linux-next/drivers/iommu/amd_iommu.c

/*
 * Copyright (C) 2007-2010 Advanced Micro Devices, Inc.
 * Author: Joerg Roedel <jroedel@suse.de>
 *         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 <linux/dma-contiguous.h>
#include <linux/irqdomain.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"

#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);

/* 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 const 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;

/*
 * This struct contains device specific data for the IOMMU
 */
struct iommu_dev_data {
	struct list_head list;		  /* For domain->dev_list */
	struct list_head dev_data_list;	  /* For global dev_data_list */
	struct protection_domain *domain; /* Domain the device is bound to */
	u16 devid;			  /* PCI Device ID */
	bool iommu_v2;			  /* Device can make use of IOMMUv2 */
	bool passthrough;		  /* Device is identity mapped */
	struct {
		bool enabled;
		int qdep;
	} ats;				  /* ATS state */
	bool pri_tlp;			  /* PASID TLB required for
					     PPR completions */
	u32 errata;			  /* Bitmap for errata to apply */
};

/*
 * 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 protection_domain_init(struct protection_domain *domain);

/*
 * For dynamic growth the aperture size is split into ranges of 128MB of
 * DMA address space each. This struct represents one such range.
 */
struct aperture_range {

	spinlock_t bitmap_lock;

	/* address allocation bitmap */
	unsigned long *bitmap;

	/*
	 * Array of PTE pages for the aperture. In this array we save all the
	 * leaf pages of the domain page table used for the aperture. This way
	 * we don't need to walk the page table to find a specific PTE. We can
	 * just calculate its address in constant time.
	 */
	u64 *pte_pages[64];

	unsigned long offset;
};

/*
 * Data container for a dma_ops specific protection domain
 */
struct dma_ops_domain {
	/* generic protection domain information */
	struct protection_domain domain;

	/* size of the aperture for the mappings */
	unsigned long aperture_size;

	/* address we start to search for free addresses */
	unsigned long next_address;

	/* address space relevant data */
	struct aperture_range *aperture[APERTURE_MAX_RANGES];

	/* This will be set to true when TLB needs to be flushed */
	bool need_flush;
};

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

static struct protection_domain *to_pdomain(struct iommu_domain *dom)
{
	return container_of(dom, struct protection_domain, domain);
}

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;

	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 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;
}

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

	for (addr = e->address_start; addr < e->address_end;
	     addr += PAGE_SIZE) {
		if (addr < dma_dom->aperture_size)
			__set_bit(addr >> PAGE_SHIFT,
				  dma_dom->aperture[0]->bitmap);
	}
}

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

	devid = get_device_id(dev);

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

/*
 * 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 PCI device */
	if (!dev_is_pci(dev))
		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 void init_iommu_group(struct device *dev)
{
	struct dma_ops_domain *dma_domain;
	struct iommu_domain *domain;
	struct iommu_group *group;

	group = iommu_group_get_for_dev(dev);
	if (IS_ERR(group))
		return;

	domain = iommu_group_default_domain(group);
	if (!domain)
		goto out;

	dma_domain = to_pdomain(domain)->priv;

	init_unity_mappings_for_device(dev, dma_domain);
out:
	iommu_group_put(group);
}

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

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

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

	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;

	iommu_device_link(amd_iommu_rlookup_table[dev_data->devid]->iommu_dev,
			  dev);

	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)
{
	struct iommu_dev_data *dev_data = search_dev_data(get_device_id(dev));

	if (!dev_data)
		return;

	iommu_device_unlink(amd_iommu_rlookup_table[dev_data->devid]->iommu_dev,
			    dev);

	iommu_group_remove_device(dev);

	/* Remove dma-ops */
	dev->archdata.dma_ops = NULL;

	/*
	 * 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.
	 */
}

#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) % EVT_BUFFER_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)) % CMD_BUFFER_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;
	bool s;

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

	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 = true;
	}

	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;
	bool s;

