io_apic.c

/*
 *	Intel IO-APIC support for multi-Pentium hosts.
 *
 *	Copyright (C) 1997, 1998, 1999, 2000 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/smp_lock.h>
#include <linux/mc146818rtc.h>
#include <linux/compiler.h>
#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/pci.h>

#include <asm/io.h>
#include <asm/smp.h>
#include <asm/desc.h>
#include <asm/timer.h>
#include <asm/i8259.h>
#include <asm/nmi.h>
#include <asm/msidef.h>

#include <mach_apic.h>
#include <mach_apicdef.h>

#include "io_ports.h"

int (*ioapic_renumber_irq)(int ioapic, int irq);
atomic_t irq_mis_count;

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

static DEFINE_SPINLOCK(ioapic_lock);
static DEFINE_SPINLOCK(vector_lock);

int timer_over_8254 __initdata = 1;

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

/*
 * # of IRQ routing registers
 */
int nr_ioapic_registers[MAX_IO_APICS];

static int disable_timer_pin_1 __initdata;

/*
 * Rough estimation of how many shared IRQs there are, can
 * be changed anytime.
 */
#define MAX_PLUS_SHARED_IRQS NR_IRQS
#define PIN_MAP_SIZE (MAX_PLUS_SHARED_IRQS + NR_IRQS)

/*
 * This is performance-critical, we want to do it O(1)
 *
 * the indexing order of this array favors 1:1 mappings
 * between pins and IRQs.
 */

static struct irq_pin_list {
	int apic, pin, next;
} irq_2_pin[PIN_MAP_SIZE];

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;
	unsigned long flags;
	spin_lock_irqsave(&ioapic_lock, flags);
	eu.w1 = io_apic_read(apic, 0x10 + 2 * pin);
	eu.w2 = io_apic_read(apic, 0x11 + 2 * pin);
	spin_unlock_irqrestore(&ioapic_lock, flags);
	return eu.entry;
}

static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
{
	unsigned long flags;
	union entry_union eu;
	eu.entry = e;
	spin_lock_irqsave(&ioapic_lock, flags);
	io_apic_write(apic, 0x10 + 2*pin, eu.w1);
	io_apic_write(apic, 0x11 + 2*pin, eu.w2);
	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 void add_pin_to_irq(unsigned int irq, int apic, int pin)
{
	static int first_free_entry = NR_IRQS;
	struct irq_pin_list *entry = irq_2_pin + irq;

	while (entry->next)
		entry = irq_2_pin + entry->next;

	if (entry->pin != -1) {
		entry->next = first_free_entry;
		entry = irq_2_pin + entry->next;
		if (++first_free_entry >= PIN_MAP_SIZE)
			panic("io_apic.c: whoops");
	}
	entry->apic = apic;
	entry->pin = pin;
}

/*
 * Reroute an IRQ to a different pin.
 */
static void __init replace_pin_at_irq(unsigned int irq,
				      int oldapic, int oldpin,
				      int newapic, int newpin)
{
	struct irq_pin_list *entry = irq_2_pin + irq;

	while (1) {
		if (entry->apic == oldapic && entry->pin == oldpin) {
			entry->apic = newapic;
			entry->pin = newpin;
		}
		if (!entry->next)
			break;
		entry = irq_2_pin + entry->next;
	}
}

static void __modify_IO_APIC_irq (unsigned int irq, unsigned long enable, unsigned long disable)
{
	struct irq_pin_list *entry = irq_2_pin + irq;
	unsigned int pin, reg;

	for (;;) {
		pin = entry->pin;
		if (pin == -1)
			break;
		reg = io_apic_read(entry->apic, 0x10 + pin*2);
		reg &= ~disable;
		reg |= enable;
		io_apic_modify(entry->apic, 0x10 + pin*2, reg);
		if (!entry->next)
			break;
		entry = irq_2_pin + entry->next;
	}
}

