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 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         strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
  58         for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
  59                 *s = '!';
  60         strncpy(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_RET(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);