#include "char.h"

#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/fs.h>

#include "util.h"
#include "pci.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(struct pci_dev *dev)
{
	int err = 0;
	int minor;
	struct doom_data *doom_data;
	dev_t devt;

	if (next_minor >= DOOMDEV_COUNT) {
		return -ENOMEM;
	}

	doom_data = kmalloc(sizeof(*doom_data), GFP_KERNEL);
	if (doom_data == NULL) {
		err = -ENOMEM;
		goto error_kmalloc;
	}

	doom_data->cdev = cdev_alloc();
	if (doom_data->cdev == NULL) {
		err = -ENOMEM;
		goto error_cdev;
	}
	cdev_init(doom_data->cdev, &doomdev_fops);
	ORFAIL(cdev_add(doom_data->cdev, first, 1), error_add);

	minor = next_minor++;
	devt = MKDEV(major, minor);
	doom_data->device = device_create(doom_class, &dev->dev, devt, NULL,
				"doom%d", minor),
	ORFAIL_PTR(doom_data->device, error_create);
	
	pci_set_drvdata(dev, doom_data);

	return 0;

error_create:
	cdev_del(doom_data->cdev);
error_add:
error_cdev:
	kfree(doom_data);
error_kmalloc:
	return err;
}

void destroy_doomdev(struct pci_dev *dev)
{
	struct doom_data *data;

	data = pci_get_drvdata(dev);
	device_destroy(doom_class, data->device->devt);
	cdev_del(data->cdev);
	kfree(data);
}

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");
	ORFAIL_PTR(doom_class, error_create);

	return 0;

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);
	class_destroy(doom_class);
}