/*
   *  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:
   *	0.3	09/04/2006 (Anssi Hannula <anssi.hannula@gmail.com>)
   *		- updated ff support for the changes in kernel interface
   *		- added MODULE_VERSION
   *	0.2	16/10/2004 (Micah Dowty <micah@navi.cx>)
   *		- added force feedback support
   *              - added UI_SET_PHYS
   *	0.1	20/06/2002
   *		- first public version
   */
  #include <linux/poll.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/fs.h>
  #include <linux/miscdevice.h>
  #include <linux/uinput.h>
  #include <linux/input/mt.h>
  #include "../input-compat.h"
  
  static int uinput_dev_event(struct input_dev *dev,
  			    unsigned int type, unsigned int code, int value)
  {
  	struct uinput_device	*udev = input_get_drvdata(dev);
  
  	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;
  }
  
  /* Atomically allocate an ID for the given request. Returns 0 on success. */
  static bool uinput_request_alloc_id(struct uinput_device *udev,
  				    struct uinput_request *request)
  {
  	unsigned int id;
  	bool reserved = false;
  
  	spin_lock(&udev->requests_lock);
  
  	for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
  		if (!udev->requests[id]) {
  			request->id = id;
  			udev->requests[id] = request;
  			reserved = true;
  			break;
  		}
  	}
  
  	spin_unlock(&udev->requests_lock);
  	return reserved;
  }
  
  static struct uinput_request *uinput_request_find(struct uinput_device *udev,
  						  unsigned int id)
  {
  	/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
  	if (id >= UINPUT_NUM_REQUESTS)
  		return NULL;
  
  	return udev->requests[id];
  }
  
  static int uinput_request_reserve_slot(struct uinput_device *udev,
  				       struct uinput_request *request)
  {
  	/* Allocate slot. If none are available right away, wait. */
  	return wait_event_interruptible(udev->requests_waitq,
  					uinput_request_alloc_id(udev, request));
  }
  
  static void uinput_request_done(struct uinput_device *udev,
  				struct uinput_request *request)
  {
  	/* Mark slot as available */
  	udev->requests[request->id] = NULL;
  	wake_up(&udev->requests_waitq);
  
  	complete(&request->done);
  }
  
  static int uinput_request_send(struct uinput_device *udev,
  			       struct uinput_request *request)
  {
  	int retval;
  
  	retval = mutex_lock_interruptible(&udev->mutex);
  	if (retval)
  		return retval;
  
  	if (udev->state != UIST_CREATED) {
  		retval = -ENODEV;
  		goto out;
  	}
  
  	init_completion(&request->done);
  
  	/*
  	 * Tell our userspace application about this new request
  	 * by queueing an input event.
  	 */
  	uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
  
   out:
  	mutex_unlock(&udev->mutex);
  	return retval;
  }
  
  static int uinput_request_submit(struct uinput_device *udev,
  				 struct uinput_request *request)
  {
  	int error;
  
  	error = uinput_request_reserve_slot(udev, request);
  	if (error)
  		return error;
  
  	error = uinput_request_send(udev, request);
  	if (error) {
  		uinput_request_done(udev, request);
  		return error;
  	}
  
  	wait_for_completion(&request->done);
  	return request->retval;
  }
  
  /*
   * Fail all outstanding requests so handlers don't wait for the userspace
   * to finish processing them.
   */
  static void uinput_flush_requests(struct uinput_device *udev)
  {
  	struct uinput_request *request;
  	int i;
  
  	spin_lock(&udev->requests_lock);
  
  	for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
  		request = udev->requests[i];
  		if (request) {
  			request->retval = -ENODEV;
  			uinput_request_done(udev, request);
  		}
  	}
  
  	spin_unlock(&udev->requests_lock);
  }
  
  static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
  {
  	uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
  }
  
  static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
  {
  	uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
  }
  
  static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
  {
  	return uinput_dev_event(dev, EV_FF, effect_id, value);
  }
  
  static int uinput_dev_upload_effect(struct input_dev *dev,
  				    struct ff_effect *effect,
  				    struct ff_effect *old)
  {
  	struct uinput_device *udev = input_get_drvdata(dev);
  	struct uinput_request request;
  
