ff-memless.c 14 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553
  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * Force feedback support for memoryless devices
  4. *
  5. * Copyright (c) 2006 Anssi Hannula <[email protected]>
  6. * Copyright (c) 2006 Dmitry Torokhov <[email protected]>
  7. */
  8. /* #define DEBUG */
  9. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10. #include <linux/slab.h>
  11. #include <linux/input.h>
  12. #include <linux/module.h>
  13. #include <linux/mutex.h>
  14. #include <linux/spinlock.h>
  15. #include <linux/jiffies.h>
  16. #include <linux/fixp-arith.h>
  17. MODULE_LICENSE("GPL");
  18. MODULE_AUTHOR("Anssi Hannula <[email protected]>");
  19. MODULE_DESCRIPTION("Force feedback support for memoryless devices");
  20. /* Number of effects handled with memoryless devices */
  21. #define FF_MEMLESS_EFFECTS 16
  22. /* Envelope update interval in ms */
  23. #define FF_ENVELOPE_INTERVAL 50
  24. #define FF_EFFECT_STARTED 0
  25. #define FF_EFFECT_PLAYING 1
  26. #define FF_EFFECT_ABORTING 2
  27. struct ml_effect_state {
  28. struct ff_effect *effect;
  29. unsigned long flags; /* effect state (STARTED, PLAYING, etc) */
  30. int count; /* loop count of the effect */
  31. unsigned long play_at; /* start time */
  32. unsigned long stop_at; /* stop time */
  33. unsigned long adj_at; /* last time the effect was sent */
  34. };
  35. struct ml_device {
  36. void *private;
  37. struct ml_effect_state states[FF_MEMLESS_EFFECTS];
  38. int gain;
  39. struct timer_list timer;
  40. struct input_dev *dev;
  41. int (*play_effect)(struct input_dev *dev, void *data,
  42. struct ff_effect *effect);
  43. };
  44. static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
  45. {
  46. static const struct ff_envelope empty_envelope;
  47. switch (effect->type) {
  48. case FF_PERIODIC:
  49. return &effect->u.periodic.envelope;
  50. case FF_CONSTANT:
  51. return &effect->u.constant.envelope;
  52. default:
  53. return &empty_envelope;
  54. }
  55. }
  56. /*
  57. * Check for the next time envelope requires an update on memoryless devices
  58. */
  59. static unsigned long calculate_next_time(struct ml_effect_state *state)
  60. {
  61. const struct ff_envelope *envelope = get_envelope(state->effect);
  62. unsigned long attack_stop, fade_start, next_fade;
  63. if (envelope->attack_length) {
  64. attack_stop = state->play_at +
  65. msecs_to_jiffies(envelope->attack_length);
  66. if (time_before(state->adj_at, attack_stop))
  67. return state->adj_at +
  68. msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
  69. }
  70. if (state->effect->replay.length) {
  71. if (envelope->fade_length) {
  72. /* check when fading should start */
  73. fade_start = state->stop_at -
  74. msecs_to_jiffies(envelope->fade_length);
  75. if (time_before(state->adj_at, fade_start))
  76. return fade_start;
  77. /* already fading, advance to next checkpoint */
  78. next_fade = state->adj_at +
  79. msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
  80. if (time_before(next_fade, state->stop_at))
  81. return next_fade;
  82. }
  83. return state->stop_at;
  84. }
  85. return state->play_at;
  86. }
  87. static void ml_schedule_timer(struct ml_device *ml)
  88. {
  89. struct ml_effect_state *state;
  90. unsigned long now = jiffies;
  91. unsigned long earliest = 0;
  92. unsigned long next_at;
  93. int events = 0;
  94. int i;
  95. pr_debug("calculating next timer\n");
  96. for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
  97. state = &ml->states[i];
  98. if (!test_bit(FF_EFFECT_STARTED, &state->flags))
  99. continue;
  100. if (test_bit(FF_EFFECT_PLAYING, &state->flags))
  101. next_at = calculate_next_time(state);
  102. else
  103. next_at = state->play_at;
  104. if (time_before_eq(now, next_at) &&
  105. (++events == 1 || time_before(next_at, earliest)))
  106. earliest = next_at;
  107. }
  108. if (!events) {
  109. pr_debug("no actions\n");
  110. del_timer(&ml->timer);
  111. } else {
  112. pr_debug("timer set\n");
  113. mod_timer(&ml->timer, earliest);
  114. }
  115. }
  116. /*
  117. * Apply an envelope to a value
  118. */
