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 */ 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); 105 106 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); 116 117 118 static int __init tape_init(void) 119 { 120 tape_class = class_create(THIS_MODULE, "tape390"); 121 122 return 0; 123 } 124 125 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