  	/*
  	 * uinput driver does not currently support periodic effects with
  	 * custom waveform since it does not have a way to pass buffer of
  	 * samples (custom_data) to userspace. If ever there is a device
  	 * supporting custom waveforms we would need to define an additional
  	 * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
  	 */
  	if (effect->type == FF_PERIODIC &&
  			effect->u.periodic.waveform == FF_CUSTOM)
  		return -EINVAL;
  
  	request.code = UI_FF_UPLOAD;
  	request.u.upload.effect = effect;
  	request.u.upload.old = old;
  
  	return uinput_request_submit(udev, &request);
  }
  
  static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
  {
  	struct uinput_device *udev = input_get_drvdata(dev);
  	struct uinput_request request;
  
  	if (!test_bit(EV_FF, dev->evbit))
  		return -ENOSYS;
  
  	request.code = UI_FF_ERASE;
  	request.u.effect_id = effect_id;
  
  	return uinput_request_submit(udev, &request);
  }
  
  static void uinput_destroy_device(struct uinput_device *udev)
  {
  	const char *name, *phys;
  	struct input_dev *dev = udev->dev;
  	enum uinput_state old_state = udev->state;
  
  	udev->state = UIST_NEW_DEVICE;
  
  	if (dev) {
  		name = dev->name;
  		phys = dev->phys;
  		if (old_state == UIST_CREATED) {
  			uinput_flush_requests(udev);
  			input_unregister_device(dev);
  		} else {
  			input_free_device(dev);
  		}
  		kfree(name);
  		kfree(phys);
  		udev->dev = NULL;
  	}
  }
  
  static int uinput_create_device(struct uinput_device *udev)
  {
  	struct input_dev *dev = udev->dev;
  	int error;
  
  	if (udev->state != UIST_SETUP_COMPLETE) {
  		printk(KERN_DEBUG "%s: write device info first
  ", UINPUT_NAME);
  		return -EINVAL;
  	}
  
  	if (udev->ff_effects_max) {
  		error = input_ff_create(dev, udev->ff_effects_max);
  		if (error)
  			goto fail1;
  
  		dev->ff->upload = uinput_dev_upload_effect;
  		dev->ff->erase = uinput_dev_erase_effect;
  		dev->ff->playback = uinput_dev_playback;
  		dev->ff->set_gain = uinput_dev_set_gain;
  		dev->ff->set_autocenter = uinput_dev_set_autocenter;
  	}
  
  	error = input_register_device(udev->dev);
  	if (error)
  		goto fail2;
  
  	udev->state = UIST_CREATED;
  
  	return 0;
  
   fail2:	input_ff_destroy(dev);
   fail1: uinput_destroy_device(udev);
  	return error;
  }
  
  static int uinput_open(struct inode *inode, struct file *file)
  {
  	struct uinput_device *newdev;
  
  	newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
  	if (!newdev)
  		return -ENOMEM;
  
  	mutex_init(&newdev->mutex);
  	spin_lock_init(&newdev->requests_lock);
  	init_waitqueue_head(&newdev->requests_waitq);
  	init_waitqueue_head(&newdev->waitq);
  	newdev->state = UIST_NEW_DEVICE;
  
  	file->private_data = newdev;
  	nonseekable_open(inode, file);
  
  	return 0;
  }
  
  static int uinput_validate_absbits(struct input_dev *dev)
  {
  	unsigned int cnt;
  	int retval = 0;
  
  	for (cnt = 0; cnt < ABS_CNT; cnt++) {
  		int min, max;
  		if (!test_bit(cnt, dev->absbit))
  			continue;
  
  		min = input_abs_get_min(dev, cnt);
  		max = input_abs_get_max(dev, cnt);
  
