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_indexed(devfreq->dev.parent, &min_freq, 0);
  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_indexed(devfreq->dev.parent, &max_freq, 0);
 106         if (IS_ERR(opp))
 107                 max_freq = 0;
 108         else
 109                 dev_pm_opp_put(opp);
 110
 111         return max_freq;
 112 }
 113
 114 /**
 115  * devfreq_get_freq_range() - Get the current freq range
 116  * @devfreq:    the devfreq instance
 117  * @min_freq:   the min frequency
 118  * @max_freq:   the max frequency
 119  *
 120  * This takes into consideration all constraints.
 121  */
 122 void devfreq_get_freq_range(struct devfreq *devfreq,
 123                             unsigned long *min_freq,
 124                             unsigned long *max_freq)
 125 {
 126         unsigned long *freq_table = devfreq->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->max_state - 1]) {
 137                 *min_freq = freq_table[0];
 138                 *max_freq = freq_table[devfreq->max_state - 1];
 139         } else {
 140                 *min_freq = freq_table[devfreq->max_state - 1];
 141                 *max_freq = freq_table[0];
 142         }
 143
 144         /* Apply constraints from PM QoS */
 145         qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 146                                              DEV_PM_QOS_MIN_FREQUENCY);
 147         qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 148                                              DEV_PM_QOS_MAX_FREQUENCY);
 149         *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 150         if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 151                 *max_freq = min(*max_freq,
 152                                 (unsigned long)HZ_PER_KHZ * qos_max_freq);
 153
 154         /* Apply constraints from OPP interface */
 155         *min_freq = max(*min_freq, devfreq->scaling_min_freq);
 156         *max_freq = min(*max_freq, devfreq->scaling_max_freq);
 157
 158         if (*min_freq > *max_freq)
 159                 *min_freq = *max_freq;
 160 }
 161 EXPORT_SYMBOL(devfreq_get_freq_range);
 162
 163 /**
 164  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 165  * @devfreq:    the devfreq instance
 166  * @freq:       the target frequency
 167  */
 168 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 169 {
 170         int lev;
 171
 172         for (lev = 0; lev < devfreq->max_state; lev++)
 173                 if (freq == devfreq->freq_table[lev])
 174                         return lev;
 175
 176         return -EINVAL;
 177 }
 178
 179 static int set_freq_table(struct devfreq *devfreq)
 180 {
 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         devfreq->max_state = count;
 191         devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
 192                                            devfreq->max_state,
 193                                            sizeof(*devfreq->freq_table),
 194                                            GFP_KERNEL);
 195         if (!devfreq->freq_table)
 196                 return -ENOMEM;
 197
 198         for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
 199                 opp = dev_pm_opp_find_freq_ceil_indexed(devfreq->dev.parent, &freq, 0);
 200                 if (IS_ERR(opp)) {
 201                         devm_kfree(devfreq->dev.parent, devfreq->freq_table);
 202                         return PTR_ERR(opp);
 203                 }
 204                 dev_pm_opp_put(opp);
 205                 devfreq->freq_table[i] = freq;
 206         }
 207
 208         return 0;
 209 }
 210
 211 /**
 212  * devfreq_update_status() - Update statistics of devfreq behavior
 213  * @devfreq:    the devfreq instance
 214  * @freq:       the update target frequency
 215  */
 216 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 217 {
 218         int lev, prev_lev, ret = 0;
 219         u64 cur_time;
 220
 221         lockdep_assert_held(&devfreq->lock);
 222         cur_time = get_jiffies_64();
 223
 224         /* Immediately exit if previous_freq is not initialized yet. */
 225         if (!devfreq->previous_freq)
 226                 goto out;
 227
 228         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 229         if (prev_lev < 0) {
 230                 ret = prev_lev;
 231                 goto out;
 232         }
 233
 234         devfreq->stats.time_in_state[prev_lev] +=
 235                         cur_time - devfreq->stats.last_update;
 236
 237         lev = devfreq_get_freq_level(devfreq, freq);
 238         if (lev < 0) {
 239                 ret = lev;
 240                 goto out;
 241         }
 242
 243         if (lev != prev_lev) {
 244                 devfreq->stats.trans_table[
 245                         (prev_lev * devfreq->max_state) + lev]++;
 246                 devfreq->stats.total_trans++;
 247         }
 248
 249 out:
 250         devfreq->stats.last_update = cur_time;
 251         return ret;
 252 }
 253 EXPORT_SYMBOL(devfreq_update_status);
 254
 255 /**
 256  * find_devfreq_governor() - find devfreq governor from name
 257  * @name:       name of the governor
 258  *
 259  * Search the list of devfreq governors and return the matched
 260  * governor's pointer. devfreq_list_lock should be held by the caller.
 261  */
 262 static struct devfreq_governor *find_devfreq_governor(const char *name)
 263 {
 264         struct devfreq_governor *tmp_governor;
 265
 266         lockdep_assert_held(&devfreq_list_lock);
 267
 268         if (IS_ERR_OR_NULL(name)) {
 269                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 270                 return ERR_PTR(-EINVAL);
 271         }
 272
 273         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 274                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 275                         return tmp_governor;
 276         }
 277
 278         return ERR_PTR(-ENODEV);
 279 }
 280
 281 /**
 282  * try_then_request_governor() - Try to find the governor and request the
 283  *                               module if is not found.
 284  * @name:       name of the governor
 285  *
 286  * Search the list of devfreq governors and request the module and try again
 287  * if is not found. This can happen when both drivers (the governor driver
 288  * and the driver that call devfreq_add_device) are built as modules.
 289  * devfreq_list_lock should be held by the caller. Returns the matched
 290  * governor's pointer or an error pointer.
 291  */
 292 static struct devfreq_governor *try_then_request_governor(const char *name)
 293 {
 294         struct devfreq_governor *governor;
 295         int err = 0;
 296
 297         lockdep_assert_held(&devfreq_list_lock);
 298
 299         if (IS_ERR_OR_NULL(name)) {
 300                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 301                 return ERR_PTR(-EINVAL);
 302         }
 303
 304         governor = find_devfreq_governor(name);
 305         if (IS_ERR(governor)) {
 306                 mutex_unlock(&devfreq_list_lock);
 307
 308                 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 309                              DEVFREQ_NAME_LEN))
 310                         err = request_module("governor_%s", "simpleondemand");
 311                 else
 312                         err = request_module("governor_%s", name);
 313                 /* Restore previous state before return */
 314                 mutex_lock(&devfreq_list_lock);
 315                 if (err)
 316                         return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 317
 318                 governor = find_devfreq_governor(name);
 319         }
 320
 321         return governor;
 322 }
 323
 324 static int devfreq_notify_transition(struct devfreq *devfreq,
 325                 struct devfreq_freqs *freqs, unsigned int state)
 326 {
 327         if (!devfreq)
 328                 return -EINVAL;
 329
 330         switch (state) {
 331         case DEVFREQ_PRECHANGE:
 332                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 333                                 DEVFREQ_PRECHANGE, freqs);
 334                 break;
 335
 336         case DEVFREQ_POSTCHANGE:
 337                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 338                                 DEVFREQ_POSTCHANGE, freqs);
 339                 break;
 340         default:
 341                 return -EINVAL;
 342         }
 343
 344         return 0;
 345 }
 346
 347 static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 348                               u32 flags)
 349 {
 350         struct devfreq_freqs freqs;
 351         unsigned long cur_freq;
 352         int err = 0;
 353
 354         if (devfreq->profile->get_cur_freq)
 355                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 356         else
 357                 cur_freq = devfreq->previous_freq;
 358
 359         freqs.old = cur_freq;
 360         freqs.new = new_freq;
 361         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 362
 363         err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 364         if (err) {
 365                 freqs.new = cur_freq;
 366                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 367                 return err;
 368         }
 369
 370         /*
 371          * Print devfreq_frequency trace information between DEVFREQ_PRECHANGE
 372          * and DEVFREQ_POSTCHANGE because for showing the correct frequency
 373          * change order of between devfreq device and passive devfreq device.
 374          */
 375         if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
 376                 trace_devfreq_frequency(devfreq, new_freq, cur_freq);
 377
 378         freqs.new = new_freq;
 379         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 380
 381         if (devfreq_update_status(devfreq, new_freq))
 382                 dev_warn(&devfreq->dev,
 383                          "Couldn't update frequency transition information.\n");
 384
 385         devfreq->previous_freq = new_freq;
 386
 387         if (devfreq->suspend_freq)
 388                 devfreq->resume_freq = new_freq;
 389
 390         return err;
 391 }
 392
 393 /**
 394  * devfreq_update_target() - Reevaluate the device and configure frequency
 395  *                         on the final stage.
