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...) can_printk(KERN_ERR "can_quekern (debug): " fmt,\
  19         ##args)
  20
  21 #else
  22         #define DEBUGQUE(fmt,args...)
  23 #endif
  24
  25 #define ERRMSGQUE(fmt,args...) can_printk(KERN_ERR "can_quekern: " 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 can_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         can_spin_irqflags_t flags;
  53         struct canque_edge_t *edge;
  54         can_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         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
  62         return edge;
  63 }
  64
  65 void canque_dead_func(unsigned long data)
  66 {
  67         can_spin_irqflags_t 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             #ifdef CAN_WITH_RTL
  75                 if(canque_fifo_test_fl(&qedge->fifo,RTL_MEM)){
  76                         canque_dispose_edge_rtl(qedge);
  77                         continue;
  78                 }
  79             #endif /*CAN_WITH_RTL*/
  80                 canque_fifo_done_kern(&qedge->fifo);
  81                 kfree(qedge);
  82         }
  83
  84         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
  85         entry=canque_dead_ends.next;
  86         can_spin_unlock_irqrestore(&canque_dead_func_lock,flags);
  87         /* lock can be released there, because only one instance of canque_dead_tl
  88            can run at once and all other functions add ends only to head */
  89         while(entry!=&canque_dead_ends){
  90                 qends=list_entry(entry,struct canque_ends_t,dead_peers);
  91                 entry=entry->next;
  92                 if(!list_empty(&qends->inlist))
  93                         continue;
  94                 if(!list_empty(&qends->outlist))
  95                         continue;
  96                 can_spin_lock_irqsave(&canque_dead_func_lock, flags);
  97                 list_del(&qends->dead_peers);
  98                 can_spin_unlock_irqrestore(&canque_dead_func_lock,flags);
  99                 DEBUGQUE("ends structure disposed\n");
 100             #ifdef CAN_WITH_RTL
 101                 if(qends->ends_flags&CAN_ENDSF_MEM_RTL){
 102                         canque_ends_free_rtl(qends);
 103                         continue;
 104                 }
 105             #endif /*CAN_WITH_RTL*/
 106                 kfree(qends);
 107         }
 108
 109 }
 110
 111 static inline void canque_dead_tasklet_schedule(void)
 112 {
 113     #ifdef CAN_WITH_RTL
 114         if(!rtl_rt_system_is_idle()){
 115                 set_bit(CAN_RTL2LIN_PEND_DEAD_b,&canqueue_rtl2lin_pend);
 116                 rtl_global_pend_irq (canqueue_rtl_irq);
 117                 return;
 118         }
 119     #endif /*CAN_WITH_RTL*/
 120
 121         tasklet_schedule(&canque_dead_tl);
 122 }
 123
 124
 125 void canque_edge_do_dead(struct canque_edge_t *edge, int dead_fl)
 126 {
 127         can_spin_irqflags_t flags;
 128
 129         if(dead_fl) return;
 130
 131         canque_notify_bothends(edge,CANQUEUE_NOTIFY_NOUSR);
 132     #ifdef CAN_WITH_RTL
 133         /* The problem of the above call is, that in RT-Linux to Linux notify
 134            case is edge scheduled for delayed notify delivery, this needs
 135            to be reflected there */
 136         if(atomic_read(&edge->edge_used)>0){
 137                 can_spin_lock_irqsave(&edge->inends->ends_lock, flags);
 138                 can_spin_lock(&edge->outends->ends_lock);
 139                 if(atomic_read(&edge->edge_used)>0){
 140                         /* left edge to live for a while, banshee comes again in a while */
 141                         canque_fifo_clear_fl(&edge->fifo,DEAD);
 142                         can_spin_unlock(&edge->outends->ends_lock);
 143                         can_spin_unlock_irqrestore(&edge->inends->ends_lock, flags);
 144                         can_printk(KERN_ERR "can_quertl (debug): canque_edge_do_dead postponed\n");
 145                         return;
 146                 }
 147                 can_spin_unlock(&edge->outends->ends_lock);
 148                 can_spin_unlock_irqrestore(&edge->inends->ends_lock, flags);
 149         }
 150     #endif /*CAN_WITH_RTL*/
 151
 152         if(canqueue_disconnect_edge(edge)<0){
 153                 ERRMSGQUE("canque_edge_do_dead: canqueue_disconnect_edge failed !!!\n");
 154                 return;
 155         }
 156
 157         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
 158         list_add(&edge->inpeers,&canque_dead_edges);
 159         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 160         canque_dead_tasklet_schedule();
 161 }
 162
 163
 164
 165 /*if(qends->ends_flags & CAN_ENDSF_DEAD){
 166         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
 167         list_del(&qends->dead_peers);
 168         list_add(&qends->dead_peers,&canque_dead_ends);
 169         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 170         tasklet_schedule(&canque_dead_tl);
 171 }*/
 172
 173
 174 /**
 175  * canqueue_notify_kern - notification callback handler for Linux userspace clients
 176  * @qends: pointer to the callback side ends structure
 177  * @qedge: edge which invoked notification
 178  * @what: notification type
 179  *
 180  * The notification event is handled directly by call of this function except case,
 181  * when called from RT-Linux context in mixed mode Linux/RT-Linux compilation.
