drivers/video/tegra/host/gr3d/pod_scaling.c

   1 /*
   2  * drivers/video/tegra/host/gr3d/pod_scaling.c
   3  *
   4  * Tegra Graphics Host 3D clock scaling
   5  *
   6  * Copyright (c) 2012-2014, NVIDIA CORPORATION.  All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /*
  22  * Power-on-demand clock scaling for nvhost devices
  23  *
  24  * devfreq calls nvhost_pod_estimate_freq() for estimating the new
  25  * frequency for the device. The clocking is done using two properties:
  26  *
  27  *  (1) Usually the governor receives actively throughput hints that indicate
  28  *      whether scaling up or down is required.
  29  *  (2) The load of the device is estimated using the busy times from the
  30  *      device profile. This information indicates if the device frequency
  31  *      should be altered.
  32  *
  33  */
  34
  35 #include <linux/devfreq.h>
  36 #include <linux/debugfs.h>
  37 #include <linux/types.h>
  38 #include <linux/clk.h>
  39 #include <linux/export.h>
  40 #include <linux/slab.h>
  41 #include <linux/clk/tegra.h>
  42 #include <linux/tegra-soc.h>
  43
  44 #include <linux/notifier.h>
  45 #include <linux/tegra-throughput.h>
  46
  47 #include <linux/notifier.h>
  48 #include <linux/tegra-throughput.h>
  49
  50 #define CREATE_TRACE_POINTS
  51 #include <trace/events/nvhost_podgov.h>
  52
  53 #include <governor.h>
  54
  55 #include "nvhost_acm.h"
  56 #include "scale3d.h"
  57 #include "dev.h"
  58
  59 #define GET_TARGET_FREQ_DONTSCALE       1
  60
  61 /* time frame for load and hint tracking - when events come in at a larger
  62  * interval, this probably indicates the current estimates are stale
  63  */
  64 #define GR3D_TIMEFRAME 1000000 /* 1 sec */
  65
  66 /* the number of frames to use in the running average of load estimates and
  67  * throughput hints. Choosing 6 frames targets a window of about 100 msec.
  68  * Large flucutuations in frame times require a window that's large enough to
  69  * prevent spiky scaling behavior, which in turn exacerbates frame rate
  70  * instability.
  71  */
  72
  73 static void podgov_enable(struct devfreq *df, int enable);
  74 static void podgov_set_user_ctl(struct devfreq *df, int enable);
  75
  76 static struct devfreq_governor nvhost_podgov;
  77
  78 /*******************************************************************************
  79  * podgov_info_rec - gr3d scaling governor specific parameters
  80  ******************************************************************************/
  81
  82 struct podgov_info_rec {
  83
  84         int                     enable;
  85         int                     init;
  86
  87         ktime_t                 last_throughput_hint;
  88         ktime_t                 last_scale;
  89
  90         struct delayed_work     idle_timer;
  91
  92         unsigned int            p_slowdown_delay;
  93         unsigned int            p_block_window;
  94         unsigned int            p_use_throughput_hint;
  95         unsigned int            p_hint_lo_limit;
  96         unsigned int            p_hint_hi_limit;
  97         unsigned int            p_scaleup_limit;
  98         unsigned int            p_scaledown_limit;
  99         unsigned int            p_smooth;
 100         int                     p_damp;
 101         int                     p_load_max;
 102         int                     p_load_target;
 103         int                     p_bias;
 104         unsigned int            p_user;
 105         unsigned int            p_freq_request;
 106
 107         long                    idle;
 108
 109         int                     adjustment_type;
 110         unsigned long           adjustment_frequency;
 111
 112         int                     last_event_type;
 113
 114         struct devfreq          *power_manager;
 115         struct dentry           *debugdir;
 116
 117         unsigned long           *freqlist;
 118         int                     freq_count;
 119
 120         unsigned int            idle_avg;
 121         int                     freq_avg;
 122         unsigned int            hint_avg;
 123         int                     block;
 124         struct kobj_attribute   enable_3d_scaling_attr;
 125         struct kobj_attribute   user_attr;
 126         struct kobj_attribute   freq_request_attr;
 127
 128         struct notifier_block   throughput_hint_notifier;
 129 };
 130
 131 /*******************************************************************************
 132  * Adjustment type is used to tell the source that requested frequency re-
 133  * estimation. Type ADJUSTMENT_LOCAL indicates that the re-estimation was
 134  * initiated by the governor itself. This happens when one of the worker
 135  * threads want to adjust the frequency.
 136  *
 137  * ADJUSTMENT_DEVICE_REQ (default value) indicates that the adjustment was
 138  * initiated by a device event.