  		if ((min != 0 || max != 0) && max <= min) {
  			printk(KERN_DEBUG
  				"%s: invalid abs[%02x] min:%d max:%d
  ",
  				UINPUT_NAME, cnt,
  				input_abs_get_min(dev, cnt),
  				input_abs_get_max(dev, cnt));
  			retval = -EINVAL;
  			break;
  		}
  
  		if (input_abs_get_flat(dev, cnt) >
  		    input_abs_get_max(dev, cnt) - input_abs_get_min(dev, cnt)) {
  			printk(KERN_DEBUG
  				"%s: abs_flat #%02x out of range: %d "
  				"(min:%d/max:%d)
  ",
  				UINPUT_NAME, cnt,
  				input_abs_get_flat(dev, cnt),
  				input_abs_get_min(dev, cnt),
  				input_abs_get_max(dev, cnt));
  			retval = -EINVAL;
  			break;
  		}
  	}
  	return retval;
  }
  
  static int uinput_allocate_device(struct uinput_device *udev)
  {
  	udev->dev = input_allocate_device();
  	if (!udev->dev)
  		return -ENOMEM;
  
  	udev->dev->event = uinput_dev_event;
  	input_set_drvdata(udev->dev, udev);
  
  	return 0;
  }
  
  static int uinput_setup_device(struct uinput_device *udev,
  			       const char __user *buffer, size_t count)
  {
  	struct uinput_user_dev	*user_dev;
  	struct input_dev	*dev;
  	int			i;
  	int			retval;
  
  	if (count != sizeof(struct uinput_user_dev))
  		return -EINVAL;
  
  	if (!udev->dev) {
  		retval = uinput_allocate_device(udev);
  		if (retval)
  			return retval;
  	}
  
  	dev = udev->dev;
  
  	user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
  	if (IS_ERR(user_dev))
  		return PTR_ERR(user_dev);
  
  	udev->ff_effects_max = user_dev->ff_effects_max;
  
  	/* Ensure name is filled in */
  	if (!user_dev->name[0]) {
  		retval = -EINVAL;
  		goto exit;
  	}
  
  	kfree(dev->name);
  	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
  			     GFP_KERNEL);
  	if (!dev->name) {
  		retval = -ENOMEM;
  		goto exit;
  	}
  
  	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;
  
  	for (i = 0; i < ABS_CNT; i++) {
  		input_abs_set_max(dev, i, user_dev->absmax[i]);
  		input_abs_set_min(dev, i, user_dev->absmin[i]);
  		input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
  		input_abs_set_flat(dev, i, user_dev->absflat[i]);
  	}
  
  	/* 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)
  			goto exit;
  		if (test_bit(ABS_MT_SLOT, dev->absbit)) {
  			int nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
  			input_mt_init_slots(dev, nslot, 0);
  		} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
  			input_set_events_per_packet(dev, 60);
  		}
  	}
  
  	udev->state = UIST_SETUP_COMPLETE;
  	retval = count;
  
   exit:
  	kfree(user_dev);
  	return retval;
  }
  
  static ssize_t uinput_inject_events(struct uinput_device *udev,
  				    const char __user *buffer, size_t count)
  {
  	struct input_event ev;
  	size_t bytes = 0;
  
  	if (count != 0 && count < input_event_size())
  		return -EINVAL;
  
  	while (bytes + input_event_size() <= count) {
  		/*
  		 * Note that even if some events were fetched successfully
  		 * we are still going to return EFAULT instead of partial
  		 * count to let userspace know that it got it's buffers
  		 * all wrong.
  		 */
  		if (input_event_from_user(buffer + bytes, &ev))
  			return -EFAULT;
  
  		input_event(udev->dev, ev.type, ev.code, ev.value);
  		bytes += input_event_size();
  	}
  
  	return bytes;
  }
  
  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;
  	int retval;
  
  	if (count == 0)
  		return 0;
  
