drivers/devfreq/devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   4  *          for Non-CPU Devices.
   5  *
   6  * Copyright (C) 2011 Samsung Electronics
   7  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/kmod.h>
  12 #include <linux/sched.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/errno.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/export.h>
  18 #include <linux/slab.h>
  19 #include <linux/stat.h>
  20 #include <linux/pm_opp.h>
  21 #include <linux/devfreq.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/list.h>
  25 #include <linux/printk.h>
  26 #include <linux/hrtimer.h>
  27 #include <linux/of.h>
  28 #include <linux/pm_qos.h>
  29 #include "governor.h"
  30
  31 #define CREATE_TRACE_POINTS
  32 #include <trace/events/devfreq.h>
  33
  34 #define HZ_PER_KHZ      1000
  35
  36 static struct class *devfreq_class;
  37 static struct dentry *devfreq_debugfs;
  38
  39 /*
  40  * devfreq core provides delayed work based load monitoring helper
  41  * functions. Governors can use these or can implement their own
  42  * monitoring mechanism.
  43  */
  44 static struct workqueue_struct *devfreq_wq;
  45
  46 /* The list of all device-devfreq governors */
  47 static LIST_HEAD(devfreq_governor_list);
  48 /* The list of all device-devfreq */
  49 static LIST_HEAD(devfreq_list);
  50 static DEFINE_MUTEX(devfreq_list_lock);
  51
  52 /**
  53  * find_device_devfreq() - find devfreq struct using device pointer
  54  * @dev:        device pointer used to lookup device devfreq.
  55  *
  56  * Search the list of device devfreqs and return the matched device's
  57  * devfreq info. devfreq_list_lock should be held by the caller.
  58  */
  59 static struct devfreq *find_device_devfreq(struct device *dev)
  60 {
  61         struct devfreq *tmp_devfreq;
  62
  63         if (IS_ERR_OR_NULL(dev)) {
  64                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  65                 return ERR_PTR(-EINVAL);
  66         }
  67         WARN(!mutex_is_locked(&devfreq_list_lock),
  68              "devfreq_list_lock must be locked.");
  69
  70         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  71                 if (tmp_devfreq->dev.parent == dev)
  72                         return tmp_devfreq;
  73         }
  74
  75         return ERR_PTR(-ENODEV);
  76 }
  77
  78 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  79 {
  80         struct dev_pm_opp *opp;
  81         unsigned long min_freq = 0;
  82
  83         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  84         if (IS_ERR(opp))
  85                 min_freq = 0;
  86         else
  87                 dev_pm_opp_put(opp);
  88
  89         return min_freq;
  90 }
  91
  92 static unsigned long find_available_max_freq(struct devfreq *devfreq)
  93 {
  94         struct dev_pm_opp *opp;
  95         unsigned long max_freq = ULONG_MAX;
  96
  97         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
  98         if (IS_ERR(opp))
  99                 max_freq = 0;
 100         else
 101                 dev_pm_opp_put(opp);
 102
 103         return max_freq;
 104 }
 105
 106 /**
 107  * get_freq_range() - Get the current freq range
 108  * @devfreq:    the devfreq instance
 109  * @min_freq:   the min frequency
 110  * @max_freq:   the max frequency
 111  *
 112  * This takes into consideration all constraints.
 113  */
 114 static void get_freq_range(struct devfreq *devfreq,
 115                            unsigned long *min_freq,
 116                            unsigned long *max_freq)
 117 {
 118         unsigned long *freq_table = devfreq->profile->freq_table;
 119         s32 qos_min_freq, qos_max_freq;
 120
 121         lockdep_assert_held(&devfreq->lock);
 122
 123         /*
 124          * Initialize minimum/maximum frequency from freq table.
 125          * The devfreq drivers can initialize this in either ascending or
 126          * descending order and devfreq core supports both.
 127          */
 128         if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
 129                 *min_freq = freq_table[0];
 130                 *max_freq = freq_table[devfreq->profile->max_state - 1];
 131         } else {
 132                 *min_freq = freq_table[devfreq->profile->max_state - 1];
 133                 *max_freq = freq_table[0];
 134         }
 135
 136         /* Apply constraints from PM QoS */
 137         qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 138                                              DEV_PM_QOS_MIN_FREQUENCY);
 139         qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 140                                              DEV_PM_QOS_MAX_FREQUENCY);
 141         *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 142         if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 143                 *max_freq = min(*max_freq,
 144                                 (unsigned long)HZ_PER_KHZ * qos_max_freq);
 145
 146         /* Apply constraints from OPP interface */
 147         *min_freq = max(*min_freq, devfreq->scaling_min_freq);
 148         *max_freq = min(*max_freq, devfreq->scaling_max_freq);
 149
 150         if (*min_freq > *max_freq)
 151                 *min_freq = *max_freq;
 152 }
 153
 154 /**
 155  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 156  * @devfreq:    the devfreq instance
 157  * @freq:       the target frequency
 158  */
 159 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 160 {
 161         int lev;
 162
 163         for (lev = 0; lev < devfreq->profile->max_state; lev++)
 164                 if (freq == devfreq->profile->freq_table[lev])
 165                         return lev;
 166
 167         return -EINVAL;
 168 }
 169
 170 static int set_freq_table(struct devfreq *devfreq)
 171 {
 172         struct devfreq_dev_profile *profile = devfreq->profile;
 173         struct dev_pm_opp *opp;
 174         unsigned long freq;
 175         int i, count;
 176
 177         /* Initialize the freq_table from OPP table */
 178         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 179         if (count <= 0)
 180                 return -EINVAL;
 181
 182         profile->max_state = count;
 183         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 184                                         profile->max_state,
 185                                         sizeof(*profile->freq_table),
 186                                         GFP_KERNEL);
 187         if (!profile->freq_table) {
 188                 profile->max_state = 0;
 189                 return -ENOMEM;
 190         }
 191
 192         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 193                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 194                 if (IS_ERR(opp)) {
 195                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 196                         profile->max_state = 0;
 197                         return PTR_ERR(opp);
 198                 }
 199                 dev_pm_opp_put(opp);
 200                 profile->freq_table[i] = freq;
 201         }
 202
 203         return 0;
 204 }
 205
 206 /**
 207  * devfreq_update_status() - Update statistics of devfreq behavior
 208  * @devfreq:    the devfreq instance
 209  * @freq:       the update target frequency
 210  */
 211 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 212 {
 213         int lev, prev_lev, ret = 0;
 214         u64 cur_time;
 215
 216         lockdep_assert_held(&devfreq->lock);
 217         cur_time = get_jiffies_64();
 218
 219         /* Immediately exit if previous_freq is not initialized yet. */
 220         if (!devfreq->previous_freq)
 221                 goto out;
 222
 223         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 224         if (prev_lev < 0) {
 225                 ret = prev_lev;
 226                 goto out;
 227         }
 228
 229         devfreq->stats.time_in_state[prev_lev] +=
 230                         cur_time - devfreq->stats.last_update;
 231
 232         lev = devfreq_get_freq_level(devfreq, freq);
 233         if (lev < 0) {
 234                 ret = lev;
 235                 goto out;
 236         }
 237
 238         if (lev != prev_lev) {
 239                 devfreq->stats.trans_table[
 240                         (prev_lev * devfreq->profile->max_state) + lev]++;
 241                 devfreq->stats.total_trans++;
 242         }
 243
 244 out:
 245         devfreq->stats.last_update = cur_time;
 246         return ret;
 247 }
 248 EXPORT_SYMBOL(devfreq_update_status);
 249
 250 /**
 251  * find_devfreq_governor() - find devfreq governor from name
 252  * @name:       name of the governor
 253  *
 254  * Search the list of devfreq governors and return the matched
 255  * governor's pointer. devfreq_list_lock should be held by the caller.
