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/errno.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/export.h>
  18 #include <linux/slab.h>
  19 #include <linux/stat.h>
  20 #include <linux/pm_opp.h>
  21 #include <linux/devfreq.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/list.h>
  25 #include <linux/printk.h>
  26 #include <linux/hrtimer.h>
  27 #include <linux/of.h>
  28 #include <linux/pm_qos.h>
  29 #include "governor.h"
  30
  31 #define CREATE_TRACE_POINTS
  32 #include <trace/events/devfreq.h>
  33
  34 #define HZ_PER_KHZ      1000
  35
  36 static struct class *devfreq_class;
  37 static struct dentry *devfreq_debugfs;
  38
  39 /*
  40  * devfreq core provides delayed work based load monitoring helper
  41  * functions. Governors can use these or can implement their own
  42  * monitoring mechanism.
  43  */
  44 static struct workqueue_struct *devfreq_wq;
  45
  46 /* The list of all device-devfreq governors */
  47 static LIST_HEAD(devfreq_governor_list);
  48 /* The list of all device-devfreq */
  49 static LIST_HEAD(devfreq_list);
  50 static DEFINE_MUTEX(devfreq_list_lock);
  51
  52 /**
  53  * find_device_devfreq() - find devfreq struct using device pointer
  54  * @dev:        device pointer used to lookup device devfreq.
  55  *
  56  * Search the list of device devfreqs and return the matched device's
  57  * devfreq info. devfreq_list_lock should be held by the caller.
  58  */
  59 static struct devfreq *find_device_devfreq(struct device *dev)
  60 {
  61         struct devfreq *tmp_devfreq;
  62
  63         lockdep_assert_held(&devfreq_list_lock);
  64
  65         if (IS_ERR_OR_NULL(dev)) {
  66                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  67                 return ERR_PTR(-EINVAL);
  68         }
  69
  70         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  71                 if (tmp_devfreq->dev.parent == dev)
  72                         return tmp_devfreq;
  73         }
  74
  75         return ERR_PTR(-ENODEV);
  76 }
  77
  78 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  79 {
  80         struct dev_pm_opp *opp;
  81         unsigned long min_freq = 0;
  82
  83         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  84         if (IS_ERR(opp))
  85                 min_freq = 0;
  86         else
  87                 dev_pm_opp_put(opp);
  88
  89         return min_freq;
  90 }
  91
  92 static unsigned long find_available_max_freq(struct devfreq *devfreq)
  93 {
  94         struct dev_pm_opp *opp;
  95         unsigned long max_freq = ULONG_MAX;
  96
  97         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
  98         if (IS_ERR(opp))
  99                 max_freq = 0;
 100         else
 101                 dev_pm_opp_put(opp);
 102
 103         return max_freq;
 104 }
 105
 106 /**
 107  * get_freq_range() - Get the current freq range
 108  * @devfreq:    the devfreq instance
 109  * @min_freq:   the min frequency
 110  * @max_freq:   the max frequency
 111  *
 112  * This takes into consideration all constraints.
 113  */
 114 static void get_freq_range(struct devfreq *devfreq,
 115                            unsigned long *min_freq,
 116                            unsigned long *max_freq)
 117 {
 118         unsigned long *freq_table = devfreq->profile->freq_table;
 119         s32 qos_min_freq, qos_max_freq;
 120
 121         lockdep_assert_held(&devfreq->lock);
 122
 123         /*
 124          * Initialize minimum/maximum frequency from freq table.
 125          * The devfreq drivers can initialize this in either ascending or
 126          * descending order and devfreq core supports both.
 127          */
 128         if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
 129                 *min_freq = freq_table[0];
 130                 *max_freq = freq_table[devfreq->profile->max_state - 1];
 131         } else {
 132                 *min_freq = freq_table[devfreq->profile->max_state - 1];
 133                 *max_freq = freq_table[0];
 134         }
 135
 136         /* Apply constraints from PM QoS */
 137         qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 138                                              DEV_PM_QOS_MIN_FREQUENCY);
 139         qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 140                                              DEV_PM_QOS_MAX_FREQUENCY);
 141         *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 142         if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 143                 *max_freq = min(*max_freq,
 144                                 (unsigned long)HZ_PER_KHZ * qos_max_freq);
 145
 146         /* Apply constraints from OPP interface */
 147         *min_freq = max(*min_freq, devfreq->scaling_min_freq);
 148         *max_freq = min(*max_freq, devfreq->scaling_max_freq);
 149
 150         if (*min_freq > *max_freq)
 151                 *min_freq = *max_freq;
 152 }
 153
 154 /**
 155  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 156  * @devfreq:    the devfreq instance
 157  * @freq:       the target frequency
 158  */
 159 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 160 {
 161         int lev;
 162
 163         for (lev = 0; lev < devfreq->profile->max_state; lev++)
 164                 if (freq == devfreq->profile->freq_table[lev])
 165                         return lev;
 166
 167         return -EINVAL;
 168 }
 169
 170 static int set_freq_table(struct devfreq *devfreq)
 171 {
 172         struct devfreq_dev_profile *profile = devfreq->profile;
 173         struct dev_pm_opp *opp;
 174         unsigned long freq;
 175         int i, count;
 176
 177         /* Initialize the freq_table from OPP table */
 178         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 179         if (count <= 0)
 180                 return -EINVAL;
 181
 182         profile->max_state = count;
 183         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 184                                         profile->max_state,
 185                                         sizeof(*profile->freq_table),
 186                                         GFP_KERNEL);
 187         if (!profile->freq_table) {
 188                 profile->max_state = 0;
 189                 return -ENOMEM;
 190         }
 191
 192         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 193                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 194                 if (IS_ERR(opp)) {
 195                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 196                         profile->max_state = 0;
 197                         return PTR_ERR(opp);
 198                 }
 199                 dev_pm_opp_put(opp);
 200                 profile->freq_table[i] = freq;
 201         }
 202
 203         return 0;
 204 }
 205
 206 /**
 207  * devfreq_update_status() - Update statistics of devfreq behavior
 208  * @devfreq:    the devfreq instance
 209  * @freq:       the update target frequency
 210  */
 211 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 212 {
 213         int lev, prev_lev, ret = 0;
 214         u64 cur_time;
 215
 216         lockdep_assert_held(&devfreq->lock);
 217         cur_time = get_jiffies_64();
 218
 219         /* Immediately exit if previous_freq is not initialized yet. */
 220         if (!devfreq->previous_freq)
 221                 goto out;
 222
 223         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 224         if (prev_lev < 0) {
 225                 ret = prev_lev;
 226                 goto out;
 227         }
 228
 229         devfreq->stats.time_in_state[prev_lev] +=
 230                         cur_time - devfreq->stats.last_update;
 231
 232         lev = devfreq_get_freq_level(devfreq, freq);
 233         if (lev < 0) {
 234                 ret = lev;
 235                 goto out;
 236         }
 237
 238         if (lev != prev_lev) {
 239                 devfreq->stats.trans_table[
 240                         (prev_lev * devfreq->profile->max_state) + lev]++;
 241                 devfreq->stats.total_trans++;
 242         }
 243
 244 out:
 245         devfreq->stats.last_update = cur_time;
 246         return ret;
 247 }
 248 EXPORT_SYMBOL(devfreq_update_status);
 249
 250 /**
 251  * find_devfreq_governor() - find devfreq governor from name
 252  * @name:       name of the governor
 253  *
 254  * Search the list of devfreq governors and return the matched
 255  * governor's pointer. devfreq_list_lock should be held by the caller.
