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_regs.h>
  20 #include <asm/irq.h>
  21
  22 /*
  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] = { NULL, };
  29
  30 static inline int ext_hash(__u16 code)
  31 {
  32         return (code + (code >> 9)) & 0xff;
  33 }
  34
  35 int register_external_interrupt(__u16 code, ext_int_handler_t handler)
  36 {
  37         ext_int_info_t *p;
  38         int index;
  39
  40         p = kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
  41         if (p == NULL)
  42                 return -ENOMEM;
  43         p->code = code;
  44         p->handler = handler;
  45         index = ext_hash(code);
  46         p->next = ext_int_hash[index];
  47         ext_int_hash[index] = p;
  48         return 0;
  49 }
  50
  51 int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  52                                       ext_int_info_t *p)
  53 {
  54         int index;
  55
  56         if (p == NULL)
  57                 return -EINVAL;
  58         p->code = code;
  59         p->handler = handler;
  60         index = ext_hash(code);
  61         p->next = ext_int_hash[index];
  62         ext_int_hash[index] = p;
  63         return 0;
  64 }
  65
  66 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
  67 {
  68         ext_int_info_t *p, *q;
  69         int index;
  70
  71         index = ext_hash(code);
  72         q = NULL;
  73         p = ext_int_hash[index];
  74         while (p != NULL) {
  75                 if (p->code == code && p->handler == handler)
  76                         break;
  77                 q = p;
  78                 p = p->next;
  79         }
  80         if (p == NULL)
  81                 return -ENOENT;
  82         if (q != NULL)
  83                 q->next = p->next;
  84         else
  85                 ext_int_hash[index] = p->next;
  86         kfree(p);
  87         return 0;
  88 }
  89
  90 int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  91                                         ext_int_info_t *p)
  92 {
  93         ext_int_info_t *q;
  94         int index;
  95
  96         if (p == NULL || p->code != code || p->handler != handler)
  97                 return -EINVAL;
  98         index = ext_hash(code);
  99         q = ext_int_hash[index];
 100         if (p != q) {
 101                 while (q != NULL) {
 102                         if (q->next == p)
 103                                 break;
 104                         q = q->next;
 105                 }
 106                 if (q == NULL)
 107                         return -ENOENT;
 108                 q->next = p->next;
 109         } else
 110                 ext_int_hash[index] = p->next;
 111         return 0;
 112 }
 113
 114 void do_extint(struct pt_regs *regs, unsigned short code)
 115 {
 116         ext_int_info_t *p;
 117         int index;
 118         struct pt_regs *old_regs;
 119
 120         old_regs = set_irq_regs(regs);
 121         irq_enter();
 122         asm volatile ("mc 0,0");
 123         if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 124                 /**
 125                  * Make sure that the i/o interrupt did not "overtake"
 126                  * the last HZ timer interrupt.
 127                  */
 128                 account_ticks(S390_lowcore.int_clock);
 129         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 130         index = ext_hash(code);
 131         for (p = ext_int_hash[index]; p; p = p->next) {
 132                 if (likely(p->code == code))
 133                         p->handler(code);
 134         }
 135         irq_exit();
 136         set_irq_regs(old_regs);
 137 }
 138
 139 EXPORT_SYMBOL(register_external_interrupt);
 140 EXPORT_SYMBOL(unregister_external_interrupt);