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-0.3  17 Jun 2004
   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
  51         /* Automatic selection of extended format if ID>2047 */
  52         if (msg_buff->id & ~0x7ffl & MSG_ID_MASK ) msg_flags |= MSG_EXT;
  53         /* has been dependent on "extended" option */
  54
  55         /* If the output buffer is full, return immediately in case O_NONBLOCK
  56          * has been specified or loop until space becomes available.
  57          */
  58         if ((ret=canque_get_inslot4id(qends, &qedge, &slot,
  59                         0, msg_buff->id, 0))<0){
  60                 DEBUGMSG("Buffer is full\n");
  61                 if(ret < -1)
  62                         return -EIO;
  63
  64                 if (fptr->f_flags & O_NONBLOCK)
  65                         return -EAGAIN;
  66
  67                 ret=canque_get_inslot4id_wait_rtl(qends, &qedge, &slot,
  68                                                 0, msg_buff->id, 0);
  69                 if (ret == -1)
  70                         return -EINTR;
  71
  72                 if(ret<0) {
  73                         return -EIO;
  74                 }
  75         }
  76         slot->msg=*(msg_buff++);
  77         slot->msg.flags=msg_flags;
  78         canque_put_inslot(qends, qedge, slot);
  79         bytes_to_copy = length-sizeof(struct canmsg_t);
  80
  81         /*
  82          * Try to send more messages
  83          */
  84         while (bytes_to_copy >= sizeof(struct canmsg_t)) {
  85                 bytes_to_copy -= sizeof(struct canmsg_t);
  86                 msg_flags=msg_buff->flags;
  87
  88                 /* Automatic selection of extended format if ID>2047 */
  89                 if (msg_buff->id & ~0x7ffl & MSG_ID_MASK ) msg_flags |= MSG_EXT;
  90                 /* has been dependent on "extended" option */
  91
  92                 /* Get slot */
  93                 if(canque_get_inslot4id(qends, &qedge, &slot,
  94                         0, msg_buff->id, 0) < 0) break;
  95                 slot->msg=*(msg_buff++);
  96                 slot->msg.flags=msg_flags;
  97                 canque_put_inslot(qends, qedge, slot);
  98         }
  99
 100         if(fptr->f_flags & O_SYNC) {
 101                 canque_sync_wait_rtl(qends, qedge);
 102         }
 103         return length-bytes_to_copy;
 104 }
 105
 106 #endif /*CAN_WITH_RTL*/