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

	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 = true;
	}

	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;
	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 >> 8) & 0xff) << 16;
	cmd->data[0] |= (qdep  & 0xff) << 24;
	cmd->data[1]  = devid;
	cmd->data[1] |= (pasid & 0xff) << 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;
		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;

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)) % CMD_BUFFER_SIZE;
	left      = (head - next_tail) % CMD_BUFFER_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;
	u16 alias;
	int ret;

	iommu = amd_iommu_rlookup_table[dev_data->devid];
	alias = amd_iommu_alias_table[dev_data->devid];

	ret = iommu_flush_dte(iommu, dev_data->devid);
	if (!ret && alias != dev_data->devid)
		ret = iommu_flush_dte(iommu, alias);
	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,
		      unsigned long *page_size)
{
	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)];
	*page_size =  PTE_LEVEL_PAGE_SIZE(level);

	while (level > 0) {

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

		/* Large PTE */
		if (PM_PTE_LEVEL(*pte) == 7 ||
		    PM_PTE_LEVEL(*pte) == 0)
			break;

		/* 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)];
		*page_size = PTE_LEVEL_PAGE_SIZE(level);
	}

	if (PM_PTE_LEVEL(*pte) == 0x07) {
		unsigned long pte_mask;

		/*
		 * If we have a series of large PTEs, make
		 * sure to return a pointer to the first one.
		 */
		*page_size = pte_mask = PTE_PAGE_SIZE(*pte);
		pte_mask   = ~((PAGE_SIZE_PTE_COUNT(pte_mask) << 3) - 1);
		pte        = (u64 *)(((unsigned long)pte) & pte_mask);
	}

	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;

	BUG_ON(!IS_ALIGNED(bus_addr, page_size));
	BUG_ON(!IS_ALIGNED(phys_addr, page_size));

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

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

	if (!pte)
		return -ENOMEM;

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

	if (count > 1) {
		__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 unmapped;
	unsigned long unmap_size;
	u64 *pte;

	BUG_ON(!is_power_of_2(page_size));

	unmapped = 0;

	while (unmapped < page_size) {

		pte = fetch_pte(dom, bus_addr, &unmap_size);

		if (pte) {
			int i, count;

			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(unmapped && !is_power_of_2(unmapped));

	return unmapped;
}

/****************************************************************************
 *
 * 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, pte_pgsize;

#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;

	spin_lock_init(&dma_dom->aperture[index]->bitmap_lock);

	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 += pte_pgsize) {
		u64 *pte = fetch_pte(&dma_dom->domain, i, &pte_pgsize);
		if (!pte || !IOMMU_PTE_PRESENT(*pte))
			continue;

		dma_ops_reserve_addresses(dma_dom, i >> PAGE_SHIFT,
					  pte_pgsize >> 12);
	}

	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, mask;
	unsigned long address = -1;
	unsigned long limit;
	unsigned long flags;

	next_bit >>= PAGE_SHIFT;

	mask = dma_get_seg_boundary(dev);

	boundary_size = mask + 1 ? ALIGN(mask + 1, PAGE_SIZE) >> PAGE_SHIFT :
				   1UL << (BITS_PER_LONG - 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);

		spin_lock_irqsave(&dom->aperture[i]->bitmap_lock, flags);
		address = iommu_area_alloc(dom->aperture[i]->bitmap,
					   limit, next_bit, pages, offset,
					    boundary_size, align_mask);
		spin_unlock_irqrestore(&dom->aperture[i]->bitmap_lock, flags);
		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];
	unsigned long flags;

	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;

	spin_lock_irqsave(&range->bitmap_lock, flags);
	bitmap_clear(range->bitmap, address, pages);
	spin_unlock_irqrestore(&range->bitmap_lock, flags);

}

/****************************************************************************
 *
 * 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);
}

