/*
   * linux/kernel/irq/proc.c
   *
   * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
   *
   * This file contains the /proc/irq/ handling code.
   */
  
  #include <linux/irq.h>
  #include <linux/proc_fs.h>
  #include <linux/interrupt.h>

  #include "internals.h"

  static struct proc_dir_entry *root_irq_dir, *irq_dir[NR_IRQS];
  
  #ifdef CONFIG_SMP
  
  /*
   * The /proc/irq/<irq>/smp_affinity values:
   */
  static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];

  #ifdef CONFIG_GENERIC_PENDING_IRQ
  void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
  {
  	/*
  	 * Save these away for later use. Re-progam when the
  	 * interrupt is pending
  	 */
  	set_pending_irq(irq, mask_val);
  }
  #else
  void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)

  {
  	irq_affinity[irq] = mask_val;
  	irq_desc[irq].handler->set_affinity(irq, mask_val);
  }

  #endif

  
  static int irq_affinity_read_proc(char *page, char **start, off_t off,
  				  int count, int *eof, void *data)
  {
  	int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
  
  	if (count - len < 2)
  		return -EINVAL;
  	len += sprintf(page + len, "
  ");
  	return len;
  }
  
  int no_irq_affinity;
  static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
  				   unsigned long count, void *data)
  {
  	unsigned int irq = (int)(long)data, full_count = count, err;
  	cpumask_t new_value, tmp;
  
  	if (!irq_desc[irq].handler->set_affinity || no_irq_affinity)
  		return -EIO;
  
  	err = cpumask_parse(buffer, count, new_value);
  	if (err)
  		return err;
  
  	/*
  	 * Do not allow disabling IRQs completely - it's a too easy
  	 * way to make the system unusable accidentally :-) At least
  	 * one online CPU still has to be targeted.
  	 */
  	cpus_and(tmp, new_value, cpu_online_map);
  	if (cpus_empty(tmp))

  		/* Special case for empty set - allow the architecture
  		   code to set default SMP affinity. */
  		return select_smp_affinity(irq) ? -EINVAL : full_count;

  
  	proc_set_irq_affinity(irq, new_value);
  
  	return full_count;
  }
  
  #endif
  
  #define MAX_NAMELEN 128
  
  static int name_unique(unsigned int irq, struct irqaction *new_action)
  {
  	struct irq_desc *desc = irq_desc + irq;
  	struct irqaction *action;
  
  	for (action = desc->action ; action; action = action->next)
  		if ((action != new_action) && action->name &&
  				!strcmp(new_action->name, action->name))
  			return 0;
  	return 1;
  }
  
  void register_handler_proc(unsigned int irq, struct irqaction *action)
  {
  	char name [MAX_NAMELEN];
  
  	if (!irq_dir[irq] || action->dir || !action->name ||
  					!name_unique(irq, action))
  		return;
  
  	memset(name, 0, MAX_NAMELEN);
  	snprintf(name, MAX_NAMELEN, "%s", action->name);
  
  	/* create /proc/irq/1234/handler/ */
  	action->dir = proc_mkdir(name, irq_dir[irq]);
  }
  
  #undef MAX_NAMELEN
  
  #define MAX_NAMELEN 10
  
  void register_irq_proc(unsigned int irq)
  {
  	char name [MAX_NAMELEN];
  
  	if (!root_irq_dir ||
  		(irq_desc[irq].handler == &no_irq_type) ||
  			irq_dir[irq])
  		return;
  
  	memset(name, 0, MAX_NAMELEN);
  	sprintf(name, "%d", irq);
  
  	/* create /proc/irq/1234 */
  	irq_dir[irq] = proc_mkdir(name, root_irq_dir);
  
  #ifdef CONFIG_SMP
  	{
  		struct proc_dir_entry *entry;
  
  		/* create /proc/irq/<irq>/smp_affinity */
  		entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
  
  		if (entry) {
  			entry->nlink = 1;
  			entry->data = (void *)(long)irq;
  			entry->read_proc = irq_affinity_read_proc;
  			entry->write_proc = irq_affinity_write_proc;
  		}
  		smp_affinity_entry[irq] = entry;
  	}
  #endif
  }
  
  #undef MAX_NAMELEN
  
  void unregister_handler_proc(unsigned int irq, struct irqaction *action)
  {
  	if (action->dir)
  		remove_proc_entry(action->dir->name, irq_dir[irq]);
  }
  
  void init_irq_proc(void)
  {
  	int i;
  
  	/* create /proc/irq */
  	root_irq_dir = proc_mkdir("irq", NULL);
  	if (!root_irq_dir)
  		return;
  
  	/*
  	 * Create entries for all existing IRQs.
  	 */
  	for (i = 0; i < NR_IRQS; i++)
  		register_irq_proc(i);
  }