/*
 *      Intel IO-APIC support for multi-Pentium hosts.
 *
 *      Copyright (C) 1997, 1998, 1999, 2000, 2009 Ingo Molnar, Hajnalka Szabo
 *
 *      Many thanks to Stig Venaas for trying out countless experimental
 *      patches and reporting/debugging problems patiently!
 *
 *      (c) 1999, Multiple IO-APIC support, developed by
 *      Ken-ichi Yaku <yaku@css1.kbnes.nec.co.jp> and
 *      Hidemi Kishimoto <kisimoto@css1.kbnes.nec.co.jp>,
 *      further tested and cleaned up by Zach Brown <zab@redhat.com>
 *      and Ingo Molnar <mingo@redhat.com>
 *
 *      Fixes
 *      Maciej W. Rozycki       :       Bits for genuine 82489DX APICs;
 *                                      thanks to Eric Gilmore
 *                                      and Rolf G. Tews
 *                                      for testing these extensively
 *      Paul Diefenbaugh        :       Added full ACPI support
 */

#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/mc146818rtc.h>
#include <linux/compiler.h>
#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/syscore_ops.h>
#include <linux/msi.h>
#include <linux/htirq.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/jiffies.h>      /* time_after() */
#include <linux/slab.h>
#ifdef CONFIG_ACPI
#include <acpi/acpi_bus.h>
#endif
#include <linux/bootmem.h>
#include <linux/dmar.h>
#include <linux/hpet.h>

#include <asm/idle.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/cpu.h>
#include <asm/desc.h>
#include <asm/proto.h>
#include <asm/acpi.h>
#include <asm/dma.h>
#include <asm/timer.h>
#include <asm/i8259.h>
#include <asm/msidef.h>
#include <asm/hypertransport.h>
#include <asm/setup.h>
#include <asm/irq_remapping.h>
#include <asm/hpet.h>
#include <asm/hw_irq.h>

#include <asm/apic.h>

#define __apicdebuginit(type) static type __init

#define for_each_irq_pin(entry, head) \
        for (entry = head; entry; entry = entry->next)

/*
 *      Is the SiS APIC rmw bug present ?
 *      -1 = don't know, 0 = no, 1 = yes
 */
int sis_apic_bug = -1;

static DEFINE_RAW_SPINLOCK(ioapic_lock);
static DEFINE_RAW_SPINLOCK(vector_lock);

static struct ioapic {
        /*
         * # of IRQ routing registers
         */
        int nr_registers;
        /*
         * Saved state during suspend/resume, or while enabling intr-remap.
         */
        struct IO_APIC_route_entry *saved_registers;
        /* I/O APIC config */
        struct mpc_ioapic mp_config;
        /* IO APIC gsi routing info */
        struct mp_ioapic_gsi  gsi_config;
        DECLARE_BITMAP(pin_programmed, MP_MAX_IOAPIC_PIN + 1);
} ioapics[MAX_IO_APICS];

#define mpc_ioapic_ver(ioapic_idx)      ioapics[ioapic_idx].mp_config.apicver

int mpc_ioapic_id(int ioapic_idx)
{
        return ioapics[ioapic_idx].mp_config.apicid;
}

unsigned int mpc_ioapic_addr(int ioapic_idx)
{
        return ioapics[ioapic_idx].mp_config.apicaddr;
}

struct mp_ioapic_gsi *mp_ioapic_gsi_routing(int ioapic_idx)
{
        return &ioapics[ioapic_idx].gsi_config;
}

int nr_ioapics;

/* The one past the highest gsi number used */
u32 gsi_top;

/* MP IRQ source entries */
struct mpc_intsrc mp_irqs[MAX_IRQ_SOURCES];

/* # of MP IRQ source entries */
int mp_irq_entries;

/* GSI interrupts */
static int nr_irqs_gsi = NR_IRQS_LEGACY;

#ifdef CONFIG_EISA
int mp_bus_id_to_type[MAX_MP_BUSSES];
#endif

DECLARE_BITMAP(mp_bus_not_pci, MAX_MP_BUSSES);

int skip_ioapic_setup;

/**
 * disable_ioapic_support() - disables ioapic support at runtime
 */
void disable_ioapic_support(void)
{
#ifdef CONFIG_PCI
        noioapicquirk = 1;
        noioapicreroute = -1;
#endif
        skip_ioapic_setup = 1;
}

static int __init parse_noapic(char *str)
{
        /* disable IO-APIC */
        disable_ioapic_support();
        return 0;
}
early_param("noapic", parse_noapic);

static int io_apic_setup_irq_pin(unsigned int irq, int node,
                                 struct io_apic_irq_attr *attr);

/* Will be called in mpparse/acpi/sfi codes for saving IRQ info */
void mp_save_irq(struct mpc_intsrc *m)
{
        int i;

        apic_printk(APIC_VERBOSE, "Int: type %d, pol %d, trig %d, bus %02x,"
                " IRQ %02x, APIC ID %x, APIC INT %02x\n",
                m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbus,
                m->srcbusirq, m->dstapic, m->dstirq);

        for (i = 0; i < mp_irq_entries; i++) {
                if (!memcmp(&mp_irqs[i], m, sizeof(*m)))
                        return;
        }

        memcpy(&mp_irqs[mp_irq_entries], m, sizeof(*m));
        if (++mp_irq_entries == MAX_IRQ_SOURCES)
                panic("Max # of irq sources exceeded!!\n");
}

struct irq_pin_list {
        int apic, pin;
        struct irq_pin_list *next;
};

static struct irq_pin_list *alloc_irq_pin_list(int node)
{
        return kzalloc_node(sizeof(struct irq_pin_list), GFP_KERNEL, node);
}


/* irq_cfg is indexed by the sum of all RTEs in all I/O APICs. */
static struct irq_cfg irq_cfgx[NR_IRQS_LEGACY];

int __init arch_early_irq_init(void)
{
        struct irq_cfg *cfg;
        int count, node, i;

        if (!legacy_pic->nr_legacy_irqs)
                io_apic_irqs = ~0UL;

        for (i = 0; i < nr_ioapics; i++) {
                ioapics[i].saved_registers =
                        kzalloc(sizeof(struct IO_APIC_route_entry) *
                                ioapics[i].nr_registers, GFP_KERNEL);
                if (!ioapics[i].saved_registers)
                        pr_err("IOAPIC %d: suspend/resume impossible!\n", i);
        }

        cfg = irq_cfgx;
        count = ARRAY_SIZE(irq_cfgx);
        node = cpu_to_node(0);

        /* Make sure the legacy interrupts are marked in the bitmap */
        irq_reserve_irqs(0, legacy_pic->nr_legacy_irqs);

        for (i = 0; i < count; i++) {
                irq_set_chip_data(i, &cfg[i]);
                zalloc_cpumask_var_node(&cfg[i].domain, GFP_KERNEL, node);
                zalloc_cpumask_var_node(&cfg[i].old_domain, GFP_KERNEL, node);
                /*
                 * For legacy IRQ's, start with assigning irq0 to irq15 to
                 * IRQ0_VECTOR to IRQ15_VECTOR for all cpu's.
                 */
                if (i < legacy_pic->nr_legacy_irqs) {
                        cfg[i].vector = IRQ0_VECTOR + i;
                        cpumask_setall(cfg[i].domain);
                }
        }

        return 0;
}

static struct irq_cfg *irq_cfg(unsigned int irq)
{
        return irq_get_chip_data(irq);
}

static struct irq_cfg *alloc_irq_cfg(unsigned int irq, int node)
{
        struct irq_cfg *cfg;

        cfg = kzalloc_node(sizeof(*cfg), GFP_KERNEL, node);
        if (!cfg)
                return NULL;
        if (!zalloc_cpumask_var_node(&cfg->domain, GFP_KERNEL, node))
                goto out_cfg;
        if (!zalloc_cpumask_var_node(&cfg->old_domain, GFP_KERNEL, node))
                goto out_domain;
        return cfg;
out_domain:
        free_cpumask_var(cfg->domain);
out_cfg:
        kfree(cfg);
        return NULL;
}

static void free_irq_cfg(unsigned int at, struct irq_cfg *cfg)
{
        if (!cfg)
                return;
        irq_set_chip_data(at, NULL);
        free_cpumask_var(cfg->domain);
        free_cpumask_var(cfg->old_domain);
        kfree(cfg);
}

static struct irq_cfg *alloc_irq_and_cfg_at(unsigned int at, int node)
{
        int res = irq_alloc_desc_at(at, node);
        struct irq_cfg *cfg;

        if (res < 0) {
                if (res != -EEXIST)
                        return NULL;
                cfg = irq_get_chip_data(at);
                if (cfg)
                        return cfg;
        }

        cfg = alloc_irq_cfg(at, node);
        if (cfg)
                irq_set_chip_data(at, cfg);
        else
                irq_free_desc(at);
        return cfg;
}

static int alloc_irqs_from(unsigned int from, unsigned int count, int node)
{
        return irq_alloc_descs_from(from, count, node);
}

static void free_irq_at(unsigned int at, struct irq_cfg *cfg)
{
        free_irq_cfg(at, cfg);
        irq_free_desc(at);
}


struct io_apic {
        unsigned int index;
        unsigned int unused[3];
        unsigned int data;
        unsigned int unused2[11];
        unsigned int eoi;
};

static __attribute_const__ struct io_apic __iomem *io_apic_base(int idx)
{
        return (void __iomem *) __fix_to_virt(FIX_IO_APIC_BASE_0 + idx)
                + (mpc_ioapic_addr(idx) & ~PAGE_MASK);
}

void io_apic_eoi(unsigned int apic, unsigned int vector)
{
        struct io_apic __iomem *io_apic = io_apic_base(apic);
        writel(vector, &io_apic->eoi);
}

unsigned int native_io_apic_read(unsigned int apic, unsigned int reg)
{
        struct io_apic __iomem *io_apic = io_apic_base(apic);
        writel(reg, &io_apic->index);
        return readl(&io_apic->data);
}

void native_io_apic_write(unsigned int apic, unsigned int reg, unsigned int value)
{
        struct io_apic __iomem *io_apic = io_apic_base(apic);

        writel(reg, &io_apic->index);
        writel(value, &io_apic->data);
}

/*
 * Re-write a value: to be used for read-modify-write
 * cycles where the read already set up the index register.
 *
 * Older SiS APIC requires we rewrite the index register
 */
void native_io_apic_modify(unsigned int apic, unsigned int reg, unsigned int value)
{
        struct io_apic __iomem *io_apic = io_apic_base(apic);

        if (sis_apic_bug)
                writel(reg, &io_apic->index);
        writel(value, &io_apic->data);
}

union entry_union {
        struct { u32 w1, w2; };
        struct IO_APIC_route_entry entry;
};

static struct IO_APIC_route_entry __ioapic_read_entry(int apic, int pin)
{
        union entry_union eu;

        eu.w1 = io_apic_read(apic, 0x10 + 2 * pin);
        eu.w2 = io_apic_read(apic, 0x11 + 2 * pin);

        return eu.entry;
}

static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin)
{
        union entry_union eu;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        eu.entry = __ioapic_read_entry(apic, pin);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        return eu.entry;
}

/*
 * When we write a new IO APIC routing entry, we need to write the high
 * word first! If the mask bit in the low word is clear, we will enable
 * the interrupt, and we need to make sure the entry is fully populated
 * before that happens.
 */
static void __ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
{
        union entry_union eu = {{0, 0}};

        eu.entry = e;
        io_apic_write(apic, 0x11 + 2*pin, eu.w2);
        io_apic_write(apic, 0x10 + 2*pin, eu.w1);
}

static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        __ioapic_write_entry(apic, pin, e);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

/*
 * When we mask an IO APIC routing entry, we need to write the low
 * word first, in order to set the mask bit before we change the
 * high bits!
 */
static void ioapic_mask_entry(int apic, int pin)
{
        unsigned long flags;
        union entry_union eu = { .entry.mask = 1 };

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        io_apic_write(apic, 0x10 + 2*pin, eu.w1);
        io_apic_write(apic, 0x11 + 2*pin, eu.w2);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

/*
 * The common case is 1:1 IRQ<->pin mappings. Sometimes there are
 * shared ISA-space IRQs, so we have to support them. We are super
 * fast in the common case, and fast for shared ISA-space IRQs.
 */
static int __add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pin)
{
        struct irq_pin_list **last, *entry;

        /* don't allow duplicates */
        last = &cfg->irq_2_pin;
        for_each_irq_pin(entry, cfg->irq_2_pin) {
                if (entry->apic == apic && entry->pin == pin)
                        return 0;
                last = &entry->next;
        }

        entry = alloc_irq_pin_list(node);
        if (!entry) {
                pr_err("can not alloc irq_pin_list (%d,%d,%d)\n",
                       node, apic, pin);
                return -ENOMEM;
        }
        entry->apic = apic;
        entry->pin = pin;

        *last = entry;
        return 0;
}

static void add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pin)
{
        if (__add_pin_to_irq_node(cfg, node, apic, pin))
                panic("IO-APIC: failed to add irq-pin. Can not proceed\n");
}

/*
 * Reroute an IRQ to a different pin.
 */
static void __init replace_pin_at_irq_node(struct irq_cfg *cfg, int node,
                                           int oldapic, int oldpin,
                                           int newapic, int newpin)
{
        struct irq_pin_list *entry;

        for_each_irq_pin(entry, cfg->irq_2_pin) {
                if (entry->apic == oldapic && entry->pin == oldpin) {
                        entry->apic = newapic;
                        entry->pin = newpin;
                        /* every one is different, right? */
                        return;
                }
        }

        /* old apic/pin didn't exist, so just add new ones */
        add_pin_to_irq_node(cfg, node, newapic, newpin);
}

static void __io_apic_modify_irq(struct irq_pin_list *entry,
                                 int mask_and, int mask_or,
                                 void (*final)(struct irq_pin_list *entry))
{
        unsigned int reg, pin;

        pin = entry->pin;
        reg = io_apic_read(entry->apic, 0x10 + pin * 2);
        reg &= mask_and;
        reg |= mask_or;
        io_apic_modify(entry->apic, 0x10 + pin * 2, reg);
        if (final)
                final(entry);
}

static void io_apic_modify_irq(struct irq_cfg *cfg,
                               int mask_and, int mask_or,
                               void (*final)(struct irq_pin_list *entry))
{
        struct irq_pin_list *entry;

        for_each_irq_pin(entry, cfg->irq_2_pin)
                __io_apic_modify_irq(entry, mask_and, mask_or, final);
}

static void io_apic_sync(struct irq_pin_list *entry)
{
        /*
         * Synchronize the IO-APIC and the CPU by doing
         * a dummy read from the IO-APIC
         */
        struct io_apic __iomem *io_apic;

        io_apic = io_apic_base(entry->apic);
        readl(&io_apic->data);
}

static void mask_ioapic(struct irq_cfg *cfg)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        io_apic_modify_irq(cfg, ~0, IO_APIC_REDIR_MASKED, &io_apic_sync);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

static void mask_ioapic_irq(struct irq_data *data)
{
        mask_ioapic(data->chip_data);
}

static void __unmask_ioapic(struct irq_cfg *cfg)
{
        io_apic_modify_irq(cfg, ~IO_APIC_REDIR_MASKED, 0, NULL);
}

static void unmask_ioapic(struct irq_cfg *cfg)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        __unmask_ioapic(cfg);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

static void unmask_ioapic_irq(struct irq_data *data)
{
        unmask_ioapic(data->chip_data);
}

