/*
 * Copyright (C) 2007-2010 Advanced Micro Devices, Inc.
 * Author: Joerg Roedel <joerg.roedel@amd.com>
 *         Leo Duran <leo.duran@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/ratelimit.h>
#include <linux/pci.h>
#include <linux/pci-ats.h>
#include <linux/bitmap.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/iommu-helper.h>
#include <linux/iommu.h>
#include <linux/delay.h>
#include <linux/amd-iommu.h>
#include <linux/notifier.h>
#include <linux/export.h>
#include <linux/irq.h>
#include <linux/msi.h>
#include <asm/irq_remapping.h>
#include <asm/io_apic.h>
#include <asm/apic.h>
#include <asm/hw_irq.h>
#include <asm/msidef.h>
#include <asm/proto.h>
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/dma.h>

#include "amd_iommu_proto.h"
#include "amd_iommu_types.h"
#include "irq_remapping.h"
#include "pci.h"

#define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))

#define LOOP_TIMEOUT    100000

/*
 * This bitmap is used to advertise the page sizes our hardware support
 * to the IOMMU core, which will then use this information to split
 * physically contiguous memory regions it is mapping into page sizes
 * that we support.
 *
 * 512GB Pages are not supported due to a hardware bug
 */
#define AMD_IOMMU_PGSIZES       ((~0xFFFUL) & ~(2ULL << 38))

static DEFINE_RWLOCK(amd_iommu_devtable_lock);

/* A list of preallocated protection domains */
static LIST_HEAD(iommu_pd_list);
static DEFINE_SPINLOCK(iommu_pd_list_lock);

/* List of all available dev_data structures */
static LIST_HEAD(dev_data_list);
static DEFINE_SPINLOCK(dev_data_list_lock);

LIST_HEAD(ioapic_map);
LIST_HEAD(hpet_map);

/*
 * Domain for untranslated devices - only allocated
 * if iommu=pt passed on kernel cmd line.
 */
static struct protection_domain *pt_domain;

static struct iommu_ops amd_iommu_ops;

static ATOMIC_NOTIFIER_HEAD(ppr_notifier);
int amd_iommu_max_glx_val = -1;

static struct dma_map_ops amd_iommu_dma_ops;

/*
 * general struct to manage commands send to an IOMMU
 */
struct iommu_cmd {
        u32 data[4];
};

struct kmem_cache *amd_iommu_irq_cache;

static void update_domain(struct protection_domain *domain);
static int __init alloc_passthrough_domain(void);

/****************************************************************************
 *
 * Helper functions
 *
 ****************************************************************************/

static struct iommu_dev_data *alloc_dev_data(u16 devid)
{
        struct iommu_dev_data *dev_data;
        unsigned long flags;

        dev_data = kzalloc(sizeof(*dev_data), GFP_KERNEL);
        if (!dev_data)
                return NULL;

        dev_data->devid = devid;
        atomic_set(&dev_data->bind, 0);

        spin_lock_irqsave(&dev_data_list_lock, flags);
        list_add_tail(&dev_data->dev_data_list, &dev_data_list);
        spin_unlock_irqrestore(&dev_data_list_lock, flags);

        return dev_data;
}

static void free_dev_data(struct iommu_dev_data *dev_data)
{
        unsigned long flags;

        spin_lock_irqsave(&dev_data_list_lock, flags);
        list_del(&dev_data->dev_data_list);
        spin_unlock_irqrestore(&dev_data_list_lock, flags);

        if (dev_data->group)
                iommu_group_put(dev_data->group);

        kfree(dev_data);
}

static struct iommu_dev_data *search_dev_data(u16 devid)
{
        struct iommu_dev_data *dev_data;
        unsigned long flags;

        spin_lock_irqsave(&dev_data_list_lock, flags);
        list_for_each_entry(dev_data, &dev_data_list, dev_data_list) {
                if (dev_data->devid == devid)
                        goto out_unlock;
        }

        dev_data = NULL;

out_unlock:
        spin_unlock_irqrestore(&dev_data_list_lock, flags);

        return dev_data;
}

static struct iommu_dev_data *find_dev_data(u16 devid)
{
        struct iommu_dev_data *dev_data;

        dev_data = search_dev_data(devid);

        if (dev_data == NULL)
                dev_data = alloc_dev_data(devid);

        return dev_data;
}

static inline u16 get_device_id(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);

        return PCI_DEVID(pdev->bus->number, pdev->devfn);
}

static struct iommu_dev_data *get_dev_data(struct device *dev)
{
        return dev->archdata.iommu;
}

static bool pci_iommuv2_capable(struct pci_dev *pdev)
{
        static const int caps[] = {
                PCI_EXT_CAP_ID_ATS,
                PCI_EXT_CAP_ID_PRI,
                PCI_EXT_CAP_ID_PASID,
        };
        int i, pos;

        for (i = 0; i < 3; ++i) {
                pos = pci_find_ext_capability(pdev, caps[i]);
                if (pos == 0)
                        return false;
        }

        return true;
}

static bool pdev_pri_erratum(struct pci_dev *pdev, u32 erratum)
{
        struct iommu_dev_data *dev_data;

        dev_data = get_dev_data(&pdev->dev);

        return dev_data->errata & (1 << erratum) ? true : false;
}

/*
 * In this function the list of preallocated protection domains is traversed to
 * find the domain for a specific device
 */
static struct dma_ops_domain *find_protection_domain(u16 devid)
{
        struct dma_ops_domain *entry, *ret = NULL;
        unsigned long flags;
        u16 alias = amd_iommu_alias_table[devid];

        if (list_empty(&iommu_pd_list))
                return NULL;

        spin_lock_irqsave(&iommu_pd_list_lock, flags);

        list_for_each_entry(entry, &iommu_pd_list, list) {
                if (entry->target_dev == devid ||
                    entry->target_dev == alias) {
                        ret = entry;
                        break;
                }
        }

        spin_unlock_irqrestore(&iommu_pd_list_lock, flags);

        return ret;
}

/*
 * This function checks if the driver got a valid device from the caller to
 * avoid dereferencing invalid pointers.
 */
static bool check_device(struct device *dev)
{
        u16 devid;

        if (!dev || !dev->dma_mask)
                return false;

        /* No device or no PCI device */
        if (dev->bus != &pci_bus_type)
                return false;

        devid = get_device_id(dev);

        /* Out of our scope? */
        if (devid > amd_iommu_last_bdf)
                return false;

        if (amd_iommu_rlookup_table[devid] == NULL)
                return false;

        return true;
}

static struct pci_bus *find_hosted_bus(struct pci_bus *bus)
{
        while (!bus->self) {
                if (!pci_is_root_bus(bus))
                        bus = bus->parent;
                else
                        return ERR_PTR(-ENODEV);
        }

        return bus;
}

#define REQ_ACS_FLAGS   (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)

static struct pci_dev *get_isolation_root(struct pci_dev *pdev)
{
        struct pci_dev *dma_pdev = pdev;

        /* Account for quirked devices */
        swap_pci_ref(&dma_pdev, pci_get_dma_source(dma_pdev));

        /*
         * If it's a multifunction device that does not support our
         * required ACS flags, add to the same group as function 0.
         */
        if (dma_pdev->multifunction &&
            !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))
                swap_pci_ref(&dma_pdev,
                             pci_get_slot(dma_pdev->bus,
                                          PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
                                          0)));

        /*
         * Devices on the root bus go through the iommu.  If that's not us,
         * find the next upstream device and test ACS up to the root bus.
         * Finding the next device may require skipping virtual buses.
         */
        while (!pci_is_root_bus(dma_pdev->bus)) {
                struct pci_bus *bus = find_hosted_bus(dma_pdev->bus);
                if (IS_ERR(bus))
                        break;

                if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))
                        break;

                swap_pci_ref(&dma_pdev, pci_dev_get(bus->self));
        }

        return dma_pdev;
}

static int use_pdev_iommu_group(struct pci_dev *pdev, struct device *dev)
{
        struct iommu_group *group = iommu_group_get(&pdev->dev);
        int ret;

        if (!group) {
                group = iommu_group_alloc();
                if (IS_ERR(group))
                        return PTR_ERR(group);

                WARN_ON(&pdev->dev != dev);
        }

        ret = iommu_group_add_device(group, dev);
        iommu_group_put(group);
        return ret;
}

static int use_dev_data_iommu_group(struct iommu_dev_data *dev_data,
                                    struct device *dev)
{
        if (!dev_data->group) {
                struct iommu_group *group = iommu_group_alloc();
                if (IS_ERR(group))
                        return PTR_ERR(group);

                dev_data->group = group;
        }

        return iommu_group_add_device(dev_data->group, dev);
}

static int init_iommu_group(struct device *dev)
{
        struct iommu_dev_data *dev_data;
        struct iommu_group *group;
        struct pci_dev *dma_pdev;
        int ret;

        group = iommu_group_get(dev);
        if (group) {
                iommu_group_put(group);
                return 0;
        }

        dev_data = find_dev_data(get_device_id(dev));
        if (!dev_data)
                return -ENOMEM;

        if (dev_data->alias_data) {
                u16 alias;
                struct pci_bus *bus;

                if (dev_data->alias_data->group)
                        goto use_group;

                /*
                 * If the alias device exists, it's effectively just a first
                 * level quirk for finding the DMA source.
                 */
                alias = amd_iommu_alias_table[dev_data->devid];
                dma_pdev = pci_get_bus_and_slot(alias >> 8, alias & 0xff);
                if (dma_pdev) {
                        dma_pdev = get_isolation_root(dma_pdev);
                        goto use_pdev;
                }

                /*
                 * If the alias is virtual, try to find a parent device
                 * and test whether the IOMMU group is actualy rooted above
                 * the alias.  Be careful to also test the parent device if
                 * we think the alias is the root of the group.
                 */
                bus = pci_find_bus(0, alias >> 8);
                if (!bus)
                        goto use_group;

                bus = find_hosted_bus(bus);
                if (IS_ERR(bus) || !bus->self)
                        goto use_group;

                dma_pdev = get_isolation_root(pci_dev_get(bus->self));
                if (dma_pdev != bus->self || (dma_pdev->multifunction &&
                    !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)))
                        goto use_pdev;

                pci_dev_put(dma_pdev);
                goto use_group;
        }

        dma_pdev = get_isolation_root(pci_dev_get(to_pci_dev(dev)));
use_pdev:
        ret = use_pdev_iommu_group(dma_pdev, dev);
        pci_dev_put(dma_pdev);
        return ret;
use_group:
        return use_dev_data_iommu_group(dev_data->alias_data, dev);
}

static int iommu_init_device(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct iommu_dev_data *dev_data;
        u16 alias;
        int ret;

        if (dev->archdata.iommu)
                return 0;

        dev_data = find_dev_data(get_device_id(dev));
        if (!dev_data)
                return -ENOMEM;

        alias = amd_iommu_alias_table[dev_data->devid];
        if (alias != dev_data->devid) {
                struct iommu_dev_data *alias_data;

                alias_data = find_dev_data(alias);
                if (alias_data == NULL) {
                        pr_err("AMD-Vi: Warning: Unhandled device %s\n",
                                        dev_name(dev));
                        free_dev_data(dev_data);
                        return -ENOTSUPP;
                }
                dev_data->alias_data = alias_data;
        }

        ret = init_iommu_group(dev);
        if (ret)
                return ret;

        if (pci_iommuv2_capable(pdev)) {
                struct amd_iommu *iommu;

                iommu              = amd_iommu_rlookup_table[dev_data->devid];
                dev_data->iommu_v2 = iommu->is_iommu_v2;
        }

        dev->archdata.iommu = dev_data;

        return 0;
}

static void iommu_ignore_device(struct device *dev)
{
        u16 devid, alias;

        devid = get_device_id(dev);
        alias = amd_iommu_alias_table[devid];

        memset(&amd_iommu_dev_table[devid], 0, sizeof(struct dev_table_entry));
        memset(&amd_iommu_dev_table[alias], 0, sizeof(struct dev_table_entry));

        amd_iommu_rlookup_table[devid] = NULL;
        amd_iommu_rlookup_table[alias] = NULL;
}

static void iommu_uninit_device(struct device *dev)
{
        iommu_group_remove_device(dev);

