LXR linux/drivers/s390/char/tape

   1/*
   2 * Copyright IBM Corp. 2004
   3 *
   4 * Tape class device support
   5 *
   6 * Author: Stefan Bader <shbader@de.ibm.com>
   7 * Based on simple class device code by Greg K-H
   8 */
   9
  10#define KMSG_COMPONENT "tape"
  11#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  12
  13#include <linux/slab.h>
  14
  15#include "tape_class.h"
  16
  17MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
  18MODULE_DESCRIPTION(
  19        "Copyright IBM Corp. 2004   All Rights Reserved.\n"
  20        "tape_class.c"
  21);
  22MODULE_LICENSE("GPL");
  23
  24static struct class *tape_class;
  25
  26/*
  27 * Register a tape device and return a pointer to the cdev structure.
  28 *
  29 * device
  30 *      The pointer to the struct device of the physical (base) device.
  31 * drivername
  32 *      The pointer to the drivers name for it's character devices.
  33 * dev
  34 *      The intended major/minor number. The major number may be 0 to
  35 *      get a dynamic major number.
  36 * fops
  37 *      The pointer to the drivers file operations for the tape device.
  38 * devname
  39 *      The pointer to the name of the character device.
  40 */
  41struct tape_class_device *register_tape_dev(
  42        struct device *         device,
  43        dev_t                   dev,
  44        const struct file_operations *fops,
  45        char *                  device_name,
  46        char *                  mode_name)
  47{
  48        struct tape_class_device *      tcd;
  49        int             rc;
  50        char *          s;
  51
  52        tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
  53        if (!tcd)
  54                return ERR_PTR(-ENOMEM);
  55
  56        strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
  57        for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
  58                *s = '!';
  59        strncpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
  60        for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
  61                *s = '!';
  62
  63        tcd->char_device = cdev_alloc();
  64        if (!tcd->char_device) {
  65                rc = -ENOMEM;
  66                goto fail_with_tcd;
  67        }
  68
  69        tcd->char_device->owner = fops->owner;
  70        tcd->char_device->ops   = fops;
  71        tcd->char_device->dev   = dev;
  72
  73        rc = cdev_add(tcd->char_device, 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
  93fail_with_class_device:
  94        device_destroy(tape_class, tcd->char_device->dev);
  95
  96fail_with_cdev:
  97        cdev_del(tcd->char_device);
  98
  99fail_with_tcd:
 100        kfree(tcd);
 101
 102        return ERR_PTR(rc);
 103}
 104EXPORT_SYMBOL(register_tape_dev);
 105
 106void 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}
 115EXPORT_SYMBOL(unregister_tape_dev);
 116
 117
 118static int __init tape_init(void)
 119{
 120        tape_class = class_create(THIS_MODULE, "tape390");
 121
 122        return 0;
 123}
 124
 125static void __exit tape_exit(void)
 126{
 127        class_destroy(tape_class);
 128        tape_class = NULL;
 129}
 130
 131postcore_initcall(tape_init);
 132module_exit(tape_exit);
 133