path: root/xen/arch/ia64/irq.c

/*
 *	linux/arch/ia64/kernel/irq.c
 *
 *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 *
 * Copyright (C) Ashok Raj<ashok.raj@intel.com>, Intel Corporation 2004
 *
 * 4/14/2004: Added code to handle cpu migration and do safe irq
 *			migration without lossing interrupts for iosapic
 *			architecture.
 */

/*
 * (mostly architecture independent, will move to kernel/irq.c in 2.5.)
 *
 * IRQs are in fact implemented a bit like signal handlers for the kernel.
 * Naturally it's not a 1:1 relation, but there are similarities.
 */

#include <linux/config.h>
#include <linux/errno.h>
#include <linux/module.h>
#ifndef XEN
#include <linux/signal.h>
#endif
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/slab.h>
#ifndef XEN
#include <linux/random.h>
#include <linux/cpu.h>
#endif
#include <linux/ctype.h>
#ifndef XEN
#include <linux/smp_lock.h>
#endif
#include <linux/init.h>
#ifndef XEN
#include <linux/kernel_stat.h>
#endif
#include <linux/irq.h>
#ifndef XEN
#include <linux/proc_fs.h>
#endif
#include <linux/seq_file.h>
#ifndef XEN
#include <linux/kallsyms.h>
#include <linux/notifier.h>
#endif

#include <asm/atomic.h>
#ifndef XEN
#include <asm/cpu.h>
#endif
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#ifndef XEN
#include <asm/tlbflush.h>
#endif
#include <asm/delay.h>
#include <asm/irq.h>

#ifdef XEN
#include <xen/event.h>
#define _irq_desc irq_desc
#define irq_descp(irq) &irq_desc[irq]
#define apicid_to_phys_cpu_present(x)	1
#endif


/*
 * Linux has a controller-independent x86 interrupt architecture.
 * every controller has a 'controller-template', that is used
 * by the main code to do the right thing. Each driver-visible
 * interrupt source is transparently wired to the appropriate
 * controller. Thus drivers need not be aware of the
 * interrupt-controller.
 *
 * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
 * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
 * (IO-APICs assumed to be messaging to Pentium local-APICs)
 *
 * the code is designed to be easily extended with new/different
 * interrupt controllers, without having to do assembly magic.
 */

/*
 * Controller mappings for all interrupt sources:
 */
irq_desc_t _irq_desc[NR_IRQS] __cacheline_aligned = {
	[0 ... NR_IRQS-1] = {
		.status = IRQ_DISABLED,
		.handler = &no_irq_type,
		.lock = SPIN_LOCK_UNLOCKED
	}
};

/*
 * This is updated when the user sets irq affinity via /proc
 */
cpumask_t    __cacheline_aligned pending_irq_cpumask[NR_IRQS];

#ifdef CONFIG_IA64_GENERIC
irq_desc_t * __ia64_irq_desc (unsigned int irq)
{
	return _irq_desc + irq;
}

ia64_vector __ia64_irq_to_vector (unsigned int irq)
{
	return (ia64_vector) irq;
}

unsigned int __ia64_local_vector_to_irq (ia64_vector vec)
{
	return (unsigned int) vec;
}
#endif

static void register_irq_proc (unsigned int irq);

/*
 * Special irq handlers.
 */

#ifdef XEN
void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }
#else
irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
{ return IRQ_NONE; }
#endif

/*
 * Generic no controller code
 */

static void enable_none(unsigned int irq) { }
static unsigned int startup_none(unsigned int irq) { return 0; }
static void disable_none(unsigned int irq) { }
static void ack_none(unsigned int irq)
{
/*
 * 'what should we do if we get a hw irq event on an illegal vector'.
 * each architecture has to answer this themselves, it doesn't deserve
 * a generic callback i think.
 */
#ifdef CONFIG_X86
	printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
#ifdef CONFIG_X86_LOCAL_APIC
	/*
	 * Currently unexpected vectors happen only on SMP and APIC.
	 * We _must_ ack these because every local APIC has only N
	 * irq slots per priority level, and a 'hanging, unacked' IRQ
	 * holds up an irq slot - in excessive cases (when multiple
	 * unexpected vectors occur) that might lock up the APIC
	 * completely.
	 */
	ack_APIC_irq();
#endif
#endif
#ifdef CONFIG_IA64
	printk(KERN_ERR "Unexpected irq vector 0x%x on CPU %u!\n", irq, smp_processor_id());
#endif
}

/* startup is the same as "enable", shutdown is same as "disable" */
#define shutdown_none	disable_none
#define end_none	enable_none

struct hw_interrupt_type no_irq_type = {
	"none",
	startup_none,
	shutdown_none,
	enable_none,
	disable_none,
	ack_none,
	end_none
};

atomic_t irq_err_count;
#ifdef CONFIG_X86_IO_APIC
#ifdef APIC_MISMATCH_DEBUG
atomic_t irq_mis_count;
#endif
#endif

