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 "governor.h"
  31
  32 #define CREATE_TRACE_POINTS
  33 #include <trace/events/devfreq.h>
  34
  35 #define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
  36 #define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
  37 #define HZ_PER_KHZ      1000
  38
  39 static struct class *devfreq_class;
  40 static struct dentry *devfreq_debugfs;
  41
  42 /*
  43  * devfreq core provides delayed work based load monitoring helper
  44  * functions. Governors can use these or can implement their own
  45  * monitoring mechanism.
  46  */
  47 static struct workqueue_struct *devfreq_wq;
  48
  49 /* The list of all device-devfreq governors */
  50 static LIST_HEAD(devfreq_governor_list);
  51 /* The list of all device-devfreq */
  52 static LIST_HEAD(devfreq_list);
  53 static DEFINE_MUTEX(devfreq_list_lock);
  54
  55 static const char timer_name[][DEVFREQ_NAME_LEN] = {
  56         [DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
  57         [DEVFREQ_TIMER_DELAYED] = { "delayed" },
  58 };
  59
  60 /**
  61  * find_device_devfreq() - find devfreq struct using device pointer
  62  * @dev:        device pointer used to lookup device devfreq.
  63  *
  64  * Search the list of device devfreqs and return the matched device's
  65  * devfreq info. devfreq_list_lock should be held by the caller.
  66  */
  67 static struct devfreq *find_device_devfreq(struct device *dev)
  68 {
  69         struct devfreq *tmp_devfreq;
  70
  71         lockdep_assert_held(&devfreq_list_lock);
  72
  73         if (IS_ERR_OR_NULL(dev)) {
  74                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  75                 return ERR_PTR(-EINVAL);
  76         }
  77
  78         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  79                 if (tmp_devfreq->dev.parent == dev)
  80                         return tmp_devfreq;
  81         }
  82
  83         return ERR_PTR(-ENODEV);
  84 }
  85
  86 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  87 {
  88         struct dev_pm_opp *opp;
  89         unsigned long min_freq = 0;
  90
  91         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  92         if (IS_ERR(opp))
  93                 min_freq = 0;
  94         else
  95                 dev_pm_opp_put(opp);
  96
  97         return min_freq;
  98 }
  99
 100 static unsigned long find_available_max_freq(struct devfreq *devfreq)
 101 {
 102         struct dev_pm_opp *opp;
 103         unsigned long max_freq = ULONG_MAX;
 104
 105         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
 106         if (IS_ERR(opp))
 107                 max_freq = 0;
 108         else
 109                 dev_pm_opp_put(opp);
 110
 111         return max_freq;
 112 }
 113
 114 /**
 115  * get_freq_range() - Get the current freq range
 116  * @devfreq:    the devfreq instance
 117  * @min_freq:   the min frequency
 118  * @max_freq:   the max frequency
 119  *
 120  * This takes into consideration all constraints.
 121  */
 122 static void get_freq_range(struct devfreq *devfreq,
 123                            unsigned long *min_freq,
 124                            unsigned long *max_freq)
 125 {
 126         unsigned long *freq_table = devfreq->profile->freq_table;
 127         s32 qos_min_freq, qos_max_freq;
 128
 129         lockdep_assert_held(&devfreq->lock);
 130
 131         /*
 132          * Initialize minimum/maximum frequency from freq table.
 133          * The devfreq drivers can initialize this in either ascending or
 134          * descending order and devfreq core supports both.
 135          */
 136         if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
 137                 *min_freq = freq_table[0];
 138                 *max_freq = freq_table[devfreq->profile->max_state - 1];
 139         } else {
 140                 *min_freq = freq_table[devfreq->profile->max_state - 1];
 141                 *max_freq = freq_table[0];
 142         }
 143
 144         /* Apply constraints from PM QoS */
 145         qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 146                                              DEV_PM_QOS_MIN_FREQUENCY);
 147         qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 148                                              DEV_PM_QOS_MAX_FREQUENCY);
 149         *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 150         if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 151                 *max_freq = min(*max_freq,
 152                                 (unsigned long)HZ_PER_KHZ * qos_max_freq);
 153
 154         /* Apply constraints from OPP interface */
 155         *min_freq = max(*min_freq, devfreq->scaling_min_freq);
 156         *max_freq = min(*max_freq, devfreq->scaling_max_freq);
 157
 158         if (*min_freq > *max_freq)
 159                 *min_freq = *max_freq;
 160 }
 161
 162 /**
 163  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 164  * @devfreq:    the devfreq instance
 165  * @freq:       the target frequency
 166  */
 167 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 168 {
 169         int lev;
 170
 171         for (lev = 0; lev < devfreq->profile->max_state; lev++)
 172                 if (freq == devfreq->profile->freq_table[lev])
 173                         return lev;
 174
 175         return -EINVAL;
 176 }
 177
 178 static int set_freq_table(struct devfreq *devfreq)
 179 {
 180         struct devfreq_dev_profile *profile = devfreq->profile;
 181         struct dev_pm_opp *opp;
 182         unsigned long freq;
 183         int i, count;
 184
 185         /* Initialize the freq_table from OPP table */
 186         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 187         if (count <= 0)
 188                 return -EINVAL;
 189
 190         profile->max_state = count;
 191         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 192                                         profile->max_state,
 193                                         sizeof(*profile->freq_table),
 194                                         GFP_KERNEL);
 195         if (!profile->freq_table) {
 196                 profile->max_state = 0;
 197                 return -ENOMEM;
 198         }
 199
 200         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 201                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 202                 if (IS_ERR(opp)) {
 203                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 204                         profile->max_state = 0;
 205                         return PTR_ERR(opp);
 206                 }
 207                 dev_pm_opp_put(opp);
 208                 profile->freq_table[i] = freq;
 209         }
 210
 211         return 0;
 212 }
 213
 214 /**
 215  * devfreq_update_status() - Update statistics of devfreq behavior
 216  * @devfreq:    the devfreq instance
 217  * @freq:       the update target frequency
 218  */
 219 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 220 {
 221         int lev, prev_lev, ret = 0;
 222         u64 cur_time;
 223
 224         lockdep_assert_held(&devfreq->lock);
 225         cur_time = get_jiffies_64();
 226
 227         /* Immediately exit if previous_freq is not initialized yet. */
 228         if (!devfreq->previous_freq)
 229                 goto out;
 230
 231         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 232         if (prev_lev < 0) {
 233                 ret = prev_lev;
 234                 goto out;
 235         }
 236
 237         devfreq->stats.time_in_state[prev_lev] +=
 238                         cur_time - devfreq->stats.last_update;
 239
 240         lev = devfreq_get_freq_level(devfreq, freq);
 241         if (lev < 0) {
 242                 ret = lev;
 243                 goto out;
 244         }
 245
 246         if (lev != prev_lev) {
 247                 devfreq->stats.trans_table[
 248                         (prev_lev * devfreq->profile->max_state) + lev]++;
 249                 devfreq->stats.total_trans++;
 250         }
 251
 252 out:
 253         devfreq->stats.last_update = cur_time;
 254         return ret;
 255 }
 256 EXPORT_SYMBOL(devfreq_update_status);
 257
 258 /**
 259  * find_devfreq_governor() - find devfreq governor from name
 260  * @name:       name of the governor
 261  *
 262  * Search the list of devfreq governors and return the matched
 263  * governor's pointer. devfreq_list_lock should be held by the caller.
 264  */
 265 static struct devfreq_governor *find_devfreq_governor(const char *name)
 266 {
 267         struct devfreq_governor *tmp_governor;
 268
 269         lockdep_assert_held(&devfreq_list_lock);
 270
 271         if (IS_ERR_OR_NULL(name)) {
 272                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 273                 return ERR_PTR(-EINVAL);
 274         }
 275
 276         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 277                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 278                         return tmp_governor;
 279         }
 280
 281         return ERR_PTR(-ENODEV);
 282 }
 283
 284 /**
 285  * try_then_request_governor() - Try to find the governor and request the
 286  *                               module if is not found.
 287  * @name:       name of the governor
 288  *
 289  * Search the list of devfreq governors and request the module and try again
 290  * if is not found. This can happen when both drivers (the governor driver
 291  * and the driver that call devfreq_add_device) are built as modules.
 292  * devfreq_list_lock should be held by the caller. Returns the matched
 293  * governor's pointer or an error pointer.
