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1 | /* |
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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
27 | |
28 | #include <linux/slab.h> |
29 | #include <linux/input.h> |
30 | #include <linux/module.h> |
31 | #include <linux/mutex.h> |
32 | #include <linux/spinlock.h> |
33 | #include <linux/jiffies.h> |
34 | #include <linux/fixp-arith.h> |
35 | |
36 | MODULE_LICENSE("GPL"); |
37 | MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>"); |
38 | MODULE_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 | |
50 | struct 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 | |
59 | struct ml_device { |
60 | void *private; |
61 | struct ml_effect_state states[FF_MEMLESS_EFFECTS]; |
62 | int gain; |
63 | struct timer_list timer; |
64 | struct input_dev *dev; |
65 | |
66 | int (*play_effect)(struct input_dev *dev, void *data, |
67 | struct ff_effect *effect); |
68 | }; |
69 | |
70 | static const struct ff_envelope *get_envelope(const struct ff_effect *effect) |
71 | { |
72 | static const struct ff_envelope empty_envelope; |
73 | |
74 | switch (effect->type) { |
75 | case FF_PERIODIC: |
76 | return &effect->u.periodic.envelope; |
77 | |
78 | case FF_CONSTANT: |
79 | return &effect->u.constant.envelope; |
80 | |
81 | default: |
82 | return &empty_envelope; |
83 | } |
84 | } |
85 | |
86 | /* |
87 | * Check for the next time envelope requires an update on memoryless devices |
88 | */ |
89 | static unsigned long calculate_next_time(struct ml_effect_state *state) |
90 | { |
91 | const struct ff_envelope *envelope = get_envelope(state->effect); |
92 | unsigned long attack_stop, fade_start, next_fade; |
93 | |
94 | if (envelope->attack_length) { |
95 | attack_stop = state->play_at + |
96 | msecs_to_jiffies(envelope->attack_length); |
97 | if (time_before(state->adj_at, attack_stop)) |
98 | return state->adj_at + |
99 | msecs_to_jiffies(FF_ENVELOPE_INTERVAL); |
100 | } |
101 | |
102 | if (state->effect->replay.length) { |
103 | if (envelope->fade_length) { |
104 | /* check when fading should start */ |
105 | fade_start = state->stop_at - |
106 | msecs_to_jiffies(envelope->fade_length); |
107 | |
108 | if (time_before(state->adj_at, fade_start)) |
109 | return fade_start; |
110 | |
111 | /* already fading, advance to next checkpoint */ |
112 | next_fade = state->adj_at + |
113 | msecs_to_jiffies(FF_ENVELOPE_INTERVAL); |
114 | if (time_before(next_fade, state->stop_at)) |
115 | return next_fade; |
116 | } |
117 | |
118 | return state->stop_at; |
119 | } |
120 | |
121 | return state->play_at; |
122 | } |
123 | |
124 | static void ml_schedule_timer(struct ml_device *ml) |
125 | { |
126 | struct ml_effect_state *state; |
127 | unsigned long now = jiffies; |
128 | unsigned long earliest = 0; |
129 | unsigned long next_at; |
130 | int events = 0; |
131 | int i; |
132 | |
133 | pr_debug("calculating next timer\n"); |
134 | |
135 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { |
136 | |
137 | state = &ml->states[i]; |
138 | |
139 | if (!test_bit(FF_EFFECT_STARTED, &state->flags)) |
140 | continue; |
141 | |
142 | if (test_bit(FF_EFFECT_PLAYING, &state->flags)) |
143 | next_at = calculate_next_time(state); |
144 | else |
145 | next_at = state->play_at; |
146 | |
147 | if (time_before_eq(now, next_at) && |
148 | (++events == 1 || time_before(next_at, earliest))) |
149 | earliest = next_at; |
150 | } |
151 | |
152 | if (!events) { |
153 | pr_debug("no actions\n"); |
154 | del_timer(&ml->timer); |
155 | } else { |
156 | pr_debug("timer set\n"); |
157 | mod_timer(&ml->timer, earliest); |
158 | } |
159 | } |
160 | |
161 | /* |
162 | * Apply an envelope to a value |
163 | */ |
164 | static int apply_envelope(struct ml_effect_state *state, int value, |
165 | struct ff_envelope *envelope) |
166 | { |
167 | struct ff_effect *effect = state->effect; |
168 | unsigned long now = jiffies; |
169 | int time_from_level; |
170 | int time_of_envelope; |
171 | int envelope_level; |
172 | int difference; |
173 | |
174 | if (envelope->attack_length && |
175 | time_before(now, |
176 | state->play_at + msecs_to_jiffies(envelope->attack_length))) { |