 396  * @devfreq:    the devfreq instance.
 397  * @freq:       the new frequency of parent device. This argument
 398  *              is only used for devfreq device using passive governor.
 399  *
 400  * Note: Lock devfreq->lock before calling devfreq_update_target. This function
 401  *       should be only used by both update_devfreq() and devfreq governors.
 402  */
 403 int devfreq_update_target(struct devfreq *devfreq, unsigned long freq)
 404 {
 405         unsigned long min_freq, max_freq;
 406         int err = 0;
 407         u32 flags = 0;
 408
 409         lockdep_assert_held(&devfreq->lock);
 410
 411         if (!devfreq->governor)
 412                 return -EINVAL;
 413
 414         /* Reevaluate the proper frequency */
 415         err = devfreq->governor->get_target_freq(devfreq, &freq);
 416         if (err)
 417                 return err;
 418         devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 419
 420         if (freq < min_freq) {
 421                 freq = min_freq;
 422                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 423         }
 424         if (freq > max_freq) {
 425                 freq = max_freq;
 426                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 427         }
 428
 429         return devfreq_set_target(devfreq, freq, flags);
 430 }
 431 EXPORT_SYMBOL(devfreq_update_target);
 432
 433 /* Load monitoring helper functions for governors use */
 434
 435 /**
 436  * update_devfreq() - Reevaluate the device and configure frequency.
 437  * @devfreq:    the devfreq instance.
 438  *
 439  * Note: Lock devfreq->lock before calling update_devfreq
 440  *       This function is exported for governors.
 441  */
 442 int update_devfreq(struct devfreq *devfreq)
 443 {
 444         return devfreq_update_target(devfreq, 0L);
 445 }
 446 EXPORT_SYMBOL(update_devfreq);
 447
 448 /**
 449  * devfreq_monitor() - Periodically poll devfreq objects.
 450  * @work:       the work struct used to run devfreq_monitor periodically.
 451  *
 452  */
 453 static void devfreq_monitor(struct work_struct *work)
 454 {
 455         int err;
 456         struct devfreq *devfreq = container_of(work,
 457                                         struct devfreq, work.work);
 458
 459         mutex_lock(&devfreq->lock);
 460         err = update_devfreq(devfreq);
 461         if (err)
 462                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 463
 464         if (devfreq->stop_polling)
 465                 goto out;
 466
 467         queue_delayed_work(devfreq_wq, &devfreq->work,
 468                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 469
 470 out:
 471         mutex_unlock(&devfreq->lock);
 472         trace_devfreq_monitor(devfreq);
 473 }
 474
 475 /**
 476  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 477  * @devfreq:    the devfreq instance.
 478  *
 479  * Helper function for starting devfreq device load monitoring. By default,
 480  * deferrable timer is used for load monitoring. But the users can change this
 481  * behavior using the "timer" type in devfreq_dev_profile. This function will be
 482  * called by devfreq governor in response to the DEVFREQ_GOV_START event
 483  * generated while adding a device to the devfreq framework.
 484  */
 485 void devfreq_monitor_start(struct devfreq *devfreq)
 486 {
 487         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 488                 return;
 489
 490         mutex_lock(&devfreq->lock);
 491         if (delayed_work_pending(&devfreq->work))
 492                 goto out;
 493
 494         switch (devfreq->profile->timer) {
 495         case DEVFREQ_TIMER_DEFERRABLE:
 496                 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 497                 break;
 498         case DEVFREQ_TIMER_DELAYED:
 499                 INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
 500                 break;
 501         default:
 502                 goto out;
 503         }
 504
 505         if (devfreq->profile->polling_ms)
 506                 queue_delayed_work(devfreq_wq, &devfreq->work,
 507                         msecs_to_jiffies(devfreq->profile->polling_ms));
 508
 509 out:
 510         devfreq->stop_polling = false;
 511         mutex_unlock(&devfreq->lock);
 512 }
 513 EXPORT_SYMBOL(devfreq_monitor_start);
 514
 515 /**
 516  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 517  * @devfreq:    the devfreq instance.
 518  *
 519  * Helper function to stop devfreq device load monitoring. Function
 520  * to be called from governor in response to DEVFREQ_GOV_STOP
 521  * event when device is removed from devfreq framework.
 522  */
 523 void devfreq_monitor_stop(struct devfreq *devfreq)
 524 {
 525         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 526                 return;
 527
 528         mutex_lock(&devfreq->lock);
 529         if (devfreq->stop_polling) {
 530                 mutex_unlock(&devfreq->lock);
 531                 return;
 532         }
 533
 534         devfreq->stop_polling = true;
 535         mutex_unlock(&devfreq->lock);
 536         cancel_delayed_work_sync(&devfreq->work);
 537 }
 538 EXPORT_SYMBOL(devfreq_monitor_stop);
 539
 540 /**
 541  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 542  * @devfreq:    the devfreq instance.
 543  *
 544  * Helper function to suspend devfreq device load monitoring. Function
 545  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 546  * event or when polling interval is set to zero.
 547  *
 548  * Note: Though this function is same as devfreq_monitor_stop(),
 549  * intentionally kept separate to provide hooks for collecting
 550  * transition statistics.
 551  */
 552 void devfreq_monitor_suspend(struct devfreq *devfreq)
 553 {
 554         mutex_lock(&devfreq->lock);
 555         if (devfreq->stop_polling) {
 556                 mutex_unlock(&devfreq->lock);
 557                 return;
 558         }
 559
 560         devfreq_update_status(devfreq, devfreq->previous_freq);
 561         devfreq->stop_polling = true;
 562         mutex_unlock(&devfreq->lock);
 563
 564         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 565                 return;
 566
 567         cancel_delayed_work_sync(&devfreq->work);
 568 }
 569 EXPORT_SYMBOL(devfreq_monitor_suspend);
 570
 571 /**
 572  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 573  * @devfreq:    the devfreq instance.
 574  *
 575  * Helper function to resume devfreq device load monitoring. Function
 576  * to be called from governor in response to DEVFREQ_GOV_RESUME
 577  * event or when polling interval is set to non-zero.
 578  */
 579 void devfreq_monitor_resume(struct devfreq *devfreq)
 580 {
 581         unsigned long freq;
 582
 583         mutex_lock(&devfreq->lock);
 584
 585         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 586                 goto out_update;
 587
 588         if (!devfreq->stop_polling)
 589                 goto out;
 590
 591         if (!delayed_work_pending(&devfreq->work) &&
 592                         devfreq->profile->polling_ms)
 593                 queue_delayed_work(devfreq_wq, &devfreq->work,
 594                         msecs_to_jiffies(devfreq->profile->polling_ms));
 595
 596 out_update:
 597         devfreq->stats.last_update = get_jiffies_64();
 598         devfreq->stop_polling = false;
 599
 600         if (devfreq->profile->get_cur_freq &&
 601                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 602                 devfreq->previous_freq = freq;
 603
 604 out:
 605         mutex_unlock(&devfreq->lock);
 606 }
 607 EXPORT_SYMBOL(devfreq_monitor_resume);
 608
 609 /**
 610  * devfreq_update_interval() - Update device devfreq monitoring interval
 611  * @devfreq:    the devfreq instance.
 612  * @delay:      new polling interval to be set.
 613  *
 614  * Helper function to set new load monitoring polling interval. Function
 615  * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 616  */
 617 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 618 {
 619         unsigned int cur_delay = devfreq->profile->polling_ms;
 620         unsigned int new_delay = *delay;
 621
 622         mutex_lock(&devfreq->lock);
 623         devfreq->profile->polling_ms = new_delay;
 624
 625         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 626                 goto out;
 627
 628         if (devfreq->stop_polling)
 629                 goto out;
 630
 631         /* if new delay is zero, stop polling */
 632         if (!new_delay) {
 633                 mutex_unlock(&devfreq->lock);
 634                 cancel_delayed_work_sync(&devfreq->work);
 635                 return;
 636         }
 637
 638         /* if current delay is zero, start polling with new delay */
 639         if (!cur_delay) {
 640                 queue_delayed_work(devfreq_wq, &devfreq->work,
 641                         msecs_to_jiffies(devfreq->profile->polling_ms));
 642                 goto out;
 643         }
 644
 645         /* if current delay is greater than new delay, restart polling */
 646         if (cur_delay > new_delay) {
 647                 mutex_unlock(&devfreq->lock);
 648                 cancel_delayed_work_sync(&devfreq->work);
 649                 mutex_lock(&devfreq->lock);
 650                 if (!devfreq->stop_polling)
 651                         queue_delayed_work(devfreq_wq, &devfreq->work,
 652                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 653         }
 654 out:
 655         mutex_unlock(&devfreq->lock);
 656 }
 657 EXPORT_SYMBOL(devfreq_update_interval);
 658
 659 /**
 660  * devfreq_notifier_call() - Notify that the device frequency requirements
 661  *                           has been changed out of devfreq framework.
