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io_apic.c

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  • io_apic.c 77.15 KiB
    /*
     *	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
     *
     * Historical information which is worth to be preserved:
     *
     * - SiS APIC rmw bug:
     *
     *	We used to have a workaround for a bug in SiS chips which
     *	required to rewrite the index register for a read-modify-write
     *	operation as the chip lost the index information which was
     *	setup for the read already. We cache the data now, so that
     *	workaround has been removed.
     */
    
    #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/freezer.h>
    #include <linux/kthread.h>
    #include <linux/jiffies.h>	/* time_after() */
    #include <linux/slab.h>
    #include <linux/bootmem.h>
    
    #include <asm/irqdomain.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/setup.h>
    #include <asm/irq_remapping.h>
    #include <asm/hw_irq.h>
    
    #include <asm/apic.h>
    
    #define	for_each_ioapic(idx)		\
    	for ((idx) = 0; (idx) < nr_ioapics; (idx)++)
    #define	for_each_ioapic_reverse(idx)	\
    	for ((idx) = nr_ioapics - 1; (idx) >= 0; (idx)--)
    #define	for_each_pin(idx, pin)		\
    	for ((pin) = 0; (pin) < ioapics[(idx)].nr_registers; (pin)++)
    #define	for_each_ioapic_pin(idx, pin)	\
    	for_each_ioapic((idx))		\
    		for_each_pin((idx), (pin))
    #define for_each_irq_pin(entry, head) \
    	list_for_each_entry(entry, &head, list)
    
    static DEFINE_RAW_SPINLOCK(ioapic_lock);
    static DEFINE_MUTEX(ioapic_mutex);
    static unsigned int ioapic_dynirq_base;
    static int ioapic_initialized;
    
    struct irq_pin_list {
    	struct list_head list;
    	int apic, pin;
    };
    
    struct mp_chip_data {
    	struct list_head irq_2_pin;
    	struct IO_APIC_route_entry entry;
    	int trigger;
    	int polarity;
    	u32 count;
    	bool isa_irq;
    };
    
    struct mp_ioapic_gsi {
    	u32 gsi_base;
    	u32 gsi_end;
    };
    
    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;
    	struct ioapic_domain_cfg irqdomain_cfg;
    	struct irq_domain *irqdomain;
    	struct resource *iomem_res;
    } 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;
    }
    
    static inline struct mp_ioapic_gsi *mp_ioapic_gsi_routing(int ioapic_idx)
    {
    	return &ioapics[ioapic_idx].gsi_config;
    }
    
    static inline int mp_ioapic_pin_count(int ioapic)
    {
    	struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(ioapic);
    
    	return gsi_cfg->gsi_end - gsi_cfg->gsi_base + 1;
    }
    
    static inline u32 mp_pin_to_gsi(int ioapic, int pin)
    {
    	return mp_ioapic_gsi_routing(ioapic)->gsi_base + pin;
    }
    
    static inline bool mp_is_legacy_irq(int irq)
    {
    	return irq >= 0 && irq < nr_legacy_irqs();
    }
    
    /*
     * Initialize all legacy IRQs and all pins on the first IOAPIC
     * if we have legacy interrupt controller. Kernel boot option "pirq="
     * may rely on non-legacy pins on the first IOAPIC.
     */
    static inline int mp_init_irq_at_boot(int ioapic, int irq)
    {
    	if (!nr_legacy_irqs())
    		return 0;
    
    	return ioapic == 0 || mp_is_legacy_irq(irq);
    }
    
    static inline struct irq_domain *mp_ioapic_irqdomain(int ioapic)
    {
    	return ioapics[ioapic].irqdomain;
    }
    
    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;
    
    #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);
    
    /* 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");
    }
    
    static void alloc_ioapic_saved_registers(int idx)
    {
    	size_t size;
    
    	if (ioapics[idx].saved_registers)
    		return;
    
    	size = sizeof(struct IO_APIC_route_entry) * ioapics[idx].nr_registers;
    	ioapics[idx].saved_registers = kzalloc(size, GFP_KERNEL);
    	if (!ioapics[idx].saved_registers)
    		pr_err("IOAPIC %d: suspend/resume impossible!\n", idx);
    }
    
    static void free_ioapic_saved_registers(int idx)
    {
    	kfree(ioapics[idx].saved_registers);
    	ioapics[idx].saved_registers = NULL;
    }
    
    int __init arch_early_ioapic_init(void)
    {
    	int i;
    
    	if (!nr_legacy_irqs())
    		io_apic_irqs = ~0UL;
    
    	for_each_ioapic(i)
    		alloc_ioapic_saved_registers(i);
    
    	return 0;
    }
    
    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);
    }
    
    static inline 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);
    }
    
    static void 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);
    }
    
    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 = IOAPIC_MASKED };
    
    	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 mp_chip_data *data,
    				 int node, int apic, int pin)
    {
    	struct irq_pin_list *entry;
    
    	/* don't allow duplicates */
    	for_each_irq_pin(entry, data->irq_2_pin)
    		if (entry->apic == apic && entry->pin == pin)
    			return 0;
    
    	entry = kzalloc_node(sizeof(struct irq_pin_list), GFP_ATOMIC, 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;
    	list_add_tail(&entry->list, &data->irq_2_pin);
    
    	return 0;
    }
    
    static void __remove_pin_from_irq(struct mp_chip_data *data, int apic, int pin)
    {
    	struct irq_pin_list *tmp, *entry;
    
    	list_for_each_entry_safe(entry, tmp, &data->irq_2_pin, list)
    		if (entry->apic == apic && entry->pin == pin) {
    			list_del(&entry->list);
    			kfree(entry);
    			return;
    		}
    }
    
    static void add_pin_to_irq_node(struct mp_chip_data *data,
    				int node, int apic, int pin)
    {
    	if (__add_pin_to_irq_node(data, 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 mp_chip_data *data, int node,
    					   int oldapic, int oldpin,
    					   int newapic, int newpin)
    {
    	struct irq_pin_list *entry;
    
    	for_each_irq_pin(entry, data->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(data, node, newapic, newpin);
    }
    
    static void io_apic_modify_irq(struct mp_chip_data *data,
    			       int mask_and, int mask_or,
    			       void (*final)(struct irq_pin_list *entry))
    {
    	union entry_union eu;
    	struct irq_pin_list *entry;
    
    	eu.entry = data->entry;
    	eu.w1 &= mask_and;
    	eu.w1 |= mask_or;
    	data->entry = eu.entry;
    
    	for_each_irq_pin(entry, data->irq_2_pin) {
    		io_apic_write(entry->apic, 0x10 + 2 * entry->pin, eu.w1);
    		if (final)
    			final(entry);
    	}
    }
    
