[PATCH v4 0/6] Add support for ACPI VIOT

@@ -526,6 +526,9 @@ endif
 
 source "drivers/acpi/pmic/Kconfig"
 
+config ACPI_VIOT
+	bool
+
 endif	# ACPI
 
 config X86_PM_TIMER

@@ -403,6 +403,7 @@ config VIRTIO_IOMMU
 	depends on ARM64
 	select IOMMU_API
 	select INTERVAL_TREE
+	select ACPI_VIOT if ACPI
 	help
 	  Para-virtualised IOMMU driver with virtio.
 

@@ -118,3 +118,5 @@ video-objs			+= acpi_video.o video_detect.o
 obj-y				+= dptf/
 
 obj-$(CONFIG_ARM64)		+= arm64/
+
+obj-$(CONFIG_ACPI_VIOT)		+= viot.o

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ACPI_VIOT_H__
+#define __ACPI_VIOT_H__
+
+#include <linux/acpi.h>
+
+#ifdef CONFIG_ACPI_VIOT
+void __init acpi_viot_init(void);
+int viot_iommu_configure(struct device *dev);
+#else
+static inline void acpi_viot_init(void) {}
+static inline int viot_iommu_configure(struct device *dev)
+{
+	return -ENODEV;
+}
+#endif
+
+#endif /* __ACPI_VIOT_H__ */

@@ -27,6 +27,7 @@
 #include <linux/dmi.h>
 #endif
 #include <linux/acpi_iort.h>
+#include <linux/acpi_viot.h>
 #include <linux/pci.h>
 #include <acpi/apei.h>
 #include <linux/suspend.h>

@@ -1339,6 +1340,7 @@ static int __init acpi_init(void)
 	pci_mmcfg_late_init();
 	acpi_iort_init();
 	acpi_scan_init();
+	acpi_viot_init();
 	acpi_ec_init();
 	acpi_debugfs_init();
 	acpi_sleep_proc_init();

@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/acpi.h>
 #include <linux/acpi_iort.h>
+#include <linux/acpi_viot.h>
 #include <linux/iommu.h>
 #include <linux/signal.h>
 #include <linux/kthread.h>

@@ -1556,6 +1557,8 @@ static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
 		return ops;
 
 	err = iort_iommu_configure_id(dev, id_in);
+	if (err && err != -EPROBE_DEFER)
+		err = viot_iommu_configure(dev);
 
