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