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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 debug(format, arg...) pr_debug("ff-memless: " format "\n", ## arg)
  27
  28 #include <linux/input.h>
  29 #include <linux/module.h>
  30 #include <linux/mutex.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/jiffies.h>
  33
  34 #include "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         debug("calculating next timer");
 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                 debug("no actions");
 152                 del_timer(&ml->timer);
 153         } else {
 154                 debug("timer set");
 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                 debug("value = 0x%x, attack_level = 0x%x", value,
 176                       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         debug("difference = %d", difference);
 194         debug("time_from_level = 0x%x", time_from_level);
 195         debug("time_of_envelope = 0x%x", time_of_envelope);
 196
 197         difference = difference * time_from_level / time_of_envelope;
 198
 199         debug("difference = %d", 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         printk(KERN_ERR
 218                "ff-memless: invalid type in get_compatible_type()\n");
 219
 220         return 0;
 221 }
 222
 223 /*
 224  * Combine two effects and apply gain.
 225  */
 226 static void ml_combine_effects(struct ff_effect *effect,
 227                                struct ml_effect_state *state,
 228                                unsigned int gain)
 229 {
 230         struct ff_effect *new = state->effect;
 231         unsigned int strong, weak, i;
 232         int x, y;
 233         fixp_t level;
 234
 235         switch (new->type) {
 236         case FF_CONSTANT:
 237                 i = new->direction * 360 / 0xffff;
 238                 level = fixp_new16(apply_envelope(state,
 239                                         new->u.constant.level,
 240                                         &new->u.constant.envelope));
 241                 x = fixp_mult(fixp_sin(i), level) * gain / 0xffff;
 242                 y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff;
 243                 /*
 244                  * here we abuse ff_ramp to hold x and y of constant force
 245                  * If in future any driver wants something else than x and y
 246                  * in s8, this should be changed to something more generic
 247                  */
 248                 effect->u.ramp.start_level =
 249                         clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
 250                 effect->u.ramp.end_level =
 251                         clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
 252                 break;
 253
 254         case FF_RUMBLE:
 255                 strong = new->u.rumble.strong_magnitude * gain / 0xffff;
 256                 weak = new->u.rumble.weak_magnitude * gain / 0xffff;
 257                 effect->u.rumble.strong_magnitude =
 258                         min(strong + effect->u.rumble.strong_magnitude,
 259                             0xffffU);
 260                 effect->u.rumble.weak_magnitude =
 261                         min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
 262                 break;
 263
 264         case FF_PERIODIC:
 265                 i = apply_envelope(state, abs(new->u.periodic.magnitude),
 266                                    &new->u.periodic.envelope);
 267
 268                 /* here we also scale it 0x7fff => 0xffff */
 269                 i = i * gain / 0x7fff;
 270
 271                 effect->u.rumble.strong_magnitude =
 272                         min(i + effect->u.rumble.strong_magnitude, 0xffffU);
 273                 effect->u.rumble.weak_magnitude =
 274                         min(i + effect->u.rumble.weak_magnitude, 0xffffU);
 275                 break;
 276
 277         default:
 278                 printk(KERN_ERR "ff-memless: invalid type in ml_combine_effects()\n");
 279                 break;
 280         }
 281
 282 }
 283
 284
 285 /*
 286  * Because memoryless devices have only one effect per effect type active
 287  * at one time we have to combine multiple effects into one
 288  */
 289 static int ml_get_combo_effect(struct ml_device *ml,
 290                                unsigned long *effect_handled,
 291                                struct ff_effect *combo_effect)
 292 {
 293         struct ff_effect *effect;
 294         struct ml_effect_state *state;
 295         int effect_type;
 296         int i;
 297
 298         memset(combo_effect, 0, sizeof(struct ff_effect));
 299
 300         for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
 301                 if (__test_and_set_bit(i, effect_handled))
 302                         continue;
 303
 304                 state = &ml->states[i];
 305                 effect = state->effect;
 306
 307                 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
 308                         continue;
 309
 310                 if (time_before(jiffies, state->play_at))
 311                         continue;
 312
 313                 /*
 314                  * here we have started effects that are either
 315                  * currently playing (and may need be aborted)
 316                  * or need to start playing.
