1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * A generic FSM based on fsm used in isdn4linux
4 *
5 */
6
7 #include "fsm.h"
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/timer.h>
11
12 MODULE_AUTHOR("(C) 2000 IBM Corp. by Fritz Elfert (felfert@millenux.com)");
13 MODULE_DESCRIPTION("Finite state machine helper functions");
14 MODULE_LICENSE("GPL");
15
16 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)17 init_fsm(char *name, const char **state_names, const char **event_names, int nr_states,
18 int nr_events, const fsm_node *tmpl, int tmpl_len, gfp_t order)
19 {
20 int i;
21 fsm_instance *this;
22 fsm_function_t *m;
23 fsm *f;
24
25 this = kzalloc(sizeof(fsm_instance), order);
26 if (this == NULL) {
27 printk(KERN_WARNING
28 "fsm(%s): init_fsm: Couldn't alloc instance\n", name);
29 return NULL;
30 }
31 strlcpy(this->name, name, sizeof(this->name));
32 init_waitqueue_head(&this->wait_q);
33
34 f = kzalloc(sizeof(fsm), order);
35 if (f == NULL) {
36 printk(KERN_WARNING
37 "fsm(%s): init_fsm: Couldn't alloc fsm\n", name);
38 kfree_fsm(this);
39 return NULL;
40 }
41 f->nr_events = nr_events;
42 f->nr_states = nr_states;
43 f->event_names = event_names;
44 f->state_names = state_names;
45 this->f = f;
46
47 m = kcalloc(nr_states*nr_events, sizeof(fsm_function_t), order);
48 if (m == NULL) {
49 printk(KERN_WARNING
50 "fsm(%s): init_fsm: Couldn't alloc jumptable\n", name);
51 kfree_fsm(this);
52 return NULL;
53 }
54 f->jumpmatrix = m;
55
56 for (i = 0; i < tmpl_len; i++) {
57 if ((tmpl[i].cond_state >= nr_states) ||
58 (tmpl[i].cond_event >= nr_events) ) {
59 printk(KERN_ERR
60 "fsm(%s): init_fsm: Bad template l=%d st(%ld/%ld) ev(%ld/%ld)\n",
61 name, i, (long)tmpl[i].cond_state, (long)f->nr_states,
62 (long)tmpl[i].cond_event, (long)f->nr_events);
63 kfree_fsm(this);
64 return NULL;
65 } else
66 m[nr_states * tmpl[i].cond_event + tmpl[i].cond_state] =
67 tmpl[i].function;
68 }
69 return this;
70 }
71
72 void
kfree_fsm(fsm_instance * this)73 kfree_fsm(fsm_instance *this)
74 {
75 if (this) {
76 if (this->f) {
77 kfree(this->f->jumpmatrix);
78 kfree(this->f);
79 }
80 kfree(this);
81 } else
82 printk(KERN_WARNING
83 "fsm: kfree_fsm called with NULL argument\n");
84 }
85
86 #if FSM_DEBUG_HISTORY
87 void
fsm_print_history(fsm_instance * fi)88 fsm_print_history(fsm_instance *fi)
89 {
90 int idx = 0;
91 int i;
92
93 if (fi->history_size >= FSM_HISTORY_SIZE)
94 idx = fi->history_index;
95
96 printk(KERN_DEBUG "fsm(%s): History:\n", fi->name);
97 for (i = 0; i < fi->history_size; i++) {
98 int e = fi->history[idx].event;
99 int s = fi->history[idx++].state;
100 idx %= FSM_HISTORY_SIZE;
101 if (e == -1)
102 printk(KERN_DEBUG " S=%s\n",
103 fi->f->state_names[s]);
104 else
105 printk(KERN_DEBUG " S=%s E=%s\n",
106 fi->f->state_names[s],
107 fi->f->event_names[e]);
108 }
109 fi->history_size = fi->history_index = 0;
110 }
111
