xref: /openbmc/linux/kernel/irq/proc.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * linux/kernel/irq/proc.c
3  *
4  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5  *
6  * This file contains the /proc/irq/ handling code.
7  */
8 
9 #include <linux/irq.h>
10 #include <linux/proc_fs.h>
11 #include <linux/interrupt.h>
12 
13 static struct proc_dir_entry *root_irq_dir, *irq_dir[NR_IRQS];
14 
15 #ifdef CONFIG_SMP
16 
17 /*
18  * The /proc/irq/<irq>/smp_affinity values:
19  */
20 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
21 
22 #ifdef CONFIG_GENERIC_PENDING_IRQ
23 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
24 {
25 	/*
26 	 * Save these away for later use. Re-progam when the
27 	 * interrupt is pending
28 	 */
29 	set_pending_irq(irq, mask_val);
30 }
31 #else
32 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
33 {
34 	irq_affinity[irq] = mask_val;
35 	irq_desc[irq].handler->set_affinity(irq, mask_val);
36 }
37 #endif
38 
39 static int irq_affinity_read_proc(char *page, char **start, off_t off,
40 				  int count, int *eof, void *data)
41 {
42 	int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
43 
44 	if (count - len < 2)
45 		return -EINVAL;
46 	len += sprintf(page + len, "\n");
47 	return len;
48 }
49 
50 int no_irq_affinity;
51 static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
52 				   unsigned long count, void *data)
53 {
54 	unsigned int irq = (int)(long)data, full_count = count, err;
55 	cpumask_t new_value, tmp;
56 
57 	if (!irq_desc[irq].handler->set_affinity || no_irq_affinity)
58 		return -EIO;
59 
60 	err = cpumask_parse(buffer, count, new_value);
61 	if (err)
62 		return err;
63 
64 	/*
65 	 * Do not allow disabling IRQs completely - it's a too easy
66 	 * way to make the system unusable accidentally :-) At least
67 	 * one online CPU still has to be targeted.
68 	 */
69 	cpus_and(tmp, new_value, cpu_online_map);
70 	if (cpus_empty(tmp))
71 		return -EINVAL;
72 
73 	proc_set_irq_affinity(irq, new_value);
74 
75 	return full_count;
76 }
77 
78 #endif
79 
80 #define MAX_NAMELEN 128
81 
82 static int name_unique(unsigned int irq, struct irqaction *new_action)
83 {
84 	struct irq_desc *desc = irq_desc + irq;
85 	struct irqaction *action;
86 
87 	for (action = desc->action ; action; action = action->next)
88 		if ((action != new_action) && action->name &&
89 				!strcmp(new_action->name, action->name))
90 			return 0;
91 	return 1;
92 }
93 
94 void register_handler_proc(unsigned int irq, struct irqaction *action)
95 {
96 	char name [MAX_NAMELEN];
97 
98 	if (!irq_dir[irq] || action->dir || !action->name ||
99 					!name_unique(irq, action))
100 		return;
101 
102 	memset(name, 0, MAX_NAMELEN);
103 	snprintf(name, MAX_NAMELEN, "%s", action->name);
104 
105 	/* create /proc/irq/1234/handler/ */
106 	action->dir = proc_mkdir(name, irq_dir[irq]);
107 }
108 
109 #undef MAX_NAMELEN
110 
111 #define MAX_NAMELEN 10
112 
113 void register_irq_proc(unsigned int irq)
114 {
115 	char name [MAX_NAMELEN];
116 
117 	if (!root_irq_dir ||
118 		(irq_desc[irq].handler == &no_irq_type) ||
119 			irq_dir[irq])
120 		return;
121 
122 	memset(name, 0, MAX_NAMELEN);
123 	sprintf(name, "%d", irq);
124 
125 	/* create /proc/irq/1234 */
126 	irq_dir[irq] = proc_mkdir(name, root_irq_dir);
127 
128 #ifdef CONFIG_SMP
129 	{
130 		struct proc_dir_entry *entry;
131 
132 		/* create /proc/irq/<irq>/smp_affinity */
133 		entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
134 
135 		if (entry) {
136 			entry->nlink = 1;
137 			entry->data = (void *)(long)irq;
138 			entry->read_proc = irq_affinity_read_proc;
139 			entry->write_proc = irq_affinity_write_proc;
140 		}
141 		smp_affinity_entry[irq] = entry;
142 	}
143 #endif
144 }
145 
146 #undef MAX_NAMELEN
147 
148 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
149 {
150 	if (action->dir)
151 		remove_proc_entry(action->dir->name, irq_dir[irq]);
152 }
153 
154 void init_irq_proc(void)
155 {
156 	int i;
157 
158 	/* create /proc/irq */
159 	root_irq_dir = proc_mkdir("irq", NULL);
160 	if (!root_irq_dir)
161 		return;
162 
163 	/*
164 	 * Create entries for all existing IRQs.
165 	 */
166 	for (i = 0; i < NR_IRQS; i++)
167 		register_irq_proc(i);
168 }
169 
170