drivers/thermal/intel_powerclamp.c

   1 /*
   2  * intel_powerclamp.c - package c-state idle injection
   3  *
   4  * Copyright (c) 2012, Intel Corporation.
   5  *
   6  * Authors:
   7  *     Arjan van de Ven <arjan@linux.intel.com>
   8  *     Jacob Pan <jacob.jun.pan@linux.intel.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms and conditions of the GNU General Public License,
  12  * version 2, as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  17  * more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along with
  20  * this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  22  *
  23  *
  24  *      TODO:
  25  *           1. better handle wakeup from external interrupts, currently a fixed
  26  *              compensation is added to clamping duration when excessive amount
  27  *              of wakeups are observed during idle time. the reason is that in
  28  *              case of external interrupts without need for ack, clamping down
  29  *              cpu in non-irq context does not reduce irq. for majority of the
  30  *              cases, clamping down cpu does help reduce irq as well, we should
  31  *              be able to differenciate the two cases and give a quantitative
  32  *              solution for the irqs that we can control. perhaps based on
  33  *              get_cpu_iowait_time_us()
  34  *
  35  *           2. synchronization with other hw blocks
  36  *
  37  *
  38  */
  39
  40 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  41
  42 #include <linux/module.h>
  43 #include <linux/kernel.h>
  44 #include <linux/delay.h>
  45 #include <linux/kthread.h>
  46 #include <linux/freezer.h>
  47 #include <linux/cpu.h>
  48 #include <linux/thermal.h>
  49 #include <linux/slab.h>
  50 #include <linux/tick.h>
  51 #include <linux/debugfs.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/sched/rt.h>
  54
  55 #include <asm/nmi.h>
  56 #include <asm/msr.h>
  57 #include <asm/mwait.h>
  58 #include <asm/cpu_device_id.h>
  59 #include <asm/idle.h>
  60 #include <asm/hardirq.h>
  61
  62 #define MAX_TARGET_RATIO (50U)
  63 /* For each undisturbed clamping period (no extra wake ups during idle time),
  64  * we increment the confidence counter for the given target ratio.
  65  * CONFIDENCE_OK defines the level where runtime calibration results are
  66  * valid.
  67  */
  68 #define CONFIDENCE_OK (3)
  69 /* Default idle injection duration, driver adjust sleep time to meet target
  70  * idle ratio. Similar to frequency modulation.
  71  */
  72 #define DEFAULT_DURATION_JIFFIES (6)
  73
  74 static unsigned int target_mwait;
  75 static struct dentry *debug_dir;
  76
  77 /* user selected target */
  78 static unsigned int set_target_ratio;
  79 static unsigned int current_ratio;
  80 static bool should_skip;
  81 static bool reduce_irq;
  82 static atomic_t idle_wakeup_counter;
  83 static unsigned int control_cpu; /* The cpu assigned to collect stat and update
  84                                   * control parameters. default to BSP but BSP
  85                                   * can be offlined.
  86                                   */
  87 static bool clamping;
  88
  89
  90 static struct task_struct * __percpu *powerclamp_thread;
  91 static struct thermal_cooling_device *cooling_dev;
  92 static unsigned long *cpu_clamping_mask;  /* bit map for tracking per cpu
  93                                            * clamping thread
  94                                            */
  95
  96 static unsigned int duration;
  97 static unsigned int pkg_cstate_ratio_cur;
  98 static unsigned int window_size;
  99
 100 static int duration_set(const char *arg, const struct kernel_param *kp)
 101 {
 102         int ret = 0;
 103         unsigned long new_duration;
 104
 105         ret = kstrtoul(arg, 10, &new_duration);
 106         if (ret)
 107                 goto exit;
 108         if (new_duration > 25 || new_duration < 6) {
 109                 pr_err("Out of recommended range %lu, between 6-25ms\n",
 110                         new_duration);
 111                 ret = -EINVAL;
 112         }
 113
 114         duration = clamp(new_duration, 6ul, 25ul);
 115         smp_mb();
 116
 117 exit:
 118
 119         return ret;
 120 }
 121
 122 static struct kernel_param_ops duration_ops = {
 123         .set = duration_set,
 124         .get = param_get_int,
 125 };
 126
 127
 128 module_param_cb(duration, &duration_ops, &duration, 0644);
 129 MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec.");
 130
 131 struct powerclamp_calibration_data {
 132         unsigned long confidence;  /* used for calibration, basically a counter
 133                                     * gets incremented each time a clamping
 134                                     * period is completed without extra wakeups
 135                                     * once that counter is reached given level,
 136                                     * compensation is deemed usable.