 294  */
 295 static struct devfreq_governor *try_then_request_governor(const char *name)
 296 {
 297         struct devfreq_governor *governor;
 298         int err = 0;
 299
 300         lockdep_assert_held(&devfreq_list_lock);
 301
 302         if (IS_ERR_OR_NULL(name)) {
 303                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 304                 return ERR_PTR(-EINVAL);
 305         }
 306
 307         governor = find_devfreq_governor(name);
 308         if (IS_ERR(governor)) {
 309                 mutex_unlock(&devfreq_list_lock);
 310
 311                 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 312                              DEVFREQ_NAME_LEN))
 313                         err = request_module("governor_%s", "simpleondemand");
 314                 else
 315                         err = request_module("governor_%s", name);
 316                 /* Restore previous state before return */
 317                 mutex_lock(&devfreq_list_lock);
 318                 if (err)
 319                         return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 320
 321                 governor = find_devfreq_governor(name);
 322         }
 323
 324         return governor;
 325 }
 326
 327 static int devfreq_notify_transition(struct devfreq *devfreq,
 328                 struct devfreq_freqs *freqs, unsigned int state)
 329 {
 330         if (!devfreq)
 331                 return -EINVAL;
 332
 333         switch (state) {
 334         case DEVFREQ_PRECHANGE:
 335                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 336                                 DEVFREQ_PRECHANGE, freqs);
 337                 break;
 338
 339         case DEVFREQ_POSTCHANGE:
 340                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 341                                 DEVFREQ_POSTCHANGE, freqs);
 342                 break;
 343         default:
 344                 return -EINVAL;
 345         }
 346
 347         return 0;
 348 }
 349
 350 static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 351                               u32 flags)
 352 {
 353         struct devfreq_freqs freqs;
 354         unsigned long cur_freq;
 355         int err = 0;
 356
 357         if (devfreq->profile->get_cur_freq)
 358                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 359         else
 360                 cur_freq = devfreq->previous_freq;
 361
 362         freqs.old = cur_freq;
 363         freqs.new = new_freq;
 364         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 365
 366         err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 367         if (err) {
 368                 freqs.new = cur_freq;
 369                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 370                 return err;
 371         }
 372
 373         /*
 374          * Print devfreq_frequency trace information between DEVFREQ_PRECHANGE
 375          * and DEVFREQ_POSTCHANGE because for showing the correct frequency
 376          * change order of between devfreq device and passive devfreq device.
 377          */
 378         if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
 379                 trace_devfreq_frequency(devfreq, new_freq, cur_freq);
 380
 381         freqs.new = new_freq;
 382         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 383
 384         if (devfreq_update_status(devfreq, new_freq))
 385                 dev_err(&devfreq->dev,
 386                         "Couldn't update frequency transition information.\n");
 387
 388         devfreq->previous_freq = new_freq;
 389
 390         if (devfreq->suspend_freq)
 391                 devfreq->resume_freq = new_freq;
 392
 393         return err;
 394 }
 395
 396 /**
 397  * devfreq_update_target() - Reevaluate the device and configure frequency
 398  *                         on the final stage.
 399  * @devfreq:    the devfreq instance.
 400  * @freq:       the new frequency of parent device. This argument
 401  *              is only used for devfreq device using passive governor.
 402  *
 403  * Note: Lock devfreq->lock before calling devfreq_update_target. This function
 404  *       should be only used by both update_devfreq() and devfreq governors.
 405  */
 406 int devfreq_update_target(struct devfreq *devfreq, unsigned long freq)
 407 {
 408         unsigned long min_freq, max_freq;
 409         int err = 0;
 410         u32 flags = 0;
 411
 412         lockdep_assert_held(&devfreq->lock);
 413
 414         if (!devfreq->governor)
 415                 return -EINVAL;
 416
 417         /* Reevaluate the proper frequency */
 418         err = devfreq->governor->get_target_freq(devfreq, &freq);
 419         if (err)
 420                 return err;
 421         get_freq_range(devfreq, &min_freq, &max_freq);
 422
 423         if (freq < min_freq) {
 424                 freq = min_freq;
 425                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 426         }
 427         if (freq > max_freq) {
 428                 freq = max_freq;
 429                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 430         }
 431
 432         return devfreq_set_target(devfreq, freq, flags);
 433 }
 434 EXPORT_SYMBOL(devfreq_update_target);
 435
 436 /* Load monitoring helper functions for governors use */
 437
 438 /**
 439  * update_devfreq() - Reevaluate the device and configure frequency.
 440  * @devfreq:    the devfreq instance.
 441  *
 442  * Note: Lock devfreq->lock before calling update_devfreq
 443  *       This function is exported for governors.
 444  */
 445 int update_devfreq(struct devfreq *devfreq)
 446 {
 447         return devfreq_update_target(devfreq, 0L);
 448 }
 449 EXPORT_SYMBOL(update_devfreq);
 450
 451 /**
 452  * devfreq_monitor() - Periodically poll devfreq objects.
 453  * @work:       the work struct used to run devfreq_monitor periodically.
 454  *
 455  */
 456 static void devfreq_monitor(struct work_struct *work)
 457 {
 458         int err;
 459         struct devfreq *devfreq = container_of(work,
 460                                         struct devfreq, work.work);
 461
 462         mutex_lock(&devfreq->lock);
 463         err = update_devfreq(devfreq);
 464         if (err)
 465                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 466
 467         queue_delayed_work(devfreq_wq, &devfreq->work,
 468                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 469         mutex_unlock(&devfreq->lock);
 470
 471         trace_devfreq_monitor(devfreq);
 472 }
 473
 474 /**
 475  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 476  * @devfreq:    the devfreq instance.
 477  *
 478  * Helper function for starting devfreq device load monitoring. By
 479  * default delayed work based monitoring is supported. Function
 480  * to be called from governor in response to DEVFREQ_GOV_START
 481  * event when device is added to devfreq framework.
 482  */
 483 void devfreq_monitor_start(struct devfreq *devfreq)
 484 {
 485         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 486                 return;
 487
 488         switch (devfreq->profile->timer) {
 489         case DEVFREQ_TIMER_DEFERRABLE:
 490                 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 491                 break;
 492         case DEVFREQ_TIMER_DELAYED:
 493                 INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
 494                 break;
 495         default:
 496                 return;
 497         }
 498
 499         if (devfreq->profile->polling_ms)
 500                 queue_delayed_work(devfreq_wq, &devfreq->work,
 501                         msecs_to_jiffies(devfreq->profile->polling_ms));
 502 }
 503 EXPORT_SYMBOL(devfreq_monitor_start);
 504
 505 /**
 506  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 507  * @devfreq:    the devfreq instance.
 508  *
 509  * Helper function to stop devfreq device load monitoring. Function
 510  * to be called from governor in response to DEVFREQ_GOV_STOP
 511  * event when device is removed from devfreq framework.
 512  */
 513 void devfreq_monitor_stop(struct devfreq *devfreq)
 514 {
 515         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 516                 return;
 517
 518         cancel_delayed_work_sync(&devfreq->work);
 519 }
 520 EXPORT_SYMBOL(devfreq_monitor_stop);
 521
 522 /**
 523  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 524  * @devfreq:    the devfreq instance.
 525  *
 526  * Helper function to suspend devfreq device load monitoring. Function
 527  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 528  * event or when polling interval is set to zero.
 529  *
 530  * Note: Though this function is same as devfreq_monitor_stop(),
 531  * intentionally kept separate to provide hooks for collecting
 532  * transition statistics.
 533  */
 534 void devfreq_monitor_suspend(struct devfreq *devfreq)
 535 {
 536         mutex_lock(&devfreq->lock);
 537         if (devfreq->stop_polling) {
 538                 mutex_unlock(&devfreq->lock);
 539                 return;
 540         }
 541
 542         devfreq_update_status(devfreq, devfreq->previous_freq);
 543         devfreq->stop_polling = true;
 544         mutex_unlock(&devfreq->lock);
 545
 546         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 547                 return;
 548
 549         cancel_delayed_work_sync(&devfreq->work);
 550 }
 551 EXPORT_SYMBOL(devfreq_monitor_suspend);
 552
 553 /**
 554  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 555  * @devfreq:    the devfreq instance.
 556  *
 557  * Helper function to resume devfreq device load monitoring. Function
 558  * to be called from governor in response to DEVFREQ_GOV_RESUME
 559  * event or when polling interval is set to non-zero.
