// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2016, Semihalf
 *      Author: Tomasz Nowicki <tn@semihalf.com>
 *
 * This file implements early detection/parsing of I/O mapping
 * reported to OS through firmware via I/O Remapping Table (IORT)
 * IORT document number: ARM DEN 0049A
 */

#define pr_fmt(fmt)     "ACPI: IORT: " fmt

#include <linux/acpi_iort.h>
#include <linux/iommu.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define IORT_TYPE_MASK(type)    (1 << (type))
#define IORT_MSI_TYPE           (1 << ACPI_IORT_NODE_ITS_GROUP)
#define IORT_IOMMU_TYPE         ((1 << ACPI_IORT_NODE_SMMU) |   \
                                (1 << ACPI_IORT_NODE_SMMU_V3))

struct iort_its_msi_chip {
        struct list_head        list;
        struct fwnode_handle    *fw_node;
        phys_addr_t             base_addr;
        u32                     translation_id;
};

struct iort_fwnode {
        struct list_head list;
        struct acpi_iort_node *iort_node;
        struct fwnode_handle *fwnode;
};
static LIST_HEAD(iort_fwnode_list);
static DEFINE_SPINLOCK(iort_fwnode_lock);

/**
 * iort_set_fwnode() - Create iort_fwnode and use it to register
 *                     iommu data in the iort_fwnode_list
 *
 * @node: IORT table node associated with the IOMMU
 * @fwnode: fwnode associated with the IORT node
 *
 * Returns: 0 on success
 *          <0 on failure
 */
static inline int iort_set_fwnode(struct acpi_iort_node *iort_node,
                                  struct fwnode_handle *fwnode)
{
        struct iort_fwnode *np;

        np = kzalloc(sizeof(struct iort_fwnode), GFP_ATOMIC);

        if (WARN_ON(!np))
                return -ENOMEM;

        INIT_LIST_HEAD(&np->list);
        np->iort_node = iort_node;
        np->fwnode = fwnode;

        spin_lock(&iort_fwnode_lock);
        list_add_tail(&np->list, &iort_fwnode_list);
        spin_unlock(&iort_fwnode_lock);

        return 0;
}

/**
 * iort_get_fwnode() - Retrieve fwnode associated with an IORT node
 *
 * @node: IORT table node to be looked-up
 *
 * Returns: fwnode_handle pointer on success, NULL on failure
 */
static inline struct fwnode_handle *iort_get_fwnode(
                        struct acpi_iort_node *node)
{
        struct iort_fwnode *curr;
        struct fwnode_handle *fwnode = NULL;

        spin_lock(&iort_fwnode_lock);
        list_for_each_entry(curr, &iort_fwnode_list, list) {
                if (curr->iort_node == node) {
                        fwnode = curr->fwnode;
                        break;
                }
        }
        spin_unlock(&iort_fwnode_lock);

        return fwnode;
}

/**
 * iort_delete_fwnode() - Delete fwnode associated with an IORT node
 *
 * @node: IORT table node associated with fwnode to delete
 */
static inline void iort_delete_fwnode(struct acpi_iort_node *node)
{
        struct iort_fwnode *curr, *tmp;

        spin_lock(&iort_fwnode_lock);
        list_for_each_entry_safe(curr, tmp, &iort_fwnode_list, list) {
                if (curr->iort_node == node) {
                        list_del(&curr->list);
                        kfree(curr);
                        break;
                }
        }
        spin_unlock(&iort_fwnode_lock);
}

/**
 * iort_get_iort_node() - Retrieve iort_node associated with an fwnode
 *
 * @fwnode: fwnode associated with device to be looked-up
 *
 * Returns: iort_node pointer on success, NULL on failure
 */
static inline struct acpi_iort_node *iort_get_iort_node(
                        struct fwnode_handle *fwnode)
{
        struct iort_fwnode *curr;
        struct acpi_iort_node *iort_node = NULL;

        spin_lock(&iort_fwnode_lock);
        list_for_each_entry(curr, &iort_fwnode_list, list) {
                if (curr->fwnode == fwnode) {
                        iort_node = curr->iort_node;
                        break;
                }
        }
        spin_unlock(&iort_fwnode_lock);

        return iort_node;
}

typedef acpi_status (*iort_find_node_callback)
        (struct acpi_iort_node *node, void *context);

/* Root pointer to the mapped IORT table */
static struct acpi_table_header *iort_table;

static LIST_HEAD(iort_msi_chip_list);
static DEFINE_SPINLOCK(iort_msi_chip_lock);

/**
 * iort_register_domain_token() - register domain token along with related
 * ITS ID and base address to the list from where we can get it back later on.
 * @trans_id: ITS ID.
 * @base: ITS base address.
 * @fw_node: Domain token.
 *
 * Returns: 0 on success, -ENOMEM if no memory when allocating list element
 */
int iort_register_domain_token(int trans_id, phys_addr_t base,
                               struct fwnode_handle *fw_node)
{
        struct iort_its_msi_chip *its_msi_chip;

        its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
        if (!its_msi_chip)
                return -ENOMEM;

        its_msi_chip->fw_node = fw_node;
        its_msi_chip->translation_id = trans_id;
        its_msi_chip->base_addr = base;

        spin_lock(&iort_msi_chip_lock);
        list_add(&its_msi_chip->list, &iort_msi_chip_list);
        spin_unlock(&iort_msi_chip_lock);

        return 0;
}

/**
 * iort_deregister_domain_token() - Deregister domain token based on ITS ID
 * @trans_id: ITS ID.
 *
 * Returns: none.
 */
void iort_deregister_domain_token(int trans_id)
{
        struct iort_its_msi_chip *its_msi_chip, *t;

        spin_lock(&iort_msi_chip_lock);
        list_for_each_entry_safe(its_msi_chip, t, &iort_msi_chip_list, list) {
                if (its_msi_chip->translation_id == trans_id) {
                        list_del(&its_msi_chip->list);
                        kfree(its_msi_chip);
                        break;
                }
        }
        spin_unlock(&iort_msi_chip_lock);
}