/*
 * IO-APIC versions below 0x20 don't support EOI register.
 * For the record, here is the information about various versions:
 *     0Xh     82489DX
 *     1Xh     I/OAPIC or I/O(x)APIC which are not PCI 2.2 Compliant
 *     2Xh     I/O(x)APIC which is PCI 2.2 Compliant
 *     30h-FFh Reserved
 *
 * Some of the Intel ICH Specs (ICH2 to ICH5) documents the io-apic
 * version as 0x2. This is an error with documentation and these ICH chips
 * use io-apic's of version 0x20.
 *
 * For IO-APIC's with EOI register, we use that to do an explicit EOI.
 * Otherwise, we simulate the EOI message manually by changing the trigger
 * mode to edge and then back to level, with RTE being masked during this.
 */
void native_eoi_ioapic_pin(int apic, int pin, int vector)
{
        if (mpc_ioapic_ver(apic) >= 0x20) {
                io_apic_eoi(apic, vector);
        } else {
                struct IO_APIC_route_entry entry, entry1;

                entry = entry1 = __ioapic_read_entry(apic, pin);

                /*
                 * Mask the entry and change the trigger mode to edge.
                 */
                entry1.mask = 1;
                entry1.trigger = IOAPIC_EDGE;

                __ioapic_write_entry(apic, pin, entry1);

                /*
                 * Restore the previous level triggered entry.
                 */
                __ioapic_write_entry(apic, pin, entry);
        }
}

void eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)
{
        struct irq_pin_list *entry;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        for_each_irq_pin(entry, cfg->irq_2_pin)
                x86_io_apic_ops.eoi_ioapic_pin(entry->apic, entry->pin,
                                               cfg->vector);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

static void clear_IO_APIC_pin(unsigned int apic, unsigned int pin)
{
        struct IO_APIC_route_entry entry;

        /* Check delivery_mode to be sure we're not clearing an SMI pin */
        entry = ioapic_read_entry(apic, pin);
        if (entry.delivery_mode == dest_SMI)
                return;

        /*
         * Make sure the entry is masked and re-read the contents to check
         * if it is a level triggered pin and if the remote-IRR is set.
         */
        if (!entry.mask) {
                entry.mask = 1;
                ioapic_write_entry(apic, pin, entry);
                entry = ioapic_read_entry(apic, pin);
        }

        if (entry.irr) {
                unsigned long flags;

                /*
                 * Make sure the trigger mode is set to level. Explicit EOI
                 * doesn't clear the remote-IRR if the trigger mode is not
                 * set to level.
                 */
                if (!entry.trigger) {
                        entry.trigger = IOAPIC_LEVEL;
                        ioapic_write_entry(apic, pin, entry);
                }

                raw_spin_lock_irqsave(&ioapic_lock, flags);
                x86_io_apic_ops.eoi_ioapic_pin(apic, pin, entry.vector);
                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
        }

        /*
         * Clear the rest of the bits in the IO-APIC RTE except for the mask
         * bit.
         */
        ioapic_mask_entry(apic, pin);
        entry = ioapic_read_entry(apic, pin);
        if (entry.irr)
                pr_err("Unable to reset IRR for apic: %d, pin :%d\n",
                       mpc_ioapic_id(apic), pin);
}

static void clear_IO_APIC (void)
{
        int apic, pin;

        for (apic = 0; apic < nr_ioapics; apic++)
                for (pin = 0; pin < ioapics[apic].nr_registers; pin++)
                        clear_IO_APIC_pin(apic, pin);
}

#ifdef CONFIG_X86_32
/*
 * support for broken MP BIOSs, enables hand-redirection of PIRQ0-7 to
 * specific CPU-side IRQs.
 */

#define MAX_PIRQS 8
static int pirq_entries[MAX_PIRQS] = {
        [0 ... MAX_PIRQS - 1] = -1
};

static int __init ioapic_pirq_setup(char *str)
{
        int i, max;
        int ints[MAX_PIRQS+1];

        get_options(str, ARRAY_SIZE(ints), ints);

        apic_printk(APIC_VERBOSE, KERN_INFO
                        "PIRQ redirection, working around broken MP-BIOS.\n");
        max = MAX_PIRQS;
        if (ints[0] < MAX_PIRQS)
                max = ints[0];

        for (i = 0; i < max; i++) {
                apic_printk(APIC_VERBOSE, KERN_DEBUG
                                "... PIRQ%d -> IRQ %d\n", i, ints[i+1]);
                /*
                 * PIRQs are mapped upside down, usually.
                 */
                pirq_entries[MAX_PIRQS-i-1] = ints[i+1];
        }
        return 1;
}

__setup("pirq=", ioapic_pirq_setup);
#endif /* CONFIG_X86_32 */

/*
 * Saves all the IO-APIC RTE's
 */
int save_ioapic_entries(void)
{
        int apic, pin;
        int err = 0;

        for (apic = 0; apic < nr_ioapics; apic++) {
                if (!ioapics[apic].saved_registers) {
                        err = -ENOMEM;
                        continue;
                }

                for (pin = 0; pin < ioapics[apic].nr_registers; pin++)
                        ioapics[apic].saved_registers[pin] =
                                ioapic_read_entry(apic, pin);
        }

        return err;
}

/*
 * Mask all IO APIC entries.
 */
void mask_ioapic_entries(void)
{
        int apic, pin;

        for (apic = 0; apic < nr_ioapics; apic++) {
                if (!ioapics[apic].saved_registers)
                        continue;

                for (pin = 0; pin < ioapics[apic].nr_registers; pin++) {
                        struct IO_APIC_route_entry entry;

                        entry = ioapics[apic].saved_registers[pin];
                        if (!entry.mask) {
                                entry.mask = 1;
                                ioapic_write_entry(apic, pin, entry);
                        }
                }
        }
}

/*
 * Restore IO APIC entries which was saved in the ioapic structure.
 */
int restore_ioapic_entries(void)
{
        int apic, pin;

        for (apic = 0; apic < nr_ioapics; apic++) {
                if (!ioapics[apic].saved_registers)
                        continue;

                for (pin = 0; pin < ioapics[apic].nr_registers; pin++)
                        ioapic_write_entry(apic, pin,
                                           ioapics[apic].saved_registers[pin]);
        }
        return 0;
}

/*
 * Find the IRQ entry number of a certain pin.
 */
static int find_irq_entry(int ioapic_idx, int pin, int type)
{
        int i;

        for (i = 0; i < mp_irq_entries; i++)
                if (mp_irqs[i].irqtype == type &&
                    (mp_irqs[i].dstapic == mpc_ioapic_id(ioapic_idx) ||
                     mp_irqs[i].dstapic == MP_APIC_ALL) &&
                    mp_irqs[i].dstirq == pin)
                        return i;

        return -1;
}

/*
 * Find the pin to which IRQ[irq] (ISA) is connected
 */
static int __init find_isa_irq_pin(int irq, int type)
{
        int i;

        for (i = 0; i < mp_irq_entries; i++) {
                int lbus = mp_irqs[i].srcbus;

                if (test_bit(lbus, mp_bus_not_pci) &&
                    (mp_irqs[i].irqtype == type) &&
                    (mp_irqs[i].srcbusirq == irq))

                        return mp_irqs[i].dstirq;
        }
        return -1;
}

static int __init find_isa_irq_apic(int irq, int type)
{
        int i;

        for (i = 0; i < mp_irq_entries; i++) {
                int lbus = mp_irqs[i].srcbus;

                if (test_bit(lbus, mp_bus_not_pci) &&
                    (mp_irqs[i].irqtype == type) &&
                    (mp_irqs[i].srcbusirq == irq))
                        break;
        }

        if (i < mp_irq_entries) {
                int ioapic_idx;

                for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++)
                        if (mpc_ioapic_id(ioapic_idx) == mp_irqs[i].dstapic)
                                return ioapic_idx;
        }

        return -1;
}

#ifdef CONFIG_EISA
/*
 * EISA Edge/Level control register, ELCR
 */
static int EISA_ELCR(unsigned int irq)
{
        if (irq < legacy_pic->nr_legacy_irqs) {
                unsigned int port = 0x4d0 + (irq >> 3);
                return (inb(port) >> (irq & 7)) & 1;
        }
        apic_printk(APIC_VERBOSE, KERN_INFO
                        "Broken MPtable reports ISA irq %d\n", irq);
        return 0;
}

#endif

/* ISA interrupts are always polarity zero edge triggered,
 * when listed as conforming in the MP table. */

#define default_ISA_trigger(idx)        (0)
#define default_ISA_polarity(idx)       (0)

/* EISA interrupts are always polarity zero and can be edge or level
 * trigger depending on the ELCR value.  If an interrupt is listed as
 * EISA conforming in the MP table, that means its trigger type must
 * be read in from the ELCR */

#define default_EISA_trigger(idx)       (EISA_ELCR(mp_irqs[idx].srcbusirq))
#define default_EISA_polarity(idx)      default_ISA_polarity(idx)

/* PCI interrupts are always polarity one level triggered,
 * when listed as conforming in the MP table. */

#define default_PCI_trigger(idx)        (1)
#define default_PCI_polarity(idx)       (1)

static int irq_polarity(int idx)
{
        int bus = mp_irqs[idx].srcbus;
        int polarity;

        /*
         * Determine IRQ line polarity (high active or low active):
         */
        switch (mp_irqs[idx].irqflag & 3)
        {
                case 0: /* conforms, ie. bus-type dependent polarity */
                        if (test_bit(bus, mp_bus_not_pci))
                                polarity = default_ISA_polarity(idx);
                        else
                                polarity = default_PCI_polarity(idx);
                        break;
                case 1: /* high active */
                {
                        polarity = 0;
                        break;
                }
                case 2: /* reserved */
                {
                        pr_warn("broken BIOS!!\n");
                        polarity = 1;
                        break;
                }
                case 3: /* low active */
                {
                        polarity = 1;
                        break;
                }
                default: /* invalid */
                {
                        pr_warn("broken BIOS!!\n");
                        polarity = 1;
                        break;
                }
        }
        return polarity;
}

static int irq_trigger(int idx)
{
        int bus = mp_irqs[idx].srcbus;
        int trigger;

        /*
         * Determine IRQ trigger mode (edge or level sensitive):
         */
        switch ((mp_irqs[idx].irqflag>>2) & 3)
        {
                case 0: /* conforms, ie. bus-type dependent */
                        if (test_bit(bus, mp_bus_not_pci))
                                trigger = default_ISA_trigger(idx);
                        else
                                trigger = default_PCI_trigger(idx);
#ifdef CONFIG_EISA
                        switch (mp_bus_id_to_type[bus]) {
                                case MP_BUS_ISA: /* ISA pin */
                                {
                                        /* set before the switch */
                                        break;
                                }
                                case MP_BUS_EISA: /* EISA pin */
                                {
                                        trigger = default_EISA_trigger(idx);
                                        break;
                                }
                                case MP_BUS_PCI: /* PCI pin */
                                {
                                        /* set before the switch */
                                        break;
                                }
                                default:
                                {
                                        pr_warn("broken BIOS!!\n");
                                        trigger = 1;
                                        break;
                                }
                        }
#endif
                        break;
                case 1: /* edge */
                {
                        trigger = 0;
                        break;
                }
                case 2: /* reserved */
                {
                        pr_warn("broken BIOS!!\n");
                        trigger = 1;
                        break;
                }
                case 3: /* level */
                {
                        trigger = 1;
                        break;
                }
                default: /* invalid */
                {
                        pr_warn("broken BIOS!!\n");
                        trigger = 0;
                        break;
                }
        }
        return trigger;
}

static int pin_2_irq(int idx, int apic, int pin)
{
        int irq;
        int bus = mp_irqs[idx].srcbus;
        struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(apic);

        /*
         * Debugging check, we are in big trouble if this message pops up!
         */
        if (mp_irqs[idx].dstirq != pin)
                pr_err("broken BIOS or MPTABLE parser, ayiee!!\n");

        if (test_bit(bus, mp_bus_not_pci)) {
                irq = mp_irqs[idx].srcbusirq;
        } else {
                u32 gsi = gsi_cfg->gsi_base + pin;

                if (gsi >= NR_IRQS_LEGACY)
                        irq = gsi;
                else
                        irq = gsi_top + gsi;
        }

#ifdef CONFIG_X86_32
        /*
         * PCI IRQ command line redirection. Yes, limits are hardcoded.
         */
        if ((pin >= 16) && (pin <= 23)) {
                if (pirq_entries[pin-16] != -1) {
                        if (!pirq_entries[pin-16]) {
                                apic_printk(APIC_VERBOSE, KERN_DEBUG
                                                "disabling PIRQ%d\n", pin-16);
                        } else {
                                irq = pirq_entries[pin-16];
                                apic_printk(APIC_VERBOSE, KERN_DEBUG
                                                "using PIRQ%d -> IRQ %d\n",
                                                pin-16, irq);
                        }
                }
        }
#endif

        return irq;
}

/*
 * Find a specific PCI IRQ entry.
 * Not an __init, possibly needed by modules
 */
int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin,
                                struct io_apic_irq_attr *irq_attr)
{
        int ioapic_idx, i, best_guess = -1;

        apic_printk(APIC_DEBUG,
                    "querying PCI -> IRQ mapping bus:%d, slot:%d, pin:%d.\n",
                    bus, slot, pin);
        if (test_bit(bus, mp_bus_not_pci)) {
                apic_printk(APIC_VERBOSE,
                            "PCI BIOS passed nonexistent PCI bus %d!\n", bus);
                return -1;
        }
        for (i = 0; i < mp_irq_entries; i++) {
                int lbus = mp_irqs[i].srcbus;

                for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++)
                        if (mpc_ioapic_id(ioapic_idx) == mp_irqs[i].dstapic ||
                            mp_irqs[i].dstapic == MP_APIC_ALL)
                                break;

                if (!test_bit(lbus, mp_bus_not_pci) &&
                    !mp_irqs[i].irqtype &&
                    (bus == lbus) &&
                    (slot == ((mp_irqs[i].srcbusirq >> 2) & 0x1f))) {
                        int irq = pin_2_irq(i, ioapic_idx, mp_irqs[i].dstirq);

                        if (!(ioapic_idx || IO_APIC_IRQ(irq)))
                                continue;