        /*
         * Nothing to do here - we keep dev_data around for unplugged devices
         * and reuse it when the device is re-plugged - not doing so would
         * introduce a ton of races.
         */
}

void __init amd_iommu_uninit_devices(void)
{
        struct iommu_dev_data *dev_data, *n;
        struct pci_dev *pdev = NULL;

        for_each_pci_dev(pdev) {

                if (!check_device(&pdev->dev))
                        continue;

                iommu_uninit_device(&pdev->dev);
        }

        /* Free all of our dev_data structures */
        list_for_each_entry_safe(dev_data, n, &dev_data_list, dev_data_list)
                free_dev_data(dev_data);
}

int __init amd_iommu_init_devices(void)
{
        struct pci_dev *pdev = NULL;
        int ret = 0;

        for_each_pci_dev(pdev) {

                if (!check_device(&pdev->dev))
                        continue;

                ret = iommu_init_device(&pdev->dev);
                if (ret == -ENOTSUPP)
                        iommu_ignore_device(&pdev->dev);
                else if (ret)
                        goto out_free;
        }

        return 0;

out_free:

        amd_iommu_uninit_devices();

        return ret;
}
#ifdef CONFIG_AMD_IOMMU_STATS

/*
 * Initialization code for statistics collection
 */

DECLARE_STATS_COUNTER(compl_wait);
DECLARE_STATS_COUNTER(cnt_map_single);
DECLARE_STATS_COUNTER(cnt_unmap_single);
DECLARE_STATS_COUNTER(cnt_map_sg);
DECLARE_STATS_COUNTER(cnt_unmap_sg);
DECLARE_STATS_COUNTER(cnt_alloc_coherent);
DECLARE_STATS_COUNTER(cnt_free_coherent);
DECLARE_STATS_COUNTER(cross_page);
DECLARE_STATS_COUNTER(domain_flush_single);
DECLARE_STATS_COUNTER(domain_flush_all);
DECLARE_STATS_COUNTER(alloced_io_mem);
DECLARE_STATS_COUNTER(total_map_requests);
DECLARE_STATS_COUNTER(complete_ppr);
DECLARE_STATS_COUNTER(invalidate_iotlb);
DECLARE_STATS_COUNTER(invalidate_iotlb_all);
DECLARE_STATS_COUNTER(pri_requests);

static struct dentry *stats_dir;
static struct dentry *de_fflush;

static void amd_iommu_stats_add(struct __iommu_counter *cnt)
{
        if (stats_dir == NULL)
                return;

        cnt->dent = debugfs_create_u64(cnt->name, 0444, stats_dir,
                                       &cnt->value);
}

static void amd_iommu_stats_init(void)
{
        stats_dir = debugfs_create_dir("amd-iommu", NULL);
        if (stats_dir == NULL)
                return;

        de_fflush  = debugfs_create_bool("fullflush", 0444, stats_dir,
                                         &amd_iommu_unmap_flush);

        amd_iommu_stats_add(&compl_wait);
        amd_iommu_stats_add(&cnt_map_single);
        amd_iommu_stats_add(&cnt_unmap_single);
        amd_iommu_stats_add(&cnt_map_sg);
        amd_iommu_stats_add(&cnt_unmap_sg);
        amd_iommu_stats_add(&cnt_alloc_coherent);
        amd_iommu_stats_add(&cnt_free_coherent);
        amd_iommu_stats_add(&cross_page);
        amd_iommu_stats_add(&domain_flush_single);
        amd_iommu_stats_add(&domain_flush_all);
        amd_iommu_stats_add(&alloced_io_mem);
        amd_iommu_stats_add(&total_map_requests);
        amd_iommu_stats_add(&complete_ppr);
        amd_iommu_stats_add(&invalidate_iotlb);
        amd_iommu_stats_add(&invalidate_iotlb_all);
        amd_iommu_stats_add(&pri_requests);
}

#endif

/****************************************************************************
 *
 * Interrupt handling functions
 *
 ****************************************************************************/

static void dump_dte_entry(u16 devid)
{
        int i;

        for (i = 0; i < 4; ++i)
                pr_err("AMD-Vi: DTE[%d]: %016llx\n", i,
                        amd_iommu_dev_table[devid].data[i]);
}

static void dump_command(unsigned long phys_addr)
{
        struct iommu_cmd *cmd = phys_to_virt(phys_addr);
        int i;

        for (i = 0; i < 4; ++i)
                pr_err("AMD-Vi: CMD[%d]: %08x\n", i, cmd->data[i]);
}

static void iommu_print_event(struct amd_iommu *iommu, void *__evt)
{
        int type, devid, domid, flags;
        volatile u32 *event = __evt;
        int count = 0;
        u64 address;

retry:
        type    = (event[1] >> EVENT_TYPE_SHIFT)  & EVENT_TYPE_MASK;
        devid   = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK;
        domid   = (event[1] >> EVENT_DOMID_SHIFT) & EVENT_DOMID_MASK;
        flags   = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK;
        address = (u64)(((u64)event[3]) << 32) | event[2];

        if (type == 0) {
                /* Did we hit the erratum? */
                if (++count == LOOP_TIMEOUT) {
                        pr_err("AMD-Vi: No event written to event log\n");
                        return;
                }
                udelay(1);
                goto retry;
        }

        printk(KERN_ERR "AMD-Vi: Event logged [");

        switch (type) {
        case EVENT_TYPE_ILL_DEV:
                printk("ILLEGAL_DEV_TABLE_ENTRY device=%02x:%02x.%x "
                       "address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address, flags);
                dump_dte_entry(devid);
                break;
        case EVENT_TYPE_IO_FAULT:
                printk("IO_PAGE_FAULT device=%02x:%02x.%x "
                       "domain=0x%04x address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       domid, address, flags);
                break;
        case EVENT_TYPE_DEV_TAB_ERR:
                printk("DEV_TAB_HARDWARE_ERROR device=%02x:%02x.%x "
                       "address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address, flags);
                break;
        case EVENT_TYPE_PAGE_TAB_ERR:
                printk("PAGE_TAB_HARDWARE_ERROR device=%02x:%02x.%x "
                       "domain=0x%04x address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       domid, address, flags);
                break;
        case EVENT_TYPE_ILL_CMD:
                printk("ILLEGAL_COMMAND_ERROR address=0x%016llx]\n", address);
                dump_command(address);
                break;
        case EVENT_TYPE_CMD_HARD_ERR:
                printk("COMMAND_HARDWARE_ERROR address=0x%016llx "
                       "flags=0x%04x]\n", address, flags);
                break;
        case EVENT_TYPE_IOTLB_INV_TO:
                printk("IOTLB_INV_TIMEOUT device=%02x:%02x.%x "
                       "address=0x%016llx]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address);
                break;
        case EVENT_TYPE_INV_DEV_REQ:
                printk("INVALID_DEVICE_REQUEST device=%02x:%02x.%x "
                       "address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address, flags);
                break;
        default:
                printk(KERN_ERR "UNKNOWN type=0x%02x]\n", type);
        }

        memset(__evt, 0, 4 * sizeof(u32));
}

static void iommu_poll_events(struct amd_iommu *iommu)
{
        u32 head, tail;

        head = readl(iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
        tail = readl(iommu->mmio_base + MMIO_EVT_TAIL_OFFSET);

        while (head != tail) {
                iommu_print_event(iommu, iommu->evt_buf + head);
                head = (head + EVENT_ENTRY_SIZE) % iommu->evt_buf_size;
        }

        writel(head, iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
}

static void iommu_handle_ppr_entry(struct amd_iommu *iommu, u64 *raw)
{
        struct amd_iommu_fault fault;

        INC_STATS_COUNTER(pri_requests);

        if (PPR_REQ_TYPE(raw[0]) != PPR_REQ_FAULT) {
                pr_err_ratelimited("AMD-Vi: Unknown PPR request received\n");
                return;
        }

        fault.address   = raw[1];
        fault.pasid     = PPR_PASID(raw[0]);
        fault.device_id = PPR_DEVID(raw[0]);
        fault.tag       = PPR_TAG(raw[0]);
        fault.flags     = PPR_FLAGS(raw[0]);

        atomic_notifier_call_chain(&ppr_notifier, 0, &fault);
}

static void iommu_poll_ppr_log(struct amd_iommu *iommu)
{
        u32 head, tail;

        if (iommu->ppr_log == NULL)
                return;

        head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
        tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);

        while (head != tail) {
                volatile u64 *raw;
                u64 entry[2];
                int i;

                raw = (u64 *)(iommu->ppr_log + head);

                /*
                 * Hardware bug: Interrupt may arrive before the entry is
                 * written to memory. If this happens we need to wait for the
                 * entry to arrive.
                 */
                for (i = 0; i < LOOP_TIMEOUT; ++i) {
                        if (PPR_REQ_TYPE(raw[0]) != 0)
                                break;
                        udelay(1);
                }

                /* Avoid memcpy function-call overhead */
                entry[0] = raw[0];
                entry[1] = raw[1];

                /*
                 * To detect the hardware bug we need to clear the entry
                 * back to zero.
                 */
                raw[0] = raw[1] = 0UL;

                /* Update head pointer of hardware ring-buffer */
                head = (head + PPR_ENTRY_SIZE) % PPR_LOG_SIZE;
                writel(head, iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);

                /* Handle PPR entry */
                iommu_handle_ppr_entry(iommu, entry);

                /* Refresh ring-buffer information */
                head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
                tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);
        }
}

irqreturn_t amd_iommu_int_thread(int irq, void *data)
{
        struct amd_iommu *iommu = (struct amd_iommu *) data;
        u32 status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);

        while (status & (MMIO_STATUS_EVT_INT_MASK | MMIO_STATUS_PPR_INT_MASK)) {
                /* Enable EVT and PPR interrupts again */
                writel((MMIO_STATUS_EVT_INT_MASK | MMIO_STATUS_PPR_INT_MASK),
                        iommu->mmio_base + MMIO_STATUS_OFFSET);

                if (status & MMIO_STATUS_EVT_INT_MASK) {
                        pr_devel("AMD-Vi: Processing IOMMU Event Log\n");
                        iommu_poll_events(iommu);
                }

                if (status & MMIO_STATUS_PPR_INT_MASK) {
                        pr_devel("AMD-Vi: Processing IOMMU PPR Log\n");
                        iommu_poll_ppr_log(iommu);
                }

                /*
                 * Hardware bug: ERBT1312
                 * When re-enabling interrupt (by writing 1
                 * to clear the bit), the hardware might also try to set
                 * the interrupt bit in the event status register.
                 * In this scenario, the bit will be set, and disable
                 * subsequent interrupts.
                 *
                 * Workaround: The IOMMU driver should read back the
                 * status register and check if the interrupt bits are cleared.
                 * If not, driver will need to go through the interrupt handler
                 * again and re-clear the bits
                 */
                status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
        }
        return IRQ_HANDLED;
}

irqreturn_t amd_iommu_int_handler(int irq, void *data)
{
        return IRQ_WAKE_THREAD;
}

/****************************************************************************
 *
 * IOMMU command queuing functions
 *
 ****************************************************************************/

static int wait_on_sem(volatile u64 *sem)
{
        int i = 0;

        while (*sem == 0 && i < LOOP_TIMEOUT) {
                udelay(1);
                i += 1;
        }

        if (i == LOOP_TIMEOUT) {
                pr_alert("AMD-Vi: Completion-Wait loop timed out\n");
                return -EIO;
        }

        return 0;
}

static void copy_cmd_to_buffer(struct amd_iommu *iommu,
                               struct iommu_cmd *cmd,
                               u32 tail)
{
        u8 *target;

        target = iommu->cmd_buf + tail;
        tail   = (tail + sizeof(*cmd)) % iommu->cmd_buf_size;

        /* Copy command to buffer */
        memcpy(target, cmd, sizeof(*cmd));

        /* Tell the IOMMU about it */
        writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
}

static void build_completion_wait(struct iommu_cmd *cmd, u64 address)
{
        WARN_ON(address & 0x7ULL);

        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0] = lower_32_bits(__pa(address)) | CMD_COMPL_WAIT_STORE_MASK;
        cmd->data[1] = upper_32_bits(__pa(address));
        cmd->data[2] = 1;
        CMD_SET_TYPE(cmd, CMD_COMPL_WAIT);
}

static void build_inv_dte(struct iommu_cmd *cmd, u16 devid)
{
        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0] = devid;
        CMD_SET_TYPE(cmd, CMD_INV_DEV_ENTRY);
}

static void build_inv_iommu_pages(struct iommu_cmd *cmd, u64 address,
                                  size_t size, u16 domid, int pde)
{
        u64 pages;
        int s;

        pages = iommu_num_pages(address, size, PAGE_SIZE);
        s     = 0;

        if (pages > 1) {
                /*
                 * If we have to flush more than one page, flush all
                 * TLB entries for this domain
                 */
                address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
                s = 1;
        }

        address &= PAGE_MASK;

        memset(cmd, 0, sizeof(*cmd));
        cmd->data[1] |= domid;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[3]  = upper_32_bits(address);
        CMD_SET_TYPE(cmd, CMD_INV_IOMMU_PAGES);
        if (s) /* size bit - we flush more than one 4kb page */
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
        if (pde) /* PDE bit - we want to flush everything, not only the PTEs */
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK;
}

static void build_inv_iotlb_pages(struct iommu_cmd *cmd, u16 devid, int qdep,
                                  u64 address, size_t size)
{
        u64 pages;
        int s;

        pages = iommu_num_pages(address, size, PAGE_SIZE);
        s     = 0;

        if (pages > 1) {
                /*
                 * If we have to flush more than one page, flush all
                 * TLB entries for this domain
                 */
                address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
                s = 1;
        }

        address &= PAGE_MASK;

        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0]  = devid;
        cmd->data[0] |= (qdep & 0xff) << 24;
        cmd->data[1]  = devid;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[3]  = upper_32_bits(address);
        CMD_SET_TYPE(cmd, CMD_INV_IOTLB_PAGES);
        if (s)
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
}

static void build_inv_iommu_pasid(struct iommu_cmd *cmd, u16 domid, int pasid,
                                  u64 address, bool size)
{
        memset(cmd, 0, sizeof(*cmd));

        address &= ~(0xfffULL);

        cmd->data[0]  = pasid & PASID_MASK;
        cmd->data[1]  = domid;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[3]  = upper_32_bits(address);
        cmd->data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK;
        cmd->data[2] |= CMD_INV_IOMMU_PAGES_GN_MASK;
        if (size)
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
        CMD_SET_TYPE(cmd, CMD_INV_IOMMU_PAGES);
}

static void build_inv_iotlb_pasid(struct iommu_cmd *cmd, u16 devid, int pasid,
                                  int qdep, u64 address, bool size)
{
        memset(cmd, 0, sizeof(*cmd));

        address &= ~(0xfffULL);

        cmd->data[0]  = devid;
        cmd->data[0] |= (pasid & 0xff) << 16;
        cmd->data[0] |= (qdep  & 0xff) << 24;
        cmd->data[1]  = devid;
        cmd->data[1] |= ((pasid >> 8) & 0xfff) << 16;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[2] |= CMD_INV_IOMMU_PAGES_GN_MASK;
        cmd->data[3]  = upper_32_bits(address);
        if (size)
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
        CMD_SET_TYPE(cmd, CMD_INV_IOTLB_PAGES);
}

static void build_complete_ppr(struct iommu_cmd *cmd, u16 devid, int pasid,
                               int status, int tag, bool gn)
{
        memset(cmd, 0, sizeof(*cmd));

        cmd->data[0]  = devid;
        if (gn) {
                cmd->data[1]  = pasid & PASID_MASK;
                cmd->data[2]  = CMD_INV_IOMMU_PAGES_GN_MASK;
        }
        cmd->data[3]  = tag & 0x1ff;
        cmd->data[3] |= (status & PPR_STATUS_MASK) << PPR_STATUS_SHIFT;

