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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
74static unsigned int target_mwait;
75static struct dentry *debug_dir;
76
77/* user selected target */
78static unsigned int set_target_ratio;
79static unsigned int current_ratio;
80static bool should_skip;
81static bool reduce_irq;
82static atomic_t idle_wakeup_counter;
83static 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 */
87static bool clamping;
88
89
90static struct task_struct * __percpu *powerclamp_thread;
91static struct thermal_cooling_device *cooling_dev;
92static unsigned long *cpu_clamping_mask; /* bit map for tracking per cpu
93 * clamping thread
94 */
95
96static unsigned int duration;
97static unsigned int pkg_cstate_ratio_cur;
98static unsigned int window_size;
99
100static 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
117exit:
118
119 return ret;
120}
121
122static const struct kernel_param_ops duration_ops = {
123 .set = duration_set,
124 .get = param_get_int,
125};
126
127
128module_param_cb(duration, &duration_ops, &duration, 0644);
129MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec.");
130
131struct 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
146static struct powerclamp_calibration_data cal_data[MAX_TARGET_RATIO];
147
148static 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
165exit_win:
166
167 return ret;
168}
169
170static const struct kernel_param_ops window_size_ops = {
171 .set = window_size_set,
172 .get = param_get_int,
173};
174
175module_param_cb(window_size, &window_size_ops, &window_size, 0644);
176MODULE_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
181static 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
209struct pkg_cstate_info {
210 bool skip;
211 int msr_index;
212 int cstate_id;
213};
214
215#define PKG_CSTATE_INIT(id) { \
216 .msr_index = MSR_PKG_C##id##_RESIDENCY, \
217 .cstate_id = id \
218 }
219
220static struct pkg_cstate_info pkg_cstates[] = {
221 PKG_CSTATE_INIT(2),
222 PKG_CSTATE_INIT(3),
223 PKG_CSTATE_INIT(6),
224 PKG_CSTATE_INIT(7),
225 PKG_CSTATE_INIT(8),
226 PKG_CSTATE_INIT(9),
227 PKG_CSTATE_INIT(10),
228 {NULL},
229};
230
231static bool has_pkg_state_counter(void)
232{
233 u64 val;
234 struct pkg_cstate_info *info = pkg_cstates;
235
236 /* check if any one of the counter msrs exists */
237 while (info->msr_index) {
238 if (!rdmsrl_safe(info->msr_index, &val))
239 return true;
240 info++;
241 }
242
243 return false;
244}
245
246static u64 pkg_state_counter(void)
247{
248 u64 val;
249 u64 count = 0;
250 struct pkg_cstate_info *info = pkg_cstates;
251
252 while (info->msr_index) {
253 if (!info->skip) {
254 if (!rdmsrl_safe(info->msr_index, &val))
255 count += val;
256 else
257 info->skip = true;
258 }
259 info++;
260 }
261
262 return count;
263}
264
265static void noop_timer(unsigned long foo)
266{
267 /* empty... just the fact that we get the interrupt wakes us up */
268}
269
270static unsigned int get_compensation(int ratio)
271{
272 unsigned int comp = 0;
273
274 /* we only use compensation if all adjacent ones are good */
275 if (ratio == 1 &&
276 cal_data[ratio].confidence >= CONFIDENCE_OK &&
277 cal_data[ratio + 1].confidence >= CONFIDENCE_OK &&
278 cal_data[ratio + 2].confidence >= CONFIDENCE_OK) {
279 comp = (cal_data[ratio].steady_comp +
280 cal_data[ratio + 1].steady_comp +
281 cal_data[ratio + 2].steady_comp) / 3;
282 } else if (ratio == MAX_TARGET_RATIO - 1 &&
283 cal_data[ratio].confidence >= CONFIDENCE_OK &&
284 cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
285 cal_data[ratio - 2].confidence >= CONFIDENCE_OK) {
286 comp = (cal_data[ratio].steady_comp +
287 cal_data[ratio - 1].steady_comp +
288 cal_data[ratio - 2].steady_comp) / 3;
289 } else if (cal_data[ratio].confidence >= CONFIDENCE_OK &&
290 cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
291 cal_data[ratio + 1].confidence >= CONFIDENCE_OK) {
292 comp = (cal_data[ratio].steady_comp +
293 cal_data[ratio - 1].steady_comp +
294 cal_data[ratio + 1].steady_comp) / 3;
295 }
296
297 /* REVISIT: simple penalty of double idle injection */
298 if (reduce_irq)
299 comp = ratio;
300 /* do not exceed limit */
301 if (comp + ratio >= MAX_TARGET_RATIO)
302 comp = MAX_TARGET_RATIO - ratio - 1;
303
304 return comp;
305}
306
307static void adjust_compensation(int target_ratio, unsigned int win)
308{
309 int delta;
310 struct powerclamp_calibration_data *d = &cal_data[target_ratio];
311
312 /*
313 * adjust compensations if confidence level has not been reached or
314 * there are too many wakeups during the last idle injection period, we
315 * cannot trust the data for compensation.
