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   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  * 'what should we do if we get a hw irq event on an illegal vector'.
  31  * each architecture has to answer this themselves.
  32  */
  33 void ack_bad_irq(unsigned int irq)
  34 {
  35           printk("unexpected IRQ trap at vector %02x\n", irq);
  36 }
  37
  38 /*
  39  * do_IRQ handles all normal device IRQ's (the special
  40  * SMP cross-CPU interrupts have their own specific
  41  * handlers).
  42  */
  43
  44 asmlinkage void do_IRQ(int irq, struct pt_regs *regs)
  45 {
  46         struct pt_regs *old_regs = set_irq_regs(regs);
  47         struct irq_desc *desc = irq_desc + irq;
  48
  49         if (irq >= NR_IRQS) {
  50                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
  51                                 __func__, irq);
  52         }
  53
  54         irq_enter();
  55
  56 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  57         /* Debugging check for stack overflow: is there less than 1KB free? */
  58         {
  59                 unsigned long sp;
  60
  61                 __asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
  62                 sp &= THREAD_SIZE - 1;
  63
  64                 if (unlikely(sp < (sizeof(thread_info) + 1024)))
  65                         printk("Stack overflow in do_IRQ: %ld\n",
  66                                sp - sizeof(struct thread_info));
  67         }
  68 #endif
  69         desc->handle_irq(irq, desc);
  70
  71         irq_exit();
  72         set_irq_regs(old_regs);
  73 }
  74
  75 /*
  76  * Generic, controller-independent functions:
  77  */
  78
  79 int show_interrupts(struct seq_file *p, void *v)
  80 {
  81         int i = *(loff_t *) v, j;
  82         struct irqaction * action;
  83         unsigned long flags;
  84
  85         if (i == 0) {
  86                 seq_printf(p, "           ");
  87                 for_each_online_cpu(j)
  88                         seq_printf(p, "CPU%d       ",j);
  89                 seq_putc(p, '\n');
  90         }
  91
  92         if (i < NR_IRQS) {
  93                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  94                 action = irq_desc[i].action;
  95                 if (!action)
  96                         goto skip;
  97                 seq_printf(p, "%3d: ",i);
  98 #ifndef CONFIG_SMP
  99                 seq_printf(p, "%10u ", kstat_irqs(i));
 100 #else
 101                 for_each_online_cpu(j)
 102                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 103 #endif
 104                 seq_printf(p, " %14s", irq_desc[i].chip->typename);
 105                 seq_printf(p, "  %s", action->name);
 106
 107                 for (action=action->next; action; action = action->next)
 108                         seq_printf(p, ", %s", action->name);
 109
 110                 seq_putc(p, '\n');
 111 skip:
 112                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 113         } else if (i == NR_IRQS) {
 114                 seq_printf(p, "NMI: ");
 115                 for_each_online_cpu(j)
 116                         seq_printf(p, "%10u ", nmi_count(j));
 117                 seq_putc(p, '\n');
 118                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 119         }
 120         return 0;
 121 }
 122
 123 static void xtensa_irq_mask(unsigned int irq)
 124 {
 125         cached_irq_mask &= ~(1 << irq);
 126         set_sr (cached_irq_mask, INTENABLE);
 127 }
 128
 129 static void xtensa_irq_unmask(unsigned int irq)
 130 {
 131         cached_irq_mask |= 1 << irq;
 132         set_sr (cached_irq_mask, INTENABLE);
 133 }
 134
 135 static void xtensa_irq_enable(unsigned int irq)
 136 {
 137         variant_irq_enable(irq);
 138         xtensa_irq_unmask(irq);
 139 }
 140
 141 static void xtensa_irq_disable(unsigned int irq)
 142 {
 143         xtensa_irq_mask(irq);
 144         variant_irq_disable(irq);
 145 }
 146
 147 static void xtensa_irq_ack(unsigned int irq)
 148 {
 149         set_sr(1 << irq, INTCLEAR);
 150 }
 151
 152 static int xtensa_irq_retrigger(unsigned int irq)
 153 {
 154         set_sr (1 << irq, INTSET);
 155         return 1;
 156 }
 157
 158
 159 static struct irq_chip xtensa_irq_chip = {
 160         .name           = "xtensa",
 161         .enable         = xtensa_irq_enable,
 162         .disable        = xtensa_irq_disable,
 163         .mask           = xtensa_irq_mask,
 164         .unmask         = xtensa_irq_unmask,
 165         .ack            = xtensa_irq_ack,
 166         .retrigger      = xtensa_irq_retrigger,
 167 };
 168
 169 void __init init_IRQ(void)
 170 {
 171         int index;
 172
 173         for (index = 0; index < XTENSA_NR_IRQS; index++) {
 174                 int mask = 1 << index;
 175
 176                 if (mask & XCHAL_INTTYPE_MASK_SOFTWARE)
 177                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 178                                                  handle_simple_irq);
 179
 180                 else if (mask & XCHAL_INTTYPE_MASK_EXTERN_EDGE)
 181                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 182                                                  handle_edge_irq);
 183
 184                 else if (mask & XCHAL_INTTYPE_MASK_EXTERN_LEVEL)
 185                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 186                                                  handle_level_irq);
 187
 188                 else if (mask & XCHAL_INTTYPE_MASK_TIMER)
 189                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 190                                                  handle_edge_irq);
 191
 192                 else    /* XCHAL_INTTYPE_MASK_WRITE_ERROR */
 193                         /* XCHAL_INTTYPE_MASK_NMI */
 194
 195                         set_irq_chip_and_handler(index, &xtensa_irq_chip,
 196                                                  handle_level_irq);
 197         }
 198
 199         cached_irq_mask = 0;
 200
 201         variant_init_irq();
 202 }