/* mask = 1 */
static void __mask_IO_APIC_irq (unsigned int irq)
{
	__modify_IO_APIC_irq(irq, 0x00010000, 0);
}

/* mask = 0 */
static void __unmask_IO_APIC_irq (unsigned int irq)
{
	__modify_IO_APIC_irq(irq, 0, 0x00010000);
}

/* mask = 1, trigger = 0 */
static void __mask_and_edge_IO_APIC_irq (unsigned int irq)
{
	__modify_IO_APIC_irq(irq, 0x00010000, 0x00008000);
}

/* mask = 0, trigger = 1 */
static void __unmask_and_level_IO_APIC_irq (unsigned int irq)
{
	__modify_IO_APIC_irq(irq, 0x00008000, 0x00010000);
}

static void mask_IO_APIC_irq (unsigned int irq)
{
	unsigned long flags;

	spin_lock_irqsave(&ioapic_lock, flags);
	__mask_IO_APIC_irq(irq);
	spin_unlock_irqrestore(&ioapic_lock, flags);
}

static void unmask_IO_APIC_irq (unsigned int irq)
{
	unsigned long flags;

	spin_lock_irqsave(&ioapic_lock, flags);
	__unmask_IO_APIC_irq(irq);
	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;

	/*
	 * Disable it in the IO-APIC irq-routing table:
	 */
	memset(&entry, 0, sizeof(entry));
	entry.mask = 1;
	ioapic_write_entry(apic, pin, entry);
}

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

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

#ifdef CONFIG_SMP
static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t cpumask)
{
	unsigned long flags;
	int pin;
	struct irq_pin_list *entry = irq_2_pin + irq;
	unsigned int apicid_value;
	cpumask_t tmp;
	
	cpus_and(tmp, cpumask, cpu_online_map);
	if (cpus_empty(tmp))
		tmp = TARGET_CPUS;

	cpus_and(cpumask, tmp, CPU_MASK_ALL);

	apicid_value = cpu_mask_to_apicid(cpumask);
	/* Prepare to do the io_apic_write */
	apicid_value = apicid_value << 24;
	spin_lock_irqsave(&ioapic_lock, flags);
	for (;;) {
		pin = entry->pin;
		if (pin == -1)
			break;
		io_apic_write(entry->apic, 0x10 + 1 + pin*2, apicid_value);
		if (!entry->next)
			break;
		entry = irq_2_pin + entry->next;
	}
	set_native_irq_info(irq, cpumask);
	spin_unlock_irqrestore(&ioapic_lock, flags);
}

#if defined(CONFIG_IRQBALANCE)
# include <asm/processor.h>	/* kernel_thread() */
# include <linux/kernel_stat.h>	/* kstat */
# include <linux/slab.h>		/* kmalloc() */
# include <linux/timer.h>	/* time_after() */
 
#ifdef CONFIG_BALANCED_IRQ_DEBUG
#  define TDprintk(x...) do { printk("<%ld:%s:%d>: ", jiffies, __FILE__, __LINE__); printk(x); } while (0)
#  define Dprintk(x...) do { TDprintk(x); } while (0)
# else
#  define TDprintk(x...) 
#  define Dprintk(x...) 
# endif

#define IRQBALANCE_CHECK_ARCH -999
#define MAX_BALANCED_IRQ_INTERVAL	(5*HZ)
#define MIN_BALANCED_IRQ_INTERVAL	(HZ/2)
#define BALANCED_IRQ_MORE_DELTA		(HZ/10)
#define BALANCED_IRQ_LESS_DELTA		(HZ)

static int irqbalance_disabled __read_mostly = IRQBALANCE_CHECK_ARCH;
static int physical_balance __read_mostly;
static long balanced_irq_interval __read_mostly = MAX_BALANCED_IRQ_INTERVAL;

static struct irq_cpu_info {
	unsigned long * last_irq;
	unsigned long * irq_delta;
	unsigned long irq;
} irq_cpu_data[NR_CPUS];

