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