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 : /*
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 : */
24 0 : static int check_effect_access(struct ff_device *ff, int effect_id,
25 : struct file *file)
26 : {
27 0 : if (effect_id < 0 || effect_id >= ff->max_effects ||
28 0 : !ff->effect_owners[effect_id])
29 : return -EINVAL;
30 :
31 0 : if (file && ff->effect_owners[effect_id] != file)
32 0 : return -EACCES;
33 :
34 : return 0;
35 : }
36 :
37 : /*
38 : * Checks whether 2 effects can be combined together
39 : */
40 0 : static inline int check_effects_compatible(struct ff_effect *e1,
41 : struct ff_effect *e2)
42 : {
43 0 : return e1->type == e2->type &&
44 0 : (e1->type != FF_PERIODIC ||
45 0 : e1->u.periodic.waveform == e2->u.periodic.waveform);
46 : }
47 :
48 : /*
49 : * Convert an effect into compatible one
50 : */
51 0 : static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
52 : {
53 0 : int magnitude;
54 :
55 0 : switch (effect->type) {
56 0 : case FF_RUMBLE:
57 0 : 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 0 : magnitude = effect->u.rumble.strong_magnitude / 3 +
65 0 : effect->u.rumble.weak_magnitude / 6;
66 :
67 0 : effect->type = FF_PERIODIC;
68 0 : effect->u.periodic.waveform = FF_SINE;
69 0 : effect->u.periodic.period = 50;
70 0 : effect->u.periodic.magnitude = max(magnitude, 0x7fff);
71 0 : effect->u.periodic.offset = 0;
72 0 : effect->u.periodic.phase = 0;
73 0 : effect->u.periodic.envelope.attack_length = 0;
74 0 : effect->u.periodic.envelope.attack_level = 0;
75 0 : effect->u.periodic.envelope.fade_length = 0;
76 0 : effect->u.periodic.envelope.fade_level = 0;
77 :
78 0 : 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 : */
92 0 : int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
93 : struct file *file)
94 : {
95 0 : struct ff_device *ff = dev->ff;
96 0 : struct ff_effect *old;
97 0 : int ret = 0;
98 0 : int id;
99 :
100 0 : if (!test_bit(EV_FF, dev->evbit))
101 : return -ENOSYS;
102 :
103 0 : if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
104 0 : !test_bit(effect->type, dev->ffbit)) {
105 0 : dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
106 0 : return -EINVAL;
107 : }
108 :
109 0 : if (effect->type == FF_PERIODIC &&
110 0 : (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
111 0 : effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
112 0 : !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
113 0 : dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
114 0 : return -EINVAL;
115 : }
116 :
117 0 : if (!test_bit(effect->type, ff->ffbit)) {
118 0 : ret = compat_effect(ff, effect);
119 0 : if (ret)
120 : return ret;
121 : }
122 :
123 0 : mutex_lock(&ff->mutex);
124 :
125 0 : if (effect->id == -1) {
126 0 : for (id = 0; id < ff->max_effects; id++)
127 0 : if (!ff->effect_owners[id])
128 : break;
129 :
130 0 : if (id >= ff->max_effects) {
131 0 : ret = -ENOSPC;
132 0 : goto out;
133 : }
134 :
135 0 : effect->id = id;
136 0 : old = NULL;
137 :
138 : } else {
139 0 : id = effect->id;
140 :
141 0 : ret = check_effect_access(ff, id, file);
142 0 : if (ret)
143 0 : goto out;
144 :
145 0 : old = &ff->effects[id];
146 :
147 0 : if (!check_effects_compatible(effect, old)) {
148 0 : ret = -EINVAL;
149 0 : goto out;
150 : }
151 : }
152 :
153 0 : ret = ff->upload(dev, effect, old);
154 0 : if (ret)
155 0 : goto out;
156 :
157 0 : spin_lock_irq(&dev->event_lock);
158 0 : ff->effects[id] = *effect;
159 0 : ff->effect_owners[id] = file;
160 0 : spin_unlock_irq(&dev->event_lock);
161 :
162 0 : out:
163 0 : mutex_unlock(&ff->mutex);
164 0 : return ret;
165 : }
166 : EXPORT_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 : */
172 0 : static int erase_effect(struct input_dev *dev, int effect_id,
173 : struct file *file)
174 : {
175 0 : struct ff_device *ff = dev->ff;
176 0 : int error;
177 :
178 0 : error = check_effect_access(ff, effect_id, file);
179 0 : if (error)
180 : return error;
181 :
182 0 : spin_lock_irq(&dev->event_lock);
