[PATCH] Add irq flag to disable balancing for an interrupt
[linux-2.6.git] / kernel / irq / proc.c
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 #ifdef CONFIG_GENERIC_PENDING_IRQ
20 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
21 {
22         set_balance_irq_affinity(irq, mask_val);
23
24         /*
25          * Save these away for later use. Re-progam when the
26          * interrupt is pending
27          */
28         set_pending_irq(irq, mask_val);
29 }
30 #else
31 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
32 {
33         set_balance_irq_affinity(irq, mask_val);
34         irq_desc[irq].affinity = mask_val;
35         irq_desc[irq].chip->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_desc[(long)data].affinity);
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].chip->set_affinity || no_irq_affinity ||
58             irq_balancing_disabled(irq))
59                 return -EIO;
60
61         err = cpumask_parse_user(buffer, count, new_value);
62         if (err)
63                 return err;
64
65         /*
66          * Do not allow disabling IRQs completely - it's a too easy
67          * way to make the system unusable accidentally :-) At least
68          * one online CPU still has to be targeted.
69          */
70         cpus_and(tmp, new_value, cpu_online_map);
71         if (cpus_empty(tmp))
72                 /* Special case for empty set - allow the architecture
73                    code to set default SMP affinity. */
74                 return select_smp_affinity(irq) ? -EINVAL : full_count;
75
76         proc_set_irq_affinity(irq, new_value);
77
78         return full_count;
79 }
80
81 #endif
82
83 #define MAX_NAMELEN 128
84
85 static int name_unique(unsigned int irq, struct irqaction *new_action)
86 {
87         struct irq_desc *desc = irq_desc + irq;
88         struct irqaction *action;
89
90         for (action = desc->action ; action; action = action->next)
91                 if ((action != new_action) && action->name &&
92                                 !strcmp(new_action->name, action->name))
93                         return 0;
94         return 1;
95 }
96
97 void register_handler_proc(unsigned int irq, struct irqaction *action)
98 {
99         char name [MAX_NAMELEN];
100
101         if (!irq_desc[irq].dir || action->dir || !action->name ||
102                                         !name_unique(irq, action))
103                 return;
104
105         memset(name, 0, MAX_NAMELEN);
106         snprintf(name, MAX_NAMELEN, "%s", action->name);
107
108         /* create /proc/irq/1234/handler/ */
109         action->dir = proc_mkdir(name, irq_desc[irq].dir);
110 }
111
112 #undef MAX_NAMELEN
113
114 #define MAX_NAMELEN 10
115
116 void register_irq_proc(unsigned int irq)
117 {
118         char name [MAX_NAMELEN];
119
120         if (!root_irq_dir ||
121                 (irq_desc[irq].chip == &no_irq_chip) ||
122                         irq_desc[irq].dir)
123                 return;
124
125         memset(name, 0, MAX_NAMELEN);
126         sprintf(name, "%d", irq);
127
128         /* create /proc/irq/1234 */
129         irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
130
131 #ifdef CONFIG_SMP
132         {
133                 struct proc_dir_entry *entry;
134
135                 /* create /proc/irq/<irq>/smp_affinity */
136                 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
137
138                 if (entry) {
139                         entry->data = (void *)(long)irq;
140                         entry->read_proc = irq_affinity_read_proc;
141                         entry->write_proc = irq_affinity_write_proc;
142                 }
143         }
144 #endif
145 }
146
147 #undef MAX_NAMELEN
148
149 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
150 {
151         if (action->dir)
152                 remove_proc_entry(action->dir->name, irq_desc[irq].dir);
153 }
154
155 void init_irq_proc(void)
156 {
157         int i;
158
159         /* create /proc/irq */
160         root_irq_dir = proc_mkdir("irq", NULL);
161         if (!root_irq_dir)
162                 return;
163
164         /*
165          * Create entries for all existing IRQs.
166          */
167         for (i = 0; i < NR_IRQS; i++)
168                 register_irq_proc(i);
169 }
170