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  * @val:        not used
 700  * @ptr:        not used
 701  */
 702 static int qos_min_notifier_call(struct notifier_block *nb,
 703                                          unsigned long val, void *ptr)
 704 {
 705         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 706 }
 707
 708 /**
 709  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 710  * @nb:         Should be devfreq->nb_max
 711  * @val:        not used
 712  * @ptr:        not used
 713  */
 714 static int qos_max_notifier_call(struct notifier_block *nb,
 715                                          unsigned long val, void *ptr)
 716 {
 717         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 718 }
 719
 720 /**
 721  * devfreq_dev_release() - Callback for struct device to release the device.
 722  * @dev:        the devfreq device
 723  *
 724  * Remove devfreq from the list and release its resources.
 725  */
 726 static void devfreq_dev_release(struct device *dev)
 727 {
 728         struct devfreq *devfreq = to_devfreq(dev);
 729         int err;
 730
 731         mutex_lock(&devfreq_list_lock);
 732         list_del(&devfreq->node);
 733         mutex_unlock(&devfreq_list_lock);
 734
 735         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 736                                          DEV_PM_QOS_MAX_FREQUENCY);
 737         if (err && err != -ENOENT)
 738                 dev_warn(dev->parent,
 739                         "Failed to remove max_freq notifier: %d\n", err);
 740         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 741                                          DEV_PM_QOS_MIN_FREQUENCY);
 742         if (err && err != -ENOENT)
 743                 dev_warn(dev->parent,
 744                         "Failed to remove min_freq notifier: %d\n", err);
 745
 746         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 747                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 748                 if (err < 0)
 749                         dev_warn(dev->parent,
 750                                 "Failed to remove max_freq request: %d\n", err);
 751         }
 752         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 753                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 754                 if (err < 0)
 755                         dev_warn(dev->parent,
 756                                 "Failed to remove min_freq request: %d\n", err);
 757         }
 758
 759         if (devfreq->profile->exit)
 760                 devfreq->profile->exit(devfreq->dev.parent);
 761
 762         if (devfreq->opp_table)
 763                 dev_pm_opp_put_opp_table(devfreq->opp_table);
 764
 765         mutex_destroy(&devfreq->lock);
 766         kfree(devfreq);
 767 }
 768
 769 static void create_sysfs_files(struct devfreq *devfreq,
 770                                 const struct devfreq_governor *gov);
 771 static void remove_sysfs_files(struct devfreq *devfreq,
 772                                 const struct devfreq_governor *gov);
 773
 774 /**
 775  * devfreq_add_device() - Add devfreq feature to the device
 776  * @dev:        the device to add devfreq feature.
 777  * @profile:    device-specific profile to run devfreq.
 778  * @governor_name:      name of the policy to choose frequency.
 779  * @data:       devfreq driver pass to governors, governor should not change it.
 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         unsigned long min_freq, max_freq;
 789         int err = 0;
 790
 791         if (!dev || !profile || !governor_name) {
 792                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 793                 return ERR_PTR(-EINVAL);
 794         }
 795
 796         mutex_lock(&devfreq_list_lock);
 797         devfreq = find_device_devfreq(dev);
 798         mutex_unlock(&devfreq_list_lock);
 799         if (!IS_ERR(devfreq)) {
 800                 dev_err(dev, "%s: devfreq device already exists!\n",
 801                         __func__);
 802                 err = -EINVAL;
 803                 goto err_out;
 804         }
 805
 806         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 807         if (!devfreq) {
 808                 err = -ENOMEM;
 809                 goto err_out;
 810         }
 811
 812         mutex_init(&devfreq->lock);
 813         mutex_lock(&devfreq->lock);
 814         devfreq->dev.parent = dev;
 815         devfreq->dev.class = devfreq_class;
 816         devfreq->dev.release = devfreq_dev_release;
 817         INIT_LIST_HEAD(&devfreq->node);
 818         devfreq->profile = profile;
 819         devfreq->previous_freq = profile->initial_freq;
 820         devfreq->last_status.current_frequency = profile->initial_freq;
 821         devfreq->data = data;
 822         devfreq->nb.notifier_call = devfreq_notifier_call;
 823
 824         if (devfreq->profile->timer < 0
 825                 || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 826                 mutex_unlock(&devfreq->lock);
 827                 err = -EINVAL;
 828                 goto err_dev;
 829         }
 830
 831         if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
 832                 mutex_unlock(&devfreq->lock);
 833                 err = set_freq_table(devfreq);
 834                 if (err < 0)
 835                         goto err_dev;
 836                 mutex_lock(&devfreq->lock);
 837         } else {
 838                 devfreq->freq_table = devfreq->profile->freq_table;
 839                 devfreq->max_state = devfreq->profile->max_state;
 840         }
 841
 842         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 843         if (!devfreq->scaling_min_freq) {
 844                 mutex_unlock(&devfreq->lock);
 845                 err = -EINVAL;
 846                 goto err_dev;
 847         }
 848
 849         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 850         if (!devfreq->scaling_max_freq) {
 851                 mutex_unlock(&devfreq->lock);
 852                 err = -EINVAL;
 853                 goto err_dev;
 854         }
 855
 856         devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 857
 858         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 859         devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
 860         if (IS_ERR(devfreq->opp_table))
 861                 devfreq->opp_table = NULL;
 862
 863         atomic_set(&devfreq->suspend_count, 0);
 864
 865         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 866         err = device_register(&devfreq->dev);
 867         if (err) {
 868                 mutex_unlock(&devfreq->lock);
 869                 put_device(&devfreq->dev);
 870                 goto err_out;
 871         }
 872
 873         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 874                         array3_size(sizeof(unsigned int),
 875                                     devfreq->max_state,
 876                                     devfreq->max_state),
 877                         GFP_KERNEL);
 878         if (!devfreq->stats.trans_table) {
 879                 mutex_unlock(&devfreq->lock);
 880                 err = -ENOMEM;
 881                 goto err_devfreq;
 882         }
 883
 884         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 885                         devfreq->max_state,
 886                         sizeof(*devfreq->stats.time_in_state),
 887                         GFP_KERNEL);
 888         if (!devfreq->stats.time_in_state) {
 889                 mutex_unlock(&devfreq->lock);
 890                 err = -ENOMEM;
 891                 goto err_devfreq;
 892         }
 893
 894         devfreq->stats.total_trans = 0;