/*
 * Generic, controller-independent functions:
 */

#ifndef XEN
int show_interrupts(struct seq_file *p, void *v)
{
	int j, i = *(loff_t *) v;
	struct irqaction * action;
	irq_desc_t *idesc;
	unsigned long flags;

	if (i == 0) {
		seq_puts(p, "           ");
		for (j=0; j<NR_CPUS; j++)
			if (cpu_online(j))
				seq_printf(p, "CPU%d       ",j);
		seq_putc(p, '\n');
	}

	if (i < NR_IRQS) {
		idesc = irq_descp(i);
		spin_lock_irqsave(&idesc->lock, flags);
		action = idesc->action;
		if (!action)
			goto skip;
		seq_printf(p, "%3d: ",i);
#ifndef CONFIG_SMP
		seq_printf(p, "%10u ", kstat_irqs(i));
#else
		for (j = 0; j < NR_CPUS; j++)
			if (cpu_online(j))
				seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
#endif
		seq_printf(p, " %14s", idesc->handler->typename);
		seq_printf(p, "  %s", action->name);

		for (action=action->next; action; action = action->next)
			seq_printf(p, ", %s", action->name);

		seq_putc(p, '\n');
skip:
		spin_unlock_irqrestore(&idesc->lock, flags);
	} else if (i == NR_IRQS) {
		seq_puts(p, "NMI: ");
		for (j = 0; j < NR_CPUS; j++)
			if (cpu_online(j))
				seq_printf(p, "%10u ", nmi_count(j));
		seq_putc(p, '\n');
#ifdef CONFIG_X86_LOCAL_APIC
		seq_puts(p, "LOC: ");
		for (j = 0; j < NR_CPUS; j++)
			if (cpu_online(j))
				seq_printf(p, "%10u ", irq_stat[j].apic_timer_irqs);
		seq_putc(p, '\n');
#endif
		seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
#ifdef CONFIG_X86_IO_APIC
#ifdef APIC_MISMATCH_DEBUG
		seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
#endif
#endif
	}
	return 0;
}
#endif

#ifdef CONFIG_SMP
inline void synchronize_irq(unsigned int irq)
{
	while (irq_descp(irq)->status & IRQ_INPROGRESS)
		cpu_relax();
}
EXPORT_SYMBOL(synchronize_irq);
#endif

/*
 * This should really return information about whether
 * we should do bottom half handling etc. Right now we
 * end up _always_ checking the bottom half, which is a
 * waste of time and is not what some drivers would
 * prefer.
 */
int handle_IRQ_event(unsigned int irq,
		struct pt_regs *regs, struct irqaction *action)
{
	int status = 1;	/* Force the "do bottom halves" bit */
	int retval = 0;

#ifndef XEN
	if (!(action->flags & SA_INTERRUPT))
#endif
		local_irq_enable();

#ifdef XEN
		action->handler(irq, action->dev_id, regs);
#else
	do {
		status |= action->flags;
		retval |= action->handler(irq, action->dev_id, regs);
		action = action->next;
	} while (action);
	if (status & SA_SAMPLE_RANDOM)
		add_interrupt_randomness(irq);
#endif
	local_irq_disable();
	return retval;
}

#ifndef XEN
static void __report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
{
	struct irqaction *action;

	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
		printk(KERN_ERR "irq event %d: bogus return value %x\n",
				irq, action_ret);
	} else {
		printk(KERN_ERR "irq %d: nobody cared!\n", irq);
	}
	dump_stack();
	printk(KERN_ERR "handlers:\n");
	action = desc->action;
	do {
		printk(KERN_ERR "[<%p>]", action->handler);
		print_symbol(" (%s)",
			(unsigned long)action->handler);
		printk("\n");
		action = action->next;
	} while (action);
}

static void report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
{
	static int count = 100;

	if (count) {
		count--;
		__report_bad_irq(irq, desc, action_ret);
	}
}
#endif

static int noirqdebug;

static int __init noirqdebug_setup(char *str)
{
	noirqdebug = 1;
	printk("IRQ lockup detection disabled\n");
	return 1;
}

__setup("noirqdebug", noirqdebug_setup);

/*
 * If 99,900 of the previous 100,000 interrupts have not been handled then
 * assume that the IRQ is stuck in some manner.  Drop a diagnostic and try to
 * turn the IRQ off.
 *
 * (The other 100-of-100,000 interrupts may have been a correctly-functioning
 *  device sharing an IRQ with the failing one)
 *
 * Called under desc->lock
 */
#ifndef XEN
static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
{
	if (action_ret != IRQ_HANDLED) {
		desc->irqs_unhandled++;
		if (action_ret != IRQ_NONE)
			report_bad_irq(irq, desc, action_ret);
	}

	desc->irq_count++;
	if (desc->irq_count < 100000)
		return;

	desc->irq_count = 0;
	if (desc->irqs_unhandled > 99900) {
		/*
		 * The interrupt is stuck
		 */
		__report_bad_irq(irq, desc, action_ret);
		/*
		 * Now kill the IRQ
		 */
		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
		desc->status |= IRQ_DISABLED;
		desc->handler->disable(irq);
	}
	desc->irqs_unhandled = 0;
}
#endif

