From 509ca1a9383601fdc5612d3d3ba5b981f6eb6c8b Mon Sep 17 00:00:00 2001 From: Anssi Hannula Date: Wed, 19 Jul 2006 01:40:22 -0400 Subject: 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: Anssi Hannula Signed-off-by: Dmitry Torokhov --- drivers/input/ff-core.c | 367 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 367 insertions(+) create mode 100644 drivers/input/ff-core.c (limited to 'drivers/input/ff-core.c') diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c new file mode 100644 index 00000000000..35656cadc91 --- /dev/null +++ b/drivers/input/ff-core.c @@ -0,0 +1,367 @@ +/* + * Force feedback support for Linux input subsystem + * + * Copyright (c) 2006 Anssi Hannula + * Copyright (c) 2006 Dmitry Torokhov + */ + +/* + * 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 +#include +#include + +/* + * 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); -- cgit v1.2.3-18-g5258