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