 137                                     */
 138         unsigned long steady_comp; /* steady state compensation used when
 139                                     * no extra wakeups occurred.
 140                                     */
 141         unsigned long dynamic_comp; /* compensate excessive wakeup from idle
 142                                      * mostly from external interrupts.
 143                                      */
 144 };
 145
 146 static struct powerclamp_calibration_data cal_data[MAX_TARGET_RATIO];
 147
 148 static int window_size_set(const char *arg, const struct kernel_param *kp)
 149 {
 150         int ret = 0;
 151         unsigned long new_window_size;
 152
 153         ret = kstrtoul(arg, 10, &new_window_size);
 154         if (ret)
 155                 goto exit_win;
 156         if (new_window_size > 10 || new_window_size < 2) {
 157                 pr_err("Out of recommended window size %lu, between 2-10\n",
 158                         new_window_size);
 159                 ret = -EINVAL;
 160         }
 161
 162         window_size = clamp(new_window_size, 2ul, 10ul);
 163         smp_mb();
 164
 165 exit_win:
 166
 167         return ret;
 168 }
 169
 170 static struct kernel_param_ops window_size_ops = {
 171         .set = window_size_set,
 172         .get = param_get_int,
 173 };
 174
 175 module_param_cb(window_size, &window_size_ops, &window_size, 0644);
 176 MODULE_PARM_DESC(window_size, "sliding window in number of clamping cycles\n"
 177         "\tpowerclamp controls idle ratio within this window. larger\n"
 178         "\twindow size results in slower response time but more smooth\n"
 179         "\tclamping results. default to 2.");
 180
 181 static void find_target_mwait(void)
 182 {
 183         unsigned int eax, ebx, ecx, edx;
 184         unsigned int highest_cstate = 0;
 185         unsigned int highest_subcstate = 0;
 186         int i;
 187
 188         if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
 189                 return;
 190
 191         cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
 192
 193         if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
 194             !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
 195                 return;
 196
 197         edx >>= MWAIT_SUBSTATE_SIZE;
 198         for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
 199                 if (edx & MWAIT_SUBSTATE_MASK) {
 200                         highest_cstate = i;
 201                         highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
 202                 }
 203         }
 204         target_mwait = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
 205                 (highest_subcstate - 1);
 206
 207 }
 208
 209 static u64 pkg_state_counter(void)
 210 {
 211         u64 val;
 212         u64 count = 0;
 213
 214         static bool skip_c2;
 215         static bool skip_c3;
 216         static bool skip_c6;
 217         static bool skip_c7;
 218
 219         if (!skip_c2) {
 220                 if (!rdmsrl_safe(MSR_PKG_C2_RESIDENCY, &val))
 221                         count += val;
 222                 else
 223                         skip_c2 = true;
 224         }
 225
 226         if (!skip_c3) {
 227                 if (!rdmsrl_safe(MSR_PKG_C3_RESIDENCY, &val))
 228                         count += val;
 229                 else
 230                         skip_c3 = true;
 231         }
 232
 233         if (!skip_c6) {
 234                 if (!rdmsrl_safe(MSR_PKG_C6_RESIDENCY, &val))
 235                         count += val;
 236                 else
 237                         skip_c6 = true;
 238         }
 239
 240         if (!skip_c7) {
 241                 if (!rdmsrl_safe(MSR_PKG_C7_RESIDENCY, &val))
 242                         count += val;
 243                 else
 244                         skip_c7 = true;
 245         }
 246
 247         return count;
 248 }
 249
 250 static void noop_timer(unsigned long foo)
 251 {
