/*
 * Copyright (c) 2006, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 * Copyright (C) Ashok Raj <ashok.raj@intel.com>
 * Copyright (C) Shaohua Li <shaohua.li@intel.com>
 * Copyright (C) Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 */

#include <linux/init.h>
#include <linux/bitmap.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/sysdev.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/dmar.h>
#include <linux/dma-mapping.h>
#include <linux/mempool.h>
#include "iova.h"
#include "intel-iommu.h"
#include <asm/proto.h> /* force_iommu in this header in x86-64*/
#include <asm/cacheflush.h>
#include <asm/iommu.h>
#include "pci.h"

#define IS_GFX_DEVICE(pdev) ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY)
#define IS_ISA_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA)

#define IOAPIC_RANGE_START	(0xfee00000)
#define IOAPIC_RANGE_END	(0xfeefffff)
#define IOVA_START_ADDR		(0x1000)

#define DEFAULT_DOMAIN_ADDRESS_WIDTH 48

#define DMAR_OPERATION_TIMEOUT (HZ*60) /* 1m */

#define DOMAIN_MAX_ADDR(gaw) ((((u64)1) << gaw) - 1)

static void domain_remove_dev_info(struct dmar_domain *domain);

static int dmar_disabled;
static int __initdata dmar_map_gfx = 1;

#define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1))
static DEFINE_SPINLOCK(device_domain_lock);
static LIST_HEAD(device_domain_list);

static int __init intel_iommu_setup(char *str)
{
	if (!str)
		return -EINVAL;
	while (*str) {
		if (!strncmp(str, "off", 3)) {
			dmar_disabled = 1;
			printk(KERN_INFO"Intel-IOMMU: disabled\n");
		} else if (!strncmp(str, "igfx_off", 8)) {
			dmar_map_gfx = 0;
			printk(KERN_INFO
				"Intel-IOMMU: disable GFX device mapping\n");
		}

		str += strcspn(str, ",");
		while (*str == ',')
			str++;
	}
	return 0;
}
__setup("intel_iommu=", intel_iommu_setup);

static struct kmem_cache *iommu_domain_cache;
static struct kmem_cache *iommu_devinfo_cache;
static struct kmem_cache *iommu_iova_cache;

static inline void *alloc_pgtable_page(void)
{
	return (void *)get_zeroed_page(GFP_ATOMIC);
}

static inline void free_pgtable_page(void *vaddr)
{
	free_page((unsigned long)vaddr);
}

static inline void *alloc_domain_mem(void)
{
	return kmem_cache_alloc(iommu_domain_cache, GFP_ATOMIC);
}

static inline void free_domain_mem(void *vaddr)
{
	kmem_cache_free(iommu_domain_cache, vaddr);
}

static inline void * alloc_devinfo_mem(void)
{
	return kmem_cache_alloc(iommu_devinfo_cache, GFP_ATOMIC);
}

static inline void free_devinfo_mem(void *vaddr)
{
	kmem_cache_free(iommu_devinfo_cache, vaddr);
}

struct iova *alloc_iova_mem(void)
{
	return kmem_cache_alloc(iommu_iova_cache, GFP_ATOMIC);
}

void free_iova_mem(struct iova *iova)
{
	kmem_cache_free(iommu_iova_cache, iova);
}

static inline void __iommu_flush_cache(
	struct intel_iommu *iommu, void *addr, int size)
{
	if (!ecap_coherent(iommu->ecap))
		clflush_cache_range(addr, size);
}

/* Gets context entry for a given bus and devfn */
static struct context_entry * device_to_context_entry(struct intel_iommu *iommu,
		u8 bus, u8 devfn)
{
	struct root_entry *root;
	struct context_entry *context;
	unsigned long phy_addr;
	unsigned long flags;

	spin_lock_irqsave(&iommu->lock, flags);
	root = &iommu->root_entry[bus];
	context = get_context_addr_from_root(root);
	if (!context) {
		context = (struct context_entry *)alloc_pgtable_page();
		if (!context) {
			spin_unlock_irqrestore(&iommu->lock, flags);
			return NULL;
		}
		__iommu_flush_cache(iommu, (void *)context, PAGE_SIZE_4K);
		phy_addr = virt_to_phys((void *)context);
		set_root_value(root, phy_addr);
		set_root_present(root);
		__iommu_flush_cache(iommu, root, sizeof(*root));
	}
	spin_unlock_irqrestore(&iommu->lock, flags);
	return &context[devfn];
}

static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
{
	struct root_entry *root;
	struct context_entry *context;
	int ret;
	unsigned long flags;

	spin_lock_irqsave(&iommu->lock, flags);
	root = &iommu->root_entry[bus];
	context = get_context_addr_from_root(root);
	if (!context) {
		ret = 0;
		goto out;
	}
	ret = context_present(context[devfn]);
out:
	spin_unlock_irqrestore(&iommu->lock, flags);
	return ret;
}

static void clear_context_table(struct intel_iommu *iommu, u8 bus, u8 devfn)
{
	struct root_entry *root;
	struct context_entry *context;
	unsigned long flags;

	spin_lock_irqsave(&iommu->lock, flags);
	root = &iommu->root_entry[bus];
	context = get_context_addr_from_root(root);
	if (context) {
		context_clear_entry(context[devfn]);
		__iommu_flush_cache(iommu, &context[devfn], \
			sizeof(*context));
	}
	spin_unlock_irqrestore(&iommu->lock, flags);
}

static void free_context_table(struct intel_iommu *iommu)
{
	struct root_entry *root;
	int i;
	unsigned long flags;
	struct context_entry *context;

	spin_lock_irqsave(&iommu->lock, flags);
	if (!iommu->root_entry) {
		goto out;
	}
	for (i = 0; i < ROOT_ENTRY_NR; i++) {
		root = &iommu->root_entry[i];
		context = get_context_addr_from_root(root);
		if (context)
			free_pgtable_page(context);
	}
	free_pgtable_page(iommu->root_entry);
	iommu->root_entry = NULL;
out:
	spin_unlock_irqrestore(&iommu->lock, flags);
}

/* page table handling */
#define LEVEL_STRIDE		(9)
#define LEVEL_MASK		(((u64)1 << LEVEL_STRIDE) - 1)

static inline int agaw_to_level(int agaw)
{
	return agaw + 2;
}

static inline int agaw_to_width(int agaw)
{
	return 30 + agaw * LEVEL_STRIDE;

}

static inline int width_to_agaw(int width)
{
	return (width - 30) / LEVEL_STRIDE;
}

static inline unsigned int level_to_offset_bits(int level)
{
	return (12 + (level - 1) * LEVEL_STRIDE);
}

static inline int address_level_offset(u64 addr, int level)
{
	return ((addr >> level_to_offset_bits(level)) & LEVEL_MASK);
}

static inline u64 level_mask(int level)
{
	return ((u64)-1 << level_to_offset_bits(level));
}

static inline u64 level_size(int level)
{
	return ((u64)1 << level_to_offset_bits(level));
}

static inline u64 align_to_level(u64 addr, int level)
{
	return ((addr + level_size(level) - 1) & level_mask(level));
}

static struct dma_pte * addr_to_dma_pte(struct dmar_domain *domain, u64 addr)
{
	int addr_width = agaw_to_width(domain->agaw);
	struct dma_pte *parent, *pte = NULL;
	int level = agaw_to_level(domain->agaw);
	int offset;
	unsigned long flags;

