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 #include <linux/input.h> 27 #include <linux/module.h> 28 #include <linux/mutex.h> 29 #include <linux/sched.h> 30 #include <linux/slab.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 magnitude 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 dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n"); 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 dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n"); 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 spin_lock_irq(&dev->event_lock); 170 ff->effects[id] = *effect; 171 ff->effect_owners[id] = file; 172 spin_unlock_irq(&dev->event_lock); 173 174 out: 175 mutex_unlock(&ff->mutex); 176 return ret; 177 } 178 EXPORT_SYMBOL_GPL(input_ff_upload); 179 180 /* 181 * Erases the effect if the requester is also the effect owner. The mutex 182 * should already be locked before calling this function. 183 */ 184 static int erase_effect(struct input_dev *dev, int effect_id, 185 struct file *file) 186 { 187 struct ff_device *ff = dev->ff; 188 int error; 189 190 error = check_effect_access(ff, effect_id, file); 191 if (error) 192 return error; 193 194 spin_lock_irq(&dev->event_lock); 195 ff->playback(dev, effect_id, 0); 196 ff->effect_owners[effect_id] = NULL; 197 spin_unlock_irq(&dev->event_lock); 198 199 if (ff->erase) { 200 error = ff->erase(dev, effect_id); 201 if (error) { 202 spin_lock_irq(&dev->event_lock); 203 ff->effect_owners[effect_id] = file; 204 spin_unlock_irq(&dev->event_lock); 205 206 return error; 207 } 208 } 209 210 return 0; 211 } 212 213 /** 214 * input_ff_erase - erase a force-feedback effect from device 215 * @dev: input device to erase effect from 216 * @effect_id: id of the effect to be erased 217 * @file: purported owner of the request 218 * 219 * This function erases a force-feedback effect from specified device. 220 * The effect will only be erased if it was uploaded through the same 221 * file handle that is requesting erase. 222 */ 223 int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file) 224 { 225 struct ff_device *ff = dev->ff; 226 int ret; 227 228 if (!test_bit(EV_FF, dev->evbit)) 229 return -ENOSYS; 230 231 mutex_lock(&ff->mutex); 232 ret = erase_effect(dev, effect_id, file); 233 mutex_unlock(&ff->mutex); 234 235 return ret; 236 } 237 EXPORT_SYMBOL_GPL(input_ff_erase); 238 239 /* 240 * flush_effects - erase all effects owned by a file handle 241 */ 242 static int flush_effects(struct input_dev *dev, struct file *file) 243 { 244 struct ff_device *ff = dev->ff; 245 int i; 246 247 dev_dbg(&dev->dev, "flushing now\n"); 248 249 mutex_lock(&ff->mutex); 250 251 for (i = 0; i < ff->max_effects; i++) 252 erase_effect(dev, i, file); 253 254 mutex_unlock(&ff->mutex); 255 256 return 0; 257 } 258 259 /** 260 * input_ff_event() - generic handler for force-feedback events 261 * @dev: input device to send the effect to 262 * @type: event type (anything but EV_FF is ignored) 263 * @code: event code 264 * @value: event value 265 */ 266 int input_ff_event(struct input_dev *dev, unsigned int type, 267 unsigned int code, int value) 268 { 269 struct ff_device *ff = dev->ff; 270 271 if (type != EV_FF) 272 return 0; 273 274 switch (code) { 275 case FF_GAIN: 276 if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff) 277 break; 278 279 ff->set_gain(dev, value); 280 break; 281 282 case FF_AUTOCENTER: 283 if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffff) 284 break; 285 286 ff->set_autocenter(dev, value); 287 break; 288 289 default: 290 if (check_effect_access(ff, code, NULL) == 0) 291 ff->playback(dev, code, value); 292 break; 293 } 294 295 return 0; 296 } 297 EXPORT_SYMBOL_GPL(input_ff_event); 298 299 /** 300 * input_ff_create() - create force-feedback device 301 * @dev: input device supporting force-feedback 302 * @max_effects: maximum number of effects supported by the device 303 * 304 * This function allocates all necessary memory for a force feedback 305 * portion of an input device and installs all default handlers. 306 * @dev->ffbit should be already set up before calling this function. 307 * Once ff device is created you need to setup its upload, erase, 308 * playback and other handlers before registering input device 309 */ 310 int input_ff_create(struct input_dev *dev, unsigned int max_effects) 311 { 312 struct ff_device *ff; 313 size_t ff_dev_size; 314 int i; 315 316 if (!max_effects) { 317 dev_err(&dev->dev, "cannot allocate device without any effects\n"); 318 return -EINVAL; 319 } 320 321 ff_dev_size = sizeof(struct ff_device) + 322 max_effects * sizeof(struct file *); 323 if (ff_dev_size < max_effects) /* overflow */ 324 return -EINVAL; 325 326 ff = kzalloc(ff_dev_size, GFP_KERNEL); 327 if (!ff) 328 return -ENOMEM; 329 330 ff->effects = kcalloc(max_effects, sizeof(struct ff_effect), 331 GFP_KERNEL); 332 if (!ff->effects) { 333 kfree(ff); 334 return -ENOMEM; 335 } 336 337 ff->max_effects = max_effects; 338 mutex_init(&ff->mutex); 339 340 dev->ff = ff; 341 dev->flush = flush_effects; 342 dev->event = input_ff_event; 343 __set_bit(EV_FF, dev->evbit); 344 345 /* Copy "true" bits into ff device bitmap */ 346 for_each_set_bit(i, dev->ffbit, FF_CNT) 347 __set_bit(i, ff->ffbit); 348 349 /* we can emulate RUMBLE with periodic effects */ 350 if (test_bit(FF_PERIODIC, ff->ffbit)) 351 __set_bit(FF_RUMBLE, dev->ffbit); 352 353 return 0; 354 } 355 EXPORT_SYMBOL_GPL(input_ff_create); 356 357 /** 358 * input_ff_destroy() - frees force feedback portion of input device 359 * @dev: input device supporting force feedback 360 * 361 * This function is only needed in error path as input core will 362 * automatically free force feedback structures when device is 363 * destroyed. 364 */ 365 void input_ff_destroy(struct input_dev *dev) 366 { 367 struct ff_device *ff = dev->ff; 368 369 __clear_bit(EV_FF, dev->evbit); 370 if (ff) { 371 if (ff->destroy) 372 ff->destroy(ff); 373 kfree(ff->private); 374 kfree(ff->effects); 375 kfree(ff); 376 dev->ff = NULL; 377 } 378 } 379 EXPORT_SYMBOL_GPL(input_ff_destroy); 380