/*
 * Generic enable/disable code: this just calls
 * down into the PIC-specific version for the actual
 * hardware disable after having gotten the irq
 * controller lock.
 */

/**
 *	disable_irq_nosync - disable an irq without waiting
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Disables and Enables are
 *	nested.
 *	Unlike disable_irq(), this function does not ensure existing
 *	instances of the IRQ handler have completed before returning.
 *
 *	This function may be called from IRQ context.
 */

inline void disable_irq_nosync(unsigned int irq)
{
	irq_desc_t *desc = irq_descp(irq);
	unsigned long flags;

	spin_lock_irqsave(&desc->lock, flags);
	if (!desc->depth++) {
		desc->status |= IRQ_DISABLED;
		desc->handler->disable(irq);
	}
	spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL(disable_irq_nosync);

/**
 *	disable_irq - disable an irq and wait for completion
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Enables and Disables are
 *	nested.
 *	This function waits for any pending IRQ handlers for this interrupt
 *	to complete before returning. If you use this function while
 *	holding a resource the IRQ handler may need you will deadlock.
 *
 *	This function may be called - with care - from IRQ context.
 */

void disable_irq(unsigned int irq)
{
	irq_desc_t *desc = irq_descp(irq);

	disable_irq_nosync(irq);
	if (desc->action)
		synchronize_irq(irq);
}
EXPORT_SYMBOL(disable_irq);

/**
 *	enable_irq - enable handling of an irq
 *	@irq: Interrupt to enable
 *
 *	Undoes the effect of one call to disable_irq().  If this
 *	matches the last disable, processing of interrupts on this
 *	IRQ line is re-enabled.
 *
 *	This function may be called from IRQ context.
 */

void enable_irq(unsigned int irq)
{
	irq_desc_t *desc = irq_descp(irq);
	unsigned long flags;

	spin_lock_irqsave(&desc->lock, flags);
	switch (desc->depth) {
	case 1: {
		unsigned int status = desc->status & ~IRQ_DISABLED;
		desc->status = status;
#ifndef XEN
		if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
			desc->status = status | IRQ_REPLAY;
			hw_resend_irq(desc->handler,irq);
		}
#endif
		desc->handler->enable(irq);
		/* fall-through */
	}
	default:
		desc->depth--;
		break;
	case 0:
		printk(KERN_ERR "enable_irq(%u) unbalanced from %p\n",
		       irq, (void *) __builtin_return_address(0));
	}
	spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL(enable_irq);

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */
fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
{
	irq_desc_t *desc = irq_desc + irq;
	struct irqaction * action;
	unsigned int status;

#ifndef XEN
	kstat_this_cpu.irqs[irq]++;
#endif
	if (desc->status & IRQ_PER_CPU) {
		irqreturn_t action_ret;

		/*
		 * No locking required for CPU-local interrupts:
		 */
		desc->handler->ack(irq);
		action_ret = handle_IRQ_event(irq, regs, desc->action);
#ifndef XEN
		if (!noirqdebug)
			note_interrupt(irq, desc, action_ret);
#endif
		desc->handler->end(irq);
		return 1;
	}

	spin_lock(&desc->lock);
	desc->handler->ack(irq);
	/*
	 * REPLAY is when Linux resends an IRQ that was dropped earlier
	 * WAITING is used by probe to mark irqs that are being tested
	 */
#ifdef XEN
	status = desc->status & ~IRQ_REPLAY;
#else
	status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
#endif
	status |= IRQ_PENDING; /* we _want_ to handle it */

	/*
	 * If the IRQ is disabled for whatever reason, we cannot
	 * use the action we have.
	 */
	action = NULL;
	if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
		action = desc->action;
		status &= ~IRQ_PENDING; /* we commit to handling */
		status |= IRQ_INPROGRESS; /* we are handling it */
	}
	desc->status = status;

	/*
	 * If there is no IRQ handler or it was disabled, exit early.
	 * Since we set PENDING, if another processor is handling
	 * a different instance of this same irq, the other processor
	 * will take care of it.
	 */
	if (unlikely(!action))
		goto out;

	/*
	 * Edge triggered interrupts need to remember
	 * pending events.
	 * This applies to any hw interrupts that allow a second
	 * instance of the same irq to arrive while we are in do_IRQ
	 * or in the handler. But the code here only handles the _second_
	 * instance of the irq, not the third or fourth. So it is mostly
	 * useful for irq hardware that does not mask cleanly in an
	 * SMP environment.
	 */
	for (;;) {
		irqreturn_t action_ret;

		spin_unlock(&desc->lock);

		action_ret = handle_IRQ_event(irq, regs, action);

		spin_lock(&desc->lock);
#ifndef XEN
		if (!noirqdebug)
			note_interrupt(irq, desc, action_ret);
#endif
		if (likely(!(desc->status & IRQ_PENDING)))
			break;
		desc->status &= ~IRQ_PENDING;
	}
	desc->status &= ~IRQ_INPROGRESS;

out:
	/*
	 * The ->end() handler has to deal with interrupts which got
	 * disabled while the handler was running.
	 */
	desc->handler->end(irq);
	spin_unlock(&desc->lock);

