lincan/src/can_quekern.c

   1 /* can_quekern.c - CAN message queues functions for the Linux kernel
   2  * Linux CAN-bus device driver.
   3  * New CAN queues by Pavel Pisa - OCERA team member
   4  * email:pisa@cmp.felk.cvut.cz
   5  * This software is released under the GPL-License.
   6  * Version lincan-0.2  9 Jul 2003
   7  */
   8
   9 #include "../include/can.h"
  10 #include "../include/can_sysdep.h"
  11 #include "../include/can_queue.h"
  12
  13 //#define CAN_DEBUG
  14
  15 extern atomic_t edge_num_cnt;
  16
  17 #ifdef CAN_DEBUG
  18         #define DEBUGQUE(fmt,args...) printk(KERN_ERR "can_queue (debug): " fmt,\
  19         ##args)
  20
  21 #else
  22         #define DEBUGQUE(fmt,args...)
  23 #endif
  24
  25 #define ERRMSGQUE(fmt,args...) printk(KERN_ERR "can_queue: " fmt,\
  26         ##args)
  27
  28
  29 /*
  30  * Modifies Tx message processing
  31  *  0 .. local message processing disabled
  32  *  1 .. local messages disabled by default but can be enabled by canque_set_filt
  33  *  2 .. local messages enabled by default, can be disabled by canque_set_filt
  34  */
  35 extern int processlocal;
  36
  37 void canque_dead_func(unsigned long data);
  38
  39 /* Support for dead ends structures left after client close */
  40 spinlock_t canque_dead_func_lock;
  41 LIST_HEAD(canque_dead_ends);
  42 /* retrieved by list_entry(canque_dead_ends.next,struct canque_ends_t,dead_peers) */
  43 LIST_HEAD(canque_dead_edges);
  44 /* retrieved by list_entry(canque_dead_edges.next,struct canque_edge_t,inpeers) */
  45 DECLARE_TASKLET(canque_dead_tl, canque_dead_func, 0);
  46 /* activated by tasklet_schedule(&canque_dead_tl) */
  47
  48
  49 static inline
  50 struct canque_edge_t *canque_dead_edges_cut_first(void)
  51 {
  52         unsigned long flags;
  53         struct canque_edge_t *edge;
  54         spin_lock_irqsave(&canque_dead_func_lock, flags);
  55         if(list_empty(&canque_dead_edges))
  56                 edge=NULL;
  57         else{
  58                 edge=list_entry(canque_dead_edges.next,struct canque_edge_t,inpeers);
  59                 list_del(&edge->inpeers);
  60         }
  61         spin_unlock_irqrestore(&canque_dead_func_lock, flags);
  62         return edge;
  63 }
  64
  65 void canque_dead_func(unsigned long data)
  66 {
  67         unsigned long flags;
  68         struct canque_edge_t *qedge;
  69         struct canque_ends_t *qends;
  70         struct list_head *entry;
  71
  72         while((qedge=canque_dead_edges_cut_first())){
  73                 DEBUGQUE("edge %d disposed\n",qedge->edge_num);
  74                 kfree(qedge);
  75         }
  76
  77         spin_lock_irqsave(&canque_dead_func_lock, flags);
  78         entry=canque_dead_ends.next;
  79         spin_unlock_irqrestore(&canque_dead_func_lock,flags);
  80         while(entry!=&canque_dead_ends){
  81                 qends=list_entry(canque_dead_ends.next,struct canque_ends_t,dead_peers);
  82                 entry=entry->next;
  83                 if(!list_empty(&qends->inlist))
  84                         continue;
  85                 if(!list_empty(&qends->outlist))
  86                         continue;
  87                 spin_lock_irqsave(&canque_dead_func_lock, flags);
  88                 list_del(&qends->dead_peers);
  89                 spin_unlock_irqrestore(&canque_dead_func_lock,flags);
  90                 DEBUGQUE("ends structure disposed\n");
  91                 kfree(qends);
  92         }
  93
  94 }
  95
  96
  97 void canque_edge_do_dead(struct canque_edge_t *edge, int dead_fl)
  98 {
  99         unsigned long flags;
 100
 101         if(dead_fl) return;
 102
 103         if(canqueue_disconnect_edge(edge)<0){
 104                 ERRMSGQUE("canque_edge_do_dead: canqueue_disconnect_edge failed !!!\n");
 105                 return;
 106         }
 107
 108         spin_lock_irqsave(&canque_dead_func_lock, flags);
 109         list_add(&edge->inpeers,&canque_dead_edges);
 110         spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 111         tasklet_schedule(&canque_dead_tl);
 112 }
 113
 114
 115
 116 /*if(qends->ends_flags & CAN_ENDSF_DEAD){
 117         spin_lock_irqsave(&canque_dead_func_lock, flags);
 118         list_del(&qends->dead_peers);
 119         list_add(&qends->dead_peers,&canque_dead_ends);
 120         spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 121         tasklet_schedule(&canque_dead_tl);
