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