    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_irq(struct irq_data *irq_data)
    {
    	struct mp_chip_data *data = irq_data->chip_data;
    	unsigned long flags;
    
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	io_apic_modify_irq(data, ~0, IO_APIC_REDIR_MASKED, &io_apic_sync);
    	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
    }
    
    static void __unmask_ioapic(struct mp_chip_data *data)
    {
    	io_apic_modify_irq(data, ~IO_APIC_REDIR_MASKED, 0, NULL);
    }
    
    static void unmask_ioapic_irq(struct irq_data *irq_data)
    {
    	struct mp_chip_data *data = irq_data->chip_data;
    	unsigned long flags;
    
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	__unmask_ioapic(data);
    	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
    }
    
    /*
     * 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.
     */
    static void __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 = IOAPIC_MASKED;
    		entry1.trigger = IOAPIC_EDGE;
    
    		__ioapic_write_entry(apic, pin, entry1);
    
    		/*
    		 * Restore the previous level triggered entry.
    		 */
    		__ioapic_write_entry(apic, pin, entry);
    	}
    }
    
    static void eoi_ioapic_pin(int vector, struct mp_chip_data *data)
    {
    	unsigned long flags;
    	struct irq_pin_list *entry;
    
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	for_each_irq_pin(entry, data->irq_2_pin)
    		__eoi_ioapic_pin(entry->apic, entry->pin, 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 == IOAPIC_UNMASKED) {
    		entry.mask = IOAPIC_MASKED;
    		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 == IOAPIC_EDGE) {
    			entry.trigger = IOAPIC_LEVEL;
    			ioapic_write_entry(apic, pin, entry);
    		}
    		raw_spin_lock_irqsave(&ioapic_lock, flags);
    		__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_each_ioapic_pin(apic, 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_each_ioapic(apic) {
    		if (!ioapics[apic].saved_registers) {
    			err = -ENOMEM;
    			continue;
    		}
    
    		for_each_pin(apic, 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_each_ioapic(apic) {
    		if (!ioapics[apic].saved_registers)
    			continue;
    
    		for_each_pin(apic, pin) {
    			struct IO_APIC_route_entry entry;
    
    			entry = ioapics[apic].saved_registers[pin];
    			if (entry.mask == IOAPIC_UNMASKED) {
    				entry.mask = IOAPIC_MASKED;
    				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_each_ioapic(apic) {
    		if (!ioapics[apic].saved_registers)
    			continue;
    
    		for_each_pin(apic, 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_each_ioapic(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 < 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 active high edge triggered,
     * when listed as conforming in the MP table. */
    
    #define default_ISA_trigger(idx)	(IOAPIC_EDGE)
    #define default_ISA_polarity(idx)	(IOAPIC_POL_HIGH)
    
    /* 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 active low level triggered,
     * when listed as conforming in the MP table. */
    
    #define default_PCI_trigger(idx)	(IOAPIC_LEVEL)
    #define default_PCI_polarity(idx)	(IOAPIC_POL_LOW)
    
    static int irq_polarity(int idx)
    {
    	int bus = mp_irqs[idx].srcbus;
    
    	/*
    	 * Determine IRQ line polarity (high active or low active):
    	 */
    	switch (mp_irqs[idx].irqflag & 0x03) {
    	case 0:
    		/* conforms to spec, ie. bus-type dependent polarity */
    		if (test_bit(bus, mp_bus_not_pci))
    			return default_ISA_polarity(idx);
    		else
    			return default_PCI_polarity(idx);
    	case 1:
    		return IOAPIC_POL_HIGH;
    	case 2:
    		pr_warn("IOAPIC: Invalid polarity: 2, defaulting to low\n");
    	case 3:
    	default: /* Pointless default required due to do gcc stupidity */
    		return IOAPIC_POL_LOW;
    	}
    }
    
    #ifdef CONFIG_EISA
    static int eisa_irq_trigger(int idx, int bus, int trigger)
    {
    	switch (mp_bus_id_to_type[bus]) {
    	case MP_BUS_PCI:
    	case MP_BUS_ISA:
    		return trigger;
    	case MP_BUS_EISA:
    		return default_EISA_trigger(idx);
    	}
    	pr_warn("IOAPIC: Invalid srcbus: %d defaulting to level\n", bus);
    	return IOAPIC_LEVEL;
    }
    #else
    static inline int eisa_irq_trigger(int idx, int bus, int trigger)
    {
    	return trigger;
    }
    #endif
    
    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) & 0x03) {
    	case 0:
    		/* conforms to spec, ie. bus-type dependent trigger mode */
    		if (test_bit(bus, mp_bus_not_pci))
    			trigger = default_ISA_trigger(idx);
    		else
    			trigger = default_PCI_trigger(idx);
    		/* Take EISA into account */
    		return eisa_irq_trigger(idx, bus, trigger);
    	case 1:
    		return IOAPIC_EDGE;
    	case 2:
    		pr_warn("IOAPIC: Invalid trigger mode 2 defaulting to level\n");
    	case 3:
    	default: /* Pointless default required due to do gcc stupidity */
    		return IOAPIC_LEVEL;
    	}
    }
    
    void ioapic_set_alloc_attr(struct irq_alloc_info *info, int node,
    			   int trigger, int polarity)
    {
    	init_irq_alloc_info(info, NULL);
    	info->type = X86_IRQ_ALLOC_TYPE_IOAPIC;
    	info->ioapic_node = node;
    	info->ioapic_trigger = trigger;
    	info->ioapic_polarity = polarity;
    	info->ioapic_valid = 1;
    }
    
