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 - 2005 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 void enable_xtensa_irq(unsigned int irq);
  26 static void disable_xtensa_irq(unsigned int irq);
  27 static void mask_and_ack_xtensa(unsigned int irq);
  28 static void end_xtensa_irq(unsigned int irq);
  29
  30 static unsigned int cached_irq_mask;
  31
  32 atomic_t irq_err_count;
  33
  34 /*
  35  * 'what should we do if we get a hw irq event on an illegal vector'.
  36  * each architecture has to answer this themselves.
  37  */
  38 void ack_bad_irq(unsigned int irq)
  39 {
  40           printk("unexpected IRQ trap at vector %02x\n", irq);
  41 }
  42
  43 /*
  44  * do_IRQ handles all normal device IRQ's (the special
  45  * SMP cross-CPU interrupts have their own specific
  46  * handlers).
  47  */
  48
  49 unsigned int  do_IRQ(int irq, struct pt_regs *regs)
  50 {
  51         irq_enter();
  52
  53 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  54         /* Debugging check for stack overflow: is there less than 1KB free? */
  55         {
  56                 unsigned long sp;
  57
  58                 __asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
  59                 sp &= THREAD_SIZE - 1;
  60
  61                 if (unlikely(sp < (sizeof(thread_info) + 1024)))
  62                         printk("Stack overflow in do_IRQ: %ld\n",
  63                                sp - sizeof(struct thread_info));
  64         }
  65 #endif
  66         __do_IRQ(irq, regs);
  67         irq_exit();
  68
  69         return 1;
  70 }
  71
  72 /*
  73  * Generic, controller-independent functions:
  74  */
  75
  76 int show_interrupts(struct seq_file *p, void *v)
  77 {
  78         int i = *(loff_t *) v, j;
  79         struct irqaction * action;
  80         unsigned long flags;
  81
  82         if (i == 0) {
  83                 seq_printf(p, "           ");
  84                 for_each_online_cpu(j)
  85                         seq_printf(p, "CPU%d       ",j);
  86                 seq_putc(p, '\n');
  87         }
  88
  89         if (i < NR_IRQS) {
  90                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  91                 action = irq_desc[i].action;
  92                 if (!action)
  93                         goto skip;
  94                 seq_printf(p, "%3d: ",i);
  95 #ifndef CONFIG_SMP
  96                 seq_printf(p, "%10u ", kstat_irqs(i));
  97 #else
  98                 for_each_online_cpu(j)
  99                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 100 #endif
 101                 seq_printf(p, " %14s", irq_desc[i].chip->typename);
 102                 seq_printf(p, "  %s", action->name);
 103
 104                 for (action=action->next; action; action = action->next)
 105                         seq_printf(p, ", %s", action->name);
 106
 107                 seq_putc(p, '\n');
 108 skip:
 109                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 110         } else if (i == NR_IRQS) {
 111                 seq_printf(p, "NMI: ");
 112                 for_each_online_cpu(j)
 113                         seq_printf(p, "%10u ", nmi_count(j));
 114                 seq_putc(p, '\n');
 115                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 116         }
 117         return 0;
 118 }
 119 /* shutdown is same as "disable" */
 120 #define shutdown_xtensa_irq disable_xtensa_irq
 121
 122 static unsigned int startup_xtensa_irq(unsigned int irq)
 123 {
 124         enable_xtensa_irq(irq);
 125         return 0;               /* never anything pending */
 126 }
 127
 128 static struct hw_interrupt_type xtensa_irq_type = {
 129         "Xtensa-IRQ",
 130         startup_xtensa_irq,
 131         shutdown_xtensa_irq,
 132         enable_xtensa_irq,
 133         disable_xtensa_irq,
 134         mask_and_ack_xtensa,
 135         end_xtensa_irq
 136 };
 137
 138 static inline void mask_irq(unsigned int irq)
 139 {
 140         cached_irq_mask &= ~(1 << irq);
 141         set_sr (cached_irq_mask, INTENABLE);
 142 }
 143
 144 static inline void unmask_irq(unsigned int irq)
 145 {
 146         cached_irq_mask |= 1 << irq;
 147         set_sr (cached_irq_mask, INTENABLE);
 148 }
 149
 150 static void disable_xtensa_irq(unsigned int irq)
 151 {
 152         unsigned long flags;
 153         local_save_flags(flags);
 154         mask_irq(irq);
 155         local_irq_restore(flags);
 156 }
 157
 158 static void enable_xtensa_irq(unsigned int irq)
 159 {
 160         unsigned long flags;
 161         local_save_flags(flags);
 162         unmask_irq(irq);
 163         local_irq_restore(flags);
 164 }
 165
 166 static void mask_and_ack_xtensa(unsigned int irq)
 167 {
 168         disable_xtensa_irq(irq);
 169 }
 170
 171 static void end_xtensa_irq(unsigned int irq)
 172 {
 173         enable_xtensa_irq(irq);
 174 }
 175
 176
 177 void __init init_IRQ(void)
 178 {
 179         int i;
 180
 181         for (i=0; i < XTENSA_NR_IRQS; i++)
 182                 irq_desc[i].chip = &xtensa_irq_type;
 183
 184         cached_irq_mask = 0;
 185
 186         platform_init_irq();
 187 }