aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/irq/proc.c
blob: 85d08daa6600ee826e1810010500ddca76133e86 (plain) (blame)
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
/*
 * linux/kernel/irq/proc.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains the /proc/irq/ handling code.
 */

#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/interrupt.h>

static struct proc_dir_entry *root_irq_dir, *irq_dir[NR_IRQS];

#ifdef CONFIG_SMP

/*
 * The /proc/irq/<irq>/smp_affinity values:
 */
static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];

void __attribute__((weak))
proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
{
	irq_affinity[irq] = mask_val;
	irq_desc[irq].handler->set_affinity(irq, mask_val);
}

static int irq_affinity_read_proc(char *page, char **start, off_t off,
				  int count, int *eof, void *data)
{
	int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);

	if (count - len < 2)
		return -EINVAL;
	len += sprintf(page + len, "\n");
	return len;
}

int no_irq_affinity;
static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
				   unsigned long count, void *data)
{
	unsigned int irq = (int)(long)data, full_count = count, err;
	cpumask_t new_value, tmp;

	if (!irq_desc[irq].handler->set_affinity || no_irq_affinity)
		return -EIO;

	err = cpumask_parse(buffer, count, new_value);
	if (err)
		return err;

	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	cpus_and(tmp, new_value, cpu_online_map);
	if (cpus_empty(tmp))
		return -EINVAL;

	proc_set_irq_affinity(irq, new_value);

	return full_count;
}

#endif

#define MAX_NAMELEN 128

static int name_unique(unsigned int irq, struct irqaction *new_action)
{
	struct irq_desc *desc = irq_desc + irq;
	struct irqaction *action;

	for (action = desc->action ; action; action = action->next)
		if ((action != new_action) && action->name &&
				!strcmp(new_action->name, action->name))
			return 0;
	return 1;
}

void register_handler_proc(unsigned int irq, struct irqaction *action)
{
	char name [MAX_NAMELEN];

	if (!irq_dir[irq] || action->dir || !action->name ||
					!name_unique(irq, action))
		return;

	memset(name, 0, MAX_NAMELEN);
	snprintf(name, MAX_NAMELEN, "%s", action->name);

	/* create /proc/irq/1234/handler/ */
	action->dir = proc_mkdir(name, irq_dir[irq]);
}

#undef MAX_NAMELEN

#define MAX_NAMELEN 10

void register_irq_proc(unsigned int irq)
{
	char name [MAX_NAMELEN];

	if (!root_irq_dir ||
		(irq_desc[irq].handler == &no_irq_type) ||
			irq_dir[irq])
		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
	irq_dir[irq] = proc_mkdir(name, root_irq_dir);

#ifdef CONFIG_SMP
	{
		struct proc_dir_entry *entry;

		/* create /proc/irq/<irq>/smp_affinity */
		entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);

		if (entry) {
			entry->nlink = 1;
			entry->data = (void *)(long)irq;
			entry->read_proc = irq_affinity_read_proc;
			entry->write_proc = irq_affinity_write_proc;
		}
		smp_affinity_entry[irq] = entry;
	}
#endif
}

#undef MAX_NAMELEN

void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
	if (action->dir)
		remove_proc_entry(action->dir->name, irq_dir[irq]);
}

void init_irq_proc(void)
{
	int i;

	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", NULL);
	if (!root_irq_dir)
		return;

	/*
	 * Create entries for all existing IRQs.
	 */
	for (i = 0; i < NR_IRQS; i++)
		register_irq_proc(i);
}