    #ifndef CONFIG_ACPI
    int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
    #endif
    
    static void ioapic_copy_alloc_attr(struct irq_alloc_info *dst,
    				   struct irq_alloc_info *src,
    				   u32 gsi, int ioapic_idx, int pin)
    {
    	int trigger, polarity;
    
    	copy_irq_alloc_info(dst, src);
    	dst->type = X86_IRQ_ALLOC_TYPE_IOAPIC;
    	dst->ioapic_id = mpc_ioapic_id(ioapic_idx);
    	dst->ioapic_pin = pin;
    	dst->ioapic_valid = 1;
    	if (src && src->ioapic_valid) {
    		dst->ioapic_node = src->ioapic_node;
    		dst->ioapic_trigger = src->ioapic_trigger;
    		dst->ioapic_polarity = src->ioapic_polarity;
    	} else {
    		dst->ioapic_node = NUMA_NO_NODE;
    		if (acpi_get_override_irq(gsi, &trigger, &polarity) >= 0) {
    			dst->ioapic_trigger = trigger;
    			dst->ioapic_polarity = polarity;
    		} else {
    			/*
    			 * PCI interrupts are always active low level
    			 * triggered.
    			 */
    			dst->ioapic_trigger = IOAPIC_LEVEL;
    			dst->ioapic_polarity = IOAPIC_POL_LOW;
    		}
    	}
    }
    
    static int ioapic_alloc_attr_node(struct irq_alloc_info *info)
    {
    	return (info && info->ioapic_valid) ? info->ioapic_node : NUMA_NO_NODE;
    }
    
    static void mp_register_handler(unsigned int irq, unsigned long trigger)
    {
    	irq_flow_handler_t hdl;
    	bool fasteoi;
    
    	if (trigger) {
    		irq_set_status_flags(irq, IRQ_LEVEL);
    		fasteoi = true;
    	} else {
    		irq_clear_status_flags(irq, IRQ_LEVEL);
    		fasteoi = false;
    	}
    
    	hdl = fasteoi ? handle_fasteoi_irq : handle_edge_irq;
    	__irq_set_handler(irq, hdl, 0, fasteoi ? "fasteoi" : "edge");
    }
    
    static bool mp_check_pin_attr(int irq, struct irq_alloc_info *info)
    {
    	struct mp_chip_data *data = irq_get_chip_data(irq);
    
    	/*
    	 * setup_IO_APIC_irqs() programs all legacy IRQs with default trigger
    	 * and polarity attirbutes. So allow the first user to reprogram the
    	 * pin with real trigger and polarity attributes.
    	 */
    	if (irq < nr_legacy_irqs() && data->count == 1) {
    		if (info->ioapic_trigger != data->trigger)
    			mp_register_handler(irq, info->ioapic_trigger);
    		data->entry.trigger = data->trigger = info->ioapic_trigger;
    		data->entry.polarity = data->polarity = info->ioapic_polarity;
    	}
    
    	return data->trigger == info->ioapic_trigger &&
    	       data->polarity == info->ioapic_polarity;
    }
    
    static int alloc_irq_from_domain(struct irq_domain *domain, int ioapic, u32 gsi,
    				 struct irq_alloc_info *info)
    {
    	bool legacy = false;
    	int irq = -1;
    	int type = ioapics[ioapic].irqdomain_cfg.type;
    
    	switch (type) {
    	case IOAPIC_DOMAIN_LEGACY:
    		/*
    		 * Dynamically allocate IRQ number for non-ISA IRQs in the first
    		 * 16 GSIs on some weird platforms.
    		 */
    		if (!ioapic_initialized || gsi >= nr_legacy_irqs())
    			irq = gsi;
    		legacy = mp_is_legacy_irq(irq);
    		break;
    	case IOAPIC_DOMAIN_STRICT:
    		irq = gsi;
    		break;
    	case IOAPIC_DOMAIN_DYNAMIC:
    		break;
    	default:
    		WARN(1, "ioapic: unknown irqdomain type %d\n", type);
    		return -1;
    	}
    
    	return __irq_domain_alloc_irqs(domain, irq, 1,
    				       ioapic_alloc_attr_node(info),
    				       info, legacy);
    }
    
    /*
     * Need special handling for ISA IRQs because there may be multiple IOAPIC pins
     * sharing the same ISA IRQ number and irqdomain only supports 1:1 mapping
     * between IOAPIC pin and IRQ number. A typical IOAPIC has 24 pins, pin 0-15 are
     * used for legacy IRQs and pin 16-23 are used for PCI IRQs (PIRQ A-H).
     * When ACPI is disabled, only legacy IRQ numbers (IRQ0-15) are available, and
     * some BIOSes may use MP Interrupt Source records to override IRQ numbers for
     * PIRQs instead of reprogramming the interrupt routing logic. Thus there may be
     * multiple pins sharing the same legacy IRQ number when ACPI is disabled.
     */
    static int alloc_isa_irq_from_domain(struct irq_domain *domain,
    				     int irq, int ioapic, int pin,
    				     struct irq_alloc_info *info)
    {
    	struct mp_chip_data *data;
    	struct irq_data *irq_data = irq_get_irq_data(irq);
    	int node = ioapic_alloc_attr_node(info);
    
    	/*
    	 * Legacy ISA IRQ has already been allocated, just add pin to
    	 * the pin list assoicated with this IRQ and program the IOAPIC
    	 * entry. The IOAPIC entry
    	 */
    	if (irq_data && irq_data->parent_data) {
    		if (!mp_check_pin_attr(irq, info))
    			return -EBUSY;
    		if (__add_pin_to_irq_node(irq_data->chip_data, node, ioapic,
    					  info->ioapic_pin))
    			return -ENOMEM;
    	} else {
    		irq = __irq_domain_alloc_irqs(domain, irq, 1, node, info, true);
    		if (irq >= 0) {
    			irq_data = irq_domain_get_irq_data(domain, irq);
    			data = irq_data->chip_data;
    			data->isa_irq = true;
    		}
    	}
    
    	return irq;
    }
    
    static int mp_map_pin_to_irq(u32 gsi, int idx, int ioapic, int pin,
    			     unsigned int flags, struct irq_alloc_info *info)
    {
    	int irq;
    	bool legacy = false;
    	struct irq_alloc_info tmp;
    	struct mp_chip_data *data;
    	struct irq_domain *domain = mp_ioapic_irqdomain(ioapic);
    
    	if (!domain)
    		return -ENOSYS;
    
    	if (idx >= 0 && test_bit(mp_irqs[idx].srcbus, mp_bus_not_pci)) {
    		irq = mp_irqs[idx].srcbusirq;
    		legacy = mp_is_legacy_irq(irq);
    	}
    
    	mutex_lock(&ioapic_mutex);
    	if (!(flags & IOAPIC_MAP_ALLOC)) {
    		if (!legacy) {
    			irq = irq_find_mapping(domain, pin);
    			if (irq == 0)
    				irq = -ENOENT;
    		}
    	} else {
    		ioapic_copy_alloc_attr(&tmp, info, gsi, ioapic, pin);
    		if (legacy)
    			irq = alloc_isa_irq_from_domain(domain, irq,
    							ioapic, pin, &tmp);
    		else if ((irq = irq_find_mapping(domain, pin)) == 0)
    			irq = alloc_irq_from_domain(domain, ioapic, gsi, &tmp);
    		else if (!mp_check_pin_attr(irq, &tmp))
    			irq = -EBUSY;
    		if (irq >= 0) {
    			data = irq_get_chip_data(irq);
    			data->count++;
    		}
    	}
    	mutex_unlock(&ioapic_mutex);
    
    	return irq;
    }
    
    static int pin_2_irq(int idx, int ioapic, int pin, unsigned int flags)
    {
    	u32 gsi = mp_pin_to_gsi(ioapic, pin);
    
