drivers/thermal/devfreq_cooling.c

   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/thermal.h>
  28
  29 #include <trace/events/thermal.h>
  30
  31 #define SCALE_ERROR_MITIGATION 100
  32
  33 static DEFINE_IDA(devfreq_ida);
  34
  35 /**
  36  * struct devfreq_cooling_device - Devfreq cooling device
  37  * @id:         unique integer value corresponding to each
  38  *              devfreq_cooling_device registered.
  39  * @cdev:       Pointer to associated thermal cooling device.
  40  * @devfreq:    Pointer to associated devfreq device.
  41  * @cooling_state:      Current cooling state.
  42  * @power_table:        Pointer to table with maximum power draw for each
  43  *                      cooling state. State is the index into the table, and
  44  *                      the power is in mW.
  45  * @freq_table: Pointer to a table with the frequencies sorted in descending
  46  *              order.  You can index the table by cooling device state
  47  * @freq_table_size:    Size of the @freq_table and @power_table
  48  * @power_ops:  Pointer to devfreq_cooling_power, used to generate the
  49  *              @power_table.
  50  * @res_util:   Resource utilization scaling factor for the power.
  51  *              It is multiplied by 100 to minimize the error. It is used
  52  *              for estimation of the power budget instead of using
  53  *              'utilization' (which is 'busy_time / 'total_time').
  54  *              The 'res_util' range is from 100 to (power_table[state] * 100)
  55  *              for the corresponding 'state'.
  56  * @capped_state:       index to cooling state with in dynamic power budget
  57  */
  58 struct devfreq_cooling_device {
  59         int id;
  60         struct thermal_cooling_device *cdev;
  61         struct devfreq *devfreq;
  62         unsigned long cooling_state;
  63         u32 *power_table;
  64         u32 *freq_table;
  65         size_t freq_table_size;
  66         struct devfreq_cooling_power *power_ops;
  67         u32 res_util;
  68         int capped_state;
  69 };
  70
  71 /**
  72  * partition_enable_opps() - disable all opps above a given state
  73  * @dfc:        Pointer to devfreq we are operating on
  74  * @cdev_state: cooling device state we're setting
  75  *
  76  * Go through the OPPs of the device, enabling all OPPs until
  77  * @cdev_state and disabling those frequencies above it.
  78  */
  79 static int partition_enable_opps(struct devfreq_cooling_device *dfc,
  80                                  unsigned long cdev_state)
  81 {
  82         int i;
  83         struct device *dev = dfc->devfreq->dev.parent;
  84
  85         for (i = 0; i < dfc->freq_table_size; i++) {
  86                 struct dev_pm_opp *opp;
  87                 int ret = 0;
  88                 unsigned int freq = dfc->freq_table[i];
  89                 bool want_enable = i >= cdev_state ? true : false;
  90
  91                 opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
  92
  93                 if (PTR_ERR(opp) == -ERANGE)
  94                         continue;
  95                 else if (IS_ERR(opp))
  96                         return PTR_ERR(opp);
  97
  98                 dev_pm_opp_put(opp);
  99
 100                 if (want_enable)
 101                         ret = dev_pm_opp_enable(dev, freq);
 102                 else
 103                         ret = dev_pm_opp_disable(dev, freq);
 104
 105                 if (ret)
 106                         return ret;
 107         }
 108
 109         return 0;
 110 }
 111
 112 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
 113                                          unsigned long *state)
 114 {
 115         struct devfreq_cooling_device *dfc = cdev->devdata;
 116
 117         *state = dfc->freq_table_size - 1;
 118
 119         return 0;
 120 }
 121
 122 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
 123                                          unsigned long *state)
 124 {
 125         struct devfreq_cooling_device *dfc = cdev->devdata;
 126
 127         *state = dfc->cooling_state;
 128
 129         return 0;
 130 }
 131
 132 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
 133                                          unsigned long state)
 134 {
 135         struct devfreq_cooling_device *dfc = cdev->devdata;
 136         struct devfreq *df = dfc->devfreq;
 137         struct device *dev = df->dev.parent;
 138         int ret;
 139
 140         if (state == dfc->cooling_state)
 141                 return 0;
 142
 143         dev_dbg(dev, "Setting cooling state %lu\n", state);
 144
 145         if (state >= dfc->freq_table_size)
 146                 return -EINVAL;
 147
 148         ret = partition_enable_opps(dfc, state);
 149         if (ret)
 150                 return ret;
 151
 152         dfc->cooling_state = state;
 153
 154         return 0;
 155 }
 156
 157 /**
 158  * freq_get_state() - get the cooling state corresponding to a frequency
 159  * @dfc:        Pointer to devfreq cooling device
 160  * @freq:       frequency in Hz
 161  *
 162  * Return: the cooling state associated with the @freq, or
 163  * THERMAL_CSTATE_INVALID if it wasn't found.
