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Anssi Hannula509ca1a2006-07-19 01:40:22 -04001/*
2 * Force feedback support for Linux input subsystem
3 *
4 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
5 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
6 */
7
8/*
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 */
23
24/* #define DEBUG */
25
26#define debug(format, arg...) pr_debug("ff-core: " format "\n", ## arg)
27
28#include <linux/input.h>
29#include <linux/module.h>
30#include <linux/mutex.h>
31
32/*
33 * Check that the effect_id is a valid effect and whether the user
34 * is the owner
35 */
36static int check_effect_access(struct ff_device *ff, int effect_id,
37 struct file *file)
38{
39 if (effect_id < 0 || effect_id >= ff->max_effects ||
40 !ff->effect_owners[effect_id])
41 return -EINVAL;
42
43 if (file && ff->effect_owners[effect_id] != file)
44 return -EACCES;
45
46 return 0;
47}
48
49/*
50 * Checks whether 2 effects can be combined together
51 */
52static inline int check_effects_compatible(struct ff_effect *e1,
53 struct ff_effect *e2)
54{
55 return e1->type == e2->type &&
56 (e1->type != FF_PERIODIC ||
57 e1->u.periodic.waveform == e2->u.periodic.waveform);
58}
59
60/*
61 * Convert an effect into compatible one
62 */
63static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
64{
65 int magnitude;
66
67 switch (effect->type) {
68 case FF_RUMBLE:
69 if (!test_bit(FF_PERIODIC, ff->ffbit))
70 return -EINVAL;
71
72 /*
73 * calculate manginude of sine wave as average of rumble's
74 * 2/3 of strong magnitude and 1/3 of weak magnitude
75 */
76 magnitude = effect->u.rumble.strong_magnitude / 3 +
77 effect->u.rumble.weak_magnitude / 6;
78
79 effect->type = FF_PERIODIC;
80 effect->u.periodic.waveform = FF_SINE;
81 effect->u.periodic.period = 50;
82 effect->u.periodic.magnitude = max(magnitude, 0x7fff);
83 effect->u.periodic.offset = 0;
84 effect->u.periodic.phase = 0;
85 effect->u.periodic.envelope.attack_length = 0;
86 effect->u.periodic.envelope.attack_level = 0;
87 effect->u.periodic.envelope.fade_length = 0;
88 effect->u.periodic.envelope.fade_level = 0;
89
90 return 0;
91
92 default:
93 /* Let driver handle conversion */
94 return 0;
95 }
96}
97
98/**
99 * input_ff_upload() - upload effect into force-feedback device
100 * @dev: input device
101 * @effect: effect to be uploaded
102 * @file: owner of the effect
103 */
104int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
105 struct file *file)
106{
107 struct ff_device *ff = dev->ff;
108 struct ff_effect *old;
109 int ret = 0;
110 int id;
111
112 if (!test_bit(EV_FF, dev->evbit))
113 return -ENOSYS;
114
115 if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
116 !test_bit(effect->type, dev->ffbit)) {
117 debug("invalid or not supported effect type in upload");
118 return -EINVAL;
119 }
120
121 if (effect->type == FF_PERIODIC &&
122 (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
123 effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
124 !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
125 debug("invalid or not supported wave form in upload");
126 return -EINVAL;
127 }
128
129 if (!test_bit(effect->type, ff->ffbit)) {
130 ret = compat_effect(ff, effect);
131 if (ret)
132 return ret;
133 }
134
135 mutex_lock(&ff->mutex);
136
137 if (effect->id == -1) {
138 for (id = 0; id < ff->max_effects; id++)
139 if (!ff->effect_owners[id])
140 break;
141
142 if (id >= ff->max_effects) {
143 ret = -ENOSPC;
144 goto out;
145 }
146
147 effect->id = id;
148 old = NULL;
149
150 } else {
151 id = effect->id;
152
153 ret = check_effect_access(ff, id, file);
154 if (ret)
155 goto out;
156
157 old = &ff->effects[id];
158
159 if (!check_effects_compatible(effect, old)) {
160 ret = -EINVAL;
161 goto out;
162 }
163 }
164
165 ret = ff->upload(dev, effect, old);
166 if (ret)
167 goto out;
168
169 ff->effects[id] = *effect;
170 ff->effect_owners[id] = file;
171
172 out:
173 mutex_unlock(&ff->mutex);
174 return ret;
175}
176EXPORT_SYMBOL_GPL(input_ff_upload);
177
178/*
179 * Erases the effect if the requester is also the effect owner. The mutex
180 * should already be locked before calling this function.