    	/*
    	 * 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");
    
    #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 {
    				int irq = pirq_entries[pin-16];
    				apic_printk(APIC_VERBOSE, KERN_DEBUG
    						"using PIRQ%d -> IRQ %d\n",
    						pin-16, irq);
    				return irq;
    			}
    		}
    	}
    #endif
    
    	return  mp_map_pin_to_irq(gsi, idx, ioapic, pin, flags, NULL);
    }
    
    int mp_map_gsi_to_irq(u32 gsi, unsigned int flags, struct irq_alloc_info *info)
    {
    	int ioapic, pin, idx;
    
    	ioapic = mp_find_ioapic(gsi);
    	if (ioapic < 0)
    		return -1;
    
    	pin = mp_find_ioapic_pin(ioapic, gsi);
    	idx = find_irq_entry(ioapic, pin, mp_INT);
    	if ((flags & IOAPIC_MAP_CHECK) && idx < 0)
    		return -1;
    
    	return mp_map_pin_to_irq(gsi, idx, ioapic, pin, flags, info);
    }
    
    void mp_unmap_irq(int irq)
    {
    	struct irq_data *irq_data = irq_get_irq_data(irq);
    	struct mp_chip_data *data;
    
    	if (!irq_data || !irq_data->domain)
    		return;
    
    	data = irq_data->chip_data;
    	if (!data || data->isa_irq)
    		return;
    
    	mutex_lock(&ioapic_mutex);
    	if (--data->count == 0)
    		irq_domain_free_irqs(irq, 1);
    	mutex_unlock(&ioapic_mutex);
    }
    
    /*
     * 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)
    {
    	int irq, i, best_ioapic = -1, best_idx = -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;
    		int ioapic_idx, found = 0;
    
    		if (bus != lbus || mp_irqs[i].irqtype != mp_INT ||
    		    slot != ((mp_irqs[i].srcbusirq >> 2) & 0x1f))
    			continue;
    
    		for_each_ioapic(ioapic_idx)
    			if (mpc_ioapic_id(ioapic_idx) == mp_irqs[i].dstapic ||
    			    mp_irqs[i].dstapic == MP_APIC_ALL) {
    				found = 1;
    				break;
    			}
    		if (!found)
    			continue;
    
    		/* Skip ISA IRQs */
    		irq = pin_2_irq(i, ioapic_idx, mp_irqs[i].dstirq, 0);
    		if (irq > 0 && !IO_APIC_IRQ(irq))
    			continue;
    
    		if (pin == (mp_irqs[i].srcbusirq & 3)) {
    			best_idx = i;
    			best_ioapic = ioapic_idx;
    			goto out;
    		}
    
    		/*
    		 * Use the first all-but-pin matching entry as a
    		 * best-guess fuzzy result for broken mptables.
    		 */
    		if (best_idx < 0) {
    			best_idx = i;
    			best_ioapic = ioapic_idx;
    		}
    	}
    	if (best_idx < 0)
    		return -1;
    
    out:
    	return pin_2_irq(best_idx, best_ioapic, mp_irqs[best_idx].dstirq,
    			 IOAPIC_MAP_ALLOC);
    }
    EXPORT_SYMBOL(IO_APIC_get_PCI_irq_vector);
    
    static struct irq_chip ioapic_chip, ioapic_ir_chip;
    
    #ifdef CONFIG_X86_32
    static inline int IO_APIC_irq_trigger(int irq)
    {
    	int apic, idx, pin;
    
    	for_each_ioapic_pin(apic, pin) {
    		idx = find_irq_entry(apic, pin, mp_INT);
    		if ((idx != -1) && (irq == pin_2_irq(idx, apic, pin, 0)))
    			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 __init setup_IO_APIC_irqs(void)
    {
    	unsigned int ioapic, pin;
    	int idx;
    
    	apic_printk(APIC_VERBOSE, KERN_DEBUG "init IO_APIC IRQs\n");
    
    	for_each_ioapic_pin(ioapic, pin) {
    		idx = find_irq_entry(ioapic, pin, mp_INT);
    		if (idx < 0)
    			apic_printk(APIC_VERBOSE,
    				    KERN_DEBUG " apic %d pin %d not connected\n",
    				    mpc_ioapic_id(ioapic), pin);
    		else
    			pin_2_irq(idx, ioapic, pin,
    				  ioapic ? 0 : IOAPIC_MAP_ALLOC);
    	}
    }
    
    void ioapic_zap_locks(void)
    {
    	raw_spin_lock_init(&ioapic_lock);
    }
    
    static void io_apic_print_entries(unsigned int apic, unsigned int nr_entries)
    {
    	int i;
    	char buf[256];
    	struct IO_APIC_route_entry entry;
    	struct IR_IO_APIC_route_entry *ir_entry = (void *)&entry;
    
    	printk(KERN_DEBUG "IOAPIC %d:\n", apic);
    	for (i = 0; i <= nr_entries; i++) {
    		entry = ioapic_read_entry(apic, i);
    		snprintf(buf, sizeof(buf),
    			 " pin%02x, %s, %s, %s, V(%02X), IRR(%1d), S(%1d)",
    			 i,
    			 entry.mask == IOAPIC_MASKED ? "disabled" : "enabled ",
    			 entry.trigger == IOAPIC_LEVEL ? "level" : "edge ",
    			 entry.polarity == IOAPIC_POL_LOW ? "low " : "high",
    			 entry.vector, entry.irr, entry.delivery_status);
    		if (ir_entry->format)
    			printk(KERN_DEBUG "%s, remapped, I(%04X),  Z(%X)\n",
    			       buf, (ir_entry->index << 15) | ir_entry->index,
    			       ir_entry->zero);
    		else
    			printk(KERN_DEBUG "%s, %s, D(%02X), M(%1d)\n",
    			       buf,
    			       entry.dest_mode == IOAPIC_DEST_MODE_LOGICAL ?
    			       "logical " : "physical",
    			       entry.dest, entry.delivery_mode);
    	}
    }
    
