drivers/thermal/devfreq_cooling.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * devfreq_cooling: Thermal cooling device implementation for devices using
   4  *                  devfreq
   5  *
   6  * Copyright (C) 2014-2015 ARM Limited
   7  *
   8  * TODO:
   9  *    - If OPPs are added or removed after devfreq cooling has
  10  *      registered, the devfreq cooling won't react to it.
  11  */
  12
  13 #include <linux/devfreq.h>
  14 #include <linux/devfreq_cooling.h>
  15 #include <linux/energy_model.h>
  16 #include <linux/export.h>
  17 #include <linux/slab.h>
  18 #include <linux/pm_opp.h>
  19 #include <linux/pm_qos.h>
  20 #include <linux/thermal.h>
  21 #include <linux/units.h>
  22
  23 #include <trace/events/thermal.h>
  24
  25 #define SCALE_ERROR_MITIGATION  100
  26
  27 /**
  28  * struct devfreq_cooling_device - Devfreq cooling device
  29  *              devfreq_cooling_device registered.
  30  * @cdev:       Pointer to associated thermal cooling device.
  31  * @cooling_ops: devfreq callbacks to thermal cooling device ops
  32  * @devfreq:    Pointer to associated devfreq device.
  33  * @cooling_state:      Current cooling state.
  34  * @freq_table: Pointer to a table with the frequencies sorted in descending
  35  *              order.  You can index the table by cooling device state
  36  * @max_state:  It is the last index, that is, one less than the number of the
  37  *              OPPs
  38  * @power_ops:  Pointer to devfreq_cooling_power, a more precised model.
  39  * @res_util:   Resource utilization scaling factor for the power.
  40  *              It is multiplied by 100 to minimize the error. It is used
  41  *              for estimation of the power budget instead of using
  42  *              'utilization' (which is 'busy_time' / 'total_time').
  43  *              The 'res_util' range is from 100 to power * 100 for the
  44  *              corresponding 'state'.
  45  * @capped_state:       index to cooling state with in dynamic power budget
  46  * @req_max_freq:       PM QoS request for limiting the maximum frequency
  47  *                      of the devfreq device.
  48  * @em_pd:              Energy Model for the associated Devfreq device
  49  */
  50 struct devfreq_cooling_device {
  51         struct thermal_cooling_device *cdev;
  52         struct thermal_cooling_device_ops cooling_ops;
  53         struct devfreq *devfreq;
  54         unsigned long cooling_state;
  55         u32 *freq_table;
  56         size_t max_state;
  57         struct devfreq_cooling_power *power_ops;
  58         u32 res_util;
  59         int capped_state;
  60         struct dev_pm_qos_request req_max_freq;
  61         struct em_perf_domain *em_pd;
  62 };
  63
  64 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
  65                                          unsigned long *state)
  66 {
  67         struct devfreq_cooling_device *dfc = cdev->devdata;
  68
  69         *state = dfc->max_state;
  70
  71         return 0;
  72 }
  73
  74 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
  75                                          unsigned long *state)
  76 {
  77         struct devfreq_cooling_device *dfc = cdev->devdata;
  78
  79         *state = dfc->cooling_state;
  80
  81         return 0;
  82 }
  83
  84 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
  85                                          unsigned long state)
  86 {
  87         struct devfreq_cooling_device *dfc = cdev->devdata;
  88         struct devfreq *df = dfc->devfreq;
  89         struct device *dev = df->dev.parent;
  90         unsigned long freq;
  91         int perf_idx;
  92
  93         if (state == dfc->cooling_state)
  94                 return 0;
  95
  96         dev_dbg(dev, "Setting cooling state %lu\n", state);
  97
  98         if (state > dfc->max_state)
  99                 return -EINVAL;
 100
 101         if (dfc->em_pd) {
 102                 perf_idx = dfc->max_state - state;
 103                 freq = dfc->em_pd->table[perf_idx].frequency * 1000;
 104         } else {
 105                 freq = dfc->freq_table[state];
 106         }
 107
 108         dev_pm_qos_update_request(&dfc->req_max_freq,
 109                                   DIV_ROUND_UP(freq, HZ_PER_KHZ));
 110
 111         dfc->cooling_state = state;
 112
 113         return 0;
 114 }
 115
 116 /**
 117  * get_perf_idx() - get the performance index corresponding to a frequency
 118  * @em_pd:      Pointer to device's Energy Model
 119  * @freq:       frequency in kHz
 120  *
 121  * Return: the performance index associated with the @freq, or
 122  * -EINVAL if it wasn't found.