 895         devfreq->stats.last_update = get_jiffies_64();
 896
 897         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 898
 899         mutex_unlock(&devfreq->lock);
 900
 901         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 902                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 903         if (err < 0)
 904                 goto err_devfreq;
 905         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 906                                      DEV_PM_QOS_MAX_FREQUENCY,
 907                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 908         if (err < 0)
 909                 goto err_devfreq;
 910
 911         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 912         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
 913                                       DEV_PM_QOS_MIN_FREQUENCY);
 914         if (err)
 915                 goto err_devfreq;
 916
 917         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 918         err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
 919                                       DEV_PM_QOS_MAX_FREQUENCY);
 920         if (err)
 921                 goto err_devfreq;
 922
 923         mutex_lock(&devfreq_list_lock);
 924
 925         governor = try_then_request_governor(governor_name);
 926         if (IS_ERR(governor)) {
 927                 dev_err(dev, "%s: Unable to find governor for the device\n",
 928                         __func__);
 929                 err = PTR_ERR(governor);
 930                 goto err_init;
 931         }
 932
 933         devfreq->governor = governor;
 934         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 935                                                 NULL);
 936         if (err) {
 937                 dev_err_probe(dev, err,
 938                         "%s: Unable to start governor for the device\n",
 939                          __func__);
 940                 goto err_init;
 941         }
 942         create_sysfs_files(devfreq, devfreq->governor);
 943
 944         list_add(&devfreq->node, &devfreq_list);
 945
 946         mutex_unlock(&devfreq_list_lock);
 947
 948         if (devfreq->profile->is_cooling_device) {
 949                 devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
 950                 if (IS_ERR(devfreq->cdev))
 951                         devfreq->cdev = NULL;
 952         }
 953
 954         return devfreq;
 955
 956 err_init:
 957         mutex_unlock(&devfreq_list_lock);
 958 err_devfreq:
 959         devfreq_remove_device(devfreq);
 960         devfreq = NULL;
 961 err_dev:
 962         kfree(devfreq);
 963 err_out:
 964         return ERR_PTR(err);
 965 }
 966 EXPORT_SYMBOL(devfreq_add_device);
 967
 968 /**
 969  * devfreq_remove_device() - Remove devfreq feature from a device.
 970  * @devfreq:    the devfreq instance to be removed
 971  *
 972  * The opposite of devfreq_add_device().
 973  */
 974 int devfreq_remove_device(struct devfreq *devfreq)
 975 {
 976         if (!devfreq)
 977                 return -EINVAL;
 978
 979         devfreq_cooling_unregister(devfreq->cdev);
 980
 981         if (devfreq->governor) {
 982                 devfreq->governor->event_handler(devfreq,
 983                                                  DEVFREQ_GOV_STOP, NULL);
 984                 remove_sysfs_files(devfreq, devfreq->governor);
 985         }
 986
 987         device_unregister(&devfreq->dev);
 988
 989         return 0;
 990 }
 991 EXPORT_SYMBOL(devfreq_remove_device);
 992
 993 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 994 {
 995         struct devfreq **r = res;
 996
 997         if (WARN_ON(!r || !*r))
 998                 return 0;
 999
1000         return *r == data;
1001 }
1002
1003 static void devm_devfreq_dev_release(struct device *dev, void *res)
1004 {
1005         devfreq_remove_device(*(struct devfreq **)res);
1006 }
1007
1008 /**
1009  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
1010  * @dev:        the device to add devfreq feature.
1011  * @profile:    device-specific profile to run devfreq.
1012  * @governor_name:      name of the policy to choose frequency.
1013  * @data:        devfreq driver pass to governors, governor should not change it.
1014  *
1015  * This function manages automatically the memory of devfreq device using device
1016  * resource management and simplify the free operation for memory of devfreq
1017  * device.
1018  */
1019 struct devfreq *devm_devfreq_add_device(struct device *dev,
1020                                         struct devfreq_dev_profile *profile,
1021                                         const char *governor_name,
1022                                         void *data)
1023 {
1024         struct devfreq **ptr, *devfreq;
1025
1026         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
1027         if (!ptr)
1028                 return ERR_PTR(-ENOMEM);
1029
1030         devfreq = devfreq_add_device(dev, profile, governor_name, data);
1031         if (IS_ERR(devfreq)) {
1032                 devres_free(ptr);
1033                 return devfreq;
1034         }
1035
1036         *ptr = devfreq;
1037         devres_add(dev, ptr);
1038
1039         return devfreq;
1040 }
1041 EXPORT_SYMBOL(devm_devfreq_add_device);
1042
1043 #ifdef CONFIG_OF
1044 /*
1045  * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1046  * @node - pointer to device_node
1047  *
1048  * return the instance of devfreq device
1049  */
1050 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1051 {
1052         struct devfreq *devfreq;
1053
1054         if (!node)
1055                 return ERR_PTR(-EINVAL);
1056
1057         mutex_lock(&devfreq_list_lock);
1058         list_for_each_entry(devfreq, &devfreq_list, node) {
1059                 if (devfreq->dev.parent
1060                         && device_match_of_node(devfreq->dev.parent, node)) {
1061                         mutex_unlock(&devfreq_list_lock);
1062                         return devfreq;
1063                 }
1064         }
1065         mutex_unlock(&devfreq_list_lock);
1066
1067         return ERR_PTR(-ENODEV);
1068 }
1069
1070 /*
1071  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1072  * @dev - instance to the given device
1073  * @phandle_name - name of property holding a phandle value
1074  * @index - index into list of devfreq
1075  *
1076  * return the instance of devfreq device
1077  */
1078 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1079                                         const char *phandle_name, int index)
1080 {
1081         struct device_node *node;
1082         struct devfreq *devfreq;
1083
1084         if (!dev || !phandle_name)
1085                 return ERR_PTR(-EINVAL);
1086
1087         if (!dev->of_node)
1088                 return ERR_PTR(-EINVAL);
1089
1090         node = of_parse_phandle(dev->of_node, phandle_name, index);
1091         if (!node)
1092                 return ERR_PTR(-ENODEV);
1093
1094         devfreq = devfreq_get_devfreq_by_node(node);
1095         of_node_put(node);
1096
1097         return devfreq;
1098 }
1099
1100 #else
1101 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1102 {
1103         return ERR_PTR(-ENODEV);
1104 }
1105
1106 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1107                                         const char *phandle_name, int index)
1108 {
1109         return ERR_PTR(-ENODEV);
1110 }
1111 #endif /* CONFIG_OF */
1112 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1113 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1114
1115 /**
1116  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1117  * @dev:        the device from which to remove devfreq feature.
