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