 560  */
 561 void devfreq_monitor_resume(struct devfreq *devfreq)
 562 {
 563         unsigned long freq;
 564
 565         mutex_lock(&devfreq->lock);
 566
 567         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 568                 goto out_update;
 569
 570         if (!devfreq->stop_polling)
 571                 goto out;
 572
 573         if (!delayed_work_pending(&devfreq->work) &&
 574                         devfreq->profile->polling_ms)
 575                 queue_delayed_work(devfreq_wq, &devfreq->work,
 576                         msecs_to_jiffies(devfreq->profile->polling_ms));
 577
 578 out_update:
 579         devfreq->stats.last_update = get_jiffies_64();
 580         devfreq->stop_polling = false;
 581
 582         if (devfreq->profile->get_cur_freq &&
 583                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 584                 devfreq->previous_freq = freq;
 585
 586 out:
 587         mutex_unlock(&devfreq->lock);
 588 }
 589 EXPORT_SYMBOL(devfreq_monitor_resume);
 590
 591 /**
 592  * devfreq_update_interval() - Update device devfreq monitoring interval
 593  * @devfreq:    the devfreq instance.
 594  * @delay:      new polling interval to be set.
 595  *
 596  * Helper function to set new load monitoring polling interval. Function
 597  * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 598  */
 599 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 600 {
 601         unsigned int cur_delay = devfreq->profile->polling_ms;
 602         unsigned int new_delay = *delay;
 603
 604         mutex_lock(&devfreq->lock);
 605         devfreq->profile->polling_ms = new_delay;
 606
 607         if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 608                 goto out;
 609
 610         if (devfreq->stop_polling)
 611                 goto out;
 612
 613         /* if new delay is zero, stop polling */
 614         if (!new_delay) {
 615                 mutex_unlock(&devfreq->lock);
 616                 cancel_delayed_work_sync(&devfreq->work);
 617                 return;
 618         }
 619
 620         /* if current delay is zero, start polling with new delay */
 621         if (!cur_delay) {
 622                 queue_delayed_work(devfreq_wq, &devfreq->work,
 623                         msecs_to_jiffies(devfreq->profile->polling_ms));
 624                 goto out;
 625         }
 626
 627         /* if current delay is greater than new delay, restart polling */
 628         if (cur_delay > new_delay) {
 629                 mutex_unlock(&devfreq->lock);
 630                 cancel_delayed_work_sync(&devfreq->work);
 631                 mutex_lock(&devfreq->lock);
 632                 if (!devfreq->stop_polling)
 633                         queue_delayed_work(devfreq_wq, &devfreq->work,
 634                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 635         }
 636 out:
 637         mutex_unlock(&devfreq->lock);
 638 }
 639 EXPORT_SYMBOL(devfreq_update_interval);
 640
 641 /**
 642  * devfreq_notifier_call() - Notify that the device frequency requirements
 643  *                           has been changed out of devfreq framework.
 644  * @nb:         the notifier_block (supposed to be devfreq->nb)
 645  * @type:       not used
 646  * @devp:       not used
 647  *
 648  * Called by a notifier that uses devfreq->nb.
 649  */
 650 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 651                                  void *devp)
 652 {
 653         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 654         int err = -EINVAL;
 655
 656         mutex_lock(&devfreq->lock);
 657
 658         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 659         if (!devfreq->scaling_min_freq)
 660                 goto out;
 661
 662         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 663         if (!devfreq->scaling_max_freq) {
 664                 devfreq->scaling_max_freq = ULONG_MAX;
 665                 goto out;
 666         }
 667
 668         err = update_devfreq(devfreq);
 669
 670 out:
 671         mutex_unlock(&devfreq->lock);
 672         if (err)
 673                 dev_err(devfreq->dev.parent,
 674                         "failed to update frequency from OPP notifier (%d)\n",
 675                         err);
 676
 677         return NOTIFY_OK;
 678 }
 679
 680 /**
 681  * qos_notifier_call() - Common handler for QoS constraints.
 682  * @devfreq:    the devfreq instance.
 683  */
 684 static int qos_notifier_call(struct devfreq *devfreq)
 685 {
 686         int err;
 687
 688         mutex_lock(&devfreq->lock);
 689         err = update_devfreq(devfreq);
 690         mutex_unlock(&devfreq->lock);
 691         if (err)
 692                 dev_err(devfreq->dev.parent,
 693                         "failed to update frequency from PM QoS (%d)\n",
 694                         err);
 695
 696         return NOTIFY_OK;
 697 }
 698
 699 /**
 700  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 701  * @nb:         Should be devfreq->nb_min
 702  */
 703 static int qos_min_notifier_call(struct notifier_block *nb,
 704                                          unsigned long val, void *ptr)
 705 {
 706         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 707 }
 708
 709 /**
 710  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 711  * @nb:         Should be devfreq->nb_max
 712  */
 713 static int qos_max_notifier_call(struct notifier_block *nb,
 714                                          unsigned long val, void *ptr)
 715 {
 716         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 717 }
 718
 719 /**
 720  * devfreq_dev_release() - Callback for struct device to release the device.
 721  * @dev:        the devfreq device
 722  *
 723  * Remove devfreq from the list and release its resources.
 724  */
 725 static void devfreq_dev_release(struct device *dev)
 726 {
 727         struct devfreq *devfreq = to_devfreq(dev);
 728         int err;
 729
 730         mutex_lock(&devfreq_list_lock);
 731         list_del(&devfreq->node);
 732         mutex_unlock(&devfreq_list_lock);
 733
 734         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 735                                          DEV_PM_QOS_MAX_FREQUENCY);
 736         if (err && err != -ENOENT)
 737                 dev_warn(dev->parent,
 738                         "Failed to remove max_freq notifier: %d\n", err);
 739         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 740                                          DEV_PM_QOS_MIN_FREQUENCY);
 741         if (err && err != -ENOENT)
 742                 dev_warn(dev->parent,
 743                         "Failed to remove min_freq notifier: %d\n", err);
 744
 745         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 746                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 747                 if (err < 0)
 748                         dev_warn(dev->parent,
 749                                 "Failed to remove max_freq request: %d\n", err);
 750         }
 751         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 752                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 753                 if (err < 0)
 754                         dev_warn(dev->parent,
 755                                 "Failed to remove min_freq request: %d\n", err);
 756         }
 757
 758         if (devfreq->profile->exit)
 759                 devfreq->profile->exit(devfreq->dev.parent);
 760
 761         if (devfreq->opp_table)
 762                 dev_pm_opp_put_opp_table(devfreq->opp_table);
 763
 764         mutex_destroy(&devfreq->lock);
 765         kfree(devfreq);
 766 }
 767
 768 static void create_sysfs_files(struct devfreq *devfreq,
 769                                 const struct devfreq_governor *gov);
 770 static void remove_sysfs_files(struct devfreq *devfreq,
 771                                 const struct devfreq_governor *gov);
 772
 773 /**
 774  * devfreq_add_device() - Add devfreq feature to the device
 775  * @dev:        the device to add devfreq feature.
 776  * @profile:    device-specific profile to run devfreq.
 777  * @governor_name:      name of the policy to choose frequency.
 778  * @data:       private data for the governor. The devfreq framework does not
 779  *              touch this value.