177 | pr_debug("value = 0x%x, attack_level = 0x%x\n", |
178 | value, envelope->attack_level); |
179 | time_from_level = jiffies_to_msecs(now - state->play_at); |
180 | time_of_envelope = envelope->attack_length; |
181 | envelope_level = min_t(u16, envelope->attack_level, 0x7fff); |
182 | |
183 | } else if (envelope->fade_length && effect->replay.length && |
184 | time_after(now, |
185 | state->stop_at - msecs_to_jiffies(envelope->fade_length)) && |
186 | time_before(now, state->stop_at)) { |
187 | time_from_level = jiffies_to_msecs(state->stop_at - now); |
188 | time_of_envelope = envelope->fade_length; |
189 | envelope_level = min_t(u16, envelope->fade_level, 0x7fff); |
190 | } else |
191 | return value; |
192 | |
193 | difference = abs(value) - envelope_level; |
194 | |
195 | pr_debug("difference = %d\n", difference); |
196 | pr_debug("time_from_level = 0x%x\n", time_from_level); |
197 | pr_debug("time_of_envelope = 0x%x\n", time_of_envelope); |
198 | |
199 | difference = difference * time_from_level / time_of_envelope; |
200 | |
201 | pr_debug("difference = %d\n", difference); |
202 | |
203 | return value < 0 ? |
204 | -(difference + envelope_level) : (difference + envelope_level); |
205 | } |
206 | |
207 | /* |
208 | * Return the type the effect has to be converted into (memless devices) |
209 | */ |
210 | static int get_compatible_type(struct ff_device *ff, int effect_type) |
211 | { |
212 | |
213 | if (test_bit(effect_type, ff->ffbit)) |
214 | return effect_type; |
215 | |
216 | if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit)) |
217 | return FF_RUMBLE; |
218 | |
219 | pr_err("invalid type in get_compatible_type()\n"); |
220 | |
221 | return 0; |
222 | } |
223 | |
224 | /* |
225 | * Only left/right direction should be used (under/over 0x8000) for |
226 | * forward/reverse motor direction (to keep calculation fast & simple). |
227 | */ |
228 | static u16 ml_calculate_direction(u16 direction, u16 force, |
229 | u16 new_direction, u16 new_force) |
230 | { |
231 | if (!force) |
232 | return new_direction; |
233 | if (!new_force) |
234 | return direction; |
235 | return (((u32)(direction >> 1) * force + |
236 | (new_direction >> 1) * new_force) / |
237 | (force + new_force)) << 1; |
238 | } |
239 | |
240 | /* |
241 | * Combine two effects and apply gain. |
242 | */ |
243 | static void ml_combine_effects(struct ff_effect *effect, |
244 | struct ml_effect_state *state, |
245 | int gain) |
246 | { |
247 | struct ff_effect *new = state->effect; |
248 | unsigned int strong, weak, i; |
249 | int x, y; |
250 | fixp_t level; |
251 | |
252 | switch (new->type) { |
253 | case FF_CONSTANT: |
254 | i = new->direction * 360 / 0xffff; |
255 | level = fixp_new16(apply_envelope(state, |
256 | new->u.constant.level, |
257 | &new->u.constant.envelope)); |
258 | x = fixp_mult(fixp_sin(i), level) * gain / 0xffff; |
259 | y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff; |
260 | /* |
261 | * here we abuse ff_ramp to hold x and y of constant force |
262 | * If in future any driver wants something else than x and y |
263 | * in s8, this should be changed to something more generic |
264 | */ |
265 | effect->u.ramp.start_level = |
266 | clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f); |
267 | effect->u.ramp.end_level = |
268 | clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f); |
269 | break; |
270 | |
271 | case FF_RUMBLE: |
272 | strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff; |
273 | weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff; |
274 | |
275 | if (effect->u.rumble.strong_magnitude + strong) |
276 | effect->direction = ml_calculate_direction( |
277 | effect->direction, |
278 | effect->u.rumble.strong_magnitude, |
279 | new->direction, strong); |
280 | else if (effect->u.rumble.weak_magnitude + weak) |
281 | effect->direction = ml_calculate_direction( |
282 | effect->direction, |
283 | effect->u.rumble.weak_magnitude, |
284 | new->direction, weak); |
285 | else |
286 | effect->direction = 0; |
287 | effect->u.rumble.strong_magnitude = |
288 | min(strong + effect->u.rumble.strong_magnitude, |
