Line data Source code
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 : */
21 : static int check_effect_access(struct ff_device *ff, int effect_id,
22 : struct file *file)
23 : {
24 0 : if (effect_id < 0 || effect_id >= ff->max_effects ||
25 0 : !ff->effect_owners[effect_id])
26 : return -EINVAL;
27 :
28 0 : 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 : */
37 : static inline int check_effects_compatible(struct ff_effect *e1,
38 : struct ff_effect *e2)
39 : {
40 0 : return e1->type == e2->type &&
41 0 : (e1->type != FF_PERIODIC ||
42 0 : e1->u.periodic.waveform == e2->u.periodic.waveform);
43 : }
44 :
45 : /*
46 : * Convert an effect into compatible one
47 : */
48 0 : static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
49 : {
50 : int magnitude;
51 :
52 0 : switch (effect->type) {
53 : case FF_RUMBLE:
54 0 : 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 0 : magnitude = effect->u.rumble.strong_magnitude / 3 +
62 0 : effect->u.rumble.weak_magnitude / 6;
63 :
64 0 : effect->type = FF_PERIODIC;
65 0 : effect->u.periodic.waveform = FF_SINE;
66 0 : effect->u.periodic.period = 50;
67 0 : effect->u.periodic.magnitude = magnitude;
68 0 : effect->u.periodic.offset = 0;
69 0 : effect->u.periodic.phase = 0;
70 0 : effect->u.periodic.envelope.attack_length = 0;
71 0 : effect->u.periodic.envelope.attack_level = 0;
72 0 : effect->u.periodic.envelope.fade_length = 0;
73 0 : effect->u.periodic.envelope.fade_level = 0;
74 :
75 0 : 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 : */
89 0 : int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
90 : struct file *file)
91 : {
92 0 : struct ff_device *ff = dev->ff;
93 : struct ff_effect *old;
94 0 : int ret = 0;
95 : int id;
96 :
97 0 : if (!test_bit(EV_FF, dev->evbit))
98 : return -ENOSYS;
99 :
100 0 : if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
101 0 : !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 0 : if (effect->type == FF_PERIODIC &&
107 0 : (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
108 0 : effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
109 0 : !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 0 : if (!test_bit(effect->type, ff->ffbit)) {
115 0 : ret = compat_effect(ff, effect);
116 0 : if (ret)
117 : return ret;
118 : }
119 :
120 0 : mutex_lock(&ff->mutex);
121 :
122 0 : if (effect->id == -1) {
123 0 : for (id = 0; id < ff->max_effects; id++)
124 0 : if (!ff->effect_owners[id])
125 : break;
126 :
127 0 : if (id >= ff->max_effects) {
128 : ret = -ENOSPC;
129 : goto out;
130 : }
131 :
132 0 : effect->id = id;
133 0 : old = NULL;
134 :
135 : } else {
136 0 : id = effect->id;
137 :
138 0 : ret = check_effect_access(ff, id, file);
139 0 : if (ret)
140 : goto out;
141 :
142 0 : old = &ff->effects[id];
143 :
144 0 : if (!check_effects_compatible(effect, old)) {
145 : ret = -EINVAL;
146 : goto out;
147 : }
148 : }
149 :
150 0 : ret = ff->upload(dev, effect, old);
151 0 : if (ret)
152 : goto out;
153 :
154 0 : spin_lock_irq(&dev->event_lock);
155 0 : ff->effects[id] = *effect;
156 0 : ff->effect_owners[id] = file;
157 0 : spin_unlock_irq(&dev->event_lock);
158 :
159 : out:
160 0 : mutex_unlock(&ff->mutex);
161 0 : return ret;
162 : }
163 : EXPORT_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 : */
169 0 : static int erase_effect(struct input_dev *dev, int effect_id,
170 : struct file *file)
171 : {
172 0 : struct ff_device *ff = dev->ff;
173 : int error;
174 :
175 0 : error = check_effect_access(ff, effect_id, file);
176 0 : if (error)
177 : return error;
178 :
179 0 : spin_lock_irq(&dev->event_lock);
180 0 : ff->playback(dev, effect_id, 0);
181 0 : ff->effect_owners[effect_id] = NULL;
182 0 : spin_unlock_irq(&dev->event_lock);
183 :
184 0 : if (ff->erase) {
