Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Force feedback support for Linux input subsystem
4 *
5 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
6 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
7 */
8
9/*
10 */
11
12/* #define DEBUG */
13
14#include <linux/input.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19
20/*
21 * Check that the effect_id is a valid effect and whether the user
22 * is the owner
23 */
24static int check_effect_access(struct ff_device *ff, int effect_id,
25 struct file *file)
26{
27 if (effect_id < 0 || effect_id >= ff->max_effects ||
28 !ff->effect_owners[effect_id])
29 return -EINVAL;
30
31 if (file && ff->effect_owners[effect_id] != file)
32 return -EACCES;
33
34 return 0;
35}
36
37/*
38 * Checks whether 2 effects can be combined together
39 */
40static inline int check_effects_compatible(struct ff_effect *e1,
41 struct ff_effect *e2)
42{
43 return e1->type == e2->type &&
44 (e1->type != FF_PERIODIC ||
45 e1->u.periodic.waveform == e2->u.periodic.waveform);
46}
47
48/*
49 * Convert an effect into compatible one
50 */
51static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
52{
53 int magnitude;
54
55 switch (effect->type) {
56 case FF_RUMBLE:
57 if (!test_bit(FF_PERIODIC, ff->ffbit))
58 return -EINVAL;
59
60 /*
61 * calculate magnitude of sine wave as average of rumble's
62 * 2/3 of strong magnitude and 1/3 of weak magnitude
63 */
64 magnitude = effect->u.rumble.strong_magnitude / 3 +
65 effect->u.rumble.weak_magnitude / 6;
66
67 effect->type = FF_PERIODIC;
68 effect->u.periodic.waveform = FF_SINE;
69 effect->u.periodic.period = 50;
70 effect->u.periodic.magnitude = max(magnitude, 0x7fff);
71 effect->u.periodic.offset = 0;
72 effect->u.periodic.phase = 0;
73 effect->u.periodic.envelope.attack_length = 0;
74 effect->u.periodic.envelope.attack_level = 0;
75 effect->u.periodic.envelope.fade_length = 0;
76 effect->u.periodic.envelope.fade_level = 0;
77
78 return 0;
79
80 default:
81 /* Let driver handle conversion */
82 return 0;
83 }
84}
85
86/**
87 * input_ff_upload() - upload effect into force-feedback device
88 * @dev: input device
89 * @effect: effect to be uploaded
90 * @file: owner of the effect
91 */
92int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
93 struct file *file)
94{
95 struct ff_device *ff = dev->ff;
96 struct ff_effect *old;
97 int ret = 0;
98 int id;
99
100 if (!test_bit(EV_FF, dev->evbit))
101 return -ENOSYS;
102
103 if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
104 !test_bit(effect->type, dev->ffbit)) {
105 dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
106 return -EINVAL;
107 }
108
109 if (effect->type == FF_PERIODIC &&
110 (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
111 effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
112 !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
113 dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
114 return -EINVAL;
115 }
116
117 if (!test_bit(effect->type, ff->ffbit)) {
118 ret = compat_effect(ff, effect);
119 if (ret)
120 return ret;
121 }
122
123 mutex_lock(&ff->mutex);
124
125 if (effect->id == -1) {
126 for (id = 0; id < ff->max_effects; id++)
127 if (!ff->effect_owners[id])
128 break;
129
130 if (id >= ff->max_effects) {
131 ret = -ENOSPC;
132 goto out;
133 }
134
135 effect->id = id;
136 old = NULL;
137
138 } else {
139 id = effect->id;
140
141 ret = check_effect_access(ff, id, file);
142 if (ret)
143 goto out;
144
145 old = &ff->effects[id];
146
147 if (!check_effects_compatible(effect, old)) {
148 ret = -EINVAL;
149 goto out;
150 }
151 }
152
153 ret = ff->upload(dev, effect, old);
154 if (ret)
155 goto out;
156
157 spin_lock_irq(&dev->event_lock);
158 ff->effects[id] = *effect;
159 ff->effect_owners[id] = file;
160 spin_unlock_irq(&dev->event_lock);
161
162 out:
163 mutex_unlock(&ff->mutex);
164 return ret;
165}
166EXPORT_SYMBOL_GPL(input_ff_upload);
167
168/*
169 * Erases the effect if the requester is also the effect owner. The mutex
170 * should already be locked before calling this function.
