Merge master.kernel.org:/pub/scm/linux/kernel/git/sam/kbuild
[linux-2.6] / 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