 123  */
 124 static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
 125 {
 126         int i;
 127
 128         for (i = 0; i < em_pd->nr_perf_states; i++) {
 129                 if (em_pd->table[i].frequency == freq)
 130                         return i;
 131         }
 132
 133         return -EINVAL;
 134 }
 135
 136 static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
 137 {
 138         struct device *dev = df->dev.parent;
 139         unsigned long voltage;
 140         struct dev_pm_opp *opp;
 141
 142         opp = dev_pm_opp_find_freq_exact(dev, freq, true);
 143         if (PTR_ERR(opp) == -ERANGE)
 144                 opp = dev_pm_opp_find_freq_exact(dev, freq, false);
 145
 146         if (IS_ERR(opp)) {
 147                 dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
 148                                     freq, PTR_ERR(opp));
 149                 return 0;
 150         }
 151
 152         voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
 153         dev_pm_opp_put(opp);
 154
 155         if (voltage == 0) {
 156                 dev_err_ratelimited(dev,
 157                                     "Failed to get voltage for frequency %lu\n",
 158                                     freq);
 159         }
 160
 161         return voltage;
 162 }
 163
 164 static void _normalize_load(struct devfreq_dev_status *status)
 165 {
 166         if (status->total_time > 0xfffff) {
 167                 status->total_time >>= 10;
 168                 status->busy_time >>= 10;
 169         }
 170
 171         status->busy_time <<= 10;
 172         status->busy_time /= status->total_time ? : 1;
 173
 174         status->busy_time = status->busy_time ? : 1;
 175         status->total_time = 1024;
 176 }
 177
 178 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
 179                                                u32 *power)
 180 {
 181         struct devfreq_cooling_device *dfc = cdev->devdata;
 182         struct devfreq *df = dfc->devfreq;
 183         struct devfreq_dev_status status;
 184         unsigned long state;
 185         unsigned long freq;
 186         unsigned long voltage;
 187         int res, perf_idx;
 188
 189         mutex_lock(&df->lock);
 190         status = df->last_status;
 191         mutex_unlock(&df->lock);
 192
 193         freq = status.current_frequency;
 194
 195         if (dfc->power_ops && dfc->power_ops->get_real_power) {
 196                 voltage = get_voltage(df, freq);
 197                 if (voltage == 0) {
 198                         res = -EINVAL;
 199                         goto fail;
 200                 }
 201
 202                 res = dfc->power_ops->get_real_power(df, power, freq, voltage);
 203                 if (!res) {
 204                         state = dfc->capped_state;
 205
 206                         /* Convert EM power into milli-Watts first */
 207                         dfc->res_util = dfc->em_pd->table[state].power;
 208                         dfc->res_util /= MICROWATT_PER_MILLIWATT;
 209
 210                         dfc->res_util *= SCALE_ERROR_MITIGATION;
 211
 212                         if (*power > 1)
 213                                 dfc->res_util /= *power;
 214                 } else {
 215                         goto fail;
 216                 }
 217         } else {
 218                 /* Energy Model frequencies are in kHz */
 219                 perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
 220                 if (perf_idx < 0) {
 221                         res = -EAGAIN;
 222                         goto fail;
 223                 }
 224
 225                 _normalize_load(&status);
 226
 227                 /* Convert EM power into milli-Watts first */
 228                 *power = dfc->em_pd->table[perf_idx].power;
 229                 *power /= MICROWATT_PER_MILLIWATT;
 230                 /* Scale power for utilization */
 231                 *power *= status.busy_time;
 232                 *power >>= 10;
 233         }
 234
 235         trace_thermal_power_devfreq_get_power(cdev, &status, freq, *power);
 236
 237         return 0;
 238 fail:
 239         /* It is safe to set max in this case */
 240         dfc->res_util = SCALE_ERROR_MITIGATION;
 241         return res;
 242 }
 243
 244 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
 245                                        unsigned long state, u32 *power)
 246 {
 247         struct devfreq_cooling_device *dfc = cdev->devdata;
 248         int perf_idx;
 249
 250         if (state > dfc->max_state)
 251                 return -EINVAL;
 252
 253         perf_idx = dfc->max_state - state;
 254         *power = dfc->em_pd->table[perf_idx].power;
 255         *power /= MICROWATT_PER_MILLIWATT;
 256
 257         return 0;
 258 }
 259
 260 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
 261                                        u32 power, unsigned long *state)
 262 {
 263         struct devfreq_cooling_device *dfc = cdev->devdata;
 264         struct devfreq *df = dfc->devfreq;
 265         struct devfreq_dev_status status;
 266         unsigned long freq, em_power_mw;
 267         s32 est_power;
 268         int i;
 269
 270         mutex_lock(&df->lock);
 271         status = df->last_status;
 272         mutex_unlock(&df->lock);
 273
 274         freq = status.current_frequency;
 275
 276         if (dfc->power_ops && dfc->power_ops->get_real_power) {
 277                 /* Scale for resource utilization */
 278                 est_power = power * dfc->res_util;
 279                 est_power /= SCALE_ERROR_MITIGATION;
 280         } else {
 281                 /* Scale dynamic power for utilization */
 282                 _normalize_load(&status);
 283                 est_power = power << 10;
 284                 est_power /= status.busy_time;
 285         }
 286
 287         /*
 288          * Find the first cooling state that is within the power
 289          * budget. The EM power table is sorted ascending.