/**
 * iort_find_domain_token() - Find domain token based on given ITS ID
 * @trans_id: ITS ID.
 *
 * Returns: domain token when find on the list, NULL otherwise
 */
struct fwnode_handle *iort_find_domain_token(int trans_id)
{
        struct fwnode_handle *fw_node = NULL;
        struct iort_its_msi_chip *its_msi_chip;

        spin_lock(&iort_msi_chip_lock);
        list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
                if (its_msi_chip->translation_id == trans_id) {
                        fw_node = its_msi_chip->fw_node;
                        break;
                }
        }
        spin_unlock(&iort_msi_chip_lock);

        return fw_node;
}

static struct acpi_iort_node *iort_scan_node(enum acpi_iort_node_type type,
                                             iort_find_node_callback callback,
                                             void *context)
{
        struct acpi_iort_node *iort_node, *iort_end;
        struct acpi_table_iort *iort;
        int i;

        if (!iort_table)
                return NULL;

        /* Get the first IORT node */
        iort = (struct acpi_table_iort *)iort_table;
        iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
                                 iort->node_offset);
        iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
                                iort_table->length);

        for (i = 0; i < iort->node_count; i++) {
                if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND,
                               "IORT node pointer overflows, bad table!\n"))
                        return NULL;

                if (iort_node->type == type &&
                    ACPI_SUCCESS(callback(iort_node, context)))
                        return iort_node;

                iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
                                         iort_node->length);
        }

        return NULL;
}

static acpi_status iort_match_node_callback(struct acpi_iort_node *node,
                                            void *context)
{
        struct device *dev = context;
        acpi_status status = AE_NOT_FOUND;

        if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT) {
                struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
                struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
                struct acpi_iort_named_component *ncomp;

                if (!adev)
                        goto out;

                status = acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &buf);
                if (ACPI_FAILURE(status)) {
                        dev_warn(dev, "Can't get device full path name\n");
                        goto out;
                }

                ncomp = (struct acpi_iort_named_component *)node->node_data;
                status = !strcmp(ncomp->device_name, buf.pointer) ?
                                                        AE_OK : AE_NOT_FOUND;
                acpi_os_free(buf.pointer);
        } else if (node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
                struct acpi_iort_root_complex *pci_rc;
                struct pci_bus *bus;

                bus = to_pci_bus(dev);
                pci_rc = (struct acpi_iort_root_complex *)node->node_data;

                /*
                 * It is assumed that PCI segment numbers maps one-to-one
                 * with root complexes. Each segment number can represent only
                 * one root complex.
                 */
                status = pci_rc->pci_segment_number == pci_domain_nr(bus) ?
                                                        AE_OK : AE_NOT_FOUND;
        }
out:
        return status;
}

static int iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in,
                       u32 *rid_out)
{
        /* Single mapping does not care for input id */
        if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
                if (type == ACPI_IORT_NODE_NAMED_COMPONENT ||
                    type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
                        *rid_out = map->output_base;
                        return 0;
                }

                pr_warn(FW_BUG "[map %p] SINGLE MAPPING flag not allowed for node type %d, skipping ID map\n",
                        map, type);
                return -ENXIO;
        }

        if (rid_in < map->input_base ||
            (rid_in >= map->input_base + map->id_count))
                return -ENXIO;

        *rid_out = map->output_base + (rid_in - map->input_base);
        return 0;
}

static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
                                               u32 *id_out, int index)
{
        struct acpi_iort_node *parent;
        struct acpi_iort_id_mapping *map;

        if (!node->mapping_offset || !node->mapping_count ||
                                     index >= node->mapping_count)
                return NULL;

        map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
                           node->mapping_offset + index * sizeof(*map));

        /* Firmware bug! */
        if (!map->output_reference) {
                pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
                       node, node->type);
                return NULL;
        }

        parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
                               map->output_reference);

        if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
                if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT ||
                    node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX ||
                    node->type == ACPI_IORT_NODE_SMMU_V3 ||
                    node->type == ACPI_IORT_NODE_PMCG) {
                        *id_out = map->output_base;
                        return parent;
                }
        }

        return NULL;
}

static int iort_get_id_mapping_index(struct acpi_iort_node *node)
{
        struct acpi_iort_smmu_v3 *smmu;

        switch (node->type) {
        case ACPI_IORT_NODE_SMMU_V3:
                /*
                 * SMMUv3 dev ID mapping index was introduced in revision 1
                 * table, not available in revision 0
                 */
                if (node->revision < 1)
                        return -EINVAL;

                smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
                /*
                 * ID mapping index is only ignored if all interrupts are
                 * GSIV based
                 */
                if (smmu->event_gsiv && smmu->pri_gsiv && smmu->gerr_gsiv
                    && smmu->sync_gsiv)
                        return -EINVAL;

                if (smmu->id_mapping_index >= node->mapping_count) {
                        pr_err(FW_BUG "[node %p type %d] ID mapping index overflows valid mappings\n",
                               node, node->type);
                        return -EINVAL;
                }

                return smmu->id_mapping_index;
        case ACPI_IORT_NODE_PMCG:
                return 0;
        default:
                return -EINVAL;
        }
}

static struct acpi_iort_node *iort_node_map_id(struct acpi_iort_node *node,
                                               u32 id_in, u32 *id_out,
                                               u8 type_mask)
{
        u32 id = id_in;

