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/idr.h> 25 #include <linux/slab.h> 26 #include <linux/pm_opp.h> 27 #include <linux/pm_qos.h> 28 #include <linux/thermal.h> 29 30 #include <trace/events/thermal.h> 31 32 #define HZ_PER_KHZ 1000 33 #define SCALE_ERROR_MITIGATION 100 34 35 static DEFINE_IDA(devfreq_ida); 36 37 /** 38 * struct devfreq_cooling_device - Devfreq cooling device 39 * @id: unique integer value corresponding to each 40 * devfreq_cooling_device registered. 41 * @cdev: Pointer to associated thermal cooling device. 42 * @devfreq: Pointer to associated devfreq device. 43 * @cooling_state: Current cooling state. 44 * @power_table: Pointer to table with maximum power draw for each 45 * cooling state. State is the index into the table, and 46 * the power is in mW. 47 * @freq_table: Pointer to a table with the frequencies sorted in descending 48 * order. You can index the table by cooling device state 49 * @freq_table_size: Size of the @freq_table and @power_table 50 * @power_ops: Pointer to devfreq_cooling_power, used to generate the 51 * @power_table. 52 * @res_util: Resource utilization scaling factor for the power. 53 * It is multiplied by 100 to minimize the error. It is used 54 * for estimation of the power budget instead of using 55 * 'utilization' (which is 'busy_time / 'total_time'). 56 * The 'res_util' range is from 100 to (power_table[state] * 100) 57 * for the corresponding 'state'. 58 * @capped_state: index to cooling state with in dynamic power budget 59 * @req_max_freq: PM QoS request for limiting the maximum frequency 60 * of the devfreq device. 61 */ 62 struct devfreq_cooling_device { 63 int id; 64 struct thermal_cooling_device *cdev; 65 struct devfreq *devfreq; 66 unsigned long cooling_state; 67 u32 *power_table; 68 u32 *freq_table; 69 size_t freq_table_size; 70 struct devfreq_cooling_power *power_ops; 71 u32 res_util; 72 int capped_state; 73 struct dev_pm_qos_request req_max_freq; 74 }; 75 76 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev, 77 unsigned long *state) 78 { 79 struct devfreq_cooling_device *dfc = cdev->devdata; 80 81 *state = dfc->freq_table_size - 1; 82 83 return 0; 84 } 85 86 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev, 87 unsigned long *state) 88 { 89 struct devfreq_cooling_device *dfc = cdev->devdata; 90 91 *state = dfc->cooling_state; 92 93 return 0; 94 } 95 96 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev, 97 unsigned long state) 98 { 99 struct devfreq_cooling_device *dfc = cdev->devdata; 100 struct devfreq *df = dfc->devfreq; 101 struct device *dev = df->dev.parent; 102 unsigned long freq; 103 104 if (state == dfc->cooling_state) 105 return 0; 106 107 dev_dbg(dev, "Setting cooling state %lu\n", state); 108 109 if (state >= dfc->freq_table_size) 110 return -EINVAL; 111 112 freq = dfc->freq_table[state]; 113 114 dev_pm_qos_update_request(&dfc->req_max_freq, 115 DIV_ROUND_UP(freq, HZ_PER_KHZ)); 116 117 dfc->cooling_state = state; 118 119 return 0; 120 } 121 122 /** 123 * freq_get_state() - get the cooling state corresponding to a frequency 124 * @dfc: Pointer to devfreq cooling device 125 * @freq: frequency in Hz 126 * 127 * Return: the cooling state associated with the @freq, or 128 * THERMAL_CSTATE_INVALID if it wasn't found. 129 */ 130 static unsigned long 131 freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq) 132 { 133 int i; 134 135 for (i = 0; i < dfc->freq_table_size; i++) { 136 if (dfc->freq_table[i] == freq) 137 return i; 138 } 139 140 return THERMAL_CSTATE_INVALID; 141 } 142 143 static unsigned long get_voltage(struct devfreq *df, unsigned long freq) 144 { 145 struct device *dev = df->dev.parent; 146 unsigned long voltage; 147 struct dev_pm_opp *opp; 148 149 opp = dev_pm_opp_find_freq_exact(dev, freq, true); 150 if (PTR_ERR(opp) == -ERANGE) 151 opp = dev_pm_opp_find_freq_exact(dev, freq, false); 152 153 if (IS_ERR(opp)) { 154 dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n", 155 freq, PTR_ERR(opp)); 156 return 0; 157 } 158 159 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ 160 dev_pm_opp_put(opp); 161 162 if (voltage == 0) { 163 dev_err_ratelimited(dev, 164 "Failed to get voltage for frequency %lu\n", 165 freq); 166 } 167 168 return voltage; 169 } 170 171 /** 172 * get_static_power() - calculate the static power 173 * @dfc: Pointer to devfreq cooling device 174 * @freq: Frequency in Hz 175 * 176 * Calculate the static power in milliwatts using the supplied 177 * get_static_power(). The current voltage is calculated using the 178 * OPP library. If no get_static_power() was supplied, assume the 179 * static power is negligible. 