 662  * @nb:         the notifier_block (supposed to be devfreq->nb)
 663  * @type:       not used
 664  * @devp:       not used
 665  *
 666  * Called by a notifier that uses devfreq->nb.
 667  */
 668 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 669                                  void *devp)
 670 {
 671         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 672         int err = -EINVAL;
 673
 674         mutex_lock(&devfreq->lock);
 675
 676         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 677         if (!devfreq->scaling_min_freq)
 678                 goto out;
 679
 680         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 681         if (!devfreq->scaling_max_freq) {
 682                 devfreq->scaling_max_freq = ULONG_MAX;
 683                 goto out;
 684         }
 685
 686         err = update_devfreq(devfreq);
 687
 688 out:
 689         mutex_unlock(&devfreq->lock);
 690         if (err)
 691                 dev_err(devfreq->dev.parent,
 692                         "failed to update frequency from OPP notifier (%d)\n",
 693                         err);
 694
 695         return NOTIFY_OK;
 696 }
 697
 698 /**
 699  * qos_notifier_call() - Common handler for QoS constraints.
 700  * @devfreq:    the devfreq instance.
 701  */
 702 static int qos_notifier_call(struct devfreq *devfreq)
 703 {
 704         int err;
 705
 706         mutex_lock(&devfreq->lock);
 707         err = update_devfreq(devfreq);
 708         mutex_unlock(&devfreq->lock);
 709         if (err)
 710                 dev_err(devfreq->dev.parent,
 711                         "failed to update frequency from PM QoS (%d)\n",
 712                         err);
 713
 714         return NOTIFY_OK;
 715 }
 716
 717 /**
 718  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 719  * @nb:         Should be devfreq->nb_min
 720  * @val:        not used
 721  * @ptr:        not used
 722  */
 723 static int qos_min_notifier_call(struct notifier_block *nb,
 724                                          unsigned long val, void *ptr)
 725 {
 726         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 727 }
 728
 729 /**
 730  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 731  * @nb:         Should be devfreq->nb_max
 732  * @val:        not used
 733  * @ptr:        not used
 734  */
 735 static int qos_max_notifier_call(struct notifier_block *nb,
 736                                          unsigned long val, void *ptr)
 737 {
 738         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 739 }
 740
 741 /**
 742  * devfreq_dev_release() - Callback for struct device to release the device.
 743  * @dev:        the devfreq device
 744  *
 745  * Remove devfreq from the list and release its resources.
 746  */
 747 static void devfreq_dev_release(struct device *dev)
 748 {
 749         struct devfreq *devfreq = to_devfreq(dev);
 750         int err;
 751
 752         mutex_lock(&devfreq_list_lock);
 753         list_del(&devfreq->node);
 754         mutex_unlock(&devfreq_list_lock);
 755
 756         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 757                                          DEV_PM_QOS_MAX_FREQUENCY);
 758         if (err && err != -ENOENT)
 759                 dev_warn(dev->parent,
 760                         "Failed to remove max_freq notifier: %d\n", err);
 761         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 762                                          DEV_PM_QOS_MIN_FREQUENCY);
 763         if (err && err != -ENOENT)
 764                 dev_warn(dev->parent,
 765                         "Failed to remove min_freq notifier: %d\n", err);
 766
 767         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 768                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 769                 if (err < 0)
 770                         dev_warn(dev->parent,
 771                                 "Failed to remove max_freq request: %d\n", err);
 772         }
 773         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 774                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 775                 if (err < 0)
 776                         dev_warn(dev->parent,
 777                                 "Failed to remove min_freq request: %d\n", err);
 778         }
 779
 780         if (devfreq->profile->exit)
 781                 devfreq->profile->exit(devfreq->dev.parent);
 782
 783         if (devfreq->opp_table)
 784                 dev_pm_opp_put_opp_table(devfreq->opp_table);
 785
 786         mutex_destroy(&devfreq->lock);
 787         srcu_cleanup_notifier_head(&devfreq->transition_notifier_list);
 788         kfree(devfreq);
 789 }
 790
 791 static void create_sysfs_files(struct devfreq *devfreq,
 792                                 const struct devfreq_governor *gov);
 793 static void remove_sysfs_files(struct devfreq *devfreq,
 794                                 const struct devfreq_governor *gov);
 795
 796 /**
 797  * devfreq_add_device() - Add devfreq feature to the device
 798  * @dev:        the device to add devfreq feature.
 799  * @profile:    device-specific profile to run devfreq.
 800  * @governor_name:      name of the policy to choose frequency.
 801  * @data:       devfreq driver pass to governors, governor should not change it.
 802  */
 803 struct devfreq *devfreq_add_device(struct device *dev,
 804                                    struct devfreq_dev_profile *profile,
 805                                    const char *governor_name,
 806                                    void *data)
 807 {
 808         struct devfreq *devfreq;
 809         struct devfreq_governor *governor;
 810         unsigned long min_freq, max_freq;
 811         int err = 0;
 812
 813         if (!dev || !profile || !governor_name) {
 814                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 815                 return ERR_PTR(-EINVAL);
 816         }
 817
 818         mutex_lock(&devfreq_list_lock);
 819         devfreq = find_device_devfreq(dev);
 820         mutex_unlock(&devfreq_list_lock);
 821         if (!IS_ERR(devfreq)) {
 822                 dev_err(dev, "%s: devfreq device already exists!\n",
 823                         __func__);
 824                 err = -EINVAL;
 825                 goto err_out;
 826         }
 827
 828         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 829         if (!devfreq) {
 830                 err = -ENOMEM;
 831                 goto err_out;
 832         }
 833
 834         mutex_init(&devfreq->lock);
 835         mutex_lock(&devfreq->lock);
 836         devfreq->dev.parent = dev;
 837         devfreq->dev.class = devfreq_class;
 838         devfreq->dev.release = devfreq_dev_release;
 839         INIT_LIST_HEAD(&devfreq->node);
 840         devfreq->profile = profile;
 841         devfreq->previous_freq = profile->initial_freq;
 842         devfreq->last_status.current_frequency = profile->initial_freq;
 843         devfreq->data = data;
 844         devfreq->nb.notifier_call = devfreq_notifier_call;
 845
 846         if (devfreq->profile->timer < 0
 847                 || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 848                 mutex_unlock(&devfreq->lock);
 849                 err = -EINVAL;
 850                 goto err_dev;
 851         }
 852
 853         if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
 854                 mutex_unlock(&devfreq->lock);
 855                 err = set_freq_table(devfreq);
 856                 if (err < 0)
 857                         goto err_dev;
 858                 mutex_lock(&devfreq->lock);
 859         } else {
 860                 devfreq->freq_table = devfreq->profile->freq_table;
 861                 devfreq->max_state = devfreq->profile->max_state;
 862         }
 863
 864         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 865         if (!devfreq->scaling_min_freq) {
 866                 mutex_unlock(&devfreq->lock);
 867                 err = -EINVAL;
 868                 goto err_dev;
 869         }
 870
 871         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 872         if (!devfreq->scaling_max_freq) {
 873                 mutex_unlock(&devfreq->lock);
 874                 err = -EINVAL;
 875                 goto err_dev;
 876         }
 877
 878         devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 879
 880         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 881         devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
 882         if (IS_ERR(devfreq->opp_table))
 883                 devfreq->opp_table = NULL;
 884
 885         atomic_set(&devfreq->suspend_count, 0);
 886
 887         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 888         err = device_register(&devfreq->dev);
 889         if (err) {
 890                 mutex_unlock(&devfreq->lock);
 891                 put_device(&devfreq->dev);
 892                 goto err_out;
 893         }
 894
 895         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 896                         array3_size(sizeof(unsigned int),
 897                                     devfreq->max_state,
 898                                     devfreq->max_state),
 899                         GFP_KERNEL);
 900         if (!devfreq->stats.trans_table) {
 901                 mutex_unlock(&devfreq->lock);
 902                 err = -ENOMEM;
 903                 goto err_devfreq;
 904         }
 905
 906         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 907                         devfreq->max_state,
 908                         sizeof(*devfreq->stats.time_in_state),
 909                         GFP_KERNEL);
 910         if (!devfreq->stats.time_in_state) {
 911                 mutex_unlock(&devfreq->lock);
 912                 err = -ENOMEM;
 913                 goto err_devfreq;
 914         }
 915
 916         devfreq->stats.total_trans = 0;
 917         devfreq->stats.last_update = get_jiffies_64();
 918
 919         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 920
 921         mutex_unlock(&devfreq->lock);
 922
 923         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 924                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 925         if (err < 0)
 926                 goto err_devfreq;
 927         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 928                                      DEV_PM_QOS_MAX_FREQUENCY,
 929                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 930         if (err < 0)
 931                 goto err_devfreq;
 932
 933         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 934         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
 935                                       DEV_PM_QOS_MIN_FREQUENCY);
 936         if (err)
 937                 goto err_devfreq;
 938
 939         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 940         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
 941                                       DEV_PM_QOS_MAX_FREQUENCY);
 942         if (err)
 943                 goto err_devfreq;
 944
 945         mutex_lock(&devfreq_list_lock);
 946
 947         governor = try_then_request_governor(governor_name);
 948         if (IS_ERR(governor)) {
 949                 dev_err(dev, "%s: Unable to find governor for the device\n",
 950                         __func__);
 951                 err = PTR_ERR(governor);
 952                 goto err_init;
 953         }
 954
 955         devfreq->governor = governor;
 956         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 957                                                 NULL);
 958         if (err) {
 959                 dev_err_probe(dev, err,
 960                         "%s: Unable to start governor for the device\n",
 961                          __func__);
 962                 goto err_init;
 963         }
 964         create_sysfs_files(devfreq, devfreq->governor);
 965
 966         list_add(&devfreq->node, &devfreq_list);
 967
 968         mutex_unlock(&devfreq_list_lock);
 969
 970         if (devfreq->profile->is_cooling_device) {
 971                 devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
 972                 if (IS_ERR(devfreq->cdev))
 973                         devfreq->cdev = NULL;
 974         }
 975
 976         return devfreq;
 977
 978 err_init:
 979         mutex_unlock(&devfreq_list_lock);
 980 err_devfreq:
 981         devfreq_remove_device(devfreq);
 982         devfreq = NULL;
 983 err_dev:
 984         kfree(devfreq);
 985 err_out:
 986         return ERR_PTR(err);
 987 }
 988 EXPORT_SYMBOL(devfreq_add_device);
 989
 990 /**
 991  * devfreq_remove_device() - Remove devfreq feature from a device.