                        if (pin == (mp_irqs[i].srcbusirq & 3)) {
                                set_io_apic_irq_attr(irq_attr, ioapic_idx,
                                                     mp_irqs[i].dstirq,
                                                     irq_trigger(i),
                                                     irq_polarity(i));
                                return irq;
                        }
                        /*
                         * Use the first all-but-pin matching entry as a
                         * best-guess fuzzy result for broken mptables.
                         */
                        if (best_guess < 0) {
                                set_io_apic_irq_attr(irq_attr, ioapic_idx,
                                                     mp_irqs[i].dstirq,
                                                     irq_trigger(i),
                                                     irq_polarity(i));
                                best_guess = irq;
                        }
                }
        }
        return best_guess;
}
EXPORT_SYMBOL(IO_APIC_get_PCI_irq_vector);

void lock_vector_lock(void)
{
        /* Used to the online set of cpus does not change
         * during assign_irq_vector.
         */
        raw_spin_lock(&vector_lock);
}

void unlock_vector_lock(void)
{
        raw_spin_unlock(&vector_lock);
}

static int
__assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
{
        /*
         * NOTE! The local APIC isn't very good at handling
         * multiple interrupts at the same interrupt level.
         * As the interrupt level is determined by taking the
         * vector number and shifting that right by 4, we
         * want to spread these out a bit so that they don't
         * all fall in the same interrupt level.
         *
         * Also, we've got to be careful not to trash gate
         * 0x80, because int 0x80 is hm, kind of importantish. ;)
         */
        static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START;
        static int current_offset = VECTOR_OFFSET_START % 16;
        int cpu, err;
        cpumask_var_t tmp_mask;

        if (cfg->move_in_progress)
                return -EBUSY;

        if (!alloc_cpumask_var(&tmp_mask, GFP_ATOMIC))
                return -ENOMEM;

        /* Only try and allocate irqs on cpus that are present */
        err = -ENOSPC;
        cpumask_clear(cfg->old_domain);
        cpu = cpumask_first_and(mask, cpu_online_mask);
        while (cpu < nr_cpu_ids) {
                int new_cpu, vector, offset;

                apic->vector_allocation_domain(cpu, tmp_mask, mask);

                if (cpumask_subset(tmp_mask, cfg->domain)) {
                        err = 0;
                        if (cpumask_equal(tmp_mask, cfg->domain))
                                break;
                        /*
                         * New cpumask using the vector is a proper subset of
                         * the current in use mask. So cleanup the vector
                         * allocation for the members that are not used anymore.
                         */
                        cpumask_andnot(cfg->old_domain, cfg->domain, tmp_mask);
                        cfg->move_in_progress =
                           cpumask_intersects(cfg->old_domain, cpu_online_mask);
                        cpumask_and(cfg->domain, cfg->domain, tmp_mask);
                        break;
                }

                vector = current_vector;
                offset = current_offset;
next:
                vector += 16;
                if (vector >= first_system_vector) {
                        offset = (offset + 1) % 16;
                        vector = FIRST_EXTERNAL_VECTOR + offset;
                }

                if (unlikely(current_vector == vector)) {
                        cpumask_or(cfg->old_domain, cfg->old_domain, tmp_mask);
                        cpumask_andnot(tmp_mask, mask, cfg->old_domain);
                        cpu = cpumask_first_and(tmp_mask, cpu_online_mask);
                        continue;
                }

                if (test_bit(vector, used_vectors))
                        goto next;

                for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask)
                        if (per_cpu(vector_irq, new_cpu)[vector] != -1)
                                goto next;
                /* Found one! */
                current_vector = vector;
                current_offset = offset;
                if (cfg->vector) {
                        cpumask_copy(cfg->old_domain, cfg->domain);
                        cfg->move_in_progress =
                           cpumask_intersects(cfg->old_domain, cpu_online_mask);
                }
                for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask)
                        per_cpu(vector_irq, new_cpu)[vector] = irq;
                cfg->vector = vector;
                cpumask_copy(cfg->domain, tmp_mask);
                err = 0;
                break;
        }
        free_cpumask_var(tmp_mask);
        return err;
}

int assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
{
        int err;
        unsigned long flags;

        raw_spin_lock_irqsave(&vector_lock, flags);
        err = __assign_irq_vector(irq, cfg, mask);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        return err;
}

static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
{
        int cpu, vector;

        BUG_ON(!cfg->vector);

        vector = cfg->vector;
        for_each_cpu_and(cpu, cfg->domain, cpu_online_mask)
                per_cpu(vector_irq, cpu)[vector] = -1;

        cfg->vector = 0;
        cpumask_clear(cfg->domain);

        if (likely(!cfg->move_in_progress))
                return;
        for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) {
                for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
                                                                vector++) {
                        if (per_cpu(vector_irq, cpu)[vector] != irq)
                                continue;
                        per_cpu(vector_irq, cpu)[vector] = -1;
                        break;
                }
        }
        cfg->move_in_progress = 0;
}

void __setup_vector_irq(int cpu)
{
        /* Initialize vector_irq on a new cpu */
        int irq, vector;
        struct irq_cfg *cfg;

        /*
         * vector_lock will make sure that we don't run into irq vector
         * assignments that might be happening on another cpu in parallel,
         * while we setup our initial vector to irq mappings.
         */
        raw_spin_lock(&vector_lock);
        /* Mark the inuse vectors */
        for_each_active_irq(irq) {
                cfg = irq_get_chip_data(irq);
                if (!cfg)
                        continue;

                if (!cpumask_test_cpu(cpu, cfg->domain))
                        continue;
                vector = cfg->vector;
                per_cpu(vector_irq, cpu)[vector] = irq;
        }
        /* Mark the free vectors */
        for (vector = 0; vector < NR_VECTORS; ++vector) {
                irq = per_cpu(vector_irq, cpu)[vector];
                if (irq < 0)
                        continue;

                cfg = irq_cfg(irq);
                if (!cpumask_test_cpu(cpu, cfg->domain))
                        per_cpu(vector_irq, cpu)[vector] = -1;
        }
        raw_spin_unlock(&vector_lock);
}

static struct irq_chip ioapic_chip;

#ifdef CONFIG_X86_32
static inline int IO_APIC_irq_trigger(int irq)
{
        int apic, idx, pin;

        for (apic = 0; apic < nr_ioapics; apic++) {
                for (pin = 0; pin < ioapics[apic].nr_registers; pin++) {
                        idx = find_irq_entry(apic, pin, mp_INT);
                        if ((idx != -1) && (irq == pin_2_irq(idx, apic, pin)))
                                return irq_trigger(idx);
                }
        }
        /*
         * nonexistent IRQs are edge default
         */
        return 0;
}
#else
static inline int IO_APIC_irq_trigger(int irq)
{
        return 1;
}
#endif

static void ioapic_register_intr(unsigned int irq, struct irq_cfg *cfg,
                                 unsigned long trigger)
{
        struct irq_chip *chip = &ioapic_chip;
        irq_flow_handler_t hdl;
        bool fasteoi;

        if ((trigger == IOAPIC_AUTO && IO_APIC_irq_trigger(irq)) ||
            trigger == IOAPIC_LEVEL) {
                irq_set_status_flags(irq, IRQ_LEVEL);
                fasteoi = true;
        } else {
                irq_clear_status_flags(irq, IRQ_LEVEL);
                fasteoi = false;
        }

        if (setup_remapped_irq(irq, cfg, chip))
                fasteoi = trigger != 0;

        hdl = fasteoi ? handle_fasteoi_irq : handle_edge_irq;
        irq_set_chip_and_handler_name(irq, chip, hdl,
                                      fasteoi ? "fasteoi" : "edge");
}

int native_setup_ioapic_entry(int irq, struct IO_APIC_route_entry *entry,
                              unsigned int destination, int vector,
                              struct io_apic_irq_attr *attr)
{
        memset(entry, 0, sizeof(*entry));

        entry->delivery_mode = apic->irq_delivery_mode;
        entry->dest_mode     = apic->irq_dest_mode;
        entry->dest          = destination;
        entry->vector        = vector;
        entry->mask          = 0;                       /* enable IRQ */
        entry->trigger       = attr->trigger;
        entry->polarity      = attr->polarity;

        /*
         * Mask level triggered irqs.
         * Use IRQ_DELAYED_DISABLE for edge triggered irqs.
         */
        if (attr->trigger)
                entry->mask = 1;

        return 0;
}

static void setup_ioapic_irq(unsigned int irq, struct irq_cfg *cfg,
                                struct io_apic_irq_attr *attr)
{
        struct IO_APIC_route_entry entry;
        unsigned int dest;

        if (!IO_APIC_IRQ(irq))
                return;

        if (assign_irq_vector(irq, cfg, apic->target_cpus()))
                return;

        if (apic->cpu_mask_to_apicid_and(cfg->domain, apic->target_cpus(),
                                         &dest)) {
                pr_warn("Failed to obtain apicid for ioapic %d, pin %d\n",
                        mpc_ioapic_id(attr->ioapic), attr->ioapic_pin);
                __clear_irq_vector(irq, cfg);

                return;
        }

        apic_printk(APIC_VERBOSE,KERN_DEBUG
                    "IOAPIC[%d]: Set routing entry (%d-%d -> 0x%x -> "
                    "IRQ %d Mode:%i Active:%i Dest:%d)\n",
                    attr->ioapic, mpc_ioapic_id(attr->ioapic), attr->ioapic_pin,
                    cfg->vector, irq, attr->trigger, attr->polarity, dest);

        if (x86_io_apic_ops.setup_entry(irq, &entry, dest, cfg->vector, attr)) {
                pr_warn("Failed to setup ioapic entry for ioapic  %d, pin %d\n",
                        mpc_ioapic_id(attr->ioapic), attr->ioapic_pin);
                __clear_irq_vector(irq, cfg);

                return;
        }

        ioapic_register_intr(irq, cfg, attr->trigger);
        if (irq < legacy_pic->nr_legacy_irqs)
                legacy_pic->mask(irq);

        ioapic_write_entry(attr->ioapic, attr->ioapic_pin, entry);
}

static bool __init io_apic_pin_not_connected(int idx, int ioapic_idx, int pin)
{
        if (idx != -1)
                return false;

        apic_printk(APIC_VERBOSE, KERN_DEBUG " apic %d pin %d not connected\n",
                    mpc_ioapic_id(ioapic_idx), pin);
        return true;
}

static void __init __io_apic_setup_irqs(unsigned int ioapic_idx)
{
        int idx, node = cpu_to_node(0);
        struct io_apic_irq_attr attr;
        unsigned int pin, irq;

        for (pin = 0; pin < ioapics[ioapic_idx].nr_registers; pin++) {
                idx = find_irq_entry(ioapic_idx, pin, mp_INT);
                if (io_apic_pin_not_connected(idx, ioapic_idx, pin))
                        continue;

                irq = pin_2_irq(idx, ioapic_idx, pin);

                if ((ioapic_idx > 0) && (irq > 16))
                        continue;

                /*
                 * Skip the timer IRQ if there's a quirk handler
                 * installed and if it returns 1:
                 */
                if (apic->multi_timer_check &&
                    apic->multi_timer_check(ioapic_idx, irq))
                        continue;

                set_io_apic_irq_attr(&attr, ioapic_idx, pin, irq_trigger(idx),
                                     irq_polarity(idx));

                io_apic_setup_irq_pin(irq, node, &attr);
        }
}

static void __init setup_IO_APIC_irqs(void)
{
        unsigned int ioapic_idx;

        apic_printk(APIC_VERBOSE, KERN_DEBUG "init IO_APIC IRQs\n");

        for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++)
                __io_apic_setup_irqs(ioapic_idx);
}

/*
 * for the gsit that is not in first ioapic
 * but could not use acpi_register_gsi()
 * like some special sci in IBM x3330
 */
void setup_IO_APIC_irq_extra(u32 gsi)
{
        int ioapic_idx = 0, pin, idx, irq, node = cpu_to_node(0);
        struct io_apic_irq_attr attr;

        /*
         * Convert 'gsi' to 'ioapic.pin'.
         */
        ioapic_idx = mp_find_ioapic(gsi);
        if (ioapic_idx < 0)
                return;

        pin = mp_find_ioapic_pin(ioapic_idx, gsi);
        idx = find_irq_entry(ioapic_idx, pin, mp_INT);
        if (idx == -1)
                return;

        irq = pin_2_irq(idx, ioapic_idx, pin);

        /* Only handle the non legacy irqs on secondary ioapics */
        if (ioapic_idx == 0 || irq < NR_IRQS_LEGACY)
                return;

        set_io_apic_irq_attr(&attr, ioapic_idx, pin, irq_trigger(idx),
                             irq_polarity(idx));

        io_apic_setup_irq_pin_once(irq, node, &attr);
}

/*
 * Set up the timer pin, possibly with the 8259A-master behind.
 */
static void __init setup_timer_IRQ0_pin(unsigned int ioapic_idx,
                                        unsigned int pin, int vector)
{
        struct IO_APIC_route_entry entry;
        unsigned int dest;

        memset(&entry, 0, sizeof(entry));

        /*
         * We use logical delivery to get the timer IRQ
         * to the first CPU.
         */
        if (unlikely(apic->cpu_mask_to_apicid_and(apic->target_cpus(),
                                                  apic->target_cpus(), &dest)))
                dest = BAD_APICID;

        entry.dest_mode = apic->irq_dest_mode;
        entry.mask = 0;                 /* don't mask IRQ for edge */
        entry.dest = dest;
        entry.delivery_mode = apic->irq_delivery_mode;
        entry.polarity = 0;
        entry.trigger = 0;
        entry.vector = vector;

        /*
         * The timer IRQ doesn't have to know that behind the
         * scene we may have a 8259A-master in AEOI mode ...
         */
        irq_set_chip_and_handler_name(0, &ioapic_chip, handle_edge_irq,
                                      "edge");

        /*
         * Add it to the IO-APIC irq-routing table:
         */
        ioapic_write_entry(ioapic_idx, pin, entry);
}

void native_io_apic_print_entries(unsigned int apic, unsigned int nr_entries)
{
        int i;

        pr_debug(" NR Dst Mask Trig IRR Pol Stat Dmod Deli Vect:\n");

        for (i = 0; i <= nr_entries; i++) {
                struct IO_APIC_route_entry entry;

                entry = ioapic_read_entry(apic, i);

                pr_debug(" %02x %02X  ", i, entry.dest);
                pr_cont("%1d    %1d    %1d   %1d   %1d    "
                        "%1d    %1d    %02X\n",
                        entry.mask,
                        entry.trigger,
                        entry.irr,
                        entry.polarity,
                        entry.delivery_status,
                        entry.dest_mode,
                        entry.delivery_mode,
                        entry.vector);
        }
}

void intel_ir_io_apic_print_entries(unsigned int apic,
                                    unsigned int nr_entries)
{
        int i;

        pr_debug(" NR Indx Fmt Mask Trig IRR Pol Stat Indx2 Zero Vect:\n");

        for (i = 0; i <= nr_entries; i++) {
                struct IR_IO_APIC_route_entry *ir_entry;
                struct IO_APIC_route_entry entry;

                entry = ioapic_read_entry(apic, i);

                ir_entry = (struct IR_IO_APIC_route_entry *)&entry;

                pr_debug(" %02x %04X ", i, ir_entry->index);
                pr_cont("%1d   %1d    %1d    %1d   %1d   "
                        "%1d    %1d     %X    %02X\n",
                        ir_entry->format,
                        ir_entry->mask,
                        ir_entry->trigger,
                        ir_entry->irr,
                        ir_entry->polarity,
                        ir_entry->delivery_status,
                        ir_entry->index2,
                        ir_entry->zero,
                        ir_entry->vector);
        }
}

void ioapic_zap_locks(void)
{
        raw_spin_lock_init(&ioapic_lock);
}

__apicdebuginit(void) print_IO_APIC(int ioapic_idx)
{
        union IO_APIC_reg_00 reg_00;
        union IO_APIC_reg_01 reg_01;
        union IO_APIC_reg_02 reg_02;
        union IO_APIC_reg_03 reg_03;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        reg_00.raw = io_apic_read(ioapic_idx, 0);
        reg_01.raw = io_apic_read(ioapic_idx, 1);
        if (reg_01.bits.version >= 0x10)
                reg_02.raw = io_apic_read(ioapic_idx, 2);
        if (reg_01.bits.version >= 0x20)
                reg_03.raw = io_apic_read(ioapic_idx, 3);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        printk(KERN_DEBUG "IO APIC #%d......\n", mpc_ioapic_id(ioapic_idx));
        printk(KERN_DEBUG ".... register #00: %08X\n", reg_00.raw);
        printk(KERN_DEBUG ".......    : physical APIC id: %02X\n", reg_00.bits.ID);
        printk(KERN_DEBUG ".......    : Delivery Type: %X\n", reg_00.bits.delivery_type);
        printk(KERN_DEBUG ".......    : LTS          : %X\n", reg_00.bits.LTS);

        printk(KERN_DEBUG ".... register #01: %08X\n", *(int *)&reg_01);
        printk(KERN_DEBUG ".......     : max redirection entries: %02X\n",
                reg_01.bits.entries);

        printk(KERN_DEBUG ".......     : PRQ implemented: %X\n", reg_01.bits.PRQ);
        printk(KERN_DEBUG ".......     : IO APIC version: %02X\n",
                reg_01.bits.version);