 256  */
 257 static struct devfreq_governor *find_devfreq_governor(const char *name)
 258 {
 259         struct devfreq_governor *tmp_governor;
 260
 261         if (IS_ERR_OR_NULL(name)) {
 262                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 263                 return ERR_PTR(-EINVAL);
 264         }
 265         WARN(!mutex_is_locked(&devfreq_list_lock),
 266              "devfreq_list_lock must be locked.");
 267
 268         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 269                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 270                         return tmp_governor;
 271         }
 272
 273         return ERR_PTR(-ENODEV);
 274 }
 275
 276 /**
 277  * try_then_request_governor() - Try to find the governor and request the
 278  *                               module if is not found.
 279  * @name:       name of the governor
 280  *
 281  * Search the list of devfreq governors and request the module and try again
 282  * if is not found. This can happen when both drivers (the governor driver
 283  * and the driver that call devfreq_add_device) are built as modules.
 284  * devfreq_list_lock should be held by the caller. Returns the matched
 285  * governor's pointer or an error pointer.
 286  */
 287 static struct devfreq_governor *try_then_request_governor(const char *name)
 288 {
 289         struct devfreq_governor *governor;
 290         int err = 0;
 291
 292         if (IS_ERR_OR_NULL(name)) {
 293                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 294                 return ERR_PTR(-EINVAL);
 295         }
 296         WARN(!mutex_is_locked(&devfreq_list_lock),
 297              "devfreq_list_lock must be locked.");
 298
 299         governor = find_devfreq_governor(name);
 300         if (IS_ERR(governor)) {
 301                 mutex_unlock(&devfreq_list_lock);
 302
 303                 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 304                              DEVFREQ_NAME_LEN))
 305                         err = request_module("governor_%s", "simpleondemand");
 306                 else
 307                         err = request_module("governor_%s", name);
 308                 /* Restore previous state before return */
 309                 mutex_lock(&devfreq_list_lock);
 310                 if (err)
 311                         return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 312
 313                 governor = find_devfreq_governor(name);
 314         }
 315
 316         return governor;
 317 }
 318
 319 static int devfreq_notify_transition(struct devfreq *devfreq,
 320                 struct devfreq_freqs *freqs, unsigned int state)
 321 {
 322         if (!devfreq)
 323                 return -EINVAL;
 324
 325         switch (state) {
 326         case DEVFREQ_PRECHANGE:
 327                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 328                                 DEVFREQ_PRECHANGE, freqs);
 329                 break;
 330
 331         case DEVFREQ_POSTCHANGE:
 332                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 333                                 DEVFREQ_POSTCHANGE, freqs);
 334                 break;
 335         default:
 336                 return -EINVAL;
 337         }
 338
 339         return 0;
 340 }
 341
 342 static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 343                               u32 flags)
 344 {
 345         struct devfreq_freqs freqs;
 346         unsigned long cur_freq;
 347         int err = 0;
 348
 349         if (devfreq->profile->get_cur_freq)
 350                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 351         else
 352                 cur_freq = devfreq->previous_freq;
 353
 354         freqs.old = cur_freq;
 355         freqs.new = new_freq;
 356         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 357
 358         err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 359         if (err) {
 360                 freqs.new = cur_freq;
 361                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 362                 return err;
 363         }
 364
 365         freqs.new = new_freq;
 366         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 367
 368         if (devfreq_update_status(devfreq, new_freq))
 369                 dev_err(&devfreq->dev,
 370                         "Couldn't update frequency transition information.\n");
 371
 372         devfreq->previous_freq = new_freq;
 373
 374         if (devfreq->suspend_freq)
 375                 devfreq->resume_freq = cur_freq;
 376
 377         return err;
 378 }
 379
 380 /* Load monitoring helper functions for governors use */
 381
 382 /**
 383  * update_devfreq() - Reevaluate the device and configure frequency.
 384  * @devfreq:    the devfreq instance.
 385  *
 386  * Note: Lock devfreq->lock before calling update_devfreq
 387  *       This function is exported for governors.
 388  */
 389 int update_devfreq(struct devfreq *devfreq)
 390 {
 391         unsigned long freq, min_freq, max_freq;
 392         int err = 0;
 393         u32 flags = 0;
 394
 395         if (!mutex_is_locked(&devfreq->lock)) {
 396                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 397                 return -EINVAL;
 398         }
 399
 400         if (!devfreq->governor)
 401                 return -EINVAL;
 402
 403         /* Reevaluate the proper frequency */
 404         err = devfreq->governor->get_target_freq(devfreq, &freq);
 405         if (err)
 406                 return err;
 407         get_freq_range(devfreq, &min_freq, &max_freq);
 408
 409         if (freq < min_freq) {
 410                 freq = min_freq;
 411                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 412         }
 413         if (freq > max_freq) {
 414                 freq = max_freq;
 415                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 416         }
 417
 418         return devfreq_set_target(devfreq, freq, flags);
 419
 420 }
 421 EXPORT_SYMBOL(update_devfreq);
 422
 423 /**
 424  * devfreq_monitor() - Periodically poll devfreq objects.
 425  * @work:       the work struct used to run devfreq_monitor periodically.
 426  *
 427  */
 428 static void devfreq_monitor(struct work_struct *work)
 429 {
 430         int err;
 431         struct devfreq *devfreq = container_of(work,
 432                                         struct devfreq, work.work);
 433
 434         mutex_lock(&devfreq->lock);
 435         err = update_devfreq(devfreq);
 436         if (err)
 437                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 438
 439         queue_delayed_work(devfreq_wq, &devfreq->work,
 440                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 441         mutex_unlock(&devfreq->lock);
 442
 443         trace_devfreq_monitor(devfreq);
 444 }
 445
 446 /**
 447  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 448  * @devfreq:    the devfreq instance.
 449  *
 450  * Helper function for starting devfreq device load monitoring. By
 451  * default delayed work based monitoring is supported. Function
 452  * to be called from governor in response to DEVFREQ_GOV_START
 453  * event when device is added to devfreq framework.
 454  */
 455 void devfreq_monitor_start(struct devfreq *devfreq)
 456 {
 457         if (devfreq->governor->interrupt_driven)
 458                 return;
 459
 460         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 461         if (devfreq->profile->polling_ms)
 462                 queue_delayed_work(devfreq_wq, &devfreq->work,
 463                         msecs_to_jiffies(devfreq->profile->polling_ms));
 464 }
 465 EXPORT_SYMBOL(devfreq_monitor_start);
 466
 467 /**
 468  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 469  * @devfreq:    the devfreq instance.
 470  *
 471  * Helper function to stop devfreq device load monitoring. Function
 472  * to be called from governor in response to DEVFREQ_GOV_STOP
 473  * event when device is removed from devfreq framework.
 474  */
 475 void devfreq_monitor_stop(struct devfreq *devfreq)
 476 {
 477         if (devfreq->governor->interrupt_driven)
 478                 return;
 479
 480         cancel_delayed_work_sync(&devfreq->work);
 481 }
 482 EXPORT_SYMBOL(devfreq_monitor_stop);
 483
 484 /**
 485  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 486  * @devfreq:    the devfreq instance.
 487  *
 488  * Helper function to suspend devfreq device load monitoring. Function
 489  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 490  * event or when polling interval is set to zero.
 491  *
 492  * Note: Though this function is same as devfreq_monitor_stop(),
 493  * intentionally kept separate to provide hooks for collecting
 494  * transition statistics.