 252         /* empty... just the fact that we get the interrupt wakes us up */
 253 }
 254
 255 static unsigned int get_compensation(int ratio)
 256 {
 257         unsigned int comp = 0;
 258
 259         /* we only use compensation if all adjacent ones are good */
 260         if (ratio == 1 &&
 261                 cal_data[ratio].confidence >= CONFIDENCE_OK &&
 262                 cal_data[ratio + 1].confidence >= CONFIDENCE_OK &&
 263                 cal_data[ratio + 2].confidence >= CONFIDENCE_OK) {
 264                 comp = (cal_data[ratio].steady_comp +
 265                         cal_data[ratio + 1].steady_comp +
 266                         cal_data[ratio + 2].steady_comp) / 3;
 267         } else if (ratio == MAX_TARGET_RATIO - 1 &&
 268                 cal_data[ratio].confidence >= CONFIDENCE_OK &&
 269                 cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
 270                 cal_data[ratio - 2].confidence >= CONFIDENCE_OK) {
 271                 comp = (cal_data[ratio].steady_comp +
 272                         cal_data[ratio - 1].steady_comp +
 273                         cal_data[ratio - 2].steady_comp) / 3;
 274         } else if (cal_data[ratio].confidence >= CONFIDENCE_OK &&
 275                 cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
 276                 cal_data[ratio + 1].confidence >= CONFIDENCE_OK) {
 277                 comp = (cal_data[ratio].steady_comp +
 278                         cal_data[ratio - 1].steady_comp +
 279                         cal_data[ratio + 1].steady_comp) / 3;
 280         }
 281
 282         /* REVISIT: simple penalty of double idle injection */
 283         if (reduce_irq)
 284                 comp = ratio;
 285         /* do not exceed limit */
 286         if (comp + ratio >= MAX_TARGET_RATIO)
 287                 comp = MAX_TARGET_RATIO - ratio - 1;
 288
 289         return comp;
 290 }
 291
 292 static void adjust_compensation(int target_ratio, unsigned int win)
 293 {
 294         int delta;
 295         struct powerclamp_calibration_data *d = &cal_data[target_ratio];
 296
 297         /*
 298          * adjust compensations if confidence level has not been reached or
 299          * there are too many wakeups during the last idle injection period, we
 300          * cannot trust the data for compensation.
 301          */
 302         if (d->confidence >= CONFIDENCE_OK ||
 303                 atomic_read(&idle_wakeup_counter) >
 304                 win * num_online_cpus())
 305                 return;
 306
 307         delta = set_target_ratio - current_ratio;
 308         /* filter out bad data */
 309         if (delta >= 0 && delta <= (1+target_ratio/10)) {
 310                 if (d->steady_comp)
 311                         d->steady_comp =
 312                                 roundup(delta+d->steady_comp, 2)/2;
 313                 else
 314                         d->steady_comp = delta;
 315                 d->confidence++;
 316         }
 317 }
 318
 319 static bool powerclamp_adjust_controls(unsigned int target_ratio,
 320                                 unsigned int guard, unsigned int win)
 321 {
 322         static u64 msr_last, tsc_last;
 323         u64 msr_now, tsc_now;
 324         u64 val64;
 325
 326         /* check result for the last window */
 327         msr_now = pkg_state_counter();
 328         rdtscll(tsc_now);
 329
 330         /* calculate pkg cstate vs tsc ratio */
 331         if (!msr_last || !tsc_last)
 332                 current_ratio = 1;
 333         else if (tsc_now-tsc_last) {
 334                 val64 = 100*(msr_now-msr_last);
 335                 do_div(val64, (tsc_now-tsc_last));
 336                 current_ratio = val64;
 337         }
 338
 339         /* update record */
 340         msr_last = msr_now;
 341         tsc_last = tsc_now;
 342
 343         adjust_compensation(target_ratio, win);
 344         /*
 345          * too many external interrupts, set flag such
 346          * that we can take measure later.
