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 debug(format, arg...) pr_debug("ff-memless: " format "\n", ## arg) 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 35#include "fixp-arith.h" 36 37MODULE_LICENSE("GPL"); 38MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>"); 39MODULE_DESCRIPTION("Force feedback support for memoryless devices"); 40 41/* Number of effects handled with memoryless devices */ 42#define FF_MEMLESS_EFFECTS 16 43 44/* Envelope update interval in ms */ 45#define FF_ENVELOPE_INTERVAL 50 46 47#define FF_EFFECT_STARTED 0 48#define FF_EFFECT_PLAYING 1 49#define FF_EFFECT_ABORTING 2 50 51struct ml_effect_state { 52 struct ff_effect *effect; 53 unsigned long flags; /* effect state (STARTED, PLAYING, etc) */ 54 int count; /* loop count of the effect */ 55 unsigned long play_at; /* start time */ 56 unsigned long stop_at; /* stop time */ 57 unsigned long adj_at; /* last time the effect was sent */ 58}; 59 60struct ml_device { 61 void *private; 62 struct ml_effect_state states[FF_MEMLESS_EFFECTS]; 63 int gain; 64 struct timer_list timer; 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 * Only left/right direction should be used (under/over 0x8000) for 226 * forward/reverse motor direction (to keep calculation fast & simple). 227 */ 228static 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 */ 243static 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 printk(KERN_ERR "ff-memless: 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 */ 326static 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 390static 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 403static 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 debug("timer: updating effects"); 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 */ 419static 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 */ 435static 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 debug("initiated play"); 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 debug("initiated stop"); 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 465static 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 488static 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 */ 501int 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} 547EXPORT_SYMBOL_GPL(input_ff_create_memless); 548