1118  * @devfreq:    the devfreq instance to be removed
1119  */
1120 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1121 {
1122         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1123                                devm_devfreq_dev_match, devfreq));
1124 }
1125 EXPORT_SYMBOL(devm_devfreq_remove_device);
1126
1127 /**
1128  * devfreq_suspend_device() - Suspend devfreq of a device.
1129  * @devfreq: the devfreq instance to be suspended
1130  *
1131  * This function is intended to be called by the pm callbacks
1132  * (e.g., runtime_suspend, suspend) of the device driver that
1133  * holds the devfreq.
1134  */
1135 int devfreq_suspend_device(struct devfreq *devfreq)
1136 {
1137         int ret;
1138
1139         if (!devfreq)
1140                 return -EINVAL;
1141
1142         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1143                 return 0;
1144
1145         if (devfreq->governor) {
1146                 ret = devfreq->governor->event_handler(devfreq,
1147                                         DEVFREQ_GOV_SUSPEND, NULL);
1148                 if (ret)
1149                         return ret;
1150         }
1151
1152         if (devfreq->suspend_freq) {
1153                 mutex_lock(&devfreq->lock);
1154                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1155                 mutex_unlock(&devfreq->lock);
1156                 if (ret)
1157                         return ret;
1158         }
1159
1160         return 0;
1161 }
1162 EXPORT_SYMBOL(devfreq_suspend_device);
1163
1164 /**
1165  * devfreq_resume_device() - Resume devfreq of a device.
1166  * @devfreq: the devfreq instance to be resumed
1167  *
1168  * This function is intended to be called by the pm callbacks
1169  * (e.g., runtime_resume, resume) of the device driver that
1170  * holds the devfreq.
1171  */
1172 int devfreq_resume_device(struct devfreq *devfreq)
1173 {
1174         int ret;
1175
1176         if (!devfreq)
1177                 return -EINVAL;
1178
1179         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1180                 return 0;
1181
1182         if (devfreq->resume_freq) {
1183                 mutex_lock(&devfreq->lock);
1184                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1185                 mutex_unlock(&devfreq->lock);
1186                 if (ret)
1187                         return ret;
1188         }
1189
1190         if (devfreq->governor) {
1191                 ret = devfreq->governor->event_handler(devfreq,
1192                                         DEVFREQ_GOV_RESUME, NULL);
1193                 if (ret)
1194                         return ret;
1195         }
1196
1197         return 0;
1198 }
1199 EXPORT_SYMBOL(devfreq_resume_device);
1200
1201 /**
1202  * devfreq_suspend() - Suspend devfreq governors and devices
1203  *
1204  * Called during system wide Suspend/Hibernate cycles for suspending governors
1205  * and devices preserving the state for resume. On some platforms the devfreq
1206  * device must have precise state (frequency) after resume in order to provide
1207  * fully operating setup.
1208  */
1209 void devfreq_suspend(void)
1210 {
1211         struct devfreq *devfreq;
1212         int ret;
1213
1214         mutex_lock(&devfreq_list_lock);
1215         list_for_each_entry(devfreq, &devfreq_list, node) {
1216                 ret = devfreq_suspend_device(devfreq);
1217                 if (ret)
1218                         dev_err(&devfreq->dev,
1219                                 "failed to suspend devfreq device\n");
1220         }
1221         mutex_unlock(&devfreq_list_lock);
1222 }
1223
1224 /**
1225  * devfreq_resume() - Resume devfreq governors and devices
1226  *
1227  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1228  * devices that are suspended with devfreq_suspend().
