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