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         struct canque_edge_t *edge;
  24         int full=0;
  25         int i;
  26
  27         if(!canuser || (canuser->magic != CAN_USER_MAGIC)){
  28                 CANMSG("can_close: bad canuser magic\n");
  29                 return -ENODEV;
  30         }
  31
  32         obj = canuser->msgobj;
  33         qends = canuser->qends;
  34
  35         if (file->f_mode & FMODE_READ) {
  36                 poll_wait(file, &qends->endinfo.fileinfo.readq, wait);
  37                 for(i=CANQUEUE_PRIO_NR;--i>=0;) {
  38                         if(!list_empty(&qends->active[i]))
  39                                 mask |= POLLIN | POLLRDNORM;
  40                 }
  41         }
  42
  43         if ((file->f_mode & FMODE_WRITE) && !(file->f_flags & O_SYNC)) {
  44                 poll_wait(file, &qends->endinfo.fileinfo.writeq, wait);
  45
  46                 canque_for_each_inedge(qends, edge) {
  47                         if(canque_fifo_test_fl(&edge->fifo,FULL))
  48                                 full=1;
  49                 }
  50
  51                 if(!full)
  52                         mask |= POLLOUT | POLLWRNORM;
  53         }
  54
  55         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_SYNC)) {
  56                 poll_wait(file, &qends->endinfo.fileinfo.emptyq, wait);
  57
  58                 canque_for_each_inedge(qends, edge) {
  59                         if(!canque_fifo_test_fl(&edge->fifo,EMPTY))
  60                                 full=1;
  61                 }
  62
  63                 if(!full)
  64                         mask |= POLLOUT | POLLWRNORM;
  65         }
  66         return mask;
  67 }