 780  */
 781 struct devfreq *devfreq_add_device(struct device *dev,
 782                                    struct devfreq_dev_profile *profile,
 783                                    const char *governor_name,
 784                                    void *data)
 785 {
 786         struct devfreq *devfreq;
 787         struct devfreq_governor *governor;
 788         int err = 0;
 789
 790         if (!dev || !profile || !governor_name) {
 791                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 792                 return ERR_PTR(-EINVAL);
 793         }
 794
 795         mutex_lock(&devfreq_list_lock);
 796         devfreq = find_device_devfreq(dev);
 797         mutex_unlock(&devfreq_list_lock);
 798         if (!IS_ERR(devfreq)) {
 799                 dev_err(dev, "%s: devfreq device already exists!\n",
 800                         __func__);
 801                 err = -EINVAL;
 802                 goto err_out;
 803         }
 804
 805         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 806         if (!devfreq) {
 807                 err = -ENOMEM;
 808                 goto err_out;
 809         }
 810
 811         mutex_init(&devfreq->lock);
 812         mutex_lock(&devfreq->lock);
 813         devfreq->dev.parent = dev;
 814         devfreq->dev.class = devfreq_class;
 815         devfreq->dev.release = devfreq_dev_release;
 816         INIT_LIST_HEAD(&devfreq->node);
 817         devfreq->profile = profile;
 818         devfreq->previous_freq = profile->initial_freq;
 819         devfreq->last_status.current_frequency = profile->initial_freq;
 820         devfreq->data = data;
 821         devfreq->nb.notifier_call = devfreq_notifier_call;
 822
 823         if (devfreq->profile->timer < 0
 824                 || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 825                 mutex_unlock(&devfreq->lock);
 826                 goto err_dev;
 827         }
 828
 829         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 830                 mutex_unlock(&devfreq->lock);
 831                 err = set_freq_table(devfreq);
 832                 if (err < 0)
 833                         goto err_dev;
 834                 mutex_lock(&devfreq->lock);
 835         }
 836
 837         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 838         if (!devfreq->scaling_min_freq) {
 839                 mutex_unlock(&devfreq->lock);
 840                 err = -EINVAL;
 841                 goto err_dev;
 842         }
 843
 844         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 845         if (!devfreq->scaling_max_freq) {
 846                 mutex_unlock(&devfreq->lock);
 847                 err = -EINVAL;
 848                 goto err_dev;
 849         }
 850
 851         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 852         devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
 853         if (IS_ERR(devfreq->opp_table))
 854                 devfreq->opp_table = NULL;
 855
 856         atomic_set(&devfreq->suspend_count, 0);
 857
 858         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 859         err = device_register(&devfreq->dev);
 860         if (err) {
 861                 mutex_unlock(&devfreq->lock);
 862                 put_device(&devfreq->dev);
 863                 goto err_out;
 864         }
 865
 866         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 867                         array3_size(sizeof(unsigned int),
 868                                     devfreq->profile->max_state,
 869                                     devfreq->profile->max_state),
 870                         GFP_KERNEL);
 871         if (!devfreq->stats.trans_table) {
 872                 mutex_unlock(&devfreq->lock);
 873                 err = -ENOMEM;
 874                 goto err_devfreq;
 875         }
 876
 877         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 878                         devfreq->profile->max_state,
 879                         sizeof(*devfreq->stats.time_in_state),
 880                         GFP_KERNEL);
 881         if (!devfreq->stats.time_in_state) {
 882                 mutex_unlock(&devfreq->lock);
 883                 err = -ENOMEM;
 884                 goto err_devfreq;
 885         }
 886
 887         devfreq->stats.total_trans = 0;
 888         devfreq->stats.last_update = get_jiffies_64();
 889
 890         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 891
 892         mutex_unlock(&devfreq->lock);
 893
 894         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 895                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 896         if (err < 0)
 897                 goto err_devfreq;
 898         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 899                                      DEV_PM_QOS_MAX_FREQUENCY,
 900                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 901         if (err < 0)
 902                 goto err_devfreq;
 903
 904         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 905         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
 906                                       DEV_PM_QOS_MIN_FREQUENCY);
 907         if (err)
 908                 goto err_devfreq;
 909
 910         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 911         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
 912                                       DEV_PM_QOS_MAX_FREQUENCY);
 913         if (err)
 914                 goto err_devfreq;
 915
 916         mutex_lock(&devfreq_list_lock);
 917
 918         governor = try_then_request_governor(governor_name);
 919         if (IS_ERR(governor)) {
 920                 dev_err(dev, "%s: Unable to find governor for the device\n",
 921                         __func__);
 922                 err = PTR_ERR(governor);
 923                 goto err_init;
 924         }
 925
 926         devfreq->governor = governor;
 927         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 928                                                 NULL);
 929         if (err) {
 930                 dev_err(dev, "%s: Unable to start governor for the device\n",
 931                         __func__);
 932                 goto err_init;
 933         }
 934         create_sysfs_files(devfreq, devfreq->governor);
 935
 936         list_add(&devfreq->node, &devfreq_list);
 937
 938         mutex_unlock(&devfreq_list_lock);
 939
 940         if (devfreq->profile->is_cooling_device) {
 941                 devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
 942                 if (IS_ERR(devfreq->cdev))
 943                         devfreq->cdev = NULL;
 944         }
 945
 946         return devfreq;
 947
 948 err_init:
 949         mutex_unlock(&devfreq_list_lock);
 950 err_devfreq:
 951         devfreq_remove_device(devfreq);
 952         devfreq = NULL;
 953 err_dev:
 954         kfree(devfreq);
 955 err_out:
 956         return ERR_PTR(err);
 957 }
 958 EXPORT_SYMBOL(devfreq_add_device);
 959
 960 /**
 961  * devfreq_remove_device() - Remove devfreq feature from a device.
 962  * @devfreq:    the devfreq instance to be removed
 963  *
 964  * The opposite of devfreq_add_device().
 965  */
 966 int devfreq_remove_device(struct devfreq *devfreq)
 967 {
 968         if (!devfreq)
 969                 return -EINVAL;
 970
 971         devfreq_cooling_unregister(devfreq->cdev);
 972
 973         if (devfreq->governor) {
 974                 devfreq->governor->event_handler(devfreq,
 975                                                  DEVFREQ_GOV_STOP, NULL);
 976                 remove_sysfs_files(devfreq, devfreq->governor);
 977         }
 978
 979         device_unregister(&devfreq->dev);
 980
 981         return 0;
 982 }
 983 EXPORT_SYMBOL(devfreq_remove_device);
 984
 985 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 986 {
 987         struct devfreq **r = res;
 988
 989         if (WARN_ON(!r || !*r))
 990                 return 0;
 991
 992         return *r == data;
 993 }
 994
 995 static void devm_devfreq_dev_release(struct device *dev, void *res)
 996 {
 997         devfreq_remove_device(*(struct devfreq **)res);
 998 }
 999
1000 /**
1001  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
1002  * @dev:        the device to add devfreq feature.
1003  * @profile:    device-specific profile to run devfreq.
1004  * @governor_name:      name of the policy to choose frequency.
1005  * @data:       private data for the governor. The devfreq framework does not
1006  *              touch this value.
1007  *
1008  * This function manages automatically the memory of devfreq device using device
1009  * resource management and simplify the free operation for memory of devfreq
1010  * device.
1011  */
1012 struct devfreq *devm_devfreq_add_device(struct device *dev,
1013                                         struct devfreq_dev_profile *profile,
1014                                         const char *governor_name,
1015                                         void *data)
1016 {
1017         struct devfreq **ptr, *devfreq;
1018
1019         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
1020         if (!ptr)
1021                 return ERR_PTR(-ENOMEM);
1022
1023         devfreq = devfreq_add_device(dev, profile, governor_name, data);
1024         if (IS_ERR(devfreq)) {
1025                 devres_free(ptr);
1026                 return devfreq;
1027         }
1028
1029         *ptr = devfreq;
1030         devres_add(dev, ptr);
1031
1032         return devfreq;
1033 }
1034 EXPORT_SYMBOL(devm_devfreq_add_device);
1035
1036 #ifdef CONFIG_OF
1037 /*
1038  * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1039  * @node - pointer to device_node
1040  *
1041  * return the instance of devfreq device
1042  */
1043 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1044 {
1045         struct devfreq *devfreq;
1046
1047         if (!node)
1048                 return ERR_PTR(-EINVAL);
1049
1050         mutex_lock(&devfreq_list_lock);
1051         list_for_each_entry(devfreq, &devfreq_list, node) {
1052                 if (devfreq->dev.parent
1053                         && devfreq->dev.parent->of_node == node) {
1054                         mutex_unlock(&devfreq_list_lock);
1055                         return devfreq;
1056                 }
1057         }
1058         mutex_unlock(&devfreq_list_lock);
1059
1060         return ERR_PTR(-ENODEV);
1061 }
1062
1063 /*
1064  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1065  * @dev - instance to the given device
1066  * @phandle_name - name of property holding a phandle value
1067  * @index - index into list of devfreq
1068  *
1069  * return the instance of devfreq device
1070  */
1071 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1072                                         const char *phandle_name, int index)
1073 {
1074         struct device_node *node;
1075         struct devfreq *devfreq;
1076
1077         if (!dev || !phandle_name)
1078                 return ERR_PTR(-EINVAL);
1079
1080         if (!dev->of_node)
1081                 return ERR_PTR(-EINVAL);
1082
1083         node = of_parse_phandle(dev->of_node, phandle_name, index);
1084         if (!node)
1085                 return ERR_PTR(-ENODEV);
1086
1087         devfreq = devfreq_get_devfreq_by_node(node);
1088         of_node_put(node);
1089
1090         return devfreq;
1091 }
1092
1093 #else
1094 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1095 {
1096         return ERR_PTR(-ENODEV);
1097 }
1098
1099 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1100                                         const char *phandle_name, int index)
1101 {
1102         return ERR_PTR(-ENODEV);
1103 }
1104 #endif /* CONFIG_OF */
1105 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1106 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1107
1108 /**
1109  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1110  * @dev:        the device from which to remove devfreq feature.
