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Commit 509ca1a9 authored by Anssi Hannula's avatar Anssi Hannula Committed by Dmitry Torokhov
Browse files

Input: implement new force feedback interface 



Implement a new force feedback interface, in which all non-driver-specific
operations are separated to a common module. This includes handling effect
type validations, locking, etc.

The effects are now file descriptor specific instead of the previous strange
half-process half-fd specific behaviour. The effect memory of devices is not
emptied if the root user opens and closes the device while another user is
using effects. This is a minor change and most likely no force feedback
aware programs are affected by this negatively.

Otherwise the userspace interface is left unaltered.

Signed-off-by: default avatarAnssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 806d41b7

drivers/input/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
# Each configuration option enables a list of files.



obj-$(CONFIG_INPUT)		+= input-core.o

input-core-objs := input.o

input-core-objs := input.o ff-core.o



obj-$(CONFIG_INPUT_MOUSEDEV)	+= mousedev.o

obj-$(CONFIG_INPUT_JOYDEV)	+= joydev.o

drivers/input/evdev.c

+15 −17
Original line number Diff line number Diff line
@@ -391,8 +391,10 @@ static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 
	struct evdev *evdev = list->evdev;

	struct input_dev *dev = evdev->handle.dev;

	struct input_absinfo abs;

	struct ff_effect effect;

	int __user *ip = (int __user *)p;

	int i, t, u, v;

	int error;



	if (!evdev->exist)

		return -ENODEV;
@@ -460,27 +462,22 @@ static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 
			return 0;



		case EVIOCSFF:

			if (dev->upload_effect) {

				struct ff_effect effect;

				int err;



			if (copy_from_user(&effect, p, sizeof(effect)))

				return -EFAULT;

				err = dev->upload_effect(dev, &effect);



			error = input_ff_upload(dev, &effect, file);



			if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))

				return -EFAULT;

				return err;

			} else

				return -ENOSYS;



		case EVIOCRMFF:

			if (!dev->erase_effect)

				return -ENOSYS;

			return error;



			return dev->erase_effect(dev, (int)(unsigned long) p);

		case EVIOCRMFF:

			return input_ff_erase(dev, (int)(unsigned long) p, file);



		case EVIOCGEFFECTS:

			if (put_user(dev->ff_effects_max, ip))

			i = test_bit(EV_FF, dev->evbit) ? dev->ff->max_effects : 0;

			if (put_user(i, ip))

				return -EFAULT;

			return 0;
@@ -669,6 +666,7 @@ static void evdev_disconnect(struct input_handle *handle) 
	evdev->exist = 0;



	if (evdev->open) {

		input_flush_device(handle, NULL);

		input_close_device(handle);

		wake_up_interruptible(&evdev->wait);

		list_for_each_entry(list, &evdev->list, node)

drivers/input/ff-core.c

0 → 100644
+367 −0
Original line number Diff line number Diff line 
/*

 *  Force feedback support for Linux input subsystem

 *

 *  Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>

 *  Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>

 */



/*

 * 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

 */



/* #define DEBUG */



#define debug(format, arg...) pr_debug("ff-core: " format "\n", ## arg)



#include <linux/input.h>

#include <linux/module.h>

#include <linux/mutex.h>



/*

 * Check that the effect_id is a valid effect and whether the user

 * is the owner

 */

static int check_effect_access(struct ff_device *ff, int effect_id,

				struct file *file)

{

	if (effect_id < 0 || effect_id >= ff->max_effects ||

	    !ff->effect_owners[effect_id])

		return -EINVAL;



	if (file && ff->effect_owners[effect_id] != file)

		return -EACCES;



	return 0;

}



/*

 * Checks whether 2 effects can be combined together

 */

static inline int check_effects_compatible(struct ff_effect *e1,

					   struct ff_effect *e2)

{

	return e1->type == e2->type &&

	       (e1->type != FF_PERIODIC ||

		e1->u.periodic.waveform == e2->u.periodic.waveform);