	return 1;
}

/**
 *	request_irq - allocate an interrupt line
 *	@irq: Interrupt line to allocate
 *	@handler: Function to be called when the IRQ occurs
 *	@irqflags: Interrupt type flags
 *	@devname: An ascii name for the claiming device
 *	@dev_id: A cookie passed back to the handler function
 *
 *	This call allocates interrupt resources and enables the
 *	interrupt line and IRQ handling. From the point this
 *	call is made your handler function may be invoked. Since
 *	your handler function must clear any interrupt the board 
 *	raises, you must take care both to initialise your hardware
 *	and to set up the interrupt handler in the right order.
 *
 *	Dev_id must be globally unique. Normally the address of the
 *	device data structure is used as the cookie. Since the handler
 *	receives this value it makes sense to use it.
 *
 *	If your interrupt is shared you must pass a non NULL dev_id
 *	as this is required when freeing the interrupt.
 *
 *	Flags:
 *
 *	SA_SHIRQ		Interrupt is shared
 *
 *	SA_INTERRUPT		Disable local interrupts while processing
 *
 *	SA_SAMPLE_RANDOM	The interrupt can be used for entropy
 *
 */

int request_irq(unsigned int irq,
		irqreturn_t (*handler)(int, void *, struct pt_regs *),
		unsigned long irqflags,
		const char * devname,
		void *dev_id)
{
	int retval;
	struct irqaction * action;

#if 1
	/*
	 * Sanity-check: shared interrupts should REALLY pass in
	 * a real dev-ID, otherwise we'll have trouble later trying
	 * to figure out which interrupt is which (messes up the
	 * interrupt freeing logic etc).
	 */
	if (irqflags & SA_SHIRQ) {
		if (!dev_id)
			printk(KERN_ERR "Bad boy: %s called us without a dev_id!\n", devname);
	}
#endif

	if (irq >= NR_IRQS)
		return -EINVAL;
	if (!handler)
		return -EINVAL;

	action = xmalloc(struct irqaction);
	if (!action)
		return -ENOMEM;

	action->handler = handler;
#ifndef XEN
	action->flags = irqflags;
	action->mask = 0;
#endif
	action->name = devname;
#ifndef XEN
	action->next = NULL;
#endif
	action->dev_id = dev_id;

	retval = setup_irq(irq, action);
	if (retval)
		xfree(action);
	return retval;
}

EXPORT_SYMBOL(request_irq);

/**
 *	free_irq - free an interrupt
 *	@irq: Interrupt line to free
 *	@dev_id: Device identity to free
 *
 *	Remove an interrupt handler. The handler is removed and if the
 *	interrupt line is no longer in use by any driver it is disabled.
 *	On a shared IRQ the caller must ensure the interrupt is disabled
 *	on the card it drives before calling this function. The function
 *	does not return until any executing interrupts for this IRQ
 *	have completed.
 *
 *	This function must not be called from interrupt context.
 */

#ifdef XEN
void free_irq(unsigned int irq)
#else
void free_irq(unsigned int irq, void *dev_id)
#endif
{
	irq_desc_t *desc;
	struct irqaction **p;
	unsigned long flags;

	if (irq >= NR_IRQS)
		return;

	desc = irq_descp(irq);
	spin_lock_irqsave(&desc->lock,flags);
#ifdef XEN
	if (desc->action) {
		struct irqaction * action = desc->action;
		desc->action = NULL;
#else
	p = &desc->action;
	for (;;) {
		struct irqaction * action = *p;
		if (action) {
			struct irqaction **pp = p;
			p = &action->next;
			if (action->dev_id != dev_id)
				continue;

			/* Found it - now remove it from the list of entries */
			*pp = action->next;
			if (!desc->action) {
#endif
				desc->status |= IRQ_DISABLED;
				desc->handler->shutdown(irq);
#ifndef XEN
			}
#endif
			spin_unlock_irqrestore(&desc->lock,flags);

			/* Wait to make sure it's not being used on another CPU */
			synchronize_irq(irq);
			xfree(action);
			return;
		}
		printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
		spin_unlock_irqrestore(&desc->lock,flags);
#ifndef XEN
		return;
	}
#endif
}

EXPORT_SYMBOL(free_irq);

/*
 * IRQ autodetection code..
 *
 * This depends on the fact that any interrupt that
 * comes in on to an unassigned handler will get stuck
 * with "IRQ_WAITING" cleared and the interrupt
 * disabled.
 */

static DECLARE_MUTEX(probe_sem);

/**
 *	probe_irq_on	- begin an interrupt autodetect
 *
 *	Commence probing for an interrupt. The interrupts are scanned
 *	and a mask of potential interrupt lines is returned.
 *
 */

#ifndef XEN
unsigned long probe_irq_on(void)
{
	unsigned int i;
	irq_desc_t *desc;
	unsigned long val;
	unsigned long delay;

	down(&probe_sem);
	/*
	 * something may have generated an irq long ago and we want to
	 * flush such a longstanding irq before considering it as spurious.
	 */
	for (i = NR_IRQS-1; i > 0; i--)  {
		desc = irq_descp(i);

		spin_lock_irq(&desc->lock);
		if (!desc->action)
			desc->handler->startup(i);
		spin_unlock_irq(&desc->lock);
	}

