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  * ext_int_hash[index] is the start of the list for all external interrupts
  23  * that hash to this index. With the current set of external interrupts
  24  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
  25  * iucv and 0x2603 pfault) this is always the first element.
  26  */
  27 ext_int_info_t *ext_int_hash[256] = { 0, };
  28
  29 static inline int ext_hash(__u16 code)
  30 {
  31         return (code + (code >> 9)) & 0xff;
  32 }
  33
  34 int register_external_interrupt(__u16 code, ext_int_handler_t handler)
  35 {
  36         ext_int_info_t *p;
  37         int index;
  38
  39         p = (ext_int_info_t *) kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
  40         if (p == NULL)
  41                 return -ENOMEM;
  42         p->code = code;
  43         p->handler = handler;
  44         index = ext_hash(code);
  45         p->next = ext_int_hash[index];
  46         ext_int_hash[index] = p;
  47         return 0;
  48 }
  49
  50 int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  51                                       ext_int_info_t *p)
  52 {
  53         int index;
  54
  55         if (p == NULL)
  56                 return -EINVAL;
  57         p->code = code;
  58         p->handler = handler;
  59         index = ext_hash(code);
  60         p->next = ext_int_hash[index];
  61         ext_int_hash[index] = p;
  62         return 0;
  63 }
  64
  65 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
  66 {
  67         ext_int_info_t *p, *q;
  68         int index;
  69
  70         index = ext_hash(code);
  71         q = NULL;
  72         p = ext_int_hash[index];
  73         while (p != NULL) {
  74                 if (p->code == code && p->handler == handler)
  75                         break;
  76                 q = p;
  77                 p = p->next;
  78         }
  79         if (p == NULL)
  80                 return -ENOENT;
  81         if (q != NULL)
  82                 q->next = p->next;
  83         else
  84                 ext_int_hash[index] = p->next;
  85         kfree(p);
  86         return 0;
  87 }
  88
  89 int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  90                                         ext_int_info_t *p)
  91 {
  92         ext_int_info_t *q;
  93         int index;
  94
  95         if (p == NULL || p->code != code || p->handler != handler)
  96                 return -EINVAL;
  97         index = ext_hash(code);
  98         q = ext_int_hash[index];
  99         if (p != q) {
 100                 while (q != NULL) {
 101                         if (q->next == p)
 102                                 break;
 103                         q = q->next;
 104                 }
 105                 if (q == NULL)
 106                         return -ENOENT;
 107                 q->next = p->next;
 108         } else
 109                 ext_int_hash[index] = p->next;
 110         return 0;
 111 }
 112
 113 void do_extint(struct pt_regs *regs, unsigned short code)
 114 {
 115         ext_int_info_t *p;
 116         int index;
 117
 118         irq_enter();
 119         asm volatile ("mc 0,0");
 120         if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 121                 /**
 122                  * Make sure that the i/o interrupt did not "overtake"
 123                  * the last HZ timer interrupt.
 124                  */
 125                 account_ticks(regs);
 126         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 127         index = ext_hash(code);
 128         for (p = ext_int_hash[index]; p; p = p->next) {
 129                 if (likely(p->code == code)) {
 130                         if (likely(p->handler))
 131                                 p->handler(regs, code);
 132                 }
 133         }
 134         irq_exit();
 135 }
 136
 137 EXPORT_SYMBOL(register_external_interrupt);
 138 EXPORT_SYMBOL(unregister_external_interrupt);
 139