}



/*

 * Convert an effect into compatible one

 */

static int compat_effect(struct ff_device *ff, struct ff_effect *effect)

{

	int magnitude;



	switch (effect->type) {

	case FF_RUMBLE:

		if (!test_bit(FF_PERIODIC, ff->ffbit))

			return -EINVAL;



		/*

		 * calculate manginude of sine wave as average of rumble's

		 * 2/3 of strong magnitude and 1/3 of weak magnitude

		 */

		magnitude = effect->u.rumble.strong_magnitude / 3 +

			    effect->u.rumble.weak_magnitude / 6;



		effect->type = FF_PERIODIC;

		effect->u.periodic.waveform = FF_SINE;

		effect->u.periodic.period = 50;

		effect->u.periodic.magnitude = max(magnitude, 0x7fff);

		effect->u.periodic.offset = 0;

		effect->u.periodic.phase = 0;

		effect->u.periodic.envelope.attack_length = 0;

		effect->u.periodic.envelope.attack_level = 0;

		effect->u.periodic.envelope.fade_length = 0;

		effect->u.periodic.envelope.fade_level = 0;



		return 0;



	default:

		/* Let driver handle conversion */

		return 0;

	}

}



/**

 * input_ff_upload() - upload effect into force-feedback device

 * @dev: input device

 * @effect: effect to be uploaded

 * @file: owner of the effect

 */

int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,

		    struct file *file)

{

	struct ff_device *ff = dev->ff;

	struct ff_effect *old;

	int ret = 0;

	int id;



	if (!test_bit(EV_FF, dev->evbit))

		return -ENOSYS;



	if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||

	    !test_bit(effect->type, dev->ffbit)) {

		debug("invalid or not supported effect type in upload");

		return -EINVAL;

	}



	if (effect->type == FF_PERIODIC &&

	    (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||

	     effect->u.periodic.waveform > FF_WAVEFORM_MAX ||

	     !test_bit(effect->u.periodic.waveform, dev->ffbit))) {

		debug("invalid or not supported wave form in upload");

		return -EINVAL;

	}



	if (!test_bit(effect->type, ff->ffbit)) {

		ret = compat_effect(ff, effect);

		if (ret)

			return ret;

	}



	mutex_lock(&ff->mutex);



	if (effect->id == -1) {

		for (id = 0; id < ff->max_effects; id++)

		     if (!ff->effect_owners[id])

			break;



		if (id >= ff->max_effects) {

			ret = -ENOSPC;

			goto out;

		}



		effect->id = id;

		old = NULL;



	} else {

		id = effect->id;



		ret = check_effect_access(ff, id, file);

		if (ret)

			goto out;



		old = &ff->effects[id];



		if (!check_effects_compatible(effect, old)) {

			ret = -EINVAL;

			goto out;

		}

	}



	ret = ff->upload(dev, effect, old);

	if (ret)

		goto out;



	ff->effects[id] = *effect;

	ff->effect_owners[id] = file;



 out:

	mutex_unlock(&ff->mutex);

	return ret;

}

EXPORT_SYMBOL_GPL(input_ff_upload);



/*

 * Erases the effect if the requester is also the effect owner. The mutex

 * should already be locked before calling this function.

 */

static int erase_effect(struct input_dev *dev, int effect_id,

			struct file *file)

{

	struct ff_device *ff = dev->ff;

	int error;



	error = check_effect_access(ff, effect_id, file);

	if (error)

		return error;



	ff->playback(dev, effect_id, 0);



	if (ff->erase) {

		error = ff->erase(dev, effect_id);

		if (error)

			return error;

	}



	ff->effect_owners[effect_id] = NULL;



	return 0;

}



/**

 * input_ff_erase - erase an effect from device

 * @dev: input device to erase effect from

 * @effect_id: id of the ffect to be erased

 * @file: purported owner of the request

 *

 * This function erases a force-feedback effect from specified device.