	BUG_ON(!domain->pgd);

	addr &= (((u64)1) << addr_width) - 1;
	parent = domain->pgd;

	spin_lock_irqsave(&domain->mapping_lock, flags);
	while (level > 0) {
		void *tmp_page;

		offset = address_level_offset(addr, level);
		pte = &parent[offset];
		if (level == 1)
			break;

		if (!dma_pte_present(*pte)) {
			tmp_page = alloc_pgtable_page();

			if (!tmp_page) {
				spin_unlock_irqrestore(&domain->mapping_lock,
					flags);
				return NULL;
			}
			__iommu_flush_cache(domain->iommu, tmp_page,
					PAGE_SIZE_4K);
			dma_set_pte_addr(*pte, virt_to_phys(tmp_page));
			/*
			 * high level table always sets r/w, last level page
			 * table control read/write
			 */
			dma_set_pte_readable(*pte);
			dma_set_pte_writable(*pte);
			__iommu_flush_cache(domain->iommu, pte, sizeof(*pte));
		}
		parent = phys_to_virt(dma_pte_addr(*pte));
		level--;
	}

	spin_unlock_irqrestore(&domain->mapping_lock, flags);
	return pte;
}

/* return address's pte at specific level */
static struct dma_pte *dma_addr_level_pte(struct dmar_domain *domain, u64 addr,
		int level)
{
	struct dma_pte *parent, *pte = NULL;
	int total = agaw_to_level(domain->agaw);
	int offset;

	parent = domain->pgd;
	while (level <= total) {
		offset = address_level_offset(addr, total);
		pte = &parent[offset];
		if (level == total)
			return pte;

		if (!dma_pte_present(*pte))
			break;
		parent = phys_to_virt(dma_pte_addr(*pte));
		total--;
	}
	return NULL;
}

/* clear one page's page table */
static void dma_pte_clear_one(struct dmar_domain *domain, u64 addr)
{
	struct dma_pte *pte = NULL;

	/* get last level pte */
	pte = dma_addr_level_pte(domain, addr, 1);

	if (pte) {
		dma_clear_pte(*pte);
		__iommu_flush_cache(domain->iommu, pte, sizeof(*pte));
	}
}

/* clear last level pte, a tlb flush should be followed */
static void dma_pte_clear_range(struct dmar_domain *domain, u64 start, u64 end)
{
	int addr_width = agaw_to_width(domain->agaw);

	start &= (((u64)1) << addr_width) - 1;
	end &= (((u64)1) << addr_width) - 1;
	/* in case it's partial page */
	start = PAGE_ALIGN_4K(start);
	end &= PAGE_MASK_4K;

	/* we don't need lock here, nobody else touches the iova range */
	while (start < end) {
		dma_pte_clear_one(domain, start);
		start += PAGE_SIZE_4K;
	}
}

/* free page table pages. last level pte should already be cleared */
static void dma_pte_free_pagetable(struct dmar_domain *domain,
	u64 start, u64 end)
{
	int addr_width = agaw_to_width(domain->agaw);
	struct dma_pte *pte;
	int total = agaw_to_level(domain->agaw);
	int level;
	u64 tmp;

	start &= (((u64)1) << addr_width) - 1;
	end &= (((u64)1) << addr_width) - 1;

	/* we don't need lock here, nobody else touches the iova range */
	level = 2;
	while (level <= total) {
		tmp = align_to_level(start, level);
		if (tmp >= end || (tmp + level_size(level) > end))
			return;

		while (tmp < end) {
			pte = dma_addr_level_pte(domain, tmp, level);
			if (pte) {
				free_pgtable_page(
					phys_to_virt(dma_pte_addr(*pte)));
				dma_clear_pte(*pte);
				__iommu_flush_cache(domain->iommu,
						pte, sizeof(*pte));
			}
			tmp += level_size(level);
		}
		level++;
	}
	/* free pgd */
	if (start == 0 && end >= ((((u64)1) << addr_width) - 1)) {
		free_pgtable_page(domain->pgd);
		domain->pgd = NULL;
	}
}

/* iommu handling */
static int iommu_alloc_root_entry(struct intel_iommu *iommu)
{
	struct root_entry *root;
	unsigned long flags;

	root = (struct root_entry *)alloc_pgtable_page();
	if (!root)
		return -ENOMEM;

	__iommu_flush_cache(iommu, root, PAGE_SIZE_4K);

	spin_lock_irqsave(&iommu->lock, flags);
	iommu->root_entry = root;
	spin_unlock_irqrestore(&iommu->lock, flags);

	return 0;
}

#define IOMMU_WAIT_OP(iommu, offset, op, cond, sts) \
{\
	unsigned long start_time = jiffies;\
	while (1) {\
		sts = op (iommu->reg + offset);\
		if (cond)\
			break;\
		if (time_after(jiffies, start_time + DMAR_OPERATION_TIMEOUT))\
			panic("DMAR hardware is malfunctioning\n");\
		cpu_relax();\
	}\
}

static void iommu_set_root_entry(struct intel_iommu *iommu)
{
	void *addr;
	u32 cmd, sts;
	unsigned long flag;

	addr = iommu->root_entry;

	spin_lock_irqsave(&iommu->register_lock, flag);
	dmar_writeq(iommu->reg + DMAR_RTADDR_REG, virt_to_phys(addr));

	cmd = iommu->gcmd | DMA_GCMD_SRTP;
	writel(cmd, iommu->reg + DMAR_GCMD_REG);

	/* Make sure hardware complete it */
	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
		readl, (sts & DMA_GSTS_RTPS), sts);

	spin_unlock_irqrestore(&iommu->register_lock, flag);
}

static void iommu_flush_write_buffer(struct intel_iommu *iommu)
{
	u32 val;
	unsigned long flag;

	if (!cap_rwbf(iommu->cap))
		return;
	val = iommu->gcmd | DMA_GCMD_WBF;

	spin_lock_irqsave(&iommu->register_lock, flag);
	writel(val, iommu->reg + DMAR_GCMD_REG);

	/* Make sure hardware complete it */
	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
			readl, (!(val & DMA_GSTS_WBFS)), val);

	spin_unlock_irqrestore(&iommu->register_lock, flag);
}

/* return value determine if we need a write buffer flush */
static int __iommu_flush_context(struct intel_iommu *iommu,
	u16 did, u16 source_id, u8 function_mask, u64 type,
	int non_present_entry_flush)
{
	u64 val = 0;
	unsigned long flag;

	/*
	 * In the non-present entry flush case, if hardware doesn't cache
	 * non-present entry we do nothing and if hardware cache non-present
	 * entry, we flush entries of domain 0 (the domain id is used to cache
	 * any non-present entries)
	 */
	if (non_present_entry_flush) {
		if (!cap_caching_mode(iommu->cap))
			return 1;
		else
			did = 0;
	}

	switch (type) {
	case DMA_CCMD_GLOBAL_INVL:
		val = DMA_CCMD_GLOBAL_INVL;
		break;
	case DMA_CCMD_DOMAIN_INVL:
		val = DMA_CCMD_DOMAIN_INVL|DMA_CCMD_DID(did);
		break;
	case DMA_CCMD_DEVICE_INVL:
		val = DMA_CCMD_DEVICE_INVL|DMA_CCMD_DID(did)
			| DMA_CCMD_SID(source_id) | DMA_CCMD_FM(function_mask);
		break;
	default:
		BUG();
	}
	val |= DMA_CCMD_ICC;

	spin_lock_irqsave(&iommu->register_lock, flag);
	dmar_writeq(iommu->reg + DMAR_CCMD_REG, val);