 182  * It is not possible to directly call Linux kernel synchronization primitives
 183  * in such case. The notification request is postponed and signaled by @pending_inops flags
 184  * by call canqueue_rtl2lin_check_and_pend() function.
 185  * The edge reference count is increased until until all pending notifications are processed.
 186  */
 187 void canqueue_notify_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge, int what)
 188 {
 189         DEBUGQUE("canqueue_notify_kern for edge %d, use %d and event %d\n",
 190                         qedge->edge_num,(int)atomic_read(&qedge->edge_used),what);
 191
 192         /* delay event delivery for RT-Linux -> kernel notifications */
 193         if(canqueue_rtl2lin_check_and_pend(qends,qedge,what)){
 194                 DEBUGQUE("canqueue_notify_kern postponed\n");
 195                 return;
 196         }
 197
 198         switch(what){
 199                 case CANQUEUE_NOTIFY_EMPTY:
 200                         wake_up(&qends->endinfo.fileinfo.emptyq);
 201                         if(canque_fifo_test_and_clear_fl(&qedge->fifo, FREEONEMPTY))
 202                                 canque_edge_decref(qedge);
 203                         break;
 204                 case CANQUEUE_NOTIFY_SPACE:
 205                         wake_up(&qends->endinfo.fileinfo.writeq);
 206                     #ifdef CAN_ENABLE_KERN_FASYNC
 207                         /* Asynchronous I/O processing */
 208                         kill_fasync(&qends->endinfo.fileinfo.fasync, SIGIO, POLL_OUT);
 209                     #endif /*CAN_ENABLE_KERN_FASYNC*/
 210                         break;
 211                 case CANQUEUE_NOTIFY_PROC:
 212                         wake_up(&qends->endinfo.fileinfo.readq);
 213                     #ifdef CAN_ENABLE_KERN_FASYNC
 214                         /* Asynchronous I/O processing */
 215                         kill_fasync(&qends->endinfo.fileinfo.fasync, SIGIO, POLL_IN);
 216                     #endif /*CAN_ENABLE_KERN_FASYNC*/
 217                         break;
 218                 case CANQUEUE_NOTIFY_NOUSR:
 219                         wake_up(&qends->endinfo.fileinfo.readq);
 220                         wake_up(&qends->endinfo.fileinfo.writeq);
 221                         wake_up(&qends->endinfo.fileinfo.emptyq);
 222                         break;
 223                 case CANQUEUE_NOTIFY_DEAD_WANTED:
 224                 case CANQUEUE_NOTIFY_DEAD:
 225                         if(canque_fifo_test_and_clear_fl(&qedge->fifo, READY))
 226                                 canque_edge_decref(qedge);
 227                         break;
 228                 case CANQUEUE_NOTIFY_ATTACH:
 229                         break;
 230         }
 231 }
 232
 233 /**
 234  * canqueue_ends_init_kern - Linux userspace clients specific ends initialization
 235  * @qends: pointer to the callback side ends structure
 236  */
 237 int canqueue_ends_init_kern(struct canque_ends_t *qends)
 238 {
 239         canqueue_ends_init_gen(qends);
 240         qends->context=NULL;
 241         init_waitqueue_head(&qends->endinfo.fileinfo.readq);
 242         init_waitqueue_head(&qends->endinfo.fileinfo.writeq);
 243         init_waitqueue_head(&qends->endinfo.fileinfo.emptyq);
 244     #ifdef CAN_ENABLE_KERN_FASYNC
 245         qends->endinfo.fileinfo.fasync=NULL;
 246     #endif /*CAN_ENABLE_KERN_FASYNC*/
 247
 248         qends->notify=canqueue_notify_kern;
 249         DEBUGQUE("canqueue_ends_init_kern\n");
 250         return 0;
 251 }
 252
 253
 254 /**
 255  * canque_get_inslot4id_wait_kern - find or wait for best outgoing edge and slot for given ID
 256  * @qends: ends structure belonging to calling communication object
 257  * @qedgep: place to store pointer to found edge
 258  * @slotp: place to store pointer to  allocated slot
 259  * @cmd: command type for slot
 260  * @id: communication ID of message to send into edge
 261  * @prio: optional priority of message
 262  *
 263  * Same as canque_get_inslot4id(), except, that it waits for free slot
 264  * in case, that queue is full. Function is specific for Linux userspace clients.
