lincan/src/select.c

   1 /* select.c
   2  * Header file for the Linux CAN-bus driver.
   3  * Written by Arnaud Westenberg email:arnaud@wanadoo.nl
   4  * Added by Pavel Pisa - OCERA team member
   5  * email:pisa@cmp.felk.cvut.cz
   6  * This software is released under the GPL-License.
   7  * Version lincan-0.2  9 Jul 2003
   8  */
   9
  10 #include "../include/can.h"
  11 #include "../include/can_sysdep.h"
  12 #include "../include/main.h"
  13
  14 #include <linux/poll.h>
  15 #include "../include/select.h"
  16
  17 unsigned int can_poll(struct file *file, poll_table *wait)
  18 {
  19         struct canuser_t *canuser = (struct canuser_t*)(file->private_data);
  20         struct canque_ends_t *qends;
  21         struct msgobj_t *obj;
  22         unsigned int mask = 0;
  23         unsigned long flags;
  24         struct canque_edge_t *edge;
  25         struct list_head *entry;
  26         int full=0;
  27         int i;
  28
  29         if(!canuser || (canuser->magic != CAN_USER_MAGIC)){
  30                 CANMSG("can_close: bad canuser magic\n");
  31                 return -ENODEV;
  32         }
  33
  34         obj = canuser->msgobj;
  35         qends = canuser->qends;
  36
  37         if (file->f_mode & FMODE_READ) {
  38                 poll_wait(file, &qends->endinfo.fileinfo.readq, wait);
  39                 for(i=CANQUEUE_PRIO_NR;--i>=0;) {
  40                         if(!list_empty(&qends->active[i]))
  41                                 mask |= POLLIN | POLLRDNORM;
  42                 }
  43         }
  44
  45         if ((file->f_mode & FMODE_WRITE) && !(file->f_flags & O_SYNC)) {
  46                 poll_wait(file, &qends->endinfo.fileinfo.writeq, wait);
  47
  48                 spin_lock_irqsave(&qends->ends_lock, flags);
  49                 list_for_each(entry,&qends->inlist){
  50                         edge=list_entry(entry,struct canque_edge_t,inpeers);
  51                         if(canque_fifo_test_fl(&edge->fifo,FULL))
  52                                 full=1;
  53                 }
  54                 spin_unlock_irqrestore(&qends->ends_lock, flags);
  55
  56                 if(!full)
  57                         mask |= POLLOUT | POLLWRNORM;
  58         }
  59
  60         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_SYNC)) {
  61                 poll_wait(file, &qends->endinfo.fileinfo.emptyq, wait);
  62
  63                 spin_lock_irqsave(&qends->ends_lock, flags);
  64                 list_for_each(entry,&qends->inlist){
  65                         edge=list_entry(entry,struct canque_edge_t,inpeers);
  66                         if(!canque_fifo_test_fl(&edge->fifo,EMPTY))
  67                                 full=1;
  68                 }
  69                 spin_unlock_irqrestore(&qends->ends_lock, flags);
  70
  71                 if(!full)
  72                         mask |= POLLOUT | POLLWRNORM;
  73         }
  74         return mask;
  75 }