1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2004
4 *
5 * Tape class device support
6 *
7 * Author: Stefan Bader <shbader@de.ibm.com>
8 * Based on simple class device code by Greg K-H
9 */
10
11 #define KMSG_COMPONENT "tape"
12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13
14 #include <linux/slab.h>
15
16 #include "tape_class.h"
17
18 MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
19 MODULE_DESCRIPTION(
20 "Copyright IBM Corp. 2004 All Rights Reserved.\n"
21 "tape_class.c"
22 );
23 MODULE_LICENSE("GPL");
24
25 static struct class *tape_class;
26
27 /*
28 * Register a tape device and return a pointer to the cdev structure.
29 *
30 * device
31 * The pointer to the struct device of the physical (base) device.
32 * drivername
33 * The pointer to the drivers name for it's character devices.
34 * dev
35 * The intended major/minor number. The major number may be 0 to
36 * get a dynamic major number.
37 * fops
38 * The pointer to the drivers file operations for the tape device.
39 * devname
40 * The pointer to the name of the character device.
41 */
register_tape_dev(struct device * device,dev_t dev,const struct file_operations * fops,char * device_name,char * mode_name)42 struct tape_class_device *register_tape_dev(
43 struct device * device,
44 dev_t dev,
45 const struct file_operations *fops,
46 char * device_name,
47 char * mode_name)
48 {
49 struct tape_class_device * tcd;
50 int rc;
51 char * s;
52
53 tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
54 if (!tcd)
55 return ERR_PTR(-ENOMEM);
56
57 strscpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
58 for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
59 *s = '!';
60 strscpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
61 for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
62 *s = '!';
63
64 tcd->char_device = cdev_alloc();
65 if (!tcd->char_device) {
66 rc = -ENOMEM;
67 goto fail_with_tcd;
68 }
69
70 tcd->char_device->owner = fops->owner;
71 tcd->char_device->ops = fops;
72
73 rc = cdev_add(tcd->char_device, dev, 1);
74 if (rc)
75 goto fail_with_cdev;
76
77 tcd->class_device = device_create(tape_class, device,
78 tcd->char_device->dev, NULL,
79 "%s", tcd->device_name);
80 rc = PTR_ERR_OR_ZERO(tcd->class_device);
81 if (rc)
82 goto fail_with_cdev;
83 rc = sysfs_create_link(
84 &device->kobj,
85 &tcd->class_device->kobj,
86 tcd->mode_name
87 );
88 if (rc)
89 goto fail_with_class_device;
90
91 return tcd;
92
93 fail_with_class_device:
94 device_destroy(tape_class, tcd->char_device->dev);
95
96 fail_with_cdev:
97 cdev_del(tcd->char_device);
98
99 fail_with_tcd:
100 kfree(tcd);
101
102 return ERR_PTR(rc);
103 }
104 EXPORT_SYMBOL(register_tape_dev);
105
unregister_tape_dev(struct device * device,struct tape_class_device * tcd)106 void unregister_tape_dev(struct device *device, struct tape_class_device *tcd)
107 {
108 if (tcd != NULL && !IS_ERR(tcd)) {
109 sysfs_remove_link(&device->kobj, tcd->mode_name);
110 device_destroy(tape_class, tcd->char_device->dev);
111 cdev_del(tcd->char_device);
112 kfree(tcd);
113 }
114 }
115 EXPORT_SYMBOL(unregister_tape_dev);
116
117
tape_init(void)118 static int __init tape_init(void)
119 {
120 tape_class = class_create(THIS_MODULE, "tape390");
121
122 return 0;
123 }
124
tape_exit(void)125 static void __exit tape_exit(void)
126 {
127 class_destroy(tape_class);
128 tape_class = NULL;
129 }
130
131 postcore_initcall(tape_init);
132 module_exit(tape_exit);
133