drivers/devfreq/devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   4  *          for Non-CPU Devices.
   5  *
   6  * Copyright (C) 2011 Samsung Electronics
   7  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/kmod.h>
  12 #include <linux/sched.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/devfreq_cooling.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/export.h>
  19 #include <linux/slab.h>
  20 #include <linux/stat.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/devfreq.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/hrtimer.h>
  28 #include <linux/of.h>
  29 #include <linux/pm_qos.h>
  30 #include <linux/units.h>
  31 #include "governor.h"
  32
  33 #define CREATE_TRACE_POINTS
  34 #include <trace/events/devfreq.h>
  35
  36 #define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
  37 #define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
  38
  39 static struct class *devfreq_class;
  40 static struct dentry *devfreq_debugfs;
  41
  42 /*
  43  * devfreq core provides delayed work based load monitoring helper
  44  * functions. Governors can use these or can implement their own
  45  * monitoring mechanism.
  46  */
  47 static struct workqueue_struct *devfreq_wq;
  48
  49 /* The list of all device-devfreq governors */
  50 static LIST_HEAD(devfreq_governor_list);
  51 /* The list of all device-devfreq */
  52 static LIST_HEAD(devfreq_list);
  53 static DEFINE_MUTEX(devfreq_list_lock);
  54
  55 static const char timer_name[][DEVFREQ_NAME_LEN] = {
  56         [DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
  57         [DEVFREQ_TIMER_DELAYED] = { "delayed" },
  58 };
  59
  60 /**
  61  * find_device_devfreq() - find devfreq struct using device pointer
  62  * @dev:        device pointer used to lookup device devfreq.
  63  *
  64  * Search the list of device devfreqs and return the matched device's
  65  * devfreq info. devfreq_list_lock should be held by the caller.
  66  */
  67 static struct devfreq *find_device_devfreq(struct device *dev)
  68 {
  69         struct devfreq *tmp_devfreq;
  70
  71         lockdep_assert_held(&devfreq_list_lock);
  72
  73         if (IS_ERR_OR_NULL(dev)) {
  74                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  75                 return ERR_PTR(-EINVAL);
  76         }
  77
  78         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  79                 if (tmp_devfreq->dev.parent == dev)
  80                         return tmp_devfreq;
  81         }
  82
  83         return ERR_PTR(-ENODEV);
  84 }
  85
  86 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  87 {
  88         struct dev_pm_opp *opp;
  89         unsigned long min_freq = 0;
  90
  91         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  92         if (IS_ERR(opp))
  93                 min_freq = 0;
  94         else
  95                 dev_pm_opp_put(opp);
  96
  97         return min_freq;
  98 }
  99
 100 static unsigned long find_available_max_freq(struct devfreq *devfreq)
 101 {
 102         struct dev_pm_opp *opp;
 103         unsigned long max_freq = ULONG_MAX;
 104
 105         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
 106         if (IS_ERR(opp))
 107                 max_freq = 0;
 108         else
 109                 dev_pm_opp_put(opp);
 110
 111         return max_freq;
 112 }
 113
 114 /**
 115  * devfreq_get_freq_range() - Get the current freq range
 116  * @devfreq:    the devfreq instance
 117  * @min_freq:   the min frequency
 118  * @max_freq:   the max frequency
 119  *
 120  * This takes into consideration all constraints.
 121  */
 122 void devfreq_get_freq_range(struct devfreq *devfreq,
 123                             unsigned long *min_freq,
 124                             unsigned long *max_freq)
 125 {
 126         unsigned long *freq_table = devfreq->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(devfreq->dev.parent, &freq);
 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         queue_delayed_work(devfreq_wq, &devfreq->work,
 465                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 466         mutex_unlock(&devfreq->lock);
 467
 468         trace_devfreq_monitor(devfreq);
 469 }
 470
 471 /**
 472  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 473  * @devfreq:    the devfreq instance.
 474  *
 475  * Helper function for starting devfreq device load monitoring. By default,
 476  * deferrable timer is used for load monitoring. But the users can change this
 477  * behavior using the "timer" type in devfreq_dev_profile. This function will be
 478  * called by devfreq governor in response to the DEVFREQ_GOV_START event
 479  * generated while adding a device to the devfreq framework.
 480  */
 481 void devfreq_monitor_start(struct devfreq *devfreq)
 482 {
 483         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 484                 return;
 485
 486         switch (devfreq->profile->timer) {
 487         case DEVFREQ_TIMER_DEFERRABLE:
 488                 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 489                 break;
 490         case DEVFREQ_TIMER_DELAYED:
 491                 INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
 492                 break;
 493         default:
 494                 return;
 495         }
 496
 497         if (devfreq->profile->polling_ms)
 498                 queue_delayed_work(devfreq_wq, &devfreq->work,
 499                         msecs_to_jiffies(devfreq->profile->polling_ms));
 500 }
 501 EXPORT_SYMBOL(devfreq_monitor_start);
 502
 503 /**
 504  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 505  * @devfreq:    the devfreq instance.
 506  *
 507  * Helper function to stop devfreq device load monitoring. Function
 508  * to be called from governor in response to DEVFREQ_GOV_STOP
 509  * event when device is removed from devfreq framework.
 510  */
 511 void devfreq_monitor_stop(struct devfreq *devfreq)
 512 {
 513         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 514                 return;
 515
 516         cancel_delayed_work_sync(&devfreq->work);
 517 }
 518 EXPORT_SYMBOL(devfreq_monitor_stop);
 519
 520 /**
 521  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 522  * @devfreq:    the devfreq instance.
 523  *
 524  * Helper function to suspend devfreq device load monitoring. Function
 525  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 526  * event or when polling interval is set to zero.
 527  *
 528  * Note: Though this function is same as devfreq_monitor_stop(),
 529  * intentionally kept separate to provide hooks for collecting
 530  * transition statistics.
 531  */
 532 void devfreq_monitor_suspend(struct devfreq *devfreq)
 533 {
 534         mutex_lock(&devfreq->lock);
 535         if (devfreq->stop_polling) {
 536                 mutex_unlock(&devfreq->lock);
 537                 return;
 538         }
 539
 540         devfreq_update_status(devfreq, devfreq->previous_freq);
 541         devfreq->stop_polling = true;
 542         mutex_unlock(&devfreq->lock);
 543
 544         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 545                 return;
 546
 547         cancel_delayed_work_sync(&devfreq->work);
 548 }
 549 EXPORT_SYMBOL(devfreq_monitor_suspend);
 550
 551 /**
 552  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 553  * @devfreq:    the devfreq instance.
 554  *
 555  * Helper function to resume devfreq device load monitoring. Function
 556  * to be called from governor in response to DEVFREQ_GOV_RESUME
 557  * event or when polling interval is set to non-zero.
 558  */
 559 void devfreq_monitor_resume(struct devfreq *devfreq)
 560 {
 561         unsigned long freq;
 562
 563         mutex_lock(&devfreq->lock);
 564
 565         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 566                 goto out_update;
 567
 568         if (!devfreq->stop_polling)
 569                 goto out;
 570
 571         if (!delayed_work_pending(&devfreq->work) &&
 572                         devfreq->profile->polling_ms)
 573                 queue_delayed_work(devfreq_wq, &devfreq->work,
 574                         msecs_to_jiffies(devfreq->profile->polling_ms));
 575
 576 out_update:
 577         devfreq->stats.last_update = get_jiffies_64();
 578         devfreq->stop_polling = false;
 579
 580         if (devfreq->profile->get_cur_freq &&
 581                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 582                 devfreq->previous_freq = freq;
 583
 584 out:
 585         mutex_unlock(&devfreq->lock);
 586 }
 587 EXPORT_SYMBOL(devfreq_monitor_resume);
 588
 589 /**
 590  * devfreq_update_interval() - Update device devfreq monitoring interval
 591  * @devfreq:    the devfreq instance.