 * The effect will only be erased if it was uploaded through the same

 * file handle that is requesting erase.

 */

int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)

{

	struct ff_device *ff = dev->ff;

	int ret;



	if (!test_bit(EV_FF, dev->evbit))

		return -ENOSYS;



	mutex_lock(&ff->mutex);

	ret = erase_effect(dev, effect_id, file);

	mutex_unlock(&ff->mutex);



	return ret;

}

EXPORT_SYMBOL_GPL(input_ff_erase);



/*

 * flush_effects - erase all effects owned by a file handle

 */

static int flush_effects(struct input_dev *dev, struct file *file)

{

	struct ff_device *ff = dev->ff;

	int i;



	debug("flushing now");



	mutex_lock(&ff->mutex);



	for (i = 0; i < ff->max_effects; i++)

		erase_effect(dev, i, file);



	mutex_unlock(&ff->mutex);



	return 0;

}



/**

 * input_ff_event() - generic handler for force-feedback events

 * @dev: input device to send the effect to

 * @type: event type (anything but EV_FF is ignored)

 * @code: event code

 * @value: event value

 */

int input_ff_event(struct input_dev *dev, unsigned int type,

		   unsigned int code, int value)

{

	struct ff_device *ff = dev->ff;



	if (type != EV_FF)

		return 0;



	mutex_lock(&ff->mutex);



	switch (code) {

	case FF_GAIN:

		if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff)

			break;



		ff->set_gain(dev, value);

		break;



	case FF_AUTOCENTER:

		if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffff)

			break;



		ff->set_autocenter(dev, value);

		break;



	default:

		ff->playback(dev, code, value);

		break;

	}



	mutex_unlock(&ff->mutex);

	return 0;

}

EXPORT_SYMBOL_GPL(input_ff_event);



/**

 * input_ff_create() - create force-feedback device

 * @dev: input device supporting force-feedback

 * @max_effects: maximum number of effects supported by the device

 *

 * This function allocates all necessary memory for a force feedback

 * portion of an input device and installs all default handlers.

 * @dev->ffbit should be already set up before calling this function.

 * Once ff device is created you need to setup its upload, erase,

 * playback and other handlers before registering input device

 */

int input_ff_create(struct input_dev *dev, int max_effects)

{

	struct ff_device *ff;

	int i;



	if (!max_effects) {

		printk(KERN_ERR

		       "ff-core: cannot allocate device without any effects\n");

		return -EINVAL;

	}



	ff = kzalloc(sizeof(struct ff_device) +

		     max_effects * sizeof(struct file *), GFP_KERNEL);

	if (!ff)

		return -ENOMEM;



	ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),

			      GFP_KERNEL);

	if (!ff->effects) {

		kfree(ff);

		return -ENOMEM;

	}



	ff->max_effects = max_effects;

	mutex_init(&ff->mutex);



	dev->ff = ff;

	dev->flush = flush_effects;

	dev->event = input_ff_event;

	set_bit(EV_FF, dev->evbit);



	/* Copy "true" bits into ff device bitmap */

	for (i = 0; i <= FF_MAX; i++)

		if (test_bit(i, dev->ffbit))

			set_bit(i, ff->ffbit);



	/* we can emulate RUMBLE with periodic effects */

	if (test_bit(FF_PERIODIC, ff->ffbit))

		set_bit(FF_RUMBLE, dev->ffbit);



	return 0;

}

EXPORT_SYMBOL_GPL(input_ff_create);



/**

 * input_ff_free() - frees force feedback portion of input device

 * @dev: input device supporintg force feedback

 *

 * This function is only needed in error path as input core will

 * automatically free force feedback structures when device is

 * destroyed.