112 void
fsm_record_history(fsm_instance * fi,int state,int event)113 fsm_record_history(fsm_instance *fi, int state, int event)
114 {
115 fi->history[fi->history_index].state = state;
116 fi->history[fi->history_index++].event = event;
117 fi->history_index %= FSM_HISTORY_SIZE;
118 if (fi->history_size < FSM_HISTORY_SIZE)
119 fi->history_size++;
120 }
121 #endif
122
123 const char *
fsm_getstate_str(fsm_instance * fi)124 fsm_getstate_str(fsm_instance *fi)
125 {
126 int st = atomic_read(&fi->state);
127 if (st >= fi->f->nr_states)
128 return "Invalid";
129 return fi->f->state_names[st];
130 }
131
132 static void
fsm_expire_timer(struct timer_list * t)133 fsm_expire_timer(struct timer_list *t)
134 {
135 fsm_timer *this = from_timer(this, t, tl);
136 #if FSM_TIMER_DEBUG
137 printk(KERN_DEBUG "fsm(%s): Timer %p expired\n",
138 this->fi->name, this);
139 #endif
140 fsm_event(this->fi, this->expire_event, this->event_arg);
141 }
142
143 void
fsm_settimer(fsm_instance * fi,fsm_timer * this)144 fsm_settimer(fsm_instance *fi, fsm_timer *this)
145 {
146 this->fi = fi;
147 #if FSM_TIMER_DEBUG
148 printk(KERN_DEBUG "fsm(%s): Create timer %p\n", fi->name,
149 this);
150 #endif
151 timer_setup(&this->tl, fsm_expire_timer, 0);
152 }
153
154 void
fsm_deltimer(fsm_timer * this)155 fsm_deltimer(fsm_timer *this)
156 {
157 #if FSM_TIMER_DEBUG
158 printk(KERN_DEBUG "fsm(%s): Delete timer %p\n", this->fi->name,
159 this);
160 #endif
161 del_timer(&this->tl);
162 }
163
164 int
fsm_addtimer(fsm_timer * this,int millisec,int event,void * arg)165 fsm_addtimer(fsm_timer *this, int millisec, int event, void *arg)
166 {
167
168 #if FSM_TIMER_DEBUG
169 printk(KERN_DEBUG "fsm(%s): Add timer %p %dms\n",
170 this->fi->name, this, millisec);
171 #endif
172
173 timer_setup(&this->tl, fsm_expire_timer, 0);
174 this->expire_event = event;
175 this->event_arg = arg;
176 this->tl.expires = jiffies + (millisec * HZ) / 1000;
177 add_timer(&this->tl);
178 return 0;
179 }
180
181 /* FIXME: this function is never used, why */
182 void
fsm_modtimer(fsm_timer * this,int millisec,int event,void * arg)183 fsm_modtimer(fsm_timer *this, int millisec, int event, void *arg)
184 {
185
186 #if FSM_TIMER_DEBUG
187 printk(KERN_DEBUG "fsm(%s): Restart timer %p %dms\n",
188 this->fi->name, this, millisec);
189 #endif
190
191 del_timer(&this->tl);
192 timer_setup(&this->tl, fsm_expire_timer, 0);
193 this->expire_event = event;
194 this->event_arg = arg;
195 this->tl.expires = jiffies + (millisec * HZ) / 1000;
196 add_timer(&this->tl);
197 }
198
199 EXPORT_SYMBOL(init_fsm);
200 EXPORT_SYMBOL(kfree_fsm);
201 EXPORT_SYMBOL(fsm_settimer);
202 EXPORT_SYMBOL(fsm_deltimer);
203 EXPORT_SYMBOL(fsm_addtimer);
204 EXPORT_SYMBOL(fsm_modtimer);
205 EXPORT_SYMBOL(fsm_getstate_str);
206
207 #if FSM_DEBUG_HISTORY
208 EXPORT_SYMBOL(fsm_print_history);
209 EXPORT_SYMBOL(fsm_record_history);
210 #endif
211