drivers/s390/char/tape_class.c

   1 /*
   2  * (C) Copyright IBM Corp. 2004
   3  * tape_class.c
   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 #include "tape_class.h"
  11
  12 MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
  13 MODULE_DESCRIPTION(
  14         "(C) Copyright IBM Corp. 2004   All Rights Reserved.\n"
  15         "tape_class.c"
  16 );
  17 MODULE_LICENSE("GPL");
  18
  19 static struct class *tape_class;
  20
  21 /*
  22  * Register a tape device and return a pointer to the cdev structure.
  23  *
  24  * device
  25  *      The pointer to the struct device of the physical (base) device.
  26  * drivername
  27  *      The pointer to the drivers name for it's character devices.
  28  * dev
  29  *      The intended major/minor number. The major number may be 0 to
  30  *      get a dynamic major number.
  31  * fops
  32  *      The pointer to the drivers file operations for the tape device.
  33  * devname
  34  *      The pointer to the name of the character device.
  35  */
  36 struct tape_class_device *register_tape_dev(
  37         struct device *         device,
  38         dev_t                   dev,
  39         const struct file_operations *fops,
  40         char *                  device_name,
  41         char *                  mode_name)
  42 {
  43         struct tape_class_device *      tcd;
  44         int             rc;
  45         char *          s;
  46
  47         tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
  48         if (!tcd)
  49                 return ERR_PTR(-ENOMEM);
  50
  51         strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
  52         for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
  53                 *s = '!';
  54         strncpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
  55         for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
  56                 *s = '!';
  57
  58         tcd->char_device = cdev_alloc();
  59         if (!tcd->char_device) {
  60                 rc = -ENOMEM;
  61                 goto fail_with_tcd;
  62         }
  63
  64         tcd->char_device->owner = fops->owner;
  65         tcd->char_device->ops   = fops;
  66         tcd->char_device->dev   = dev;
  67
  68         rc = cdev_add(tcd->char_device, 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,
  74                                           "%s", tcd->device_name
  75                         );
  76         rc = IS_ERR(tcd->class_device) ? PTR_ERR(tcd->class_device) : 0;
  77         if (rc)
  78                 goto fail_with_cdev;
  79         rc = sysfs_create_link(
  80                 &device->kobj,
  81                 &tcd->class_device->kobj,
  82                 tcd->mode_name
  83         );
  84         if (rc)
  85                 goto fail_with_class_device;
  86
  87         return tcd;
  88
  89 fail_with_class_device:
  90         device_destroy(tape_class, tcd->char_device->dev);
  91
  92 fail_with_cdev:
  93         cdev_del(tcd->char_device);
  94
  95 fail_with_tcd:
  96         kfree(tcd);
  97
  98         return ERR_PTR(rc);
  99 }
 100 EXPORT_SYMBOL(register_tape_dev);
 101
 102 void unregister_tape_dev(struct tape_class_device *tcd)
 103 {
 104         if (tcd != NULL && !IS_ERR(tcd)) {
 105                 sysfs_remove_link(&tcd->class_device->kobj,
 106                                   tcd->mode_name);
 107                 device_destroy(tape_class, tcd->char_device->dev);
 108                 cdev_del(tcd->char_device);
 109                 kfree(tcd);
 110         }
 111 }
 112 EXPORT_SYMBOL(unregister_tape_dev);
 113
 114
 115 static int __init tape_init(void)
 116 {
 117         tape_class = class_create(THIS_MODULE, "tape390");
 118
 119         return 0;
 120 }
 121
 122 static void __exit tape_exit(void)
 123 {
 124         class_destroy(tape_class);
 125         tape_class = NULL;
 126 }
 127
 128 postcore_initcall(tape_init);
 129 module_exit(tape_exit);