s390/char/tape_class.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright IBM Corp. 2004
0004  *
0005  * Tape class device support
0006  *
0007  * Author: Stefan Bader <shbader@de.ibm.com>
0008  * Based on simple class device code by Greg K-H
0009  */
0010
0011 #define KMSG_COMPONENT "tape"
0012 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
0013
0014 #include <linux/slab.h>
0015
0016 #include "tape_class.h"
0017
0018 MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
0019 MODULE_DESCRIPTION(
0020     "Copyright IBM Corp. 2004   All Rights Reserved.\n"
0021     "tape_class.c"
0022 );
0023 MODULE_LICENSE("GPL");
0024
0025 static struct class *tape_class;
0026
0027 /*
0028  * Register a tape device and return a pointer to the cdev structure.
0029  *
0030  * device
0031  *  The pointer to the struct device of the physical (base) device.
0032  * drivername
0033  *  The pointer to the drivers name for it's character devices.
0034  * dev
0035  *  The intended major/minor number. The major number may be 0 to
0036  *  get a dynamic major number.
0037  * fops
0038  *  The pointer to the drivers file operations for the tape device.
0039  * devname
0040  *  The pointer to the name of the character device.
0041  */
0042 struct tape_class_device *register_tape_dev(
0043     struct device *     device,
0044     dev_t           dev,
0045     const struct file_operations *fops,
0046     char *          device_name,
0047     char *          mode_name)
0048 {
0049     struct tape_class_device *  tcd;
0050     int     rc;
0051     char *      s;
0052
0053     tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
0054     if (!tcd)
0055         return ERR_PTR(-ENOMEM);
0056
0057     strlcpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
0058     for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
0059         *s = '!';
0060     strlcpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
0061     for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
0062         *s = '!';
0063
0064     tcd->char_device = cdev_alloc();
0065     if (!tcd->char_device) {
0066         rc = -ENOMEM;
0067         goto fail_with_tcd;
0068     }
0069
0070     tcd->char_device->owner = fops->owner;
0071     tcd->char_device->ops   = fops;
0072
0073     rc = cdev_add(tcd->char_device, dev, 1);
0074     if (rc)
0075         goto fail_with_cdev;
0076
0077     tcd->class_device = device_create(tape_class, device,
0078                       tcd->char_device->dev, NULL,
0079                       "%s", tcd->device_name);
0080     rc = PTR_ERR_OR_ZERO(tcd->class_device);
0081     if (rc)
0082         goto fail_with_cdev;
0083     rc = sysfs_create_link(
0084         &device->kobj,
0085         &tcd->class_device->kobj,
0086         tcd->mode_name
0087     );
0088     if (rc)
0089         goto fail_with_class_device;
0090
0091     return tcd;
0092
0093 fail_with_class_device:
0094     device_destroy(tape_class, tcd->char_device->dev);
0095
0096 fail_with_cdev:
0097     cdev_del(tcd->char_device);
0098
0099 fail_with_tcd:
0100     kfree(tcd);
0101
0102     return ERR_PTR(rc);
0103 }
0104 EXPORT_SYMBOL(register_tape_dev);
0105
0106 void unregister_tape_dev(struct device *device, struct tape_class_device *tcd)
0107 {
0108     if (tcd != NULL && !IS_ERR(tcd)) {
0109         sysfs_remove_link(&device->kobj, tcd->mode_name);
0110         device_destroy(tape_class, tcd->char_device->dev);
0111         cdev_del(tcd->char_device);
0112         kfree(tcd);
0113     }
0114 }
0115 EXPORT_SYMBOL(unregister_tape_dev);
0116
0117
0118 static int __init tape_init(void)
0119 {
0120     tape_class = class_create(THIS_MODULE, "tape390");
0121
0122     return 0;
0123 }
0124
0125 static void __exit tape_exit(void)
0126 {
0127     class_destroy(tape_class);
0128     tape_class = NULL;
0129 }
0130
0131 postcore_initcall(tape_init);
0132 module_exit(tape_exit);