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Anssi Hannula7d928a22006-07-19 01:40:30 -04001/*
2 * Force feedback support for memoryless devices
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-memless: " format "\n", ## arg)
27
28#include <linux/input.h>
29#include <linux/module.h>
30#include <linux/mutex.h>
31#include <linux/spinlock.h>
32#include <linux/sched.h>
33
34#include "fixp-arith.h"
35
36MODULE_LICENSE("GPL");
37MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
38MODULE_DESCRIPTION("Force feedback support for memoryless devices");
39
40/* Number of effects handled with memoryless devices */
41#define FF_MEMLESS_EFFECTS 16
42
43/* Envelope update interval in ms */
44#define FF_ENVELOPE_INTERVAL 50
45
46#define FF_EFFECT_STARTED 0
47#define FF_EFFECT_PLAYING 1
48#define FF_EFFECT_ABORTING 2
49
50struct ml_effect_state {
51 struct ff_effect *effect;
52 unsigned long flags; /* effect state (STARTED, PLAYING, etc) */
53 int count; /* loop count of the effect */
54 unsigned long play_at; /* start time */
55 unsigned long stop_at; /* stop time */
56 unsigned long adj_at; /* last time the effect was sent */
57};
58
59struct ml_device {
60 void *private;
61 struct ml_effect_state states[FF_MEMLESS_EFFECTS];
62 int gain;
63 struct timer_list timer;
64 spinlock_t timer_lock;
65 struct input_dev *dev;
66
67 int (*play_effect)(struct input_dev *dev, void *data,
68 struct ff_effect *effect);
69};
70
71static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
72{
73 static const struct ff_envelope empty_envelope;
74
75 switch (effect->type) {
76 case FF_PERIODIC:
77 return &effect->u.periodic.envelope;
78 case FF_CONSTANT:
79 return &effect->u.constant.envelope;
80 default:
81 return &empty_envelope;
82 }
83}
84
85/*
86 * Check for the next time envelope requires an update on memoryless devices
87 */
88static unsigned long calculate_next_time(struct ml_effect_state *state)
89{
90 const struct ff_envelope *envelope = get_envelope(state->effect);
91 unsigned long attack_stop, fade_start, next_fade;
92
93 if (envelope->attack_length) {
94 attack_stop = state->play_at +
95 msecs_to_jiffies(envelope->attack_length);
96 if (time_before(state->adj_at, attack_stop))
97 return state->adj_at +
98 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
99 }
100
101 if (state->effect->replay.length) {
102 if (envelope->fade_length) {
103 /* check when fading should start */
104 fade_start = state->stop_at -
105 msecs_to_jiffies(envelope->fade_length);
106
107 if (time_before(state->adj_at, fade_start))
108 return fade_start;
109
110 /* already fading, advance to next checkpoint */
111 next_fade = state->adj_at +
112 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
113 if (time_before(next_fade, state->stop_at))
114 return next_fade;
115 }
116
117 return state->stop_at;
118 }
119
120 return state->play_at;
121}
122
123static void ml_schedule_timer(struct ml_device *ml)
124{
125 struct ml_effect_state *state;
126 unsigned long now = jiffies;
127 unsigned long earliest = 0;
128 unsigned long next_at;
129 int events = 0;
130 int i;
131
132 debug("calculating next timer");
133
134 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
135
136 state = &ml->states[i];
137
138 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
139 continue;
140
141 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
142 next_at = calculate_next_time(state);
143 else
144 next_at = state->play_at;
145
146 if (time_before_eq(now, next_at) &&
147 (++events == 1 || time_before(next_at, earliest)))
148 earliest = next_at;
149 }
150
151 if (!events) {
152 debug("no actions");
153 del_timer(&ml->timer);
154 } else {
155 debug("timer set");
156 mod_timer(&ml->timer, earliest);
157 }
158}
159
160/*
161 * Apply an envelope to a value
162 */
163static int apply_envelope(struct ml_effect_state *state, int value,
164 struct ff_envelope *envelope)
165{
166 struct ff_effect *effect = state->effect;
167 unsigned long now = jiffies;
168 int time_from_level;
169 int time_of_envelope;
170 int envelope_level;
171 int difference;
172
173 if (envelope->attack_length &&
174 time_before(now,
175 state->play_at + msecs_to_jiffies(envelope->attack_length))) {
176 debug("value = 0x%x, attack_level = 0x%x", value,
177 envelope->attack_level);
178 time_from_level = jiffies_to_msecs(now - state->play_at);
179 time_of_envelope = envelope->attack_length;
180 envelope_level = min_t(__s16, envelope->attack_level, 0x7fff);
181
182 } else if (envelope->fade_length && effect->replay.length &&
183 time_after(now,
184 state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
185 time_before(now, state->stop_at)) {
186 time_from_level = jiffies_to_msecs(state->stop_at - now);
187 time_of_envelope = envelope->fade_length;
188 envelope_level = min_t(__s16, envelope->fade_level, 0x7fff);
189 } else
190 return value;
191
192 difference = abs(value) - envelope_level;
193
194 debug("difference = %d", difference);
195 debug("time_from_level = 0x%x", time_from_level);
196 debug("time_of_envelope = 0x%x", time_of_envelope);
197
198 difference = difference * time_from_level / time_of_envelope;
199
200 debug("difference = %d", difference);
201
202 return value < 0 ?