171 */
172static int erase_effect(struct input_dev *dev, int effect_id,
173 struct file *file)
174{
175 struct ff_device *ff = dev->ff;
176 int error;
177
178 error = check_effect_access(ff, effect_id, file);
179 if (error)
180 return error;
181
182 spin_lock_irq(&dev->event_lock);
183 ff->playback(dev, effect_id, 0);
184 ff->effect_owners[effect_id] = NULL;
185 spin_unlock_irq(&dev->event_lock);
186
187 if (ff->erase) {
188 error = ff->erase(dev, effect_id);
189 if (error) {
190 spin_lock_irq(&dev->event_lock);
191 ff->effect_owners[effect_id] = file;
192 spin_unlock_irq(&dev->event_lock);
193
194 return error;
195 }
196 }
197
198 return 0;
199}
200
201/**
202 * input_ff_erase - erase a force-feedback effect from device
203 * @dev: input device to erase effect from
204 * @effect_id: id of the effect to be erased
205 * @file: purported owner of the request
206 *
207 * This function erases a force-feedback effect from specified device.
208 * The effect will only be erased if it was uploaded through the same
209 * file handle that is requesting erase.
210 */
211int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
212{
213 struct ff_device *ff = dev->ff;
214 int ret;
215
216 if (!test_bit(EV_FF, dev->evbit))
217 return -ENOSYS;
218
219 mutex_lock(&ff->mutex);
220 ret = erase_effect(dev, effect_id, file);
221 mutex_unlock(&ff->mutex);
222
223 return ret;
224}
225EXPORT_SYMBOL_GPL(input_ff_erase);
226
227/*
228 * input_ff_flush - erase all effects owned by a file handle
229 * @dev: input device to erase effect from
230 * @file: purported owner of the effects
231 *
232 * This function erases all force-feedback effects associated with
233 * the given owner from specified device. Note that @file may be %NULL,
234 * in which case all effects will be erased.
235 */
236int input_ff_flush(struct input_dev *dev, struct file *file)
237{
238 struct ff_device *ff = dev->ff;
239 int i;
240
241 dev_dbg(&dev->dev, "flushing now\n");
242
243 mutex_lock(&ff->mutex);
244
245 for (i = 0; i < ff->max_effects; i++)
246 erase_effect(dev, i, file);
247
248 mutex_unlock(&ff->mutex);
249
250 return 0;
251}
252EXPORT_SYMBOL_GPL(input_ff_flush);
253
254/**
255 * input_ff_event() - generic handler for force-feedback events
256 * @dev: input device to send the effect to
257 * @type: event type (anything but EV_FF is ignored)
258 * @code: event code
259 * @value: event value
260 */
261int input_ff_event(struct input_dev *dev, unsigned int type,
262 unsigned int code, int value)
263{
264 struct ff_device *ff = dev->ff;
265
266 if (type != EV_FF)
267 return 0;
268
269 switch (code) {
270 case FF_GAIN:
271 if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
272 break;
273
274 ff->set_gain(dev, value);
275 break;
276
277 case FF_AUTOCENTER:
278 if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
279 break;
280
281 ff->set_autocenter(dev, value);
282 break;
283
284 default:
285 if (check_effect_access(ff, code, NULL) == 0)
286 ff->playback(dev, code, value);
287 break;
288 }
289
290 return 0;
291}
292EXPORT_SYMBOL_GPL(input_ff_event);
293
294/**
295 * input_ff_create() - create force-feedback device
296 * @dev: input device supporting force-feedback
297 * @max_effects: maximum number of effects supported by the device
298 *
299 * This function allocates all necessary memory for a force feedback
300 * portion of an input device and installs all default handlers.
301 * @dev->ffbit should be already set up before calling this function.