        CMD_SET_TYPE(cmd, CMD_COMPLETE_PPR);
}

static void build_inv_all(struct iommu_cmd *cmd)
{
        memset(cmd, 0, sizeof(*cmd));

        CMD_SET_TYPE(cmd, CMD_INV_ALL);
}

static void build_inv_irt(struct iommu_cmd *cmd, u16 devid)
{
        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0] = devid;
        CMD_SET_TYPE(cmd, CMD_INV_IRT);
}

/*
 * Writes the command to the IOMMUs command buffer and informs the
 * hardware about the new command.
 */
static int iommu_queue_command_sync(struct amd_iommu *iommu,
                                    struct iommu_cmd *cmd,
                                    bool sync)
{
        u32 left, tail, head, next_tail;
        unsigned long flags;

        WARN_ON(iommu->cmd_buf_size & CMD_BUFFER_UNINITIALIZED);

again:
        spin_lock_irqsave(&iommu->lock, flags);

        head      = readl(iommu->mmio_base + MMIO_CMD_HEAD_OFFSET);
        tail      = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
        next_tail = (tail + sizeof(*cmd)) % iommu->cmd_buf_size;
        left      = (head - next_tail) % iommu->cmd_buf_size;

        if (left <= 2) {
                struct iommu_cmd sync_cmd;
                volatile u64 sem = 0;
                int ret;

                build_completion_wait(&sync_cmd, (u64)&sem);
                copy_cmd_to_buffer(iommu, &sync_cmd, tail);

                spin_unlock_irqrestore(&iommu->lock, flags);

                if ((ret = wait_on_sem(&sem)) != 0)
                        return ret;

                goto again;
        }

        copy_cmd_to_buffer(iommu, cmd, tail);

        /* We need to sync now to make sure all commands are processed */
        iommu->need_sync = sync;

        spin_unlock_irqrestore(&iommu->lock, flags);

        return 0;
}

static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
{
        return iommu_queue_command_sync(iommu, cmd, true);
}

/*
 * This function queues a completion wait command into the command
 * buffer of an IOMMU
 */
static int iommu_completion_wait(struct amd_iommu *iommu)
{
        struct iommu_cmd cmd;
        volatile u64 sem = 0;
        int ret;

        if (!iommu->need_sync)
                return 0;

        build_completion_wait(&cmd, (u64)&sem);

        ret = iommu_queue_command_sync(iommu, &cmd, false);
        if (ret)
                return ret;

        return wait_on_sem(&sem);
}

static int iommu_flush_dte(struct amd_iommu *iommu, u16 devid)
{
        struct iommu_cmd cmd;

        build_inv_dte(&cmd, devid);

        return iommu_queue_command(iommu, &cmd);
}

static void iommu_flush_dte_all(struct amd_iommu *iommu)
{
        u32 devid;

        for (devid = 0; devid <= 0xffff; ++devid)
                iommu_flush_dte(iommu, devid);

        iommu_completion_wait(iommu);
}

/*
 * This function uses heavy locking and may disable irqs for some time. But
 * this is no issue because it is only called during resume.
 */
static void iommu_flush_tlb_all(struct amd_iommu *iommu)
{
        u32 dom_id;

        for (dom_id = 0; dom_id <= 0xffff; ++dom_id) {
                struct iommu_cmd cmd;
                build_inv_iommu_pages(&cmd, 0, CMD_INV_IOMMU_ALL_PAGES_ADDRESS,
                                      dom_id, 1);
                iommu_queue_command(iommu, &cmd);
        }

        iommu_completion_wait(iommu);
}

static void iommu_flush_all(struct amd_iommu *iommu)
{
        struct iommu_cmd cmd;

        build_inv_all(&cmd);

        iommu_queue_command(iommu, &cmd);
        iommu_completion_wait(iommu);
}

static void iommu_flush_irt(struct amd_iommu *iommu, u16 devid)
{
        struct iommu_cmd cmd;

        build_inv_irt(&cmd, devid);

        iommu_queue_command(iommu, &cmd);
}

static void iommu_flush_irt_all(struct amd_iommu *iommu)
{
        u32 devid;

        for (devid = 0; devid <= MAX_DEV_TABLE_ENTRIES; devid++)
                iommu_flush_irt(iommu, devid);

        iommu_completion_wait(iommu);
}

void iommu_flush_all_caches(struct amd_iommu *iommu)
{
        if (iommu_feature(iommu, FEATURE_IA)) {
                iommu_flush_all(iommu);
        } else {
                iommu_flush_dte_all(iommu);
                iommu_flush_irt_all(iommu);
                iommu_flush_tlb_all(iommu);
        }
}

/*
 * Command send function for flushing on-device TLB
 */
static int device_flush_iotlb(struct iommu_dev_data *dev_data,
                              u64 address, size_t size)
{
        struct amd_iommu *iommu;
        struct iommu_cmd cmd;
        int qdep;

        qdep     = dev_data->ats.qdep;
        iommu    = amd_iommu_rlookup_table[dev_data->devid];

        build_inv_iotlb_pages(&cmd, dev_data->devid, qdep, address, size);

        return iommu_queue_command(iommu, &cmd);
}

/*
 * Command send function for invalidating a device table entry
 */
static int device_flush_dte(struct iommu_dev_data *dev_data)
{
        struct amd_iommu *iommu;
        int ret;

        iommu = amd_iommu_rlookup_table[dev_data->devid];

        ret = iommu_flush_dte(iommu, dev_data->devid);
        if (ret)
                return ret;

        if (dev_data->ats.enabled)
                ret = device_flush_iotlb(dev_data, 0, ~0UL);

        return ret;
}

/*
 * TLB invalidation function which is called from the mapping functions.
 * It invalidates a single PTE if the range to flush is within a single
 * page. Otherwise it flushes the whole TLB of the IOMMU.
 */
static void __domain_flush_pages(struct protection_domain *domain,
                                 u64 address, size_t size, int pde)
{
        struct iommu_dev_data *dev_data;
        struct iommu_cmd cmd;
        int ret = 0, i;

        build_inv_iommu_pages(&cmd, address, size, domain->id, pde);

        for (i = 0; i < amd_iommus_present; ++i) {
                if (!domain->dev_iommu[i])
                        continue;

                /*
                 * Devices of this domain are behind this IOMMU
                 * We need a TLB flush
                 */
                ret |= iommu_queue_command(amd_iommus[i], &cmd);
        }

        list_for_each_entry(dev_data, &domain->dev_list, list) {

                if (!dev_data->ats.enabled)
                        continue;

                ret |= device_flush_iotlb(dev_data, address, size);
        }

        WARN_ON(ret);
}

static void domain_flush_pages(struct protection_domain *domain,
                               u64 address, size_t size)
{
        __domain_flush_pages(domain, address, size, 0);
}

/* Flush the whole IO/TLB for a given protection domain */
static void domain_flush_tlb(struct protection_domain *domain)
{
        __domain_flush_pages(domain, 0, CMD_INV_IOMMU_ALL_PAGES_ADDRESS, 0);
}

/* Flush the whole IO/TLB for a given protection domain - including PDE */
static void domain_flush_tlb_pde(struct protection_domain *domain)
{
        __domain_flush_pages(domain, 0, CMD_INV_IOMMU_ALL_PAGES_ADDRESS, 1);
}

static void domain_flush_complete(struct protection_domain *domain)
{
        int i;

        for (i = 0; i < amd_iommus_present; ++i) {
                if (!domain->dev_iommu[i])
                        continue;

                /*
                 * Devices of this domain are behind this IOMMU
                 * We need to wait for completion of all commands.
                 */
                iommu_completion_wait(amd_iommus[i]);
        }
}


/*
 * This function flushes the DTEs for all devices in domain
 */
static void domain_flush_devices(struct protection_domain *domain)
{
        struct iommu_dev_data *dev_data;

        list_for_each_entry(dev_data, &domain->dev_list, list)
                device_flush_dte(dev_data);
}

/****************************************************************************
 *
 * The functions below are used the create the page table mappings for
 * unity mapped regions.
 *
 ****************************************************************************/

/*
 * This function is used to add another level to an IO page table. Adding
 * another level increases the size of the address space by 9 bits to a size up
 * to 64 bits.
 */
static bool increase_address_space(struct protection_domain *domain,
                                   gfp_t gfp)
{
        u64 *pte;

        if (domain->mode == PAGE_MODE_6_LEVEL)
                /* address space already 64 bit large */
                return false;

        pte = (void *)get_zeroed_page(gfp);
        if (!pte)
                return false;

        *pte             = PM_LEVEL_PDE(domain->mode,
                                        virt_to_phys(domain->pt_root));
        domain->pt_root  = pte;
        domain->mode    += 1;
        domain->updated  = true;

        return true;
}

static u64 *alloc_pte(struct protection_domain *domain,
                      unsigned long address,
                      unsigned long page_size,
                      u64 **pte_page,
                      gfp_t gfp)
{
        int level, end_lvl;
        u64 *pte, *page;

        BUG_ON(!is_power_of_2(page_size));

        while (address > PM_LEVEL_SIZE(domain->mode))
                increase_address_space(domain, gfp);

        level   = domain->mode - 1;
        pte     = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
        address = PAGE_SIZE_ALIGN(address, page_size);
        end_lvl = PAGE_SIZE_LEVEL(page_size);

        while (level > end_lvl) {
                if (!IOMMU_PTE_PRESENT(*pte)) {
                        page = (u64 *)get_zeroed_page(gfp);
                        if (!page)
                                return NULL;
                        *pte = PM_LEVEL_PDE(level, virt_to_phys(page));
                }

                /* No level skipping support yet */
                if (PM_PTE_LEVEL(*pte) != level)
                        return NULL;

                level -= 1;

                pte = IOMMU_PTE_PAGE(*pte);

                if (pte_page && level == end_lvl)
                        *pte_page = pte;

                pte = &pte[PM_LEVEL_INDEX(level, address)];
        }

        return pte;
}

/*
 * This function checks if there is a PTE for a given dma address. If
 * there is one, it returns the pointer to it.
 */
static u64 *fetch_pte(struct protection_domain *domain, unsigned long address)
{
        int level;
        u64 *pte;

        if (address > PM_LEVEL_SIZE(domain->mode))
                return NULL;

        level   =  domain->mode - 1;
        pte     = &domain->pt_root[PM_LEVEL_INDEX(level, address)];

        while (level > 0) {

                /* Not Present */
                if (!IOMMU_PTE_PRESENT(*pte))
                        return NULL;

                /* Large PTE */
                if (PM_PTE_LEVEL(*pte) == 0x07) {
                        unsigned long pte_mask, __pte;

                        /*
                         * If we have a series of large PTEs, make
                         * sure to return a pointer to the first one.
                         */
                        pte_mask = PTE_PAGE_SIZE(*pte);
                        pte_mask = ~((PAGE_SIZE_PTE_COUNT(pte_mask) << 3) - 1);
                        __pte    = ((unsigned long)pte) & pte_mask;

                        return (u64 *)__pte;
                }

                /* No level skipping support yet */
                if (PM_PTE_LEVEL(*pte) != level)
                        return NULL;

                level -= 1;

                /* Walk to the next level */
                pte = IOMMU_PTE_PAGE(*pte);
                pte = &pte[PM_LEVEL_INDEX(level, address)];
        }

        return pte;
}

/*
 * Generic mapping functions. It maps a physical address into a DMA
 * address space. It allocates the page table pages if necessary.
 * In the future it can be extended to a generic mapping function
 * supporting all features of AMD IOMMU page tables like level skipping
 * and full 64 bit address spaces.
 */
static int iommu_map_page(struct protection_domain *dom,
                          unsigned long bus_addr,
                          unsigned long phys_addr,
                          int prot,
                          unsigned long page_size)
{
        u64 __pte, *pte;
        int i, count;

        if (!(prot & IOMMU_PROT_MASK))
                return -EINVAL;

        bus_addr  = PAGE_ALIGN(bus_addr);
        phys_addr = PAGE_ALIGN(phys_addr);
        count     = PAGE_SIZE_PTE_COUNT(page_size);
        pte       = alloc_pte(dom, bus_addr, page_size, NULL, GFP_KERNEL);

        for (i = 0; i < count; ++i)
                if (IOMMU_PTE_PRESENT(pte[i]))
                        return -EBUSY;

        if (page_size > PAGE_SIZE) {
                __pte = PAGE_SIZE_PTE(phys_addr, page_size);
                __pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_P | IOMMU_PTE_FC;
        } else
                __pte = phys_addr | IOMMU_PTE_P | IOMMU_PTE_FC;

        if (prot & IOMMU_PROT_IR)
                __pte |= IOMMU_PTE_IR;
        if (prot & IOMMU_PROT_IW)
                __pte |= IOMMU_PTE_IW;

        for (i = 0; i < count; ++i)
                pte[i] = __pte;

        update_domain(dom);

        return 0;
}

static unsigned long iommu_unmap_page(struct protection_domain *dom,
                                      unsigned long bus_addr,
                                      unsigned long page_size)
{
        unsigned long long unmap_size, unmapped;
        u64 *pte;

