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