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/devfreq_cooling.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/export.h>
  19 #include <linux/slab.h>
  20 #include <linux/stat.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/devfreq.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/hrtimer.h>
  28 #include <linux/of.h>
  29 #include <linux/pm_qos.h>
  30 #include <linux/units.h>
  31 #include "governor.h"
  32
  33 #define CREATE_TRACE_POINTS
  34 #include <trace/events/devfreq.h>
  35
  36 #define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
  37 #define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
  38
  39 static struct class *devfreq_class;
  40 static struct dentry *devfreq_debugfs;
  41
  42 /*
  43  * devfreq core provides delayed work based load monitoring helper
  44  * functions. Governors can use these or can implement their own
  45  * monitoring mechanism.
  46  */
  47 static struct workqueue_struct *devfreq_wq;
  48
  49 /* The list of all device-devfreq governors */
  50 static LIST_HEAD(devfreq_governor_list);
  51 /* The list of all device-devfreq */
  52 static LIST_HEAD(devfreq_list);
  53 static DEFINE_MUTEX(devfreq_list_lock);
  54
  55 static const char timer_name[][DEVFREQ_NAME_LEN] = {
  56         [DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
  57         [DEVFREQ_TIMER_DELAYED] = { "delayed" },
  58 };
  59
  60 /**
  61  * find_device_devfreq() - find devfreq struct using device pointer
  62  * @dev:        device pointer used to lookup device devfreq.
  63  *
  64  * Search the list of device devfreqs and return the matched device's
  65  * devfreq info. devfreq_list_lock should be held by the caller.
  66  */
  67 static struct devfreq *find_device_devfreq(struct device *dev)
  68 {
  69         struct devfreq *tmp_devfreq;
  70
  71         lockdep_assert_held(&devfreq_list_lock);
  72
  73         if (IS_ERR_OR_NULL(dev)) {
  74                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  75                 return ERR_PTR(-EINVAL);
  76         }
  77
  78         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  79                 if (tmp_devfreq->dev.parent == dev)
  80                         return tmp_devfreq;
  81         }
  82
  83         return ERR_PTR(-ENODEV);
  84 }
  85
  86 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  87 {
  88         struct dev_pm_opp *opp;
  89         unsigned long min_freq = 0;
  90
  91         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  92         if (IS_ERR(opp))
  93                 min_freq = 0;
  94         else
  95                 dev_pm_opp_put(opp);
  96
  97         return min_freq;
  98 }
  99
 100 static unsigned long find_available_max_freq(struct devfreq *devfreq)
 101 {
 102         struct dev_pm_opp *opp;
 103         unsigned long max_freq = ULONG_MAX;
 104
 105         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
 106         if (IS_ERR(opp))
 107                 max_freq = 0;
 108         else
 109                 dev_pm_opp_put(opp);
 110
 111         return max_freq;
 112 }
 113
 114 /**
 115  * devfreq_get_freq_range() - Get the current freq range
 116  * @devfreq:    the devfreq instance
 117  * @min_freq:   the min frequency
 118  * @max_freq:   the max frequency
 119  *
 120  * This takes into consideration all constraints.
 121  */
 122 void devfreq_get_freq_range(struct devfreq *devfreq,
 123                             unsigned long *min_freq,
 124                             unsigned long *max_freq)
 125 {
 126         unsigned long *freq_table = devfreq->profile->freq_table;
 127         s32 qos_min_freq, qos_max_freq;
 128
 129         lockdep_assert_held(&devfreq->lock);
 130
 131         /*
 132          * Initialize minimum/maximum frequency from freq table.
 133          * The devfreq drivers can initialize this in either ascending or
 134          * descending order and devfreq core supports both.
 135          */
 136         if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
 137                 *min_freq = freq_table[0];
 138                 *max_freq = freq_table[devfreq->profile->max_state - 1];
 139         } else {
 140                 *min_freq = freq_table[devfreq->profile->max_state - 1];
 141                 *max_freq = freq_table[0];
 142         }
 143
 144         /* Apply constraints from PM QoS */
 145         qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 146                                              DEV_PM_QOS_MIN_FREQUENCY);
 147         qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 148                                              DEV_PM_QOS_MAX_FREQUENCY);
 149         *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 150         if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 151                 *max_freq = min(*max_freq,
 152                                 (unsigned long)HZ_PER_KHZ * qos_max_freq);
 153
 154         /* Apply constraints from OPP interface */
 155         *min_freq = max(*min_freq, devfreq->scaling_min_freq);
 156         *max_freq = min(*max_freq, devfreq->scaling_max_freq);
 157
 158         if (*min_freq > *max_freq)
 159                 *min_freq = *max_freq;
 160 }
 161 EXPORT_SYMBOL(devfreq_get_freq_range);
 162
 163 /**
 164  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 165  * @devfreq:    the devfreq instance
 166  * @freq:       the target frequency
 167  */
 168 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 169 {
 170         int lev;
 171
 172         for (lev = 0; lev < devfreq->profile->max_state; lev++)
 173                 if (freq == devfreq->profile->freq_table[lev])
 174                         return lev;
 175
 176         return -EINVAL;
 177 }
 178
 179 static int set_freq_table(struct devfreq *devfreq)
 180 {
 181         struct devfreq_dev_profile *profile = devfreq->profile;
 182         struct dev_pm_opp *opp;
 183         unsigned long freq;
 184         int i, count;
 185
 186         /* Initialize the freq_table from OPP table */
 187         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 188         if (count <= 0)
 189                 return -EINVAL;
 190
 191         profile->max_state = count;
 192         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 193                                         profile->max_state,
 194                                         sizeof(*profile->freq_table),
 195                                         GFP_KERNEL);
 196         if (!profile->freq_table) {
 197                 profile->max_state = 0;
 198                 return -ENOMEM;
 199         }
 200
 201         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 202                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 203                 if (IS_ERR(opp)) {
 204                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 205                         profile->max_state = 0;
 206                         return PTR_ERR(opp);
 207                 }
 208                 dev_pm_opp_put(opp);
 209                 profile->freq_table[i] = freq;
 210         }
 211
 212         return 0;
 213 }
 214
 215 /**
 216  * devfreq_update_status() - Update statistics of devfreq behavior
 217  * @devfreq:    the devfreq instance
 218  * @freq:       the update target frequency
 219  */
 220 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 221 {
 222         int lev, prev_lev, ret = 0;
 223         u64 cur_time;
 224
 225         lockdep_assert_held(&devfreq->lock);
 226         cur_time = get_jiffies_64();
 227
 228         /* Immediately exit if previous_freq is not initialized yet. */
 229         if (!devfreq->previous_freq)
 230                 goto out;
 231
 232         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 233         if (prev_lev < 0) {
 234                 ret = prev_lev;
 235                 goto out;
 236         }
 237
 238         devfreq->stats.time_in_state[prev_lev] +=
 239                         cur_time - devfreq->stats.last_update;
 240
 241         lev = devfreq_get_freq_level(devfreq, freq);
 242         if (lev < 0) {
 243                 ret = lev;
 244                 goto out;
 245         }
 246
 247         if (lev != prev_lev) {
 248                 devfreq->stats.trans_table[
 249                         (prev_lev * devfreq->profile->max_state) + lev]++;
 250                 devfreq->stats.total_trans++;
 251         }
 252
 253 out:
 254         devfreq->stats.last_update = cur_time;
 255         return ret;
 256 }
 257 EXPORT_SYMBOL(devfreq_update_status);
 258
 259 /**
 260  * find_devfreq_governor() - find devfreq governor from name
 261  * @name:       name of the governor
 262  *
 263  * Search the list of devfreq governors and return the matched
 264  * governor's pointer. devfreq_list_lock should be held by the caller.
 265  */
 266 static struct devfreq_governor *find_devfreq_governor(const char *name)
 267 {
 268         struct devfreq_governor *tmp_governor;
 269
 270         lockdep_assert_held(&devfreq_list_lock);
 271
 272         if (IS_ERR_OR_NULL(name)) {
 273                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 274                 return ERR_PTR(-EINVAL);
 275         }
 276
 277         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 278                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 279                         return tmp_governor;
 280         }
 281
 282         return ERR_PTR(-ENODEV);
 283 }
 284
 285 /**
 286  * try_then_request_governor() - Try to find the governor and request the
 287  *                               module if is not found.
 288  * @name:       name of the governor
 289  *
 290  * Search the list of devfreq governors and request the module and try again
 291  * if is not found. This can happen when both drivers (the governor driver
 292  * and the driver that call devfreq_add_device) are built as modules.
 293  * devfreq_list_lock should be held by the caller. Returns the matched
 294  * governor's pointer or an error pointer.