	/* Wait for longstanding interrupts to trigger. */
	for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
		/* about 20ms delay */ barrier();

	/*
	 * enable any unassigned irqs
	 * (we must startup again here because if a longstanding irq
	 * happened in the previous stage, it may have masked itself)
	 */
	for (i = NR_IRQS-1; i > 0; i--) {
		desc = irq_descp(i);

		spin_lock_irq(&desc->lock);
		if (!desc->action) {
			desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
			if (desc->handler->startup(i))
				desc->status |= IRQ_PENDING;
		}
		spin_unlock_irq(&desc->lock);
	}

	/*
	 * Wait for spurious interrupts to trigger
	 */
	for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
		/* about 100ms delay */ barrier();

	/*
	 * Now filter out any obviously spurious interrupts
	 */
	val = 0;
	for (i = 0; i < NR_IRQS; i++) {
		irq_desc_t *desc = irq_descp(i);
		unsigned int status;

		spin_lock_irq(&desc->lock);
		status = desc->status;

		if (status & IRQ_AUTODETECT) {
			/* It triggered already - consider it spurious. */
			if (!(status & IRQ_WAITING)) {
				desc->status = status & ~IRQ_AUTODETECT;
				desc->handler->shutdown(i);
			} else
				if (i < 32)
					val |= 1 << i;
		}
		spin_unlock_irq(&desc->lock);
	}

	return val;
}

EXPORT_SYMBOL(probe_irq_on);

/**
 *	probe_irq_mask - scan a bitmap of interrupt lines
 *	@val:	mask of interrupts to consider
 *
 *	Scan the ISA bus interrupt lines and return a bitmap of
 *	active interrupts. The interrupt probe logic state is then
 *	returned to its previous value.
 *
 *	Note: we need to scan all the irq's even though we will
 *	only return ISA irq numbers - just so that we reset them
 *	all to a known state.
 */
unsigned int probe_irq_mask(unsigned long val)
{
	int i;
	unsigned int mask;

	mask = 0;
	for (i = 0; i < 16; i++) {
		irq_desc_t *desc = irq_descp(i);
		unsigned int status;

		spin_lock_irq(&desc->lock);
		status = desc->status;

		if (status & IRQ_AUTODETECT) {
			if (!(status & IRQ_WAITING))
				mask |= 1 << i;

			desc->status = status & ~IRQ_AUTODETECT;
			desc->handler->shutdown(i);
		}
		spin_unlock_irq(&desc->lock);
	}
	up(&probe_sem);

	return mask & val;
}
EXPORT_SYMBOL(probe_irq_mask);

/**
 *	probe_irq_off	- end an interrupt autodetect
 *	@val: mask of potential interrupts (unused)
 *
 *	Scans the unused interrupt lines and returns the line which
 *	appears to have triggered the interrupt. If no interrupt was
 *	found then zero is returned. If more than one interrupt is
 *	found then minus the first candidate is returned to indicate
 *	their is doubt.
 *
 *	The interrupt probe logic state is returned to its previous
 *	value.
 *
 *	BUGS: When used in a module (which arguably shouldn't happen)
 *	nothing prevents two IRQ probe callers from overlapping. The
 *	results of this are non-optimal.
 */

int probe_irq_off(unsigned long val)
{
	int i, irq_found, nr_irqs;

	nr_irqs = 0;
	irq_found = 0;
	for (i = 0; i < NR_IRQS; i++) {
		irq_desc_t *desc = irq_descp(i);
		unsigned int status;

		spin_lock_irq(&desc->lock);
		status = desc->status;

		if (status & IRQ_AUTODETECT) {
			if (!(status & IRQ_WAITING)) {
				if (!nr_irqs)
					irq_found = i;
				nr_irqs++;
			}
			desc->status = status & ~IRQ_AUTODETECT;
			desc->handler->shutdown(i);
		}
		spin_unlock_irq(&desc->lock);
	}
	up(&probe_sem);

	if (nr_irqs > 1)
		irq_found = -irq_found;
	return irq_found;
}

EXPORT_SYMBOL(probe_irq_off);
#endif

int setup_irq(unsigned int irq, struct irqaction * new)
{
	int shared = 0;
	unsigned long flags;
	struct irqaction *old, **p;
	irq_desc_t *desc = irq_descp(irq);

#ifndef XEN
	if (desc->handler == &no_irq_type)
		return -ENOSYS;
	/*
	 * Some drivers like serial.c use request_irq() heavily,
	 * so we have to be careful not to interfere with a
	 * running system.
	 */
	if (new->flags & SA_SAMPLE_RANDOM) {
		/*
		 * This function might sleep, we want to call it first,
		 * outside of the atomic block.
		 * Yes, this might clear the entropy pool if the wrong
		 * driver is attempted to be loaded, without actually
		 * installing a new handler, but is this really a problem,
		 * only the sysadmin is able to do this.
		 */
		rand_initialize_irq(irq);
	}

	if (new->flags & SA_PERCPU_IRQ) {
		desc->status |= IRQ_PER_CPU;
		desc->handler = &irq_type_ia64_lsapic;
	}
#endif