 	/*
 	 * If we have reason to believe the IOMMU driver missed the initial

@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtual I/O topology
+ *
+ * The Virtual I/O Translation Table (VIOT) describes the topology of
+ * para-virtual IOMMUs and the endpoints they manage. The OS uses it to
+ * initialize devices in the right order, preventing endpoints from issuing DMA
+ * before their IOMMU is ready.
+ *
+ * When binding a driver to a device, before calling the device driver's probe()
+ * method, the driver infrastructure calls dma_configure(). At that point the
+ * VIOT driver looks for an IOMMU associated to the device in the VIOT table.
+ * If an IOMMU exists and has been initialized, the VIOT driver initializes the
+ * device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU
+ * ops when the device driver configures DMA mappings. If an IOMMU exists and
+ * hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing
+ * the device until the IOMMU is available.
+ */
+#define pr_fmt(fmt) "ACPI: VIOT: " fmt
+
+#include <linux/acpi_viot.h>
+#include <linux/dma-iommu.h>
+#include <linux/fwnode.h>
+#include <linux/iommu.h>
+#include <linux/list.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+
+struct viot_iommu {
+	/* Node offset within the table */
+	unsigned int			offset;
+	struct fwnode_handle		*fwnode;
+	struct list_head		list;
+};
+
+struct viot_endpoint {
+	union {
+		/* PCI range */
+		struct {
+			u16		segment_start;
+			u16		segment_end;
+			u16		bdf_start;
+			u16		bdf_end;
+		};
+		/* MMIO */
+		u64			address;
+	};
+	u32				endpoint_id;
+	struct viot_iommu		*viommu;
+	struct list_head		list;
+};
+
+static struct acpi_table_viot *viot;
+static LIST_HEAD(viot_iommus);
+static LIST_HEAD(viot_pci_ranges);
+static LIST_HEAD(viot_mmio_endpoints);
+
+static int __init viot_check_bounds(const struct acpi_viot_header *hdr)
+{
+	struct acpi_viot_header *start, *end, *hdr_end;
+
+	start = ACPI_ADD_PTR(struct acpi_viot_header, viot,
+			     max_t(size_t, sizeof(*viot), viot->node_offset));
+	end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length);
+	hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr));
+
+	if (hdr < start || hdr_end > end) {
+		pr_err(FW_BUG "Node pointer overflows\n");
+		return -EOVERFLOW;
+	}
+	if (hdr->length < sizeof(*hdr)) {
+		pr_err(FW_BUG "Empty node\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu,
+					    u16 segment, u16 bdf)
+{
+	struct pci_dev *pdev;
+	struct fwnode_handle *fwnode;
+
+	pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf),
+					   bdf & 0xff);
+	if (!pdev) {
+		pr_err("Could not find PCI IOMMU\n");
+		return -ENODEV;
+	}
+
+	fwnode = pdev->dev.fwnode;
+	if (!fwnode) {
+		/*
+		 * PCI devices aren't necessarily described by ACPI. Create a
+		 * fwnode so the IOMMU subsystem can identify this device.
+		 */
+		fwnode = acpi_alloc_fwnode_static();
+		if (!fwnode) {
+			pci_dev_put(pdev);
+			return -ENOMEM;
+		}
+		set_primary_fwnode(&pdev->dev, fwnode);
+	}
+	viommu->fwnode = pdev->dev.fwnode;
+	pci_dev_put(pdev);
+	return 0;
+}
+
+static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu,
+					     u64 address)
+{
+	struct acpi_device *adev;
+	struct resource res = {
+		.start	= address,
+		.end	= address,
+		.flags	= IORESOURCE_MEM,
+	};
+
+	adev = acpi_resource_consumer(&res);
+	if (!adev) {
+		pr_err("Could not find MMIO IOMMU\n");
+		return -EINVAL;
+	}
+	viommu->fwnode = &adev->fwnode;
+	return 0;
+}
+
+static struct viot_iommu * __init viot_get_iommu(unsigned int offset)
+{
+	int ret;
+	struct viot_iommu *viommu;
+	struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header,
+						    viot, offset);
+	union {
+		struct acpi_viot_virtio_iommu_pci pci;
+		struct acpi_viot_virtio_iommu_mmio mmio;
+	} *node = (void *)hdr;
+
+	list_for_each_entry(viommu, &viot_iommus, list)
+		if (viommu->offset == offset)
+			return viommu;
+
+	if (viot_check_bounds(hdr))
+		return NULL;
+
+	viommu = kzalloc(sizeof(*viommu), GFP_KERNEL);
+	if (!viommu)
+		return NULL;
+
+	viommu->offset = offset;
+	switch (hdr->type) {
+	case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI:
+		if (hdr->length < sizeof(node->pci))
+			goto err_free;
+
+		ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment,
+						node->pci.bdf);
+		break;
+	case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO:
+		if (hdr->length < sizeof(node->mmio))
+			goto err_free;
+
+		ret = viot_get_mmio_iommu_fwnode(viommu,
+						 node->mmio.base_address);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	if (ret)
+		goto err_free;
+
+	list_add(&viommu->list, &viot_iommus);