316 */
317 if (d->confidence >= CONFIDENCE_OK ||
318 atomic_read(&idle_wakeup_counter) >
319 win * num_online_cpus())
320 return;
321
322 delta = set_target_ratio - current_ratio;
323 /* filter out bad data */
324 if (delta >= 0 && delta <= (1+target_ratio/10)) {
325 if (d->steady_comp)
326 d->steady_comp =
327 roundup(delta+d->steady_comp, 2)/2;
328 else
329 d->steady_comp = delta;
330 d->confidence++;
331 }
332}
333
334static bool powerclamp_adjust_controls(unsigned int target_ratio,
335 unsigned int guard, unsigned int win)
336{
337 static u64 msr_last, tsc_last;
338 u64 msr_now, tsc_now;
339 u64 val64;
340
341 /* check result for the last window */
342 msr_now = pkg_state_counter();
343 tsc_now = rdtsc();
344
345 /* calculate pkg cstate vs tsc ratio */
346 if (!msr_last || !tsc_last)
347 current_ratio = 1;
348 else if (tsc_now-tsc_last) {
349 val64 = 100*(msr_now-msr_last);
350 do_div(val64, (tsc_now-tsc_last));
351 current_ratio = val64;
352 }
353
354 /* update record */
355 msr_last = msr_now;
356 tsc_last = tsc_now;
357
358 adjust_compensation(target_ratio, win);
359 /*
360 * too many external interrupts, set flag such
361 * that we can take measure later.
362 */
363 reduce_irq = atomic_read(&idle_wakeup_counter) >=
364 2 * win * num_online_cpus();
365
366 atomic_set(&idle_wakeup_counter, 0);
367 /* if we are above target+guard, skip */
368 return set_target_ratio + guard <= current_ratio;
369}
370
371static int clamp_thread(void *arg)
372{
373 int cpunr = (unsigned long)arg;
374 DEFINE_TIMER(wakeup_timer, noop_timer, 0, 0);
375 static const struct sched_param param = {
376 .sched_priority = MAX_USER_RT_PRIO/2,
377 };
378 unsigned int count = 0;
379 unsigned int target_ratio;
380
381 set_bit(cpunr, cpu_clamping_mask);
382 set_freezable();
383 init_timer_on_stack(&wakeup_timer);
384 sched_setscheduler(current, SCHED_FIFO, ¶m);
385
386 while (true == clamping && !kthread_should_stop() &&
387 cpu_online(cpunr)) {
388 int sleeptime;
389 unsigned long target_jiffies;
390 unsigned int guard;
391 unsigned int compensation = 0;
392 int interval; /* jiffies to sleep for each attempt */
393 unsigned int duration_jiffies = msecs_to_jiffies(duration);
394 unsigned int window_size_now;
395
396 try_to_freeze();
397 /*
398 * make sure user selected ratio does not take effect until
399 * the next round. adjust target_ratio if user has changed
400 * target such that we can converge quickly.
401 */
402 target_ratio = set_target_ratio;
403 guard = 1 + target_ratio/20;
404 window_size_now = window_size;
405 count++;
406
407 /*
408 * systems may have different ability to enter package level
409 * c-states, thus we need to compensate the injected idle ratio
410 * to achieve the actual target reported by the HW.
411 */
412 compensation = get_compensation(target_ratio);
413 interval = duration_jiffies*100/(target_ratio+compensation);
414
415 /* align idle time */
416 target_jiffies = roundup(jiffies, interval);
417 sleeptime = target_jiffies - jiffies;
418 if (sleeptime <= 0)
419 sleeptime = 1;
420 schedule_timeout_interruptible(sleeptime);
421 /*
422 * only elected controlling cpu can collect stats and update
423 * control parameters.
424 */
425 if (cpunr == control_cpu && !(count%window_size_now)) {
426 should_skip =
427 powerclamp_adjust_controls(target_ratio,
428 guard, window_size_now);
429 smp_mb();
430 }
431
432 if (should_skip)
433 continue;
434
435 target_jiffies = jiffies + duration_jiffies;
436 mod_timer(&wakeup_timer, target_jiffies);
437 if (unlikely(local_softirq_pending()))
438 continue;
439 /*
440 * stop tick sched during idle time, interrupts are still
441 * allowed. thus jiffies are updated properly.