 256  */
 257 static struct devfreq_governor *find_devfreq_governor(const char *name)
 258 {
 259         struct devfreq_governor *tmp_governor;
 260
 261         lockdep_assert_held(&devfreq_list_lock);
 262
 263         if (IS_ERR_OR_NULL(name)) {
 264                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 265                 return ERR_PTR(-EINVAL);
 266         }
 267
 268         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 269                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 270                         return tmp_governor;
 271         }
 272
 273         return ERR_PTR(-ENODEV);
 274 }
 275
 276 /**
 277  * try_then_request_governor() - Try to find the governor and request the
 278  *                               module if is not found.
 279  * @name:       name of the governor
 280  *
 281  * Search the list of devfreq governors and request the module and try again
 282  * if is not found. This can happen when both drivers (the governor driver
 283  * and the driver that call devfreq_add_device) are built as modules.
 284  * devfreq_list_lock should be held by the caller. Returns the matched
 285  * governor's pointer or an error pointer.
 286  */
 287 static struct devfreq_governor *try_then_request_governor(const char *name)
 288 {
 289         struct devfreq_governor *governor;
 290         int err = 0;
 291
 292         lockdep_assert_held(&devfreq_list_lock);
 293
 294         if (IS_ERR_OR_NULL(name)) {
 295                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 296                 return ERR_PTR(-EINVAL);
 297         }
 298
 299         governor = find_devfreq_governor(name);
 300         if (IS_ERR(governor)) {
 301                 mutex_unlock(&devfreq_list_lock);
 302
 303                 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 304                              DEVFREQ_NAME_LEN))
 305                         err = request_module("governor_%s", "simpleondemand");
 306                 else
 307                         err = request_module("governor_%s", name);
 308                 /* Restore previous state before return */
 309                 mutex_lock(&devfreq_list_lock);
 310                 if (err)
 311                         return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 312
 313                 governor = find_devfreq_governor(name);
 314         }
 315
 316         return governor;
 317 }
 318
 319 static int devfreq_notify_transition(struct devfreq *devfreq,
 320                 struct devfreq_freqs *freqs, unsigned int state)
 321 {
 322         if (!devfreq)
 323                 return -EINVAL;
 324
 325         switch (state) {
 326         case DEVFREQ_PRECHANGE:
 327                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 328                                 DEVFREQ_PRECHANGE, freqs);
 329                 break;
 330
 331         case DEVFREQ_POSTCHANGE:
 332                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 333                                 DEVFREQ_POSTCHANGE, freqs);
 334                 break;
 335         default:
 336                 return -EINVAL;
 337         }
 338
 339         return 0;
 340 }
 341
 342 static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 343                               u32 flags)
 344 {
 345         struct devfreq_freqs freqs;
 346         unsigned long cur_freq;
 347         int err = 0;
 348
 349         if (devfreq->profile->get_cur_freq)
 350                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 351         else
 352                 cur_freq = devfreq->previous_freq;
 353
 354         freqs.old = cur_freq;
 355         freqs.new = new_freq;
 356         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 357
 358         err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 359         if (err) {
 360                 freqs.new = cur_freq;
 361                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 362                 return err;
 363         }
 364
 365         freqs.new = new_freq;
 366         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 367
 368         if (devfreq_update_status(devfreq, new_freq))
 369                 dev_err(&devfreq->dev,
 370                         "Couldn't update frequency transition information.\n");
 371
 372         devfreq->previous_freq = new_freq;
 373
 374         if (devfreq->suspend_freq)
 375                 devfreq->resume_freq = cur_freq;
 376
 377         return err;
 378 }
 379
 380 /* Load monitoring helper functions for governors use */
 381
 382 /**
 383  * update_devfreq() - Reevaluate the device and configure frequency.
 384  * @devfreq:    the devfreq instance.
 385  *
 386  * Note: Lock devfreq->lock before calling update_devfreq
 387  *       This function is exported for governors.
 388  */
 389 int update_devfreq(struct devfreq *devfreq)
 390 {
 391         unsigned long freq, min_freq, max_freq;
 392         int err = 0;
 393         u32 flags = 0;
 394
 395         lockdep_assert_held(&devfreq->lock);
 396
 397         if (!devfreq->governor)
 398                 return -EINVAL;
 399
 400         /* Reevaluate the proper frequency */
 401         err = devfreq->governor->get_target_freq(devfreq, &freq);
 402         if (err)
 403                 return err;
 404         get_freq_range(devfreq, &min_freq, &max_freq);
 405
 406         if (freq < min_freq) {
 407                 freq = min_freq;
 408                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 409         }
 410         if (freq > max_freq) {
 411                 freq = max_freq;
 412                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 413         }
 414
 415         return devfreq_set_target(devfreq, freq, flags);
 416
 417 }
 418 EXPORT_SYMBOL(update_devfreq);
 419
 420 /**
 421  * devfreq_monitor() - Periodically poll devfreq objects.
 422  * @work:       the work struct used to run devfreq_monitor periodically.
 423  *
 424  */
 425 static void devfreq_monitor(struct work_struct *work)
 426 {
 427         int err;
 428         struct devfreq *devfreq = container_of(work,
 429                                         struct devfreq, work.work);
 430
 431         mutex_lock(&devfreq->lock);
 432         err = update_devfreq(devfreq);
 433         if (err)
 434                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 435
 436         queue_delayed_work(devfreq_wq, &devfreq->work,
 437                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 438         mutex_unlock(&devfreq->lock);
 439
 440         trace_devfreq_monitor(devfreq);
 441 }
 442
 443 /**
 444  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 445  * @devfreq:    the devfreq instance.
 446  *
 447  * Helper function for starting devfreq device load monitoring. By
 448  * default delayed work based monitoring is supported. Function
 449  * to be called from governor in response to DEVFREQ_GOV_START
 450  * event when device is added to devfreq framework.
 451  */
 452 void devfreq_monitor_start(struct devfreq *devfreq)
 453 {
 454         if (devfreq->governor->interrupt_driven)
 455                 return;
 456
 457         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 458         if (devfreq->profile->polling_ms)
 459                 queue_delayed_work(devfreq_wq, &devfreq->work,
 460                         msecs_to_jiffies(devfreq->profile->polling_ms));
 461 }
 462 EXPORT_SYMBOL(devfreq_monitor_start);
 463
 464 /**
 465  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 466  * @devfreq:    the devfreq instance.
 467  *
 468  * Helper function to stop devfreq device load monitoring. Function
 469  * to be called from governor in response to DEVFREQ_GOV_STOP
 470  * event when device is removed from devfreq framework.
 471  */
 472 void devfreq_monitor_stop(struct devfreq *devfreq)
 473 {
 474         if (devfreq->governor->interrupt_driven)
 475                 return;
 476
 477         cancel_delayed_work_sync(&devfreq->work);
 478 }
 479 EXPORT_SYMBOL(devfreq_monitor_stop);
 480
 481 /**
 482  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 483  * @devfreq:    the devfreq instance.
 484  *
 485  * Helper function to suspend devfreq device load monitoring. Function
 486  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 487  * event or when polling interval is set to zero.
 488  *
 489  * Note: Though this function is same as devfreq_monitor_stop(),
 490  * intentionally kept separate to provide hooks for collecting
 491  * transition statistics.
 492  */
 493 void devfreq_monitor_suspend(struct devfreq *devfreq)
 494 {
 495         mutex_lock(&devfreq->lock);
 496         if (devfreq->stop_polling) {
 497                 mutex_unlock(&devfreq->lock);
 498                 return;
 499         }
 500
 501         devfreq_update_status(devfreq, devfreq->previous_freq);
 502         devfreq->stop_polling = true;
 503         mutex_unlock(&devfreq->lock);
 504
 505         if (devfreq->governor->interrupt_driven)
 506                 return;
 507
 508         cancel_delayed_work_sync(&devfreq->work);
 509 }
 510 EXPORT_SYMBOL(devfreq_monitor_suspend);
 511
 512 /**
 513  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 514  * @devfreq:    the devfreq instance.
