arch/s390/kernel/s390_ext.c

   1 /*
   2  *  arch/s390/kernel/s390_ext.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Holger Smolinski (Holger.Smolinski@de.ibm.com),
   7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/errno.h>
  14 #include <linux/kernel_stat.h>
  15 #include <linux/interrupt.h>
  16 #include <asm/cpu.h>
  17 #include <asm/lowcore.h>
  18 #include <asm/s390_ext.h>
  19 #include <asm/irq_regs.h>
  20 #include <asm/irq.h>
  21 #include "entry.h"
  22
  23 /*
  24  * ext_int_hash[index] is the start of the list for all external interrupts
  25  * that hash to this index. With the current set of external interrupts
  26  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
  27  * iucv and 0x2603 pfault) this is always the first element.
  28  */
  29 ext_int_info_t *ext_int_hash[256] = { NULL, };
  30
  31 static inline int ext_hash(__u16 code)
  32 {
  33         return (code + (code >> 9)) & 0xff;
  34 }
  35
  36 int register_external_interrupt(__u16 code, ext_int_handler_t handler)
  37 {
  38         ext_int_info_t *p;
  39         int index;
  40
  41         p = kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
  42         if (p == NULL)
  43                 return -ENOMEM;
  44         p->code = code;
  45         p->handler = handler;
  46         index = ext_hash(code);
  47         p->next = ext_int_hash[index];
  48         ext_int_hash[index] = p;
  49         return 0;
  50 }
  51
  52 int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  53                                       ext_int_info_t *p)
  54 {
  55         int index;
  56
  57         if (p == NULL)
  58                 return -EINVAL;
  59         p->code = code;
  60         p->handler = handler;
  61         index = ext_hash(code);
  62         p->next = ext_int_hash[index];
  63         ext_int_hash[index] = p;
  64         return 0;
  65 }
  66
  67 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
  68 {
  69         ext_int_info_t *p, *q;
  70         int index;
  71
  72         index = ext_hash(code);
  73         q = NULL;
  74         p = ext_int_hash[index];
  75         while (p != NULL) {
  76                 if (p->code == code && p->handler == handler)
  77                         break;
  78                 q = p;
  79                 p = p->next;
  80         }
  81         if (p == NULL)
  82                 return -ENOENT;
  83         if (q != NULL)
  84                 q->next = p->next;
  85         else
  86                 ext_int_hash[index] = p->next;
  87         kfree(p);
  88         return 0;
  89 }
  90
  91 int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  92                                         ext_int_info_t *p)
  93 {
  94         ext_int_info_t *q;
  95         int index;
  96
  97         if (p == NULL || p->code != code || p->handler != handler)
  98                 return -EINVAL;
  99         index = ext_hash(code);
 100         q = ext_int_hash[index];
 101         if (p != q) {
 102                 while (q != NULL) {
 103                         if (q->next == p)
 104                                 break;
 105                         q = q->next;
 106                 }
 107                 if (q == NULL)
 108                         return -ENOENT;
 109                 q->next = p->next;
 110         } else
 111                 ext_int_hash[index] = p->next;
 112         return 0;
 113 }
 114
 115 void do_extint(struct pt_regs *regs, unsigned short code)
 116 {
 117         ext_int_info_t *p;
 118         int index;
 119         struct pt_regs *old_regs;
 120
 121         old_regs = set_irq_regs(regs);
 122         s390_idle_check();
 123         irq_enter();
 124         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 125                 /* Serve timer interrupts first. */
 126                 clock_comparator_work();
 127         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 128         index = ext_hash(code);
 129         for (p = ext_int_hash[index]; p; p = p->next) {
 130                 if (likely(p->code == code))
 131                         p->handler(code);
 132         }
 133         irq_exit();
 134         set_irq_regs(old_regs);
 135 }
 136
 137 EXPORT_SYMBOL(register_external_interrupt);
 138 EXPORT_SYMBOL(unregister_external_interrupt);