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
  18 static atomic_t irq_err_count;
  19 void 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
  25 static 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
  36 int 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
  72 static 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
  84 static inline void check_stack_overflow(int irq) { }
  85 #endif
  86
  87 #ifndef CONFIG_IPIPE
  88 static 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
 107 static 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
 118 asmlinkage 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
 142 void __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 }