/*
 * 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) 2006-2008 Intel Corporation
 * Author: Ashok Raj <ashok.raj@intel.com>
 * Author: Shaohua Li <shaohua.li@intel.com>
 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 * Author: Fenghua Yu <fenghua.yu@intel.com>
 */

#include <linux/init.h>
#include <linux/bitmap.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/dmar.h>
#include <linux/dma-mapping.h>
#include <linux/mempool.h>
#include <linux/timer.h>
#include <linux/iova.h>
#include <linux/iommu.h>
#include <linux/intel-iommu.h>
#include <linux/sysdev.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
#include "pci.h"

#define ROOT_SIZE               VTD_PAGE_SIZE
#define CONTEXT_SIZE            VTD_PAGE_SIZE

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

#define IOVA_PFN(addr)          ((addr) >> PAGE_SHIFT)
#define DMA_32BIT_PFN           IOVA_PFN(DMA_BIT_MASK(32))
#define DMA_64BIT_PFN           IOVA_PFN(DMA_BIT_MASK(64))

#ifndef PHYSICAL_PAGE_MASK
#define PHYSICAL_PAGE_MASK PAGE_MASK
#endif

/* global iommu list, set NULL for ignored DMAR units */
static struct intel_iommu **g_iommus;

static int rwbf_quirk;

/*
 * 0: Present
 * 1-11: Reserved
 * 12-63: Context Ptr (12 - (haw-1))
 * 64-127: Reserved
 */
struct root_entry {
        u64     val;
        u64     rsvd1;
};
#define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
static inline bool root_present(struct root_entry *root)
{
        return (root->val & 1);
}
static inline void set_root_present(struct root_entry *root)
{
        root->val |= 1;
}
static inline void set_root_value(struct root_entry *root, unsigned long value)
{
        root->val |= value & VTD_PAGE_MASK;
}

static inline struct context_entry *
get_context_addr_from_root(struct root_entry *root)
{
        return (struct context_entry *)
                (root_present(root)?phys_to_virt(
                root->val & VTD_PAGE_MASK) :
                NULL);
}

/*
 * low 64 bits:
 * 0: present
 * 1: fault processing disable
 * 2-3: translation type
 * 12-63: address space root
 * high 64 bits:
 * 0-2: address width
 * 3-6: aval
 * 8-23: domain id
 */
struct context_entry {
        u64 lo;
        u64 hi;
};

static inline bool context_present(struct context_entry *context)
{
        return (context->lo & 1);
}
static inline void context_set_present(struct context_entry *context)
{
        context->lo |= 1;
}

static inline void context_set_fault_enable(struct context_entry *context)
{
        context->lo &= (((u64)-1) << 2) | 1;
}

#define CONTEXT_TT_MULTI_LEVEL 0

static inline void context_set_translation_type(struct context_entry *context,
                                                unsigned long value)
{
        context->lo &= (((u64)-1) << 4) | 3;
        context->lo |= (value & 3) << 2;
}

static inline void context_set_address_root(struct context_entry *context,
                                            unsigned long value)
{
        context->lo |= value & VTD_PAGE_MASK;
}

static inline void context_set_address_width(struct context_entry *context,
                                             unsigned long value)
{
        context->hi |= value & 7;
}

static inline void context_set_domain_id(struct context_entry *context,
                                         unsigned long value)
{
        context->hi |= (value & ((1 << 16) - 1)) << 8;
}

static inline void context_clear_entry(struct context_entry *context)
{
        context->lo = 0;
        context->hi = 0;
}