203 -(difference + envelope_level) : (difference + envelope_level);
204}
205
206/*
207 * Return the type the effect has to be converted into (memless devices)
208 */
209static int get_compatible_type(struct ff_device *ff, int effect_type)
210{
211
212 if (test_bit(effect_type, ff->ffbit))
213 return effect_type;
214
215 if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
216 return FF_RUMBLE;
217
218 printk(KERN_ERR
219 "ff-memless: invalid type in get_compatible_type()\n");
220
221 return 0;
222}
223
224/*
225 * Combine two effects and apply gain.
226 */
227static void ml_combine_effects(struct ff_effect *effect,
228 struct ml_effect_state *state,
229 int gain)
230{
231 struct ff_effect *new = state->effect;
232 unsigned int strong, weak, i;
233 int x, y;
234 fixp_t level;
235
236 switch (new->type) {
237 case FF_CONSTANT:
238 i = new->direction * 360 / 0xffff;
239 level = fixp_new16(apply_envelope(state,
240 new->u.constant.level,
241 &new->u.constant.envelope));
242 x = fixp_mult(fixp_sin(i), level) * gain / 0xffff;
243 y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff;
244 /*
245 * here we abuse ff_ramp to hold x and y of constant force
246 * If in future any driver wants something else than x and y
247 * in s8, this should be changed to something more generic
248 */
249 effect->u.ramp.start_level =
250 max(min(effect->u.ramp.start_level + x, 0x7f), -0x80);
251 effect->u.ramp.end_level =
252 max(min(effect->u.ramp.end_level + y, 0x7f), -0x80);
253 break;
254
255 case FF_RUMBLE:
256 strong = new->u.rumble.strong_magnitude * gain / 0xffff;
257 weak = new->u.rumble.weak_magnitude * gain / 0xffff;
258 effect->u.rumble.strong_magnitude =
259 min(strong + effect->u.rumble.strong_magnitude,
260 0xffffU);
261 effect->u.rumble.weak_magnitude =
262 min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
263 break;
264
265 case FF_PERIODIC:
266 i = apply_envelope(state, abs(new->u.periodic.magnitude),
267 &new->u.periodic.envelope);
268
269 /* here we also scale it 0x7fff => 0xffff */
270 i = i * gain / 0x7fff;
271
272 effect->u.rumble.strong_magnitude =
273 min(i + effect->u.rumble.strong_magnitude, 0xffffU);
274 effect->u.rumble.weak_magnitude =
275 min(i + effect->u.rumble.weak_magnitude, 0xffffU);
276 break;
277
278 default:
279 printk(KERN_ERR "ff-memless: invalid type in ml_combine_effects()\n");
280 break;
281 }
282
283}
284
285
286/*
287 * Because memoryless devices have only one effect per effect type active
288 * at one time we have to combine multiple effects into one
289 */
290static int ml_get_combo_effect(struct ml_device *ml,
291 unsigned long *effect_handled,
292 struct ff_effect *combo_effect)
293{
294 struct ff_effect *effect;
295 struct ml_effect_state *state;
296 int effect_type;
297 int i;
298
299 memset(combo_effect, 0, sizeof(struct ff_effect));
300
301 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
302 if (__test_and_set_bit(i, effect_handled))
303 continue;
304
305 state = &ml->states[i];
306 effect = state->effect;
307
308 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
309 continue;
310
311 if (time_before(jiffies, state->play_at))
312 continue;
313
314 /*
315 * here we have started effects that are either
316 * currently playing (and may need be aborted)
317 * or need to start playing.