 495  */
 496 void devfreq_monitor_suspend(struct devfreq *devfreq)
 497 {
 498         mutex_lock(&devfreq->lock);
 499         if (devfreq->stop_polling) {
 500                 mutex_unlock(&devfreq->lock);
 501                 return;
 502         }
 503
 504         devfreq_update_status(devfreq, devfreq->previous_freq);
 505         devfreq->stop_polling = true;
 506         mutex_unlock(&devfreq->lock);
 507
 508         if (devfreq->governor->interrupt_driven)
 509                 return;
 510
 511         cancel_delayed_work_sync(&devfreq->work);
 512 }
 513 EXPORT_SYMBOL(devfreq_monitor_suspend);
 514
 515 /**
 516  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 517  * @devfreq:    the devfreq instance.
 518  *
 519  * Helper function to resume devfreq device load monitoring. Function
 520  * to be called from governor in response to DEVFREQ_GOV_RESUME
 521  * event or when polling interval is set to non-zero.
 522  */
 523 void devfreq_monitor_resume(struct devfreq *devfreq)
 524 {
 525         unsigned long freq;
 526
 527         mutex_lock(&devfreq->lock);
 528         if (!devfreq->stop_polling)
 529                 goto out;
 530
 531         if (devfreq->governor->interrupt_driven)
 532                 goto out_update;
 533
 534         if (!delayed_work_pending(&devfreq->work) &&
 535                         devfreq->profile->polling_ms)
 536                 queue_delayed_work(devfreq_wq, &devfreq->work,
 537                         msecs_to_jiffies(devfreq->profile->polling_ms));
 538
 539 out_update:
 540         devfreq->stats.last_update = get_jiffies_64();
 541         devfreq->stop_polling = false;
 542
 543         if (devfreq->profile->get_cur_freq &&
 544                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 545                 devfreq->previous_freq = freq;
 546
 547 out:
 548         mutex_unlock(&devfreq->lock);
 549 }
 550 EXPORT_SYMBOL(devfreq_monitor_resume);
 551
 552 /**
 553  * devfreq_interval_update() - Update device devfreq monitoring interval
 554  * @devfreq:    the devfreq instance.
 555  * @delay:      new polling interval to be set.
 556  *
 557  * Helper function to set new load monitoring polling interval. Function
 558  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 559  */
 560 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 561 {
 562         unsigned int cur_delay = devfreq->profile->polling_ms;
 563         unsigned int new_delay = *delay;
 564
 565         mutex_lock(&devfreq->lock);
 566         devfreq->profile->polling_ms = new_delay;
 567
 568         if (devfreq->stop_polling)
 569                 goto out;
 570
 571         if (devfreq->governor->interrupt_driven)
 572                 goto out;
 573
 574         /* if new delay is zero, stop polling */
 575         if (!new_delay) {
 576                 mutex_unlock(&devfreq->lock);
 577                 cancel_delayed_work_sync(&devfreq->work);
 578                 return;
 579         }
 580
 581         /* if current delay is zero, start polling with new delay */
 582         if (!cur_delay) {
 583                 queue_delayed_work(devfreq_wq, &devfreq->work,
 584                         msecs_to_jiffies(devfreq->profile->polling_ms));
 585                 goto out;
 586         }
 587
 588         /* if current delay is greater than new delay, restart polling */
 589         if (cur_delay > new_delay) {
 590                 mutex_unlock(&devfreq->lock);
 591                 cancel_delayed_work_sync(&devfreq->work);
 592                 mutex_lock(&devfreq->lock);
 593                 if (!devfreq->stop_polling)
 594                         queue_delayed_work(devfreq_wq, &devfreq->work,
 595                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 596         }
 597 out:
 598         mutex_unlock(&devfreq->lock);
 599 }
 600 EXPORT_SYMBOL(devfreq_interval_update);
 601
 602 /**
 603  * devfreq_notifier_call() - Notify that the device frequency requirements
 604  *                           has been changed out of devfreq framework.
 605  * @nb:         the notifier_block (supposed to be devfreq->nb)
 606  * @type:       not used
 607  * @devp:       not used
 608  *
 609  * Called by a notifier that uses devfreq->nb.
 610  */
 611 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 612                                  void *devp)
 613 {
 614         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 615         int err = -EINVAL;
 616
 617         mutex_lock(&devfreq->lock);
 618
 619         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 620         if (!devfreq->scaling_min_freq)
 621                 goto out;
 622
 623         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 624         if (!devfreq->scaling_max_freq) {
 625                 devfreq->scaling_max_freq = ULONG_MAX;
 626                 goto out;
 627         }
 628
 629         err = update_devfreq(devfreq);
 630
 631 out:
 632         mutex_unlock(&devfreq->lock);
 633         if (err)
 634                 dev_err(devfreq->dev.parent,
 635                         "failed to update frequency from OPP notifier (%d)\n",
 636                         err);
 637
 638         return NOTIFY_OK;
 639 }
 640
 641 /**
 642  * qos_notifier_call() - Common handler for QoS constraints.
 643  * @devfreq:    the devfreq instance.
 644  */
 645 static int qos_notifier_call(struct devfreq *devfreq)
 646 {
 647         int err;
 648
 649         mutex_lock(&devfreq->lock);
 650         err = update_devfreq(devfreq);
 651         mutex_unlock(&devfreq->lock);
 652         if (err)
 653                 dev_err(devfreq->dev.parent,
 654                         "failed to update frequency from PM QoS (%d)\n",
 655                         err);
 656
 657         return NOTIFY_OK;
 658 }
 659
 660 /**
 661  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 662  * @nb:         Should be devfreq->nb_min
 663  */
 664 static int qos_min_notifier_call(struct notifier_block *nb,
 665                                          unsigned long val, void *ptr)
 666 {
 667         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 668 }
 669
 670 /**
 671  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 672  * @nb:         Should be devfreq->nb_max
 673  */
 674 static int qos_max_notifier_call(struct notifier_block *nb,
 675                                          unsigned long val, void *ptr)
 676 {
 677         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 678 }
 679
 680 /**
 681  * devfreq_dev_release() - Callback for struct device to release the device.
 682  * @dev:        the devfreq device
 683  *
 684  * Remove devfreq from the list and release its resources.
 685  */
 686 static void devfreq_dev_release(struct device *dev)
 687 {
 688         struct devfreq *devfreq = to_devfreq(dev);
 689         int err;
 690
 691         mutex_lock(&devfreq_list_lock);
 692         list_del(&devfreq->node);
 693         mutex_unlock(&devfreq_list_lock);
 694
 695         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 696                                          DEV_PM_QOS_MAX_FREQUENCY);
 697         if (err && err != -ENOENT)
 698                 dev_warn(dev->parent,
 699                         "Failed to remove max_freq notifier: %d\n", err);
 700         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 701                                          DEV_PM_QOS_MIN_FREQUENCY);
 702         if (err && err != -ENOENT)
 703                 dev_warn(dev->parent,
 704                         "Failed to remove min_freq notifier: %d\n", err);
 705
 706         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 707                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 708                 if (err)
 709                         dev_warn(dev->parent,
 710                                 "Failed to remove max_freq request: %d\n", err);
 711         }
 712         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 713                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 714                 if (err)
 715                         dev_warn(dev->parent,
 716                                 "Failed to remove min_freq request: %d\n", err);
 717         }
 718
 719         if (devfreq->profile->exit)
 720                 devfreq->profile->exit(devfreq->dev.parent);
 721
 722         mutex_destroy(&devfreq->lock);
 723         kfree(devfreq);
 724 }
 725
 726 /**
 727  * devfreq_add_device() - Add devfreq feature to the device
 728  * @dev:        the device to add devfreq feature.
 729  * @profile:    device-specific profile to run devfreq.
 730  * @governor_name:      name of the policy to choose frequency.
 731  * @data:       private data for the governor. The devfreq framework does not
 732  *              touch this value.
