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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 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_cpu(j).irqs[i]);
            }
#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)
{
      cpumask_t mask = CPU_MASK_NONE;

      cpu_set(cpu_logical_id(hwid), mask);

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

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

#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_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;

            cpus_and(mask, irq_desc[irq].affinity, 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->chip && desc->chip->disable &&
                        desc->chip->enable && desc->chip->set_affinity) {
                        desc->chip->disable(irq);
                        desc->chip->set_affinity(irq, mask);
                        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 void ia64_disable_timer(void);
      extern volatile int time_keeper_id;

      ia64_disable_timer();

      /*
       * Find a new timesync master
       */
      if (smp_processor_id() == time_keeper_id) {
            time_keeper_id = first_cpu(cpu_online_map);
            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

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