 592  * @delay:      new polling interval to be set.
 593  *
 594  * Helper function to set new load monitoring polling interval. Function
 595  * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 596  */
 597 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 598 {
 599         unsigned int cur_delay = devfreq->profile->polling_ms;
 600         unsigned int new_delay = *delay;
 601
 602         mutex_lock(&devfreq->lock);
 603         devfreq->profile->polling_ms = new_delay;
 604
 605         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 606                 goto out;
 607
 608         if (devfreq->stop_polling)
 609                 goto out;
 610
 611         /* if new delay is zero, stop polling */
 612         if (!new_delay) {
 613                 mutex_unlock(&devfreq->lock);
 614                 cancel_delayed_work_sync(&devfreq->work);
 615                 return;
 616         }
 617
 618         /* if current delay is zero, start polling with new delay */
 619         if (!cur_delay) {
 620                 queue_delayed_work(devfreq_wq, &devfreq->work,
 621                         msecs_to_jiffies(devfreq->profile->polling_ms));
 622                 goto out;
 623         }
 624
 625         /* if current delay is greater than new delay, restart polling */
 626         if (cur_delay > new_delay) {
 627                 mutex_unlock(&devfreq->lock);
 628                 cancel_delayed_work_sync(&devfreq->work);
 629                 mutex_lock(&devfreq->lock);
 630                 if (!devfreq->stop_polling)
 631                         queue_delayed_work(devfreq_wq, &devfreq->work,
 632                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 633         }
 634 out:
 635         mutex_unlock(&devfreq->lock);
 636 }
 637 EXPORT_SYMBOL(devfreq_update_interval);
 638
 639 /**
 640  * devfreq_notifier_call() - Notify that the device frequency requirements
 641  *                           has been changed out of devfreq framework.
 642  * @nb:         the notifier_block (supposed to be devfreq->nb)
 643  * @type:       not used
 644  * @devp:       not used
 645  *
 646  * Called by a notifier that uses devfreq->nb.
 647  */
 648 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 649                                  void *devp)
 650 {
 651         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 652         int err = -EINVAL;
 653
 654         mutex_lock(&devfreq->lock);
 655
 656         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 657         if (!devfreq->scaling_min_freq)
 658                 goto out;
 659
 660         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 661         if (!devfreq->scaling_max_freq) {
 662                 devfreq->scaling_max_freq = ULONG_MAX;
 663                 goto out;
 664         }
 665
 666         err = update_devfreq(devfreq);
 667
 668 out:
 669         mutex_unlock(&devfreq->lock);
 670         if (err)
 671                 dev_err(devfreq->dev.parent,
 672                         "failed to update frequency from OPP notifier (%d)\n",
 673                         err);
 674
 675         return NOTIFY_OK;
 676 }
 677
 678 /**
 679  * qos_notifier_call() - Common handler for QoS constraints.
 680  * @devfreq:    the devfreq instance.
 681  */
 682 static int qos_notifier_call(struct devfreq *devfreq)
 683 {
 684         int err;
 685
 686         mutex_lock(&devfreq->lock);
 687         err = update_devfreq(devfreq);
 688         mutex_unlock(&devfreq->lock);
 689         if (err)
 690                 dev_err(devfreq->dev.parent,
 691                         "failed to update frequency from PM QoS (%d)\n",
 692                         err);
 693
 694         return NOTIFY_OK;
 695 }
 696
 697 /**
 698  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 699  * @nb:         Should be devfreq->nb_min
 700  * @val:        not used
 701  * @ptr:        not used
 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  * @val:        not used
 713  * @ptr:        not used
 714  */
 715 static int qos_max_notifier_call(struct notifier_block *nb,
 716                                          unsigned long val, void *ptr)
 717 {
 718         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 719 }
 720
 721 /**
 722  * devfreq_dev_release() - Callback for struct device to release the device.
 723  * @dev:        the devfreq device
 724  *
 725  * Remove devfreq from the list and release its resources.
 726  */
 727 static void devfreq_dev_release(struct device *dev)
 728 {
 729         struct devfreq *devfreq = to_devfreq(dev);
 730         int err;
 731
 732         mutex_lock(&devfreq_list_lock);
 733         list_del(&devfreq->node);
 734         mutex_unlock(&devfreq_list_lock);
 735
 736         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 737                                          DEV_PM_QOS_MAX_FREQUENCY);
 738         if (err && err != -ENOENT)
 739                 dev_warn(dev->parent,
 740                         "Failed to remove max_freq notifier: %d\n", err);
 741         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 742                                          DEV_PM_QOS_MIN_FREQUENCY);
 743         if (err && err != -ENOENT)
 744                 dev_warn(dev->parent,
 745                         "Failed to remove min_freq notifier: %d\n", err);
 746
 747         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 748                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 749                 if (err < 0)
 750                         dev_warn(dev->parent,
 751                                 "Failed to remove max_freq request: %d\n", err);
 752         }
 753         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 754                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 755                 if (err < 0)
 756                         dev_warn(dev->parent,
 757                                 "Failed to remove min_freq request: %d\n", err);
 758         }
 759
 760         if (devfreq->profile->exit)
 761                 devfreq->profile->exit(devfreq->dev.parent);
 762
 763         if (devfreq->opp_table)
 764                 dev_pm_opp_put_opp_table(devfreq->opp_table);
 765
 766         mutex_destroy(&devfreq->lock);
 767         srcu_cleanup_notifier_head(&devfreq->transition_notifier_list);
 768         kfree(devfreq);
 769 }
 770
 771 static void create_sysfs_files(struct devfreq *devfreq,
 772                                 const struct devfreq_governor *gov);
 773 static void remove_sysfs_files(struct devfreq *devfreq,
 774                                 const struct devfreq_governor *gov);
 775
 776 /**
 777  * devfreq_add_device() - Add devfreq feature to the device
 778  * @dev:        the device to add devfreq feature.
 779  * @profile:    device-specific profile to run devfreq.
 780  * @governor_name:      name of the policy to choose frequency.
 781  * @data:       devfreq driver pass to governors, governor should not change it.