289 | 0xffffU); |
290 | effect->u.rumble.weak_magnitude = |
291 | min(weak + effect->u.rumble.weak_magnitude, 0xffffU); |
292 | break; |
293 | |
294 | case FF_PERIODIC: |
295 | i = apply_envelope(state, abs(new->u.periodic.magnitude), |
296 | &new->u.periodic.envelope); |
297 | |
298 | /* here we also scale it 0x7fff => 0xffff */ |
299 | i = i * gain / 0x7fff; |
300 | |
301 | if (effect->u.rumble.strong_magnitude + i) |
302 | effect->direction = ml_calculate_direction( |
303 | effect->direction, |
304 | effect->u.rumble.strong_magnitude, |
305 | new->direction, i); |
306 | else |
307 | effect->direction = 0; |
308 | effect->u.rumble.strong_magnitude = |
309 | min(i + effect->u.rumble.strong_magnitude, 0xffffU); |
310 | effect->u.rumble.weak_magnitude = |
311 | min(i + effect->u.rumble.weak_magnitude, 0xffffU); |
312 | break; |
313 | |
314 | default: |
315 | pr_err("invalid type in ml_combine_effects()\n"); |
316 | break; |
317 | } |
318 | |
319 | } |
320 | |
321 | |
322 | /* |
323 | * Because memoryless devices have only one effect per effect type active |
324 | * at one time we have to combine multiple effects into one |
325 | */ |
326 | static int ml_get_combo_effect(struct ml_device *ml, |
327 | unsigned long *effect_handled, |
328 | struct ff_effect *combo_effect) |
329 | { |
330 | struct ff_effect *effect; |
331 | struct ml_effect_state *state; |
332 | int effect_type; |
333 | int i; |
334 | |
335 | memset(combo_effect, 0, sizeof(struct ff_effect)); |
336 | |
337 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { |
338 | if (__test_and_set_bit(i, effect_handled)) |
339 | continue; |
340 | |
341 | state = &ml->states[i]; |
342 | effect = state->effect; |
343 | |
344 | if (!test_bit(FF_EFFECT_STARTED, &state->flags)) |
345 | continue; |
346 | |
347 | if (time_before(jiffies, state->play_at)) |
348 | continue; |
349 | |
350 | /* |
351 | * here we have started effects that are either |
352 | * currently playing (and may need be aborted) |
353 | * or need to start playing. |
354 | */ |
355 | effect_type = get_compatible_type(ml->dev->ff, effect->type); |
356 | if (combo_effect->type != effect_type) { |
357 | if (combo_effect->type != 0) { |
358 | __clear_bit(i, effect_handled); |
359 | continue; |
360 | } |
361 | combo_effect->type = effect_type; |
362 | } |
363 | |
364 | if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) { |
365 | __clear_bit(FF_EFFECT_PLAYING, &state->flags); |
366 | __clear_bit(FF_EFFECT_STARTED, &state->flags); |
367 | } else if (effect->replay.length && |
368 | time_after_eq(jiffies, state->stop_at)) { |
369 | |
370 | __clear_bit(FF_EFFECT_PLAYING, &state->flags); |
371 | |
372 | if (--state->count <= 0) { |
373 | __clear_bit(FF_EFFECT_STARTED, &state->flags); |
374 | } else { |
375 | state->play_at = jiffies + |
376 | msecs_to_jiffies(effect->replay.delay); |
377 | state->stop_at = state->play_at + |
378 | msecs_to_jiffies(effect->replay.length); |
379 | } |
380 | } else { |
381 | __set_bit(FF_EFFECT_PLAYING, &state->flags); |
382 | state->adj_at = jiffies; |
383 | ml_combine_effects(combo_effect, state, ml->gain); |
384 | } |
385 | } |
386 | |
387 | return combo_effect->type != 0; |
388 | } |
389 | |
390 | static void ml_play_effects(struct ml_device *ml) |
391 | { |
392 | struct ff_effect effect; |
393 | DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS); |
394 | |
395 | memset(handled_bm, 0, sizeof(handled_bm)); |
396 | |
397 | while (ml_get_combo_effect(ml, handled_bm, &effect)) |
398 | ml->play_effect(ml->dev, ml->private, &effect); |
399 | |
400 | ml_schedule_timer(ml); |
401 | } |
402 | |
403 | static void ml_effect_timer(unsigned long timer_data) |
404 | { |
405 | struct input_dev *dev = (struct input_dev *)timer_data; |
406 | struct ml_device *ml = dev->ff->private; |
407 | unsigned long flags; |
408 | |
409 | pr_debug("timer: updating effects\n"); |
410 | |
411 | spin_lock_irqsave(&dev->event_lock, flags); |
412 | ml_play_effects(ml); |
413 | spin_unlock_irqrestore(&dev->event_lock, flags); |
414 | } |
415 | |
416 | /* |
417 | * Sets requested gain for FF effects. Called with dev->event_lock held. |
418 | */ |
