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-0.3  17 Jun 2004
   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)
 126 {
 127         can_spin_irqflags_t flags;
 128
 129         canque_notify_bothends(edge,CANQUEUE_NOTIFY_NOUSR);
 130     #ifdef CAN_WITH_RTL
 131         /* The problem of the above call is, that in RT-Linux to Linux notify
 132            case is edge scheduled for delayed notify delivery, this needs
 133            to be reflected there */
 134         if(atomic_read(&edge->edge_used)>0){
 135                 can_spin_lock_irqsave(&edge->inends->ends_lock, flags);
 136                 can_spin_lock(&edge->outends->ends_lock);
 137                 if(atomic_read(&edge->edge_used)>0){
 138                         /* left edge to live for a while, banshee comes again in a while */
 139                         canque_fifo_clear_fl(&edge->fifo,DEAD);
 140                         can_spin_unlock(&edge->outends->ends_lock);
 141                         can_spin_unlock_irqrestore(&edge->inends->ends_lock, flags);
 142                         can_printk(KERN_ERR "can_quertl (debug): canque_edge_do_dead postponed\n");
 143                         return;
 144                 }
 145                 can_spin_unlock(&edge->outends->ends_lock);
 146                 can_spin_unlock_irqrestore(&edge->inends->ends_lock, flags);
 147         }
 148     #endif /*CAN_WITH_RTL*/
 149
 150         if(canqueue_disconnect_edge(edge)<0){
 151                 ERRMSGQUE("canque_edge_do_dead: canqueue_disconnect_edge failed !!!\n");
 152                 return;
 153         }
 154
 155         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
 156         list_add(&edge->inpeers,&canque_dead_edges);
 157         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 158         canque_dead_tasklet_schedule();
 159 }
 160
 161
 162
 163 /*if(qends->ends_flags & CAN_ENDSF_DEAD){
 164         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
 165         list_del(&qends->dead_peers);
 166         list_add(&qends->dead_peers,&canque_dead_ends);
 167         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 168         tasklet_schedule(&canque_dead_tl);
 169 }*/
 170
 171
 172 /**
 173  * canqueue_notify_kern - notification callback handler for Linux userspace clients
 174  * @qends: pointer to the callback side ends structure
 175  * @qedge: edge which invoked notification
 176  * @what: notification type
 177  *
 178  * The notification event is handled directly by call of this function except case,
 179  * when called from RT-Linux context in mixed mode Linux/RT-Linux compilation.
 180  * It is not possible to directly call Linux kernel synchronization primitives
 181  * in such case. The notification request is postponed and signaled by @pending_inops flags
 182  * by call canqueue_rtl2lin_check_and_pend() function.
 183  * The edge reference count is increased until until all pending notifications are processed.
 184  */
 185 void canqueue_notify_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge, int what)
 186 {
 187         DEBUGQUE("canqueue_notify_kern for edge %d, use %d and event %d\n",
 188                         qedge->edge_num,(int)atomic_read(&qedge->edge_used),what);
 189
 190         /* delay event delivery for RT-Linux -> kernel notifications */
 191         if(canqueue_rtl2lin_check_and_pend(qends,qedge,what)){
 192                 DEBUGQUE("canqueue_notify_kern postponed\n");
 193                 return;
 194         }
 195
 196         switch(what){
 197                 case CANQUEUE_NOTIFY_EMPTY:
 198                         wake_up(&qends->endinfo.fileinfo.emptyq);
 199                         if(canque_fifo_test_and_clear_fl(&qedge->fifo, FREEONEMPTY))
 200                                 canque_edge_decref(qedge);
 201                         break;
 202                 case CANQUEUE_NOTIFY_SPACE:
 203                         wake_up(&qends->endinfo.fileinfo.writeq);
 204                     #ifdef CAN_ENABLE_KERN_FASYNC
 205                         /* Asynchronous I/O processing */
 206                         kill_fasync(&qends->endinfo.fileinfo.fasync, SIGIO, POLL_OUT);
 207                     #endif /*CAN_ENABLE_KERN_FASYNC*/
 208                         break;
 209                 case CANQUEUE_NOTIFY_PROC:
 210                         wake_up(&qends->endinfo.fileinfo.readq);
 211                     #ifdef CAN_ENABLE_KERN_FASYNC