        /* Parse the ID mapping tree to find specified node type */
        while (node) {
                struct acpi_iort_id_mapping *map;
                int i, index;

                if (IORT_TYPE_MASK(node->type) & type_mask) {
                        if (id_out)
                                *id_out = id;
                        return node;
                }

                if (!node->mapping_offset || !node->mapping_count)
                        goto fail_map;

                map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
                                   node->mapping_offset);

                /* Firmware bug! */
                if (!map->output_reference) {
                        pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
                               node, node->type);
                        goto fail_map;
                }

                /*
                 * Get the special ID mapping index (if any) and skip its
                 * associated ID map to prevent erroneous multi-stage
                 * IORT ID translations.
                 */
                index = iort_get_id_mapping_index(node);

                /* Do the ID translation */
                for (i = 0; i < node->mapping_count; i++, map++) {
                        /* if it is special mapping index, skip it */
                        if (i == index)
                                continue;

                        if (!iort_id_map(map, node->type, id, &id))
                                break;
                }

                if (i == node->mapping_count)
                        goto fail_map;

                node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
                                    map->output_reference);
        }

fail_map:
        /* Map input ID to output ID unchanged on mapping failure */
        if (id_out)
                *id_out = id_in;

        return NULL;
}

static struct acpi_iort_node *iort_node_map_platform_id(
                struct acpi_iort_node *node, u32 *id_out, u8 type_mask,
                int index)
{
        struct acpi_iort_node *parent;
        u32 id;

        /* step 1: retrieve the initial dev id */
        parent = iort_node_get_id(node, &id, index);
        if (!parent)
                return NULL;

        /*
         * optional step 2: map the initial dev id if its parent is not
         * the target type we want, map it again for the use cases such
         * as NC (named component) -> SMMU -> ITS. If the type is matched,
         * return the initial dev id and its parent pointer directly.
         */
        if (!(IORT_TYPE_MASK(parent->type) & type_mask))
                parent = iort_node_map_id(parent, id, id_out, type_mask);
        else
                if (id_out)
                        *id_out = id;

        return parent;
}

static struct acpi_iort_node *iort_find_dev_node(struct device *dev)
{
        struct pci_bus *pbus;

        if (!dev_is_pci(dev)) {
                struct acpi_iort_node *node;
                /*
                 * scan iort_fwnode_list to see if it's an iort platform
                 * device (such as SMMU, PMCG),its iort node already cached
                 * and associated with fwnode when iort platform devices
                 * were initialized.
                 */
                node = iort_get_iort_node(dev->fwnode);
                if (node)
                        return node;

                /*
                 * if not, then it should be a platform device defined in
                 * DSDT/SSDT (with Named Component node in IORT)
                 */
                return iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
                                      iort_match_node_callback, dev);
        }

        /* Find a PCI root bus */
        pbus = to_pci_dev(dev)->bus;
        while (!pci_is_root_bus(pbus))
                pbus = pbus->parent;

        return iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
                              iort_match_node_callback, &pbus->dev);
}

/**
 * iort_msi_map_rid() - Map a MSI requester ID for a device
 * @dev: The device for which the mapping is to be done.
 * @req_id: The device requester ID.
 *
 * Returns: mapped MSI RID on success, input requester ID otherwise
 */
u32 iort_msi_map_rid(struct device *dev, u32 req_id)
{
        struct acpi_iort_node *node;
        u32 dev_id;

        node = iort_find_dev_node(dev);
        if (!node)
                return req_id;

        iort_node_map_id(node, req_id, &dev_id, IORT_MSI_TYPE);
        return dev_id;
}

/**
 * iort_pmsi_get_dev_id() - Get the device id for a device
 * @dev: The device for which the mapping is to be done.
 * @dev_id: The device ID found.
 *
 * Returns: 0 for successful find a dev id, -ENODEV on error
 */
int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
{
        int i, index;
        struct acpi_iort_node *node;

        node = iort_find_dev_node(dev);
        if (!node)
                return -ENODEV;

        index = iort_get_id_mapping_index(node);
        /* if there is a valid index, go get the dev_id directly */
        if (index >= 0) {
                if (iort_node_get_id(node, dev_id, index))
                        return 0;
        } else {
                for (i = 0; i < node->mapping_count; i++) {
                        if (iort_node_map_platform_id(node, dev_id,
                                                      IORT_MSI_TYPE, i))
                                return 0;
                }
        }

        return -ENODEV;
}

static int __maybe_unused iort_find_its_base(u32 its_id, phys_addr_t *base)
{
        struct iort_its_msi_chip *its_msi_chip;
        int ret = -ENODEV;

        spin_lock(&iort_msi_chip_lock);
        list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
                if (its_msi_chip->translation_id == its_id) {
                        *base = its_msi_chip->base_addr;
                        ret = 0;
                        break;
                }
        }
        spin_unlock(&iort_msi_chip_lock);

        return ret;
}

/**
 * iort_dev_find_its_id() - Find the ITS identifier for a device
 * @dev: The device.
 * @req_id: Device's requester ID
 * @idx: Index of the ITS identifier list.
 * @its_id: ITS identifier.
 *
 * Returns: 0 on success, appropriate error value otherwise
 */
static int iort_dev_find_its_id(struct device *dev, u32 req_id,
                                unsigned int idx, int *its_id)
{
        struct acpi_iort_its_group *its;
        struct acpi_iort_node *node;

        node = iort_find_dev_node(dev);
        if (!node)
                return -ENXIO;

        node = iort_node_map_id(node, req_id, NULL, IORT_MSI_TYPE);
        if (!node)
                return -ENXIO;

        /* Move to ITS specific data */
        its = (struct acpi_iort_its_group *)node->node_data;
        if (idx >= its->its_count) {
                dev_err(dev, "requested ITS ID index [%d] overruns ITS entries [%d]\n",
                        idx, its->its_count);
                return -ENXIO;
        }