 733  */
 734 struct devfreq *devfreq_add_device(struct device *dev,
 735                                    struct devfreq_dev_profile *profile,
 736                                    const char *governor_name,
 737                                    void *data)
 738 {
 739         struct devfreq *devfreq;
 740         struct devfreq_governor *governor;
 741         int err = 0;
 742
 743         if (!dev || !profile || !governor_name) {
 744                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 745                 return ERR_PTR(-EINVAL);
 746         }
 747
 748         mutex_lock(&devfreq_list_lock);
 749         devfreq = find_device_devfreq(dev);
 750         mutex_unlock(&devfreq_list_lock);
 751         if (!IS_ERR(devfreq)) {
 752                 dev_err(dev, "%s: devfreq device already exists!\n",
 753                         __func__);
 754                 err = -EINVAL;
 755                 goto err_out;
 756         }
 757
 758         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 759         if (!devfreq) {
 760                 err = -ENOMEM;
 761                 goto err_out;
 762         }
 763
 764         mutex_init(&devfreq->lock);
 765         mutex_lock(&devfreq->lock);
 766         devfreq->dev.parent = dev;
 767         devfreq->dev.class = devfreq_class;
 768         devfreq->dev.release = devfreq_dev_release;
 769         INIT_LIST_HEAD(&devfreq->node);
 770         devfreq->profile = profile;
 771         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 772         devfreq->previous_freq = profile->initial_freq;
 773         devfreq->last_status.current_frequency = profile->initial_freq;
 774         devfreq->data = data;
 775         devfreq->nb.notifier_call = devfreq_notifier_call;
 776
 777         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 778                 mutex_unlock(&devfreq->lock);
 779                 err = set_freq_table(devfreq);
 780                 if (err < 0)
 781                         goto err_dev;
 782                 mutex_lock(&devfreq->lock);
 783         }
 784
 785         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 786         if (!devfreq->scaling_min_freq) {
 787                 mutex_unlock(&devfreq->lock);
 788                 err = -EINVAL;
 789                 goto err_dev;
 790         }
 791
 792         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 793         if (!devfreq->scaling_max_freq) {
 794                 mutex_unlock(&devfreq->lock);
 795                 err = -EINVAL;
 796                 goto err_dev;
 797         }
 798
 799         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 800         atomic_set(&devfreq->suspend_count, 0);
 801
 802         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 803         err = device_register(&devfreq->dev);
 804         if (err) {
 805                 mutex_unlock(&devfreq->lock);
 806                 put_device(&devfreq->dev);
 807                 goto err_out;
 808         }
 809
 810         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 811                         array3_size(sizeof(unsigned int),
 812                                     devfreq->profile->max_state,
 813                                     devfreq->profile->max_state),
 814                         GFP_KERNEL);
 815         if (!devfreq->stats.trans_table) {
 816                 mutex_unlock(&devfreq->lock);
 817                 err = -ENOMEM;
 818                 goto err_devfreq;
 819         }
 820
 821         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 822                         devfreq->profile->max_state,
 823                         sizeof(*devfreq->stats.time_in_state),
 824                         GFP_KERNEL);
 825         if (!devfreq->stats.time_in_state) {
 826                 mutex_unlock(&devfreq->lock);
 827                 err = -ENOMEM;
 828                 goto err_devfreq;
 829         }
 830
 831         devfreq->stats.total_trans = 0;
 832         devfreq->stats.last_update = get_jiffies_64();
 833
 834         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 835
 836         mutex_unlock(&devfreq->lock);
 837
 838         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 839                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 840         if (err < 0)
 841                 goto err_devfreq;
 842         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 843                                      DEV_PM_QOS_MAX_FREQUENCY,
 844                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 845         if (err < 0)
 846                 goto err_devfreq;
 847
 848         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 849         err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min,
 850                                       DEV_PM_QOS_MIN_FREQUENCY);
 851         if (err)
 852                 goto err_devfreq;
 853
 854         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 855         err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,
 856                                       DEV_PM_QOS_MAX_FREQUENCY);
 857         if (err)
 858                 goto err_devfreq;
 859
 860         mutex_lock(&devfreq_list_lock);
 861
 862         governor = try_then_request_governor(devfreq->governor_name);
 863         if (IS_ERR(governor)) {
 864                 dev_err(dev, "%s: Unable to find governor for the device\n",
 865                         __func__);
 866                 err = PTR_ERR(governor);
 867                 goto err_init;
 868         }
 869
 870         devfreq->governor = governor;
 871         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 872                                                 NULL);
 873         if (err) {
 874                 dev_err(dev, "%s: Unable to start governor for the device\n",
 875                         __func__);
 876                 goto err_init;
 877         }
 878
 879         list_add(&devfreq->node, &devfreq_list);
 880
 881         mutex_unlock(&devfreq_list_lock);
 882
 883         return devfreq;
 884
 885 err_init:
 886         mutex_unlock(&devfreq_list_lock);
 887 err_devfreq:
 888         devfreq_remove_device(devfreq);
 889         devfreq = NULL;
 890 err_dev:
 891         kfree(devfreq);
 892 err_out:
 893         return ERR_PTR(err);
 894 }
 895 EXPORT_SYMBOL(devfreq_add_device);
 896
 897 /**
 898  * devfreq_remove_device() - Remove devfreq feature from a device.
 899  * @devfreq:    the devfreq instance to be removed
 900  *
 901  * The opposite of devfreq_add_device().
 902  */
 903 int devfreq_remove_device(struct devfreq *devfreq)
 904 {
 905         if (!devfreq)
 906                 return -EINVAL;
 907
 908         if (devfreq->governor)
 909                 devfreq->governor->event_handler(devfreq,
 910                                                  DEVFREQ_GOV_STOP, NULL);
 911         device_unregister(&devfreq->dev);
 912
 913         return 0;
 914 }
 915 EXPORT_SYMBOL(devfreq_remove_device);
 916
 917 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 918 {
 919         struct devfreq **r = res;
 920
 921         if (WARN_ON(!r || !*r))
 922                 return 0;
 923
 924         return *r == data;
 925 }
 926
 927 static void devm_devfreq_dev_release(struct device *dev, void *res)
 928 {
 929         devfreq_remove_device(*(struct devfreq **)res);
 930 }
 931
 932 /**
 933  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 934  * @dev:        the device to add devfreq feature.
 935  * @profile:    device-specific profile to run devfreq.
 936  * @governor_name:      name of the policy to choose frequency.
 937  * @data:       private data for the governor. The devfreq framework does not
 938  *              touch this value.
 939  *
 940  * This function manages automatically the memory of devfreq device using device
 941  * resource management and simplify the free operation for memory of devfreq
 942  * device.
 943  */
 944 struct devfreq *devm_devfreq_add_device(struct device *dev,
 945                                         struct devfreq_dev_profile *profile,
 946                                         const char *governor_name,
 947                                         void *data)
 948 {
 949         struct devfreq **ptr, *devfreq;
 950
 951         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 952         if (!ptr)
 953                 return ERR_PTR(-ENOMEM);
 954
 955         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 956         if (IS_ERR(devfreq)) {
 957                 devres_free(ptr);
 958                 return devfreq;
 959         }
 960
 961         *ptr = devfreq;
 962         devres_add(dev, ptr);
 963
 964         return devfreq;
 965 }
 966 EXPORT_SYMBOL(devm_devfreq_add_device);
 967
 968 #ifdef CONFIG_OF
 969 /*
 970  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 971  * @dev - instance to the given device
 972  * @index - index into list of devfreq
 973  *
 974  * return the instance of devfreq device
 975  */
 976 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 977 {
 978         struct device_node *node;
 979         struct devfreq *devfreq;
 980
 981         if (!dev)
 982                 return ERR_PTR(-EINVAL);
 983
 984         if (!dev->of_node)
 985                 return ERR_PTR(-EINVAL);
 986
 987         node = of_parse_phandle(dev->of_node, "devfreq", index);
 988         if (!node)
 989                 return ERR_PTR(-ENODEV);
 990
 991         mutex_lock(&devfreq_list_lock);
 992         list_for_each_entry(devfreq, &devfreq_list, node) {
 993                 if (devfreq->dev.parent
 994                         && devfreq->dev.parent->of_node == node) {
 995                         mutex_unlock(&devfreq_list_lock);
 996                         of_node_put(node);
 997                         return devfreq;
 998                 }
 999         }
1000         mutex_unlock(&devfreq_list_lock);
1001         of_node_put(node);
1002
1003         return ERR_PTR(-EPROBE_DEFER);
1004 }
1005 #else
1006 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
1007 {
1008         return ERR_PTR(-ENODEV);
1009 }
1010 #endif /* CONFIG_OF */
1011 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1012
1013 /**
1014  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1015  * @dev:        the device from which to remove devfreq feature.