 139  ******************************************************************************/
 140
 141 enum podgov_adjustment_type {
 142         ADJUSTMENT_LOCAL = 0,
 143         ADJUSTMENT_DEVICE_REQ = 1
 144 };
 145
 146
 147 static void stop_podgov_workers(struct podgov_info_rec *podgov)
 148 {
 149         /* idle_timer can rearm itself */
 150         do {
 151                 cancel_delayed_work_sync(&podgov->idle_timer);
 152         } while (delayed_work_pending(&podgov->idle_timer));
 153 }
 154
 155 /*******************************************************************************
 156  * scaling_limit(df, freq)
 157  *
 158  * Limit the given frequency
 159  ******************************************************************************/
 160
 161 static void scaling_limit(struct devfreq *df, unsigned long *freq)
 162 {
 163         if (*freq < df->min_freq)
 164                 *freq = df->min_freq;
 165         else if (*freq > df->max_freq)
 166                 *freq = df->max_freq;
 167 }
 168
 169 /*******************************************************************************
 170  * nvhost_pod_suspend(dev)
 171  *
 172  * Prepare the device for suspend
 173  ******************************************************************************/
 174
 175 static void nvhost_pod_suspend(struct devfreq *df)
 176 {
 177         struct podgov_info_rec *podgov;
 178
 179         mutex_lock(&df->lock);
 180
 181         podgov = df->data;
 182         if (!(df->governor == &nvhost_podgov &&
 183               podgov && podgov->enable)) {
 184                 mutex_unlock(&df->lock);
 185                 return;
 186         }
 187         mutex_unlock(&df->lock);
 188
 189         stop_podgov_workers(podgov);
 190 }
 191
 192 /*******************************************************************************
 193  * podgov_enable(dev, enable)
 194  *
 195  * This function enables (enable=1) or disables (enable=0) the automatic scaling
 196  * of the device. If the device is disabled, the device's clock is set to its
 197  * maximum.
 198  ******************************************************************************/
 199
 200 static void podgov_enable(struct devfreq *df, int enable)
 201 {
 202         struct device *dev = df->dev.parent;
 203         struct podgov_info_rec *podgov;
 204
 205         /* make sure the device is alive before doing any scaling */
 206         pm_runtime_get_noresume(dev);
 207
 208         mutex_lock(&df->lock);
 209
 210         podgov = df->data;
 211
 212         trace_podgov_enabled(enable);
 213
 214         /* bad configuration. quit. */
 215         if (df->min_freq == df->max_freq)
 216                 goto exit_unlock;
 217
 218         /* store the enable information */
 219         podgov->enable = enable;
 220
 221         /* skip local adjustment if we are enabling or the device is
 222          * suspended */
 223         if (enable || !pm_runtime_active(dev))
 224                 goto exit_unlock;
 225
 226         /* full speed */
 227         podgov->adjustment_frequency = df->max_freq;
 228         podgov->adjustment_type = ADJUSTMENT_LOCAL;
 229         update_devfreq(df);
 230
 231         mutex_unlock(&df->lock);
 232
 233         pm_runtime_put(dev);
 234
 235         stop_podgov_workers(podgov);
 236
 237         return;
 238
 239 exit_unlock:
 240         mutex_unlock(&df->lock);
 241         pm_runtime_put(dev);
 242 }
 243
 244 /*****************************************************************************
 245  * podgov_set_user_ctl(dev, user)
 246  *
 247  * This function enables or disables user control of the gpu. If user control
 248  * is enabled, setting the freq_request controls the gpu frequency, and other
 249  * gpu scaling mechanisms are disabled.
 250  ******************************************************************************/
 251
 252 static void podgov_set_user_ctl(struct devfreq *df, int user)
 253 {
 254         struct device *dev = df->dev.parent;
 255         struct podgov_info_rec *podgov;
 256         int old_user;
 257
 258         /* make sure the device is alive before doing any scaling */
 259         pm_runtime_get_noresume(dev);
 260
 261         mutex_lock(&df->lock);
 262         podgov = df->data;
 263
 264         trace_podgov_set_user_ctl(user);
 265
 266         /* store the new user value */
 267         old_user = podgov->p_user;
 268         podgov->p_user = user;
 269
 270         /* skip scaling, if scaling (or the whole device) is turned off
 271          * - or the scaling already was in user mode */
 272         if (!pm_runtime_active(dev) || !podgov->enable ||
 273             !(user && !old_user))
 274                 goto exit_unlock;
 275
 276         /* write request */
 277         podgov->adjustment_frequency = podgov->p_freq_request;
 278         podgov->adjustment_type = ADJUSTMENT_LOCAL;
 279         update_devfreq(df);
 280
 281         mutex_unlock(&df->lock);
 282         pm_runtime_put(dev);
 283
 284         stop_podgov_workers(podgov);
 285
 286         return;
 287
 288 exit_unlock:
 289         mutex_unlock(&df->lock);
 290         pm_runtime_put(dev);
 291 }
 292
 293 /*****************************************************************************
 294  * podgov_set_freq_request(dev, user)
 295  *
 296  * Set the current freq request. If scaling is enabled, and podgov user space
 297  * control is enabled, this will set the gpu frequency.