+	return viommu;
+
+err_free:
+	kfree(viommu);
+	return NULL;
+}
+
+static int __init viot_parse_node(const struct acpi_viot_header *hdr)
+{
+	int ret = -EINVAL;
+	struct list_head *list;
+	struct viot_endpoint *ep;
+	union {
+		struct acpi_viot_mmio mmio;
+		struct acpi_viot_pci_range pci;
+	} *node = (void *)hdr;
+
+	if (viot_check_bounds(hdr))
+		return -EINVAL;
+
+	if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI ||
+	    hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO)
+		return 0;
+
+	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
+	if (!ep)
+		return -ENOMEM;
+
+	switch (hdr->type) {
+	case ACPI_VIOT_NODE_PCI_RANGE:
+		if (hdr->length < sizeof(node->pci)) {
+			pr_err(FW_BUG "Invalid PCI node size\n");
+			goto err_free;
+		}
+
+		ep->segment_start = node->pci.segment_start;
+		ep->segment_end = node->pci.segment_end;
+		ep->bdf_start = node->pci.bdf_start;
+		ep->bdf_end = node->pci.bdf_end;
+		ep->endpoint_id = node->pci.endpoint_start;
+		ep->viommu = viot_get_iommu(node->pci.output_node);
+		list = &viot_pci_ranges;
+		break;
+	case ACPI_VIOT_NODE_MMIO:
+		if (hdr->length < sizeof(node->mmio)) {
+			pr_err(FW_BUG "Invalid MMIO node size\n");
+			goto err_free;
+		}
+
+		ep->address = node->mmio.base_address;
+		ep->endpoint_id = node->mmio.endpoint;
+		ep->viommu = viot_get_iommu(node->mmio.output_node);
+		list = &viot_mmio_endpoints;
+		break;
+	default:
+		pr_warn("Unsupported node %x\n", hdr->type);
+		ret = 0;
+		goto err_free;
+	}
+
+	/*
+	 * To be compatible with future versions of the table which may include
+	 * other node types, keep parsing.
+	 */
+	if (!ep->viommu) {
+		pr_warn("No IOMMU node found\n");
+		ret = 0;
+		goto err_free;
+	}
+
+	list_add(&ep->list, list);
+	return 0;
+
+err_free:
+	kfree(ep);
+	return ret;
+}
+
+/**
+ * acpi_viot_init - Parse the VIOT table
+ *
+ * Parse the VIOT table, prepare the list of endpoints to be used during DMA
+ * setup of devices.
+ */
+void __init acpi_viot_init(void)
+{
+	int i;
+	acpi_status status;
+	struct acpi_table_header *hdr;
+	struct acpi_viot_header *node;
+
+	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
+	if (ACPI_FAILURE(status)) {
+		if (status != AE_NOT_FOUND) {
+			const char *msg = acpi_format_exception(status);
+
+			pr_err("Failed to get table, %s\n", msg);
+		}
+		return;
+	}
+
+	viot = (void *)hdr;
+
+	node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset);
+	for (i = 0; i < viot->node_count; i++) {
+		if (viot_parse_node(node))
+			return;
+
+		node = ACPI_ADD_PTR(struct acpi_viot_header, node,
+				    node->length);
+	}
+}
+
+static int viot_dev_iommu_init(struct device *dev, struct viot_iommu *viommu,
+			       u32 epid)
+{
+	const struct iommu_ops *ops;
+
+	if (!viommu)
+		return -ENODEV;
+
+	/* We're not translating ourself */
+	if (viommu->fwnode == dev->fwnode)
+		return -EINVAL;
+
+	ops = iommu_ops_from_fwnode(viommu->fwnode);
+	if (!ops)
+		return IS_ENABLED(CONFIG_VIRTIO_IOMMU) ?
+			-EPROBE_DEFER : -ENODEV;
+
+	return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode, ops);
+}
+
+static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
+{
+	u32 epid;
+	struct viot_endpoint *ep;
+	u32 domain_nr = pci_domain_nr(pdev->bus);
+
+	list_for_each_entry(ep, &viot_pci_ranges, list) {
+		if (domain_nr >= ep->segment_start &&
+		    domain_nr <= ep->segment_end &&
+		    dev_id >= ep->bdf_start &&
+		    dev_id <= ep->bdf_end) {
+			epid = ((domain_nr - ep->segment_start) << 16) +
+				dev_id - ep->bdf_start + ep->endpoint_id;
+
+			/*
+			 * If we found a PCI range managed by the viommu, we're
+			 * the one that has to request ACS.
+			 */
+			pci_request_acs();
+
+			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
+						   epid);
+		}
+	}
+	return -ENODEV;
+}
+
+static int viot_mmio_dev_iommu_init(struct platform_device *pdev)
+{
+	struct resource *mem;
+	struct viot_endpoint *ep;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem)
+		return -ENODEV;
+
+	list_for_each_entry(ep, &viot_mmio_endpoints, list) {
+		if (ep->address == mem->start)
+			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
+						   ep->endpoint_id);
+	}
+	return -ENODEV;
+}
+
+/**
+ * viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT
+ * @dev: the endpoint
+ *
+ * Return: 0 on success, <0 on failure
+ */
+int viot_iommu_configure(struct device *dev)
+{
+	if (dev_is_pci(dev))
+		return pci_for_each_dma_alias(to_pci_dev(dev),
+					      viot_pci_dev_iommu_init, NULL);
+	else if (dev_is_platform(dev))
+		return viot_mmio_dev_iommu_init(to_platform_device(dev));
+	return -ENODEV;
+}

