1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Force feedback support for memoryless devices |
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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
12 | |
13 | #include <linux/slab.h> |
14 | #include <linux/input.h> |
15 | #include <linux/module.h> |
16 | #include <linux/mutex.h> |
17 | #include <linux/spinlock.h> |
18 | #include <linux/jiffies.h> |
19 | #include <linux/fixp-arith.h> |
20 | |
21 | MODULE_LICENSE("GPL" ); |
22 | MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>" ); |
23 | MODULE_DESCRIPTION("Force feedback support for memoryless devices" ); |
24 | |
25 | /* Number of effects handled with memoryless devices */ |
26 | #define FF_MEMLESS_EFFECTS 16 |
27 | |
28 | /* Envelope update interval in ms */ |
29 | #define FF_ENVELOPE_INTERVAL 50 |
30 | |
31 | #define FF_EFFECT_STARTED 0 |
32 | #define FF_EFFECT_PLAYING 1 |
33 | #define FF_EFFECT_ABORTING 2 |
34 | |
35 | struct ml_effect_state { |
36 | struct ff_effect *effect; |
37 | unsigned long flags; /* effect state (STARTED, PLAYING, etc) */ |
38 | int count; /* loop count of the effect */ |
39 | unsigned long play_at; /* start time */ |
40 | unsigned long stop_at; /* stop time */ |
41 | unsigned long adj_at; /* last time the effect was sent */ |
42 | }; |
43 | |
44 | struct ml_device { |
45 | void *private; |
46 | struct ml_effect_state states[FF_MEMLESS_EFFECTS]; |
47 | int gain; |
48 | struct timer_list timer; |
49 | struct input_dev *dev; |
50 | |
51 | int (*play_effect)(struct input_dev *dev, void *data, |
52 | struct ff_effect *effect); |
53 | }; |
54 | |
55 | static const struct ff_envelope *get_envelope(const struct ff_effect *effect) |
56 | { |
57 | static const struct ff_envelope empty_envelope; |
58 | |
59 | switch (effect->type) { |
60 | case FF_PERIODIC: |
61 | return &effect->u.periodic.envelope; |
62 | |
63 | case FF_CONSTANT: |
64 | return &effect->u.constant.envelope; |
65 | |
66 | default: |
67 | return &empty_envelope; |
68 | } |
69 | } |
70 | |
71 | /* |
72 | * Check for the next time envelope requires an update on memoryless devices |
73 | */ |
74 | static unsigned long calculate_next_time(struct ml_effect_state *state) |
75 | { |
76 | const struct ff_envelope *envelope = get_envelope(effect: state->effect); |
77 | unsigned long attack_stop, fade_start, next_fade; |
78 | |
79 | if (envelope->attack_length) { |
80 | attack_stop = state->play_at + |
81 | msecs_to_jiffies(m: envelope->attack_length); |
82 | if (time_before(state->adj_at, attack_stop)) |
83 | return state->adj_at + |
84 | msecs_to_jiffies(FF_ENVELOPE_INTERVAL); |
85 | } |
86 | |
87 | if (state->effect->replay.length) { |
88 | if (envelope->fade_length) { |
89 | /* check when fading should start */ |
90 | fade_start = state->stop_at - |
91 | msecs_to_jiffies(m: envelope->fade_length); |
92 | |
93 | if (time_before(state->adj_at, fade_start)) |
94 | return fade_start; |
95 | |
96 | /* already fading, advance to next checkpoint */ |
97 | next_fade = state->adj_at + |
98 | msecs_to_jiffies(FF_ENVELOPE_INTERVAL); |
99 | if (time_before(next_fade, state->stop_at)) |
100 | return next_fade; |
101 | } |
102 | |
103 | return state->stop_at; |
104 | } |
105 | |
106 | return state->play_at; |
107 | } |
108 | |
109 | static void ml_schedule_timer(struct ml_device *ml) |
110 | { |
111 | struct ml_effect_state *state; |
112 | unsigned long now = jiffies; |
113 | unsigned long earliest = 0; |
114 | unsigned long next_at; |
115 | int events = 0; |
116 | int i; |
117 | |
118 | pr_debug("calculating next timer\n" ); |
119 | |
120 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { |
121 | |
122 | state = &ml->states[i]; |
123 | |
124 | if (!test_bit(FF_EFFECT_STARTED, &state->flags)) |
125 | continue; |
126 | |
127 | if (test_bit(FF_EFFECT_PLAYING, &state->flags)) |
128 | next_at = calculate_next_time(state); |
129 | else |
130 | next_at = state->play_at; |
131 | |
132 | if (time_before_eq(now, next_at) && |
133 | (++events == 1 || time_before(next_at, earliest))) |
134 | earliest = next_at; |
135 | } |
136 | |
137 | if (!events) { |
138 | pr_debug("no actions\n" ); |
139 | del_timer(timer: &ml->timer); |
140 | } else { |
141 | pr_debug("timer set\n" ); |
142 | mod_timer(timer: &ml->timer, expires: earliest); |
143 | } |
144 | } |
145 | |
146 | /* |
147 | * Apply an envelope to a value |
148 | */ |
149 | static int apply_envelope(struct ml_effect_state *state, int value, |
150 | struct ff_envelope *envelope) |
151 | { |
152 | struct ff_effect *effect = state->effect; |
153 | unsigned long now = jiffies; |
154 | int time_from_level; |
155 | int time_of_envelope; |
156 | int envelope_level; |
157 | int difference; |
158 | |
159 | if (envelope->attack_length && |
160 | time_before(now, |
161 | state->play_at + msecs_to_jiffies(envelope->attack_length))) { |
162 | pr_debug("value = 0x%x, attack_level = 0x%x\n" , |
163 | value, envelope->attack_level); |
164 | time_from_level = jiffies_to_msecs(j: now - state->play_at); |
165 | time_of_envelope = envelope->attack_length; |
166 | envelope_level = min_t(u16, envelope->attack_level, 0x7fff); |
167 | |
168 | } else if (envelope->fade_length && effect->replay.length && |
169 | time_after(now, |
170 | state->stop_at - msecs_to_jiffies(envelope->fade_length)) && |
171 | time_before(now, state->stop_at)) { |
172 | time_from_level = jiffies_to_msecs(j: state->stop_at - now); |
173 | time_of_envelope = envelope->fade_length; |
174 | envelope_level = min_t(u16, envelope->fade_level, 0x7fff); |
175 | } else |
176 | return value; |
177 | |
178 | difference = abs(value) - envelope_level; |
179 | |
180 | pr_debug("difference = %d\n" , difference); |
181 | pr_debug("time_from_level = 0x%x\n" , time_from_level); |
182 | pr_debug("time_of_envelope = 0x%x\n" , time_of_envelope); |
183 | |
184 | difference = difference * time_from_level / time_of_envelope; |
185 | |
186 | pr_debug("difference = %d\n" , difference); |
187 | |
188 | return value < 0 ? |
189 | -(difference + envelope_level) : (difference + envelope_level); |
190 | } |
191 | |
192 | /* |
193 | * Return the type the effect has to be converted into (memless devices) |
194 | */ |
195 | static int get_compatible_type(struct ff_device *ff, int effect_type) |
196 | { |
197 | |
198 | if (test_bit(effect_type, ff->ffbit)) |
199 | return effect_type; |
200 | |
201 | if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit)) |
202 | return FF_RUMBLE; |
203 | |
204 | pr_err("invalid type in get_compatible_type()\n" ); |
205 | |
206 | return 0; |
207 | } |
208 | |
209 | /* |
210 | * Only left/right direction should be used (under/over 0x8000) for |
211 | * forward/reverse motor direction (to keep calculation fast & simple). |
212 | */ |
213 | static u16 ml_calculate_direction(u16 direction, u16 force, |
214 | u16 new_direction, u16 new_force) |
215 | { |
216 | if (!force) |
217 | return new_direction; |
218 | if (!new_force) |
219 | return direction; |
220 | return (((u32)(direction >> 1) * force + |
221 | (new_direction >> 1) * new_force) / |
222 | (force + new_force)) << 1; |
223 | } |
224 | |
225 | #define FRAC_N 8 |
226 | static inline s16 fixp_new16(s16 a) |
227 | { |
228 | return ((s32)a) >> (16 - FRAC_N); |
229 | } |