 992  * @devfreq:    the devfreq instance to be removed
 993  *
 994  * The opposite of devfreq_add_device().
 995  */
 996 int devfreq_remove_device(struct devfreq *devfreq)
 997 {
 998         if (!devfreq)
 999                 return -EINVAL;
1000
1001         devfreq_cooling_unregister(devfreq->cdev);
1002
1003         if (devfreq->governor) {
1004                 devfreq->governor->event_handler(devfreq,
1005                                                  DEVFREQ_GOV_STOP, NULL);
1006                 remove_sysfs_files(devfreq, devfreq->governor);
1007         }
1008
1009         device_unregister(&devfreq->dev);
1010
1011         return 0;
1012 }
1013 EXPORT_SYMBOL(devfreq_remove_device);
1014
1015 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
1016 {
1017         struct devfreq **r = res;
1018
1019         if (WARN_ON(!r || !*r))
1020                 return 0;
1021
1022         return *r == data;
1023 }
1024
1025 static void devm_devfreq_dev_release(struct device *dev, void *res)
1026 {
1027         devfreq_remove_device(*(struct devfreq **)res);
1028 }
1029
1030 /**
1031  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
1032  * @dev:        the device to add devfreq feature.
1033  * @profile:    device-specific profile to run devfreq.
1034  * @governor_name:      name of the policy to choose frequency.
1035  * @data:        devfreq driver pass to governors, governor should not change it.
1036  *
1037  * This function manages automatically the memory of devfreq device using device
1038  * resource management and simplify the free operation for memory of devfreq
1039  * device.
1040  */
1041 struct devfreq *devm_devfreq_add_device(struct device *dev,
1042                                         struct devfreq_dev_profile *profile,
1043                                         const char *governor_name,
1044                                         void *data)
1045 {
1046         struct devfreq **ptr, *devfreq;
1047
1048         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
1049         if (!ptr)
1050                 return ERR_PTR(-ENOMEM);
1051
1052         devfreq = devfreq_add_device(dev, profile, governor_name, data);
1053         if (IS_ERR(devfreq)) {
1054                 devres_free(ptr);
1055                 return devfreq;
1056         }
1057
1058         *ptr = devfreq;
1059         devres_add(dev, ptr);
1060
1061         return devfreq;
1062 }
1063 EXPORT_SYMBOL(devm_devfreq_add_device);
1064
1065 #ifdef CONFIG_OF
1066 /*
1067  * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1068  * @node - pointer to device_node
1069  *
1070  * return the instance of devfreq device
1071  */
1072 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1073 {
1074         struct devfreq *devfreq;
1075
1076         if (!node)
1077                 return ERR_PTR(-EINVAL);
1078
1079         mutex_lock(&devfreq_list_lock);
1080         list_for_each_entry(devfreq, &devfreq_list, node) {
1081                 if (devfreq->dev.parent
1082                         && device_match_of_node(devfreq->dev.parent, node)) {
1083                         mutex_unlock(&devfreq_list_lock);
1084                         return devfreq;
1085                 }
1086         }
1087         mutex_unlock(&devfreq_list_lock);
1088
1089         return ERR_PTR(-ENODEV);
1090 }
1091
1092 /*
1093  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1094  * @dev - instance to the given device
1095  * @phandle_name - name of property holding a phandle value
1096  * @index - index into list of devfreq
1097  *
1098  * return the instance of devfreq device
1099  */
1100 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1101                                         const char *phandle_name, int index)
1102 {
1103         struct device_node *node;
1104         struct devfreq *devfreq;
1105
1106         if (!dev || !phandle_name)
1107                 return ERR_PTR(-EINVAL);
1108
1109         if (!dev->of_node)
1110                 return ERR_PTR(-EINVAL);
1111
1112         node = of_parse_phandle(dev->of_node, phandle_name, index);
1113         if (!node)
1114                 return ERR_PTR(-ENODEV);
1115
1116         devfreq = devfreq_get_devfreq_by_node(node);
1117         of_node_put(node);
1118
1119         return devfreq;
1120 }
1121
1122 #else
1123 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1124 {
1125         return ERR_PTR(-ENODEV);
1126 }
1127
1128 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1129                                         const char *phandle_name, int index)
1130 {
1131         return ERR_PTR(-ENODEV);
1132 }
1133 #endif /* CONFIG_OF */
1134 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1135 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1136
1137 /**
1138  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1139  * @dev:        the device from which to remove devfreq feature.
1140  * @devfreq:    the devfreq instance to be removed
1141  */
1142 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1143 {
1144         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1145                                devm_devfreq_dev_match, devfreq));
1146 }
1147 EXPORT_SYMBOL(devm_devfreq_remove_device);
1148
1149 /**
1150  * devfreq_suspend_device() - Suspend devfreq of a device.
1151  * @devfreq: the devfreq instance to be suspended
1152  *
1153  * This function is intended to be called by the pm callbacks
1154  * (e.g., runtime_suspend, suspend) of the device driver that
1155  * holds the devfreq.
1156  */
1157 int devfreq_suspend_device(struct devfreq *devfreq)
1158 {
1159         int ret;
1160
1161         if (!devfreq)
1162                 return -EINVAL;
1163
1164         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1165                 return 0;
1166
1167         if (devfreq->governor) {
1168                 ret = devfreq->governor->event_handler(devfreq,
1169                                         DEVFREQ_GOV_SUSPEND, NULL);
1170                 if (ret)
1171                         return ret;
1172         }
1173
1174         if (devfreq->suspend_freq) {
1175                 mutex_lock(&devfreq->lock);
1176                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1177                 mutex_unlock(&devfreq->lock);
1178                 if (ret)
1179                         return ret;
1180         }
1181
1182         return 0;
1183 }
1184 EXPORT_SYMBOL(devfreq_suspend_device);
1185
1186 /**
1187  * devfreq_resume_device() - Resume devfreq of a device.
1188  * @devfreq: the devfreq instance to be resumed
1189  *
1190  * This function is intended to be called by the pm callbacks
1191  * (e.g., runtime_resume, resume) of the device driver that
1192  * holds the devfreq.