1111  * @devfreq:    the devfreq instance to be removed
1112  */
1113 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1114 {
1115         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1116                                devm_devfreq_dev_match, devfreq));
1117 }
1118 EXPORT_SYMBOL(devm_devfreq_remove_device);
1119
1120 /**
1121  * devfreq_suspend_device() - Suspend devfreq of a device.
1122  * @devfreq: the devfreq instance to be suspended
1123  *
1124  * This function is intended to be called by the pm callbacks
1125  * (e.g., runtime_suspend, suspend) of the device driver that
1126  * holds the devfreq.
1127  */
1128 int devfreq_suspend_device(struct devfreq *devfreq)
1129 {
1130         int ret;
1131
1132         if (!devfreq)
1133                 return -EINVAL;
1134
1135         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1136                 return 0;
1137
1138         if (devfreq->governor) {
1139                 ret = devfreq->governor->event_handler(devfreq,
1140                                         DEVFREQ_GOV_SUSPEND, NULL);
1141                 if (ret)
1142                         return ret;
1143         }
1144
1145         if (devfreq->suspend_freq) {
1146                 mutex_lock(&devfreq->lock);
1147                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1148                 mutex_unlock(&devfreq->lock);
1149                 if (ret)
1150                         return ret;
1151         }
1152
1153         return 0;
1154 }
1155 EXPORT_SYMBOL(devfreq_suspend_device);
1156
1157 /**
1158  * devfreq_resume_device() - Resume devfreq of a device.
1159  * @devfreq: the devfreq instance to be resumed
1160  *
1161  * This function is intended to be called by the pm callbacks
1162  * (e.g., runtime_resume, resume) of the device driver that
1163  * holds the devfreq.
1164  */
1165 int devfreq_resume_device(struct devfreq *devfreq)
1166 {
1167         int ret;
1168
1169         if (!devfreq)
1170                 return -EINVAL;
1171
1172         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1173                 return 0;
1174
1175         if (devfreq->resume_freq) {
1176                 mutex_lock(&devfreq->lock);
1177                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1178                 mutex_unlock(&devfreq->lock);
1179                 if (ret)
1180                         return ret;
1181         }
1182
1183         if (devfreq->governor) {
1184                 ret = devfreq->governor->event_handler(devfreq,
1185                                         DEVFREQ_GOV_RESUME, NULL);
1186                 if (ret)
1187                         return ret;
1188         }
1189
1190         return 0;
1191 }
1192 EXPORT_SYMBOL(devfreq_resume_device);
1193
1194 /**
1195  * devfreq_suspend() - Suspend devfreq governors and devices
1196  *
1197  * Called during system wide Suspend/Hibernate cycles for suspending governors
1198  * and devices preserving the state for resume. On some platforms the devfreq
1199  * device must have precise state (frequency) after resume in order to provide
1200  * fully operating setup.
1201  */
1202 void devfreq_suspend(void)
1203 {
1204         struct devfreq *devfreq;
1205         int ret;
1206
1207         mutex_lock(&devfreq_list_lock);
1208         list_for_each_entry(devfreq, &devfreq_list, node) {
1209                 ret = devfreq_suspend_device(devfreq);
1210                 if (ret)
1211                         dev_err(&devfreq->dev,
1212                                 "failed to suspend devfreq device\n");
1213         }
1214         mutex_unlock(&devfreq_list_lock);
1215 }
1216
1217 /**
1218  * devfreq_resume() - Resume devfreq governors and devices
1219  *
1220  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1221  * devices that are suspended with devfreq_suspend().
1222  */
1223 void devfreq_resume(void)
1224 {
1225         struct devfreq *devfreq;
1226         int ret;
1227
1228         mutex_lock(&devfreq_list_lock);
1229         list_for_each_entry(devfreq, &devfreq_list, node) {
1230                 ret = devfreq_resume_device(devfreq);
1231                 if (ret)
1232                         dev_warn(&devfreq->dev,
1233                                  "failed to resume devfreq device\n");
1234         }
1235         mutex_unlock(&devfreq_list_lock);
1236 }
1237
1238 /**
1239  * devfreq_add_governor() - Add devfreq governor
1240  * @governor:   the devfreq governor to be added
1241  */
1242 int devfreq_add_governor(struct devfreq_governor *governor)
1243 {
1244         struct devfreq_governor *g;
1245         struct devfreq *devfreq;
1246         int err = 0;
1247
1248         if (!governor) {
1249                 pr_err("%s: Invalid parameters.\n", __func__);
1250                 return -EINVAL;
1251         }
1252
1253         mutex_lock(&devfreq_list_lock);
1254         g = find_devfreq_governor(governor->name);
1255         if (!IS_ERR(g)) {
1256                 pr_err("%s: governor %s already registered\n", __func__,
1257                        g->name);
1258                 err = -EINVAL;
1259                 goto err_out;
1260         }
1261
1262         list_add(&governor->node, &devfreq_governor_list);
1263
1264         list_for_each_entry(devfreq, &devfreq_list, node) {
1265                 int ret = 0;
1266                 struct device *dev = devfreq->dev.parent;
1267
1268                 if (!strncmp(devfreq->governor->name, governor->name,
1269                              DEVFREQ_NAME_LEN)) {
1270                         /* The following should never occur */
1271                         if (devfreq->governor) {
1272                                 dev_warn(dev,
1273                                          "%s: Governor %s already present\n",
1274                                          __func__, devfreq->governor->name);
1275                                 ret = devfreq->governor->event_handler(devfreq,
1276                                                         DEVFREQ_GOV_STOP, NULL);
1277                                 if (ret) {
1278                                         dev_warn(dev,
1279                                                  "%s: Governor %s stop = %d\n",
1280                                                  __func__,
1281                                                  devfreq->governor->name, ret);
1282                                 }
1283                                 /* Fall through */
1284                         }
1285                         devfreq->governor = governor;
1286                         ret = devfreq->governor->event_handler(devfreq,
1287                                                 DEVFREQ_GOV_START, NULL);
1288                         if (ret) {
1289                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1290                                          __func__, devfreq->governor->name,
1291                                          ret);
1292                         }
1293                 }
1294         }
1295
1296 err_out:
1297         mutex_unlock(&devfreq_list_lock);
1298
1299         return err;
1300 }
1301 EXPORT_SYMBOL(devfreq_add_governor);
1302
1303 /**
1304  * devfreq_remove_governor() - Remove devfreq feature from a device.
1305  * @governor:   the devfreq governor to be removed
1306  */
1307 int devfreq_remove_governor(struct devfreq_governor *governor)
1308 {
1309         struct devfreq_governor *g;
1310         struct devfreq *devfreq;
1311         int err = 0;
1312
1313         if (!governor) {
1314                 pr_err("%s: Invalid parameters.\n", __func__);
1315                 return -EINVAL;
1316         }
1317
1318         mutex_lock(&devfreq_list_lock);
1319         g = find_devfreq_governor(governor->name);
1320         if (IS_ERR(g)) {
1321                 pr_err("%s: governor %s not registered\n", __func__,
1322                        governor->name);
1323                 err = PTR_ERR(g);
1324                 goto err_out;
1325         }
1326         list_for_each_entry(devfreq, &devfreq_list, node) {
1327                 int ret;
1328                 struct device *dev = devfreq->dev.parent;
1329
1330                 if (!strncmp(devfreq->governor->name, governor->name,
1331                              DEVFREQ_NAME_LEN)) {
1332                         /* we should have a devfreq governor! */
1333                         if (!devfreq->governor) {
1334                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1335                                          __func__, governor->name);
1336                                 continue;
1337                                 /* Fall through */
1338                         }
1339                         ret = devfreq->governor->event_handler(devfreq,
1340                                                 DEVFREQ_GOV_STOP, NULL);
1341                         if (ret) {
1342                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1343                                          __func__, devfreq->governor->name,
1344                                          ret);
1345                         }
1346                         devfreq->governor = NULL;
1347                 }
1348         }
1349
1350         list_del(&governor->node);
1351 err_out:
1352         mutex_unlock(&devfreq_list_lock);
1353
1354         return err;
1355 }
1356 EXPORT_SYMBOL(devfreq_remove_governor);
1357
1358 static ssize_t name_show(struct device *dev,
1359                         struct device_attribute *attr, char *buf)
1360 {
1361         struct devfreq *df = to_devfreq(dev);
1362         return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1363 }
1364 static DEVICE_ATTR_RO(name);
1365
1366 static ssize_t governor_show(struct device *dev,
1367                              struct device_attribute *attr, char *buf)
1368 {
1369         struct devfreq *df = to_devfreq(dev);
1370
1371         if (!df->governor)
1372                 return -EINVAL;
1373
1374         return sprintf(buf, "%s\n", df->governor->name);
1375 }
1376
1377 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1378                               const char *buf, size_t count)
1379 {
1380         struct devfreq *df = to_devfreq(dev);
1381         int ret;
1382         char str_governor[DEVFREQ_NAME_LEN + 1];
1383         const struct devfreq_governor *governor, *prev_governor;
1384
1385         if (!df->governor)
1386                 return -EINVAL;
1387
1388         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1389         if (ret != 1)
1390                 return -EINVAL;
1391
1392         mutex_lock(&devfreq_list_lock);
1393         governor = try_then_request_governor(str_governor);
1394         if (IS_ERR(governor)) {
1395                 ret = PTR_ERR(governor);
1396                 goto out;
1397         }
1398         if (df->governor == governor) {
1399                 ret = 0;
1400                 goto out;
1401         } else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
1402                 || IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
1403                 ret = -EINVAL;
1404                 goto out;
1405         }
1406
1407         /*
1408          * Stop the current governor and remove the specific sysfs files
1409          * which depend on current governor.