        BUG_ON(!is_power_of_2(page_size));

        unmapped = 0;

        while (unmapped < page_size) {

                pte = fetch_pte(dom, bus_addr);

                if (!pte) {
                        /*
                         * No PTE for this address
                         * move forward in 4kb steps
                         */
                        unmap_size = PAGE_SIZE;
                } else if (PM_PTE_LEVEL(*pte) == 0) {
                        /* 4kb PTE found for this address */
                        unmap_size = PAGE_SIZE;
                        *pte       = 0ULL;
                } else {
                        int count, i;

                        /* Large PTE found which maps this address */
                        unmap_size = PTE_PAGE_SIZE(*pte);
                        count      = PAGE_SIZE_PTE_COUNT(unmap_size);
                        for (i = 0; i < count; i++)
                                pte[i] = 0ULL;
                }

                bus_addr  = (bus_addr & ~(unmap_size - 1)) + unmap_size;
                unmapped += unmap_size;
        }

        BUG_ON(!is_power_of_2(unmapped));

        return unmapped;
}

/*
 * This function checks if a specific unity mapping entry is needed for
 * this specific IOMMU.
 */
static int iommu_for_unity_map(struct amd_iommu *iommu,
                               struct unity_map_entry *entry)
{
        u16 bdf, i;

        for (i = entry->devid_start; i <= entry->devid_end; ++i) {
                bdf = amd_iommu_alias_table[i];
                if (amd_iommu_rlookup_table[bdf] == iommu)
                        return 1;
        }

        return 0;
}

/*
 * This function actually applies the mapping to the page table of the
 * dma_ops domain.
 */
static int dma_ops_unity_map(struct dma_ops_domain *dma_dom,
                             struct unity_map_entry *e)
{
        u64 addr;
        int ret;

        for (addr = e->address_start; addr < e->address_end;
             addr += PAGE_SIZE) {
                ret = iommu_map_page(&dma_dom->domain, addr, addr, e->prot,
                                     PAGE_SIZE);
                if (ret)
                        return ret;
                /*
                 * if unity mapping is in aperture range mark the page
                 * as allocated in the aperture
                 */
                if (addr < dma_dom->aperture_size)
                        __set_bit(addr >> PAGE_SHIFT,
                                  dma_dom->aperture[0]->bitmap);
        }

        return 0;
}

/*
 * Init the unity mappings for a specific IOMMU in the system
 *
 * Basically iterates over all unity mapping entries and applies them to
 * the default domain DMA of that IOMMU if necessary.
 */
static int iommu_init_unity_mappings(struct amd_iommu *iommu)
{
        struct unity_map_entry *entry;
        int ret;

        list_for_each_entry(entry, &amd_iommu_unity_map, list) {
                if (!iommu_for_unity_map(iommu, entry))
                        continue;
                ret = dma_ops_unity_map(iommu->default_dom, entry);
                if (ret)
                        return ret;
        }

        return 0;
}

/*
 * Inits the unity mappings required for a specific device
 */
static int init_unity_mappings_for_device(struct dma_ops_domain *dma_dom,
                                          u16 devid)
{
        struct unity_map_entry *e;
        int ret;

        list_for_each_entry(e, &amd_iommu_unity_map, list) {
                if (!(devid >= e->devid_start && devid <= e->devid_end))
                        continue;
                ret = dma_ops_unity_map(dma_dom, e);
                if (ret)
                        return ret;
        }

        return 0;
}

/****************************************************************************
 *
 * The next functions belong to the address allocator for the dma_ops
 * interface functions. They work like the allocators in the other IOMMU
 * drivers. Its basically a bitmap which marks the allocated pages in
 * the aperture. Maybe it could be enhanced in the future to a more
 * efficient allocator.
 *
 ****************************************************************************/

/*
 * The address allocator core functions.
 *
 * called with domain->lock held
 */

/*
 * Used to reserve address ranges in the aperture (e.g. for exclusion
 * ranges.
 */
static void dma_ops_reserve_addresses(struct dma_ops_domain *dom,
                                      unsigned long start_page,
                                      unsigned int pages)
{
        unsigned int i, last_page = dom->aperture_size >> PAGE_SHIFT;

        if (start_page + pages > last_page)
                pages = last_page - start_page;

        for (i = start_page; i < start_page + pages; ++i) {
                int index = i / APERTURE_RANGE_PAGES;
                int page  = i % APERTURE_RANGE_PAGES;
                __set_bit(page, dom->aperture[index]->bitmap);
        }
}

/*
 * This function is used to add a new aperture range to an existing
 * aperture in case of dma_ops domain allocation or address allocation
 * failure.
 */
static int alloc_new_range(struct dma_ops_domain *dma_dom,
                           bool populate, gfp_t gfp)
{
        int index = dma_dom->aperture_size >> APERTURE_RANGE_SHIFT;
        struct amd_iommu *iommu;
        unsigned long i, old_size;

#ifdef CONFIG_IOMMU_STRESS
        populate = false;
#endif

        if (index >= APERTURE_MAX_RANGES)
                return -ENOMEM;

        dma_dom->aperture[index] = kzalloc(sizeof(struct aperture_range), gfp);
        if (!dma_dom->aperture[index])
                return -ENOMEM;

        dma_dom->aperture[index]->bitmap = (void *)get_zeroed_page(gfp);
        if (!dma_dom->aperture[index]->bitmap)
                goto out_free;

        dma_dom->aperture[index]->offset = dma_dom->aperture_size;

        if (populate) {
                unsigned long address = dma_dom->aperture_size;
                int i, num_ptes = APERTURE_RANGE_PAGES / 512;
                u64 *pte, *pte_page;

                for (i = 0; i < num_ptes; ++i) {
                        pte = alloc_pte(&dma_dom->domain, address, PAGE_SIZE,
                                        &pte_page, gfp);
                        if (!pte)
                                goto out_free;

                        dma_dom->aperture[index]->pte_pages[i] = pte_page;

                        address += APERTURE_RANGE_SIZE / 64;
                }
        }

        old_size                = dma_dom->aperture_size;
        dma_dom->aperture_size += APERTURE_RANGE_SIZE;

        /* Reserve address range used for MSI messages */
        if (old_size < MSI_ADDR_BASE_LO &&
            dma_dom->aperture_size > MSI_ADDR_BASE_LO) {
                unsigned long spage;
                int pages;

                pages = iommu_num_pages(MSI_ADDR_BASE_LO, 0x10000, PAGE_SIZE);
                spage = MSI_ADDR_BASE_LO >> PAGE_SHIFT;

                dma_ops_reserve_addresses(dma_dom, spage, pages);
        }

        /* Initialize the exclusion range if necessary */
        for_each_iommu(iommu) {
                if (iommu->exclusion_start &&
                    iommu->exclusion_start >= dma_dom->aperture[index]->offset
                    && iommu->exclusion_start < dma_dom->aperture_size) {
                        unsigned long startpage;
                        int pages = iommu_num_pages(iommu->exclusion_start,
                                                    iommu->exclusion_length,
                                                    PAGE_SIZE);
                        startpage = iommu->exclusion_start >> PAGE_SHIFT;
                        dma_ops_reserve_addresses(dma_dom, startpage, pages);
                }
        }

        /*
         * Check for areas already mapped as present in the new aperture
         * range and mark those pages as reserved in the allocator. Such
         * mappings may already exist as a result of requested unity
         * mappings for devices.
         */
        for (i = dma_dom->aperture[index]->offset;
             i < dma_dom->aperture_size;
             i += PAGE_SIZE) {
                u64 *pte = fetch_pte(&dma_dom->domain, i);
                if (!pte || !IOMMU_PTE_PRESENT(*pte))
                        continue;

                dma_ops_reserve_addresses(dma_dom, i >> PAGE_SHIFT, 1);
        }

        update_domain(&dma_dom->domain);

        return 0;

out_free:
        update_domain(&dma_dom->domain);

        free_page((unsigned long)dma_dom->aperture[index]->bitmap);

        kfree(dma_dom->aperture[index]);
        dma_dom->aperture[index] = NULL;

        return -ENOMEM;
}

static unsigned long dma_ops_area_alloc(struct device *dev,
                                        struct dma_ops_domain *dom,
                                        unsigned int pages,
                                        unsigned long align_mask,
                                        u64 dma_mask,
                                        unsigned long start)
{
        unsigned long next_bit = dom->next_address % APERTURE_RANGE_SIZE;
        int max_index = dom->aperture_size >> APERTURE_RANGE_SHIFT;
        int i = start >> APERTURE_RANGE_SHIFT;
        unsigned long boundary_size;
        unsigned long address = -1;
        unsigned long limit;

        next_bit >>= PAGE_SHIFT;

        boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
                        PAGE_SIZE) >> PAGE_SHIFT;

        for (;i < max_index; ++i) {
                unsigned long offset = dom->aperture[i]->offset >> PAGE_SHIFT;

                if (dom->aperture[i]->offset >= dma_mask)
                        break;

                limit = iommu_device_max_index(APERTURE_RANGE_PAGES, offset,
                                               dma_mask >> PAGE_SHIFT);

                address = iommu_area_alloc(dom->aperture[i]->bitmap,
                                           limit, next_bit, pages, 0,
                                            boundary_size, align_mask);
                if (address != -1) {
                        address = dom->aperture[i]->offset +
                                  (address << PAGE_SHIFT);
                        dom->next_address = address + (pages << PAGE_SHIFT);
                        break;
                }

                next_bit = 0;
        }

        return address;
}

static unsigned long dma_ops_alloc_addresses(struct device *dev,
                                             struct dma_ops_domain *dom,
                                             unsigned int pages,
                                             unsigned long align_mask,
                                             u64 dma_mask)
{
        unsigned long address;

#ifdef CONFIG_IOMMU_STRESS
        dom->next_address = 0;
        dom->need_flush = true;
#endif

        address = dma_ops_area_alloc(dev, dom, pages, align_mask,
                                     dma_mask, dom->next_address);

        if (address == -1) {
                dom->next_address = 0;
                address = dma_ops_area_alloc(dev, dom, pages, align_mask,
                                             dma_mask, 0);
                dom->need_flush = true;
        }

        if (unlikely(address == -1))
                address = DMA_ERROR_CODE;

        WARN_ON((address + (PAGE_SIZE*pages)) > dom->aperture_size);

        return address;
}

/*
 * The address free function.
 *
 * called with domain->lock held
 */
static void dma_ops_free_addresses(struct dma_ops_domain *dom,
                                   unsigned long address,
                                   unsigned int pages)
{
        unsigned i = address >> APERTURE_RANGE_SHIFT;
        struct aperture_range *range = dom->aperture[i];

        BUG_ON(i >= APERTURE_MAX_RANGES || range == NULL);

#ifdef CONFIG_IOMMU_STRESS
        if (i < 4)
                return;
#endif

        if (address >= dom->next_address)
                dom->need_flush = true;

        address = (address % APERTURE_RANGE_SIZE) >> PAGE_SHIFT;

        bitmap_clear(range->bitmap, address, pages);

}

/****************************************************************************
 *
 * The next functions belong to the domain allocation. A domain is
 * allocated for every IOMMU as the default domain. If device isolation
 * is enabled, every device get its own domain. The most important thing
 * about domains is the page table mapping the DMA address space they
 * contain.
 *
 ****************************************************************************/

/*
 * This function adds a protection domain to the global protection domain list
 */
static void add_domain_to_list(struct protection_domain *domain)
{
        unsigned long flags;

        spin_lock_irqsave(&amd_iommu_pd_lock, flags);
        list_add(&domain->list, &amd_iommu_pd_list);
        spin_unlock_irqrestore(&amd_iommu_pd_lock, flags);
}