#define CPU_IRQ(cpu)		(irq_cpu_data[cpu].irq)
#define LAST_CPU_IRQ(cpu,irq)   (irq_cpu_data[cpu].last_irq[irq])
#define IRQ_DELTA(cpu,irq) 	(irq_cpu_data[cpu].irq_delta[irq])

#define IDLE_ENOUGH(cpu,now) \
	(idle_cpu(cpu) && ((now) - per_cpu(irq_stat, (cpu)).idle_timestamp > 1))

#define IRQ_ALLOWED(cpu, allowed_mask)	cpu_isset(cpu, allowed_mask)

#define CPU_TO_PACKAGEINDEX(i) (first_cpu(cpu_sibling_map[i]))

static cpumask_t balance_irq_affinity[NR_IRQS] = {
	[0 ... NR_IRQS-1] = CPU_MASK_ALL
};

void set_balance_irq_affinity(unsigned int irq, cpumask_t mask)
{
	balance_irq_affinity[irq] = mask;
}

static unsigned long move(int curr_cpu, cpumask_t allowed_mask,
			unsigned long now, int direction)
{
	int search_idle = 1;
	int cpu = curr_cpu;

	goto inside;

	do {
		if (unlikely(cpu == curr_cpu))
			search_idle = 0;
inside:
		if (direction == 1) {
			cpu++;
			if (cpu >= NR_CPUS)
				cpu = 0;
		} else {
			cpu--;
			if (cpu == -1)
				cpu = NR_CPUS-1;
		}
	} while (!cpu_online(cpu) || !IRQ_ALLOWED(cpu,allowed_mask) ||
			(search_idle && !IDLE_ENOUGH(cpu,now)));

	return cpu;
}

static inline void balance_irq(int cpu, int irq)
{
	unsigned long now = jiffies;
	cpumask_t allowed_mask;
	unsigned int new_cpu;
		
	if (irqbalance_disabled)
		return; 

	cpus_and(allowed_mask, cpu_online_map, balance_irq_affinity[irq]);
	new_cpu = move(cpu, allowed_mask, now, 1);
	if (cpu != new_cpu) {
		set_pending_irq(irq, cpumask_of_cpu(new_cpu));
	}
}

static inline void rotate_irqs_among_cpus(unsigned long useful_load_threshold)
{
	int i, j;
	Dprintk("Rotating IRQs among CPUs.\n");
	for_each_online_cpu(i) {
		for (j = 0; j < NR_IRQS; j++) {
			if (!irq_desc[j].action)
				continue;
			/* Is it a significant load ?  */
			if (IRQ_DELTA(CPU_TO_PACKAGEINDEX(i),j) <
						useful_load_threshold)
				continue;
			balance_irq(i, j);
		}
	}
	balanced_irq_interval = max((long)MIN_BALANCED_IRQ_INTERVAL,
		balanced_irq_interval - BALANCED_IRQ_LESS_DELTA);	
	return;
}

static void do_irq_balance(void)
{
	int i, j;
	unsigned long max_cpu_irq = 0, min_cpu_irq = (~0);
	unsigned long move_this_load = 0;
	int max_loaded = 0, min_loaded = 0;
	int load;
	unsigned long useful_load_threshold = balanced_irq_interval + 10;
	int selected_irq;
	int tmp_loaded, first_attempt = 1;
	unsigned long tmp_cpu_irq;
	unsigned long imbalance = 0;
	cpumask_t allowed_mask, target_cpu_mask, tmp;

	for_each_possible_cpu(i) {
		int package_index;
		CPU_IRQ(i) = 0;
		if (!cpu_online(i))
			continue;
		package_index = CPU_TO_PACKAGEINDEX(i);
		for (j = 0; j < NR_IRQS; j++) {
			unsigned long value_now, delta;
			/* Is this an active IRQ? */
			if (!irq_desc[j].action)
				continue;
			if ( package_index == i )
				IRQ_DELTA(package_index,j) = 0;
			/* Determine the total count per processor per IRQ */
			value_now = (unsigned long) kstat_cpu(i).irqs[j];