230 | |
231 | static inline s16 fixp_mult(s16 a, s16 b) |
232 | { |
233 | a = ((s32)a * 0x100) / 0x7fff; |
234 | return ((s32)(a * b)) >> FRAC_N; |
235 | } |
236 | |
237 | /* |
238 | * Combine two effects and apply gain. |
239 | */ |
240 | static void ml_combine_effects(struct ff_effect *effect, |
241 | struct ml_effect_state *state, |
242 | int gain) |
243 | { |
244 | struct ff_effect *new = state->effect; |
245 | unsigned int strong, weak, i; |
246 | int x, y; |
247 | s16 level; |
248 | |
249 | switch (new->type) { |
250 | case FF_CONSTANT: |
251 | i = new->direction * 360 / 0xffff; |
252 | level = fixp_new16(a: apply_envelope(state, |
253 | value: new->u.constant.level, |
254 | envelope: &new->u.constant.envelope)); |
255 | x = fixp_mult(fixp_sin16(i), b: level) * gain / 0xffff; |
256 | y = fixp_mult(a: -fixp_cos16(i), b: level) * gain / 0xffff; |
257 | /* |
258 | * here we abuse ff_ramp to hold x and y of constant force |
259 | * If in future any driver wants something else than x and y |
260 | * in s8, this should be changed to something more generic |
261 | */ |
262 | effect->u.ramp.start_level = |
263 | clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f); |
264 | effect->u.ramp.end_level = |
265 | clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f); |
266 | break; |
267 | |
268 | case FF_RUMBLE: |
269 | strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff; |
270 | weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff; |
271 | |
272 | if (effect->u.rumble.strong_magnitude + strong) |
273 | effect->direction = ml_calculate_direction( |
274 | direction: effect->direction, |
275 | force: effect->u.rumble.strong_magnitude, |
276 | new_direction: new->direction, new_force: strong); |
277 | else if (effect->u.rumble.weak_magnitude + weak) |
278 | effect->direction = ml_calculate_direction( |
279 | direction: effect->direction, |
280 | force: effect->u.rumble.weak_magnitude, |
281 | new_direction: new->direction, new_force: weak); |
282 | else |
283 | effect->direction = 0; |
284 | effect->u.rumble.strong_magnitude = |
285 | min(strong + effect->u.rumble.strong_magnitude, |
286 | 0xffffU); |
287 | effect->u.rumble.weak_magnitude = |
288 | min(weak + effect->u.rumble.weak_magnitude, 0xffffU); |
289 | break; |
290 | |
291 | case FF_PERIODIC: |
292 | i = apply_envelope(state, abs(new->u.periodic.magnitude), |
293 | envelope: &new->u.periodic.envelope); |
294 | |
295 | /* here we also scale it 0x7fff => 0xffff */ |
296 | i = i * gain / 0x7fff; |
297 | |
298 | if (effect->u.rumble.strong_magnitude + i) |
299 | effect->direction = ml_calculate_direction( |
300 | direction: effect->direction, |
301 | force: effect->u.rumble.strong_magnitude, |
302 | new_direction: new->direction, new_force: i); |
303 | else |
304 | effect->direction = 0; |
305 | effect->u.rumble.strong_magnitude = |
306 | min(i + effect->u.rumble.strong_magnitude, 0xffffU); |
307 | effect->u.rumble.weak_magnitude = |
308 | min(i + effect->u.rumble.weak_magnitude, 0xffffU); |
309 | break; |
310 | |
311 | default: |
312 | pr_err("invalid type in ml_combine_effects()\n" ); |
313 | break; |
314 | } |
315 | |
316 | } |
317 | |
318 | |
319 | /* |
320 | * Because memoryless devices have only one effect per effect type active |
321 | * at one time we have to combine multiple effects into one |
322 | */ |
323 | static int ml_get_combo_effect(struct ml_device *ml, |
324 | unsigned long *effect_handled, |
325 | struct ff_effect *combo_effect) |
326 | { |
327 | struct ff_effect *effect; |
328 | struct ml_effect_state *state; |
329 | int effect_type; |
330 | int i; |
331 | |