        /*
         * Some Intel chipsets with IO APIC VERSION of 0x1? don't have reg_02,
         * but the value of reg_02 is read as the previous read register
         * value, so ignore it if reg_02 == reg_01.
         */
        if (reg_01.bits.version >= 0x10 && reg_02.raw != reg_01.raw) {
                printk(KERN_DEBUG ".... register #02: %08X\n", reg_02.raw);
                printk(KERN_DEBUG ".......     : arbitration: %02X\n", reg_02.bits.arbitration);
        }

        /*
         * Some Intel chipsets with IO APIC VERSION of 0x2? don't have reg_02
         * or reg_03, but the value of reg_0[23] is read as the previous read
         * register value, so ignore it if reg_03 == reg_0[12].
         */
        if (reg_01.bits.version >= 0x20 && reg_03.raw != reg_02.raw &&
            reg_03.raw != reg_01.raw) {
                printk(KERN_DEBUG ".... register #03: %08X\n", reg_03.raw);
                printk(KERN_DEBUG ".......     : Boot DT    : %X\n", reg_03.bits.boot_DT);
        }

        printk(KERN_DEBUG ".... IRQ redirection table:\n");

        x86_io_apic_ops.print_entries(ioapic_idx, reg_01.bits.entries);
}

__apicdebuginit(void) print_IO_APICs(void)
{
        int ioapic_idx;
        struct irq_cfg *cfg;
        unsigned int irq;
        struct irq_chip *chip;

        printk(KERN_DEBUG "number of MP IRQ sources: %d.\n", mp_irq_entries);
        for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++)
                printk(KERN_DEBUG "number of IO-APIC #%d registers: %d.\n",
                       mpc_ioapic_id(ioapic_idx),
                       ioapics[ioapic_idx].nr_registers);

        /*
         * We are a bit conservative about what we expect.  We have to
         * know about every hardware change ASAP.
         */
        printk(KERN_INFO "testing the IO APIC.......................\n");

        for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++)
                print_IO_APIC(ioapic_idx);

        printk(KERN_DEBUG "IRQ to pin mappings:\n");
        for_each_active_irq(irq) {
                struct irq_pin_list *entry;

                chip = irq_get_chip(irq);
                if (chip != &ioapic_chip)
                        continue;

                cfg = irq_get_chip_data(irq);
                if (!cfg)
                        continue;
                entry = cfg->irq_2_pin;
                if (!entry)
                        continue;
                printk(KERN_DEBUG "IRQ%d ", irq);
                for_each_irq_pin(entry, cfg->irq_2_pin)
                        pr_cont("-> %d:%d", entry->apic, entry->pin);
                pr_cont("\n");
        }

        printk(KERN_INFO ".................................... done.\n");
}

__apicdebuginit(void) print_APIC_field(int base)
{
        int i;

        printk(KERN_DEBUG);

        for (i = 0; i < 8; i++)
                pr_cont("%08x", apic_read(base + i*0x10));

        pr_cont("\n");
}

__apicdebuginit(void) print_local_APIC(void *dummy)
{
        unsigned int i, v, ver, maxlvt;
        u64 icr;

        printk(KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
                smp_processor_id(), hard_smp_processor_id());
        v = apic_read(APIC_ID);
        printk(KERN_INFO "... APIC ID:      %08x (%01x)\n", v, read_apic_id());
        v = apic_read(APIC_LVR);
        printk(KERN_INFO "... APIC VERSION: %08x\n", v);
        ver = GET_APIC_VERSION(v);
        maxlvt = lapic_get_maxlvt();

        v = apic_read(APIC_TASKPRI);
        printk(KERN_DEBUG "... APIC TASKPRI: %08x (%02x)\n", v, v & APIC_TPRI_MASK);

        if (APIC_INTEGRATED(ver)) {                     /* !82489DX */
                if (!APIC_XAPIC(ver)) {
                        v = apic_read(APIC_ARBPRI);
                        printk(KERN_DEBUG "... APIC ARBPRI: %08x (%02x)\n", v,
                               v & APIC_ARBPRI_MASK);
                }
                v = apic_read(APIC_PROCPRI);
                printk(KERN_DEBUG "... APIC PROCPRI: %08x\n", v);
        }

        /*
         * Remote read supported only in the 82489DX and local APIC for
         * Pentium processors.
         */
        if (!APIC_INTEGRATED(ver) || maxlvt == 3) {
                v = apic_read(APIC_RRR);
                printk(KERN_DEBUG "... APIC RRR: %08x\n", v);
        }

        v = apic_read(APIC_LDR);
        printk(KERN_DEBUG "... APIC LDR: %08x\n", v);
        if (!x2apic_enabled()) {
                v = apic_read(APIC_DFR);
                printk(KERN_DEBUG "... APIC DFR: %08x\n", v);
        }
        v = apic_read(APIC_SPIV);
        printk(KERN_DEBUG "... APIC SPIV: %08x\n", v);

        printk(KERN_DEBUG "... APIC ISR field:\n");
        print_APIC_field(APIC_ISR);
        printk(KERN_DEBUG "... APIC TMR field:\n");
        print_APIC_field(APIC_TMR);
        printk(KERN_DEBUG "... APIC IRR field:\n");
        print_APIC_field(APIC_IRR);

        if (APIC_INTEGRATED(ver)) {             /* !82489DX */
                if (maxlvt > 3)         /* Due to the Pentium erratum 3AP. */
                        apic_write(APIC_ESR, 0);

                v = apic_read(APIC_ESR);
                printk(KERN_DEBUG "... APIC ESR: %08x\n", v);
        }

        icr = apic_icr_read();
        printk(KERN_DEBUG "... APIC ICR: %08x\n", (u32)icr);
        printk(KERN_DEBUG "... APIC ICR2: %08x\n", (u32)(icr >> 32));

        v = apic_read(APIC_LVTT);
        printk(KERN_DEBUG "... APIC LVTT: %08x\n", v);

        if (maxlvt > 3) {                       /* PC is LVT#4. */
                v = apic_read(APIC_LVTPC);
                printk(KERN_DEBUG "... APIC LVTPC: %08x\n", v);
        }
        v = apic_read(APIC_LVT0);
        printk(KERN_DEBUG "... APIC LVT0: %08x\n", v);
        v = apic_read(APIC_LVT1);
        printk(KERN_DEBUG "... APIC LVT1: %08x\n", v);

        if (maxlvt > 2) {                       /* ERR is LVT#3. */
                v = apic_read(APIC_LVTERR);
                printk(KERN_DEBUG "... APIC LVTERR: %08x\n", v);
        }

        v = apic_read(APIC_TMICT);
        printk(KERN_DEBUG "... APIC TMICT: %08x\n", v);
        v = apic_read(APIC_TMCCT);
        printk(KERN_DEBUG "... APIC TMCCT: %08x\n", v);
        v = apic_read(APIC_TDCR);
        printk(KERN_DEBUG "... APIC TDCR: %08x\n", v);

        if (boot_cpu_has(X86_FEATURE_EXTAPIC)) {
                v = apic_read(APIC_EFEAT);
                maxlvt = (v >> 16) & 0xff;
                printk(KERN_DEBUG "... APIC EFEAT: %08x\n", v);
                v = apic_read(APIC_ECTRL);
                printk(KERN_DEBUG "... APIC ECTRL: %08x\n", v);
                for (i = 0; i < maxlvt; i++) {
                        v = apic_read(APIC_EILVTn(i));
                        printk(KERN_DEBUG "... APIC EILVT%d: %08x\n", i, v);
                }
        }
        pr_cont("\n");
}

__apicdebuginit(void) print_local_APICs(int maxcpu)
{
        int cpu;

        if (!maxcpu)
                return;

        preempt_disable();
        for_each_online_cpu(cpu) {
                if (cpu >= maxcpu)
                        break;
                smp_call_function_single(cpu, print_local_APIC, NULL, 1);
        }
        preempt_enable();
}

__apicdebuginit(void) print_PIC(void)
{
        unsigned int v;
        unsigned long flags;

        if (!legacy_pic->nr_legacy_irqs)
                return;

        printk(KERN_DEBUG "\nprinting PIC contents\n");

        raw_spin_lock_irqsave(&i8259A_lock, flags);

        v = inb(0xa1) << 8 | inb(0x21);
        printk(KERN_DEBUG "... PIC  IMR: %04x\n", v);

        v = inb(0xa0) << 8 | inb(0x20);
        printk(KERN_DEBUG "... PIC  IRR: %04x\n", v);

        outb(0x0b,0xa0);
        outb(0x0b,0x20);
        v = inb(0xa0) << 8 | inb(0x20);
        outb(0x0a,0xa0);
        outb(0x0a,0x20);

        raw_spin_unlock_irqrestore(&i8259A_lock, flags);

        printk(KERN_DEBUG "... PIC  ISR: %04x\n", v);

        v = inb(0x4d1) << 8 | inb(0x4d0);
        printk(KERN_DEBUG "... PIC ELCR: %04x\n", v);
}

static int __initdata show_lapic = 1;
static __init int setup_show_lapic(char *arg)
{
        int num = -1;

        if (strcmp(arg, "all") == 0) {
                show_lapic = CONFIG_NR_CPUS;
        } else {
                get_option(&arg, &num);
                if (num >= 0)
                        show_lapic = num;
        }

        return 1;
}
__setup("show_lapic=", setup_show_lapic);

__apicdebuginit(int) print_ICs(void)
{
        if (apic_verbosity == APIC_QUIET)
                return 0;

        print_PIC();

        /* don't print out if apic is not there */
        if (!cpu_has_apic && !apic_from_smp_config())
                return 0;

        print_local_APICs(show_lapic);
        print_IO_APICs();

        return 0;
}

late_initcall(print_ICs);


/* Where if anywhere is the i8259 connect in external int mode */
static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };

void __init enable_IO_APIC(void)
{
        int i8259_apic, i8259_pin;
        int apic;

        if (!legacy_pic->nr_legacy_irqs)
                return;

        for(apic = 0; apic < nr_ioapics; apic++) {
                int pin;
                /* See if any of the pins is in ExtINT mode */
                for (pin = 0; pin < ioapics[apic].nr_registers; pin++) {
                        struct IO_APIC_route_entry entry;
                        entry = ioapic_read_entry(apic, pin);

                        /* If the interrupt line is enabled and in ExtInt mode
                         * I have found the pin where the i8259 is connected.
                         */
                        if ((entry.mask == 0) && (entry.delivery_mode == dest_ExtINT)) {
                                ioapic_i8259.apic = apic;
                                ioapic_i8259.pin  = pin;
                                goto found_i8259;
                        }
                }
        }
 found_i8259:
        /* Look to see what if the MP table has reported the ExtINT */
        /* If we could not find the appropriate pin by looking at the ioapic
         * the i8259 probably is not connected the ioapic but give the
         * mptable a chance anyway.
         */
        i8259_pin  = find_isa_irq_pin(0, mp_ExtINT);
        i8259_apic = find_isa_irq_apic(0, mp_ExtINT);
        /* Trust the MP table if nothing is setup in the hardware */
        if ((ioapic_i8259.pin == -1) && (i8259_pin >= 0)) {
                printk(KERN_WARNING "ExtINT not setup in hardware but reported by MP table\n");
                ioapic_i8259.pin  = i8259_pin;
                ioapic_i8259.apic = i8259_apic;
        }
        /* Complain if the MP table and the hardware disagree */
        if (((ioapic_i8259.apic != i8259_apic) || (ioapic_i8259.pin != i8259_pin)) &&
                (i8259_pin >= 0) && (ioapic_i8259.pin >= 0))
        {
                printk(KERN_WARNING "ExtINT in hardware and MP table differ\n");
        }

        /*
         * Do not trust the IO-APIC being empty at bootup
         */
        clear_IO_APIC();
}

void native_disable_io_apic(void)
{
        /*
         * If the i8259 is routed through an IOAPIC
         * Put that IOAPIC in virtual wire mode
         * so legacy interrupts can be delivered.
         */
        if (ioapic_i8259.pin != -1) {
                struct IO_APIC_route_entry entry;

                memset(&entry, 0, sizeof(entry));
                entry.mask            = 0; /* Enabled */
                entry.trigger         = 0; /* Edge */
                entry.irr             = 0;
                entry.polarity        = 0; /* High */
                entry.delivery_status = 0;
                entry.dest_mode       = 0; /* Physical */
                entry.delivery_mode   = dest_ExtINT; /* ExtInt */
                entry.vector          = 0;
                entry.dest            = read_apic_id();

                /*
                 * Add it to the IO-APIC irq-routing table:
                 */
                ioapic_write_entry(ioapic_i8259.apic, ioapic_i8259.pin, entry);
        }

        if (cpu_has_apic || apic_from_smp_config())
                disconnect_bsp_APIC(ioapic_i8259.pin != -1);

}

/*
 * Not an __init, needed by the reboot code
 */
void disable_IO_APIC(void)
{
        /*
         * Clear the IO-APIC before rebooting:
         */
        clear_IO_APIC();

        if (!legacy_pic->nr_legacy_irqs)
                return;

        x86_io_apic_ops.disable();
}

#ifdef CONFIG_X86_32
/*
 * function to set the IO-APIC physical IDs based on the
 * values stored in the MPC table.
 *
 * by Matt Domsch <Matt_Domsch@dell.com>  Tue Dec 21 12:25:05 CST 1999
 */
void __init setup_ioapic_ids_from_mpc_nocheck(void)
{
        union IO_APIC_reg_00 reg_00;
        physid_mask_t phys_id_present_map;
        int ioapic_idx;
        int i;
        unsigned char old_id;
        unsigned long flags;

