Structured comments updated.
[lincan.git] / 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-0.2  9 Jul 2003
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 chip_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 }