180 */ 181 static unsigned long 182 get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq) 183 { 184 struct devfreq *df = dfc->devfreq; 185 unsigned long voltage; 186 187 if (!dfc->power_ops->get_static_power) 188 return 0; 189 190 voltage = get_voltage(df, freq); 191 192 if (voltage == 0) 193 return 0; 194 195 return dfc->power_ops->get_static_power(df, voltage); 196 } 197 198 /** 199 * get_dynamic_power - calculate the dynamic power 200 * @dfc: Pointer to devfreq cooling device 201 * @freq: Frequency in Hz 202 * @voltage: Voltage in millivolts 203 * 204 * Calculate the dynamic power in milliwatts consumed by the device at 205 * frequency @freq and voltage @voltage. If the get_dynamic_power() 206 * was supplied as part of the devfreq_cooling_power struct, then that 207 * function is used. Otherwise, a simple power model (Pdyn = Coeff * 208 * Voltage^2 * Frequency) is used. 209 */ 210 static unsigned long 211 get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq, 212 unsigned long voltage) 213 { 214 u64 power; 215 u32 freq_mhz; 216 struct devfreq_cooling_power *dfc_power = dfc->power_ops; 217 218 if (dfc_power->get_dynamic_power) 219 return dfc_power->get_dynamic_power(dfc->devfreq, freq, 220 voltage); 221 222 freq_mhz = freq / 1000000; 223 power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage; 224 do_div(power, 1000000000); 225 226 return power; 227 } 228 229 230 static inline unsigned long get_total_power(struct devfreq_cooling_device *dfc, 231 unsigned long freq, 232 unsigned long voltage) 233 { 234 return get_static_power(dfc, freq) + get_dynamic_power(dfc, freq, 235 voltage); 236 } 237 238 239 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev, 240 struct thermal_zone_device *tz, 241 u32 *power) 242 { 243 struct devfreq_cooling_device *dfc = cdev->devdata; 244 struct devfreq *df = dfc->devfreq; 245 struct devfreq_dev_status *status = &df->last_status; 246 unsigned long state; 247 unsigned long freq = status->current_frequency; 248 unsigned long voltage; 249 u32 dyn_power = 0; 250 u32 static_power = 0; 251 int res; 252 253 state = freq_get_state(dfc, freq); 254 if (state == THERMAL_CSTATE_INVALID) { 255 res = -EAGAIN; 256 goto fail; 257 } 258 259 if (dfc->power_ops->get_real_power) { 260 voltage = get_voltage(df, freq); 261 if (voltage == 0) { 262 res = -EINVAL; 263 goto fail; 264 } 265 266 res = dfc->power_ops->get_real_power(df, power, freq, voltage); 267 if (!res) { 268 state = dfc->capped_state; 269 dfc->res_util = dfc->power_table[state]; 270 dfc->res_util *= SCALE_ERROR_MITIGATION; 271 272 if (*power > 1) 273 dfc->res_util /= *power; 274 } else { 275 goto fail; 276 } 277 } else { 278 dyn_power = dfc->power_table[state]; 279 280 /* Scale dynamic power for utilization */ 281 dyn_power *= status->busy_time; 282 dyn_power /= status->total_time; 283 /* Get static power */ 284 static_power = get_static_power(dfc, freq); 285 286 *power = dyn_power + static_power; 287 } 288 289 trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power, 290 static_power, *power); 291 292 return 0; 293 fail: 294 /* It is safe to set max in this case */ 295 dfc->res_util = SCALE_ERROR_MITIGATION; 296 return res; 297 } 298 299 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev, 300 struct thermal_zone_device *tz, 301 unsigned long state, 302 u32 *power) 303 { 304 struct devfreq_cooling_device *dfc = cdev->devdata; 305 unsigned long freq; 306 u32 static_power; 307 308 if (state >= dfc->freq_table_size) 309 return -EINVAL; 310 311 freq = dfc->freq_table[state]; 312 static_power = get_static_power(dfc, freq); 313 314 *power = dfc->power_table[state] + static_power; 315 return 0; 316 } 