 782  */
 783 struct devfreq *devfreq_add_device(struct device *dev,
 784                                    struct devfreq_dev_profile *profile,
 785                                    const char *governor_name,
 786                                    void *data)
 787 {
 788         struct devfreq *devfreq;
 789         struct devfreq_governor *governor;
 790         unsigned long min_freq, max_freq;
 791         int err = 0;
 792
 793         if (!dev || !profile || !governor_name) {
 794                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 795                 return ERR_PTR(-EINVAL);
 796         }
 797
 798         mutex_lock(&devfreq_list_lock);
 799         devfreq = find_device_devfreq(dev);
 800         mutex_unlock(&devfreq_list_lock);
 801         if (!IS_ERR(devfreq)) {
 802                 dev_err(dev, "%s: devfreq device already exists!\n",
 803                         __func__);
 804                 err = -EINVAL;
 805                 goto err_out;
 806         }
 807
 808         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 809         if (!devfreq) {
 810                 err = -ENOMEM;
 811                 goto err_out;
 812         }
 813
 814         mutex_init(&devfreq->lock);
 815         mutex_lock(&devfreq->lock);
 816         devfreq->dev.parent = dev;
 817         devfreq->dev.class = devfreq_class;
 818         devfreq->dev.release = devfreq_dev_release;
 819         INIT_LIST_HEAD(&devfreq->node);
 820         devfreq->profile = profile;
 821         devfreq->previous_freq = profile->initial_freq;
 822         devfreq->last_status.current_frequency = profile->initial_freq;
 823         devfreq->data = data;
 824         devfreq->nb.notifier_call = devfreq_notifier_call;
 825
 826         if (devfreq->profile->timer < 0
 827                 || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 828                 mutex_unlock(&devfreq->lock);
 829                 err = -EINVAL;
 830                 goto err_dev;
 831         }
 832
 833         if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
 834                 mutex_unlock(&devfreq->lock);
 835                 err = set_freq_table(devfreq);
 836                 if (err < 0)
 837                         goto err_dev;
 838                 mutex_lock(&devfreq->lock);
 839         } else {
 840                 devfreq->freq_table = devfreq->profile->freq_table;
 841                 devfreq->max_state = devfreq->profile->max_state;
 842         }
 843
 844         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 845         if (!devfreq->scaling_min_freq) {
 846                 mutex_unlock(&devfreq->lock);
 847                 err = -EINVAL;
 848                 goto err_dev;
 849         }
 850
 851         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 852         if (!devfreq->scaling_max_freq) {
 853                 mutex_unlock(&devfreq->lock);
 854                 err = -EINVAL;
 855                 goto err_dev;
 856         }
 857
 858         devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 859
 860         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 861         devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
 862         if (IS_ERR(devfreq->opp_table))
 863                 devfreq->opp_table = NULL;
 864
 865         atomic_set(&devfreq->suspend_count, 0);
 866
 867         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 868         err = device_register(&devfreq->dev);
 869         if (err) {
 870                 mutex_unlock(&devfreq->lock);
 871                 put_device(&devfreq->dev);
 872                 goto err_out;
 873         }
 874
 875         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 876                         array3_size(sizeof(unsigned int),
 877                                     devfreq->max_state,
 878                                     devfreq->max_state),
 879                         GFP_KERNEL);
 880         if (!devfreq->stats.trans_table) {
 881                 mutex_unlock(&devfreq->lock);
 882                 err = -ENOMEM;
 883                 goto err_devfreq;
 884         }
 885
 886         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 887                         devfreq->max_state,
 888                         sizeof(*devfreq->stats.time_in_state),
 889                         GFP_KERNEL);
 890         if (!devfreq->stats.time_in_state) {
 891                 mutex_unlock(&devfreq->lock);
 892                 err = -ENOMEM;
 893                 goto err_devfreq;
 894         }
 895
 896         devfreq->stats.total_trans = 0;
 897         devfreq->stats.last_update = get_jiffies_64();
 898
 899         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 900
 901         mutex_unlock(&devfreq->lock);
 902
 903         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 904                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 905         if (err < 0)
 906                 goto err_devfreq;
 907         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 908                                      DEV_PM_QOS_MAX_FREQUENCY,
 909                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 910         if (err < 0)
 911                 goto err_devfreq;
 912
 913         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 914         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
 915                                       DEV_PM_QOS_MIN_FREQUENCY);
 916         if (err)
 917                 goto err_devfreq;
 918
 919         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 920         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
 921                                       DEV_PM_QOS_MAX_FREQUENCY);
 922         if (err)
 923                 goto err_devfreq;
 924
 925         mutex_lock(&devfreq_list_lock);
 926
 927         governor = try_then_request_governor(governor_name);
 928         if (IS_ERR(governor)) {
 929                 dev_err(dev, "%s: Unable to find governor for the device\n",
 930                         __func__);
 931                 err = PTR_ERR(governor);
 932                 goto err_init;
 933         }
 934
 935         devfreq->governor = governor;
 936         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 937                                                 NULL);
 938         if (err) {
 939                 dev_err_probe(dev, err,
 940                         "%s: Unable to start governor for the device\n",
 941                          __func__);
 942                 goto err_init;
 943         }
 944         create_sysfs_files(devfreq, devfreq->governor);
 945
 946         list_add(&devfreq->node, &devfreq_list);
 947
 948         mutex_unlock(&devfreq_list_lock);
 949
 950         if (devfreq->profile->is_cooling_device) {
 951                 devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
 952                 if (IS_ERR(devfreq->cdev))
 953                         devfreq->cdev = NULL;
 954         }
 955
 956         return devfreq;
 957
 958 err_init:
 959         mutex_unlock(&devfreq_list_lock);
 960 err_devfreq:
 961         devfreq_remove_device(devfreq);
 962         devfreq = NULL;
 963 err_dev:
 964         kfree(devfreq);
 965 err_out:
 966         return ERR_PTR(err);
 967 }
 968 EXPORT_SYMBOL(devfreq_add_device);
 969
 970 /**
 971  * devfreq_remove_device() - Remove devfreq feature from a device.
 972  * @devfreq:    the devfreq instance to be removed
 973  *
 974  * The opposite of devfreq_add_device().
 975  */
 976 int devfreq_remove_device(struct devfreq *devfreq)
 977 {
 978         if (!devfreq)
 979                 return -EINVAL;
 980
 981         devfreq_cooling_unregister(devfreq->cdev);
 982
 983         if (devfreq->governor) {
 984                 devfreq->governor->event_handler(devfreq,
 985                                                  DEVFREQ_GOV_STOP, NULL);
 986                 remove_sysfs_files(devfreq, devfreq->governor);
 987         }
 988
 989         device_unregister(&devfreq->dev);
 990
 991         return 0;
 992 }
 993 EXPORT_SYMBOL(devfreq_remove_device);
 994
 995 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 996 {
 997         struct devfreq **r = res;
 998
 999         if (WARN_ON(!r || !*r))
1000                 return 0;
1001
1002         return *r == data;
1003 }
1004
1005 static void devm_devfreq_dev_release(struct device *dev, void *res)
1006 {
1007         devfreq_remove_device(*(struct devfreq **)res);
1008 }
1009
1010 /**
1011  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
1012  * @dev:        the device to add devfreq feature.
1013  * @profile:    device-specific profile to run devfreq.
1014  * @governor_name:      name of the policy to choose frequency.
1015  * @data:        devfreq driver pass to governors, governor should not change it.
1016  *
1017  * This function manages automatically the memory of devfreq device using device
1018  * resource management and simplify the free operation for memory of devfreq
1019  * device.