 515  *
 516  * Helper function to resume devfreq device load monitoring. Function
 517  * to be called from governor in response to DEVFREQ_GOV_RESUME
 518  * event or when polling interval is set to non-zero.
 519  */
 520 void devfreq_monitor_resume(struct devfreq *devfreq)
 521 {
 522         unsigned long freq;
 523
 524         mutex_lock(&devfreq->lock);
 525         if (!devfreq->stop_polling)
 526                 goto out;
 527
 528         if (devfreq->governor->interrupt_driven)
 529                 goto out_update;
 530
 531         if (!delayed_work_pending(&devfreq->work) &&
 532                         devfreq->profile->polling_ms)
 533                 queue_delayed_work(devfreq_wq, &devfreq->work,
 534                         msecs_to_jiffies(devfreq->profile->polling_ms));
 535
 536 out_update:
 537         devfreq->stats.last_update = get_jiffies_64();
 538         devfreq->stop_polling = false;
 539
 540         if (devfreq->profile->get_cur_freq &&
 541                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 542                 devfreq->previous_freq = freq;
 543
 544 out:
 545         mutex_unlock(&devfreq->lock);
 546 }
 547 EXPORT_SYMBOL(devfreq_monitor_resume);
 548
 549 /**
 550  * devfreq_update_interval() - Update device devfreq monitoring interval
 551  * @devfreq:    the devfreq instance.
 552  * @delay:      new polling interval to be set.
 553  *
 554  * Helper function to set new load monitoring polling interval. Function
 555  * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 556  */
 557 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 558 {
 559         unsigned int cur_delay = devfreq->profile->polling_ms;
 560         unsigned int new_delay = *delay;
 561
 562         mutex_lock(&devfreq->lock);
 563         devfreq->profile->polling_ms = new_delay;
 564
 565         if (devfreq->stop_polling)
 566                 goto out;
 567
 568         if (devfreq->governor->interrupt_driven)
 569                 goto out;
 570
 571         /* if new delay is zero, stop polling */
 572         if (!new_delay) {
 573                 mutex_unlock(&devfreq->lock);
 574                 cancel_delayed_work_sync(&devfreq->work);
 575                 return;
 576         }
 577
 578         /* if current delay is zero, start polling with new delay */
 579         if (!cur_delay) {
 580                 queue_delayed_work(devfreq_wq, &devfreq->work,
 581                         msecs_to_jiffies(devfreq->profile->polling_ms));
 582                 goto out;
 583         }
 584
 585         /* if current delay is greater than new delay, restart polling */
 586         if (cur_delay > new_delay) {
 587                 mutex_unlock(&devfreq->lock);
 588                 cancel_delayed_work_sync(&devfreq->work);
 589                 mutex_lock(&devfreq->lock);
 590                 if (!devfreq->stop_polling)
 591                         queue_delayed_work(devfreq_wq, &devfreq->work,
 592                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 593         }
 594 out:
 595         mutex_unlock(&devfreq->lock);
 596 }
 597 EXPORT_SYMBOL(devfreq_update_interval);
 598
 599 /**
 600  * devfreq_notifier_call() - Notify that the device frequency requirements
 601  *                           has been changed out of devfreq framework.
 602  * @nb:         the notifier_block (supposed to be devfreq->nb)
 603  * @type:       not used
 604  * @devp:       not used
 605  *
 606  * Called by a notifier that uses devfreq->nb.
 607  */
 608 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 609                                  void *devp)
 610 {
 611         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 612         int err = -EINVAL;
 613
 614         mutex_lock(&devfreq->lock);
 615
 616         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 617         if (!devfreq->scaling_min_freq)
 618                 goto out;
 619
 620         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 621         if (!devfreq->scaling_max_freq) {
 622                 devfreq->scaling_max_freq = ULONG_MAX;
 623                 goto out;
 624         }
 625
 626         err = update_devfreq(devfreq);
 627
 628 out:
 629         mutex_unlock(&devfreq->lock);
 630         if (err)
 631                 dev_err(devfreq->dev.parent,
 632                         "failed to update frequency from OPP notifier (%d)\n",
 633                         err);
 634
 635         return NOTIFY_OK;
 636 }
 637
 638 /**
 639  * qos_notifier_call() - Common handler for QoS constraints.
 640  * @devfreq:    the devfreq instance.
 641  */
 642 static int qos_notifier_call(struct devfreq *devfreq)
 643 {
 644         int err;
 645
 646         mutex_lock(&devfreq->lock);
 647         err = update_devfreq(devfreq);
 648         mutex_unlock(&devfreq->lock);
 649         if (err)
 650                 dev_err(devfreq->dev.parent,
 651                         "failed to update frequency from PM QoS (%d)\n",
 652                         err);
 653
 654         return NOTIFY_OK;
 655 }
 656
 657 /**
 658  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 659  * @nb:         Should be devfreq->nb_min
 660  */
 661 static int qos_min_notifier_call(struct notifier_block *nb,
 662                                          unsigned long val, void *ptr)
 663 {
 664         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 665 }
 666
 667 /**
 668  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 669  * @nb:         Should be devfreq->nb_max
 670  */
 671 static int qos_max_notifier_call(struct notifier_block *nb,
 672                                          unsigned long val, void *ptr)
 673 {
 674         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 675 }
 676
 677 /**
 678  * devfreq_dev_release() - Callback for struct device to release the device.
 679  * @dev:        the devfreq device
 680  *
 681  * Remove devfreq from the list and release its resources.
 682  */
 683 static void devfreq_dev_release(struct device *dev)
 684 {
 685         struct devfreq *devfreq = to_devfreq(dev);
 686         int err;
 687
 688         mutex_lock(&devfreq_list_lock);
 689         list_del(&devfreq->node);
 690         mutex_unlock(&devfreq_list_lock);
 691
 692         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 693                                          DEV_PM_QOS_MAX_FREQUENCY);
 694         if (err && err != -ENOENT)
 695                 dev_warn(dev->parent,
 696                         "Failed to remove max_freq notifier: %d\n", err);
 697         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 698                                          DEV_PM_QOS_MIN_FREQUENCY);
 699         if (err && err != -ENOENT)
 700                 dev_warn(dev->parent,
 701                         "Failed to remove min_freq notifier: %d\n", err);
 702
 703         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 704                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 705                 if (err < 0)
 706                         dev_warn(dev->parent,
 707                                 "Failed to remove max_freq request: %d\n", err);
 708         }
 709         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 710                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 711                 if (err < 0)
 712                         dev_warn(dev->parent,
 713                                 "Failed to remove min_freq request: %d\n", err);
 714         }
 715
 716         if (devfreq->profile->exit)
 717                 devfreq->profile->exit(devfreq->dev.parent);
 718
 719         mutex_destroy(&devfreq->lock);
 720         kfree(devfreq);
 721 }
 722
 723 /**
 724  * devfreq_add_device() - Add devfreq feature to the device
 725  * @dev:        the device to add devfreq feature.
 726  * @profile:    device-specific profile to run devfreq.
 727  * @governor_name:      name of the policy to choose frequency.
 728  * @data:       private data for the governor. The devfreq framework does not
 729  *              touch this value.