        *its_id = its->identifiers[idx];
        return 0;
}

/**
 * iort_get_device_domain() - Find MSI domain related to a device
 * @dev: The device.
 * @req_id: Requester ID for the device.
 *
 * Returns: the MSI domain for this device, NULL otherwise
 */
struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id)
{
        struct fwnode_handle *handle;
        int its_id;

        if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
                return NULL;

        handle = iort_find_domain_token(its_id);
        if (!handle)
                return NULL;

        return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
}

static void iort_set_device_domain(struct device *dev,
                                   struct acpi_iort_node *node)
{
        struct acpi_iort_its_group *its;
        struct acpi_iort_node *msi_parent;
        struct acpi_iort_id_mapping *map;
        struct fwnode_handle *iort_fwnode;
        struct irq_domain *domain;
        int index;

        index = iort_get_id_mapping_index(node);
        if (index < 0)
                return;

        map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
                           node->mapping_offset + index * sizeof(*map));

        /* Firmware bug! */
        if (!map->output_reference ||
            !(map->flags & ACPI_IORT_ID_SINGLE_MAPPING)) {
                pr_err(FW_BUG "[node %p type %d] Invalid MSI mapping\n",
                       node, node->type);
                return;
        }

        msi_parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
                                  map->output_reference);

        if (!msi_parent || msi_parent->type != ACPI_IORT_NODE_ITS_GROUP)
                return;

        /* Move to ITS specific data */
        its = (struct acpi_iort_its_group *)msi_parent->node_data;

        iort_fwnode = iort_find_domain_token(its->identifiers[0]);
        if (!iort_fwnode)
                return;

        domain = irq_find_matching_fwnode(iort_fwnode, DOMAIN_BUS_PLATFORM_MSI);
        if (domain)
                dev_set_msi_domain(dev, domain);
}

/**
 * iort_get_platform_device_domain() - Find MSI domain related to a
 * platform device
 * @dev: the dev pointer associated with the platform device
 *
 * Returns: the MSI domain for this device, NULL otherwise
 */
static struct irq_domain *iort_get_platform_device_domain(struct device *dev)
{
        struct acpi_iort_node *node, *msi_parent = NULL;
        struct fwnode_handle *iort_fwnode;
        struct acpi_iort_its_group *its;
        int i;

        /* find its associated iort node */
        node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
                              iort_match_node_callback, dev);
        if (!node)
                return NULL;

        /* then find its msi parent node */
        for (i = 0; i < node->mapping_count; i++) {
                msi_parent = iort_node_map_platform_id(node, NULL,
                                                       IORT_MSI_TYPE, i);
                if (msi_parent)
                        break;
        }

        if (!msi_parent)
                return NULL;

        /* Move to ITS specific data */
        its = (struct acpi_iort_its_group *)msi_parent->node_data;

        iort_fwnode = iort_find_domain_token(its->identifiers[0]);
        if (!iort_fwnode)
                return NULL;

        return irq_find_matching_fwnode(iort_fwnode, DOMAIN_BUS_PLATFORM_MSI);
}

void acpi_configure_pmsi_domain(struct device *dev)
{
        struct irq_domain *msi_domain;

        msi_domain = iort_get_platform_device_domain(dev);
        if (msi_domain)
                dev_set_msi_domain(dev, msi_domain);
}

static int __maybe_unused __get_pci_rid(struct pci_dev *pdev, u16 alias,
                                        void *data)
{
        u32 *rid = data;

        *rid = alias;
        return 0;
}

#ifdef CONFIG_IOMMU_API
static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
{
        struct acpi_iort_node *iommu;
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);

        iommu = iort_get_iort_node(fwspec->iommu_fwnode);

        if (iommu && (iommu->type == ACPI_IORT_NODE_SMMU_V3)) {
                struct acpi_iort_smmu_v3 *smmu;

                smmu = (struct acpi_iort_smmu_v3 *)iommu->node_data;
                if (smmu->model == ACPI_IORT_SMMU_V3_HISILICON_HI161X)
                        return iommu;
        }

        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(const struct iommu_ops *ops,
                                         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()
 * @head: Reserved region list from iommu_get_resv_regions()
 *
 * Returns: Number of msi reserved regions on success (0 if platform
 *          doesn't require the reservation or no associated msi regions),
 *          appropriate error value otherwise. The ITS interrupt translation
 *          spaces (ITS_base + SZ_64K, SZ_64K) associated with the device
 *          are the msi reserved regions.
 */
int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
{
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
        struct acpi_iort_its_group *its;
        struct acpi_iort_node *iommu_node, *its_node = NULL;
        int i, resv = 0;

        iommu_node = iort_get_msi_resv_iommu(dev);
        if (!iommu_node)
                return 0;

        /*
         * Current logic to reserve ITS regions relies on HW topologies
         * where a given PCI or named component maps its IDs to only one
         * ITS group; if a PCI or named component can map its IDs to
         * different ITS groups through IORT mappings this function has
         * to be reworked to ensure we reserve regions for all ITS groups
         * a given PCI or named component may map IDs to.
         */

        for (i = 0; i < fwspec->num_ids; i++) {
                its_node = iort_node_map_id(iommu_node,
                                        fwspec->ids[i],
                                        NULL, IORT_MSI_TYPE);
                if (its_node)
                        break;
        }

        if (!its_node)
                return 0;

        /* Move to ITS specific data */
        its = (struct acpi_iort_its_group *)its_node->node_data;

        for (i = 0; i < its->its_count; i++) {
                phys_addr_t base;

                if (!iort_find_its_base(its->identifiers[i], &base)) {
                        int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
                        struct iommu_resv_region *region;