#define DEFINE_FREE_PT_FN(LVL, FN)				\
static void free_pt_##LVL (unsigned long __pt)			\
{								\
	unsigned long p;					\
	u64 *pt;						\
	int i;							\
								\
	pt = (u64 *)__pt;					\
								\
	for (i = 0; i < 512; ++i) {				\
		/* PTE present? */				\
		if (!IOMMU_PTE_PRESENT(pt[i]))			\
			continue;				\
								\
		/* Large PTE? */				\
		if (PM_PTE_LEVEL(pt[i]) == 0 ||			\
		    PM_PTE_LEVEL(pt[i]) == 7)			\
			continue;				\
								\
		p = (unsigned long)IOMMU_PTE_PAGE(pt[i]);	\
		FN(p);						\
	}							\
	free_page((unsigned long)pt);				\
}

DEFINE_FREE_PT_FN(l2, free_page)
DEFINE_FREE_PT_FN(l3, free_pt_l2)
DEFINE_FREE_PT_FN(l4, free_pt_l3)
DEFINE_FREE_PT_FN(l5, free_pt_l4)
DEFINE_FREE_PT_FN(l6, free_pt_l5)

static void free_pagetable(struct protection_domain *domain)
{
	unsigned long root = (unsigned long)domain->pt_root;

	switch (domain->mode) {
	case PAGE_MODE_NONE:
		break;
	case PAGE_MODE_1_LEVEL:
		free_page(root);
		break;
	case PAGE_MODE_2_LEVEL:
		free_pt_l2(root);
		break;
	case PAGE_MODE_3_LEVEL:
		free_pt_l3(root);
		break;
	case PAGE_MODE_4_LEVEL:
		free_pt_l4(root);
		break;
	case PAGE_MODE_5_LEVEL:
		free_pt_l5(root);
		break;
	case PAGE_MODE_6_LEVEL:
		free_pt_l6(root);
		break;
	default:
		BUG();
	}
}

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
		BUG_ON(domain->glx != 0);

	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;

	if (protection_domain_init(&dma_dom->domain))
		goto free_dma_dom;

	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;

	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] &= DTE_FLAG_MASK;

	amd_iommu_apply_erratum_63(devid);
}

static void do_attach(struct iommu_dev_data *dev_data,
		      struct protection_domain *domain)
{
	struct amd_iommu *iommu;
	u16 alias;
	bool ats;

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

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

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

	/* Update device table */
	set_dte_entry(dev_data->devid, domain, ats);
	if (alias != dev_data->devid)
		set_dte_entry(dev_data->devid, domain, ats);

	device_flush_dte(dev_data);
}

static void do_detach(struct iommu_dev_data *dev_data)
{
	struct amd_iommu *iommu;
	u16 alias;

	/*
	 * First check if the device is still attached. It might already
	 * be detached from its domain because the generic
	 * iommu_detach_group code detached it and we try again here in
	 * our alias handling.
	 */
	if (!dev_data->domain)
		return;

	iommu = amd_iommu_rlookup_table[dev_data->devid];
	alias = amd_iommu_alias_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);
	if (alias != dev_data->devid)
		clear_dte_entry(alias);

	/* 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;

	/*
	 * Must be called with IRQs disabled. Warn here to detect early
	 * when its not.
	 */
	WARN_ON(!irqs_disabled());

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

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

	/* Attach alias group root */
	do_attach(dev_data, domain);

	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->passthrough)
			return -EINVAL;

		if (dev_data->iommu_v2) {
			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;

	/*
	 * Must be called with IRQs disabled. Warn here to detect early
	 * when its not.
	 */
	WARN_ON(!irqs_disabled());

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

	domain = dev_data->domain;

	spin_lock(&domain->lock);

	do_detach(dev_data);

	spin_unlock(&domain->lock);
}

/*
 * 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 && dev_data->iommu_v2)
		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;
}

static int amd_iommu_add_device(struct device *dev)
{
	struct iommu_dev_data *dev_data;
	struct iommu_domain *domain;
	struct amd_iommu *iommu;
	u16 devid;
	int ret;

	if (!check_device(dev) || get_dev_data(dev))
		return 0;