 295  */
 296 static struct devfreq_governor *try_then_request_governor(const char *name)
 297 {
 298         struct devfreq_governor *governor;
 299         int err = 0;
 300
 301         lockdep_assert_held(&devfreq_list_lock);
 302
 303         if (IS_ERR_OR_NULL(name)) {
 304                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 305                 return ERR_PTR(-EINVAL);
 306         }
 307
 308         governor = find_devfreq_governor(name);
 309         if (IS_ERR(governor)) {
 310                 mutex_unlock(&devfreq_list_lock);
 311
 312                 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 313                              DEVFREQ_NAME_LEN))
 314                         err = request_module("governor_%s", "simpleondemand");
 315                 else
 316                         err = request_module("governor_%s", name);
 317                 /* Restore previous state before return */
 318                 mutex_lock(&devfreq_list_lock);
 319                 if (err)
 320                         return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 321
 322                 governor = find_devfreq_governor(name);
 323         }
 324
 325         return governor;
 326 }
 327
 328 static int devfreq_notify_transition(struct devfreq *devfreq,
 329                 struct devfreq_freqs *freqs, unsigned int state)
 330 {
 331         if (!devfreq)
 332                 return -EINVAL;
 333
 334         switch (state) {
 335         case DEVFREQ_PRECHANGE:
 336                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 337                                 DEVFREQ_PRECHANGE, freqs);
 338                 break;
 339
 340         case DEVFREQ_POSTCHANGE:
 341                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 342                                 DEVFREQ_POSTCHANGE, freqs);
 343                 break;
 344         default:
 345                 return -EINVAL;
 346         }
 347
 348         return 0;
 349 }
 350
 351 static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 352                               u32 flags)
 353 {
 354         struct devfreq_freqs freqs;
 355         unsigned long cur_freq;
 356         int err = 0;
 357
 358         if (devfreq->profile->get_cur_freq)
 359                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 360         else
 361                 cur_freq = devfreq->previous_freq;
 362
 363         freqs.old = cur_freq;
 364         freqs.new = new_freq;
 365         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 366
 367         err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 368         if (err) {
 369                 freqs.new = cur_freq;
 370                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 371                 return err;
 372         }
 373
 374         /*
 375          * Print devfreq_frequency trace information between DEVFREQ_PRECHANGE
 376          * and DEVFREQ_POSTCHANGE because for showing the correct frequency
 377          * change order of between devfreq device and passive devfreq device.
 378          */
 379         if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
 380                 trace_devfreq_frequency(devfreq, new_freq, cur_freq);
 381
 382         freqs.new = new_freq;
 383         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 384
 385         if (devfreq_update_status(devfreq, new_freq))
 386                 dev_warn(&devfreq->dev,
 387                          "Couldn't update frequency transition information.\n");
 388
 389         devfreq->previous_freq = new_freq;
 390
 391         if (devfreq->suspend_freq)
 392                 devfreq->resume_freq = new_freq;
 393
 394         return err;
 395 }
 396
 397 /**
 398  * devfreq_update_target() - Reevaluate the device and configure frequency
 399  *                         on the final stage.
 400  * @devfreq:    the devfreq instance.
 401  * @freq:       the new frequency of parent device. This argument
 402  *              is only used for devfreq device using passive governor.
 403  *
 404  * Note: Lock devfreq->lock before calling devfreq_update_target. This function
 405  *       should be only used by both update_devfreq() and devfreq governors.
 406  */
 407 int devfreq_update_target(struct devfreq *devfreq, unsigned long freq)
 408 {
 409         unsigned long min_freq, max_freq;
 410         int err = 0;
 411         u32 flags = 0;
 412
 413         lockdep_assert_held(&devfreq->lock);
 414
 415         if (!devfreq->governor)
 416                 return -EINVAL;
 417
 418         /* Reevaluate the proper frequency */
 419         err = devfreq->governor->get_target_freq(devfreq, &freq);
 420         if (err)
 421                 return err;
 422         devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 423
 424         if (freq < min_freq) {
 425                 freq = min_freq;
 426                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 427         }
 428         if (freq > max_freq) {
 429                 freq = max_freq;
 430                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 431         }
 432
 433         return devfreq_set_target(devfreq, freq, flags);
 434 }
 435 EXPORT_SYMBOL(devfreq_update_target);
 436
 437 /* Load monitoring helper functions for governors use */
 438
 439 /**
 440  * update_devfreq() - Reevaluate the device and configure frequency.
 441  * @devfreq:    the devfreq instance.
 442  *
 443  * Note: Lock devfreq->lock before calling update_devfreq
 444  *       This function is exported for governors.
 445  */
 446 int update_devfreq(struct devfreq *devfreq)
 447 {
 448         return devfreq_update_target(devfreq, 0L);
 449 }
 450 EXPORT_SYMBOL(update_devfreq);
 451
 452 /**
 453  * devfreq_monitor() - Periodically poll devfreq objects.
 454  * @work:       the work struct used to run devfreq_monitor periodically.
 455  *
 456  */
 457 static void devfreq_monitor(struct work_struct *work)
 458 {
 459         int err;
 460         struct devfreq *devfreq = container_of(work,
 461                                         struct devfreq, work.work);
 462
 463         mutex_lock(&devfreq->lock);
 464         err = update_devfreq(devfreq);
 465         if (err)
 466                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 467
 468         queue_delayed_work(devfreq_wq, &devfreq->work,
 469                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 470         mutex_unlock(&devfreq->lock);
 471
 472         trace_devfreq_monitor(devfreq);
 473 }
 474
 475 /**
 476  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 477  * @devfreq:    the devfreq instance.
 478  *
 479  * Helper function for starting devfreq device load monitoring. By
 480  * default delayed work based monitoring is supported. Function
 481  * to be called from governor in response to DEVFREQ_GOV_START
 482  * event when device is added to devfreq framework.
 483  */
 484 void devfreq_monitor_start(struct devfreq *devfreq)
 485 {
 486         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 487                 return;
 488
 489         switch (devfreq->profile->timer) {
 490         case DEVFREQ_TIMER_DEFERRABLE:
 491                 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 492                 break;
 493         case DEVFREQ_TIMER_DELAYED:
 494                 INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
 495                 break;
 496         default:
 497                 return;
 498         }
 499
 500         if (devfreq->profile->polling_ms)
 501                 queue_delayed_work(devfreq_wq, &devfreq->work,
 502                         msecs_to_jiffies(devfreq->profile->polling_ms));
 503 }
 504 EXPORT_SYMBOL(devfreq_monitor_start);
 505
 506 /**
 507  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 508  * @devfreq:    the devfreq instance.
 509  *
 510  * Helper function to stop devfreq device load monitoring. Function
 511  * to be called from governor in response to DEVFREQ_GOV_STOP
 512  * event when device is removed from devfreq framework.
 513  */
 514 void devfreq_monitor_stop(struct devfreq *devfreq)
 515 {
 516         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 517                 return;
 518
 519         cancel_delayed_work_sync(&devfreq->work);
 520 }
 521 EXPORT_SYMBOL(devfreq_monitor_stop);
 522
 523 /**
 524  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 525  * @devfreq:    the devfreq instance.
 526  *
 527  * Helper function to suspend devfreq device load monitoring. Function
 528  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 529  * event or when polling interval is set to zero.
 530  *
 531  * Note: Though this function is same as devfreq_monitor_stop(),
 532  * intentionally kept separate to provide hooks for collecting
 533  * transition statistics.
 534  */
 535 void devfreq_monitor_suspend(struct devfreq *devfreq)
 536 {
 537         mutex_lock(&devfreq->lock);
 538         if (devfreq->stop_polling) {
 539                 mutex_unlock(&devfreq->lock);
 540                 return;
 541         }
 542
 543         devfreq_update_status(devfreq, devfreq->previous_freq);
 544         devfreq->stop_polling = true;
 545         mutex_unlock(&devfreq->lock);
 546
 547         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 548                 return;
 549
 550         cancel_delayed_work_sync(&devfreq->work);
 551 }
 552 EXPORT_SYMBOL(devfreq_monitor_suspend);
 553
 554 /**
 555  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 556  * @devfreq:    the devfreq instance.
 557  *
 558  * Helper function to resume devfreq device load monitoring. Function
 559  * to be called from governor in response to DEVFREQ_GOV_RESUME
 560  * event or when polling interval is set to non-zero.