                        region = iommu_alloc_resv_region(base + SZ_64K, SZ_64K,
                                                         prot, IOMMU_RESV_MSI);
                        if (region) {
                                list_add_tail(&region->list, head);
                                resv++;
                        }
                }
        }

        return (resv == its->its_count) ? resv : -ENODEV;
}

static inline bool iort_iommu_driver_enabled(u8 type)
{
        switch (type) {
        case ACPI_IORT_NODE_SMMU_V3:
                return IS_BUILTIN(CONFIG_ARM_SMMU_V3);
        case ACPI_IORT_NODE_SMMU:
                return IS_BUILTIN(CONFIG_ARM_SMMU);
        default:
                pr_warn("IORT node type %u does not describe an SMMU\n", type);
                return false;
        }
}

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;

        pci_rc = (struct acpi_iort_root_complex *)node->node_data;
        return pci_rc->ats_attribute & ACPI_IORT_ATS_SUPPORTED;
}

static int iort_iommu_xlate(struct device *dev, struct acpi_iort_node *node,
                            u32 streamid)
{
        const struct iommu_ops *ops;
        struct fwnode_handle *iort_fwnode;

        if (!node)
                return -ENODEV;

        iort_fwnode = iort_get_fwnode(node);
        if (!iort_fwnode)
                return -ENODEV;

        /*
         * If the ops look-up fails, this means that either
         * the SMMU drivers have not been probed yet or that
         * the SMMU drivers are not built in the kernel;
         * Depending on whether the SMMU drivers are built-in
         * in the kernel or not, defer the IOMMU configuration
         * or just abort it.
         */
        ops = iommu_ops_from_fwnode(iort_fwnode);
        if (!ops)
                return iort_iommu_driver_enabled(node->type) ?
                       -EPROBE_DEFER : -ENODEV;

        return arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops);
}

struct iort_pci_alias_info {
        struct device *dev;
        struct acpi_iort_node *node;
};

static int iort_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
{
        struct iort_pci_alias_info *info = data;
        struct acpi_iort_node *parent;
        u32 streamid;

        parent = iort_node_map_id(info->node, alias, &streamid,
                                  IORT_IOMMU_TYPE);
        return iort_iommu_xlate(info->dev, parent, streamid);
}

/**
 * iort_iommu_configure - Set-up IOMMU configuration for a device.
 *
 * @dev: device to configure
 *
 * Returns: iommu_ops pointer on configuration success
 *          NULL on configuration failure
 */
const struct iommu_ops *iort_iommu_configure(struct device *dev)
{
        struct acpi_iort_node *node, *parent;
        const struct iommu_ops *ops;
        u32 streamid = 0;
        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 pci_bus *bus = to_pci_dev(dev)->bus;
                struct iort_pci_alias_info info = { .dev = dev };

                node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
                                      iort_match_node_callback, &bus->dev);
                if (!node)
                        return NULL;

                info.node = node;
                err = pci_for_each_dma_alias(to_pci_dev(dev),
                                             iort_pci_iommu_init, &info);

                if (!err && iort_pci_rc_supports_ats(node))
                        dev->iommu_fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
        } else {
                int i = 0;

                node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
                                      iort_match_node_callback, dev);
                if (!node)
                        return NULL;

                do {
                        parent = iort_node_map_platform_id(node, &streamid,
                                                           IORT_IOMMU_TYPE,
                                                           i++);

                        if (parent)
                                err = iort_iommu_xlate(dev, parent, streamid);
                } while (parent && !err);
        }

        /*
         * 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(ops, 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;

}
#else
static inline const struct iommu_ops *iort_fwspec_iommu_ops(struct device *dev)
{ return NULL; }
static inline int iort_add_device_replay(const struct iommu_ops *ops,
                                         struct device *dev)
{ return 0; }
int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
{ return 0; }
const struct iommu_ops *iort_iommu_configure(struct device *dev)
{ return NULL; }
#endif

static int nc_dma_get_range(struct device *dev, u64 *size)
{
        struct acpi_iort_node *node;
        struct acpi_iort_named_component *ncomp;

        node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
                              iort_match_node_callback, dev);
        if (!node)
                return -ENODEV;

        ncomp = (struct acpi_iort_named_component *)node->node_data;

        *size = ncomp->memory_address_limit >= 64 ? U64_MAX :
                        1ULL<<ncomp->memory_address_limit;

        return 0;
}

static int rc_dma_get_range(struct device *dev, u64 *size)
{
        struct acpi_iort_node *node;
        struct acpi_iort_root_complex *rc;
        struct pci_bus *pbus = to_pci_dev(dev)->bus;

        node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
                              iort_match_node_callback, &pbus->dev);
        if (!node || node->revision < 1)
                return -ENODEV;

        rc = (struct acpi_iort_root_complex *)node->node_data;

        *size = rc->memory_address_limit >= 64 ? U64_MAX :
                        1ULL<<rc->memory_address_limit;

        return 0;
}

/**
 * iort_dma_setup() - Set-up device DMA parameters.
 *
 * @dev: device to configure
 * @dma_addr: device DMA address result pointer
 * @size: DMA range size result pointer
 */
void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
{
        u64 mask, dmaaddr = 0, size = 0, offset = 0;
        int ret, msb;

        /*
         * 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;

        if (dev_is_pci(dev)) {
                ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
                if (ret == -ENODEV)
                        ret = rc_dma_get_range(dev, &size);
        } else {
                ret = nc_dma_get_range(dev, &size);
        }

        if (!ret) {
                msb = fls64(dmaaddr + size - 1);
                /*
                 * Round-up to the power-of-two mask or set
                 * the mask to the whole 64-bit address space
                 * in case the DMA region covers the full
                 * memory window.
                 */
                mask = msb == 64 ? U64_MAX : (1ULL << msb) - 1;
                /*
                 * Limit coherent and dma mask based on size
                 * retrieved from firmware.
                 */
                dev->bus_dma_mask = mask;
                dev->coherent_dma_mask = mask;
                *dev->dma_mask = mask;
        }