	/* Make sure hardware complete it */
	IOMMU_WAIT_OP(iommu, DMAR_CCMD_REG,
		dmar_readq, (!(val & DMA_CCMD_ICC)), val);

	spin_unlock_irqrestore(&iommu->register_lock, flag);

	/* flush context entry will implictly flush write buffer */
	return 0;
}

static int inline iommu_flush_context_global(struct intel_iommu *iommu,
	int non_present_entry_flush)
{
	return __iommu_flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL,
		non_present_entry_flush);
}

static int inline iommu_flush_context_domain(struct intel_iommu *iommu, u16 did,
	int non_present_entry_flush)
{
	return __iommu_flush_context(iommu, did, 0, 0, DMA_CCMD_DOMAIN_INVL,
		non_present_entry_flush);
}

static int inline iommu_flush_context_device(struct intel_iommu *iommu,
	u16 did, u16 source_id, u8 function_mask, int non_present_entry_flush)
{
	return __iommu_flush_context(iommu, did, source_id, function_mask,
		DMA_CCMD_DEVICE_INVL, non_present_entry_flush);
}

/* return value determine if we need a write buffer flush */
static int __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did,
	u64 addr, unsigned int size_order, u64 type,
	int non_present_entry_flush)
{
	int tlb_offset = ecap_iotlb_offset(iommu->ecap);
	u64 val = 0, val_iva = 0;
	unsigned long flag;

	/*
	 * In the non-present entry flush case, if hardware doesn't cache
	 * non-present entry we do nothing and if hardware cache non-present
	 * entry, we flush entries of domain 0 (the domain id is used to cache
	 * any non-present entries)
	 */
	if (non_present_entry_flush) {
		if (!cap_caching_mode(iommu->cap))
			return 1;
		else
			did = 0;
	}

	switch (type) {
	case DMA_TLB_GLOBAL_FLUSH:
		/* global flush doesn't need set IVA_REG */
		val = DMA_TLB_GLOBAL_FLUSH|DMA_TLB_IVT;
		break;
	case DMA_TLB_DSI_FLUSH:
		val = DMA_TLB_DSI_FLUSH|DMA_TLB_IVT|DMA_TLB_DID(did);
		break;
	case DMA_TLB_PSI_FLUSH:
		val = DMA_TLB_PSI_FLUSH|DMA_TLB_IVT|DMA_TLB_DID(did);
		/* Note: always flush non-leaf currently */
		val_iva = size_order | addr;
		break;
	default:
		BUG();
	}
	/* Note: set drain read/write */
#if 0
	/*
	 * This is probably to be super secure.. Looks like we can
	 * ignore it without any impact.
	 */
	if (cap_read_drain(iommu->cap))
		val |= DMA_TLB_READ_DRAIN;
#endif
	if (cap_write_drain(iommu->cap))
		val |= DMA_TLB_WRITE_DRAIN;

	spin_lock_irqsave(&iommu->register_lock, flag);
	/* Note: Only uses first TLB reg currently */
	if (val_iva)
		dmar_writeq(iommu->reg + tlb_offset, val_iva);
	dmar_writeq(iommu->reg + tlb_offset + 8, val);

	/* Make sure hardware complete it */
	IOMMU_WAIT_OP(iommu, tlb_offset + 8,
		dmar_readq, (!(val & DMA_TLB_IVT)), val);

	spin_unlock_irqrestore(&iommu->register_lock, flag);

	/* check IOTLB invalidation granularity */
	if (DMA_TLB_IAIG(val) == 0)
		printk(KERN_ERR"IOMMU: flush IOTLB failed\n");
	if (DMA_TLB_IAIG(val) != DMA_TLB_IIRG(type))
		pr_debug("IOMMU: tlb flush request %Lx, actual %Lx\n",
			DMA_TLB_IIRG(type), DMA_TLB_IAIG(val));
	/* flush context entry will implictly flush write buffer */
	return 0;
}

static int inline iommu_flush_iotlb_global(struct intel_iommu *iommu,
	int non_present_entry_flush)
{
	return __iommu_flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH,
		non_present_entry_flush);
}

static int inline iommu_flush_iotlb_dsi(struct intel_iommu *iommu, u16 did,
	int non_present_entry_flush)
{
	return __iommu_flush_iotlb(iommu, did, 0, 0, DMA_TLB_DSI_FLUSH,
		non_present_entry_flush);
}

static int iommu_get_alignment(u64 base, unsigned int size)
{
	int t = 0;
	u64 end;

	end = base + size - 1;
	while (base != end) {
		t++;
		base >>= 1;
		end >>= 1;
	}
	return t;
}

static int iommu_flush_iotlb_psi(struct intel_iommu *iommu, u16 did,
	u64 addr, unsigned int pages, int non_present_entry_flush)
{
	unsigned int align;

	BUG_ON(addr & (~PAGE_MASK_4K));
	BUG_ON(pages == 0);

	/* Fallback to domain selective flush if no PSI support */
	if (!cap_pgsel_inv(iommu->cap))
		return iommu_flush_iotlb_dsi(iommu, did,
			non_present_entry_flush);

	/*
	 * PSI requires page size to be 2 ^ x, and the base address is naturally
	 * aligned to the size
	 */
	align = iommu_get_alignment(addr >> PAGE_SHIFT_4K, pages);
	/* Fallback to domain selective flush if size is too big */
	if (align > cap_max_amask_val(iommu->cap))
		return iommu_flush_iotlb_dsi(iommu, did,
			non_present_entry_flush);

	addr >>= PAGE_SHIFT_4K + align;
	addr <<= PAGE_SHIFT_4K + align;

	return __iommu_flush_iotlb(iommu, did, addr, align,
		DMA_TLB_PSI_FLUSH, non_present_entry_flush);
}

static int iommu_enable_translation(struct intel_iommu *iommu)
{
	u32 sts;
	unsigned long flags;

	spin_lock_irqsave(&iommu->register_lock, flags);
	writel(iommu->gcmd|DMA_GCMD_TE, iommu->reg + DMAR_GCMD_REG);

	/* Make sure hardware complete it */
	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
		readl, (sts & DMA_GSTS_TES), sts);

	iommu->gcmd |= DMA_GCMD_TE;
	spin_unlock_irqrestore(&iommu->register_lock, flags);
	return 0;
}

static int iommu_disable_translation(struct intel_iommu *iommu)
{
	u32 sts;
	unsigned long flag;

	spin_lock_irqsave(&iommu->register_lock, flag);
	iommu->gcmd &= ~DMA_GCMD_TE;
	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);

	/* Make sure hardware complete it */
	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
		readl, (!(sts & DMA_GSTS_TES)), sts);

	spin_unlock_irqrestore(&iommu->register_lock, flag);
	return 0;
}

static int iommu_init_domains(struct intel_iommu *iommu)
{
	unsigned long ndomains;
	unsigned long nlongs;

	ndomains = cap_ndoms(iommu->cap);
	pr_debug("Number of Domains supportd <%ld>\n", ndomains);
	nlongs = BITS_TO_LONGS(ndomains);

