lincan/src/open.c

   1 /* open.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 #include "../include/can.h"
  11 #include "../include/can_sysdep.h"
  12 #include "../include/main.h"
  13 #include "../include/open.h"
  14 #include "../include/setup.h"
  15
  16 #define __NO_VERSION__
  17 #include <linux/module.h>
  18
  19 int can_open(struct inode *inode, struct file *file)
  20 {
  21         struct msgobj_t *obj;
  22         struct canchip_t *chip;
  23         struct canuser_t *canuser;
  24         struct canque_ends_t *qends;
  25         struct canque_edge_t *edge;
  26         can_spin_irqflags_t iflags;
  27
  28         if ( ((obj=objects_p[MINOR_NR]) == NULL) ||
  29                         ((chip=objects_p[MINOR_NR]->hostchip) == NULL) ) {
  30                 CANMSG("There is no hardware support for the device file with minor nr.: %d\n",MINOR_NR);
  31                 return -ENODEV;
  32         }
  33
  34         atomic_inc(&obj->obj_used);
  35         DEBUGMSG("Device %d opened %d times.\n", MINOR_NR, atomic_read(&obj->obj_used));
  36         can_msgobj_set_fl(obj,OPENED);
  37
  38         if (chip->flags & CHIP_CONFIGURED)
  39                 DEBUGMSG("Device is already configured.\n");
  40         else {
  41                 if (chip->chipspecops->chip_config(chip))
  42                         CANMSG("Error configuring chip.\n");
  43                 else
  44                         chip->flags |= CHIP_CONFIGURED;
  45
  46                 if (chip->chipspecops->pre_read_config(chip,obj)<0)
  47                         CANMSG("Error initializing chip for receiving\n");
  48
  49         } /* End of chip configuration */
  50
  51         canuser = (struct canuser_t *)kmalloc(sizeof(struct canuser_t), GFP_KERNEL);
  52         if(canuser == NULL) goto no_canuser;
  53         canuser->flags=0;
  54         canuser->userinfo.fileinfo.file = file;
  55         canuser->msgobj = obj;
  56         canuser->magic = CAN_USER_MAGIC;
  57         file->private_data = canuser;
  58
  59         qends = (struct canque_ends_t *)kmalloc(sizeof(struct canque_ends_t), GFP_KERNEL);
  60         if(qends == NULL) goto no_qends;
  61         canqueue_ends_init_kern(qends);
  62         canuser->qends = qends;
  63
  64         /*required to synchronize with RT-Linux context*/
  65         can_spin_lock_irqsave(&canuser_manipulation_lock, iflags);
  66         list_add(&canuser->peers, &obj->obj_users);
  67         can_spin_unlock_irqrestore(&canuser_manipulation_lock, iflags);
  68
  69         if(canqueue_connect_edge(edge=canque_new_edge_kern(MAX_BUF_LENGTH),
  70                 canuser->qends, obj->qends)<0) goto no_tx_qedge;
  71
  72         if(canqueue_connect_edge(canuser->rx_edge0=canque_new_edge_kern(MAX_BUF_LENGTH),
  73                 obj->qends, canuser->qends)<0) goto no_rx_qedge;
  74         /*FIXME: more generic model should be used there*/
  75         canque_edge_decref(canuser->rx_edge0);
  76         canque_edge_decref(edge);
  77
  78 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,50))
  79         MOD_INC_USE_COUNT;
  80 #endif
  81
  82         return 0;
  83
  84     no_rx_qedge:
  85         canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
  86         canque_edge_decref(edge);
  87     no_tx_qedge:
  88         list_del(&canuser->peers);
  89         canuser->qends = NULL;
  90         canqueue_ends_dispose_kern(qends, 1);
  91
  92     no_qends:
  93         kfree(canuser);
  94
  95     no_canuser:
  96         atomic_dec(&obj->obj_used);
  97         return -ENOMEM;
  98 }