  119. static int apply_envelope(struct ml_effect_state *state, int value,
  120. struct ff_envelope *envelope)
  121. {
  122. struct ff_effect *effect = state->effect;
  123. unsigned long now = jiffies;
  124. int time_from_level;
  125. int time_of_envelope;
  126. int envelope_level;
  127. int difference;
  128. if (envelope->attack_length &&
  129. time_before(now,
  130. state->play_at + msecs_to_jiffies(envelope->attack_length))) {
  131. pr_debug("value = 0x%x, attack_level = 0x%x\n",
  132. value, envelope->attack_level);
  133. time_from_level = jiffies_to_msecs(now - state->play_at);
  134. time_of_envelope = envelope->attack_length;
  135. envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
  136. } else if (envelope->fade_length && effect->replay.length &&
  137. time_after(now,
  138. state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
  139. time_before(now, state->stop_at)) {
  140. time_from_level = jiffies_to_msecs(state->stop_at - now);
  141. time_of_envelope = envelope->fade_length;
  142. envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
  143. } else
  144. return value;
  145. difference = abs(value) - envelope_level;
  146. pr_debug("difference = %d\n", difference);
  147. pr_debug("time_from_level = 0x%x\n", time_from_level);
  148. pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
  149. difference = difference * time_from_level / time_of_envelope;
  150. pr_debug("difference = %d\n", difference);
  151. return value < 0 ?
  152. -(difference + envelope_level) : (difference + envelope_level);
  153. }
  154. /*
  155. * Return the type the effect has to be converted into (memless devices)
  156. */
  157. static int get_compatible_type(struct ff_device *ff, int effect_type)
  158. {
  159. if (test_bit(effect_type, ff->ffbit))
  160. return effect_type;
  161. if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
  162. return FF_RUMBLE;
  163. pr_err("invalid type in get_compatible_type()\n");
  164. return 0;
  165. }
  166. /*
  167. * Only left/right direction should be used (under/over 0x8000) for
  168. * forward/reverse motor direction (to keep calculation fast & simple).
  169. */
  170. static u16 ml_calculate_direction(u16 direction, u16 force,
  171. u16 new_direction, u16 new_force)
  172. {
  173. if (!force)
  174. return new_direction;
  175. if (!new_force)
  176. return direction;
  177. return (((u32)(direction >> 1) * force +
  178. (new_direction >> 1) * new_force) /
  179. (force + new_force)) << 1;
  180. }
  181. #define FRAC_N 8
  182. static inline s16 fixp_new16(s16 a)
  183. {
  184. return ((s32)a) >> (16 - FRAC_N);
  185. }
  186. static inline s16 fixp_mult(s16 a, s16 b)
  187. {
  188. a = ((s32)a * 0x100) / 0x7fff;
  189. return ((s32)(a * b)) >> FRAC_N;
  190. }
  191. /*
  192. * Combine two effects and apply gain.
  193. */
  194. static void ml_combine_effects(struct ff_effect *effect,
  195. struct ml_effect_state *state,
  196. int gain)
  197. {
  198. struct ff_effect *new = state->effect;
  199. unsigned int strong, weak, i;
  200. int x, y;
  201. s16 level;
  202. switch (new->type) {
  203. case FF_CONSTANT:
  204. i = new->direction * 360 / 0xffff;
  205. level = fixp_new16(apply_envelope(state,
  206. new->u.constant.level,
  207. &new->u.constant.envelope));
  208. x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
  209. y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
  210. /*
  211. * here we abuse ff_ramp to hold x and y of constant force
  212. * If in future any driver wants something else than x and y
  213. * in s8, this should be changed to something more generic
  214. */
  215. effect->u.ramp.start_level =
  216. clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
  217. effect->u.ramp.end_level =
  218. clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
  219. break;
  220. case FF_RUMBLE:
  221. strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
  222. weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
  223. if (effect->u.rumble.strong_magnitude + strong)
  224. effect->direction = ml_calculate_direction(
  225. effect->direction,
  226. effect->u.rumble.strong_magnitude,