	/* TBD: there might be 64K domains,
	 * consider other allocation for future chip
	 */
	iommu->domain_ids = kcalloc(nlongs, sizeof(unsigned long), GFP_KERNEL);
	if (!iommu->domain_ids) {
		printk(KERN_ERR "Allocating domain id array failed\n");
		return -ENOMEM;
	}
	iommu->domains = kcalloc(ndomains, sizeof(struct dmar_domain *),
			GFP_KERNEL);
	if (!iommu->domains) {
		printk(KERN_ERR "Allocating domain array failed\n");
		kfree(iommu->domain_ids);
		return -ENOMEM;
	}

	/*
	 * if Caching mode is set, then invalid translations are tagged
	 * with domainid 0. Hence we need to pre-allocate it.
	 */
	if (cap_caching_mode(iommu->cap))
		set_bit(0, iommu->domain_ids);
	return 0;
}

static struct intel_iommu *alloc_iommu(struct dmar_drhd_unit *drhd)
{
	struct intel_iommu *iommu;
	int ret;
	int map_size;
	u32 ver;

	iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
	if (!iommu)
		return NULL;
	iommu->reg = ioremap(drhd->reg_base_addr, PAGE_SIZE_4K);
	if (!iommu->reg) {
		printk(KERN_ERR "IOMMU: can't map the region\n");
		goto error;
	}
	iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
	iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);

	/* the registers might be more than one page */
	map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap),
		cap_max_fault_reg_offset(iommu->cap));
	map_size = PAGE_ALIGN_4K(map_size);
	if (map_size > PAGE_SIZE_4K) {
		iounmap(iommu->reg);
		iommu->reg = ioremap(drhd->reg_base_addr, map_size);
		if (!iommu->reg) {
			printk(KERN_ERR "IOMMU: can't map the region\n");
			goto error;
		}
	}

	ver = readl(iommu->reg + DMAR_VER_REG);
	pr_debug("IOMMU %llx: ver %d:%d cap %llx ecap %llx\n",
		drhd->reg_base_addr, DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver),
		iommu->cap, iommu->ecap);
	ret = iommu_init_domains(iommu);
	if (ret)
		goto error_unmap;
	spin_lock_init(&iommu->lock);
	spin_lock_init(&iommu->register_lock);

	drhd->iommu = iommu;
	return iommu;
error_unmap:
	iounmap(iommu->reg);
	iommu->reg = 0;
error:
	kfree(iommu);
	return NULL;
}

static void domain_exit(struct dmar_domain *domain);
static void free_iommu(struct intel_iommu *iommu)
{
	struct dmar_domain *domain;
	int i;

	if (!iommu)
		return;

	i = find_first_bit(iommu->domain_ids, cap_ndoms(iommu->cap));
	for (; i < cap_ndoms(iommu->cap); ) {
		domain = iommu->domains[i];
		clear_bit(i, iommu->domain_ids);
		domain_exit(domain);
		i = find_next_bit(iommu->domain_ids,
			cap_ndoms(iommu->cap), i+1);
	}

	if (iommu->gcmd & DMA_GCMD_TE)
		iommu_disable_translation(iommu);

	if (iommu->irq) {
		set_irq_data(iommu->irq, NULL);
		/* This will mask the irq */
		free_irq(iommu->irq, iommu);
		destroy_irq(iommu->irq);
	}

	kfree(iommu->domains);
	kfree(iommu->domain_ids);

	/* free context mapping */
	free_context_table(iommu);

	if (iommu->reg)
		iounmap(iommu->reg);
	kfree(iommu);
}

static struct dmar_domain * iommu_alloc_domain(struct intel_iommu *iommu)
{
	unsigned long num;
	unsigned long ndomains;
	struct dmar_domain *domain;
	unsigned long flags;

	domain = alloc_domain_mem();
	if (!domain)
		return NULL;

	ndomains = cap_ndoms(iommu->cap);

	spin_lock_irqsave(&iommu->lock, flags);
	num = find_first_zero_bit(iommu->domain_ids, ndomains);
	if (num >= ndomains) {
		spin_unlock_irqrestore(&iommu->lock, flags);
		free_domain_mem(domain);
		printk(KERN_ERR "IOMMU: no free domain ids\n");
		return NULL;
	}

	set_bit(num, iommu->domain_ids);
	domain->id = num;
	domain->iommu = iommu;
	iommu->domains[num] = domain;
	spin_unlock_irqrestore(&iommu->lock, flags);

	return domain;
}

static void iommu_free_domain(struct dmar_domain *domain)
{
	unsigned long flags;

	spin_lock_irqsave(&domain->iommu->lock, flags);
	clear_bit(domain->id, domain->iommu->domain_ids);
	spin_unlock_irqrestore(&domain->iommu->lock, flags);
}

static struct iova_domain reserved_iova_list;

static void dmar_init_reserved_ranges(void)
{
	struct pci_dev *pdev = NULL;
	struct iova *iova;
	int i;
	u64 addr, size;

	init_iova_domain(&reserved_iova_list);

	/* IOAPIC ranges shouldn't be accessed by DMA */
	iova = reserve_iova(&reserved_iova_list, IOVA_PFN(IOAPIC_RANGE_START),
		IOVA_PFN(IOAPIC_RANGE_END));
	if (!iova)
		printk(KERN_ERR "Reserve IOAPIC range failed\n");

	/* Reserve all PCI MMIO to avoid peer-to-peer access */
	for_each_pci_dev(pdev) {
		struct resource *r;

		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
			r = &pdev->resource[i];
			if (!r->flags || !(r->flags & IORESOURCE_MEM))
				continue;
			addr = r->start;
			addr &= PAGE_MASK_4K;
			size = r->end - addr;
			size = PAGE_ALIGN_4K(size);
			iova = reserve_iova(&reserved_iova_list, IOVA_PFN(addr),
				IOVA_PFN(size + addr) - 1);
			if (!iova)
				printk(KERN_ERR "Reserve iova failed\n");
		}
	}

}

static void domain_reserve_special_ranges(struct dmar_domain *domain)
{
	copy_reserved_iova(&reserved_iova_list, &domain->iovad);
}

static inline int guestwidth_to_adjustwidth(int gaw)
{
	int agaw;
	int r = (gaw - 12) % 9;

	if (r == 0)
		agaw = gaw;
	else
		agaw = gaw + 9 - r;
	if (agaw > 64)
		agaw = 64;
	return agaw;
}

static int domain_init(struct dmar_domain *domain, int guest_width)
{
	struct intel_iommu *iommu;
	int adjust_width, agaw;
	unsigned long sagaw;

	init_iova_domain(&domain->iovad);
	spin_lock_init(&domain->mapping_lock);

	domain_reserve_special_ranges(domain);

	/* calculate AGAW */
	iommu = domain->iommu;
	if (guest_width > cap_mgaw(iommu->cap))
		guest_width = cap_mgaw(iommu->cap);
	domain->gaw = guest_width;
	adjust_width = guestwidth_to_adjustwidth(guest_width);
	agaw = width_to_agaw(adjust_width);
	sagaw = cap_sagaw(iommu->cap);
	if (!test_bit(agaw, &sagaw)) {
		/* hardware doesn't support it, choose a bigger one */
		pr_debug("IOMMU: hardware doesn't support agaw %d\n", agaw);
		agaw = find_next_bit(&sagaw, 5, agaw);
		if (agaw >= 5)
			return -ENODEV;
	}
	domain->agaw = agaw;
	INIT_LIST_HEAD(&domain->devices);