1020  */
1021 struct devfreq *devm_devfreq_add_device(struct device *dev,
1022                                         struct devfreq_dev_profile *profile,
1023                                         const char *governor_name,
1024                                         void *data)
1025 {
1026         struct devfreq **ptr, *devfreq;
1027
1028         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
1029         if (!ptr)
1030                 return ERR_PTR(-ENOMEM);
1031
1032         devfreq = devfreq_add_device(dev, profile, governor_name, data);
1033         if (IS_ERR(devfreq)) {
1034                 devres_free(ptr);
1035                 return devfreq;
1036         }
1037
1038         *ptr = devfreq;
1039         devres_add(dev, ptr);
1040
1041         return devfreq;
1042 }
1043 EXPORT_SYMBOL(devm_devfreq_add_device);
1044
1045 #ifdef CONFIG_OF
1046 /*
1047  * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1048  * @node - pointer to device_node
1049  *
1050  * return the instance of devfreq device
1051  */
1052 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1053 {
1054         struct devfreq *devfreq;
1055
1056         if (!node)
1057                 return ERR_PTR(-EINVAL);
1058
1059         mutex_lock(&devfreq_list_lock);
1060         list_for_each_entry(devfreq, &devfreq_list, node) {
1061                 if (devfreq->dev.parent
1062                         && device_match_of_node(devfreq->dev.parent, node)) {
1063                         mutex_unlock(&devfreq_list_lock);
1064                         return devfreq;
1065                 }
1066         }
1067         mutex_unlock(&devfreq_list_lock);
1068
1069         return ERR_PTR(-ENODEV);
1070 }
1071
1072 /*
1073  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1074  * @dev - instance to the given device
1075  * @phandle_name - name of property holding a phandle value
1076  * @index - index into list of devfreq
1077  *
1078  * return the instance of devfreq device
1079  */
1080 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1081                                         const char *phandle_name, int index)
1082 {
1083         struct device_node *node;
1084         struct devfreq *devfreq;
1085
1086         if (!dev || !phandle_name)
1087                 return ERR_PTR(-EINVAL);
1088
1089         if (!dev->of_node)
1090                 return ERR_PTR(-EINVAL);
1091
1092         node = of_parse_phandle(dev->of_node, phandle_name, index);
1093         if (!node)
1094                 return ERR_PTR(-ENODEV);
1095
1096         devfreq = devfreq_get_devfreq_by_node(node);
1097         of_node_put(node);
1098
1099         return devfreq;
1100 }
1101
1102 #else
1103 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1104 {
1105         return ERR_PTR(-ENODEV);
1106 }
1107
1108 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1109                                         const char *phandle_name, int index)
1110 {
1111         return ERR_PTR(-ENODEV);
1112 }
1113 #endif /* CONFIG_OF */
1114 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1115 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1116
1117 /**
1118  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1119  * @dev:        the device from which to remove devfreq feature.
1120  * @devfreq:    the devfreq instance to be removed
1121  */
1122 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1123 {
1124         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1125                                devm_devfreq_dev_match, devfreq));
1126 }
1127 EXPORT_SYMBOL(devm_devfreq_remove_device);
1128
1129 /**
1130  * devfreq_suspend_device() - Suspend devfreq of a device.
1131  * @devfreq: the devfreq instance to be suspended
1132  *
1133  * This function is intended to be called by the pm callbacks
1134  * (e.g., runtime_suspend, suspend) of the device driver that
1135  * holds the devfreq.
1136  */
1137 int devfreq_suspend_device(struct devfreq *devfreq)
1138 {
1139         int ret;
1140
1141         if (!devfreq)
1142                 return -EINVAL;
1143
1144         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1145                 return 0;
1146
1147         if (devfreq->governor) {
1148                 ret = devfreq->governor->event_handler(devfreq,
1149                                         DEVFREQ_GOV_SUSPEND, NULL);
1150                 if (ret)
1151                         return ret;
1152         }
1153
1154         if (devfreq->suspend_freq) {
1155                 mutex_lock(&devfreq->lock);
1156                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1157                 mutex_unlock(&devfreq->lock);
1158                 if (ret)
1159                         return ret;
1160         }
1161
1162         return 0;
1163 }
1164 EXPORT_SYMBOL(devfreq_suspend_device);
1165
1166 /**
1167  * devfreq_resume_device() - Resume devfreq of a device.
1168  * @devfreq: the devfreq instance to be resumed
1169  *
1170  * This function is intended to be called by the pm callbacks
1171  * (e.g., runtime_resume, resume) of the device driver that
1172  * holds the devfreq.
1173  */
1174 int devfreq_resume_device(struct devfreq *devfreq)
1175 {
1176         int ret;
1177
1178         if (!devfreq)
1179                 return -EINVAL;
1180
1181         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1182                 return 0;
1183
1184         if (devfreq->resume_freq) {
1185                 mutex_lock(&devfreq->lock);
1186                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1187                 mutex_unlock(&devfreq->lock);
1188                 if (ret)
1189                         return ret;
1190         }
1191
1192         if (devfreq->governor) {
1193                 ret = devfreq->governor->event_handler(devfreq,
1194                                         DEVFREQ_GOV_RESUME, NULL);
1195                 if (ret)
1196                         return ret;
1197         }
1198
1199         return 0;
1200 }
1201 EXPORT_SYMBOL(devfreq_resume_device);
1202
1203 /**
1204  * devfreq_suspend() - Suspend devfreq governors and devices
1205  *
1206  * Called during system wide Suspend/Hibernate cycles for suspending governors
1207  * and devices preserving the state for resume. On some platforms the devfreq
1208  * device must have precise state (frequency) after resume in order to provide
1209  * fully operating setup.
1210  */
1211 void devfreq_suspend(void)
1212 {
1213         struct devfreq *devfreq;
1214         int ret;
1215
1216         mutex_lock(&devfreq_list_lock);
1217         list_for_each_entry(devfreq, &devfreq_list, node) {
1218                 ret = devfreq_suspend_device(devfreq);
1219                 if (ret)
1220                         dev_err(&devfreq->dev,
1221                                 "failed to suspend devfreq device\n");
1222         }
1223         mutex_unlock(&devfreq_list_lock);
1224 }
1225
1226 /**
1227  * devfreq_resume() - Resume devfreq governors and devices
1228  *
1229  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1230  * devices that are suspended with devfreq_suspend().
1231  */
1232 void devfreq_resume(void)
1233 {
1234         struct devfreq *devfreq;
1235         int ret;
1236
1237         mutex_lock(&devfreq_list_lock);
1238         list_for_each_entry(devfreq, &devfreq_list, node) {
1239                 ret = devfreq_resume_device(devfreq);
1240                 if (ret)
1241                         dev_warn(&devfreq->dev,
1242                                  "failed to resume devfreq device\n");
1243         }
1244         mutex_unlock(&devfreq_list_lock);
1245 }
1246
1247 /**
1248  * devfreq_add_governor() - Add devfreq governor
1249  * @governor:   the devfreq governor to be added
1250  */
1251 int devfreq_add_governor(struct devfreq_governor *governor)
1252 {
1253         struct devfreq_governor *g;
1254         struct devfreq *devfreq;
1255         int err = 0;
1256
1257         if (!governor) {
1258                 pr_err("%s: Invalid parameters.\n", __func__);
1259                 return -EINVAL;
1260         }
1261
1262         mutex_lock(&devfreq_list_lock);
1263         g = find_devfreq_governor(governor->name);
1264         if (!IS_ERR(g)) {
1265                 pr_err("%s: governor %s already registered\n", __func__,
1266                        g->name);
1267                 err = -EINVAL;
1268                 goto err_out;
1269         }
1270
1271         list_add(&governor->node, &devfreq_governor_list);
1272
1273         list_for_each_entry(devfreq, &devfreq_list, node) {
1274                 int ret = 0;
1275                 struct device *dev = devfreq->dev.parent;
1276
1277                 if (!strncmp(devfreq->governor->name, governor->name,
1278                              DEVFREQ_NAME_LEN)) {
1279                         /* The following should never occur */
1280                         if (devfreq->governor) {
1281                                 dev_warn(dev,
1282                                          "%s: Governor %s already present\n",
1283                                          __func__, devfreq->governor->name);
1284                                 ret = devfreq->governor->event_handler(devfreq,
1285                                                         DEVFREQ_GOV_STOP, NULL);
1286                                 if (ret) {
1287                                         dev_warn(dev,
1288                                                  "%s: Governor %s stop = %d\n",
1289                                                  __func__,
1290                                                  devfreq->governor->name, ret);
1291                                 }
1292                                 /* Fall through */
1293                         }
1294                         devfreq->governor = governor;
1295                         ret = devfreq->governor->event_handler(devfreq,
1296                                                 DEVFREQ_GOV_START, NULL);
1297                         if (ret) {
1298                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1299                                          __func__, devfreq->governor->name,
1300                                          ret);
1301                         }
1302                 }
1303         }
1304
1305 err_out:
1306         mutex_unlock(&devfreq_list_lock);
1307
1308         return err;
1309 }
1310 EXPORT_SYMBOL(devfreq_add_governor);
1311
1312 static void devm_devfreq_remove_governor(void *governor)
1313 {
1314         WARN_ON(devfreq_remove_governor(governor));
1315 }
1316
1317 /**
1318  * devm_devfreq_add_governor() - Add devfreq governor
1319  * @dev:        device which adds devfreq governor
1320  * @governor:   the devfreq governor to be added
1321  *
1322  * This is a resource-managed variant of devfreq_add_governor().