1410          */
1411         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1412         if (ret) {
1413                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1414                          __func__, df->governor->name, ret);
1415                 goto out;
1416         }
1417         remove_sysfs_files(df, df->governor);
1418
1419         /*
1420          * Start the new governor and create the specific sysfs files
1421          * which depend on the new governor.
1422          */
1423         prev_governor = df->governor;
1424         df->governor = governor;
1425         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1426         if (ret) {
1427                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1428                          __func__, df->governor->name, ret);
1429
1430                 /* Restore previous governor */
1431                 df->governor = prev_governor;
1432                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1433                 if (ret) {
1434                         dev_err(dev,
1435                                 "%s: reverting to Governor %s failed (%d)\n",
1436                                 __func__, prev_governor->name, ret);
1437                         df->governor = NULL;
1438                         goto out;
1439                 }
1440         }
1441
1442         /*
1443          * Create the sysfs files for the new governor. But if failed to start
1444          * the new governor, restore the sysfs files of previous governor.
1445          */
1446         create_sysfs_files(df, df->governor);
1447
1448 out:
1449         mutex_unlock(&devfreq_list_lock);
1450
1451         if (!ret)
1452                 ret = count;
1453         return ret;
1454 }
1455 static DEVICE_ATTR_RW(governor);
1456
1457 static ssize_t available_governors_show(struct device *d,
1458                                         struct device_attribute *attr,
1459                                         char *buf)
1460 {
1461         struct devfreq *df = to_devfreq(d);
1462         ssize_t count = 0;
1463
1464         if (!df->governor)
1465                 return -EINVAL;
1466
1467         mutex_lock(&devfreq_list_lock);
1468
1469         /*
1470          * The devfreq with immutable governor (e.g., passive) shows
1471          * only own governor.
1472          */
1473         if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
1474                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1475                                   "%s ", df->governor->name);
1476         /*
1477          * The devfreq device shows the registered governor except for
1478          * immutable governors such as passive governor .
1479          */
1480         } else {
1481                 struct devfreq_governor *governor;
1482
1483                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1484                         if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
1485                                 continue;
1486                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1487                                            "%s ", governor->name);
1488                 }
1489         }
1490
1491         mutex_unlock(&devfreq_list_lock);
1492
1493         /* Truncate the trailing space */
1494         if (count)
1495                 count--;
1496
1497         count += sprintf(&buf[count], "\n");
1498
1499         return count;
1500 }
1501 static DEVICE_ATTR_RO(available_governors);
1502
1503 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1504                              char *buf)
1505 {
1506         unsigned long freq;
1507         struct devfreq *df = to_devfreq(dev);
1508
1509         if (!df->profile)
1510                 return -EINVAL;
1511
1512         if (df->profile->get_cur_freq &&
1513                 !df->profile->get_cur_freq(df->dev.parent, &freq))
1514                 return sprintf(buf, "%lu\n", freq);
1515
1516         return sprintf(buf, "%lu\n", df->previous_freq);
1517 }
1518 static DEVICE_ATTR_RO(cur_freq);
1519
1520 static ssize_t target_freq_show(struct device *dev,
1521                                 struct device_attribute *attr, char *buf)
1522 {
1523         struct devfreq *df = to_devfreq(dev);
1524
1525         return sprintf(buf, "%lu\n", df->previous_freq);
1526 }
1527 static DEVICE_ATTR_RO(target_freq);
1528
1529 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1530                               const char *buf, size_t count)
1531 {
1532         struct devfreq *df = to_devfreq(dev);
1533         unsigned long value;
1534         int ret;
1535
1536         /*
1537          * Protect against theoretical sysfs writes between
1538          * device_add and dev_pm_qos_add_request
1539          */
1540         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1541                 return -EAGAIN;
1542
1543         ret = sscanf(buf, "%lu", &value);
1544         if (ret != 1)
1545                 return -EINVAL;
1546
1547         /* Round down to kHz for PM QoS */
1548         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1549                                         value / HZ_PER_KHZ);
1550         if (ret < 0)
1551                 return ret;
1552
1553         return count;
1554 }
1555
1556 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1557                              char *buf)
1558 {
1559         struct devfreq *df = to_devfreq(dev);
1560         unsigned long min_freq, max_freq;
1561
1562         mutex_lock(&df->lock);
1563         get_freq_range(df, &min_freq, &max_freq);
1564         mutex_unlock(&df->lock);
1565
1566         return sprintf(buf, "%lu\n", min_freq);
1567 }
1568 static DEVICE_ATTR_RW(min_freq);
1569
1570 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1571                               const char *buf, size_t count)
1572 {
1573         struct devfreq *df = to_devfreq(dev);
1574         unsigned long value;
1575         int ret;
1576
1577         /*
1578          * Protect against theoretical sysfs writes between
1579          * device_add and dev_pm_qos_add_request
1580          */
1581         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1582                 return -EINVAL;
1583
1584         ret = sscanf(buf, "%lu", &value);
1585         if (ret != 1)
1586                 return -EINVAL;
1587
1588         /*
1589          * PM QoS frequencies are in kHz so we need to convert. Convert by
1590          * rounding upwards so that the acceptable interval never shrinks.
1591          *
1592          * For example if the user writes "666666666" to sysfs this value will
1593          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1594          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1595          *
1596          * A value of zero means "no limit".