 347          */
 348         reduce_irq = atomic_read(&idle_wakeup_counter) >=
 349                 2 * win * num_online_cpus();
 350
 351         atomic_set(&idle_wakeup_counter, 0);
 352         /* if we are above target+guard, skip */
 353         return set_target_ratio + guard <= current_ratio;
 354 }
 355
 356 static int clamp_thread(void *arg)
 357 {
 358         int cpunr = (unsigned long)arg;
 359         DEFINE_TIMER(wakeup_timer, noop_timer, 0, 0);
 360         static const struct sched_param param = {
 361                 .sched_priority = MAX_USER_RT_PRIO/2,
 362         };
 363         unsigned int count = 0;
 364         unsigned int target_ratio;
 365
 366         set_bit(cpunr, cpu_clamping_mask);
 367         set_freezable();
 368         init_timer_on_stack(&wakeup_timer);
 369         sched_setscheduler(current, SCHED_FIFO, &param);
 370
 371         while (true == clamping && !kthread_should_stop() &&
 372                 cpu_online(cpunr)) {
 373                 int sleeptime;
 374                 unsigned long target_jiffies;
 375                 unsigned int guard;
 376                 unsigned int compensation = 0;
 377                 int interval; /* jiffies to sleep for each attempt */
 378                 unsigned int duration_jiffies = msecs_to_jiffies(duration);
 379                 unsigned int window_size_now;
 380
 381                 try_to_freeze();
 382                 /*
 383                  * make sure user selected ratio does not take effect until
 384                  * the next round. adjust target_ratio if user has changed
 385                  * target such that we can converge quickly.
 386                  */
 387                 target_ratio = set_target_ratio;
 388                 guard = 1 + target_ratio/20;
 389                 window_size_now = window_size;
 390                 count++;
 391
 392                 /*
 393                  * systems may have different ability to enter package level
 394                  * c-states, thus we need to compensate the injected idle ratio
 395                  * to achieve the actual target reported by the HW.
 396                  */
 397                 compensation = get_compensation(target_ratio);
 398                 interval = duration_jiffies*100/(target_ratio+compensation);
 399
 400                 /* align idle time */
 401                 target_jiffies = roundup(jiffies, interval);
 402                 sleeptime = target_jiffies - jiffies;
 403                 if (sleeptime <= 0)
 404                         sleeptime = 1;
 405                 schedule_timeout_interruptible(sleeptime);
 406                 /*
 407                  * only elected controlling cpu can collect stats and update
 408                  * control parameters.
 409                  */
 410                 if (cpunr == control_cpu && !(count%window_size_now)) {
 411                         should_skip =
 412                                 powerclamp_adjust_controls(target_ratio,
 413                                                         guard, window_size_now);
 414                         smp_mb();
 415                 }
 416
 417                 if (should_skip)
 418                         continue;
 419
 420                 target_jiffies = jiffies + duration_jiffies;
 421                 mod_timer(&wakeup_timer, target_jiffies);
 422                 if (unlikely(local_softirq_pending()))
 423                         continue;
 424                 /*
 425                  * stop tick sched during idle time, interrupts are still
 426                  * allowed. thus jiffies are updated properly.
 427                  */
 428                 preempt_disable();
 429                 tick_nohz_idle_enter();
 430                 /* mwait until target jiffies is reached */
 431                 while (time_before(jiffies, target_jiffies)) {
 432                         unsigned long ecx = 1;
 433                         unsigned long eax = target_mwait;
 434
 435                         /*
 436                          * REVISIT: may call enter_idle() to notify drivers who
 437                          * can save power during cpu idle. same for exit_idle()
 438                          */
 439                         local_touch_nmi();
 440                         stop_critical_timings();
 441                         __monitor((void *)&current_thread_info()->flags, 0, 0);
 442                         cpu_relax(); /* allow HT sibling to run */
 443                         __mwait(eax, ecx);
 444                         start_critical_timings();
 445                         atomic_inc(&idle_wakeup_counter);
 446                 }
 447                 tick_nohz_idle_exit();
 448                 preempt_enable_no_resched();
 449         }
 450         del_timer_sync(&wakeup_timer);
 451         clear_bit(cpunr, cpu_clamping_mask);
 452
 453         return 0;
 454 }
 455
 456 /*
 457  * 1 HZ polling while clamping is active, useful for userspace
 458  * to monitor actual idle ratio.