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

	ret = iommu_init_device(dev);
	if (ret) {
		if (ret != -ENOTSUPP)
			pr_err("Failed to initialize device %s - trying to proceed anyway\n",
				dev_name(dev));

		iommu_ignore_device(dev);
		dev->archdata.dma_ops = &nommu_dma_ops;
		goto out;
	}
	init_iommu_group(dev);

	dev_data = get_dev_data(dev);

	BUG_ON(!dev_data);

	if (iommu_pass_through || dev_data->iommu_v2)
		iommu_request_dm_for_dev(dev);

	/* Domains are initialized for this device - have a look what we ended up with */
	domain = iommu_get_domain_for_dev(dev);
	if (domain->type == IOMMU_DOMAIN_IDENTITY)
		dev_data->passthrough = true;
	else
		dev->archdata.dma_ops = &amd_iommu_dma_ops;

out:
	iommu_completion_wait(iommu);

	return 0;
}

static void amd_iommu_remove_device(struct device *dev)
{
	struct amd_iommu *iommu;
	u16 devid;

	if (!check_device(dev))
		return;

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

	iommu_uninit_device(dev);
	iommu_completion_wait(iommu);
}

/*****************************************************************************
 *
 * 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 iommu_domain *io_domain;

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

	io_domain = iommu_get_domain_for_dev(dev);
	if (!io_domain)
		return NULL;

	domain = to_pdomain(io_domain);
	if (!dma_ops_domain(domain))
		return ERR_PTR(-EBUSY);

	return 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_ONCE(*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_ONCE(!*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);
	}

	domain_flush_pages(&dma_dom->domain, address, size);

	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;
	}

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

	SUB_STATS_COUNTER(alloced_io_mem, size);

	dma_ops_free_addresses(dma_dom, dma_addr, pages);
}

/*
 * 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)
{
	u64 dma_mask = dev->coherent_dma_mask;
	struct protection_domain *domain;
	unsigned long flags;
	struct page *page;

	INC_STATS_COUNTER(cnt_alloc_coherent);

	domain = get_domain(dev);
	if (PTR_ERR(domain) == -EINVAL) {
		page = alloc_pages(flag, get_order(size));
		*dma_addr = page_to_phys(page);
		return page_address(page);
	} else if (IS_ERR(domain))
		return NULL;

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

	page = alloc_pages(flag | __GFP_NOWARN,  get_order(size));
	if (!page) {
		if (!gfpflags_allow_blocking(flag))
			return NULL;

		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
						 get_order(size));
		if (!page)
			return NULL;
	}

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

	spin_lock_irqsave(&domain->lock, flags);

	*dma_addr = __map_single(dev, domain->priv, page_to_phys(page),
				 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 page_address(page);

out_free:

	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
		__free_pages(page, 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)
{
	struct protection_domain *domain;
	unsigned long flags;
	struct page *page;

	INC_STATS_COUNTER(cnt_free_coherent);

	page = virt_to_page(virt_addr);
	size = PAGE_ALIGN(size);

	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:
	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
		__free_pages(page, 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);
}

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,
};

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

int __init amd_iommu_init_dma_ops(void)
{
	swiotlb        = iommu_pass_through ? 1 : 0;
	iommu_detected = 1;

	/*
	 * In case we don't initialize SWIOTLB (actually the common case
	 * when AMD IOMMU is enabled), make sure there are global
	 * dma_ops set as a fall-back for devices not handled by this
	 * driver (for example non-PCI devices).
	 */
	if (!swiotlb)
		dma_ops = &nommu_dma_ops;

	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;
}

/*****************************************************************************
 *
 * 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 *entry;
	unsigned long flags;

	write_lock_irqsave(&amd_iommu_devtable_lock, flags);

	while (!list_empty(&domain->dev_list)) {
		entry = list_first_entry(&domain->dev_list,
					 struct iommu_dev_data, list);
		__detach_device(entry);
	}