1229  */
1230 void devfreq_resume(void)
1231 {
1232         struct devfreq *devfreq;
1233         int ret;
1234
1235         mutex_lock(&devfreq_list_lock);
1236         list_for_each_entry(devfreq, &devfreq_list, node) {
1237                 ret = devfreq_resume_device(devfreq);
1238                 if (ret)
1239                         dev_warn(&devfreq->dev,
1240                                  "failed to resume devfreq device\n");
1241         }
1242         mutex_unlock(&devfreq_list_lock);
1243 }
1244
1245 /**
1246  * devfreq_add_governor() - Add devfreq governor
1247  * @governor:   the devfreq governor to be added
1248  */
1249 int devfreq_add_governor(struct devfreq_governor *governor)
1250 {
1251         struct devfreq_governor *g;
1252         struct devfreq *devfreq;
1253         int err = 0;
1254
1255         if (!governor) {
1256                 pr_err("%s: Invalid parameters.\n", __func__);
1257                 return -EINVAL;
1258         }
1259
1260         mutex_lock(&devfreq_list_lock);
1261         g = find_devfreq_governor(governor->name);
1262         if (!IS_ERR(g)) {
1263                 pr_err("%s: governor %s already registered\n", __func__,
1264                        g->name);
1265                 err = -EINVAL;
1266                 goto err_out;
1267         }
1268
1269         list_add(&governor->node, &devfreq_governor_list);
1270
1271         list_for_each_entry(devfreq, &devfreq_list, node) {
1272                 int ret = 0;
1273                 struct device *dev = devfreq->dev.parent;
1274
1275                 if (!strncmp(devfreq->governor->name, governor->name,
1276                              DEVFREQ_NAME_LEN)) {
1277                         /* The following should never occur */
1278                         if (devfreq->governor) {
1279                                 dev_warn(dev,
1280                                          "%s: Governor %s already present\n",
1281                                          __func__, devfreq->governor->name);
1282                                 ret = devfreq->governor->event_handler(devfreq,
1283                                                         DEVFREQ_GOV_STOP, NULL);
1284                                 if (ret) {
1285                                         dev_warn(dev,
1286                                                  "%s: Governor %s stop = %d\n",
1287                                                  __func__,
1288                                                  devfreq->governor->name, ret);
1289                                 }
1290                                 /* Fall through */
1291                         }
1292                         devfreq->governor = governor;
1293                         ret = devfreq->governor->event_handler(devfreq,
1294                                                 DEVFREQ_GOV_START, NULL);
1295                         if (ret) {
1296                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1297                                          __func__, devfreq->governor->name,
1298                                          ret);
1299                         }
1300                 }
1301         }
1302
1303 err_out:
1304         mutex_unlock(&devfreq_list_lock);
1305
1306         return err;
1307 }
1308 EXPORT_SYMBOL(devfreq_add_governor);
1309
1310 static void devm_devfreq_remove_governor(void *governor)
1311 {
1312         WARN_ON(devfreq_remove_governor(governor));
1313 }
1314
1315 /**
1316  * devm_devfreq_add_governor() - Add devfreq governor
1317  * @dev:        device which adds devfreq governor
1318  * @governor:   the devfreq governor to be added
1319  *
1320  * This is a resource-managed variant of devfreq_add_governor().
1321  */
1322 int devm_devfreq_add_governor(struct device *dev,
1323                               struct devfreq_governor *governor)
1324 {
1325         int err;
1326
1327         err = devfreq_add_governor(governor);
1328         if (err)
1329                 return err;
1330
1331         return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
1332                                         governor);
1333 }
1334 EXPORT_SYMBOL(devm_devfreq_add_governor);
1335
1336 /**
1337  * devfreq_remove_governor() - Remove devfreq feature from a device.
1338  * @governor:   the devfreq governor to be removed
1339  */
1340 int devfreq_remove_governor(struct devfreq_governor *governor)
1341 {
1342         struct devfreq_governor *g;
1343         struct devfreq *devfreq;
1344         int err = 0;
1345
1346         if (!governor) {
1347                 pr_err("%s: Invalid parameters.\n", __func__);
1348                 return -EINVAL;
1349         }
1350
1351         mutex_lock(&devfreq_list_lock);
1352         g = find_devfreq_governor(governor->name);
1353         if (IS_ERR(g)) {
1354                 pr_err("%s: governor %s not registered\n", __func__,
1355                        governor->name);
1356                 err = PTR_ERR(g);
1357                 goto err_out;
1358         }
1359         list_for_each_entry(devfreq, &devfreq_list, node) {
1360                 int ret;
1361                 struct device *dev = devfreq->dev.parent;
1362
1363                 if (!strncmp(devfreq->governor->name, governor->name,
1364                              DEVFREQ_NAME_LEN)) {
1365                         /* we should have a devfreq governor! */
1366                         if (!devfreq->governor) {
1367                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1368                                          __func__, governor->name);
1369                                 continue;
1370                                 /* Fall through */
1371                         }
1372                         ret = devfreq->governor->event_handler(devfreq,
1373                                                 DEVFREQ_GOV_STOP, NULL);
1374                         if (ret) {
1375                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1376                                          __func__, devfreq->governor->name,
1377                                          ret);
1378                         }
1379                         devfreq->governor = NULL;
1380                 }
1381         }
1382
1383         list_del(&governor->node);
1384 err_out:
1385         mutex_unlock(&devfreq_list_lock);
1386
1387         return err;
1388 }
1389 EXPORT_SYMBOL(devfreq_remove_governor);
1390
1391 static ssize_t name_show(struct device *dev,
1392                         struct device_attribute *attr, char *buf)
1393 {
1394         struct devfreq *df = to_devfreq(dev);
1395         return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1396 }
1397 static DEVICE_ATTR_RO(name);
1398
1399 static ssize_t governor_show(struct device *dev,
1400                              struct device_attribute *attr, char *buf)
1401 {
1402         struct devfreq *df = to_devfreq(dev);
1403
1404         if (!df->governor)
1405                 return -EINVAL;
1406
1407         return sprintf(buf, "%s\n", df->governor->name);
1408 }
1409
1410 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1411                               const char *buf, size_t count)
1412 {
1413         struct devfreq *df = to_devfreq(dev);
1414         int ret;
1415         char str_governor[DEVFREQ_NAME_LEN + 1];
1416         const struct devfreq_governor *governor, *prev_governor;
1417
1418         if (!df->governor)
1419                 return -EINVAL;
1420
1421         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1422         if (ret != 1)
1423                 return -EINVAL;
1424
1425         mutex_lock(&devfreq_list_lock);
1426         governor = try_then_request_governor(str_governor);
1427         if (IS_ERR(governor)) {
1428                 ret = PTR_ERR(governor);
1429                 goto out;
1430         }
1431         if (df->governor == governor) {
1432                 ret = 0;
1433                 goto out;
1434         } else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
1435                 || IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
1436                 ret = -EINVAL;
1437                 goto out;
1438         }
1439
1440         /*
1441          * Stop the current governor and remove the specific sysfs files
1442          * which depend on current governor.
1443          */
1444         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1445         if (ret) {
1446                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1447                          __func__, df->governor->name, ret);
1448                 goto out;
1449         }
1450         remove_sysfs_files(df, df->governor);
1451
1452         /*
1453          * Start the new governor and create the specific sysfs files
1454          * which depend on the new governor.