			/* Determine the activity per processor per IRQ */
			delta = value_now - LAST_CPU_IRQ(i,j);

			/* Update last_cpu_irq[][] for the next time */
			LAST_CPU_IRQ(i,j) = value_now;

			/* Ignore IRQs whose rate is less than the clock */
			if (delta < useful_load_threshold)
				continue;
			/* update the load for the processor or package total */
			IRQ_DELTA(package_index,j) += delta;

			/* Keep track of the higher numbered sibling as well */
			if (i != package_index)
				CPU_IRQ(i) += delta;
			/*
			 * We have sibling A and sibling B in the package
			 *
			 * cpu_irq[A] = load for cpu A + load for cpu B
			 * cpu_irq[B] = load for cpu B
			 */
			CPU_IRQ(package_index) += delta;
		}
	}
	/* Find the least loaded processor package */
	for_each_online_cpu(i) {
		if (i != CPU_TO_PACKAGEINDEX(i))
			continue;
		if (min_cpu_irq > CPU_IRQ(i)) {
			min_cpu_irq = CPU_IRQ(i);
			min_loaded = i;
		}
	}
	max_cpu_irq = ULONG_MAX;

tryanothercpu:
	/* Look for heaviest loaded processor.
	 * We may come back to get the next heaviest loaded processor.
	 * Skip processors with trivial loads.
	 */
	tmp_cpu_irq = 0;
	tmp_loaded = -1;
	for_each_online_cpu(i) {
		if (i != CPU_TO_PACKAGEINDEX(i))
			continue;
		if (max_cpu_irq <= CPU_IRQ(i)) 
			continue;
		if (tmp_cpu_irq < CPU_IRQ(i)) {
			tmp_cpu_irq = CPU_IRQ(i);
			tmp_loaded = i;
		}
	}

	if (tmp_loaded == -1) {
 	 /* In the case of small number of heavy interrupt sources, 
	  * loading some of the cpus too much. We use Ingo's original 
	  * approach to rotate them around.
	  */
		if (!first_attempt && imbalance >= useful_load_threshold) {
			rotate_irqs_among_cpus(useful_load_threshold);
			return;
		}
		goto not_worth_the_effort;
	}
	
	first_attempt = 0;		/* heaviest search */
	max_cpu_irq = tmp_cpu_irq;	/* load */
	max_loaded = tmp_loaded;	/* processor */
	imbalance = (max_cpu_irq - min_cpu_irq) / 2;
	
	Dprintk("max_loaded cpu = %d\n", max_loaded);
	Dprintk("min_loaded cpu = %d\n", min_loaded);
	Dprintk("max_cpu_irq load = %ld\n", max_cpu_irq);
	Dprintk("min_cpu_irq load = %ld\n", min_cpu_irq);
	Dprintk("load imbalance = %lu\n", imbalance);

	/* if imbalance is less than approx 10% of max load, then
	 * observe diminishing returns action. - quit
	 */
	if (imbalance < (max_cpu_irq >> 3)) {
		Dprintk("Imbalance too trivial\n");
		goto not_worth_the_effort;
	}

tryanotherirq:
	/* if we select an IRQ to move that can't go where we want, then
	 * see if there is another one to try.
	 */
	move_this_load = 0;
	selected_irq = -1;
	for (j = 0; j < NR_IRQS; j++) {
		/* Is this an active IRQ? */
		if (!irq_desc[j].action)
			continue;
		if (imbalance <= IRQ_DELTA(max_loaded,j))
			continue;
		/* Try to find the IRQ that is closest to the imbalance
		 * without going over.
		 */
		if (move_this_load < IRQ_DELTA(max_loaded,j)) {
			move_this_load = IRQ_DELTA(max_loaded,j);
			selected_irq = j;
		}
	}
	if (selected_irq == -1) {
		goto tryanothercpu;
	}

	imbalance = move_this_load;
	
