/*
 *      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 IRQs 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 losing 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
ia64_vector __ia64_irq_to_vector(int irq)
{
        return irq_cfg[irq].vector;
}

unsigned int __ia64_local_vector_to_irq (ia64_vector vec)
{
        return __get_cpu_var(vector_irq)[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) {
                char cpuname[16];
                seq_printf(p, "     ");
                for_each_online_cpu(j) {
                        snprintf(cpuname, 10, "CPU%d", j);
                        seq_printf(p, "%10s ", cpuname);
                }
                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_each_online_cpu(j) {
                        seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
                }
#endif
                seq_printf(p, " %14s", irq_desc[i].chip->name);
                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
static char irq_redir [NR_IRQS]; // = { [0 ... NR_IRQS-1] = 1 };

void set_irq_affinity_info (unsigned int irq, int hwid, int redir)
{
        if (irq < NR_IRQS) {
                cpumask_copy(irq_desc[irq].affinity,
                             cpumask_of(cpu_logical_id(hwid)));
                irq_redir[irq] = (char) (redir & 0xff);
        }
}

bool is_affinity_mask_valid(const struct cpumask *cpumask)
{
        if (ia64_platform_is("sn2")) {
                /* Only allow one CPU to be specified in the smp_affinity mask */
                if (cpumask_weight(cpumask) != 1)
                        return false;
        }
        return true;
}

#endif /* CONFIG_SMP */

#ifdef CONFIG_HOTPLUG_CPU
unsigned int vectors_in_migration[NR_IRQS];

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

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

                if (desc->status == IRQ_DISABLED)
                        continue;

                /*
                 * 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;

                if (cpumask_any_and(irq_desc[irq].affinity, cpu_online_mask)
                    >= nr_cpu_ids) {
                        /*
                         * Save it for phase 2 processing
                         */
                        vectors_in_migration[irq] = irq;

                        new_cpu = cpumask_any(cpu_online_mask);

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

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

        /* Mask ITV to disable timer */
        ia64_set_itv(1 << 16);

        /*
         * Find a new timesync master
         */
        if (smp_processor_id() == time_keeper_id) {
                time_keeper_id = cpumask_first(cpu_online_mask);
                printk ("CPU %d is now promoted to time-keeper master\n", time_keeper_id);
        }

        /*
         * Phase 1: Locate IRQs 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]) {
                        struct pt_regs *old_regs = set_irq_regs(NULL);

                        vectors_in_migration[irq]=0;
                        generic_handle_irq(irq);
                        set_irq_regs(old_regs);
                }
        }

        /*
         * 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