 298  ******************************************************************************/
 299
 300 static void podgov_set_freq_request(struct devfreq *df, int freq_request)
 301 {
 302         struct device *dev = df->dev.parent;
 303         struct podgov_info_rec *podgov;
 304
 305         /* make sure the device is alive before doing any scaling */
 306         pm_runtime_get_noresume(dev);
 307
 308         mutex_lock(&df->lock);
 309
 310         podgov = df->data;
 311
 312         trace_podgov_set_freq_request(freq_request);
 313
 314         podgov->p_freq_request = freq_request;
 315
 316         /* update the request only if podgov is enabled, device is turned on
 317          * and the scaling is in user mode */
 318         if (podgov->enable && podgov->p_user &&
 319             pm_runtime_active(dev)) {
 320                 podgov->adjustment_frequency = freq_request;
 321                 podgov->adjustment_type = ADJUSTMENT_LOCAL;
 322                 update_devfreq(df);
 323         }
 324
 325         mutex_unlock(&df->lock);
 326         pm_runtime_put(dev);
 327 }
 328
 329
 330 /*******************************************************************************
 331  * freq = scaling_state_check(df, time)
 332  *
 333  * This handler is called to adjust the frequency of the device. The function
 334  * returns the desired frequency for the clock. If there is no need to tune the
 335  * clock immediately, 0 is returned.
 336  ******************************************************************************/
 337
 338 static unsigned long scaling_state_check(struct devfreq *df, ktime_t time)
 339 {
 340         struct podgov_info_rec *podgov = df->data;
 341         unsigned long dt;
 342         long max_boost, load, damp, freq, boost, res;
 343
 344         dt = (unsigned long) ktime_us_delta(time, podgov->last_scale);
 345         if (dt < podgov->p_block_window || df->previous_freq == 0)
 346                 return 0;
 347
 348         /* convert to mhz to avoid overflow */
 349         freq = df->previous_freq / 1000000;
 350         max_boost = (df->max_freq/3) / 1000000;
 351
 352         /* calculate and trace load */
 353         load = 1000 - podgov->idle_avg;
 354         trace_podgov_busy(load);
 355         damp = podgov->p_damp;
 356
 357         if ((1000 - podgov->idle) > podgov->p_load_max) {
 358                 /* if too busy, scale up max/3, do not damp */
 359                 boost = max_boost;
 360                 damp = 10;
 361
 362         } else {
 363                 /* boost = bias * freq * (load - target)/target */
 364                 boost = (load - podgov->p_load_target);
 365                 boost *= (podgov->p_bias * freq);
 366                 boost /= (100 * podgov->p_load_target);
 367
 368                 /* clamp to max boost */
 369                 boost = (boost < max_boost) ? boost : max_boost;
 370         }
 371
 372         /* calculate new request */
 373         res = freq + boost;
 374
 375         /* Maintain average request */
 376         podgov->freq_avg = (podgov->freq_avg * podgov->p_smooth) + res;
 377         podgov->freq_avg /= (podgov->p_smooth+1);
 378
 379         /* Applying damping to frequencies */
 380         res = ((damp * res) + ((10 - damp)*podgov->freq_avg)) / 10;
 381
 382         /* Convert to hz, limit, and apply */
 383         res = res * 1000000;
 384         scaling_limit(df, &res);
 385         trace_podgov_scaling_state_check(df->previous_freq, res);
 386         return res;
 387 }
 388
 389 /*******************************************************************************
 390  * freqlist_up(podgov, target, steps)
 391  *
 392  * This function determines the frequency that is "steps" frequency steps
 393  * higher compared to the target frequency.
 394  ******************************************************************************/
 395
 396 int freqlist_up(struct podgov_info_rec *podgov, unsigned long target, int steps)
 397 {
 398         int i, pos;
 399
 400         for (i = 0; i < podgov->freq_count; i++)
 401                 if (podgov->freqlist[i] >= target)
 402                         break;
 403
 404         pos = min(podgov->freq_count - 1, i + steps);
 405         return podgov->freqlist[pos];
 406 }
 407
 408 /*******************************************************************************
 409  * freqlist_down(podgov, target, steps)
 410  *
 411  * This function determines the frequency that is "steps" frequency steps
 412  * lower compared to the target frequency.