 561  */
 562 void devfreq_monitor_resume(struct devfreq *devfreq)
 563 {
 564         unsigned long freq;
 565
 566         mutex_lock(&devfreq->lock);
 567
 568         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 569                 goto out_update;
 570
 571         if (!devfreq->stop_polling)
 572                 goto out;
 573
 574         if (!delayed_work_pending(&devfreq->work) &&
 575                         devfreq->profile->polling_ms)
 576                 queue_delayed_work(devfreq_wq, &devfreq->work,
 577                         msecs_to_jiffies(devfreq->profile->polling_ms));
 578
 579 out_update:
 580         devfreq->stats.last_update = get_jiffies_64();
 581         devfreq->stop_polling = false;
 582
 583         if (devfreq->profile->get_cur_freq &&
 584                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 585                 devfreq->previous_freq = freq;
 586
 587 out:
 588         mutex_unlock(&devfreq->lock);
 589 }
 590 EXPORT_SYMBOL(devfreq_monitor_resume);
 591
 592 /**
 593  * devfreq_update_interval() - Update device devfreq monitoring interval
 594  * @devfreq:    the devfreq instance.
 595  * @delay:      new polling interval to be set.
 596  *
 597  * Helper function to set new load monitoring polling interval. Function
 598  * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 599  */
 600 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 601 {
 602         unsigned int cur_delay = devfreq->profile->polling_ms;
 603         unsigned int new_delay = *delay;
 604
 605         mutex_lock(&devfreq->lock);
 606         devfreq->profile->polling_ms = new_delay;
 607
 608         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 609                 goto out;
 610
 611         if (devfreq->stop_polling)
 612                 goto out;
 613
 614         /* if new delay is zero, stop polling */
 615         if (!new_delay) {
 616                 mutex_unlock(&devfreq->lock);
 617                 cancel_delayed_work_sync(&devfreq->work);
 618                 return;
 619         }
 620
 621         /* if current delay is zero, start polling with new delay */
 622         if (!cur_delay) {
 623                 queue_delayed_work(devfreq_wq, &devfreq->work,
 624                         msecs_to_jiffies(devfreq->profile->polling_ms));
 625                 goto out;
 626         }
 627
 628         /* if current delay is greater than new delay, restart polling */
 629         if (cur_delay > new_delay) {
 630                 mutex_unlock(&devfreq->lock);
 631                 cancel_delayed_work_sync(&devfreq->work);
 632                 mutex_lock(&devfreq->lock);
 633                 if (!devfreq->stop_polling)
 634                         queue_delayed_work(devfreq_wq, &devfreq->work,
 635                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 636         }
 637 out:
 638         mutex_unlock(&devfreq->lock);
 639 }
 640 EXPORT_SYMBOL(devfreq_update_interval);
 641
 642 /**
 643  * devfreq_notifier_call() - Notify that the device frequency requirements
 644  *                           has been changed out of devfreq framework.
 645  * @nb:         the notifier_block (supposed to be devfreq->nb)
 646  * @type:       not used
 647  * @devp:       not used
 648  *
 649  * Called by a notifier that uses devfreq->nb.
 650  */
 651 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 652                                  void *devp)
 653 {
 654         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 655         int err = -EINVAL;
 656
 657         mutex_lock(&devfreq->lock);
 658
 659         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 660         if (!devfreq->scaling_min_freq)
 661                 goto out;
 662
 663         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 664         if (!devfreq->scaling_max_freq) {
 665                 devfreq->scaling_max_freq = ULONG_MAX;
 666                 goto out;
 667         }
 668
 669         err = update_devfreq(devfreq);
 670
 671 out:
 672         mutex_unlock(&devfreq->lock);
 673         if (err)
 674                 dev_err(devfreq->dev.parent,
 675                         "failed to update frequency from OPP notifier (%d)\n",
 676                         err);
 677
 678         return NOTIFY_OK;
 679 }
 680
 681 /**
 682  * qos_notifier_call() - Common handler for QoS constraints.
 683  * @devfreq:    the devfreq instance.
 684  */
 685 static int qos_notifier_call(struct devfreq *devfreq)
 686 {
 687         int err;
 688
 689         mutex_lock(&devfreq->lock);
 690         err = update_devfreq(devfreq);
 691         mutex_unlock(&devfreq->lock);
 692         if (err)
 693                 dev_err(devfreq->dev.parent,
 694                         "failed to update frequency from PM QoS (%d)\n",
 695                         err);
 696
 697         return NOTIFY_OK;
 698 }
 699
 700 /**
 701  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 702  * @nb:         Should be devfreq->nb_min
 703  */
 704 static int qos_min_notifier_call(struct notifier_block *nb,
 705                                          unsigned long val, void *ptr)
 706 {
 707         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 708 }
 709
 710 /**
 711  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 712  * @nb:         Should be devfreq->nb_max
 713  */
 714 static int qos_max_notifier_call(struct notifier_block *nb,
 715                                          unsigned long val, void *ptr)
 716 {
 717         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 718 }
 719
 720 /**
 721  * devfreq_dev_release() - Callback for struct device to release the device.
 722  * @dev:        the devfreq device
 723  *
 724  * Remove devfreq from the list and release its resources.
 725  */
 726 static void devfreq_dev_release(struct device *dev)
 727 {
 728         struct devfreq *devfreq = to_devfreq(dev);
 729         int err;
 730
 731         mutex_lock(&devfreq_list_lock);
 732         list_del(&devfreq->node);
 733         mutex_unlock(&devfreq_list_lock);
 734
 735         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 736                                          DEV_PM_QOS_MAX_FREQUENCY);
 737         if (err && err != -ENOENT)
 738                 dev_warn(dev->parent,
 739                         "Failed to remove max_freq notifier: %d\n", err);
 740         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 741                                          DEV_PM_QOS_MIN_FREQUENCY);
 742         if (err && err != -ENOENT)
 743                 dev_warn(dev->parent,
 744                         "Failed to remove min_freq notifier: %d\n", err);
 745
 746         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 747                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 748                 if (err < 0)
 749                         dev_warn(dev->parent,
 750                                 "Failed to remove max_freq request: %d\n", err);
 751         }
 752         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 753                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 754                 if (err < 0)
 755                         dev_warn(dev->parent,
 756                                 "Failed to remove min_freq request: %d\n", err);
 757         }
 758
 759         if (devfreq->profile->exit)
 760                 devfreq->profile->exit(devfreq->dev.parent);
 761
 762         if (devfreq->opp_table)
 763                 dev_pm_opp_put_opp_table(devfreq->opp_table);
 764
 765         mutex_destroy(&devfreq->lock);
 766         kfree(devfreq);
 767 }
 768
 769 static void create_sysfs_files(struct devfreq *devfreq,
 770                                 const struct devfreq_governor *gov);
 771 static void remove_sysfs_files(struct devfreq *devfreq,
 772                                 const struct devfreq_governor *gov);
 773
 774 /**
 775  * devfreq_add_device() - Add devfreq feature to the device
 776  * @dev:        the device to add devfreq feature.
 777  * @profile:    device-specific profile to run devfreq.
 778  * @governor_name:      name of the policy to choose frequency.
 779  * @data:       private data for the governor. The devfreq framework does not
 780  *              touch this value.