185 0 : error = ff->erase(dev, effect_id);
186 0 : if (error) {
187 0 : spin_lock_irq(&dev->event_lock);
188 0 : ff->effect_owners[effect_id] = file;
189 0 : spin_unlock_irq(&dev->event_lock);
190 :
191 0 : 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 : */
208 0 : int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
209 : {
210 0 : struct ff_device *ff = dev->ff;
211 : int ret;
212 :
213 0 : if (!test_bit(EV_FF, dev->evbit))
214 : return -ENOSYS;
215 :
216 0 : mutex_lock(&ff->mutex);
217 0 : ret = erase_effect(dev, effect_id, file);
218 0 : mutex_unlock(&ff->mutex);
219 :
220 0 : return ret;
221 : }
222 : EXPORT_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 : */
233 0 : int input_ff_flush(struct input_dev *dev, struct file *file)
234 : {
235 0 : struct ff_device *ff = dev->ff;
236 : int i;
237 :
238 : dev_dbg(&dev->dev, "flushing now\n");
239 :
240 0 : mutex_lock(&ff->mutex);
241 :
242 0 : for (i = 0; i < ff->max_effects; i++)
243 0 : erase_effect(dev, i, file);
244 :
245 0 : mutex_unlock(&ff->mutex);
246 :
247 0 : return 0;
248 : }
249 : EXPORT_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 : */
258 0 : int input_ff_event(struct input_dev *dev, unsigned int type,
259 : unsigned int code, int value)
260 : {
261 0 : struct ff_device *ff = dev->ff;
262 :
263 0 : if (type != EV_FF)
264 : return 0;
265 :
266 0 : switch (code) {
267 : case FF_GAIN:
268 0 : if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
269 : break;
270 :
271 0 : ff->set_gain(dev, value);
272 0 : break;
273 :
274 : case FF_AUTOCENTER:
275 0 : if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
276 : break;
277 :
278 0 : ff->set_autocenter(dev, value);
279 0 : break;
280 :
281 : default:
282 0 : if (check_effect_access(ff, code, NULL) == 0)
283 0 : ff->playback(dev, code, value);
284 : break;
285 : }
286 :
287 : return 0;
288 : }
289 : EXPORT_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 : */
302 0 : int 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 0 : if (!max_effects) {
309 0 : dev_err(&dev->dev, "cannot allocate device without any effects\n");
310 0 : return -EINVAL;
311 : }
312 :
313 0 : if (max_effects > FF_MAX_EFFECTS) {
314 0 : dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
315 0 : return -EINVAL;
316 : }
317 :
318 0 : ff_dev_size = sizeof(struct ff_device) +
319 : max_effects * sizeof(struct file *);
320 0 : if (ff_dev_size < max_effects) /* overflow */
321 : return -EINVAL;
322 :
323 0 : ff = kzalloc(ff_dev_size, GFP_KERNEL);
324 0 : if (!ff)
325 : return -ENOMEM;
326 :
327 0 : ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
328 : GFP_KERNEL);
329 0 : if (!ff->effects) {
330 0 : kfree(ff);
331 0 : return -ENOMEM;
332 : }
333 :
334 0 : ff->max_effects = max_effects;
335 0 : mutex_init(&ff->mutex);
336 :
337 0 : dev->ff = ff;
338 0 : dev->flush = input_ff_flush;
339 0 : dev->event = input_ff_event;
340 0 : __set_bit(EV_FF, dev->evbit);
341 :
342 : /* Copy "true" bits into ff device bitmap */
343 0 : for_each_set_bit(i, dev->ffbit, FF_CNT)
344 0 : __set_bit(i, ff->ffbit);
345 :
346 : /* we can emulate RUMBLE with periodic effects */
347 0 : if (test_bit(FF_PERIODIC, ff->ffbit))
348 0 : __set_bit(FF_RUMBLE, dev->ffbit);
349 :
350 : return 0;
351 : }
352 : EXPORT_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 : */
362 0 : void input_ff_destroy(struct input_dev *dev)
363 : {
364 0 : struct ff_device *ff = dev->ff;
365 :
366 0 : __clear_bit(EV_FF, dev->evbit);
367 0 : if (ff) {
368 0 : if (ff->destroy)
369 0 : ff->destroy(ff);
370 0 : kfree(ff->private);
371 0 : kfree(ff->effects);
372 0 : kfree(ff);
373 0 : dev->ff = NULL;
374 : }
375 0 : }
376 : EXPORT_SYMBOL_GPL(input_ff_destroy);
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