	/* always allocate the top pgd */
	domain->pgd = (struct dma_pte *)alloc_pgtable_page();
	if (!domain->pgd)
		return -ENOMEM;
	__iommu_flush_cache(iommu, domain->pgd, PAGE_SIZE_4K);
	return 0;
}

static void domain_exit(struct dmar_domain *domain)
{
	u64 end;

	/* Domain 0 is reserved, so dont process it */
	if (!domain)
		return;

	domain_remove_dev_info(domain);
	/* destroy iovas */
	put_iova_domain(&domain->iovad);
	end = DOMAIN_MAX_ADDR(domain->gaw);
	end = end & (~PAGE_MASK_4K);

	/* clear ptes */
	dma_pte_clear_range(domain, 0, end);

	/* free page tables */
	dma_pte_free_pagetable(domain, 0, end);

	iommu_free_domain(domain);
	free_domain_mem(domain);
}

static int domain_context_mapping_one(struct dmar_domain *domain,
		u8 bus, u8 devfn)
{
	struct context_entry *context;
	struct intel_iommu *iommu = domain->iommu;
	unsigned long flags;

	pr_debug("Set context mapping for %02x:%02x.%d\n",
		bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
	BUG_ON(!domain->pgd);
	context = device_to_context_entry(iommu, bus, devfn);
	if (!context)
		return -ENOMEM;
	spin_lock_irqsave(&iommu->lock, flags);
	if (context_present(*context)) {
		spin_unlock_irqrestore(&iommu->lock, flags);
		return 0;
	}

	context_set_domain_id(*context, domain->id);
	context_set_address_width(*context, domain->agaw);
	context_set_address_root(*context, virt_to_phys(domain->pgd));
	context_set_translation_type(*context, CONTEXT_TT_MULTI_LEVEL);
	context_set_fault_enable(*context);
	context_set_present(*context);
	__iommu_flush_cache(iommu, context, sizeof(*context));

	/* it's a non-present to present mapping */
	if (iommu_flush_context_device(iommu, domain->id,
			(((u16)bus) << 8) | devfn, DMA_CCMD_MASK_NOBIT, 1))
		iommu_flush_write_buffer(iommu);
	else
		iommu_flush_iotlb_dsi(iommu, 0, 0);
	spin_unlock_irqrestore(&iommu->lock, flags);
	return 0;
}

static int
domain_context_mapping(struct dmar_domain *domain, struct pci_dev *pdev)
{
	int ret;
	struct pci_dev *tmp, *parent;

	ret = domain_context_mapping_one(domain, pdev->bus->number,
		pdev->devfn);
	if (ret)
		return ret;

	/* dependent device mapping */
	tmp = pci_find_upstream_pcie_bridge(pdev);
	if (!tmp)
		return 0;
	/* Secondary interface's bus number and devfn 0 */
	parent = pdev->bus->self;
	while (parent != tmp) {
		ret = domain_context_mapping_one(domain, parent->bus->number,
			parent->devfn);
		if (ret)
			return ret;
		parent = parent->bus->self;
	}
	if (tmp->is_pcie) /* this is a PCIE-to-PCI bridge */
		return domain_context_mapping_one(domain,
			tmp->subordinate->number, 0);
	else /* this is a legacy PCI bridge */
		return domain_context_mapping_one(domain,
			tmp->bus->number, tmp->devfn);
}

static int domain_context_mapped(struct dmar_domain *domain,
	struct pci_dev *pdev)
{
	int ret;
	struct pci_dev *tmp, *parent;

	ret = device_context_mapped(domain->iommu,
		pdev->bus->number, pdev->devfn);
	if (!ret)
		return ret;
	/* dependent device mapping */
	tmp = pci_find_upstream_pcie_bridge(pdev);
	if (!tmp)
		return ret;
	/* Secondary interface's bus number and devfn 0 */
	parent = pdev->bus->self;
	while (parent != tmp) {
		ret = device_context_mapped(domain->iommu, parent->bus->number,
			parent->devfn);
		if (!ret)
			return ret;
		parent = parent->bus->self;
	}
	if (tmp->is_pcie)
		return device_context_mapped(domain->iommu,
			tmp->subordinate->number, 0);
	else
		return device_context_mapped(domain->iommu,
			tmp->bus->number, tmp->devfn);
}

static int
domain_page_mapping(struct dmar_domain *domain, dma_addr_t iova,
			u64 hpa, size_t size, int prot)
{
	u64 start_pfn, end_pfn;
	struct dma_pte *pte;
	int index;

	if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
		return -EINVAL;
	iova &= PAGE_MASK_4K;
	start_pfn = ((u64)hpa) >> PAGE_SHIFT_4K;
	end_pfn = (PAGE_ALIGN_4K(((u64)hpa) + size)) >> PAGE_SHIFT_4K;
	index = 0;
	while (start_pfn < end_pfn) {
		pte = addr_to_dma_pte(domain, iova + PAGE_SIZE_4K * index);
		if (!pte)
			return -ENOMEM;
		/* We don't need lock here, nobody else
		 * touches the iova range
		 */
		BUG_ON(dma_pte_addr(*pte));
		dma_set_pte_addr(*pte, start_pfn << PAGE_SHIFT_4K);
		dma_set_pte_prot(*pte, prot);
		__iommu_flush_cache(domain->iommu, pte, sizeof(*pte));
		start_pfn++;
		index++;
	}
	return 0;
}

static void detach_domain_for_dev(struct dmar_domain *domain, u8 bus, u8 devfn)
{
	clear_context_table(domain->iommu, bus, devfn);
	iommu_flush_context_global(domain->iommu, 0);
	iommu_flush_iotlb_global(domain->iommu, 0);
}

static void domain_remove_dev_info(struct dmar_domain *domain)
{
	struct device_domain_info *info;
	unsigned long flags;

	spin_lock_irqsave(&device_domain_lock, flags);
	while (!list_empty(&domain->devices)) {
		info = list_entry(domain->devices.next,
			struct device_domain_info, link);
		list_del(&info->link);
		list_del(&info->global);
		if (info->dev)
			info->dev->sysdata = NULL;
		spin_unlock_irqrestore(&device_domain_lock, flags);

		detach_domain_for_dev(info->domain, info->bus, info->devfn);
		free_devinfo_mem(info);

		spin_lock_irqsave(&device_domain_lock, flags);
	}
	spin_unlock_irqrestore(&device_domain_lock, flags);
}

/*
 * find_domain
 * Note: we use struct pci_dev->sysdata stores the info
 */
struct dmar_domain *
find_domain(struct pci_dev *pdev)
{
	struct device_domain_info *info;

	/* No lock here, assumes no domain exit in normal case */
	info = pdev->sysdata;
	if (info)
		return info->domain;
	return NULL;
}

static int dmar_pci_device_match(struct pci_dev *devices[], int cnt,
     struct pci_dev *dev)
{
	int index;

	while (dev) {
		for (index = 0; index < cnt; index ++)
			if (dev == devices[index])
				return 1;