 164  */
 165 static unsigned long
 166 freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq)
 167 {
 168         int i;
 169
 170         for (i = 0; i < dfc->freq_table_size; i++) {
 171                 if (dfc->freq_table[i] == freq)
 172                         return i;
 173         }
 174
 175         return THERMAL_CSTATE_INVALID;
 176 }
 177
 178 static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
 179 {
 180         struct device *dev = df->dev.parent;
 181         unsigned long voltage;
 182         struct dev_pm_opp *opp;
 183
 184         opp = dev_pm_opp_find_freq_exact(dev, freq, true);
 185         if (PTR_ERR(opp) == -ERANGE)
 186                 opp = dev_pm_opp_find_freq_exact(dev, freq, false);
 187
 188         if (IS_ERR(opp)) {
 189                 dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
 190                                     freq, PTR_ERR(opp));
 191                 return 0;
 192         }
 193
 194         voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
 195         dev_pm_opp_put(opp);
 196
 197         if (voltage == 0) {
 198                 dev_err_ratelimited(dev,
 199                                     "Failed to get voltage for frequency %lu\n",
 200                                     freq);
 201         }
 202
 203         return voltage;
 204 }
 205
 206 /**
 207  * get_static_power() - calculate the static power
 208  * @dfc:        Pointer to devfreq cooling device
 209  * @freq:       Frequency in Hz
 210  *
 211  * Calculate the static power in milliwatts using the supplied
 212  * get_static_power().  The current voltage is calculated using the
 213  * OPP library.  If no get_static_power() was supplied, assume the
 214  * static power is negligible.
 215  */
 216 static unsigned long
 217 get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
 218 {
 219         struct devfreq *df = dfc->devfreq;
 220         unsigned long voltage;
 221
 222         if (!dfc->power_ops->get_static_power)
 223                 return 0;
 224
 225         voltage = get_voltage(df, freq);
 226
 227         if (voltage == 0)
 228                 return 0;
 229
 230         return dfc->power_ops->get_static_power(df, voltage);
 231 }
 232
 233 /**
 234  * get_dynamic_power - calculate the dynamic power
 235  * @dfc:        Pointer to devfreq cooling device
 236  * @freq:       Frequency in Hz
 237  * @voltage:    Voltage in millivolts
 238  *
 239  * Calculate the dynamic power in milliwatts consumed by the device at
 240  * frequency @freq and voltage @voltage.  If the get_dynamic_power()
 241  * was supplied as part of the devfreq_cooling_power struct, then that
 242  * function is used.  Otherwise, a simple power model (Pdyn = Coeff *
 243  * Voltage^2 * Frequency) is used.
 244  */
 245 static unsigned long
 246 get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,
 247                   unsigned long voltage)
 248 {
 249         u64 power;
 250         u32 freq_mhz;
 251         struct devfreq_cooling_power *dfc_power = dfc->power_ops;
 252
 253         if (dfc_power->get_dynamic_power)
 254                 return dfc_power->get_dynamic_power(dfc->devfreq, freq,
 255                                                     voltage);
 256
 257         freq_mhz = freq / 1000000;
 258         power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
 259         do_div(power, 1000000000);
 260
 261         return power;
 262 }
 263
 264
 265 static inline unsigned long get_total_power(struct devfreq_cooling_device *dfc,
 266                                             unsigned long freq,
 267                                             unsigned long voltage)
 268 {
 269         return get_static_power(dfc, freq) + get_dynamic_power(dfc, freq,
 270                                                                voltage);
 271 }
 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         unsigned long voltage;
 284         u32 dyn_power = 0;
 285         u32 static_power = 0;
 286         int res;
 287
 288         state = freq_get_state(dfc, freq);
 289         if (state == THERMAL_CSTATE_INVALID) {
 290                 res = -EAGAIN;
 291                 goto fail;
 292         }
 293
 294         if (dfc->power_ops->get_real_power) {
 295                 voltage = get_voltage(df, freq);
 296                 if (voltage == 0) {
 297                         res = -EINVAL;
 298                         goto fail;
 299                 }
 300
 301                 res = dfc->power_ops->get_real_power(df, power, freq, voltage);
 302                 if (!res) {
 303                         state = dfc->capped_state;
 304                         dfc->res_util = dfc->power_table[state];
 305                         dfc->res_util *= SCALE_ERROR_MITIGATION;
 306
 307                         if (*power > 1)
 308                                 dfc->res_util /= *power;
 309                 } else {
 310                         goto fail;
 311                 }
 312         } else {
 313                 dyn_power = dfc->power_table[state];
 314
 315                 /* Scale dynamic power for utilization */
 316                 dyn_power *= status->busy_time;
 317                 dyn_power /= status->total_time;
 318                 /* Get static power */
 319                 static_power = get_static_power(dfc, freq);
 320
 321                 *power = dyn_power + static_power;
 322         }
 323
 324         trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power,
 325                                               static_power, *power);
 326
 327         return 0;
 328 fail:
 329         /* It is safe to set max in this case */
 330         dfc->res_util = SCALE_ERROR_MITIGATION;
 331         return res;
 332 }
 333
 334 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
 335                                        struct thermal_zone_device *tz,
 336                                        unsigned long state,
