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); 369