	/*
	 * The following block of code has to be executed atomically
	 */
	spin_lock_irqsave(&desc->lock,flags);
	p = &desc->action;
	if ((old = *p) != NULL) {
#ifdef XEN
		if (1) {
		/* Can't share interrupts unless both agree to */
#else
		if (!(old->flags & new->flags & SA_SHIRQ)) {
#endif
			spin_unlock_irqrestore(&desc->lock,flags);
			return -EBUSY;
		}

#ifndef XEN
		/* add new interrupt at end of irq queue */
		do {
			p = &old->next;
			old = *p;
		} while (old);
		shared = 1;
#endif
	}

	*p = new;

#ifndef XEN
	if (!shared) {
#else
	{
#endif
		desc->depth = 0;
#ifdef XEN
		desc->status &= ~(IRQ_DISABLED | IRQ_INPROGRESS);
#else
		desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING | IRQ_INPROGRESS);
#endif
		desc->handler->startup(irq);
	}
	spin_unlock_irqrestore(&desc->lock,flags);

#ifndef XEN
	register_irq_proc(irq);
#endif
	return 0;
}

static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];

#ifdef CONFIG_SMP

static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];

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

static char irq_redir [NR_IRQS]; // = { [0 ... NR_IRQS-1] = 1 };

void set_irq_affinity_info (unsigned int irq, int hwid, int redir)
{
	cpumask_t mask = CPU_MASK_NONE;

	cpu_set(cpu_logical_id(hwid), mask);

	if (irq < NR_IRQS) {
		irq_affinity[irq] = mask;
		irq_redir[irq] = (char) (redir & 0xff);
	}
}

static int irq_affinity_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	int len = sprintf(page, "%s", irq_redir[(long)data] ? "r " : "");

	len += cpumask_scnprintf(page+len, count, irq_affinity[(long)data]);
	if (count - len < 2)
		return -EINVAL;
	len += sprintf(page + len, "\n");
	return len;
}

static int irq_affinity_write_proc (struct file *file, const char *buffer,
				    unsigned long count, void *data)
{
	unsigned int irq = (unsigned long) data;
	int full_count = count, err;
	cpumask_t new_value, tmp;
#	define R_PREFIX_LEN 16
	char rbuf[R_PREFIX_LEN];
	int rlen;
	int prelen;
	irq_desc_t *desc = irq_descp(irq);
	unsigned long flags;

	if (!desc->handler->set_affinity)
		return -EIO;

	/*
	 * If string being written starts with a prefix of 'r' or 'R'
	 * and some limited number of spaces, set IA64_IRQ_REDIRECTED.
	 * If more than (R_PREFIX_LEN - 2) spaces are passed, they won't
	 * all be trimmed as part of prelen, the untrimmed spaces will
	 * cause the hex parsing to fail, and this write() syscall will
	 * fail with EINVAL.
	 */

	if (!count)
		return -EINVAL;
	rlen = min(sizeof(rbuf)-1, count);
	if (copy_from_user(rbuf, buffer, rlen))
		return -EFAULT;
	rbuf[rlen] = 0;
	prelen = 0;
	if (tolower(*rbuf) == 'r') {
		prelen = strspn(rbuf, "Rr ");
		irq |= IA64_IRQ_REDIRECTED;
	}

	err = cpumask_parse(buffer+prelen, count-prelen, new_value);
	if (err)
		return err;

	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	cpus_and(tmp, new_value, cpu_online_map);
	if (cpus_empty(tmp))
		return -EINVAL;

	spin_lock_irqsave(&desc->lock, flags);
	pending_irq_cpumask[irq] = new_value;
	spin_unlock_irqrestore(&desc->lock, flags);

	return full_count;
}

void move_irq(int irq)
{
	/* note - we hold desc->lock */
	cpumask_t tmp;
	irq_desc_t *desc = irq_descp(irq);

	if (!cpus_empty(pending_irq_cpumask[irq])) {
		cpus_and(tmp, pending_irq_cpumask[irq], cpu_online_map);
		if (unlikely(!cpus_empty(tmp))) {
			desc->handler->set_affinity(irq, pending_irq_cpumask[irq]);
		}
		cpus_clear(pending_irq_cpumask[irq]);
	}
}


#endif /* CONFIG_SMP */

#ifdef CONFIG_HOTPLUG_CPU
unsigned int vectors_in_migration[NR_IRQS];

/*
 * Since cpu_online_map is already updated, we just need to check for
 * affinity that has zeros
 */
static void migrate_irqs(void)
{
	cpumask_t	mask;
	irq_desc_t *desc;
	int 		irq, new_cpu;

	for (irq=0; irq < NR_IRQS; irq++) {
		desc = irq_descp(irq);