1323  */
1324 int devm_devfreq_add_governor(struct device *dev,
1325                               struct devfreq_governor *governor)
1326 {
1327         int err;
1328
1329         err = devfreq_add_governor(governor);
1330         if (err)
1331                 return err;
1332
1333         return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
1334                                         governor);
1335 }
1336 EXPORT_SYMBOL(devm_devfreq_add_governor);
1337
1338 /**
1339  * devfreq_remove_governor() - Remove devfreq feature from a device.
1340  * @governor:   the devfreq governor to be removed
1341  */
1342 int devfreq_remove_governor(struct devfreq_governor *governor)
1343 {
1344         struct devfreq_governor *g;
1345         struct devfreq *devfreq;
1346         int err = 0;
1347
1348         if (!governor) {
1349                 pr_err("%s: Invalid parameters.\n", __func__);
1350                 return -EINVAL;
1351         }
1352
1353         mutex_lock(&devfreq_list_lock);
1354         g = find_devfreq_governor(governor->name);
1355         if (IS_ERR(g)) {
1356                 pr_err("%s: governor %s not registered\n", __func__,
1357                        governor->name);
1358                 err = PTR_ERR(g);
1359                 goto err_out;
1360         }
1361         list_for_each_entry(devfreq, &devfreq_list, node) {
1362                 int ret;
1363                 struct device *dev = devfreq->dev.parent;
1364
1365                 if (!strncmp(devfreq->governor->name, governor->name,
1366                              DEVFREQ_NAME_LEN)) {
1367                         /* we should have a devfreq governor! */
1368                         if (!devfreq->governor) {
1369                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1370                                          __func__, governor->name);
1371                                 continue;
1372                                 /* Fall through */
1373                         }
1374                         ret = devfreq->governor->event_handler(devfreq,
1375                                                 DEVFREQ_GOV_STOP, NULL);
1376                         if (ret) {
1377                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1378                                          __func__, devfreq->governor->name,
1379                                          ret);
1380                         }
1381                         devfreq->governor = NULL;
1382                 }
1383         }
1384
1385         list_del(&governor->node);
1386 err_out:
1387         mutex_unlock(&devfreq_list_lock);
1388
1389         return err;
1390 }
1391 EXPORT_SYMBOL(devfreq_remove_governor);
1392
1393 static ssize_t name_show(struct device *dev,
1394                         struct device_attribute *attr, char *buf)
1395 {
1396         struct devfreq *df = to_devfreq(dev);
1397         return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1398 }
1399 static DEVICE_ATTR_RO(name);
1400
1401 static ssize_t governor_show(struct device *dev,
1402                              struct device_attribute *attr, char *buf)
1403 {
1404         struct devfreq *df = to_devfreq(dev);
1405
1406         if (!df->governor)
1407                 return -EINVAL;
1408
1409         return sprintf(buf, "%s\n", df->governor->name);
1410 }
1411
1412 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1413                               const char *buf, size_t count)
1414 {
1415         struct devfreq *df = to_devfreq(dev);
1416         int ret;
1417         char str_governor[DEVFREQ_NAME_LEN + 1];
1418         const struct devfreq_governor *governor, *prev_governor;
1419
1420         if (!df->governor)
1421                 return -EINVAL;
1422
1423         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1424         if (ret != 1)
1425                 return -EINVAL;
1426
1427         mutex_lock(&devfreq_list_lock);
1428         governor = try_then_request_governor(str_governor);
1429         if (IS_ERR(governor)) {
1430                 ret = PTR_ERR(governor);
1431                 goto out;
1432         }
1433         if (df->governor == governor) {
1434                 ret = 0;
1435                 goto out;
1436         } else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
1437                 || IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
1438                 ret = -EINVAL;
1439                 goto out;
1440         }
1441
1442         /*
1443          * Stop the current governor and remove the specific sysfs files
1444          * which depend on current governor.
1445          */
1446         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1447         if (ret) {
1448                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1449                          __func__, df->governor->name, ret);
1450                 goto out;
1451         }
1452         remove_sysfs_files(df, df->governor);
1453
1454         /*
1455          * Start the new governor and create the specific sysfs files
1456          * which depend on the new governor.
1457          */
1458         prev_governor = df->governor;
1459         df->governor = governor;
1460         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1461         if (ret) {
1462                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1463                          __func__, df->governor->name, ret);
1464
1465                 /* Restore previous governor */
1466                 df->governor = prev_governor;
1467                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1468                 if (ret) {
1469                         dev_err(dev,
1470                                 "%s: reverting to Governor %s failed (%d)\n",
1471                                 __func__, prev_governor->name, ret);
1472                         df->governor = NULL;
1473                         goto out;
1474                 }
1475         }
1476
1477         /*
1478          * Create the sysfs files for the new governor. But if failed to start
1479          * the new governor, restore the sysfs files of previous governor.
1480          */
1481         create_sysfs_files(df, df->governor);
1482
1483 out:
1484         mutex_unlock(&devfreq_list_lock);
1485
1486         if (!ret)
1487                 ret = count;
1488         return ret;
1489 }
1490 static DEVICE_ATTR_RW(governor);
1491
1492 static ssize_t available_governors_show(struct device *d,
1493                                         struct device_attribute *attr,
1494                                         char *buf)
1495 {
1496         struct devfreq *df = to_devfreq(d);
1497         ssize_t count = 0;
1498
1499         if (!df->governor)
1500                 return -EINVAL;
1501
1502         mutex_lock(&devfreq_list_lock);
1503
1504         /*
1505          * The devfreq with immutable governor (e.g., passive) shows
1506          * only own governor.
1507          */
1508         if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
1509                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1510                                   "%s ", df->governor->name);
1511         /*
1512          * The devfreq device shows the registered governor except for
1513          * immutable governors such as passive governor .