 730  */
 731 struct devfreq *devfreq_add_device(struct device *dev,
 732                                    struct devfreq_dev_profile *profile,
 733                                    const char *governor_name,
 734                                    void *data)
 735 {
 736         struct devfreq *devfreq;
 737         struct devfreq_governor *governor;
 738         int err = 0;
 739
 740         if (!dev || !profile || !governor_name) {
 741                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 742                 return ERR_PTR(-EINVAL);
 743         }
 744
 745         mutex_lock(&devfreq_list_lock);
 746         devfreq = find_device_devfreq(dev);
 747         mutex_unlock(&devfreq_list_lock);
 748         if (!IS_ERR(devfreq)) {
 749                 dev_err(dev, "%s: devfreq device already exists!\n",
 750                         __func__);
 751                 err = -EINVAL;
 752                 goto err_out;
 753         }
 754
 755         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 756         if (!devfreq) {
 757                 err = -ENOMEM;
 758                 goto err_out;
 759         }
 760
 761         mutex_init(&devfreq->lock);
 762         mutex_lock(&devfreq->lock);
 763         devfreq->dev.parent = dev;
 764         devfreq->dev.class = devfreq_class;
 765         devfreq->dev.release = devfreq_dev_release;
 766         INIT_LIST_HEAD(&devfreq->node);
 767         devfreq->profile = profile;
 768         strscpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 769         devfreq->previous_freq = profile->initial_freq;
 770         devfreq->last_status.current_frequency = profile->initial_freq;
 771         devfreq->data = data;
 772         devfreq->nb.notifier_call = devfreq_notifier_call;
 773
 774         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 775                 mutex_unlock(&devfreq->lock);
 776                 err = set_freq_table(devfreq);
 777                 if (err < 0)
 778                         goto err_dev;
 779                 mutex_lock(&devfreq->lock);
 780         }
 781
 782         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 783         if (!devfreq->scaling_min_freq) {
 784                 mutex_unlock(&devfreq->lock);
 785                 err = -EINVAL;
 786                 goto err_dev;
 787         }
 788
 789         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 790         if (!devfreq->scaling_max_freq) {
 791                 mutex_unlock(&devfreq->lock);
 792                 err = -EINVAL;
 793                 goto err_dev;
 794         }
 795
 796         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 797         atomic_set(&devfreq->suspend_count, 0);
 798
 799         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 800         err = device_register(&devfreq->dev);
 801         if (err) {
 802                 mutex_unlock(&devfreq->lock);
 803                 put_device(&devfreq->dev);
 804                 goto err_out;
 805         }
 806
 807         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 808                         array3_size(sizeof(unsigned int),
 809                                     devfreq->profile->max_state,
 810                                     devfreq->profile->max_state),
 811                         GFP_KERNEL);
 812         if (!devfreq->stats.trans_table) {
 813                 mutex_unlock(&devfreq->lock);
 814                 err = -ENOMEM;
 815                 goto err_devfreq;
 816         }
 817
 818         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 819                         devfreq->profile->max_state,
 820                         sizeof(*devfreq->stats.time_in_state),
 821                         GFP_KERNEL);
 822         if (!devfreq->stats.time_in_state) {
 823                 mutex_unlock(&devfreq->lock);
 824                 err = -ENOMEM;
 825                 goto err_devfreq;
 826         }
 827
 828         devfreq->stats.total_trans = 0;
 829         devfreq->stats.last_update = get_jiffies_64();
 830
 831         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 832
 833         mutex_unlock(&devfreq->lock);
 834
 835         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 836                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 837         if (err < 0)
 838                 goto err_devfreq;
 839         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 840                                      DEV_PM_QOS_MAX_FREQUENCY,
 841                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 842         if (err < 0)
 843                 goto err_devfreq;
 844
 845         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 846         err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min,
 847                                       DEV_PM_QOS_MIN_FREQUENCY);
 848         if (err)
 849                 goto err_devfreq;
 850
 851         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 852         err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,
 853                                       DEV_PM_QOS_MAX_FREQUENCY);
 854         if (err)
 855                 goto err_devfreq;
 856
 857         mutex_lock(&devfreq_list_lock);
 858
 859         governor = try_then_request_governor(devfreq->governor_name);
 860         if (IS_ERR(governor)) {
 861                 dev_err(dev, "%s: Unable to find governor for the device\n",
 862                         __func__);
 863                 err = PTR_ERR(governor);
 864                 goto err_init;
 865         }
 866
 867         devfreq->governor = governor;
 868         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 869                                                 NULL);
 870         if (err) {
 871                 dev_err(dev, "%s: Unable to start governor for the device\n",
 872                         __func__);
 873                 goto err_init;
 874         }
 875
 876         list_add(&devfreq->node, &devfreq_list);
 877
 878         mutex_unlock(&devfreq_list_lock);
 879
 880         return devfreq;
 881
 882 err_init:
 883         mutex_unlock(&devfreq_list_lock);
 884 err_devfreq:
 885         devfreq_remove_device(devfreq);
 886         devfreq = NULL;
 887 err_dev:
 888         kfree(devfreq);
 889 err_out:
 890         return ERR_PTR(err);
 891 }
 892 EXPORT_SYMBOL(devfreq_add_device);
 893
 894 /**
 895  * devfreq_remove_device() - Remove devfreq feature from a device.
 896  * @devfreq:    the devfreq instance to be removed
 897  *
 898  * The opposite of devfreq_add_device().
 899  */
 900 int devfreq_remove_device(struct devfreq *devfreq)
 901 {
 902         if (!devfreq)
 903                 return -EINVAL;
 904
 905         if (devfreq->governor)
 906                 devfreq->governor->event_handler(devfreq,
 907                                                  DEVFREQ_GOV_STOP, NULL);
 908         device_unregister(&devfreq->dev);
 909
 910         return 0;
 911 }
 912 EXPORT_SYMBOL(devfreq_remove_device);
 913
 914 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 915 {
 916         struct devfreq **r = res;
 917
 918         if (WARN_ON(!r || !*r))
 919                 return 0;
 920
 921         return *r == data;
 922 }
 923
 924 static void devm_devfreq_dev_release(struct device *dev, void *res)
 925 {
 926         devfreq_remove_device(*(struct devfreq **)res);
 927 }
 928
 929 /**
 930  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 931  * @dev:        the device to add devfreq feature.
 932  * @profile:    device-specific profile to run devfreq.
 933  * @governor_name:      name of the policy to choose frequency.
 934  * @data:       private data for the governor. The devfreq framework does not
 935  *              touch this value.
 936  *
 937  * This function manages automatically the memory of devfreq device using device
 938  * resource management and simplify the free operation for memory of devfreq
 939  * device.
 940  */
 941 struct devfreq *devm_devfreq_add_device(struct device *dev,
 942                                         struct devfreq_dev_profile *profile,
 943                                         const char *governor_name,
 944                                         void *data)
 945 {
 946         struct devfreq **ptr, *devfreq;
 947
 948         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 949         if (!ptr)
 950                 return ERR_PTR(-ENOMEM);
 951
 952         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 953         if (IS_ERR(devfreq)) {
 954                 devres_free(ptr);
 955                 return devfreq;
 956         }
 957
 958         *ptr = devfreq;
 959         devres_add(dev, ptr);
 960
 961         return devfreq;
 962 }
 963 EXPORT_SYMBOL(devm_devfreq_add_device);
 964
 965 #ifdef CONFIG_OF
 966 /*
 967  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 968  * @dev - instance to the given device
 969  * @index - index into list of devfreq
 970  *
 971  * return the instance of devfreq device
 972  */
 973 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 974 {
 975         struct device_node *node;
 976         struct devfreq *devfreq;
 977
 978         if (!dev)
 979                 return ERR_PTR(-EINVAL);
 980
 981         if (!dev->of_node)
 982                 return ERR_PTR(-EINVAL);
 983
 984         node = of_parse_phandle(dev->of_node, "devfreq", index);
 985         if (!node)
 986                 return ERR_PTR(-ENODEV);
 987
 988         mutex_lock(&devfreq_list_lock);
 989         list_for_each_entry(devfreq, &devfreq_list, node) {
 990                 if (devfreq->dev.parent
 991                         && devfreq->dev.parent->of_node == node) {
 992                         mutex_unlock(&devfreq_list_lock);
 993                         of_node_put(node);
 994                         return devfreq;
 995                 }
 996         }
 997         mutex_unlock(&devfreq_list_lock);
 998         of_node_put(node);
 999
1000         return ERR_PTR(-EPROBE_DEFER);
1001 }
1002 #else
1003 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
1004 {
1005         return ERR_PTR(-ENODEV);
1006 }
1007 #endif /* CONFIG_OF */
1008 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1009
1010 /**
1011  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1012  * @dev:        the device from which to remove devfreq feature.