1455          */
1456         prev_governor = df->governor;
1457         df->governor = governor;
1458         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1459         if (ret) {
1460                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1461                          __func__, df->governor->name, ret);
1462
1463                 /* Restore previous governor */
1464                 df->governor = prev_governor;
1465                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1466                 if (ret) {
1467                         dev_err(dev,
1468                                 "%s: reverting to Governor %s failed (%d)\n",
1469                                 __func__, prev_governor->name, ret);
1470                         df->governor = NULL;
1471                         goto out;
1472                 }
1473         }
1474
1475         /*
1476          * Create the sysfs files for the new governor. But if failed to start
1477          * the new governor, restore the sysfs files of previous governor.
1478          */
1479         create_sysfs_files(df, df->governor);
1480
1481 out:
1482         mutex_unlock(&devfreq_list_lock);
1483
1484         if (!ret)
1485                 ret = count;
1486         return ret;
1487 }
1488 static DEVICE_ATTR_RW(governor);
1489
1490 static ssize_t available_governors_show(struct device *d,
1491                                         struct device_attribute *attr,
1492                                         char *buf)
1493 {
1494         struct devfreq *df = to_devfreq(d);
1495         ssize_t count = 0;
1496
1497         if (!df->governor)
1498                 return -EINVAL;
1499
1500         mutex_lock(&devfreq_list_lock);
1501
1502         /*
1503          * The devfreq with immutable governor (e.g., passive) shows
1504          * only own governor.
1505          */
1506         if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
1507                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1508                                   "%s ", df->governor->name);
1509         /*
1510          * The devfreq device shows the registered governor except for
1511          * immutable governors such as passive governor .
1512          */
1513         } else {
1514                 struct devfreq_governor *governor;
1515
1516                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1517                         if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
1518                                 continue;
1519                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1520                                            "%s ", governor->name);
1521                 }
1522         }
1523
1524         mutex_unlock(&devfreq_list_lock);
1525
1526         /* Truncate the trailing space */
1527         if (count)
1528                 count--;
1529
1530         count += sprintf(&buf[count], "\n");
1531
1532         return count;
1533 }
1534 static DEVICE_ATTR_RO(available_governors);
1535
1536 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1537                              char *buf)
1538 {
1539         unsigned long freq;
1540         struct devfreq *df = to_devfreq(dev);
1541
1542         if (!df->profile)
1543                 return -EINVAL;
1544
1545         if (df->profile->get_cur_freq &&
1546                 !df->profile->get_cur_freq(df->dev.parent, &freq))
1547                 return sprintf(buf, "%lu\n", freq);
1548
1549         return sprintf(buf, "%lu\n", df->previous_freq);
1550 }
1551 static DEVICE_ATTR_RO(cur_freq);
1552
1553 static ssize_t target_freq_show(struct device *dev,
1554                                 struct device_attribute *attr, char *buf)
1555 {
1556         struct devfreq *df = to_devfreq(dev);
1557
1558         return sprintf(buf, "%lu\n", df->previous_freq);
1559 }
1560 static DEVICE_ATTR_RO(target_freq);
1561
1562 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1563                               const char *buf, size_t count)
1564 {
1565         struct devfreq *df = to_devfreq(dev);
1566         unsigned long value;
1567         int ret;
1568
1569         /*
1570          * Protect against theoretical sysfs writes between
1571          * device_add and dev_pm_qos_add_request
1572          */
1573         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1574                 return -EAGAIN;
1575
1576         ret = sscanf(buf, "%lu", &value);
1577         if (ret != 1)
1578                 return -EINVAL;
1579
1580         /* Round down to kHz for PM QoS */
1581         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1582                                         value / HZ_PER_KHZ);
1583         if (ret < 0)
1584                 return ret;
1585
1586         return count;
1587 }
1588
1589 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1590                              char *buf)
1591 {
1592         struct devfreq *df = to_devfreq(dev);
1593         unsigned long min_freq, max_freq;
1594
1595         mutex_lock(&df->lock);
1596         devfreq_get_freq_range(df, &min_freq, &max_freq);
1597         mutex_unlock(&df->lock);
1598
1599         return sprintf(buf, "%lu\n", min_freq);
1600 }
1601 static DEVICE_ATTR_RW(min_freq);
1602
1603 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1604                               const char *buf, size_t count)
1605 {
1606         struct devfreq *df = to_devfreq(dev);
1607         unsigned long value;
1608         int ret;
1609
1610         /*
1611          * Protect against theoretical sysfs writes between
1612          * device_add and dev_pm_qos_add_request
1613          */
1614         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1615                 return -EINVAL;
1616
1617         ret = sscanf(buf, "%lu", &value);
1618         if (ret != 1)
1619                 return -EINVAL;
1620
1621         /*
1622          * PM QoS frequencies are in kHz so we need to convert. Convert by
1623          * rounding upwards so that the acceptable interval never shrinks.
1624          *
1625          * For example if the user writes "666666666" to sysfs this value will
1626          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1627          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1628          *
1629          * A value of zero means "no limit".
