LXR linux/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
  15static struct proc_dir_entry *root_irq_dir;
  16
  17#ifdef CONFIG_SMP
  18
  19static int irq_affinity_read_proc(char *page, char **start, off_t off,
  20                                  int count, int *eof, void *data)
  21{
  22        struct irq_desc *desc = irq_desc + (long)data;
  23        cpumask_t *mask = &desc->affinity;
  24        int len;
  25
  26#ifdef CONFIG_GENERIC_PENDING_IRQ
  27        if (desc->status & IRQ_MOVE_PENDING)
  28                mask = &desc->pending_mask;
  29#endif
  30        len = cpumask_scnprintf(page, count, *mask);
  31
  32        if (count - len < 2)
  33                return -EINVAL;
  34        len += sprintf(page + len, "\n");
  35        return len;
  36}
  37
  38#ifndef is_affinity_mask_valid
  39#define is_affinity_mask_valid(val) 1
  40#endif
  41
  42int no_irq_affinity;
  43static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
  44                                   unsigned long count, void *data)
  45{
  46        unsigned int irq = (int)(long)data, full_count = count, err;
  47        cpumask_t new_value, tmp;
  48
  49        if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
  50            irq_balancing_disabled(irq))
  51                return -EIO;
  52
  53        err = cpumask_parse_user(buffer, count, new_value);
  54        if (err)
  55                return err;
  56
  57        if (!is_affinity_mask_valid(new_value))
  58                return -EINVAL;
  59
  60        /*
  61         * Do not allow disabling IRQs completely - it's a too easy
  62         * way to make the system unusable accidentally :-) At least
  63         * one online CPU still has to be targeted.
  64         */
  65        cpus_and(tmp, new_value, cpu_online_map);
  66        if (cpus_empty(tmp))
  67                /* Special case for empty set - allow the architecture
  68                   code to set default SMP affinity. */
  69                return select_smp_affinity(irq) ? -EINVAL : full_count;
  70
  71        irq_set_affinity(irq, new_value);
  72
  73        return full_count;
  74}
  75
  76#endif
  77
  78#define MAX_NAMELEN 128
  79
  80static int name_unique(unsigned int irq, struct irqaction *new_action)
  81{
  82        struct irq_desc *desc = irq_desc + irq;
  83        struct irqaction *action;
  84        unsigned long flags;
  85        int ret = 1;
  86
  87        spin_lock_irqsave(&desc->lock, flags);
  88        for (action = desc->action ; action; action = action->next) {
  89                if ((action != new_action) && action->name &&
  90                                !strcmp(new_action->name, action->name)) {
  91                        ret = 0;
  92                        break;
  93                }
  94        }
  95        spin_unlock_irqrestore(&desc->lock, flags);
  96        return ret;
  97}
  98
  99void register_handler_proc(unsigned int irq, struct irqaction *action)
 100{
 101        char name [MAX_NAMELEN];
 102
 103        if (!irq_desc[irq].dir || action->dir || !action->name ||
 104                                        !name_unique(irq, action))
 105                return;
 106
 107        memset(name, 0, MAX_NAMELEN);
 108        snprintf(name, MAX_NAMELEN, "%s", action->name);
 109
 110        /* create /proc/irq/1234/handler/ */
 111        action->dir = proc_mkdir(name, irq_desc[irq].dir);
 112}
 113
 114#undef MAX_NAMELEN
 115
 116#define MAX_NAMELEN 10
 117
 118void register_irq_proc(unsigned int irq)
 119{
 120        char name [MAX_NAMELEN];
 121
 122        if (!root_irq_dir ||
 123                (irq_desc[irq].chip == &no_irq_chip) ||
 124                        irq_desc[irq].dir)
 125                return;
 126
 127        memset(name, 0, MAX_NAMELEN);
 128        sprintf(name, "%d", irq);
 129
 130        /* create /proc/irq/1234 */
 131        irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
 132
 133#ifdef CONFIG_SMP
 134        {
 135                struct proc_dir_entry *entry;
 136
 137                /* create /proc/irq/<irq>/smp_affinity */
 138                entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
 139
 140                if (entry) {
 141                        entry->data = (void *)(long)irq;
 142                        entry->read_proc = irq_affinity_read_proc;
 143                        entry->write_proc = irq_affinity_write_proc;
 144                }
 145        }
 146#endif
 147}
 148
 149#undef MAX_NAMELEN
 150
 151void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 152{
 153        if (action->dir)
 154                remove_proc_entry(action->dir->name, irq_desc[irq].dir);
 155}
 156
 157void init_irq_proc(void)
 158{
 159        int i;
 160
 161        /* create /proc/irq */
 162        root_irq_dir = proc_mkdir("irq", NULL);
 163        if (!root_irq_dir)
 164                return;
 165
 166        /*
 167         * Create entries for all existing IRQs.
 168         */
 169        for (i = 0; i < NR_IRQS; i++)
 170                register_irq_proc(i);
 171}
 172
 173