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