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 pr_fmt(fmt) "tape: " fmt 12 13 #include <linux/export.h> 14 #include <linux/slab.h> 15 16 #include "tape_class.h" 17 18 static const struct class tape_class = { 19 .name = "tape390", 20 }; 21 22 /* 23 * Register a tape device and return a pointer to the cdev structure. 24 * 25 * device 26 * The pointer to the struct device of the physical (base) device. 27 * drivername 28 * The pointer to the drivers name for it's character devices. 29 * dev 30 * The intended major/minor number. The major number may be 0 to 31 * get a dynamic major number. 32 * fops 33 * The pointer to the drivers file operations for the tape device. 34 * devname 35 * The pointer to the name of the character device. 36 */ 37 struct tape_class_device *register_tape_dev( 38 struct device * device, 39 dev_t dev, 40 const struct file_operations *fops, 41 char * device_name, 42 char * mode_name) 43 { 44 struct tape_class_device * tcd; 45 int rc; 46 char * s; 47 48 tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL); 49 if (!tcd) 50 return ERR_PTR(-ENOMEM); 51 52 strscpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN); 53 for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/')) 54 *s = '!'; 55 strscpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN); 56 for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/')) 57 *s = '!'; 58 59 tcd->char_device = cdev_alloc(); 60 if (!tcd->char_device) { 61 rc = -ENOMEM; 62 goto fail_with_tcd; 63 } 64 65 tcd->char_device->owner = fops->owner; 66 tcd->char_device->ops = fops; 67 68 rc = cdev_add(tcd->char_device, dev, 1); 69 if (rc) 70 goto fail_with_cdev; 71 72 tcd->class_device = device_create(&tape_class, device, 73 tcd->char_device->dev, NULL, 74 "%s", tcd->device_name); 75 rc = PTR_ERR_OR_ZERO(tcd->class_device); 76 if (rc) 77 goto fail_with_cdev; 78 rc = sysfs_create_link( 79 &device->kobj, 80 &tcd->class_device->kobj, 81 tcd->mode_name 82 ); 83 if (rc) 84 goto fail_with_class_device; 85 86 return tcd; 87 88 fail_with_class_device: 89 device_destroy(&tape_class, tcd->char_device->dev); 90 91 fail_with_cdev: 92 cdev_del(tcd->char_device); 93 94 fail_with_tcd: 95 kfree(tcd); 96 97 return ERR_PTR(rc); 98 } 99 EXPORT_SYMBOL(register_tape_dev); 100 101 void unregister_tape_dev(struct device *device, struct tape_class_device *tcd) 102 { 103 if (tcd != NULL && !IS_ERR(tcd)) { 104 sysfs_remove_link(&device->kobj, tcd->mode_name); 105 device_destroy(&tape_class, tcd->char_device->dev); 106 cdev_del(tcd->char_device); 107 kfree(tcd); 108 } 109 } 110 EXPORT_SYMBOL(unregister_tape_dev); 111 112 int tape_class_init(void) 113 { 114 return class_register(&tape_class); 115 } 116 117 void tape_class_exit(void) 118 { 119 class_unregister(&tape_class); 120 } 121