1013  * @devfreq:    the devfreq instance to be removed
1014  */
1015 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1016 {
1017         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1018                                devm_devfreq_dev_match, devfreq));
1019 }
1020 EXPORT_SYMBOL(devm_devfreq_remove_device);
1021
1022 /**
1023  * devfreq_suspend_device() - Suspend devfreq of a device.
1024  * @devfreq: the devfreq instance to be suspended
1025  *
1026  * This function is intended to be called by the pm callbacks
1027  * (e.g., runtime_suspend, suspend) of the device driver that
1028  * holds the devfreq.
1029  */
1030 int devfreq_suspend_device(struct devfreq *devfreq)
1031 {
1032         int ret;
1033
1034         if (!devfreq)
1035                 return -EINVAL;
1036
1037         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1038                 return 0;
1039
1040         if (devfreq->governor) {
1041                 ret = devfreq->governor->event_handler(devfreq,
1042                                         DEVFREQ_GOV_SUSPEND, NULL);
1043                 if (ret)
1044                         return ret;
1045         }
1046
1047         if (devfreq->suspend_freq) {
1048                 mutex_lock(&devfreq->lock);
1049                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1050                 mutex_unlock(&devfreq->lock);
1051                 if (ret)
1052                         return ret;
1053         }
1054
1055         return 0;
1056 }
1057 EXPORT_SYMBOL(devfreq_suspend_device);
1058
1059 /**
1060  * devfreq_resume_device() - Resume devfreq of a device.
1061  * @devfreq: the devfreq instance to be resumed
1062  *
1063  * This function is intended to be called by the pm callbacks
1064  * (e.g., runtime_resume, resume) of the device driver that
1065  * holds the devfreq.
1066  */
1067 int devfreq_resume_device(struct devfreq *devfreq)
1068 {
1069         int ret;
1070
1071         if (!devfreq)
1072                 return -EINVAL;
1073
1074         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1075                 return 0;
1076
1077         if (devfreq->resume_freq) {
1078                 mutex_lock(&devfreq->lock);
1079                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1080                 mutex_unlock(&devfreq->lock);
1081                 if (ret)
1082                         return ret;
1083         }
1084
1085         if (devfreq->governor) {
1086                 ret = devfreq->governor->event_handler(devfreq,
1087                                         DEVFREQ_GOV_RESUME, NULL);
1088                 if (ret)
1089                         return ret;
1090         }
1091
1092         return 0;
1093 }
1094 EXPORT_SYMBOL(devfreq_resume_device);
1095
1096 /**
1097  * devfreq_suspend() - Suspend devfreq governors and devices
1098  *
1099  * Called during system wide Suspend/Hibernate cycles for suspending governors
1100  * and devices preserving the state for resume. On some platforms the devfreq
1101  * device must have precise state (frequency) after resume in order to provide
1102  * fully operating setup.
1103  */
1104 void devfreq_suspend(void)
1105 {
1106         struct devfreq *devfreq;
1107         int ret;
1108
1109         mutex_lock(&devfreq_list_lock);
1110         list_for_each_entry(devfreq, &devfreq_list, node) {
1111                 ret = devfreq_suspend_device(devfreq);
1112                 if (ret)
1113                         dev_err(&devfreq->dev,
1114                                 "failed to suspend devfreq device\n");
1115         }
1116         mutex_unlock(&devfreq_list_lock);
1117 }
1118
1119 /**
1120  * devfreq_resume() - Resume devfreq governors and devices
1121  *
1122  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1123  * devices that are suspended with devfreq_suspend().
1124  */
1125 void devfreq_resume(void)
1126 {
1127         struct devfreq *devfreq;
1128         int ret;
1129
1130         mutex_lock(&devfreq_list_lock);
1131         list_for_each_entry(devfreq, &devfreq_list, node) {
1132                 ret = devfreq_resume_device(devfreq);
1133                 if (ret)
1134                         dev_warn(&devfreq->dev,
1135                                  "failed to resume devfreq device\n");
1136         }
1137         mutex_unlock(&devfreq_list_lock);
1138 }
1139
1140 /**
1141  * devfreq_add_governor() - Add devfreq governor
1142  * @governor:   the devfreq governor to be added
1143  */
1144 int devfreq_add_governor(struct devfreq_governor *governor)
1145 {
1146         struct devfreq_governor *g;
1147         struct devfreq *devfreq;
1148         int err = 0;
1149
1150         if (!governor) {
1151                 pr_err("%s: Invalid parameters.\n", __func__);
1152                 return -EINVAL;
1153         }
1154
1155         mutex_lock(&devfreq_list_lock);
1156         g = find_devfreq_governor(governor->name);
1157         if (!IS_ERR(g)) {
1158                 pr_err("%s: governor %s already registered\n", __func__,
1159                        g->name);
1160                 err = -EINVAL;
1161                 goto err_out;
1162         }
1163
1164         list_add(&governor->node, &devfreq_governor_list);
1165
1166         list_for_each_entry(devfreq, &devfreq_list, node) {
1167                 int ret = 0;
1168                 struct device *dev = devfreq->dev.parent;
1169
1170                 if (!strncmp(devfreq->governor_name, governor->name,
1171                              DEVFREQ_NAME_LEN)) {
1172                         /* The following should never occur */
1173                         if (devfreq->governor) {
1174                                 dev_warn(dev,
1175                                          "%s: Governor %s already present\n",
1176                                          __func__, devfreq->governor->name);
1177                                 ret = devfreq->governor->event_handler(devfreq,
1178                                                         DEVFREQ_GOV_STOP, NULL);
1179                                 if (ret) {
1180                                         dev_warn(dev,
1181                                                  "%s: Governor %s stop = %d\n",
1182                                                  __func__,
1183                                                  devfreq->governor->name, ret);
1184                                 }
1185                                 /* Fall through */
1186                         }
1187                         devfreq->governor = governor;
1188                         ret = devfreq->governor->event_handler(devfreq,
1189                                                 DEVFREQ_GOV_START, NULL);
1190                         if (ret) {
1191                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1192                                          __func__, devfreq->governor->name,
1193                                          ret);
1194                         }
1195                 }
1196         }
1197
1198 err_out:
1199         mutex_unlock(&devfreq_list_lock);
1200
1201         return err;
1202 }
1203 EXPORT_SYMBOL(devfreq_add_governor);
1204
1205 /**
1206  * devfreq_remove_governor() - Remove devfreq feature from a device.
