1 #ifndef _FSM_H_
2 #define _FSM_H_
3
4 #include <linux/kernel.h>
5 #include <linux/types.h>
6 #include <linux/timer.h>
7 #include <linux/time.h>
8 #include <linux/slab.h>
9 #include <linux/sched.h>
10 #include <linux/string.h>
11 #include <asm/atomic.h>
12
13 /**
14 * Define this to get debugging messages.
15 */
16 #define FSM_DEBUG 0
17
18 /**
19 * Define this to get debugging massages for
20 * timer handling.
21 */
22 #define FSM_TIMER_DEBUG 0
23
24 /**
25 * Define these to record a history of
26 * Events/Statechanges and print it if a
27 * action_function is not found.
28 */
29 #define FSM_DEBUG_HISTORY 0
30 #define FSM_HISTORY_SIZE 40
31
32 struct fsm_instance_t;
33
34 /**
35 * Definition of an action function, called by a FSM
36 */
37 typedef void (*fsm_function_t)(struct fsm_instance_t *, int, void *);
38
39 /**
40 * Internal jump table for a FSM
41 */
42 typedef struct {
43 fsm_function_t *jumpmatrix;
44 int nr_events;
45 int nr_states;
46 const char **event_names;
47 const char **state_names;
48 } fsm;
49
50 #if FSM_DEBUG_HISTORY
51 /**
52 * Element of State/Event history used for debugging.
53 */
54 typedef struct {
55 int state;
56 int event;
57 } fsm_history;
58 #endif
59
60 /**
61 * Representation of a FSM
62 */
63 typedef struct fsm_instance_t {
64 fsm *f;
65 atomic_t state;
66 char name[16];
67 void *userdata;
68 int userint;
69 #if FSM_DEBUG_HISTORY
70 int history_index;
71 int history_size;
72 fsm_history history[FSM_HISTORY_SIZE];
73 #endif
74 } fsm_instance;
75
76 /**
77 * Description of a state-event combination
78 */
79 typedef struct {
80 int cond_state;
81 int cond_event;
82 fsm_function_t function;
83 } fsm_node;
84
85 /**
86 * Description of a FSM Timer.
87 */
88 typedef struct {
89 fsm_instance *fi;
90 struct timer_list tl;
91 int expire_event;
92 void *event_arg;
93 } fsm_timer;
94
95 /**
96 * Creates an FSM
97 *
98 * @param name Name of this instance for logging purposes.
99 * @param state_names An array of names for all states for logging purposes.
100 * @param event_names An array of names for all events for logging purposes.
101 * @param nr_states Number of states for this instance.
102 * @param nr_events Number of events for this instance.
103 * @param tmpl An array of fsm_nodes, describing this FSM.
104 * @param tmpl_len Length of the describing array.
105 * @param order Parameter for allocation of the FSM data structs.
106 */
107 extern fsm_instance *
108 init_fsm(char *name, const char **state_names,
109 const char **event_names,
110 int nr_states, int nr_events, const fsm_node *tmpl,
111 int tmpl_len, gfp_t order);
112
113 /**
114 * Releases an FSM
115 *
116 * @param fi Pointer to an FSM, previously created with init_fsm.
117 */
118 extern void kfree_fsm(fsm_instance *fi);
119
120 #if FSM_DEBUG_HISTORY
121 extern void
122 fsm_print_history(fsm_instance *fi);
123
124 extern void
125 fsm_record_history(fsm_instance *fi, int state, int event);
126 #endif
127
128 /**
129 * Emits an event to a FSM.
130 * If an action function is defined for the current state/event combination,
131 * this function is called.
132 *
133 * @param fi Pointer to FSM which should receive the event.
134 * @param event The event do be delivered.
135 * @param arg A generic argument, handed to the action function.
136 *
137 * @return 0 on success,
138 * 1 if current state or event is out of range
139 * !0 if state and event in range, but no action defined.