        *dma_addr = dmaaddr;
        *dma_size = size;

        dev->dma_pfn_offset = PFN_DOWN(offset);
        dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);
}

static void __init acpi_iort_register_irq(int hwirq, const char *name,
                                          int trigger,
                                          struct resource *res)
{
        int irq = acpi_register_gsi(NULL, hwirq, trigger,
                                    ACPI_ACTIVE_HIGH);

        if (irq <= 0) {
                pr_err("could not register gsi hwirq %d name [%s]\n", hwirq,
                                                                      name);
                return;
        }

        res->start = irq;
        res->end = irq;
        res->flags = IORESOURCE_IRQ;
        res->name = name;
}

static int __init arm_smmu_v3_count_resources(struct acpi_iort_node *node)
{
        struct acpi_iort_smmu_v3 *smmu;
        /* Always present mem resource */
        int num_res = 1;

        /* Retrieve SMMUv3 specific data */
        smmu = (struct acpi_iort_smmu_v3 *)node->node_data;

        if (smmu->event_gsiv)
                num_res++;

        if (smmu->pri_gsiv)
                num_res++;

        if (smmu->gerr_gsiv)
                num_res++;

        if (smmu->sync_gsiv)
                num_res++;

        return num_res;
}

static bool arm_smmu_v3_is_combined_irq(struct acpi_iort_smmu_v3 *smmu)
{
        /*
         * Cavium ThunderX2 implementation doesn't not support unique
         * irq line. Use single irq line for all the SMMUv3 interrupts.
         */
        if (smmu->model != ACPI_IORT_SMMU_V3_CAVIUM_CN99XX)
                return false;

        /*
         * ThunderX2 doesn't support MSIs from the SMMU, so we're checking
         * SPI numbers here.
         */
        return smmu->event_gsiv == smmu->pri_gsiv &&
               smmu->event_gsiv == smmu->gerr_gsiv &&
               smmu->event_gsiv == smmu->sync_gsiv;
}

static unsigned long arm_smmu_v3_resource_size(struct acpi_iort_smmu_v3 *smmu)
{
        /*
         * Override the size, for Cavium ThunderX2 implementation
         * which doesn't support the page 1 SMMU register space.
         */
        if (smmu->model == ACPI_IORT_SMMU_V3_CAVIUM_CN99XX)
                return SZ_64K;

        return SZ_128K;
}

static void __init arm_smmu_v3_init_resources(struct resource *res,
                                              struct acpi_iort_node *node)
{
        struct acpi_iort_smmu_v3 *smmu;
        int num_res = 0;

        /* Retrieve SMMUv3 specific data */
        smmu = (struct acpi_iort_smmu_v3 *)node->node_data;

        res[num_res].start = smmu->base_address;
        res[num_res].end = smmu->base_address +
                                arm_smmu_v3_resource_size(smmu) - 1;
        res[num_res].flags = IORESOURCE_MEM;

        num_res++;
        if (arm_smmu_v3_is_combined_irq(smmu)) {
                if (smmu->event_gsiv)
                        acpi_iort_register_irq(smmu->event_gsiv, "combined",
                                               ACPI_EDGE_SENSITIVE,
                                               &res[num_res++]);
        } else {

                if (smmu->event_gsiv)
                        acpi_iort_register_irq(smmu->event_gsiv, "eventq",
                                               ACPI_EDGE_SENSITIVE,
                                               &res[num_res++]);

                if (smmu->pri_gsiv)
                        acpi_iort_register_irq(smmu->pri_gsiv, "priq",
                                               ACPI_EDGE_SENSITIVE,
                                               &res[num_res++]);

                if (smmu->gerr_gsiv)
                        acpi_iort_register_irq(smmu->gerr_gsiv, "gerror",
                                               ACPI_EDGE_SENSITIVE,
                                               &res[num_res++]);

                if (smmu->sync_gsiv)
                        acpi_iort_register_irq(smmu->sync_gsiv, "cmdq-sync",
                                               ACPI_EDGE_SENSITIVE,
                                               &res[num_res++]);
        }
}

static void __init arm_smmu_v3_dma_configure(struct device *dev,
                                             struct acpi_iort_node *node)
{
        struct acpi_iort_smmu_v3 *smmu;
        enum dev_dma_attr attr;

        /* Retrieve SMMUv3 specific data */
        smmu = (struct acpi_iort_smmu_v3 *)node->node_data;

        attr = (smmu->flags & ACPI_IORT_SMMU_V3_COHACC_OVERRIDE) ?
                        DEV_DMA_COHERENT : DEV_DMA_NON_COHERENT;

        /* We expect the dma masks to be equivalent for all SMMUv3 set-ups */
        dev->dma_mask = &dev->coherent_dma_mask;

        /* Configure DMA for the page table walker */
        acpi_dma_configure(dev, attr);
}

#if defined(CONFIG_ACPI_NUMA)
/*
 * set numa proximity domain for smmuv3 device
 */
static int  __init arm_smmu_v3_set_proximity(struct device *dev,
                                              struct acpi_iort_node *node)
{
        struct acpi_iort_smmu_v3 *smmu;

        smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
        if (smmu->flags & ACPI_IORT_SMMU_V3_PXM_VALID) {
                int node = acpi_map_pxm_to_node(smmu->pxm);

                if (node != NUMA_NO_NODE && !node_online(node))
                        return -EINVAL;

                set_dev_node(dev, node);
                pr_info("SMMU-v3[%llx] Mapped to Proximity domain %d\n",
                        smmu->base_address,
                        smmu->pxm);
        }
        return 0;
}
#else
#define arm_smmu_v3_set_proximity NULL
#endif

static int __init arm_smmu_count_resources(struct acpi_iort_node *node)
{
        struct acpi_iort_smmu *smmu;