/*
 * 0: readable
 * 1: writable
 * 2-6: reserved
 * 7: super page
 * 8-10: available
 * 11: snoop behavior
 * 12-63: Host physcial address
 */
struct dma_pte {
        u64 val;
};

static inline void dma_clear_pte(struct dma_pte *pte)
{
        pte->val = 0;
}

static inline void dma_set_pte_readable(struct dma_pte *pte)
{
        pte->val |= DMA_PTE_READ;
}

static inline void dma_set_pte_writable(struct dma_pte *pte)
{
        pte->val |= DMA_PTE_WRITE;
}

static inline void dma_set_pte_snp(struct dma_pte *pte)
{
        pte->val |= DMA_PTE_SNP;
}

static inline void dma_set_pte_prot(struct dma_pte *pte, unsigned long prot)
{
        pte->val = (pte->val & ~3) | (prot & 3);
}

static inline u64 dma_pte_addr(struct dma_pte *pte)
{
        return (pte->val & VTD_PAGE_MASK);
}

static inline void dma_set_pte_addr(struct dma_pte *pte, u64 addr)
{
        pte->val |= (addr & VTD_PAGE_MASK);
}

static inline bool dma_pte_present(struct dma_pte *pte)
{
        return (pte->val & 3) != 0;
}

/* devices under the same p2p bridge are owned in one domain */
#define DOMAIN_FLAG_P2P_MULTIPLE_DEVICES (1 << 0)

/* domain represents a virtual machine, more than one devices
 * across iommus may be owned in one domain, e.g. kvm guest.
 */
#define DOMAIN_FLAG_VIRTUAL_MACHINE     (1 << 1)

struct dmar_domain {
        int     id;                     /* domain id */
        unsigned long iommu_bmp;        /* bitmap of iommus this domain uses*/

        struct list_head devices;       /* all devices' list */
        struct iova_domain iovad;       /* iova's that belong to this domain */

        struct dma_pte  *pgd;           /* virtual address */
        spinlock_t      mapping_lock;   /* page table lock */
        int             gaw;            /* max guest address width */

        /* adjusted guest address width, 0 is level 2 30-bit */
        int             agaw;

        int             flags;          /* flags to find out type of domain */

        int             iommu_coherency;/* indicate coherency of iommu access */
        int             iommu_snooping; /* indicate snooping control feature*/
        int             iommu_count;    /* reference count of iommu */
        spinlock_t      iommu_lock;     /* protect iommu set in domain */
        u64             max_addr;       /* maximum mapped address */
};

/* PCI domain-device relationship */
struct device_domain_info {
        struct list_head link;  /* link to domain siblings */
        struct list_head global; /* link to global list */
        int segment;            /* PCI domain */
        u8 bus;                 /* PCI bus number */
        u8 devfn;               /* PCI devfn number */
        struct pci_dev *dev; /* it's NULL for PCIE-to-PCI bridge */
        struct dmar_domain *domain; /* pointer to domain */
};

static void flush_unmaps_timeout(unsigned long data);

DEFINE_TIMER(unmap_timer,  flush_unmaps_timeout, 0, 0);

#define HIGH_WATER_MARK 250
struct deferred_flush_tables {
        int next;
        struct iova *iova[HIGH_WATER_MARK];
        struct dmar_domain *domain[HIGH_WATER_MARK];
};

static struct deferred_flush_tables *deferred_flush;

/* bitmap for indexing intel_iommus */
static int g_num_of_iommus;

static DEFINE_SPINLOCK(async_umap_flush_lock);
static LIST_HEAD(unmaps_to_do);

static int timer_on;
static long list_size;

static void domain_remove_dev_info(struct dmar_domain *domain);

#ifdef CONFIG_DMAR_DEFAULT_ON
int dmar_disabled = 0;
#else
int dmar_disabled = 1;
#endif /*CONFIG_DMAR_DEFAULT_ON*/

static int __initdata dmar_map_gfx = 1;
static int dmar_forcedac;
static int intel_iommu_strict;

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

static struct iommu_ops intel_iommu_ops;

static int __init intel_iommu_setup(char *str)
{
        if (!str)
                return -EINVAL;
        while (*str) {
                if (!strncmp(str, "on", 2)) {
                        dmar_disabled = 0;
                        printk(KERN_INFO "Intel-IOMMU: enabled\n");
                } else 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");
                } else if (!strncmp(str, "forcedac", 8)) {
                        printk(KERN_INFO
                                "Intel-IOMMU: Forcing DAC for PCI devices\n");
                        dmar_forcedac = 1;
                } else if (!strncmp(str, "strict", 6)) {
                        printk(KERN_INFO
                                "Intel-IOMMU: disable batched IOTLB flush\n");
                        intel_iommu_strict = 1;
                }