1514          */
1515         } else {
1516                 struct devfreq_governor *governor;
1517
1518                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1519                         if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
1520                                 continue;
1521                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1522                                            "%s ", governor->name);
1523                 }
1524         }
1525
1526         mutex_unlock(&devfreq_list_lock);
1527
1528         /* Truncate the trailing space */
1529         if (count)
1530                 count--;
1531
1532         count += sprintf(&buf[count], "\n");
1533
1534         return count;
1535 }
1536 static DEVICE_ATTR_RO(available_governors);
1537
1538 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1539                              char *buf)
1540 {
1541         unsigned long freq;
1542         struct devfreq *df = to_devfreq(dev);
1543
1544         if (!df->profile)
1545                 return -EINVAL;
1546
1547         if (df->profile->get_cur_freq &&
1548                 !df->profile->get_cur_freq(df->dev.parent, &freq))
1549                 return sprintf(buf, "%lu\n", freq);
1550
1551         return sprintf(buf, "%lu\n", df->previous_freq);
1552 }
1553 static DEVICE_ATTR_RO(cur_freq);
1554
1555 static ssize_t target_freq_show(struct device *dev,
1556                                 struct device_attribute *attr, char *buf)
1557 {
1558         struct devfreq *df = to_devfreq(dev);
1559
1560         return sprintf(buf, "%lu\n", df->previous_freq);
1561 }
1562 static DEVICE_ATTR_RO(target_freq);
1563
1564 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1565                               const char *buf, size_t count)
1566 {
1567         struct devfreq *df = to_devfreq(dev);
1568         unsigned long value;
1569         int ret;
1570
1571         /*
1572          * Protect against theoretical sysfs writes between
1573          * device_add and dev_pm_qos_add_request
1574          */
1575         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1576                 return -EAGAIN;
1577
1578         ret = sscanf(buf, "%lu", &value);
1579         if (ret != 1)
1580                 return -EINVAL;
1581
1582         /* Round down to kHz for PM QoS */
1583         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1584                                         value / HZ_PER_KHZ);
1585         if (ret < 0)
1586                 return ret;
1587
1588         return count;
1589 }
1590
1591 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1592                              char *buf)
1593 {
1594         struct devfreq *df = to_devfreq(dev);
1595         unsigned long min_freq, max_freq;
1596
1597         mutex_lock(&df->lock);
1598         devfreq_get_freq_range(df, &min_freq, &max_freq);
1599         mutex_unlock(&df->lock);
1600
1601         return sprintf(buf, "%lu\n", min_freq);
1602 }
1603 static DEVICE_ATTR_RW(min_freq);
1604
1605 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1606                               const char *buf, size_t count)
1607 {
1608         struct devfreq *df = to_devfreq(dev);
1609         unsigned long value;
1610         int ret;
1611
1612         /*
1613          * Protect against theoretical sysfs writes between
1614          * device_add and dev_pm_qos_add_request
1615          */
1616         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1617                 return -EINVAL;
1618
1619         ret = sscanf(buf, "%lu", &value);
1620         if (ret != 1)
1621                 return -EINVAL;
1622
1623         /*
1624          * PM QoS frequencies are in kHz so we need to convert. Convert by
1625          * rounding upwards so that the acceptable interval never shrinks.
1626          *
1627          * For example if the user writes "666666666" to sysfs this value will
1628          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1629          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1630          *
1631          * A value of zero means "no limit".
1632          */
1633         if (value)
1634                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1635         else
1636                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1637
1638         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1639         if (ret < 0)
1640                 return ret;
1641
1642         return count;
1643 }
1644
1645 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1646                              char *buf)
1647 {
1648         struct devfreq *df = to_devfreq(dev);
1649         unsigned long min_freq, max_freq;
1650
1651         mutex_lock(&df->lock);
1652         devfreq_get_freq_range(df, &min_freq, &max_freq);
1653         mutex_unlock(&df->lock);
1654
1655         return sprintf(buf, "%lu\n", max_freq);
1656 }
1657 static DEVICE_ATTR_RW(max_freq);
1658
1659 static ssize_t available_frequencies_show(struct device *d,
1660                                           struct device_attribute *attr,
1661                                           char *buf)
1662 {
1663         struct devfreq *df = to_devfreq(d);
1664         ssize_t count = 0;
1665         int i;
1666
1667         if (!df->profile)
1668                 return -EINVAL;
1669
1670         mutex_lock(&df->lock);
1671
1672         for (i = 0; i < df->max_state; i++)
1673                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1674                                 "%lu ", df->freq_table[i]);
1675
1676         mutex_unlock(&df->lock);
1677         /* Truncate the trailing space */
1678         if (count)
1679                 count--;
1680
1681         count += sprintf(&buf[count], "\n");
1682
1683         return count;
1684 }
1685 static DEVICE_ATTR_RO(available_frequencies);
1686
1687 static ssize_t trans_stat_show(struct device *dev,
1688                                struct device_attribute *attr, char *buf)
1689 {
1690         struct devfreq *df = to_devfreq(dev);
1691         ssize_t len;
1692         int i, j;
1693         unsigned int max_state;
1694
1695         if (!df->profile)
1696                 return -EINVAL;
1697         max_state = df->max_state;
1698
1699         if (max_state == 0)
1700                 return sprintf(buf, "Not Supported.\n");
1701
1702         mutex_lock(&df->lock);
1703         if (!df->stop_polling &&
1704                         devfreq_update_status(df, df->previous_freq)) {
1705                 mutex_unlock(&df->lock);
1706                 return 0;
1707         }
1708         mutex_unlock(&df->lock);
1709
1710         len = sprintf(buf, "     From  :   To\n");
1711         len += sprintf(buf + len, "           :");
1712         for (i = 0; i < max_state; i++)
1713                 len += sprintf(buf + len, "%10lu",
1714                                 df->freq_table[i]);
1715
1716         len += sprintf(buf + len, "   time(ms)\n");
1717
1718         for (i = 0; i < max_state; i++) {
1719                 if (df->freq_table[i] == df->previous_freq)
1720                         len += sprintf(buf + len, "*");
1721                 else
1722                         len += sprintf(buf + len, " ");
1723
1724                 len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
1725                 for (j = 0; j < max_state; j++)
1726                         len += sprintf(buf + len, "%10u",
1727                                 df->stats.trans_table[(i * max_state) + j]);
1728
1729                 len += sprintf(buf + len, "%10llu\n", (u64)
1730                         jiffies64_to_msecs(df->stats.time_in_state[i]));
1731         }
1732
1733         len += sprintf(buf + len, "Total transition : %u\n",
1734                                         df->stats.total_trans);
1735         return len;
1736 }
1737
1738 static ssize_t trans_stat_store(struct device *dev,
1739                                 struct device_attribute *attr,
1740                                 const char *buf, size_t count)
1741 {
1742         struct devfreq *df = to_devfreq(dev);
1743         int err, value;
1744
1745         if (!df->profile)
1746                 return -EINVAL;
1747
1748         if (df->max_state == 0)
1749                 return count;
1750
1751         err = kstrtoint(buf, 10, &value);
1752         if (err || value != 0)
1753                 return -EINVAL;
1754
1755         mutex_lock(&df->lock);
1756         memset(df->stats.time_in_state, 0, (df->max_state *
1757                                         sizeof(*df->stats.time_in_state)));
1758         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1759                                         df->max_state,
1760                                         df->max_state));
1761         df->stats.total_trans = 0;
1762         df->stats.last_update = get_jiffies_64();
1763         mutex_unlock(&df->lock);
1764
1765         return count;
1766 }
1767 static DEVICE_ATTR_RW(trans_stat);
1768
1769 static struct attribute *devfreq_attrs[] = {
1770         &dev_attr_name.attr,
1771         &dev_attr_governor.attr,
1772         &dev_attr_available_governors.attr,
1773         &dev_attr_cur_freq.attr,
1774         &dev_attr_available_frequencies.attr,
1775         &dev_attr_target_freq.attr,
1776         &dev_attr_min_freq.attr,
1777         &dev_attr_max_freq.attr,
1778         &dev_attr_trans_stat.attr,
1779         NULL,
1780 };