        /*
         * This is broken; anything with a real cpu count has to
         * circumvent this idiocy regardless.
         */
        apic->ioapic_phys_id_map(&phys_cpu_present_map, &phys_id_present_map);

        /*
         * Set the IOAPIC ID to the value stored in the MPC table.
         */
        for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++) {
                /* Read the register 0 value */
                raw_spin_lock_irqsave(&ioapic_lock, flags);
                reg_00.raw = io_apic_read(ioapic_idx, 0);
                raw_spin_unlock_irqrestore(&ioapic_lock, flags);

                old_id = mpc_ioapic_id(ioapic_idx);

                if (mpc_ioapic_id(ioapic_idx) >= get_physical_broadcast()) {
                        printk(KERN_ERR "BIOS bug, IO-APIC#%d ID is %d in the MPC table!...\n",
                                ioapic_idx, mpc_ioapic_id(ioapic_idx));
                        printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
                                reg_00.bits.ID);
                        ioapics[ioapic_idx].mp_config.apicid = reg_00.bits.ID;
                }

                /*
                 * Sanity check, is the ID really free? Every APIC in a
                 * system must have a unique ID or we get lots of nice
                 * 'stuck on smp_invalidate_needed IPI wait' messages.
                 */
                if (apic->check_apicid_used(&phys_id_present_map,
                                            mpc_ioapic_id(ioapic_idx))) {
                        printk(KERN_ERR "BIOS bug, IO-APIC#%d ID %d is already used!...\n",
                                ioapic_idx, mpc_ioapic_id(ioapic_idx));
                        for (i = 0; i < get_physical_broadcast(); i++)
                                if (!physid_isset(i, phys_id_present_map))
                                        break;
                        if (i >= get_physical_broadcast())
                                panic("Max APIC ID exceeded!\n");

                        printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
                                i);
                        physid_set(i, phys_id_present_map);
                        ioapics[ioapic_idx].mp_config.apicid = i;
                } else {
                        physid_mask_t tmp;
                        apic->apicid_to_cpu_present(mpc_ioapic_id(ioapic_idx),
                                                    &tmp);
                        apic_printk(APIC_VERBOSE, "Setting %d in the "
                                        "phys_id_present_map\n",
                                        mpc_ioapic_id(ioapic_idx));
                        physids_or(phys_id_present_map, phys_id_present_map, tmp);
                }

                /*
                 * We need to adjust the IRQ routing table
                 * if the ID changed.
                 */
                if (old_id != mpc_ioapic_id(ioapic_idx))
                        for (i = 0; i < mp_irq_entries; i++)
                                if (mp_irqs[i].dstapic == old_id)
                                        mp_irqs[i].dstapic
                                                = mpc_ioapic_id(ioapic_idx);

                /*
                 * Update the ID register according to the right value
                 * from the MPC table if they are different.
                 */
                if (mpc_ioapic_id(ioapic_idx) == reg_00.bits.ID)
                        continue;

                apic_printk(APIC_VERBOSE, KERN_INFO
                        "...changing IO-APIC physical APIC ID to %d ...",
                        mpc_ioapic_id(ioapic_idx));

                reg_00.bits.ID = mpc_ioapic_id(ioapic_idx);
                raw_spin_lock_irqsave(&ioapic_lock, flags);
                io_apic_write(ioapic_idx, 0, reg_00.raw);
                raw_spin_unlock_irqrestore(&ioapic_lock, flags);

                /*
                 * Sanity check
                 */
                raw_spin_lock_irqsave(&ioapic_lock, flags);
                reg_00.raw = io_apic_read(ioapic_idx, 0);
                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
                if (reg_00.bits.ID != mpc_ioapic_id(ioapic_idx))
                        pr_cont("could not set ID!\n");
                else
                        apic_printk(APIC_VERBOSE, " ok.\n");
        }
}

void __init setup_ioapic_ids_from_mpc(void)
{

        if (acpi_ioapic)
                return;
        /*
         * Don't check I/O APIC IDs for xAPIC systems.  They have
         * no meaning without the serial APIC bus.
         */
        if (!(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
                || APIC_XAPIC(apic_version[boot_cpu_physical_apicid]))
                return;
        setup_ioapic_ids_from_mpc_nocheck();
}
#endif

int no_timer_check __initdata;

static int __init notimercheck(char *s)
{
        no_timer_check = 1;
        return 1;
}
__setup("no_timer_check", notimercheck);

/*
 * There is a nasty bug in some older SMP boards, their mptable lies
 * about the timer IRQ. We do the following to work around the situation:
 *
 *      - timer IRQ defaults to IO-APIC IRQ
 *      - if this function detects that timer IRQs are defunct, then we fall
 *        back to ISA timer IRQs
 */
static int __init timer_irq_works(void)
{
        unsigned long t1 = jiffies;
        unsigned long flags;

        if (no_timer_check)
                return 1;

        local_save_flags(flags);
        local_irq_enable();
        /* Let ten ticks pass... */
        mdelay((10 * 1000) / HZ);
        local_irq_restore(flags);

        /*
         * Expect a few ticks at least, to be sure some possible
         * glue logic does not lock up after one or two first
         * ticks in a non-ExtINT mode.  Also the local APIC
         * might have cached one ExtINT interrupt.  Finally, at
         * least one tick may be lost due to delays.
         */

        /* jiffies wrap? */
        if (time_after(jiffies, t1 + 4))
                return 1;
        return 0;
}

/*
 * In the SMP+IOAPIC case it might happen that there are an unspecified
 * number of pending IRQ events unhandled. These cases are very rare,
 * so we 'resend' these IRQs via IPIs, to the same CPU. It's much
 * better to do it this way as thus we do not have to be aware of
 * 'pending' interrupts in the IRQ path, except at this point.
 */
/*
 * Edge triggered needs to resend any interrupt
 * that was delayed but this is now handled in the device
 * independent code.
 */

/*
 * Starting up a edge-triggered IO-APIC interrupt is
 * nasty - we need to make sure that we get the edge.
 * If it is already asserted for some reason, we need
 * return 1 to indicate that is was pending.
 *
 * This is not complete - we should be able to fake
 * an edge even if it isn't on the 8259A...
 */

static unsigned int startup_ioapic_irq(struct irq_data *data)
{
        int was_pending = 0, irq = data->irq;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        if (irq < legacy_pic->nr_legacy_irqs) {
                legacy_pic->mask(irq);
                if (legacy_pic->irq_pending(irq))
                        was_pending = 1;
        }
        __unmask_ioapic(data->chip_data);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        return was_pending;
}

static int ioapic_retrigger_irq(struct irq_data *data)
{
        struct irq_cfg *cfg = data->chip_data;
        unsigned long flags;
        int cpu;

        raw_spin_lock_irqsave(&vector_lock, flags);
        cpu = cpumask_first_and(cfg->domain, cpu_online_mask);
        apic->send_IPI_mask(cpumask_of(cpu), cfg->vector);
        raw_spin_unlock_irqrestore(&vector_lock, flags);

        return 1;
}

/*
 * Level and edge triggered IO-APIC interrupts need different handling,
 * so we use two separate IRQ descriptors. Edge triggered IRQs can be
 * handled with the level-triggered descriptor, but that one has slightly
 * more overhead. Level-triggered interrupts cannot be handled with the
 * edge-triggered handler, without risking IRQ storms and other ugly
 * races.
 */

#ifdef CONFIG_SMP
void send_cleanup_vector(struct irq_cfg *cfg)
{
        cpumask_var_t cleanup_mask;

        if (unlikely(!alloc_cpumask_var(&cleanup_mask, GFP_ATOMIC))) {
                unsigned int i;
                for_each_cpu_and(i, cfg->old_domain, cpu_online_mask)
                        apic->send_IPI_mask(cpumask_of(i), IRQ_MOVE_CLEANUP_VECTOR);
        } else {
                cpumask_and(cleanup_mask, cfg->old_domain, cpu_online_mask);
                apic->send_IPI_mask(cleanup_mask, IRQ_MOVE_CLEANUP_VECTOR);
                free_cpumask_var(cleanup_mask);
        }
        cfg->move_in_progress = 0;
}

asmlinkage void smp_irq_move_cleanup_interrupt(void)
{
        unsigned vector, me;

        ack_APIC_irq();
        irq_enter();
        exit_idle();

        me = smp_processor_id();
        for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
                unsigned int irq;
                unsigned int irr;
                struct irq_desc *desc;
                struct irq_cfg *cfg;
                irq = __this_cpu_read(vector_irq[vector]);

                if (irq == -1)
                        continue;

                desc = irq_to_desc(irq);
                if (!desc)
                        continue;

                cfg = irq_cfg(irq);
                if (!cfg)
                        continue;

                raw_spin_lock(&desc->lock);

                /*
                 * Check if the irq migration is in progress. If so, we
                 * haven't received the cleanup request yet for this irq.
                 */
                if (cfg->move_in_progress)
                        goto unlock;

                if (vector == cfg->vector && cpumask_test_cpu(me, cfg->domain))
                        goto unlock;

                irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
                /*
                 * Check if the vector that needs to be cleanedup is
                 * registered at the cpu's IRR. If so, then this is not
                 * the best time to clean it up. Lets clean it up in the
                 * next attempt by sending another IRQ_MOVE_CLEANUP_VECTOR
                 * to myself.
                 */
                if (irr  & (1 << (vector % 32))) {
                        apic->send_IPI_self(IRQ_MOVE_CLEANUP_VECTOR);
                        goto unlock;
                }
                __this_cpu_write(vector_irq[vector], -1);
unlock:
                raw_spin_unlock(&desc->lock);
        }

        irq_exit();
}

static void __irq_complete_move(struct irq_cfg *cfg, unsigned vector)
{
        unsigned me;

        if (likely(!cfg->move_in_progress))
                return;

        me = smp_processor_id();

        if (vector == cfg->vector && cpumask_test_cpu(me, cfg->domain))
                send_cleanup_vector(cfg);
}

static void irq_complete_move(struct irq_cfg *cfg)
{
        __irq_complete_move(cfg, ~get_irq_regs()->orig_ax);
}

void irq_force_complete_move(int irq)
{
        struct irq_cfg *cfg = irq_get_chip_data(irq);

        if (!cfg)
                return;

        __irq_complete_move(cfg, cfg->vector);
}
#else
static inline void irq_complete_move(struct irq_cfg *cfg) { }
#endif

static void __target_IO_APIC_irq(unsigned int irq, unsigned int dest, struct irq_cfg *cfg)
{
        int apic, pin;
        struct irq_pin_list *entry;
        u8 vector = cfg->vector;

        for_each_irq_pin(entry, cfg->irq_2_pin) {
                unsigned int reg;

                apic = entry->apic;
                pin = entry->pin;

                io_apic_write(apic, 0x11 + pin*2, dest);
                reg = io_apic_read(apic, 0x10 + pin*2);
                reg &= ~IO_APIC_REDIR_VECTOR_MASK;
                reg |= vector;
                io_apic_modify(apic, 0x10 + pin*2, reg);
        }
}

/*
 * Either sets data->affinity to a valid value, and returns
 * ->cpu_mask_to_apicid of that in dest_id, or returns -1 and
 * leaves data->affinity untouched.
 */
int __ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask,
                          unsigned int *dest_id)
{
        struct irq_cfg *cfg = data->chip_data;
        unsigned int irq = data->irq;
        int err;

        if (!config_enabled(CONFIG_SMP))
                return -1;

        if (!cpumask_intersects(mask, cpu_online_mask))
                return -EINVAL;

        err = assign_irq_vector(irq, cfg, mask);
        if (err)
                return err;

        err = apic->cpu_mask_to_apicid_and(mask, cfg->domain, dest_id);
        if (err) {
                if (assign_irq_vector(irq, cfg, data->affinity))
                        pr_err("Failed to recover vector for irq %d\n", irq);
                return err;
        }

        cpumask_copy(data->affinity, mask);

        return 0;
}


int native_ioapic_set_affinity(struct irq_data *data,
                               const struct cpumask *mask,
                               bool force)
{
        unsigned int dest, irq = data->irq;
        unsigned long flags;
        int ret;

        if (!config_enabled(CONFIG_SMP))
                return -1;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        ret = __ioapic_set_affinity(data, mask, &dest);
        if (!ret) {
                /* Only the high 8 bits are valid. */
                dest = SET_APIC_LOGICAL_ID(dest);
                __target_IO_APIC_irq(irq, dest, data->chip_data);
                ret = IRQ_SET_MASK_OK_NOCOPY;
        }
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
        return ret;
}

static void ack_apic_edge(struct irq_data *data)
{
        irq_complete_move(data->chip_data);
        irq_move_irq(data);
        ack_APIC_irq();
}

atomic_t irq_mis_count;

#ifdef CONFIG_GENERIC_PENDING_IRQ
static bool io_apic_level_ack_pending(struct irq_cfg *cfg)
{
        struct irq_pin_list *entry;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        for_each_irq_pin(entry, cfg->irq_2_pin) {
                unsigned int reg;
                int pin;

                pin = entry->pin;
                reg = io_apic_read(entry->apic, 0x10 + pin*2);
                /* Is the remote IRR bit set? */
                if (reg & IO_APIC_REDIR_REMOTE_IRR) {
                        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
                        return true;
                }
        }
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        return false;
}

static inline bool ioapic_irqd_mask(struct irq_data *data, struct irq_cfg *cfg)
{
        /* If we are moving the irq we need to mask it */
        if (unlikely(irqd_is_setaffinity_pending(data))) {
                mask_ioapic(cfg);
                return true;
        }
        return false;
}

static inline void ioapic_irqd_unmask(struct irq_data *data,
                                      struct irq_cfg *cfg, bool masked)
{
        if (unlikely(masked)) {
                /* Only migrate the irq if the ack has been received.
                 *
                 * On rare occasions the broadcast level triggered ack gets
                 * delayed going to ioapics, and if we reprogram the
                 * vector while Remote IRR is still set the irq will never
                 * fire again.
                 *
                 * To prevent this scenario we read the Remote IRR bit
                 * of the ioapic.  This has two effects.
                 * - On any sane system the read of the ioapic will
                 *   flush writes (and acks) going to the ioapic from
                 *   this cpu.
                 * - We get to see if the ACK has actually been delivered.
                 *
                 * Based on failed experiments of reprogramming the
                 * ioapic entry from outside of irq context starting
                 * with masking the ioapic entry and then polling until
                 * Remote IRR was clear before reprogramming the
                 * ioapic I don't trust the Remote IRR bit to be
                 * completey accurate.
                 *
                 * However there appears to be no other way to plug
                 * this race, so if the Remote IRR bit is not
                 * accurate and is causing problems then it is a hardware bug
                 * and you can go talk to the chipset vendor about it.
                 */
                if (!io_apic_level_ack_pending(cfg))
                        irq_move_masked_irq(data);
                unmask_ioapic(cfg);
        }
}
#else
static inline bool ioapic_irqd_mask(struct irq_data *data, struct irq_cfg *cfg)
{
        return false;
}
static inline void ioapic_irqd_unmask(struct irq_data *data,
                                      struct irq_cfg *cfg, bool masked)
{
}
#endif

static void ack_apic_level(struct irq_data *data)
{
        struct irq_cfg *cfg = data->chip_data;
        int i, irq = data->irq;
        unsigned long v;
        bool masked;

        irq_complete_move(cfg);
        masked = ioapic_irqd_mask(data, cfg);

