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irq.c

/*
 * linux/arch/xtensa/kernel/irq.c
 *
 * Xtensa built-in interrupt controller and some generic functions copied
 * from i386.
 *
 * Copyright (C) 2002 - 2006 Tensilica, Inc.
 * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 *
 * Chris Zankel <chris@zankel.net>
 * Kevin Chea
 *
 */

#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel_stat.h>

#include <asm/uaccess.h>
#include <asm/platform.h>

static unsigned int cached_irq_mask;

atomic_t irq_err_count;

/*
 * '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("unexpected IRQ trap at vector %02x\n", irq);
}

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */

asmlinkage void do_IRQ(int irq, struct pt_regs *regs)
{
      struct pt_regs *old_regs = set_irq_regs(regs);
      struct irq_desc *desc = irq_desc + irq;

      if (irq >= NR_IRQS) {
            printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
                        __FUNCTION__, irq);
      }

      irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
      /* Debugging check for stack overflow: is there less than 1KB free? */
      {
            unsigned long sp;

            __asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
            sp &= THREAD_SIZE - 1;

            if (unlikely(sp < (sizeof(thread_info) + 1024)))
                  printk("Stack overflow in do_IRQ: %ld\n",
                         sp - sizeof(struct thread_info));
      }
#endif
      desc->handle_irq(irq, desc);

      irq_exit();
      set_irq_regs(old_regs);
}

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

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_each_online_cpu(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_each_online_cpu(j)
                  seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
#endif
            seq_printf(p, " %14s", irq_desc[i].chip->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, "NMI: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", nmi_count(j));
            seq_putc(p, '\n');
            seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
      }
      return 0;
}

static void xtensa_irq_mask(unsigned int irq)
{
      cached_irq_mask &= ~(1 << irq);
      set_sr (cached_irq_mask, INTENABLE);
}

static void xtensa_irq_unmask(unsigned int irq)
{
      cached_irq_mask |= 1 << irq;
      set_sr (cached_irq_mask, INTENABLE);
}

static void xtensa_irq_ack(unsigned int irq)
{
      set_sr(1 << irq, INTCLEAR);
}

static int xtensa_irq_retrigger(unsigned int irq)
{
      set_sr (1 << irq, INTSET);
      return 1;
}


static struct irq_chip xtensa_irq_chip = {
      .name       = "xtensa",
      .mask       = xtensa_irq_mask,
      .unmask           = xtensa_irq_unmask,
      .ack        = xtensa_irq_ack,
      .retrigger  = xtensa_irq_retrigger,
};

void __init init_IRQ(void)
{
      int index;

      for (index = 0; index < XTENSA_NR_IRQS; index++) {
            int mask = 1 << index;

            if (mask & XCHAL_INTTYPE_MASK_SOFTWARE)
                  set_irq_chip_and_handler(index, &xtensa_irq_chip,
                                     handle_simple_irq);

            else if (mask & XCHAL_INTTYPE_MASK_EXTERN_EDGE)
                  set_irq_chip_and_handler(index, &xtensa_irq_chip,
                                     handle_edge_irq);

            else if (mask & XCHAL_INTTYPE_MASK_EXTERN_LEVEL)
                  set_irq_chip_and_handler(index, &xtensa_irq_chip,
                                     handle_level_irq);

            else if (mask & XCHAL_INTTYPE_MASK_TIMER)
                  set_irq_chip_and_handler(index, &xtensa_irq_chip,
                                     handle_edge_irq);

            else  /* XCHAL_INTTYPE_MASK_WRITE_ERROR */
                  /* XCHAL_INTTYPE_MASK_NMI */

                  set_irq_chip_and_handler(index, &xtensa_irq_chip,
                                     handle_level_irq);
      }

      cached_irq_mask = 0;
}

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