,
+	.map_page = arm_smmu_map_page,
+	.unmap_page = arm_smmu_unmap_page,
+};
+
+static
+struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct arm_smmu_device *smmu = NULL;
+
+	spin_lock(&arm_smmu_devices_lock);
+	list_for_each_entry(smmu, &arm_smmu_devices, devices) {
+		if (smmu->dev->fwnode == fwnode)
+			break;
+	}
+	spin_unlock(&arm_smmu_devices_lock);
+
+	return smmu;
+}
+
+static __init int arm_smmu_dt_init(struct dt_device_node *dev,
+				   const void *data)
+{
+	int rc;
+
+	/*
+	 * Even if the device can't be initialized, we don't want to
+	 * give the SMMU device to dom0.
+	 */
+	dt_device_set_used_by(dev, DOMID_XEN);
+
+	rc = arm_smmu_device_probe(dt_to_dev(dev));
+	if (rc)
+		return rc;
+
+	iommu_set_ops(&arm_smmu_iommu_ops);
+
+	return 0;
+}
+
+DT_DEVICE_START(smmuv3, "ARM SMMU V3", DEVICE_IOMMU)
+	.dt_match = arm_smmu_of_match,
+	.init = arm_smmu_dt_init,
+DT_DEVICE_END
+
+#ifdef CONFIG_ACPI
+/* Set up the IOMMU */
+static int __init arm_smmu_acpi_init(const void *data)
+{
+	int rc;
+	rc = arm_smmu_device_probe((struct device *)data);
+
+	if (rc)
+		return rc;
+
+	iommu_set_ops(&arm_smmu_iommu_ops);
+	return 0;
+}
+
+ACPI_DEVICE_START(asmmuv3, "ARM SMMU V3", DEVICE_IOMMU)
+	.class_type = ACPI_IORT_NODE_SMMU_V3,
+	.init = arm_smmu_acpi_init,
+ACPI_DEVICE_END
+
+#endif
