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/i82527.h"
  15 #include "../include/setup.h"
  16
  17 #define __NO_VERSION__
  18 #include <linux/module.h>
  19
  20 int can_open(struct inode *inode, struct file *file)
  21 {
  22         struct msgobj_t *obj;
  23         struct canchip_t *chip;
  24         struct canuser_t *canuser;
  25         struct canque_ends_t *qends;
  26         struct canque_edge_t *edge;
  27         can_spin_irqflags_t iflags;
  28
  29         if ( ((obj=objects_p[MINOR_NR]) == NULL) ||
  30                         ((chip=objects_p[MINOR_NR]->hostchip) == NULL) ) {
  31                 CANMSG("There is no hardware support for the device file with minor nr.: %d\n",MINOR_NR);
  32                 return -ENODEV;
  33         }
  34
  35         atomic_inc(&obj->obj_used);
  36         DEBUGMSG("Device %d opened %d times.\n", MINOR_NR, atomic_read(&obj->obj_used));
  37         can_msgobj_set_fl(obj,OPENED);
  38
  39         if (chip->flags & CHIP_CONFIGURED)
  40                 DEBUGMSG("Device is already configured.\n");
  41         else {
  42                 if (chip->chipspecops->chip_config(chip))
  43                         CANMSG("Error configuring chip.\n");
  44                 else
  45                         chip->flags |= CHIP_CONFIGURED;
  46
  47                 if (chip->chipspecops->pre_read_config(chip,obj)<0)
  48                         CANMSG("Error initializing chip for receiving\n");
  49
  50         } /* End of chip configuration */
  51
  52         canuser = (struct canuser_t *)kmalloc(sizeof(struct canuser_t), GFP_KERNEL);
  53         if(canuser == NULL) goto no_canuser;
  54         canuser->flags=0;
  55         canuser->userinfo.fileinfo.file = file;
  56         canuser->msgobj = obj;
  57         canuser->magic = CAN_USER_MAGIC;
  58         file->private_data = canuser;
  59
  60         qends = (struct canque_ends_t *)kmalloc(sizeof(struct canque_ends_t), GFP_KERNEL);
  61         if(qends == NULL) goto no_qends;
  62         canqueue_ends_init_kern(qends);
  63         canuser->qends = qends;
  64
  65         /*required to synchronize with RT-Linux context*/
  66         can_spin_lock_irqsave(&canuser_manipulation_lock, iflags);
  67         list_add(&canuser->peers, &obj->obj_users);
  68         can_spin_unlock_irqrestore(&canuser_manipulation_lock, iflags);
  69
  70         if(canqueue_connect_edge(edge=canque_new_edge_kern(MAX_BUF_LENGTH),
  71                 canuser->qends, obj->qends)<0) goto no_tx_qedge;
  72
  73         if(canqueue_connect_edge(canuser->rx_edge0=canque_new_edge_kern(MAX_BUF_LENGTH),
  74                 obj->qends, canuser->qends)<0) goto no_rx_qedge;
  75         /*FIXME: more generic model should be used there*/
  76         canque_edge_decref(canuser->rx_edge0);
  77         canque_edge_decref(edge);
  78
  79 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,50))
  80         MOD_INC_USE_COUNT;
  81 #endif
  82
  83         return 0;
  84
  85     no_rx_qedge:
  86         canque_notify_bothends(edge, CANQUEUE_NOTIFY_DEAD_WANTED);
  87         canque_edge_decref(edge);
  88     no_tx_qedge:
  89         list_del(&canuser->peers);
  90         canuser->qends = NULL;
  91         canqueue_ends_dispose_kern(qends, 1);
  92
  93     no_qends:
  94         kfree(canuser);
  95
  96     no_canuser:
  97         atomic_dec(&obj->obj_used);
  98         return -ENOMEM;
  99 }