 781  */
 782 struct devfreq *devfreq_add_device(struct device *dev,
 783                                    struct devfreq_dev_profile *profile,
 784                                    const char *governor_name,
 785                                    void *data)
 786 {
 787         struct devfreq *devfreq;
 788         struct devfreq_governor *governor;
 789         unsigned long min_freq, max_freq;
 790         int err = 0;
 791
 792         if (!dev || !profile || !governor_name) {
 793                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 794                 return ERR_PTR(-EINVAL);
 795         }
 796
 797         mutex_lock(&devfreq_list_lock);
 798         devfreq = find_device_devfreq(dev);
 799         mutex_unlock(&devfreq_list_lock);
 800         if (!IS_ERR(devfreq)) {
 801                 dev_err(dev, "%s: devfreq device already exists!\n",
 802                         __func__);
 803                 err = -EINVAL;
 804                 goto err_out;
 805         }
 806
 807         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 808         if (!devfreq) {
 809                 err = -ENOMEM;
 810                 goto err_out;
 811         }
 812
 813         mutex_init(&devfreq->lock);
 814         mutex_lock(&devfreq->lock);
 815         devfreq->dev.parent = dev;
 816         devfreq->dev.class = devfreq_class;
 817         devfreq->dev.release = devfreq_dev_release;
 818         INIT_LIST_HEAD(&devfreq->node);
 819         devfreq->profile = profile;
 820         devfreq->previous_freq = profile->initial_freq;
 821         devfreq->last_status.current_frequency = profile->initial_freq;
 822         devfreq->data = data;
 823         devfreq->nb.notifier_call = devfreq_notifier_call;
 824
 825         if (devfreq->profile->timer < 0
 826                 || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 827                 mutex_unlock(&devfreq->lock);
 828                 err = -EINVAL;
 829                 goto err_dev;
 830         }
 831
 832         if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
 833                 mutex_unlock(&devfreq->lock);
 834                 err = set_freq_table(devfreq);
 835                 if (err < 0)
 836                         goto err_dev;
 837                 mutex_lock(&devfreq->lock);
 838         }
 839
 840         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 841         if (!devfreq->scaling_min_freq) {
 842                 mutex_unlock(&devfreq->lock);
 843                 err = -EINVAL;
 844                 goto err_dev;
 845         }
 846
 847         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 848         if (!devfreq->scaling_max_freq) {
 849                 mutex_unlock(&devfreq->lock);
 850                 err = -EINVAL;
 851                 goto err_dev;
 852         }
 853
 854         devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 855
 856         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 857         devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
 858         if (IS_ERR(devfreq->opp_table))
 859                 devfreq->opp_table = NULL;
 860
 861         atomic_set(&devfreq->suspend_count, 0);
 862
 863         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 864         err = device_register(&devfreq->dev);
 865         if (err) {
 866                 mutex_unlock(&devfreq->lock);
 867                 put_device(&devfreq->dev);
 868                 goto err_out;
 869         }
 870
 871         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 872                         array3_size(sizeof(unsigned int),
 873                                     devfreq->profile->max_state,
 874                                     devfreq->profile->max_state),
 875                         GFP_KERNEL);
 876         if (!devfreq->stats.trans_table) {
 877                 mutex_unlock(&devfreq->lock);
 878                 err = -ENOMEM;
 879                 goto err_devfreq;
 880         }
 881
 882         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 883                         devfreq->profile->max_state,
 884                         sizeof(*devfreq->stats.time_in_state),
 885                         GFP_KERNEL);
 886         if (!devfreq->stats.time_in_state) {
 887                 mutex_unlock(&devfreq->lock);
 888                 err = -ENOMEM;
 889                 goto err_devfreq;
 890         }
 891
 892         devfreq->stats.total_trans = 0;
 893         devfreq->stats.last_update = get_jiffies_64();
 894
 895         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 896
 897         mutex_unlock(&devfreq->lock);
 898
 899         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 900                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 901         if (err < 0)
 902                 goto err_devfreq;
 903         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 904                                      DEV_PM_QOS_MAX_FREQUENCY,
 905                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 906         if (err < 0)
 907                 goto err_devfreq;
 908
 909         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 910         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
 911                                       DEV_PM_QOS_MIN_FREQUENCY);
 912         if (err)
 913                 goto err_devfreq;
 914
 915         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 916         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
 917                                       DEV_PM_QOS_MAX_FREQUENCY);
 918         if (err)
 919                 goto err_devfreq;
 920
 921         mutex_lock(&devfreq_list_lock);
 922
 923         governor = try_then_request_governor(governor_name);
 924         if (IS_ERR(governor)) {
 925                 dev_err(dev, "%s: Unable to find governor for the device\n",
 926                         __func__);
 927                 err = PTR_ERR(governor);
 928                 goto err_init;
 929         }
 930
 931         devfreq->governor = governor;
 932         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 933                                                 NULL);
 934         if (err) {
 935                 dev_err(dev, "%s: Unable to start governor for the device\n",
 936                         __func__);
 937                 goto err_init;
 938         }
 939         create_sysfs_files(devfreq, devfreq->governor);
 940
 941         list_add(&devfreq->node, &devfreq_list);
 942
 943         mutex_unlock(&devfreq_list_lock);
 944
 945         if (devfreq->profile->is_cooling_device) {
 946                 devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
 947                 if (IS_ERR(devfreq->cdev))
 948                         devfreq->cdev = NULL;
 949         }
 950
 951         return devfreq;
 952
 953 err_init:
 954         mutex_unlock(&devfreq_list_lock);
 955 err_devfreq:
 956         devfreq_remove_device(devfreq);
 957         devfreq = NULL;
 958 err_dev:
 959         kfree(devfreq);
 960 err_out:
 961         return ERR_PTR(err);
 962 }
 963 EXPORT_SYMBOL(devfreq_add_device);
 964
 965 /**
 966  * devfreq_remove_device() - Remove devfreq feature from a device.
 967  * @devfreq:    the devfreq instance to be removed
 968  *
 969  * The opposite of devfreq_add_device().
 970  */
 971 int devfreq_remove_device(struct devfreq *devfreq)
 972 {
 973         if (!devfreq)
 974                 return -EINVAL;
 975
 976         devfreq_cooling_unregister(devfreq->cdev);
 977
 978         if (devfreq->governor) {
 979                 devfreq->governor->event_handler(devfreq,
 980                                                  DEVFREQ_GOV_STOP, NULL);
 981                 remove_sysfs_files(devfreq, devfreq->governor);
 982         }
 983
 984         device_unregister(&devfreq->dev);
 985
 986         return 0;
 987 }
 988 EXPORT_SYMBOL(devfreq_remove_device);
 989
 990 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 991 {
 992         struct devfreq **r = res;
 993
 994         if (WARN_ON(!r || !*r))
 995                 return 0;
 996
 997         return *r == data;
 998 }
 999
1000 static void devm_devfreq_dev_release(struct device *dev, void *res)
1001 {
1002         devfreq_remove_device(*(struct devfreq **)res);
1003 }
1004
1005 /**
1006  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
1007  * @dev:        the device to add devfreq feature.
1008  * @profile:    device-specific profile to run devfreq.
1009  * @governor_name:      name of the policy to choose frequency.
1010  * @data:       private data for the governor. The devfreq framework does not
1011  *              touch this value.
1012  *
1013  * This function manages automatically the memory of devfreq device using device
1014  * resource management and simplify the free operation for memory of devfreq
1015  * device.
1016  */
1017 struct devfreq *devm_devfreq_add_device(struct device *dev,
1018                                         struct devfreq_dev_profile *profile,
1019                                         const char *governor_name,
1020                                         void *data)
1021 {
1022         struct devfreq **ptr, *devfreq;
1023
1024         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
1025         if (!ptr)
1026                 return ERR_PTR(-ENOMEM);
1027
1028         devfreq = devfreq_add_device(dev, profile, governor_name, data);
1029         if (IS_ERR(devfreq)) {
1030                 devres_free(ptr);
1031                 return devfreq;
1032         }
1033
1034         *ptr = devfreq;
1035         devres_add(dev, ptr);
1036
1037         return devfreq;
1038 }
1039 EXPORT_SYMBOL(devm_devfreq_add_device);
1040
1041 #ifdef CONFIG_OF
1042 /*
1043  * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1044  * @node - pointer to device_node
1045  *
1046  * return the instance of devfreq device
1047  */
1048 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1049 {
1050         struct devfreq *devfreq;
1051
1052         if (!node)
1053                 return ERR_PTR(-EINVAL);
1054
1055         mutex_lock(&devfreq_list_lock);
1056         list_for_each_entry(devfreq, &devfreq_list, node) {
1057                 if (devfreq->dev.parent
1058                         && devfreq->dev.parent->of_node == node) {
1059                         mutex_unlock(&devfreq_list_lock);
1060                         return devfreq;
1061                 }
1062         }
1063         mutex_unlock(&devfreq_list_lock);
1064
1065         return ERR_PTR(-ENODEV);
1066 }
1067
1068 /*
1069  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1070  * @dev - instance to the given device
1071  * @phandle_name - name of property holding a phandle value
1072  * @index - index into list of devfreq
1073  *
1074  * return the instance of devfreq device
1075  */
1076 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1077                                         const char *phandle_name, int index)
1078 {
1079         struct device_node *node;
1080         struct devfreq *devfreq;
1081
1082         if (!dev || !phandle_name)
1083                 return ERR_PTR(-EINVAL);
1084
1085         if (!dev->of_node)
1086                 return ERR_PTR(-EINVAL);
1087
1088         node = of_parse_phandle(dev->of_node, phandle_name, index);
1089         if (!node)
1090                 return ERR_PTR(-ENODEV);
1091
1092         devfreq = devfreq_get_devfreq_by_node(node);
1093         of_node_put(node);
1094
1095         return devfreq;
1096 }
1097
1098 #else
1099 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1100 {
1101         return ERR_PTR(-ENODEV);
1102 }
1103
1104 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1105                                         const char *phandle_name, int index)
1106 {
1107         return ERR_PTR(-ENODEV);
1108 }
1109 #endif /* CONFIG_OF */
1110 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1111 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1112
1113 /**
1114  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1115  * @dev:        the device from which to remove devfreq feature.
1116  * @devfreq:    the devfreq instance to be removed
1117  */
1118 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1119 {
1120         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1121                                devm_devfreq_dev_match, devfreq));
1122 }
1123 EXPORT_SYMBOL(devm_devfreq_remove_device);
1124
1125 /**
1126  * devfreq_suspend_device() - Suspend devfreq of a device.