 290          */
 291         for (i = dfc->max_state; i > 0; i--) {
 292                 /* Convert EM power to milli-Watts to make safe comparison */
 293                 em_power_mw = dfc->em_pd->table[i].power;
 294                 em_power_mw /= MICROWATT_PER_MILLIWATT;
 295                 if (est_power >= em_power_mw)
 296                         break;
 297         }
 298
 299         *state = dfc->max_state - i;
 300         dfc->capped_state = *state;
 301
 302         trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
 303         return 0;
 304 }
 305
 306 /**
 307  * devfreq_cooling_gen_tables() - Generate frequency table.
 308  * @dfc:        Pointer to devfreq cooling device.
 309  * @num_opps:   Number of OPPs
 310  *
 311  * Generate frequency table which holds the frequencies in descending
 312  * order. That way its indexed by cooling device state. This is for
 313  * compatibility with drivers which do not register Energy Model.
 314  *
 315  * Return: 0 on success, negative error code on failure.
 316  */
 317 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
 318                                       int num_opps)
 319 {
 320         struct devfreq *df = dfc->devfreq;
 321         struct device *dev = df->dev.parent;
 322         unsigned long freq;
 323         int i;
 324
 325         dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
 326                              GFP_KERNEL);
 327         if (!dfc->freq_table)
 328                 return -ENOMEM;
 329
 330         for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
 331                 struct dev_pm_opp *opp;
 332
 333                 opp = dev_pm_opp_find_freq_floor(dev, &freq);
 334                 if (IS_ERR(opp)) {
 335                         kfree(dfc->freq_table);
 336                         return PTR_ERR(opp);
 337                 }
 338
 339                 dev_pm_opp_put(opp);
 340                 dfc->freq_table[i] = freq;
 341         }
 342
 343         return 0;
 344 }
 345
 346 /**
 347  * of_devfreq_cooling_register_power() - Register devfreq cooling device,
 348  *                                      with OF and power information.
 349  * @np: Pointer to OF device_node.
 350  * @df: Pointer to devfreq device.
 351  * @dfc_power:  Pointer to devfreq_cooling_power.
 352  *
 353  * Register a devfreq cooling device.  The available OPPs must be
 354  * registered on the device.
 355  *
 356  * If @dfc_power is provided, the cooling device is registered with the
 357  * power extensions.  For the power extensions to work correctly,
 358  * devfreq should use the simple_ondemand governor, other governors
 359  * are not currently supported.
 360  */
 361 struct thermal_cooling_device *
 362 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
 363                                   struct devfreq_cooling_power *dfc_power)
 364 {
 365         struct thermal_cooling_device *cdev;
 366         struct device *dev = df->dev.parent;
 367         struct devfreq_cooling_device *dfc;
 368         struct em_perf_domain *em;
 369         struct thermal_cooling_device_ops *ops;
 370         char *name;
 371         int err, num_opps;
 372
 373
 374         dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
 375         if (!dfc)
 376                 return ERR_PTR(-ENOMEM);
 377
 378         dfc->devfreq = df;
 379
 380         ops = &dfc->cooling_ops;
 381         ops->get_max_state = devfreq_cooling_get_max_state;
 382         ops->get_cur_state = devfreq_cooling_get_cur_state;
 383         ops->set_cur_state = devfreq_cooling_set_cur_state;
 384
 385         em = em_pd_get(dev);
 386         if (em && !em_is_artificial(em)) {
 387                 dfc->em_pd = em;
 388                 ops->get_requested_power =
 389                         devfreq_cooling_get_requested_power;
 390                 ops->state2power = devfreq_cooling_state2power;
 391                 ops->power2state = devfreq_cooling_power2state;
 392
 393                 dfc->power_ops = dfc_power;
 394
 395                 num_opps = em_pd_nr_perf_states(dfc->em_pd);
 396         } else {
 397                 /* Backward compatibility for drivers which do not use IPA */
 398                 dev_dbg(dev, "missing proper EM for cooling device\n");
 399
 400                 num_opps = dev_pm_opp_get_opp_count(dev);
 401
 402                 err = devfreq_cooling_gen_tables(dfc, num_opps);
 403                 if (err)
 404                         goto free_dfc;
 405         }
 406
 407         if (num_opps <= 0) {
 408                 err = -EINVAL;
 409                 goto free_dfc;
 410         }
 411
