tape_class.c
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/*
* Copyright IBM Corp. 2004
*
* Tape class device support
*
* Author: Stefan Bader <shbader@de.ibm.com>
* Based on simple class device code by Greg K-H
*/
#define KMSG_COMPONENT "tape"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/slab.h>
#include "tape_class.h"
MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
MODULE_DESCRIPTION(
"Copyright IBM Corp. 2004 All Rights Reserved.\n"
"tape_class.c"
);
MODULE_LICENSE("GPL");
static struct class *tape_class;
/*
* Register a tape device and return a pointer to the cdev structure.
*
* device
* The pointer to the struct device of the physical (base) device.
* drivername
* The pointer to the drivers name for it's character devices.
* dev
* The intended major/minor number. The major number may be 0 to
* get a dynamic major number.
* fops
* The pointer to the drivers file operations for the tape device.
* devname
* The pointer to the name of the character device.
*/
struct tape_class_device *register_tape_dev(
struct device * device,
dev_t dev,
const struct file_operations *fops,
char * device_name,
char * mode_name)
{
struct tape_class_device * tcd;
int rc;
char * s;
tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
if (!tcd)
return ERR_PTR(-ENOMEM);
strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
*s = '!';
strncpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
*s = '!';
tcd->char_device = cdev_alloc();
if (!tcd->char_device) {
rc = -ENOMEM;
goto fail_with_tcd;
}
tcd->char_device->owner = fops->owner;
tcd->char_device->ops = fops;
tcd->char_device->dev = dev;
rc = cdev_add(tcd->char_device, tcd->char_device->dev, 1);
if (rc)
goto fail_with_cdev;
tcd->class_device = device_create(tape_class, device,
tcd->char_device->dev, NULL,
"%s", tcd->device_name);
rc = PTR_RET(tcd->class_device);
if (rc)
goto fail_with_cdev;
rc = sysfs_create_link(
&device->kobj,
&tcd->class_device->kobj,
tcd->mode_name
);
if (rc)
goto fail_with_class_device;
return tcd;
fail_with_class_device:
device_destroy(tape_class, tcd->char_device->dev);
fail_with_cdev:
cdev_del(tcd->char_device);
fail_with_tcd:
kfree(tcd);
return ERR_PTR(rc);
}
EXPORT_SYMBOL(register_tape_dev);
void unregister_tape_dev(struct device *device, struct tape_class_device *tcd)
{
if (tcd != NULL && !IS_ERR(tcd)) {
sysfs_remove_link(&device->kobj, tcd->mode_name);
device_destroy(tape_class, tcd->char_device->dev);
cdev_del(tcd->char_device);
kfree(tcd);
}
}
EXPORT_SYMBOL(unregister_tape_dev);
static int __init tape_init(void)
{
tape_class = class_create(THIS_MODULE, "tape390");
return 0;
}
static void __exit tape_exit(void)
{
class_destroy(tape_class);
tape_class = NULL;
}
postcore_initcall(tape_init);
module_exit(tape_exit);