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 case FF_CONSTANT: 78 return &effect->u.constant.envelope; 79 default: 80 return &empty_envelope; 81 } 82 } 83 84 /* 85 * Check for the next time envelope requires an update on memoryless devices 86 */ 87 static unsigned long calculate_next_time(struct ml_effect_state *state) 88 { 89 const struct ff_envelope *envelope = get_envelope(state->effect); 90 unsigned long attack_stop, fade_start, next_fade; 91 92 if (envelope->attack_length) { 93 attack_stop = state->play_at + 94 msecs_to_jiffies(envelope->attack_length); 95 if (time_before(state->adj_at, attack_stop)) 96 return state->adj_at + 97 msecs_to_jiffies(FF_ENVELOPE_INTERVAL); 98 } 99 100 if (state->effect->replay.length) { 101 if (envelope->fade_length) { 102 /* check when fading should start */ 103 fade_start = state->stop_at - 104 msecs_to_jiffies(envelope->fade_length); 105 106 if (time_before(state->adj_at, fade_start)) 107 return fade_start; 108 109 /* already fading, advance to next checkpoint */ 110 next_fade = state->adj_at + 111 msecs_to_jiffies(FF_ENVELOPE_INTERVAL); 112 if (time_before(next_fade, state->stop_at)) 113 return next_fade; 114 } 115 116 return state->stop_at; 117 } 118 119 return state->play_at; 120 } 121 122 static void ml_schedule_timer(struct ml_device *ml) 123 { 124 struct ml_effect_state *state; 125 unsigned long now = jiffies; 126 unsigned long earliest = 0; 127 unsigned long next_at; 128 int events = 0; 129 int i; 130 131 pr_debug("calculating next timer\n"); 132 133 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { 134 135 state = &ml->states[i]; 136 137 if (!test_bit(FF_EFFECT_STARTED, &state->flags)) 138 continue; 139 140 if (test_bit(FF_EFFECT_PLAYING, &state->flags)) 141 next_at = calculate_next_time(state); 142 else 143 next_at = state->play_at; 144 145 if (time_before_eq(now, next_at) && 146 (++events == 1 || time_before(next_at, earliest))) 147 earliest = next_at; 148 } 149 150 if (!events) { 151 pr_debug("no actions\n"); 152 del_timer(&ml->timer); 153 } else { 154 pr_debug("timer set\n"); 155 mod_timer(&ml->timer, earliest); 156 } 157 } 158 159 /* 160 * Apply an envelope to a value 161 */ 162 static int apply_envelope(struct ml_effect_state *state, int value, 163 struct ff_envelope *envelope) 164 { 165 struct ff_effect *effect = state->effect; 166 unsigned long now = jiffies; 167 int time_from_level; 168 int time_of_envelope; 169 int envelope_level; 170 int difference; 171 172 if (envelope->attack_length && 173 time_before(now, 174 state->play_at + msecs_to_jiffies(envelope->attack_length))) { 175 pr_debug("value = 0x%x, attack_level = 0x%x\n", 176 value, envelope->attack_level); 177 time_from_level = jiffies_to_msecs(now - state->play_at); 178 time_of_envelope = envelope->attack_length; 179 envelope_level = min_t(__s16, envelope->attack_level, 0x7fff); 180 181 } else if (envelope->fade_length && effect->replay.length && 182 time_after(now, 183 state->stop_at - msecs_to_jiffies(envelope->fade_length)) && 184 time_before(now, state->stop_at)) { 185 time_from_level = jiffies_to_msecs(state->stop_at - now); 186 time_of_envelope = envelope->fade_length; 187 envelope_level = min_t(__s16, envelope->fade_level, 0x7fff); 188 } else 189 return value; 190 191 difference = abs(value) - envelope_level; 192 193 pr_debug("difference = %d\n", difference); 194 pr_debug("time_from_level = 0x%x\n", time_from_level); 195 pr_debug("time_of_envelope = 0x%x\n", time_of_envelope); 196 197 difference = difference * time_from_level / time_of_envelope; 198 199 pr_debug("difference = %d\n", difference); 200 201 return value < 0 ? 202 -(difference + envelope_level) : (difference + envelope_level); 203 } 204 205 /* 206 * Return the type the effect has to be converted into (memless devices) 207 */ 208 static int get_compatible_type(struct ff_device *ff, int effect_type) 209 { 210 211 if (test_bit(effect_type, ff->ffbit)) 212 return effect_type; 213 214 if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit)) 215 return FF_RUMBLE; 216 217 pr_err("invalid type in get_compatible_type()\n"); 218 219 return 0; 220 } 221 222 /* 223 * Only left/right direction should be used (under/over 0x8000) for 224 * forward/reverse motor direction (to keep calculation fast & simple). 