 337                                        u32 *power)
 338 {
 339         struct devfreq_cooling_device *dfc = cdev->devdata;
 340         unsigned long freq;
 341         u32 static_power;
 342
 343         if (state >= dfc->freq_table_size)
 344                 return -EINVAL;
 345
 346         freq = dfc->freq_table[state];
 347         static_power = get_static_power(dfc, freq);
 348
 349         *power = dfc->power_table[state] + static_power;
 350         return 0;
 351 }
 352
 353 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
 354                                        struct thermal_zone_device *tz,
 355                                        u32 power, unsigned long *state)
 356 {
 357         struct devfreq_cooling_device *dfc = cdev->devdata;
 358         struct devfreq *df = dfc->devfreq;
 359         struct devfreq_dev_status *status = &df->last_status;
 360         unsigned long freq = status->current_frequency;
 361         unsigned long busy_time;
 362         s32 dyn_power;
 363         u32 static_power;
 364         s32 est_power;
 365         int i;
 366
 367         if (dfc->power_ops->get_real_power) {
 368                 /* Scale for resource utilization */
 369                 est_power = power * dfc->res_util;
 370                 est_power /= SCALE_ERROR_MITIGATION;
 371         } else {
 372                 static_power = get_static_power(dfc, freq);
 373
 374                 dyn_power = power - static_power;
 375                 dyn_power = dyn_power > 0 ? dyn_power : 0;
 376
 377                 /* Scale dynamic power for utilization */
 378                 busy_time = status->busy_time ?: 1;
 379                 est_power = (dyn_power * status->total_time) / busy_time;
 380         }
 381
 382         /*
 383          * Find the first cooling state that is within the power
 384          * budget for dynamic power.
 385          */
 386         for (i = 0; i < dfc->freq_table_size - 1; i++)
 387                 if (est_power >= dfc->power_table[i])
 388                         break;
 389
 390         *state = i;
 391         dfc->capped_state = i;
 392         trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
 393         return 0;
 394 }
 395
 396 static struct thermal_cooling_device_ops devfreq_cooling_ops = {
 397         .get_max_state = devfreq_cooling_get_max_state,
 398         .get_cur_state = devfreq_cooling_get_cur_state,
 399         .set_cur_state = devfreq_cooling_set_cur_state,
 400 };
 401
 402 /**
 403  * devfreq_cooling_gen_tables() - Generate power and freq tables.
 404  * @dfc: Pointer to devfreq cooling device.
 405  *
 406  * Generate power and frequency tables: the power table hold the
 407  * device's maximum power usage at each cooling state (OPP).  The
 408  * static and dynamic power using the appropriate voltage and
 409  * frequency for the state, is acquired from the struct
 410  * devfreq_cooling_power, and summed to make the maximum power draw.
 411  *
 412  * The frequency table holds the frequencies in descending order.
 413  * That way its indexed by cooling device state.
 414  *
 415  * The tables are malloced, and pointers put in dfc.  They must be
 416  * freed when unregistering the devfreq cooling device.
 417  *
 418  * Return: 0 on success, negative error code on failure.
 419  */
 420 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc)
 421 {
 422         struct devfreq *df = dfc->devfreq;
 423         struct device *dev = df->dev.parent;
 424         int ret, num_opps;
 425         unsigned long freq;
 426         u32 *power_table = NULL;
 427         u32 *freq_table;
 428         int i;
 429
 430         num_opps = dev_pm_opp_get_opp_count(dev);
 431
 432         if (dfc->power_ops) {
 433                 power_table = kcalloc(num_opps, sizeof(*power_table),
 434                                       GFP_KERNEL);
 435                 if (!power_table)
 436                         return -ENOMEM;
 437         }
 438
 439         freq_table = kcalloc(num_opps, sizeof(*freq_table),
 440                              GFP_KERNEL);
 441         if (!freq_table) {
 442                 ret = -ENOMEM;
 443                 goto free_power_table;
 444         }
 445
 446         for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
 447                 unsigned long power, voltage;
 448                 struct dev_pm_opp *opp;
 449
 450                 opp = dev_pm_opp_find_freq_floor(dev, &freq);
 451                 if (IS_ERR(opp)) {
 452                         ret = PTR_ERR(opp);
 453                         goto free_tables;
 454                 }
 455
 456                 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
 457                 dev_pm_opp_put(opp);
 458
 459                 if (dfc->power_ops) {
 460                         if (dfc->power_ops->get_real_power)
 461                                 power = get_total_power(dfc, freq, voltage);
 462                         else
 463                                 power = get_dynamic_power(dfc, freq, voltage);
 464
 465                         dev_dbg(dev, "Power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
 466                                 freq / 1000000, voltage, power, power);
 467
 468                         power_table[i] = power;
 469                 }
 470
 471                 freq_table[i] = freq;
 472         }
 473
 474         if (dfc->power_ops)
 475                 dfc->power_table = power_table;
 476
 477         dfc->freq_table = freq_table;
 478         dfc->freq_table_size = num_opps;
 479
 480         return 0;
 481
 482 free_tables:
 483         kfree(freq_table);
 484 free_power_table:
 485         kfree(power_table);
 486
 487         return ret;
 488 }
 489
 490 /**
 491  * of_devfreq_cooling_register_power() - Register devfreq cooling device,
 492  *                                      with OF and power information.