/*
 * This function removes a protection domain to the global
 * protection domain list
 */
static void del_domain_from_list(struct protection_domain *domain)
{
        unsigned long flags;

        spin_lock_irqsave(&amd_iommu_pd_lock, flags);
        list_del(&domain->list);
        spin_unlock_irqrestore(&amd_iommu_pd_lock, flags);
}

static u16 domain_id_alloc(void)
{
        unsigned long flags;
        int id;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID);
        BUG_ON(id == 0);
        if (id > 0 && id < MAX_DOMAIN_ID)
                __set_bit(id, amd_iommu_pd_alloc_bitmap);
        else
                id = 0;
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        return id;
}

static void domain_id_free(int id)
{
        unsigned long flags;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        if (id > 0 && id < MAX_DOMAIN_ID)
                __clear_bit(id, amd_iommu_pd_alloc_bitmap);
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
}

static void free_pagetable(struct protection_domain *domain)
{
        int i, j;
        u64 *p1, *p2, *p3;

        p1 = domain->pt_root;

        if (!p1)
                return;

        for (i = 0; i < 512; ++i) {
                if (!IOMMU_PTE_PRESENT(p1[i]))
                        continue;

                p2 = IOMMU_PTE_PAGE(p1[i]);
                for (j = 0; j < 512; ++j) {
                        if (!IOMMU_PTE_PRESENT(p2[j]))
                                continue;
                        p3 = IOMMU_PTE_PAGE(p2[j]);
                        free_page((unsigned long)p3);
                }

                free_page((unsigned long)p2);
        }

        free_page((unsigned long)p1);

        domain->pt_root = NULL;
}

static void free_gcr3_tbl_level1(u64 *tbl)
{
        u64 *ptr;
        int i;

        for (i = 0; i < 512; ++i) {
                if (!(tbl[i] & GCR3_VALID))
                        continue;

                ptr = __va(tbl[i] & PAGE_MASK);

                free_page((unsigned long)ptr);
        }
}

static void free_gcr3_tbl_level2(u64 *tbl)
{
        u64 *ptr;
        int i;

        for (i = 0; i < 512; ++i) {
                if (!(tbl[i] & GCR3_VALID))
                        continue;

                ptr = __va(tbl[i] & PAGE_MASK);

                free_gcr3_tbl_level1(ptr);
        }
}

static void free_gcr3_table(struct protection_domain *domain)
{
        if (domain->glx == 2)
                free_gcr3_tbl_level2(domain->gcr3_tbl);
        else if (domain->glx == 1)
                free_gcr3_tbl_level1(domain->gcr3_tbl);
        else if (domain->glx != 0)
                BUG();

        free_page((unsigned long)domain->gcr3_tbl);
}

/*
 * Free a domain, only used if something went wrong in the
 * allocation path and we need to free an already allocated page table
 */
static void dma_ops_domain_free(struct dma_ops_domain *dom)
{
        int i;

        if (!dom)
                return;

        del_domain_from_list(&dom->domain);

        free_pagetable(&dom->domain);

        for (i = 0; i < APERTURE_MAX_RANGES; ++i) {
                if (!dom->aperture[i])
                        continue;
                free_page((unsigned long)dom->aperture[i]->bitmap);
                kfree(dom->aperture[i]);
        }

        kfree(dom);
}

/*
 * Allocates a new protection domain usable for the dma_ops functions.
 * It also initializes the page table and the address allocator data
 * structures required for the dma_ops interface
 */
static struct dma_ops_domain *dma_ops_domain_alloc(void)
{
        struct dma_ops_domain *dma_dom;

        dma_dom = kzalloc(sizeof(struct dma_ops_domain), GFP_KERNEL);
        if (!dma_dom)
                return NULL;

        spin_lock_init(&dma_dom->domain.lock);

        dma_dom->domain.id = domain_id_alloc();
        if (dma_dom->domain.id == 0)
                goto free_dma_dom;
        INIT_LIST_HEAD(&dma_dom->domain.dev_list);
        dma_dom->domain.mode = PAGE_MODE_2_LEVEL;
        dma_dom->domain.pt_root = (void *)get_zeroed_page(GFP_KERNEL);
        dma_dom->domain.flags = PD_DMA_OPS_MASK;
        dma_dom->domain.priv = dma_dom;
        if (!dma_dom->domain.pt_root)
                goto free_dma_dom;

        dma_dom->need_flush = false;
        dma_dom->target_dev = 0xffff;

        add_domain_to_list(&dma_dom->domain);

        if (alloc_new_range(dma_dom, true, GFP_KERNEL))
                goto free_dma_dom;

        /*
         * mark the first page as allocated so we never return 0 as
         * a valid dma-address. So we can use 0 as error value
         */
        dma_dom->aperture[0]->bitmap[0] = 1;
        dma_dom->next_address = 0;


        return dma_dom;

free_dma_dom:
        dma_ops_domain_free(dma_dom);

        return NULL;
}

/*
 * little helper function to check whether a given protection domain is a
 * dma_ops domain
 */
static bool dma_ops_domain(struct protection_domain *domain)
{
        return domain->flags & PD_DMA_OPS_MASK;
}

static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
{
        u64 pte_root = 0;
        u64 flags = 0;

        if (domain->mode != PAGE_MODE_NONE)
                pte_root = virt_to_phys(domain->pt_root);

        pte_root |= (domain->mode & DEV_ENTRY_MODE_MASK)
                    << DEV_ENTRY_MODE_SHIFT;
        pte_root |= IOMMU_PTE_IR | IOMMU_PTE_IW | IOMMU_PTE_P | IOMMU_PTE_TV;

        flags = amd_iommu_dev_table[devid].data[1];

        if (ats)
                flags |= DTE_FLAG_IOTLB;

        if (domain->flags & PD_IOMMUV2_MASK) {
                u64 gcr3 = __pa(domain->gcr3_tbl);
                u64 glx  = domain->glx;
                u64 tmp;

                pte_root |= DTE_FLAG_GV;
                pte_root |= (glx & DTE_GLX_MASK) << DTE_GLX_SHIFT;

                /* First mask out possible old values for GCR3 table */
                tmp = DTE_GCR3_VAL_B(~0ULL) << DTE_GCR3_SHIFT_B;
                flags    &= ~tmp;

                tmp = DTE_GCR3_VAL_C(~0ULL) << DTE_GCR3_SHIFT_C;
                flags    &= ~tmp;

                /* Encode GCR3 table into DTE */
                tmp = DTE_GCR3_VAL_A(gcr3) << DTE_GCR3_SHIFT_A;
                pte_root |= tmp;

                tmp = DTE_GCR3_VAL_B(gcr3) << DTE_GCR3_SHIFT_B;
                flags    |= tmp;

                tmp = DTE_GCR3_VAL_C(gcr3) << DTE_GCR3_SHIFT_C;
                flags    |= tmp;
        }

        flags &= ~(0xffffUL);
        flags |= domain->id;

        amd_iommu_dev_table[devid].data[1]  = flags;
        amd_iommu_dev_table[devid].data[0]  = pte_root;
}

static void clear_dte_entry(u16 devid)
{
        /* remove entry from the device table seen by the hardware */
        amd_iommu_dev_table[devid].data[0] = IOMMU_PTE_P | IOMMU_PTE_TV;
        amd_iommu_dev_table[devid].data[1] = 0;

        amd_iommu_apply_erratum_63(devid);
}

static void do_attach(struct iommu_dev_data *dev_data,
                      struct protection_domain *domain)
{
        struct amd_iommu *iommu;
        bool ats;

        iommu = amd_iommu_rlookup_table[dev_data->devid];
        ats   = dev_data->ats.enabled;

        /* Update data structures */
        dev_data->domain = domain;
        list_add(&dev_data->list, &domain->dev_list);
        set_dte_entry(dev_data->devid, domain, ats);

        /* Do reference counting */
        domain->dev_iommu[iommu->index] += 1;
        domain->dev_cnt                 += 1;

        /* Flush the DTE entry */
        device_flush_dte(dev_data);
}

static void do_detach(struct iommu_dev_data *dev_data)
{
        struct amd_iommu *iommu;

        iommu = amd_iommu_rlookup_table[dev_data->devid];

        /* decrease reference counters */
        dev_data->domain->dev_iommu[iommu->index] -= 1;
        dev_data->domain->dev_cnt                 -= 1;

        /* Update data structures */
        dev_data->domain = NULL;
        list_del(&dev_data->list);
        clear_dte_entry(dev_data->devid);

        /* Flush the DTE entry */
        device_flush_dte(dev_data);
}

/*
 * If a device is not yet associated with a domain, this function does
 * assigns it visible for the hardware
 */
static int __attach_device(struct iommu_dev_data *dev_data,
                           struct protection_domain *domain)
{
        int ret;

        /* lock domain */
        spin_lock(&domain->lock);

        if (dev_data->alias_data != NULL) {
                struct iommu_dev_data *alias_data = dev_data->alias_data;

                /* Some sanity checks */
                ret = -EBUSY;
                if (alias_data->domain != NULL &&
                                alias_data->domain != domain)
                        goto out_unlock;

                if (dev_data->domain != NULL &&
                                dev_data->domain != domain)
                        goto out_unlock;

                /* Do real assignment */
                if (alias_data->domain == NULL)
                        do_attach(alias_data, domain);

                atomic_inc(&alias_data->bind);
        }

        if (dev_data->domain == NULL)
                do_attach(dev_data, domain);

        atomic_inc(&dev_data->bind);

        ret = 0;

out_unlock:

        /* ready */
        spin_unlock(&domain->lock);

        return ret;
}


static void pdev_iommuv2_disable(struct pci_dev *pdev)
{
        pci_disable_ats(pdev);
        pci_disable_pri(pdev);
        pci_disable_pasid(pdev);
}

/* FIXME: Change generic reset-function to do the same */
static int pri_reset_while_enabled(struct pci_dev *pdev)
{
        u16 control;
        int pos;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
        if (!pos)
                return -EINVAL;

        pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
        control |= PCI_PRI_CTRL_RESET;
        pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);

        return 0;
}

static int pdev_iommuv2_enable(struct pci_dev *pdev)
{
        bool reset_enable;
        int reqs, ret;

        /* FIXME: Hardcode number of outstanding requests for now */
        reqs = 32;
        if (pdev_pri_erratum(pdev, AMD_PRI_DEV_ERRATUM_LIMIT_REQ_ONE))
                reqs = 1;
        reset_enable = pdev_pri_erratum(pdev, AMD_PRI_DEV_ERRATUM_ENABLE_RESET);

        /* Only allow access to user-accessible pages */
        ret = pci_enable_pasid(pdev, 0);
        if (ret)
                goto out_err;

        /* First reset the PRI state of the device */
        ret = pci_reset_pri(pdev);
        if (ret)
                goto out_err;

        /* Enable PRI */
        ret = pci_enable_pri(pdev, reqs);
        if (ret)
                goto out_err;

        if (reset_enable) {
                ret = pri_reset_while_enabled(pdev);
                if (ret)
                        goto out_err;
        }

        ret = pci_enable_ats(pdev, PAGE_SHIFT);
        if (ret)
                goto out_err;

        return 0;

out_err:
        pci_disable_pri(pdev);
        pci_disable_pasid(pdev);

        return ret;
}

/* FIXME: Move this to PCI code */
#define PCI_PRI_TLP_OFF         (1 << 15)

static bool pci_pri_tlp_required(struct pci_dev *pdev)
{
        u16 status;
        int pos;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
        if (!pos)
                return false;

        pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);

        return (status & PCI_PRI_TLP_OFF) ? true : false;
}

/*
 * If a device is not yet associated with a domain, this function
 * assigns it visible for the hardware
 */
static int attach_device(struct device *dev,
                         struct protection_domain *domain)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct iommu_dev_data *dev_data;
        unsigned long flags;
        int ret;

        dev_data = get_dev_data(dev);

        if (domain->flags & PD_IOMMUV2_MASK) {
                if (!dev_data->iommu_v2 || !dev_data->passthrough)
                        return -EINVAL;

                if (pdev_iommuv2_enable(pdev) != 0)
                        return -EINVAL;

                dev_data->ats.enabled = true;
                dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
                dev_data->pri_tlp     = pci_pri_tlp_required(pdev);
        } else if (amd_iommu_iotlb_sup &&
                   pci_enable_ats(pdev, PAGE_SHIFT) == 0) {
                dev_data->ats.enabled = true;
                dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
        }

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        ret = __attach_device(dev_data, domain);
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        /*
         * We might boot into a crash-kernel here. The crashed kernel
         * left the caches in the IOMMU dirty. So we have to flush
         * here to evict all dirty stuff.
         */
        domain_flush_tlb_pde(domain);

        return ret;
}

/*
 * Removes a device from a protection domain (unlocked)
 */
static void __detach_device(struct iommu_dev_data *dev_data)
{
        struct protection_domain *domain;
        unsigned long flags;

        BUG_ON(!dev_data->domain);

        domain = dev_data->domain;

        spin_lock_irqsave(&domain->lock, flags);

        if (dev_data->alias_data != NULL) {
                struct iommu_dev_data *alias_data = dev_data->alias_data;

                if (atomic_dec_and_test(&alias_data->bind))
                        do_detach(alias_data);
        }

        if (atomic_dec_and_test(&dev_data->bind))
                do_detach(dev_data);

        spin_unlock_irqrestore(&domain->lock, flags);

        /*
         * If we run in passthrough mode the device must be assigned to the
         * passthrough domain if it is detached from any other domain.
         * Make sure we can deassign from the pt_domain itself.
         */
        if (dev_data->passthrough &&
            (dev_data->domain == NULL && domain != pt_domain))
                __attach_device(dev_data, pt_domain);
}

/*
 * Removes a device from a protection domain (with devtable_lock held)
 */
static void detach_device(struct device *dev)
{
        struct protection_domain *domain;
        struct iommu_dev_data *dev_data;
        unsigned long flags;

        dev_data = get_dev_data(dev);
        domain   = dev_data->domain;

        /* lock device table */
        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        __detach_device(dev_data);
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        if (domain->flags & PD_IOMMUV2_MASK)
                pdev_iommuv2_disable(to_pci_dev(dev));
        else if (dev_data->ats.enabled)
                pci_disable_ats(to_pci_dev(dev));

        dev_data->ats.enabled = false;
}

/*
 * Find out the protection domain structure for a given PCI device. This
 * will give us the pointer to the page table root for example.
 */
static struct protection_domain *domain_for_device(struct device *dev)
{
        struct iommu_dev_data *dev_data;
        struct protection_domain *dom = NULL;
        unsigned long flags;

        dev_data   = get_dev_data(dev);

        if (dev_data->domain)
                return dev_data->domain;

        if (dev_data->alias_data != NULL) {
                struct iommu_dev_data *alias_data = dev_data->alias_data;

                read_lock_irqsave(&amd_iommu_devtable_lock, flags);
                if (alias_data->domain != NULL) {
                        __attach_device(dev_data, alias_data->domain);
                        dom = alias_data->domain;
                }
                read_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
        }

        return dom;
}

static int device_change_notifier(struct notifier_block *nb,
                                  unsigned long action, void *data)
{
        struct dma_ops_domain *dma_domain;
        struct protection_domain *domain;
        struct iommu_dev_data *dev_data;
        struct device *dev = data;
        struct amd_iommu *iommu;
        unsigned long flags;
        u16 devid;

        if (!check_device(dev))
                return 0;

        devid    = get_device_id(dev);
        iommu    = amd_iommu_rlookup_table[devid];
        dev_data = get_dev_data(dev);

        switch (action) {
        case BUS_NOTIFY_UNBOUND_DRIVER:

                domain = domain_for_device(dev);

                if (!domain)
                        goto out;
                if (dev_data->passthrough)
                        break;
                detach_device(dev);
                break;
        case BUS_NOTIFY_ADD_DEVICE:

                iommu_init_device(dev);