225 */ 226 static u16 ml_calculate_direction(u16 direction, u16 force, 227 u16 new_direction, u16 new_force) 228 { 229 if (!force) 230 return new_direction; 231 if (!new_force) 232 return direction; 233 return (((u32)(direction >> 1) * force + 234 (new_direction >> 1) * new_force) / 235 (force + new_force)) << 1; 236 } 237 238 /* 239 * Combine two effects and apply gain. 240 */ 241 static void ml_combine_effects(struct ff_effect *effect, 242 struct ml_effect_state *state, 243 int gain) 244 { 245 struct ff_effect *new = state->effect; 246 unsigned int strong, weak, i; 247 int x, y; 248 fixp_t level; 249 250 switch (new->type) { 251 case FF_CONSTANT: 252 i = new->direction * 360 / 0xffff; 253 level = fixp_new16(apply_envelope(state, 254 new->u.constant.level, 255 &new->u.constant.envelope)); 256 x = fixp_mult(fixp_sin(i), level) * gain / 0xffff; 257 y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff; 258 /* 259 * here we abuse ff_ramp to hold x and y of constant force 260 * If in future any driver wants something else than x and y 261 * in s8, this should be changed to something more generic 262 */ 263 effect->u.ramp.start_level = 264 clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f); 265 effect->u.ramp.end_level = 266 clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f); 267 break; 268 269 case FF_RUMBLE: 270 strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff; 271 weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff; 272 273 if (effect->u.rumble.strong_magnitude + strong) 274 effect->direction = ml_calculate_direction( 275 effect->direction, 276 effect->u.rumble.strong_magnitude, 277 new->direction, strong); 278 else if (effect->u.rumble.weak_magnitude + weak) 279 effect->direction = ml_calculate_direction( 280 effect->direction, 281 effect->u.rumble.weak_magnitude, 282 new->direction, weak); 283 else 284 effect->direction = 0; 285 effect->u.rumble.strong_magnitude = 286 min(strong + effect->u.rumble.strong_magnitude, 287 0xffffU); 288 effect->u.rumble.weak_magnitude = 289 min(weak + effect->u.rumble.weak_magnitude, 0xffffU); 290 break; 291 292 case FF_PERIODIC: 293 i = apply_envelope(state, abs(new->u.periodic.magnitude), 294 &new->u.periodic.envelope); 295 296 /* here we also scale it 0x7fff => 0xffff */ 297 i = i * gain / 0x7fff; 298 299 if (effect->u.rumble.strong_magnitude + i) 300 effect->direction = ml_calculate_direction( 301 effect->direction, 302 effect->u.rumble.strong_magnitude, 303 new->direction, i); 304 else 305 effect->direction = 0; 306 effect->u.rumble.strong_magnitude = 307 min(i + effect->u.rumble.strong_magnitude, 0xffffU); 308 effect->u.rumble.weak_magnitude = 309 min(i + effect->u.rumble.weak_magnitude, 0xffffU); 310 break; 311 312 default: 313 pr_err("invalid type in ml_combine_effects()\n"); 314 break; 315 } 316 317 } 318 319 320 /* 321 * Because memoryless devices have only one effect per effect type active 322 * at one time we have to combine multiple effects into one 323 */ 324 static int ml_get_combo_effect(struct ml_device *ml, 325 unsigned long *effect_handled, 326 struct ff_effect *combo_effect) 327 { 328 struct ff_effect *effect; 329 struct ml_effect_state *state; 330 int effect_type; 331 int i; 332 333 memset(combo_effect, 0, sizeof(struct ff_effect)); 334 335 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { 336 if (__test_and_set_bit(i, effect_handled)) 337 continue; 338 339 state = &ml->states[i]; 340 effect = state->effect; 341 342 if (!test_bit(FF_EFFECT_STARTED, &state->flags)) 343 continue; 344 345 if (time_before(jiffies, state->play_at)) 346 continue; 347 348 /* 349 * here we have started effects that are either 350 * currently playing (and may need be aborted) 351 * or need to start playing. 352 */ 353 effect_type = get_compatible_type(ml->dev->ff, effect->type); 354 if (combo_effect->type != effect_type) { 355 if (combo_effect->type != 0) { 356 __clear_bit(i, effect_handled); 357 continue; 358 } 359 combo_effect->type = effect_type; 360 } 361 362 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) { 363 __clear_bit(FF_EFFECT_PLAYING, &state->flags); 364 __clear_bit(FF_EFFECT_STARTED, &state->flags); 365 } else if (effect->replay.length && 366 time_after_eq(jiffies, state->stop_at)) { 367 368 __clear_bit(FF_EFFECT_PLAYING, &state->flags); 369 370 if (--state->count <= 0) { 371 __clear_bit(FF_EFFECT_STARTED, &state->flags); 372 } else { 373 state->play_at = jiffies + 374 msecs_to_jiffies(effect->replay.delay); 375 state->stop_at = state->play_at + 376 msecs_to_jiffies(effect->replay.length); 377 } 378 } else { 379 __set_bit(FF_EFFECT_PLAYING, &state->flags); 380 state->adj_at = jiffies; 381 