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