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 = class_device_create(
  73                                 tape_class,
  74                                 NULL,
  75                                 tcd->char_device->dev,
  76                                 device,
  77                                 "%s", tcd->device_name
  78                         );
  79         rc = IS_ERR(tcd->class_device) ? PTR_ERR(tcd->class_device) : 0;
  80         if (rc)
  81                 goto fail_with_cdev;
  82         rc = sysfs_create_link(
  83                 &device->kobj,
  84                 &tcd->class_device->kobj,
  85                 tcd->mode_name
  86         );
  87         if (rc)
  88                 goto fail_with_class_device;
  89
  90         return tcd;
  91
  92 fail_with_class_device:
  93         class_device_destroy(tape_class, tcd->char_device->dev);
  94
  95 fail_with_cdev:
  96         cdev_del(tcd->char_device);
  97
  98 fail_with_tcd:
  99         kfree(tcd);
 100
 101         return ERR_PTR(rc);
 102 }
 103 EXPORT_SYMBOL(register_tape_dev);
 104
 105 void unregister_tape_dev(struct tape_class_device *tcd)
 106 {
 107         if (tcd != NULL && !IS_ERR(tcd)) {
 108                 sysfs_remove_link(
 109                         &tcd->class_device->dev->kobj,
 110                         tcd->mode_name
 111                 );
 112                 class_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         tape_class = class_create(THIS_MODULE, "tape390");
 123
 124         return 0;
 125 }
 126
 127 static void __exit tape_exit(void)
 128 {
 129         class_destroy(tape_class);
 130         tape_class = NULL;
 131 }
 132
 133 postcore_initcall(tape_init);
 134 module_exit(tape_exit);