140 */
141 static inline int
142 fsm_event(fsm_instance *fi, int event, void *arg)
143 {
144 fsm_function_t r;
145 int state = atomic_read(&fi->state);
146
147 if ((state >= fi->f->nr_states) ||
148 (event >= fi->f->nr_events) ) {
149 printk(KERN_ERR "fsm(%s): Invalid state st(%ld/%ld) ev(%d/%ld)\n",
150 fi->name, (long)state,(long)fi->f->nr_states, event,
151 (long)fi->f->nr_events);
152 #if FSM_DEBUG_HISTORY
153 fsm_print_history(fi);
154 #endif
155 return 1;
156 }
157 r = fi->f->jumpmatrix[fi->f->nr_states * event + state];
158 if (r) {
159 #if FSM_DEBUG
160 printk(KERN_DEBUG "fsm(%s): state %s event %s\n",
161 fi->name, fi->f->state_names[state],
162 fi->f->event_names[event]);
163 #endif
164 #if FSM_DEBUG_HISTORY
165 fsm_record_history(fi, state, event);
166 #endif
167 r(fi, event, arg);
168 return 0;
169 } else {
170 #if FSM_DEBUG || FSM_DEBUG_HISTORY
171 printk(KERN_DEBUG "fsm(%s): no function for event %s in state %s\n",
172 fi->name, fi->f->event_names[event],
173 fi->f->state_names[state]);
174 #endif
175 #if FSM_DEBUG_HISTORY
176 fsm_print_history(fi);
177 #endif
178 return !0;
179 }
180 }
181
182 /**
183 * Modifies the state of an FSM.
184 * This does <em>not</em> trigger an event or calls an action function.
185 *
186 * @param fi Pointer to FSM
187 * @param state The new state for this FSM.
188 */
189 static inline void
190 fsm_newstate(fsm_instance *fi, int newstate)
191 {
192 atomic_set(&fi->state,newstate);
193 #if FSM_DEBUG_HISTORY
194 fsm_record_history(fi, newstate, -1);
195 #endif
196 #if FSM_DEBUG
197 printk(KERN_DEBUG "fsm(%s): New state %s\n", fi->name,
198 fi->f->state_names[newstate]);
199 #endif
200 }
201
202 /**
203 * Retrieves the state of an FSM
204 *
205 * @param fi Pointer to FSM
206 *
207 * @return The current state of the FSM.
208 */
209 static inline int
210 fsm_getstate(fsm_instance *fi)
211 {
212 return atomic_read(&fi->state);
213 }
214
215 /**
216 * Retrieves the name of the state of an FSM
217 *
218 * @param fi Pointer to FSM
219 *
220 * @return The current state of the FSM in a human readable form.
221 */
222 extern const char *fsm_getstate_str(fsm_instance *fi);
223
224 /**
225 * Initializes a timer for an FSM.
226 * This prepares an fsm_timer for usage with fsm_addtimer.
227 *
228 * @param fi Pointer to FSM
229 * @param timer The timer to be initialized.
230 */
231 extern void fsm_settimer(fsm_instance *fi, fsm_timer *);
232
233 /**
234 * Clears a pending timer of an FSM instance.
235 *
236 * @param timer The timer to clear.
237 */
238 extern void fsm_deltimer(fsm_timer *timer);
239
240 /**
241 * Adds and starts a timer to an FSM instance.
242 *
243 * @param timer The timer to be added. The field fi of that timer
244 * must have been set to point to the instance.
245 * @param millisec Duration, after which the timer should expire.
246 * @param event Event, to trigger if timer expires.
247 * @param arg Generic argument, provided to expiry function.
248 *
249 * @return 0 on success, -1 if timer is already active.
250 */
251 extern int fsm_addtimer(fsm_timer *timer, int millisec, int event, void *arg);
252
253 /**
254 * Modifies a timer of an FSM.
255 *
256 * @param timer The timer to modify.
257 * @param millisec Duration, after which the timer should expire.
258 * @param event Event, to trigger if timer expires.
259 * @param arg Generic argument, provided to expiry function.
260 */
261 extern void fsm_modtimer(fsm_timer *timer, int millisec, int event, void *arg);
262
263 #endif /* _FSM_H_ */
264
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