 413  ******************************************************************************/
 414
 415 int freqlist_down(struct podgov_info_rec *podgov, unsigned long target, int steps)
 416 {
 417         int i, pos;
 418
 419         for (i = podgov->freq_count - 1; i >= 0; i--)
 420                 if (podgov->freqlist[i] <= target)
 421                         break;
 422
 423         pos = max(0, i - steps);
 424         return podgov->freqlist[pos];
 425 }
 426
 427 /*******************************************************************************
 428  * podgov_idle_handler(work)
 429  *
 430  * This handler is called after the device has been idle long enough. This
 431  * handler forms a (positive) feedback loop by notifying idle to the device.
 432  ******************************************************************************/
 433
 434 static void podgov_idle_handler(struct work_struct *work)
 435 {
 436         struct delayed_work *idle_timer =
 437                 container_of(work, struct delayed_work, work);
 438         struct podgov_info_rec *podgov =
 439                 container_of(idle_timer, struct podgov_info_rec, idle_timer);
 440         struct devfreq *df = podgov->power_manager;
 441
 442         mutex_lock(&df->lock);
 443
 444         if (!podgov->enable) {
 445                 mutex_unlock(&df->lock);
 446                 return;
 447         }
 448
 449         if (!podgov->last_event_type &&
 450             df->previous_freq > df->min_freq &&
 451             podgov->p_user == false)
 452                 update_devfreq(df);
 453
 454         mutex_unlock(&df->lock);
 455 }
 456
 457 #ifdef CONFIG_TEGRA_THROUGHPUT
 458 /*******************************************************************************
 459  * nvhost_scale3d_set_throughput_hint(hint)
 460  *
 461  * This function can be used to request scaling up or down based on the
 462  * required throughput
 463  ******************************************************************************/
 464
 465 static int nvhost_scale3d_set_throughput_hint(struct notifier_block *nb,
 466                                               unsigned long action, void *data)
 467 {
 468         struct podgov_info_rec *podgov =
 469                 container_of(nb, struct podgov_info_rec,
 470                              throughput_hint_notifier);
 471         struct devfreq *df = podgov->power_manager;
 472         struct device *dev = df->dev.parent;
 473         int hint = tegra_throughput_get_hint();
 474         long idle;
 475         unsigned long curr, target;
 476         int avg_idle, avg_hint, scale_score;
 477         unsigned int smooth;
 478
 479         /* make sure the device is alive before doing any scaling */
 480         pm_runtime_get_noresume(dev);
 481         if (!pm_runtime_active(dev)) {
 482                 pm_runtime_put(dev);
 483                 return 0;
 484         }
 485
 486         mutex_lock(&df->lock);
 487
 488         podgov->block--;
 489
 490         if (!podgov->enable ||
 491                 !podgov->p_use_throughput_hint ||
 492                 podgov->block > 0)
 493                 goto exit_unlock;
 494
 495         trace_podgov_hint(podgov->idle, hint);
 496         podgov->last_throughput_hint = ktime_get();
 497
 498         curr = df->previous_freq;
 499         idle = podgov->idle;
 500         avg_idle = podgov->idle_avg;
 501         smooth = podgov->p_smooth;
 502
 503         /* compute averages usings exponential-moving-average */
 504         avg_hint = ((smooth*podgov->hint_avg + hint)/(smooth+1));
 505         podgov->hint_avg = avg_hint;
 506
 507         /* set the target using avg_hint and avg_idle */
 508         target = curr;
 509         if (avg_hint < podgov->p_hint_lo_limit) {
 510                 target = freqlist_up(podgov, curr, 1);
 511         } else {
 512                 scale_score = avg_idle + avg_hint;
 513                 if (scale_score > podgov->p_scaledown_limit)
 514                         target = freqlist_down(podgov, curr, 1);
 515                 else if (scale_score < podgov->p_scaleup_limit
 516                                 && hint < podgov->p_hint_hi_limit)
 517                         target = freqlist_up(podgov, curr, 1);
 518         }
 519
 520         /* clamp and apply target */
 521         scaling_limit(df, &target);
 522         if (target != curr) {
 523                 podgov->block = podgov->p_smooth;
 524                 trace_podgov_do_scale(df->previous_freq, target);
 525                 podgov->adjustment_frequency = target;
 526                 podgov->adjustment_type = ADJUSTMENT_LOCAL;
 527                 update_devfreq(df);
 528         }
 529
 530         trace_podgov_print_target(idle, avg_idle, curr / 1000000, target, hint,
 531                 avg_hint);
 532
 533 exit_unlock:
 534         mutex_unlock(&df->lock);
 535         pm_runtime_put(dev);
 536         return NOTIFY_OK;
 537 }
 538 #endif
 539
 540 /*******************************************************************************
