#include "char.h"

#include "linux/cdev.h"
#include "linux/device.h"
#include "linux/fs.h"

#include "util.h"

#define DOOMDEV_COUNT 256
#define DOOMDEV_NAME "doom"

dev_t first;
int major;
int next_minor = 0;

long doom_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	return -1;
}

int doom_open(struct inode *inode, struct file *filp)
{
	return -1;
}

struct file_operations doomdev_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = doom_ioctl,
	.compat_ioctl = doom_ioctl,
	.open = doom_open
};
	
struct class *doom_class;

int new_doomdev(void)
{
	int err = 0;
	int minor;
	dev_t devt;
	struct cdev *doom_cdev;
	struct device *doomdev;
	if (next_minor >= DOOMDEV_COUNT) {
		return -ENOMEM;
	}

	doom_cdev = cdev_alloc();
	if (doom_cdev == NULL) {
		return -ENOMEM;
	}

	doom_cdev->ops = &doomdev_fops;
	ORFAIL(cdev_add(doom_cdev, first, 1), error_add);
	minor = next_minor++;
	devt = MKDEV(major, minor);
	ORFAIL_PTR(device_create(doom_class, NULL, devt, NULL,
				"doom%d", minor),
			doomdev, error_create);

error_create:
	cdev_del(doom_cdev);
error_add:
	return err;
}

void destroy_doomdev(void)
{
	device_destroy(doom_class, first);
}

int char_init(void)
{
	int err = 0;
	ORFAIL(alloc_chrdev_region(&first, 0, DOOMDEV_COUNT, DOOMDEV_NAME),
			error_region);
	major = MAJOR(first);
	doom_class = class_create(THIS_MODULE, "doom");
	if (IS_ERR(doom_class)) {
		err = PTR_ERR(doom_class);
		goto error_create;
	}

error_create:
	unregister_chrdev_region(first, DOOMDEV_COUNT);
error_region:
	return err;
}

void char_cleanup(void)
{
	unregister_chrdev_region(first, DOOMDEV_COUNT);
	class_unregister(doom_class);
}