drivers/s390/char/tape_class.c

   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);