1016  * @devfreq:    the devfreq instance to be removed
1017  */
1018 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1019 {
1020         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1021                                devm_devfreq_dev_match, devfreq));
1022 }
1023 EXPORT_SYMBOL(devm_devfreq_remove_device);
1024
1025 /**
1026  * devfreq_suspend_device() - Suspend devfreq of a device.
1027  * @devfreq: the devfreq instance to be suspended
1028  *
1029  * This function is intended to be called by the pm callbacks
1030  * (e.g., runtime_suspend, suspend) of the device driver that
1031  * holds the devfreq.
1032  */
1033 int devfreq_suspend_device(struct devfreq *devfreq)
1034 {
1035         int ret;
1036
1037         if (!devfreq)
1038                 return -EINVAL;
1039
1040         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1041                 return 0;
1042
1043         if (devfreq->governor) {
1044                 ret = devfreq->governor->event_handler(devfreq,
1045                                         DEVFREQ_GOV_SUSPEND, NULL);
1046                 if (ret)
1047                         return ret;
1048         }
1049
1050         if (devfreq->suspend_freq) {
1051                 mutex_lock(&devfreq->lock);
1052                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1053                 mutex_unlock(&devfreq->lock);
1054                 if (ret)
1055                         return ret;
1056         }
1057
1058         return 0;
1059 }
1060 EXPORT_SYMBOL(devfreq_suspend_device);
1061
1062 /**
1063  * devfreq_resume_device() - Resume devfreq of a device.
1064  * @devfreq: the devfreq instance to be resumed
1065  *
1066  * This function is intended to be called by the pm callbacks
1067  * (e.g., runtime_resume, resume) of the device driver that
1068  * holds the devfreq.
1069  */
1070 int devfreq_resume_device(struct devfreq *devfreq)
1071 {
1072         int ret;
1073
1074         if (!devfreq)
1075                 return -EINVAL;
1076
1077         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1078                 return 0;
1079
1080         if (devfreq->resume_freq) {
1081                 mutex_lock(&devfreq->lock);
1082                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1083                 mutex_unlock(&devfreq->lock);
1084                 if (ret)
1085                         return ret;
1086         }
1087
1088         if (devfreq->governor) {
1089                 ret = devfreq->governor->event_handler(devfreq,
1090                                         DEVFREQ_GOV_RESUME, NULL);
1091                 if (ret)
1092                         return ret;
1093         }
1094
1095         return 0;
1096 }
1097 EXPORT_SYMBOL(devfreq_resume_device);
1098
1099 /**
1100  * devfreq_suspend() - Suspend devfreq governors and devices
1101  *
1102  * Called during system wide Suspend/Hibernate cycles for suspending governors
1103  * and devices preserving the state for resume. On some platforms the devfreq
1104  * device must have precise state (frequency) after resume in order to provide
1105  * fully operating setup.
1106  */
1107 void devfreq_suspend(void)
1108 {
1109         struct devfreq *devfreq;
1110         int ret;
1111
1112         mutex_lock(&devfreq_list_lock);
1113         list_for_each_entry(devfreq, &devfreq_list, node) {
1114                 ret = devfreq_suspend_device(devfreq);
1115                 if (ret)
1116                         dev_err(&devfreq->dev,
1117                                 "failed to suspend devfreq device\n");
1118         }
1119         mutex_unlock(&devfreq_list_lock);
1120 }
1121
1122 /**
1123  * devfreq_resume() - Resume devfreq governors and devices
1124  *
1125  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1126  * devices that are suspended with devfreq_suspend().
1127  */
1128 void devfreq_resume(void)
1129 {
1130         struct devfreq *devfreq;
1131         int ret;
1132
1133         mutex_lock(&devfreq_list_lock);
1134         list_for_each_entry(devfreq, &devfreq_list, node) {
1135                 ret = devfreq_resume_device(devfreq);
1136                 if (ret)
1137                         dev_warn(&devfreq->dev,
1138                                  "failed to resume devfreq device\n");
1139         }
1140         mutex_unlock(&devfreq_list_lock);
1141 }
1142
1143 /**
1144  * devfreq_add_governor() - Add devfreq governor
1145  * @governor:   the devfreq governor to be added
1146  */
1147 int devfreq_add_governor(struct devfreq_governor *governor)
1148 {
1149         struct devfreq_governor *g;
1150         struct devfreq *devfreq;
1151         int err = 0;
1152
1153         if (!governor) {
1154                 pr_err("%s: Invalid parameters.\n", __func__);
1155                 return -EINVAL;
1156         }
1157
1158         mutex_lock(&devfreq_list_lock);
1159         g = find_devfreq_governor(governor->name);
1160         if (!IS_ERR(g)) {
1161                 pr_err("%s: governor %s already registered\n", __func__,
1162                        g->name);
1163                 err = -EINVAL;
1164                 goto err_out;
1165         }
1166
1167         list_add(&governor->node, &devfreq_governor_list);
1168
1169         list_for_each_entry(devfreq, &devfreq_list, node) {
1170                 int ret = 0;
1171                 struct device *dev = devfreq->dev.parent;
1172
1173                 if (!strncmp(devfreq->governor_name, governor->name,
1174                              DEVFREQ_NAME_LEN)) {
1175                         /* The following should never occur */
1176                         if (devfreq->governor) {
1177                                 dev_warn(dev,
1178                                          "%s: Governor %s already present\n",
1179                                          __func__, devfreq->governor->name);
1180                                 ret = devfreq->governor->event_handler(devfreq,
1181                                                         DEVFREQ_GOV_STOP, NULL);
1182                                 if (ret) {
1183                                         dev_warn(dev,
1184                                                  "%s: Governor %s stop = %d\n",
1185                                                  __func__,
1186                                                  devfreq->governor->name, ret);
1187                                 }
1188                                 /* Fall through */
1189                         }
1190                         devfreq->governor = governor;
1191                         ret = devfreq->governor->event_handler(devfreq,
1192                                                 DEVFREQ_GOV_START, NULL);
1193                         if (ret) {
1194                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1195                                          __func__, devfreq->governor->name,
1196                                          ret);
1197                         }
1198                 }
1199         }
1200
1201 err_out:
1202         mutex_unlock(&devfreq_list_lock);
1203
1204         return err;
1205 }
1206 EXPORT_SYMBOL(devfreq_add_governor);
1207
1208 /**
1209  * devfreq_remove_governor() - Remove devfreq feature from a device.