1193  */
1194 int devfreq_resume_device(struct devfreq *devfreq)
1195 {
1196         int ret;
1197
1198         if (!devfreq)
1199                 return -EINVAL;
1200
1201         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1202                 return 0;
1203
1204         if (devfreq->resume_freq) {
1205                 mutex_lock(&devfreq->lock);
1206                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1207                 mutex_unlock(&devfreq->lock);
1208                 if (ret)
1209                         return ret;
1210         }
1211
1212         if (devfreq->governor) {
1213                 ret = devfreq->governor->event_handler(devfreq,
1214                                         DEVFREQ_GOV_RESUME, NULL);
1215                 if (ret)
1216                         return ret;
1217         }
1218
1219         return 0;
1220 }
1221 EXPORT_SYMBOL(devfreq_resume_device);
1222
1223 /**
1224  * devfreq_suspend() - Suspend devfreq governors and devices
1225  *
1226  * Called during system wide Suspend/Hibernate cycles for suspending governors
1227  * and devices preserving the state for resume. On some platforms the devfreq
1228  * device must have precise state (frequency) after resume in order to provide
1229  * fully operating setup.
1230  */
1231 void devfreq_suspend(void)
1232 {
1233         struct devfreq *devfreq;
1234         int ret;
1235
1236         mutex_lock(&devfreq_list_lock);
1237         list_for_each_entry(devfreq, &devfreq_list, node) {
1238                 ret = devfreq_suspend_device(devfreq);
1239                 if (ret)
1240                         dev_err(&devfreq->dev,
1241                                 "failed to suspend devfreq device\n");
1242         }
1243         mutex_unlock(&devfreq_list_lock);
1244 }
1245
1246 /**
1247  * devfreq_resume() - Resume devfreq governors and devices
1248  *
1249  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1250  * devices that are suspended with devfreq_suspend().
1251  */
1252 void devfreq_resume(void)
1253 {
1254         struct devfreq *devfreq;
1255         int ret;
1256
1257         mutex_lock(&devfreq_list_lock);
1258         list_for_each_entry(devfreq, &devfreq_list, node) {
1259                 ret = devfreq_resume_device(devfreq);
1260                 if (ret)
1261                         dev_warn(&devfreq->dev,
1262                                  "failed to resume devfreq device\n");
1263         }
1264         mutex_unlock(&devfreq_list_lock);
1265 }
1266
1267 /**
1268  * devfreq_add_governor() - Add devfreq governor
1269  * @governor:   the devfreq governor to be added
1270  */
1271 int devfreq_add_governor(struct devfreq_governor *governor)
1272 {
1273         struct devfreq_governor *g;
1274         struct devfreq *devfreq;
1275         int err = 0;
1276
1277         if (!governor) {
1278                 pr_err("%s: Invalid parameters.\n", __func__);
1279                 return -EINVAL;
1280         }
1281
1282         mutex_lock(&devfreq_list_lock);
1283         g = find_devfreq_governor(governor->name);
1284         if (!IS_ERR(g)) {
1285                 pr_err("%s: governor %s already registered\n", __func__,
1286                        g->name);
1287                 err = -EINVAL;
1288                 goto err_out;
1289         }
1290
1291         list_add(&governor->node, &devfreq_governor_list);
1292
1293         list_for_each_entry(devfreq, &devfreq_list, node) {
1294                 int ret = 0;
1295                 struct device *dev = devfreq->dev.parent;
1296
1297                 if (!strncmp(devfreq->governor->name, governor->name,
1298                              DEVFREQ_NAME_LEN)) {
1299                         /* The following should never occur */
1300                         if (devfreq->governor) {
1301                                 dev_warn(dev,
1302                                          "%s: Governor %s already present\n",
1303                                          __func__, devfreq->governor->name);
1304                                 ret = devfreq->governor->event_handler(devfreq,
1305                                                         DEVFREQ_GOV_STOP, NULL);
1306                                 if (ret) {
1307                                         dev_warn(dev,
1308                                                  "%s: Governor %s stop = %d\n",
1309                                                  __func__,
1310                                                  devfreq->governor->name, ret);
1311                                 }
1312                                 /* Fall through */
1313                         }
1314                         devfreq->governor = governor;
1315                         ret = devfreq->governor->event_handler(devfreq,
1316                                                 DEVFREQ_GOV_START, NULL);
1317                         if (ret) {
1318                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1319                                          __func__, devfreq->governor->name,
1320                                          ret);
1321                         }
1322                 }
1323         }
1324
1325 err_out:
1326         mutex_unlock(&devfreq_list_lock);
1327
1328         return err;
1329 }
1330 EXPORT_SYMBOL(devfreq_add_governor);
1331
1332 static void devm_devfreq_remove_governor(void *governor)
1333 {
1334         WARN_ON(devfreq_remove_governor(governor));
1335 }
1336
1337 /**
1338  * devm_devfreq_add_governor() - Add devfreq governor
1339  * @dev:        device which adds devfreq governor
1340  * @governor:   the devfreq governor to be added
1341  *
1342  * This is a resource-managed variant of devfreq_add_governor().
1343  */
1344 int devm_devfreq_add_governor(struct device *dev,
1345                               struct devfreq_governor *governor)
1346 {
1347         int err;
1348
1349         err = devfreq_add_governor(governor);
1350         if (err)
1351                 return err;
1352
1353         return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
1354                                         governor);
1355 }
1356 EXPORT_SYMBOL(devm_devfreq_add_governor);
1357
1358 /**
1359  * devfreq_remove_governor() - Remove devfreq feature from a device.
1360  * @governor:   the devfreq governor to be removed
1361  */
1362 int devfreq_remove_governor(struct devfreq_governor *governor)
1363 {
1364         struct devfreq_governor *g;
1365         struct devfreq *devfreq;
1366         int err = 0;
1367
1368         if (!governor) {
1369                 pr_err("%s: Invalid parameters.\n", __func__);
1370                 return -EINVAL;
1371         }
1372
1373         mutex_lock(&devfreq_list_lock);
1374         g = find_devfreq_governor(governor->name);
1375         if (IS_ERR(g)) {
1376                 pr_err("%s: governor %s not registered\n", __func__,
1377                        governor->name);
1378                 err = PTR_ERR(g);
1379                 goto err_out;
1380         }
1381         list_for_each_entry(devfreq, &devfreq_list, node) {
1382                 int ret;
1383                 struct device *dev = devfreq->dev.parent;
1384
1385                 if (!strncmp(devfreq->governor->name, governor->name,
1386                              DEVFREQ_NAME_LEN)) {
1387                         /* we should have a devfreq governor! */
1388                         if (!devfreq->governor) {
1389                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1390                                          __func__, governor->name);
1391                                 continue;
1392                                 /* Fall through */
1393                         }
1394                         ret = devfreq->governor->event_handler(devfreq,
1395                                                 DEVFREQ_GOV_STOP, NULL);
1396                         if (ret) {
1397                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1398                                          __func__, devfreq->governor->name,
1399                                          ret);
1400                         }
1401                         devfreq->governor = NULL;
1402                 }
1403         }
1404
1405         list_del(&governor->node);
1406 err_out:
1407         mutex_unlock(&devfreq_list_lock);
1408
1409         return err;
1410 }
1411 EXPORT_SYMBOL(devfreq_remove_governor);
1412
1413 static ssize_t name_show(struct device *dev,
1414                         struct device_attribute *attr, char *buf)
1415 {
1416         struct devfreq *df = to_devfreq(dev);
1417         return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1418 }
1419 static DEVICE_ATTR_RO(name);
1420
1421 static ssize_t governor_show(struct device *dev,
1422                              struct device_attribute *attr, char *buf)
1423 {
1424         struct devfreq *df = to_devfreq(dev);
1425
1426         if (!df->governor)
1427                 return -EINVAL;
1428
1429         return sprintf(buf, "%s\n", df->governor->name);
1430 }
1431
1432 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1433                               const char *buf, size_t count)
1434 {
1435         struct devfreq *df = to_devfreq(dev);
1436         int ret;
1437         char str_governor[DEVFREQ_NAME_LEN + 1];
1438         const struct devfreq_governor *governor, *prev_governor;
1439
1440         if (!df->governor)
1441                 return -EINVAL;
1442
1443         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1444         if (ret != 1)
1445                 return -EINVAL;
1446
1447         mutex_lock(&devfreq_list_lock);
1448         governor = try_then_request_governor(str_governor);
1449         if (IS_ERR(governor)) {
1450                 ret = PTR_ERR(governor);
1451                 goto out;
1452         }
1453         if (df->governor == governor) {
1454                 ret = 0;
1455                 goto out;
1456         } else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
1457                 || IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
1458                 ret = -EINVAL;
1459                 goto out;
1460         }
1461
1462         /*
1463          * Stop the current governor and remove the specific sysfs files
1464          * which depend on current governor.
