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