442 */
443 preempt_disable();
444 /* mwait until target jiffies is reached */
445 while (time_before(jiffies, target_jiffies)) {
446 unsigned long ecx = 1;
447 unsigned long eax = target_mwait;
448
449 /*
450 * REVISIT: may call enter_idle() to notify drivers who
451 * can save power during cpu idle. same for exit_idle()
452 */
453 local_touch_nmi();
454 stop_critical_timings();
455 mwait_idle_with_hints(eax, ecx);
456 start_critical_timings();
457 atomic_inc(&idle_wakeup_counter);
458 }
459 preempt_enable();
460 }
461 del_timer_sync(&wakeup_timer);
462 clear_bit(cpunr, cpu_clamping_mask);
463
464 return 0;
465}
466
467/*
468 * 1 HZ polling while clamping is active, useful for userspace
469 * to monitor actual idle ratio.
470 */
471static void poll_pkg_cstate(struct work_struct *dummy);
472static DECLARE_DELAYED_WORK(poll_pkg_cstate_work, poll_pkg_cstate);
473static void poll_pkg_cstate(struct work_struct *dummy)
474{
475 static u64 msr_last;
476 static u64 tsc_last;
477 static unsigned long jiffies_last;
478
479 u64 msr_now;
480 unsigned long jiffies_now;
481 u64 tsc_now;
482 u64 val64;
483
484 msr_now = pkg_state_counter();
485 tsc_now = rdtsc();
486 jiffies_now = jiffies;
487
488 /* calculate pkg cstate vs tsc ratio */
489 if (!msr_last || !tsc_last)
490 pkg_cstate_ratio_cur = 1;
491 else {
492 if (tsc_now - tsc_last) {
493 val64 = 100 * (msr_now - msr_last);
494 do_div(val64, (tsc_now - tsc_last));
495 pkg_cstate_ratio_cur = val64;
496 }
497 }
498
499 /* update record */
500 msr_last = msr_now;
501 jiffies_last = jiffies_now;
502 tsc_last = tsc_now;
503
504 if (true == clamping)
505 schedule_delayed_work(&poll_pkg_cstate_work, HZ);
506}
507
508static int start_power_clamp(void)
509{
510 unsigned long cpu;
511 struct task_struct *thread;
512
513 /* check if pkg cstate counter is completely 0, abort in this case */
514 if (!has_pkg_state_counter()) {
515 pr_err("pkg cstate counter not functional, abort\n");
516 return -EINVAL;
517 }
518
519 set_target_ratio = clamp(set_target_ratio, 0U, MAX_TARGET_RATIO - 1);
520 /* prevent cpu hotplug */
521 get_online_cpus();
522
523 /* prefer BSP */
524 control_cpu = 0;
525 if (!cpu_online(control_cpu))
526 control_cpu = smp_processor_id();
527
528 clamping = true;
529 schedule_delayed_work(&poll_pkg_cstate_work, 0);
530
531 /* start one thread per online cpu */
532 for_each_online_cpu(cpu) {
533 struct task_struct **p =
534 per_cpu_ptr(powerclamp_thread, cpu);
535
536 thread = kthread_create_on_node(clamp_thread,
537 (void *) cpu,
538 cpu_to_node(cpu),
539 "kidle_inject/%ld", cpu);
540 /* bind to cpu here */
541 if (likely(!IS_ERR(thread))) {
542 kthread_bind(thread, cpu);
543 wake_up_process(thread);
544 *p = thread;
545 }
546
547 }
548 put_online_cpus();
549
550 return 0;
551}
552
553static void end_power_clamp(void)
554{
555 int i;
556 struct task_struct *thread;
557
558 clamping = false;
559 /*
560 * make clamping visible to other cpus and give per cpu clamping threads
561 * sometime to exit, or gets killed later.