183 0 : ff->playback(dev, effect_id, 0);
184 0 : ff->effect_owners[effect_id] = NULL;
185 0 : spin_unlock_irq(&dev->event_lock);
186 :
187 0 : if (ff->erase) {
188 0 : error = ff->erase(dev, effect_id);
189 0 : if (error) {
190 0 : spin_lock_irq(&dev->event_lock);
191 0 : ff->effect_owners[effect_id] = file;
192 0 : spin_unlock_irq(&dev->event_lock);
193 :
194 0 : 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 : */
211 0 : int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
212 : {
213 0 : struct ff_device *ff = dev->ff;
214 0 : int ret;
215 :
216 0 : if (!test_bit(EV_FF, dev->evbit))
217 : return -ENOSYS;
218 :
219 0 : mutex_lock(&ff->mutex);
220 0 : ret = erase_effect(dev, effect_id, file);
221 0 : mutex_unlock(&ff->mutex);
222 :
223 0 : return ret;
224 : }
225 : EXPORT_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 : */
236 0 : int input_ff_flush(struct input_dev *dev, struct file *file)
237 : {
238 0 : struct ff_device *ff = dev->ff;
239 0 : int i;
240 :
241 0 : dev_dbg(&dev->dev, "flushing now\n");
242 :
243 0 : mutex_lock(&ff->mutex);
244 :
245 0 : for (i = 0; i < ff->max_effects; i++)
246 0 : erase_effect(dev, i, file);
247 :
248 0 : mutex_unlock(&ff->mutex);
249 :
250 0 : return 0;
251 : }
252 : EXPORT_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 : */
261 0 : int input_ff_event(struct input_dev *dev, unsigned int type,
262 : unsigned int code, int value)
263 : {
264 0 : struct ff_device *ff = dev->ff;
265 :
266 0 : if (type != EV_FF)
267 : return 0;
268 :
269 0 : switch (code) {
270 0 : case FF_GAIN:
271 0 : if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
272 : break;
273 :
274 0 : ff->set_gain(dev, value);
275 0 : break;
276 :
277 0 : case FF_AUTOCENTER:
278 0 : if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
279 : break;
280 :
281 0 : ff->set_autocenter(dev, value);
282 0 : break;
283 :
284 0 : default:
285 0 : if (check_effect_access(ff, code, NULL) == 0)
286 0 : ff->playback(dev, code, value);
287 : break;
288 : }
289 :
290 0 : return 0;
291 : }
292 : EXPORT_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 : */
305 0 : int input_ff_create(struct input_dev *dev, unsigned int max_effects)
306 : {
307 0 : struct ff_device *ff;
308 0 : size_t ff_dev_size;
309 0 : int i;
310 :
311 0 : if (!max_effects) {
312 0 : dev_err(&dev->dev, "cannot allocate device without any effects\n");
313 0 : return -EINVAL;
314 : }
315 :
316 0 : if (max_effects > FF_MAX_EFFECTS) {
317 0 : dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
318 0 : return -EINVAL;
319 : }
320 :
321 0 : ff_dev_size = sizeof(struct ff_device) +
322 : max_effects * sizeof(struct file *);
323 0 : if (ff_dev_size < max_effects) /* overflow */
324 : return -EINVAL;
325 :
326 0 : ff = kzalloc(ff_dev_size, GFP_KERNEL);
327 0 : if (!ff)
328 : return -ENOMEM;
329 :
330 0 : ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
331 : GFP_KERNEL);
332 0 : if (!ff->effects) {
333 0 : kfree(ff);
334 0 : return -ENOMEM;
335 : }
336 :
337 0 : ff->max_effects = max_effects;
338 0 : mutex_init(&ff->mutex);
339 :
340 0 : dev->ff = ff;
341 0 : dev->flush = input_ff_flush;
342 0 : dev->event = input_ff_event;
343 0 : __set_bit(EV_FF, dev->evbit);
344 :
345 : /* Copy "true" bits into ff device bitmap */
346 0 : for_each_set_bit(i, dev->ffbit, FF_CNT)
347 0 : __set_bit(i, ff->ffbit);
348 :
349 : /* we can emulate RUMBLE with periodic effects */
350 0 : if (test_bit(FF_PERIODIC, ff->ffbit))
351 0 : __set_bit(FF_RUMBLE, dev->ffbit);
352 :
353 : return 0;
354 : }
355 : EXPORT_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 : */
365 0 : void input_ff_destroy(struct input_dev *dev)
366 : {
367 0 : struct ff_device *ff = dev->ff;
368 :
369 0 : __clear_bit(EV_FF, dev->evbit);
370 0 : if (ff) {
371 0 : if (ff->destroy)
372 0 : ff->destroy(ff);
373 0 : kfree(ff->private);
374 0 : kfree(ff->effects);
375 0 : kfree(ff);
376 0 : dev->ff = NULL;
377 : }
378 0 : }
379 : EXPORT_SYMBOL_GPL(input_ff_destroy);
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