1210  * @governor:   the devfreq governor to be removed
1211  */
1212 int devfreq_remove_governor(struct devfreq_governor *governor)
1213 {
1214         struct devfreq_governor *g;
1215         struct devfreq *devfreq;
1216         int err = 0;
1217
1218         if (!governor) {
1219                 pr_err("%s: Invalid parameters.\n", __func__);
1220                 return -EINVAL;
1221         }
1222
1223         mutex_lock(&devfreq_list_lock);
1224         g = find_devfreq_governor(governor->name);
1225         if (IS_ERR(g)) {
1226                 pr_err("%s: governor %s not registered\n", __func__,
1227                        governor->name);
1228                 err = PTR_ERR(g);
1229                 goto err_out;
1230         }
1231         list_for_each_entry(devfreq, &devfreq_list, node) {
1232                 int ret;
1233                 struct device *dev = devfreq->dev.parent;
1234
1235                 if (!strncmp(devfreq->governor_name, governor->name,
1236                              DEVFREQ_NAME_LEN)) {
1237                         /* we should have a devfreq governor! */
1238                         if (!devfreq->governor) {
1239                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1240                                          __func__, governor->name);
1241                                 continue;
1242                                 /* Fall through */
1243                         }
1244                         ret = devfreq->governor->event_handler(devfreq,
1245                                                 DEVFREQ_GOV_STOP, NULL);
1246                         if (ret) {
1247                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1248                                          __func__, devfreq->governor->name,
1249                                          ret);
1250                         }
1251                         devfreq->governor = NULL;
1252                 }
1253         }
1254
1255         list_del(&governor->node);
1256 err_out:
1257         mutex_unlock(&devfreq_list_lock);
1258
1259         return err;
1260 }
1261 EXPORT_SYMBOL(devfreq_remove_governor);
1262
1263 static ssize_t name_show(struct device *dev,
1264                         struct device_attribute *attr, char *buf)
1265 {
1266         struct devfreq *devfreq = to_devfreq(dev);
1267         return sprintf(buf, "%s\n", dev_name(devfreq->dev.parent));
1268 }
1269 static DEVICE_ATTR_RO(name);
1270
1271 static ssize_t governor_show(struct device *dev,
1272                              struct device_attribute *attr, char *buf)
1273 {
1274         if (!to_devfreq(dev)->governor)
1275                 return -EINVAL;
1276
1277         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
1278 }
1279
1280 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1281                               const char *buf, size_t count)
1282 {
1283         struct devfreq *df = to_devfreq(dev);
1284         int ret;
1285         char str_governor[DEVFREQ_NAME_LEN + 1];
1286         const struct devfreq_governor *governor, *prev_governor;
1287
1288         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1289         if (ret != 1)
1290                 return -EINVAL;
1291
1292         mutex_lock(&devfreq_list_lock);
1293         governor = try_then_request_governor(str_governor);
1294         if (IS_ERR(governor)) {
1295                 ret = PTR_ERR(governor);
1296                 goto out;
1297         }
1298         if (df->governor == governor) {
1299                 ret = 0;
1300                 goto out;
1301         } else if ((df->governor && df->governor->immutable) ||
1302                                         governor->immutable) {
1303                 ret = -EINVAL;
1304                 goto out;
1305         }
1306
1307         if (df->governor) {
1308                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1309                 if (ret) {
1310                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1311                                  __func__, df->governor->name, ret);
1312                         goto out;
1313                 }
1314         }
1315         prev_governor = df->governor;
1316         df->governor = governor;
1317         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1318         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1319         if (ret) {
1320                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1321                          __func__, df->governor->name, ret);
1322                 df->governor = prev_governor;
1323                 strncpy(df->governor_name, prev_governor->name,
1324                         DEVFREQ_NAME_LEN);
1325                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1326                 if (ret) {
1327                         dev_err(dev,
1328                                 "%s: reverting to Governor %s failed (%d)\n",
1329                                 __func__, df->governor_name, ret);
1330                         df->governor = NULL;
1331                 }
1332         }
1333 out:
1334         mutex_unlock(&devfreq_list_lock);
1335
1336         if (!ret)
1337                 ret = count;
1338         return ret;
1339 }
1340 static DEVICE_ATTR_RW(governor);
1341
1342 static ssize_t available_governors_show(struct device *d,
1343                                         struct device_attribute *attr,
1344                                         char *buf)
1345 {
1346         struct devfreq *df = to_devfreq(d);
1347         ssize_t count = 0;
1348
1349         mutex_lock(&devfreq_list_lock);
1350
1351         /*
1352          * The devfreq with immutable governor (e.g., passive) shows
1353          * only own governor.
1354          */
1355         if (df->governor && df->governor->immutable) {
1356                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1357                                   "%s ", df->governor_name);
1358         /*
1359          * The devfreq device shows the registered governor except for
1360          * immutable governors such as passive governor .
1361          */
1362         } else {
1363                 struct devfreq_governor *governor;
1364
1365                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1366                         if (governor->immutable)
1367                                 continue;
1368                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1369                                            "%s ", governor->name);
1370                 }
1371         }
1372
1373         mutex_unlock(&devfreq_list_lock);
1374
1375         /* Truncate the trailing space */
1376         if (count)
1377                 count--;
1378
1379         count += sprintf(&buf[count], "\n");
1380
1381         return count;
1382 }
1383 static DEVICE_ATTR_RO(available_governors);
1384
1385 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1386                              char *buf)
1387 {
1388         unsigned long freq;
1389         struct devfreq *devfreq = to_devfreq(dev);
1390
1391         if (devfreq->profile->get_cur_freq &&
1392                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1393                 return sprintf(buf, "%lu\n", freq);
1394
1395         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1396 }
1397 static DEVICE_ATTR_RO(cur_freq);
1398
1399 static ssize_t target_freq_show(struct device *dev,
1400                                 struct device_attribute *attr, char *buf)
1401 {
1402         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1403 }
1404 static DEVICE_ATTR_RO(target_freq);
1405
1406 static ssize_t polling_interval_show(struct device *dev,
1407                                      struct device_attribute *attr, char *buf)
1408 {
1409         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1410 }
1411
1412 static ssize_t polling_interval_store(struct device *dev,
1413                                       struct device_attribute *attr,
1414                                       const char *buf, size_t count)
1415 {
1416         struct devfreq *df = to_devfreq(dev);
1417         unsigned int value;
1418         int ret;
1419
1420         if (!df->governor)
1421                 return -EINVAL;
1422
1423         ret = sscanf(buf, "%u", &value);
1424         if (ret != 1)
1425                 return -EINVAL;
1426
1427         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1428         ret = count;
1429
1430         return ret;
1431 }
1432 static DEVICE_ATTR_RW(polling_interval);
1433
1434 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1435                               const char *buf, size_t count)
1436 {
1437         struct devfreq *df = to_devfreq(dev);
1438         unsigned long value;
1439         int ret;
1440
1441         /*
1442          * Protect against theoretical sysfs writes between
1443          * device_add and dev_pm_qos_add_request
1444          */
1445         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1446                 return -EAGAIN;
1447
1448         ret = sscanf(buf, "%lu", &value);
1449         if (ret != 1)
1450                 return -EINVAL;
1451
1452         /* Round down to kHz for PM QoS */
1453         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1454                                         value / HZ_PER_KHZ);
1455         if (ret < 0)
1456                 return ret;
1457
1458         return count;
1459 }
1460
1461 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1462                              char *buf)
1463 {
1464         struct devfreq *df = to_devfreq(dev);
1465         unsigned long min_freq, max_freq;
1466
1467         mutex_lock(&df->lock);
1468         get_freq_range(df, &min_freq, &max_freq);
1469         mutex_unlock(&df->lock);
1470
1471         return sprintf(buf, "%lu\n", min_freq);
1472 }
1473 static DEVICE_ATTR_RW(min_freq);
1474
1475 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1476                               const char *buf, size_t count)
1477 {
1478         struct devfreq *df = to_devfreq(dev);
1479         unsigned long value;
1480         int ret;
1481
1482         /*
1483          * Protect against theoretical sysfs writes between
1484          * device_add and dev_pm_qos_add_request
1485          */
1486         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1487                 return -EINVAL;
1488
1489         ret = sscanf(buf, "%lu", &value);
1490         if (ret != 1)
1491                 return -EINVAL;
1492
1493         /*
1494          * PM QoS frequencies are in kHz so we need to convert. Convert by
1495          * rounding upwards so that the acceptable interval never shrinks.