		/*
		 * No handling for now.
		 * TBD: Implement a disable function so we can now
		 * tell CPU not to respond to these local intr sources.
		 * such as ITV,CPEI,MCA etc.
		 */
		if (desc->status == IRQ_PER_CPU)
			continue;

		cpus_and(mask, irq_affinity[irq], cpu_online_map);
		if (any_online_cpu(mask) == NR_CPUS) {
			/*
			 * Save it for phase 2 processing
			 */
			vectors_in_migration[irq] = irq;

			new_cpu = any_online_cpu(cpu_online_map);
			mask = cpumask_of_cpu(new_cpu);

			/*
			 * Al three are essential, currently WARN_ON.. maybe panic?
			 */
			if (desc->handler && desc->handler->disable &&
				desc->handler->enable && desc->handler->set_affinity) {
				desc->handler->disable(irq);
				desc->handler->set_affinity(irq, mask);
				desc->handler->enable(irq);
			} else {
				WARN_ON((!(desc->handler) || !(desc->handler->disable) ||
						!(desc->handler->enable) ||
						!(desc->handler->set_affinity)));
			}
		}
	}
}

void fixup_irqs(void)
{
	unsigned int irq;
	extern void ia64_process_pending_intr(void);

	ia64_set_itv(1<<16);
	/*
	 * Phase 1: Locate irq's bound to this cpu and
	 * relocate them for cpu removal.
	 */
	migrate_irqs();

	/*
	 * Phase 2: Perform interrupt processing for all entries reported in
	 * local APIC.
	 */
	ia64_process_pending_intr();

	/*
	 * Phase 3: Now handle any interrupts not captured in local APIC.
	 * This is to account for cases that device interrupted during the time the
	 * rte was being disabled and re-programmed.
	 */
	for (irq=0; irq < NR_IRQS; irq++) {
		if (vectors_in_migration[irq]) {
			vectors_in_migration[irq]=0;
			do_IRQ(irq, NULL);
		}
	}

	/*
	 * Now let processor die. We do irq disable and max_xtp() to
	 * ensure there is no more interrupts routed to this processor.
	 * But the local timer interrupt can have 1 pending which we
	 * take care in timer_interrupt().
	 */
	max_xtp();
	local_irq_disable();
}
#endif

#ifndef XEN
static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
	if (count - len < 2)
		return -EINVAL;
	len += sprintf(page + len, "\n");
	return len;
}

static int prof_cpu_mask_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	cpumask_t *mask = (cpumask_t *)data;
	unsigned long full_count = count, err;
	cpumask_t new_value;

	err = cpumask_parse(buffer, count, new_value);
	if (err)
		return err;

	*mask = new_value;
	return full_count;
}

#define MAX_NAMELEN 10

static void register_irq_proc (unsigned int irq)
{
	char name [MAX_NAMELEN];

	if (!root_irq_dir || (irq_descp(irq)->handler == &no_irq_type) || irq_dir[irq])
		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
	irq_dir[irq] = proc_mkdir(name, root_irq_dir);

#ifdef CONFIG_SMP
	{
		struct proc_dir_entry *entry;

		/* create /proc/irq/1234/smp_affinity */
		entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);

		if (entry) {
			entry->nlink = 1;
			entry->data = (void *)(long)irq;
			entry->read_proc = irq_affinity_read_proc;
			entry->write_proc = irq_affinity_write_proc;
		}

		smp_affinity_entry[irq] = entry;
	}
#endif
}

cpumask_t prof_cpu_mask = CPU_MASK_ALL;

void init_irq_proc (void)
{
	struct proc_dir_entry *entry;
	int i;

	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", 0);

	/* create /proc/irq/prof_cpu_mask */
	entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);

	if (!entry)
		return;

	entry->nlink = 1;
	entry->data = (void *)&prof_cpu_mask;
	entry->read_proc = prof_cpu_mask_read_proc;
	entry->write_proc = prof_cpu_mask_write_proc;

	/*
	 * Create entries for all existing IRQs.
	 */
	for (i = 0; i < NR_IRQS; i++) {
		if (irq_descp(i)->handler == &no_irq_type)
			continue;
		register_irq_proc(i);
	}
}
#endif


#ifdef XEN
/*
 * HANDLING OF GUEST-BOUND PHYSICAL IRQS
 */

#define IRQ_MAX_GUESTS 7
typedef struct {
    u8 nr_guests;
    u8 in_flight;
    u8 shareable;
    struct domain *guest[IRQ_MAX_GUESTS];
} irq_guest_action_t;

static void __do_IRQ_guest(int irq)
{
    irq_desc_t         *desc = &irq_desc[irq];
    irq_guest_action_t *action = (irq_guest_action_t *)desc->action;
    struct domain      *d;
    int                 i;

    for ( i = 0; i < action->nr_guests; i++ )
    {
        d = action->guest[i];
        if ( !test_and_set_bit(irq, &d->pirq_mask) )
            action->in_flight++;
        send_guest_pirq(d, irq);
    }
}

int pirq_guest_unmask(struct domain *d)
{
    irq_desc_t    *desc;
    int            i, j, pirq;
    u32            m;
    shared_info_t *s = d->shared_info;

