summaryrefslogtreecommitdiffstats
path: root/arch/m68k/hp300/ints.c
blob: 0c5bb403e893e68ad54486c90a2ff15179b74101 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/*
 *  linux/arch/m68k/hp300/ints.c
 *
 *  Copyright (C) 1998 Philip Blundell <philb@gnu.org>
 *
 *  This file contains the HP300-specific interrupt handling.
 *  We only use the autovector interrupts, and therefore we need to
 *  maintain lists of devices sharing each ipl.
 *  [ipl list code added by Peter Maydell <pmaydell@chiark.greenend.org.uk> 06/1998]
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/ptrace.h>
#include <asm/errno.h>
#include "ints.h"

/* Each ipl has a linked list of interrupt service routines.
 * Service routines are added via hp300_request_irq() and removed
 * via hp300_free_irq(). The device driver should set IRQ_FLG_FAST
 * if it needs to be serviced early (eg FIFOless UARTs); this will
 * cause it to be added at the front of the queue rather than
 * the back.
 * Currently IRQ_FLG_SLOW and flags=0 are treated identically; if
 * we needed three levels of priority we could distinguish them
 * but this strikes me as mildly ugly...
 */

/* we start with no entries in any list */
static irq_node_t *hp300_irq_list[HP300_NUM_IRQS];

static spinlock_t irqlist_lock;

/* This handler receives all interrupts, dispatching them to the registered handlers */
static irqreturn_t hp300_int_handler(int irq, void *dev_id, struct pt_regs *fp)
{
        irq_node_t *t;
        /* We just give every handler on the chain an opportunity to handle
         * the interrupt, in priority order.
         */
        for(t = hp300_irq_list[irq]; t; t=t->next)
                t->handler(irq, t->dev_id, fp);
        /* We could put in some accounting routines, checks for stray interrupts,
         * etc, in here. Note that currently we can't tell whether or not
         * a handler handles the interrupt, though.
         */
	return IRQ_HANDLED;
}

static irqreturn_t hp300_badint(int irq, void *dev_id, struct pt_regs *fp)
{
	num_spurious += 1;
	return IRQ_NONE;
}

irqreturn_t (*hp300_default_handler[SYS_IRQS])(int, void *, struct pt_regs *) = {
	[0] = hp300_badint,
	[1] = hp300_int_handler,
	[2] = hp300_int_handler,
	[3] = hp300_int_handler,
	[4] = hp300_int_handler,
	[5] = hp300_int_handler,
	[6] = hp300_int_handler,
	[7] = hp300_int_handler
};

/* dev_id had better be unique to each handler because it's the only way we have
 * to distinguish handlers when removing them...
 *
 * It would be pretty easy to support IRQ_FLG_LOCK (handler is not replacable)
 * and IRQ_FLG_REPLACE (handler replaces existing one with this dev_id)
 * if we wanted to. IRQ_FLG_FAST is needed for devices where interrupt latency
 * matters (eg the dreaded FIFOless UART...)
 */
int hp300_request_irq(unsigned int irq,
                      irqreturn_t (*handler) (int, void *, struct pt_regs *),
                      unsigned long flags, const char *devname, void *dev_id)
{
        irq_node_t *t, *n = new_irq_node();

        if (!n)                                   /* oops, no free nodes */
                return -ENOMEM;

	spin_lock_irqsave(&irqlist_lock, flags);

        if (!hp300_irq_list[irq]) {
                /* no list yet */
                hp300_irq_list[irq] = n;
                n->next = NULL;
        } else if (flags & IRQ_FLG_FAST) {
                /* insert at head of list */
                n->next = hp300_irq_list[irq];
                hp300_irq_list[irq] = n;
        } else {
                /* insert at end of list */
                for(t = hp300_irq_list[irq]; t->next; t = t->next)
                        /* do nothing */;
                n->next = NULL;
                t->next = n;
        }

        /* Fill in n appropriately */
        n->handler = handler;
        n->flags = flags;
        n->dev_id = dev_id;
        n->devname = devname;
	spin_unlock_irqrestore(&irqlist_lock, flags);
	return 0;
}

void hp300_free_irq(unsigned int irq, void *dev_id)
{
        irq_node_t *t;
        unsigned long flags;

        spin_lock_irqsave(&irqlist_lock, flags);

        t = hp300_irq_list[irq];
        if (!t)                                   /* no handlers at all for that IRQ */
        {
                printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq);
                spin_unlock_irqrestore(&irqlist_lock, flags);
		return;
        }

        if (t->dev_id == dev_id)
        {                                         /* removing first handler on chain */
                t->flags = IRQ_FLG_STD;           /* we probably don't really need these */
                t->dev_id = NULL;
                t->devname = NULL;
                t->handler = NULL;                /* frees this irq_node_t */
                hp300_irq_list[irq] = t->next;
		spin_unlock_irqrestore(&irqlist_lock, flags);
		return;
        }

        /* OK, must be removing from middle of the chain */

        for (t = hp300_irq_list[irq]; t->next && t->next->dev_id != dev_id; t = t->next)
                /* do nothing */;
        if (!t->next)
        {
                printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq);
		spin_unlock_irqrestore(&irqlist_lock, flags);
		return;
        }
        /* remove the entry after t: */
        t->next->flags = IRQ_FLG_STD;
        t->next->dev_id = NULL;
	t->next->devname = NULL;
	t->next->handler = NULL;
        t->next = t->next->next;

	spin_unlock_irqrestore(&irqlist_lock, flags);
}

int show_hp300_interrupts(struct seq_file *p, void *v)
{
	return 0;
}

void __init hp300_init_IRQ(void)
{
	spin_lock_init(&irqlist_lock);
}
OpenPOWER on IntegriCloud