562 */
563 smp_mb();
564 msleep(20);
565 if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) {
566 for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) {
567 pr_debug("clamping thread for cpu %d alive, kill\n", i);
568 thread = *per_cpu_ptr(powerclamp_thread, i);
569 kthread_stop(thread);
570 }
571 }
572}
573
574static int powerclamp_cpu_callback(struct notifier_block *nfb,
575 unsigned long action, void *hcpu)
576{
577 unsigned long cpu = (unsigned long)hcpu;
578 struct task_struct *thread;
579 struct task_struct **percpu_thread =
580 per_cpu_ptr(powerclamp_thread, cpu);
581
582 if (false == clamping)
583 goto exit_ok;
584
585 switch (action) {
586 case CPU_ONLINE:
587 thread = kthread_create_on_node(clamp_thread,
588 (void *) cpu,
589 cpu_to_node(cpu),
590 "kidle_inject/%lu", cpu);
591 if (likely(!IS_ERR(thread))) {
592 kthread_bind(thread, cpu);
593 wake_up_process(thread);
594 *percpu_thread = thread;
595 }
596 /* prefer BSP as controlling CPU */
597 if (cpu == 0) {
598 control_cpu = 0;
599 smp_mb();
600 }
601 break;
602 case CPU_DEAD:
603 if (test_bit(cpu, cpu_clamping_mask)) {
604 pr_err("cpu %lu dead but powerclamping thread is not\n",
605 cpu);
606 kthread_stop(*percpu_thread);
607 }
608 if (cpu == control_cpu) {
609 control_cpu = smp_processor_id();
610 smp_mb();
611 }
612 }
613
614exit_ok:
615 return NOTIFY_OK;
616}
617
618static struct notifier_block powerclamp_cpu_notifier = {
619 .notifier_call = powerclamp_cpu_callback,
620};
621
622static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,
623 unsigned long *state)
624{
625 *state = MAX_TARGET_RATIO;
626
627 return 0;
628}
629
630static int powerclamp_get_cur_state(struct thermal_cooling_device *cdev,
631 unsigned long *state)
632{
633 if (true == clamping)
634 *state = pkg_cstate_ratio_cur;
635 else
636 /* to save power, do not poll idle ratio while not clamping */
637 *state = -1; /* indicates invalid state */
638
639 return 0;
640}
641
642static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev,
643 unsigned long new_target_ratio)
644{
645 int ret = 0;
646
647 new_target_ratio = clamp(new_target_ratio, 0UL,
648 (unsigned long) (MAX_TARGET_RATIO-1));
649 if (set_target_ratio == 0 && new_target_ratio > 0) {
650 pr_info("Start idle injection to reduce power\n");
651 set_target_ratio = new_target_ratio;
652 ret = start_power_clamp();
653 goto exit_set;
654 } else if (set_target_ratio > 0 && new_target_ratio == 0) {
655 pr_info("Stop forced idle injection\n");
656 set_target_ratio = 0;
657 end_power_clamp();
658 } else /* adjust currently running */ {
659 set_target_ratio = new_target_ratio;
660 /* make new set_target_ratio visible to other cpus */
661 smp_mb();
662 }
663
664exit_set:
665 return ret;
666}
667
668/* bind to generic thermal layer as cooling device*/
669static struct thermal_cooling_device_ops powerclamp_cooling_ops = {
670 .get_max_state = powerclamp_get_max_state,
671 .get_cur_state = powerclamp_get_cur_state,
672 .set_cur_state = powerclamp_set_cur_state,
673};
674
675/* runs on Nehalem and later */
676static const struct x86_cpu_id intel_powerclamp_ids[] __initconst = {
677 { X86_VENDOR_INTEL, 6, 0x1a},
678 { X86_VENDOR_INTEL, 6, 0x1c},
679 { X86_VENDOR_INTEL, 6, 0x1e},
680 { X86_VENDOR_INTEL, 6, 0x1f},
681 { X86_VENDOR_INTEL, 6, 0x25},
682 { X86_VENDOR_INTEL, 6, 0x26},
683 { X86_VENDOR_INTEL, 6, 0x2a},
684 { X86_VENDOR_INTEL, 6, 0x2c},
685 { X86_VENDOR_INTEL, 6, 0x2d},
686 { X86_VENDOR_INTEL, 6, 0x2e},
687 { X86_VENDOR_INTEL, 6, 0x2f},
688 { X86_VENDOR_INTEL, 6, 0x37},
689 { X86_VENDOR_INTEL, 6, 0x3a},
690 { X86_VENDOR_INTEL, 6, 0x3c},
691 { X86_VENDOR_INTEL, 6, 0x3d},
692 { X86_VENDOR_INTEL, 6, 0x3e},
693 { X86_VENDOR_INTEL, 6, 0x3f},
694 { X86_VENDOR_INTEL, 6, 0x45},
695 { X86_VENDOR_INTEL, 6, 0x46},
696 { X86_VENDOR_INTEL, 6, 0x47},
697 { X86_VENDOR_INTEL, 6, 0x4c},
698 { X86_VENDOR_INTEL, 6, 0x4d},
