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(df, 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(dfc->devfreq, freq, 266 voltage); 267 268 freq_mhz = freq / 1000000; 269 power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage; 270 do_div(power, 1000000000); 271 272 return power; 273 } 274 275 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev, 276 struct thermal_zone_device *tz, 277 u32 *power) 278 { 279 struct devfreq_cooling_device *dfc = cdev->devdata; 280 struct devfreq *df = dfc->devfreq; 281 struct devfreq_dev_status *status = &df->last_status; 282 unsigned long state; 283 unsigned long freq = status->current_frequency; 284 u32 dyn_power, static_power; 285 286 /* Get dynamic power for state */ 287 state = freq_get_state(dfc, freq); 288 if (state == THERMAL_CSTATE_INVALID) 289 return -EAGAIN; 290 291 dyn_power = dfc->power_table[state]; 292 293 /* Scale dynamic power for utilization */ 294 dyn_power = (dyn_power * status->busy_time) / status->total_time; 295 296 /* Get static power */ 297 static_power = get_static_power(dfc, freq); 298 299 trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power, 300 static_power); 301 302 *power = dyn_power + static_power; 303 304 return 0; 305 } 306 307 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev, 308 struct thermal_zone_device *tz, 309 unsigned long state, 310 u32 *power) 311 { 312 struct devfreq_cooling_device *dfc = cdev->devdata; 313 unsigned long freq; 314 u32 static_power; 315 316 if (state >= dfc->freq_table_size) 317 return -EINVAL; 318 319 freq = dfc->freq_table[state]; 320 static_power = get_static_power(dfc, freq); 321 322 *power = dfc->power_table[state] + static_power; 323 return 0; 324 } 325 326 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev, 327 struct thermal_zone_device *tz, 328 u32 power, unsigned long *state) 329 { 330 struct devfreq_cooling_device *dfc = cdev->devdata; 331 struct devfreq *df = dfc->devfreq; 332 struct devfreq_dev_status *status = &df->last_status; 333 unsigned long freq = status->current_frequency; 334 unsigned long busy_time; 335 s32 dyn_power; 336 u32 static_power; 337 int i; 338 339 static_power = get_static_power(dfc, freq); 340 341 dyn_power = power - static_power; 342 dyn_power = dyn_power > 0 ? dyn_power : 0; 343 344 /* Scale dynamic power for utilization */ 345 busy_time = status->busy_time ?: 1; 346 dyn_power = (dyn_power * status->total_time) / busy_time; 347 348 /* 349 * Find the first cooling state that is within the power 350 * budget for dynamic power. 351 */ 352 for (i = 0; i < dfc->freq_table_size - 1; i++) 353 if (dyn_power >= dfc->power_table[i]) 354 break; 355 356 *state = i; 357 trace_thermal_power_devfreq_limit(cdev, freq, *state, power); 358 return 0; 359 } 360 361 static struct thermal_cooling_device_ops devfreq_cooling_ops = { 362 .get_max_state = devfreq_cooling_get_max_state, 363 .get_cur_state = devfreq_cooling_get_cur_state, 364 .set_cur_state = devfreq_cooling_set_cur_state, 365 }; 366 367 /** 368 * devfreq_cooling_gen_tables() - Generate power and freq tables. 369 * @dfc: Pointer to devfreq cooling device. 370 * 371 * Generate power and frequency tables: the power table hold the 372 * device's maximum power usage at each cooling state (OPP). The 373 * static and dynamic power using the appropriate voltage and 374 * frequency for the state, is acquired from the struct 375 * devfreq_cooling_power, and summed to make the maximum power draw. 376 * 377 * The frequency table holds the frequencies in descending order. 378 * That way its indexed by cooling device state. 379 * 380 * The tables are malloced, and pointers put in dfc. They must be 381 * freed when unregistering the devfreq cooling device. 382 * 383 * Return: 0 on success, negative error code on failure. 