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