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
  17 #include <asm/lowcore.h>
  18 #include <asm/s390_ext.h>
  19 #include <asm/irq.h>
  20
  21 /*
  22  * Simple hash strategy: index = code & 0xff;
  23  * ext_int_hash[index] is the start of the list for all external interrupts
  24  * that hash to this index. With the current set of external interrupts
  25  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
  26  * iucv and 0x2603 pfault) this is always the first element.
  27  */
  28 ext_int_info_t *ext_int_hash[256] = { 0, };
  29
  30 int register_external_interrupt(__u16 code, ext_int_handler_t handler)
  31 {
  32         ext_int_info_t *p;
  33         int index;
  34
  35         p = (ext_int_info_t *) kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
  36         if (p == NULL)
  37                 return -ENOMEM;
  38         p->code = code;
  39         p->handler = handler;
  40         index = code & 0xff;
  41         p->next = ext_int_hash[index];
  42         ext_int_hash[index] = p;
  43         return 0;
  44 }
  45
  46 int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  47                                       ext_int_info_t *p)
  48 {
  49         int index;
  50
  51         if (p == NULL)
  52                 return -EINVAL;
  53         p->code = code;
  54         p->handler = handler;
  55         index = code & 0xff;
  56         p->next = ext_int_hash[index];
  57         ext_int_hash[index] = p;
  58         return 0;
  59 }
  60
  61 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
  62 {
  63         ext_int_info_t *p, *q;
  64         int index;
  65
  66         index = code & 0xff;
  67         q = NULL;
  68         p = ext_int_hash[index];
  69         while (p != NULL) {
  70                 if (p->code == code && p->handler == handler)
  71                         break;
  72                 q = p;
  73                 p = p->next;
  74         }
  75         if (p == NULL)
  76                 return -ENOENT;
  77         if (q != NULL)
  78                 q->next = p->next;
  79         else
  80                 ext_int_hash[index] = p->next;
  81         kfree(p);
  82         return 0;
  83 }
  84
  85 int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  86                                         ext_int_info_t *p)
  87 {
  88         ext_int_info_t *q;
  89         int index;
  90
  91         if (p == NULL || p->code != code || p->handler != handler)
  92                 return -EINVAL;
  93         index = code & 0xff;
  94         q = ext_int_hash[index];
  95         if (p != q) {
  96                 while (q != NULL) {
  97                         if (q->next == p)
  98                                 break;
  99                         q = q->next;
 100                 }
 101                 if (q == NULL)
 102                         return -ENOENT;
 103                 q->next = p->next;
 104         } else
 105                 ext_int_hash[index] = p->next;
 106         return 0;
 107 }
 108
 109 void do_extint(struct pt_regs *regs, unsigned short code)
 110 {
 111         ext_int_info_t *p;
 112         int index;
 113
 114         irq_enter();
 115         asm volatile ("mc 0,0");
 116         if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 117                 /**
 118                  * Make sure that the i/o interrupt did not "overtake"
 119                  * the last HZ timer interrupt.
 120                  */
 121                 account_ticks(regs);
 122         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 123         index = code & 0xff;
 124         for (p = ext_int_hash[index]; p; p = p->next) {
 125                 if (likely(p->code == code)) {
 126                         if (likely(p->handler))
 127                                 p->handler(regs, code);
 128                 }
 129         }
 130         irq_exit();
 131 }
 132
 133 EXPORT_SYMBOL(register_external_interrupt);
 134 EXPORT_SYMBOL(unregister_external_interrupt);
 135