xref: /openbmc/linux/kernel/irq/proc.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 #include "internals.h"
14 
15 static struct proc_dir_entry *root_irq_dir;
16 
17 #ifdef CONFIG_SMP
18 
19 static int irq_affinity_read_proc(char *page, char **start, off_t off,
20 				  int count, int *eof, void *data)
21 {
22 	int len = cpumask_scnprintf(page, count, irq_desc[(long)data].affinity);
23 
24 	if (count - len < 2)
25 		return -EINVAL;
26 	len += sprintf(page + len, "\n");
27 	return len;
28 }
29 
30 #ifndef is_affinity_mask_valid
31 #define is_affinity_mask_valid(val) 1
32 #endif
33 
34 int no_irq_affinity;
35 static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
36 				   unsigned long count, void *data)
37 {
38 	unsigned int irq = (int)(long)data, full_count = count, err;
39 	cpumask_t new_value, tmp;
40 
41 	if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
42 	    irq_balancing_disabled(irq))
43 		return -EIO;
44 
45 	err = cpumask_parse_user(buffer, count, new_value);
46 	if (err)
47 		return err;
48 
49 	if (!is_affinity_mask_valid(new_value))
50 		return -EINVAL;
51 
52 	/*
53 	 * Do not allow disabling IRQs completely - it's a too easy
54 	 * way to make the system unusable accidentally :-) At least
55 	 * one online CPU still has to be targeted.
56 	 */
57 	cpus_and(tmp, new_value, cpu_online_map);
58 	if (cpus_empty(tmp))
59 		/* Special case for empty set - allow the architecture
60 		   code to set default SMP affinity. */
61 		return select_smp_affinity(irq) ? -EINVAL : full_count;
62 
63 	irq_set_affinity(irq, new_value);
64 
65 	return full_count;
66 }
67 
68 #endif
69 
70 #define MAX_NAMELEN 128
71 
72 static int name_unique(unsigned int irq, struct irqaction *new_action)
73 {
74 	struct irq_desc *desc = irq_desc + irq;
75 	struct irqaction *action;
76 	unsigned long flags;
77 	int ret = 1;
78 
79 	spin_lock_irqsave(&desc->lock, flags);
80 	for (action = desc->action ; action; action = action->next) {
81 		if ((action != new_action) && action->name &&
82 				!strcmp(new_action->name, action->name)) {
83 			ret = 0;
84 			break;
85 		}
86 	}
87 	spin_unlock_irqrestore(&desc->lock, flags);
88 	return ret;
89 }
90 
91 void register_handler_proc(unsigned int irq, struct irqaction *action)
92 {
93 	char name [MAX_NAMELEN];
94 
95 	if (!irq_desc[irq].dir || action->dir || !action->name ||
96 					!name_unique(irq, action))
97 		return;
98 
99 	memset(name, 0, MAX_NAMELEN);
100 	snprintf(name, MAX_NAMELEN, "%s", action->name);
101 
102 	/* create /proc/irq/1234/handler/ */
103 	action->dir = proc_mkdir(name, irq_desc[irq].dir);
104 }
105 
106 #undef MAX_NAMELEN
107 
108 #define MAX_NAMELEN 10
109 
110 void register_irq_proc(unsigned int irq)
111 {
112 	char name [MAX_NAMELEN];
113 
114 	if (!root_irq_dir ||
115 		(irq_desc[irq].chip == &no_irq_chip) ||
116 			irq_desc[irq].dir)
117 		return;
118 
119 	memset(name, 0, MAX_NAMELEN);
120 	sprintf(name, "%d", irq);
121 
122 	/* create /proc/irq/1234 */
123 	irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
124 
125 #ifdef CONFIG_SMP
126 	{
127 		struct proc_dir_entry *entry;
128 
129 		/* create /proc/irq/<irq>/smp_affinity */
130 		entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
131 
132 		if (entry) {
133 			entry->data = (void *)(long)irq;
134 			entry->read_proc = irq_affinity_read_proc;
135 			entry->write_proc = irq_affinity_write_proc;
136 		}
137 	}
138 #endif
139 }
140 
141 #undef MAX_NAMELEN
142 
143 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
144 {
145 	if (action->dir)
146 		remove_proc_entry(action->dir->name, irq_desc[irq].dir);
147 }
148 
149 void init_irq_proc(void)
150 {
151 	int i;
152 
153 	/* create /proc/irq */
154 	root_irq_dir = proc_mkdir("irq", NULL);
155 	if (!root_irq_dir)
156 		return;
157 
158 	/*
159 	 * Create entries for all existing IRQs.
160 	 */
161 	for (i = 0; i < NR_IRQS; i++)
162 		register_irq_proc(i);
163 }
164 
165