1781 ATTRIBUTE_GROUPS(devfreq);
1782
1783 static ssize_t polling_interval_show(struct device *dev,
1784                                      struct device_attribute *attr, char *buf)
1785 {
1786         struct devfreq *df = to_devfreq(dev);
1787
1788         if (!df->profile)
1789                 return -EINVAL;
1790
1791         return sprintf(buf, "%d\n", df->profile->polling_ms);
1792 }
1793
1794 static ssize_t polling_interval_store(struct device *dev,
1795                                       struct device_attribute *attr,
1796                                       const char *buf, size_t count)
1797 {
1798         struct devfreq *df = to_devfreq(dev);
1799         unsigned int value;
1800         int ret;
1801
1802         if (!df->governor)
1803                 return -EINVAL;
1804
1805         ret = sscanf(buf, "%u", &value);
1806         if (ret != 1)
1807                 return -EINVAL;
1808
1809         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1810         ret = count;
1811
1812         return ret;
1813 }
1814 static DEVICE_ATTR_RW(polling_interval);
1815
1816 static ssize_t timer_show(struct device *dev,
1817                              struct device_attribute *attr, char *buf)
1818 {
1819         struct devfreq *df = to_devfreq(dev);
1820
1821         if (!df->profile)
1822                 return -EINVAL;
1823
1824         return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
1825 }
1826
1827 static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1828                               const char *buf, size_t count)
1829 {
1830         struct devfreq *df = to_devfreq(dev);
1831         char str_timer[DEVFREQ_NAME_LEN + 1];
1832         int timer = -1;
1833         int ret = 0, i;
1834
1835         if (!df->governor || !df->profile)
1836                 return -EINVAL;
1837
1838         ret = sscanf(buf, "%16s", str_timer);
1839         if (ret != 1)
1840                 return -EINVAL;
1841
1842         for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1843                 if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1844                         timer = i;
1845                         break;
1846                 }
1847         }
1848
1849         if (timer < 0) {
1850                 ret = -EINVAL;
1851                 goto out;
1852         }
1853
1854         if (df->profile->timer == timer) {
1855                 ret = 0;
1856                 goto out;
1857         }
1858
1859         mutex_lock(&df->lock);
1860         df->profile->timer = timer;
1861         mutex_unlock(&df->lock);
1862
1863         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1864         if (ret) {
1865                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1866                          __func__, df->governor->name, ret);
1867                 goto out;
1868         }
1869
1870         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1871         if (ret)
1872                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1873                          __func__, df->governor->name, ret);
1874 out:
1875         return ret ? ret : count;
1876 }
1877 static DEVICE_ATTR_RW(timer);
1878
1879 #define CREATE_SYSFS_FILE(df, name)                                     \
1880 {                                                                       \
1881         int ret;                                                        \
1882         ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);  \
1883         if (ret < 0) {                                                  \
1884                 dev_warn(&df->dev,                                      \
1885                         "Unable to create attr(%s)\n", "##name");       \
1886         }                                                               \
1887 }                                                                       \
1888
1889 /* Create the specific sysfs files which depend on each governor. */
1890 static void create_sysfs_files(struct devfreq *devfreq,
1891                                 const struct devfreq_governor *gov)
1892 {
1893         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1894                 CREATE_SYSFS_FILE(devfreq, polling_interval);
1895         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1896                 CREATE_SYSFS_FILE(devfreq, timer);
1897 }
1898
1899 /* Remove the specific sysfs files which depend on each governor. */
1900 static void remove_sysfs_files(struct devfreq *devfreq,
1901                                 const struct devfreq_governor *gov)
1902 {
1903         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1904                 sysfs_remove_file(&devfreq->dev.kobj,
1905                                 &dev_attr_polling_interval.attr);
1906         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1907                 sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
1908 }
1909
1910 /**
1911  * devfreq_summary_show() - Show the summary of the devfreq devices
1912  * @s:          seq_file instance to show the summary of devfreq devices
1913  * @data:       not used
1914  *
1915  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1916  * It helps that user can know the detailed information of the devfreq devices.
1917  *
1918  * Return 0 always because it shows the information without any data change.
1919  */
1920 static int devfreq_summary_show(struct seq_file *s, void *data)
1921 {
1922         struct devfreq *devfreq;
1923         struct devfreq *p_devfreq = NULL;
1924         unsigned long cur_freq, min_freq, max_freq;
1925         unsigned int polling_ms;
1926         unsigned int timer;
1927
1928         seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1929                         "dev",
1930                         "parent_dev",
1931                         "governor",
1932                         "timer",
1933                         "polling_ms",
1934                         "cur_freq_Hz",
1935                         "min_freq_Hz",
1936                         "max_freq_Hz");
1937         seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1938                         "------------------------------",
1939                         "------------------------------",
1940                         "---------------",
1941                         "----------",
1942                         "----------",
1943                         "------------",
1944                         "------------",
1945                         "------------");
1946
1947         mutex_lock(&devfreq_list_lock);
1948
1949         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1950 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1951                 if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
1952                                                         DEVFREQ_NAME_LEN)) {
1953                         struct devfreq_passive_data *data = devfreq->data;
1954
1955                         if (data)
1956                                 p_devfreq = data->parent;
1957                 } else {
1958                         p_devfreq = NULL;
1959                 }
1960 #endif
1961
1962                 mutex_lock(&devfreq->lock);
1963                 cur_freq = devfreq->previous_freq;
1964                 devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
1965                 timer = devfreq->profile->timer;
1966
1967                 if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
1968                         polling_ms = devfreq->profile->polling_ms;
1969                 else
1970                         polling_ms = 0;
1971                 mutex_unlock(&devfreq->lock);
1972
1973                 seq_printf(s,
1974                         "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
1975                         dev_name(&devfreq->dev),
1976                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1977                         devfreq->governor->name,
1978                         polling_ms ? timer_name[timer] : "null",
1979                         polling_ms,
1980                         cur_freq,
1981                         min_freq,
1982                         max_freq);
1983         }
1984
1985         mutex_unlock(&devfreq_list_lock);
1986
1987         return 0;
1988 }
1989 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1990
1991 static int __init devfreq_init(void)
1992 {
1993         devfreq_class = class_create("devfreq");
1994         if (IS_ERR(devfreq_class)) {
1995                 pr_err("%s: couldn't create class\n", __FILE__);
1996                 return PTR_ERR(devfreq_class);
1997         }
1998
1999         devfreq_wq = create_freezable_workqueue("devfreq_wq");
2000         if (!devfreq_wq) {
2001                 class_destroy(devfreq_class);
2002                 pr_err("%s: couldn't create workqueue\n", __FILE__);
2003                 return -ENOMEM;
2004         }
2005         devfreq_class->dev_groups = devfreq_groups;
2006
2007         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
2008         debugfs_create_file("devfreq_summary", 0444,
2009                                 devfreq_debugfs, NULL,
2010                                 &devfreq_summary_fops);
2011
2012         return 0;
2013 }
2014 subsys_initcall(devfreq_init);
2015
2016 /*
2017  * The following are helper functions for devfreq user device drivers with
2018  * OPP framework.
