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