1207  * @governor:   the devfreq governor to be removed
1208  */
1209 int devfreq_remove_governor(struct devfreq_governor *governor)
1210 {
1211         struct devfreq_governor *g;
1212         struct devfreq *devfreq;
1213         int err = 0;
1214
1215         if (!governor) {
1216                 pr_err("%s: Invalid parameters.\n", __func__);
1217                 return -EINVAL;
1218         }
1219
1220         mutex_lock(&devfreq_list_lock);
1221         g = find_devfreq_governor(governor->name);
1222         if (IS_ERR(g)) {
1223                 pr_err("%s: governor %s not registered\n", __func__,
1224                        governor->name);
1225                 err = PTR_ERR(g);
1226                 goto err_out;
1227         }
1228         list_for_each_entry(devfreq, &devfreq_list, node) {
1229                 int ret;
1230                 struct device *dev = devfreq->dev.parent;
1231
1232                 if (!strncmp(devfreq->governor_name, governor->name,
1233                              DEVFREQ_NAME_LEN)) {
1234                         /* we should have a devfreq governor! */
1235                         if (!devfreq->governor) {
1236                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1237                                          __func__, governor->name);
1238                                 continue;
1239                                 /* Fall through */
1240                         }
1241                         ret = devfreq->governor->event_handler(devfreq,
1242                                                 DEVFREQ_GOV_STOP, NULL);
1243                         if (ret) {
1244                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1245                                          __func__, devfreq->governor->name,
1246                                          ret);
1247                         }
1248                         devfreq->governor = NULL;
1249                 }
1250         }
1251
1252         list_del(&governor->node);
1253 err_out:
1254         mutex_unlock(&devfreq_list_lock);
1255
1256         return err;
1257 }
1258 EXPORT_SYMBOL(devfreq_remove_governor);
1259
1260 static ssize_t name_show(struct device *dev,
1261                         struct device_attribute *attr, char *buf)
1262 {
1263         struct devfreq *devfreq = to_devfreq(dev);
1264         return sprintf(buf, "%s\n", dev_name(devfreq->dev.parent));
1265 }
1266 static DEVICE_ATTR_RO(name);
1267
1268 static ssize_t governor_show(struct device *dev,
1269                              struct device_attribute *attr, char *buf)
1270 {
1271         if (!to_devfreq(dev)->governor)
1272                 return -EINVAL;
1273
1274         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
1275 }
1276
1277 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1278                               const char *buf, size_t count)
1279 {
1280         struct devfreq *df = to_devfreq(dev);
1281         int ret;
1282         char str_governor[DEVFREQ_NAME_LEN + 1];
1283         const struct devfreq_governor *governor, *prev_governor;
1284
1285         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1286         if (ret != 1)
1287                 return -EINVAL;
1288
1289         mutex_lock(&devfreq_list_lock);
1290         governor = try_then_request_governor(str_governor);
1291         if (IS_ERR(governor)) {
1292                 ret = PTR_ERR(governor);
1293                 goto out;
1294         }
1295         if (df->governor == governor) {
1296                 ret = 0;
1297                 goto out;
1298         } else if ((df->governor && df->governor->immutable) ||
1299                                         governor->immutable) {
1300                 ret = -EINVAL;
1301                 goto out;
1302         }
1303
1304         if (df->governor) {
1305                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1306                 if (ret) {
1307                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1308                                  __func__, df->governor->name, ret);
1309                         goto out;
1310                 }
1311         }
1312         prev_governor = df->governor;
1313         df->governor = governor;
1314         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1315         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1316         if (ret) {
1317                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1318                          __func__, df->governor->name, ret);
1319                 df->governor = prev_governor;
1320                 strncpy(df->governor_name, prev_governor->name,
1321                         DEVFREQ_NAME_LEN);
1322                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1323                 if (ret) {
1324                         dev_err(dev,
1325                                 "%s: reverting to Governor %s failed (%d)\n",
1326                                 __func__, df->governor_name, ret);
1327                         df->governor = NULL;
1328                 }
1329         }
1330 out:
1331         mutex_unlock(&devfreq_list_lock);
1332
1333         if (!ret)
1334                 ret = count;
1335         return ret;
1336 }
1337 static DEVICE_ATTR_RW(governor);
1338
1339 static ssize_t available_governors_show(struct device *d,
1340                                         struct device_attribute *attr,
1341                                         char *buf)
1342 {
1343         struct devfreq *df = to_devfreq(d);
1344         ssize_t count = 0;
1345
1346         mutex_lock(&devfreq_list_lock);
1347
1348         /*
1349          * The devfreq with immutable governor (e.g., passive) shows
1350          * only own governor.
1351          */
1352         if (df->governor && df->governor->immutable) {
1353                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1354                                   "%s ", df->governor_name);
1355         /*
1356          * The devfreq device shows the registered governor except for
1357          * immutable governors such as passive governor .
1358          */
1359         } else {
1360                 struct devfreq_governor *governor;
1361
1362                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1363                         if (governor->immutable)
1364                                 continue;
1365                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1366                                            "%s ", governor->name);
1367                 }
1368         }
1369
1370         mutex_unlock(&devfreq_list_lock);
1371
1372         /* Truncate the trailing space */
1373         if (count)
1374                 count--;
1375
1376         count += sprintf(&buf[count], "\n");
1377
1378         return count;
1379 }
1380 static DEVICE_ATTR_RO(available_governors);
1381
1382 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1383                              char *buf)
1384 {
1385         unsigned long freq;
1386         struct devfreq *devfreq = to_devfreq(dev);
1387
1388         if (devfreq->profile->get_cur_freq &&
1389                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1390                 return sprintf(buf, "%lu\n", freq);
1391
1392         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1393 }
1394 static DEVICE_ATTR_RO(cur_freq);
1395
1396 static ssize_t target_freq_show(struct device *dev,
1397                                 struct device_attribute *attr, char *buf)
1398 {
1399         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1400 }
1401 static DEVICE_ATTR_RO(target_freq);
1402
1403 static ssize_t polling_interval_show(struct device *dev,
1404                                      struct device_attribute *attr, char *buf)
1405 {
1406         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1407 }
1408
1409 static ssize_t polling_interval_store(struct device *dev,
1410                                       struct device_attribute *attr,
1411                                       const char *buf, size_t count)
1412 {
1413         struct devfreq *df = to_devfreq(dev);
1414         unsigned int value;
1415         int ret;
1416
1417         if (!df->governor)
1418                 return -EINVAL;
1419
1420         ret = sscanf(buf, "%u", &value);
1421         if (ret != 1)
1422                 return -EINVAL;
1423
1424         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1425         ret = count;
1426
1427         return ret;
1428 }
1429 static DEVICE_ATTR_RW(polling_interval);
1430
1431 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1432                               const char *buf, size_t count)
1433 {
1434         struct devfreq *df = to_devfreq(dev);
1435         unsigned long value;
1436         int ret;
1437
1438         /*
1439          * Protect against theoretical sysfs writes between
1440          * device_add and dev_pm_qos_add_request
1441          */
1442         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1443                 return -EAGAIN;
1444
1445         ret = sscanf(buf, "%lu", &value);
1446         if (ret != 1)
1447                 return -EINVAL;
1448
1449         /* Round down to kHz for PM QoS */
1450         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1451                                         value / HZ_PER_KHZ);
1452         if (ret < 0)
1453                 return ret;
1454
1455         return count;
1456 }
1457
1458 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1459                              char *buf)
1460 {
1461         struct devfreq *df = to_devfreq(dev);
1462         unsigned long min_freq, max_freq;
1463
1464         mutex_lock(&df->lock);
1465         get_freq_range(df, &min_freq, &max_freq);
1466         mutex_unlock(&df->lock);
1467
1468         return sprintf(buf, "%lu\n", min_freq);
1469 }
1470 static DEVICE_ATTR_RW(min_freq);
1471
1472 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1473                               const char *buf, size_t count)
1474 {
1475         struct devfreq *df = to_devfreq(dev);
1476         unsigned long value;
1477         int ret;
1478
1479         /*
1480          * Protect against theoretical sysfs writes between
1481          * device_add and dev_pm_qos_add_request
1482          */
1483         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1484                 return -EINVAL;
1485
1486         ret = sscanf(buf, "%lu", &value);
1487         if (ret != 1)
1488                 return -EINVAL;
1489
1490         /*
1491          * PM QoS frequencies are in kHz so we need to convert. Convert by
1492          * rounding upwards so that the acceptable interval never shrinks.