    static void __init 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");
    	io_apic_print_entries(ioapic_idx, reg_01.bits.entries);
    }
    
    void __init print_IO_APICs(void)
    {
    	int ioapic_idx;
    	unsigned int irq;
    
    	printk(KERN_DEBUG "number of MP IRQ sources: %d.\n", mp_irq_entries);
    	for_each_ioapic(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_each_ioapic(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;
    		struct irq_chip *chip;
    		struct mp_chip_data *data;
    
    		chip = irq_get_chip(irq);
    		if (chip != &ioapic_chip && chip != &ioapic_ir_chip)
    			continue;
    		data = irq_get_chip_data(irq);
    		if (!data)
    			continue;
    		if (list_empty(&data->irq_2_pin))
    			continue;
    
    		printk(KERN_DEBUG "IRQ%d ", irq);
    		for_each_irq_pin(entry, data->irq_2_pin)
    			pr_cont("-> %d:%d", entry->apic, entry->pin);
    		pr_cont("\n");
    	}
    
    	printk(KERN_INFO ".................................... done.\n");
    }
    
    /* 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, pin;
    
    	if (skip_ioapic_setup)
    		nr_ioapics = 0;
    
    	if (!nr_legacy_irqs() || !nr_ioapics)
    		return;
    
    	for_each_ioapic_pin(apic, pin) {
    		/* See if any of the pins is in ExtINT mode */
    		struct IO_APIC_route_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		= IOAPIC_UNMASKED;
    		entry.trigger		= IOAPIC_EDGE;
    		entry.polarity		= IOAPIC_POL_HIGH;
    		entry.dest_mode		= IOAPIC_DEST_MODE_PHYSICAL;
    		entry.delivery_mode	= dest_ExtINT;
    		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 (!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_each_ioapic(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 < 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;
    }
    
    atomic_t irq_mis_count;
    
    #ifdef CONFIG_GENERIC_PENDING_IRQ
    static bool io_apic_level_ack_pending(struct mp_chip_data *data)
    {
    	struct irq_pin_list *entry;
    	unsigned long flags;
    
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	for_each_irq_pin(entry, data->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)
    {
    	/* If we are moving the irq we need to mask it */
    	if (unlikely(irqd_is_setaffinity_pending(data))) {
    		mask_ioapic_irq(data);
    		return true;
    	}
    	return false;
    }
    
    static inline void ioapic_irqd_unmask(struct irq_data *data, 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(data->chip_data))
    			irq_move_masked_irq(data);
    		unmask_ioapic_irq(data);
    	}
    }
    #else
    static inline bool ioapic_irqd_mask(struct irq_data *data)
    {
    	return false;
    }
    static inline void ioapic_irqd_unmask(struct irq_data *data, bool masked)
    {
    }
    #endif
    
    static void ioapic_ack_level(struct irq_data *irq_data)
    {
    	struct irq_cfg *cfg = irqd_cfg(irq_data);
    	unsigned long v;
    	bool masked;
    	int i;
    
    	irq_complete_move(cfg);
    	masked = ioapic_irqd_mask(irq_data);
    
    	/*
    	 * 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_pin(cfg->vector, irq_data->chip_data);
    	}
    
    	ioapic_irqd_unmask(irq_data, masked);
    }
    
    static void ioapic_ir_ack_level(struct irq_data *irq_data)
    {
    	struct mp_chip_data *data = irq_data->chip_data;
    
    	/*
    	 * Intr-remapping uses pin number as the virtual vector
    	 * in the RTE. Actual vector is programmed in
    	 * intr-remapping table entry. Hence for the io-apic
    	 * EOI we use the pin number.
    	 */
    	ack_APIC_irq();
    	eoi_ioapic_pin(data->entry.vector, data);
    }
    
    static int ioapic_set_affinity(struct irq_data *irq_data,
    			       const struct cpumask *mask, bool force)
    {
    	struct irq_data *parent = irq_data->parent_data;
    	struct mp_chip_data *data = irq_data->chip_data;
    	struct irq_pin_list *entry;
    	struct irq_cfg *cfg;
    	unsigned long flags;
    	int ret;
    
    	ret = parent->chip->irq_set_affinity(parent, mask, force);
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
    		cfg = irqd_cfg(irq_data);
    		data->entry.dest = cfg->dest_apicid;
    		data->entry.vector = cfg->vector;
    		for_each_irq_pin(entry, data->irq_2_pin)
    			__ioapic_write_entry(entry->apic, entry->pin,
    					     data->entry);
    	}
    	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
    
    	return ret;
    }
    
    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		= irq_chip_ack_parent,
    	.irq_eoi		= ioapic_ack_level,
    	.irq_set_affinity	= ioapic_set_affinity,
    	.flags			= IRQCHIP_SKIP_SET_WAKE,
    };
    
    static struct irq_chip ioapic_ir_chip __read_mostly = {
    	.name			= "IR-IO-APIC",
    	.irq_startup		= startup_ioapic_irq,
    	.irq_mask		= mask_ioapic_irq,
    	.irq_unmask		= unmask_ioapic_irq,
    	.irq_ack		= irq_chip_ack_parent,
    	.irq_eoi		= ioapic_ir_ack_level,
    	.irq_set_affinity	= ioapic_set_affinity,
    	.flags			= IRQCHIP_SKIP_SET_WAKE,
    };
    
    static inline void init_IO_APIC_traps(void)
    {
    	struct irq_cfg *cfg;
    	unsigned int irq;
    
    	for_each_active_irq(irq) {
    		cfg = irq_cfg(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 < 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 = IOAPIC_DEST_MODE_PHYSICAL;
    	entry1.mask = IOAPIC_UNMASKED;
    	entry1.dest = hard_smp_processor_id();
    	entry1.delivery_mode = dest_ExtINT;
    	entry1.polarity = entry0.polarity;
    	entry1.trigger = IOAPIC_EDGE;
    	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);
    
    static int mp_alloc_timer_irq(int ioapic, int pin)
    {
    	int irq = -1;
    	struct irq_domain *domain = mp_ioapic_irqdomain(ioapic);
    
    	if (domain) {
    		struct irq_alloc_info info;
    
    		ioapic_set_alloc_attr(&info, NUMA_NO_NODE, 0, 0);
    		info.ioapic_id = mpc_ioapic_id(ioapic);
    		info.ioapic_pin = pin;
    		mutex_lock(&ioapic_mutex);
    		irq = alloc_isa_irq_from_domain(domain, 0, ioapic, pin, &info);
    		mutex_unlock(&ioapic_mutex);
    	}
    
    	return irq;
    }
    
    /*
     * 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_data *irq_data = irq_get_irq_data(0);
    	struct mp_chip_data *data = irq_data->chip_data;
    	struct irq_cfg *cfg = irqd_cfg(irq_data);
    	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);
    