318 */
319 effect_type = get_compatible_type(ml->dev->ff, effect->type);
320 if (combo_effect->type != effect_type) {
321 if (combo_effect->type != 0) {
322 __clear_bit(i, effect_handled);
323 continue;
324 }
325 combo_effect->type = effect_type;
326 }
327
328 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
329 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
330 __clear_bit(FF_EFFECT_STARTED, &state->flags);
331 } else if (effect->replay.length &&
332 time_after_eq(jiffies, state->stop_at)) {
333
334 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
335
336 if (--state->count <= 0) {
337 __clear_bit(FF_EFFECT_STARTED, &state->flags);
338 } else {
339 state->play_at = jiffies +
340 msecs_to_jiffies(effect->replay.delay);
341 state->stop_at = state->play_at +
342 msecs_to_jiffies(effect->replay.length);
343 }
344 } else {
345 __set_bit(FF_EFFECT_PLAYING, &state->flags);
346 state->adj_at = jiffies;
347 ml_combine_effects(combo_effect, state, ml->gain);
348 }
349 }
350
351 return combo_effect->type != 0;
352}
353
354static void ml_play_effects(struct ml_device *ml)
355{
356 struct ff_effect effect;
357 DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
358
359 memset(handled_bm, 0, sizeof(handled_bm));
360
361 while (ml_get_combo_effect(ml, handled_bm, &effect))
362 ml->play_effect(ml->dev, ml->private, &effect);
363
364 ml_schedule_timer(ml);
365}
366
367static void ml_effect_timer(unsigned long timer_data)
368{
369 struct input_dev *dev = (struct input_dev *)timer_data;
370 struct ml_device *ml = dev->ff->private;
371
372 debug("timer: updating effects");
373
374 spin_lock(&ml->timer_lock);
375 ml_play_effects(ml);
376 spin_unlock(&ml->timer_lock);
377}
378
379static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
380{
381 struct ml_device *ml = dev->ff->private;
382 int i;
383
384 spin_lock_bh(&ml->timer_lock);
385
386 ml->gain = gain;
387
388 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
389 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
390
391 ml_play_effects(ml);
392
393 spin_unlock_bh(&ml->timer_lock);
394}
395
396static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
397{
398 struct ml_device *ml = dev->ff->private;
399 struct ml_effect_state *state = &ml->states[effect_id];
400
401 spin_lock_bh(&ml->timer_lock);
402
403 if (value > 0) {
404 debug("initiated play");
405
406 __set_bit(FF_EFFECT_STARTED, &state->flags);
407 state->count = value;
408 state->play_at = jiffies +
409 msecs_to_jiffies(state->effect->replay.delay);
410 state->stop_at = state->play_at +
411 msecs_to_jiffies(state->effect->replay.length);
412 state->adj_at = state->play_at;
413
414 ml_schedule_timer(ml);
415
416 } else {
417 debug("initiated stop");
418
419 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
420 __set_bit(FF_EFFECT_ABORTING, &state->flags);
421 else
422 __clear_bit(FF_EFFECT_STARTED, &state->flags);
423
424 ml_play_effects(ml);
425 }
426
427 spin_unlock_bh(&ml->timer_lock);
428
429 return 0;
430}
431
432static int ml_ff_upload(struct input_dev *dev,
433 struct ff_effect *effect, struct ff_effect *old)
434{
435 struct ml_device *ml = dev->ff->private;
436 struct ml_effect_state *state = &ml->states[effect->id];
437
438 spin_lock_bh(&ml->timer_lock);
439
440 if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
441 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
442 state->play_at = jiffies +
443 msecs_to_jiffies(state->effect->replay.delay);
444 state->stop_at = state->play_at +
445 msecs_to_jiffies(state->effect->replay.length);
446 state->adj_at = state->play_at;
447 ml_schedule_timer(ml);
448 }
449
450 spin_unlock_bh(&ml->timer_lock);
451
452 return 0;
453}
454
455static void ml_ff_destroy(struct ff_device *ff)
456{
457 struct ml_device *ml = ff->private;
458
459 kfree(ml->private);
460}
461
462/**
Randy Dunlape4477d22006-11-24 00:43:09 -0500463 * input_ff_create_memless() - create memoryless force-feedback device
Anssi Hannula7d928a22006-07-19 01:40:30 -0400464 * @dev: input device supporting force-feedback
465 * @data: driver-specific data to be passed into @play_effect
466 * @play_effect: driver-specific method for playing FF effect
467 */
468int input_ff_create_memless(struct input_dev *dev, void *data,
469 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
470{
471 struct ml_device *ml;
472 struct ff_device *ff;
473 int error;
474 int i;
475
476 ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
477 if (!ml)
478 return -ENOMEM;
479
480 ml->dev = dev;
481 ml->private = data;
482 ml->play_effect = play_effect;
483 ml->gain = 0xffff;
484 spin_lock_init(&ml->timer_lock);
485 setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
486
487 set_bit(FF_GAIN, dev->ffbit);
488
489 error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
490 if (error) {
491 kfree(ml);
492 return error;
493 }
494
495 ff = dev->ff;
496 ff->private = ml;
497 ff->upload = ml_ff_upload;
498 ff->playback = ml_ff_playback;
499 ff->set_gain = ml_ff_set_gain;
500 ff->destroy = ml_ff_destroy;
501
502 /* we can emulate periodic effects with RUMBLE */
503 if (test_bit(FF_RUMBLE, ff->ffbit)) {
504 set_bit(FF_PERIODIC, dev->ffbit);
505 set_bit(FF_SINE, dev->ffbit);
506 set_bit(FF_TRIANGLE, dev->ffbit);
507 set_bit(FF_SQUARE, dev->ffbit);
508 }
509
510 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
511 ml->states[i].effect = &ff->effects[i];
512
513 return 0;
514}
515EXPORT_SYMBOL_GPL(input_ff_create_memless);