1465          */
1466         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1467         if (ret) {
1468                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1469                          __func__, df->governor->name, ret);
1470                 goto out;
1471         }
1472         remove_sysfs_files(df, df->governor);
1473
1474         /*
1475          * Start the new governor and create the specific sysfs files
1476          * which depend on the new governor.
1477          */
1478         prev_governor = df->governor;
1479         df->governor = governor;
1480         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1481         if (ret) {
1482                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1483                          __func__, df->governor->name, ret);
1484
1485                 /* Restore previous governor */
1486                 df->governor = prev_governor;
1487                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1488                 if (ret) {
1489                         dev_err(dev,
1490                                 "%s: reverting to Governor %s failed (%d)\n",
1491                                 __func__, prev_governor->name, ret);
1492                         df->governor = NULL;
1493                         goto out;
1494                 }
1495         }
1496
1497         /*
1498          * Create the sysfs files for the new governor. But if failed to start
1499          * the new governor, restore the sysfs files of previous governor.
1500          */
1501         create_sysfs_files(df, df->governor);
1502
1503 out:
1504         mutex_unlock(&devfreq_list_lock);
1505
1506         if (!ret)
1507                 ret = count;
1508         return ret;
1509 }
1510 static DEVICE_ATTR_RW(governor);
1511
1512 static ssize_t available_governors_show(struct device *d,
1513                                         struct device_attribute *attr,
1514                                         char *buf)
1515 {
1516         struct devfreq *df = to_devfreq(d);
1517         ssize_t count = 0;
1518
1519         if (!df->governor)
1520                 return -EINVAL;
1521
1522         mutex_lock(&devfreq_list_lock);
1523
1524         /*
1525          * The devfreq with immutable governor (e.g., passive) shows
1526          * only own governor.
1527          */
1528         if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
1529                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1530                                   "%s ", df->governor->name);
1531         /*
1532          * The devfreq device shows the registered governor except for
1533          * immutable governors such as passive governor .
1534          */
1535         } else {
1536                 struct devfreq_governor *governor;
1537
1538                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1539                         if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
1540                                 continue;
1541                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1542                                            "%s ", governor->name);
1543                 }
1544         }
1545
1546         mutex_unlock(&devfreq_list_lock);
1547
1548         /* Truncate the trailing space */
1549         if (count)
1550                 count--;
1551
1552         count += sprintf(&buf[count], "\n");
1553
1554         return count;
1555 }
1556 static DEVICE_ATTR_RO(available_governors);
1557
1558 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1559                              char *buf)
1560 {
1561         unsigned long freq;
1562         struct devfreq *df = to_devfreq(dev);
1563
1564         if (!df->profile)
1565                 return -EINVAL;
1566
1567         if (df->profile->get_cur_freq &&
1568                 !df->profile->get_cur_freq(df->dev.parent, &freq))
1569                 return sprintf(buf, "%lu\n", freq);
1570
1571         return sprintf(buf, "%lu\n", df->previous_freq);
1572 }
1573 static DEVICE_ATTR_RO(cur_freq);
1574
1575 static ssize_t target_freq_show(struct device *dev,
1576                                 struct device_attribute *attr, char *buf)
1577 {
1578         struct devfreq *df = to_devfreq(dev);
1579
1580         return sprintf(buf, "%lu\n", df->previous_freq);
1581 }
1582 static DEVICE_ATTR_RO(target_freq);
1583
1584 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1585                               const char *buf, size_t count)
1586 {
1587         struct devfreq *df = to_devfreq(dev);
1588         unsigned long value;
1589         int ret;
1590
1591         /*
1592          * Protect against theoretical sysfs writes between
1593          * device_add and dev_pm_qos_add_request
1594          */
1595         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1596                 return -EAGAIN;
1597
1598         ret = sscanf(buf, "%lu", &value);
1599         if (ret != 1)
1600                 return -EINVAL;
1601
1602         /* Round down to kHz for PM QoS */
1603         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1604                                         value / HZ_PER_KHZ);
1605         if (ret < 0)
1606                 return ret;
1607
1608         return count;
1609 }
1610
1611 static ssize_t min_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         devfreq_get_freq_range(df, &min_freq, &max_freq);
1619         mutex_unlock(&df->lock);
1620
1621         return sprintf(buf, "%lu\n", min_freq);
1622 }
1623 static DEVICE_ATTR_RW(min_freq);
1624
1625 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1626                               const char *buf, size_t count)
1627 {
1628         struct devfreq *df = to_devfreq(dev);
1629         unsigned long value;
1630         int ret;
1631
1632         /*
1633          * Protect against theoretical sysfs writes between
1634          * device_add and dev_pm_qos_add_request
1635          */
1636         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1637                 return -EINVAL;
1638
1639         ret = sscanf(buf, "%lu", &value);
1640         if (ret != 1)
1641                 return -EINVAL;
1642
1643         /*
1644          * PM QoS frequencies are in kHz so we need to convert. Convert by
1645          * rounding upwards so that the acceptable interval never shrinks.
1646          *
1647          * For example if the user writes "666666666" to sysfs this value will
1648          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1649          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1650          *
1651          * A value of zero means "no limit".
1652          */
1653         if (value)
1654                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1655         else
1656                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1657
1658         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1659         if (ret < 0)
1660                 return ret;
1661
1662         return count;
1663 }
1664
1665 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1666                              char *buf)
1667 {
1668         struct devfreq *df = to_devfreq(dev);
1669         unsigned long min_freq, max_freq;
1670
1671         mutex_lock(&df->lock);
1672         devfreq_get_freq_range(df, &min_freq, &max_freq);
1673         mutex_unlock(&df->lock);
1674
1675         return sprintf(buf, "%lu\n", max_freq);
1676 }
1677 static DEVICE_ATTR_RW(max_freq);
1678
1679 static ssize_t available_frequencies_show(struct device *d,
1680                                           struct device_attribute *attr,
1681                                           char *buf)
1682 {
1683         struct devfreq *df = to_devfreq(d);
1684         ssize_t count = 0;
1685         int i;
1686
1687         if (!df->profile)
1688                 return -EINVAL;
1689
1690         mutex_lock(&df->lock);
1691
1692         for (i = 0; i < df->max_state; i++)
1693                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1694                                 "%lu ", df->freq_table[i]);
1695
1696         mutex_unlock(&df->lock);
1697         /* Truncate the trailing space */
1698         if (count)
1699                 count--;
1700
1701         count += sprintf(&buf[count], "\n");
1702
1703         return count;
1704 }
1705 static DEVICE_ATTR_RO(available_frequencies);
1706
1707 static ssize_t trans_stat_show(struct device *dev,
1708                                struct device_attribute *attr, char *buf)
1709 {
1710         struct devfreq *df = to_devfreq(dev);
1711         ssize_t len = 0;
1712         int i, j;
1713         unsigned int max_state;
1714
1715         if (!df->profile)
1716                 return -EINVAL;
1717         max_state = df->max_state;
1718
1719         if (max_state == 0)
1720                 return sysfs_emit(buf, "Not Supported.\n");
1721
1722         mutex_lock(&df->lock);
1723         if (!df->stop_polling &&
1724                         devfreq_update_status(df, df->previous_freq)) {
1725                 mutex_unlock(&df->lock);
1726                 return 0;
1727         }
1728         mutex_unlock(&df->lock);
1729
1730         len += sysfs_emit_at(buf, len, "     From  :   To\n");
1731         len += sysfs_emit_at(buf, len, "           :");
1732         for (i = 0; i < max_state; i++) {
1733                 if (len >= PAGE_SIZE - 1)
1734                         break;
1735                 len += sysfs_emit_at(buf, len, "%10lu",
1736                                      df->freq_table[i]);
1737         }
1738
1739         if (len >= PAGE_SIZE - 1)
1740                 return PAGE_SIZE - 1;
1741         len += sysfs_emit_at(buf, len, "   time(ms)\n");
1742
1743         for (i = 0; i < max_state; i++) {
1744                 if (len >= PAGE_SIZE - 1)
1745                         break;
1746                 if (df->freq_table[2] == df->previous_freq)
1747                         len += sysfs_emit_at(buf, len, "*");
1748                 else
1749                         len += sysfs_emit_at(buf, len, " ");
1750                 if (len >= PAGE_SIZE - 1)
1751                         break;
1752                 len += sysfs_emit_at(buf, len, "%10lu:", df->freq_table[i]);
1753                 for (j = 0; j < max_state; j++) {
1754                         if (len >= PAGE_SIZE - 1)
1755                                 break;
1756                         len += sysfs_emit_at(buf, len, "%10u",
1757                                 df->stats.trans_table[(i * max_state) + j]);
1758                 }
1759                 if (len >= PAGE_SIZE - 1)
1760                         break;
1761                 len += sysfs_emit_at(buf, len, "%10llu\n", (u64)
1762                                      jiffies64_to_msecs(df->stats.time_in_state[i]));
1763         }
1764
1765         if (len < PAGE_SIZE - 1)
1766                 len += sysfs_emit_at(buf, len, "Total transition : %u\n",
1767                                      df->stats.total_trans);
1768         if (len >= PAGE_SIZE - 1) {
1769                 pr_warn_once("devfreq transition table exceeds PAGE_SIZE. Disabling\n");
