fsm.c

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

MODULE_AUTHOR("(C) 2000 IBM Corp. by Fritz Elfert ([email protected])");
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;
    }
    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\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(fsm_timer *this)
{
#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;
    this->tl.function = (void *)fsm_expire_timer;
    this->tl.data = (long)this;
#if FSM_TIMER_DEBUG
    printk(KERN_DEBUG "fsm(%s): Create timer %p\n", 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\n", 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\n",
           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\n",
        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