2019  */
2020
2021 /**
2022  * devfreq_recommended_opp() - Helper function to get proper OPP for the
2023  *                           freq value given to target callback.
2024  * @dev:        The devfreq user device. (parent of devfreq)
2025  * @freq:       The frequency given to target function
2026  * @flags:      Flags handed from devfreq framework.
2027  *
2028  * The callers are required to call dev_pm_opp_put() for the returned OPP after
2029  * use.
2030  */
2031 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
2032                                            unsigned long *freq,
2033                                            u32 flags)
2034 {
2035         struct dev_pm_opp *opp;
2036
2037         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
2038                 /* The freq is an upper bound. opp should be lower */
2039                 opp = dev_pm_opp_find_freq_floor(dev, freq);
2040
2041                 /* If not available, use the closest opp */
2042                 if (opp == ERR_PTR(-ERANGE))
2043                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
2044         } else {
2045                 /* The freq is an lower bound. opp should be higher */
2046                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
2047
2048                 /* If not available, use the closest opp */
2049                 if (opp == ERR_PTR(-ERANGE))
2050                         opp = dev_pm_opp_find_freq_floor(dev, freq);
2051         }
2052
2053         return opp;
2054 }
2055 EXPORT_SYMBOL(devfreq_recommended_opp);
2056
2057 /**
2058  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
2059  *                                   for any changes in the OPP availability
2060  *                                   changes
2061  * @dev:        The devfreq user device. (parent of devfreq)
2062  * @devfreq:    The devfreq object.
2063  */
2064 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
2065 {
2066         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
2067 }
2068 EXPORT_SYMBOL(devfreq_register_opp_notifier);
2069
2070 /**
2071  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
2072  *                                     notified for any changes in the OPP
2073  *                                     availability changes anymore.
2074  * @dev:        The devfreq user device. (parent of devfreq)
2075  * @devfreq:    The devfreq object.
2076  *
2077  * At exit() callback of devfreq_dev_profile, this must be included if
2078  * devfreq_recommended_opp is used.
2079  */
2080 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
2081 {
2082         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
2083 }
2084 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
2085
2086 static void devm_devfreq_opp_release(struct device *dev, void *res)
2087 {
2088         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
2089 }
2090
2091 /**
2092  * devm_devfreq_register_opp_notifier() - Resource-managed
2093  *                                        devfreq_register_opp_notifier()
2094  * @dev:        The devfreq user device. (parent of devfreq)
2095  * @devfreq:    The devfreq object.
2096  */
2097 int devm_devfreq_register_opp_notifier(struct device *dev,
2098                                        struct devfreq *devfreq)
2099 {
2100         struct devfreq **ptr;
2101         int ret;
2102
2103         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
2104         if (!ptr)
2105                 return -ENOMEM;
2106
2107         ret = devfreq_register_opp_notifier(dev, devfreq);
2108         if (ret) {
2109                 devres_free(ptr);
2110                 return ret;
2111         }
2112
2113         *ptr = devfreq;
2114         devres_add(dev, ptr);
2115
2116         return 0;
2117 }
2118 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2119
2120 /**
2121  * devm_devfreq_unregister_opp_notifier() - Resource-managed
2122  *                                          devfreq_unregister_opp_notifier()
2123  * @dev:        The devfreq user device. (parent of devfreq)
2124  * @devfreq:    The devfreq object.
2125  */
2126 void devm_devfreq_unregister_opp_notifier(struct device *dev,
2127                                          struct devfreq *devfreq)
2128 {
2129         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2130                                devm_devfreq_dev_match, devfreq));
2131 }
2132 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2133
2134 /**
2135  * devfreq_register_notifier() - Register a driver with devfreq
2136  * @devfreq:    The devfreq object.
2137  * @nb:         The notifier block to register.
2138  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2139  */
2140 int devfreq_register_notifier(struct devfreq *devfreq,
2141                               struct notifier_block *nb,
2142                               unsigned int list)
2143 {
2144         int ret = 0;
2145
2146         if (!devfreq)
2147                 return -EINVAL;
2148
2149         switch (list) {
2150         case DEVFREQ_TRANSITION_NOTIFIER:
2151                 ret = srcu_notifier_chain_register(
2152                                 &devfreq->transition_notifier_list, nb);
2153                 break;
2154         default:
2155                 ret = -EINVAL;
2156         }
2157
2158         return ret;
2159 }
2160 EXPORT_SYMBOL(devfreq_register_notifier);
2161
2162 /*
2163  * devfreq_unregister_notifier() - Unregister a driver with devfreq
2164  * @devfreq:    The devfreq object.
2165  * @nb:         The notifier block to be unregistered.
2166  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2167  */
2168 int devfreq_unregister_notifier(struct devfreq *devfreq,
2169                                 struct notifier_block *nb,
2170                                 unsigned int list)
2171 {
2172         int ret = 0;
2173
2174         if (!devfreq)
2175                 return -EINVAL;
2176
2177         switch (list) {
2178         case DEVFREQ_TRANSITION_NOTIFIER:
2179                 ret = srcu_notifier_chain_unregister(
2180                                 &devfreq->transition_notifier_list, nb);
2181                 break;
2182         default:
2183                 ret = -EINVAL;
2184         }
2185
2186         return ret;
2187 }
2188 EXPORT_SYMBOL(devfreq_unregister_notifier);
2189
2190 struct devfreq_notifier_devres {
2191         struct devfreq *devfreq;
2192         struct notifier_block *nb;
2193         unsigned int list;
2194 };
2195
2196 static void devm_devfreq_notifier_release(struct device *dev, void *res)
2197 {
2198         struct devfreq_notifier_devres *this = res;
2199
2200         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2201 }
2202
2203 /**
2204  * devm_devfreq_register_notifier()
2205  *      - Resource-managed devfreq_register_notifier()
2206  * @dev:        The devfreq user device. (parent of devfreq)
2207  * @devfreq:    The devfreq object.
2208  * @nb:         The notifier block to be unregistered.
2209  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2210  */
2211 int devm_devfreq_register_notifier(struct device *dev,
2212                                 struct devfreq *devfreq,
2213                                 struct notifier_block *nb,
2214                                 unsigned int list)
2215 {
2216         struct devfreq_notifier_devres *ptr;
2217         int ret;
2218
2219         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2220                                 GFP_KERNEL);
2221         if (!ptr)
2222                 return -ENOMEM;
2223
2224         ret = devfreq_register_notifier(devfreq, nb, list);
2225         if (ret) {
2226                 devres_free(ptr);
2227                 return ret;
2228         }
2229
2230         ptr->devfreq = devfreq;
2231         ptr->nb = nb;
2232         ptr->list = list;
2233         devres_add(dev, ptr);
2234
2235         return 0;
2236 }
2237 EXPORT_SYMBOL(devm_devfreq_register_notifier);
2238
2239 /**
2240  * devm_devfreq_unregister_notifier()
2241  *      - Resource-managed devfreq_unregister_notifier()
2242  * @dev:        The devfreq user device. (parent of devfreq)
2243  * @devfreq:    The devfreq object.
2244  * @nb:         The notifier block to be unregistered.
2245  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2246  */
2247 void devm_devfreq_unregister_notifier(struct device *dev,
2248                                       struct devfreq *devfreq,
2249                                       struct notifier_block *nb,
2250                                       unsigned int list)
2251 {
2252         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2253                                devm_devfreq_dev_match, devfreq));
2254 }
2255 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);