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 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 void __attribute__((weak))
  23 proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
  24 {
  25         irq_affinity[irq] = mask_val;
  26         irq_desc[irq].handler->set_affinity(irq, mask_val);
  27 }
  28
  29 static int irq_affinity_read_proc(char *page, char **start, off_t off,
  30                                   int count, int *eof, void *data)
  31 {
  32         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
  33
  34         if (count - len < 2)
  35                 return -EINVAL;
  36         len += sprintf(page + len, "\n");
  37         return len;
  38 }
  39
  40 int no_irq_affinity;
  41 static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
  42                                    unsigned long count, void *data)
  43 {
  44         unsigned int irq = (int)(long)data, full_count = count, err;
  45         cpumask_t new_value, tmp;
  46
  47         if (!irq_desc[irq].handler->set_affinity || no_irq_affinity)
  48                 return -EIO;
  49
  50         err = cpumask_parse(buffer, count, new_value);
  51         if (err)
  52                 return err;
  53
  54         /*
  55          * Do not allow disabling IRQs completely - it's a too easy
  56          * way to make the system unusable accidentally :-) At least
  57          * one online CPU still has to be targeted.
  58          */
  59         cpus_and(tmp, new_value, cpu_online_map);
  60         if (cpus_empty(tmp))
  61                 return -EINVAL;
  62
  63         proc_set_irq_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
  77         for (action = desc->action ; action; action = action->next)
  78                 if ((action != new_action) && action->name &&
  79                                 !strcmp(new_action->name, action->name))
  80                         return 0;
  81         return 1;
  82 }
  83
  84 void register_handler_proc(unsigned int irq, struct irqaction *action)
  85 {
  86         char name [MAX_NAMELEN];
  87
  88         if (!irq_dir[irq] || action->dir || !action->name ||
  89                                         !name_unique(irq, action))
  90                 return;
  91
  92         memset(name, 0, MAX_NAMELEN);
  93         snprintf(name, MAX_NAMELEN, "%s", action->name);
  94
  95         /* create /proc/irq/1234/handler/ */
  96         action->dir = proc_mkdir(name, irq_dir[irq]);
  97 }
  98
  99 #undef MAX_NAMELEN
 100
 101 #define MAX_NAMELEN 10
 102
 103 void register_irq_proc(unsigned int irq)
 104 {
 105         char name [MAX_NAMELEN];
 106
 107         if (!root_irq_dir ||
 108                 (irq_desc[irq].handler == &no_irq_type) ||
 109                         irq_dir[irq])
 110                 return;
 111
 112         memset(name, 0, MAX_NAMELEN);
 113         sprintf(name, "%d", irq);
 114
 115         /* create /proc/irq/1234 */
 116         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 117
 118 #ifdef CONFIG_SMP
 119         {
 120                 struct proc_dir_entry *entry;
 121
 122                 /* create /proc/irq/<irq>/smp_affinity */
 123                 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 124
 125                 if (entry) {
 126                         entry->nlink = 1;
 127                         entry->data = (void *)(long)irq;
 128                         entry->read_proc = irq_affinity_read_proc;
 129                         entry->write_proc = irq_affinity_write_proc;
 130                 }
 131                 smp_affinity_entry[irq] = entry;
 132         }
 133 #endif
 134 }
 135
 136 #undef MAX_NAMELEN
 137
 138 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 139 {
 140         if (action->dir)
 141                 remove_proc_entry(action->dir->name, irq_dir[irq]);
 142 }
 143
 144 void init_irq_proc(void)
 145 {
 146         int i;
 147
 148         /* create /proc/irq */
 149         root_irq_dir = proc_mkdir("irq", NULL);
 150         if (!root_irq_dir)
 151                 return;
 152
 153         /*
 154          * Create entries for all existing IRQs.
 155          */
 156         for (i = 0; i < NR_IRQS; i++)
 157                 register_irq_proc(i);
 158 }
 159