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         int err;
  50         /*struct canque_ends_t *qends;*/
  51
  52         DEBUGMSG("Remote transmission request\n");
  53
  54         /*qends = canuser->qends;*/
  55
  56         /* Initialize hardware pointers */
  57         obj = canuser->msgobj;
  58         if (obj == NULL) {
  59                 CANMSG("Could not assign buffer structure\n");
  60                 return -ENODEV;
  61         }
  62
  63         if ( (chip = obj->hostchip) == NULL) {
  64                 CANMSG("Device is not correctly configured,\n");
  65                 CANMSG("please reload the driver.\n");
  66                 return -ENODEV;
  67         }
  68
  69         can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
  70         if (hardware_p->rtr_queue == NULL) { //No remote messages pending
  71                 new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
  72                 if (new_rtr_entry == NULL) {
  73                         can_spin_unlock_irqrestore(&hardware_p->rtr_lock,
  74                                                                 flags);
  75                         return -ENOMEM;
  76                 }
  77                 hardware_p->rtr_queue=new_rtr_entry;
  78         }
  79         else {
  80                 rtr_current=hardware_p->rtr_queue;
  81                 while (rtr_current->next != NULL)
  82                         rtr_current=rtr_current->next;
  83                 new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
  84                 rtr_current->next=new_rtr_entry;
  85         }
  86         init_waitqueue_head(&new_rtr_entry->rtr_wq);
  87         new_rtr_entry->id = rtr_id;
  88         new_rtr_entry->ready_fl = 0;
  89         new_rtr_entry->rtr_message = rtr_msg;
  90         new_rtr_entry->next=NULL;
  91
  92         can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
  93
  94         /* Send remote transmission request */
  95         chip->chipspecops->remote_request(chip,obj);
  96         obj->ret = 0;
  97
  98         err = wait_event_interruptible(new_rtr_entry->rtr_wq, new_rtr_entry->ready_fl);
  99
 100         can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
 101         if (hardware_p->rtr_queue == new_rtr_entry) {
 102                 if (new_rtr_entry->next != NULL)
 103                         hardware_p->rtr_queue=new_rtr_entry->next;
 104                 else
 105                         hardware_p->rtr_queue=NULL;
 106         }
 107         else {
 108                 rtr_current=hardware_p->rtr_queue;
 109                 while (rtr_current->next != new_rtr_entry)
 110                         rtr_current=rtr_current->next;
 111                 if (new_rtr_entry->next != NULL)
 112                         rtr_current->next=new_rtr_entry->next;
 113                 else
 114                         rtr_current->next=NULL;
 115         }
 116         can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
 117         kfree(new_rtr_entry);
 118
 119         if (err)
 120                 return -EINTR;
 121
 122         return obj->ret;
 123 }
 124