                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 *iommu_kmem_cache_alloc(struct kmem_cache *cachep)
{
        unsigned int flags;
        void *vaddr;

        /* trying to avoid low memory issues */
        flags = current->flags & PF_MEMALLOC;
        current->flags |= PF_MEMALLOC;
        vaddr = kmem_cache_alloc(cachep, GFP_ATOMIC);
        current->flags &= (~PF_MEMALLOC | flags);
        return vaddr;
}


static inline void *alloc_pgtable_page(void)
{
        unsigned int flags;
        void *vaddr;

        /* trying to avoid low memory issues */
        flags = current->flags & PF_MEMALLOC;
        current->flags |= PF_MEMALLOC;
        vaddr = (void *)get_zeroed_page(GFP_ATOMIC);
        current->flags &= (~PF_MEMALLOC | flags);
        return vaddr;
}

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

static inline void *alloc_domain_mem(void)
{
        return iommu_kmem_cache_alloc(iommu_domain_cache);
}

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

static inline void * alloc_devinfo_mem(void)
{
        return iommu_kmem_cache_alloc(iommu_devinfo_cache);
}

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

struct iova *alloc_iova_mem(void)
{
        return iommu_kmem_cache_alloc(iommu_iova_cache);
}

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


static inline int width_to_agaw(int width);

/* calculate agaw for each iommu.
 * "SAGAW" may be different across iommus, use a default agaw, and
 * get a supported less agaw for iommus that don't support the default agaw.
 */
int iommu_calculate_agaw(struct intel_iommu *iommu)
{
        unsigned long sagaw;
        int agaw = -1;

        sagaw = cap_sagaw(iommu->cap);
        for (agaw = width_to_agaw(DEFAULT_DOMAIN_ADDRESS_WIDTH);
             agaw >= 0; agaw--) {
                if (test_bit(agaw, &sagaw))
                        break;
        }

        return agaw;
}

/* in native case, each domain is related to only one iommu */
static struct intel_iommu *domain_get_iommu(struct dmar_domain *domain)
{
        int iommu_id;

        BUG_ON(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE);

        iommu_id = find_first_bit(&domain->iommu_bmp, g_num_of_iommus);
        if (iommu_id < 0 || iommu_id >= g_num_of_iommus)
                return NULL;

        return g_iommus[iommu_id];
}

static void domain_update_iommu_coherency(struct dmar_domain *domain)
{
        int i;

        domain->iommu_coherency = 1;

        i = find_first_bit(&domain->iommu_bmp, g_num_of_iommus);
        for (; i < g_num_of_iommus; ) {
                if (!ecap_coherent(g_iommus[i]->ecap)) {
                        domain->iommu_coherency = 0;
                        break;
                }
                i = find_next_bit(&domain->iommu_bmp, g_num_of_iommus, i+1);
        }
}

static void domain_update_iommu_snooping(struct dmar_domain *domain)
{
        int i;

        domain->iommu_snooping = 1;

        i = find_first_bit(&domain->iommu_bmp, g_num_of_iommus);
        for (; i < g_num_of_iommus; ) {
                if (!ecap_sc_support(g_iommus[i]->ecap)) {
                        domain->iommu_snooping = 0;
                        break;
                }
                i = find_next_bit(&domain->iommu_bmp, g_num_of_iommus, i+1);
        }
}

/* Some capabilities may be different across iommus */
static void domain_update_iommu_cap(struct dmar_domain *domain)
{
        domain_update_iommu_coherency(domain);
        domain_update_iommu_snooping(domain);
}

static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
{
        struct dmar_drhd_unit *drhd = NULL;
        int i;