1127  * @devfreq: the devfreq instance to be suspended
1128  *
1129  * This function is intended to be called by the pm callbacks
1130  * (e.g., runtime_suspend, suspend) of the device driver that
1131  * holds the devfreq.
1132  */
1133 int devfreq_suspend_device(struct devfreq *devfreq)
1134 {
1135         int ret;
1136
1137         if (!devfreq)
1138                 return -EINVAL;
1139
1140         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1141                 return 0;
1142
1143         if (devfreq->governor) {
1144                 ret = devfreq->governor->event_handler(devfreq,
1145                                         DEVFREQ_GOV_SUSPEND, NULL);
1146                 if (ret)
1147                         return ret;
1148         }
1149
1150         if (devfreq->suspend_freq) {
1151                 mutex_lock(&devfreq->lock);
1152                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1153                 mutex_unlock(&devfreq->lock);
1154                 if (ret)
1155                         return ret;
1156         }
1157
1158         return 0;
1159 }
1160 EXPORT_SYMBOL(devfreq_suspend_device);
1161
1162 /**
1163  * devfreq_resume_device() - Resume devfreq of a device.
1164  * @devfreq: the devfreq instance to be resumed
1165  *
1166  * This function is intended to be called by the pm callbacks
1167  * (e.g., runtime_resume, resume) of the device driver that
1168  * holds the devfreq.
1169  */
1170 int devfreq_resume_device(struct devfreq *devfreq)
1171 {
1172         int ret;
1173
1174         if (!devfreq)
1175                 return -EINVAL;
1176
1177         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1178                 return 0;
1179
1180         if (devfreq->resume_freq) {
1181                 mutex_lock(&devfreq->lock);
1182                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1183                 mutex_unlock(&devfreq->lock);
1184                 if (ret)
1185                         return ret;
1186         }
1187
1188         if (devfreq->governor) {
1189                 ret = devfreq->governor->event_handler(devfreq,
1190                                         DEVFREQ_GOV_RESUME, NULL);
1191                 if (ret)
1192                         return ret;
1193         }
1194
1195         return 0;
1196 }
1197 EXPORT_SYMBOL(devfreq_resume_device);
1198
1199 /**
1200  * devfreq_suspend() - Suspend devfreq governors and devices
1201  *
1202  * Called during system wide Suspend/Hibernate cycles for suspending governors
1203  * and devices preserving the state for resume. On some platforms the devfreq
1204  * device must have precise state (frequency) after resume in order to provide
1205  * fully operating setup.
1206  */
1207 void devfreq_suspend(void)
1208 {
1209         struct devfreq *devfreq;
1210         int ret;
1211
1212         mutex_lock(&devfreq_list_lock);
1213         list_for_each_entry(devfreq, &devfreq_list, node) {
1214                 ret = devfreq_suspend_device(devfreq);
1215                 if (ret)
1216                         dev_err(&devfreq->dev,
1217                                 "failed to suspend devfreq device\n");
1218         }
1219         mutex_unlock(&devfreq_list_lock);
1220 }
1221
1222 /**
1223  * devfreq_resume() - Resume devfreq governors and devices
1224  *
1225  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1226  * devices that are suspended with devfreq_suspend().
1227  */
1228 void devfreq_resume(void)
1229 {
1230         struct devfreq *devfreq;
1231         int ret;
1232
1233         mutex_lock(&devfreq_list_lock);
1234         list_for_each_entry(devfreq, &devfreq_list, node) {
1235                 ret = devfreq_resume_device(devfreq);
1236                 if (ret)
1237                         dev_warn(&devfreq->dev,
1238                                  "failed to resume devfreq device\n");
1239         }
1240         mutex_unlock(&devfreq_list_lock);
1241 }
1242
1243 /**
1244  * devfreq_add_governor() - Add devfreq governor
1245  * @governor:   the devfreq governor to be added
1246  */
1247 int devfreq_add_governor(struct devfreq_governor *governor)
1248 {
1249         struct devfreq_governor *g;
1250         struct devfreq *devfreq;
1251         int err = 0;
1252
1253         if (!governor) {
1254                 pr_err("%s: Invalid parameters.\n", __func__);
1255                 return -EINVAL;
1256         }
1257
1258         mutex_lock(&devfreq_list_lock);
1259         g = find_devfreq_governor(governor->name);
1260         if (!IS_ERR(g)) {
1261                 pr_err("%s: governor %s already registered\n", __func__,
1262                        g->name);
1263                 err = -EINVAL;
1264                 goto err_out;
1265         }
1266
1267         list_add(&governor->node, &devfreq_governor_list);
1268
1269         list_for_each_entry(devfreq, &devfreq_list, node) {
1270                 int ret = 0;
1271                 struct device *dev = devfreq->dev.parent;
1272
1273                 if (!strncmp(devfreq->governor->name, governor->name,
1274                              DEVFREQ_NAME_LEN)) {
1275                         /* The following should never occur */
1276                         if (devfreq->governor) {
1277                                 dev_warn(dev,
1278                                          "%s: Governor %s already present\n",
1279                                          __func__, devfreq->governor->name);
1280                                 ret = devfreq->governor->event_handler(devfreq,
1281                                                         DEVFREQ_GOV_STOP, NULL);
1282                                 if (ret) {
1283                                         dev_warn(dev,
1284                                                  "%s: Governor %s stop = %d\n",
1285                                                  __func__,
1286                                                  devfreq->governor->name, ret);
1287                                 }
1288                                 /* Fall through */
1289                         }
1290                         devfreq->governor = governor;
1291                         ret = devfreq->governor->event_handler(devfreq,
1292                                                 DEVFREQ_GOV_START, NULL);
1293                         if (ret) {
1294                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1295                                          __func__, devfreq->governor->name,
1296                                          ret);
1297                         }
1298                 }
1299         }
1300
1301 err_out:
1302         mutex_unlock(&devfreq_list_lock);
1303
1304         return err;
1305 }
1306 EXPORT_SYMBOL(devfreq_add_governor);
1307
1308 static void devm_devfreq_remove_governor(void *governor)
1309 {
1310         WARN_ON(devfreq_remove_governor(governor));
1311 }
1312
1313 /**
1314  * devm_devfreq_add_governor() - Add devfreq governor
1315  * @dev:        device which adds devfreq governor
1316  * @governor:   the devfreq governor to be added
1317  *
1318  * This is a resource-managed variant of devfreq_add_governor().
1319  */
1320 int devm_devfreq_add_governor(struct device *dev,
1321                               struct devfreq_governor *governor)
1322 {
1323         int err;
1324
1325         err = devfreq_add_governor(governor);
1326         if (err)
1327                 return err;
1328
1329         return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
1330                                         governor);
1331 }
1332 EXPORT_SYMBOL(devm_devfreq_add_governor);
1333
1334 /**
1335  * devfreq_remove_governor() - Remove devfreq feature from a device.
1336  * @governor:   the devfreq governor to be removed
1337  */
1338 int devfreq_remove_governor(struct devfreq_governor *governor)
1339 {
1340         struct devfreq_governor *g;
1341         struct devfreq *devfreq;
1342         int err = 0;
1343
1344         if (!governor) {
1345                 pr_err("%s: Invalid parameters.\n", __func__);
1346                 return -EINVAL;
1347         }
1348
1349         mutex_lock(&devfreq_list_lock);
1350         g = find_devfreq_governor(governor->name);
1351         if (IS_ERR(g)) {
1352                 pr_err("%s: governor %s not registered\n", __func__,
1353                        governor->name);
1354                 err = PTR_ERR(g);
1355                 goto err_out;
1356         }
1357         list_for_each_entry(devfreq, &devfreq_list, node) {
1358                 int ret;
1359                 struct device *dev = devfreq->dev.parent;
1360
1361                 if (!strncmp(devfreq->governor->name, governor->name,
1362                              DEVFREQ_NAME_LEN)) {
1363                         /* we should have a devfreq governor! */
1364                         if (!devfreq->governor) {
1365                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1366                                          __func__, governor->name);
1367                                 continue;
1368                                 /* Fall through */
1369                         }
1370                         ret = devfreq->governor->event_handler(devfreq,
1371                                                 DEVFREQ_GOV_STOP, NULL);
1372                         if (ret) {
1373                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1374                                          __func__, devfreq->governor->name,
1375                                          ret);
1376                         }
1377                         devfreq->governor = NULL;
1378                 }
1379         }
1380
1381         list_del(&governor->node);
1382 err_out:
1383         mutex_unlock(&devfreq_list_lock);
1384
1385         return err;
1386 }
1387 EXPORT_SYMBOL(devfreq_remove_governor);
1388
1389 static ssize_t name_show(struct device *dev,
1390                         struct device_attribute *attr, char *buf)
1391 {
1392         struct devfreq *df = to_devfreq(dev);
1393         return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1394 }
1395 static DEVICE_ATTR_RO(name);
1396
1397 static ssize_t governor_show(struct device *dev,
1398                              struct device_attribute *attr, char *buf)
1399 {
1400         struct devfreq *df = to_devfreq(dev);
1401
1402         if (!df->governor)
1403                 return -EINVAL;
1404
1405         return sprintf(buf, "%s\n", df->governor->name);
1406 }
1407
1408 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1409                               const char *buf, size_t count)
1410 {
1411         struct devfreq *df = to_devfreq(dev);
1412         int ret;
1413         char str_governor[DEVFREQ_NAME_LEN + 1];
1414         const struct devfreq_governor *governor, *prev_governor;
1415
1416         if (!df->governor)
1417                 return -EINVAL;
1418
1419         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1420         if (ret != 1)
1421                 return -EINVAL;
1422
1423         mutex_lock(&devfreq_list_lock);
1424         governor = try_then_request_governor(str_governor);
1425         if (IS_ERR(governor)) {
1426                 ret = PTR_ERR(governor);
1427                 goto out;
1428         }
1429         if (df->governor == governor) {
1430                 ret = 0;
1431                 goto out;
1432         } else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
1433                 || IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
1434                 ret = -EINVAL;
1435                 goto out;
1436         }
1437
1438         /*
1439          * Stop the current governor and remove the specific sysfs files
1440          * which depend on current governor.
