lincan/src/write_rtl.c

   1 /* write.c
   2  * Linux CAN-bus device driver.
   3  * Written by Arnaud Westenberg email:arnaud@wanadoo.nl
   4  * Rewritten for new CAN queues 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 #ifdef CAN_WITH_RTL
  11
  12 #include "../include/can.h"
  13 #include "../include/can_sysdep.h"
  14 #include "../include/main.h"
  15
  16 #include <rtl_posixio.h>
  17 #include "../include/can_iortl.h"
  18
  19 ssize_t can_write_rtl_posix(struct rtl_file *fptr, const char *buffer,
  20                                  size_t length, loff_t *ppos)
  21 {
  22         struct canuser_t *canuser =
  23                 (struct canuser_t *)can_get_rtl_file_private_data(fptr);
  24         const struct canmsg_t *msg_buff = (struct canmsg_t *)buffer;
  25         struct canque_ends_t *qends;
  26         struct canque_edge_t *qedge;
  27         struct canque_slot_t *slot;
  28         int      msg_flags;
  29         int      ret;
  30         size_t   bytes_to_copy;
  31
  32         if(!canuser || (canuser->magic != CAN_USER_MAGIC)){
  33                 CANMSG("can_write_rtl_posix: bad canuser magic\n");
  34                 return -ENODEV;
  35         }
  36
  37         if (length < sizeof(struct canmsg_t)) {
  38                 DEBUGMSG("Trying to write less bytes than a CAN message,\n");
  39                 DEBUGMSG("this will always return 0 !\n");
  40                 return 0;
  41         }
  42         if (length > INT_MAX) {
  43                 CANMSG("Trying to write more than is supported.\n");
  44                 return -1;
  45         }
  46
  47         qends = canuser->qends;
  48
  49         msg_flags=msg_buff->flags;
  50         /* Automatic selection of extended format if "extended" set and ID>2047 */
  51         if (extended) if (msg_buff->id & ~0x7ffl ) msg_flags |= MSG_EXT;
  52
  53         /* If the output buffer is full, return immediately in case O_NONBLOCK
  54          * has been specified or loop until space becomes available.
  55          */
  56         if ((ret=canque_get_inslot4id(qends, &qedge, &slot,
  57                         0, msg_buff->id, 0))<0){
  58                 DEBUGMSG("Buffer is full\n");
  59                 if(ret < -1)
  60                         return -EIO;
  61
  62                 if (fptr->f_flags & O_NONBLOCK)
  63                         return -EAGAIN;
  64
  65                 ret=canque_get_inslot4id_wait_rtl(qends, &qedge, &slot,
  66                                                 0, msg_buff->id, 0);
  67                 if (ret == -1)
  68                         return -EINTR;
  69
  70                 if(ret<0) {
  71                         return -EIO;
  72                 }
  73         }
  74         slot->msg=*(msg_buff++);
  75         slot->msg.flags=msg_flags;
  76         canque_put_inslot(qends, qedge, slot);
  77         bytes_to_copy = length-sizeof(struct canmsg_t);
  78
  79         /*
  80          * Try to send more messages
  81          */
  82         while (bytes_to_copy >= sizeof(struct canmsg_t)) {
  83                 bytes_to_copy -= sizeof(struct canmsg_t);
  84                 msg_flags=msg_buff->flags;
  85                 /* Automatic selection of extended format if "extended" set and ID>2047 */
  86                 if (extended) if (msg_buff->id & ~0x7ffl ) msg_flags |= MSG_EXT;
  87                 /* Get slot */
  88                 if(canque_get_inslot4id(qends, &qedge, &slot,
  89                         0, msg_buff->id, 0) < 0) break;
  90                 slot->msg=*(msg_buff++);
  91                 slot->msg.flags=msg_flags;
  92                 canque_put_inslot(qends, qedge, slot);
  93         }
  94
  95         if(fptr->f_flags & O_SYNC) {
  96                 canque_sync_wait_rtl(qends, qedge);
  97         }
  98         return length-bytes_to_copy;
  99 }
 100
 101 #endif /*CAN_WITH_RTL*/