  	retval = mutex_lock_interruptible(&udev->mutex);
  	if (retval)
  		return retval;
  
  	retval = udev->state == UIST_CREATED ?
  			uinput_inject_events(udev, buffer, count) :
  			uinput_setup_device(udev, buffer, count);
  
  	mutex_unlock(&udev->mutex);
  
  	return retval;
  }
  
  static bool uinput_fetch_next_event(struct uinput_device *udev,
  				    struct input_event *event)
  {
  	bool have_event;
  
  	spin_lock_irq(&udev->dev->event_lock);
  
  	have_event = udev->head != udev->tail;
  	if (have_event) {
  		*event = udev->buff[udev->tail];
  		udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
  	}
  
  	spin_unlock_irq(&udev->dev->event_lock);
  
  	return have_event;
  }
  
  static ssize_t uinput_events_to_user(struct uinput_device *udev,
  				     char __user *buffer, size_t count)
  {
  	struct input_event event;
  	size_t read = 0;
  
  	while (read + input_event_size() <= count &&
  	       uinput_fetch_next_event(udev, &event)) {
  
  		if (input_event_to_user(buffer + read, &event))
  			return -EFAULT;
  
  		read += input_event_size();
  	}
  
  	return read;
  }
  
  static ssize_t uinput_read(struct file *file, char __user *buffer,
  			   size_t count, loff_t *ppos)
  {
  	struct uinput_device *udev = file->private_data;
  	ssize_t retval;
  
  	if (count != 0 && count < input_event_size())
  		return -EINVAL;
  
  	do {
  		retval = mutex_lock_interruptible(&udev->mutex);
  		if (retval)
  			return retval;
  
  		if (udev->state != UIST_CREATED)
  			retval = -ENODEV;
  		else if (udev->head == udev->tail &&
  			 (file->f_flags & O_NONBLOCK))
  			retval = -EAGAIN;
  		else
  			retval = uinput_events_to_user(udev, buffer, count);
  
  		mutex_unlock(&udev->mutex);
  
  		if (retval || count == 0)
  			break;
  
  		if (!(file->f_flags & O_NONBLOCK))
  			retval = wait_event_interruptible(udev->waitq,
  						  udev->head != udev->tail ||
  						  udev->state != UIST_CREATED);
  	} while (retval == 0);
  
  	return retval;
  }
  
  static unsigned int uinput_poll(struct file *file, poll_table *wait)
  {
  	struct uinput_device *udev = file->private_data;
  
  	poll_wait(file, &udev->waitq, wait);
  
  	if (udev->head != udev->tail)
  		return POLLIN | POLLRDNORM;
  
  	return 0;
  }
  
  static int uinput_release(struct inode *inode, struct file *file)
  {
  	struct uinput_device *udev = file->private_data;
  
  	uinput_destroy_device(udev);
  	kfree(udev);
  
  	return 0;
  }
  
  #ifdef CONFIG_COMPAT
  struct uinput_ff_upload_compat {
  	__u32			request_id;
  	__s32			retval;
  	struct ff_effect_compat	effect;
  	struct ff_effect_compat	old;
  };
  
  static int uinput_ff_upload_to_user(char __user *buffer,
  				    const struct uinput_ff_upload *ff_up)
  {
  	if (INPUT_COMPAT_TEST) {
  		struct uinput_ff_upload_compat ff_up_compat;
  
  		ff_up_compat.request_id = ff_up->request_id;
  		ff_up_compat.retval = ff_up->retval;
  		/*
  		 * It so happens that the pointer that gives us the trouble
  		 * is the last field in the structure. Since we don't support
  		 * custom waveforms in uinput anyway we can just copy the whole
  		 * thing (to the compat size) and ignore the pointer.
  		 */
  		memcpy(&ff_up_compat.effect, &ff_up->effect,
  			sizeof(struct ff_effect_compat));
  		memcpy(&ff_up_compat.old, &ff_up->old,
  			sizeof(struct ff_effect_compat));
  