        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;
                if (segment != drhd->segment)
                        continue;

                for (i = 0; i < drhd->devices_cnt; i++) {
                        if (drhd->devices[i] &&
                            drhd->devices[i]->bus->number == bus &&
                            drhd->devices[i]->devfn == devfn)
                                return drhd->iommu;
                        if (drhd->devices[i] &&
                            drhd->devices[i]->subordinate &&
                            drhd->devices[i]->subordinate->number <= bus &&
                            drhd->devices[i]->subordinate->subordinate >= bus)
                                return drhd->iommu;
                }

                if (drhd->include_all)
                        return drhd->iommu;
        }

        return NULL;
}

static void domain_flush_cache(struct dmar_domain *domain,
                               void *addr, int size)
{
        if (!domain->iommu_coherency)
                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, CONTEXT_SIZE);
                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;
                        }
                        domain_flush_cache(domain, tmp_page, PAGE_SIZE);
                        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);
                        domain_flush_cache(domain, 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);
                domain_flush_cache(domain, 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);
        int npages;

        start &= (((u64)1) << addr_width) - 1;
        end &= (((u64)1) << addr_width) - 1;
        /* in case it's partial page */
        start &= PAGE_MASK;
        end = PAGE_ALIGN(end);
        npages = (end - start) / VTD_PAGE_SIZE;

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

/* 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);
                                domain_flush_cache(domain, 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, ROOT_SIZE);

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

        return 0;
}

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 (!rwbf_quirk && !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 implicitly flush write buffer */
        return 0;
}

/* 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",
                        (unsigned long long)DMA_TLB_IIRG(type),
                        (unsigned long long)DMA_TLB_IAIG(val));
        /* flush iotlb entry will implicitly flush write buffer */
        return 0;
}

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

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

        /* Fallback to domain selective flush if no PSI support */
        if (!cap_pgsel_inv(iommu->cap))
                return iommu->flush.flush_iotlb(iommu, did, 0, 0,
                                                DMA_TLB_DSI_FLUSH,
                                                non_present_entry_flush);

        /*
         * PSI requires page size to be 2 ^ x, and the base address is naturally
         * aligned to the size
         */
        mask = ilog2(__roundup_pow_of_two(pages));
        /* Fallback to domain selective flush if size is too big */
        if (mask > cap_max_amask_val(iommu->cap))
                return iommu->flush.flush_iotlb(iommu, did, 0, 0,
                        DMA_TLB_DSI_FLUSH, non_present_entry_flush);

        return iommu->flush.flush_iotlb(iommu, did, addr, mask,
                                        DMA_TLB_PSI_FLUSH,
                                        non_present_entry_flush);
}

static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
{
        u32 pmen;
        unsigned long flags;

        spin_lock_irqsave(&iommu->register_lock, flags);
        pmen = readl(iommu->reg + DMAR_PMEN_REG);
        pmen &= ~DMA_PMEN_EPM;
        writel(pmen, iommu->reg + DMAR_PMEN_REG);

        /* wait for the protected region status bit to clear */
        IOMMU_WAIT_OP(iommu, DMAR_PMEN_REG,
                readl, !(pmen & DMA_PMEN_PRS), pmen);

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

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;
        }

        spin_lock_init(&iommu->lock);

        /*
         * 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 void domain_exit(struct dmar_domain *domain);
static void vm_domain_exit(struct dmar_domain *domain);

void free_dmar_iommu(struct intel_iommu *iommu)
{
        struct dmar_domain *domain;
        int i;
        unsigned long flags;

        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);

                spin_lock_irqsave(&domain->iommu_lock, flags);
                if (--domain->iommu_count == 0) {
                        if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE)
                                vm_domain_exit(domain);
                        else
                                domain_exit(domain);
                }
                spin_unlock_irqrestore(&domain->iommu_lock, flags);

                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);

        g_iommus[iommu->seq_id] = NULL;

        /* if all iommus are freed, free g_iommus */
        for (i = 0; i < g_num_of_iommus; i++) {
                if (g_iommus[i])
                        break;
        }

        if (i == g_num_of_iommus)
                kfree(g_iommus);

        /* free context mapping */
        free_context_table(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;
        memset(&domain->iommu_bmp, 0, sizeof(unsigned long));
        set_bit(iommu->seq_id, &domain->iommu_bmp);
        domain->flags = 0;
        iommu->domains[num] = domain;
        spin_unlock_irqrestore(&iommu->lock, flags);

        return domain;
}

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

        iommu = domain_get_iommu(domain);