302 * Once ff device is created you need to setup its upload, erase,
303 * playback and other handlers before registering input device
304 */
305int input_ff_create(struct input_dev *dev, unsigned int max_effects)
306{
307 struct ff_device *ff;
308 size_t ff_dev_size;
309 int i;
310
311 if (!max_effects) {
312 dev_err(&dev->dev, "cannot allocate device without any effects\n");
313 return -EINVAL;
314 }
315
316 if (max_effects > FF_MAX_EFFECTS) {
317 dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
318 return -EINVAL;
319 }
320
321 ff_dev_size = sizeof(struct ff_device) +
322 max_effects * sizeof(struct file *);
323 if (ff_dev_size < max_effects) /* overflow */
324 return -EINVAL;
325
326 ff = kzalloc(ff_dev_size, GFP_KERNEL);
327 if (!ff)
328 return -ENOMEM;
329
330 ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
331 GFP_KERNEL);
332 if (!ff->effects) {
333 kfree(ff);
334 return -ENOMEM;
335 }
336
337 ff->max_effects = max_effects;
338 mutex_init(&ff->mutex);
339
340 dev->ff = ff;
341 dev->flush = input_ff_flush;
342 dev->event = input_ff_event;
343 __set_bit(EV_FF, dev->evbit);
344
345 /* Copy "true" bits into ff device bitmap */
346 for_each_set_bit(i, dev->ffbit, FF_CNT)
347 __set_bit(i, ff->ffbit);
348
349 /* we can emulate RUMBLE with periodic effects */
350 if (test_bit(FF_PERIODIC, ff->ffbit))
351 __set_bit(FF_RUMBLE, dev->ffbit);
352
353 return 0;
354}
355EXPORT_SYMBOL_GPL(input_ff_create);
356
357/**
358 * input_ff_destroy() - frees force feedback portion of input device
359 * @dev: input device supporting force feedback
360 *
361 * This function is only needed in error path as input core will
362 * automatically free force feedback structures when device is
363 * destroyed.
364 */
365void input_ff_destroy(struct input_dev *dev)
366{
367 struct ff_device *ff = dev->ff;
368
369 __clear_bit(EV_FF, dev->evbit);
370 if (ff) {
371 if (ff->destroy)
372 ff->destroy(ff);
373 kfree(ff->private);
374 kfree(ff->effects);
375 kfree(ff);
376 dev->ff = NULL;
377 }
378}
379EXPORT_SYMBOL_GPL(input_ff_destroy);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Force feedback support for Linux input subsystem
4 *
5 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
6 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
7 */
8
9/* #define DEBUG */
10
11#include <linux/input.h>
12#include <linux/limits.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/overflow.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18
19/*
20 * Check that the effect_id is a valid effect and whether the user
21 * is the owner
22 */
23static int check_effect_access(struct ff_device *ff, int effect_id,
24 struct file *file)
25{
26 if (effect_id < 0 || effect_id >= ff->max_effects ||
27 !ff->effect_owners[effect_id])
28 return -EINVAL;
29
30 if (file && ff->effect_owners[effect_id] != file)
31 return -EACCES;
32
33 return 0;
34}
35
36/*
37 * Checks whether 2 effects can be combined together
38 */
39static inline int check_effects_compatible(struct ff_effect *e1,
40 struct ff_effect *e2)
41{
42 return e1->type == e2->type &&
43 (e1->type != FF_PERIODIC ||
44 e1->u.periodic.waveform == e2->u.periodic.waveform);
45}
46
47/*
48 * Convert an effect into compatible one
49 */
50static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
51{
52 int magnitude;
53
54 switch (effect->type) {
55 case FF_RUMBLE:
56 if (!test_bit(FF_PERIODIC, ff->ffbit))
57 return -EINVAL;
58
59 /*
60 * calculate magnitude of sine wave as average of rumble's
61 * 2/3 of strong magnitude and 1/3 of weak magnitude
62 */
63 magnitude = effect->u.rumble.strong_magnitude / 3 +
64 effect->u.rumble.weak_magnitude / 6;
65
66 effect->type = FF_PERIODIC;
67 effect->u.periodic.waveform = FF_SINE;
68 effect->u.periodic.period = 50;
69 effect->u.periodic.magnitude = magnitude;
70 effect->u.periodic.offset = 0;
71 effect->u.periodic.phase = 0;
72 effect->u.periodic.envelope.attack_length = 0;
73 effect->u.periodic.envelope.attack_level = 0;