    for ( i = 0; i < ARRAY_SIZE(d->pirq_mask); i++ )
    {
        m = d->pirq_mask[i];
        while ( (j = ffs(m)) != 0 )
        {
            m &= ~(1 << --j);
            pirq = (i << 5) + j;
            desc = &irq_desc[pirq];
            spin_lock_irq(&desc->lock);
            if ( !test_bit(d->pirq_to_evtchn[pirq], &s->evtchn_mask[0]) &&
                 test_and_clear_bit(pirq, &d->pirq_mask) &&
                 (--((irq_guest_action_t *)desc->action)->in_flight == 0) )
                desc->handler->end(pirq);
            spin_unlock_irq(&desc->lock);
        }
    }

    return 0;
}

int pirq_guest_bind(struct exec_domain *d, int irq, int will_share)
{
    irq_desc_t         *desc = &irq_desc[irq];
    irq_guest_action_t *action;
    unsigned long       flags;
    int                 rc = 0;

    if ( !IS_CAPABLE_PHYSDEV(d->domain) )
        return -EPERM;

    spin_lock_irqsave(&desc->lock, flags);

    action = (irq_guest_action_t *)desc->action;

    if ( !(desc->status & IRQ_GUEST) )
    {
        if ( desc->action != NULL )
        {
            DPRINTK("Cannot bind IRQ %d to guest. In use by '%s'.\n",
                    irq, desc->action->name);
            rc = -EBUSY;
            goto out;
        }

        action = xmalloc(irq_guest_action_t);
        if ( (desc->action = (struct irqaction *)action) == NULL )
        {
            DPRINTK("Cannot bind IRQ %d to guest. Out of memory.\n", irq);
            rc = -ENOMEM;
            goto out;
        }

        action->nr_guests = 0;
        action->in_flight = 0;
        action->shareable = will_share;
        
        desc->depth = 0;
        desc->status |= IRQ_GUEST;
        desc->status &= ~IRQ_DISABLED;
        desc->handler->startup(irq);

        /* Attempt to bind the interrupt target to the correct CPU. */
#if 0 /* FIXME CONFIG_SMP ??? */
        if ( desc->handler->set_affinity != NULL )
            desc->handler->set_affinity(
                irq, apicid_to_phys_cpu_present(d->processor));
#endif
    }
    else if ( !will_share || !action->shareable )
    {
        DPRINTK("Cannot bind IRQ %d to guest. Will not share with others.\n",
                irq);
        rc = -EBUSY;
        goto out;
    }

    if ( action->nr_guests == IRQ_MAX_GUESTS )
    {
        DPRINTK("Cannot bind IRQ %d to guest. Already at max share.\n", irq);
        rc = -EBUSY;
        goto out;
    }

    action->guest[action->nr_guests++] = d;

 out:
    spin_unlock_irqrestore(&desc->lock, flags);
    return rc;
}

int pirq_guest_unbind(struct domain *d, int irq)
{
    irq_desc_t         *desc = &irq_desc[irq];
    irq_guest_action_t *action;
    unsigned long       flags;
    int                 i;

    spin_lock_irqsave(&desc->lock, flags);

    action = (irq_guest_action_t *)desc->action;

    if ( test_and_clear_bit(irq, &d->pirq_mask) &&
         (--action->in_flight == 0) )
        desc->handler->end(irq);

    if ( action->nr_guests == 1 )
    {
        desc->action = NULL;
        xfree(action);
        desc->depth   = 1;
        desc->status |= IRQ_DISABLED;
        desc->status &= ~IRQ_GUEST;
        desc->handler->shutdown(irq);
    }
    else
    {
        i = 0;
        while ( action->guest[i] != d )
            i++;
        memmove(&action->guest[i], &action->guest[i+1], IRQ_MAX_GUESTS-i-1);
        action->nr_guests--;
    }

    spin_unlock_irqrestore(&desc->lock, flags);    
    return 0;
}

int pirq_guest_bindable(int irq, int will_share)
{
    irq_desc_t         *desc = &irq_desc[irq];
    irq_guest_action_t *action;
    unsigned long       flags;
    int                 okay;

    spin_lock_irqsave(&desc->lock, flags);

    action = (irq_guest_action_t *)desc->action;

    /*
     * To be bindable the IRQ must either be not currently bound (1), or
     * it must be shareable (2) and not at its share limit (3).
     */
    okay = ((!(desc->status & IRQ_GUEST) && (action == NULL)) || /* 1 */
            (action->shareable && will_share &&                  /* 2 */
             (action->nr_guests != IRQ_MAX_GUESTS)));            /* 3 */

    spin_unlock_irqrestore(&desc->lock, flags);
    return okay;
}
#endif

#ifdef XEN
#ifdef IA64
// this is a temporary hack until real console input is implemented
irqreturn_t guest_forward_keyboard_input(int irq, void *nada, struct pt_regs *regs)
{
	domain_pend_keyboard_interrupt(irq);
}

void serial_input_init(void)
{
	int retval;
	int irq = 0x30;	// FIXME

	retval = request_irq(irq,guest_forward_keyboard_input,SA_INTERRUPT,"siminput",NULL);
	if (retval) {
		printk("serial_input_init: broken request_irq call\n");
		while(1);
	}
}
#endif
#endif