332 | memset(combo_effect, 0, sizeof(struct ff_effect)); |
333 | |
334 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { |
335 | if (__test_and_set_bit(i, effect_handled)) |
336 | continue; |
337 | |
338 | state = &ml->states[i]; |
339 | effect = state->effect; |
340 | |
341 | if (!test_bit(FF_EFFECT_STARTED, &state->flags)) |
342 | continue; |
343 | |
344 | if (time_before(jiffies, state->play_at)) |
345 | continue; |
346 | |
347 | /* |
348 | * here we have started effects that are either |
349 | * currently playing (and may need be aborted) |
350 | * or need to start playing. |
351 | */ |
352 | effect_type = get_compatible_type(ff: ml->dev->ff, effect_type: effect->type); |
353 | if (combo_effect->type != effect_type) { |
354 | if (combo_effect->type != 0) { |
355 | __clear_bit(i, effect_handled); |
356 | continue; |
357 | } |
358 | combo_effect->type = effect_type; |
359 | } |
360 | |
361 | if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) { |
362 | __clear_bit(FF_EFFECT_PLAYING, &state->flags); |
363 | __clear_bit(FF_EFFECT_STARTED, &state->flags); |
364 | } else if (effect->replay.length && |
365 | time_after_eq(jiffies, state->stop_at)) { |
366 | |
367 | __clear_bit(FF_EFFECT_PLAYING, &state->flags); |
368 | |
369 | if (--state->count <= 0) { |
370 | __clear_bit(FF_EFFECT_STARTED, &state->flags); |
371 | } else { |
372 | state->play_at = jiffies + |
373 | msecs_to_jiffies(m: effect->replay.delay); |
374 | state->stop_at = state->play_at + |
375 | msecs_to_jiffies(m: effect->replay.length); |
376 | } |
377 | } else { |
378 | __set_bit(FF_EFFECT_PLAYING, &state->flags); |
379 | state->adj_at = jiffies; |
380 | ml_combine_effects(effect: combo_effect, state, gain: ml->gain); |
381 | } |
382 | } |
383 | |
384 | return combo_effect->type != 0; |
385 | } |
386 | |
387 | static void ml_play_effects(struct ml_device *ml) |
388 | { |
389 | struct ff_effect effect; |
390 | DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS); |
391 | |
392 | memset(handled_bm, 0, sizeof(handled_bm)); |
393 | |
394 | while (ml_get_combo_effect(ml, effect_handled: handled_bm, combo_effect: &effect)) |
395 | ml->play_effect(ml->dev, ml->private, &effect); |
396 | |
397 | ml_schedule_timer(ml); |
398 | } |
399 | |
400 | static void ml_effect_timer(struct timer_list *t) |
401 | { |
402 | struct ml_device *ml = from_timer(ml, t, timer); |
403 | struct input_dev *dev = ml->dev; |
404 | unsigned long flags; |
405 | |
406 | pr_debug("timer: updating effects\n" ); |
407 | |
408 | spin_lock_irqsave(&dev->event_lock, flags); |
409 | ml_play_effects(ml); |
410 | spin_unlock_irqrestore(lock: &dev->event_lock, flags); |
411 | } |
412 | |
413 | /* |
414 | * Sets requested gain for FF effects. Called with dev->event_lock held. |
415 | */ |
416 | static void ml_ff_set_gain(struct input_dev *dev, u16 gain) |
417 | { |
418 | struct ml_device *ml = dev->ff->private; |
419 | int i; |
420 | |
421 | ml->gain = gain; |
422 | |
423 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) |
424 | __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags); |
425 | |
426 | ml_play_effects(ml); |
427 | } |
428 | |
429 | /* |
430 | * Start/stop specified FF effect. Called with dev->event_lock held. |
431 | */ |
432 | static int ml_ff_playback(struct input_dev *dev, int effect_id, int value) |
433 | { |
434 | struct ml_device *ml = dev->ff->private; |
435 | struct ml_effect_state *state = &ml->states[effect_id]; |
436 | |
437 | if (value > 0) { |
438 | pr_debug("initiated play\n" ); |
439 | |
440 | __set_bit(FF_EFFECT_STARTED, &state->flags); |
441 | state->count = value; |
442 | state->play_at = jiffies + |
