drivers/input/ff-core.c

   1 /*
   2  *  Force feedback support for Linux input subsystem
   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-core: " format "\n", ## arg)
  27
  28 #include <linux/input.h>
  29 #include <linux/module.h>
  30 #include <linux/mutex.h>
  31
  32 /*
  33  * Check that the effect_id is a valid effect and whether the user
  34  * is the owner
  35  */
  36 static int check_effect_access(struct ff_device *ff, int effect_id,
  37                                 struct file *file)
  38 {
  39         if (effect_id < 0 || effect_id >= ff->max_effects ||
  40             !ff->effect_owners[effect_id])
  41                 return -EINVAL;
  42
  43         if (file && ff->effect_owners[effect_id] != file)
  44                 return -EACCES;
  45
  46         return 0;
  47 }
  48
  49 /*
  50  * Checks whether 2 effects can be combined together
  51  */
  52 static inline int check_effects_compatible(struct ff_effect *e1,
  53                                            struct ff_effect *e2)
  54 {
  55         return e1->type == e2->type &&
  56                (e1->type != FF_PERIODIC ||
  57                 e1->u.periodic.waveform == e2->u.periodic.waveform);
  58 }
  59
  60 /*
  61  * Convert an effect into compatible one
  62  */
  63 static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
  64 {
  65         int magnitude;
  66
  67         switch (effect->type) {
  68         case FF_RUMBLE:
  69                 if (!test_bit(FF_PERIODIC, ff->ffbit))
  70                         return -EINVAL;
  71
  72                 /*
  73                  * calculate manginude of sine wave as average of rumble's
  74                  * 2/3 of strong magnitude and 1/3 of weak magnitude
  75                  */
  76                 magnitude = effect->u.rumble.strong_magnitude / 3 +
  77                             effect->u.rumble.weak_magnitude / 6;
  78
  79                 effect->type = FF_PERIODIC;
  80                 effect->u.periodic.waveform = FF_SINE;
  81                 effect->u.periodic.period = 50;
  82                 effect->u.periodic.magnitude = max(magnitude, 0x7fff);
  83                 effect->u.periodic.offset = 0;
  84                 effect->u.periodic.phase = 0;
  85                 effect->u.periodic.envelope.attack_length = 0;
  86                 effect->u.periodic.envelope.attack_level = 0;
  87                 effect->u.periodic.envelope.fade_length = 0;
  88                 effect->u.periodic.envelope.fade_level = 0;
  89
  90                 return 0;
  91
  92         default:
  93                 /* Let driver handle conversion */
  94                 return 0;
  95         }
  96 }
  97
  98 /**
  99  * input_ff_upload() - upload effect into force-feedback device
 100  * @dev: input device
 101  * @effect: effect to be uploaded
 102  * @file: owner of the effect
 103  */
 104 int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
 105                     struct file *file)
 106 {
 107         struct ff_device *ff = dev->ff;
 108         struct ff_effect *old;
 109         int ret = 0;
 110         int id;
 111
 112         if (!test_bit(EV_FF, dev->evbit))
 113                 return -ENOSYS;
 114
 115         if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
 116             !test_bit(effect->type, dev->ffbit)) {
 117                 debug("invalid or not supported effect type in upload");
 118                 return -EINVAL;
 119         }
 120
 121         if (effect->type == FF_PERIODIC &&
 122             (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
 123              effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
 124              !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
 125                 debug("invalid or not supported wave form in upload");
 126                 return -EINVAL;
 127         }
 128
 129         if (!test_bit(effect->type, ff->ffbit)) {
 130                 ret = compat_effect(ff, effect);
 131                 if (ret)
 132                         return ret;
 133         }
 134
 135         mutex_lock(&ff->mutex);
 136
 137         if (effect->id == -1) {
 138                 for (id = 0; id < ff->max_effects; id++)
 139                      if (!ff->effect_owners[id])
 140                         break;
 141
 142                 if (id >= ff->max_effects) {
 143                         ret = -ENOSPC;
 144                         goto out;
 145                 }
 146
 147                 effect->id = id;
 148                 old = NULL;
 149
 150         } else {
 151                 id = effect->id;
 152
 153                 ret = check_effect_access(ff, id, file);
 154                 if (ret)
 155                         goto out;
 156
 157                 old = &ff->effects[id];
 158
 159                 if (!check_effects_compatible(effect, old)) {
 160                         ret = -EINVAL;
 161                         goto out;
 162                 }
 163         }
 164
 165         ret = ff->upload(dev, effect, old);
 166         if (ret)
 167                 goto out;
 168
 169         ff->effects[id] = *effect;
 170         ff->effect_owners[id] = file;
 171
 172  out:
 173         mutex_unlock(&ff->mutex);
 174         return ret;
 175 }
 176 EXPORT_SYMBOL_GPL(input_ff_upload);
 177
 178 /*
 179  * Erases the effect if the requester is also the effect owner. The mutex
 180  * should already be locked before calling this function.
 181  */
 182 static int erase_effect(struct input_dev *dev, int effect_id,
 183                         struct file *file)
 184 {
 185         struct ff_device *ff = dev->ff;
 186         int error;
 187
 188         error = check_effect_access(ff, effect_id, file);
 189         if (error)
 190                 return error;
 191
 192         ff->playback(dev, effect_id, 0);
 193
 194         if (ff->erase) {
 195                 error = ff->erase(dev, effect_id);
 196                 if (error)
 197                         return error;
 198         }
 199
 200         ff->effect_owners[effect_id] = NULL;
 201
 202         return 0;
 203 }
 204
 205 /**
 206  * input_ff_erase - erase a force-feedback effect from device
 207  * @dev: input device to erase effect from
 208  * @effect_id: id of the ffect to be erased
 209  * @file: purported owner of the request
 210  *
 211  * This function erases a force-feedback effect from specified device.
