1 /* 2 * devfreq_cooling: Thermal cooling device implementation for devices using 3 * devfreq 4 * 5 * Copyright (C) 2014-2015 ARM Limited 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 12 * kind, whether express or implied; without even the implied warranty 13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * TODO: 17 * - If OPPs are added or removed after devfreq cooling has 18 * registered, the devfreq cooling won't react to it. 19 */ 20 21 #include <linux/devfreq.h> 22 #include <linux/devfreq_cooling.h> 23 #include <linux/export.h> 24 #include <linux/slab.h> 25 #include <linux/pm_opp.h> 26 #include <linux/thermal.h> 27 28 #include <trace/events/thermal.h> 29 30 static DEFINE_MUTEX(devfreq_lock); 31 static DEFINE_IDR(devfreq_idr); 32 33 /** 34 * struct devfreq_cooling_device - Devfreq cooling device 35 * @id: unique integer value corresponding to each 36 * devfreq_cooling_device registered. 37 * @cdev: Pointer to associated thermal cooling device. 38 * @devfreq: Pointer to associated devfreq device. 39 * @cooling_state: Current cooling state. 40 * @power_table: Pointer to table with maximum power draw for each 41 * cooling state. State is the index into the table, and 42 * the power is in mW. 43 * @freq_table: Pointer to a table with the frequencies sorted in descending 44 * order. You can index the table by cooling device state 45 * @freq_table_size: Size of the @freq_table and @power_table 46 * @power_ops: Pointer to devfreq_cooling_power, used to generate the 47 * @power_table. 48 */ 49 struct devfreq_cooling_device { 50 int id; 51 struct thermal_cooling_device *cdev; 52 struct devfreq *devfreq; 53 unsigned long cooling_state; 54 u32 *power_table; 55 u32 *freq_table; 56 size_t freq_table_size; 57 struct devfreq_cooling_power *power_ops; 58 }; 59 60 /** 61 * get_idr - function to get a unique id. 62 * @idr: struct idr * handle used to create a id. 63 * @id: int * value generated by this function. 64 * 65 * This function will populate @id with an unique 66 * id, using the idr API. 67 * 68 * Return: 0 on success, an error code on failure. 69 */ 70 static int get_idr(struct idr *idr, int *id) 71 { 72 int ret; 73 74 mutex_lock(&devfreq_lock); 75 ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL); 76 mutex_unlock(&devfreq_lock); 77 if (unlikely(ret < 0)) 78 return ret; 79 *id = ret; 80 81 return 0; 82 } 83 84 /** 85 * release_idr - function to free the unique id. 86 * @idr: struct idr * handle used for creating the id. 87 * @id: int value representing the unique id. 88 */ 89 static void release_idr(struct idr *idr, int id) 90 { 91 mutex_lock(&devfreq_lock); 92 idr_remove(idr, id); 93 mutex_unlock(&devfreq_lock); 94 } 95 96 /** 97 * partition_enable_opps() - disable all opps above a given state 98 * @dfc: Pointer to devfreq we are operating on 99 * @cdev_state: cooling device state we're setting 100 * 101 * Go through the OPPs of the device, enabling all OPPs until 102 * @cdev_state and disabling those frequencies above it. 103 */ 104 static int partition_enable_opps(struct devfreq_cooling_device *dfc, 105 unsigned long cdev_state) 106 { 107 int i; 108 struct device *dev = dfc->devfreq->dev.parent; 109 110 for (i = 0; i < dfc->freq_table_size; i++) { 111 struct dev_pm_opp *opp; 112 int ret = 0; 113 unsigned int freq = dfc->freq_table[i]; 114 bool want_enable = i >= cdev_state ? true : false; 115 116 rcu_read_lock(); 117 opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable); 118 rcu_read_unlock(); 119 120 if (PTR_ERR(opp) == -ERANGE) 121 continue; 122 else if (IS_ERR(opp)) 123 return PTR_ERR(opp); 124 125 if (want_enable) 126 ret = dev_pm_opp_enable(dev, freq); 127 else 128 ret = dev_pm_opp_disable(dev, freq); 129 130 if (ret) 131 return ret; 132 } 133 134 return 0; 135 } 136 137 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev, 138 unsigned long *state) 139 { 140 struct devfreq_cooling_device *dfc = cdev->devdata; 141 142 *state = dfc->freq_table_size - 1; 143 144 return 0; 145 } 146 147 