1441          */
1442         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1443         if (ret) {
1444                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1445                          __func__, df->governor->name, ret);
1446                 goto out;
1447         }
1448         remove_sysfs_files(df, df->governor);
1449
1450         /*
1451          * Start the new governor and create the specific sysfs files
1452          * which depend on the new governor.
1453          */
1454         prev_governor = df->governor;
1455         df->governor = governor;
1456         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1457         if (ret) {
1458                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1459                          __func__, df->governor->name, ret);
1460
1461                 /* Restore previous governor */
1462                 df->governor = prev_governor;
1463                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1464                 if (ret) {
1465                         dev_err(dev,
1466                                 "%s: reverting to Governor %s failed (%d)\n",
1467                                 __func__, prev_governor->name, ret);
1468                         df->governor = NULL;
1469                         goto out;
1470                 }
1471         }
1472
1473         /*
1474          * Create the sysfs files for the new governor. But if failed to start
1475          * the new governor, restore the sysfs files of previous governor.
1476          */
1477         create_sysfs_files(df, df->governor);
1478
1479 out:
1480         mutex_unlock(&devfreq_list_lock);
1481
1482         if (!ret)
1483                 ret = count;
1484         return ret;
1485 }
1486 static DEVICE_ATTR_RW(governor);
1487
1488 static ssize_t available_governors_show(struct device *d,
1489                                         struct device_attribute *attr,
1490                                         char *buf)
1491 {
1492         struct devfreq *df = to_devfreq(d);
1493         ssize_t count = 0;
1494
1495         if (!df->governor)
1496                 return -EINVAL;
1497
1498         mutex_lock(&devfreq_list_lock);
1499
1500         /*
1501          * The devfreq with immutable governor (e.g., passive) shows
1502          * only own governor.
1503          */
1504         if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
1505                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1506                                   "%s ", df->governor->name);
1507         /*
1508          * The devfreq device shows the registered governor except for
1509          * immutable governors such as passive governor .
1510          */
1511         } else {
1512                 struct devfreq_governor *governor;
1513
1514                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1515                         if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
1516                                 continue;
1517                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1518                                            "%s ", governor->name);
1519                 }
1520         }
1521
1522         mutex_unlock(&devfreq_list_lock);
1523
1524         /* Truncate the trailing space */
1525         if (count)
1526                 count--;
1527
1528         count += sprintf(&buf[count], "\n");
1529
1530         return count;
1531 }
1532 static DEVICE_ATTR_RO(available_governors);
1533
1534 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1535                              char *buf)
1536 {
1537         unsigned long freq;
1538         struct devfreq *df = to_devfreq(dev);
1539
1540         if (!df->profile)
1541                 return -EINVAL;
1542
1543         if (df->profile->get_cur_freq &&
1544                 !df->profile->get_cur_freq(df->dev.parent, &freq))
1545                 return sprintf(buf, "%lu\n", freq);
1546
1547         return sprintf(buf, "%lu\n", df->previous_freq);
1548 }
1549 static DEVICE_ATTR_RO(cur_freq);
1550
1551 static ssize_t target_freq_show(struct device *dev,
1552                                 struct device_attribute *attr, char *buf)
1553 {
1554         struct devfreq *df = to_devfreq(dev);
1555
1556         return sprintf(buf, "%lu\n", df->previous_freq);
1557 }
1558 static DEVICE_ATTR_RO(target_freq);
1559
1560 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1561                               const char *buf, size_t count)
1562 {
1563         struct devfreq *df = to_devfreq(dev);
1564         unsigned long value;
1565         int ret;
1566
1567         /*
1568          * Protect against theoretical sysfs writes between
1569          * device_add and dev_pm_qos_add_request
1570          */
1571         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1572                 return -EAGAIN;
1573
1574         ret = sscanf(buf, "%lu", &value);
1575         if (ret != 1)
1576                 return -EINVAL;
1577
1578         /* Round down to kHz for PM QoS */
1579         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1580                                         value / HZ_PER_KHZ);
1581         if (ret < 0)
1582                 return ret;
1583
1584         return count;
1585 }
1586
1587 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1588                              char *buf)
1589 {
1590         struct devfreq *df = to_devfreq(dev);
1591         unsigned long min_freq, max_freq;
1592
1593         mutex_lock(&df->lock);
1594         devfreq_get_freq_range(df, &min_freq, &max_freq);
1595         mutex_unlock(&df->lock);
1596
1597         return sprintf(buf, "%lu\n", min_freq);
1598 }
1599 static DEVICE_ATTR_RW(min_freq);
1600
1601 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1602                               const char *buf, size_t count)
1603 {
1604         struct devfreq *df = to_devfreq(dev);
1605         unsigned long value;
1606         int ret;
1607
1608         /*
1609          * Protect against theoretical sysfs writes between
1610          * device_add and dev_pm_qos_add_request
1611          */
1612         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1613                 return -EINVAL;
1614
1615         ret = sscanf(buf, "%lu", &value);
1616         if (ret != 1)
1617                 return -EINVAL;
1618
1619         /*
1620          * PM QoS frequencies are in kHz so we need to convert. Convert by
1621          * rounding upwards so that the acceptable interval never shrinks.
1622          *
1623          * For example if the user writes "666666666" to sysfs this value will
1624          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1625          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1626          *
1627          * A value of zero means "no limit".