        /* Retrieve SMMU specific data */
        smmu = (struct acpi_iort_smmu *)node->node_data;

        /*
         * Only consider the global fault interrupt and ignore the
         * configuration access interrupt.
         *
         * MMIO address and global fault interrupt resources are always
         * present so add them to the context interrupt count as a static
         * value.
         */
        return smmu->context_interrupt_count + 2;
}

static void __init arm_smmu_init_resources(struct resource *res,
                                           struct acpi_iort_node *node)
{
        struct acpi_iort_smmu *smmu;
        int i, hw_irq, trigger, num_res = 0;
        u64 *ctx_irq, *glb_irq;

        /* Retrieve SMMU specific data */
        smmu = (struct acpi_iort_smmu *)node->node_data;

        res[num_res].start = smmu->base_address;
        res[num_res].end = smmu->base_address + smmu->span - 1;
        res[num_res].flags = IORESOURCE_MEM;
        num_res++;

        glb_irq = ACPI_ADD_PTR(u64, node, smmu->global_interrupt_offset);
        /* Global IRQs */
        hw_irq = IORT_IRQ_MASK(glb_irq[0]);
        trigger = IORT_IRQ_TRIGGER_MASK(glb_irq[0]);

        acpi_iort_register_irq(hw_irq, "arm-smmu-global", trigger,
                                     &res[num_res++]);

        /* Context IRQs */
        ctx_irq = ACPI_ADD_PTR(u64, node, smmu->context_interrupt_offset);
        for (i = 0; i < smmu->context_interrupt_count; i++) {
                hw_irq = IORT_IRQ_MASK(ctx_irq[i]);
                trigger = IORT_IRQ_TRIGGER_MASK(ctx_irq[i]);

                acpi_iort_register_irq(hw_irq, "arm-smmu-context", trigger,
                                       &res[num_res++]);
        }
}

static void __init arm_smmu_dma_configure(struct device *dev,
                                          struct acpi_iort_node *node)
{
        struct acpi_iort_smmu *smmu;
        enum dev_dma_attr attr;

        /* Retrieve SMMU specific data */
        smmu = (struct acpi_iort_smmu *)node->node_data;

        attr = (smmu->flags & ACPI_IORT_SMMU_COHERENT_WALK) ?
                        DEV_DMA_COHERENT : DEV_DMA_NON_COHERENT;

        /* We expect the dma masks to be equivalent for SMMU set-ups */
        dev->dma_mask = &dev->coherent_dma_mask;

        /* Configure DMA for the page table walker */
        acpi_dma_configure(dev, attr);
}

static int __init arm_smmu_v3_pmcg_count_resources(struct acpi_iort_node *node)
{
        struct acpi_iort_pmcg *pmcg;

        /* Retrieve PMCG specific data */
        pmcg = (struct acpi_iort_pmcg *)node->node_data;

        /*
         * There are always 2 memory resources.
         * If the overflow_gsiv is present then add that for a total of 3.
         */
        return pmcg->overflow_gsiv ? 3 : 2;
}

static void __init arm_smmu_v3_pmcg_init_resources(struct resource *res,
                                                   struct acpi_iort_node *node)
{
        struct acpi_iort_pmcg *pmcg;

        /* Retrieve PMCG specific data */
        pmcg = (struct acpi_iort_pmcg *)node->node_data;

        res[0].start = pmcg->page0_base_address;
        res[0].end = pmcg->page0_base_address + SZ_4K - 1;
        res[0].flags = IORESOURCE_MEM;
        res[1].start = pmcg->page1_base_address;
        res[1].end = pmcg->page1_base_address + SZ_4K - 1;
        res[1].flags = IORESOURCE_MEM;

        if (pmcg->overflow_gsiv)
                acpi_iort_register_irq(pmcg->overflow_gsiv, "overflow",
                                       ACPI_EDGE_SENSITIVE, &res[2]);
}

static struct acpi_platform_list pmcg_plat_info[] __initdata = {
        /* HiSilicon Hip08 Platform */
        {"HISI  ", "HIP08   ", 0, ACPI_SIG_IORT, greater_than_or_equal,
         "Erratum #162001800", IORT_SMMU_V3_PMCG_HISI_HIP08},
        { }
};

static int __init arm_smmu_v3_pmcg_add_platdata(struct platform_device *pdev)
{
        u32 model;
        int idx;

        idx = acpi_match_platform_list(pmcg_plat_info);
        if (idx >= 0)
                model = pmcg_plat_info[idx].data;
        else
                model = IORT_SMMU_V3_PMCG_GENERIC;

        return platform_device_add_data(pdev, &model, sizeof(model));
}

struct iort_dev_config {
        const char *name;
        int (*dev_init)(struct acpi_iort_node *node);
        void (*dev_dma_configure)(struct device *dev,
                                  struct acpi_iort_node *node);
        int (*dev_count_resources)(struct acpi_iort_node *node);
        void (*dev_init_resources)(struct resource *res,
                                     struct acpi_iort_node *node);
        int (*dev_set_proximity)(struct device *dev,
                                    struct acpi_iort_node *node);
        int (*dev_add_platdata)(struct platform_device *pdev);
};

static const struct iort_dev_config iort_arm_smmu_v3_cfg __initconst = {
        .name = "arm-smmu-v3",
        .dev_dma_configure = arm_smmu_v3_dma_configure,
        .dev_count_resources = arm_smmu_v3_count_resources,
        .dev_init_resources = arm_smmu_v3_init_resources,
        .dev_set_proximity = arm_smmu_v3_set_proximity,
};

