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-rw-r--r--arch/m68k/hp300/ints.c175
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diff --git a/arch/m68k/hp300/ints.c b/arch/m68k/hp300/ints.c
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1/*
2 * linux/arch/m68k/hp300/ints.c
3 *
4 * Copyright (C) 1998 Philip Blundell <philb@gnu.org>
5 *
6 * This file contains the HP300-specific interrupt handling.
7 * We only use the autovector interrupts, and therefore we need to
8 * maintain lists of devices sharing each ipl.
9 * [ipl list code added by Peter Maydell <pmaydell@chiark.greenend.org.uk> 06/1998]
10 */
11
12#include <linux/kernel.h>
13#include <linux/types.h>
14#include <linux/init.h>
15#include <linux/sched.h>
16#include <linux/kernel_stat.h>
17#include <linux/interrupt.h>
18#include <linux/spinlock.h>
19#include <asm/machdep.h>
20#include <asm/irq.h>
21#include <asm/io.h>
22#include <asm/system.h>
23#include <asm/traps.h>
24#include <asm/ptrace.h>
25#include <asm/errno.h>
26#include "ints.h"
27
28/* Each ipl has a linked list of interrupt service routines.
29 * Service routines are added via hp300_request_irq() and removed
30 * via hp300_free_irq(). The device driver should set IRQ_FLG_FAST
31 * if it needs to be serviced early (eg FIFOless UARTs); this will
32 * cause it to be added at the front of the queue rather than
33 * the back.
34 * Currently IRQ_FLG_SLOW and flags=0 are treated identically; if
35 * we needed three levels of priority we could distinguish them
36 * but this strikes me as mildly ugly...
37 */
38
39/* we start with no entries in any list */
40static irq_node_t *hp300_irq_list[HP300_NUM_IRQS];
41
42static spinlock_t irqlist_lock;
43
44/* This handler receives all interrupts, dispatching them to the registered handlers */
45static irqreturn_t hp300_int_handler(int irq, void *dev_id, struct pt_regs *fp)
46{
47 irq_node_t *t;
48 /* We just give every handler on the chain an opportunity to handle
49 * the interrupt, in priority order.
50 */
51 for(t = hp300_irq_list[irq]; t; t=t->next)
52 t->handler(irq, t->dev_id, fp);
53 /* We could put in some accounting routines, checks for stray interrupts,
54 * etc, in here. Note that currently we can't tell whether or not
55 * a handler handles the interrupt, though.
56 */
57 return IRQ_HANDLED;
58}
59
60static irqreturn_t hp300_badint(int irq, void *dev_id, struct pt_regs *fp)
61{
62 num_spurious += 1;
63 return IRQ_NONE;
64}
65
66irqreturn_t (*hp300_default_handler[SYS_IRQS])(int, void *, struct pt_regs *) = {
67 [0] = hp300_badint,
68 [1] = hp300_int_handler,
69 [2] = hp300_int_handler,
70 [3] = hp300_int_handler,
71 [4] = hp300_int_handler,
72 [5] = hp300_int_handler,
73 [6] = hp300_int_handler,
74 [7] = hp300_int_handler
75};
76
77/* dev_id had better be unique to each handler because it's the only way we have
78 * to distinguish handlers when removing them...
79 *
80 * It would be pretty easy to support IRQ_FLG_LOCK (handler is not replacable)
81 * and IRQ_FLG_REPLACE (handler replaces existing one with this dev_id)
82 * if we wanted to. IRQ_FLG_FAST is needed for devices where interrupt latency
83 * matters (eg the dreaded FIFOless UART...)
84 */
85int hp300_request_irq(unsigned int irq,
86 irqreturn_t (*handler) (int, void *, struct pt_regs *),
87 unsigned long flags, const char *devname, void *dev_id)
88{
89 irq_node_t *t, *n = new_irq_node();
90
91 if (!n) /* oops, no free nodes */
92 return -ENOMEM;
93
94 spin_lock_irqsave(&irqlist_lock, flags);
95
96 if (!hp300_irq_list[irq]) {
97 /* no list yet */
98 hp300_irq_list[irq] = n;
99 n->next = NULL;
100 } else if (flags & IRQ_FLG_FAST) {
101 /* insert at head of list */
102 n->next = hp300_irq_list[irq];
103 hp300_irq_list[irq] = n;
104 } else {
105 /* insert at end of list */
106 for(t = hp300_irq_list[irq]; t->next; t = t->next)
107 /* do nothing */;
108 n->next = NULL;
109 t->next = n;
110 }
111
112 /* Fill in n appropriately */
113 n->handler = handler;
114 n->flags = flags;
115 n->dev_id = dev_id;
116 n->devname = devname;
117 spin_unlock_irqrestore(&irqlist_lock, flags);
118 return 0;
119}
120
121void hp300_free_irq(unsigned int irq, void *dev_id)
122{
123 irq_node_t *t;
124 unsigned long flags;
125
126 spin_lock_irqsave(&irqlist_lock, flags);
127
128 t = hp300_irq_list[irq];
129 if (!t) /* no handlers at all for that IRQ */
130 {
131 printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq);
132 spin_unlock_irqrestore(&irqlist_lock, flags);
133 return;
134 }
135
136 if (t->dev_id == dev_id)
137 { /* removing first handler on chain */
138 t->flags = IRQ_FLG_STD; /* we probably don't really need these */
139 t->dev_id = NULL;
140 t->devname = NULL;
141 t->handler = NULL; /* frees this irq_node_t */
142 hp300_irq_list[irq] = t->next;
143 spin_unlock_irqrestore(&irqlist_lock, flags);
144 return;
145 }
146
147 /* OK, must be removing from middle of the chain */
148
149 for (t = hp300_irq_list[irq]; t->next && t->next->dev_id != dev_id; t = t->next)
150 /* do nothing */;
151 if (!t->next)
152 {
153 printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq);
154 spin_unlock_irqrestore(&irqlist_lock, flags);
155 return;
156 }
157 /* remove the entry after t: */
158 t->next->flags = IRQ_FLG_STD;
159 t->next->dev_id = NULL;
160 t->next->devname = NULL;
161 t->next->handler = NULL;
162 t->next = t->next->next;
163
164 spin_unlock_irqrestore(&irqlist_lock, flags);
165}
166
167int show_hp300_interrupts(struct seq_file *p, void *v)
168{
169 return 0;
170}
171
172void __init hp300_init_IRQ(void)
173{
174 spin_lock_init(&irqlist_lock);
175}