  		if (copy_to_user(buffer, &ff_up_compat,
  				 sizeof(struct uinput_ff_upload_compat)))
  			return -EFAULT;
  	} else {
  		if (copy_to_user(buffer, ff_up,
  				 sizeof(struct uinput_ff_upload)))
  			return -EFAULT;
  	}
  
  	return 0;
  }
  
  static int uinput_ff_upload_from_user(const char __user *buffer,
  				      struct uinput_ff_upload *ff_up)
  {
  	if (INPUT_COMPAT_TEST) {
  		struct uinput_ff_upload_compat ff_up_compat;
  
  		if (copy_from_user(&ff_up_compat, buffer,
  				   sizeof(struct uinput_ff_upload_compat)))
  			return -EFAULT;
  
  		ff_up->request_id = ff_up_compat.request_id;
  		ff_up->retval = ff_up_compat.retval;
  		memcpy(&ff_up->effect, &ff_up_compat.effect,
  			sizeof(struct ff_effect_compat));
  		memcpy(&ff_up->old, &ff_up_compat.old,
  			sizeof(struct ff_effect_compat));
  
  	} else {
  		if (copy_from_user(ff_up, buffer,
  				   sizeof(struct uinput_ff_upload)))
  			return -EFAULT;
  	}
  
  	return 0;
  }
  
  #else
  
  static int uinput_ff_upload_to_user(char __user *buffer,
  				    const struct uinput_ff_upload *ff_up)
  {
  	if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
  		return -EFAULT;
  
  	return 0;
  }
  
  static int uinput_ff_upload_from_user(const char __user *buffer,
  				      struct uinput_ff_upload *ff_up)
  {
  	if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
  		return -EFAULT;
  
  	return 0;
  }
  
  #endif
  
  #define uinput_set_bit(_arg, _bit, _max)		\
  ({							\
  	int __ret = 0;					\
  	if (udev->state == UIST_CREATED)		\
  		__ret =  -EINVAL;			\
  	else if ((_arg) > (_max))			\
  		__ret = -EINVAL;			\
  	else set_bit((_arg), udev->dev->_bit);		\
  	__ret;						\
  })
  
  static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
  				 unsigned long arg, void __user *p)
  {
  	int			retval;
  	struct uinput_device	*udev = file->private_data;
  	struct uinput_ff_upload ff_up;
  	struct uinput_ff_erase  ff_erase;
  	struct uinput_request   *req;
  	char			*phys;
  
  	retval = mutex_lock_interruptible(&udev->mutex);
  	if (retval)
  		return retval;
  
  	if (!udev->dev) {
  		retval = uinput_allocate_device(udev);
  		if (retval)
  			goto out;
  	}
  
  	switch (cmd) {
  		case UI_DEV_CREATE:
  			retval = uinput_create_device(udev);
  			break;
  
  		case UI_DEV_DESTROY:
  			uinput_destroy_device(udev);
  			break;
  
  		case UI_SET_EVBIT:
  			retval = uinput_set_bit(arg, evbit, EV_MAX);
  			break;
  
  		case UI_SET_KEYBIT:
  			retval = uinput_set_bit(arg, keybit, KEY_MAX);
  			break;
  
  		case UI_SET_RELBIT:
  			retval = uinput_set_bit(arg, relbit, REL_MAX);
  			break;
  
  		case UI_SET_ABSBIT:
  			retval = uinput_set_bit(arg, absbit, ABS_MAX);
  			break;
  
  		case UI_SET_MSCBIT:
  			retval = uinput_set_bit(arg, mscbit, MSC_MAX);
  			break;
  
  		case UI_SET_LEDBIT:
  			retval = uinput_set_bit(arg, ledbit, LED_MAX);
  			break;
  
  		case UI_SET_SNDBIT:
  			retval = uinput_set_bit(arg, sndbit, SND_MAX);
  			break;
  
  		case UI_SET_FFBIT:
  			retval = uinput_set_bit(arg, ffbit, FF_MAX);
  			break;
  