 122 }*/
 123
 124
 125 /**
 126  * canqueue_notify_kern - notification callback handler for Linux userspace clients
 127  * @qends: pointer to the callback side ends structure
 128  * @qedge: edge which invoked notification
 129  * @what: notification type
 130  */
 131 void canqueue_notify_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge, int what)
 132 {
 133         DEBUGQUE("canqueue_notify_kern for edge %d, use %d and event %d\n",
 134                         qedge->edge_num,(int)atomic_read(&qedge->edge_used),what);
 135         switch(what){
 136                 case CANQUEUE_NOTIFY_EMPTY:
 137                         wake_up(&qends->endinfo.fileinfo.emptyq);
 138                         if(canque_fifo_test_and_clear_fl(&qedge->fifo, FREEONEMPTY))
 139                                 canque_edge_decref(qedge);
 140                         break;
 141                 case CANQUEUE_NOTIFY_SPACE:
 142                         wake_up(&qends->endinfo.fileinfo.writeq);
 143                         break;
 144                 case CANQUEUE_NOTIFY_PROC:
 145                         wake_up(&qends->endinfo.fileinfo.readq);
 146                         break;
 147                 case CANQUEUE_NOTIFY_NOUSR:
 148                         wake_up(&qends->endinfo.fileinfo.readq);
 149                         wake_up(&qends->endinfo.fileinfo.writeq);
 150                         wake_up(&qends->endinfo.fileinfo.emptyq);
 151                         break;
 152                 case CANQUEUE_NOTIFY_DEAD_WANTED:
 153                 case CANQUEUE_NOTIFY_DEAD:
 154                         if(canque_fifo_test_and_clear_fl(&qedge->fifo, READY))
 155                                 canque_edge_decref(qedge);
 156                         break;
 157                 case CANQUEUE_NOTIFY_ATTACH:
 158                         break;
 159         }
 160 }
 161
 162 /**
 163  * canqueue_ends_init_kern - Linux userspace clients specific ends initialization
 164  * @qends: pointer to the callback side ends structure
 165  */
 166 int canqueue_ends_init_kern(struct canque_ends_t *qends)
 167 {
 168         canqueue_ends_init_gen(qends);
 169         qends->context=NULL;
 170         init_waitqueue_head(&qends->endinfo.fileinfo.readq);
 171         init_waitqueue_head(&qends->endinfo.fileinfo.writeq);
 172         init_waitqueue_head(&qends->endinfo.fileinfo.emptyq);
 173         qends->notify=canqueue_notify_kern;
 174         DEBUGQUE("canqueue_ends_init_kern\n");
 175         return 0;
 176 }
 177
 178
 179 /**
 180  * canque_get_inslot4id_wait_kern - find or wait for best outgoing edge and slot for given ID
 181  * @qends: ends structure belonging to calling communication object
 182  * @qedgep: place to store pointer to found edge
 183  * @slotp: place to store pointer to  allocated slot
 184  * @cmd: command type for slot
 185  * @id: communication ID of message to send into edge
 186  * @prio: optional priority of message
 187  *
 188  * Same as canque_get_inslot4id(), except, that it waits for free slot
 189  * in case, that queue is full. Function is specific for Linux userspace clients.
 190  * Return Value: If there is no usable edge negative value is returned.
 191  */
 192 int canque_get_inslot4id_wait_kern(struct canque_ends_t *qends,
 193         struct canque_edge_t **qedgep, struct canque_slot_t **slotp,
 194         int cmd, unsigned long id, int prio)
 195 {
 196         int ret=-1;
 197         DEBUGQUE("canque_get_inslot4id_wait_kern for cmd %d, id %ld, prio %d\n",cmd,id,prio);
 198         wait_event_interruptible((qends->endinfo.fileinfo.writeq),
 199                 (ret=canque_get_inslot4id(qends,qedgep,slotp,cmd,id,prio))!=-1);
 200         return ret;
 201 }
 202
 203 /**
 204  * canque_get_outslot_wait_kern - receive or wait for ready slot for given ends
 205  * @qends: ends structure belonging to calling communication object
 206  * @qedgep: place to store pointer to found edge
 207  * @slotp: place to store pointer to received slot
 208  *
 209  * The same as canque_test_outslot(), except it waits in the case, that there is
 210  * no ready slot for given ends. Function is specific for Linux userspace clients.
 211  * Return Value: Negative value informs, that there is no ready output
 212  *      slot for given ends. Positive value is equal to the command
 213  *      slot has been allocated by the input side.