  227. new->direction, strong);
  228. else if (effect->u.rumble.weak_magnitude + weak)
  229. effect->direction = ml_calculate_direction(
  230. effect->direction,
  231. effect->u.rumble.weak_magnitude,
  232. new->direction, weak);
  233. else
  234. effect->direction = 0;
  235. effect->u.rumble.strong_magnitude =
  236. min(strong + effect->u.rumble.strong_magnitude,
  237. 0xffffU);
  238. effect->u.rumble.weak_magnitude =
  239. min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
  240. break;
  241. case FF_PERIODIC:
  242. i = apply_envelope(state, abs(new->u.periodic.magnitude),
  243. &new->u.periodic.envelope);
  244. /* here we also scale it 0x7fff => 0xffff */
  245. i = i * gain / 0x7fff;
  246. if (effect->u.rumble.strong_magnitude + i)
  247. effect->direction = ml_calculate_direction(
  248. effect->direction,
  249. effect->u.rumble.strong_magnitude,
  250. new->direction, i);
  251. else
  252. effect->direction = 0;
  253. effect->u.rumble.strong_magnitude =
  254. min(i + effect->u.rumble.strong_magnitude, 0xffffU);
  255. effect->u.rumble.weak_magnitude =
  256. min(i + effect->u.rumble.weak_magnitude, 0xffffU);
  257. break;
  258. default:
  259. pr_err("invalid type in ml_combine_effects()\n");
  260. break;
  261. }
  262. }
  263. /*
  264. * Because memoryless devices have only one effect per effect type active
  265. * at one time we have to combine multiple effects into one
  266. */
  267. static int ml_get_combo_effect(struct ml_device *ml,
  268. unsigned long *effect_handled,
  269. struct ff_effect *combo_effect)
  270. {
  271. struct ff_effect *effect;
  272. struct ml_effect_state *state;
  273. int effect_type;
  274. int i;
  275. memset(combo_effect, 0, sizeof(struct ff_effect));
  276. for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
  277. if (__test_and_set_bit(i, effect_handled))
  278. continue;
  279. state = &ml->states[i];
  280. effect = state->effect;
  281. if (!test_bit(FF_EFFECT_STARTED, &state->flags))
  282. continue;
  283. if (time_before(jiffies, state->play_at))
  284. continue;
  285. /*
  286. * here we have started effects that are either
  287. * currently playing (and may need be aborted)
  288. * or need to start playing.
  289. */
  290. effect_type = get_compatible_type(ml->dev->ff, effect->type);
  291. if (combo_effect->type != effect_type) {
  292. if (combo_effect->type != 0) {
  293. __clear_bit(i, effect_handled);
  294. continue;
  295. }
  296. combo_effect->type = effect_type;
  297. }
  298. if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
  299. __clear_bit(FF_EFFECT_PLAYING, &state->flags);
  300. __clear_bit(FF_EFFECT_STARTED, &state->flags);
  301. } else if (effect->replay.length &&
  302. time_after_eq(jiffies, state->stop_at)) {
  303. __clear_bit(FF_EFFECT_PLAYING, &state->flags);
  304. if (--state->count <= 0) {
  305. __clear_bit(FF_EFFECT_STARTED, &state->flags);
  306. } else {
  307. state->play_at = jiffies +
  308. msecs_to_jiffies(effect->replay.delay);
  309. state->stop_at = state->play_at +
  310. msecs_to_jiffies(effect->replay.length);
  311. }
  312. } else {
  313. __set_bit(FF_EFFECT_PLAYING, &state->flags);
  314. state->adj_at = jiffies;
  315. ml_combine_effects(combo_effect, state, ml->gain);
  316. }
  317. }
  318. return combo_effect->type != 0;
  319. }
  320. static void ml_play_effects(struct ml_device *ml)
  321. {
  322. struct ff_effect effect;
  323. DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
  324. memset(handled_bm, 0, sizeof(handled_bm));
  325. while (ml_get_combo_effect(ml, handled_bm, &effect))
  326. ml->play_effect(ml->dev, ml->private, &effect);
  327. ml_schedule_timer(ml);
  328. }
  329. static void ml_effect_timer(struct timer_list *t)
  330. {
  331. struct ml_device *ml = from_timer(ml, t, timer);
  332. struct input_dev *dev = ml->dev;
  333. unsigned long flags;
  334. pr_debug("timer: updating effects\n");
  335. spin_lock_irqsave(&dev->event_lock, flags);
  336. ml_play_effects(ml);
  337. spin_unlock_irqrestore(&dev->event_lock, flags);
  338. }
  339. /*
  340. * Sets requested gain for FF effects. Called with dev->event_lock held.