1496          *
1497          * For example if the user writes "666666666" to sysfs this value will
1498          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1499          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1500          *
1501          * A value of zero means "no limit".
1502          */
1503         if (value)
1504                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1505         else
1506                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1507
1508         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1509         if (ret < 0)
1510                 return ret;
1511
1512         return count;
1513 }
1514
1515 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1516                              char *buf)
1517 {
1518         struct devfreq *df = to_devfreq(dev);
1519         unsigned long min_freq, max_freq;
1520
1521         mutex_lock(&df->lock);
1522         get_freq_range(df, &min_freq, &max_freq);
1523         mutex_unlock(&df->lock);
1524
1525         return sprintf(buf, "%lu\n", max_freq);
1526 }
1527 static DEVICE_ATTR_RW(max_freq);
1528
1529 static ssize_t available_frequencies_show(struct device *d,
1530                                           struct device_attribute *attr,
1531                                           char *buf)
1532 {
1533         struct devfreq *df = to_devfreq(d);
1534         ssize_t count = 0;
1535         int i;
1536
1537         mutex_lock(&df->lock);
1538
1539         for (i = 0; i < df->profile->max_state; i++)
1540                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1541                                 "%lu ", df->profile->freq_table[i]);
1542
1543         mutex_unlock(&df->lock);
1544         /* Truncate the trailing space */
1545         if (count)
1546                 count--;
1547
1548         count += sprintf(&buf[count], "\n");
1549
1550         return count;
1551 }
1552 static DEVICE_ATTR_RO(available_frequencies);
1553
1554 static ssize_t trans_stat_show(struct device *dev,
1555                                struct device_attribute *attr, char *buf)
1556 {
1557         struct devfreq *devfreq = to_devfreq(dev);
1558         ssize_t len;
1559         int i, j;
1560         unsigned int max_state = devfreq->profile->max_state;
1561
1562         if (max_state == 0)
1563                 return sprintf(buf, "Not Supported.\n");
1564
1565         mutex_lock(&devfreq->lock);
1566         if (!devfreq->stop_polling &&
1567                         devfreq_update_status(devfreq, devfreq->previous_freq)) {
1568                 mutex_unlock(&devfreq->lock);
1569                 return 0;
1570         }
1571         mutex_unlock(&devfreq->lock);
1572
1573         len = sprintf(buf, "     From  :   To\n");
1574         len += sprintf(buf + len, "           :");
1575         for (i = 0; i < max_state; i++)
1576                 len += sprintf(buf + len, "%10lu",
1577                                 devfreq->profile->freq_table[i]);
1578
1579         len += sprintf(buf + len, "   time(ms)\n");
1580
1581         for (i = 0; i < max_state; i++) {
1582                 if (devfreq->profile->freq_table[i]
1583                                         == devfreq->previous_freq) {
1584                         len += sprintf(buf + len, "*");
1585                 } else {
1586                         len += sprintf(buf + len, " ");
1587                 }
1588                 len += sprintf(buf + len, "%10lu:",
1589                                 devfreq->profile->freq_table[i]);
1590                 for (j = 0; j < max_state; j++)
1591                         len += sprintf(buf + len, "%10u",
1592                                 devfreq->stats.trans_table[(i * max_state) + j]);
1593
1594                 len += sprintf(buf + len, "%10llu\n", (u64)
1595                         jiffies64_to_msecs(devfreq->stats.time_in_state[i]));
1596         }
1597
1598         len += sprintf(buf + len, "Total transition : %u\n",
1599                                         devfreq->stats.total_trans);
1600         return len;
1601 }
1602
1603 static ssize_t trans_stat_store(struct device *dev,
1604                                 struct device_attribute *attr,
1605                                 const char *buf, size_t count)
1606 {
1607         struct devfreq *df = to_devfreq(dev);
1608         int err, value;
1609
1610         if (df->profile->max_state == 0)
1611                 return count;
1612
1613         err = kstrtoint(buf, 10, &value);
1614         if (err || value != 0)
1615                 return -EINVAL;
1616
1617         mutex_lock(&df->lock);
1618         memset(df->stats.time_in_state, 0, (df->profile->max_state *
1619                                         sizeof(*df->stats.time_in_state)));
1620         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1621                                         df->profile->max_state,
1622                                         df->profile->max_state));
1623         df->stats.total_trans = 0;
1624         df->stats.last_update = get_jiffies_64();
1625         mutex_unlock(&df->lock);
1626
1627         return count;
1628 }
1629 static DEVICE_ATTR_RW(trans_stat);
1630
1631 static struct attribute *devfreq_attrs[] = {
1632         &dev_attr_name.attr,
1633         &dev_attr_governor.attr,
1634         &dev_attr_available_governors.attr,
1635         &dev_attr_cur_freq.attr,
1636         &dev_attr_available_frequencies.attr,
1637         &dev_attr_target_freq.attr,
1638         &dev_attr_polling_interval.attr,
1639         &dev_attr_min_freq.attr,
1640         &dev_attr_max_freq.attr,
1641         &dev_attr_trans_stat.attr,
1642         NULL,
1643 };
1644 ATTRIBUTE_GROUPS(devfreq);
1645
1646 /**
1647  * devfreq_summary_show() - Show the summary of the devfreq devices
1648  * @s:          seq_file instance to show the summary of devfreq devices
1649  * @data:       not used
1650  *
1651  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1652  * It helps that user can know the detailed information of the devfreq devices.
1653  *
1654  * Return 0 always because it shows the information without any data change.
1655  */
1656 static int devfreq_summary_show(struct seq_file *s, void *data)
1657 {
1658         struct devfreq *devfreq;
1659         struct devfreq *p_devfreq = NULL;
1660         unsigned long cur_freq, min_freq, max_freq;
1661         unsigned int polling_ms;
1662
1663         seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
1664                         "dev_name",
1665                         "dev",
1666                         "parent_dev",
1667                         "governor",
1668                         "polling_ms",
1669                         "cur_freq_Hz",
1670                         "min_freq_Hz",
1671                         "max_freq_Hz");
1672         seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
1673                         "------------------------------",
1674                         "----------",
1675                         "----------",
1676                         "---------------",
1677                         "----------",
1678                         "------------",
1679                         "------------",
1680                         "------------");
1681
1682         mutex_lock(&devfreq_list_lock);
1683
1684         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1685 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1686                 if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
1687                                                         DEVFREQ_NAME_LEN)) {
1688                         struct devfreq_passive_data *data = devfreq->data;
1689
1690                         if (data)
1691                                 p_devfreq = data->parent;
1692                 } else {
1693                         p_devfreq = NULL;
1694                 }
1695 #endif
1696
1697                 mutex_lock(&devfreq->lock);
1698                 cur_freq = devfreq->previous_freq,
1699                 get_freq_range(devfreq, &min_freq, &max_freq);
1700                 polling_ms = devfreq->profile->polling_ms,
1701                 mutex_unlock(&devfreq->lock);
1702
1703                 seq_printf(s,
1704                         "%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
1705                         dev_name(devfreq->dev.parent),
1706                         dev_name(&devfreq->dev),
1707                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1708                         devfreq->governor_name,
1709                         polling_ms,
1710                         cur_freq,
1711                         min_freq,
1712                         max_freq);
1713         }
1714
1715         mutex_unlock(&devfreq_list_lock);
1716
1717         return 0;
1718 }
1719 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1720
1721 static int __init devfreq_init(void)
1722 {
1723         devfreq_class = class_create(THIS_MODULE, "devfreq");
1724         if (IS_ERR(devfreq_class)) {
1725                 pr_err("%s: couldn't create class\n", __FILE__);
1726                 return PTR_ERR(devfreq_class);
1727         }
1728
1729         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1730         if (!devfreq_wq) {
1731                 class_destroy(devfreq_class);
1732                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1733                 return -ENOMEM;
1734         }
1735         devfreq_class->dev_groups = devfreq_groups;
1736
1737         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
1738         debugfs_create_file("devfreq_summary", 0444,
1739                                 devfreq_debugfs, NULL,
1740                                 &devfreq_summary_fops);
1741
1742         return 0;
1743 }
1744 subsys_initcall(devfreq_init);
1745
1746 /*
1747  * The following are helper functions for devfreq user device drivers with
1748  * OPP framework.