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev, 148 unsigned long *state) 149 { 150 struct devfreq_cooling_device *dfc = cdev->devdata; 151 152 *state = dfc->cooling_state; 153 154 return 0; 155 } 156 157 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev, 158 unsigned long state) 159 { 160 struct devfreq_cooling_device *dfc = cdev->devdata; 161 struct devfreq *df = dfc->devfreq; 162 struct device *dev = df->dev.parent; 163 int ret; 164 165 if (state == dfc->cooling_state) 166 return 0; 167 168 dev_dbg(dev, "Setting cooling state %lu\n", state); 169 170 if (state >= dfc->freq_table_size) 171 return -EINVAL; 172 173 ret = partition_enable_opps(dfc, state); 174 if (ret) 175 return ret; 176 177 dfc->cooling_state = state; 178 179 return 0; 180 } 181 182 /** 183 * freq_get_state() - get the cooling state corresponding to a frequency 184 * @dfc: Pointer to devfreq cooling device 185 * @freq: frequency in Hz 186 * 187 * Return: the cooling state associated with the @freq, or 188 * THERMAL_CSTATE_INVALID if it wasn't found. 189 */ 190 static unsigned long 191 freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq) 192 { 193 int i; 194 195 for (i = 0; i < dfc->freq_table_size; i++) { 196 if (dfc->freq_table[i] == freq) 197 return i; 198 } 199 200 return THERMAL_CSTATE_INVALID; 201 } 202 203 /** 204 * get_static_power() - calculate the static power 205 * @dfc: Pointer to devfreq cooling device 206 * @freq: Frequency in Hz 207 * 208 * Calculate the static power in milliwatts using the supplied 209 * get_static_power(). The current voltage is calculated using the 210 * OPP library. If no get_static_power() was supplied, assume the 211 * static power is negligible. 212 */ 213 static unsigned long 214 get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq) 215 { 216 struct devfreq *df = dfc->devfreq; 217 struct device *dev = df->dev.parent; 218 unsigned long voltage; 219 struct dev_pm_opp *opp; 220 221 if (!dfc->power_ops->get_static_power) 222 return 0; 223 224 rcu_read_lock(); 225 226 opp = dev_pm_opp_find_freq_exact(dev, freq, true); 227 if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE)) 228 opp = dev_pm_opp_find_freq_exact(dev, freq, false); 229 230 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ 231 232 rcu_read_unlock(); 233 234 if (voltage == 0) { 235 dev_warn_ratelimited(dev, 236 "Failed to get voltage for frequency %lu: %ld\n", 237 freq, IS_ERR(opp) ? PTR_ERR(opp) : 0); 238 return 0; 239 } 240 241 return dfc->power_ops->get_static_power(voltage); 242 } 243 244 /** 245 * get_dynamic_power - calculate the dynamic power 246 * @dfc: Pointer to devfreq cooling device 247 * @freq: Frequency in Hz 248 * @voltage: Voltage in millivolts 249 * 250 * Calculate the dynamic power in milliwatts consumed by the device at 251 * frequency @freq and voltage @voltage. If the get_dynamic_power() 252 * was supplied as part of the devfreq_cooling_power struct, then that 253 * function is used. Otherwise, a simple power model (Pdyn = Coeff * 254 * Voltage^2 * Frequency) is used. 255 */ 256 static unsigned long 257 get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq, 258 unsigned long voltage) 259 { 260 u64 power; 261 u32 freq_mhz; 262 struct devfreq_cooling_power *dfc_power = dfc->power_ops; 263 264 if (dfc_power->get_dynamic_power) 265 return dfc_power->get_dynamic_power(freq, voltage); 266 267 freq_mhz = freq / 1000000; 268 power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage; 269 do_div(power, 1000000000); 270 271 return power; 272 } 273 274 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev, 275 struct thermal_zone_device *tz, 276 u32 *power) 277 { 278 struct devfreq_cooling_device *dfc = cdev->devdata; 279 struct devfreq *df = dfc->devfreq; 280 struct devfreq_dev_status *status = &df->last_status; 281 unsigned long state; 282 unsigned long freq = status->current_frequency; 283 u32 dyn_power, static_power; 284 285 /* Get dynamic power for state */ 286 state = freq_get_state(dfc, freq); 287 