 212  * The effect will only be erased if it was uploaded through the same
 213  * file handle that is requesting erase.
 214  */
 215 int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
 216 {
 217         struct ff_device *ff = dev->ff;
 218         int ret;
 219
 220         if (!test_bit(EV_FF, dev->evbit))
 221                 return -ENOSYS;
 222
 223         mutex_lock(&ff->mutex);
 224         ret = erase_effect(dev, effect_id, file);
 225         mutex_unlock(&ff->mutex);
 226
 227         return ret;
 228 }
 229 EXPORT_SYMBOL_GPL(input_ff_erase);
 230
 231 /*
 232  * flush_effects - erase all effects owned by a file handle
 233  */
 234 static int flush_effects(struct input_dev *dev, struct file *file)
 235 {
 236         struct ff_device *ff = dev->ff;
 237         int i;
 238
 239         debug("flushing now");
 240
 241         mutex_lock(&ff->mutex);
 242
 243         for (i = 0; i < ff->max_effects; i++)
 244                 erase_effect(dev, i, file);
 245
 246         mutex_unlock(&ff->mutex);
 247
 248         return 0;
 249 }
 250
 251 /**
 252  * input_ff_event() - generic handler for force-feedback events
 253  * @dev: input device to send the effect to
 254  * @type: event type (anything but EV_FF is ignored)
 255  * @code: event code
 256  * @value: event value
 257  */
 258 int input_ff_event(struct input_dev *dev, unsigned int type,
 259                    unsigned int code, int value)
 260 {
 261         struct ff_device *ff = dev->ff;
 262
 263         if (type != EV_FF)
 264                 return 0;
 265
 266         mutex_lock(&ff->mutex);
 267
 268         switch (code) {
 269         case FF_GAIN:
 270                 if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff)
 271                         break;
 272
 273                 ff->set_gain(dev, value);
 274                 break;
 275
 276         case FF_AUTOCENTER:
 277                 if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffff)
 278                         break;
 279
 280                 ff->set_autocenter(dev, value);
 281                 break;
 282
 283         default:
 284                 if (check_effect_access(ff, code, NULL) == 0)
 285                         ff->playback(dev, code, value);
 286                 break;
 287         }
 288
 289         mutex_unlock(&ff->mutex);
 290         return 0;
 291 }
 292 EXPORT_SYMBOL_GPL(input_ff_event);
 293
 294 /**
 295  * input_ff_create() - create force-feedback device
 296  * @dev: input device supporting force-feedback
 297  * @max_effects: maximum number of effects supported by the device
 298  *
 299  * This function allocates all necessary memory for a force feedback
 300  * portion of an input device and installs all default handlers.
 301  * @dev->ffbit should be already set up before calling this function.
 302  * Once ff device is created you need to setup its upload, erase,
 303  * playback and other handlers before registering input device
 304  */
 305 int input_ff_create(struct input_dev *dev, int max_effects)
 306 {
 307         struct ff_device *ff;
 308         int i;
 309
 310         if (!max_effects) {
 311                 printk(KERN_ERR
 312                        "ff-core: cannot allocate device without any effects\n");
 313                 return -EINVAL;
 314         }
 315
 316         ff = kzalloc(sizeof(struct ff_device) +
 317                      max_effects * sizeof(struct file *), GFP_KERNEL);
 318         if (!ff)
 319                 return -ENOMEM;
 320
 321         ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
 322                               GFP_KERNEL);
 323         if (!ff->effects) {
 324                 kfree(ff);
 325                 return -ENOMEM;
 326         }
 327
 328         ff->max_effects = max_effects;
 329         mutex_init(&ff->mutex);
 330
 331         dev->ff = ff;
 332         dev->flush = flush_effects;
 333         dev->event = input_ff_event;
 334         set_bit(EV_FF, dev->evbit);
 335
 336         /* Copy "true" bits into ff device bitmap */
 337         for (i = 0; i <= FF_MAX; i++)
 338                 if (test_bit(i, dev->ffbit))
 339                         set_bit(i, ff->ffbit);
 340
 341         /* we can emulate RUMBLE with periodic effects */
 342         if (test_bit(FF_PERIODIC, ff->ffbit))
 343                 set_bit(FF_RUMBLE, dev->ffbit);
 344
 345         return 0;
 346 }
 347 EXPORT_SYMBOL_GPL(input_ff_create);
 348
 349 /**
 350  * input_ff_free() - frees force feedback portion of input device
 351  * @dev: input device supporting force feedback
 352  *
 353  * This function is only needed in error path as input core will
 354  * automatically free force feedback structures when device is
 355  * destroyed.
 356  */
 357 void input_ff_destroy(struct input_dev *dev)
 358 {
 359         clear_bit(EV_FF, dev->evbit);
 360         if (dev->ff) {
 361                 if (dev->ff->destroy)
 362                         dev->ff->destroy(dev->ff);
 363                 kfree(dev->ff->private);
 364                 kfree(dev->ff);
 365                 dev->ff = NULL;
 366         }
 367 }
 368 EXPORT_SYMBOL_GPL(input_ff_destroy);