/*
 *  User level driver support for input subsystem
 *
 * Heavily based on evdev.c by Vojtech Pavlik
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
 *
 * Changes/Revisions:
 *	0.1	20/06/2002
 *		- first public version
 */
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uinput.h>

static int uinput_dev_open(struct input_dev *dev)
{
	return 0;
}

static void uinput_dev_close(struct input_dev *dev)
{

}

static int uinput_dev_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
	struct uinput_device	*udev;

	udev = (struct uinput_device *)dev->private;

	udev->buff[udev->head].type = type;
	udev->buff[udev->head].code = code;
	udev->buff[udev->head].value = value;
	do_gettimeofday(&udev->buff[udev->head].time);
	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;

	wake_up_interruptible(&udev->waitq);

	return 0;
}

static int uinput_dev_upload_effect(struct input_dev *dev, struct ff_effect *effect)
{
	return 0;
}

static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
{
	return 0;
}

static int uinput_create_device(struct uinput_device *udev)
{
	if (!udev->dev->name) {
		printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
		return -EINVAL;
	}

	udev->dev->open = uinput_dev_open;
	udev->dev->close = uinput_dev_close;
	udev->dev->event = uinput_dev_event;
	udev->dev->upload_effect = uinput_dev_upload_effect;
	udev->dev->erase_effect = uinput_dev_erase_effect;
	udev->dev->private = udev;

	init_waitqueue_head(&(udev->waitq));

	input_register_device(udev->dev);

	set_bit(UIST_CREATED, &(udev->state));

	return 0;
}

static int uinput_destroy_device(struct uinput_device *udev)
{
	if (!test_bit(UIST_CREATED, &(udev->state))) {
		printk(KERN_WARNING "%s: create the device first\n", UINPUT_NAME);
		return -EINVAL;
	}

	input_unregister_device(udev->dev);

	clear_bit(UIST_CREATED, &(udev->state));

	return 0;
}

static int uinput_open(struct inode *inode, struct file *file)
{
	struct uinput_device	*newdev;
	struct input_dev	*newinput;

	newdev = kmalloc(sizeof(struct uinput_device), GFP_KERNEL);
	if (!newdev)
		goto error;
	memset(newdev, 0, sizeof(struct uinput_device));

	newinput = kmalloc(sizeof(struct input_dev), GFP_KERNEL);
	if (!newinput)
		goto cleanup;
	memset(newinput, 0, sizeof(struct input_dev));

	newdev->dev = newinput;

	file->private_data = newdev;

	return 0;
cleanup:
	kfree(newdev);
error:
	return -ENOMEM;
}

static int uinput_validate_absbits(struct input_dev *dev)
{
	unsigned int cnt;
	int retval = 0;

	for (cnt = 0; cnt < ABS_MAX; cnt++) {
		if (!test_bit(cnt, dev->absbit))
			continue;

		if (/*!dev->absmin[cnt] || !dev->absmax[cnt] || */
		    (dev->absmax[cnt] <= dev->absmin[cnt])) {
			printk(KERN_DEBUG
				"%s: invalid abs[%02x] min:%d max:%d\n",
				UINPUT_NAME, cnt,
				dev->absmin[cnt], dev->absmax[cnt]);
			retval = -EINVAL;
			break;
		}

		if ((dev->absflat[cnt] < dev->absmin[cnt]) ||
		    (dev->absflat[cnt] > dev->absmax[cnt])) {
			printk(KERN_DEBUG
				"%s: absflat[%02x] out of range: %d "
				"(min:%d/max:%d)\n",
				UINPUT_NAME, cnt, dev->absflat[cnt],
				dev->absmin[cnt], dev->absmax[cnt]);
			retval = -EINVAL;
			break;
		}
	}
	return retval;
}

static int uinput_alloc_device(struct file *file, const char __user *buffer, size_t count)
{
	struct uinput_user_dev	*user_dev;
	struct input_dev	*dev;
	struct uinput_device	*udev;
	int			size,
				retval;

	retval = count;

	udev = (struct uinput_device *)file->private_data;
	dev = udev->dev;

	user_dev = kmalloc(sizeof(*user_dev), GFP_KERNEL);
	if (!user_dev) {
		retval = -ENOMEM;
		goto exit;
	}

	if (copy_from_user(user_dev, buffer, sizeof(struct uinput_user_dev))) {
		retval = -EFAULT;
		goto exit;
	}

	if (NULL != dev->name)
		kfree(dev->name);

	size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE) + 1;
	dev->name = kmalloc(size, GFP_KERNEL);
	if (!dev->name) {
		retval = -ENOMEM;
		goto exit;
	}

	strlcpy(dev->name, user_dev->name, size);
	dev->id.bustype	= user_dev->id.bustype;
	dev->id.vendor	= user_dev->id.vendor;
	dev->id.product	= user_dev->id.product;
	dev->id.version	= user_dev->id.version;
	dev->ff_effects_max = user_dev->ff_effects_max;

	size = sizeof(int) * (ABS_MAX + 1);
	memcpy(dev->absmax, user_dev->absmax, size);
	memcpy(dev->absmin, user_dev->absmin, size);
	memcpy(dev->absfuzz, user_dev->absfuzz, size);
	memcpy(dev->absflat, user_dev->absflat, size);

