arch/xtensa/kernel/irq.c

   1 /*
   2  * linux/arch/xtensa/kernel/irq.c
   3  *
   4  * Xtensa built-in interrupt controller and some generic functions copied
   5  * from i386.
   6  *
   7  * Copyright (C) 2002 - 2006 Tensilica, Inc.
   8  * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   9  *
  10  *
  11  * Chris Zankel <chris@zankel.net>
  12  * Kevin Chea
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/irq.h>
  20 #include <linux/kernel_stat.h>
  21
  22 #include <asm/uaccess.h>
  23 #include <asm/platform.h>
  24
  25 static unsigned int cached_irq_mask;
  26
  27 atomic_t irq_err_count;
  28
  29 /*
  30  * do_IRQ handles all normal device IRQ's (the special
  31  * SMP cross-CPU interrupts have their own specific
  32  * handlers).
  33  */
  34
  35 asmlinkage void do_IRQ(int irq, struct pt_regs *regs)
  36 {
  37         struct pt_regs *old_regs = set_irq_regs(regs);
  38         struct irq_desc *desc = irq_desc + irq;
  39
  40         if (irq >= NR_IRQS) {
  41                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
  42                                 __func__, irq);
  43         }
  44
  45         irq_enter();
  46
  47 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  48         /* Debugging check for stack overflow: is there less than 1KB free? */
  49         {
  50                 unsigned long sp;
  51
  52                 __asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
  53                 sp &= THREAD_SIZE - 1;
  54
  55                 if (unlikely(sp < (sizeof(thread_info) + 1024)))
  56                         printk("Stack overflow in do_IRQ: %ld\n",
  57                                sp - sizeof(struct thread_info));
  58         }
  59 #endif
  60         desc->handle_irq(irq, desc);
  61
  62         irq_exit();
  63         set_irq_regs(old_regs);
  64 }
  65
  66 /*
  67  * Generic, controller-independent functions:
  68  */
  69
  70 int show_interrupts(struct seq_file *p, void *v)
  71 {
  72         int i = *(loff_t *) v, j;
  73         struct irqaction * action;
  74         unsigned long flags;
  75
  76         if (i == 0) {
  77                 seq_printf(p, "           ");
  78                 for_each_online_cpu(j)
  79                         seq_printf(p, "CPU%d       ",j);
  80                 seq_putc(p, '\n');
  81         }
  82
  83         if (i < NR_IRQS) {
  84                 raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
  85                 action = irq_desc[i].action;
  86                 if (!action)
  87                         goto skip;
  88                 seq_printf(p, "%3d: ",i);
  89 #ifndef CONFIG_SMP
  90                 seq_printf(p, "%10u ", kstat_irqs(i));
  91 #else
  92                 for_each_online_cpu(j)
  93                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  94 #endif
  95                 seq_printf(p, " %14s", irq_desc[i].chip->typename);
  96                 seq_printf(p, "  %s", action->name);
  97
  98                 for (action=action->next; action; action = action->next)
  99                         seq_printf(p, ", %s", action->name);
 100
 101                 seq_putc(p, '\n');
 102 skip:
 103                 raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 104         } else if (i == NR_IRQS) {
 105                 seq_printf(p, "NMI: ");
 106                 for_each_online_cpu(j)
 107                         seq_printf(p, "%10u ", nmi_count(j));
 108                 seq_putc(p, '\n');
 109                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 110         }
 111         return 0;
 112 }
 113
 114 static void xtensa_irq_mask(unsigned int irq)
 115 {
 116         cached_irq_mask &= ~(1 << irq);
 117         set_sr (cached_irq_mask, INTENABLE);
 118 }
 119
 120 static void xtensa_irq_unmask(unsigned int irq)
 121 {
 122         cached_irq_mask |= 1 << irq;
 123         set_sr (cached_irq_mask, INTENABLE);
 124 }
 125
 126 static void xtensa_irq_enable(unsigned int irq)
 127 {
 128         variant_irq_enable(irq);
 129         xtensa_irq_unmask(irq);
 130 }
 131
 132 static void xtensa_irq_disable(unsigned int irq)
 133 {
 134         xtensa_irq_mask(irq);
 135         variant_irq_disable(irq);
 136 }
 137
 138 static void xtensa_irq_ack(unsigned int irq)
 139 {
 140         set_sr(1 << irq, INTCLEAR);
 141 }
 142
 143 static int xtensa_irq_retrigger(unsigned int irq)
 144 {
 145         set_sr (1 << irq, INTSET);
 146         return 1;
 147 }
 148
 149
 150 static struct irq_chip xtensa_irq_chip = {
 151         .name           = "xtensa",
 152         .enable         = xtensa_irq_enable,
 153         .disable        = xtensa_irq_disable,
 154         .mask           = xtensa_irq_mask,
 155         .unmask         = xtensa_irq_unmask,
 156         .ack            = xtensa_irq_ack,
 157         .retrigger      = xtensa_irq_retrigger,
 158 };
 159
 160 void __init init_IRQ(void)
 161 {
 162         int index;
 163
 164         for (index = 0; index < XTENSA_NR_IRQS; index++) {
 165                 int mask = 1 << index;
 166
 167                 if (mask & XCHAL_INTTYPE_MASK_SOFTWARE)
 168                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 169                                                  handle_simple_irq);
 170
 171                 else if (mask & XCHAL_INTTYPE_MASK_EXTERN_EDGE)
 172                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 173                                                  handle_edge_irq);
 174
 175                 else if (mask & XCHAL_INTTYPE_MASK_EXTERN_LEVEL)
 176                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 177                                                  handle_level_irq);
 178
 179                 else if (mask & XCHAL_INTTYPE_MASK_TIMER)
 180                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 181                                                  handle_edge_irq);
 182
 183                 else    /* XCHAL_INTTYPE_MASK_WRITE_ERROR */
 184                         /* XCHAL_INTTYPE_MASK_NMI */
 185
 186                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 187                                                  handle_level_irq);
 188         }
 189
 190         cached_irq_mask = 0;
 191
 192         variant_init_irq();
 193 }