	/* For physical_balance case, we accumlated both load
	 * values in the one of the siblings cpu_irq[],
	 * to use the same code for physical and logical processors
	 * as much as possible. 
	 *
	 * NOTE: the cpu_irq[] array holds the sum of the load for
	 * sibling A and sibling B in the slot for the lowest numbered
	 * sibling (A), _AND_ the load for sibling B in the slot for
	 * the higher numbered sibling.
	 *
	 * We seek the least loaded sibling by making the comparison
	 * (A+B)/2 vs B
	 */
	load = CPU_IRQ(min_loaded) >> 1;
	for_each_cpu_mask(j, cpu_sibling_map[min_loaded]) {
		if (load > CPU_IRQ(j)) {
			/* This won't change cpu_sibling_map[min_loaded] */
			load = CPU_IRQ(j);
			min_loaded = j;
		}
	}

	cpus_and(allowed_mask,
		cpu_online_map,
		balance_irq_affinity[selected_irq]);
	target_cpu_mask = cpumask_of_cpu(min_loaded);
	cpus_and(tmp, target_cpu_mask, allowed_mask);

	if (!cpus_empty(tmp)) {

		Dprintk("irq = %d moved to cpu = %d\n",
				selected_irq, min_loaded);
		/* mark for change destination */
		set_pending_irq(selected_irq, cpumask_of_cpu(min_loaded));

		/* Since we made a change, come back sooner to 
		 * check for more variation.
		 */
		balanced_irq_interval = max((long)MIN_BALANCED_IRQ_INTERVAL,
			balanced_irq_interval - BALANCED_IRQ_LESS_DELTA);	
		return;
	}
	goto tryanotherirq;

not_worth_the_effort:
	/*
	 * if we did not find an IRQ to move, then adjust the time interval
	 * upward
	 */
	balanced_irq_interval = min((long)MAX_BALANCED_IRQ_INTERVAL,
		balanced_irq_interval + BALANCED_IRQ_MORE_DELTA);	
	Dprintk("IRQ worth rotating not found\n");
	return;
}

static int balanced_irq(void *unused)
{
	int i;
	unsigned long prev_balance_time = jiffies;
	long time_remaining = balanced_irq_interval;

	daemonize("kirqd");
	
	/* push everything to CPU 0 to give us a starting point.  */
	for (i = 0 ; i < NR_IRQS ; i++) {
		irq_desc[i].pending_mask = cpumask_of_cpu(0);
		set_pending_irq(i, cpumask_of_cpu(0));
	}

	for ( ; ; ) {
		time_remaining = schedule_timeout_interruptible(time_remaining);
		try_to_freeze();
		if (time_after(jiffies,
				prev_balance_time+balanced_irq_interval)) {
			preempt_disable();
			do_irq_balance();
			prev_balance_time = jiffies;
			time_remaining = balanced_irq_interval;
			preempt_enable();
		}
	}
	return 0;
}

static int __init balanced_irq_init(void)
{
	int i;
	struct cpuinfo_x86 *c;
	cpumask_t tmp;

	cpus_shift_right(tmp, cpu_online_map, 2);
        c = &boot_cpu_data;
	/* When not overwritten by the command line ask subarchitecture. */
	if (irqbalance_disabled == IRQBALANCE_CHECK_ARCH)
		irqbalance_disabled = NO_BALANCE_IRQ;
	if (irqbalance_disabled)
		return 0;
	