 */

void input_ff_destroy(struct input_dev *dev)

{

	clear_bit(EV_FF, dev->evbit);

	if (dev->ff) {

		if (dev->ff->destroy)

			dev->ff->destroy(dev->ff);

		kfree(dev->ff->private);

		kfree(dev->ff);

		dev->ff = NULL;

	}

}

EXPORT_SYMBOL_GPL(input_ff_destroy);

drivers/input/input.c

+6 −0
Original line number Diff line number Diff line
@@ -176,6 +176,10 @@ void input_event(struct input_dev *dev, unsigned int type, unsigned int code, in 
			break;



		case EV_FF:



			if (value < 0)

				return;



			if (dev->event)

				dev->event(dev, type, code, value);

			break;
@@ -762,7 +766,9 @@ static void input_dev_release(struct class_device *class_dev) 
{

	struct input_dev *dev = to_input_dev(class_dev);



	input_ff_destroy(dev);

	kfree(dev);



	module_put(THIS_MODULE);

}

include/linux/input.h

+61 −0
Original line number Diff line number Diff line
@@ -784,6 +784,9 @@ struct ff_effect { 
#define FF_INERTIA	0x56

#define FF_RAMP		0x57



#define FF_EFFECT_MIN	FF_RUMBLE

#define FF_EFFECT_MAX	FF_RAMP



/*

 * Force feedback periodic effect types

 */
@@ -795,6 +798,9 @@ struct ff_effect { 
#define FF_SAW_DOWN	0x5c

#define FF_CUSTOM	0x5d



#define FF_WAVEFORM_MIN	FF_SQUARE

#define FF_WAVEFORM_MAX	FF_CUSTOM



/*

 * Set ff device properties

 */
@@ -870,6 +876,8 @@ struct input_dev { 
	unsigned int keycodesize;

	void *keycode;



	struct ff_device *ff;



	unsigned int repeat_key;

	struct timer_list timer;
@@ -1108,5 +1116,58 @@ static inline void input_set_abs_params(struct input_dev *dev, int axis, int min 


extern struct class input_class;



/**

 * struct ff_device - force-feedback part of an input device

 * @upload: Called to upload an new effect into device

 * @erase: Called to erase an effect from device

 * @playback: Called to request device to start playing specified effect

 * @set_gain: Called to set specified gain

 * @set_autocenter: Called to auto-center device

 * @destroy: called by input core when parent input device is being

 *	destroyed

 * @private: driver-specific data, will be freed automatically

 * @ffbit: bitmap of force feedback capabilities truly supported by

 *	device (not emulated like ones in input_dev->ffbit)

 * @mutex: mutex for serializing access to the device

 * @max_effects: maximum number of effects supported by device

 * @effects: pointer to an array of effects currently loaded into device

 * @effect_owners: array of effect owners; when file handle owning

 *	an effect gets closed the effcet is automatically erased

 *

 * Every force-feedback device must implement upload() and playback()

 * methods; erase() is optional. set_gain() and set_autocenter() need

 * only be implemented if driver sets up FF_GAIN and FF_AUTOCENTER

 * bits.

 */

struct ff_device {

	int (*upload)(struct input_dev *dev, struct ff_effect *effect,

		      struct ff_effect *old);

	int (*erase)(struct input_dev *dev, int effect_id);



	int (*playback)(struct input_dev *dev, int effect_id, int value);

	void (*set_gain)(struct input_dev *dev, u16 gain);

	void (*set_autocenter)(struct input_dev *dev, u16 magnitude);



	void (*destroy)(struct ff_device *);



	void *private;



	unsigned long ffbit[NBITS(FF_MAX)];



	struct mutex mutex;



	int max_effects;

	struct ff_effect *effects;

	struct file *effect_owners[];

};



int input_ff_create(struct input_dev *dev, int max_effects);

void input_ff_destroy(struct input_dev *dev);



int input_ff_event(struct input_dev *dev, unsigned int type, unsigned int code, int value);



int input_ff_upload(struct input_dev *dev, struct ff_effect *effect, struct file *file);

int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file);



#endif

#endif