699 { X86_VENDOR_INTEL, 6, 0x4e},
700 { X86_VENDOR_INTEL, 6, 0x4f},
701 { X86_VENDOR_INTEL, 6, 0x56},
702 { X86_VENDOR_INTEL, 6, 0x57},
703 { X86_VENDOR_INTEL, 6, 0x5e},
704 {}
705};
706MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
707
708static int __init powerclamp_probe(void)
709{
710 if (!x86_match_cpu(intel_powerclamp_ids)) {
711 pr_err("Intel powerclamp does not run on family %d model %d\n",
712 boot_cpu_data.x86, boot_cpu_data.x86_model);
713 return -ENODEV;
714 }
715 if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||
716 !boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ||
717 !boot_cpu_has(X86_FEATURE_MWAIT) ||
718 !boot_cpu_has(X86_FEATURE_ARAT))
719 return -ENODEV;
720
721 /* find the deepest mwait value */
722 find_target_mwait();
723
724 return 0;
725}
726
727static int powerclamp_debug_show(struct seq_file *m, void *unused)
728{
729 int i = 0;
730
731 seq_printf(m, "controlling cpu: %d\n", control_cpu);
732 seq_printf(m, "pct confidence steady dynamic (compensation)\n");
733 for (i = 0; i < MAX_TARGET_RATIO; i++) {
734 seq_printf(m, "%d\t%lu\t%lu\t%lu\n",
735 i,
736 cal_data[i].confidence,
737 cal_data[i].steady_comp,
738 cal_data[i].dynamic_comp);
739 }
740
741 return 0;
742}
743
744static int powerclamp_debug_open(struct inode *inode,
745 struct file *file)
746{
747 return single_open(file, powerclamp_debug_show, inode->i_private);
748}
749
750static const struct file_operations powerclamp_debug_fops = {
751 .open = powerclamp_debug_open,
752 .read = seq_read,
753 .llseek = seq_lseek,
754 .release = single_release,
755 .owner = THIS_MODULE,
756};
757
758static inline void powerclamp_create_debug_files(void)
759{
760 debug_dir = debugfs_create_dir("intel_powerclamp", NULL);
761 if (!debug_dir)
762 return;
763
764 if (!debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir,
765 cal_data, &powerclamp_debug_fops))
766 goto file_error;
767
768 return;
769
770file_error:
771 debugfs_remove_recursive(debug_dir);
772}
773
774static int __init powerclamp_init(void)
775{
776 int retval;
777 int bitmap_size;
778
779 bitmap_size = BITS_TO_LONGS(num_possible_cpus()) * sizeof(long);
780 cpu_clamping_mask = kzalloc(bitmap_size, GFP_KERNEL);
781 if (!cpu_clamping_mask)
782 return -ENOMEM;
783
784 /* probe cpu features and ids here */
785 retval = powerclamp_probe();
786 if (retval)
787 goto exit_free;
788
789 /* set default limit, maybe adjusted during runtime based on feedback */
790 window_size = 2;
791 register_hotcpu_notifier(&powerclamp_cpu_notifier);
792
793 powerclamp_thread = alloc_percpu(struct task_struct *);
794 if (!powerclamp_thread) {
795 retval = -ENOMEM;
796 goto exit_unregister;
797 }
798
799 cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL,
800 &powerclamp_cooling_ops);
801 if (IS_ERR(cooling_dev)) {
802 retval = -ENODEV;
803 goto exit_free_thread;
804 }
805
806 if (!duration)
807 duration = jiffies_to_msecs(DEFAULT_DURATION_JIFFIES);
808
809 powerclamp_create_debug_files();
810
811 return 0;
812
813exit_free_thread:
814 free_percpu(powerclamp_thread);
815exit_unregister:
816 unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
817exit_free:
818 kfree(cpu_clamping_mask);
819 return retval;
820}
821module_init(powerclamp_init);
822
823static void __exit powerclamp_exit(void)
824{
825 unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
826 end_power_clamp();
827 free_percpu(powerclamp_thread);
828 thermal_cooling_device_unregister(cooling_dev);
829 kfree(cpu_clamping_mask);
830
831 cancel_delayed_work_sync(&poll_pkg_cstate_work);
832 debugfs_remove_recursive(debug_dir);
833}
834module_exit(powerclamp_exit);
835
836MODULE_LICENSE("GPL");
837MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
838MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
839MODULE_DESCRIPTION("Package Level C-state Idle Injection for Intel CPUs");