  		case UI_SET_SWBIT:
  			retval = uinput_set_bit(arg, swbit, SW_MAX);
  			break;
  
  		case UI_SET_PROPBIT:
  			retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
  			break;
  
  		case UI_SET_PHYS:
  			if (udev->state == UIST_CREATED) {
  				retval = -EINVAL;
  				goto out;
  			}
  
  			phys = strndup_user(p, 1024);
  			if (IS_ERR(phys)) {
  				retval = PTR_ERR(phys);
  				goto out;
  			}
  
  			kfree(udev->dev->phys);
  			udev->dev->phys = phys;
  			break;
  
  		case UI_BEGIN_FF_UPLOAD:
  			retval = uinput_ff_upload_from_user(p, &ff_up);
  			if (retval)
  				break;
  
  			req = uinput_request_find(udev, ff_up.request_id);
  			if (!req || req->code != UI_FF_UPLOAD ||
  			    !req->u.upload.effect) {
  				retval = -EINVAL;
  				break;
  			}
  
  			ff_up.retval = 0;
  			ff_up.effect = *req->u.upload.effect;
  			if (req->u.upload.old)
  				ff_up.old = *req->u.upload.old;
  			else
  				memset(&ff_up.old, 0, sizeof(struct ff_effect));
  
  			retval = uinput_ff_upload_to_user(p, &ff_up);
  			break;
  
  		case UI_BEGIN_FF_ERASE:
  			if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
  				retval = -EFAULT;
  				break;
  			}
  
  			req = uinput_request_find(udev, ff_erase.request_id);
  			if (!req || req->code != UI_FF_ERASE) {
  				retval = -EINVAL;
  				break;
  			}
  
  			ff_erase.retval = 0;
  			ff_erase.effect_id = req->u.effect_id;
  			if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
  				retval = -EFAULT;
  				break;
  			}
  
  			break;
  
  		case UI_END_FF_UPLOAD:
  			retval = uinput_ff_upload_from_user(p, &ff_up);
  			if (retval)
  				break;
  
  			req = uinput_request_find(udev, ff_up.request_id);
  			if (!req || req->code != UI_FF_UPLOAD ||
  			    !req->u.upload.effect) {
  				retval = -EINVAL;
  				break;
  			}
  
  			req->retval = ff_up.retval;
  			uinput_request_done(udev, req);
  			break;
  
  		case UI_END_FF_ERASE:
  			if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
  				retval = -EFAULT;
  				break;
  			}
  
  			req = uinput_request_find(udev, ff_erase.request_id);
  			if (!req || req->code != UI_FF_ERASE) {
  				retval = -EINVAL;
  				break;
  			}
  
  			req->retval = ff_erase.retval;
  			uinput_request_done(udev, req);
  			break;
  
  		default:
  			retval = -EINVAL;
  	}
  
   out:
  	mutex_unlock(&udev->mutex);
  	return retval;
  }
  
  static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  {
  	return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
  }
  
  #ifdef CONFIG_COMPAT
  static long uinput_compat_ioctl(struct file *file,
  				unsigned int cmd, unsigned long arg)
  {
  	return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
  }
  #endif
  
  static const struct file_operations uinput_fops = {
  	.owner		= THIS_MODULE,
  	.open		= uinput_open,
  	.release	= uinput_release,
  	.read		= uinput_read,
  	.write		= uinput_write,
  	.poll		= uinput_poll,
  	.unlocked_ioctl	= uinput_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= uinput_compat_ioctl,
  #endif
  	.llseek		= no_llseek,
  };
  
  static struct miscdevice uinput_misc = {
  	.fops		= &uinput_fops,
  	.minor		= UINPUT_MINOR,
  	.name		= UINPUT_NAME,
  };
  MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
  MODULE_ALIAS("devname:" 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_VERSION("0.3");
  
  module_init(uinput_init);
  module_exit(uinput_exit);