1493          *
1494          * For example if the user writes "666666666" to sysfs this value will
1495          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1496          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1497          *
1498          * A value of zero means "no limit".
1499          */
1500         if (value)
1501                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1502         else
1503                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1504
1505         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1506         if (ret < 0)
1507                 return ret;
1508
1509         return count;
1510 }
1511
1512 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1513                              char *buf)
1514 {
1515         struct devfreq *df = to_devfreq(dev);
1516         unsigned long min_freq, max_freq;
1517
1518         mutex_lock(&df->lock);
1519         get_freq_range(df, &min_freq, &max_freq);
1520         mutex_unlock(&df->lock);
1521
1522         return sprintf(buf, "%lu\n", max_freq);
1523 }
1524 static DEVICE_ATTR_RW(max_freq);
1525
1526 static ssize_t available_frequencies_show(struct device *d,
1527                                           struct device_attribute *attr,
1528                                           char *buf)
1529 {
1530         struct devfreq *df = to_devfreq(d);
1531         ssize_t count = 0;
1532         int i;
1533
1534         mutex_lock(&df->lock);
1535
1536         for (i = 0; i < df->profile->max_state; i++)
1537                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1538                                 "%lu ", df->profile->freq_table[i]);
1539
1540         mutex_unlock(&df->lock);
1541         /* Truncate the trailing space */
1542         if (count)
1543                 count--;
1544
1545         count += sprintf(&buf[count], "\n");
1546
1547         return count;
1548 }
1549 static DEVICE_ATTR_RO(available_frequencies);
1550
1551 static ssize_t trans_stat_show(struct device *dev,
1552                                struct device_attribute *attr, char *buf)
1553 {
1554         struct devfreq *devfreq = to_devfreq(dev);
1555         ssize_t len;
1556         int i, j;
1557         unsigned int max_state = devfreq->profile->max_state;
1558
1559         if (max_state == 0)
1560                 return sprintf(buf, "Not Supported.\n");
1561
1562         mutex_lock(&devfreq->lock);
1563         if (!devfreq->stop_polling &&
1564                         devfreq_update_status(devfreq, devfreq->previous_freq)) {
1565                 mutex_unlock(&devfreq->lock);
1566                 return 0;
1567         }
1568         mutex_unlock(&devfreq->lock);
1569
1570         len = sprintf(buf, "     From  :   To\n");
1571         len += sprintf(buf + len, "           :");
1572         for (i = 0; i < max_state; i++)
1573                 len += sprintf(buf + len, "%10lu",
1574                                 devfreq->profile->freq_table[i]);
1575
1576         len += sprintf(buf + len, "   time(ms)\n");
1577
1578         for (i = 0; i < max_state; i++) {
1579                 if (devfreq->profile->freq_table[i]
1580                                         == devfreq->previous_freq) {
1581                         len += sprintf(buf + len, "*");
1582                 } else {
1583                         len += sprintf(buf + len, " ");
1584                 }
1585                 len += sprintf(buf + len, "%10lu:",
1586                                 devfreq->profile->freq_table[i]);
1587                 for (j = 0; j < max_state; j++)
1588                         len += sprintf(buf + len, "%10u",
1589                                 devfreq->stats.trans_table[(i * max_state) + j]);
1590
1591                 len += sprintf(buf + len, "%10llu\n", (u64)
1592                         jiffies64_to_msecs(devfreq->stats.time_in_state[i]));
1593         }
1594
1595         len += sprintf(buf + len, "Total transition : %u\n",
1596                                         devfreq->stats.total_trans);
1597         return len;
1598 }
1599
1600 static ssize_t trans_stat_store(struct device *dev,
1601                                 struct device_attribute *attr,
1602                                 const char *buf, size_t count)
1603 {
1604         struct devfreq *df = to_devfreq(dev);
1605         int err, value;
1606
1607         if (df->profile->max_state == 0)
1608                 return count;
1609
1610         err = kstrtoint(buf, 10, &value);
1611         if (err || value != 0)
1612                 return -EINVAL;
1613
1614         mutex_lock(&df->lock);
1615         memset(df->stats.time_in_state, 0, (df->profile->max_state *
1616                                         sizeof(*df->stats.time_in_state)));
1617         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1618                                         df->profile->max_state,
1619                                         df->profile->max_state));
1620         df->stats.total_trans = 0;
1621         df->stats.last_update = get_jiffies_64();
1622         mutex_unlock(&df->lock);
1623
1624         return count;
1625 }
1626 static DEVICE_ATTR_RW(trans_stat);
1627
1628 static struct attribute *devfreq_attrs[] = {
1629         &dev_attr_name.attr,
1630         &dev_attr_governor.attr,
1631         &dev_attr_available_governors.attr,
1632         &dev_attr_cur_freq.attr,
1633         &dev_attr_available_frequencies.attr,
1634         &dev_attr_target_freq.attr,
1635         &dev_attr_polling_interval.attr,
1636         &dev_attr_min_freq.attr,
1637         &dev_attr_max_freq.attr,
1638         &dev_attr_trans_stat.attr,
1639         NULL,
1640 };
1641 ATTRIBUTE_GROUPS(devfreq);
1642
1643 /**
1644  * devfreq_summary_show() - Show the summary of the devfreq devices
1645  * @s:          seq_file instance to show the summary of devfreq devices
1646  * @data:       not used
1647  *
1648  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1649  * It helps that user can know the detailed information of the devfreq devices.
1650  *
1651  * Return 0 always because it shows the information without any data change.
1652  */
1653 static int devfreq_summary_show(struct seq_file *s, void *data)
1654 {
1655         struct devfreq *devfreq;
1656         struct devfreq *p_devfreq = NULL;
1657         unsigned long cur_freq, min_freq, max_freq;
1658         unsigned int polling_ms;
1659
1660         seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
1661                         "dev_name",
1662                         "dev",
1663                         "parent_dev",
1664                         "governor",
1665                         "polling_ms",
1666                         "cur_freq_Hz",
1667                         "min_freq_Hz",
1668                         "max_freq_Hz");
1669         seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
1670                         "------------------------------",
1671                         "----------",
1672                         "----------",
1673                         "---------------",
1674                         "----------",
1675                         "------------",
1676                         "------------",
1677                         "------------");
1678
1679         mutex_lock(&devfreq_list_lock);
1680
1681         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1682 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1683                 if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
1684                                                         DEVFREQ_NAME_LEN)) {
1685                         struct devfreq_passive_data *data = devfreq->data;
1686
1687                         if (data)
1688                                 p_devfreq = data->parent;
1689                 } else {
1690                         p_devfreq = NULL;
1691                 }
1692 #endif
1693
1694                 mutex_lock(&devfreq->lock);
1695                 cur_freq = devfreq->previous_freq,
1696                 get_freq_range(devfreq, &min_freq, &max_freq);
1697                 polling_ms = devfreq->profile->polling_ms,
1698                 mutex_unlock(&devfreq->lock);
1699
1700                 seq_printf(s,
1701                         "%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
1702                         dev_name(devfreq->dev.parent),
1703                         dev_name(&devfreq->dev),
1704                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1705                         devfreq->governor_name,
1706                         polling_ms,
1707                         cur_freq,
1708                         min_freq,
1709                         max_freq);
1710         }
1711
1712         mutex_unlock(&devfreq_list_lock);
1713
1714         return 0;
1715 }
1716 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1717
1718 static int __init devfreq_init(void)
1719 {
1720         devfreq_class = class_create(THIS_MODULE, "devfreq");
1721         if (IS_ERR(devfreq_class)) {
1722                 pr_err("%s: couldn't create class\n", __FILE__);
1723                 return PTR_ERR(devfreq_class);
1724         }
1725
1726         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1727         if (!devfreq_wq) {
1728                 class_destroy(devfreq_class);
1729                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1730                 return -ENOMEM;
1731         }
1732         devfreq_class->dev_groups = devfreq_groups;
1733
1734         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
1735         debugfs_create_file("devfreq_summary", 0444,
1736                                 devfreq_debugfs, NULL,
1737                                 &devfreq_summary_fops);
1738
1739         return 0;
1740 }
1741 subsys_initcall(devfreq_init);
1742
1743 /*
1744  * The following are helper functions for devfreq user device drivers with
1745  * OPP framework.