 541  * debugfs interface for controlling 3d clock scaling on the fly
 542  ******************************************************************************/
 543
 544 #ifdef CONFIG_DEBUG_FS
 545
 546 static void nvhost_scale3d_debug_init(struct devfreq *df)
 547 {
 548         struct podgov_info_rec *podgov = df->data;
 549         struct dentry *f;
 550         char dirname[128];
 551
 552         snprintf(dirname, sizeof(dirname), "%s_scaling",
 553                 to_platform_device(df->dev.parent)->name);
 554
 555         if (!podgov)
 556                 return;
 557
 558         podgov->debugdir = debugfs_create_dir(dirname, NULL);
 559         if (!podgov->debugdir) {
 560                 pr_err("podgov: can\'t create debugfs directory\n");
 561                 return;
 562         }
 563
 564 #define CREATE_PODGOV_FILE(fname) \
 565         do {\
 566                 f = debugfs_create_u32(#fname, S_IRUGO | S_IWUSR, \
 567                         podgov->debugdir, &podgov->p_##fname); \
 568                 if (NULL == f) { \
 569                         pr_err("podgov: can\'t create file " #fname "\n"); \
 570                         return; \
 571                 } \
 572         } while (0)
 573
 574         CREATE_PODGOV_FILE(block_window);
 575         CREATE_PODGOV_FILE(load_max);
 576         CREATE_PODGOV_FILE(load_target);
 577         CREATE_PODGOV_FILE(bias);
 578         CREATE_PODGOV_FILE(damp);
 579         CREATE_PODGOV_FILE(use_throughput_hint);
 580         CREATE_PODGOV_FILE(hint_hi_limit);
 581         CREATE_PODGOV_FILE(hint_lo_limit);
 582         CREATE_PODGOV_FILE(scaleup_limit);
 583         CREATE_PODGOV_FILE(scaledown_limit);
 584         CREATE_PODGOV_FILE(smooth);
 585         CREATE_PODGOV_FILE(slowdown_delay);
 586 #undef CREATE_PODGOV_FILE
 587 }
 588
 589 static void nvhost_scale3d_debug_deinit(struct devfreq *df)
 590 {
 591         struct podgov_info_rec *podgov = df->data;
 592
 593         debugfs_remove_recursive(podgov->debugdir);
 594 }
 595
 596 #else
 597 static void nvhost_scale3d_debug_init(struct devfreq *df)
 598 {
 599         (void)df;
 600 }
 601
 602 static void nvhost_scale3d_debug_deinit(struct devfreq *df)
 603 {
 604         (void)df;
 605 }
 606 #endif
 607
 608 /*******************************************************************************
 609  * sysfs interface for enabling/disabling 3d scaling
 610  ******************************************************************************/
 611
 612 static ssize_t enable_3d_scaling_show(struct kobject *kobj,
 613                                       struct kobj_attribute *attr,
 614                                       char *buf)
 615 {
 616         struct podgov_info_rec *podgov = container_of(attr,
 617                                                       struct podgov_info_rec,
 618                                                       enable_3d_scaling_attr);
 619         ssize_t res;
 620
 621         res = snprintf(buf, PAGE_SIZE, "%d\n", podgov->enable);
 622
 623         return res;
 624 }
 625
 626 static ssize_t enable_3d_scaling_store(struct kobject *kobj,
 627                                        struct kobj_attribute *attr,
 628                                        const char *buf, size_t count)
 629 {
 630         struct podgov_info_rec *podgov = container_of(attr,
 631                                                       struct podgov_info_rec,
 632                                                       enable_3d_scaling_attr);
 633         unsigned long val = 0;
 634
 635         if (kstrtoul(buf, 10, &val) < 0)
 636                 return -EINVAL;
 637
 638         podgov_enable(podgov->power_manager, val);
 639
 640         return count;
 641 }
 642
 643 /*******************************************************************************
 644  * sysfs interface for user space control
 645  * user = [0,1] disables / enabled user space control
 646  * freq_request is the sysfs node user space writes frequency requests to
 647  ******************************************************************************/
 648
 649 static ssize_t user_show(struct kobject *kobj,
 650                          struct kobj_attribute *attr,
 651                          char *buf)
 652 {
 653         struct podgov_info_rec *podgov =
 654                 container_of(attr, struct podgov_info_rec, user_attr);
 655         ssize_t res;
 656
 657         res = snprintf(buf, PAGE_SIZE, "%d\n", podgov->p_user);
 658
 659         return res;
 660 }
 661
 662 static ssize_t user_store(struct kobject *kobj,
 663                           struct kobj_attribute *attr,
 664                           const char *buf, size_t count)
 665 {
 666         struct podgov_info_rec *podgov =
 667                 container_of(attr, struct podgov_info_rec, user_attr);
 668         unsigned long val = 0;
 669
 670         if (kstrtoul(buf, 10, &val) < 0)
 671                 return -EINVAL;
 672
 673         podgov_set_user_ctl(podgov->power_manager, val);
 674
 675         return count;
 676 }
 677
 678 static ssize_t freq_request_show(struct kobject *kobj,
