/**
   * A generic FSM based on fsm used in isdn4linux
   *
   */
  
  #include "fsm.h"
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/timer.h>
  
  MODULE_AUTHOR("(C) 2000 IBM Corp. by Fritz Elfert (felfert@millenux.com)");
  MODULE_DESCRIPTION("Finite state machine helper functions");
  MODULE_LICENSE("GPL");
  
  fsm_instance *
  init_fsm(char *name, const char **state_names, const char **event_names, int nr_states,
  		int nr_events, const fsm_node *tmpl, int tmpl_len, gfp_t order)
  {
  	int i;
  	fsm_instance *this;
  	fsm_function_t *m;
  	fsm *f;
  
  	this = kzalloc(sizeof(fsm_instance), order);
  	if (this == NULL) {
  		printk(KERN_WARNING
  			"fsm(%s): init_fsm: Couldn't alloc instance
  ", name);
  		return NULL;
  	}
  	strlcpy(this->name, name, sizeof(this->name));
  	init_waitqueue_head(&this->wait_q);
  
  	f = kzalloc(sizeof(fsm), order);
  	if (f == NULL) {
  		printk(KERN_WARNING
  			"fsm(%s): init_fsm: Couldn't alloc fsm
  ", name);
  		kfree_fsm(this);
  		return NULL;
  	}
  	f->nr_events = nr_events;
  	f->nr_states = nr_states;
  	f->event_names = event_names;
  	f->state_names = state_names;
  	this->f = f;
  
  	m = kcalloc(nr_states*nr_events, sizeof(fsm_function_t), order);
  	if (m == NULL) {
  		printk(KERN_WARNING
  			"fsm(%s): init_fsm: Couldn't alloc jumptable
  ", name);
  		kfree_fsm(this);
  		return NULL;
  	}
  	f->jumpmatrix = m;
  
  	for (i = 0; i < tmpl_len; i++) {
  		if ((tmpl[i].cond_state >= nr_states) ||
  		    (tmpl[i].cond_event >= nr_events)   ) {
  			printk(KERN_ERR
  				"fsm(%s): init_fsm: Bad template l=%d st(%ld/%ld) ev(%ld/%ld)
  ",
  				name, i, (long)tmpl[i].cond_state, (long)f->nr_states,
  				(long)tmpl[i].cond_event, (long)f->nr_events);
  			kfree_fsm(this);
  			return NULL;
  		} else
  			m[nr_states * tmpl[i].cond_event + tmpl[i].cond_state] =
  				tmpl[i].function;
  	}
  	return this;
  }
  
  void
  kfree_fsm(fsm_instance *this)
  {
  	if (this) {
  		if (this->f) {
  			kfree(this->f->jumpmatrix);
  			kfree(this->f);
  		}
  		kfree(this);
  	} else
  		printk(KERN_WARNING
  			"fsm: kfree_fsm called with NULL argument
  ");
  }
  
  #if FSM_DEBUG_HISTORY
  void
  fsm_print_history(fsm_instance *fi)
  {
  	int idx = 0;
  	int i;
  
  	if (fi->history_size >= FSM_HISTORY_SIZE)
  		idx = fi->history_index;
  
  	printk(KERN_DEBUG "fsm(%s): History:
  ", fi->name);
  	for (i = 0; i < fi->history_size; i++) {
  		int e = fi->history[idx].event;
  		int s = fi->history[idx++].state;
  		idx %= FSM_HISTORY_SIZE;
  		if (e == -1)
  			printk(KERN_DEBUG "  S=%s
  ",
  			       fi->f->state_names[s]);
  		else
  			printk(KERN_DEBUG "  S=%s E=%s
  ",
  			       fi->f->state_names[s],
  			       fi->f->event_names[e]);
  	}
  	fi->history_size = fi->history_index = 0;
  }
  
  void
  fsm_record_history(fsm_instance *fi, int state, int event)
  {
  	fi->history[fi->history_index].state = state;
  	fi->history[fi->history_index++].event = event;
  	fi->history_index %= FSM_HISTORY_SIZE;
  	if (fi->history_size < FSM_HISTORY_SIZE)
  		fi->history_size++;
  }
  #endif
  
  const char *
  fsm_getstate_str(fsm_instance *fi)
  {
  	int st = atomic_read(&fi->state);
  	if (st >= fi->f->nr_states)
  		return "Invalid";
  	return fi->f->state_names[st];
  }
  
  static void
  fsm_expire_timer(fsm_timer *this)
  {
  #if FSM_TIMER_DEBUG
  	printk(KERN_DEBUG "fsm(%s): Timer %p expired
  ",
  	       this->fi->name, this);
  #endif
  	fsm_event(this->fi, this->expire_event, this->event_arg);
  }
  
  void
  fsm_settimer(fsm_instance *fi, fsm_timer *this)
  {
  	this->fi = fi;
  	this->tl.function = (void *)fsm_expire_timer;
  	this->tl.data = (long)this;
  #if FSM_TIMER_DEBUG
  	printk(KERN_DEBUG "fsm(%s): Create timer %p
  ", fi->name,
  	       this);
  #endif
  	init_timer(&this->tl);
  }
  
  void
  fsm_deltimer(fsm_timer *this)
  {
  #if FSM_TIMER_DEBUG
  	printk(KERN_DEBUG "fsm(%s): Delete timer %p
  ", this->fi->name,
  		this);
  #endif
  	del_timer(&this->tl);
  }
  
  int
  fsm_addtimer(fsm_timer *this, int millisec, int event, void *arg)
  {
  
  #if FSM_TIMER_DEBUG
  	printk(KERN_DEBUG "fsm(%s): Add timer %p %dms
  ",
  	       this->fi->name, this, millisec);
  #endif
  
  	init_timer(&this->tl);
  	this->tl.function = (void *)fsm_expire_timer;
  	this->tl.data = (long)this;
  	this->expire_event = event;
  	this->event_arg = arg;
  	this->tl.expires = jiffies + (millisec * HZ) / 1000;
  	add_timer(&this->tl);
  	return 0;
  }
  
  /* FIXME: this function is never used, why */
  void
  fsm_modtimer(fsm_timer *this, int millisec, int event, void *arg)
  {
  
  #if FSM_TIMER_DEBUG
  	printk(KERN_DEBUG "fsm(%s): Restart timer %p %dms
  ",
  		this->fi->name, this, millisec);
  #endif
  
  	del_timer(&this->tl);
  	init_timer(&this->tl);
  	this->tl.function = (void *)fsm_expire_timer;
  	this->tl.data = (long)this;
  	this->expire_event = event;
  	this->event_arg = arg;
  	this->tl.expires = jiffies + (millisec * HZ) / 1000;
  	add_timer(&this->tl);
  }
  
  EXPORT_SYMBOL(init_fsm);
  EXPORT_SYMBOL(kfree_fsm);
  EXPORT_SYMBOL(fsm_settimer);
  EXPORT_SYMBOL(fsm_deltimer);
  EXPORT_SYMBOL(fsm_addtimer);
  EXPORT_SYMBOL(fsm_modtimer);
  EXPORT_SYMBOL(fsm_getstate_str);
  
  #if FSM_DEBUG_HISTORY
  EXPORT_SYMBOL(fsm_print_history);
  EXPORT_SYMBOL(fsm_record_history);
  #endif