	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 int protection_domain_init(struct protection_domain *domain)
{
	spin_lock_init(&domain->lock);
	mutex_init(&domain->api_lock);
	domain->id = domain_id_alloc();
	if (!domain->id)
		return -ENOMEM;
	INIT_LIST_HEAD(&domain->dev_list);

	return 0;
}

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

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

	if (protection_domain_init(domain))
		goto out_err;

	add_domain_to_list(domain);

	return domain;

out_err:
	kfree(domain);

	return NULL;
}

static struct iommu_domain *amd_iommu_domain_alloc(unsigned type)
{
	struct protection_domain *pdomain;
	struct dma_ops_domain *dma_domain;

	switch (type) {
	case IOMMU_DOMAIN_UNMANAGED:
		pdomain = protection_domain_alloc();
		if (!pdomain)
			return NULL;

		pdomain->mode    = PAGE_MODE_3_LEVEL;
		pdomain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
		if (!pdomain->pt_root) {
			protection_domain_free(pdomain);
			return NULL;
		}

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

		break;
	case IOMMU_DOMAIN_DMA:
		dma_domain = dma_ops_domain_alloc();
		if (!dma_domain) {
			pr_err("AMD-Vi: Failed to allocate\n");
			return NULL;
		}
		pdomain = &dma_domain->domain;
		break;
	case IOMMU_DOMAIN_IDENTITY:
		pdomain = protection_domain_alloc();
		if (!pdomain)
			return NULL;

		pdomain->mode = PAGE_MODE_NONE;
		break;
	default:
		return NULL;
	}

	return &pdomain->domain;
}

static void amd_iommu_domain_free(struct iommu_domain *dom)
{
	struct protection_domain *domain;

	if (!dom)
		return;

	domain = to_pdomain(dom);

	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);
}

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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	unsigned long offset_mask, pte_pgsize;
	u64 *pte, __pte;

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

	pte = fetch_pte(domain, iova, &pte_pgsize);

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

	offset_mask = pte_pgsize - 1;
	__pte	    = *pte & PM_ADDR_MASK;

	return (__pte & ~offset_mask) | (iova & offset_mask);
}

static bool amd_iommu_capable(enum iommu_cap cap)
{
	switch (cap) {
	case IOMMU_CAP_CACHE_COHERENCY:
		return true;
	case IOMMU_CAP_INTR_REMAP:
		return (irq_remapping_enabled == 1);
	case IOMMU_CAP_NOEXEC:
		return false;
	}

	return false;
}

static void amd_iommu_get_dm_regions(struct device *dev,
				     struct list_head *head)
{
	struct unity_map_entry *entry;
	u16 devid;

	devid = get_device_id(dev);

	list_for_each_entry(entry, &amd_iommu_unity_map, list) {
		struct iommu_dm_region *region;

		if (devid < entry->devid_start || devid > entry->devid_end)
			continue;

		region = kzalloc(sizeof(*region), GFP_KERNEL);
		if (!region) {
			pr_err("Out of memory allocating dm-regions for %s\n",
				dev_name(dev));
			return;
		}

		region->start = entry->address_start;
		region->length = entry->address_end - entry->address_start;
		if (entry->prot & IOMMU_PROT_IR)
			region->prot |= IOMMU_READ;
		if (entry->prot & IOMMU_PROT_IW)
			region->prot |= IOMMU_WRITE;

		list_add_tail(&region->list, head);
	}
}

static void amd_iommu_put_dm_regions(struct device *dev,
				     struct list_head *head)
{
	struct iommu_dm_region *entry, *next;

	list_for_each_entry_safe(entry, next, head, list)
		kfree(entry);
}

static const struct iommu_ops amd_iommu_ops = {
	.capable = amd_iommu_capable,
	.domain_alloc = amd_iommu_domain_alloc,
	.domain_free  = amd_iommu_domain_free,
	.attach_dev = amd_iommu_attach_device,
	.detach_dev = amd_iommu_detach_device,
	.map = amd_iommu_map,
	.unmap = amd_iommu_unmap,
	.map_sg = default_iommu_map_sg,
	.iova_to_phys = amd_iommu_iova_to_phys,
	.add_device = amd_iommu_add_device,
	.remove_device = amd_iommu_remove_device,
	.device_group = pci_device_group,
	.get_dm_regions = amd_iommu_get_dm_regions,
	.put_dm_regions = amd_iommu_put_dm_regions,
	.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.
 *
 *****************************************************************************/