        /*
         * It appears there is an erratum which affects at least version 0x11
         * of I/O APIC (that's the 82093AA and cores integrated into various
         * chipsets).  Under certain conditions a level-triggered interrupt is
         * erroneously delivered as edge-triggered one but the respective IRR
         * bit gets set nevertheless.  As a result the I/O unit expects an EOI
         * message but it will never arrive and further interrupts are blocked
         * from the source.  The exact reason is so far unknown, but the
         * phenomenon was observed when two consecutive interrupt requests
         * from a given source get delivered to the same CPU and the source is
         * temporarily disabled in between.
         *
         * A workaround is to simulate an EOI message manually.  We achieve it
         * by setting the trigger mode to edge and then to level when the edge
         * trigger mode gets detected in the TMR of a local APIC for a
         * level-triggered interrupt.  We mask the source for the time of the
         * operation to prevent an edge-triggered interrupt escaping meanwhile.
         * The idea is from Manfred Spraul.  --macro
         *
         * Also in the case when cpu goes offline, fixup_irqs() will forward
         * any unhandled interrupt on the offlined cpu to the new cpu
         * destination that is handling the corresponding interrupt. This
         * interrupt forwarding is done via IPI's. Hence, in this case also
         * level-triggered io-apic interrupt will be seen as an edge
         * interrupt in the IRR. And we can't rely on the cpu's EOI
         * to be broadcasted to the IO-APIC's which will clear the remoteIRR
         * corresponding to the level-triggered interrupt. Hence on IO-APIC's
         * supporting EOI register, we do an explicit EOI to clear the
         * remote IRR and on IO-APIC's which don't have an EOI register,
         * we use the above logic (mask+edge followed by unmask+level) from
         * Manfred Spraul to clear the remote IRR.
         */
        i = cfg->vector;
        v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));

        /*
         * We must acknowledge the irq before we move it or the acknowledge will
         * not propagate properly.
         */
        ack_APIC_irq();

        /*
         * Tail end of clearing remote IRR bit (either by delivering the EOI
         * message via io-apic EOI register write or simulating it using
         * mask+edge followed by unnask+level logic) manually when the
         * level triggered interrupt is seen as the edge triggered interrupt
         * at the cpu.
         */
        if (!(v & (1 << (i & 0x1f)))) {
                atomic_inc(&irq_mis_count);

                eoi_ioapic_irq(irq, cfg);
        }

        ioapic_irqd_unmask(data, cfg, masked);
}

static struct irq_chip ioapic_chip __read_mostly = {
        .name                   = "IO-APIC",
        .irq_startup            = startup_ioapic_irq,
        .irq_mask               = mask_ioapic_irq,
        .irq_unmask             = unmask_ioapic_irq,
        .irq_ack                = ack_apic_edge,
        .irq_eoi                = ack_apic_level,
        .irq_set_affinity       = native_ioapic_set_affinity,
        .irq_retrigger          = ioapic_retrigger_irq,
};

static inline void init_IO_APIC_traps(void)
{
        struct irq_cfg *cfg;
        unsigned int irq;

        /*
         * NOTE! The local APIC isn't very good at handling
         * multiple interrupts at the same interrupt level.
         * As the interrupt level is determined by taking the
         * vector number and shifting that right by 4, we
         * want to spread these out a bit so that they don't
         * all fall in the same interrupt level.
         *
         * Also, we've got to be careful not to trash gate
         * 0x80, because int 0x80 is hm, kind of importantish. ;)
         */
        for_each_active_irq(irq) {
                cfg = irq_get_chip_data(irq);
                if (IO_APIC_IRQ(irq) && cfg && !cfg->vector) {
                        /*
                         * Hmm.. We don't have an entry for this,
                         * so default to an old-fashioned 8259
                         * interrupt if we can..
                         */
                        if (irq < legacy_pic->nr_legacy_irqs)
                                legacy_pic->make_irq(irq);
                        else
                                /* Strange. Oh, well.. */
                                irq_set_chip(irq, &no_irq_chip);
                }
        }
}

/*
 * The local APIC irq-chip implementation:
 */

static void mask_lapic_irq(struct irq_data *data)
{
        unsigned long v;

        v = apic_read(APIC_LVT0);
        apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
}

static void unmask_lapic_irq(struct irq_data *data)
{
        unsigned long v;

        v = apic_read(APIC_LVT0);
        apic_write(APIC_LVT0, v & ~APIC_LVT_MASKED);
}

static void ack_lapic_irq(struct irq_data *data)
{
        ack_APIC_irq();
}

static struct irq_chip lapic_chip __read_mostly = {
        .name           = "local-APIC",
        .irq_mask       = mask_lapic_irq,
        .irq_unmask     = unmask_lapic_irq,
        .irq_ack        = ack_lapic_irq,
};

static void lapic_register_intr(int irq)
{
        irq_clear_status_flags(irq, IRQ_LEVEL);
        irq_set_chip_and_handler_name(irq, &lapic_chip, handle_edge_irq,
                                      "edge");
}

/*
 * This looks a bit hackish but it's about the only one way of sending
 * a few INTA cycles to 8259As and any associated glue logic.  ICR does
 * not support the ExtINT mode, unfortunately.  We need to send these
 * cycles as some i82489DX-based boards have glue logic that keeps the
 * 8259A interrupt line asserted until INTA.  --macro
 */
static inline void __init unlock_ExtINT_logic(void)
{
        int apic, pin, i;
        struct IO_APIC_route_entry entry0, entry1;
        unsigned char save_control, save_freq_select;

        pin  = find_isa_irq_pin(8, mp_INT);
        if (pin == -1) {
                WARN_ON_ONCE(1);
                return;
        }
        apic = find_isa_irq_apic(8, mp_INT);
        if (apic == -1) {
                WARN_ON_ONCE(1);
                return;
        }

        entry0 = ioapic_read_entry(apic, pin);
        clear_IO_APIC_pin(apic, pin);

        memset(&entry1, 0, sizeof(entry1));

        entry1.dest_mode = 0;                   /* physical delivery */
        entry1.mask = 0;                        /* unmask IRQ now */
        entry1.dest = hard_smp_processor_id();
        entry1.delivery_mode = dest_ExtINT;
        entry1.polarity = entry0.polarity;
        entry1.trigger = 0;
        entry1.vector = 0;

        ioapic_write_entry(apic, pin, entry1);

        save_control = CMOS_READ(RTC_CONTROL);
        save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
        CMOS_WRITE((save_freq_select & ~RTC_RATE_SELECT) | 0x6,
                   RTC_FREQ_SELECT);
        CMOS_WRITE(save_control | RTC_PIE, RTC_CONTROL);

        i = 100;
        while (i-- > 0) {
                mdelay(10);
                if ((CMOS_READ(RTC_INTR_FLAGS) & RTC_PF) == RTC_PF)
                        i -= 10;
        }

        CMOS_WRITE(save_control, RTC_CONTROL);
        CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
        clear_IO_APIC_pin(apic, pin);

        ioapic_write_entry(apic, pin, entry0);
}

static int disable_timer_pin_1 __initdata;
/* Actually the next is obsolete, but keep it for paranoid reasons -AK */
static int __init disable_timer_pin_setup(char *arg)
{
        disable_timer_pin_1 = 1;
        return 0;
}
early_param("disable_timer_pin_1", disable_timer_pin_setup);

int timer_through_8259 __initdata;

/*
 * This code may look a bit paranoid, but it's supposed to cooperate with
 * a wide range of boards and BIOS bugs.  Fortunately only the timer IRQ
 * is so screwy.  Thanks to Brian Perkins for testing/hacking this beast
 * fanatically on his truly buggy board.
 *
 * FIXME: really need to revamp this for all platforms.
 */
static inline void __init check_timer(void)
{
        struct irq_cfg *cfg = irq_get_chip_data(0);
        int node = cpu_to_node(0);
        int apic1, pin1, apic2, pin2;
        unsigned long flags;
        int no_pin1 = 0;

        local_irq_save(flags);

        /*
         * get/set the timer IRQ vector:
         */
        legacy_pic->mask(0);
        assign_irq_vector(0, cfg, apic->target_cpus());

        /*
         * As IRQ0 is to be enabled in the 8259A, the virtual
         * wire has to be disabled in the local APIC.  Also
         * timer interrupts need to be acknowledged manually in
         * the 8259A for the i82489DX when using the NMI
         * watchdog as that APIC treats NMIs as level-triggered.
         * The AEOI mode will finish them in the 8259A
         * automatically.
         */
        apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
        legacy_pic->init(1);

        pin1  = find_isa_irq_pin(0, mp_INT);
        apic1 = find_isa_irq_apic(0, mp_INT);
        pin2  = ioapic_i8259.pin;
        apic2 = ioapic_i8259.apic;

        apic_printk(APIC_QUIET, KERN_INFO "..TIMER: vector=0x%02X "
                    "apic1=%d pin1=%d apic2=%d pin2=%d\n",
                    cfg->vector, apic1, pin1, apic2, pin2);

        /*
         * Some BIOS writers are clueless and report the ExtINTA
         * I/O APIC input from the cascaded 8259A as the timer
         * interrupt input.  So just in case, if only one pin
         * was found above, try it both directly and through the
         * 8259A.
         */
        if (pin1 == -1) {
                panic_if_irq_remap("BIOS bug: timer not connected to IO-APIC");
                pin1 = pin2;
                apic1 = apic2;
                no_pin1 = 1;
        } else if (pin2 == -1) {
                pin2 = pin1;
                apic2 = apic1;
        }

        if (pin1 != -1) {
                /*
                 * Ok, does IRQ0 through the IOAPIC work?
                 */
                if (no_pin1) {
                        add_pin_to_irq_node(cfg, node, apic1, pin1);
                        setup_timer_IRQ0_pin(apic1, pin1, cfg->vector);
                } else {
                        /* for edge trigger, setup_ioapic_irq already
                         * leave it unmasked.
                         * so only need to unmask if it is level-trigger
                         * do we really have level trigger timer?
                         */
                        int idx;
                        idx = find_irq_entry(apic1, pin1, mp_INT);
                        if (idx != -1 && irq_trigger(idx))
                                unmask_ioapic(cfg);
                }
                if (timer_irq_works()) {
                        if (disable_timer_pin_1 > 0)
                                clear_IO_APIC_pin(0, pin1);
                        goto out;
                }
                panic_if_irq_remap("timer doesn't work through Interrupt-remapped IO-APIC");
                local_irq_disable();
                clear_IO_APIC_pin(apic1, pin1);
                if (!no_pin1)
                        apic_printk(APIC_QUIET, KERN_ERR "..MP-BIOS bug: "
                                    "8254 timer not connected to IO-APIC\n");

                apic_printk(APIC_QUIET, KERN_INFO "...trying to set up timer "
                            "(IRQ0) through the 8259A ...\n");
                apic_printk(APIC_QUIET, KERN_INFO
                            "..... (found apic %d pin %d) ...\n", apic2, pin2);
                /*
                 * legacy devices should be connected to IO APIC #0
                 */
                replace_pin_at_irq_node(cfg, node, apic1, pin1, apic2, pin2);
                setup_timer_IRQ0_pin(apic2, pin2, cfg->vector);
                legacy_pic->unmask(0);
                if (timer_irq_works()) {
                        apic_printk(APIC_QUIET, KERN_INFO "....... works.\n");
                        timer_through_8259 = 1;
                        goto out;
                }
                /*
                 * Cleanup, just in case ...
                 */
                local_irq_disable();
                legacy_pic->mask(0);
                clear_IO_APIC_pin(apic2, pin2);
                apic_printk(APIC_QUIET, KERN_INFO "....... failed.\n");
        }

        apic_printk(APIC_QUIET, KERN_INFO
                    "...trying to set up timer as Virtual Wire IRQ...\n");

        lapic_register_intr(0);
        apic_write(APIC_LVT0, APIC_DM_FIXED | cfg->vector);     /* Fixed mode */
        legacy_pic->unmask(0);

        if (timer_irq_works()) {
                apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
                goto out;
        }
        local_irq_disable();
        legacy_pic->mask(0);
        apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | cfg->vector);
        apic_printk(APIC_QUIET, KERN_INFO "..... failed.\n");

        apic_printk(APIC_QUIET, KERN_INFO
                    "...trying to set up timer as ExtINT IRQ...\n");

        legacy_pic->init(0);
        legacy_pic->make_irq(0);
        apic_write(APIC_LVT0, APIC_DM_EXTINT);

        unlock_ExtINT_logic();

        if (timer_irq_works()) {
                apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
                goto out;
        }
        local_irq_disable();
        apic_printk(APIC_QUIET, KERN_INFO "..... failed :(.\n");
        if (x2apic_preenabled)
                apic_printk(APIC_QUIET, KERN_INFO
                            "Perhaps problem with the pre-enabled x2apic mode\n"
                            "Try booting with x2apic and interrupt-remapping disabled in the bios.\n");
        panic("IO-APIC + timer doesn't work!  Boot with apic=debug and send a "
                "report.  Then try booting with the 'noapic' option.\n");
out:
        local_irq_restore(flags);
}

/*
 * Traditionally ISA IRQ2 is the cascade IRQ, and is not available
 * to devices.  However there may be an I/O APIC pin available for
 * this interrupt regardless.  The pin may be left unconnected, but
 * typically it will be reused as an ExtINT cascade interrupt for
 * the master 8259A.  In the MPS case such a pin will normally be
 * reported as an ExtINT interrupt in the MP table.  With ACPI
 * there is no provision for ExtINT interrupts, and in the absence
 * of an override it would be treated as an ordinary ISA I/O APIC
 * interrupt, that is edge-triggered and unmasked by default.  We
 * used to do this, but it caused problems on some systems because
 * of the NMI watchdog and sometimes IRQ0 of the 8254 timer using
 * the same ExtINT cascade interrupt to drive the local APIC of the
 * bootstrap processor.  Therefore we refrain from routing IRQ2 to
 * the I/O APIC in all cases now.  No actual device should request
 * it anyway.  --macro
 */
#define PIC_IRQS        (1UL << PIC_CASCADE_IR)

void __init setup_IO_APIC(void)
{

        /*
         * calling enable_IO_APIC() is moved to setup_local_APIC for BP
         */
        io_apic_irqs = legacy_pic->nr_legacy_irqs ? ~PIC_IRQS : ~0UL;

        apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n");
        /*
         * Set up IO-APIC IRQ routing.
         */
        x86_init.mpparse.setup_ioapic_ids();

        sync_Arb_IDs();
        setup_IO_APIC_irqs();
        init_IO_APIC_traps();
        if (legacy_pic->nr_legacy_irqs)
                check_timer();
}

