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1/*
2 * drivers/cpufreq/cpufreq_ondemand.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6 * Jun Nakajima <jun.nakajima@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/cpufreq.h>
17#include <linux/cpu.h>
18#include <linux/jiffies.h>
19#include <linux/kernel_stat.h>
20#include <linux/mutex.h>
21#include <linux/hrtimer.h>
22#include <linux/tick.h>
23#include <linux/ktime.h>
24#include <linux/sched.h>
25
26/*
27 * dbs is used in this file as a shortform for demandbased switching
28 * It helps to keep variable names smaller, simpler
29 */
30
31#define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10)
32#define DEF_FREQUENCY_UP_THRESHOLD (80)
33#define DEF_SAMPLING_DOWN_FACTOR (1)
34#define MAX_SAMPLING_DOWN_FACTOR (100000)
35#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3)
36#define MICRO_FREQUENCY_UP_THRESHOLD (95)
37#define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000)
38#define MIN_FREQUENCY_UP_THRESHOLD (11)
39#define MAX_FREQUENCY_UP_THRESHOLD (100)
40
41/*
42 * The polling frequency of this governor depends on the capability of
43 * the processor. Default polling frequency is 1000 times the transition
44 * latency of the processor. The governor will work on any processor with
45 * transition latency <= 10mS, using appropriate sampling
46 * rate.
47 * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
48 * this governor will not work.
49 * All times here are in uS.
50 */
51#define MIN_SAMPLING_RATE_RATIO (2)
52
53static unsigned int min_sampling_rate;
54
55#define LATENCY_MULTIPLIER (1000)
56#define MIN_LATENCY_MULTIPLIER (100)
57#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
58
59static void do_dbs_timer(struct work_struct *work);
60static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
61 unsigned int event);
62
63#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
64static
65#endif
66struct cpufreq_governor cpufreq_gov_ondemand = {
67 .name = "ondemand",
68 .governor = cpufreq_governor_dbs,
69 .max_transition_latency = TRANSITION_LATENCY_LIMIT,
70 .owner = THIS_MODULE,
71};
72
73/* Sampling types */
74enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
75
76struct cpu_dbs_info_s {
77 cputime64_t prev_cpu_idle;
78 cputime64_t prev_cpu_iowait;
79 cputime64_t prev_cpu_wall;
80 cputime64_t prev_cpu_nice;
81 struct cpufreq_policy *cur_policy;
82 struct delayed_work work;
83 struct cpufreq_frequency_table *freq_table;
84 unsigned int freq_lo;
85 unsigned int freq_lo_jiffies;
86 unsigned int freq_hi_jiffies;
87 unsigned int rate_mult;
88 int cpu;
89 unsigned int sample_type:1;
90 /*
91 * percpu mutex that serializes governor limit change with
92 * do_dbs_timer invocation. We do not want do_dbs_timer to run
93 * when user is changing the governor or limits.
94 */
95 struct mutex timer_mutex;
96};
97static DEFINE_PER_CPU(struct cpu_dbs_info_s, od_cpu_dbs_info);
98
99static unsigned int dbs_enable; /* number of CPUs using this policy */
100
101/*
102 * dbs_mutex protects dbs_enable in governor start/stop.
103 */
104static DEFINE_MUTEX(dbs_mutex);
105
106static struct dbs_tuners {
107 unsigned int sampling_rate;
108 unsigned int up_threshold;
109 unsigned int down_differential;
110 unsigned int ignore_nice;
111 unsigned int sampling_down_factor;
112 unsigned int powersave_bias;
113 unsigned int io_is_busy;
114} dbs_tuners_ins = {
115 .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
116 .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
117 .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
118 .ignore_nice = 0,
119 .powersave_bias = 0,
120};
121
122static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
123 cputime64_t *wall)
124{
125 cputime64_t idle_time;
126 cputime64_t cur_wall_time;
127 cputime64_t busy_time;
128
129 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
130 busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
131 kstat_cpu(cpu).cpustat.system);
132
133 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);
134 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);
135 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);
136 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);
137
138 idle_time = cputime64_sub(cur_wall_time, busy_time);
139 if (wall)
140 *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time);
141
142 return (cputime64_t)jiffies_to_usecs(idle_time);
143}
144
145static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
146{
147 u64 idle_time = get_cpu_idle_time_us(cpu, wall);
148
149 if (idle_time == -1ULL)
150 return get_cpu_idle_time_jiffy(cpu, wall);
151
152 return idle_time;
153}
154
155static inline cputime64_t get_cpu_iowait_time(unsigned int cpu, cputime64_t *wall)
156{
157 u64 iowait_time = get_cpu_iowait_time_us(cpu, wall);
158
159 if (iowait_time == -1ULL)
160 return 0;
161
162 return iowait_time;
163}
164
165/*
166 * Find right freq to be set now with powersave_bias on.
