/*
 *	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.
 */

#include <asm/delay.h>
#include <asm/uaccess.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>

/*
 * 'what should we do if we get a hw irq event on an illegal vector'.
 * each architecture has to answer this themselves.
 */
void ack_bad_irq(unsigned int irq)
{
	printk(KERN_ERR "Unexpected irq vector 0x%x on CPU %u!\n", irq, smp_processor_id());
}

#ifdef CONFIG_IA64_GENERIC
unsigned int __ia64_local_vector_to_irq (ia64_vector vec)
{
	return (unsigned int) vec;
}
#endif

/*
 * Interrupt statistics:
 */

atomic_t irq_err_count;

/*
 * /proc/interrupts printing:
 */

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

	if (i == 0) {
		seq_printf(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) {
		spin_lock_irqsave(&irq_desc[i].lock, flags);
		action = irq_desc[i].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", irq_desc[i].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(&irq_desc[i].lock, flags);
	} else if (i == NR_IRQS)
		seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
	return 0;
}

#ifdef CONFIG_SMP
/*
 * This is updated when the user sets irq affinity via /proc
 */
static cpumask_t __cacheline_aligned pending_irq_cpumask[NR_IRQS];
static unsigned long pending_irq_redir[BITS_TO_LONGS(NR_IRQS)];

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

/*
 * Arch specific routine for deferred write to iosapic rte to reprogram
 * intr destination.
 */
void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
{
	pending_irq_cpumask[irq] = mask_val;
}

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);
	}
}


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

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

	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 | (redir ? IA64_IRQ_REDIRECTED : 0),
						    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