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