                /*
                 * dev_data is still NULL and
                 * got initialized in iommu_init_device
                 */
                dev_data = get_dev_data(dev);

                if (iommu_pass_through || dev_data->iommu_v2) {
                        dev_data->passthrough = true;
                        attach_device(dev, pt_domain);
                        break;
                }

                domain = domain_for_device(dev);

                /* allocate a protection domain if a device is added */
                dma_domain = find_protection_domain(devid);
                if (!dma_domain) {
                        dma_domain = dma_ops_domain_alloc();
                        if (!dma_domain)
                                goto out;
                        dma_domain->target_dev = devid;

                        spin_lock_irqsave(&iommu_pd_list_lock, flags);
                        list_add_tail(&dma_domain->list, &iommu_pd_list);
                        spin_unlock_irqrestore(&iommu_pd_list_lock, flags);
                }

                dev->archdata.dma_ops = &amd_iommu_dma_ops;

                break;
        case BUS_NOTIFY_DEL_DEVICE:

                iommu_uninit_device(dev);

        default:
                goto out;
        }

        iommu_completion_wait(iommu);

out:
        return 0;
}

static struct notifier_block device_nb = {
        .notifier_call = device_change_notifier,
};

void amd_iommu_init_notifier(void)
{
        bus_register_notifier(&pci_bus_type, &device_nb);
}

/*****************************************************************************
 *
 * The next functions belong to the dma_ops mapping/unmapping code.
 *
 *****************************************************************************/

/*
 * In the dma_ops path we only have the struct device. This function
 * finds the corresponding IOMMU, the protection domain and the
 * requestor id for a given device.
 * If the device is not yet associated with a domain this is also done
 * in this function.
 */
static struct protection_domain *get_domain(struct device *dev)
{
        struct protection_domain *domain;
        struct dma_ops_domain *dma_dom;
        u16 devid = get_device_id(dev);

        if (!check_device(dev))
                return ERR_PTR(-EINVAL);

        domain = domain_for_device(dev);
        if (domain != NULL && !dma_ops_domain(domain))
                return ERR_PTR(-EBUSY);

        if (domain != NULL)
                return domain;

        /* Device not bound yet - bind it */
        dma_dom = find_protection_domain(devid);
        if (!dma_dom)
                dma_dom = amd_iommu_rlookup_table[devid]->default_dom;
        attach_device(dev, &dma_dom->domain);
        DUMP_printk("Using protection domain %d for device %s\n",
                    dma_dom->domain.id, dev_name(dev));

        return &dma_dom->domain;
}

static void update_device_table(struct protection_domain *domain)
{
        struct iommu_dev_data *dev_data;

        list_for_each_entry(dev_data, &domain->dev_list, list)
                set_dte_entry(dev_data->devid, domain, dev_data->ats.enabled);
}

static void update_domain(struct protection_domain *domain)
{
        if (!domain->updated)
                return;

        update_device_table(domain);

        domain_flush_devices(domain);
        domain_flush_tlb_pde(domain);

        domain->updated = false;
}

/*
 * This function fetches the PTE for a given address in the aperture
 */
static u64* dma_ops_get_pte(struct dma_ops_domain *dom,
                            unsigned long address)
{
        struct aperture_range *aperture;
        u64 *pte, *pte_page;

        aperture = dom->aperture[APERTURE_RANGE_INDEX(address)];
        if (!aperture)
                return NULL;

        pte = aperture->pte_pages[APERTURE_PAGE_INDEX(address)];
        if (!pte) {
                pte = alloc_pte(&dom->domain, address, PAGE_SIZE, &pte_page,
                                GFP_ATOMIC);
                aperture->pte_pages[APERTURE_PAGE_INDEX(address)] = pte_page;
        } else
                pte += PM_LEVEL_INDEX(0, address);

        update_domain(&dom->domain);

        return pte;
}

/*
 * This is the generic map function. It maps one 4kb page at paddr to
 * the given address in the DMA address space for the domain.
 */
static dma_addr_t dma_ops_domain_map(struct dma_ops_domain *dom,
                                     unsigned long address,
                                     phys_addr_t paddr,
                                     int direction)
{
        u64 *pte, __pte;

        WARN_ON(address > dom->aperture_size);

        paddr &= PAGE_MASK;

        pte  = dma_ops_get_pte(dom, address);
        if (!pte)
                return DMA_ERROR_CODE;

        __pte = paddr | IOMMU_PTE_P | IOMMU_PTE_FC;

        if (direction == DMA_TO_DEVICE)
                __pte |= IOMMU_PTE_IR;
        else if (direction == DMA_FROM_DEVICE)
                __pte |= IOMMU_PTE_IW;
        else if (direction == DMA_BIDIRECTIONAL)
                __pte |= IOMMU_PTE_IR | IOMMU_PTE_IW;

        WARN_ON(*pte);

        *pte = __pte;

        return (dma_addr_t)address;
}

/*
 * The generic unmapping function for on page in the DMA address space.
 */
static void dma_ops_domain_unmap(struct dma_ops_domain *dom,
                                 unsigned long address)
{
        struct aperture_range *aperture;
        u64 *pte;

        if (address >= dom->aperture_size)
                return;

        aperture = dom->aperture[APERTURE_RANGE_INDEX(address)];
        if (!aperture)
                return;

        pte  = aperture->pte_pages[APERTURE_PAGE_INDEX(address)];
        if (!pte)
                return;

        pte += PM_LEVEL_INDEX(0, address);

        WARN_ON(!*pte);

        *pte = 0ULL;
}

/*
 * This function contains common code for mapping of a physically
 * contiguous memory region into DMA address space. It is used by all
 * mapping functions provided with this IOMMU driver.
 * Must be called with the domain lock held.
 */
static dma_addr_t __map_single(struct device *dev,
                               struct dma_ops_domain *dma_dom,
                               phys_addr_t paddr,
                               size_t size,
                               int dir,
                               bool align,
                               u64 dma_mask)
{
        dma_addr_t offset = paddr & ~PAGE_MASK;
        dma_addr_t address, start, ret;
        unsigned int pages;
        unsigned long align_mask = 0;
        int i;

        pages = iommu_num_pages(paddr, size, PAGE_SIZE);
        paddr &= PAGE_MASK;

        INC_STATS_COUNTER(total_map_requests);

        if (pages > 1)
                INC_STATS_COUNTER(cross_page);

        if (align)
                align_mask = (1UL << get_order(size)) - 1;

retry:
        address = dma_ops_alloc_addresses(dev, dma_dom, pages, align_mask,
                                          dma_mask);
        if (unlikely(address == DMA_ERROR_CODE)) {
                /*
                 * setting next_address here will let the address
                 * allocator only scan the new allocated range in the
                 * first run. This is a small optimization.
                 */
                dma_dom->next_address = dma_dom->aperture_size;

                if (alloc_new_range(dma_dom, false, GFP_ATOMIC))
                        goto out;

                /*
                 * aperture was successfully enlarged by 128 MB, try
                 * allocation again
                 */
                goto retry;
        }

        start = address;
        for (i = 0; i < pages; ++i) {
                ret = dma_ops_domain_map(dma_dom, start, paddr, dir);
                if (ret == DMA_ERROR_CODE)
                        goto out_unmap;

                paddr += PAGE_SIZE;
                start += PAGE_SIZE;
        }
        address += offset;

        ADD_STATS_COUNTER(alloced_io_mem, size);

        if (unlikely(dma_dom->need_flush && !amd_iommu_unmap_flush)) {
                domain_flush_tlb(&dma_dom->domain);
                dma_dom->need_flush = false;
        } else if (unlikely(amd_iommu_np_cache))
                domain_flush_pages(&dma_dom->domain, address, size);

out:
        return address;

out_unmap:

        for (--i; i >= 0; --i) {
                start -= PAGE_SIZE;
                dma_ops_domain_unmap(dma_dom, start);
        }

        dma_ops_free_addresses(dma_dom, address, pages);

        return DMA_ERROR_CODE;
}

/*
 * Does the reverse of the __map_single function. Must be called with
 * the domain lock held too
 */
static void __unmap_single(struct dma_ops_domain *dma_dom,
                           dma_addr_t dma_addr,
                           size_t size,
                           int dir)
{
        dma_addr_t flush_addr;
        dma_addr_t i, start;
        unsigned int pages;

        if ((dma_addr == DMA_ERROR_CODE) ||
            (dma_addr + size > dma_dom->aperture_size))
                return;

        flush_addr = dma_addr;
        pages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
        dma_addr &= PAGE_MASK;
        start = dma_addr;

        for (i = 0; i < pages; ++i) {
                dma_ops_domain_unmap(dma_dom, start);
                start += PAGE_SIZE;
        }

        SUB_STATS_COUNTER(alloced_io_mem, size);

        dma_ops_free_addresses(dma_dom, dma_addr, pages);

        if (amd_iommu_unmap_flush || dma_dom->need_flush) {
                domain_flush_pages(&dma_dom->domain, flush_addr, size);
                dma_dom->need_flush = false;
        }
}

/*
 * The exported map_single function for dma_ops.
 */
static dma_addr_t map_page(struct device *dev, struct page *page,
                           unsigned long offset, size_t size,
                           enum dma_data_direction dir,
                           struct dma_attrs *attrs)
{
        unsigned long flags;
        struct protection_domain *domain;
        dma_addr_t addr;
        u64 dma_mask;
        phys_addr_t paddr = page_to_phys(page) + offset;

        INC_STATS_COUNTER(cnt_map_single);

        domain = get_domain(dev);
        if (PTR_ERR(domain) == -EINVAL)
                return (dma_addr_t)paddr;
        else if (IS_ERR(domain))
                return DMA_ERROR_CODE;

        dma_mask = *dev->dma_mask;

        spin_lock_irqsave(&domain->lock, flags);

        addr = __map_single(dev, domain->priv, paddr, size, dir, false,
                            dma_mask);
        if (addr == DMA_ERROR_CODE)
                goto out;

        domain_flush_complete(domain);

out:
        spin_unlock_irqrestore(&domain->lock, flags);

        return addr;
}

/*
 * The exported unmap_single function for dma_ops.
 */
static void unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
                       enum dma_data_direction dir, struct dma_attrs *attrs)
{
        unsigned long flags;
        struct protection_domain *domain;

        INC_STATS_COUNTER(cnt_unmap_single);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return;

        spin_lock_irqsave(&domain->lock, flags);

        __unmap_single(domain->priv, dma_addr, size, dir);

        domain_flush_complete(domain);

        spin_unlock_irqrestore(&domain->lock, flags);
}

/*
 * The exported map_sg function for dma_ops (handles scatter-gather
 * lists).
 */
static int map_sg(struct device *dev, struct scatterlist *sglist,
                  int nelems, enum dma_data_direction dir,
                  struct dma_attrs *attrs)
{
        unsigned long flags;
        struct protection_domain *domain;
        int i;
        struct scatterlist *s;
        phys_addr_t paddr;
        int mapped_elems = 0;
        u64 dma_mask;

        INC_STATS_COUNTER(cnt_map_sg);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return 0;

        dma_mask = *dev->dma_mask;

        spin_lock_irqsave(&domain->lock, flags);

        for_each_sg(sglist, s, nelems, i) {
                paddr = sg_phys(s);

                s->dma_address = __map_single(dev, domain->priv,
                                              paddr, s->length, dir, false,
                                              dma_mask);

                if (s->dma_address) {
                        s->dma_length = s->length;
                        mapped_elems++;
                } else
                        goto unmap;
        }

        domain_flush_complete(domain);

out:
        spin_unlock_irqrestore(&domain->lock, flags);

        return mapped_elems;
unmap:
        for_each_sg(sglist, s, mapped_elems, i) {
                if (s->dma_address)
                        __unmap_single(domain->priv, s->dma_address,
                                       s->dma_length, dir);
                s->dma_address = s->dma_length = 0;
        }

        mapped_elems = 0;

        goto out;
}

/*
 * The exported map_sg function for dma_ops (handles scatter-gather
 * lists).
 */
static void unmap_sg(struct device *dev, struct scatterlist *sglist,
                     int nelems, enum dma_data_direction dir,
                     struct dma_attrs *attrs)
{
        unsigned long flags;
        struct protection_domain *domain;
        struct scatterlist *s;
        int i;

        INC_STATS_COUNTER(cnt_unmap_sg);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return;

        spin_lock_irqsave(&domain->lock, flags);

        for_each_sg(sglist, s, nelems, i) {
                __unmap_single(domain->priv, s->dma_address,
                               s->dma_length, dir);
                s->dma_address = s->dma_length = 0;
        }

        domain_flush_complete(domain);

        spin_unlock_irqrestore(&domain->lock, flags);
}

/*
 * The exported alloc_coherent function for dma_ops.
 */
static void *alloc_coherent(struct device *dev, size_t size,
                            dma_addr_t *dma_addr, gfp_t flag,
                            struct dma_attrs *attrs)
{
        unsigned long flags;
        void *virt_addr;
        struct protection_domain *domain;
        phys_addr_t paddr;
        u64 dma_mask = dev->coherent_dma_mask;

