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                 raw_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                 raw_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
  69 static 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
  81 static inline void check_stack_overflow(int irq) { }
  82 #endif
  83
  84 #ifndef CONFIG_IPIPE
  85 static 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
 104 static 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
 115 asmlinkage 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
 139 void __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 }