static const struct iort_dev_config iort_arm_smmu_cfg __initconst = {
        .name = "arm-smmu",
        .dev_dma_configure = arm_smmu_dma_configure,
        .dev_count_resources = arm_smmu_count_resources,
        .dev_init_resources = arm_smmu_init_resources,
};

static const struct iort_dev_config iort_arm_smmu_v3_pmcg_cfg __initconst = {
        .name = "arm-smmu-v3-pmcg",
        .dev_count_resources = arm_smmu_v3_pmcg_count_resources,
        .dev_init_resources = arm_smmu_v3_pmcg_init_resources,
        .dev_add_platdata = arm_smmu_v3_pmcg_add_platdata,
};

static __init const struct iort_dev_config *iort_get_dev_cfg(
                        struct acpi_iort_node *node)
{
        switch (node->type) {
        case ACPI_IORT_NODE_SMMU_V3:
                return &iort_arm_smmu_v3_cfg;
        case ACPI_IORT_NODE_SMMU:
                return &iort_arm_smmu_cfg;
        case ACPI_IORT_NODE_PMCG:
                return &iort_arm_smmu_v3_pmcg_cfg;
        default:
                return NULL;
        }
}

/**
 * iort_add_platform_device() - Allocate a platform device for IORT node
 * @node: Pointer to device ACPI IORT node
 *
 * Returns: 0 on success, <0 failure
 */
static int __init iort_add_platform_device(struct acpi_iort_node *node,
                                           const struct iort_dev_config *ops)
{
        struct fwnode_handle *fwnode;
        struct platform_device *pdev;
        struct resource *r;
        int ret, count;

        pdev = platform_device_alloc(ops->name, PLATFORM_DEVID_AUTO);
        if (!pdev)
                return -ENOMEM;

        if (ops->dev_set_proximity) {
                ret = ops->dev_set_proximity(&pdev->dev, node);
                if (ret)
                        goto dev_put;
        }

        count = ops->dev_count_resources(node);

        r = kcalloc(count, sizeof(*r), GFP_KERNEL);
        if (!r) {
                ret = -ENOMEM;
                goto dev_put;
        }

        ops->dev_init_resources(r, node);

        ret = platform_device_add_resources(pdev, r, count);
        /*
         * Resources are duplicated in platform_device_add_resources,
         * free their allocated memory
         */
        kfree(r);

        if (ret)
                goto dev_put;

        /*
         * Platform devices based on PMCG nodes uses platform_data to
         * pass the hardware model info to the driver. For others, add
         * a copy of IORT node pointer to platform_data to be used to
         * retrieve IORT data information.
         */
        if (ops->dev_add_platdata)
                ret = ops->dev_add_platdata(pdev);
        else
                ret = platform_device_add_data(pdev, &node, sizeof(node));

        if (ret)
                goto dev_put;

        fwnode = iort_get_fwnode(node);

        if (!fwnode) {
                ret = -ENODEV;
                goto dev_put;
        }

        pdev->dev.fwnode = fwnode;

        if (ops->dev_dma_configure)
                ops->dev_dma_configure(&pdev->dev, node);

        iort_set_device_domain(&pdev->dev, node);

        ret = platform_device_add(pdev);
        if (ret)
                goto dma_deconfigure;

        return 0;

dma_deconfigure:
        arch_teardown_dma_ops(&pdev->dev);
dev_put:
        platform_device_put(pdev);

        return ret;
}

#ifdef CONFIG_PCI
static void __init iort_enable_acs(struct acpi_iort_node *iort_node)
{
        static bool acs_enabled __initdata;

        if (acs_enabled)
                return;

        if (iort_node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
                struct acpi_iort_node *parent;
                struct acpi_iort_id_mapping *map;
                int i;

                map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, iort_node,
                                   iort_node->mapping_offset);

                for (i = 0; i < iort_node->mapping_count; i++, map++) {
                        if (!map->output_reference)
                                continue;

                        parent = ACPI_ADD_PTR(struct acpi_iort_node,
                                        iort_table,  map->output_reference);
                        /*
                         * If we detect a RC->SMMU mapping, make sure
                         * we enable ACS on the system.
                         */
                        if ((parent->type == ACPI_IORT_NODE_SMMU) ||
                                (parent->type == ACPI_IORT_NODE_SMMU_V3)) {
                                pci_request_acs();
                                acs_enabled = true;
                                return;
                        }
                }
        }
}
#else
static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { }
#endif

static void __init iort_init_platform_devices(void)
{
        struct acpi_iort_node *iort_node, *iort_end;
        struct acpi_table_iort *iort;
        struct fwnode_handle *fwnode;
        int i, ret;
        const struct iort_dev_config *ops;

        /*
         * iort_table and iort both point to the start of IORT table, but
         * have different struct types
         */
        iort = (struct acpi_table_iort *)iort_table;

        /* Get the first IORT node */
        iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
                                 iort->node_offset);
        iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort,
                                iort_table->length);

        for (i = 0; i < iort->node_count; i++) {
                if (iort_node >= iort_end) {
                        pr_err("iort node pointer overflows, bad table\n");
                        return;
                }

                iort_enable_acs(iort_node);

                ops = iort_get_dev_cfg(iort_node);
                if (ops) {
                        fwnode = acpi_alloc_fwnode_static();
                        if (!fwnode)
                                return;

                        iort_set_fwnode(iort_node, fwnode);

                        ret = iort_add_platform_device(iort_node, ops);
                        if (ret) {
                                iort_delete_fwnode(iort_node);
                                acpi_free_fwnode_static(fwnode);
                                return;
                        }
                }

                iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
                                         iort_node->length);
        }
}

void __init acpi_iort_init(void)
{
        acpi_status status;

        status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table);
        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;
        }

        iort_init_platform_devices();
}