1597          */
1598         if (value)
1599                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1600         else
1601                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1602
1603         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1604         if (ret < 0)
1605                 return ret;
1606
1607         return count;
1608 }
1609
1610 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1611                              char *buf)
1612 {
1613         struct devfreq *df = to_devfreq(dev);
1614         unsigned long min_freq, max_freq;
1615
1616         mutex_lock(&df->lock);
1617         get_freq_range(df, &min_freq, &max_freq);
1618         mutex_unlock(&df->lock);
1619
1620         return sprintf(buf, "%lu\n", max_freq);
1621 }
1622 static DEVICE_ATTR_RW(max_freq);
1623
1624 static ssize_t available_frequencies_show(struct device *d,
1625                                           struct device_attribute *attr,
1626                                           char *buf)
1627 {
1628         struct devfreq *df = to_devfreq(d);
1629         ssize_t count = 0;
1630         int i;
1631
1632         if (!df->profile)
1633                 return -EINVAL;
1634
1635         mutex_lock(&df->lock);
1636
1637         for (i = 0; i < df->profile->max_state; i++)
1638                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1639                                 "%lu ", df->profile->freq_table[i]);
1640
1641         mutex_unlock(&df->lock);
1642         /* Truncate the trailing space */
1643         if (count)
1644                 count--;
1645
1646         count += sprintf(&buf[count], "\n");
1647
1648         return count;
1649 }
1650 static DEVICE_ATTR_RO(available_frequencies);
1651
1652 static ssize_t trans_stat_show(struct device *dev,
1653                                struct device_attribute *attr, char *buf)
1654 {
1655         struct devfreq *df = to_devfreq(dev);
1656         ssize_t len;
1657         int i, j;
1658         unsigned int max_state;
1659
1660         if (!df->profile)
1661                 return -EINVAL;
1662         max_state = df->profile->max_state;
1663
1664         if (max_state == 0)
1665                 return sprintf(buf, "Not Supported.\n");
1666
1667         mutex_lock(&df->lock);
1668         if (!df->stop_polling &&
1669                         devfreq_update_status(df, df->previous_freq)) {
1670                 mutex_unlock(&df->lock);
1671                 return 0;
1672         }
1673         mutex_unlock(&df->lock);
1674
1675         len = sprintf(buf, "     From  :   To\n");
1676         len += sprintf(buf + len, "           :");
1677         for (i = 0; i < max_state; i++)
1678                 len += sprintf(buf + len, "%10lu",
1679                                 df->profile->freq_table[i]);
1680
1681         len += sprintf(buf + len, "   time(ms)\n");
1682
1683         for (i = 0; i < max_state; i++) {
1684                 if (df->profile->freq_table[i]
1685                                         == df->previous_freq) {
1686                         len += sprintf(buf + len, "*");
1687                 } else {
1688                         len += sprintf(buf + len, " ");
1689                 }
1690                 len += sprintf(buf + len, "%10lu:",
1691                                 df->profile->freq_table[i]);
1692                 for (j = 0; j < max_state; j++)
1693                         len += sprintf(buf + len, "%10u",
1694                                 df->stats.trans_table[(i * max_state) + j]);
1695
1696                 len += sprintf(buf + len, "%10llu\n", (u64)
1697                         jiffies64_to_msecs(df->stats.time_in_state[i]));
1698         }
1699
1700         len += sprintf(buf + len, "Total transition : %u\n",
1701                                         df->stats.total_trans);
1702         return len;
1703 }
1704
1705 static ssize_t trans_stat_store(struct device *dev,
1706                                 struct device_attribute *attr,
1707                                 const char *buf, size_t count)
1708 {
1709         struct devfreq *df = to_devfreq(dev);
1710         int err, value;
1711
1712         if (!df->profile)
1713                 return -EINVAL;
1714
1715         if (df->profile->max_state == 0)
1716                 return count;
1717
1718         err = kstrtoint(buf, 10, &value);
1719         if (err || value != 0)
1720                 return -EINVAL;
1721
1722         mutex_lock(&df->lock);
1723         memset(df->stats.time_in_state, 0, (df->profile->max_state *
1724                                         sizeof(*df->stats.time_in_state)));
1725         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1726                                         df->profile->max_state,
1727                                         df->profile->max_state));
1728         df->stats.total_trans = 0;
1729         df->stats.last_update = get_jiffies_64();
1730         mutex_unlock(&df->lock);
1731
1732         return count;
1733 }
1734 static DEVICE_ATTR_RW(trans_stat);
1735
1736 static struct attribute *devfreq_attrs[] = {
1737         &dev_attr_name.attr,
1738         &dev_attr_governor.attr,
1739         &dev_attr_available_governors.attr,
1740         &dev_attr_cur_freq.attr,
1741         &dev_attr_available_frequencies.attr,
1742         &dev_attr_target_freq.attr,
1743         &dev_attr_min_freq.attr,
1744         &dev_attr_max_freq.attr,
1745         &dev_attr_trans_stat.attr,
1746         NULL,
1747 };
1748 ATTRIBUTE_GROUPS(devfreq);
1749
1750 static ssize_t polling_interval_show(struct device *dev,
1751                                      struct device_attribute *attr, char *buf)
1752 {
1753         struct devfreq *df = to_devfreq(dev);
1754
1755         if (!df->profile)
1756                 return -EINVAL;
1757
1758         return sprintf(buf, "%d\n", df->profile->polling_ms);
1759 }
1760
1761 static ssize_t polling_interval_store(struct device *dev,
1762                                       struct device_attribute *attr,
1763                                       const char *buf, size_t count)
1764 {
1765         struct devfreq *df = to_devfreq(dev);
1766         unsigned int value;
1767         int ret;
1768
1769         if (!df->governor)
1770                 return -EINVAL;
1771
1772         ret = sscanf(buf, "%u", &value);
1773         if (ret != 1)
1774                 return -EINVAL;
1775
1776         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1777         ret = count;
1778
1779         return ret;
1780 }
1781 static DEVICE_ATTR_RW(polling_interval);
1782
1783 static ssize_t timer_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, "%s\n", timer_name[df->profile->timer]);
1792 }
1793
1794 static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1795                               const char *buf, size_t count)
1796 {
1797         struct devfreq *df = to_devfreq(dev);
1798         char str_timer[DEVFREQ_NAME_LEN + 1];
1799         int timer = -1;
1800         int ret = 0, i;
1801
1802         if (!df->governor || !df->profile)
1803                 return -EINVAL;
1804
1805         ret = sscanf(buf, "%16s", str_timer);
1806         if (ret != 1)
1807                 return -EINVAL;
1808
1809         for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1810                 if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1811                         timer = i;
1812                         break;
1813                 }
1814         }
1815
1816         if (timer < 0) {
1817                 ret = -EINVAL;
1818                 goto out;
1819         }
1820
1821         if (df->profile->timer == timer) {
1822                 ret = 0;
1823                 goto out;
1824         }
1825
1826         mutex_lock(&df->lock);
1827         df->profile->timer = timer;
1828         mutex_unlock(&df->lock);
1829
1830         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1831         if (ret) {
1832                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1833                          __func__, df->governor->name, ret);
1834                 goto out;
1835         }
1836
1837         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1838         if (ret)
1839                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1840                          __func__, df->governor->name, ret);
1841 out:
1842         return ret ? ret : count;
1843 }
1844 static DEVICE_ATTR_RW(timer);
1845
1846 #define CREATE_SYSFS_FILE(df, name)                                     \
1847 {                                                                       \
1848         int ret;                                                        \
1849         ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);  \
1850         if (ret < 0) {                                                  \
1851                 dev_warn(&df->dev,                                      \
1852                         "Unable to create attr(%s)\n", "##name");       \
1853         }                                                               \
1854 }                                                                       \
1855
1856 /* Create the specific sysfs files which depend on each governor. */
1857 static void create_sysfs_files(struct devfreq *devfreq,
1858                                 const struct devfreq_governor *gov)
1859 {
1860         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1861                 CREATE_SYSFS_FILE(devfreq, polling_interval);
1862         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1863                 CREATE_SYSFS_FILE(devfreq, timer);
1864 }
1865
1866 /* Remove the specific sysfs files which depend on each governor. */
1867 static void remove_sysfs_files(struct devfreq *devfreq,
1868                                 const struct devfreq_governor *gov)
1869 {
1870         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1871                 sysfs_remove_file(&devfreq->dev.kobj,
1872                                 &dev_attr_polling_interval.attr);
1873         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1874                 sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
1875 }
1876
1877 /**
1878  * devfreq_summary_show() - Show the summary of the devfreq devices
1879  * @s:          seq_file instance to show the summary of devfreq devices
1880  * @data:       not used
1881  *
1882  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1883  * It helps that user can know the detailed information of the devfreq devices.
1884  *
1885  * Return 0 always because it shows the information without any data change.
1886  */
1887 static int devfreq_summary_show(struct seq_file *s, void *data)
1888 {
1889         struct devfreq *devfreq;
1890         struct devfreq *p_devfreq = NULL;
1891         unsigned long cur_freq, min_freq, max_freq;
1892         unsigned int polling_ms;
1893         unsigned int timer;
1894
1895         seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1896                         "dev",
1897                         "parent_dev",
1898                         "governor",
1899                         "timer",
1900                         "polling_ms",
1901                         "cur_freq_Hz",
1902                         "min_freq_Hz",
1903                         "max_freq_Hz");
1904         seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1905                         "------------------------------",
1906                         "------------------------------",
1907                         "---------------",
1908                         "----------",
1909                         "----------",
1910                         "------------",
1911                         "------------",
1912                         "------------");
1913
1914         mutex_lock(&devfreq_list_lock);
1915
1916         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1917 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1918                 if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
1919                                                         DEVFREQ_NAME_LEN)) {
1920                         struct devfreq_passive_data *data = devfreq->data;
1921
1922                         if (data)
1923                                 p_devfreq = data->parent;
1924                 } else {
1925                         p_devfreq = NULL;
1926                 }
1927 #endif
1928
1929                 mutex_lock(&devfreq->lock);
1930                 cur_freq = devfreq->previous_freq;
1931                 get_freq_range(devfreq, &min_freq, &max_freq);
1932                 timer = devfreq->profile->timer;
1933
1934                 if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
1935                         polling_ms = devfreq->profile->polling_ms;
1936                 else
1937                         polling_ms = 0;
1938                 mutex_unlock(&devfreq->lock);
1939
1940                 seq_printf(s,
1941                         "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
1942                         dev_name(&devfreq->dev),
1943                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1944                         devfreq->governor->name,
1945                         polling_ms ? timer_name[timer] : "null",
1946                         polling_ms,
1947                         cur_freq,
1948                         min_freq,
1949                         max_freq);
1950         }
1951
1952         mutex_unlock(&devfreq_list_lock);
1953
1954         return 0;
1955 }
1956 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1957
1958 static int __init devfreq_init(void)
1959 {
1960         devfreq_class = class_create(THIS_MODULE, "devfreq");
1961         if (IS_ERR(devfreq_class)) {
1962                 pr_err("%s: couldn't create class\n", __FILE__);
1963                 return PTR_ERR(devfreq_class);
1964         }
1965
1966         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1967         if (!devfreq_wq) {
1968                 class_destroy(devfreq_class);
1969                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1970                 return -ENOMEM;
1971         }
1972         devfreq_class->dev_groups = devfreq_groups;
1973
1974         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
1975         debugfs_create_file("devfreq_summary", 0444,
1976                                 devfreq_debugfs, NULL,
1977                                 &devfreq_summary_fops);
1978
1979         return 0;
1980 }
1981 subsys_initcall(devfreq_init);
1982
1983 /*
1984  * The following are helper functions for devfreq user device drivers with
1985  * OPP framework.