1770                 return -EFBIG;
1771         }
1772
1773         return len;
1774 }
1775
1776 static ssize_t trans_stat_store(struct device *dev,
1777                                 struct device_attribute *attr,
1778                                 const char *buf, size_t count)
1779 {
1780         struct devfreq *df = to_devfreq(dev);
1781         int err, value;
1782
1783         if (!df->profile)
1784                 return -EINVAL;
1785
1786         if (df->max_state == 0)
1787                 return count;
1788
1789         err = kstrtoint(buf, 10, &value);
1790         if (err || value != 0)
1791                 return -EINVAL;
1792
1793         mutex_lock(&df->lock);
1794         memset(df->stats.time_in_state, 0, (df->max_state *
1795                                         sizeof(*df->stats.time_in_state)));
1796         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1797                                         df->max_state,
1798                                         df->max_state));
1799         df->stats.total_trans = 0;
1800         df->stats.last_update = get_jiffies_64();
1801         mutex_unlock(&df->lock);
1802
1803         return count;
1804 }
1805 static DEVICE_ATTR_RW(trans_stat);
1806
1807 static struct attribute *devfreq_attrs[] = {
1808         &dev_attr_name.attr,
1809         &dev_attr_governor.attr,
1810         &dev_attr_available_governors.attr,
1811         &dev_attr_cur_freq.attr,
1812         &dev_attr_available_frequencies.attr,
1813         &dev_attr_target_freq.attr,
1814         &dev_attr_min_freq.attr,
1815         &dev_attr_max_freq.attr,
1816         &dev_attr_trans_stat.attr,
1817         NULL,
1818 };
1819 ATTRIBUTE_GROUPS(devfreq);
1820
1821 static ssize_t polling_interval_show(struct device *dev,
1822                                      struct device_attribute *attr, char *buf)
1823 {
1824         struct devfreq *df = to_devfreq(dev);
1825
1826         if (!df->profile)
1827                 return -EINVAL;
1828
1829         return sprintf(buf, "%d\n", df->profile->polling_ms);
1830 }
1831
1832 static ssize_t polling_interval_store(struct device *dev,
1833                                       struct device_attribute *attr,
1834                                       const char *buf, size_t count)
1835 {
1836         struct devfreq *df = to_devfreq(dev);
1837         unsigned int value;
1838         int ret;
1839
1840         if (!df->governor)
1841                 return -EINVAL;
1842
1843         ret = sscanf(buf, "%u", &value);
1844         if (ret != 1)
1845                 return -EINVAL;
1846
1847         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1848         ret = count;
1849
1850         return ret;
1851 }
1852 static DEVICE_ATTR_RW(polling_interval);
1853
1854 static ssize_t timer_show(struct device *dev,
1855                              struct device_attribute *attr, char *buf)
1856 {
1857         struct devfreq *df = to_devfreq(dev);
1858
1859         if (!df->profile)
1860                 return -EINVAL;
1861
1862         return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
1863 }
1864
1865 static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1866                               const char *buf, size_t count)
1867 {
1868         struct devfreq *df = to_devfreq(dev);
1869         char str_timer[DEVFREQ_NAME_LEN + 1];
1870         int timer = -1;
1871         int ret = 0, i;
1872
1873         if (!df->governor || !df->profile)
1874                 return -EINVAL;
1875
1876         ret = sscanf(buf, "%16s", str_timer);
1877         if (ret != 1)
1878                 return -EINVAL;
1879
1880         for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1881                 if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1882                         timer = i;
1883                         break;
1884                 }
1885         }
1886
1887         if (timer < 0) {
1888                 ret = -EINVAL;
1889                 goto out;
1890         }
1891
1892         if (df->profile->timer == timer) {
1893                 ret = 0;
1894                 goto out;
1895         }
1896
1897         mutex_lock(&df->lock);
1898         df->profile->timer = timer;
1899         mutex_unlock(&df->lock);
1900
1901         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1902         if (ret) {
1903                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1904                          __func__, df->governor->name, ret);
1905                 goto out;
1906         }
1907
1908         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1909         if (ret)
1910                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1911                          __func__, df->governor->name, ret);
1912 out:
1913         return ret ? ret : count;
1914 }
1915 static DEVICE_ATTR_RW(timer);
1916
1917 #define CREATE_SYSFS_FILE(df, name)                                     \
1918 {                                                                       \
1919         int ret;                                                        \
1920         ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);  \
1921         if (ret < 0) {                                                  \
1922                 dev_warn(&df->dev,                                      \
1923                         "Unable to create attr(%s)\n", "##name");       \
1924         }                                                               \
1925 }                                                                       \
1926
1927 /* Create the specific sysfs files which depend on each governor. */
1928 static void create_sysfs_files(struct devfreq *devfreq,
1929                                 const struct devfreq_governor *gov)
1930 {
1931         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1932                 CREATE_SYSFS_FILE(devfreq, polling_interval);
1933         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1934                 CREATE_SYSFS_FILE(devfreq, timer);
1935 }
1936
1937 /* Remove the specific sysfs files which depend on each governor. */
1938 static void remove_sysfs_files(struct devfreq *devfreq,
1939                                 const struct devfreq_governor *gov)
1940 {
1941         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1942                 sysfs_remove_file(&devfreq->dev.kobj,
1943                                 &dev_attr_polling_interval.attr);
1944         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1945                 sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
1946 }
1947
1948 /**
1949  * devfreq_summary_show() - Show the summary of the devfreq devices
1950  * @s:          seq_file instance to show the summary of devfreq devices
1951  * @data:       not used
1952  *
1953  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1954  * It helps that user can know the detailed information of the devfreq devices.
1955  *
1956  * Return 0 always because it shows the information without any data change.
1957  */
1958 static int devfreq_summary_show(struct seq_file *s, void *data)
1959 {
1960         struct devfreq *devfreq;
1961         struct devfreq *p_devfreq = NULL;
1962         unsigned long cur_freq, min_freq, max_freq;
1963         unsigned int polling_ms;
1964         unsigned int timer;
1965
1966         seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1967                         "dev",
1968                         "parent_dev",
1969                         "governor",
1970                         "timer",
1971                         "polling_ms",
1972                         "cur_freq_Hz",
1973                         "min_freq_Hz",
1974                         "max_freq_Hz");
1975         seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1976                         "------------------------------",
1977                         "------------------------------",
1978                         "---------------",
1979                         "----------",
1980                         "----------",
1981                         "------------",
1982                         "------------",
1983                         "------------");
1984
1985         mutex_lock(&devfreq_list_lock);
1986
1987         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1988 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1989                 if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
1990                                                         DEVFREQ_NAME_LEN)) {
1991                         struct devfreq_passive_data *data = devfreq->data;
1992
1993                         if (data)
1994                                 p_devfreq = data->parent;
1995                 } else {
1996                         p_devfreq = NULL;
1997                 }
1998 #endif
1999
2000                 mutex_lock(&devfreq->lock);
2001                 cur_freq = devfreq->previous_freq;
2002                 devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
2003                 timer = devfreq->profile->timer;
2004
2005                 if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
2006                         polling_ms = devfreq->profile->polling_ms;
2007                 else
2008                         polling_ms = 0;
2009                 mutex_unlock(&devfreq->lock);
2010
2011                 seq_printf(s,
2012                         "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
2013                         dev_name(&devfreq->dev),
2014                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
2015                         devfreq->governor->name,
2016                         polling_ms ? timer_name[timer] : "null",
2017                         polling_ms,
2018                         cur_freq,
2019                         min_freq,
2020                         max_freq);
2021         }
2022
2023         mutex_unlock(&devfreq_list_lock);
2024
2025         return 0;
2026 }
2027 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
2028
2029 static int __init devfreq_init(void)
2030 {
2031         devfreq_class = class_create("devfreq");
2032         if (IS_ERR(devfreq_class)) {
2033                 pr_err("%s: couldn't create class\n", __FILE__);
2034                 return PTR_ERR(devfreq_class);
2035         }
2036
2037         devfreq_wq = create_freezable_workqueue("devfreq_wq");
2038         if (!devfreq_wq) {
2039                 class_destroy(devfreq_class);
2040                 pr_err("%s: couldn't create workqueue\n", __FILE__);
2041                 return -ENOMEM;
2042         }
2043         devfreq_class->dev_groups = devfreq_groups;
2044
2045         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
2046         debugfs_create_file("devfreq_summary", 0444,
2047                                 devfreq_debugfs, NULL,
2048                                 &devfreq_summary_fops);
2049
2050         return 0;
2051 }
2052 subsys_initcall(devfreq_init);
2053
2054 /*
2055  * The following are helper functions for devfreq user device drivers with
2056  * OPP framework.