  341. */
  342. static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
  343. {
  344. struct ml_device *ml = dev->ff->private;
  345. int i;
  346. ml->gain = gain;
  347. for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
  348. __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
  349. ml_play_effects(ml);
  350. }
  351. /*
  352. * Start/stop specified FF effect. Called with dev->event_lock held.
  353. */
  354. static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
  355. {
  356. struct ml_device *ml = dev->ff->private;
  357. struct ml_effect_state *state = &ml->states[effect_id];
  358. if (value > 0) {
  359. pr_debug("initiated play\n");
  360. __set_bit(FF_EFFECT_STARTED, &state->flags);
  361. state->count = value;
  362. state->play_at = jiffies +
  363. msecs_to_jiffies(state->effect->replay.delay);
  364. state->stop_at = state->play_at +
  365. msecs_to_jiffies(state->effect->replay.length);
  366. state->adj_at = state->play_at;
  367. } else {
  368. pr_debug("initiated stop\n");
  369. if (test_bit(FF_EFFECT_PLAYING, &state->flags))
  370. __set_bit(FF_EFFECT_ABORTING, &state->flags);
  371. else
  372. __clear_bit(FF_EFFECT_STARTED, &state->flags);
  373. }
  374. ml_play_effects(ml);
  375. return 0;
  376. }
  377. static int ml_ff_upload(struct input_dev *dev,
  378. struct ff_effect *effect, struct ff_effect *old)
  379. {
  380. struct ml_device *ml = dev->ff->private;
  381. struct ml_effect_state *state = &ml->states[effect->id];
  382. spin_lock_irq(&dev->event_lock);
  383. if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
  384. __clear_bit(FF_EFFECT_PLAYING, &state->flags);
  385. state->play_at = jiffies +
  386. msecs_to_jiffies(state->effect->replay.delay);
  387. state->stop_at = state->play_at +
  388. msecs_to_jiffies(state->effect->replay.length);
  389. state->adj_at = state->play_at;
  390. ml_schedule_timer(ml);
  391. }
  392. spin_unlock_irq(&dev->event_lock);
  393. return 0;
  394. }
  395. static void ml_ff_destroy(struct ff_device *ff)
  396. {
  397. struct ml_device *ml = ff->private;
  398. /*
  399. * Even though we stop all playing effects when tearing down
  400. * an input device (via input_device_flush() that calls into
  401. * input_ff_flush() that stops and erases all effects), we
  402. * do not actually stop the timer, and therefore we should
  403. * do it here.
  404. */
  405. del_timer_sync(&ml->timer);
  406. kfree(ml->private);
  407. }
  408. /**
  409. * input_ff_create_memless() - create memoryless force-feedback device
  410. * @dev: input device supporting force-feedback
  411. * @data: driver-specific data to be passed into @play_effect
  412. * @play_effect: driver-specific method for playing FF effect
  413. */
  414. int input_ff_create_memless(struct input_dev *dev, void *data,
  415. int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
  416. {
  417. struct ml_device *ml;
  418. struct ff_device *ff;
  419. int error;
  420. int i;
  421. ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
  422. if (!ml)
  423. return -ENOMEM;
  424. ml->dev = dev;
  425. ml->private = data;
  426. ml->play_effect = play_effect;
  427. ml->gain = 0xffff;
  428. timer_setup(&ml->timer, ml_effect_timer, 0);
  429. set_bit(FF_GAIN, dev->ffbit);
  430. error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
  431. if (error) {
  432. kfree(ml);
  433. return error;
  434. }
  435. ff = dev->ff;
  436. ff->private = ml;
  437. ff->upload = ml_ff_upload;
  438. ff->playback = ml_ff_playback;
  439. ff->set_gain = ml_ff_set_gain;
  440. ff->destroy = ml_ff_destroy;
  441. /* we can emulate periodic effects with RUMBLE */
  442. if (test_bit(FF_RUMBLE, ff->ffbit)) {
  443. set_bit(FF_PERIODIC, dev->ffbit);
  444. set_bit(FF_SINE, dev->ffbit);
  445. set_bit(FF_TRIANGLE, dev->ffbit);
  446. set_bit(FF_SQUARE, dev->ffbit);
  447. }
  448. for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
  449. ml->states[i].effect = &ff->effects[i];
  450. return 0;
  451. }
  452. EXPORT_SYMBOL_GPL(input_ff_create_memless);