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