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
ext_hash(__u16 code)31 static inline int ext_hash(__u16 code)
32 {
33 return (code + (code >> 9)) & 0xff;
34 }
35
register_external_interrupt(__u16 code,ext_int_handler_t handler)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
register_early_external_interrupt(__u16 code,ext_int_handler_t handler,ext_int_info_t * p)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
unregister_external_interrupt(__u16 code,ext_int_handler_t handler)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
unregister_early_external_interrupt(__u16 code,ext_int_handler_t handler,ext_int_info_t * p)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
do_extint(struct pt_regs * regs,unsigned short code)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 s390_idle_check();
123 irq_enter();
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);
139