/* 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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	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;

		/*
		   There might be non-IOMMUv2 capable devices in an IOMMUv2
		 * domain.
		 */
		if (!dev_data->ats.enabled)
			continue;

		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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	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 = to_pdomain(dom);
	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 *pdomain;

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

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

	return &pdomain->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;
};

struct irq_2_irte {
	u16 devid; /* Device ID for IRTE table */
	u16 index; /* Index into IRTE table*/
};

struct amd_ir_data {
	struct irq_2_irte			irq_2_irte;
	union irte				irte_entry;
	union {
		struct msi_msg			msi_entry;
	};
};

static struct irq_chip amd_ir_chip;

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

			index -= count - 1;
			goto out;
		}
	}

	index = -ENOSPC;

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

	return index;
}

static int modify_irte(u16 devid, int index, union irte irte)
{
	struct irq_remap_table *table;
	struct amd_iommu *iommu;
	unsigned long flags;

	iommu = amd_iommu_rlookup_table[devid];
	if (iommu == NULL)
		return -EINVAL;

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

	spin_lock_irqsave(&table->lock, flags);
	table->table[index] = irte.val;
	spin_unlock_irqrestore(&table->lock, flags);

	iommu_flush_irt(iommu, devid);
	iommu_completion_wait(iommu);

	return 0;
}

static void free_irte(u16 devid, int index)
{
	struct irq_remap_table *table;
	struct amd_iommu *iommu;
	unsigned long flags;

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

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

	spin_lock_irqsave(&table->lock, flags);
	table->table[index] = 0;
	spin_unlock_irqrestore(&table->lock, flags);

	iommu_flush_irt(iommu, devid);
	iommu_completion_wait(iommu);
}

static int get_devid(struct irq_alloc_info *info)
{
	int devid = -1;

	switch (info->type) {
	case X86_IRQ_ALLOC_TYPE_IOAPIC:
		devid     = get_ioapic_devid(info->ioapic_id);
		break;
	case X86_IRQ_ALLOC_TYPE_HPET:
		devid     = get_hpet_devid(info->hpet_id);
		break;
	case X86_IRQ_ALLOC_TYPE_MSI:
	case X86_IRQ_ALLOC_TYPE_MSIX:
		devid = get_device_id(&info->msi_dev->dev);
		break;
	default:
		BUG_ON(1);
		break;
	}

	return devid;
}

static struct irq_domain *get_ir_irq_domain(struct irq_alloc_info *info)
{
	struct amd_iommu *iommu;
	int devid;

	if (!info)
		return NULL;

	devid = get_devid(info);
	if (devid >= 0) {
		iommu = amd_iommu_rlookup_table[devid];
		if (iommu)
			return iommu->ir_domain;
	}

	return NULL;
}

static struct irq_domain *get_irq_domain(struct irq_alloc_info *info)
{
	struct amd_iommu *iommu;
	int devid;

	if (!info)
		return NULL;

	switch (info->type) {
	case X86_IRQ_ALLOC_TYPE_MSI:
	case X86_IRQ_ALLOC_TYPE_MSIX:
		devid = get_device_id(&info->msi_dev->dev);
		if (devid >= 0) {
			iommu = amd_iommu_rlookup_table[devid];
			if (iommu)
				return iommu->msi_domain;
		}
		break;
	default:
		break;
	}