	 /* disable irqbalance completely if there is only one processor online */
	if (num_online_cpus() < 2) {
		irqbalance_disabled = 1;
		return 0;
	}
	/*
	 * Enable physical balance only if more than 1 physical processor
	 * is present
	 */
	if (smp_num_siblings > 1 && !cpus_empty(tmp))
		physical_balance = 1;

	for_each_online_cpu(i) {
		irq_cpu_data[i].irq_delta = kmalloc(sizeof(unsigned long) * NR_IRQS, GFP_KERNEL);
		irq_cpu_data[i].last_irq = kmalloc(sizeof(unsigned long) * NR_IRQS, GFP_KERNEL);
		if (irq_cpu_data[i].irq_delta == NULL || irq_cpu_data[i].last_irq == NULL) {
			printk(KERN_ERR "balanced_irq_init: out of memory");
			goto failed;
		}
		memset(irq_cpu_data[i].irq_delta,0,sizeof(unsigned long) * NR_IRQS);
		memset(irq_cpu_data[i].last_irq,0,sizeof(unsigned long) * NR_IRQS);
	}
	
	printk(KERN_INFO "Starting balanced_irq\n");
	if (kernel_thread(balanced_irq, NULL, CLONE_KERNEL) >= 0) 
		return 0;
	else 
		printk(KERN_ERR "balanced_irq_init: failed to spawn balanced_irq");
failed:
	for_each_possible_cpu(i) {
		kfree(irq_cpu_data[i].irq_delta);
		irq_cpu_data[i].irq_delta = NULL;
		kfree(irq_cpu_data[i].last_irq);
		irq_cpu_data[i].last_irq = NULL;
	}
	return 0;
}

int __init irqbalance_disable(char *str)
{
	irqbalance_disabled = 1;
	return 1;
}

__setup("noirqbalance", irqbalance_disable);

late_initcall(balanced_irq_init);
#endif /* CONFIG_IRQBALANCE */
#endif /* CONFIG_SMP */

#ifndef CONFIG_SMP
void fastcall send_IPI_self(int vector)
{
	unsigned int cfg;

	/*
	 * Wait for idle.
	 */
	apic_wait_icr_idle();
	cfg = APIC_DM_FIXED | APIC_DEST_SELF | vector | APIC_DEST_LOGICAL;
	/*
	 * Send the IPI. The write to APIC_ICR fires this off.
	 */
	apic_write_around(APIC_ICR, cfg);
}
#endif /* !CONFIG_SMP */


/*
 * 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];
static int pirqs_enabled;
int skip_ioapic_setup;

static int __init ioapic_setup(char *str)
{
	skip_ioapic_setup = 1;
	return 1;
}

__setup("noapic", ioapic_setup);

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

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

	for (i = 0; i < MAX_PIRQS; i++)
		pirq_entries[i] = -1;

	pirqs_enabled = 1;
	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);

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

	for (i = 0; i < mp_irq_entries; i++)
		if (mp_irqs[i].mpc_irqtype == type &&
		    (mp_irqs[i].mpc_dstapic == mp_ioapics[apic].mpc_apicid ||
		     mp_irqs[i].mpc_dstapic == MP_APIC_ALL) &&
		    mp_irqs[i].mpc_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].mpc_srcbus;

		if ((mp_bus_id_to_type[lbus] == MP_BUS_ISA ||
		     mp_bus_id_to_type[lbus] == MP_BUS_EISA ||
		     mp_bus_id_to_type[lbus] == MP_BUS_MCA ||
		     mp_bus_id_to_type[lbus] == MP_BUS_NEC98
		    ) &&
		    (mp_irqs[i].mpc_irqtype == type) &&
		    (mp_irqs[i].mpc_srcbusirq == irq))

			return mp_irqs[i].mpc_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].mpc_srcbus;

		if ((mp_bus_id_to_type[lbus] == MP_BUS_ISA ||
		     mp_bus_id_to_type[lbus] == MP_BUS_EISA ||
		     mp_bus_id_to_type[lbus] == MP_BUS_MCA ||
		     mp_bus_id_to_type[lbus] == MP_BUS_NEC98
		    ) &&
		    (mp_irqs[i].mpc_irqtype == type) &&
		    (mp_irqs[i].mpc_srcbusirq == irq))
			break;
	}
	if (i < mp_irq_entries) {
		int apic;
		for(apic = 0; apic < nr_ioapics; apic++) {
			if (mp_ioapics[apic].mpc_apicid == mp_irqs[i].mpc_dstapic)
				return apic;
		}
	}

	return -1;
}

/*
 * Find a specific PCI IRQ entry.
 * Not an __init, possibly needed by modules
 */
static int pin_2_irq(int idx, int apic, int pin);

int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin)
{
	int apic, i, best_guess = -1;

