// SPDX-License-Identifier: GPL-2.0

#include <linux/device.h>
#include "my-ioctl.h"

MODULE_DESCRIPTION("Chardev Ioctl kernel module.");
MODULE_VERSION("0.0.1");
MODULE_AUTHOR("Imbus");
MODULE_LICENSE("GPL");

#define DEVICE_NAME "hello_ioctl"

static int major; /* Dynamically assigned */
static struct class *cls;

static long my_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);

/* See: https://elixir.bootlin.com/linux/v6.14.5/source/include/linux/fs.h#L2131 */
static const struct file_operations fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = my_ioctl,
};

static long my_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	pr_info("Ioctl called by %s...\n", current->comm);

	switch (cmd) {
	case MY_IOCTL_FILL:
		pr_info("Ioctl FILL by %s...\n", current->comm);
		break;
	case MY_IOCTL_WIPE:
		pr_info("Ioctl WIPE by %s...\n", current->comm);
		break;
	default:
		return -ENOTTY; // Invalid command
	}
	return 0;
}

static int __init demo_mod_init(void)
{
	major = register_chrdev(0, DEVICE_NAME, &fops);
	if (major < 0) {
		pr_info(DEVICE_NAME "  - Error registering chrdev\n");
		return major;
	}

	pr_info(DEVICE_NAME " was assigned major number %d.\n", major);

	cls = class_create(DEVICE_NAME);
	device_create(cls, NULL, MKDEV(major, 0), NULL, DEVICE_NAME);

	pr_info(DEVICE_NAME " created on /dev/%s\n", DEVICE_NAME);

	pr_info(DEVICE_NAME " major nbr %d loaded successfully...\n", major);
	return 0;
}

static void __exit demo_mod_exit(void)
{
	device_destroy(cls, MKDEV(major, 0));
	class_destroy(cls);
	unregister_chrdev(major, DEVICE_NAME);
	pr_info(DEVICE_NAME " unloaded successfully...\n");
}

module_init(demo_mod_init);
module_exit(demo_mod_exit);