c49ab8c784d27c4806885bc84e75380af10f91e5
[linux-2.6.git] / 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 = (ext_int_info_t *) 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         irq_enter();
121         old_regs = set_irq_regs(regs);
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();
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                         if (likely(p->handler))
134                                 p->handler(code);
135                 }
136         }
137         set_irq_regs(old_regs);
138         irq_exit();
139 }
140
141 EXPORT_SYMBOL(register_external_interrupt);
142 EXPORT_SYMBOL(unregister_external_interrupt);