	return NULL;
}

struct irq_remap_ops amd_iommu_irq_ops = {
	.prepare		= amd_iommu_prepare,
	.enable			= amd_iommu_enable,
	.disable		= amd_iommu_disable,
	.reenable		= amd_iommu_reenable,
	.enable_faulting	= amd_iommu_enable_faulting,
	.get_ir_irq_domain	= get_ir_irq_domain,
	.get_irq_domain		= get_irq_domain,
};

static void irq_remapping_prepare_irte(struct amd_ir_data *data,
				       struct irq_cfg *irq_cfg,
				       struct irq_alloc_info *info,
				       int devid, int index, int sub_handle)
{
	struct irq_2_irte *irte_info = &data->irq_2_irte;
	struct msi_msg *msg = &data->msi_entry;
	union irte *irte = &data->irte_entry;
	struct IO_APIC_route_entry *entry;

	data->irq_2_irte.devid = devid;
	data->irq_2_irte.index = index + sub_handle;

	/* Setup IRTE for IOMMU */
	irte->val = 0;
	irte->fields.vector      = irq_cfg->vector;
	irte->fields.int_type    = apic->irq_delivery_mode;
	irte->fields.destination = irq_cfg->dest_apicid;
	irte->fields.dm          = apic->irq_dest_mode;
	irte->fields.valid       = 1;

	switch (info->type) {
	case X86_IRQ_ALLOC_TYPE_IOAPIC:
		/* Setup IOAPIC entry */
		entry = info->ioapic_entry;
		info->ioapic_entry = NULL;
		memset(entry, 0, sizeof(*entry));
		entry->vector        = index;
		entry->mask          = 0;
		entry->trigger       = info->ioapic_trigger;
		entry->polarity      = info->ioapic_polarity;
		/* Mask level triggered irqs. */
		if (info->ioapic_trigger)
			entry->mask = 1;
		break;

	case X86_IRQ_ALLOC_TYPE_HPET:
	case X86_IRQ_ALLOC_TYPE_MSI:
	case X86_IRQ_ALLOC_TYPE_MSIX:
		msg->address_hi = MSI_ADDR_BASE_HI;
		msg->address_lo = MSI_ADDR_BASE_LO;
		msg->data = irte_info->index;
		break;

	default:
		BUG_ON(1);
		break;
	}
}

static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
			       unsigned int nr_irqs, void *arg)
{
	struct irq_alloc_info *info = arg;
	struct irq_data *irq_data;
	struct amd_ir_data *data;
	struct irq_cfg *cfg;
	int i, ret, devid;
	int index = -1;

	if (!info)
		return -EINVAL;
	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_MSI &&
	    info->type != X86_IRQ_ALLOC_TYPE_MSIX)
		return -EINVAL;

	/*
	 * With IRQ remapping enabled, don't need contiguous CPU vectors
	 * to support multiple MSI interrupts.
	 */
	if (info->type == X86_IRQ_ALLOC_TYPE_MSI)
		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;

	devid = get_devid(info);
	if (devid < 0)
		return -EINVAL;

	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
	if (ret < 0)
		return ret;

	if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC) {
		if (get_irq_table(devid, true))
			index = info->ioapic_pin;
		else
			ret = -ENOMEM;
	} else {
		index = alloc_irq_index(devid, nr_irqs);
	}
	if (index < 0) {
		pr_warn("Failed to allocate IRTE\n");
		goto out_free_parent;
	}

	for (i = 0; i < nr_irqs; i++) {
		irq_data = irq_domain_get_irq_data(domain, virq + i);
		cfg = irqd_cfg(irq_data);
		if (!irq_data || !cfg) {
			ret = -EINVAL;
			goto out_free_data;
		}

		ret = -ENOMEM;
		data = kzalloc(sizeof(*data), GFP_KERNEL);
		if (!data)
			goto out_free_data;

		irq_data->hwirq = (devid << 16) + i;
		irq_data->chip_data = data;
		irq_data->chip = &amd_ir_chip;
		irq_remapping_prepare_irte(data, cfg, info, devid, index, i);
		irq_set_status_flags(virq + i, IRQ_MOVE_PCNTXT);
	}

	return 0;