 317                  */
 318                 effect_type = get_compatible_type(ml->dev->ff, effect->type);
 319                 if (combo_effect->type != effect_type) {
 320                         if (combo_effect->type != 0) {
 321                                 __clear_bit(i, effect_handled);
 322                                 continue;
 323                         }
 324                         combo_effect->type = effect_type;
 325                 }
 326
 327                 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
 328                         __clear_bit(FF_EFFECT_PLAYING, &state->flags);
 329                         __clear_bit(FF_EFFECT_STARTED, &state->flags);
 330                 } else if (effect->replay.length &&
 331                            time_after_eq(jiffies, state->stop_at)) {
 332
 333                         __clear_bit(FF_EFFECT_PLAYING, &state->flags);
 334
 335                         if (--state->count <= 0) {
 336                                 __clear_bit(FF_EFFECT_STARTED, &state->flags);
 337                         } else {
 338                                 state->play_at = jiffies +
 339                                         msecs_to_jiffies(effect->replay.delay);
 340                                 state->stop_at = state->play_at +
 341                                         msecs_to_jiffies(effect->replay.length);
 342                         }
 343                 } else {
 344                         __set_bit(FF_EFFECT_PLAYING, &state->flags);
 345                         state->adj_at = jiffies;
 346                         ml_combine_effects(combo_effect, state, ml->gain);
 347                 }
 348         }
 349
 350         return combo_effect->type != 0;
 351 }
 352
 353 static void ml_play_effects(struct ml_device *ml)
 354 {
 355         struct ff_effect effect;
 356         DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
 357
 358         memset(handled_bm, 0, sizeof(handled_bm));
 359
 360         while (ml_get_combo_effect(ml, handled_bm, &effect))
 361                 ml->play_effect(ml->dev, ml->private, &effect);
 362
 363         ml_schedule_timer(ml);
 364 }
 365
 366 static void ml_effect_timer(unsigned long timer_data)
 367 {
 368         struct input_dev *dev = (struct input_dev *)timer_data;
 369         struct ml_device *ml = dev->ff->private;
 370         unsigned long flags;
 371
 372         debug("timer: updating effects");
 373
 374         spin_lock_irqsave(&dev->event_lock, flags);
 375         ml_play_effects(ml);
 376         spin_unlock_irqrestore(&dev->event_lock, flags);
 377 }
 378
 379 /*
 380  * Sets requested gain for FF effects. Called with dev->event_lock held.
 381  */
 382 static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
 383 {
 384         struct ml_device *ml = dev->ff->private;
 385         int i;
 386
 387         ml->gain = gain;
 388
 389         for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
 390                 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
 391
 392         ml_play_effects(ml);
 393 }
 394
 395 /*
 396  * Start/stop specified FF effect. Called with dev->event_lock held.
 397  */
 398 static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
 399 {
 400         struct ml_device *ml = dev->ff->private;
 401         struct ml_effect_state *state = &ml->states[effect_id];
 402
 403         if (value > 0) {
 404                 debug("initiated play");
 405
 406                 __set_bit(FF_EFFECT_STARTED, &state->flags);
 407                 state->count = value;
 408                 state->play_at = jiffies +
 409                                  msecs_to_jiffies(state->effect->replay.delay);
 410                 state->stop_at = state->play_at +
 411                                  msecs_to_jiffies(state->effect->replay.length);
 412                 state->adj_at = state->play_at;
 413
 414                 ml_schedule_timer(ml);
 415
 416         } else {
 417                 debug("initiated stop");
 418
 419                 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
 420                         __set_bit(FF_EFFECT_ABORTING, &state->flags);
 421                 else
 422                         __clear_bit(FF_EFFECT_STARTED, &state->flags);
 423
 424                 ml_play_effects(ml);
 425         }
 426
 427         return 0;
 428 }
 429
 430 static int ml_ff_upload(struct input_dev *dev,
 431                         struct ff_effect *effect, struct ff_effect *old)
 432 {
 433         struct ml_device *ml = dev->ff->private;
 434         struct ml_effect_state *state = &ml->states[effect->id];
 435
 436         spin_lock_irq(&dev->event_lock);
 437
 438         if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
 439                 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
 440                 state->play_at = jiffies +
 441                                  msecs_to_jiffies(state->effect->replay.delay);
 442                 state->stop_at = state->play_at +
 443                                  msecs_to_jiffies(state->effect->replay.length);
 444                 state->adj_at = state->play_at;
 445                 ml_schedule_timer(ml);
 446         }
 447
 448         spin_unlock_irq(&dev->event_lock);
 449
 450         return 0;
 451 }
 452
 453 static void ml_ff_destroy(struct ff_device *ff)
 454 {
 455         struct ml_device *ml = ff->private;
 456
 457         kfree(ml->private);
 458 }
 459
 460 /**
 461  * input_ff_create_memless() - create memoryless force-feedback device
 462  * @dev: input device supporting force-feedback
 463  * @data: driver-specific data to be passed into @play_effect
 464  * @play_effect: driver-specific method for playing FF effect
 465  */
 466 int input_ff_create_memless(struct input_dev *dev, void *data,
 467                 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
 468 {
 469         struct ml_device *ml;
 470         struct ff_device *ff;
 471         int error;
 472         int i;
 473
 474         ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
 475         if (!ml)
 476                 return -ENOMEM;
 477
 478         ml->dev = dev;
 479         ml->private = data;
 480         ml->play_effect = play_effect;
 481         ml->gain = 0xffff;
 482         setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
 483
 484         set_bit(FF_GAIN, dev->ffbit);
 485
 486         error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
 487         if (error) {
 488                 kfree(ml);
 489                 return error;
 490         }
 491
 492         ff = dev->ff;
 493         ff->private = ml;
 494         ff->upload = ml_ff_upload;
 495         ff->playback = ml_ff_playback;
 496         ff->set_gain = ml_ff_set_gain;
 497         ff->destroy = ml_ff_destroy;
 498
 499         /* we can emulate periodic effects with RUMBLE */
 500         if (test_bit(FF_RUMBLE, ff->ffbit)) {
 501                 set_bit(FF_PERIODIC, dev->ffbit);
 502                 set_bit(FF_SINE, dev->ffbit);
 503                 set_bit(FF_TRIANGLE, dev->ffbit);
 504                 set_bit(FF_SQUARE, dev->ffbit);
 505         }
 506
 507         for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
 508                 ml->states[i].effect = &ff->effects[i];
 509
 510         return 0;
 511 }
 512 EXPORT_SYMBOL_GPL(input_ff_create_memless);