1628          */
1629         if (value)
1630                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1631         else
1632                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1633
1634         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1635         if (ret < 0)
1636                 return ret;
1637
1638         return count;
1639 }
1640
1641 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1642                              char *buf)
1643 {
1644         struct devfreq *df = to_devfreq(dev);
1645         unsigned long min_freq, max_freq;
1646
1647         mutex_lock(&df->lock);
1648         devfreq_get_freq_range(df, &min_freq, &max_freq);
1649         mutex_unlock(&df->lock);
1650
1651         return sprintf(buf, "%lu\n", max_freq);
1652 }
1653 static DEVICE_ATTR_RW(max_freq);
1654
1655 static ssize_t available_frequencies_show(struct device *d,
1656                                           struct device_attribute *attr,
1657                                           char *buf)
1658 {
1659         struct devfreq *df = to_devfreq(d);
1660         ssize_t count = 0;
1661         int i;
1662
1663         if (!df->profile)
1664                 return -EINVAL;
1665
1666         mutex_lock(&df->lock);
1667
1668         for (i = 0; i < df->profile->max_state; i++)
1669                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1670                                 "%lu ", df->profile->freq_table[i]);
1671
1672         mutex_unlock(&df->lock);
1673         /* Truncate the trailing space */
1674         if (count)
1675                 count--;
1676
1677         count += sprintf(&buf[count], "\n");
1678
1679         return count;
1680 }
1681 static DEVICE_ATTR_RO(available_frequencies);
1682
1683 static ssize_t trans_stat_show(struct device *dev,
1684                                struct device_attribute *attr, char *buf)
1685 {
1686         struct devfreq *df = to_devfreq(dev);
1687         ssize_t len;
1688         int i, j;
1689         unsigned int max_state;
1690
1691         if (!df->profile)
1692                 return -EINVAL;
1693         max_state = df->profile->max_state;
1694
1695         if (max_state == 0)
1696                 return sprintf(buf, "Not Supported.\n");
1697
1698         mutex_lock(&df->lock);
1699         if (!df->stop_polling &&
1700                         devfreq_update_status(df, df->previous_freq)) {
1701                 mutex_unlock(&df->lock);
1702                 return 0;
1703         }
1704         mutex_unlock(&df->lock);
1705
1706         len = sprintf(buf, "     From  :   To\n");
1707         len += sprintf(buf + len, "           :");
1708         for (i = 0; i < max_state; i++)
1709                 len += sprintf(buf + len, "%10lu",
1710                                 df->profile->freq_table[i]);
1711
1712         len += sprintf(buf + len, "   time(ms)\n");
1713
1714         for (i = 0; i < max_state; i++) {
1715                 if (df->profile->freq_table[i]
1716                                         == df->previous_freq) {
1717                         len += sprintf(buf + len, "*");
1718                 } else {
1719                         len += sprintf(buf + len, " ");
1720                 }
1721                 len += sprintf(buf + len, "%10lu:",
1722                                 df->profile->freq_table[i]);
1723                 for (j = 0; j < max_state; j++)
1724                         len += sprintf(buf + len, "%10u",
1725                                 df->stats.trans_table[(i * max_state) + j]);
1726
1727                 len += sprintf(buf + len, "%10llu\n", (u64)
1728                         jiffies64_to_msecs(df->stats.time_in_state[i]));
1729         }
1730
1731         len += sprintf(buf + len, "Total transition : %u\n",
1732                                         df->stats.total_trans);
1733         return len;
1734 }
1735
1736 static ssize_t trans_stat_store(struct device *dev,
1737                                 struct device_attribute *attr,
1738                                 const char *buf, size_t count)
1739 {
1740         struct devfreq *df = to_devfreq(dev);
1741         int err, value;
1742
1743         if (!df->profile)
1744                 return -EINVAL;
1745
1746         if (df->profile->max_state == 0)
1747                 return count;
1748
1749         err = kstrtoint(buf, 10, &value);
1750         if (err || value != 0)
1751                 return -EINVAL;
1752
1753         mutex_lock(&df->lock);
1754         memset(df->stats.time_in_state, 0, (df->profile->max_state *
1755                                         sizeof(*df->stats.time_in_state)));
1756         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1757                                         df->profile->max_state,
1758                                         df->profile->max_state));
1759         df->stats.total_trans = 0;
1760         df->stats.last_update = get_jiffies_64();
1761         mutex_unlock(&df->lock);
1762
1763         return count;
1764 }
1765 static DEVICE_ATTR_RW(trans_stat);
1766
1767 static struct attribute *devfreq_attrs[] = {
1768         &dev_attr_name.attr,
1769         &dev_attr_governor.attr,
1770         &dev_attr_available_governors.attr,
1771         &dev_attr_cur_freq.attr,
1772         &dev_attr_available_frequencies.attr,
1773         &dev_attr_target_freq.attr,
1774         &dev_attr_min_freq.attr,
1775         &dev_attr_max_freq.attr,
1776         &dev_attr_trans_stat.attr,
1777         NULL,
1778 };
1779 ATTRIBUTE_GROUPS(devfreq);
1780
1781 static ssize_t polling_interval_show(struct device *dev,
1782                                      struct device_attribute *attr, char *buf)
1783 {
1784         struct devfreq *df = to_devfreq(dev);
1785
1786         if (!df->profile)
1787                 return -EINVAL;
1788
1789         return sprintf(buf, "%d\n", df->profile->polling_ms);
1790 }
1791
1792 static ssize_t polling_interval_store(struct device *dev,
1793                                       struct device_attribute *attr,
1794                                       const char *buf, size_t count)
1795 {
1796         struct devfreq *df = to_devfreq(dev);
1797         unsigned int value;
1798         int ret;
1799
1800         if (!df->governor)
1801                 return -EINVAL;
1802
1803         ret = sscanf(buf, "%u", &value);
1804         if (ret != 1)
1805                 return -EINVAL;
1806
1807         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1808         ret = count;
1809
1810         return ret;
1811 }
1812 static DEVICE_ATTR_RW(polling_interval);
1813
1814 static ssize_t timer_show(struct device *dev,
1815                              struct device_attribute *attr, char *buf)
1816 {
1817         struct devfreq *df = to_devfreq(dev);
1818
1819         if (!df->profile)
1820                 return -EINVAL;
1821
1822         return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
1823 }
1824
1825 static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1826                               const char *buf, size_t count)
1827 {
1828         struct devfreq *df = to_devfreq(dev);
1829         char str_timer[DEVFREQ_NAME_LEN + 1];
1830         int timer = -1;
1831         int ret = 0, i;
1832
1833         if (!df->governor || !df->profile)
1834                 return -EINVAL;
1835
1836         ret = sscanf(buf, "%16s", str_timer);
1837         if (ret != 1)
1838                 return -EINVAL;
1839
1840         for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1841                 if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1842                         timer = i;
1843                         break;
1844                 }
1845         }
1846
1847         if (timer < 0) {
1848                 ret = -EINVAL;
1849                 goto out;
1850         }
1851
1852         if (df->profile->timer == timer) {
1853                 ret = 0;
1854                 goto out;
1855         }
1856
1857         mutex_lock(&df->lock);
1858         df->profile->timer = timer;
1859         mutex_unlock(&df->lock);
1860
1861         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1862         if (ret) {
1863                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1864                          __func__, df->governor->name, ret);
1865                 goto out;
1866         }
1867
1868         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1869         if (ret)
1870                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1871                          __func__, df->governor->name, ret);
1872 out:
1873         return ret ? ret : count;
1874 }
1875 static DEVICE_ATTR_RW(timer);
1876
1877 #define CREATE_SYSFS_FILE(df, name)                                     \
1878 {                                                                       \
1879         int ret;                                                        \
1880         ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);  \
1881         if (ret < 0) {                                                  \
1882                 dev_warn(&df->dev,                                      \
1883                         "Unable to create attr(%s)\n", "##name");       \
1884         }                                                               \
1885 }                                                                       \
1886
1887 /* Create the specific sysfs files which depend on each governor. */
1888 static void create_sysfs_files(struct devfreq *devfreq,
1889                                 const struct devfreq_governor *gov)
1890 {
1891         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1892                 CREATE_SYSFS_FILE(devfreq, polling_interval);
1893         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1894                 CREATE_SYSFS_FILE(devfreq, timer);
1895 }
1896
1897 /* Remove the specific sysfs files which depend on each governor. */
1898 static void remove_sysfs_files(struct devfreq *devfreq,
1899                                 const struct devfreq_governor *gov)
1900 {
1901         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1902                 sysfs_remove_file(&devfreq->dev.kobj,
1903                                 &dev_attr_polling_interval.attr);
1904         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1905                 sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
1906 }
1907
1908 /**
1909  * devfreq_summary_show() - Show the summary of the devfreq devices
1910  * @s:          seq_file instance to show the summary of devfreq devices
1911  * @data:       not used
1912  *
1913  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1914  * It helps that user can know the detailed information of the devfreq devices.
1915  *
1916  * Return 0 always because it shows the information without any data change.
1917  */
1918 static int devfreq_summary_show(struct seq_file *s, void *data)
1919 {
1920         struct devfreq *devfreq;
1921         struct devfreq *p_devfreq = NULL;
1922         unsigned long cur_freq, min_freq, max_freq;
1923         unsigned int polling_ms;
1924         unsigned int timer;
1925
1926         seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1927                         "dev",
1928                         "parent_dev",
1929                         "governor",
1930                         "timer",
1931                         "polling_ms",
1932                         "cur_freq_Hz",
1933                         "min_freq_Hz",
1934                         "max_freq_Hz");
1935         seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1936                         "------------------------------",
1937                         "------------------------------",
1938                         "---------------",
1939                         "----------",
1940                         "----------",
1941                         "------------",
1942                         "------------",
1943                         "------------");
1944
1945         mutex_lock(&devfreq_list_lock);
1946
1947         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1948 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1949                 if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
1950                                                         DEVFREQ_NAME_LEN)) {
1951                         struct devfreq_passive_data *data = devfreq->data;
1952
1953                         if (data)
1954                                 p_devfreq = data->parent;
1955                 } else {
1956                         p_devfreq = NULL;
1957                 }
1958 #endif
1959
1960                 mutex_lock(&devfreq->lock);
1961                 cur_freq = devfreq->previous_freq;
1962                 devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
1963                 timer = devfreq->profile->timer;
1964
1965                 if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
1966                         polling_ms = devfreq->profile->polling_ms;
1967                 else
1968                         polling_ms = 0;
1969                 mutex_unlock(&devfreq->lock);
1970
1971                 seq_printf(s,
1972                         "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
1973                         dev_name(&devfreq->dev),
1974                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1975                         devfreq->governor->name,
1976                         polling_ms ? timer_name[timer] : "null",
1977                         polling_ms,
1978                         cur_freq,
1979                         min_freq,
1980                         max_freq);
1981         }
1982
1983         mutex_unlock(&devfreq_list_lock);
1984
1985         return 0;
1986 }
1987 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1988
1989 static int __init devfreq_init(void)
1990 {
1991         devfreq_class = class_create(THIS_MODULE, "devfreq");
1992         if (IS_ERR(devfreq_class)) {
1993                 pr_err("%s: couldn't create class\n", __FILE__);
1994                 return PTR_ERR(devfreq_class);
1995         }
1996
1997         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1998         if (!devfreq_wq) {
1999                 class_destroy(devfreq_class);
2000                 pr_err("%s: couldn't create workqueue\n", __FILE__);
2001                 return -ENOMEM;
2002         }
2003         devfreq_class->dev_groups = devfreq_groups;
2004
2005         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
2006         debugfs_create_file("devfreq_summary", 0444,
2007                                 devfreq_debugfs, NULL,
2008                                 &devfreq_summary_fops);
2009
2010         return 0;
2011 }
2012 subsys_initcall(devfreq_init);
2013
2014 /*
2015  * The following are helper functions for devfreq user device drivers with
2016  * OPP framework.