1986  */
1987
1988 /**
1989  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1990  *                           freq value given to target callback.
1991  * @dev:        The devfreq user device. (parent of devfreq)
1992  * @freq:       The frequency given to target function
1993  * @flags:      Flags handed from devfreq framework.
1994  *
1995  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1996  * use.
1997  */
1998 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1999                                            unsigned long *freq,
2000                                            u32 flags)
2001 {
2002         struct dev_pm_opp *opp;
2003
2004         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
2005                 /* The freq is an upper bound. opp should be lower */
2006                 opp = dev_pm_opp_find_freq_floor(dev, freq);
2007
2008                 /* If not available, use the closest opp */
2009                 if (opp == ERR_PTR(-ERANGE))
2010                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
2011         } else {
2012                 /* The freq is an lower bound. opp should be higher */
2013                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
2014
2015                 /* If not available, use the closest opp */
2016                 if (opp == ERR_PTR(-ERANGE))
2017                         opp = dev_pm_opp_find_freq_floor(dev, freq);
2018         }
2019
2020         return opp;
2021 }
2022 EXPORT_SYMBOL(devfreq_recommended_opp);
2023
2024 /**
2025  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
2026  *                                   for any changes in the OPP availability
2027  *                                   changes
2028  * @dev:        The devfreq user device. (parent of devfreq)
2029  * @devfreq:    The devfreq object.
2030  */
2031 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
2032 {
2033         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
2034 }
2035 EXPORT_SYMBOL(devfreq_register_opp_notifier);
2036
2037 /**
2038  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
2039  *                                     notified for any changes in the OPP
2040  *                                     availability changes anymore.
2041  * @dev:        The devfreq user device. (parent of devfreq)
2042  * @devfreq:    The devfreq object.
2043  *
2044  * At exit() callback of devfreq_dev_profile, this must be included if
2045  * devfreq_recommended_opp is used.
2046  */
2047 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
2048 {
2049         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
2050 }
2051 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
2052
2053 static void devm_devfreq_opp_release(struct device *dev, void *res)
2054 {
2055         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
2056 }
2057
2058 /**
2059  * devm_devfreq_register_opp_notifier() - Resource-managed
2060  *                                        devfreq_register_opp_notifier()
2061  * @dev:        The devfreq user device. (parent of devfreq)
2062  * @devfreq:    The devfreq object.
2063  */
2064 int devm_devfreq_register_opp_notifier(struct device *dev,
2065                                        struct devfreq *devfreq)
2066 {
2067         struct devfreq **ptr;
2068         int ret;
2069
2070         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
2071         if (!ptr)
2072                 return -ENOMEM;
2073
2074         ret = devfreq_register_opp_notifier(dev, devfreq);
2075         if (ret) {
2076                 devres_free(ptr);
2077                 return ret;
2078         }
2079
2080         *ptr = devfreq;
2081         devres_add(dev, ptr);
2082
2083         return 0;
2084 }
2085 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2086
2087 /**
2088  * devm_devfreq_unregister_opp_notifier() - Resource-managed
2089  *                                          devfreq_unregister_opp_notifier()
2090  * @dev:        The devfreq user device. (parent of devfreq)
2091  * @devfreq:    The devfreq object.
2092  */
2093 void devm_devfreq_unregister_opp_notifier(struct device *dev,
2094                                          struct devfreq *devfreq)
2095 {
2096         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2097                                devm_devfreq_dev_match, devfreq));
2098 }
2099 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2100
2101 /**
2102  * devfreq_register_notifier() - Register a driver with devfreq
2103  * @devfreq:    The devfreq object.
2104  * @nb:         The notifier block to register.
2105  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2106  */
2107 int devfreq_register_notifier(struct devfreq *devfreq,
2108                               struct notifier_block *nb,
2109                               unsigned int list)
2110 {
2111         int ret = 0;
2112
2113         if (!devfreq)
2114                 return -EINVAL;
2115
2116         switch (list) {
2117         case DEVFREQ_TRANSITION_NOTIFIER:
2118                 ret = srcu_notifier_chain_register(
2119                                 &devfreq->transition_notifier_list, nb);
2120                 break;
2121         default:
2122                 ret = -EINVAL;
2123         }
2124
2125         return ret;
2126 }
2127 EXPORT_SYMBOL(devfreq_register_notifier);
2128
2129 /*
2130  * devfreq_unregister_notifier() - Unregister a driver with devfreq
2131  * @devfreq:    The devfreq object.
2132  * @nb:         The notifier block to be unregistered.
2133  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2134  */
2135 int devfreq_unregister_notifier(struct devfreq *devfreq,
2136                                 struct notifier_block *nb,
2137                                 unsigned int list)
2138 {
2139         int ret = 0;
2140
2141         if (!devfreq)
2142                 return -EINVAL;
2143
2144         switch (list) {
2145         case DEVFREQ_TRANSITION_NOTIFIER:
2146                 ret = srcu_notifier_chain_unregister(
2147                                 &devfreq->transition_notifier_list, nb);
2148                 break;
2149         default:
2150                 ret = -EINVAL;
2151         }
2152
2153         return ret;
2154 }
2155 EXPORT_SYMBOL(devfreq_unregister_notifier);
2156
2157 struct devfreq_notifier_devres {
2158         struct devfreq *devfreq;
2159         struct notifier_block *nb;
2160         unsigned int list;
2161 };
2162
2163 static void devm_devfreq_notifier_release(struct device *dev, void *res)
2164 {
2165         struct devfreq_notifier_devres *this = res;
2166
2167         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2168 }
2169
2170 /**
2171  * devm_devfreq_register_notifier()
2172  *      - Resource-managed devfreq_register_notifier()
2173  * @dev:        The devfreq user device. (parent of devfreq)
2174  * @devfreq:    The devfreq object.
2175  * @nb:         The notifier block to be unregistered.
2176  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2177  */
2178 int devm_devfreq_register_notifier(struct device *dev,
2179                                 struct devfreq *devfreq,
2180                                 struct notifier_block *nb,
2181                                 unsigned int list)
2182 {
2183         struct devfreq_notifier_devres *ptr;
2184         int ret;
2185
2186         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2187                                 GFP_KERNEL);
2188         if (!ptr)
2189                 return -ENOMEM;
2190
2191         ret = devfreq_register_notifier(devfreq, nb, list);
2192         if (ret) {
2193                 devres_free(ptr);
2194                 return ret;
2195         }
2196
2197         ptr->devfreq = devfreq;
2198         ptr->nb = nb;
2199         ptr->list = list;
2200         devres_add(dev, ptr);
2201
2202         return 0;
2203 }
2204 EXPORT_SYMBOL(devm_devfreq_register_notifier);
2205
2206 /**
2207  * devm_devfreq_unregister_notifier()
2208  *      - Resource-managed devfreq_unregister_notifier()
2209  * @dev:        The devfreq user device. (parent of devfreq)
2210  * @devfreq:    The devfreq object.
2211  * @nb:         The notifier block to be unregistered.
2212  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2213  */
2214 void devm_devfreq_unregister_notifier(struct device *dev,
2215                                       struct devfreq *devfreq,
2216                                       struct notifier_block *nb,
2217                                       unsigned int list)
2218 {
2219         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2220                                devm_devfreq_dev_match, devfreq));
2221 }
2222 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);