317 318 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev, 319 struct thermal_zone_device *tz, 320 u32 power, unsigned long *state) 321 { 322 struct devfreq_cooling_device *dfc = cdev->devdata; 323 struct devfreq *df = dfc->devfreq; 324 struct devfreq_dev_status *status = &df->last_status; 325 unsigned long freq = status->current_frequency; 326 unsigned long busy_time; 327 s32 dyn_power; 328 u32 static_power; 329 s32 est_power; 330 int i; 331 332 if (dfc->power_ops->get_real_power) { 333 /* Scale for resource utilization */ 334 est_power = power * dfc->res_util; 335 est_power /= SCALE_ERROR_MITIGATION; 336 } else { 337 static_power = get_static_power(dfc, freq); 338 339 dyn_power = power - static_power; 340 dyn_power = dyn_power > 0 ? dyn_power : 0; 341 342 /* Scale dynamic power for utilization */ 343 busy_time = status->busy_time ?: 1; 344 est_power = (dyn_power * status->total_time) / busy_time; 345 } 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 (est_power >= dfc->power_table[i]) 353 break; 354 355 *state = i; 356 dfc->capped_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, voltage; 413 struct dev_pm_opp *opp; 414 415 opp = dev_pm_opp_find_freq_floor(dev, &freq); 416 if (IS_ERR(opp)) { 417 ret = PTR_ERR(opp); 418 goto free_tables; 419 } 420 421 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ 422 dev_pm_opp_put(opp); 423 424 if (dfc->power_ops) { 425 if (dfc->power_ops->get_real_power) 426 power = get_total_power(dfc, freq, voltage); 427 else 428 power = get_dynamic_power(dfc, freq, voltage); 429 430 dev_dbg(dev, "Power table: %lu MHz @ %lu mV: %lu = %lu mW\n", 431 freq / 1000000, voltage, power, power); 432 433 power_table[i] = power; 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 = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq, 499 DEV_PM_QOS_MAX_FREQUENCY, 500 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE); 501 if (err < 0) 502 goto free_tables; 503 504 err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL); 505 if (err < 0) 506 goto remove_qos_req; 507 dfc->id = err; 508 509 snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id); 510 511 cdev = thermal_of_cooling_device_register(np, dev_name, dfc, 512 &devfreq_cooling_ops); 513 if (IS_ERR(cdev)) { 514 err = PTR_ERR(cdev); 515 dev_err(df->dev.parent, 516 "Failed to register devfreq cooling device (%d)\n", 517 err); 518 goto release_ida; 519 } 520 521 dfc->cdev = cdev; 522 523 return cdev; 524 525 release_ida: 526 ida_simple_remove(&devfreq_ida, dfc->id); 527 528 remove_qos_req: 529 dev_pm_qos_remove_request(&dfc->req_max_freq); 530 531 free_tables: 532 kfree(dfc->power_table); 533 kfree(dfc->freq_table); 534 free_dfc: 535 kfree(dfc); 536 537 return ERR_PTR(err); 538 } 539 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power); 540 541 /** 542 * of_devfreq_cooling_register() - Register devfreq cooling device, 543 * with OF information. 544 * @np: Pointer to OF device_node. 545 * @df: Pointer to devfreq device. 546 */ 547 struct thermal_cooling_device * 548 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df) 549 { 550 return of_devfreq_cooling_register_power(np, df, NULL); 551 } 552 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register); 553 554 /** 555 * devfreq_cooling_register() - Register devfreq cooling device. 556 * @df: Pointer to devfreq device. 557 */ 558 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df) 559 { 560 return of_devfreq_cooling_register(NULL, df); 561 } 562 EXPORT_SYMBOL_GPL(devfreq_cooling_register); 563 564 /** 565 * devfreq_cooling_unregister() - Unregister devfreq cooling device. 566 * @cdev: Pointer to devfreq cooling device to unregister. 567 */ 568 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) 569 { 570 struct devfreq_cooling_device *dfc; 571 572 if (!cdev) 573 return; 574 575 dfc = cdev->devdata; 576 577 thermal_cooling_device_unregister(dfc->cdev); 578 ida_simple_remove(&devfreq_ida, dfc->id); 579 dev_pm_qos_remove_request(&dfc->req_max_freq); 580 kfree(dfc->power_table); 581 kfree(dfc->freq_table); 582 583 kfree(dfc); 584 } 585 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister); 586