1630          */
1631         if (value)
1632                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1633         else
1634                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1635
1636         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1637         if (ret < 0)
1638                 return ret;
1639
1640         return count;
1641 }
1642
1643 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1644                              char *buf)
1645 {
1646         struct devfreq *df = to_devfreq(dev);
1647         unsigned long min_freq, max_freq;
1648
1649         mutex_lock(&df->lock);
1650         devfreq_get_freq_range(df, &min_freq, &max_freq);
1651         mutex_unlock(&df->lock);
1652
1653         return sprintf(buf, "%lu\n", max_freq);
1654 }
1655 static DEVICE_ATTR_RW(max_freq);
1656
1657 static ssize_t available_frequencies_show(struct device *d,
1658                                           struct device_attribute *attr,
1659                                           char *buf)
1660 {
1661         struct devfreq *df = to_devfreq(d);
1662         ssize_t count = 0;
1663         int i;
1664
1665         if (!df->profile)
1666                 return -EINVAL;
1667
1668         mutex_lock(&df->lock);
1669
1670         for (i = 0; i < df->max_state; i++)
1671                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1672                                 "%lu ", df->freq_table[i]);
1673
1674         mutex_unlock(&df->lock);
1675         /* Truncate the trailing space */
1676         if (count)
1677                 count--;
1678
1679         count += sprintf(&buf[count], "\n");
1680
1681         return count;
1682 }
1683 static DEVICE_ATTR_RO(available_frequencies);
1684
1685 static ssize_t trans_stat_show(struct device *dev,
1686                                struct device_attribute *attr, char *buf)
1687 {
1688         struct devfreq *df = to_devfreq(dev);
1689         ssize_t len;
1690         int i, j;
1691         unsigned int max_state;
1692
1693         if (!df->profile)
1694                 return -EINVAL;
1695         max_state = df->max_state;
1696
1697         if (max_state == 0)
1698                 return sprintf(buf, "Not Supported.\n");
1699
1700         mutex_lock(&df->lock);
1701         if (!df->stop_polling &&
1702                         devfreq_update_status(df, df->previous_freq)) {
1703                 mutex_unlock(&df->lock);
1704                 return 0;
1705         }
1706         mutex_unlock(&df->lock);
1707
1708         len = sprintf(buf, "     From  :   To\n");
1709         len += sprintf(buf + len, "           :");
1710         for (i = 0; i < max_state; i++)
1711                 len += sprintf(buf + len, "%10lu",
1712                                 df->freq_table[i]);
1713
1714         len += sprintf(buf + len, "   time(ms)\n");
1715
1716         for (i = 0; i < max_state; i++) {
1717                 if (df->freq_table[i] == df->previous_freq)
1718                         len += sprintf(buf + len, "*");
1719                 else
1720                         len += sprintf(buf + len, " ");
1721
1722                 len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
1723                 for (j = 0; j < max_state; j++)
1724                         len += sprintf(buf + len, "%10u",
1725                                 df->stats.trans_table[(i * max_state) + j]);
1726
1727                 len += sprintf(buf + len, "%10llu\n", (u64)
1728                         jiffies64_to_msecs(df->stats.time_in_state[i]));
1729         }
1730
1731         len += sprintf(buf + len, "Total transition : %u\n",
1732                                         df->stats.total_trans);
1733         return len;
1734 }
1735
1736 static ssize_t trans_stat_store(struct device *dev,
1737                                 struct device_attribute *attr,
1738                                 const char *buf, size_t count)
1739 {
1740         struct devfreq *df = to_devfreq(dev);
1741         int err, value;
1742
1743         if (!df->profile)
1744                 return -EINVAL;
1745
1746         if (df->max_state == 0)
1747                 return count;
1748
1749         err = kstrtoint(buf, 10, &value);
1750         if (err || value != 0)
1751                 return -EINVAL;
1752
1753         mutex_lock(&df->lock);
1754         memset(df->stats.time_in_state, 0, (df->max_state *
1755                                         sizeof(*df->stats.time_in_state)));
1756         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1757                                         df->max_state,
1758                                         df->max_state));
1759         df->stats.total_trans = 0;
1760         df->stats.last_update = get_jiffies_64();
1761         mutex_unlock(&df->lock);
1762
1763         return count;
1764 }
1765 static DEVICE_ATTR_RW(trans_stat);
1766
1767 static struct attribute *devfreq_attrs[] = {
1768         &dev_attr_name.attr,
1769         &dev_attr_governor.attr,
1770         &dev_attr_available_governors.attr,
1771         &dev_attr_cur_freq.attr,
1772         &dev_attr_available_frequencies.attr,
1773         &dev_attr_target_freq.attr,
1774         &dev_attr_min_freq.attr,
1775         &dev_attr_max_freq.attr,
1776         &dev_attr_trans_stat.attr,
1777         NULL,
1778 };
1779 ATTRIBUTE_GROUPS(devfreq);
1780
1781 static ssize_t polling_interval_show(struct device *dev,
1782                                      struct device_attribute *attr, char *buf)
1783 {
1784         struct devfreq *df = to_devfreq(dev);
1785
1786         if (!df->profile)
1787                 return -EINVAL;
1788
1789         return sprintf(buf, "%d\n", df->profile->polling_ms);
1790 }
1791
1792 static ssize_t polling_interval_store(struct device *dev,
1793                                       struct device_attribute *attr,
1794                                       const char *buf, size_t count)
1795 {
1796         struct devfreq *df = to_devfreq(dev);
1797         unsigned int value;
1798         int ret;
1799
1800         if (!df->governor)
1801                 return -EINVAL;
1802
1803         ret = sscanf(buf, "%u", &value);
1804         if (ret != 1)
1805                 return -EINVAL;
1806
1807         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1808         ret = count;
1809
1810         return ret;
1811 }
1812 static DEVICE_ATTR_RW(polling_interval);
1813
1814 static ssize_t timer_show(struct device *dev,
1815                              struct device_attribute *attr, char *buf)
1816 {
1817         struct devfreq *df = to_devfreq(dev);
1818
1819         if (!df->profile)
1820                 return -EINVAL;
1821
1822         return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
1823 }
1824
1825 static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1826                               const char *buf, size_t count)
1827 {
1828         struct devfreq *df = to_devfreq(dev);
1829         char str_timer[DEVFREQ_NAME_LEN + 1];
1830         int timer = -1;
1831         int ret = 0, i;
1832
1833         if (!df->governor || !df->profile)
1834                 return -EINVAL;
1835
1836         ret = sscanf(buf, "%16s", str_timer);
1837         if (ret != 1)
1838                 return -EINVAL;
1839
1840         for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1841                 if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1842                         timer = i;
1843                         break;
1844                 }
1845         }
1846
1847         if (timer < 0) {
1848                 ret = -EINVAL;
1849                 goto out;
1850         }
1851
1852         if (df->profile->timer == timer) {
1853                 ret = 0;
1854                 goto out;
1855         }
1856
1857         mutex_lock(&df->lock);
1858         df->profile->timer = timer;
1859         mutex_unlock(&df->lock);
1860
1861         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1862         if (ret) {
1863                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1864                          __func__, df->governor->name, ret);
1865                 goto out;
1866         }
1867
1868         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1869         if (ret)
1870                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1871                          __func__, df->governor->name, ret);
1872 out:
1873         return ret ? ret : count;
1874 }
1875 static DEVICE_ATTR_RW(timer);
1876
1877 #define CREATE_SYSFS_FILE(df, name)                                     \
1878 {                                                                       \
1879         int ret;                                                        \
1880         ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);  \
1881         if (ret < 0) {                                                  \
1882                 dev_warn(&df->dev,                                      \
1883                         "Unable to create attr(%s)\n", "##name");       \
1884         }                                                               \
1885 }                                                                       \
1886
1887 /* Create the specific sysfs files which depend on each governor. */
1888 static void create_sysfs_files(struct devfreq *devfreq,
1889                                 const struct devfreq_governor *gov)
1890 {
1891         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1892                 CREATE_SYSFS_FILE(devfreq, polling_interval);
1893         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1894                 CREATE_SYSFS_FILE(devfreq, timer);
1895 }
1896
1897 /* Remove the specific sysfs files which depend on each governor. */
1898 static void remove_sysfs_files(struct devfreq *devfreq,
1899                                 const struct devfreq_governor *gov)
1900 {
1901         if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1902                 sysfs_remove_file(&devfreq->dev.kobj,
1903                                 &dev_attr_polling_interval.attr);
1904         if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1905                 sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
1906 }
1907
1908 /**
1909  * devfreq_summary_show() - Show the summary of the devfreq devices
1910  * @s:          seq_file instance to show the summary of devfreq devices
1911  * @data:       not used
1912  *
1913  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1914  * It helps that user can know the detailed information of the devfreq devices.