181 */
182static int erase_effect(struct input_dev *dev, int effect_id,
183 struct file *file)
184{
185 struct ff_device *ff = dev->ff;
186 int error;
187
188 error = check_effect_access(ff, effect_id, file);
189 if (error)
190 return error;
191
192 ff->playback(dev, effect_id, 0);
193
194 if (ff->erase) {
195 error = ff->erase(dev, effect_id);
196 if (error)
197 return error;
198 }
199
200 ff->effect_owners[effect_id] = NULL;
201
202 return 0;
203}
204
205/**
Randy Dunlape4477d22006-11-24 00:43:09 -0500206 * input_ff_erase - erase a force-feedback effect from device
Anssi Hannula509ca1a2006-07-19 01:40:22 -0400207 * @dev: input device to erase effect from
208 * @effect_id: id of the ffect to be erased
209 * @file: purported owner of the request
210 *
211 * This function erases a force-feedback effect from specified device.
212 * The effect will only be erased if it was uploaded through the same
213 * file handle that is requesting erase.
214 */
215int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
216{
217 struct ff_device *ff = dev->ff;
218 int ret;
219
220 if (!test_bit(EV_FF, dev->evbit))
221 return -ENOSYS;
222
223 mutex_lock(&ff->mutex);
224 ret = erase_effect(dev, effect_id, file);
225 mutex_unlock(&ff->mutex);
226
227 return ret;
228}
229EXPORT_SYMBOL_GPL(input_ff_erase);
230
231/*
232 * flush_effects - erase all effects owned by a file handle
233 */
234static int flush_effects(struct input_dev *dev, struct file *file)
235{
236 struct ff_device *ff = dev->ff;
237 int i;
238
239 debug("flushing now");
240
241 mutex_lock(&ff->mutex);
242
243 for (i = 0; i < ff->max_effects; i++)
244 erase_effect(dev, i, file);
245
246 mutex_unlock(&ff->mutex);
247
248 return 0;
249}
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 mutex_lock(&ff->mutex);
267
268 switch (code) {
269 case FF_GAIN:
270 if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff)
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 > 0xffff)
278 break;
279
280 ff->set_autocenter(dev, value);
281 break;
282
283 default:
Dmitry Torokhovdec3eb02007-05-03 00:51:10 -0400284 if (check_effect_access(ff, code, NULL) == 0)
285 ff->playback(dev, code, value);
Anssi Hannula509ca1a2006-07-19 01:40:22 -0400286 break;
287 }
288
289 mutex_unlock(&ff->mutex);
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, int max_effects)
306{
307 struct ff_device *ff;
308 int i;
309
310 if (!max_effects) {
311 printk(KERN_ERR
312 "ff-core: cannot allocate device without any effects\n");
313 return -EINVAL;
314 }
315
316 ff = kzalloc(sizeof(struct ff_device) +
317 max_effects * sizeof(struct file *), GFP_KERNEL);
318 if (!ff)
319 return -ENOMEM;
320
321 ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
322 GFP_KERNEL);
323 if (!ff->effects) {
324 kfree(ff);
325 return -ENOMEM;
326 }
327
328 ff->max_effects = max_effects;
329 mutex_init(&ff->mutex);
330
331 dev->ff = ff;
332 dev->flush = flush_effects;
333 dev->event = input_ff_event;
334 set_bit(EV_FF, dev->evbit);
335
336 /* Copy "true" bits into ff device bitmap */
337 for (i = 0; i <= FF_MAX; i++)
338 if (test_bit(i, dev->ffbit))
339 set_bit(i, ff->ffbit);
340
341 /* we can emulate RUMBLE with periodic effects */
342 if (test_bit(FF_PERIODIC, ff->ffbit))
343 set_bit(FF_RUMBLE, dev->ffbit);
344
345 return 0;
346}
347EXPORT_SYMBOL_GPL(input_ff_create);
348
349/**
350 * input_ff_free() - frees force feedback portion of input device
Randy Dunlape4477d22006-11-24 00:43:09 -0500351 * @dev: input device supporting force feedback
Anssi Hannula509ca1a2006-07-19 01:40:22 -0400352 *
353 * This function is only needed in error path as input core will
354 * automatically free force feedback structures when device is
355 * destroyed.
356 */
357void input_ff_destroy(struct input_dev *dev)
358{
359 clear_bit(EV_FF, dev->evbit);
360 if (dev->ff) {
361 if (dev->ff->destroy)
362 dev->ff->destroy(dev->ff);
363 kfree(dev->ff->private);
364 kfree(dev->ff);
365 dev->ff = NULL;
366 }
367}
368EXPORT_SYMBOL_GPL(input_ff_destroy);