LXR linux/arch/blackfin/kernel/irqchip.c

   1/*
   2 * Copyright 2005-2009 Analog Devices Inc.
   3 *
   4 * Licensed under the GPL-2 or later
   5 */
   6
   7#include <linux/kernel_stat.h>
   8#include <linux/module.h>
   9#include <linux/random.h>
  10#include <linux/seq_file.h>
  11#include <linux/kallsyms.h>
  12#include <linux/interrupt.h>
  13#include <linux/irq.h>
  14#include <asm/irq_handler.h>
  15#include <asm/trace.h>
  16#include <asm/pda.h>
  17
  18static atomic_t irq_err_count;
  19void ack_bad_irq(unsigned int irq)
  20{
  21        atomic_inc(&irq_err_count);
  22        printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  23}
  24
  25static struct irq_desc bad_irq_desc = {
  26        .handle_irq = handle_bad_irq,
  27        .lock = __RAW_SPIN_LOCK_UNLOCKED(bad_irq_desc.lock),
  28};
  29
  30#ifdef CONFIG_CPUMASK_OFFSTACK
  31/* We are not allocating a variable-sized bad_irq_desc.affinity */
  32#error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
  33#endif
  34
  35#ifdef CONFIG_PROC_FS
  36int show_interrupts(struct seq_file *p, void *v)
  37{
  38        int i = *(loff_t *) v, j;
  39        struct irqaction *action;
  40        unsigned long flags;
  41
  42        if (i < NR_IRQS) {
  43                struct irq_desc *desc = irq_to_desc(i);
  44
  45                raw_spin_lock_irqsave(&desc->lock, flags);
  46                action = desc->action;
  47                if (!action)
  48                        goto skip;
  49                seq_printf(p, "%3d: ", i);
  50                for_each_online_cpu(j)
  51                        seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  52                seq_printf(p, " %8s", irq_desc_get_chip(desc)->name);
  53                seq_printf(p, "  %s", action->name);
  54                for (action = action->next; action; action = action->next)
  55                        seq_printf(p, "  %s", action->name);
  56
  57                seq_putc(p, '\n');
  58 skip:
  59                raw_spin_unlock_irqrestore(&desc->lock, flags);
  60        } else if (i == NR_IRQS) {
  61                seq_printf(p, "NMI: ");
  62                for_each_online_cpu(j)
  63                        seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
  64                seq_printf(p, "     CORE  Non Maskable Interrupt\n");
  65                seq_printf(p, "Err: %10u\n",  atomic_read(&irq_err_count));
  66        }
  67        return 0;
  68}
  69#endif
  70
  71#ifdef CONFIG_DEBUG_STACKOVERFLOW
  72static void check_stack_overflow(int irq)
  73{
  74        /* Debugging check for stack overflow: is there less than STACK_WARN free? */
  75        long sp = __get_SP() & (THREAD_SIZE - 1);
  76
  77        if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
  78                dump_stack();
  79                pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
  80                        irq, sp - sizeof(struct thread_info));
  81        }
  82}
  83#else
  84static inline void check_stack_overflow(int irq) { }
  85#endif
  86
  87#ifndef CONFIG_IPIPE
  88static void maybe_lower_to_irq14(void)
  89{
  90        unsigned short pending, other_ints;
  91
  92        /*
  93         * If we're the only interrupt running (ignoring IRQ15 which
  94         * is for syscalls), lower our priority to IRQ14 so that
  95         * softirqs run at that level.  If there's another,
  96         * lower-level interrupt, irq_exit will defer softirqs to
  97         * that. If the interrupt pipeline is enabled, we are already
  98         * running at IRQ14 priority, so we don't need this code.
  99         */
 100        CSYNC();
 101        pending = bfin_read_IPEND() & ~0x8000;
 102        other_ints = pending & (pending - 1);
 103        if (other_ints == 0)
 104                lower_to_irq14();
 105}
 106#else
 107static inline void maybe_lower_to_irq14(void) { }
 108#endif
 109
 110/*
 111 * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 112 * come via this function.  Instead, they should provide their
 113 * own 'handler'
 114 */
 115#ifdef CONFIG_DO_IRQ_L1
 116__attribute__((l1_text))
 117#endif
 118asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 119{
 120        struct pt_regs *old_regs = set_irq_regs(regs);
 121
 122        irq_enter();
 123
 124        check_stack_overflow(irq);
 125
 126        /*
 127         * Some hardware gives randomly wrong interrupts.  Rather
 128         * than crashing, do something sensible.
 129         */
 130        if (irq >= NR_IRQS)
 131                handle_bad_irq(irq, &bad_irq_desc);
 132        else
 133                generic_handle_irq(irq);
 134
 135        maybe_lower_to_irq14();
 136
 137        irq_exit();
 138
 139        set_irq_regs(old_regs);
 140}
 141
 142void __init init_IRQ(void)
 143{
 144        init_arch_irq();
 145
 146#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 147        /* Now that evt_ivhw is set up, turn this on */
 148        trace_buff_offset = 0;
 149        bfin_write_TBUFCTL(BFIN_TRACE_ON);
 150        printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 151          1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 152#endif
 153}
 154