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379 lines
8.7 KiB
379 lines
8.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Force feedback support for Linux input subsystem |
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* |
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* Copyright (c) 2006 Anssi Hannula <[email protected]> |
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* Copyright (c) 2006 Dmitry Torokhov <[email protected]> |
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*/ |
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/* |
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*/ |
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/* #define DEBUG */ |
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#include <linux/input.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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/* |
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* Check that the effect_id is a valid effect and whether the user |
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* is the owner |
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*/ |
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static int check_effect_access(struct ff_device *ff, int effect_id, |
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struct file *file) |
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{ |
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if (effect_id < 0 || effect_id >= ff->max_effects || |
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!ff->effect_owners[effect_id]) |
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return -EINVAL; |
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if (file && ff->effect_owners[effect_id] != file) |
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return -EACCES; |
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return 0; |
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} |
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/* |
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* Checks whether 2 effects can be combined together |
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*/ |
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static inline int check_effects_compatible(struct ff_effect *e1, |
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struct ff_effect *e2) |
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{ |
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return e1->type == e2->type && |
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(e1->type != FF_PERIODIC || |
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e1->u.periodic.waveform == e2->u.periodic.waveform); |
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} |
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/* |
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* Convert an effect into compatible one |
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*/ |
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static int compat_effect(struct ff_device *ff, struct ff_effect *effect) |
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{ |
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int magnitude; |
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switch (effect->type) { |
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case FF_RUMBLE: |
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if (!test_bit(FF_PERIODIC, ff->ffbit)) |
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return -EINVAL; |
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/* |
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* calculate magnitude of sine wave as average of rumble's |
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* 2/3 of strong magnitude and 1/3 of weak magnitude |
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*/ |
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magnitude = effect->u.rumble.strong_magnitude / 3 + |
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effect->u.rumble.weak_magnitude / 6; |
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effect->type = FF_PERIODIC; |
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effect->u.periodic.waveform = FF_SINE; |
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effect->u.periodic.period = 50; |
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effect->u.periodic.magnitude = max(magnitude, 0x7fff); |
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effect->u.periodic.offset = 0; |
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effect->u.periodic.phase = 0; |
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effect->u.periodic.envelope.attack_length = 0; |
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effect->u.periodic.envelope.attack_level = 0; |
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effect->u.periodic.envelope.fade_length = 0; |
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effect->u.periodic.envelope.fade_level = 0; |
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return 0; |
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default: |
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/* Let driver handle conversion */ |
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return 0; |
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} |
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} |
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/** |
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* input_ff_upload() - upload effect into force-feedback device |
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* @dev: input device |
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* @effect: effect to be uploaded |
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* @file: owner of the effect |
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*/ |
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int input_ff_upload(struct input_dev *dev, struct ff_effect *effect, |
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struct file *file) |
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{ |
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struct ff_device *ff = dev->ff; |
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struct ff_effect *old; |
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int ret = 0; |
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int id; |
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if (!test_bit(EV_FF, dev->evbit)) |
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return -ENOSYS; |
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if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX || |
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!test_bit(effect->type, dev->ffbit)) { |
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dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n"); |
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return -EINVAL; |
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} |
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if (effect->type == FF_PERIODIC && |
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(effect->u.periodic.waveform < FF_WAVEFORM_MIN || |
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effect->u.periodic.waveform > FF_WAVEFORM_MAX || |
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!test_bit(effect->u.periodic.waveform, dev->ffbit))) { |
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dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n"); |
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return -EINVAL; |
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} |
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if (!test_bit(effect->type, ff->ffbit)) { |
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ret = compat_effect(ff, effect); |
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if (ret) |
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return ret; |
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} |
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mutex_lock(&ff->mutex); |
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if (effect->id == -1) { |
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for (id = 0; id < ff->max_effects; id++) |
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if (!ff->effect_owners[id]) |
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break; |
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if (id >= ff->max_effects) { |
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ret = -ENOSPC; |
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goto out; |
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} |
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effect->id = id; |
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old = NULL; |
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} else { |
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id = effect->id; |
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ret = check_effect_access(ff, id, file); |
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if (ret) |
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goto out; |
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old = &ff->effects[id]; |
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if (!check_effects_compatible(effect, old)) { |
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ret = -EINVAL; |
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goto out; |
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} |
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} |
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ret = ff->upload(dev, effect, old); |
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if (ret) |
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goto out; |
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spin_lock_irq(&dev->event_lock); |
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ff->effects[id] = *effect; |
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ff->effect_owners[id] = file; |
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spin_unlock_irq(&dev->event_lock); |
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out: |
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mutex_unlock(&ff->mutex); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(input_ff_upload); |
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/* |
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* Erases the effect if the requester is also the effect owner. The mutex |
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* should already be locked before calling this function. |
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*/ |
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static int erase_effect(struct input_dev *dev, int effect_id, |
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struct file *file) |
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{ |
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struct ff_device *ff = dev->ff; |
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int error; |
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error = check_effect_access(ff, effect_id, file); |
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if (error) |
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return error; |
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spin_lock_irq(&dev->event_lock); |
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ff->playback(dev, effect_id, 0); |
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ff->effect_owners[effect_id] = NULL; |
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spin_unlock_irq(&dev->event_lock); |
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if (ff->erase) { |
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error = ff->erase(dev, effect_id); |
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if (error) { |
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spin_lock_irq(&dev->event_lock); |
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ff->effect_owners[effect_id] = file; |
