lincan/src/read_rtl.c

   1 /* read.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 /* This is the 'Normal' read handler for normal transmission messages */
  20 static inline
  21 ssize_t can_std_read_rtl(struct canque_ends_t *qends, int nonblock_fl,
  22                         char *buffer, size_t length)
  23 {
  24         int ret;
  25         struct canmsg_t *msg_buff = (struct canmsg_t *)buffer;
  26         int bytes_to_copy;
  27         struct canque_edge_t *qedge;
  28         struct canque_slot_t *slot;
  29
  30         ret=canque_test_outslot(qends, &qedge, &slot);
  31         if(ret<0){
  32                 if (nonblock_fl) {
  33                         return -EAGAIN;
  34                 }
  35                 ret=canque_get_outslot_wait_rtl(qends, &qedge, &slot);
  36                 if(ret<0){
  37                         if (ret==-1) {
  38                                 DEBUGMSG("Rx interrupted\n");
  39                                 return -EINTR;
  40                         }
  41
  42                         return -EIO;
  43                 }
  44         }
  45         *(msg_buff++)=slot->msg;
  46         canque_free_outslot(qends, qedge, slot);
  47         bytes_to_copy = length-sizeof(struct canmsg_t);
  48
  49         while (bytes_to_copy > 0) {
  50                 ret=canque_test_outslot(qends, &qedge, &slot);
  51                 if(ret<0)
  52                         break;
  53                 *(msg_buff++)=slot->msg;
  54                 canque_free_outslot(qends, qedge, slot);
  55                 bytes_to_copy -= sizeof(struct canmsg_t);
  56         }
  57
  58         return length-bytes_to_copy;
  59 }
  60
  61
  62 ssize_t can_read_rtl_posix(struct rtl_file *fptr, char *buffer,
  63                                 size_t length, loff_t *ppos)
  64 {
  65         struct canuser_t *canuser =
  66                 (struct canuser_t *)can_get_rtl_file_private_data(fptr);
  67         struct canque_ends_t *qends;
  68         int      ret;
  69
  70         if(!canuser || (canuser->magic != CAN_USER_MAGIC)){
  71                 CANMSG("can_read_rtl_posix: bad canuser magic\n");
  72                 return -ENODEV;
  73         }
  74
  75         if (length < sizeof(struct canmsg_t)) {
  76                 DEBUGMSG("Trying to read less bytes than a CAN message, \n");
  77                 DEBUGMSG("this will always return zero.\n");
  78                 return 0;
  79         }
  80
  81         qends = canuser->qends;
  82
  83         /*if (((struct canmsg_t *)buffer)->flags & MSG_RTR)
  84                 ret = can_rtr_read(chip, obj, buffer);
  85         else*/
  86                 ret = can_std_read_rtl(qends, fptr->f_flags & O_NONBLOCK,
  87                         buffer, length);
  88
  89         return ret;
  90 }
  91
  92 #endif /*CAN_WITH_RTL*/
  93