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
  17 static atomic_t irq_err_count;
  18 void 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
  24 static struct irq_desc bad_irq_desc = {
  25         .handle_irq = handle_bad_irq,
  26         .lock = __RAW_SPIN_LOCK_UNLOCKED(bad_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
  35 int 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                 struct irq_desc *desc = irq_to_desc(i);
  43
  44                 raw_spin_lock_irqsave(&desc->lock, flags);
  45                 action = desc->action;
  46                 if (!action)
  47                         goto skip;
  48                 seq_printf(p, "%3d: ", i);
  49                 for_each_online_cpu(j)
  50                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  51                 seq_printf(p, " %8s", get_irq_desc_chip(desc)->name);
  52                 seq_printf(p, "  %s", action->name);
  53                 for (action = action->next; action; action = action->next)
  54                         seq_printf(p, "  %s", action->name);
  55
  56                 seq_putc(p, '\n');
  57  skip:
  58                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  59         } else if (i == NR_IRQS) {
  60                 seq_printf(p, "NMI: ");
  61                 for_each_online_cpu(j)
  62                         seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
  63                 seq_printf(p, "     CORE  Non Maskable Interrupt\n");
  64                 seq_printf(p, "Err: %10u\n",  atomic_read(&irq_err_count));
  65         }
  66         return 0;
  67 }
  68 #endif
  69
  70 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  71 static void check_stack_overflow(int irq)
  72 {
  73         /* Debugging check for stack overflow: is there less than STACK_WARN free? */
  74         long sp = __get_SP() & (THREAD_SIZE - 1);
  75
  76         if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
  77                 dump_stack();
  78                 pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
  79                         irq, sp - sizeof(struct thread_info));
  80         }
  81 }
  82 #else
  83 static inline void check_stack_overflow(int irq) { }
  84 #endif
  85
  86 #ifndef CONFIG_IPIPE
  87 static void maybe_lower_to_irq14(void)
  88 {
  89         unsigned short pending, other_ints;
  90
  91         /*
  92          * If we're the only interrupt running (ignoring IRQ15 which
  93          * is for syscalls), lower our priority to IRQ14 so that
  94          * softirqs run at that level.  If there's another,
  95          * lower-level interrupt, irq_exit will defer softirqs to
  96          * that. If the interrupt pipeline is enabled, we are already
  97          * running at IRQ14 priority, so we don't need this code.
  98          */
  99         CSYNC();
 100         pending = bfin_read_IPEND() & ~0x8000;
 101         other_ints = pending & (pending - 1);
 102         if (other_ints == 0)
 103                 lower_to_irq14();
 104 }
 105 #else
 106 static inline void maybe_lower_to_irq14(void) { }
 107 #endif
 108
 109 /*
 110  * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 111  * come via this function.  Instead, they should provide their
 112  * own 'handler'
 113  */
 114 #ifdef CONFIG_DO_IRQ_L1
 115 __attribute__((l1_text))
 116 #endif
 117 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 118 {
 119         struct pt_regs *old_regs = set_irq_regs(regs);
 120
 121         irq_enter();
 122
 123         check_stack_overflow(irq);
 124
 125         /*
 126          * Some hardware gives randomly wrong interrupts.  Rather
 127          * than crashing, do something sensible.
 128          */
 129         if (irq >= NR_IRQS)
 130                 handle_bad_irq(irq, &bad_irq_desc);
 131         else
 132                 generic_handle_irq(irq);
 133
 134         maybe_lower_to_irq14();
 135
 136         irq_exit();
 137
 138         set_irq_regs(old_regs);
 139 }
 140
 141 void __init init_IRQ(void)
 142 {
 143         init_arch_irq();
 144
 145 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 146         /* Now that evt_ivhw is set up, turn this on */
 147         trace_buff_offset = 0;
 148         bfin_write_TBUFCTL(BFIN_TRACE_ON);
 149         printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 150           1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 151 #endif
 152 }