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 <linux/autoconf.h>
  11
  12 #include <linux/version.h>
  13 #include <linux/poll.h>
  14
  15 #include "../include/main.h"
  16 #include "../include/select.h"
  17
  18 unsigned int can_poll(struct file *file, poll_table *wait)
  19 {
  20         struct canuser_t *canuser = (struct canuser_t*)(file->private_data);
  21         struct canque_ends_t *qends;
  22         struct msgobj_t *obj;
  23         unsigned int mask = 0;
  24         unsigned long flags;
  25         struct canque_edge_t *edge;
  26         struct list_head *entry;
  27         int full=0;
  28         int i;
  29
  30         if(!canuser || (canuser->magic != CAN_USER_MAGIC)){
  31                 CANMSG("can_close: bad canuser magic\n");
  32                 return -ENODEV;
  33         }
  34
  35         obj = canuser->msgobj;
  36         qends = canuser->qends;
  37
  38         if (file->f_mode & FMODE_READ) {
  39                 poll_wait(file, &qends->endinfo.fileinfo.readq, wait);
  40                 for(i=CANQUEUE_PRIO_NR;--i>=0;) {
  41                         if(!list_empty(&qends->active[i]))
  42                                 mask |= POLLIN | POLLRDNORM;
  43                 }
  44         }
  45
  46         if ((file->f_mode & FMODE_WRITE) && !(file->f_flags & O_SYNC)) {
  47                 poll_wait(file, &qends->endinfo.fileinfo.writeq, wait);
  48
  49                 spin_lock_irqsave(&qends->ends_lock, flags);
  50                 list_for_each(entry,&qends->inlist){
  51                         edge=list_entry(entry,struct canque_edge_t,inpeers);
  52                         if(canque_fifo_test_fl(&edge->fifo,FULL))
  53                                 full=1;
  54                 }
  55                 spin_unlock_irqrestore(&qends->ends_lock, flags);
  56
  57                 if(!full)
  58                         mask |= POLLOUT | POLLWRNORM;
  59         }
  60
  61         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_SYNC)) {
  62                 poll_wait(file, &qends->endinfo.fileinfo.emptyq, wait);
  63
  64                 spin_lock_irqsave(&qends->ends_lock, flags);
  65                 list_for_each(entry,&qends->inlist){
  66                         edge=list_entry(entry,struct canque_edge_t,inpeers);
  67                         if(!canque_fifo_test_fl(&edge->fifo,EMPTY))
  68                                 full=1;
  69                 }
  70                 spin_unlock_irqrestore(&qends->ends_lock, flags);
  71
  72                 if(!full)
  73                         mask |= POLLOUT | POLLWRNORM;
  74         }
  75         return mask;
  76 }