out_free_data:
	for (i--; i >= 0; i--) {
		irq_data = irq_domain_get_irq_data(domain, virq + i);
		if (irq_data)
			kfree(irq_data->chip_data);
	}
	for (i = 0; i < nr_irqs; i++)
		free_irte(devid, index + i);
out_free_parent:
	irq_domain_free_irqs_common(domain, virq, nr_irqs);
	return ret;
}

static void irq_remapping_free(struct irq_domain *domain, unsigned int virq,
			       unsigned int nr_irqs)
{
	struct irq_2_irte *irte_info;
	struct irq_data *irq_data;
	struct amd_ir_data *data;
	int i;

	for (i = 0; i < nr_irqs; i++) {
		irq_data = irq_domain_get_irq_data(domain, virq  + i);
		if (irq_data && irq_data->chip_data) {
			data = irq_data->chip_data;
			irte_info = &data->irq_2_irte;
			free_irte(irte_info->devid, irte_info->index);
			kfree(data);
		}
	}
	irq_domain_free_irqs_common(domain, virq, nr_irqs);
}

static void irq_remapping_activate(struct irq_domain *domain,
				   struct irq_data *irq_data)
{
	struct amd_ir_data *data = irq_data->chip_data;
	struct irq_2_irte *irte_info = &data->irq_2_irte;

	modify_irte(irte_info->devid, irte_info->index, data->irte_entry);
}

static void irq_remapping_deactivate(struct irq_domain *domain,
				     struct irq_data *irq_data)
{
	struct amd_ir_data *data = irq_data->chip_data;
	struct irq_2_irte *irte_info = &data->irq_2_irte;
	union irte entry;

	entry.val = 0;
	modify_irte(irte_info->devid, irte_info->index, data->irte_entry);
}

static struct irq_domain_ops amd_ir_domain_ops = {
	.alloc = irq_remapping_alloc,
	.free = irq_remapping_free,
	.activate = irq_remapping_activate,
	.deactivate = irq_remapping_deactivate,
};

static int amd_ir_set_affinity(struct irq_data *data,
			       const struct cpumask *mask, bool force)
{
	struct amd_ir_data *ir_data = data->chip_data;
	struct irq_2_irte *irte_info = &ir_data->irq_2_irte;
	struct irq_cfg *cfg = irqd_cfg(data);
	struct irq_data *parent = data->parent_data;
	int ret;

	ret = parent->chip->irq_set_affinity(parent, mask, force);
	if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
		return ret;

	/*
	 * Atomically updates the IRTE with the new destination, vector
	 * and flushes the interrupt entry cache.
	 */
	ir_data->irte_entry.fields.vector = cfg->vector;
	ir_data->irte_entry.fields.destination = cfg->dest_apicid;
	modify_irte(irte_info->devid, irte_info->index, ir_data->irte_entry);

	/*
	 * After this point, all the interrupts will start arriving
	 * at the new destination. So, time to cleanup the previous
	 * vector allocation.
	 */
	send_cleanup_vector(cfg);

	return IRQ_SET_MASK_OK_DONE;
}

static void ir_compose_msi_msg(struct irq_data *irq_data, struct msi_msg *msg)
{
	struct amd_ir_data *ir_data = irq_data->chip_data;

	*msg = ir_data->msi_entry;
}

static struct irq_chip amd_ir_chip = {
	.irq_ack = ir_ack_apic_edge,
	.irq_set_affinity = amd_ir_set_affinity,
	.irq_compose_msi_msg = ir_compose_msi_msg,
};

int amd_iommu_create_irq_domain(struct amd_iommu *iommu)
{
	iommu->ir_domain = irq_domain_add_tree(NULL, &amd_ir_domain_ops, iommu);
	if (!iommu->ir_domain)
		return -ENOMEM;

	iommu->ir_domain->parent = arch_get_ir_parent_domain();
	iommu->msi_domain = arch_create_msi_irq_domain(iommu->ir_domain);

	return 0;
}
#endif