384 */ 385 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc) 386 { 387 struct devfreq *df = dfc->devfreq; 388 struct device *dev = df->dev.parent; 389 int ret, num_opps; 390 unsigned long freq; 391 u32 *power_table = NULL; 392 u32 *freq_table; 393 int i; 394 395 num_opps = dev_pm_opp_get_opp_count(dev); 396 397 if (dfc->power_ops) { 398 power_table = kcalloc(num_opps, sizeof(*power_table), 399 GFP_KERNEL); 400 if (!power_table) 401 return -ENOMEM; 402 } 403 404 freq_table = kcalloc(num_opps, sizeof(*freq_table), 405 GFP_KERNEL); 406 if (!freq_table) { 407 ret = -ENOMEM; 408 goto free_power_table; 409 } 410 411 for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) { 412 unsigned long power_dyn, voltage; 413 struct dev_pm_opp *opp; 414 415 rcu_read_lock(); 416 417 opp = dev_pm_opp_find_freq_floor(dev, &freq); 418 if (IS_ERR(opp)) { 419 rcu_read_unlock(); 420 ret = PTR_ERR(opp); 421 goto free_tables; 422 } 423 424 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ 425 426 rcu_read_unlock(); 427 428 if (dfc->power_ops) { 429 power_dyn = get_dynamic_power(dfc, freq, voltage); 430 431 dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n", 432 freq / 1000000, voltage, power_dyn, power_dyn); 433 434 power_table[i] = power_dyn; 435 } 436 437 freq_table[i] = freq; 438 } 439 440 if (dfc->power_ops) 441 dfc->power_table = power_table; 442 443 dfc->freq_table = freq_table; 444 dfc->freq_table_size = num_opps; 445 446 return 0; 447 448 free_tables: 449 kfree(freq_table); 450 free_power_table: 451 kfree(power_table); 452 453 return ret; 454 } 455 456 /** 457 * of_devfreq_cooling_register_power() - Register devfreq cooling device, 458 * with OF and power information. 459 * @np: Pointer to OF device_node. 460 * @df: Pointer to devfreq device. 461 * @dfc_power: Pointer to devfreq_cooling_power. 462 * 463 * Register a devfreq cooling device. The available OPPs must be 464 * registered on the device. 465 * 466 * If @dfc_power is provided, the cooling device is registered with the 467 * power extensions. For the power extensions to work correctly, 468 * devfreq should use the simple_ondemand governor, other governors 469 * are not currently supported. 470 */ 471 struct thermal_cooling_device * 472 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, 473 struct devfreq_cooling_power *dfc_power) 474 { 475 struct thermal_cooling_device *cdev; 476 struct devfreq_cooling_device *dfc; 477 char dev_name[THERMAL_NAME_LENGTH]; 478 int err; 479 480 dfc = kzalloc(sizeof(*dfc), GFP_KERNEL); 481 if (!dfc) 482 return ERR_PTR(-ENOMEM); 483 484 dfc->devfreq = df; 485 486 if (dfc_power) { 487 dfc->power_ops = dfc_power; 488 489 devfreq_cooling_ops.get_requested_power = 490 devfreq_cooling_get_requested_power; 491 devfreq_cooling_ops.state2power = devfreq_cooling_state2power; 492 devfreq_cooling_ops.power2state = devfreq_cooling_power2state; 493 } 494 495 err = devfreq_cooling_gen_tables(dfc); 496 if (err) 497 goto free_dfc; 498 499 err = get_idr(&devfreq_idr, &dfc->id); 500 if (err) 501 goto free_tables; 502 503 snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id); 504 505 cdev = thermal_of_cooling_device_register(np, dev_name, dfc, 506 &devfreq_cooling_ops); 507 if (IS_ERR(cdev)) { 508 err = PTR_ERR(cdev); 509 dev_err(df->dev.parent, 510 "Failed to register devfreq cooling device (%d)\n", 511 err); 512 goto release_idr; 513 } 514 515 dfc->cdev = cdev; 516 517 return cdev; 518 519 release_idr: 520 release_idr(&devfreq_idr, dfc->id); 521 free_tables: 522 kfree(dfc->power_table); 523 kfree(dfc->freq_table); 524 free_dfc: 525 kfree(dfc); 526 527 return ERR_PTR(err); 528 } 529 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power); 530 531 /** 532 * of_devfreq_cooling_register() - Register devfreq cooling device, 533 * with OF information. 534 * @np: Pointer to OF device_node. 535 * @df: Pointer to devfreq device. 536 */ 537 struct thermal_cooling_device * 538 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df) 539 { 540 return of_devfreq_cooling_register_power(np, df, NULL); 541 } 542 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register); 543 544 /** 545 * devfreq_cooling_register() - Register devfreq cooling device. 546 * @df: Pointer to devfreq device. 547 */ 548 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df) 549 { 550 return of_devfreq_cooling_register(NULL, df); 551 } 552 EXPORT_SYMBOL_GPL(devfreq_cooling_register); 553 554 /** 555 * devfreq_cooling_unregister() - Unregister devfreq cooling device. 556 * @dfc: Pointer to devfreq cooling device to unregister. 557 */ 558 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) 559 { 560 struct devfreq_cooling_device *dfc; 561 562 if (!cdev) 563 return; 564 565 dfc = cdev->devdata; 566 567 thermal_cooling_device_unregister(dfc->cdev); 568 release_idr(&devfreq_idr, dfc->id); 569 kfree(dfc->power_table); 570 kfree(dfc->freq_table); 571 572 kfree(dfc); 573 } 574 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister); 575