 265  * Return Value: If there is no usable edge negative value is returned.
 266  */
 267 int canque_get_inslot4id_wait_kern(struct canque_ends_t *qends,
 268         struct canque_edge_t **qedgep, struct canque_slot_t **slotp,
 269         int cmd, unsigned long id, int prio)
 270 {
 271         int ret=-1;
 272         DEBUGQUE("canque_get_inslot4id_wait_kern for cmd %d, id %ld, prio %d\n",cmd,id,prio);
 273         wait_event_interruptible((qends->endinfo.fileinfo.writeq),
 274                 (ret=canque_get_inslot4id(qends,qedgep,slotp,cmd,id,prio))!=-1);
 275         return ret;
 276 }
 277
 278 /**
 279  * canque_get_outslot_wait_kern - receive or wait for ready slot for given ends
 280  * @qends: ends structure belonging to calling communication object
 281  * @qedgep: place to store pointer to found edge
 282  * @slotp: place to store pointer to received slot
 283  *
 284  * The same as canque_test_outslot(), except it waits in the case, that there is
 285  * no ready slot for given ends. Function is specific for Linux userspace clients.
 286  * Return Value: Negative value informs, that there is no ready output
 287  *      slot for given ends. Positive value is equal to the command
 288  *      slot has been allocated by the input side.
 289  */
 290 int canque_get_outslot_wait_kern(struct canque_ends_t *qends,
 291         struct canque_edge_t **qedgep, struct canque_slot_t **slotp)
 292 {
 293         int ret=-1;
 294         DEBUGQUE("canque_get_outslot_wait_kern\n");
 295         wait_event_interruptible((qends->endinfo.fileinfo.readq),
 296                 (ret=canque_test_outslot(qends,qedgep,slotp))!=-1);
 297         return ret;
 298 }
 299
 300 /**
 301  * canque_sync_wait_kern - wait for all slots processing
 302  * @qends: ends structure belonging to calling communication object
 303  * @qedge: pointer to edge
 304  *
 305  * Functions waits for ends transition into empty state.
 306  * Return Value: Positive value indicates, that edge empty state has been reached.
 307  *      Negative or zero value informs about interrupted wait or other problem.
 308  */
 309 int canque_sync_wait_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge)
 310 {
 311         int ret=-1;
 312         DEBUGQUE("canque_sync_wait_kern\n");
 313         wait_event_interruptible((qends->endinfo.fileinfo.emptyq),
 314                 (ret=canque_fifo_test_fl(&qedge->fifo,EMPTY)?1:0));
 315         return ret;
 316 }
 317
 318
 319 /**
 320  * canque_fifo_init_kern - initialize one CAN FIFO
 321  * @fifo: pointer to the FIFO structure
 322  * @slotsnr: number of requested slots
 323  *
 324  * Return Value: The negative value indicates, that there is no memory
 325  *      to allocate space for the requested number of the slots.