        INC_STATS_COUNTER(cnt_alloc_coherent);

        domain = get_domain(dev);
        if (PTR_ERR(domain) == -EINVAL) {
                virt_addr = (void *)__get_free_pages(flag, get_order(size));
                *dma_addr = __pa(virt_addr);
                return virt_addr;
        } else if (IS_ERR(domain))
                return NULL;

        dma_mask  = dev->coherent_dma_mask;
        flag     &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
        flag     |= __GFP_ZERO;

        virt_addr = (void *)__get_free_pages(flag, get_order(size));
        if (!virt_addr)
                return NULL;

        paddr = virt_to_phys(virt_addr);

        if (!dma_mask)
                dma_mask = *dev->dma_mask;

        spin_lock_irqsave(&domain->lock, flags);

        *dma_addr = __map_single(dev, domain->priv, paddr,
                                 size, DMA_BIDIRECTIONAL, true, dma_mask);

        if (*dma_addr == DMA_ERROR_CODE) {
                spin_unlock_irqrestore(&domain->lock, flags);
                goto out_free;
        }

        domain_flush_complete(domain);

        spin_unlock_irqrestore(&domain->lock, flags);

        return virt_addr;

out_free:

        free_pages((unsigned long)virt_addr, get_order(size));

        return NULL;
}

/*
 * The exported free_coherent function for dma_ops.
 */
static void free_coherent(struct device *dev, size_t size,
                          void *virt_addr, dma_addr_t dma_addr,
                          struct dma_attrs *attrs)
{
        unsigned long flags;
        struct protection_domain *domain;

        INC_STATS_COUNTER(cnt_free_coherent);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                goto free_mem;

        spin_lock_irqsave(&domain->lock, flags);

        __unmap_single(domain->priv, dma_addr, size, DMA_BIDIRECTIONAL);

        domain_flush_complete(domain);

        spin_unlock_irqrestore(&domain->lock, flags);

free_mem:
        free_pages((unsigned long)virt_addr, get_order(size));
}

/*
 * This function is called by the DMA layer to find out if we can handle a
 * particular device. It is part of the dma_ops.
 */
static int amd_iommu_dma_supported(struct device *dev, u64 mask)
{
        return check_device(dev);
}

/*
 * The function for pre-allocating protection domains.
 *
 * If the driver core informs the DMA layer if a driver grabs a device
 * we don't need to preallocate the protection domains anymore.
 * For now we have to.
 */
static void __init prealloc_protection_domains(void)
{
        struct iommu_dev_data *dev_data;
        struct dma_ops_domain *dma_dom;
        struct pci_dev *dev = NULL;
        u16 devid;

        for_each_pci_dev(dev) {

                /* Do we handle this device? */
                if (!check_device(&dev->dev))
                        continue;

                dev_data = get_dev_data(&dev->dev);
                if (!amd_iommu_force_isolation && dev_data->iommu_v2) {
                        /* Make sure passthrough domain is allocated */
                        alloc_passthrough_domain();
                        dev_data->passthrough = true;
                        attach_device(&dev->dev, pt_domain);
                        pr_info("AMD-Vi: Using passthrough domain for device %s\n",
                                dev_name(&dev->dev));
                }

                /* Is there already any domain for it? */
                if (domain_for_device(&dev->dev))
                        continue;

                devid = get_device_id(&dev->dev);

                dma_dom = dma_ops_domain_alloc();
                if (!dma_dom)
                        continue;
                init_unity_mappings_for_device(dma_dom, devid);
                dma_dom->target_dev = devid;

                attach_device(&dev->dev, &dma_dom->domain);

                list_add_tail(&dma_dom->list, &iommu_pd_list);
        }
}

static struct dma_map_ops amd_iommu_dma_ops = {
        .alloc = alloc_coherent,
        .free = free_coherent,
        .map_page = map_page,
        .unmap_page = unmap_page,
        .map_sg = map_sg,
        .unmap_sg = unmap_sg,
        .dma_supported = amd_iommu_dma_supported,
};

static unsigned device_dma_ops_init(void)
{
        struct iommu_dev_data *dev_data;
        struct pci_dev *pdev = NULL;
        unsigned unhandled = 0;

        for_each_pci_dev(pdev) {
                if (!check_device(&pdev->dev)) {

                        iommu_ignore_device(&pdev->dev);

                        unhandled += 1;
                        continue;
                }

                dev_data = get_dev_data(&pdev->dev);

                if (!dev_data->passthrough)
                        pdev->dev.archdata.dma_ops = &amd_iommu_dma_ops;
                else
                        pdev->dev.archdata.dma_ops = &nommu_dma_ops;
        }

        return unhandled;
}

/*
 * The function which clues the AMD IOMMU driver into dma_ops.
 */

void __init amd_iommu_init_api(void)
{
        bus_set_iommu(&pci_bus_type, &amd_iommu_ops);
}

int __init amd_iommu_init_dma_ops(void)
{
        struct amd_iommu *iommu;
        int ret, unhandled;

        /*
         * first allocate a default protection domain for every IOMMU we
         * found in the system. Devices not assigned to any other
         * protection domain will be assigned to the default one.
         */
        for_each_iommu(iommu) {
                iommu->default_dom = dma_ops_domain_alloc();
                if (iommu->default_dom == NULL)
                        return -ENOMEM;
                iommu->default_dom->domain.flags |= PD_DEFAULT_MASK;
                ret = iommu_init_unity_mappings(iommu);
                if (ret)
                        goto free_domains;
        }

        /*
         * Pre-allocate the protection domains for each device.
         */
        prealloc_protection_domains();

        iommu_detected = 1;
        swiotlb = 0;

        /* Make the driver finally visible to the drivers */
        unhandled = device_dma_ops_init();
        if (unhandled && max_pfn > MAX_DMA32_PFN) {
                /* There are unhandled devices - initialize swiotlb for them */
                swiotlb = 1;
        }

        amd_iommu_stats_init();

        if (amd_iommu_unmap_flush)
                pr_info("AMD-Vi: IO/TLB flush on unmap enabled\n");
        else
                pr_info("AMD-Vi: Lazy IO/TLB flushing enabled\n");

        return 0;

free_domains:

        for_each_iommu(iommu) {
                dma_ops_domain_free(iommu->default_dom);
        }

        return ret;
}

/*****************************************************************************
 *
 * The following functions belong to the exported interface of AMD IOMMU
 *
 * This interface allows access to lower level functions of the IOMMU
 * like protection domain handling and assignement of devices to domains
 * which is not possible with the dma_ops interface.
 *
 *****************************************************************************/

static void cleanup_domain(struct protection_domain *domain)
{
        struct iommu_dev_data *dev_data, *next;
        unsigned long flags;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);

        list_for_each_entry_safe(dev_data, next, &domain->dev_list, list) {
                __detach_device(dev_data);
                atomic_set(&dev_data->bind, 0);
        }

        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
}

static void protection_domain_free(struct protection_domain *domain)
{
        if (!domain)
                return;

        del_domain_from_list(domain);

        if (domain->id)
                domain_id_free(domain->id);

        kfree(domain);
}

static struct protection_domain *protection_domain_alloc(void)
{
        struct protection_domain *domain;

        domain = kzalloc(sizeof(*domain), GFP_KERNEL);
        if (!domain)
                return NULL;

        spin_lock_init(&domain->lock);
        mutex_init(&domain->api_lock);
        domain->id = domain_id_alloc();
        if (!domain->id)
                goto out_err;
        INIT_LIST_HEAD(&domain->dev_list);

        add_domain_to_list(domain);

        return domain;

out_err:
        kfree(domain);

        return NULL;
}

static int __init alloc_passthrough_domain(void)
{
        if (pt_domain != NULL)
                return 0;

        /* allocate passthrough domain */
        pt_domain = protection_domain_alloc();
        if (!pt_domain)
                return -ENOMEM;

        pt_domain->mode = PAGE_MODE_NONE;

        return 0;
}
static int amd_iommu_domain_init(struct iommu_domain *dom)
{
        struct protection_domain *domain;

        domain = protection_domain_alloc();
        if (!domain)
                goto out_free;

        domain->mode    = PAGE_MODE_3_LEVEL;
        domain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
        if (!domain->pt_root)
                goto out_free;

        domain->iommu_domain = dom;

        dom->priv = domain;

        dom->geometry.aperture_start = 0;
        dom->geometry.aperture_end   = ~0ULL;
        dom->geometry.force_aperture = true;

        return 0;

out_free:
        protection_domain_free(domain);

        return -ENOMEM;
}

static void amd_iommu_domain_destroy(struct iommu_domain *dom)
{
        struct protection_domain *domain = dom->priv;

        if (!domain)
                return;

        if (domain->dev_cnt > 0)
                cleanup_domain(domain);

        BUG_ON(domain->dev_cnt != 0);

        if (domain->mode != PAGE_MODE_NONE)
                free_pagetable(domain);

        if (domain->flags & PD_IOMMUV2_MASK)
                free_gcr3_table(domain);

        protection_domain_free(domain);

        dom->priv = NULL;
}

static void amd_iommu_detach_device(struct iommu_domain *dom,
                                    struct device *dev)
{
        struct iommu_dev_data *dev_data = dev->archdata.iommu;
        struct amd_iommu *iommu;
        u16 devid;

        if (!check_device(dev))
                return;

        devid = get_device_id(dev);

        if (dev_data->domain != NULL)
                detach_device(dev);

        iommu = amd_iommu_rlookup_table[devid];
        if (!iommu)
                return;

        iommu_completion_wait(iommu);
}

static int amd_iommu_attach_device(struct iommu_domain *dom,
                                   struct device *dev)
{
        struct protection_domain *domain = dom->priv;
        struct iommu_dev_data *dev_data;
        struct amd_iommu *iommu;
        int ret;

        if (!check_device(dev))
                return -EINVAL;

        dev_data = dev->archdata.iommu;

        iommu = amd_iommu_rlookup_table[dev_data->devid];
        if (!iommu)
                return -EINVAL;

        if (dev_data->domain)
                detach_device(dev);

        ret = attach_device(dev, domain);

        iommu_completion_wait(iommu);

        return ret;
}

static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
                         phys_addr_t paddr, size_t page_size, int iommu_prot)
{
        struct protection_domain *domain = dom->priv;
        int prot = 0;
        int ret;

        if (domain->mode == PAGE_MODE_NONE)
                return -EINVAL;

        if (iommu_prot & IOMMU_READ)
                prot |= IOMMU_PROT_IR;
        if (iommu_prot & IOMMU_WRITE)
                prot |= IOMMU_PROT_IW;

        mutex_lock(&domain->api_lock);
        ret = iommu_map_page(domain, iova, paddr, prot, page_size);
        mutex_unlock(&domain->api_lock);

        return ret;
}

static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
                           size_t page_size)
{
        struct protection_domain *domain = dom->priv;
        size_t unmap_size;

        if (domain->mode == PAGE_MODE_NONE)
                return -EINVAL;

        mutex_lock(&domain->api_lock);
        unmap_size = iommu_unmap_page(domain, iova, page_size);
        mutex_unlock(&domain->api_lock);

        domain_flush_tlb_pde(domain);

        return unmap_size;
}

static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
                                          dma_addr_t iova)
{
        struct protection_domain *domain = dom->priv;
        unsigned long offset_mask;
        phys_addr_t paddr;
        u64 *pte, __pte;

        if (domain->mode == PAGE_MODE_NONE)
                return iova;

        pte = fetch_pte(domain, iova);

        if (!pte || !IOMMU_PTE_PRESENT(*pte))
                return 0;

        if (PM_PTE_LEVEL(*pte) == 0)
                offset_mask = PAGE_SIZE - 1;
        else
                offset_mask = PTE_PAGE_SIZE(*pte) - 1;

        __pte = *pte & PM_ADDR_MASK;
        paddr = (__pte & ~offset_mask) | (iova & offset_mask);

        return paddr;
}

static int amd_iommu_domain_has_cap(struct iommu_domain *domain,
                                    unsigned long cap)
{
        switch (cap) {
        case IOMMU_CAP_CACHE_COHERENCY:
                return 1;
        case IOMMU_CAP_INTR_REMAP:
                return irq_remapping_enabled;
        }

        return 0;
}

static struct iommu_ops amd_iommu_ops = {
        .domain_init = amd_iommu_domain_init,
        .domain_destroy = amd_iommu_domain_destroy,
        .attach_dev = amd_iommu_attach_device,
        .detach_dev = amd_iommu_detach_device,
        .map = amd_iommu_map,
        .unmap = amd_iommu_unmap,
        .iova_to_phys = amd_iommu_iova_to_phys,
        .domain_has_cap = amd_iommu_domain_has_cap,
        .pgsize_bitmap  = AMD_IOMMU_PGSIZES,
};