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spin_unlock_irq(&dev->event_lock); |
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return error; |
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} |
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} |
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return 0; |
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} |
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/** |
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* input_ff_erase - erase a force-feedback effect from device |
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* @dev: input device to erase effect from |
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* @effect_id: id of the effect to be erased |
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* @file: purported owner of the request |
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* |
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* This function erases a force-feedback effect from specified device. |
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* The effect will only be erased if it was uploaded through the same |
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* file handle that is requesting erase. |
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*/ |
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int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file) |
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{ |
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struct ff_device *ff = dev->ff; |
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int ret; |
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if (!test_bit(EV_FF, dev->evbit)) |
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return -ENOSYS; |
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mutex_lock(&ff->mutex); |
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ret = erase_effect(dev, effect_id, file); |
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mutex_unlock(&ff->mutex); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(input_ff_erase); |
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/* |
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* input_ff_flush - erase all effects owned by a file handle |
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* @dev: input device to erase effect from |
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* @file: purported owner of the effects |
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* |
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* This function erases all force-feedback effects associated with |
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* the given owner from specified device. Note that @file may be %NULL, |
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* in which case all effects will be erased. |
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*/ |
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int input_ff_flush(struct input_dev *dev, struct file *file) |
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{ |
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struct ff_device *ff = dev->ff; |
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int i; |
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dev_dbg(&dev->dev, "flushing now\n"); |
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mutex_lock(&ff->mutex); |
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for (i = 0; i < ff->max_effects; i++) |
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erase_effect(dev, i, file); |
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mutex_unlock(&ff->mutex); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(input_ff_flush); |
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/** |
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* input_ff_event() - generic handler for force-feedback events |
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* @dev: input device to send the effect to |
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* @type: event type (anything but EV_FF is ignored) |
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* @code: event code |
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* @value: event value |
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*/ |
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int input_ff_event(struct input_dev *dev, unsigned int type, |
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unsigned int code, int value) |
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{ |
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struct ff_device *ff = dev->ff; |
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if (type != EV_FF) |
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return 0; |
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switch (code) { |
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case FF_GAIN: |
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if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU) |
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break; |
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ff->set_gain(dev, value); |
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break; |
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case FF_AUTOCENTER: |
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if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU) |
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break; |
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ff->set_autocenter(dev, value); |
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break; |
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default: |
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if (check_effect_access(ff, code, NULL) == 0) |
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ff->playback(dev, code, value); |
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break; |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(input_ff_event); |
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/** |
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* input_ff_create() - create force-feedback device |
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* @dev: input device supporting force-feedback |
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* @max_effects: maximum number of effects supported by the device |
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* |
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* This function allocates all necessary memory for a force feedback |
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* portion of an input device and installs all default handlers. |
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* @dev->ffbit should be already set up before calling this function. |
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* Once ff device is created you need to setup its upload, erase, |
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* playback and other handlers before registering input device |
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*/ |
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int input_ff_create(struct input_dev *dev, unsigned int max_effects) |
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{ |
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struct ff_device *ff; |
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size_t ff_dev_size; |
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int i; |
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if (!max_effects) { |
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dev_err(&dev->dev, "cannot allocate device without any effects\n"); |
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return -EINVAL; |
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} |
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if (max_effects > FF_MAX_EFFECTS) { |
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dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n"); |
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return -EINVAL; |
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} |
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ff_dev_size = sizeof(struct ff_device) + |
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max_effects * sizeof(struct file *); |
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if (ff_dev_size < max_effects) /* overflow */ |
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return -EINVAL; |
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ff = kzalloc(ff_dev_size, GFP_KERNEL); |
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if (!ff) |
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return -ENOMEM; |
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ff->effects = kcalloc(max_effects, sizeof(struct ff_effect), |
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GFP_KERNEL); |
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if (!ff->effects) { |
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kfree(ff); |
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return -ENOMEM; |
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} |
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ff->max_effects = max_effects; |
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mutex_init(&ff->mutex); |
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dev->ff = ff; |
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dev->flush = input_ff_flush; |
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dev->event = input_ff_event; |
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__set_bit(EV_FF, dev->evbit); |
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/* Copy "true" bits into ff device bitmap */ |
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for_each_set_bit(i, dev->ffbit, FF_CNT) |
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__set_bit(i, ff->ffbit); |
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/* we can emulate RUMBLE with periodic effects */ |
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if (test_bit(FF_PERIODIC, ff->ffbit)) |
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__set_bit(FF_RUMBLE, dev->ffbit); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(input_ff_create); |
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/** |
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* input_ff_destroy() - frees force feedback portion of input device |
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* @dev: input device supporting force feedback |
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* |
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* This function is only needed in error path as input core will |
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* automatically free force feedback structures when device is |
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* destroyed. |
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*/ |
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void input_ff_destroy(struct input_dev *dev) |
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{ |
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struct ff_device *ff = dev->ff; |
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__clear_bit(EV_FF, dev->evbit); |
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if (ff) { |
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if (ff->destroy) |
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ff->destroy(ff); |
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kfree(ff->private); |
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kfree(ff->effects); |
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kfree(ff); |
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dev->ff = NULL; |
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} |
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} |
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EXPORT_SYMBOL_GPL(input_ff_destroy);
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