 459  */
 460 static void poll_pkg_cstate(struct work_struct *dummy);
 461 static DECLARE_DELAYED_WORK(poll_pkg_cstate_work, poll_pkg_cstate);
 462 static void poll_pkg_cstate(struct work_struct *dummy)
 463 {
 464         static u64 msr_last;
 465         static u64 tsc_last;
 466         static unsigned long jiffies_last;
 467
 468         u64 msr_now;
 469         unsigned long jiffies_now;
 470         u64 tsc_now;
 471         u64 val64;
 472
 473         msr_now = pkg_state_counter();
 474         rdtscll(tsc_now);
 475         jiffies_now = jiffies;
 476
 477         /* calculate pkg cstate vs tsc ratio */
 478         if (!msr_last || !tsc_last)
 479                 pkg_cstate_ratio_cur = 1;
 480         else {
 481                 if (tsc_now - tsc_last) {
 482                         val64 = 100 * (msr_now - msr_last);
 483                         do_div(val64, (tsc_now - tsc_last));
 484                         pkg_cstate_ratio_cur = val64;
 485                 }
 486         }
 487
 488         /* update record */
 489         msr_last = msr_now;
 490         jiffies_last = jiffies_now;
 491         tsc_last = tsc_now;
 492
 493         if (true == clamping)
 494                 schedule_delayed_work(&poll_pkg_cstate_work, HZ);
 495 }
 496
 497 static int start_power_clamp(void)
 498 {
 499         unsigned long cpu;
 500         struct task_struct *thread;
 501
 502         /* check if pkg cstate counter is completely 0, abort in this case */
 503         if (!pkg_state_counter()) {
 504                 pr_err("pkg cstate counter not functional, abort\n");
 505                 return -EINVAL;
 506         }
 507
 508         set_target_ratio = clamp(set_target_ratio, 0U, MAX_TARGET_RATIO - 1);
 509         /* prevent cpu hotplug */
 510         get_online_cpus();
 511
 512         /* prefer BSP */
 513         control_cpu = 0;
 514         if (!cpu_online(control_cpu))
 515                 control_cpu = smp_processor_id();
 516
 517         clamping = true;
 518         schedule_delayed_work(&poll_pkg_cstate_work, 0);
 519
 520         /* start one thread per online cpu */
 521         for_each_online_cpu(cpu) {
 522                 struct task_struct **p =
 523                         per_cpu_ptr(powerclamp_thread, cpu);
 524
 525                 thread = kthread_create_on_node(clamp_thread,
 526                                                 (void *) cpu,
 527                                                 cpu_to_node(cpu),
 528                                                 "kidle_inject/%ld", cpu);
 529                 /* bind to cpu here */
 530                 if (likely(!IS_ERR(thread))) {
 531                         kthread_bind(thread, cpu);
 532                         wake_up_process(thread);
 533                         *p = thread;
 534                 }
 535
 536         }
 537         put_online_cpus();
 538
 539         return 0;
 540 }
 541
 542 static void end_power_clamp(void)
 543 {
 544         int i;
 545         struct task_struct *thread;
 546
 547         clamping = false;
 548         /*
 549          * make clamping visible to other cpus and give per cpu clamping threads
 550          * sometime to exit, or gets killed later.