 214  */
 215 int canque_get_outslot_wait_kern(struct canque_ends_t *qends,
 216         struct canque_edge_t **qedgep, struct canque_slot_t **slotp)
 217 {
 218         int ret=-1;
 219         DEBUGQUE("canque_get_outslot_wait_kern\n");
 220         wait_event_interruptible((qends->endinfo.fileinfo.readq),
 221                 (ret=canque_test_outslot(qends,qedgep,slotp))!=-1);
 222         return ret;
 223 }
 224
 225 /**
 226  * canque_sync_wait_kern - wait for all slots processing
 227  * @qends: ends structure belonging to calling communication object
 228  * @qedge: pointer to edge
 229  *
 230  * Functions waits for ends transition into empty state.
 231  * Return Value: Positive value indicates, that edge empty state has been reached.
 232  *      Negative or zero value informs about interrupted wait or other problem.
 233  */
 234 int canque_sync_wait_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge)
 235 {
 236         int ret=-1;
 237         DEBUGQUE("canque_sync_wait_kern\n");
 238         wait_event_interruptible((qends->endinfo.fileinfo.emptyq),
 239                 (ret=canque_fifo_test_fl(&qedge->fifo,EMPTY)?1:0));
 240         return ret;
 241 }
 242
 243
 244 /**
 245  * canque_new_edge_kern - allocate new edge structure in the Linux kernel context
 246  * @slotsnr: required number of slots in the newly allocated edge structure
 247  *
 248  * Return Value: Returns pointer to allocated slot structure or %NULL if
 249  *      there is not enough memory to process operation.
 250  */
 251 struct canque_edge_t *canque_new_edge_kern(int slotsnr)
 252 {
 253         struct canque_edge_t *qedge;
 254         qedge = (struct canque_edge_t *)kmalloc(sizeof(struct canque_edge_t), GFP_KERNEL);
 255         if(qedge == NULL) return NULL;
 256
 257         memset(qedge,0,sizeof(struct canque_edge_t));
 258         spin_lock_init(&qedge->fifo.fifo_lock);
 259         if(canque_fifo_init_slots(&qedge->fifo, slotsnr)<0){
 260                 kfree(qedge);
 261                 DEBUGQUE("canque_new_edge_kern failed\n");
 262                 return NULL;
 263         }
 264         atomic_set(&qedge->edge_used,1);
 265         qedge->filtid = 0;
 266         qedge->filtmask = canque_filtid2internal(0l, (processlocal<2)? MSG_LOCAL:0);
 267         qedge->edge_prio = 0;
 268     #ifdef CAN_DEBUG
 269         /* not exactly clean, but enough for debugging */
 270         atomic_inc(&edge_num_cnt);
 271         qedge->edge_num=atomic_read(&edge_num_cnt);
 272     #endif /* CAN_DEBUG */
 273         DEBUGQUE("canque_new_edge_kern %d\n",qedge->edge_num);
 274         return qedge;
 275 }
 276
 277 #ifdef USE_DELAYED_DISCONNECT_EDGE_KERN
 278
 279 /**
 280  * canqueue_disconnect_edge_kern - disconnect edge from communicating entities with wait
 281  * @qends: ends structure belonging to calling communication object
 282  * @qedge: pointer to edge
 283  *
 284  * Same as canqueue_disconnect_edge(), but tries to wait for state with zero
 285  * use counter.
 286  * Return Value: Negative value means, that edge is used and cannot
 287  *      be disconnected yet. Operation has to be delayed.
