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