2057  */
2058
2059 /**
2060  * devfreq_recommended_opp() - Helper function to get proper OPP for the
2061  *                           freq value given to target callback.
2062  * @dev:        The devfreq user device. (parent of devfreq)
2063  * @freq:       The frequency given to target function
2064  * @flags:      Flags handed from devfreq framework.
2065  *
2066  * The callers are required to call dev_pm_opp_put() for the returned OPP after
2067  * use.
2068  */
2069 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
2070                                            unsigned long *freq,
2071                                            u32 flags)
2072 {
2073         struct dev_pm_opp *opp;
2074
2075         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
2076                 /* The freq is an upper bound. opp should be lower */
2077                 opp = dev_pm_opp_find_freq_floor_indexed(dev, freq, 0);
2078
2079                 /* If not available, use the closest opp */
2080                 if (opp == ERR_PTR(-ERANGE))
2081                         opp = dev_pm_opp_find_freq_ceil_indexed(dev, freq, 0);
2082         } else {
2083                 /* The freq is an lower bound. opp should be higher */
2084                 opp = dev_pm_opp_find_freq_ceil_indexed(dev, freq, 0);
2085
2086                 /* If not available, use the closest opp */
2087                 if (opp == ERR_PTR(-ERANGE))
2088                         opp = dev_pm_opp_find_freq_floor_indexed(dev, freq, 0);
2089         }
2090
2091         return opp;
2092 }
2093 EXPORT_SYMBOL(devfreq_recommended_opp);
2094
2095 /**
2096  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
2097  *                                   for any changes in the OPP availability
2098  *                                   changes
2099  * @dev:        The devfreq user device. (parent of devfreq)
2100  * @devfreq:    The devfreq object.
2101  */
2102 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
2103 {
2104         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
2105 }
2106 EXPORT_SYMBOL(devfreq_register_opp_notifier);
2107
2108 /**
2109  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
2110  *                                     notified for any changes in the OPP
2111  *                                     availability changes anymore.
2112  * @dev:        The devfreq user device. (parent of devfreq)
2113  * @devfreq:    The devfreq object.
2114  *
2115  * At exit() callback of devfreq_dev_profile, this must be included if
2116  * devfreq_recommended_opp is used.
2117  */
2118 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
2119 {
2120         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
2121 }
2122 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
2123
2124 static void devm_devfreq_opp_release(struct device *dev, void *res)
2125 {
2126         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
2127 }
2128
2129 /**
2130  * devm_devfreq_register_opp_notifier() - Resource-managed
2131  *                                        devfreq_register_opp_notifier()
2132  * @dev:        The devfreq user device. (parent of devfreq)
2133  * @devfreq:    The devfreq object.
2134  */
2135 int devm_devfreq_register_opp_notifier(struct device *dev,
2136                                        struct devfreq *devfreq)
2137 {
2138         struct devfreq **ptr;
2139         int ret;
2140
2141         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
2142         if (!ptr)
2143                 return -ENOMEM;
2144
2145         ret = devfreq_register_opp_notifier(dev, devfreq);
2146         if (ret) {
2147                 devres_free(ptr);
2148                 return ret;
2149         }
2150
2151         *ptr = devfreq;
2152         devres_add(dev, ptr);
2153
2154         return 0;
2155 }
2156 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2157
2158 /**
2159  * devm_devfreq_unregister_opp_notifier() - Resource-managed
2160  *                                          devfreq_unregister_opp_notifier()
2161  * @dev:        The devfreq user device. (parent of devfreq)
2162  * @devfreq:    The devfreq object.
2163  */
2164 void devm_devfreq_unregister_opp_notifier(struct device *dev,
2165                                          struct devfreq *devfreq)
2166 {
2167         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2168                                devm_devfreq_dev_match, devfreq));
2169 }
2170 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2171
2172 /**
2173  * devfreq_register_notifier() - Register a driver with devfreq
2174  * @devfreq:    The devfreq object.
2175  * @nb:         The notifier block to register.
2176  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2177  */
2178 int devfreq_register_notifier(struct devfreq *devfreq,
2179                               struct notifier_block *nb,
2180                               unsigned int list)
2181 {
2182         int ret = 0;
2183
2184         if (!devfreq)
2185                 return -EINVAL;
2186
2187         switch (list) {
2188         case DEVFREQ_TRANSITION_NOTIFIER:
2189                 ret = srcu_notifier_chain_register(
2190                                 &devfreq->transition_notifier_list, nb);
2191                 break;
2192         default:
2193                 ret = -EINVAL;
2194         }
2195
2196         return ret;
2197 }
2198 EXPORT_SYMBOL(devfreq_register_notifier);
2199
2200 /*
2201  * devfreq_unregister_notifier() - Unregister a driver with devfreq
2202  * @devfreq:    The devfreq object.
2203  * @nb:         The notifier block to be unregistered.
2204  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2205  */
2206 int devfreq_unregister_notifier(struct devfreq *devfreq,
2207                                 struct notifier_block *nb,
2208                                 unsigned int list)
2209 {
2210         int ret = 0;
2211
2212         if (!devfreq)
2213                 return -EINVAL;
2214
2215         switch (list) {
2216         case DEVFREQ_TRANSITION_NOTIFIER:
2217                 ret = srcu_notifier_chain_unregister(
2218                                 &devfreq->transition_notifier_list, nb);
2219                 break;
2220         default:
2221                 ret = -EINVAL;
2222         }
2223
2224         return ret;
2225 }
2226 EXPORT_SYMBOL(devfreq_unregister_notifier);
2227
2228 struct devfreq_notifier_devres {
2229         struct devfreq *devfreq;
2230         struct notifier_block *nb;
2231         unsigned int list;
2232 };
2233
2234 static void devm_devfreq_notifier_release(struct device *dev, void *res)
2235 {
2236         struct devfreq_notifier_devres *this = res;
2237
2238         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2239 }
2240
2241 /**
2242  * devm_devfreq_register_notifier()
2243  *      - Resource-managed devfreq_register_notifier()
2244  * @dev:        The devfreq user device. (parent of devfreq)
2245  * @devfreq:    The devfreq object.
2246  * @nb:         The notifier block to be unregistered.
2247  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2248  */
2249 int devm_devfreq_register_notifier(struct device *dev,
2250                                 struct devfreq *devfreq,
2251                                 struct notifier_block *nb,
2252                                 unsigned int list)
2253 {
2254         struct devfreq_notifier_devres *ptr;
2255         int ret;
2256
2257         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2258                                 GFP_KERNEL);
2259         if (!ptr)
2260                 return -ENOMEM;
2261
2262         ret = devfreq_register_notifier(devfreq, nb, list);
2263         if (ret) {
2264                 devres_free(ptr);
2265                 return ret;
2266         }
2267
2268         ptr->devfreq = devfreq;
2269         ptr->nb = nb;
2270         ptr->list = list;
2271         devres_add(dev, ptr);
2272
2273         return 0;
2274 }
2275 EXPORT_SYMBOL(devm_devfreq_register_notifier);
2276
2277 /**
2278  * devm_devfreq_unregister_notifier()
2279  *      - Resource-managed devfreq_unregister_notifier()
2280  * @dev:        The devfreq user device. (parent of devfreq)
2281  * @devfreq:    The devfreq object.
2282  * @nb:         The notifier block to be unregistered.
2283  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2284  */
2285 void devm_devfreq_unregister_notifier(struct device *dev,
2286                                       struct devfreq *devfreq,
2287                                       struct notifier_block *nb,
2288                                       unsigned int list)
2289 {
2290         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2291                                devm_devfreq_dev_match, devfreq));
2292 }
2293 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);