/*
 *      Called after all the initialization is done. If we didn't find any
 *      APIC bugs then we can allow the modify fast path
 */

static int __init io_apic_bug_finalize(void)
{
        if (sis_apic_bug == -1)
                sis_apic_bug = 0;
        return 0;
}

late_initcall(io_apic_bug_finalize);

static void resume_ioapic_id(int ioapic_idx)
{
        unsigned long flags;
        union IO_APIC_reg_00 reg_00;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        reg_00.raw = io_apic_read(ioapic_idx, 0);
        if (reg_00.bits.ID != mpc_ioapic_id(ioapic_idx)) {
                reg_00.bits.ID = mpc_ioapic_id(ioapic_idx);
                io_apic_write(ioapic_idx, 0, reg_00.raw);
        }
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

static void ioapic_resume(void)
{
        int ioapic_idx;

        for (ioapic_idx = nr_ioapics - 1; ioapic_idx >= 0; ioapic_idx--)
                resume_ioapic_id(ioapic_idx);

        restore_ioapic_entries();
}

static struct syscore_ops ioapic_syscore_ops = {
        .suspend = save_ioapic_entries,
        .resume = ioapic_resume,
};

static int __init ioapic_init_ops(void)
{
        register_syscore_ops(&ioapic_syscore_ops);

        return 0;
}

device_initcall(ioapic_init_ops);

/*
 * Dynamic irq allocate and deallocation
 */
unsigned int __create_irqs(unsigned int from, unsigned int count, int node)
{
        struct irq_cfg **cfg;
        unsigned long flags;
        int irq, i;

        if (from < nr_irqs_gsi)
                from = nr_irqs_gsi;

        cfg = kzalloc_node(count * sizeof(cfg[0]), GFP_KERNEL, node);
        if (!cfg)
                return 0;

        irq = alloc_irqs_from(from, count, node);
        if (irq < 0)
                goto out_cfgs;

        for (i = 0; i < count; i++) {
                cfg[i] = alloc_irq_cfg(irq + i, node);
                if (!cfg[i])
                        goto out_irqs;
        }

        raw_spin_lock_irqsave(&vector_lock, flags);
        for (i = 0; i < count; i++)
                if (__assign_irq_vector(irq + i, cfg[i], apic->target_cpus()))
                        goto out_vecs;
        raw_spin_unlock_irqrestore(&vector_lock, flags);

        for (i = 0; i < count; i++) {
                irq_set_chip_data(irq + i, cfg[i]);
                irq_clear_status_flags(irq + i, IRQ_NOREQUEST);
        }

        kfree(cfg);
        return irq;

out_vecs:
        for (i--; i >= 0; i--)
                __clear_irq_vector(irq + i, cfg[i]);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
out_irqs:
        for (i = 0; i < count; i++)
                free_irq_at(irq + i, cfg[i]);
out_cfgs:
        kfree(cfg);
        return 0;
}

unsigned int create_irq_nr(unsigned int from, int node)
{
        return __create_irqs(from, 1, node);
}

int create_irq(void)
{
        int node = cpu_to_node(0);
        unsigned int irq_want;
        int irq;

        irq_want = nr_irqs_gsi;
        irq = create_irq_nr(irq_want, node);

        if (irq == 0)
                irq = -1;

        return irq;
}

void destroy_irq(unsigned int irq)
{
        struct irq_cfg *cfg = irq_get_chip_data(irq);
        unsigned long flags;

        irq_set_status_flags(irq, IRQ_NOREQUEST|IRQ_NOPROBE);

        free_remapped_irq(irq);

        raw_spin_lock_irqsave(&vector_lock, flags);
        __clear_irq_vector(irq, cfg);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        free_irq_at(irq, cfg);
}

void destroy_irqs(unsigned int irq, unsigned int count)
{
        unsigned int i;

        for (i = 0; i < count; i++)
                destroy_irq(irq + i);
}

/*
 * MSI message composition
 */
void native_compose_msi_msg(struct pci_dev *pdev,
                            unsigned int irq, unsigned int dest,
                            struct msi_msg *msg, u8 hpet_id)
{
        struct irq_cfg *cfg = irq_cfg(irq);

        msg->address_hi = MSI_ADDR_BASE_HI;

        if (x2apic_enabled())
                msg->address_hi |= MSI_ADDR_EXT_DEST_ID(dest);

        msg->address_lo =
                MSI_ADDR_BASE_LO |
                ((apic->irq_dest_mode == 0) ?
                        MSI_ADDR_DEST_MODE_PHYSICAL:
                        MSI_ADDR_DEST_MODE_LOGICAL) |
                ((apic->irq_delivery_mode != dest_LowestPrio) ?
                        MSI_ADDR_REDIRECTION_CPU:
                        MSI_ADDR_REDIRECTION_LOWPRI) |
                MSI_ADDR_DEST_ID(dest);

        msg->data =
                MSI_DATA_TRIGGER_EDGE |
                MSI_DATA_LEVEL_ASSERT |
                ((apic->irq_delivery_mode != dest_LowestPrio) ?
                        MSI_DATA_DELIVERY_FIXED:
                        MSI_DATA_DELIVERY_LOWPRI) |
                MSI_DATA_VECTOR(cfg->vector);
}

#ifdef CONFIG_PCI_MSI
static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq,
                           struct msi_msg *msg, u8 hpet_id)
{
        struct irq_cfg *cfg;
        int err;
        unsigned dest;

        if (disable_apic)
                return -ENXIO;

        cfg = irq_cfg(irq);
        err = assign_irq_vector(irq, cfg, apic->target_cpus());
        if (err)
                return err;

        err = apic->cpu_mask_to_apicid_and(cfg->domain,
                                           apic->target_cpus(), &dest);
        if (err)
                return err;

        x86_msi.compose_msi_msg(pdev, irq, dest, msg, hpet_id);

        return 0;
}

static int
msi_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
{
        struct irq_cfg *cfg = data->chip_data;
        struct msi_msg msg;
        unsigned int dest;

        if (__ioapic_set_affinity(data, mask, &dest))
                return -1;

        __get_cached_msi_msg(data->msi_desc, &msg);

        msg.data &= ~MSI_DATA_VECTOR_MASK;
        msg.data |= MSI_DATA_VECTOR(cfg->vector);
        msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK;
        msg.address_lo |= MSI_ADDR_DEST_ID(dest);

        __write_msi_msg(data->msi_desc, &msg);

        return IRQ_SET_MASK_OK_NOCOPY;
}

/*
 * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
 * which implement the MSI or MSI-X Capability Structure.
 */
static struct irq_chip msi_chip = {
        .name                   = "PCI-MSI",
        .irq_unmask             = unmask_msi_irq,
        .irq_mask               = mask_msi_irq,
        .irq_ack                = ack_apic_edge,
        .irq_set_affinity       = msi_set_affinity,
        .irq_retrigger          = ioapic_retrigger_irq,
};

int setup_msi_irq(struct pci_dev *dev, struct msi_desc *msidesc,
                  unsigned int irq_base, unsigned int irq_offset)
{
        struct irq_chip *chip = &msi_chip;
        struct msi_msg msg;
        unsigned int irq = irq_base + irq_offset;
        int ret;

        ret = msi_compose_msg(dev, irq, &msg, -1);
        if (ret < 0)
                return ret;

        irq_set_msi_desc_off(irq_base, irq_offset, msidesc);

        /*
         * MSI-X message is written per-IRQ, the offset is always 0.
         * MSI message denotes a contiguous group of IRQs, written for 0th IRQ.
         */
        if (!irq_offset)
                write_msi_msg(irq, &msg);

        setup_remapped_irq(irq, irq_get_chip_data(irq), chip);

        irq_set_chip_and_handler_name(irq, chip, handle_edge_irq, "edge");

        dev_printk(KERN_DEBUG, &dev->dev, "irq %d for MSI/MSI-X\n", irq);

        return 0;
}

int native_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
        unsigned int irq, irq_want;
        struct msi_desc *msidesc;
        int node, ret;

        /* Multiple MSI vectors only supported with interrupt remapping */
        if (type == PCI_CAP_ID_MSI && nvec > 1)
                return 1;

        node = dev_to_node(&dev->dev);
        irq_want = nr_irqs_gsi;
        list_for_each_entry(msidesc, &dev->msi_list, list) {
                irq = create_irq_nr(irq_want, node);
                if (irq == 0)
                        return -ENOSPC;

                irq_want = irq + 1;

                ret = setup_msi_irq(dev, msidesc, irq, 0);
                if (ret < 0)
                        goto error;
        }
        return 0;

error:
        destroy_irq(irq);
        return ret;
}

void native_teardown_msi_irq(unsigned int irq)
{
        destroy_irq(irq);
}

#ifdef CONFIG_DMAR_TABLE
static int
dmar_msi_set_affinity(struct irq_data *data, const struct cpumask *mask,
                      bool force)
{
        struct irq_cfg *cfg = data->chip_data;
        unsigned int dest, irq = data->irq;
        struct msi_msg msg;

        if (__ioapic_set_affinity(data, mask, &dest))
                return -1;

        dmar_msi_read(irq, &msg);

        msg.data &= ~MSI_DATA_VECTOR_MASK;
        msg.data |= MSI_DATA_VECTOR(cfg->vector);
        msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK;
        msg.address_lo |= MSI_ADDR_DEST_ID(dest);
        msg.address_hi = MSI_ADDR_BASE_HI | MSI_ADDR_EXT_DEST_ID(dest);

        dmar_msi_write(irq, &msg);

        return IRQ_SET_MASK_OK_NOCOPY;
}

static struct irq_chip dmar_msi_type = {
        .name                   = "DMAR_MSI",
        .irq_unmask             = dmar_msi_unmask,
        .irq_mask               = dmar_msi_mask,
        .irq_ack                = ack_apic_edge,
        .irq_set_affinity       = dmar_msi_set_affinity,
        .irq_retrigger          = ioapic_retrigger_irq,
};

int arch_setup_dmar_msi(unsigned int irq)
{
        int ret;
        struct msi_msg msg;

        ret = msi_compose_msg(NULL, irq, &msg, -1);
        if (ret < 0)
                return ret;
        dmar_msi_write(irq, &msg);
        irq_set_chip_and_handler_name(irq, &dmar_msi_type, handle_edge_irq,
                                      "edge");
        return 0;
}
#endif

#ifdef CONFIG_HPET_TIMER

static int hpet_msi_set_affinity(struct irq_data *data,
                                 const struct cpumask *mask, bool force)
{
        struct irq_cfg *cfg = data->chip_data;
        struct msi_msg msg;
        unsigned int dest;

        if (__ioapic_set_affinity(data, mask, &dest))
                return -1;

        hpet_msi_read(data->handler_data, &msg);

        msg.data &= ~MSI_DATA_VECTOR_MASK;
        msg.data |= MSI_DATA_VECTOR(cfg->vector);
        msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK;
        msg.address_lo |= MSI_ADDR_DEST_ID(dest);

        hpet_msi_write(data->handler_data, &msg);

        return IRQ_SET_MASK_OK_NOCOPY;
}

static struct irq_chip hpet_msi_type = {
        .name = "HPET_MSI",
        .irq_unmask = hpet_msi_unmask,
        .irq_mask = hpet_msi_mask,
        .irq_ack = ack_apic_edge,
        .irq_set_affinity = hpet_msi_set_affinity,
        .irq_retrigger = ioapic_retrigger_irq,
};

int default_setup_hpet_msi(unsigned int irq, unsigned int id)
{
        struct irq_chip *chip = &hpet_msi_type;
        struct msi_msg msg;
        int ret;

        ret = msi_compose_msg(NULL, irq, &msg, id);
        if (ret < 0)
                return ret;

        hpet_msi_write(irq_get_handler_data(irq), &msg);
        irq_set_status_flags(irq, IRQ_MOVE_PCNTXT);
        setup_remapped_irq(irq, irq_get_chip_data(irq), chip);

        irq_set_chip_and_handler_name(irq, chip, handle_edge_irq, "edge");
        return 0;
}
#endif

#endif /* CONFIG_PCI_MSI */
/*
 * Hypertransport interrupt support
 */
#ifdef CONFIG_HT_IRQ

static void target_ht_irq(unsigned int irq, unsigned int dest, u8 vector)
{
        struct ht_irq_msg msg;
        fetch_ht_irq_msg(irq, &msg);

        msg.address_lo &= ~(HT_IRQ_LOW_VECTOR_MASK | HT_IRQ_LOW_DEST_ID_MASK);
        msg.address_hi &= ~(HT_IRQ_HIGH_DEST_ID_MASK);

        msg.address_lo |= HT_IRQ_LOW_VECTOR(vector) | HT_IRQ_LOW_DEST_ID(dest);
        msg.address_hi |= HT_IRQ_HIGH_DEST_ID(dest);

        write_ht_irq_msg(irq, &msg);
}

static int
ht_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
{
        struct irq_cfg *cfg = data->chip_data;
        unsigned int dest;

        if (__ioapic_set_affinity(data, mask, &dest))
                return -1;

        target_ht_irq(data->irq, dest, cfg->vector);
        return IRQ_SET_MASK_OK_NOCOPY;
}

static struct irq_chip ht_irq_chip = {
        .name                   = "PCI-HT",
        .irq_mask               = mask_ht_irq,
        .irq_unmask             = unmask_ht_irq,
        .irq_ack                = ack_apic_edge,
        .irq_set_affinity       = ht_set_affinity,
        .irq_retrigger          = ioapic_retrigger_irq,
};

int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
{
        struct irq_cfg *cfg;
        struct ht_irq_msg msg;
        unsigned dest;
        int err;

        if (disable_apic)
                return -ENXIO;

        cfg = irq_cfg(irq);
        err = assign_irq_vector(irq, cfg, apic->target_cpus());
        if (err)
                return err;

        err = apic->cpu_mask_to_apicid_and(cfg->domain,
                                           apic->target_cpus(), &dest);
        if (err)
                return err;

        msg.address_hi = HT_IRQ_HIGH_DEST_ID(dest);

        msg.address_lo =
                HT_IRQ_LOW_BASE |
                HT_IRQ_LOW_DEST_ID(dest) |
                HT_IRQ_LOW_VECTOR(cfg->vector) |
                ((apic->irq_dest_mode == 0) ?
                        HT_IRQ_LOW_DM_PHYSICAL :
                        HT_IRQ_LOW_DM_LOGICAL) |
                HT_IRQ_LOW_RQEOI_EDGE |
                ((apic->irq_delivery_mode != dest_LowestPrio) ?
                        HT_IRQ_LOW_MT_FIXED :
                        HT_IRQ_LOW_MT_ARBITRATED) |
                HT_IRQ_LOW_IRQ_MASKED;

        write_ht_irq_msg(irq, &msg);

        irq_set_chip_and_handler_name(irq, &ht_irq_chip,
                                      handle_edge_irq, "edge");

        dev_printk(KERN_DEBUG, &dev->dev, "irq %d for HT\n", irq);

        return 0;
}
#endif /* CONFIG_HT_IRQ */

static int
io_apic_setup_irq_pin(unsigned int irq, int node, struct io_apic_irq_attr *attr)
{
        struct irq_cfg *cfg = alloc_irq_and_cfg_at(irq, node);
        int ret;

        if (!cfg)
                return -EINVAL;
        ret = __add_pin_to_irq_node(cfg, node, attr->ioapic, attr->ioapic_pin);
        if (!ret)
                setup_ioapic_irq(irq, cfg, attr);
        return ret;
}

int io_apic_setup_irq_pin_once(unsigned int irq, int node,
                               struct io_apic_irq_attr *attr)
{
        unsigned int ioapic_idx = attr->ioapic, pin = attr->ioapic_pin;
        int ret;
        struct IO_APIC_route_entry orig_entry;