 679                                  struct kobj_attribute *attr,
 680                                  char *buf)
 681 {
 682         struct podgov_info_rec *podgov =
 683                 container_of(attr, struct podgov_info_rec, freq_request_attr);
 684         ssize_t res;
 685
 686         res = snprintf(buf, PAGE_SIZE, "%d\n", podgov->p_freq_request);
 687
 688         return res;
 689 }
 690
 691 static ssize_t freq_request_store(struct kobject *kobj,
 692                                   struct kobj_attribute *attr,
 693                                   const char *buf, size_t count)
 694 {
 695         struct podgov_info_rec *podgov =
 696                 container_of(attr, struct podgov_info_rec, freq_request_attr);
 697         unsigned long val = 0;
 698
 699         if (kstrtoul(buf, 10, &val) < 0)
 700                 return -EINVAL;
 701
 702         podgov_set_freq_request(podgov->power_manager, val);
 703
 704         return count;
 705 }
 706
 707 /*******************************************************************************
 708  * nvhost_pod_estimate_freq(df, freq)
 709  *
 710  * This function is called for re-estimating the frequency. The function is
 711  * called in three conditions:
 712  *
 713  *  (1) Internal request to change the frequency. In this case a new clock
 714  *      target is immediately set for the device.
 715  *  (2) Call from the client (something has happened and re-estimation
 716  *      is required).
 717  *  (3) Some other reason (i.e. periodic call)
 718  *
 719  ******************************************************************************/
 720
 721 static int nvhost_pod_estimate_freq(struct devfreq *df,
 722                                     unsigned long *freq)
 723 {
 724         struct podgov_info_rec *podgov = df->data;
 725         struct devfreq_dev_status dev_stat;
 726         int stat;
 727         ktime_t now;
 728
 729         stat = df->profile->get_dev_status(df->dev.parent, &dev_stat);
 730         if (stat < 0)
 731                 return stat;
 732
 733         /* Ensure maximal clock when scaling is disabled */
 734         if (!podgov->enable) {
 735                 *freq = df->max_freq;
 736                 return 0;
 737         }
 738
 739         if (podgov->p_user) {
 740                 *freq = podgov->p_freq_request;
 741                 return 0;
 742         }
 743
 744         stat = 0;
 745         now = ktime_get();
 746
 747         /* Local adjustments (i.e. requests from kernel threads) are
 748          * handled here */
 749
 750         if (podgov->adjustment_type == ADJUSTMENT_LOCAL) {
 751
 752                 podgov->adjustment_type = ADJUSTMENT_DEVICE_REQ;
 753
 754                 /* Do not do unnecessary scaling */
 755                 scaling_limit(df, &podgov->adjustment_frequency);
 756
 757                 /* Round the frequency and check if we're already there */
 758                 if (freqlist_up(podgov, podgov->adjustment_frequency, 0) ==
 759                     dev_stat.current_frequency)
 760                         return GET_TARGET_FREQ_DONTSCALE;
 761
 762                 trace_podgov_estimate_freq(df->previous_freq,
 763                         podgov->adjustment_frequency);
 764
 765                 *freq = podgov->adjustment_frequency;
 766                 return 0;
 767         }
 768
 769         *freq = dev_stat.current_frequency;
 770
 771         /* Sustain local variables */
 772         podgov->last_event_type = dev_stat.busy;
 773         podgov->idle = 1000 * (dev_stat.total_time - dev_stat.busy_time);
 774         podgov->idle = podgov->idle / dev_stat.total_time;
 775         podgov->idle_avg = (podgov->p_smooth * podgov->idle_avg) +
 776                 podgov->idle;
 777         podgov->idle_avg = podgov->idle_avg / (podgov->p_smooth + 1);
 778
 779         /* if throughput hint enabled, and last hint is recent enough, return */
 780         if (podgov->p_use_throughput_hint &&
 781                 ktime_us_delta(now, podgov->last_throughput_hint) < 1000000)
 782                 return GET_TARGET_FREQ_DONTSCALE;
 783
 784         if (dev_stat.busy) {
 785                 cancel_delayed_work(&podgov->idle_timer);
 786                 *freq = scaling_state_check(df, now);
 787         } else {
 788                 /* Launch a work to slowdown the gpu */
 789                 *freq = scaling_state_check(df, now);
 790                 schedule_delayed_work(&podgov->idle_timer,
 791                         msecs_to_jiffies(podgov->p_slowdown_delay));
 792         }
 793
 794         if (!(*freq) ||
 795             (freqlist_up(podgov, *freq, 0) == dev_stat.current_frequency))
 796                 return GET_TARGET_FREQ_DONTSCALE;
 797
 798         podgov->last_scale = now;
 799
 800         trace_podgov_estimate_freq(df->previous_freq, *freq);
 801
 802
 803         return 0;
 804 }
 805
 806 /*******************************************************************************
 807  * nvhost_pod_init(struct devfreq *df)
 808  *
 809  * Governor initialisation.