1746  */
1747
1748 /**
1749  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1750  *                           freq value given to target callback.
1751  * @dev:        The devfreq user device. (parent of devfreq)
1752  * @freq:       The frequency given to target function
1753  * @flags:      Flags handed from devfreq framework.
1754  *
1755  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1756  * use.
1757  */
1758 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1759                                            unsigned long *freq,
1760                                            u32 flags)
1761 {
1762         struct dev_pm_opp *opp;
1763
1764         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1765                 /* The freq is an upper bound. opp should be lower */
1766                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1767
1768                 /* If not available, use the closest opp */
1769                 if (opp == ERR_PTR(-ERANGE))
1770                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1771         } else {
1772                 /* The freq is an lower bound. opp should be higher */
1773                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1774
1775                 /* If not available, use the closest opp */
1776                 if (opp == ERR_PTR(-ERANGE))
1777                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1778         }
1779
1780         return opp;
1781 }
1782 EXPORT_SYMBOL(devfreq_recommended_opp);
1783
1784 /**
1785  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1786  *                                   for any changes in the OPP availability
1787  *                                   changes
1788  * @dev:        The devfreq user device. (parent of devfreq)
1789  * @devfreq:    The devfreq object.
1790  */
1791 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1792 {
1793         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1794 }
1795 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1796
1797 /**
1798  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1799  *                                     notified for any changes in the OPP
1800  *                                     availability changes anymore.
1801  * @dev:        The devfreq user device. (parent of devfreq)
1802  * @devfreq:    The devfreq object.
1803  *
1804  * At exit() callback of devfreq_dev_profile, this must be included if
1805  * devfreq_recommended_opp is used.
1806  */
1807 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1808 {
1809         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1810 }
1811 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1812
1813 static void devm_devfreq_opp_release(struct device *dev, void *res)
1814 {
1815         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1816 }
1817
1818 /**
1819  * devm_devfreq_register_opp_notifier() - Resource-managed
1820  *                                        devfreq_register_opp_notifier()
1821  * @dev:        The devfreq user device. (parent of devfreq)
1822  * @devfreq:    The devfreq object.
1823  */
1824 int devm_devfreq_register_opp_notifier(struct device *dev,
1825                                        struct devfreq *devfreq)
1826 {
1827         struct devfreq **ptr;
1828         int ret;
1829
1830         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1831         if (!ptr)
1832                 return -ENOMEM;
1833
1834         ret = devfreq_register_opp_notifier(dev, devfreq);
1835         if (ret) {
1836                 devres_free(ptr);
1837                 return ret;
1838         }
1839
1840         *ptr = devfreq;
1841         devres_add(dev, ptr);
1842
1843         return 0;
1844 }
1845 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1846
1847 /**
1848  * devm_devfreq_unregister_opp_notifier() - Resource-managed
1849  *                                          devfreq_unregister_opp_notifier()
1850  * @dev:        The devfreq user device. (parent of devfreq)
1851  * @devfreq:    The devfreq object.
1852  */
1853 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1854                                          struct devfreq *devfreq)
1855 {
1856         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1857                                devm_devfreq_dev_match, devfreq));
1858 }
1859 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1860
1861 /**
1862  * devfreq_register_notifier() - Register a driver with devfreq
1863  * @devfreq:    The devfreq object.
1864  * @nb:         The notifier block to register.
1865  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1866  */
1867 int devfreq_register_notifier(struct devfreq *devfreq,
1868                               struct notifier_block *nb,
1869                               unsigned int list)
1870 {
1871         int ret = 0;
1872
1873         if (!devfreq)
1874                 return -EINVAL;
1875
1876         switch (list) {
1877         case DEVFREQ_TRANSITION_NOTIFIER:
1878                 ret = srcu_notifier_chain_register(
1879                                 &devfreq->transition_notifier_list, nb);
1880                 break;
1881         default:
1882                 ret = -EINVAL;
1883         }
1884
1885         return ret;
1886 }
1887 EXPORT_SYMBOL(devfreq_register_notifier);
1888
1889 /*
1890  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1891  * @devfreq:    The devfreq object.
1892  * @nb:         The notifier block to be unregistered.
1893  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1894  */
1895 int devfreq_unregister_notifier(struct devfreq *devfreq,
1896                                 struct notifier_block *nb,
1897                                 unsigned int list)
1898 {
1899         int ret = 0;
1900
1901         if (!devfreq)
1902                 return -EINVAL;
1903
1904         switch (list) {
1905         case DEVFREQ_TRANSITION_NOTIFIER:
1906                 ret = srcu_notifier_chain_unregister(
1907                                 &devfreq->transition_notifier_list, nb);
1908                 break;
1909         default:
1910                 ret = -EINVAL;
1911         }
1912
1913         return ret;
1914 }
1915 EXPORT_SYMBOL(devfreq_unregister_notifier);
1916
1917 struct devfreq_notifier_devres {
1918         struct devfreq *devfreq;
1919         struct notifier_block *nb;
1920         unsigned int list;
1921 };
1922
1923 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1924 {
1925         struct devfreq_notifier_devres *this = res;
1926
1927         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1928 }
1929
1930 /**
1931  * devm_devfreq_register_notifier()
1932  *      - Resource-managed devfreq_register_notifier()
1933  * @dev:        The devfreq user device. (parent of devfreq)
1934  * @devfreq:    The devfreq object.
1935  * @nb:         The notifier block to be unregistered.
1936  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1937  */
1938 int devm_devfreq_register_notifier(struct device *dev,
1939                                 struct devfreq *devfreq,
1940                                 struct notifier_block *nb,
1941                                 unsigned int list)
1942 {
1943         struct devfreq_notifier_devres *ptr;
1944         int ret;
1945
1946         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1947                                 GFP_KERNEL);
1948         if (!ptr)
1949                 return -ENOMEM;
1950
1951         ret = devfreq_register_notifier(devfreq, nb, list);
1952         if (ret) {
1953                 devres_free(ptr);
1954                 return ret;
1955         }
1956
1957         ptr->devfreq = devfreq;
1958         ptr->nb = nb;
1959         ptr->list = list;
1960         devres_add(dev, ptr);
1961
1962         return 0;
1963 }
1964 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1965
1966 /**
1967  * devm_devfreq_unregister_notifier()
1968  *      - Resource-managed devfreq_unregister_notifier()
1969  * @dev:        The devfreq user device. (parent of devfreq)
1970  * @devfreq:    The devfreq object.
1971  * @nb:         The notifier block to be unregistered.
1972  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1973  */
1974 void devm_devfreq_unregister_notifier(struct device *dev,
1975                                       struct devfreq *devfreq,
1976                                       struct notifier_block *nb,
1977                                       unsigned int list)
1978 {
1979         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1980                                devm_devfreq_dev_match, devfreq));
1981 }
1982 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);