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 */ 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); 107 108 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); 118 119 120 static int __init tape_init(void) 121 { 122 return class_register(&tape_class); 123 } 124 125 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