 326  */
 327 int canque_fifo_init_kern(struct canque_fifo_t *fifo, int slotsnr)
 328 {
 329         int size;
 330         if(!slotsnr) slotsnr=MAX_BUF_LENGTH;
 331         size=sizeof(struct canque_slot_t)*slotsnr;
 332         fifo->entry=kmalloc(size,GFP_KERNEL);
 333         if(!fifo->entry) return -1;
 334         fifo->slotsnr=slotsnr;
 335         return canque_fifo_init_slots(fifo);
 336 }
 337
 338 /**
 339  * canque_fifo_done_kern - frees slots allocated for CAN FIFO
 340  * @fifo: pointer to the FIFO structure
 341  */
 342 int canque_fifo_done_kern(struct canque_fifo_t *fifo)
 343 {
 344         if(fifo->entry)
 345                 kfree(fifo->entry);
 346         fifo->entry=NULL;
 347         return 1;
 348 }
 349
 350
 351 /**
 352  * canque_new_edge_kern - allocate new edge structure in the Linux kernel context
 353  * @slotsnr: required number of slots in the newly allocated edge structure
 354  *
 355  * Return Value: Returns pointer to allocated slot structure or %NULL if
 356  *      there is not enough memory to process operation.
 357  */
 358 struct canque_edge_t *canque_new_edge_kern(int slotsnr)
 359 {
 360         struct canque_edge_t *qedge;
 361         qedge = (struct canque_edge_t *)kmalloc(sizeof(struct canque_edge_t), GFP_KERNEL);
 362         if(qedge == NULL) return NULL;
 363
 364         memset(qedge,0,sizeof(struct canque_edge_t));
 365         can_spin_lock_init(&qedge->fifo.fifo_lock);
 366         if(canque_fifo_init_kern(&qedge->fifo, slotsnr)<0){
 367                 kfree(qedge);
 368                 DEBUGQUE("canque_new_edge_kern failed\n");
 369                 return NULL;
 370         }
 371         atomic_set(&qedge->edge_used,1);
 372         qedge->filtid = 0;
 373         qedge->filtmask = canque_filtid2internal(0l, (processlocal<2)? MSG_LOCAL:0);
 374         qedge->edge_prio = 0;
 375     #ifdef CAN_DEBUG
 376         /* not exactly clean, but enough for debugging */
 377         atomic_inc(&edge_num_cnt);
 378         qedge->edge_num=atomic_read(&edge_num_cnt);
 379     #endif /* CAN_DEBUG */
 380         DEBUGQUE("canque_new_edge_kern %d\n",qedge->edge_num);
 381         return qedge;
 382 }
 383
 384 #ifdef USE_SYNC_DISCONNECT_EDGE_KERN
 385
 386 /*not included in doc
 387  * canqueue_disconnect_edge_kern - disconnect edge from communicating entities with wait
 388  * @qends: ends structure belonging to calling communication object
 389  * @qedge: pointer to edge
 390  *
 391  * Same as canqueue_disconnect_edge(), but tries to wait for state with zero
 392  * use counter.
 393  * Return Value: Negative value means, that edge is used and cannot
 394  *      be disconnected yet. Operation has to be delayed.