    	/*
    	 * 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) {
    			mp_alloc_timer_irq(apic1, pin1);
    		} else {
    			/*
    			 * for edge trigger, it's already 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_irq(irq_get_chip_data(0));
    		}
    		irq_domain_activate_irq(irq_data);
    		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(data, node, apic1, pin1, apic2, pin2);
    		irq_domain_activate_irq(irq_data);
    		legacy_pic->unmask(0);
    		if (timer_irq_works()) {
    			apic_printk(APIC_QUIET, KERN_INFO "....... works.\n");
    			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 (apic_is_x2apic_enabled())
    		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)
    
    static int mp_irqdomain_create(int ioapic)
    {
    	struct irq_alloc_info info;
    	struct irq_domain *parent;
    	int hwirqs = mp_ioapic_pin_count(ioapic);
    	struct ioapic *ip = &ioapics[ioapic];
    	struct ioapic_domain_cfg *cfg = &ip->irqdomain_cfg;
    	struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(ioapic);
    
    	if (cfg->type == IOAPIC_DOMAIN_INVALID)
    		return 0;
    
    	init_irq_alloc_info(&info, NULL);
    	info.type = X86_IRQ_ALLOC_TYPE_IOAPIC;
    	info.ioapic_id = mpc_ioapic_id(ioapic);
    	parent = irq_remapping_get_ir_irq_domain(&info);
    	if (!parent)
    		parent = x86_vector_domain;
    
    	ip->irqdomain = irq_domain_add_linear(cfg->dev, hwirqs, cfg->ops,
    					      (void *)(long)ioapic);
    	if (!ip->irqdomain)
    		return -ENOMEM;
    
    	ip->irqdomain->parent = parent;
    
    	if (cfg->type == IOAPIC_DOMAIN_LEGACY ||
    	    cfg->type == IOAPIC_DOMAIN_STRICT)
    		ioapic_dynirq_base = max(ioapic_dynirq_base,
    					 gsi_cfg->gsi_end + 1);
    
    	return 0;
    }
    
    static void ioapic_destroy_irqdomain(int idx)
    {
    	if (ioapics[idx].irqdomain) {
    		irq_domain_remove(ioapics[idx].irqdomain);
    		ioapics[idx].irqdomain = NULL;
    	}
    }
    
    void __init setup_IO_APIC(void)
    {
    	int ioapic;
    
    	if (skip_ioapic_setup || !nr_ioapics)
    		return;
    
    	io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL;
    
    	apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n");
    	for_each_ioapic(ioapic)
    		BUG_ON(mp_irqdomain_create(ioapic));
    
    	/*
             * Set up IO-APIC IRQ routing.
             */
    	x86_init.mpparse.setup_ioapic_ids();
    
    	sync_Arb_IDs();
    	setup_IO_APIC_irqs();
    	init_IO_APIC_traps();
    	if (nr_legacy_irqs())
    		check_timer();
    
    	ioapic_initialized = 1;
    }
    
    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_each_ioapic_reverse(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);
    
    static int 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;
    }
    
    unsigned int arch_dynirq_lower_bound(unsigned int from)
    {
    	/*
    	 * dmar_alloc_hwirq() may be called before setup_IO_APIC(), so use
    	 * gsi_top if ioapic_dynirq_base hasn't been initialized yet.
    	 */
    	return ioapic_initialized ? ioapic_dynirq_base : gsi_top;
    }
    
    #ifdef CONFIG_X86_32
    static int 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 io_apic_unique_id(int idx, 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(idx, id);
    	else
    		return id;
    }
    #else
    static u8 io_apic_unique_id(int idx, u8 id)
    {
    	union IO_APIC_reg_00 reg_00;
    	DECLARE_BITMAP(used, 256);
    	unsigned long flags;
    	u8 new_id;
    	int i;
    
    	bitmap_zero(used, 256);
    	for_each_ioapic(i)
    		__set_bit(mpc_ioapic_id(i), used);
    
    	/* Hand out the requested id if available */
    	if (!test_bit(id, used))
    		return id;
    
    	/*
    	 * Read the current id from the ioapic and keep it if
    	 * available.
    	 */
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	reg_00.raw = io_apic_read(idx, 0);
    	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
    	new_id = reg_00.bits.ID;
    	if (!test_bit(new_id, used)) {
    		apic_printk(APIC_VERBOSE, KERN_INFO
    			"IOAPIC[%d]: Using reg apic_id %d instead of %d\n",
    			 idx, new_id, id);
    		return new_id;
    	}
    
    	/*
    	 * Get the next free id and write it to the ioapic.
    	 */
    	new_id = find_first_zero_bit(used, 256);
    	reg_00.bits.ID = new_id;
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	io_apic_write(idx, 0, reg_00.raw);
    	reg_00.raw = io_apic_read(idx, 0);
    	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
    	/* Sanity check */
    	BUG_ON(reg_00.bits.ID != new_id);
    
    	return new_id;
    }
    #endif
    
    static int 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_desc *desc;
    	struct irq_data *idata;
    	struct irq_chip *chip;
    
    	if (skip_ioapic_setup == 1)
    		return;
    
    	for_each_ioapic_pin(ioapic, pin) {
    		irq_entry = find_irq_entry(ioapic, pin, mp_INT);
    		if (irq_entry == -1)
    			continue;
    
    		irq = pin_2_irq(irq_entry, ioapic, pin, 0);
    		if (irq < 0 || !mp_init_irq_at_boot(ioapic, irq))
    			continue;
    
    		desc = irq_to_desc(irq);
    		raw_spin_lock_irq(&desc->lock);
    		idata = irq_desc_get_irq_data(desc);
    