ml_combine_effects(combo_effect, state, ml->gain); 382 } 383 } 384 385 return combo_effect->type != 0; 386 } 387 388 static void ml_play_effects(struct ml_device *ml) 389 { 390 struct ff_effect effect; 391 DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS); 392 393 memset(handled_bm, 0, sizeof(handled_bm)); 394 395 while (ml_get_combo_effect(ml, handled_bm, &effect)) 396 ml->play_effect(ml->dev, ml->private, &effect); 397 398 ml_schedule_timer(ml); 399 } 400 401 static void ml_effect_timer(unsigned long timer_data) 402 { 403 struct input_dev *dev = (struct input_dev *)timer_data; 404 struct ml_device *ml = dev->ff->private; 405 unsigned long flags; 406 407 pr_debug("timer: updating effects\n"); 408 409 spin_lock_irqsave(&dev->event_lock, flags); 410 ml_play_effects(ml); 411 spin_unlock_irqrestore(&dev->event_lock, flags); 412 } 413 414 /* 415 * Sets requested gain for FF effects. Called with dev->event_lock held. 416 */ 417 static void ml_ff_set_gain(struct input_dev *dev, u16 gain) 418 { 419 struct ml_device *ml = dev->ff->private; 420 int i; 421 422 ml->gain = gain; 423 424 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) 425 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags); 426 427 ml_play_effects(ml); 428 } 429 430 /* 431 * Start/stop specified FF effect. Called with dev->event_lock held. 432 */ 433 static int ml_ff_playback(struct input_dev *dev, int effect_id, int value) 434 { 435 struct ml_device *ml = dev->ff->private; 436 struct ml_effect_state *state = &ml->states[effect_id]; 437 438 if (value > 0) { 439 pr_debug("initiated play\n"); 440 441 __set_bit(FF_EFFECT_STARTED, &state->flags); 442 state->count = value; 443 state->play_at = jiffies + 444 msecs_to_jiffies(state->effect->replay.delay); 445 state->stop_at = state->play_at + 446 msecs_to_jiffies(state->effect->replay.length); 447 state->adj_at = state->play_at; 448 449 } else { 450 pr_debug("initiated stop\n"); 451 452 if (test_bit(FF_EFFECT_PLAYING, &state->flags)) 453 __set_bit(FF_EFFECT_ABORTING, &state->flags); 454 else 455 __clear_bit(FF_EFFECT_STARTED, &state->flags); 456 } 457 458 ml_play_effects(ml); 459 460 return 0; 461 } 462 463 static int ml_ff_upload(struct input_dev *dev, 464 struct ff_effect *effect, struct ff_effect *old) 465 { 466 struct ml_device *ml = dev->ff->private; 467 struct ml_effect_state *state = &ml->states[effect->id]; 468 469 spin_lock_irq(&dev->event_lock); 470 471 if (test_bit(FF_EFFECT_STARTED, &state->flags)) { 472 __clear_bit(FF_EFFECT_PLAYING, &state->flags); 473 state->play_at = jiffies + 474 msecs_to_jiffies(state->effect->replay.delay); 475 state->stop_at = state->play_at + 476 msecs_to_jiffies(state->effect->replay.length); 477 state->adj_at = state->play_at; 478 ml_schedule_timer(ml); 479 } 480 481 spin_unlock_irq(&dev->event_lock); 482 483 return 0; 484 } 485 486 static void ml_ff_destroy(struct ff_device *ff) 487 { 488 struct ml_device *ml = ff->private; 489 490 kfree(ml->private); 491 } 492 493 /** 494 * input_ff_create_memless() - create memoryless force-feedback device 495 * @dev: input device supporting force-feedback 496 * @data: driver-specific data to be passed into @play_effect 497 * @play_effect: driver-specific method for playing FF effect 498 */ 499 int input_ff_create_memless(struct input_dev *dev, void *data, 500 int (*play_effect)(struct input_dev *, void *, struct ff_effect *)) 501 { 502 struct ml_device *ml; 503 struct ff_device *ff; 504 int error; 505 int i; 506 507 ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL); 508 if (!ml) 509 return -ENOMEM; 510 511 ml->dev = dev; 512 ml->private = data; 513 ml->play_effect = play_effect; 514 ml->gain = 0xffff; 515 setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev); 516 517 set_bit(FF_GAIN, dev->ffbit); 518 519 error = input_ff_create(dev, FF_MEMLESS_EFFECTS); 520 if (error) { 521 kfree(ml); 522 return error; 523 } 524 525 ff = dev->ff; 526 ff->private = ml; 527 ff->upload = ml_ff_upload; 528 ff->playback = ml_ff_playback; 529 ff->set_gain = ml_ff_set_gain; 530 ff->destroy = ml_ff_destroy; 531 532 /* we can emulate periodic effects with RUMBLE */ 533 if (test_bit(FF_RUMBLE, ff->ffbit)) { 534 set_bit(FF_PERIODIC, dev->ffbit); 535 set_bit(FF_SINE, dev->ffbit); 536 set_bit(FF_TRIANGLE, dev->ffbit); 537 set_bit(FF_SQUARE, dev->ffbit); 538 } 539 540 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) 541 ml->states[i].effect = &ff->effects[i]; 542 543 return 0; 544 } 545 EXPORT_SYMBOL_GPL(input_ff_create_memless); 546