 212                         /* Asynchronous I/O processing */
 213                         kill_fasync(&qends->endinfo.fileinfo.fasync, SIGIO, POLL_IN);
 214                     #endif /*CAN_ENABLE_KERN_FASYNC*/
 215                         break;
 216                 case CANQUEUE_NOTIFY_NOUSR:
 217                         wake_up(&qends->endinfo.fileinfo.readq);
 218                         wake_up(&qends->endinfo.fileinfo.writeq);
 219                         wake_up(&qends->endinfo.fileinfo.emptyq);
 220                         break;
 221                 case CANQUEUE_NOTIFY_DEAD_WANTED:
 222                 case CANQUEUE_NOTIFY_DEAD:
 223                         if(canque_fifo_test_and_clear_fl(&qedge->fifo, READY))
 224                                 canque_edge_decref(qedge);
 225                         break;
 226                 case CANQUEUE_NOTIFY_ATTACH:
 227                         break;
 228         }
 229 }
 230
 231 /**
 232  * canqueue_ends_init_kern - Linux userspace clients specific ends initialization
 233  * @qends: pointer to the callback side ends structure
 234  */
 235 int canqueue_ends_init_kern(struct canque_ends_t *qends)
 236 {
 237         canqueue_ends_init_gen(qends);
 238         qends->context=NULL;
 239         init_waitqueue_head(&qends->endinfo.fileinfo.readq);
 240         init_waitqueue_head(&qends->endinfo.fileinfo.writeq);
 241         init_waitqueue_head(&qends->endinfo.fileinfo.emptyq);
 242     #ifdef CAN_ENABLE_KERN_FASYNC
 243         qends->endinfo.fileinfo.fasync=NULL;
 244     #endif /*CAN_ENABLE_KERN_FASYNC*/
 245
 246         qends->notify=canqueue_notify_kern;
 247         DEBUGQUE("canqueue_ends_init_kern\n");
 248         return 0;
 249 }
 250
 251
 252 /**
 253  * canque_get_inslot4id_wait_kern - find or wait for best outgoing edge and slot for given ID
 254  * @qends: ends structure belonging to calling communication object
 255  * @qedgep: place to store pointer to found edge
 256  * @slotp: place to store pointer to  allocated slot
 257  * @cmd: command type for slot
 258  * @id: communication ID of message to send into edge
 259  * @prio: optional priority of message
 260  *
 261  * Same as canque_get_inslot4id(), except, that it waits for free slot
 262  * in case, that queue is full. Function is specific for Linux userspace clients.
 263  * Return Value: If there is no usable edge negative value is returned.
 264  */
 265 int canque_get_inslot4id_wait_kern(struct canque_ends_t *qends,
 266         struct canque_edge_t **qedgep, struct canque_slot_t **slotp,
 267         int cmd, unsigned long id, int prio)
 268 {
 269         int ret=-1;
 270         DEBUGQUE("canque_get_inslot4id_wait_kern for cmd %d, id %ld, prio %d\n",cmd,id,prio);
 271         wait_event_interruptible((qends->endinfo.fileinfo.writeq),
 272                 (ret=canque_get_inslot4id(qends,qedgep,slotp,cmd,id,prio))!=-1);
 273         return ret;
 274 }
 275
 276 /**
 277  * canque_get_outslot_wait_kern - receive or wait for ready slot for given ends
 278  * @qends: ends structure belonging to calling communication object
 279  * @qedgep: place to store pointer to found edge
 280  * @slotp: place to store pointer to received slot
 281  *
 282  * The same as canque_test_outslot(), except it waits in the case, that there is
 283  * no ready slot for given ends. Function is specific for Linux userspace clients.
 284  * Return Value: Negative value informs, that there is no ready output
 285  *      slot for given ends. Positive value is equal to the command
 286  *      slot has been allocated by the input side.
 287  */
 288 int canque_get_outslot_wait_kern(struct canque_ends_t *qends,
 289         struct canque_edge_t **qedgep, struct canque_slot_t **slotp)
 290 {
 291         int ret=-1;
 292         DEBUGQUE("canque_get_outslot_wait_kern\n");
 293         wait_event_interruptible((qends->endinfo.fileinfo.readq),
 294                 (ret=canque_test_outslot(qends,qedgep,slotp))!=-1);
 295         return ret;
 296 }
 297
 298 /**
 299  * canque_sync_wait_kern - wait for all slots processing
 300  * @qends: ends structure belonging to calling communication object
 301  * @qedge: pointer to edge
 302  *
 303  * Functions waits for ends transition into empty state.
 304  * Return Value: Positive value indicates, that edge empty state has been reached.
 305  *      Negative or zero value informs about interrupted wait or other problem.
