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