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

static struct iova_domain reserved_iova_list;
static struct lock_class_key reserved_alloc_key;
static struct lock_class_key reserved_rbtree_key;

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, DMA_32BIT_PFN);

        lockdep_set_class(&reserved_iova_list.iova_alloc_lock,
                &reserved_alloc_key);
        lockdep_set_class(&reserved_iova_list.iova_rbtree_lock,
                &reserved_rbtree_key);

        /* 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 &= PHYSICAL_PAGE_MASK;
                        size = r->end - addr;
                        size = PAGE_ALIGN(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, DMA_32BIT_PFN);
        spin_lock_init(&domain->mapping_lock);
        spin_lock_init(&domain->iommu_lock);

        domain_reserve_special_ranges(domain);

        /* calculate AGAW */
        iommu = domain_get_iommu(domain);
        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);

        if (ecap_coherent(iommu->ecap))
                domain->iommu_coherency = 1;
        else
                domain->iommu_coherency = 0;

        if (ecap_sc_support(iommu->ecap))
                domain->iommu_snooping = 1;
        else
                domain->iommu_snooping = 0;

        domain->iommu_count = 1;

        /* 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);
        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);

        /* 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,
                                      int segment, u8 bus, u8 devfn)
{
        struct context_entry *context;
        unsigned long flags;
        struct intel_iommu *iommu;
        struct dma_pte *pgd;
        unsigned long num;
        unsigned long ndomains;
        int id;
        int agaw;

        pr_debug("Set context mapping for %02x:%02x.%d\n",
                bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
        BUG_ON(!domain->pgd);

        iommu = device_to_iommu(segment, bus, devfn);
        if (!iommu)
                return -ENODEV;

        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;
        }

        id = domain->id;
        pgd = domain->pgd;

        if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) {
                int found = 0;

                /* find an available domain id for this device in iommu */
                ndomains = cap_ndoms(iommu->cap);
                num = find_first_bit(iommu->domain_ids, ndomains);
                for (; num < ndomains; ) {
                        if (iommu->domains[num] == domain) {
                                id = num;
                                found = 1;
                                break;
                        }
                        num = find_next_bit(iommu->domain_ids,
                                            cap_ndoms(iommu->cap), num+1);
                }

                if (found == 0) {
                        num = find_first_zero_bit(iommu->domain_ids, ndomains);
                        if (num >= ndomains) {
                                spin_unlock_irqrestore(&iommu->lock, flags);
                                printk(KERN_ERR "IOMMU: no free domain ids\n");
                                return -EFAULT;
                        }

                        set_bit(num, iommu->domain_ids);
                        iommu->domains[num] = domain;
                        id = num;
                }

                /* Skip top levels of page tables for
                 * iommu which has less agaw than default.
                 */
                for (agaw = domain->agaw; agaw != iommu->agaw; agaw--) {
                        pgd = phys_to_virt(dma_pte_addr(pgd));
                        if (!dma_pte_present(pgd)) {
                                spin_unlock_irqrestore(&iommu->lock, flags);
                                return -ENOMEM;
                        }
                }
        }

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

        /* it's a non-present to present mapping */
        if (iommu->flush.flush_context(iommu, domain->id,
                (((u16)bus) << 8) | devfn, DMA_CCMD_MASK_NOBIT,
                DMA_CCMD_DEVICE_INVL, 1))
                iommu_flush_write_buffer(iommu);
        else
                iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_DSI_FLUSH, 0);

        spin_unlock_irqrestore(&iommu->lock, flags);

        spin_lock_irqsave(&domain->iommu_lock, flags);
        if (!test_and_set_bit(iommu->seq_id, &domain->iommu_bmp)) {
                domain->iommu_count++;
                domain_update_iommu_cap(domain);
        }
        spin_unlock_irqrestore(&domain->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, pci_domain_nr(pdev->bus),
                                         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,
                                                 pci_domain_nr(parent->bus),
                                                 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,
                                        pci_domain_nr(tmp->subordinate),
                                        tmp->subordinate->number, 0);
        else /* this is a legacy PCI bridge */
                return domain_context_mapping_one(domain,
                                                  pci_domain_nr(tmp->bus),
                                                  tmp->bus->number,
                                                  tmp->devfn);
}