 306  */
 307 int canque_sync_wait_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge)
 308 {
 309         int ret=-1;
 310         DEBUGQUE("canque_sync_wait_kern\n");
 311         wait_event_interruptible((qends->endinfo.fileinfo.emptyq),
 312                 (ret=canque_fifo_test_fl(&qedge->fifo,EMPTY)?1:0));
 313         return ret;
 314 }
 315
 316
 317 /**
 318  * canque_fifo_init_kern - initialize one CAN FIFO
 319  * @fifo: pointer to the FIFO structure
 320  * @slotsnr: number of requested slots
 321  *
 322  * Return Value: The negative value indicates, that there is no memory
 323  *      to allocate space for the requested number of the slots.
 324  */
 325 int canque_fifo_init_kern(struct canque_fifo_t *fifo, int slotsnr)
 326 {
 327         int size;
 328         if(!slotsnr) slotsnr=MAX_BUF_LENGTH;
 329         size=sizeof(struct canque_slot_t)*slotsnr;
 330         fifo->entry=kmalloc(size,GFP_KERNEL);
 331         if(!fifo->entry) return -1;
 332         fifo->slotsnr=slotsnr;
 333         return canque_fifo_init_slots(fifo);
 334 }
 335
 336 /**
 337  * canque_fifo_done_kern - frees slots allocated for CAN FIFO
 338  * @fifo: pointer to the FIFO structure
 339  */
 340 int canque_fifo_done_kern(struct canque_fifo_t *fifo)
 341 {
 342         if(fifo->entry)
 343                 kfree(fifo->entry);
 344         fifo->entry=NULL;
 345         return 1;
 346 }
 347
 348
 349 /**
 350  * canque_new_edge_kern - allocate new edge structure in the Linux kernel context
 351  * @slotsnr: required number of slots in the newly allocated edge structure
 352  *
 353  * Return Value: Returns pointer to allocated slot structure or %NULL if
 354  *      there is not enough memory to process operation.
 355  */
 356 struct canque_edge_t *canque_new_edge_kern(int slotsnr)
 357 {
 358         struct canque_edge_t *qedge;
 359         qedge = (struct canque_edge_t *)kmalloc(sizeof(struct canque_edge_t), GFP_KERNEL);
 360         if(qedge == NULL) return NULL;
 361
 362         memset(qedge,0,sizeof(struct canque_edge_t));
 363         can_spin_lock_init(&qedge->fifo.fifo_lock);
 364         if(canque_fifo_init_kern(&qedge->fifo, slotsnr)<0){
 365                 kfree(qedge);
 366                 DEBUGQUE("canque_new_edge_kern failed\n");
 367                 return NULL;
 368         }
 369         atomic_set(&qedge->edge_used,1);
 370         qedge->filtid = 0;
 371         qedge->filtmask = canque_filtid2internal(0l, (processlocal<2)? MSG_LOCAL:0);
 372         qedge->edge_prio = 0;
 373     #ifdef CAN_DEBUG
 374         /* not exactly clean, but enough for debugging */
 375         atomic_inc(&edge_num_cnt);
 376         qedge->edge_num=atomic_read(&edge_num_cnt);
 377     #endif /* CAN_DEBUG */
 378         DEBUGQUE("canque_new_edge_kern %d\n",qedge->edge_num);
 379         return qedge;
 380 }
 381
 382 #ifdef USE_SYNC_DISCONNECT_EDGE_KERN
 383
 384 /*not included in doc
 385  * canqueue_disconnect_edge_kern - disconnect edge from communicating entities with wait
 386  * @qends: ends structure belonging to calling communication object
 387  * @qedge: pointer to edge
 388  *
 389  * Same as canqueue_disconnect_edge(), but tries to wait for state with zero
 390  * use counter.
 391  * Return Value: Negative value means, that edge is used and cannot
 392  *      be disconnected yet. Operation has to be delayed.