1915  *
1916  * Return 0 always because it shows the information without any data change.
1917  */
1918 static int devfreq_summary_show(struct seq_file *s, void *data)
1919 {
1920         struct devfreq *devfreq;
1921         struct devfreq *p_devfreq = NULL;
1922         unsigned long cur_freq, min_freq, max_freq;
1923         unsigned int polling_ms;
1924         unsigned int timer;
1925
1926         seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1927                         "dev",
1928                         "parent_dev",
1929                         "governor",
1930                         "timer",
1931                         "polling_ms",
1932                         "cur_freq_Hz",
1933                         "min_freq_Hz",
1934                         "max_freq_Hz");
1935         seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1936                         "------------------------------",
1937                         "------------------------------",
1938                         "---------------",
1939                         "----------",
1940                         "----------",
1941                         "------------",
1942                         "------------",
1943                         "------------");
1944
1945         mutex_lock(&devfreq_list_lock);
1946
1947         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1948 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1949                 if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
1950                                                         DEVFREQ_NAME_LEN)) {
1951                         struct devfreq_passive_data *data = devfreq->data;
1952
1953                         if (data)
1954                                 p_devfreq = data->parent;
1955                 } else {
1956                         p_devfreq = NULL;
1957                 }
1958 #endif
1959
1960                 mutex_lock(&devfreq->lock);
1961                 cur_freq = devfreq->previous_freq;
1962                 devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
1963                 timer = devfreq->profile->timer;
1964
1965                 if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
1966                         polling_ms = devfreq->profile->polling_ms;
1967                 else
1968                         polling_ms = 0;
1969                 mutex_unlock(&devfreq->lock);
1970
1971                 seq_printf(s,
1972                         "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
1973                         dev_name(&devfreq->dev),
1974                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1975                         devfreq->governor->name,
1976                         polling_ms ? timer_name[timer] : "null",
1977                         polling_ms,
1978                         cur_freq,
1979                         min_freq,
1980                         max_freq);
1981         }
1982
1983         mutex_unlock(&devfreq_list_lock);
1984
1985         return 0;
1986 }
1987 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1988
1989 static int __init devfreq_init(void)
1990 {
1991         devfreq_class = class_create("devfreq");
1992         if (IS_ERR(devfreq_class)) {
1993                 pr_err("%s: couldn't create class\n", __FILE__);
1994                 return PTR_ERR(devfreq_class);
1995         }
1996
1997         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1998         if (!devfreq_wq) {
1999                 class_destroy(devfreq_class);
2000                 pr_err("%s: couldn't create workqueue\n", __FILE__);
2001                 return -ENOMEM;
2002         }
2003         devfreq_class->dev_groups = devfreq_groups;
2004
2005         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
2006         debugfs_create_file("devfreq_summary", 0444,
2007                                 devfreq_debugfs, NULL,
2008                                 &devfreq_summary_fops);
2009
2010         return 0;
2011 }
2012 subsys_initcall(devfreq_init);
2013
2014 /*
2015  * The following are helper functions for devfreq user device drivers with
2016  * OPP framework.
2017  */
2018
2019 /**
2020  * devfreq_recommended_opp() - Helper function to get proper OPP for the
2021  *                           freq value given to target callback.
2022  * @dev:        The devfreq user device. (parent of devfreq)
2023  * @freq:       The frequency given to target function
2024  * @flags:      Flags handed from devfreq framework.
2025  *
2026  * The callers are required to call dev_pm_opp_put() for the returned OPP after
2027  * use.
2028  */
2029 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
2030                                            unsigned long *freq,
2031                                            u32 flags)
2032 {
2033         struct dev_pm_opp *opp;
2034
2035         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
2036                 /* The freq is an upper bound. opp should be lower */
2037                 opp = dev_pm_opp_find_freq_floor(dev, freq);
2038
2039                 /* If not available, use the closest opp */
2040                 if (opp == ERR_PTR(-ERANGE))
2041                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
2042         } else {
2043                 /* The freq is an lower bound. opp should be higher */
2044                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
2045
2046                 /* If not available, use the closest opp */
2047                 if (opp == ERR_PTR(-ERANGE))
2048                         opp = dev_pm_opp_find_freq_floor(dev, freq);
2049         }
2050
2051         return opp;
2052 }
2053 EXPORT_SYMBOL(devfreq_recommended_opp);
2054
2055 /**
2056  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
2057  *                                   for any changes in the OPP availability
2058  *                                   changes
2059  * @dev:        The devfreq user device. (parent of devfreq)
2060  * @devfreq:    The devfreq object.