 288  */
 289 int canqueue_disconnect_edge_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge)
 290 {
 291         canque_fifo_set_fl(&qedge->fifo,BLOCK);
 292         DEBUGQUE("canqueue_disconnect_edge_kern %d called\n",qedge->edge_num);
 293         if(!canque_fifo_test_and_set_fl(&qedge->fifo,DEAD)){
 294                 canque_notify_bothends(qedge, CANQUEUE_NOTIFY_DEAD);
 295
 296                 if(atomic_read(&qedge->edge_used)>0)
 297                         atomic_dec(&qedge->edge_used);
 298
 299                 DEBUGQUE("canqueue_disconnect_edge_kern %d waiting\n",qedge->edge_num);
 300                 wait_event((qends->endinfo.fileinfo.emptyq),
 301                         (canqueue_disconnect_edge(qedge)>=0));
 302
 303                 /*set_current_state(TASK_UNINTERRUPTIBLE);*/
 304                 /*schedule_timeout(HZ);*/
 305                 return 0;
 306         } else {
 307                 DEBUGQUE("canqueue_disconnect_edge_kern cannot set DEAD\n");
 308                 return -1;
 309         }
 310 }
 311
 312
 313 int canqueue_disconnect_list_kern(struct canque_ends_t *qends, struct list_head *list)
 314 {
 315         struct canque_edge_t *edge;
 316         unsigned long flags;
 317         for(;;){
 318                 spin_lock_irqsave(&qends->ends_lock,flags);
 319                 if(list_empty(list)){
 320                         spin_unlock_irqrestore(&qends->ends_lock,flags);
 321                         return 0;
 322                 }
 323                 if(list == &qends->inlist)
 324                         edge=list_entry(list->next,struct canque_edge_t,inpeers);
 325                 else
 326                         edge=list_entry(list->next,struct canque_edge_t,outpeers);
 327                 atomic_inc(&edge->edge_used);
 328                 spin_unlock_irqrestore(&qends->ends_lock,flags);
 329                 if(canqueue_disconnect_edge_kern(qends, edge)>=0) {
 330                         /* Free edge memory */
 331                         canque_fifo_done(&edge->fifo);
 332                         kfree(edge);
 333                 }else{
 334                         canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
 335                         canque_edge_decref(edge);
 336                         DEBUGQUE("canqueue_disconnect_list_kern in troubles\n");
 337                         DEBUGQUE("the edge %d has usage count %d and flags %ld\n",edge->edge_num,atomic_read(&edge->edge_used),edge->fifo.fifo_flags);
 338                         return -1;
 339                 }
 340         }
 341 }
 342
 343 #endif /*USE_DELAYED_DISCONNECT_EDGE_KERN*/
 344
 345
 346 int canqueue_ends_sync_all_kern(struct canque_ends_t *qends)
 347 {
 348         struct canque_edge_t *qedge;
 349
 350         canque_for_each_inedge(qends, qedge){
 351                 DEBUGQUE("canque_sync_wait_kern called for edge %d\n",qedge->edge_num);
 352                 canque_sync_wait_kern(qends, qedge);
 353         }
 354         return 0;
 355 }
 356
 357 int canqueue_ends_done_inends(struct canque_ends_t *qends, int send_rest)
 358 {
 359         struct canque_edge_t *edge;
 360
 361         canque_for_each_inedge(qends, edge){
 362                 canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
 363                 if(send_rest){
 364                         canque_edge_incref(edge);
 365                         if(!canque_fifo_test_and_set_fl(&edge->fifo, FREEONEMPTY)){
 366                                 if(!canque_fifo_test_fl(&edge->fifo, EMPTY))
 367                                         continue;
 368                                 if(!canque_fifo_test_and_clear_fl(&edge->fifo, FREEONEMPTY))
 369                                         continue;
 370                         }
 371                         canque_edge_decref(edge);
 372                 }
 373         }
 374         return list_empty(&qends->inlist)?0:1;
 375 }
 376
 377
 378 int canqueue_ends_done_outends(struct canque_ends_t *qends)
 379 {
 380         struct canque_edge_t *edge;
 381
 382         canque_for_each_outedge(qends, edge){
 383                 canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
 384         }
 385         return list_empty(&qends->outlist)?0:1;
 386 }
 387
 388
 389 /**
 390  * canqueue_ends_dispose_kern - finalizing of the ends structure for Linux kernel clients
 391  * @qends: pointer to ends structure
 392  * @sync: flag indicating, that user wants to wait for processing of all remaining
 393  *      messages
 394  *
 395  * Return Value: Function should be designed such way to not fail.
 396  */
 397 int canqueue_ends_dispose_kern(struct canque_ends_t *qends, int sync)
 398 {
 399         unsigned long flags;
 400         int delayed;
 401
 402         DEBUGQUE("canqueue_ends_dispose_kern\n");
 403         canqueue_block_inlist(qends);
 404         canqueue_block_outlist(qends);
 405
 406         /*Wait for sending of all pending messages in the output FIFOs*/
 407         if(sync)
 408                 canqueue_ends_sync_all_kern(qends);
 409
 410         /* Finish all outgoing edges listed in inends */
 411         delayed=canqueue_ends_done_inends(qends, 1);
 412
 413         delayed|=canqueue_ends_done_outends(qends);
 414
 415         wake_up(&qends->endinfo.fileinfo.readq);
 416         wake_up(&qends->endinfo.fileinfo.writeq);
 417         wake_up(&qends->endinfo.fileinfo.emptyq);
 418
 419         if(delayed){
 420                 spin_lock_irqsave(&canque_dead_func_lock, flags);
 421                 qends->ends_flags |= CAN_ENDSF_DEAD;
 422                 list_add(&qends->dead_peers,&canque_dead_ends);
 423                 spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 424                 tasklet_schedule(&canque_dead_tl);
 425
 426                 DEBUGQUE("canqueue_ends_dispose_kern delayed\n");
 427                 return 1;
 428         }
 429
 430         kfree(qends);
 431         DEBUGQUE("canqueue_ends_dispose_kern finished\n");
 432         return 0;
 433 }
 434
 435 void canqueue_kern_initialize()
 436 {
 437
 438
 439 }