@@ -431,6 +431,14 @@ W:	https://01.org/linux-acpi
 B:	https://bugzilla.kernel.org
 F:	drivers/acpi/acpi_video.c
 
+ACPI VIOT DRIVER
+M:	Jean-Philippe Brucker <jean-philippe@linaro.org>
+L:	linux-acpi@vger.kernel.org
+L:	iommu@lists.linux-foundation.org
+S:	Maintained
+F:	drivers/acpi/viot.c
+F:	include/linux/acpi_viot.h
+
 ACPI WMI DRIVER
 L:	platform-driver-x86@vger.kernel.org
 S:	Orphan

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_ACPI_IORT) 	+= iort.o
 obj-$(CONFIG_ACPI_GTDT) 	+= gtdt.o
+obj-y				+= dma.o

@@ -259,9 +259,12 @@ void acpi_numa_x2apic_affinity_init(struct acpi_srat_x2apic_cpu_affinity *pa);
 
 #ifdef CONFIG_ARM64
 void acpi_numa_gicc_affinity_init(struct acpi_srat_gicc_affinity *pa);
+void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size);
 #else
 static inline void
 acpi_numa_gicc_affinity_init(struct acpi_srat_gicc_affinity *pa) { }
+static inline void
+acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size) { }
 #endif
 
 int acpi_numa_memory_affinity_init (struct acpi_srat_mem_affinity *ma);

@@ -34,7 +34,7 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 id,
 void acpi_configure_pmsi_domain(struct device *dev);
 int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id);
 /* IOMMU interface */
-void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *size);
+int iort_dma_get_ranges(struct device *dev, u64 *size);
 const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
 						const u32 *id_in);
 int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head);

@@ -48,8 +48,8 @@ static inline struct irq_domain *iort_get_device_domain(
 { return NULL; }
 static inline void acpi_configure_pmsi_domain(struct device *dev) { }
 /* IOMMU interface */
-static inline void iort_dma_setup(struct device *dev, u64 *dma_addr,
-				  u64 *size) { }
+static inline int iort_dma_get_ranges(struct device *dev, u64 *size)
+{ return -ENODEV; }
 static inline const struct iommu_ops *iort_iommu_configure_id(
 				      struct device *dev, const u32 *id_in)
 { return NULL; }

