lincan/src/ioctl_remote.c

   1 /**************************************************************************/
   2 /* File: ioctl_remote.c - remote CAN messages support IOCTL systemcall    */
   3 /*                                                                        */
   4 /* LinCAN - (Not only) Linux CAN bus driver                               */
   5 /* Copyright (C) 2002-2009 DCE FEE CTU Prague <http://dce.felk.cvut.cz>   */
   6 /* Copyright (C) 2002-2009 Pavel Pisa <pisa@cmp.felk.cvut.cz>             */
   7 /* Funded by OCERA and FRESCOR IST projects                               */
   8 /* Based on CAN driver code by Arnaud Westenberg <arnaud@wanadoo.nl>      */
   9 /*                                                                        */
  10 /* LinCAN is free software; you can redistribute it and/or modify it      */
  11 /* under terms of the GNU General Public License as published by the      */
  12 /* Free Software Foundation; either version 2, or (at your option) any    */
  13 /* later version.  LinCAN is distributed in the hope that it will be      */
  14 /* useful, but WITHOUT ANY WARRANTY; without even the implied warranty    */
  15 /* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU    */
  16 /* General Public License for more details. You should have received a    */
  17 /* copy of the GNU General Public License along with LinCAN; see file     */
  18 /* COPYING. If not, write to the Free Software Foundation, 675 Mass Ave,  */
  19 /* Cambridge, MA 02139, USA.                                              */
  20 /*                                                                        */
  21 /* To allow use of LinCAN in the compact embedded systems firmware        */
  22 /* and RT-executives (RTEMS for example), main authors agree with next    */
  23 /* special exception:                                                     */
  24 /*                                                                        */
  25 /* Including LinCAN header files in a file, instantiating LinCAN generics */
  26 /* or templates, or linking other files with LinCAN objects to produce    */
  27 /* an application image/executable, does not by itself cause the          */
  28 /* resulting application image/executable to be covered by                */
  29 /* the GNU General Public License.                                        */
  30 /* This exception does not however invalidate any other reasons           */
  31 /* why the executable file might be covered by the GNU Public License.    */
  32 /* Publication of enhanced or derived LinCAN files is required although.  */
  33 /**************************************************************************/
  34
  35 #include "../include/can.h"
  36 #include "../include/can_sysdep.h"
  37 #include "../include/main.h"
  38 #include "../include/read.h"
  39 #include "../include/ioctl.h"
  40
  41 /* This is the 'RTR' read handler for remote transmission request messages */
  42 int can_ioctl_remote_read(struct canuser_t *canuser, struct canmsg_t *rtr_msg,
  43                           unsigned long rtr_id, int options)
  44 {
  45         can_spin_irqflags_t flags;
  46         struct rtr_id *rtr_current, *new_rtr_entry;
  47         struct msgobj_t *obj;
  48         struct canchip_t *chip;
  49         /*struct canque_ends_t *qends;*/
  50
  51         DEBUGMSG("Remote transmission request\n");
  52
  53         /*qends = canuser->qends;*/
  54
  55         /* Initialize hardware pointers */
  56         obj = canuser->msgobj;
  57         if (obj == NULL) {
  58                 CANMSG("Could not assign buffer structure\n");
  59                 return -ENODEV;
  60         }
  61
  62         if ( (chip = obj->hostchip) == NULL) {
  63                 CANMSG("Device is not correctly configured,\n");
  64                 CANMSG("please reload the driver.\n");
  65                 return -ENODEV;
  66         }
  67
  68         can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
  69         if (hardware_p->rtr_queue == NULL) { //No remote messages pending
  70                 new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
  71                 if (new_rtr_entry == NULL) {
  72                         can_spin_unlock_irqrestore(&hardware_p->rtr_lock,
  73                                                                 flags);
  74                         return -ENOMEM;
  75                 }
  76                 hardware_p->rtr_queue=new_rtr_entry;
  77         }
  78         else {
  79                 rtr_current=hardware_p->rtr_queue;
  80                 while (rtr_current->next != NULL)
  81                         rtr_current=rtr_current->next;
  82                 new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
  83                 rtr_current->next=new_rtr_entry;
  84         }
  85         init_waitqueue_head(&new_rtr_entry->rtr_wq);
  86         new_rtr_entry->id = rtr_id;
  87         new_rtr_entry->rtr_message = rtr_msg;
  88         new_rtr_entry->next=NULL;
  89
  90         can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
  91
  92         /* Send remote transmission request */
  93         chip->chipspecops->remote_request(chip,obj);
  94         obj->ret = 0;
  95         interruptible_sleep_on(&new_rtr_entry->rtr_wq);
  96
  97         can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
  98         if (hardware_p->rtr_queue == new_rtr_entry) {
  99                 if (new_rtr_entry->next != NULL)
 100                         hardware_p->rtr_queue=new_rtr_entry->next;
 101                 else
 102                         hardware_p->rtr_queue=NULL;
 103         }
 104         else {
 105                 rtr_current=hardware_p->rtr_queue;
 106                 while (rtr_current->next != new_rtr_entry)
 107                         rtr_current=rtr_current->next;
 108                 if (new_rtr_entry->next != NULL)
 109                         rtr_current->next=new_rtr_entry->next;
 110                 else
 111                         rtr_current->next=NULL;
 112         }
 113         can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
 114         kfree(new_rtr_entry);
 115
 116         return obj->ret;
 117 }
 118