    		/*
    		 * Honour affinities which have been set in early boot
    		 */
    		if (!irqd_can_balance(idata) || irqd_affinity_was_set(idata))
    			mask = irq_data_get_affinity_mask(idata);
    		else
    			mask = apic->target_cpus();
    
    		chip = irq_data_get_irq_chip(idata);
    		/* Might be lapic_chip for irq 0 */
    		if (chip->irq_set_affinity)
    			chip->irq_set_affinity(idata, mask, false);
    		raw_spin_unlock_irq(&desc->lock);
    	}
    }
    #endif
    
    #define IOAPIC_RESOURCE_NAME_SIZE 11
    
    static struct resource *ioapic_resources;
    
    static struct resource * __init ioapic_setup_resources(void)
    {
    	unsigned long n;
    	struct resource *res;
    	char *mem;
    	int i, num = 0;
    
    	for_each_ioapic(i)
    		num++;
    	if (num == 0)
    		return NULL;
    
    	n = IOAPIC_RESOURCE_NAME_SIZE + sizeof(struct resource);
    	n *= num;
    
    	mem = alloc_bootmem(n);
    	res = (void *)mem;
    
    	mem += sizeof(struct resource) * num;
    
    	num = 0;
    	for_each_ioapic(i) {
    		res[num].name = mem;
    		res[num].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
    		snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i);
    		mem += IOAPIC_RESOURCE_NAME_SIZE;
    		num++;
    		ioapics[i].iomem_res = res;
    	}
    
    	ioapic_resources = res;
    
    	return res;
    }
    
    void __init 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();
    	for_each_ioapic(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++;
    	}
    }
    
    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_each_ioapic(i) {
    		insert_resource(&iomem_resource, r);
    		r++;
    	}
    }
    
    int mp_find_ioapic(u32 gsi)
    {
    	int i;
    
    	if (nr_ioapics == 0)
    		return -1;
    
    	/* Find the IOAPIC that manages this GSI. */
    	for_each_ioapic(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 < 0))
    		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 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;
    }
    
    static int find_free_ioapic_entry(void)
    {
    	int idx;
    
    	for (idx = 0; idx < MAX_IO_APICS; idx++)
    		if (ioapics[idx].nr_registers == 0)
    			return idx;
    
    	return MAX_IO_APICS;
    }
    
    /**
     * mp_register_ioapic - Register an IOAPIC device
     * @id:		hardware IOAPIC ID
     * @address:	physical address of IOAPIC register area
     * @gsi_base:	base of GSI associated with the IOAPIC
     * @cfg:	configuration information for the IOAPIC
     */
    int mp_register_ioapic(int id, u32 address, u32 gsi_base,
    		       struct ioapic_domain_cfg *cfg)
    {
    	bool hotplug = !!ioapic_initialized;
    	struct mp_ioapic_gsi *gsi_cfg;
    	int idx, ioapic, entries;
    	u32 gsi_end;
    
    	if (!address) {
    		pr_warn("Bogus (zero) I/O APIC address found, skipping!\n");
    		return -EINVAL;
    	}
    	for_each_ioapic(ioapic)
    		if (ioapics[ioapic].mp_config.apicaddr == address) {
    			pr_warn("address 0x%x conflicts with IOAPIC%d\n",
    				address, ioapic);
    			return -EEXIST;
    		}
    
    	idx = find_free_ioapic_entry();
    	if (idx >= MAX_IO_APICS) {
    		pr_warn("Max # of I/O APICs (%d) exceeded (found %d), skipping\n",
    			MAX_IO_APICS, idx);
    		return -ENOSPC;
    	}
    
    	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 -ENODEV;
    	}
    
    	ioapics[idx].mp_config.apicid = io_apic_unique_id(idx, 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_end = gsi_base + entries - 1;
    	for_each_ioapic(ioapic) {
    		gsi_cfg = mp_ioapic_gsi_routing(ioapic);
    		if ((gsi_base >= gsi_cfg->gsi_base &&
    		     gsi_base <= gsi_cfg->gsi_end) ||
    		    (gsi_end >= gsi_cfg->gsi_base &&
    		     gsi_end <= gsi_cfg->gsi_end)) {
    			pr_warn("GSI range [%u-%u] for new IOAPIC conflicts with GSI[%u-%u]\n",
    				gsi_base, gsi_end,
    				gsi_cfg->gsi_base, gsi_cfg->gsi_end);
    			clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
    			return -ENOSPC;
    		}
    	}
    	gsi_cfg = mp_ioapic_gsi_routing(idx);
    	gsi_cfg->gsi_base = gsi_base;
    	gsi_cfg->gsi_end = gsi_end;
    
    	ioapics[idx].irqdomain = NULL;
    	ioapics[idx].irqdomain_cfg = *cfg;
    
    	/*
    	 * If mp_register_ioapic() is called during early boot stage when
    	 * walking ACPI/SFI/DT tables, it's too early to create irqdomain,
    	 * we are still using bootmem allocator. So delay it to setup_IO_APIC().
    	 */
    	if (hotplug) {
    		if (mp_irqdomain_create(idx)) {
    			clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
    			return -ENOMEM;
    		}
    		alloc_ioapic_saved_registers(idx);
    	}
    
    	if (gsi_cfg->gsi_end >= gsi_top)
    		gsi_top = gsi_cfg->gsi_end + 1;
    	if (nr_ioapics <= idx)
    		nr_ioapics = idx + 1;
    
    	/* Set nr_registers to mark entry present */
    	ioapics[idx].nr_registers = entries;
    
    	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);
    
    	return 0;
    }
    
    int mp_unregister_ioapic(u32 gsi_base)
    {
    	int ioapic, pin;
    	int found = 0;
    
    	for_each_ioapic(ioapic)
    		if (ioapics[ioapic].gsi_config.gsi_base == gsi_base) {
    			found = 1;
    			break;
    		}
    	if (!found) {
    		pr_warn("can't find IOAPIC for GSI %d\n", gsi_base);
    		return -ENODEV;
    	}
    
    	for_each_pin(ioapic, pin) {
    		u32 gsi = mp_pin_to_gsi(ioapic, pin);
    		int irq = mp_map_gsi_to_irq(gsi, 0, NULL);
    		struct mp_chip_data *data;
    
    		if (irq >= 0) {
    			data = irq_get_chip_data(irq);
    			if (data && data->count) {
    				pr_warn("pin%d on IOAPIC%d is still in use.\n",
    					pin, ioapic);
    				return -EBUSY;
    			}
    		}
    	}
    
