drivers/s390/net/fsm.h

   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 <linux/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         wait_queue_head_t wait_q;
  70 #if FSM_DEBUG_HISTORY
  71         int         history_index;
  72         int         history_size;
  73         fsm_history history[FSM_HISTORY_SIZE];
  74 #endif
  75 } fsm_instance;
  76
  77 /**
  78  * Description of a state-event combination
  79  */
  80 typedef struct {
  81         int cond_state;
  82         int cond_event;
  83         fsm_function_t function;
  84 } fsm_node;
  85
  86 /**
  87  * Description of a FSM Timer.
  88  */
  89 typedef struct {
  90         fsm_instance *fi;
  91         struct timer_list tl;
  92         int expire_event;
  93         void *event_arg;
  94 } fsm_timer;
  95
  96 /**
  97  * Creates an FSM
  98  *
  99  * @param name        Name of this instance for logging purposes.
 100  * @param state_names An array of names for all states for logging purposes.
 101  * @param event_names An array of names for all events for logging purposes.
 102  * @param nr_states   Number of states for this instance.
 103  * @param nr_events   Number of events for this instance.
 104  * @param tmpl        An array of fsm_nodes, describing this FSM.
 105  * @param tmpl_len    Length of the describing array.
 106  * @param order       Parameter for allocation of the FSM data structs.
 107  */
 108 extern fsm_instance *
 109 init_fsm(char *name, const char **state_names,
 110          const char **event_names,
 111          int nr_states, int nr_events, const fsm_node *tmpl,
 112          int tmpl_len, gfp_t order);
 113
 114 /**
 115  * Releases an FSM
 116  *
 117  * @param fi Pointer to an FSM, previously created with init_fsm.
 118  */
 119 extern void kfree_fsm(fsm_instance *fi);
 120
 121 #if FSM_DEBUG_HISTORY
 122 extern void
 123 fsm_print_history(fsm_instance *fi);
 124
 125 extern void
 126 fsm_record_history(fsm_instance *fi, int state, int event);
 127 #endif
 128
 129 /**
 130  * Emits an event to a FSM.
 131  * If an action function is defined for the current state/event combination,
 132  * this function is called.
 133  *
 134  * @param fi    Pointer to FSM which should receive the event.
 135  * @param event The event do be delivered.
 136  * @param arg   A generic argument, handed to the action function.
 137  *
 138  * @return      0  on success,
 139  *              1  if current state or event is out of range
 140  *              !0 if state and event in range, but no action defined.
 141  */
 142 static inline int
 143 fsm_event(fsm_instance *fi, int event, void *arg)
 144 {
 145         fsm_function_t r;
 146         int state = atomic_read(&fi->state);
 147
 148         if ((state >= fi->f->nr_states) ||
 149             (event >= fi->f->nr_events)       ) {
 150                 printk(KERN_ERR "fsm(%s): Invalid state st(%ld/%ld) ev(%d/%ld)\n",
 151                         fi->name, (long)state,(long)fi->f->nr_states, event,
 152                         (long)fi->f->nr_events);
 153 #if FSM_DEBUG_HISTORY
 154                 fsm_print_history(fi);
 155 #endif
 156                 return 1;
 157         }
 158         r = fi->f->jumpmatrix[fi->f->nr_states * event + state];
 159         if (r) {
 160 #if FSM_DEBUG
 161                 printk(KERN_DEBUG "fsm(%s): state %s event %s\n",
 162                        fi->name, fi->f->state_names[state],
 163                        fi->f->event_names[event]);
 164 #endif
 165 #if FSM_DEBUG_HISTORY
 166                 fsm_record_history(fi, state, event);
 167 #endif
 168                 r(fi, event, arg);
 169                 return 0;
 170         } else {
 171 #if FSM_DEBUG || FSM_DEBUG_HISTORY
 172                 printk(KERN_DEBUG "fsm(%s): no function for event %s in state %s\n",
 173                        fi->name, fi->f->event_names[event],
 174                        fi->f->state_names[state]);
 175 #endif
 176 #if FSM_DEBUG_HISTORY
 177                 fsm_print_history(fi);
 178 #endif
 179                 return !0;
 180         }
 181 }
 182
 183 /**
 184  * Modifies the state of an FSM.
 185  * This does <em>not</em> trigger an event or calls an action function.
 186  *
 187  * @param fi    Pointer to FSM
 188  * @param state The new state for this FSM.
 189  */
 190 static inline void
 191 fsm_newstate(fsm_instance *fi, int newstate)
 192 {
 193         atomic_set(&fi->state,newstate);
 194 #if FSM_DEBUG_HISTORY
 195         fsm_record_history(fi, newstate, -1);
 196 #endif
 197 #if FSM_DEBUG
 198         printk(KERN_DEBUG "fsm(%s): New state %s\n", fi->name,
 199                 fi->f->state_names[newstate]);
 200 #endif
 201         wake_up(&fi->wait_q);
 202 }
 203
 204 /**
 205  * Retrieves the state of an FSM
 206  *
 207  * @param fi Pointer to FSM
 208  *
 209  * @return The current state of the FSM.
 210  */
 211 static inline int
 212 fsm_getstate(fsm_instance *fi)
 213 {
 214         return atomic_read(&fi->state);
 215 }
 216
 217 /**
 218  * Retrieves the name of the state of an FSM
 219  *
 220  * @param fi Pointer to FSM
 221  *
 222  * @return The current state of the FSM in a human readable form.
 223  */
 224 extern const char *fsm_getstate_str(fsm_instance *fi);
 225
 226 /**
 227  * Initializes a timer for an FSM.
 228  * This prepares an fsm_timer for usage with fsm_addtimer.
 229  *
 230  * @param fi    Pointer to FSM
 231  * @param timer The timer to be initialized.
 232  */
 233 extern void fsm_settimer(fsm_instance *fi, fsm_timer *);
 234
 235 /**
 236  * Clears a pending timer of an FSM instance.
 237  *
 238  * @param timer The timer to clear.
 239  */
 240 extern void fsm_deltimer(fsm_timer *timer);
 241
 242 /**
 243  * Adds and starts a timer to an FSM instance.
 244  *
 245  * @param timer    The timer to be added. The field fi of that timer
 246  *                 must have been set to point to the instance.
 247  * @param millisec Duration, after which the timer should expire.
 248  * @param event    Event, to trigger if timer expires.
 249  * @param arg      Generic argument, provided to expiry function.
 250  *
 251  * @return         0 on success, -1 if timer is already active.
 252  */
 253 extern int fsm_addtimer(fsm_timer *timer, int millisec, int event, void *arg);
 254
 255 /**
 256  * Modifies a timer of an FSM.
 257  *
 258  * @param timer    The timer to modify.
 259  * @param millisec Duration, after which the timer should expire.
 260  * @param event    Event, to trigger if timer expires.
 261  * @param arg      Generic argument, provided to expiry function.
 262  */
 263 extern void fsm_modtimer(fsm_timer *timer, int millisec, int event, void *arg);
 264
 265 #endif /* _FSM_H_ */