 395  */
 396 int canqueue_disconnect_edge_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge)
 397 {
 398         canque_fifo_set_fl(&qedge->fifo,BLOCK);
 399         DEBUGQUE("canqueue_disconnect_edge_kern %d called\n",qedge->edge_num);
 400         if(!canque_fifo_test_and_set_fl(&qedge->fifo,DEAD)){
 401                 canque_notify_bothends(qedge, CANQUEUE_NOTIFY_DEAD);
 402
 403                 if(atomic_read(&qedge->edge_used)>0)
 404                         atomic_dec(&qedge->edge_used);
 405
 406                 DEBUGQUE("canqueue_disconnect_edge_kern %d waiting\n",qedge->edge_num);
 407                 wait_event((qends->endinfo.fileinfo.emptyq),
 408                         (canqueue_disconnect_edge(qedge)>=0));
 409
 410                 /*set_current_state(TASK_UNINTERRUPTIBLE);*/
 411                 /*schedule_timeout(HZ);*/
 412                 return 0;
 413         } else {
 414                 DEBUGQUE("canqueue_disconnect_edge_kern cannot set DEAD\n");
 415                 return -1;
 416         }
 417 }
 418
 419
 420 int canqueue_disconnect_list_kern(struct canque_ends_t *qends, struct list_head *list)
 421 {
 422         struct canque_edge_t *edge;
 423         can_spin_irqflags_t flags;
 424         for(;;){
 425                 can_spin_lock_irqsave(&qends->ends_lock,flags);
 426                 if(list_empty(list)){
 427                         can_spin_unlock_irqrestore(&qends->ends_lock,flags);
 428                         return 0;
 429                 }
 430                 if(list == &qends->inlist)
 431                         edge=list_entry(list->next,struct canque_edge_t,inpeers);
 432                 else
 433                         edge=list_entry(list->next,struct canque_edge_t,outpeers);
 434                 atomic_inc(&edge->edge_used);
 435                 can_spin_unlock_irqrestore(&qends->ends_lock,flags);
 436                 if(canqueue_disconnect_edge_kern(qends, edge)>=0) {
 437                         /* Free edge memory */
 438                         canque_fifo_done_kern(&edge->fifo);
 439                         kfree(edge);
 440                 }else{
 441                         canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
 442                         canque_edge_decref(edge);
 443                         DEBUGQUE("canqueue_disconnect_list_kern in troubles\n");
 444                         DEBUGQUE("the edge %d has usage count %d and flags %ld\n",edge->edge_num,atomic_read(&edge->edge_used),edge->fifo.fifo_flags);
 445                         return -1;
 446                 }
 447         }
 448 }
 449
 450 #endif /*USE_SYNC_DISCONNECT_EDGE_KERN*/
 451
 452
 453 int canqueue_ends_sync_all_kern(struct canque_ends_t *qends)
 454 {
 455         struct canque_edge_t *qedge;
 456
 457         canque_for_each_inedge(qends, qedge){
 458                 DEBUGQUE("canque_sync_wait_kern called for edge %d\n",qedge->edge_num);
 459                 canque_sync_wait_kern(qends, qedge);
 460         }
 461         return 0;
 462 }
 463
 464
 465 void canqueue_ends_dispose_postpone(struct canque_ends_t *qends)
 466 {
 467         can_spin_irqflags_t flags;
 468
 469         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
 470         qends->ends_flags |= CAN_ENDSF_DEAD;
 471         list_add(&qends->dead_peers,&canque_dead_ends);
 472         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 473         canque_dead_tasklet_schedule();
 474 }
 475
 476
 477 /**
 478  * canqueue_ends_dispose_kern - finalizing of the ends structure for Linux kernel clients
 479  * @qends: pointer to ends structure
 480  * @sync: flag indicating, that user wants to wait for processing of all remaining
 481  *      messages
 482  *
 483  * Return Value: Function should be designed such way to not fail.
 484  */
 485 int canqueue_ends_dispose_kern(struct canque_ends_t *qends, int sync)
 486 {
 487         int delayed;
 488
 489         DEBUGQUE("canqueue_ends_dispose_kern\n");
 490         canqueue_block_inlist(qends);
 491         canqueue_block_outlist(qends);
 492
 493         /*Wait for sending of all pending messages in the output FIFOs*/
 494         if(sync)
 495                 canqueue_ends_sync_all_kern(qends);
 496
 497         /* Finish or kill all outgoing edges listed in inends */
 498         delayed=canqueue_ends_kill_inlist(qends, 1);
 499         /* Kill all incoming edges listed in outends */
 500         delayed|=canqueue_ends_kill_outlist(qends);
 501
 502         wake_up(&qends->endinfo.fileinfo.readq);
 503         wake_up(&qends->endinfo.fileinfo.writeq);
 504         wake_up(&qends->endinfo.fileinfo.emptyq);
 505
 506         if(delayed){
 507                 canqueue_ends_dispose_postpone(qends);
 508
 509                 DEBUGQUE("canqueue_ends_dispose_kern delayed\n");
 510                 return 1;
 511         }
 512
 513         kfree(qends);
 514         DEBUGQUE("canqueue_ends_dispose_kern finished\n");
 515         return 0;
 516 }
 517
 518 void canqueue_kern_initialize()
 519 {
 520         can_spin_lock_init(&canque_dead_func_lock);
 521 }