Quelle  fsm.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * A generic FSM based on fsm used in isdn4linux
 *
 */

#include "fsm.h"
#include <linux/export.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/timer.h>

MODULE_AUTHOR("(C) 2000 IBM Corp. by Fritz Elfert ");
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\n", name);
  return NULL;
 }
 strscpy(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\n", 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\n", 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)\n",
    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\n");
}

#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:\n", 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\n",
          fi->f->state_names[s]);
  else
   printk(KERN_DEBUG " S=%s E=%s\n",
          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(struct timer_list *t)
{
 fsm_timer *this = timer_container_of(this, t, tl);
#if FSM_TIMER_DEBUG
 printk(KERN_DEBUG "fsm(%s): Timer %p expired\n",
        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;
#if FSM_TIMER_DEBUG
 printk(KERN_DEBUG "fsm(%s): Create timer %p\n", fi->name,
        this);
#endif
 timer_setup(&this->tl, fsm_expire_timer, 0);
}

void
fsm_deltimer(fsm_timer *this)
{
#if FSM_TIMER_DEBUG
 printk(KERN_DEBUG "fsm(%s): Delete timer %p\n", this->fi->name,
  this);
#endif
 timer_delete(&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\n",
        this->fi->name, this, millisec);
#endif

 timer_setup(&this->tl, fsm_expire_timer, 0);
 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\n",
  this->fi->name, this, millisec);
#endif

 timer_delete(&this->tl);
 timer_setup(&this->tl, fsm_expire_timer, 0);
 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