 551          */
 552         smp_mb();
 553         msleep(20);
 554         if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) {
 555                 for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) {
 556                         pr_debug("clamping thread for cpu %d alive, kill\n", i);
 557                         thread = *per_cpu_ptr(powerclamp_thread, i);
 558                         kthread_stop(thread);
 559                 }
 560         }
 561 }
 562
 563 static int powerclamp_cpu_callback(struct notifier_block *nfb,
 564                                 unsigned long action, void *hcpu)
 565 {
 566         unsigned long cpu = (unsigned long)hcpu;
 567         struct task_struct *thread;
 568         struct task_struct **percpu_thread =
 569                 per_cpu_ptr(powerclamp_thread, cpu);
 570
 571         if (false == clamping)
 572                 goto exit_ok;
 573
 574         switch (action) {
 575         case CPU_ONLINE:
 576                 thread = kthread_create_on_node(clamp_thread,
 577                                                 (void *) cpu,
 578                                                 cpu_to_node(cpu),
 579                                                 "kidle_inject/%lu", cpu);
 580                 if (likely(!IS_ERR(thread))) {
 581                         kthread_bind(thread, cpu);
 582                         wake_up_process(thread);
 583                         *percpu_thread = thread;
 584                 }
 585                 /* prefer BSP as controlling CPU */
 586                 if (cpu == 0) {
 587                         control_cpu = 0;
 588                         smp_mb();
 589                 }
 590                 break;
 591         case CPU_DEAD:
 592                 if (test_bit(cpu, cpu_clamping_mask)) {
 593                         pr_err("cpu %lu dead but powerclamping thread is not\n",
 594                                 cpu);
 595                         kthread_stop(*percpu_thread);
 596                 }
 597                 if (cpu == control_cpu) {
 598                         control_cpu = smp_processor_id();
 599                         smp_mb();
 600                 }
 601         }
 602
 603 exit_ok:
 604         return NOTIFY_OK;
 605 }
 606
 607 static struct notifier_block powerclamp_cpu_notifier = {
 608         .notifier_call = powerclamp_cpu_callback,
 609 };
 610
 611 static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,
 612                                  unsigned long *state)
 613 {
 614         *state = MAX_TARGET_RATIO;
 615
 616         return 0;
 617 }
 618
 619 static int powerclamp_get_cur_state(struct thermal_cooling_device *cdev,
 620                                  unsigned long *state)
 621 {
 622         if (true == clamping)
 623                 *state = pkg_cstate_ratio_cur;
 624         else
 625                 /* to save power, do not poll idle ratio while not clamping */
 626                 *state = -1; /* indicates invalid state */
 627
 628         return 0;
 629 }
 630
 631 static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev,
 632                                  unsigned long new_target_ratio)
 633 {
 634         int ret = 0;
 635
 636         new_target_ratio = clamp(new_target_ratio, 0UL,
 637                                 (unsigned long) (MAX_TARGET_RATIO-1));
 638         if (set_target_ratio == 0 && new_target_ratio > 0) {
 639                 pr_info("Start idle injection to reduce power\n");
 640                 set_target_ratio = new_target_ratio;
 641                 ret = start_power_clamp();
 642                 goto exit_set;
 643         } else  if (set_target_ratio > 0 && new_target_ratio == 0) {
 644                 pr_info("Stop forced idle injection\n");
 645                 set_target_ratio = 0;
 646                 end_power_clamp();
 647         } else  /* adjust currently running */ {
 648                 set_target_ratio = new_target_ratio;
 649                 /* make new set_target_ratio visible to other cpus */
 650                 smp_mb();
 651         }
 652
 653 exit_set:
 654         return ret;
 655 }
 656
 657 /* bind to generic thermal layer as cooling device*/
 658 static struct thermal_cooling_device_ops powerclamp_cooling_ops = {
 659         .get_max_state = powerclamp_get_max_state,
 660         .get_cur_state = powerclamp_get_cur_state,
 661         .set_cur_state = powerclamp_set_cur_state,
 662 };
 663
 664 /* runs on Nehalem and later */
 665 static const struct x86_cpu_id intel_powerclamp_ids[] = {
 666         { X86_VENDOR_INTEL, 6, 0x1a},
 667         { X86_VENDOR_INTEL, 6, 0x1c},
 668         { X86_VENDOR_INTEL, 6, 0x1e},
