lincan/src/open.c

   1 /**************************************************************************/
   2 /* File: open.c - systemcall to open new user connection/handle           */
   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/open.h"
  39 #include "../include/setup.h"
  40
  41 #define __NO_VERSION__
  42 #include <linux/module.h>
  43
  44 int can_open(struct inode *inode, struct file *file)
  45 {
  46         struct msgobj_t *obj;
  47         struct canchip_t *chip;
  48         struct canuser_t *canuser;
  49         struct canque_ends_t *qends;
  50         struct canque_edge_t *edge;
  51         can_spin_irqflags_t iflags;
  52         char openflag;          // Martin Petera: Object already opened
  53
  54         if ( ((obj=objects_p[MINOR_NR]) == NULL) ||
  55                         ((chip=objects_p[MINOR_NR]->hostchip) == NULL) ) {
  56                 CANMSG("There is no hardware support for the device file with minor nr.: %d\n",MINOR_NR);
  57                 return -ENODEV;
  58         }
  59
  60         atomic_inc(&obj->obj_used);
  61         DEBUGMSG("Device %d opened %d times.\n", MINOR_NR, atomic_read(&obj->obj_used));
  62         openflag = can_msgobj_test_fl(obj,OPENED);      // Martin Petera: store previous status
  63         can_msgobj_set_fl(obj,OPENED);
  64
  65         if (chip->flags & CHIP_CONFIGURED)
  66                 DEBUGMSG("Device is already configured.\n");
  67         else {
  68                 if (chip->chipspecops->chip_config(chip))
  69                         CANMSG("Error configuring chip.\n");
  70                 else
  71                         chip->flags |= CHIP_CONFIGURED;
  72         } /* End of chip configuration */
  73
  74
  75         /* Martin Petera: Fix for HCAN2
  76          * pre_read was called only once -> Opening second MSG object from userspace
  77          * didn't call function to configure MSG object for receive.
  78          * FIX: Call pre_read once for each MSG object
  79          **/
  80         if (!openflag) {
  81                 if (chip->chipspecops->pre_read_config(chip,obj)<0)
  82                         CANMSG("Error initializing chip for receiving\n");
  83         }
  84
  85
  86         canuser = (struct canuser_t *)kmalloc(sizeof(struct canuser_t), GFP_KERNEL);
  87         if(canuser == NULL) goto no_canuser;
  88         canuser->flags=0;
  89         canuser->userinfo.fileinfo.file = file;
  90         canuser->msgobj = obj;
  91         canuser->magic = CAN_USER_MAGIC;
  92         file->private_data = canuser;
  93
  94         qends = (struct canque_ends_t *)kmalloc(sizeof(struct canque_ends_t), GFP_KERNEL);
  95         if(qends == NULL) goto no_qends;
  96         canqueue_ends_init_kern(qends);
  97         canuser->qends = qends;
  98
  99         /*required to synchronize with RT-Linux context*/
 100         can_spin_lock_irqsave(&canuser_manipulation_lock, iflags);
 101         list_add(&canuser->peers, &obj->obj_users);
 102         can_spin_unlock_irqrestore(&canuser_manipulation_lock, iflags);
 103
 104         if(canqueue_connect_edge(edge=canque_new_edge_kern(MAX_BUF_LENGTH),
 105                 canuser->qends, obj->qends)<0) goto no_tx_qedge;
 106
 107         if(canqueue_connect_edge(canuser->rx_edge0=canque_new_edge_kern(MAX_BUF_LENGTH),
 108                 obj->qends, canuser->qends)<0) goto no_rx_qedge;
 109         /*FIXME: more generic model should be used there*/
 110         canque_edge_decref(canuser->rx_edge0);
 111         canque_edge_decref(edge);
 112
 113 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,50))
 114         MOD_INC_USE_COUNT;
 115 #endif
 116
 117         return 0;
 118
 119     no_rx_qedge:
 120         canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
 121         canque_edge_decref(edge);
 122     no_tx_qedge:
 123         list_del(&canuser->peers);
 124         canuser->qends = NULL;
 125         canqueue_ends_dispose_kern(qends, 1);
 126
 127     no_qends:
 128         kfree(canuser);
 129
 130     no_canuser:
 131         atomic_dec(&obj->obj_used);
 132         return -ENOMEM;
 133 }