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/acpi.h>
+#include <linux/acpi_iort.h>
+#include <linux/device.h>
+#include <linux/dma-direct.h>
+
+void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
+{
+	int ret;
+	u64 end, mask;
+	u64 dmaaddr = 0, size = 0, offset = 0;
+
+	/*
+	 * If @dev is expected to be DMA-capable then the bus code that created
+	 * it should have initialised its dma_mask pointer by this point. For
+	 * now, we'll continue the legacy behaviour of coercing it to the
+	 * coherent mask if not, but we'll no longer do so quietly.
+	 */
+	if (!dev->dma_mask) {
+		dev_warn(dev, "DMA mask not set\n");
+		dev->dma_mask = &dev->coherent_dma_mask;
+	}
+
+	if (dev->coherent_dma_mask)
+		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
+	else
+		size = 1ULL << 32;
+
+	ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
+	if (ret == -ENODEV)
+		ret = iort_dma_get_ranges(dev, &size);
+	if (!ret) {
+		/*
+		 * Limit coherent and dma mask based on size retrieved from
+		 * firmware.
+		 */
+		end = dmaaddr + size - 1;
+		mask = DMA_BIT_MASK(ilog2(end) + 1);
+		dev->bus_dma_limit = end;
+		dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
+		*dev->dma_mask = min(*dev->dma_mask, mask);
+	}
+
+	*dma_addr = dmaaddr;
+	*dma_size = size;
+
+	ret = dma_direct_set_offset(dev, dmaaddr + offset, dmaaddr, size);
+
+	dev_dbg(dev, "dma_offset(%#08llx)%s\n", offset, ret ? " failed!" : "");
+}

@@ -1144,56 +1144,18 @@ static int rc_dma_get_range(struct device *dev, u64 *size)
 }
 
 /**
- * iort_dma_setup() - Set-up device DMA parameters.
+ * iort_dma_get_ranges() - Look up DMA addressing limit for the device
+ * @dev: device to lookup
+ * @size: DMA range size result pointer
  *
- * @dev: device to configure
- * @dma_addr: device DMA address result pointer
- * @dma_size: DMA range size result pointer
+ * Return: 0 on success, an error otherwise.
  */
-void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
+int iort_dma_get_ranges(struct device *dev, u64 *size)
 {
-	u64 end, mask, dmaaddr = 0, size = 0, offset = 0;
-	int ret;
-
-	/*
-	 * If @dev is expected to be DMA-capable then the bus code that created
-	 * it should have initialised its dma_mask pointer by this point. For
-	 * now, we'll continue the legacy behaviour of coercing it to the
-	 * coherent mask if not, but we'll no longer do so quietly.
-	 */
-	if (!dev->dma_mask) {
-		dev_warn(dev, "DMA mask not set\n");
-		dev->dma_mask = &dev->coherent_dma_mask;
-	}
-
-	if (dev->coherent_dma_mask)
-		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
+	if (dev_is_pci(dev))
+		return rc_dma_get_range(dev, size);
 	else
-		size = 1ULL << 32;
-
-	ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
-	if (ret == -ENODEV)
-		ret = dev_is_pci(dev) ? rc_dma_get_range(dev, &size)
-				      : nc_dma_get_range(dev, &size);
-
-	if (!ret) {
-		/*
-		 * Limit coherent and dma mask based on size retrieved from
-		 * firmware.
-		 */
-		end = dmaaddr + size - 1;
-		mask = DMA_BIT_MASK(ilog2(end) + 1);
-		dev->bus_dma_limit = end;
-		dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
-		*dev->dma_mask = min(*dev->dma_mask, mask);
-	}
-
-	*dma_addr = dmaaddr;
-	*dma_size = size;
-
-	ret = dma_direct_set_offset(dev, dmaaddr + offset, dmaaddr, size);
-
-	dev_dbg(dev, "dma_offset(%#08llx)%s\n", offset, ret ? " failed!" : "");
+		return nc_dma_get_range(dev, size);
 }
 
 static void __init acpi_iort_register_irq(int hwirq, const char *name,

@@ -1537,7 +1537,7 @@ int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,
 		return 0;
 	}
 
-	iort_dma_setup(dev, &dma_addr, &size);
+	acpi_arch_dma_setup(dev, &dma_addr, &size);
 
 	iommu = iort_iommu_configure_id(dev, input_id);
 	if (PTR_ERR(iommu) == -EPROBE_DEFER)

