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, *irq_dir[NR_IRQS];
  16
  17 #ifdef CONFIG_SMP
  18
  19 /*
  20  * The /proc/irq/<irq>/smp_affinity values:
  21  */
  22 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
  23
  24 #ifdef CONFIG_GENERIC_PENDING_IRQ
  25 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
  26 {
  27         set_balance_irq_affinity(irq, mask_val);
  28
  29         /*
  30          * Save these away for later use. Re-progam when the
  31          * interrupt is pending
  32          */
  33         set_pending_irq(irq, mask_val);
  34 }
  35 #else
  36 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
  37 {
  38         set_balance_irq_affinity(irq, mask_val);
  39         irq_affinity[irq] = mask_val;
  40         irq_desc[irq].chip->set_affinity(irq, mask_val);
  41 }
  42 #endif
  43
  44 static int irq_affinity_read_proc(char *page, char **start, off_t off,
  45                                   int count, int *eof, void *data)
  46 {
  47         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
  48
  49         if (count - len < 2)
  50                 return -EINVAL;
  51         len += sprintf(page + len, "\n");
  52         return len;
  53 }
  54
  55 int no_irq_affinity;
  56 static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
  57                                    unsigned long count, void *data)
  58 {
  59         unsigned int irq = (int)(long)data, full_count = count, err;
  60         cpumask_t new_value, tmp;
  61
  62         if (!irq_desc[irq].chip->set_affinity || no_irq_affinity)
  63                 return -EIO;
  64
  65         err = cpumask_parse(buffer, count, new_value);
  66         if (err)
  67                 return err;
  68
  69         /*
  70          * Do not allow disabling IRQs completely - it's a too easy
  71          * way to make the system unusable accidentally :-) At least
  72          * one online CPU still has to be targeted.
  73          */
  74         cpus_and(tmp, new_value, cpu_online_map);
  75         if (cpus_empty(tmp))
  76                 /* Special case for empty set - allow the architecture
  77                    code to set default SMP affinity. */
  78                 return select_smp_affinity(irq) ? -EINVAL : full_count;
  79
  80         proc_set_irq_affinity(irq, new_value);
  81
  82         return full_count;
  83 }
  84
  85 #endif
  86
  87 #define MAX_NAMELEN 128
  88
  89 static int name_unique(unsigned int irq, struct irqaction *new_action)
  90 {
  91         struct irq_desc *desc = irq_desc + irq;
  92         struct irqaction *action;
  93
  94         for (action = desc->action ; action; action = action->next)
  95                 if ((action != new_action) && action->name &&
  96                                 !strcmp(new_action->name, action->name))
  97                         return 0;
  98         return 1;
  99 }
 100
 101 void register_handler_proc(unsigned int irq, struct irqaction *action)
 102 {
 103         char name [MAX_NAMELEN];
 104
 105         if (!irq_dir[irq] || action->dir || !action->name ||
 106                                         !name_unique(irq, action))
 107                 return;
 108
 109         memset(name, 0, MAX_NAMELEN);
 110         snprintf(name, MAX_NAMELEN, "%s", action->name);
 111
 112         /* create /proc/irq/1234/handler/ */
 113         action->dir = proc_mkdir(name, irq_dir[irq]);
 114 }
 115
 116 #undef MAX_NAMELEN
 117
 118 #define MAX_NAMELEN 10
 119
 120 void register_irq_proc(unsigned int irq)
 121 {
 122         char name [MAX_NAMELEN];
 123
 124         if (!root_irq_dir ||
 125                 (irq_desc[irq].chip == &no_irq_type) ||
 126                         irq_dir[irq])
 127                 return;
 128
 129         memset(name, 0, MAX_NAMELEN);
 130         sprintf(name, "%d", irq);
 131
 132         /* create /proc/irq/1234 */
 133         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 134
 135 #ifdef CONFIG_SMP
 136         {
 137                 struct proc_dir_entry *entry;
 138
 139                 /* create /proc/irq/<irq>/smp_affinity */
 140                 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 141
 142                 if (entry) {
 143                         entry->nlink = 1;
 144                         entry->data = (void *)(long)irq;
 145                         entry->read_proc = irq_affinity_read_proc;
 146                         entry->write_proc = irq_affinity_write_proc;
 147                 }
 148                 smp_affinity_entry[irq] = entry;
 149         }
 150 #endif
 151 }
 152
 153 #undef MAX_NAMELEN
 154
 155 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 156 {
 157         if (action->dir)
 158                 remove_proc_entry(action->dir->name, irq_dir[irq]);
 159 }
 160
 161 void init_irq_proc(void)
 162 {
 163         int i;
 164
 165         /* create /proc/irq */
 166         root_irq_dir = proc_mkdir("irq", NULL);
 167         if (!root_irq_dir)
 168                 return;
 169
 170         /*
 171          * Create entries for all existing IRQs.
 172          */
 173         for (i = 0; i < NR_IRQS; i++)
 174                 register_irq_proc(i);
 175 }
 176