 393  */
 394 int canqueue_disconnect_edge_kern(struct canque_ends_t *qends, struct canque_edge_t *qedge)
 395 {
 396         canque_fifo_set_fl(&qedge->fifo,BLOCK);
 397         DEBUGQUE("canqueue_disconnect_edge_kern %d called\n",qedge->edge_num);
 398         if(!canque_fifo_test_and_set_fl(&qedge->fifo,DEAD)){
 399                 canque_notify_bothends(qedge, CANQUEUE_NOTIFY_DEAD);
 400
 401                 if(atomic_read(&qedge->edge_used)>0)
 402                         atomic_dec(&qedge->edge_used);
 403
 404                 DEBUGQUE("canqueue_disconnect_edge_kern %d waiting\n",qedge->edge_num);
 405                 wait_event((qends->endinfo.fileinfo.emptyq),
 406                         (canqueue_disconnect_edge(qedge)>=0));
 407
 408                 /*set_current_state(TASK_UNINTERRUPTIBLE);*/
 409                 /*schedule_timeout(HZ);*/
 410                 return 0;
 411         } else {
 412                 DEBUGQUE("canqueue_disconnect_edge_kern cannot set DEAD\n");
 413                 return -1;
 414         }
 415 }
 416
 417
 418 int canqueue_disconnect_list_kern(struct canque_ends_t *qends, struct list_head *list)
 419 {
 420         struct canque_edge_t *edge;
 421         can_spin_irqflags_t flags;
 422         for(;;){
 423                 can_spin_lock_irqsave(&qends->ends_lock,flags);
 424                 if(list_empty(list)){
 425                         can_spin_unlock_irqrestore(&qends->ends_lock,flags);
 426                         return 0;
 427                 }
 428                 if(list == &qends->inlist)
 429                         edge=list_entry(list->next,struct canque_edge_t,inpeers);
 430                 else
 431                         edge=list_entry(list->next,struct canque_edge_t,outpeers);
 432                 atomic_inc(&edge->edge_used);
 433                 can_spin_unlock_irqrestore(&qends->ends_lock,flags);
 434                 if(canqueue_disconnect_edge_kern(qends, edge)>=0) {
 435                         /* Free edge memory */
 436                         canque_fifo_done_kern(&edge->fifo);
 437                         kfree(edge);
 438                 }else{
 439                         canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
 440                         canque_edge_decref(edge);
 441                         DEBUGQUE("canqueue_disconnect_list_kern in troubles\n");
 442                         DEBUGQUE("the edge %d has usage count %d and flags %ld\n",edge->edge_num,atomic_read(&edge->edge_used),edge->fifo.fifo_flags);
 443                         return -1;
 444                 }
 445         }
 446 }
 447
 448 #endif /*USE_SYNC_DISCONNECT_EDGE_KERN*/
 449
 450
 451 int canqueue_ends_sync_all_kern(struct canque_ends_t *qends)
 452 {
 453         struct canque_edge_t *qedge;
 454
 455         canque_for_each_inedge(qends, qedge){
 456                 DEBUGQUE("canque_sync_wait_kern called for edge %d\n",qedge->edge_num);
 457                 canque_sync_wait_kern(qends, qedge);
 458         }
 459         return 0;
 460 }
 461
 462
 463 void canqueue_ends_dispose_postpone(struct canque_ends_t *qends)
 464 {
 465         can_spin_irqflags_t flags;
 466
 467         can_spin_lock_irqsave(&canque_dead_func_lock, flags);
 468         qends->ends_flags |= CAN_ENDSF_DEAD;
 469         list_add(&qends->dead_peers,&canque_dead_ends);
 470         can_spin_unlock_irqrestore(&canque_dead_func_lock, flags);
 471         canque_dead_tasklet_schedule();
 472 }
 473
 474
 475 /**
 476  * canqueue_ends_dispose_kern - finalizing of the ends structure for Linux kernel clients
 477  * @qends: pointer to ends structure
 478  * @sync: flag indicating, that user wants to wait for processing of all remaining
 479  *      messages
 480  *
 481  * Return Value: Function should be designed such way to not fail.
 482  */
 483 int canqueue_ends_dispose_kern(struct canque_ends_t *qends, int sync)
 484 {
 485         int delayed;
 486
 487         DEBUGQUE("canqueue_ends_dispose_kern\n");
 488         canqueue_block_inlist(qends);
 489         canqueue_block_outlist(qends);
 490
 491         /*Wait for sending of all pending messages in the output FIFOs*/
 492         if(sync)
 493                 canqueue_ends_sync_all_kern(qends);
 494
 495         /* Finish or kill all outgoing edges listed in inends */
 496         delayed=canqueue_ends_kill_inlist(qends, 1);
 497         /* Kill all incoming edges listed in outends */
 498         delayed|=canqueue_ends_kill_outlist(qends);
 499
 500         wake_up(&qends->endinfo.fileinfo.readq);
 501         wake_up(&qends->endinfo.fileinfo.writeq);
 502         wake_up(&qends->endinfo.fileinfo.emptyq);
 503
 504         if(delayed){
 505                 canqueue_ends_dispose_postpone(qends);
 506
 507                 DEBUGQUE("canqueue_ends_dispose_kern delayed\n");
 508                 return 1;
 509         }
 510
 511         kfree(qends);
 512         DEBUGQUE("canqueue_ends_dispose_kern finished\n");
 513         return 0;
 514 }
 515
 516 void canqueue_kern_initialize()
 517 {
 518         can_spin_lock_init(&canque_dead_func_lock);
 519 }