@@ -588,6 +588,9 @@ struct acpi_pci_root {
 
 bool acpi_dma_supported(struct acpi_device *adev);
 enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev);
+int acpi_iommu_fwspec_init(struct device *dev, u32 id,
+			   struct fwnode_handle *fwnode,
+			   const struct iommu_ops *ops);
 int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
 		       u64 *size);
 int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,

@@ -35,8 +35,7 @@ void acpi_configure_pmsi_domain(struct device *dev);
 int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id);
 /* IOMMU interface */
 int iort_dma_get_ranges(struct device *dev, u64 *size);
-const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
-						const u32 *id_in);
+int iort_iommu_configure_id(struct device *dev, const u32 *id_in);
 int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head);
 phys_addr_t acpi_iort_dma_get_max_cpu_address(void);
 #else

@@ -50,9 +49,8 @@ static inline void acpi_configure_pmsi_domain(struct device *dev) { }
 /* IOMMU interface */
 static inline int iort_dma_get_ranges(struct device *dev, u64 *size)
 { return -ENODEV; }
-static inline const struct iommu_ops *iort_iommu_configure_id(
-				      struct device *dev, const u32 *id_in)
-{ return NULL; }
+static inline int iort_iommu_configure_id(struct device *dev, const u32 *id_in)
+{ return -ENODEV; }
 static inline
 int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
 { return 0; }

@@ -806,23 +806,6 @@ static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
 	return NULL;
 }
 
-static inline const struct iommu_ops *iort_fwspec_iommu_ops(struct device *dev)
-{
-	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
-
-	return (fwspec && fwspec->ops) ? fwspec->ops : NULL;
-}
-
-static inline int iort_add_device_replay(struct device *dev)
-{
-	int err = 0;
-
-	if (dev->bus && !device_iommu_mapped(dev))
-		err = iommu_probe_device(dev);
-
-	return err;
-}
-
 /**
  * iort_iommu_msi_get_resv_regions - Reserved region driver helper
  * @dev: Device from iommu_get_resv_regions()

@@ -900,18 +883,6 @@ static inline bool iort_iommu_driver_enabled(u8 type)
 	}
 }
 
-static int arm_smmu_iort_xlate(struct device *dev, u32 streamid,
-			       struct fwnode_handle *fwnode,
-			       const struct iommu_ops *ops)
-{
-	int ret = iommu_fwspec_init(dev, fwnode, ops);
-
-	if (!ret)
-		ret = iommu_fwspec_add_ids(dev, &streamid, 1);
-
-	return ret;
-}
-
 static bool iort_pci_rc_supports_ats(struct acpi_iort_node *node)
 {
 	struct acpi_iort_root_complex *pci_rc;

@@ -946,7 +917,7 @@ static int iort_iommu_xlate(struct device *dev, struct acpi_iort_node *node,
 		return iort_iommu_driver_enabled(node->type) ?
 		       -EPROBE_DEFER : -ENODEV;
 
-	return arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops);
+	return acpi_iommu_fwspec_init(dev, streamid, iort_fwnode, ops);
 }
 
 struct iort_pci_alias_info {

@@ -1020,24 +991,14 @@ static int iort_nc_iommu_map_id(struct device *dev,
  * @dev: device to configure
  * @id_in: optional input id const value pointer
  *
- * Returns: iommu_ops pointer on configuration success
- *          NULL on configuration failure
+ * Returns: 0 on success, <0 on failure
  */
-const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
-						const u32 *id_in)
+int iort_iommu_configure_id(struct device *dev, const u32 *id_in)
 {
 	struct acpi_iort_node *node;
-	const struct iommu_ops *ops;
+	const struct iommu_ops *ops = NULL;
 	int err = -ENODEV;
 
-	/*
-	 * If we already translated the fwspec there
-	 * is nothing left to do, return the iommu_ops.
-	 */
-	ops = iort_fwspec_iommu_ops(dev);
-	if (ops)
-		return ops;
-
 	if (dev_is_pci(dev)) {
 		struct iommu_fwspec *fwspec;
 		struct pci_bus *bus = to_pci_dev(dev)->bus;

