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