419 | static void ml_ff_set_gain(struct input_dev *dev, u16 gain) |
420 | { |
421 | struct ml_device *ml = dev->ff->private; |
422 | int i; |
423 | |
424 | ml->gain = gain; |
425 | |
426 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) |
427 | __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags); |
428 | |
429 | ml_play_effects(ml); |
430 | } |
431 | |
432 | /* |
433 | * Start/stop specified FF effect. Called with dev->event_lock held. |
434 | */ |
435 | static int ml_ff_playback(struct input_dev *dev, int effect_id, int value) |
436 | { |
437 | struct ml_device *ml = dev->ff->private; |
438 | struct ml_effect_state *state = &ml->states[effect_id]; |
439 | |
440 | if (value > 0) { |
441 | pr_debug("initiated play\n"); |
442 | |
443 | __set_bit(FF_EFFECT_STARTED, &state->flags); |
444 | state->count = value; |
445 | state->play_at = jiffies + |
446 | msecs_to_jiffies(state->effect->replay.delay); |
447 | state->stop_at = state->play_at + |
448 | msecs_to_jiffies(state->effect->replay.length); |
449 | state->adj_at = state->play_at; |
450 | |
451 | } else { |
452 | pr_debug("initiated stop\n"); |
453 | |
454 | if (test_bit(FF_EFFECT_PLAYING, &state->flags)) |
455 | __set_bit(FF_EFFECT_ABORTING, &state->flags); |
456 | else |
457 | __clear_bit(FF_EFFECT_STARTED, &state->flags); |
458 | } |
459 | |
460 | ml_play_effects(ml); |
461 | |
462 | return 0; |
463 | } |
464 | |
465 | static int ml_ff_upload(struct input_dev *dev, |
466 | struct ff_effect *effect, struct ff_effect *old) |
467 | { |
468 | struct ml_device *ml = dev->ff->private; |
469 | struct ml_effect_state *state = &ml->states[effect->id]; |
470 | |
471 | spin_lock_irq(&dev->event_lock); |
472 | |
473 | if (test_bit(FF_EFFECT_STARTED, &state->flags)) { |
474 | __clear_bit(FF_EFFECT_PLAYING, &state->flags); |
475 | state->play_at = jiffies + |
476 | msecs_to_jiffies(state->effect->replay.delay); |
477 | state->stop_at = state->play_at + |
478 | msecs_to_jiffies(state->effect->replay.length); |
479 | state->adj_at = state->play_at; |
480 | ml_schedule_timer(ml); |
481 | } |
482 | |
483 | spin_unlock_irq(&dev->event_lock); |
484 | |
485 | return 0; |
486 | } |
487 | |
488 | static void ml_ff_destroy(struct ff_device *ff) |
489 | { |
490 | struct ml_device *ml = ff->private; |
491 | |
492 | kfree(ml->private); |
493 | } |
494 | |
495 | /** |
496 | * input_ff_create_memless() - create memoryless force-feedback device |
497 | * @dev: input device supporting force-feedback |
498 | * @data: driver-specific data to be passed into @play_effect |
499 | * @play_effect: driver-specific method for playing FF effect |
500 | */ |
501 | int input_ff_create_memless(struct input_dev *dev, void *data, |
502 | int (*play_effect)(struct input_dev *, void *, struct ff_effect *)) |
503 | { |
504 | struct ml_device *ml; |
505 | struct ff_device *ff; |
506 | int error; |
507 | int i; |
508 | |
509 | ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL); |
510 | if (!ml) |
511 | return -ENOMEM; |
512 | |
513 | ml->dev = dev; |
514 | ml->private = data; |
515 | ml->play_effect = play_effect; |
516 | ml->gain = 0xffff; |
517 | setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev); |
518 | |
519 | set_bit(FF_GAIN, dev->ffbit); |
520 | |
521 | error = input_ff_create(dev, FF_MEMLESS_EFFECTS); |
522 | if (error) { |
523 | kfree(ml); |
524 | return error; |
525 | } |
526 | |
527 | ff = dev->ff; |
528 | ff->private = ml; |
529 | ff->upload = ml_ff_upload; |
530 | ff->playback = ml_ff_playback; |
531 | ff->set_gain = ml_ff_set_gain; |
532 | ff->destroy = ml_ff_destroy; |
533 | |
534 | /* we can emulate periodic effects with RUMBLE */ |
535 | if (test_bit(FF_RUMBLE, ff->ffbit)) { |
536 | set_bit(FF_PERIODIC, dev->ffbit); |
537 | set_bit(FF_SINE, dev->ffbit); |
538 | set_bit(FF_TRIANGLE, dev->ffbit); |
539 | set_bit(FF_SQUARE, dev->ffbit); |
540 | } |
541 | |
542 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) |
543 | ml->states[i].effect = &ff->effects[i]; |
544 | |
545 | return 0; |
546 | } |
547 | EXPORT_SYMBOL_GPL(input_ff_create_memless); |
548 |
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