 493  * @np: Pointer to OF device_node.
 494  * @df: Pointer to devfreq device.
 495  * @dfc_power:  Pointer to devfreq_cooling_power.
 496  *
 497  * Register a devfreq cooling device.  The available OPPs must be
 498  * registered on the device.
 499  *
 500  * If @dfc_power is provided, the cooling device is registered with the
 501  * power extensions.  For the power extensions to work correctly,
 502  * devfreq should use the simple_ondemand governor, other governors
 503  * are not currently supported.
 504  */
 505 struct thermal_cooling_device *
 506 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
 507                                   struct devfreq_cooling_power *dfc_power)
 508 {
 509         struct thermal_cooling_device *cdev;
 510         struct devfreq_cooling_device *dfc;
 511         char dev_name[THERMAL_NAME_LENGTH];
 512         int err;
 513
 514         dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
 515         if (!dfc)
 516                 return ERR_PTR(-ENOMEM);
 517
 518         dfc->devfreq = df;
 519
 520         if (dfc_power) {
 521                 dfc->power_ops = dfc_power;
 522
 523                 devfreq_cooling_ops.get_requested_power =
 524                         devfreq_cooling_get_requested_power;
 525                 devfreq_cooling_ops.state2power = devfreq_cooling_state2power;
 526                 devfreq_cooling_ops.power2state = devfreq_cooling_power2state;
 527         }
 528
 529         err = devfreq_cooling_gen_tables(dfc);
 530         if (err)
 531                 goto free_dfc;
 532
 533         err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
 534         if (err < 0)
 535                 goto free_tables;
 536         dfc->id = err;
 537
 538         snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);
 539
 540         cdev = thermal_of_cooling_device_register(np, dev_name, dfc,
 541                                                   &devfreq_cooling_ops);
 542         if (IS_ERR(cdev)) {
 543                 err = PTR_ERR(cdev);
 544                 dev_err(df->dev.parent,
 545                         "Failed to register devfreq cooling device (%d)\n",
 546                         err);
 547                 goto release_ida;
 548         }
 549
 550         dfc->cdev = cdev;
 551
 552         return cdev;
 553
 554 release_ida:
 555         ida_simple_remove(&devfreq_ida, dfc->id);
 556 free_tables:
 557         kfree(dfc->power_table);
 558         kfree(dfc->freq_table);
 559 free_dfc:
 560         kfree(dfc);
 561
 562         return ERR_PTR(err);
 563 }
 564 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
 565
 566 /**
 567  * of_devfreq_cooling_register() - Register devfreq cooling device,
 568  *                                with OF information.
 569  * @np: Pointer to OF device_node.
 570  * @df: Pointer to devfreq device.
 571  */
 572 struct thermal_cooling_device *
 573 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
 574 {
 575         return of_devfreq_cooling_register_power(np, df, NULL);
 576 }
 577 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
 578
 579 /**
 580  * devfreq_cooling_register() - Register devfreq cooling device.
 581  * @df: Pointer to devfreq device.
 582  */
 583 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
 584 {
 585         return of_devfreq_cooling_register(NULL, df);
 586 }
 587 EXPORT_SYMBOL_GPL(devfreq_cooling_register);
 588
 589 /**
 590  * devfreq_cooling_unregister() - Unregister devfreq cooling device.
 591  * @cdev: Pointer to devfreq cooling device to unregister.
 592  */
 593 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
 594 {
 595         struct devfreq_cooling_device *dfc;
 596
 597         if (!cdev)
 598                 return;
 599
 600         dfc = cdev->devdata;
 601
 602         thermal_cooling_device_unregister(dfc->cdev);
 603         ida_simple_remove(&devfreq_ida, dfc->id);
 604         kfree(dfc->power_table);
 605         kfree(dfc->freq_table);
 606
 607         kfree(dfc);
 608 }
 609 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);