		/* Check our parent */
		dev = dev->bus->self;
	}

	return 0;
}

static struct dmar_drhd_unit *
dmar_find_matched_drhd_unit(struct pci_dev *dev)
{
	struct dmar_drhd_unit *drhd = NULL;

	list_for_each_entry(drhd, &dmar_drhd_units, list) {
		if (drhd->include_all || dmar_pci_device_match(drhd->devices,
						drhd->devices_cnt, dev))
			return drhd;
	}

	return NULL;
}

/* domain is initialized */
static struct dmar_domain *get_domain_for_dev(struct pci_dev *pdev, int gaw)
{
	struct dmar_domain *domain, *found = NULL;
	struct intel_iommu *iommu;
	struct dmar_drhd_unit *drhd;
	struct device_domain_info *info, *tmp;
	struct pci_dev *dev_tmp;
	unsigned long flags;
	int bus = 0, devfn = 0;

	domain = find_domain(pdev);
	if (domain)
		return domain;

	dev_tmp = pci_find_upstream_pcie_bridge(pdev);
	if (dev_tmp) {
		if (dev_tmp->is_pcie) {
			bus = dev_tmp->subordinate->number;
			devfn = 0;
		} else {
			bus = dev_tmp->bus->number;
			devfn = dev_tmp->devfn;
		}
		spin_lock_irqsave(&device_domain_lock, flags);
		list_for_each_entry(info, &device_domain_list, global) {
			if (info->bus == bus && info->devfn == devfn) {
				found = info->domain;
				break;
			}
		}
		spin_unlock_irqrestore(&device_domain_lock, flags);
		/* pcie-pci bridge already has a domain, uses it */
		if (found) {
			domain = found;
			goto found_domain;
		}
	}

	/* Allocate new domain for the device */
	drhd = dmar_find_matched_drhd_unit(pdev);
	if (!drhd) {
		printk(KERN_ERR "IOMMU: can't find DMAR for device %s\n",
			pci_name(pdev));
		return NULL;
	}
	iommu = drhd->iommu;

	domain = iommu_alloc_domain(iommu);
	if (!domain)
		goto error;

	if (domain_init(domain, gaw)) {
		domain_exit(domain);
		goto error;
	}

	/* register pcie-to-pci device */
	if (dev_tmp) {
		info = alloc_devinfo_mem();
		if (!info) {
			domain_exit(domain);
			goto error;
		}
		info->bus = bus;
		info->devfn = devfn;
		info->dev = NULL;
		info->domain = domain;
		/* This domain is shared by devices under p2p bridge */
		domain->flags |= DOMAIN_FLAG_MULTIPLE_DEVICES;

		/* pcie-to-pci bridge already has a domain, uses it */
		found = NULL;
		spin_lock_irqsave(&device_domain_lock, flags);
		list_for_each_entry(tmp, &device_domain_list, global) {
			if (tmp->bus == bus && tmp->devfn == devfn) {
				found = tmp->domain;
				break;
			}
		}
		if (found) {
			free_devinfo_mem(info);
			domain_exit(domain);
			domain = found;
		} else {
			list_add(&info->link, &domain->devices);
			list_add(&info->global, &device_domain_list);
		}
		spin_unlock_irqrestore(&device_domain_lock, flags);
	}

found_domain:
	info = alloc_devinfo_mem();
	if (!info)
		goto error;
	info->bus = pdev->bus->number;
	info->devfn = pdev->devfn;
	info->dev = pdev;
	info->domain = domain;
	spin_lock_irqsave(&device_domain_lock, flags);
	/* somebody is fast */
	found = find_domain(pdev);
	if (found != NULL) {
		spin_unlock_irqrestore(&device_domain_lock, flags);
		if (found != domain) {
			domain_exit(domain);
			domain = found;
		}
		free_devinfo_mem(info);
		return domain;
	}
	list_add(&info->link, &domain->devices);
	list_add(&info->global, &device_domain_list);
	pdev->sysdata = info;
	spin_unlock_irqrestore(&device_domain_lock, flags);
	return domain;
error:
	/* recheck it here, maybe others set it */
	return find_domain(pdev);
}

static int iommu_prepare_identity_map(struct pci_dev *pdev, u64 start, u64 end)
{
	struct dmar_domain *domain;
	unsigned long size;
	u64 base;
	int ret;

	printk(KERN_INFO
		"IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
		pci_name(pdev), start, end);
	/* page table init */
	domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
	if (!domain)
		return -ENOMEM;

	/* The address might not be aligned */
	base = start & PAGE_MASK_4K;
	size = end - base;
	size = PAGE_ALIGN_4K(size);
	if (!reserve_iova(&domain->iovad, IOVA_PFN(base),
			IOVA_PFN(base + size) - 1)) {
		printk(KERN_ERR "IOMMU: reserve iova failed\n");
		ret = -ENOMEM;
		goto error;
	}

	pr_debug("Mapping reserved region %lx@%llx for %s\n",
		size, base, pci_name(pdev));
	/*
	 * RMRR range might have overlap with physical memory range,
	 * clear it first
	 */
	dma_pte_clear_range(domain, base, base + size);

	ret = domain_page_mapping(domain, base, base, size,
		DMA_PTE_READ|DMA_PTE_WRITE);
	if (ret)
		goto error;

	/* context entry init */
	ret = domain_context_mapping(domain, pdev);
	if (!ret)
		return 0;
error:
	domain_exit(domain);
	return ret;

}

static inline int iommu_prepare_rmrr_dev(struct dmar_rmrr_unit *rmrr,
	struct pci_dev *pdev)
{
	if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO)
		return 0;
	return iommu_prepare_identity_map(pdev, rmrr->base_address,
		rmrr->end_address + 1);
}

int __init init_dmars(void)
{
	struct dmar_drhd_unit *drhd;
	struct dmar_rmrr_unit *rmrr;
	struct pci_dev *pdev;
	struct intel_iommu *iommu;
	int ret, unit = 0;

	/*
	 * for each drhd
	 *    allocate root
	 *    initialize and program root entry to not present
	 * endfor
	 */
	for_each_drhd_unit(drhd) {
		if (drhd->ignored)
			continue;
		iommu = alloc_iommu(drhd);
		if (!iommu) {
			ret = -ENOMEM;
			goto error;
		}

		/*
		 * TBD:
		 * we could share the same root & context tables
		 * amoung all IOMMU's. Need to Split it later.
		 */
		ret = iommu_alloc_root_entry(iommu);
		if (ret) {
			printk(KERN_ERR "IOMMU: allocate root entry failed\n");
			goto error;
		}
	}

	/*
	 * For each rmrr
	 *   for each dev attached to rmrr
	 *   do
	 *     locate drhd for dev, alloc domain for dev
	 *     allocate free domain
	 *     allocate page table entries for rmrr
	 *     if context not allocated for bus
	 *           allocate and init context
	 *           set present in root table for this bus
	 *     init context with domain, translation etc
	 *    endfor
	 * endfor
	 */
	for_each_rmrr_units(rmrr) {
		int i;
		for (i = 0; i < rmrr->devices_cnt; i++) {
			pdev = rmrr->devices[i];
			/* some BIOS lists non-exist devices in DMAR table */
			if (!pdev)
				continue;
			ret = iommu_prepare_rmrr_dev(rmrr, pdev);
			if (ret)
				printk(KERN_ERR
				 "IOMMU: mapping reserved region failed\n");
		}
	}