1749  */
1750
1751 /**
1752  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1753  *                           freq value given to target callback.
1754  * @dev:        The devfreq user device. (parent of devfreq)
1755  * @freq:       The frequency given to target function
1756  * @flags:      Flags handed from devfreq framework.
1757  *
1758  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1759  * use.
1760  */
1761 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1762                                            unsigned long *freq,
1763                                            u32 flags)
1764 {
1765         struct dev_pm_opp *opp;
1766
1767         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1768                 /* The freq is an upper bound. opp should be lower */
1769                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1770
1771                 /* If not available, use the closest opp */
1772                 if (opp == ERR_PTR(-ERANGE))
1773                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1774         } else {
1775                 /* The freq is an lower bound. opp should be higher */
1776                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1777
1778                 /* If not available, use the closest opp */
1779                 if (opp == ERR_PTR(-ERANGE))
1780                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1781         }
1782
1783         return opp;
1784 }
1785 EXPORT_SYMBOL(devfreq_recommended_opp);
1786
1787 /**
1788  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1789  *                                   for any changes in the OPP availability
1790  *                                   changes
1791  * @dev:        The devfreq user device. (parent of devfreq)
1792  * @devfreq:    The devfreq object.
1793  */
1794 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1795 {
1796         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1797 }
1798 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1799
1800 /**
1801  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1802  *                                     notified for any changes in the OPP
1803  *                                     availability changes anymore.
1804  * @dev:        The devfreq user device. (parent of devfreq)
1805  * @devfreq:    The devfreq object.
1806  *
1807  * At exit() callback of devfreq_dev_profile, this must be included if
1808  * devfreq_recommended_opp is used.
1809  */
1810 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1811 {
1812         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1813 }
1814 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1815
1816 static void devm_devfreq_opp_release(struct device *dev, void *res)
1817 {
1818         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1819 }
1820
1821 /**
1822  * devm_devfreq_register_opp_notifier() - Resource-managed
1823  *                                        devfreq_register_opp_notifier()
1824  * @dev:        The devfreq user device. (parent of devfreq)
1825  * @devfreq:    The devfreq object.
1826  */
1827 int devm_devfreq_register_opp_notifier(struct device *dev,
1828                                        struct devfreq *devfreq)
1829 {
1830         struct devfreq **ptr;
1831         int ret;
1832
1833         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1834         if (!ptr)
1835                 return -ENOMEM;
1836
1837         ret = devfreq_register_opp_notifier(dev, devfreq);
1838         if (ret) {
1839                 devres_free(ptr);
1840                 return ret;
1841         }
1842
1843         *ptr = devfreq;
1844         devres_add(dev, ptr);
1845
1846         return 0;
1847 }
1848 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1849
1850 /**
1851  * devm_devfreq_unregister_opp_notifier() - Resource-managed
1852  *                                          devfreq_unregister_opp_notifier()
1853  * @dev:        The devfreq user device. (parent of devfreq)
1854  * @devfreq:    The devfreq object.
1855  */
1856 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1857                                          struct devfreq *devfreq)
1858 {
1859         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1860                                devm_devfreq_dev_match, devfreq));
1861 }
1862 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1863
1864 /**
1865  * devfreq_register_notifier() - Register a driver with devfreq
1866  * @devfreq:    The devfreq object.
1867  * @nb:         The notifier block to register.
1868  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1869  */
1870 int devfreq_register_notifier(struct devfreq *devfreq,
1871                               struct notifier_block *nb,
1872                               unsigned int list)
1873 {
1874         int ret = 0;
1875
1876         if (!devfreq)
1877                 return -EINVAL;
1878
1879         switch (list) {
1880         case DEVFREQ_TRANSITION_NOTIFIER:
1881                 ret = srcu_notifier_chain_register(
1882                                 &devfreq->transition_notifier_list, nb);
1883                 break;
1884         default:
1885                 ret = -EINVAL;
1886         }
1887
1888         return ret;
1889 }
1890 EXPORT_SYMBOL(devfreq_register_notifier);
1891
1892 /*
1893  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1894  * @devfreq:    The devfreq object.
1895  * @nb:         The notifier block to be unregistered.
1896  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1897  */
1898 int devfreq_unregister_notifier(struct devfreq *devfreq,
1899                                 struct notifier_block *nb,
1900                                 unsigned int list)
1901 {
1902         int ret = 0;
1903
1904         if (!devfreq)
1905                 return -EINVAL;
1906
1907         switch (list) {
1908         case DEVFREQ_TRANSITION_NOTIFIER:
1909                 ret = srcu_notifier_chain_unregister(
1910                                 &devfreq->transition_notifier_list, nb);
1911                 break;
1912         default:
1913                 ret = -EINVAL;
1914         }
1915
1916         return ret;
1917 }
1918 EXPORT_SYMBOL(devfreq_unregister_notifier);
1919
1920 struct devfreq_notifier_devres {
1921         struct devfreq *devfreq;
1922         struct notifier_block *nb;
1923         unsigned int list;
1924 };
1925
1926 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1927 {
1928         struct devfreq_notifier_devres *this = res;
1929
1930         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1931 }
1932
1933 /**
1934  * devm_devfreq_register_notifier()
1935  *      - Resource-managed devfreq_register_notifier()
1936  * @dev:        The devfreq user device. (parent of devfreq)
1937  * @devfreq:    The devfreq object.
1938  * @nb:         The notifier block to be unregistered.
1939  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1940  */
1941 int devm_devfreq_register_notifier(struct device *dev,
1942                                 struct devfreq *devfreq,
1943                                 struct notifier_block *nb,
1944                                 unsigned int list)
1945 {
1946         struct devfreq_notifier_devres *ptr;
1947         int ret;
1948
1949         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1950                                 GFP_KERNEL);
1951         if (!ptr)
1952                 return -ENOMEM;
1953
1954         ret = devfreq_register_notifier(devfreq, nb, list);
1955         if (ret) {
1956                 devres_free(ptr);
1957                 return ret;
1958         }
1959
1960         ptr->devfreq = devfreq;
1961         ptr->nb = nb;
1962         ptr->list = list;
1963         devres_add(dev, ptr);
1964
1965         return 0;
1966 }
1967 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1968
1969 /**
1970  * devm_devfreq_unregister_notifier()
1971  *      - Resource-managed devfreq_unregister_notifier()
1972  * @dev:        The devfreq user device. (parent of devfreq)
1973  * @devfreq:    The devfreq object.
1974  * @nb:         The notifier block to be unregistered.
1975  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1976  */
1977 void devm_devfreq_unregister_notifier(struct device *dev,
1978                                       struct devfreq *devfreq,
1979                                       struct notifier_block *nb,
1980                                       unsigned int list)
1981 {
1982         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1983                                devm_devfreq_dev_match, devfreq));
1984 }
1985 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);