@@ -1046,7 +1007,7 @@ const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
 		node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
 				      iort_match_node_callback, &bus->dev);
 		if (!node)
-			return NULL;
+			return -ENODEV;
 
 		info.node = node;
 		err = pci_for_each_dma_alias(to_pci_dev(dev),

@@ -1059,7 +1020,7 @@ const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
 		node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
 				      iort_match_node_callback, dev);
 		if (!node)
-			return NULL;
+			return -ENODEV;
 
 		err = id_in ? iort_nc_iommu_map_id(dev, node, id_in) :
 			      iort_nc_iommu_map(dev, node);

@@ -1068,32 +1029,14 @@ const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
 			iort_named_component_init(dev, node);
 	}
 
-	/*
-	 * If we have reason to believe the IOMMU driver missed the initial
-	 * add_device callback for dev, replay it to get things in order.
-	 */
-	if (!err) {
-		ops = iort_fwspec_iommu_ops(dev);
-		err = iort_add_device_replay(dev);
-	}
-
-	/* Ignore all other errors apart from EPROBE_DEFER */
-	if (err == -EPROBE_DEFER) {
-		ops = ERR_PTR(err);
-	} else if (err) {
-		dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
-		ops = NULL;
-	}
-
-	return ops;
+	return err;
 }
 
 #else
 int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
 { return 0; }
-const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
-						const u32 *input_id)
-{ return NULL; }
+int iort_iommu_configure_id(struct device *dev, const u32 *input_id)
+{ return -ENODEV; }
 #endif
 
 static int nc_dma_get_range(struct device *dev, u64 *size)

@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/acpi.h>
 #include <linux/acpi_iort.h>
+#include <linux/iommu.h>
 #include <linux/signal.h>
 #include <linux/kthread.h>
 #include <linux/dmi.h>

@@ -1520,6 +1521,76 @@ int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
 	return ret >= 0 ? 0 : ret;
 }
 
+#ifdef CONFIG_IOMMU_API
+int acpi_iommu_fwspec_init(struct device *dev, u32 id,
+			   struct fwnode_handle *fwnode,
+			   const struct iommu_ops *ops)
+{
+	int ret = iommu_fwspec_init(dev, fwnode, ops);
+
+	if (!ret)
+		ret = iommu_fwspec_add_ids(dev, &id, 1);
+
+	return ret;
+}
+
+static inline const struct iommu_ops *acpi_iommu_fwspec_ops(struct device *dev)
+{
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
+	return fwspec ? fwspec->ops : NULL;
+}
+
+static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
+						       const u32 *id_in)
+{
+	int err;
+	const struct iommu_ops *ops;
+
+	/*
+	 * If we already translated the fwspec there is nothing left to do,
+	 * return the iommu_ops.
+	 */
+	ops = acpi_iommu_fwspec_ops(dev);
+	if (ops)
+		return ops;
+
+	err = iort_iommu_configure_id(dev, id_in);
+
+	/*
+	 * If we have reason to believe the IOMMU driver missed the initial
+	 * add_device callback for dev, replay it to get things in order.
+	 */
+	if (!err && dev->bus && !device_iommu_mapped(dev))
+		err = iommu_probe_device(dev);
+
+	/* Ignore all other errors apart from EPROBE_DEFER */
+	if (err == -EPROBE_DEFER) {
+		return ERR_PTR(err);
+	} else if (err) {
+		dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
+		return NULL;
+	}
+	return acpi_iommu_fwspec_ops(dev);
+}
+
+#else /* !CONFIG_IOMMU_API */
+
+int acpi_iommu_fwspec_init(struct device *dev, u32 id,
+			   struct fwnode_handle *fwnode,
+			   const struct iommu_ops *ops)
+{
+	return -ENODEV;
+}
+
+static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
+						       const u32 *id_in)
+{
+	return NULL;
+}
+
+#endif /* !CONFIG_IOMMU_API */
+
 /**
  * acpi_dma_configure_id - Set-up DMA configuration for the device.
  * @dev: The pointer to the device