	/*
	 * for each drhd
	 *   enable fault log
	 *   global invalidate context cache
	 *   global invalidate iotlb
	 *   enable translation
	 */
	for_each_drhd_unit(drhd) {
		if (drhd->ignored)
			continue;
		iommu = drhd->iommu;
		sprintf (iommu->name, "dmar%d", unit++);

		iommu_flush_write_buffer(iommu);

		iommu_set_root_entry(iommu);

		iommu_flush_context_global(iommu, 0);
		iommu_flush_iotlb_global(iommu, 0);

		ret = iommu_enable_translation(iommu);
		if (ret)
			goto error;
	}

	return 0;
error:
	for_each_drhd_unit(drhd) {
		if (drhd->ignored)
			continue;
		iommu = drhd->iommu;
		free_iommu(iommu);
	}
	return ret;
}

static inline u64 aligned_size(u64 host_addr, size_t size)
{
	u64 addr;
	addr = (host_addr & (~PAGE_MASK_4K)) + size;
	return PAGE_ALIGN_4K(addr);
}

struct iova *
iommu_alloc_iova(struct dmar_domain *domain, void *host_addr, size_t size,
		u64 start, u64 end)
{
	u64 start_addr;
	struct iova *piova;

	/* Make sure it's in range */
	if ((start > DOMAIN_MAX_ADDR(domain->gaw)) || end < start)
		return NULL;

	end = min_t(u64, DOMAIN_MAX_ADDR(domain->gaw), end);
	start_addr = PAGE_ALIGN_4K(start);
	size = aligned_size((u64)host_addr, size);
	if (!size || (start_addr + size > end))
		return NULL;

	piova = alloc_iova(&domain->iovad,
			size >> PAGE_SHIFT_4K, IOVA_PFN(end));

	return piova;
}

static dma_addr_t __intel_map_single(struct device *dev, void *addr,
	size_t size, int dir, u64 *flush_addr, unsigned int *flush_size)
{
	struct dmar_domain *domain;
	struct pci_dev *pdev = to_pci_dev(dev);
	int ret;
	int prot = 0;
	struct iova *iova = NULL;
	u64 start_addr;

	addr = (void *)virt_to_phys(addr);

	domain = get_domain_for_dev(pdev,
			DEFAULT_DOMAIN_ADDRESS_WIDTH);
	if (!domain) {
		printk(KERN_ERR
			"Allocating domain for %s failed", pci_name(pdev));
		return 0;
	}

	start_addr = IOVA_START_ADDR;

	if (pdev->dma_mask <= DMA_32BIT_MASK) {
		iova = iommu_alloc_iova(domain, addr, size, start_addr,
			pdev->dma_mask);
	} else  {
		/*
		 * First try to allocate an io virtual address in
		 * DMA_32BIT_MASK and if that fails then try allocating
		 * from higer range
		 */
		iova = iommu_alloc_iova(domain, addr, size, start_addr,
			DMA_32BIT_MASK);
		if (!iova)
			iova = iommu_alloc_iova(domain, addr, size, start_addr,
			pdev->dma_mask);
	}

	if (!iova) {
		printk(KERN_ERR"Allocating iova for %s failed", pci_name(pdev));
		return 0;
	}

	/* make sure context mapping is ok */
	if (unlikely(!domain_context_mapped(domain, pdev))) {
		ret = domain_context_mapping(domain, pdev);
		if (ret)
			goto error;
	}

	/*
	 * Check if DMAR supports zero-length reads on write only
	 * mappings..
	 */
	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL || \
			!cap_zlr(domain->iommu->cap))
		prot |= DMA_PTE_READ;
	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
		prot |= DMA_PTE_WRITE;
	/*
	 * addr - (addr + size) might be partial page, we should map the whole
	 * page.  Note: if two part of one page are separately mapped, we
	 * might have two guest_addr mapping to the same host addr, but this
	 * is not a big problem
	 */
	ret = domain_page_mapping(domain, iova->pfn_lo << PAGE_SHIFT_4K,
		((u64)addr) & PAGE_MASK_4K,
		(iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT_4K, prot);
	if (ret)
		goto error;

	pr_debug("Device %s request: %lx@%llx mapping: %lx@%llx, dir %d\n",
		pci_name(pdev), size, (u64)addr,
		(iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT_4K,
		(u64)(iova->pfn_lo << PAGE_SHIFT_4K), dir);

	*flush_addr = iova->pfn_lo << PAGE_SHIFT_4K;
	*flush_size = (iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT_4K;
	return (iova->pfn_lo << PAGE_SHIFT_4K) + ((u64)addr & (~PAGE_MASK_4K));
error:
	__free_iova(&domain->iovad, iova);
	printk(KERN_ERR"Device %s request: %lx@%llx dir %d --- failed\n",
		pci_name(pdev), size, (u64)addr, dir);
	return 0;
}

static dma_addr_t intel_map_single(struct device *hwdev, void *addr,
	size_t size, int dir)
{
	struct pci_dev *pdev = to_pci_dev(hwdev);
	dma_addr_t ret;
	struct dmar_domain *domain;
	u64 flush_addr;
	unsigned int flush_size;

	BUG_ON(dir == DMA_NONE);
	if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO)
		return virt_to_bus(addr);

	ret = __intel_map_single(hwdev, addr, size,
			dir, &flush_addr, &flush_size);
	if (ret) {
		domain = find_domain(pdev);
		/* it's a non-present to present mapping */
		if (iommu_flush_iotlb_psi(domain->iommu, domain->id,
				flush_addr, flush_size >> PAGE_SHIFT_4K, 1))
			iommu_flush_write_buffer(domain->iommu);
	}
	return ret;
}

static void __intel_unmap_single(struct device *dev, dma_addr_t dev_addr,
	size_t size, int dir, u64 *flush_addr, unsigned int *flush_size)
{
	struct dmar_domain *domain;
	struct pci_dev *pdev = to_pci_dev(dev);
	struct iova *iova;

	domain = find_domain(pdev);
	BUG_ON(!domain);

	iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
	if (!iova) {
		*flush_size = 0;
		return;
	}
	pr_debug("Device %s unmapping: %lx@%llx\n",
		pci_name(pdev),
		(iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT_4K,
		(u64)(iova->pfn_lo << PAGE_SHIFT_4K));

	*flush_addr = iova->pfn_lo << PAGE_SHIFT_4K;
	*flush_size = (iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT_4K;
	/*  clear the whole page, not just dev_addr - (dev_addr + size) */
	dma_pte_clear_range(domain, *flush_addr, *flush_addr + *flush_size);
	/* free page tables */
	dma_pte_free_pagetable(domain, *flush_addr, *flush_addr + *flush_size);
	/* free iova */
	__free_iova(&domain->iovad, iova);
}

static void intel_unmap_single(struct device *dev, dma_addr_t dev_addr,
	size_t size, int dir)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct dmar_domain *domain;
	u64 flush_addr;
	unsigned int flush_size;

	if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO)
		return;

	domain = find_domain(pdev);
	__intel_unmap_single(dev, dev_addr, size,
		dir, &flush_addr, &flush_size);
	if (flush_size == 0)
		return;
	if (iommu_flush_iotlb_psi(domain->iommu, domain->id, flush_addr,
			flush_size >> PAGE_SHIFT_4K, 0))
		iommu_flush_write_buffer(domain->iommu);
}

static void * intel_alloc_coherent(struct device *hwdev, size_t size,
		       dma_addr_t *dma_handle, gfp_t flags)
{
	void *vaddr;
	int order;

	size = PAGE_ALIGN_4K(size);
	order = get_order(size);
	flags &= ~(GFP_DMA | GFP_DMA32);

	vaddr = (void *)__get_free_pages(flags, order);
	if (!vaddr)
		return NULL;
	memset(vaddr, 0, size);

