uinput.c

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/*
 *  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 <[e-mail]>
 *
 * Changes/Revisions:
 *	0.3	09/04/2006 (Anssi Hannula <[e-mail]>)
 *		- updated ff support for the changes in kernel interface
 *		- added MODULE_VERSION
 *	0.2	16/10/2004 (Micah Dowty <[e-mail]>)
 *		- added force feedback support
 *              - added UI_SET_PHYS
 *	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/smp_lock.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uinput.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;
}

static int uinput_request_alloc_id(struct uinput_device *udev, struct uinput_request *request)
{
	/* Atomically allocate an ID for the given request. Returns 0 on success. */
	int id;
	int err = -1;

	spin_lock(&udev->requests_lock);

	for (id = 0; id < UINPUT_NUM_REQUESTS; id++)
		if (!udev->requests[id]) {
			request->id = id;
			udev->requests[id] = request;
			err = 0;
			break;
		}

	spin_unlock(&udev->requests_lock);
	return err;
}

static struct uinput_request* uinput_request_find(struct uinput_device *udev, int id)
{
	/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
	if (id >= UINPUT_NUM_REQUESTS || id < 0)
		return NULL;
	return udev->requests[id];
}

static inline 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_submit(struct input_dev *dev, struct uinput_request *request)
{
	/* Tell our userspace app about this new request by queueing an input event */
	uinput_dev_event(dev, EV_UINPUT, request->code, request->id);

	/* Wait for the request to complete */
	wait_for_completion(&request->done);
	return request->retval;
}

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_request request;
	int retval;

	request.id = -1;
	init_completion(&request.done);
	request.code = UI_FF_UPLOAD;
	request.u.upload.effect = effect;
	request.u.upload.old = old;

	retval = uinput_request_reserve_slot(input_get_drvdata(dev), &request);
	if (!retval)
		retval = uinput_request_submit(dev, &request);

	return retval;
}

static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
{
	struct uinput_request request;
	int retval;

	if (!test_bit(EV_FF, dev->evbit))
		return -ENOSYS;

	request.id = -1;
	init_completion(&request.done);
	request.code = UI_FF_ERASE;
	request.u.effect_id = effect_id;

	retval = uinput_request_reserve_slot(input_get_drvdata(dev), &request);
	if (!retval)
		retval = uinput_request_submit(dev, &request);

	return retval;
}

static void uinput_destroy_device(struct uinput_device *udev)
{
	const char *name, *phys;

	if (udev->dev) {
		name = udev->dev->name;
		phys = udev->dev->phys;
		if (udev->state == UIST_CREATED)
			input_unregister_device(udev->dev);
		else
			input_free_device(udev->dev);
		kfree(name);
		kfree(phys);
		udev->dev = NULL;
	}

	udev->state = UIST_NEW_DEVICE;
}

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\n", 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;

	return 0;
}

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

	for (cnt = 0; cnt < ABS_MAX + 1; cnt++) {
		if (!test_bit(cnt, dev->absbit))
			continue;

		if ((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->absmax[cnt] - dev->absmin[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_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;
	char			*name;
	int			size;
	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 = kmalloc(sizeof(struct uinput_user_dev), GFP_KERNEL);
	if (!user_dev)
		return -ENOMEM;

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

	udev->ff_effects_max = user_dev->ff_effects_max;

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

	kfree(dev->name);
	dev->name = name = kmalloc(size, GFP_KERNEL);
	if (!name) {
		retval = -ENOMEM;
		goto exit;
	}
	strlcpy(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;

	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);