static int domain_context_mapped(struct pci_dev *pdev)
{
        int ret;
        struct pci_dev *tmp, *parent;
        struct intel_iommu *iommu;

        iommu = device_to_iommu(pci_domain_nr(pdev->bus), pdev->bus->number,
                                pdev->devfn);
        if (!iommu)
                return -ENODEV;

        ret = device_context_mapped(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(iommu, parent->bus->number,
                                            parent->devfn);
                if (!ret)
                        return ret;
                parent = parent->bus->self;
        }
        if (tmp->is_pcie)
                return device_context_mapped(iommu, tmp->subordinate->number,
                                             0);
        else
                return device_context_mapped(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;
        int addr_width = agaw_to_width(domain->agaw);

        hpa &= (((u64)1) << addr_width) - 1;

        if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
                return -EINVAL;
        iova &= PAGE_MASK;
        start_pfn = ((u64)hpa) >> VTD_PAGE_SHIFT;
        end_pfn = (VTD_PAGE_ALIGN(((u64)hpa) + size)) >> VTD_PAGE_SHIFT;
        index = 0;
        while (start_pfn < end_pfn) {
                pte = addr_to_dma_pte(domain, iova + VTD_PAGE_SIZE * 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 << VTD_PAGE_SHIFT);
                dma_set_pte_prot(pte, prot);
                if (prot & DMA_PTE_SNP)
                        dma_set_pte_snp(pte);
                domain_flush_cache(domain, pte, sizeof(*pte));
                start_pfn++;
                index++;
        }
        return 0;
}

static void iommu_detach_dev(struct intel_iommu *iommu, u8 bus, u8 devfn)
{
        if (!iommu)
                return;

        clear_context_table(iommu, bus, devfn);
        iommu->flush.flush_context(iommu, 0, 0, 0,
                                           DMA_CCMD_GLOBAL_INVL, 0);
        iommu->flush.flush_iotlb(iommu, 0, 0, 0,
                                         DMA_TLB_GLOBAL_FLUSH, 0);
}

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

        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->dev.archdata.iommu = NULL;
                spin_unlock_irqrestore(&device_domain_lock, flags);

                iommu = device_to_iommu(info->segment, info->bus, info->devfn);
                iommu_detach_dev(iommu, 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->dev.archdata.iommu stores the info
 */
static 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->dev.archdata.iommu;
        if (info)
                return info->domain;
        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;
        int segment;

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

        segment = pci_domain_nr(pdev->bus);

        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->segment == segment &&
                            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->segment = segment;
                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_P2P_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->segment == segment &&
                            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->segment = segment;
        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->dev.archdata.iommu = 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,
                                      unsigned long long start,
                                      unsigned long long end)
{
        struct dmar_domain *domain;
        unsigned long size;
        unsigned long long 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;
        size = end - base;
        size = PAGE_ALIGN(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->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO)
                return 0;
        return iommu_prepare_identity_map(pdev, rmrr->base_address,
                rmrr->end_address + 1);
}

#ifdef CONFIG_DMAR_GFX_WA
struct iommu_prepare_data {
        struct pci_dev *pdev;
        int ret;
};

static int __init iommu_prepare_work_fn(unsigned long start_pfn,
                                         unsigned long end_pfn, void *datax)
{
        struct iommu_prepare_data *data;

        data = (struct iommu_prepare_data *)datax;

        data->ret = iommu_prepare_identity_map(data->pdev,
                                start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
        return data->ret;