 412         /* max_state is an index, not a counter */
 413         dfc->max_state = num_opps - 1;
 414
 415         err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
 416                                      DEV_PM_QOS_MAX_FREQUENCY,
 417                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 418         if (err < 0)
 419                 goto free_table;
 420
 421         err = -ENOMEM;
 422         name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
 423         if (!name)
 424                 goto remove_qos_req;
 425
 426         cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
 427         kfree(name);
 428
 429         if (IS_ERR(cdev)) {
 430                 err = PTR_ERR(cdev);
 431                 dev_err(dev,
 432                         "Failed to register devfreq cooling device (%d)\n",
 433                         err);
 434                 goto remove_qos_req;
 435         }
 436
 437         dfc->cdev = cdev;
 438
 439         return cdev;
 440
 441 remove_qos_req:
 442         dev_pm_qos_remove_request(&dfc->req_max_freq);
 443 free_table:
 444         kfree(dfc->freq_table);
 445 free_dfc:
 446         kfree(dfc);
 447
 448         return ERR_PTR(err);
 449 }
 450 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
 451
 452 /**
 453  * of_devfreq_cooling_register() - Register devfreq cooling device,
 454  *                                with OF information.
 455  * @np: Pointer to OF device_node.
 456  * @df: Pointer to devfreq device.
 457  */
 458 struct thermal_cooling_device *
 459 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
 460 {
 461         return of_devfreq_cooling_register_power(np, df, NULL);
 462 }
 463 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
 464
 465 /**
 466  * devfreq_cooling_register() - Register devfreq cooling device.
 467  * @df: Pointer to devfreq device.
 468  */
 469 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
 470 {
 471         return of_devfreq_cooling_register(NULL, df);
 472 }
 473 EXPORT_SYMBOL_GPL(devfreq_cooling_register);
 474
 475 /**
 476  * devfreq_cooling_em_register() - Register devfreq cooling device with
 477  *              power information and automatically register Energy Model (EM)
 478  * @df:         Pointer to devfreq device.
 479  * @dfc_power:  Pointer to devfreq_cooling_power.
 480  *
 481  * Register a devfreq cooling device and automatically register EM. The
 482  * available OPPs must be registered for the device.
 483  *
 484  * If @dfc_power is provided, the cooling device is registered with the
 485  * power extensions. It is using the simple Energy Model which requires
 486  * "dynamic-power-coefficient" a devicetree property. To not break drivers
 487  * which miss that DT property, the function won't bail out when the EM
 488  * registration failed. The cooling device will be registered if everything
 489  * else is OK.
 490  */
 491 struct thermal_cooling_device *
 492 devfreq_cooling_em_register(struct devfreq *df,
 493                             struct devfreq_cooling_power *dfc_power)
 494 {
 495         struct thermal_cooling_device *cdev;
 496         struct device *dev;
 497         int ret;
 498
 499         if (IS_ERR_OR_NULL(df))
 500                 return ERR_PTR(-EINVAL);
 501
 502         dev = df->dev.parent;
 503
 504         ret = dev_pm_opp_of_register_em(dev, NULL);
 505         if (ret)
 506                 dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
 507                         ret);
 508
 509         cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);
 510
 511         if (IS_ERR_OR_NULL(cdev))
 512                 em_dev_unregister_perf_domain(dev);
 513
 514         return cdev;
 515 }
 516 EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
 517
 518 /**
 519  * devfreq_cooling_unregister() - Unregister devfreq cooling device.
 520  * @cdev: Pointer to devfreq cooling device to unregister.
 521  *
 522  * Unregisters devfreq cooling device and related Energy Model if it was
 523  * present.
 524  */
 525 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
 526 {
 527         struct devfreq_cooling_device *dfc;
 528         struct device *dev;
 529
 530         if (IS_ERR_OR_NULL(cdev))
 531                 return;
 532
 533         dfc = cdev->devdata;
 534         dev = dfc->devfreq->dev.parent;
 535
 536         thermal_cooling_device_unregister(dfc->cdev);
 537         dev_pm_qos_remove_request(&dfc->req_max_freq);
 538
 539         em_dev_unregister_perf_domain(dev);
 540
 541         kfree(dfc->freq_table);
 542         kfree(dfc);
 543 }
 544 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);