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
  67         __do_IRQ(irq, regs);
  68
  69         irq_exit();
  70
  71         return 1;
  72 }
  73
  74 /*
  75  * Generic, controller-independent functions:
  76  */
  77
  78 int show_interrupts(struct seq_file *p, void *v)
  79 {
  80         int i = *(loff_t *) v, j;
  81         struct irqaction * action;
  82         unsigned long flags;
  83
  84         if (i == 0) {
  85                 seq_printf(p, "           ");
  86                 for (j=0; j<NR_CPUS; j++)
  87                         if (cpu_online(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 (j = 0; j < NR_CPUS; j++)
 102                         if (cpu_online(j))
 103                                 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 104 #endif
 105                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
 106                 seq_printf(p, "  %s", action->name);
 107
 108                 for (action=action->next; action; action = action->next)
 109                         seq_printf(p, ", %s", action->name);
 110
 111                 seq_putc(p, '\n');
 112 skip:
 113                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 114         } else if (i == NR_IRQS) {
 115                 seq_printf(p, "NMI: ");
 116                 for (j = 0; j < NR_CPUS; j++)
 117                         if (cpu_online(j))
 118                                 seq_printf(p, "%10u ", nmi_count(j));
 119                 seq_putc(p, '\n');
 120                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 121         }
 122         return 0;
 123 }
 124 /* shutdown is same as "disable" */
 125 #define shutdown_xtensa_irq disable_xtensa_irq
 126
 127 static unsigned int startup_xtensa_irq(unsigned int irq)
 128 {
 129         enable_xtensa_irq(irq);
 130         return 0;               /* never anything pending */
 131 }
 132
 133 static struct hw_interrupt_type xtensa_irq_type = {
 134         "Xtensa-IRQ",
 135         startup_xtensa_irq,
 136         shutdown_xtensa_irq,
 137         enable_xtensa_irq,
 138         disable_xtensa_irq,
 139         mask_and_ack_xtensa,
 140         end_xtensa_irq
 141 };
 142
 143 static inline void mask_irq(unsigned int irq)
 144 {
 145         cached_irq_mask &= ~(1 << irq);
 146         set_sr (cached_irq_mask, INTENABLE);
 147 }
 148
 149 static inline void unmask_irq(unsigned int irq)
 150 {
 151         cached_irq_mask |= 1 << irq;
 152         set_sr (cached_irq_mask, INTENABLE);
 153 }
 154
 155 static void disable_xtensa_irq(unsigned int irq)
 156 {
 157         unsigned long flags;
 158         local_save_flags(flags);
 159         mask_irq(irq);
 160         local_irq_restore(flags);
 161 }
 162
 163 static void enable_xtensa_irq(unsigned int irq)
 164 {
 165         unsigned long flags;
 166         local_save_flags(flags);
 167         unmask_irq(irq);
 168         local_irq_restore(flags);
 169 }
 170
 171 static void mask_and_ack_xtensa(unsigned int irq)
 172 {
 173         disable_xtensa_irq(irq);
 174 }
 175
 176 static void end_xtensa_irq(unsigned int irq)
 177 {
 178         enable_xtensa_irq(irq);
 179 }
 180
 181
 182 void __init init_IRQ(void)
 183 {
 184         int i;
 185
 186         for (i=0; i < XTENSA_NR_IRQS; i++)
 187                 irq_desc[i].handler = &xtensa_irq_type;
 188
 189         cached_irq_mask = 0;
 190
 191         platform_init_irq();
 192 }