	*dma_handle = intel_map_single(hwdev, vaddr, size, DMA_BIDIRECTIONAL);
	if (*dma_handle)
		return vaddr;
	free_pages((unsigned long)vaddr, order);
	return NULL;
}

static void intel_free_coherent(struct device *hwdev, size_t size,
	void *vaddr, dma_addr_t dma_handle)
{
	int order;

	size = PAGE_ALIGN_4K(size);
	order = get_order(size);

	intel_unmap_single(hwdev, dma_handle, size, DMA_BIDIRECTIONAL);
	free_pages((unsigned long)vaddr, order);
}

static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sg,
	int nelems, int dir)
{
	int i;
	struct pci_dev *pdev = to_pci_dev(hwdev);
	struct dmar_domain *domain;
	u64 flush_addr;
	unsigned int flush_size;

	if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO)
		return;

	domain = find_domain(pdev);
	for (i = 0; i < nelems; i++, sg++)
		__intel_unmap_single(hwdev, sg->dma_address,
			sg->dma_length, dir, &flush_addr, &flush_size);

	if (iommu_flush_iotlb_dsi(domain->iommu, domain->id, 0))
		iommu_flush_write_buffer(domain->iommu);
}

#define SG_ENT_VIRT_ADDRESS(sg)	(page_address((sg)->page) + (sg)->offset)
static int intel_nontranslate_map_sg(struct device *hddev,
	struct scatterlist *sg, int nelems, int dir)
{
	int i;

	for (i = 0; i < nelems; i++) {
		struct scatterlist *s = &sg[i];
		BUG_ON(!s->page);
		s->dma_address = virt_to_bus(SG_ENT_VIRT_ADDRESS(s));
		s->dma_length = s->length;
	}
	return nelems;
}

static int intel_map_sg(struct device *hwdev, struct scatterlist *sg,
	int nelems, int dir)
{
	void *addr;
	int i;
	dma_addr_t dma_handle;
	struct pci_dev *pdev = to_pci_dev(hwdev);
	struct dmar_domain *domain;
	u64 flush_addr;
	unsigned int flush_size;

	BUG_ON(dir == DMA_NONE);
	if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO)
		return intel_nontranslate_map_sg(hwdev, sg, nelems, dir);

	for (i = 0; i < nelems; i++, sg++) {
		addr = SG_ENT_VIRT_ADDRESS(sg);
		dma_handle = __intel_map_single(hwdev, addr,
				sg->length, dir, &flush_addr, &flush_size);
		if (!dma_handle) {
			intel_unmap_sg(hwdev, sg - i, i, dir);
			sg[0].dma_length = 0;
			return 0;
		}
		sg->dma_address = dma_handle;
		sg->dma_length = sg->length;
	}

	domain = find_domain(pdev);

	/* it's a non-present to present mapping */
	if (iommu_flush_iotlb_dsi(domain->iommu, domain->id, 1))
		iommu_flush_write_buffer(domain->iommu);
	return nelems;
}

static struct dma_mapping_ops intel_dma_ops = {
	.alloc_coherent = intel_alloc_coherent,
	.free_coherent = intel_free_coherent,
	.map_single = intel_map_single,
	.unmap_single = intel_unmap_single,
	.map_sg = intel_map_sg,
	.unmap_sg = intel_unmap_sg,
};

static inline int iommu_domain_cache_init(void)
{
	int ret = 0;

	iommu_domain_cache = kmem_cache_create("iommu_domain",
					 sizeof(struct dmar_domain),
					 0,
					 SLAB_HWCACHE_ALIGN,

					 NULL);
	if (!iommu_domain_cache) {
		printk(KERN_ERR "Couldn't create iommu_domain cache\n");
		ret = -ENOMEM;
	}

	return ret;
}

static inline int iommu_devinfo_cache_init(void)
{
	int ret = 0;

	iommu_devinfo_cache = kmem_cache_create("iommu_devinfo",
					 sizeof(struct device_domain_info),
					 0,
					 SLAB_HWCACHE_ALIGN,

					 NULL);
	if (!iommu_devinfo_cache) {
		printk(KERN_ERR "Couldn't create devinfo cache\n");
		ret = -ENOMEM;
	}

	return ret;
}

static inline int iommu_iova_cache_init(void)
{
	int ret = 0;

	iommu_iova_cache = kmem_cache_create("iommu_iova",
					 sizeof(struct iova),
					 0,
					 SLAB_HWCACHE_ALIGN,

					 NULL);
	if (!iommu_iova_cache) {
		printk(KERN_ERR "Couldn't create iova cache\n");
		ret = -ENOMEM;
	}

	return ret;
}

static int __init iommu_init_mempool(void)
{
	int ret;
	ret = iommu_iova_cache_init();
	if (ret)
		return ret;

	ret = iommu_domain_cache_init();
	if (ret)
		goto domain_error;

	ret = iommu_devinfo_cache_init();
	if (!ret)
		return ret;

	kmem_cache_destroy(iommu_domain_cache);
domain_error:
	kmem_cache_destroy(iommu_iova_cache);

	return -ENOMEM;
}

static void __init iommu_exit_mempool(void)
{
	kmem_cache_destroy(iommu_devinfo_cache);
	kmem_cache_destroy(iommu_domain_cache);
	kmem_cache_destroy(iommu_iova_cache);

}

void __init detect_intel_iommu(void)
{
	if (swiotlb || no_iommu || iommu_detected || dmar_disabled)
		return;
	if (early_dmar_detect()) {
		iommu_detected = 1;
	}
}

static void __init init_no_remapping_devices(void)
{
	struct dmar_drhd_unit *drhd;

	for_each_drhd_unit(drhd) {
		if (!drhd->include_all) {
			int i;
			for (i = 0; i < drhd->devices_cnt; i++)
				if (drhd->devices[i] != NULL)
					break;
			/* ignore DMAR unit if no pci devices exist */
			if (i == drhd->devices_cnt)
				drhd->ignored = 1;
		}
	}

	if (dmar_map_gfx)
		return;

	for_each_drhd_unit(drhd) {
		int i;
		if (drhd->ignored || drhd->include_all)
			continue;

		for (i = 0; i < drhd->devices_cnt; i++)
			if (drhd->devices[i] &&
				!IS_GFX_DEVICE(drhd->devices[i]))
				break;

		if (i < drhd->devices_cnt)
			continue;

		/* bypass IOMMU if it is just for gfx devices */
		drhd->ignored = 1;
		for (i = 0; i < drhd->devices_cnt; i++) {
			if (!drhd->devices[i])
				continue;
			drhd->devices[i]->sysdata = DUMMY_DEVICE_DOMAIN_INFO;
		}
	}
}

int __init intel_iommu_init(void)
{
	int ret = 0;

	if (no_iommu || swiotlb || dmar_disabled)
		return -ENODEV;

	if (dmar_table_init())
		return 	-ENODEV;

	iommu_init_mempool();
	dmar_init_reserved_ranges();

	init_no_remapping_devices();

	ret = init_dmars();
	if (ret) {
		printk(KERN_ERR "IOMMU: dmar init failed\n");
		put_iova_domain(&reserved_iova_list);
		iommu_exit_mempool();
		return ret;
	}
	printk(KERN_INFO
	"PCI-DMA: Intel(R) Virtualization Technology for Directed I/O\n");

	force_iommu = 1;
	dma_ops = &intel_dma_ops;
	return 0;
}