2017  */
2018
2019 /**
2020  * devfreq_recommended_opp() - Helper function to get proper OPP for the
2021  *                           freq value given to target callback.
2022  * @dev:        The devfreq user device. (parent of devfreq)
2023  * @freq:       The frequency given to target function
2024  * @flags:      Flags handed from devfreq framework.
2025  *
2026  * The callers are required to call dev_pm_opp_put() for the returned OPP after
2027  * use.
2028  */
2029 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
2030                                            unsigned long *freq,
2031                                            u32 flags)
2032 {
2033         struct dev_pm_opp *opp;
2034
2035         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
2036                 /* The freq is an upper bound. opp should be lower */
2037                 opp = dev_pm_opp_find_freq_floor(dev, freq);
2038
2039                 /* If not available, use the closest opp */
2040                 if (opp == ERR_PTR(-ERANGE))
2041                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
2042         } else {
2043                 /* The freq is an lower bound. opp should be higher */
2044                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
2045
2046                 /* If not available, use the closest opp */
2047                 if (opp == ERR_PTR(-ERANGE))
2048                         opp = dev_pm_opp_find_freq_floor(dev, freq);
2049         }
2050
2051         return opp;
2052 }
2053 EXPORT_SYMBOL(devfreq_recommended_opp);
2054
2055 /**
2056  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
2057  *                                   for any changes in the OPP availability
2058  *                                   changes
2059  * @dev:        The devfreq user device. (parent of devfreq)
2060  * @devfreq:    The devfreq object.
2061  */
2062 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
2063 {
2064         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
2065 }
2066 EXPORT_SYMBOL(devfreq_register_opp_notifier);
2067
2068 /**
2069  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
2070  *                                     notified for any changes in the OPP
2071  *                                     availability changes anymore.
2072  * @dev:        The devfreq user device. (parent of devfreq)
2073  * @devfreq:    The devfreq object.
2074  *
2075  * At exit() callback of devfreq_dev_profile, this must be included if
2076  * devfreq_recommended_opp is used.
2077  */
2078 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
2079 {
2080         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
2081 }
2082 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
2083
2084 static void devm_devfreq_opp_release(struct device *dev, void *res)
2085 {
2086         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
2087 }
2088
2089 /**
2090  * devm_devfreq_register_opp_notifier() - Resource-managed
2091  *                                        devfreq_register_opp_notifier()
2092  * @dev:        The devfreq user device. (parent of devfreq)
2093  * @devfreq:    The devfreq object.
2094  */
2095 int devm_devfreq_register_opp_notifier(struct device *dev,
2096                                        struct devfreq *devfreq)
2097 {
2098         struct devfreq **ptr;
2099         int ret;
2100
2101         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
2102         if (!ptr)
2103                 return -ENOMEM;
2104
2105         ret = devfreq_register_opp_notifier(dev, devfreq);
2106         if (ret) {
2107                 devres_free(ptr);
2108                 return ret;
2109         }
2110
2111         *ptr = devfreq;
2112         devres_add(dev, ptr);
2113
2114         return 0;
2115 }
2116 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2117
2118 /**
2119  * devm_devfreq_unregister_opp_notifier() - Resource-managed
2120  *                                          devfreq_unregister_opp_notifier()
2121  * @dev:        The devfreq user device. (parent of devfreq)
2122  * @devfreq:    The devfreq object.
2123  */
2124 void devm_devfreq_unregister_opp_notifier(struct device *dev,
2125                                          struct devfreq *devfreq)
2126 {
2127         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2128                                devm_devfreq_dev_match, devfreq));
2129 }
2130 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2131
2132 /**
2133  * devfreq_register_notifier() - Register a driver with devfreq
2134  * @devfreq:    The devfreq object.
2135  * @nb:         The notifier block to register.
2136  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2137  */
2138 int devfreq_register_notifier(struct devfreq *devfreq,
2139                               struct notifier_block *nb,
2140                               unsigned int list)
2141 {
2142         int ret = 0;
2143
2144         if (!devfreq)
2145                 return -EINVAL;
2146
2147         switch (list) {
2148         case DEVFREQ_TRANSITION_NOTIFIER:
2149                 ret = srcu_notifier_chain_register(
2150                                 &devfreq->transition_notifier_list, nb);
2151                 break;
2152         default:
2153                 ret = -EINVAL;
2154         }
2155
2156         return ret;
2157 }
2158 EXPORT_SYMBOL(devfreq_register_notifier);
2159
2160 /*
2161  * devfreq_unregister_notifier() - Unregister a driver with devfreq
2162  * @devfreq:    The devfreq object.
2163  * @nb:         The notifier block to be unregistered.
2164  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2165  */
2166 int devfreq_unregister_notifier(struct devfreq *devfreq,
2167                                 struct notifier_block *nb,
2168                                 unsigned int list)
2169 {
2170         int ret = 0;
2171
2172         if (!devfreq)
2173                 return -EINVAL;
2174
2175         switch (list) {
2176         case DEVFREQ_TRANSITION_NOTIFIER:
2177                 ret = srcu_notifier_chain_unregister(
2178                                 &devfreq->transition_notifier_list, nb);
2179                 break;
2180         default:
2181                 ret = -EINVAL;
2182         }
2183
2184         return ret;
2185 }
2186 EXPORT_SYMBOL(devfreq_unregister_notifier);
2187
2188 struct devfreq_notifier_devres {
2189         struct devfreq *devfreq;
2190         struct notifier_block *nb;
2191         unsigned int list;
2192 };
2193
2194 static void devm_devfreq_notifier_release(struct device *dev, void *res)
2195 {
2196         struct devfreq_notifier_devres *this = res;
2197
2198         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2199 }
2200
2201 /**
2202  * devm_devfreq_register_notifier()
2203  *      - Resource-managed devfreq_register_notifier()
2204  * @dev:        The devfreq user device. (parent of devfreq)
2205  * @devfreq:    The devfreq object.
2206  * @nb:         The notifier block to be unregistered.
2207  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2208  */
2209 int devm_devfreq_register_notifier(struct device *dev,
2210                                 struct devfreq *devfreq,
2211                                 struct notifier_block *nb,
2212                                 unsigned int list)
2213 {
2214         struct devfreq_notifier_devres *ptr;
2215         int ret;
2216
2217         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2218                                 GFP_KERNEL);
2219         if (!ptr)
2220                 return -ENOMEM;
2221
2222         ret = devfreq_register_notifier(devfreq, nb, list);
2223         if (ret) {
2224                 devres_free(ptr);
2225                 return ret;
2226         }
2227
2228         ptr->devfreq = devfreq;
2229         ptr->nb = nb;
2230         ptr->list = list;
2231         devres_add(dev, ptr);
2232
2233         return 0;
2234 }
2235 EXPORT_SYMBOL(devm_devfreq_register_notifier);
2236
2237 /**
2238  * devm_devfreq_unregister_notifier()
2239  *      - Resource-managed devfreq_unregister_notifier()
2240  * @dev:        The devfreq user device. (parent of devfreq)
2241  * @devfreq:    The devfreq object.
2242  * @nb:         The notifier block to be unregistered.
2243  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2244  */
2245 void devm_devfreq_unregister_notifier(struct device *dev,
2246                                       struct devfreq *devfreq,
2247                                       struct notifier_block *nb,
2248                                       unsigned int list)
2249 {
2250         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2251                                devm_devfreq_dev_match, devfreq));
2252 }
2253 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);