 810  ******************************************************************************/
 811
 812 static int nvhost_pod_init(struct devfreq *df)
 813 {
 814         struct podgov_info_rec *podgov;
 815         struct platform_device *d = to_platform_device(df->dev.parent);
 816         ktime_t now = ktime_get();
 817         enum tegra_chipid cid = tegra_get_chipid();
 818
 819         struct devfreq_dev_status dev_stat;
 820         int stat = 0;
 821
 822         struct kobj_attribute *attr = NULL;
 823
 824         podgov = kzalloc(sizeof(struct podgov_info_rec), GFP_KERNEL);
 825         if (!podgov)
 826                 goto err_alloc_podgov;
 827         df->data = (void *)podgov;
 828
 829         /* Initialise workers */
 830         INIT_DELAYED_WORK(&podgov->idle_timer, podgov_idle_handler);
 831
 832         /* Set scaling parameter defaults */
 833         podgov->enable = 1;
 834         podgov->block = 0;
 835         podgov->p_use_throughput_hint = 1;
 836
 837         if (!strcmp(d->name, "vic03.0")) {
 838                 podgov->p_load_max = 990;
 839                 podgov->p_load_target = 100;
 840                 podgov->p_bias = 80;
 841                 podgov->p_hint_lo_limit = 500;
 842                 podgov->p_hint_hi_limit = 997;
 843                 podgov->p_scaleup_limit = 1100;
 844                 podgov->p_scaledown_limit = 1300;
 845                 podgov->p_smooth = 30;
 846                 podgov->p_damp = 7;
 847         } else {
 848                 switch (cid) {
 849                 case TEGRA_CHIPID_TEGRA14:
 850                 case TEGRA_CHIPID_TEGRA11:
 851                 case TEGRA_CHIPID_TEGRA12:
 852                 case TEGRA_CHIPID_TEGRA13:
 853                         podgov->p_load_max = 900;
 854                         podgov->p_load_target = 700;
 855                         podgov->p_bias = 80;
 856                         podgov->p_hint_lo_limit = 500;
 857                         podgov->p_hint_hi_limit = 997;
 858                         podgov->p_scaleup_limit = 1100;
 859                         podgov->p_scaledown_limit = 1300;
 860                         podgov->p_smooth = 10;
 861                         podgov->p_damp = 7;
 862                         podgov->p_use_throughput_hint = 0;
 863                         break;
 864                 default:
 865                         pr_err("%s: un-supported chip id\n", __func__);
 866                         goto err_unsupported_chip_id;
 867                         break;
 868                 }
 869         }
 870
 871         podgov->p_slowdown_delay = 10;
 872         podgov->p_block_window = 50000;
 873         podgov->adjustment_type = ADJUSTMENT_DEVICE_REQ;
 874         podgov->p_user = 0;
 875
 876         /* Reset clock counters */
 877         podgov->last_throughput_hint = now;
 878         podgov->last_scale = now;
 879
 880         podgov->power_manager = df;
 881
 882         /* Get the current status of the device */
 883         stat = df->profile->get_dev_status(df->dev.parent, &dev_stat);
 884
 885         attr = &podgov->enable_3d_scaling_attr;
 886         attr->attr.name = "enable_3d_scaling";
 887         attr->attr.mode = S_IWUSR | S_IRUGO;
 888         attr->show = enable_3d_scaling_show;
 889         attr->store = enable_3d_scaling_store;
 890         sysfs_attr_init(&attr->attr);
 891         if (sysfs_create_file(&df->dev.parent->kobj, &attr->attr))
 892                 goto err_create_enable_sysfs_entry;
 893
 894         attr = &podgov->freq_request_attr;
 895         attr->attr.name = "freq_request";
 896         attr->attr.mode = S_IWUSR | S_IRUGO;
 897         attr->show = freq_request_show;
 898         attr->store = freq_request_store;
 899         sysfs_attr_init(&attr->attr);
 900         if (sysfs_create_file(&df->dev.parent->kobj, &attr->attr))
 901                 goto err_create_request_sysfs_entry;
 902
 903         attr = &podgov->user_attr;
 904         attr->attr.name = "user";
 905         attr->attr.mode = S_IWUSR | S_IRUGO;
 906         attr->show = user_show;
 907         attr->store = user_store;
