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   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
  11 #define KMSG_COMPONENT "tape"
  12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14 #include "tape_class.h"
  15
  16 MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
  17 MODULE_DESCRIPTION(
  18         "(C) Copyright IBM Corp. 2004   All Rights Reserved.\n"
  19         "tape_class.c"
  20 );
  21 MODULE_LICENSE("GPL");
  22
  23 static struct class *tape_class;
  24
  25 /*
  26  * Register a tape device and return a pointer to the cdev structure.
  27  *
  28  * device
  29  *      The pointer to the struct device of the physical (base) device.
  30  * drivername
  31  *      The pointer to the drivers name for it's character devices.
  32  * dev
  33  *      The intended major/minor number. The major number may be 0 to
  34  *      get a dynamic major number.
  35  * fops
  36  *      The pointer to the drivers file operations for the tape device.
  37  * devname
  38  *      The pointer to the name of the character device.
  39  */
  40 struct tape_class_device *register_tape_dev(
  41         struct device *         device,
  42         dev_t                   dev,
  43         const struct file_operations *fops,
  44         char *                  device_name,
  45         char *                  mode_name)
  46 {
  47         struct tape_class_device *      tcd;
  48         int             rc;
  49         char *          s;
  50
  51         tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
  52         if (!tcd)
  53                 return ERR_PTR(-ENOMEM);
  54
  55         strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
  56         for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
  57                 *s = '!';
  58         strncpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
  59         for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
  60                 *s = '!';
  61
  62         tcd->char_device = cdev_alloc();
  63         if (!tcd->char_device) {
  64                 rc = -ENOMEM;
  65                 goto fail_with_tcd;
  66         }
  67
  68         tcd->char_device->owner = fops->owner;
  69         tcd->char_device->ops   = fops;
  70         tcd->char_device->dev   = dev;
  71
  72         rc = cdev_add(tcd->char_device, tcd->char_device->dev, 1);
  73         if (rc)
  74                 goto fail_with_cdev;
  75
  76         tcd->class_device = device_create(tape_class, device,
  77                                           tcd->char_device->dev, NULL,
  78                                           "%s", tcd->device_name);
  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         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 device *device, struct tape_class_device *tcd)
 106 {
 107         if (tcd != NULL && !IS_ERR(tcd)) {
 108                 sysfs_remove_link(&device->kobj, tcd->mode_name);
 109                 device_destroy(tape_class, tcd->char_device->dev);
 110                 cdev_del(tcd->char_device);
 111                 kfree(tcd);
 112         }
 113 }
 114 EXPORT_SYMBOL(unregister_tape_dev);
 115
 116
 117 static int __init tape_init(void)
 118 {
 119         tape_class = class_create(THIS_MODULE, "tape390");
 120
 121         return 0;
 122 }
 123
 124 static void __exit tape_exit(void)
 125 {
 126         class_destroy(tape_class);
 127         tape_class = NULL;
 128 }
 129
 130 postcore_initcall(tape_init);
 131 module_exit(tape_exit);