}

static int __init iommu_prepare_with_active_regions(struct pci_dev *pdev)
{
        int nid;
        struct iommu_prepare_data data;

        data.pdev = pdev;
        data.ret = 0;

        for_each_online_node(nid) {
                work_with_active_regions(nid, iommu_prepare_work_fn, &data);
                if (data.ret)
                        return data.ret;
        }
        return data.ret;
}

static void __init iommu_prepare_gfx_mapping(void)
{
        struct pci_dev *pdev = NULL;
        int ret;

        for_each_pci_dev(pdev) {
                if (pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO ||
                                !IS_GFX_DEVICE(pdev))
                        continue;
                printk(KERN_INFO "IOMMU: gfx device %s 1-1 mapping\n",
                        pci_name(pdev));
                ret = iommu_prepare_with_active_regions(pdev);
                if (ret)
                        printk(KERN_ERR "IOMMU: mapping reserved region failed\n");
        }
}
#else /* !CONFIG_DMAR_GFX_WA */
static inline void iommu_prepare_gfx_mapping(void)
{
        return;
}
#endif

#ifdef CONFIG_DMAR_FLOPPY_WA
static inline void iommu_prepare_isa(void)
{
        struct pci_dev *pdev;
        int ret;

        pdev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
        if (!pdev)
                return;

        printk(KERN_INFO "IOMMU: Prepare 0-16M unity mapping for LPC\n");
        ret = iommu_prepare_identity_map(pdev, 0, 16*1024*1024);

        if (ret)
                printk(KERN_ERR "IOMMU: Failed to create 0-64M identity map, "
                        "floppy might not work\n");

}
#else
static inline void iommu_prepare_isa(void)
{
        return;
}
#endif /* !CONFIG_DMAR_FLPY_WA */

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

        /*
         * for each drhd
         *    allocate root
         *    initialize and program root entry to not present
         * endfor
         */
        for_each_drhd_unit(drhd) {
                g_num_of_iommus++;
                /*
                 * lock not needed as this is only incremented in the single
                 * threaded kernel __init code path all other access are read
                 * only
                 */
        }

        g_iommus = kcalloc(g_num_of_iommus, sizeof(struct intel_iommu *),
                        GFP_KERNEL);
        if (!g_iommus) {
                printk(KERN_ERR "Allocating global iommu array failed\n");
                ret = -ENOMEM;
                goto error;
        }

        deferred_flush = kzalloc(g_num_of_iommus *
                sizeof(struct deferred_flush_tables), GFP_KERNEL);
        if (!deferred_flush) {
                kfree(g_iommus);
                ret = -ENOMEM;
                goto error;
        }

        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;

                iommu = drhd->iommu;
                g_iommus[iommu->seq_id] = iommu;

                ret = iommu_init_domains(iommu);
                if (ret)
                        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;
                }
        }

        /*
         * Start from the sane iommu hardware state.
         */
        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;

                iommu = drhd->iommu;

                /*
                 * If the queued invalidation is already initialized by us
                 * (for example, while enabling interrupt-remapping) then
                 * we got the things already rolling from a sane state.
                 */
                if (iommu->qi)
                        continue;

                /*
                 * Clear any previous faults.
                 */
                dmar_fault(-1, iommu);
                /*
                 * Disable queued invalidation if supported and already enabled
                 * before OS handover.
                 */
                dmar_disable_qi(iommu);
        }

        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;

                iommu = drhd->iommu;

                if (dmar_enable_qi(iommu)) {
                        /*
                         * Queued Invalidate not enabled, use Register Based
                         * Invalidate
                         */
                        iommu->flush.flush_context = __iommu_flush_context;
                        iommu->flush.flush_iotlb = __iommu_flush_iotlb;
                        printk(KERN_INFO "IOMMU 0x%Lx: using Register based "
                               "invalidation\n",
                               (unsigned long long)drhd->reg_base_addr);
                } else {
                        iommu->flush.flush_context = qi_flush_context;
                        iommu->flush.flush_iotlb = qi_flush_iotlb;
                        printk(KERN_INFO "IOMMU 0x%Lx: using Queued "
                               "invalidation\n",
                               (unsigned long long)drhd->reg_base_addr);
                }
        }

#ifdef CONFIG_INTR_REMAP
        if (!intr_remapping_enabled) {
                ret = enable_intr_remapping(0);
                if (ret)
                        printk(KERN_ERR
                               "IOMMU: enable interrupt remapping failed\n");
        }
#endif

        /*
         * 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) {
                for (i = 0; i < rmrr->devices_cnt; i++) {
                        pdev = rmrr->devices[i];