74 effect->u.periodic.envelope.fade_length = 0;
75 effect->u.periodic.envelope.fade_level = 0;
76
77 return 0;
78
79 default:
80 /* Let driver handle conversion */
81 return 0;
82 }
83}
84
85/**
86 * input_ff_upload() - upload effect into force-feedback device
87 * @dev: input device
88 * @effect: effect to be uploaded
89 * @file: owner of the effect
90 */
91int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
92 struct file *file)
93{
94 struct ff_device *ff = dev->ff;
95 struct ff_effect *old;
96 int ret = 0;
97 int id;
98
99 if (!test_bit(EV_FF, dev->evbit))
100 return -ENOSYS;
101
102 if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
103 !test_bit(effect->type, dev->ffbit)) {
104 dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
105 return -EINVAL;
106 }
107
108 if (effect->type == FF_PERIODIC &&
109 (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
110 effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
111 !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
112 dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
113 return -EINVAL;
114 }
115
116 if (!test_bit(effect->type, ff->ffbit)) {
117 ret = compat_effect(ff, effect);
118 if (ret)
119 return ret;
120 }
121
122 mutex_lock(&ff->mutex);
123
124 if (effect->id == -1) {
125 for (id = 0; id < ff->max_effects; id++)
126 if (!ff->effect_owners[id])
127 break;
128
129 if (id >= ff->max_effects) {
130 ret = -ENOSPC;
131 goto out;
132 }
133
134 effect->id = id;
135 old = NULL;
136
137 } else {
138 id = effect->id;
139
140 ret = check_effect_access(ff, id, file);
141 if (ret)
142 goto out;
143
144 old = &ff->effects[id];
145
146 if (!check_effects_compatible(effect, old)) {
147 ret = -EINVAL;
148 goto out;
149 }
150 }
151
152 ret = ff->upload(dev, effect, old);
153 if (ret)
154 goto out;
155
156 spin_lock_irq(&dev->event_lock);
157 ff->effects[id] = *effect;
158 ff->effect_owners[id] = file;
159 spin_unlock_irq(&dev->event_lock);
160
161 out:
162 mutex_unlock(&ff->mutex);
163 return ret;
164}
165EXPORT_SYMBOL_GPL(input_ff_upload);
166
167/*
168 * Erases the effect if the requester is also the effect owner. The mutex
169 * should already be locked before calling this function.
170 */
171static int erase_effect(struct input_dev *dev, int effect_id,
172 struct file *file)
173{
174 struct ff_device *ff = dev->ff;
175 int error;
176
177 error = check_effect_access(ff, effect_id, file);
178 if (error)
179 return error;
180
181 spin_lock_irq(&dev->event_lock);
182 ff->playback(dev, effect_id, 0);
183 ff->effect_owners[effect_id] = NULL;
184 spin_unlock_irq(&dev->event_lock);
185
186 if (ff->erase) {
187 error = ff->erase(dev, effect_id);
188 if (error) {
189 spin_lock_irq(&dev->event_lock);
190 ff->effect_owners[effect_id] = file;
191 spin_unlock_irq(&dev->event_lock);
192
193 return error;
194 }
195 }
196
197 return 0;
198}
199
200/**
201 * input_ff_erase - erase a force-feedback effect from device
202 * @dev: input device to erase effect from
203 * @effect_id: id of the effect to be erased
204 * @file: purported owner of the request
205 *
206 * This function erases a force-feedback effect from specified device.
207 * The effect will only be erased if it was uploaded through the same
208 * file handle that is requesting erase.
209 */
210int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
211{
212 struct ff_device *ff = dev->ff;
213 int ret;
214
215 if (!test_bit(EV_FF, dev->evbit))
216 return -ENOSYS;
217
218 mutex_lock(&ff->mutex);
219 ret = erase_effect(dev, effect_id, file);
220 mutex_unlock(&ff->mutex);
221
222 return ret;
223}
224EXPORT_SYMBOL_GPL(input_ff_erase);
225
226/*
227 * input_ff_flush - erase all effects owned by a file handle
228 * @dev: input device to erase effect from
229 * @file: purported owner of the effects
230 *
231 * This function erases all force-feedback effects associated with
232 * the given owner from specified device. Note that @file may be %NULL,
233 * in which case all effects will be erased.