 669         { X86_VENDOR_INTEL, 6, 0x1f},
 670         { X86_VENDOR_INTEL, 6, 0x25},
 671         { X86_VENDOR_INTEL, 6, 0x26},
 672         { X86_VENDOR_INTEL, 6, 0x2a},
 673         { X86_VENDOR_INTEL, 6, 0x2c},
 674         { X86_VENDOR_INTEL, 6, 0x2d},
 675         { X86_VENDOR_INTEL, 6, 0x2e},
 676         { X86_VENDOR_INTEL, 6, 0x2f},
 677         { X86_VENDOR_INTEL, 6, 0x3a},
 678         {}
 679 };
 680 MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
 681
 682 static int powerclamp_probe(void)
 683 {
 684         if (!x86_match_cpu(intel_powerclamp_ids)) {
 685                 pr_err("Intel powerclamp does not run on family %d model %d\n",
 686                                 boot_cpu_data.x86, boot_cpu_data.x86_model);
 687                 return -ENODEV;
 688         }
 689         if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||
 690                 !boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ||
 691                 !boot_cpu_has(X86_FEATURE_MWAIT) ||
 692                 !boot_cpu_has(X86_FEATURE_ARAT))
 693                 return -ENODEV;
 694
 695         /* find the deepest mwait value */
 696         find_target_mwait();
 697
 698         return 0;
 699 }
 700
 701 static int powerclamp_debug_show(struct seq_file *m, void *unused)
 702 {
 703         int i = 0;
 704
 705         seq_printf(m, "controlling cpu: %d\n", control_cpu);
 706         seq_printf(m, "pct confidence steady dynamic (compensation)\n");
 707         for (i = 0; i < MAX_TARGET_RATIO; i++) {
 708                 seq_printf(m, "%d\t%lu\t%lu\t%lu\n",
 709                         i,
 710                         cal_data[i].confidence,
 711                         cal_data[i].steady_comp,
 712                         cal_data[i].dynamic_comp);
 713         }
 714
 715         return 0;
 716 }
 717
 718 static int powerclamp_debug_open(struct inode *inode,
 719                         struct file *file)
 720 {
 721         return single_open(file, powerclamp_debug_show, inode->i_private);
 722 }
 723
 724 static const struct file_operations powerclamp_debug_fops = {
 725         .open           = powerclamp_debug_open,
 726         .read           = seq_read,
 727         .llseek         = seq_lseek,
 728         .release        = single_release,
 729         .owner          = THIS_MODULE,
 730 };
 731
 732 static inline void powerclamp_create_debug_files(void)
 733 {
 734         debug_dir = debugfs_create_dir("intel_powerclamp", NULL);
 735         if (!debug_dir)
 736                 return;
 737
 738         if (!debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir,
 739                                         cal_data, &powerclamp_debug_fops))
 740                 goto file_error;
 741
 742         return;
 743
 744 file_error:
 745         debugfs_remove_recursive(debug_dir);
 746 }
 747
 748 static int powerclamp_init(void)
 749 {
 750         int retval;
 751         int bitmap_size;
 752
 753         bitmap_size = BITS_TO_LONGS(num_possible_cpus()) * sizeof(long);
 754         cpu_clamping_mask = kzalloc(bitmap_size, GFP_KERNEL);
 755         if (!cpu_clamping_mask)
 756                 return -ENOMEM;
 757
 758         /* probe cpu features and ids here */
 759         retval = powerclamp_probe();
 760         if (retval)
 761                 return retval;
 762         /* set default limit, maybe adjusted during runtime based on feedback */
 763         window_size = 2;
 764         register_hotcpu_notifier(&powerclamp_cpu_notifier);
 765         powerclamp_thread = alloc_percpu(struct task_struct *);
 766         cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL,
 767                                                 &powerclamp_cooling_ops);
 768         if (IS_ERR(cooling_dev))
 769                 return -ENODEV;
 770
 771         if (!duration)
 772                 duration = jiffies_to_msecs(DEFAULT_DURATION_JIFFIES);
 773         powerclamp_create_debug_files();
 774
 775         return 0;
 776 }
 777 module_init(powerclamp_init);
 778
 779 static void powerclamp_exit(void)
 780 {
 781         unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
 782         end_power_clamp();
 783         free_percpu(powerclamp_thread);
 784         thermal_cooling_device_unregister(cooling_dev);
 785         kfree(cpu_clamping_mask);
 786
 787         cancel_delayed_work_sync(&poll_pkg_cstate_work);
 788         debugfs_remove_recursive(debug_dir);
 789 }
 790 module_exit(powerclamp_exit);
 791
 792 MODULE_LICENSE("GPL");
 793 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
 794 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
 795 MODULE_DESCRIPTION("Package Level C-state Idle Injection for Intel CPUs");