/*****************************************************************************
 *
 * The next functions do a basic initialization of IOMMU for pass through
 * mode
 *
 * In passthrough mode the IOMMU is initialized and enabled but not used for
 * DMA-API translation.
 *
 *****************************************************************************/

int __init amd_iommu_init_passthrough(void)
{
        struct iommu_dev_data *dev_data;
        struct pci_dev *dev = NULL;
        struct amd_iommu *iommu;
        u16 devid;
        int ret;

        ret = alloc_passthrough_domain();
        if (ret)
                return ret;

        for_each_pci_dev(dev) {
                if (!check_device(&dev->dev))
                        continue;

                dev_data = get_dev_data(&dev->dev);
                dev_data->passthrough = true;

                devid = get_device_id(&dev->dev);

                iommu = amd_iommu_rlookup_table[devid];
                if (!iommu)
                        continue;

                attach_device(&dev->dev, pt_domain);
        }

        amd_iommu_stats_init();

        pr_info("AMD-Vi: Initialized for Passthrough Mode\n");

        return 0;
}

/* IOMMUv2 specific functions */
int amd_iommu_register_ppr_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&ppr_notifier, nb);
}
EXPORT_SYMBOL(amd_iommu_register_ppr_notifier);

int amd_iommu_unregister_ppr_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&ppr_notifier, nb);
}
EXPORT_SYMBOL(amd_iommu_unregister_ppr_notifier);

void amd_iommu_domain_direct_map(struct iommu_domain *dom)
{
        struct protection_domain *domain = dom->priv;
        unsigned long flags;

        spin_lock_irqsave(&domain->lock, flags);

        /* Update data structure */
        domain->mode    = PAGE_MODE_NONE;
        domain->updated = true;

        /* Make changes visible to IOMMUs */
        update_domain(domain);

        /* Page-table is not visible to IOMMU anymore, so free it */
        free_pagetable(domain);

        spin_unlock_irqrestore(&domain->lock, flags);
}
EXPORT_SYMBOL(amd_iommu_domain_direct_map);

int amd_iommu_domain_enable_v2(struct iommu_domain *dom, int pasids)
{
        struct protection_domain *domain = dom->priv;
        unsigned long flags;
        int levels, ret;

        if (pasids <= 0 || pasids > (PASID_MASK + 1))
                return -EINVAL;

        /* Number of GCR3 table levels required */
        for (levels = 0; (pasids - 1) & ~0x1ff; pasids >>= 9)
                levels += 1;

        if (levels > amd_iommu_max_glx_val)
                return -EINVAL;

        spin_lock_irqsave(&domain->lock, flags);

        /*
         * Save us all sanity checks whether devices already in the
         * domain support IOMMUv2. Just force that the domain has no
         * devices attached when it is switched into IOMMUv2 mode.
         */
        ret = -EBUSY;
        if (domain->dev_cnt > 0 || domain->flags & PD_IOMMUV2_MASK)
                goto out;

        ret = -ENOMEM;
        domain->gcr3_tbl = (void *)get_zeroed_page(GFP_ATOMIC);
        if (domain->gcr3_tbl == NULL)
                goto out;

        domain->glx      = levels;
        domain->flags   |= PD_IOMMUV2_MASK;
        domain->updated  = true;

        update_domain(domain);

        ret = 0;

out:
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_domain_enable_v2);

static int __flush_pasid(struct protection_domain *domain, int pasid,
                         u64 address, bool size)
{
        struct iommu_dev_data *dev_data;
        struct iommu_cmd cmd;
        int i, ret;

        if (!(domain->flags & PD_IOMMUV2_MASK))
                return -EINVAL;

        build_inv_iommu_pasid(&cmd, domain->id, pasid, address, size);

        /*
         * IOMMU TLB needs to be flushed before Device TLB to
         * prevent device TLB refill from IOMMU TLB
         */
        for (i = 0; i < amd_iommus_present; ++i) {
                if (domain->dev_iommu[i] == 0)
                        continue;

                ret = iommu_queue_command(amd_iommus[i], &cmd);
                if (ret != 0)
                        goto out;
        }

        /* Wait until IOMMU TLB flushes are complete */
        domain_flush_complete(domain);

        /* Now flush device TLBs */
        list_for_each_entry(dev_data, &domain->dev_list, list) {
                struct amd_iommu *iommu;
                int qdep;

                BUG_ON(!dev_data->ats.enabled);

                qdep  = dev_data->ats.qdep;
                iommu = amd_iommu_rlookup_table[dev_data->devid];

                build_inv_iotlb_pasid(&cmd, dev_data->devid, pasid,
                                      qdep, address, size);

                ret = iommu_queue_command(iommu, &cmd);
                if (ret != 0)
                        goto out;
        }

        /* Wait until all device TLBs are flushed */
        domain_flush_complete(domain);

        ret = 0;

out:

        return ret;
}

static int __amd_iommu_flush_page(struct protection_domain *domain, int pasid,
                                  u64 address)
{
        INC_STATS_COUNTER(invalidate_iotlb);

        return __flush_pasid(domain, pasid, address, false);
}

int amd_iommu_flush_page(struct iommu_domain *dom, int pasid,
                         u64 address)
{
        struct protection_domain *domain = dom->priv;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __amd_iommu_flush_page(domain, pasid, address);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_flush_page);

static int __amd_iommu_flush_tlb(struct protection_domain *domain, int pasid)
{
        INC_STATS_COUNTER(invalidate_iotlb_all);

        return __flush_pasid(domain, pasid, CMD_INV_IOMMU_ALL_PAGES_ADDRESS,
                             true);
}

int amd_iommu_flush_tlb(struct iommu_domain *dom, int pasid)
{
        struct protection_domain *domain = dom->priv;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __amd_iommu_flush_tlb(domain, pasid);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_flush_tlb);

static u64 *__get_gcr3_pte(u64 *root, int level, int pasid, bool alloc)
{
        int index;
        u64 *pte;

        while (true) {

                index = (pasid >> (9 * level)) & 0x1ff;
                pte   = &root[index];

                if (level == 0)
                        break;

                if (!(*pte & GCR3_VALID)) {
                        if (!alloc)
                                return NULL;

                        root = (void *)get_zeroed_page(GFP_ATOMIC);
                        if (root == NULL)
                                return NULL;

                        *pte = __pa(root) | GCR3_VALID;
                }

                root = __va(*pte & PAGE_MASK);

                level -= 1;
        }

        return pte;
}

static int __set_gcr3(struct protection_domain *domain, int pasid,
                      unsigned long cr3)
{
        u64 *pte;

        if (domain->mode != PAGE_MODE_NONE)
                return -EINVAL;

        pte = __get_gcr3_pte(domain->gcr3_tbl, domain->glx, pasid, true);
        if (pte == NULL)
                return -ENOMEM;

        *pte = (cr3 & PAGE_MASK) | GCR3_VALID;

        return __amd_iommu_flush_tlb(domain, pasid);
}

static int __clear_gcr3(struct protection_domain *domain, int pasid)
{
        u64 *pte;

        if (domain->mode != PAGE_MODE_NONE)
                return -EINVAL;

        pte = __get_gcr3_pte(domain->gcr3_tbl, domain->glx, pasid, false);
        if (pte == NULL)
                return 0;

        *pte = 0;

        return __amd_iommu_flush_tlb(domain, pasid);
}

int amd_iommu_domain_set_gcr3(struct iommu_domain *dom, int pasid,
                              unsigned long cr3)
{
        struct protection_domain *domain = dom->priv;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __set_gcr3(domain, pasid, cr3);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_domain_set_gcr3);

int amd_iommu_domain_clear_gcr3(struct iommu_domain *dom, int pasid)
{
        struct protection_domain *domain = dom->priv;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __clear_gcr3(domain, pasid);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_domain_clear_gcr3);

int amd_iommu_complete_ppr(struct pci_dev *pdev, int pasid,
                           int status, int tag)
{
        struct iommu_dev_data *dev_data;
        struct amd_iommu *iommu;
        struct iommu_cmd cmd;

        INC_STATS_COUNTER(complete_ppr);

        dev_data = get_dev_data(&pdev->dev);
        iommu    = amd_iommu_rlookup_table[dev_data->devid];

        build_complete_ppr(&cmd, dev_data->devid, pasid, status,
                           tag, dev_data->pri_tlp);

        return iommu_queue_command(iommu, &cmd);
}
EXPORT_SYMBOL(amd_iommu_complete_ppr);

struct iommu_domain *amd_iommu_get_v2_domain(struct pci_dev *pdev)
{
        struct protection_domain *domain;

        domain = get_domain(&pdev->dev);
        if (IS_ERR(domain))
                return NULL;

        /* Only return IOMMUv2 domains */
        if (!(domain->flags & PD_IOMMUV2_MASK))
                return NULL;

        return domain->iommu_domain;
}
EXPORT_SYMBOL(amd_iommu_get_v2_domain);

void amd_iommu_enable_device_erratum(struct pci_dev *pdev, u32 erratum)
{
        struct iommu_dev_data *dev_data;

        if (!amd_iommu_v2_supported())
                return;

        dev_data = get_dev_data(&pdev->dev);
        dev_data->errata |= (1 << erratum);
}
EXPORT_SYMBOL(amd_iommu_enable_device_erratum);

int amd_iommu_device_info(struct pci_dev *pdev,
                          struct amd_iommu_device_info *info)
{
        int max_pasids;
        int pos;

        if (pdev == NULL || info == NULL)
                return -EINVAL;

        if (!amd_iommu_v2_supported())
                return -EINVAL;

        memset(info, 0, sizeof(*info));

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS);
        if (pos)
                info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
        if (pos)
                info->flags |= AMD_IOMMU_DEVICE_FLAG_PRI_SUP;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
        if (pos) {
                int features;

                max_pasids = 1 << (9 * (amd_iommu_max_glx_val + 1));
                max_pasids = min(max_pasids, (1 << 20));

                info->flags |= AMD_IOMMU_DEVICE_FLAG_PASID_SUP;
                info->max_pasids = min(pci_max_pasids(pdev), max_pasids);

                features = pci_pasid_features(pdev);
                if (features & PCI_PASID_CAP_EXEC)
                        info->flags |= AMD_IOMMU_DEVICE_FLAG_EXEC_SUP;
                if (features & PCI_PASID_CAP_PRIV)
                        info->flags |= AMD_IOMMU_DEVICE_FLAG_PRIV_SUP;
        }

        return 0;
}
EXPORT_SYMBOL(amd_iommu_device_info);

#ifdef CONFIG_IRQ_REMAP

/*****************************************************************************
 *
 * Interrupt Remapping Implementation
 *
 *****************************************************************************/

union irte {
        u32 val;
        struct {
                u32 valid       : 1,
                    no_fault    : 1,
                    int_type    : 3,
                    rq_eoi      : 1,
                    dm          : 1,
                    rsvd_1      : 1,
                    destination : 8,
                    vector      : 8,
                    rsvd_2      : 8;
        } fields;
};

#define DTE_IRQ_PHYS_ADDR_MASK  (((1ULL << 45)-1) << 6)
#define DTE_IRQ_REMAP_INTCTL    (2ULL << 60)
#define DTE_IRQ_TABLE_LEN       (8ULL << 1)
#define DTE_IRQ_REMAP_ENABLE    1ULL

static void set_dte_irq_entry(u16 devid, struct irq_remap_table *table)
{
        u64 dte;

        dte     = amd_iommu_dev_table[devid].data[2];
        dte     &= ~DTE_IRQ_PHYS_ADDR_MASK;
        dte     |= virt_to_phys(table->table);
        dte     |= DTE_IRQ_REMAP_INTCTL;
        dte     |= DTE_IRQ_TABLE_LEN;
        dte     |= DTE_IRQ_REMAP_ENABLE;

        amd_iommu_dev_table[devid].data[2] = dte;
}

#define IRTE_ALLOCATED (~1U)

static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic)
{
        struct irq_remap_table *table = NULL;
        struct amd_iommu *iommu;
        unsigned long flags;
        u16 alias;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);

        iommu = amd_iommu_rlookup_table[devid];
        if (!iommu)
                goto out_unlock;

        table = irq_lookup_table[devid];
        if (table)
                goto out;

        alias = amd_iommu_alias_table[devid];
        table = irq_lookup_table[alias];
        if (table) {
                irq_lookup_table[devid] = table;
                set_dte_irq_entry(devid, table);
                iommu_flush_dte(iommu, devid);
                goto out;
        }

        /* Nothing there yet, allocate new irq remapping table */
        table = kzalloc(sizeof(*table), GFP_ATOMIC);
        if (!table)
                goto out;

        /* Initialize table spin-lock */
        spin_lock_init(&table->lock);

        if (ioapic)
                /* Keep the first 32 indexes free for IOAPIC interrupts */
                table->min_index = 32;

        table->table = kmem_cache_alloc(amd_iommu_irq_cache, GFP_ATOMIC);
        if (!table->table) {
                kfree(table);
                table = NULL;
                goto out;
        }

        memset(table->table, 0, MAX_IRQS_PER_TABLE * sizeof(u32));

        if (ioapic) {
                int i;

                for (i = 0; i < 32; ++i)
                        table->table[i] = IRTE_ALLOCATED;
        }

        irq_lookup_table[devid] = table;
        set_dte_irq_entry(devid, table);
        iommu_flush_dte(iommu, devid);
        if (devid != alias) {
                irq_lookup_table[alias] = table;
                set_dte_irq_entry(devid, table);
                iommu_flush_dte(iommu, alias);
        }

out:
        iommu_completion_wait(iommu);

out_unlock:
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        return table;
}

static int alloc_irq_index(struct irq_cfg *cfg, u16 devid, int count)
{
        struct irq_remap_table *table;
        unsigned long flags;
        int index, c;

        table = get_irq_table(devid, false);
        if (!table)
                return -ENODEV;

        spin_lock_irqsave(&table->lock, flags);

        /* Scan table for free entries */
        for (c = 0, index = table->min_index;
             index < MAX_IRQS_PER_TABLE;
             ++index) {
                if (table->table[index] == 0)
                        c += 1;
                else
                        c = 0;

                if (c == count) {
                        struct irq_2_irte *irte_info;

                        for (; c != 0; --c)
                                table->table[index - c + 1] = IRTE_ALLOCATED;

                        index -= count - 1;

                        cfg->remapped         = 1;