        /* Avoid redundant programming */
        if (test_bit(pin, ioapics[ioapic_idx].pin_programmed)) {
                pr_debug("Pin %d-%d already programmed\n", mpc_ioapic_id(ioapic_idx), pin);
                orig_entry = ioapic_read_entry(attr->ioapic, pin);
                if (attr->trigger == orig_entry.trigger && attr->polarity == orig_entry.polarity)
                        return 0;
                return -EBUSY;
        }
        ret = io_apic_setup_irq_pin(irq, node, attr);
        if (!ret)
                set_bit(pin, ioapics[ioapic_idx].pin_programmed);
        return ret;
}

static int __init io_apic_get_redir_entries(int ioapic)
{
        union IO_APIC_reg_01    reg_01;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        reg_01.raw = io_apic_read(ioapic, 1);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        /* The register returns the maximum index redir index
         * supported, which is one less than the total number of redir
         * entries.
         */
        return reg_01.bits.entries + 1;
}

static void __init probe_nr_irqs_gsi(void)
{
        int nr;

        nr = gsi_top + NR_IRQS_LEGACY;
        if (nr > nr_irqs_gsi)
                nr_irqs_gsi = nr;

        printk(KERN_DEBUG "nr_irqs_gsi: %d\n", nr_irqs_gsi);
}

int get_nr_irqs_gsi(void)
{
        return nr_irqs_gsi;
}

int __init arch_probe_nr_irqs(void)
{
        int nr;

        if (nr_irqs > (NR_VECTORS * nr_cpu_ids))
                nr_irqs = NR_VECTORS * nr_cpu_ids;

        nr = nr_irqs_gsi + 8 * nr_cpu_ids;
#if defined(CONFIG_PCI_MSI) || defined(CONFIG_HT_IRQ)
        /*
         * for MSI and HT dyn irq
         */
        nr += nr_irqs_gsi * 16;
#endif
        if (nr < nr_irqs)
                nr_irqs = nr;

        return NR_IRQS_LEGACY;
}

int io_apic_set_pci_routing(struct device *dev, int irq,
                            struct io_apic_irq_attr *irq_attr)
{
        int node;

        if (!IO_APIC_IRQ(irq)) {
                apic_printk(APIC_QUIET,KERN_ERR "IOAPIC[%d]: Invalid reference to IRQ 0\n",
                            irq_attr->ioapic);
                return -EINVAL;
        }

        node = dev ? dev_to_node(dev) : cpu_to_node(0);

        return io_apic_setup_irq_pin_once(irq, node, irq_attr);
}

#ifdef CONFIG_X86_32
static int __init io_apic_get_unique_id(int ioapic, int apic_id)
{
        union IO_APIC_reg_00 reg_00;
        static physid_mask_t apic_id_map = PHYSID_MASK_NONE;
        physid_mask_t tmp;
        unsigned long flags;
        int i = 0;

        /*
         * The P4 platform supports up to 256 APIC IDs on two separate APIC
         * buses (one for LAPICs, one for IOAPICs), where predecessors only
         * supports up to 16 on one shared APIC bus.
         *
         * TBD: Expand LAPIC/IOAPIC support on P4-class systems to take full
         *      advantage of new APIC bus architecture.
         */

        if (physids_empty(apic_id_map))
                apic->ioapic_phys_id_map(&phys_cpu_present_map, &apic_id_map);

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        reg_00.raw = io_apic_read(ioapic, 0);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        if (apic_id >= get_physical_broadcast()) {
                printk(KERN_WARNING "IOAPIC[%d]: Invalid apic_id %d, trying "
                        "%d\n", ioapic, apic_id, reg_00.bits.ID);
                apic_id = reg_00.bits.ID;
        }

        /*
         * Every APIC in a system must have a unique ID or we get lots of nice
         * 'stuck on smp_invalidate_needed IPI wait' messages.
         */
        if (apic->check_apicid_used(&apic_id_map, apic_id)) {

                for (i = 0; i < get_physical_broadcast(); i++) {
                        if (!apic->check_apicid_used(&apic_id_map, i))
                                break;
                }

                if (i == get_physical_broadcast())
                        panic("Max apic_id exceeded!\n");

                printk(KERN_WARNING "IOAPIC[%d]: apic_id %d already used, "
                        "trying %d\n", ioapic, apic_id, i);

                apic_id = i;
        }

        apic->apicid_to_cpu_present(apic_id, &tmp);
        physids_or(apic_id_map, apic_id_map, tmp);

        if (reg_00.bits.ID != apic_id) {
                reg_00.bits.ID = apic_id;

                raw_spin_lock_irqsave(&ioapic_lock, flags);
                io_apic_write(ioapic, 0, reg_00.raw);
                reg_00.raw = io_apic_read(ioapic, 0);
                raw_spin_unlock_irqrestore(&ioapic_lock, flags);

                /* Sanity check */
                if (reg_00.bits.ID != apic_id) {
                        pr_err("IOAPIC[%d]: Unable to change apic_id!\n",
                               ioapic);
                        return -1;
                }
        }

        apic_printk(APIC_VERBOSE, KERN_INFO
                        "IOAPIC[%d]: Assigned apic_id %d\n", ioapic, apic_id);

        return apic_id;
}

static u8 __init io_apic_unique_id(u8 id)
{
        if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
            !APIC_XAPIC(apic_version[boot_cpu_physical_apicid]))
                return io_apic_get_unique_id(nr_ioapics, id);
        else
                return id;
}
#else
static u8 __init io_apic_unique_id(u8 id)
{
        int i;
        DECLARE_BITMAP(used, 256);

        bitmap_zero(used, 256);
        for (i = 0; i < nr_ioapics; i++) {
                __set_bit(mpc_ioapic_id(i), used);
        }
        if (!test_bit(id, used))
                return id;
        return find_first_zero_bit(used, 256);
}
#endif

static int __init io_apic_get_version(int ioapic)
{
        union IO_APIC_reg_01    reg_01;
        unsigned long flags;

        raw_spin_lock_irqsave(&ioapic_lock, flags);
        reg_01.raw = io_apic_read(ioapic, 1);
        raw_spin_unlock_irqrestore(&ioapic_lock, flags);

        return reg_01.bits.version;
}

int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity)
{
        int ioapic, pin, idx;

        if (skip_ioapic_setup)
                return -1;

        ioapic = mp_find_ioapic(gsi);
        if (ioapic < 0)
                return -1;

        pin = mp_find_ioapic_pin(ioapic, gsi);
        if (pin < 0)
                return -1;

        idx = find_irq_entry(ioapic, pin, mp_INT);
        if (idx < 0)
                return -1;

        *trigger = irq_trigger(idx);
        *polarity = irq_polarity(idx);
        return 0;
}

/*
 * This function currently is only a helper for the i386 smp boot process where
 * we need to reprogram the ioredtbls to cater for the cpus which have come online
 * so mask in all cases should simply be apic->target_cpus()
 */
#ifdef CONFIG_SMP
void __init setup_ioapic_dest(void)
{
        int pin, ioapic, irq, irq_entry;
        const struct cpumask *mask;
        struct irq_data *idata;

        if (skip_ioapic_setup == 1)
                return;

        for (ioapic = 0; ioapic < nr_ioapics; ioapic++)
        for (pin = 0; pin < ioapics[ioapic].nr_registers; pin++) {
                irq_entry = find_irq_entry(ioapic, pin, mp_INT);
                if (irq_entry == -1)
                        continue;
                irq = pin_2_irq(irq_entry, ioapic, pin);

                if ((ioapic > 0) && (irq > 16))
                        continue;

                idata = irq_get_irq_data(irq);

                /*
                 * Honour affinities which have been set in early boot
                 */
                if (!irqd_can_balance(idata) || irqd_affinity_was_set(idata))
                        mask = idata->affinity;
                else
                        mask = apic->target_cpus();

                x86_io_apic_ops.set_affinity(idata, mask, false);
        }

}
#endif

#define IOAPIC_RESOURCE_NAME_SIZE 11

static struct resource *ioapic_resources;

static struct resource * __init ioapic_setup_resources(int nr_ioapics)
{
        unsigned long n;
        struct resource *res;
        char *mem;
        int i;

        if (nr_ioapics <= 0)
                return NULL;

        n = IOAPIC_RESOURCE_NAME_SIZE + sizeof(struct resource);
        n *= nr_ioapics;

        mem = alloc_bootmem(n);
        res = (void *)mem;

        mem += sizeof(struct resource) * nr_ioapics;

        for (i = 0; i < nr_ioapics; i++) {
                res[i].name = mem;
                res[i].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
                snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i);
                mem += IOAPIC_RESOURCE_NAME_SIZE;
        }

        ioapic_resources = res;

        return res;
}

void __init native_io_apic_init_mappings(void)
{
        unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
        struct resource *ioapic_res;
        int i;

        ioapic_res = ioapic_setup_resources(nr_ioapics);
        for (i = 0; i < nr_ioapics; i++) {
                if (smp_found_config) {
                        ioapic_phys = mpc_ioapic_addr(i);
#ifdef CONFIG_X86_32
                        if (!ioapic_phys) {
                                printk(KERN_ERR
                                       "WARNING: bogus zero IO-APIC "
                                       "address found in MPTABLE, "
                                       "disabling IO/APIC support!\n");
                                smp_found_config = 0;
                                skip_ioapic_setup = 1;
                                goto fake_ioapic_page;
                        }
#endif
                } else {
#ifdef CONFIG_X86_32
fake_ioapic_page:
#endif
                        ioapic_phys = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
                        ioapic_phys = __pa(ioapic_phys);
                }
                set_fixmap_nocache(idx, ioapic_phys);
                apic_printk(APIC_VERBOSE, "mapped IOAPIC to %08lx (%08lx)\n",
                        __fix_to_virt(idx) + (ioapic_phys & ~PAGE_MASK),
                        ioapic_phys);
                idx++;

                ioapic_res->start = ioapic_phys;
                ioapic_res->end = ioapic_phys + IO_APIC_SLOT_SIZE - 1;
                ioapic_res++;
        }

        probe_nr_irqs_gsi();
}

void __init ioapic_insert_resources(void)
{
        int i;
        struct resource *r = ioapic_resources;

        if (!r) {
                if (nr_ioapics > 0)
                        printk(KERN_ERR
                                "IO APIC resources couldn't be allocated.\n");
                return;
        }

        for (i = 0; i < nr_ioapics; i++) {
                insert_resource(&iomem_resource, r);
                r++;
        }
}

int mp_find_ioapic(u32 gsi)
{
        int i = 0;

        if (nr_ioapics == 0)
                return -1;

        /* Find the IOAPIC that manages this GSI. */
        for (i = 0; i < nr_ioapics; i++) {
                struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(i);
                if ((gsi >= gsi_cfg->gsi_base)
                    && (gsi <= gsi_cfg->gsi_end))
                        return i;
        }

        printk(KERN_ERR "ERROR: Unable to locate IOAPIC for GSI %d\n", gsi);
        return -1;
}

int mp_find_ioapic_pin(int ioapic, u32 gsi)
{
        struct mp_ioapic_gsi *gsi_cfg;

        if (WARN_ON(ioapic == -1))
                return -1;

        gsi_cfg = mp_ioapic_gsi_routing(ioapic);
        if (WARN_ON(gsi > gsi_cfg->gsi_end))
                return -1;

        return gsi - gsi_cfg->gsi_base;
}

static __init int bad_ioapic(unsigned long address)
{
        if (nr_ioapics >= MAX_IO_APICS) {
                pr_warn("WARNING: Max # of I/O APICs (%d) exceeded (found %d), skipping\n",
                        MAX_IO_APICS, nr_ioapics);
                return 1;
        }
        if (!address) {
                pr_warn("WARNING: Bogus (zero) I/O APIC address found in table, skipping!\n");
                return 1;
        }
        return 0;
}

static __init int bad_ioapic_register(int idx)
{
        union IO_APIC_reg_00 reg_00;
        union IO_APIC_reg_01 reg_01;
        union IO_APIC_reg_02 reg_02;

        reg_00.raw = io_apic_read(idx, 0);
        reg_01.raw = io_apic_read(idx, 1);
        reg_02.raw = io_apic_read(idx, 2);

        if (reg_00.raw == -1 && reg_01.raw == -1 && reg_02.raw == -1) {
                pr_warn("I/O APIC 0x%x registers return all ones, skipping!\n",
                        mpc_ioapic_addr(idx));
                return 1;
        }

        return 0;
}

void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
{
        int idx = 0;
        int entries;
        struct mp_ioapic_gsi *gsi_cfg;

        if (bad_ioapic(address))
                return;

        idx = nr_ioapics;

        ioapics[idx].mp_config.type = MP_IOAPIC;
        ioapics[idx].mp_config.flags = MPC_APIC_USABLE;
        ioapics[idx].mp_config.apicaddr = address;

        set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);

        if (bad_ioapic_register(idx)) {
                clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
                return;
        }

        ioapics[idx].mp_config.apicid = io_apic_unique_id(id);
        ioapics[idx].mp_config.apicver = io_apic_get_version(idx);

        /*
         * Build basic GSI lookup table to facilitate gsi->io_apic lookups
         * and to prevent reprogramming of IOAPIC pins (PCI GSIs).
         */
        entries = io_apic_get_redir_entries(idx);
        gsi_cfg = mp_ioapic_gsi_routing(idx);
        gsi_cfg->gsi_base = gsi_base;
        gsi_cfg->gsi_end = gsi_base + entries - 1;

        /*
         * The number of IO-APIC IRQ registers (== #pins):
         */
        ioapics[idx].nr_registers = entries;

        if (gsi_cfg->gsi_end >= gsi_top)
                gsi_top = gsi_cfg->gsi_end + 1;

        pr_info("IOAPIC[%d]: apic_id %d, version %d, address 0x%x, GSI %d-%d\n",
                idx, mpc_ioapic_id(idx),
                mpc_ioapic_ver(idx), mpc_ioapic_addr(idx),
                gsi_cfg->gsi_base, gsi_cfg->gsi_end);

        nr_ioapics++;
}

/* Enable IOAPIC early just for system timer */
void __init pre_init_apic_IRQ0(void)
{
        struct io_apic_irq_attr attr = { 0, 0, 0, 0 };

        printk(KERN_INFO "Early APIC setup for system timer0\n");
#ifndef CONFIG_SMP
        physid_set_mask_of_physid(boot_cpu_physical_apicid,
                                         &phys_cpu_present_map);
#endif
        setup_local_APIC();

        io_apic_setup_irq_pin(0, 0, &attr);
        irq_set_chip_and_handler_name(0, &ioapic_chip, handle_edge_irq,
                                      "edge");
}