    	/* Mark entry not present */
    	ioapics[ioapic].nr_registers  = 0;
    	ioapic_destroy_irqdomain(ioapic);
    	free_ioapic_saved_registers(ioapic);
    	if (ioapics[ioapic].iomem_res)
    		release_resource(ioapics[ioapic].iomem_res);
    	clear_fixmap(FIX_IO_APIC_BASE_0 + ioapic);
    	memset(&ioapics[ioapic], 0, sizeof(ioapics[ioapic]));
    
    	return 0;
    }
    
    int mp_ioapic_registered(u32 gsi_base)
    {
    	int ioapic;
    
    	for_each_ioapic(ioapic)
    		if (ioapics[ioapic].gsi_config.gsi_base == gsi_base)
    			return 1;
    
    	return 0;
    }
    
    static void mp_irqdomain_get_attr(u32 gsi, struct mp_chip_data *data,
    				  struct irq_alloc_info *info)
    {
    	if (info && info->ioapic_valid) {
    		data->trigger = info->ioapic_trigger;
    		data->polarity = info->ioapic_polarity;
    	} else if (acpi_get_override_irq(gsi, &data->trigger,
    					 &data->polarity) < 0) {
    		/* PCI interrupts are always active low level triggered. */
    		data->trigger = IOAPIC_LEVEL;
    		data->polarity = IOAPIC_POL_LOW;
    	}
    }
    
    static void mp_setup_entry(struct irq_cfg *cfg, struct mp_chip_data *data,
    			   struct IO_APIC_route_entry *entry)
    {
    	memset(entry, 0, sizeof(*entry));
    	entry->delivery_mode = apic->irq_delivery_mode;
    	entry->dest_mode     = apic->irq_dest_mode;
    	entry->dest	     = cfg->dest_apicid;
    	entry->vector	     = cfg->vector;
    	entry->trigger	     = data->trigger;
    	entry->polarity	     = data->polarity;
    	/*
    	 * Mask level triggered irqs. Edge triggered irqs are masked
    	 * by the irq core code in case they fire.
    	 */
    	if (data->trigger == IOAPIC_LEVEL)
    		entry->mask = IOAPIC_MASKED;
    	else
    		entry->mask = IOAPIC_UNMASKED;
    }
    
    int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq,
    		       unsigned int nr_irqs, void *arg)
    {
    	int ret, ioapic, pin;
    	struct irq_cfg *cfg;
    	struct irq_data *irq_data;
    	struct mp_chip_data *data;
    	struct irq_alloc_info *info = arg;
    	unsigned long flags;
    
    	if (!info || nr_irqs > 1)
    		return -EINVAL;
    	irq_data = irq_domain_get_irq_data(domain, virq);
    	if (!irq_data)
    		return -EINVAL;
    
    	ioapic = mp_irqdomain_ioapic_idx(domain);
    	pin = info->ioapic_pin;
    	if (irq_find_mapping(domain, (irq_hw_number_t)pin) > 0)
    		return -EEXIST;
    
    	data = kzalloc(sizeof(*data), GFP_KERNEL);
    	if (!data)
    		return -ENOMEM;
    
    	info->ioapic_entry = &data->entry;
    	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, info);
    	if (ret < 0) {
    		kfree(data);
    		return ret;
    	}
    
    	INIT_LIST_HEAD(&data->irq_2_pin);
    	irq_data->hwirq = info->ioapic_pin;
    	irq_data->chip = (domain->parent == x86_vector_domain) ?
    			  &ioapic_chip : &ioapic_ir_chip;
    	irq_data->chip_data = data;
    	mp_irqdomain_get_attr(mp_pin_to_gsi(ioapic, pin), data, info);
    
    	cfg = irqd_cfg(irq_data);
    	add_pin_to_irq_node(data, ioapic_alloc_attr_node(info), ioapic, pin);
    
    	local_irq_save(flags);
    	if (info->ioapic_entry)
    		mp_setup_entry(cfg, data, info->ioapic_entry);
    	mp_register_handler(virq, data->trigger);
    	if (virq < nr_legacy_irqs())
    		legacy_pic->mask(virq);
    	local_irq_restore(flags);
    
    	apic_printk(APIC_VERBOSE, KERN_DEBUG
    		    "IOAPIC[%d]: Set routing entry (%d-%d -> 0x%x -> IRQ %d Mode:%i Active:%i Dest:%d)\n",
    		    ioapic, mpc_ioapic_id(ioapic), pin, cfg->vector,
    		    virq, data->trigger, data->polarity, cfg->dest_apicid);
    
    	return 0;
    }
    
    void mp_irqdomain_free(struct irq_domain *domain, unsigned int virq,
    		       unsigned int nr_irqs)
    {
    	struct irq_data *irq_data;
    	struct mp_chip_data *data;
    
    	BUG_ON(nr_irqs != 1);
    	irq_data = irq_domain_get_irq_data(domain, virq);
    	if (irq_data && irq_data->chip_data) {
    		data = irq_data->chip_data;
    		__remove_pin_from_irq(data, mp_irqdomain_ioapic_idx(domain),
    				      (int)irq_data->hwirq);
    		WARN_ON(!list_empty(&data->irq_2_pin));
    		kfree(irq_data->chip_data);
    	}
    	irq_domain_free_irqs_top(domain, virq, nr_irqs);
    }
    
    void mp_irqdomain_activate(struct irq_domain *domain,
    			   struct irq_data *irq_data)
    {
    	unsigned long flags;
    	struct irq_pin_list *entry;
    	struct mp_chip_data *data = irq_data->chip_data;
    
    	raw_spin_lock_irqsave(&ioapic_lock, flags);
    	for_each_irq_pin(entry, data->irq_2_pin)
    		__ioapic_write_entry(entry->apic, entry->pin, data->entry);
    	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
    }
    
    void mp_irqdomain_deactivate(struct irq_domain *domain,
    			     struct irq_data *irq_data)
    {
    	/* It won't be called for IRQ with multiple IOAPIC pins associated */
    	ioapic_mask_entry(mp_irqdomain_ioapic_idx(domain),
    			  (int)irq_data->hwirq);
    }
    
    int mp_irqdomain_ioapic_idx(struct irq_domain *domain)
    {
    	return (int)(long)domain->host_data;
    }
    
    const struct irq_domain_ops mp_ioapic_irqdomain_ops = {
    	.alloc		= mp_irqdomain_alloc,
    	.free		= mp_irqdomain_free,
    	.activate	= mp_irqdomain_activate,
    	.deactivate	= mp_irqdomain_deactivate,
    };