2061  */
2062 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
2063 {
2064         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
2065 }
2066 EXPORT_SYMBOL(devfreq_register_opp_notifier);
2067
2068 /**
2069  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
2070  *                                     notified for any changes in the OPP
2071  *                                     availability changes anymore.
2072  * @dev:        The devfreq user device. (parent of devfreq)
2073  * @devfreq:    The devfreq object.
2074  *
2075  * At exit() callback of devfreq_dev_profile, this must be included if
2076  * devfreq_recommended_opp is used.
2077  */
2078 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
2079 {
2080         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
2081 }
2082 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
2083
2084 static void devm_devfreq_opp_release(struct device *dev, void *res)
2085 {
2086         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
2087 }
2088
2089 /**
2090  * devm_devfreq_register_opp_notifier() - Resource-managed
2091  *                                        devfreq_register_opp_notifier()
2092  * @dev:        The devfreq user device. (parent of devfreq)
2093  * @devfreq:    The devfreq object.
2094  */
2095 int devm_devfreq_register_opp_notifier(struct device *dev,
2096                                        struct devfreq *devfreq)
2097 {
2098         struct devfreq **ptr;
2099         int ret;
2100
2101         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
2102         if (!ptr)
2103                 return -ENOMEM;
2104
2105         ret = devfreq_register_opp_notifier(dev, devfreq);
2106         if (ret) {
2107                 devres_free(ptr);
2108                 return ret;
2109         }
2110
2111         *ptr = devfreq;
2112         devres_add(dev, ptr);
2113
2114         return 0;
2115 }
2116 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2117
2118 /**
2119  * devm_devfreq_unregister_opp_notifier() - Resource-managed
2120  *                                          devfreq_unregister_opp_notifier()
2121  * @dev:        The devfreq user device. (parent of devfreq)
2122  * @devfreq:    The devfreq object.
2123  */
2124 void devm_devfreq_unregister_opp_notifier(struct device *dev,
2125                                          struct devfreq *devfreq)
2126 {
2127         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2128                                devm_devfreq_dev_match, devfreq));
2129 }
2130 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2131
2132 /**
2133  * devfreq_register_notifier() - Register a driver with devfreq
2134  * @devfreq:    The devfreq object.
2135  * @nb:         The notifier block to register.
2136  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2137  */
2138 int devfreq_register_notifier(struct devfreq *devfreq,
2139                               struct notifier_block *nb,
2140                               unsigned int list)
2141 {
2142         int ret = 0;
2143
2144         if (!devfreq)
2145                 return -EINVAL;
2146
2147         switch (list) {
2148         case DEVFREQ_TRANSITION_NOTIFIER:
2149                 ret = srcu_notifier_chain_register(
2150                                 &devfreq->transition_notifier_list, nb);
2151                 break;
2152         default:
2153                 ret = -EINVAL;
2154         }
2155
2156         return ret;
2157 }
2158 EXPORT_SYMBOL(devfreq_register_notifier);
2159
2160 /*
2161  * devfreq_unregister_notifier() - Unregister a driver with devfreq
2162  * @devfreq:    The devfreq object.
2163  * @nb:         The notifier block to be unregistered.
2164  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2165  */
2166 int devfreq_unregister_notifier(struct devfreq *devfreq,
2167                                 struct notifier_block *nb,
2168                                 unsigned int list)
2169 {
2170         int ret = 0;
2171
2172         if (!devfreq)
2173                 return -EINVAL;
2174
2175         switch (list) {
2176         case DEVFREQ_TRANSITION_NOTIFIER:
2177                 ret = srcu_notifier_chain_unregister(
2178                                 &devfreq->transition_notifier_list, nb);
2179                 break;
2180         default:
2181                 ret = -EINVAL;
2182         }
2183
2184         return ret;
2185 }
2186 EXPORT_SYMBOL(devfreq_unregister_notifier);
2187
2188 struct devfreq_notifier_devres {
2189         struct devfreq *devfreq;
2190         struct notifier_block *nb;
2191         unsigned int list;
2192 };
2193
2194 static void devm_devfreq_notifier_release(struct device *dev, void *res)
2195 {
2196         struct devfreq_notifier_devres *this = res;
2197
2198         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2199 }
2200
2201 /**
2202  * devm_devfreq_register_notifier()
2203  *      - Resource-managed devfreq_register_notifier()
2204  * @dev:        The devfreq user device. (parent of devfreq)
2205  * @devfreq:    The devfreq object.
2206  * @nb:         The notifier block to be unregistered.
2207  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2208  */
2209 int devm_devfreq_register_notifier(struct device *dev,
2210                                 struct devfreq *devfreq,
2211                                 struct notifier_block *nb,
2212                                 unsigned int list)
2213 {
2214         struct devfreq_notifier_devres *ptr;
2215         int ret;
2216
2217         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2218                                 GFP_KERNEL);
2219         if (!ptr)
2220                 return -ENOMEM;
2221
2222         ret = devfreq_register_notifier(devfreq, nb, list);
2223         if (ret) {
2224                 devres_free(ptr);
2225                 return ret;
2226         }
2227
2228         ptr->devfreq = devfreq;
2229         ptr->nb = nb;
2230         ptr->list = list;
2231         devres_add(dev, ptr);
2232
2233         return 0;
2234 }
2235 EXPORT_SYMBOL(devm_devfreq_register_notifier);
2236
2237 /**
2238  * devm_devfreq_unregister_notifier()
2239  *      - Resource-managed devfreq_unregister_notifier()
2240  * @dev:        The devfreq user device. (parent of devfreq)
2241  * @devfreq:    The devfreq object.
2242  * @nb:         The notifier block to be unregistered.
2243  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2244  */
2245 void devm_devfreq_unregister_notifier(struct device *dev,
2246                                       struct devfreq *devfreq,
2247                                       struct notifier_block *nb,
2248                                       unsigned int list)
2249 {
2250         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2251                                devm_devfreq_dev_match, devfreq));
2252 }
2253 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);