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