if (state == THERMAL_CSTATE_INVALID) 288 return -EAGAIN; 289 290 dyn_power = dfc->power_table[state]; 291 292 /* Scale dynamic power for utilization */ 293 dyn_power = (dyn_power * status->busy_time) / status->total_time; 294 295 /* Get static power */ 296 static_power = get_static_power(dfc, freq); 297 298 trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power, 299 static_power); 300 301 *power = dyn_power + static_power; 302 303 return 0; 304 } 305 306 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev, 307 struct thermal_zone_device *tz, 308 unsigned long state, 309 u32 *power) 310 { 311 struct devfreq_cooling_device *dfc = cdev->devdata; 312 unsigned long freq; 313 u32 static_power; 314 315 if (state >= dfc->freq_table_size) 316 return -EINVAL; 317 318 freq = dfc->freq_table[state]; 319 static_power = get_static_power(dfc, freq); 320 321 *power = dfc->power_table[state] + static_power; 322 return 0; 323 } 324 325 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev, 326 struct thermal_zone_device *tz, 327 u32 power, unsigned long *state) 328 { 329 struct devfreq_cooling_device *dfc = cdev->devdata; 330 struct devfreq *df = dfc->devfreq; 331 struct devfreq_dev_status *status = &df->last_status; 332 unsigned long freq = status->current_frequency; 333 unsigned long busy_time; 334 s32 dyn_power; 335 u32 static_power; 336 int i; 337 338 static_power = get_static_power(dfc, freq); 339 340 dyn_power = power - static_power; 341 dyn_power = dyn_power > 0 ? dyn_power : 0; 342 343 /* Scale dynamic power for utilization */ 344 busy_time = status->busy_time ?: 1; 345 dyn_power = (dyn_power * status->total_time) / busy_time; 346 347 /* 348 * Find the first cooling state that is within the power 349 * budget for dynamic power. 350 */ 351 for (i = 0; i < dfc->freq_table_size - 1; i++) 352 if (dyn_power >= dfc->power_table[i]) 353 break; 354 355 *state = i; 356 trace_thermal_power_devfreq_limit(cdev, freq, *state, power); 357 return 0; 358 } 359 360 static struct thermal_cooling_device_ops devfreq_cooling_ops = { 361 .get_max_state = devfreq_cooling_get_max_state, 362 .get_cur_state = devfreq_cooling_get_cur_state, 363 .set_cur_state = devfreq_cooling_set_cur_state, 364 }; 365 366 /** 367 * devfreq_cooling_gen_tables() - Generate power and freq tables. 368 * @dfc: Pointer to devfreq cooling device. 369 * 370 * Generate power and frequency tables: the power table hold the 371 * device's maximum power usage at each cooling state (OPP). The 372 * static and dynamic power using the appropriate voltage and 373 * frequency for the state, is acquired from the struct 374 * devfreq_cooling_power, and summed to make the maximum power draw. 375 * 376 * The frequency table holds the frequencies in descending order. 377 * That way its indexed by cooling device state. 378 * 379 * The tables are malloced, and pointers put in dfc. They must be 380 * freed when unregistering the devfreq cooling device. 381 * 382 * Return: 0 on success, negative error code on failure. 383 */ 384 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc) 385 { 386 struct devfreq *df = dfc->devfreq; 387 struct device *dev = df->dev.parent; 388 int ret, num_opps; 389 unsigned long freq; 390 u32 *power_table = NULL; 391 u32 *freq_table; 392 int i; 393 394 num_opps = dev_pm_opp_get_opp_count(dev); 395 396 if (dfc->power_ops) { 397 power_table = kcalloc(num_opps, sizeof(*power_table), 398 GFP_KERNEL); 399 if (!power_table) 400 return -ENOMEM; 401 } 402 403 freq_table = kcalloc(num_opps, sizeof(*freq_table), 404 GFP_KERNEL); 405 if (!freq_table) { 406 ret = -ENOMEM; 407 goto free_power_table; 408 } 409 410 for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) { 411 unsigned long power_dyn, voltage; 412 struct dev_pm_opp *opp; 413 414 rcu_read_lock(); 415 416 opp = dev_pm_opp_find_freq_floor(dev, &freq); 417 if (IS_ERR(opp)) { 418 rcu_read_unlock(); 419 ret = PTR_ERR(opp); 420 goto free_tables; 421 } 422 423 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ 424 425 rcu_read_unlock(); 426 427 if (dfc->power_ops) { 428 power_dyn = get_dynamic_power(dfc, freq, voltage); 429 430 dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n", 431 freq / 1000000, voltage, power_dyn, power_dyn); 432 433 power_table[i] = power_dyn; 434 } 435 436 freq_table[i] = freq; 437 } 438 439 if (dfc->power_ops) 440 dfc->power_table = power_table; 441 442 dfc->freq_table = freq_table; 443 dfc->freq_table_size = num_opps; 444 445 return 0; 446 447 free_tables: 448 kfree(freq_table); 449 free_power_table: 450 kfree(power_table); 451 452 return ret; 453 } 454 455 /** 456 * of_devfreq_cooling_register_power() - Register devfreq cooling device, 457 * with OF and power information. 458 * @np: Pointer to OF device_node. 459 * @df: Pointer to devfreq device. 460 * @dfc_power: Pointer to devfreq_cooling_power. 461 * 462 * Register a devfreq cooling device. The available OPPs must be 463 * registered on the device. 464 * 465 * If @dfc_power is provided, the cooling device is registered with the 466 * power extensions. For the power extensions to work correctly, 467 * devfreq should use the simple_ondemand governor, other governors 468 * are not currently supported. 469 */ 470 struct thermal_cooling_device * 471 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, 472 struct devfreq_cooling_power *dfc_power) 473 { 474 struct thermal_cooling_device *cdev; 475 struct devfreq_cooling_device *dfc; 476 char dev_name[THERMAL_NAME_LENGTH]; 477 int err; 478 479 dfc = kzalloc(sizeof(*dfc), GFP_KERNEL); 480 if (!dfc) 481 return ERR_PTR(-ENOMEM); 482 483 dfc->devfreq = df; 484 485 if (dfc_power) { 486 dfc->power_ops = dfc_power; 487 488 devfreq_cooling_ops.get_requested_power = 489 devfreq_cooling_get_requested_power; 490 devfreq_cooling_ops.state2power = devfreq_cooling_state2power; 491 devfreq_cooling_ops.power2state = devfreq_cooling_power2state; 492 } 493 494 err = devfreq_cooling_gen_tables(dfc); 495 if (err) 496 goto free_dfc; 497 498 err = get_idr(&devfreq_idr, &dfc->id); 499 if (err) 500 goto free_tables; 501 502 snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id); 503 504 cdev = thermal_of_cooling_device_register(np, dev_name, dfc, 505 &devfreq_cooling_ops); 506 if (IS_ERR(cdev)) { 507 err = PTR_ERR(cdev); 508 dev_err(df->dev.parent, 509 "Failed to register devfreq cooling device (%d)\n", 510 err); 511 goto release_idr; 512 } 513 514 dfc->cdev = cdev; 515 516 return cdev; 517 518 release_idr: 519 release_idr(&devfreq_idr, dfc->id); 520 free_tables: 521 kfree(dfc->power_table); 522 kfree(dfc->freq_table); 523 free_dfc: 524 kfree(dfc); 525 526 return ERR_PTR(err); 527 } 528 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power); 529 530 /** 531 * of_devfreq_cooling_register() - Register devfreq cooling device, 532 * with OF information. 533 * @np: Pointer to OF device_node. 534 * @df: Pointer to devfreq device. 535 */ 536 struct thermal_cooling_device * 537 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df) 538 { 539 return of_devfreq_cooling_register_power(np, df, NULL); 540 } 541 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register); 542 543 /** 544 * devfreq_cooling_register() - Register devfreq cooling device. 545 * @df: Pointer to devfreq device. 546 */ 547 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df) 548 { 549 return of_devfreq_cooling_register(NULL, df); 550 } 551 EXPORT_SYMBOL_GPL(devfreq_cooling_register); 552 553 /** 554 * devfreq_cooling_unregister() - Unregister devfreq cooling device. 555 * @dfc: Pointer to devfreq cooling device to unregister. 556 */ 557 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) 558 { 559 struct devfreq_cooling_device *dfc; 560 561 if (!cdev) 562 return; 563 564 dfc = cdev->devdata; 565 566 thermal_cooling_device_unregister(dfc->cdev); 567 release_idr(&devfreq_idr, dfc->id); 568 kfree(dfc->power_table); 569 kfree(dfc->freq_table); 570 571 kfree(dfc); 572 } 573 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister); 574