	/* check if absmin/absmax/absfuzz/absflat are filled as
	 * told in Documentation/input/input-programming.txt */
	if (test_bit(EV_ABS, dev->evbit)) {
		retval = uinput_validate_absbits(dev);
		if (retval < 0)
			kfree(dev->name);
	}

exit:
	kfree(user_dev);
	return retval;
}

static ssize_t uinput_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	struct uinput_device	*udev = file->private_data;

	if (test_bit(UIST_CREATED, &(udev->state))) {
		struct input_event	ev;

		if (copy_from_user(&ev, buffer, sizeof(struct input_event)))
			return -EFAULT;
		input_event(udev->dev, ev.type, ev.code, ev.value);
	}
	else
		count = uinput_alloc_device(file, buffer, count);

	return count;
}

static ssize_t uinput_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
	struct uinput_device *udev = file->private_data;
	int retval = 0;

	if (!test_bit(UIST_CREATED, &(udev->state)))
		return -ENODEV;

	if ((udev->head == udev->tail) && (file->f_flags & O_NONBLOCK))
		return -EAGAIN;

	retval = wait_event_interruptible(udev->waitq,
			(udev->head != udev->tail) ||
			!test_bit(UIST_CREATED, &(udev->state)));

	if (retval)
		return retval;

	if (!test_bit(UIST_CREATED, &(udev->state)))
		return -ENODEV;

	while ((udev->head != udev->tail) &&
	    (retval + sizeof(struct input_event) <= count)) {
		if (copy_to_user(buffer + retval, &(udev->buff[udev->tail]),
		    sizeof(struct input_event))) return -EFAULT;
		udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
		retval += sizeof(struct input_event);
	}

	return retval;
}

static unsigned int uinput_poll(struct file *file, poll_table *wait)
{
	struct uinput_device *udev = file->private_data;

	if (!test_bit(UIST_CREATED, &(udev->state)))
		return 0;

	poll_wait(file, &udev->waitq, wait);

	if (udev->head != udev->tail)
		return POLLIN | POLLRDNORM;

	return 0;
}

static int uinput_burn_device(struct uinput_device *udev)
{
	if (test_bit(UIST_CREATED, &(udev->state)))
		uinput_destroy_device(udev);

	kfree(udev->dev);
	kfree(udev);

	return 0;
}

static int uinput_close(struct inode *inode, struct file *file)
{
	return uinput_burn_device((struct uinput_device *)file->private_data);
}

static int uinput_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	int			retval = 0;
	struct uinput_device	*udev;

	udev = (struct uinput_device *)file->private_data;

	/* device attributes can not be changed after the device is created */
	if (cmd >= UI_SET_EVBIT && test_bit(UIST_CREATED, &(udev->state)))
		return -EINVAL;

	switch (cmd) {
		case UI_DEV_CREATE:
			retval = uinput_create_device(udev);
			break;

		case UI_DEV_DESTROY:
			retval = uinput_destroy_device(udev);
			break;

		case UI_SET_EVBIT:
			if (arg > EV_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->evbit);
			break;

		case UI_SET_KEYBIT:
			if (arg > KEY_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->keybit);
			break;

		case UI_SET_RELBIT:
			if (arg > REL_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->relbit);
			break;

		case UI_SET_ABSBIT:
			if (arg > ABS_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->absbit);
			break;

		case UI_SET_MSCBIT:
			if (arg > MSC_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->mscbit);
			break;

		case UI_SET_LEDBIT:
			if (arg > LED_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->ledbit);
			break;

		case UI_SET_SNDBIT:
			if (arg > SND_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->sndbit);
			break;

		case UI_SET_FFBIT:
			if (arg > FF_MAX) {
				retval = -EINVAL;
				break;
			}
			set_bit(arg, udev->dev->ffbit);
			break;

		default:
			retval = -EFAULT;
	}
	return retval;
}

struct file_operations uinput_fops = {
	.owner =	THIS_MODULE,
	.open =		uinput_open,
	.release =	uinput_close,
	.read =		uinput_read,
	.write =	uinput_write,
	.poll =		uinput_poll,
	.ioctl =	uinput_ioctl,
};

static struct miscdevice uinput_misc = {
	.fops =		&uinput_fops,
	.minor =	UINPUT_MINOR,
	.name =		UINPUT_NAME,
};

static int __init uinput_init(void)
{
	return misc_register(&uinput_misc);
}

static void __exit uinput_exit(void)
{
	misc_deregister(&uinput_misc);
}

MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
MODULE_DESCRIPTION("User level driver support for input subsystem");
MODULE_LICENSE("GPL");

module_init(uinput_init);
module_exit(uinput_exit);