 908         sysfs_attr_init(&attr->attr);
 909         if (sysfs_create_file(&df->dev.parent->kobj, &attr->attr))
 910                 goto err_create_user_sysfs_entry;
 911
 912         podgov->freq_count = df->profile->max_state;
 913         podgov->freqlist = df->profile->freq_table;
 914         if (!podgov->freq_count || !podgov->freqlist)
 915                 goto err_get_freqs;
 916
 917         /* store the limits */
 918         df->min_freq = podgov->freqlist[0];
 919         df->max_freq = podgov->freqlist[podgov->freq_count - 1];
 920         podgov->p_freq_request = df->max_freq;
 921
 922         podgov->idle_avg = 0;
 923         podgov->freq_avg = 0;
 924         podgov->hint_avg = 0;
 925
 926         nvhost_scale3d_debug_init(df);
 927
 928         /* register the governor to throughput hint notifier chain */
 929 #ifdef CONFIG_TEGRA_THROUGHPUT
 930         podgov->throughput_hint_notifier.notifier_call =
 931                 &nvhost_scale3d_set_throughput_hint;
 932         blocking_notifier_chain_register(&throughput_notifier_list,
 933                                          &podgov->throughput_hint_notifier);
 934 #endif
 935
 936         return 0;
 937
 938 err_get_freqs:
 939         sysfs_remove_file(&df->dev.parent->kobj, &podgov->user_attr.attr);
 940 err_create_user_sysfs_entry:
 941         sysfs_remove_file(&df->dev.parent->kobj,
 942                           &podgov->freq_request_attr.attr);
 943 err_create_request_sysfs_entry:
 944         sysfs_remove_file(&df->dev.parent->kobj,
 945                           &podgov->enable_3d_scaling_attr.attr);
 946 err_create_enable_sysfs_entry:
 947         dev_err(&d->dev, "failed to create sysfs attributes");
 948 err_unsupported_chip_id:
 949         kfree(podgov);
 950 err_alloc_podgov:
 951         return -ENOMEM;
 952 }
 953
 954 /*******************************************************************************
 955  * nvhost_pod_exit(struct devfreq *df)
 956  *
 957  * Clean up governor data structures
 958  ******************************************************************************/
 959
 960 static void nvhost_pod_exit(struct devfreq *df)
 961 {
 962         struct podgov_info_rec *podgov = df->data;
 963
 964 #ifdef CONFIG_TEGRA_THROUGHPUT
 965         blocking_notifier_chain_unregister(&throughput_notifier_list,
 966                                            &podgov->throughput_hint_notifier);
 967 #endif
 968         cancel_delayed_work(&podgov->idle_timer);
 969
 970         sysfs_remove_file(&df->dev.parent->kobj, &podgov->user_attr.attr);
 971         sysfs_remove_file(&df->dev.parent->kobj,
 972                           &podgov->freq_request_attr.attr);
 973         sysfs_remove_file(&df->dev.parent->kobj,
 974                           &podgov->enable_3d_scaling_attr.attr);
 975
 976         nvhost_scale3d_debug_deinit(df);
 977
 978         kfree(podgov);
 979 }
 980
 981 static int nvhost_pod_event_handler(struct devfreq *df,
 982                         unsigned int event, void *data)
 983 {
 984         int ret = 0;
 985
 986         switch (event) {
 987         case DEVFREQ_GOV_START:
 988                 ret = nvhost_pod_init(df);
 989                 break;
 990         case DEVFREQ_GOV_STOP:
 991                 nvhost_pod_exit(df);
 992                 break;
 993         case DEVFREQ_GOV_SUSPEND:
 994                 nvhost_pod_suspend(df);
 995                 break;
 996         default:
 997                 break;
 998         }
 999
1000         return ret;
1001 }
1002
1003 static struct devfreq_governor nvhost_podgov = {
1004         .name = "nvhost_podgov",
1005         .get_target_freq = nvhost_pod_estimate_freq,
1006         .event_handler = nvhost_pod_event_handler,
1007 };
1008
1009
1010 static int __init podgov_init(void)
1011 {
1012         return devfreq_add_governor(&nvhost_podgov);
1013 }
1014
1015 static void __exit podgov_exit(void)
1016 {
1017         devfreq_remove_governor(&nvhost_podgov);
1018 }
1019
1020 /* governor must be registered before initialising client devices */
1021 rootfs_initcall(podgov_init);
1022 module_exit(podgov_exit);
1023