234 */
235int input_ff_flush(struct input_dev *dev, struct file *file)
236{
237 struct ff_device *ff = dev->ff;
238 int i;
239
240 dev_dbg(&dev->dev, "flushing now\n");
241
242 mutex_lock(&ff->mutex);
243
244 for (i = 0; i < ff->max_effects; i++)
245 erase_effect(dev, i, file);
246
247 mutex_unlock(&ff->mutex);
248
249 return 0;
250}
251EXPORT_SYMBOL_GPL(input_ff_flush);
252
253/**
254 * input_ff_event() - generic handler for force-feedback events
255 * @dev: input device to send the effect to
256 * @type: event type (anything but EV_FF is ignored)
257 * @code: event code
258 * @value: event value
259 */
260int input_ff_event(struct input_dev *dev, unsigned int type,
261 unsigned int code, int value)
262{
263 struct ff_device *ff = dev->ff;
264
265 if (type != EV_FF)
266 return 0;
267
268 switch (code) {
269 case FF_GAIN:
270 if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
271 break;
272
273 ff->set_gain(dev, value);
274 break;
275
276 case FF_AUTOCENTER:
277 if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
278 break;
279
280 ff->set_autocenter(dev, value);
281 break;
282
283 default:
284 if (check_effect_access(ff, code, NULL) == 0)
285 ff->playback(dev, code, value);
286 break;
287 }
288
289 return 0;
290}
291EXPORT_SYMBOL_GPL(input_ff_event);
292
293/**
294 * input_ff_create() - create force-feedback device
295 * @dev: input device supporting force-feedback
296 * @max_effects: maximum number of effects supported by the device
297 *
298 * This function allocates all necessary memory for a force feedback
299 * portion of an input device and installs all default handlers.
300 * @dev->ffbit should be already set up before calling this function.
301 * Once ff device is created you need to setup its upload, erase,
302 * playback and other handlers before registering input device
303 */
304int input_ff_create(struct input_dev *dev, unsigned int max_effects)
305{
306 struct ff_device *ff;
307 size_t ff_dev_size;
308 int i;
309
310 if (!max_effects) {
311 dev_err(&dev->dev, "cannot allocate device without any effects\n");
312 return -EINVAL;
313 }
314
315 if (max_effects > FF_MAX_EFFECTS) {
316 dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
317 return -EINVAL;
318 }
319
320 ff_dev_size = struct_size(ff, effect_owners, max_effects);
321 if (ff_dev_size == SIZE_MAX) /* overflow */
322 return -EINVAL;
323
324 ff = kzalloc(ff_dev_size, GFP_KERNEL);
325 if (!ff)
326 return -ENOMEM;
327
328 ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
329 GFP_KERNEL);
330 if (!ff->effects) {
331 kfree(ff);
332 return -ENOMEM;
333 }
334
335 ff->max_effects = max_effects;
336 mutex_init(&ff->mutex);
337
338 dev->ff = ff;
339 dev->flush = input_ff_flush;
340 dev->event = input_ff_event;
341 __set_bit(EV_FF, dev->evbit);
342
343 /* Copy "true" bits into ff device bitmap */
344 for_each_set_bit(i, dev->ffbit, FF_CNT)
345 __set_bit(i, ff->ffbit);
346
347 /* we can emulate RUMBLE with periodic effects */
348 if (test_bit(FF_PERIODIC, ff->ffbit))
349 __set_bit(FF_RUMBLE, dev->ffbit);
350
351 return 0;
352}
353EXPORT_SYMBOL_GPL(input_ff_create);
354
355/**
356 * input_ff_destroy() - frees force feedback portion of input device
357 * @dev: input device supporting force feedback
358 *
359 * This function is only needed in error path as input core will
360 * automatically free force feedback structures when device is
361 * destroyed.
362 */
363void input_ff_destroy(struct input_dev *dev)
364{
365 struct ff_device *ff = dev->ff;
366
367 __clear_bit(EV_FF, dev->evbit);
368 if (ff) {
369 if (ff->destroy)
370 ff->destroy(ff);
371 kfree(ff->private);
372 kfree(ff->effects);
373 kfree(ff);
374 dev->ff = NULL;
375 }
376}
377EXPORT_SYMBOL_GPL(input_ff_destroy);