443 | msecs_to_jiffies(m: state->effect->replay.delay); |
444 | state->stop_at = state->play_at + |
445 | msecs_to_jiffies(m: state->effect->replay.length); |
446 | state->adj_at = state->play_at; |
447 | |
448 | } else { |
449 | pr_debug("initiated stop\n" ); |
450 | |
451 | if (test_bit(FF_EFFECT_PLAYING, &state->flags)) |
452 | __set_bit(FF_EFFECT_ABORTING, &state->flags); |
453 | else |
454 | __clear_bit(FF_EFFECT_STARTED, &state->flags); |
455 | } |
456 | |
457 | ml_play_effects(ml); |
458 | |
459 | return 0; |
460 | } |
461 | |
462 | static int ml_ff_upload(struct input_dev *dev, |
463 | struct ff_effect *effect, struct ff_effect *old) |
464 | { |
465 | struct ml_device *ml = dev->ff->private; |
466 | struct ml_effect_state *state = &ml->states[effect->id]; |
467 | |
468 | spin_lock_irq(lock: &dev->event_lock); |
469 | |
470 | if (test_bit(FF_EFFECT_STARTED, &state->flags)) { |
471 | __clear_bit(FF_EFFECT_PLAYING, &state->flags); |
472 | state->play_at = jiffies + |
473 | msecs_to_jiffies(m: state->effect->replay.delay); |
474 | state->stop_at = state->play_at + |
475 | msecs_to_jiffies(m: state->effect->replay.length); |
476 | state->adj_at = state->play_at; |
477 | ml_schedule_timer(ml); |
478 | } |
479 | |
480 | spin_unlock_irq(lock: &dev->event_lock); |
481 | |
482 | return 0; |
483 | } |
484 | |
485 | static void ml_ff_destroy(struct ff_device *ff) |
486 | { |
487 | struct ml_device *ml = ff->private; |
488 | |
489 | /* |
490 | * Even though we stop all playing effects when tearing down |
491 | * an input device (via input_device_flush() that calls into |
492 | * input_ff_flush() that stops and erases all effects), we |
493 | * do not actually stop the timer, and therefore we should |
494 | * do it here. |
495 | */ |
496 | del_timer_sync(timer: &ml->timer); |
497 | |
498 | kfree(objp: ml->private); |
499 | } |
500 | |
501 | /** |
502 | * input_ff_create_memless() - create memoryless force-feedback device |
503 | * @dev: input device supporting force-feedback |
504 | * @data: driver-specific data to be passed into @play_effect |
505 | * @play_effect: driver-specific method for playing FF effect |
506 | */ |
507 | int input_ff_create_memless(struct input_dev *dev, void *data, |
508 | int (*play_effect)(struct input_dev *, void *, struct ff_effect *)) |
509 | { |
510 | struct ml_device *ml; |
511 | struct ff_device *ff; |
512 | int error; |
513 | int i; |
514 | |
515 | ml = kzalloc(size: sizeof(struct ml_device), GFP_KERNEL); |
516 | if (!ml) |
517 | return -ENOMEM; |
518 | |
519 | ml->dev = dev; |
520 | ml->private = data; |
521 | ml->play_effect = play_effect; |
522 | ml->gain = 0xffff; |
523 | timer_setup(&ml->timer, ml_effect_timer, 0); |
524 | |
525 | set_bit(FF_GAIN, addr: dev->ffbit); |
526 | |
527 | error = input_ff_create(dev, FF_MEMLESS_EFFECTS); |
528 | if (error) { |
529 | kfree(objp: ml); |
530 | return error; |
531 | } |
532 | |
533 | ff = dev->ff; |
534 | ff->private = ml; |
535 | ff->upload = ml_ff_upload; |
536 | ff->playback = ml_ff_playback; |
537 | ff->set_gain = ml_ff_set_gain; |
538 | ff->destroy = ml_ff_destroy; |
539 | |
540 | /* we can emulate periodic effects with RUMBLE */ |
541 | if (test_bit(FF_RUMBLE, ff->ffbit)) { |
542 | set_bit(FF_PERIODIC, addr: dev->ffbit); |
543 | set_bit(FF_SINE, addr: dev->ffbit); |
544 | set_bit(FF_TRIANGLE, addr: dev->ffbit); |
545 | set_bit(FF_SQUARE, addr: dev->ffbit); |
546 | } |
547 | |
548 | for (i = 0; i < FF_MEMLESS_EFFECTS; i++) |
549 | ml->states[i].effect = &ff->effects[i]; |
550 | |
551 | return 0; |
552 | } |
553 | EXPORT_SYMBOL_GPL(input_ff_create_memless); |
554 | |