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
18MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
19MODULE_DESCRIPTION(
20	"Copyright IBM Corp. 2004   All Rights Reserved.\n"
21	"tape_class.c"
22);
23MODULE_LICENSE("GPL");
24
25static 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 */
42struct 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	strlcpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
58	for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
59		*s = '!';
60	strlcpy(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
93fail_with_class_device:
94	device_destroy(tape_class, tcd->char_device->dev);
95
96fail_with_cdev:
97	cdev_del(tcd->char_device);
98
99fail_with_tcd:
100	kfree(tcd);
101
102	return ERR_PTR(rc);
103}
104EXPORT_SYMBOL(register_tape_dev);
105
106void 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}
115EXPORT_SYMBOL(unregister_tape_dev);
116
117
118static int __init tape_init(void)
119{
120	tape_class = class_create(THIS_MODULE, "tape390");
121
122	return 0;
123}
124
125static void __exit tape_exit(void)
126{
127	class_destroy(tape_class);
128	tape_class = NULL;
129}
130
131postcore_initcall(tape_init);
132module_exit(tape_exit);
133