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

		for (apic = 0; apic < nr_ioapics; apic++)
			if (mp_ioapics[apic].mpc_apicid == mp_irqs[i].mpc_dstapic ||
			    mp_irqs[i].mpc_dstapic == MP_APIC_ALL)
				break;

		if ((mp_bus_id_to_type[lbus] == MP_BUS_PCI) &&
		    !mp_irqs[i].mpc_irqtype &&
		    (bus == lbus) &&
		    (slot == ((mp_irqs[i].mpc_srcbusirq >> 2) & 0x1f))) {
			int irq = pin_2_irq(i,apic,mp_irqs[i].mpc_dstirq);

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

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

/*
 * 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 TARGET_CPUS
 */
#ifdef CONFIG_SMP
void __init setup_ioapic_dest(void)
{
	int pin, ioapic, irq, irq_entry;

	if (skip_ioapic_setup == 1)
		return;

	for (ioapic = 0; ioapic < nr_ioapics; ioapic++) {
		for (pin = 0; pin < nr_ioapic_registers[ioapic]; pin++) {
			irq_entry = find_irq_entry(ioapic, pin, mp_INT);
			if (irq_entry == -1)
				continue;
			irq = pin_2_irq(irq_entry, ioapic, pin);
			set_ioapic_affinity_irq(irq, TARGET_CPUS);
		}

	}
}
#endif

/*
 * EISA Edge/Level control register, ELCR
 */
static int EISA_ELCR(unsigned int irq)
{
	if (irq < 16) {
		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;
}

/* 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].mpc_srcbusirq))
#define default_EISA_polarity(idx)	(0)

/* 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)

/* 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)

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

#define default_MCA_trigger(idx)	(1)
#define default_MCA_polarity(idx)	(0)

/* NEC98 interrupts are always polarity zero edge triggered,
 * when listed as conforming in the MP table. */

#define default_NEC98_trigger(idx)     (0)
#define default_NEC98_polarity(idx)    (0)

static int __init MPBIOS_polarity(int idx)
{
	int bus = mp_irqs[idx].mpc_srcbus;
	int polarity;

	/*
	 * Determine IRQ line polarity (high active or low active):
	 */
	switch (mp_irqs[idx].mpc_irqflag & 3)
	{
		case 0: /* conforms, ie. bus-type dependent polarity */
		{
			switch (mp_bus_id_to_type[bus])
			{
				case MP_BUS_ISA: /* ISA pin */
				{
					polarity = default_ISA_polarity(idx);
					break;
				}
				case MP_BUS_EISA: /* EISA pin */
				{
					polarity = default_EISA_polarity(idx);
					break;
				}
				case MP_BUS_PCI: /* PCI pin */
				{
					polarity = default_PCI_polarity(idx);
					break;
				}
				case MP_BUS_MCA: /* MCA pin */
				{
					polarity = default_MCA_polarity(idx);
					break;
				}
				case MP_BUS_NEC98: /* NEC 98 pin */
				{
					polarity = default_NEC98_polarity(idx);
					break;
				}
				default:
				{
					printk(KERN_WARNING "broken BIOS!!\n");
					polarity = 1;
					break;
				}
			}
			break;
		}
		case 1: /* high active */
		{
			polarity = 0;
			break;
		}
		case 2: /* reserved */
		{
			printk(KERN_WARNING "broken BIOS!!\n");
			polarity = 1;
			break;
		}
		case 3: /* low active */
		{
			polarity = 1;
			break;
		}
		default: /* invalid */
		{
			printk(KERN_WARNING "broken BIOS!!\n");
			polarity = 1;