167 * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
168 * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
169 */
170static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
171 unsigned int freq_next,
172 unsigned int relation)
173{
174 unsigned int freq_req, freq_reduc, freq_avg;
175 unsigned int freq_hi, freq_lo;
176 unsigned int index = 0;
177 unsigned int jiffies_total, jiffies_hi, jiffies_lo;
178 struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
179 policy->cpu);
180
181 if (!dbs_info->freq_table) {
182 dbs_info->freq_lo = 0;
183 dbs_info->freq_lo_jiffies = 0;
184 return freq_next;
185 }
186
187 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
188 relation, &index);
189 freq_req = dbs_info->freq_table[index].frequency;
190 freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000;
191 freq_avg = freq_req - freq_reduc;
192
193 /* Find freq bounds for freq_avg in freq_table */
194 index = 0;
195 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
196 CPUFREQ_RELATION_H, &index);
197 freq_lo = dbs_info->freq_table[index].frequency;
198 index = 0;
199 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
200 CPUFREQ_RELATION_L, &index);
201 freq_hi = dbs_info->freq_table[index].frequency;
202
203 /* Find out how long we have to be in hi and lo freqs */
204 if (freq_hi == freq_lo) {
205 dbs_info->freq_lo = 0;
206 dbs_info->freq_lo_jiffies = 0;
207 return freq_lo;
208 }
209 jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
210 jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
211 jiffies_hi += ((freq_hi - freq_lo) / 2);
212 jiffies_hi /= (freq_hi - freq_lo);
213 jiffies_lo = jiffies_total - jiffies_hi;
214 dbs_info->freq_lo = freq_lo;
215 dbs_info->freq_lo_jiffies = jiffies_lo;
216 dbs_info->freq_hi_jiffies = jiffies_hi;
217 return freq_hi;
218}
219
220static void ondemand_powersave_bias_init_cpu(int cpu)
221{
222 struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
223 dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
224 dbs_info->freq_lo = 0;
225}
226
227static void ondemand_powersave_bias_init(void)
228{
229 int i;
230 for_each_online_cpu(i) {
231 ondemand_powersave_bias_init_cpu(i);
232 }
233}
234
235/************************** sysfs interface ************************/
236
237static ssize_t show_sampling_rate_min(struct kobject *kobj,
238 struct attribute *attr, char *buf)
239{
240 return sprintf(buf, "%u\n", min_sampling_rate);
241}
242
243define_one_global_ro(sampling_rate_min);
244
245/* cpufreq_ondemand Governor Tunables */
246#define show_one(file_name, object) \
247static ssize_t show_##file_name \
248(struct kobject *kobj, struct attribute *attr, char *buf) \
249{ \
250 return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
251}
252show_one(sampling_rate, sampling_rate);
253show_one(io_is_busy, io_is_busy);
254show_one(up_threshold, up_threshold);
255show_one(sampling_down_factor, sampling_down_factor);
256show_one(ignore_nice_load, ignore_nice);
257show_one(powersave_bias, powersave_bias);
258
259static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
260 const char *buf, size_t count)
261{
262 unsigned int input;
263 int ret;
264 ret = sscanf(buf, "%u", &input);
265 if (ret != 1)
266 return -EINVAL;
267 dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
268 return count;
269}
270
271static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b,
272 const char *buf, size_t count)
273{
274 unsigned int input;
275 int ret;
276
277 ret = sscanf(buf, "%u", &input);
278 if (ret != 1)
279 return -EINVAL;
280 dbs_tuners_ins.io_is_busy = !!input;
281 return count;
282}
283
284static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
285 const char *buf, size_t count)
286{
287 unsigned int input;
288 int ret;
289 ret = sscanf(buf, "%u", &input);
290
291 if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
292 input < MIN_FREQUENCY_UP_THRESHOLD) {
293 return -EINVAL;
294 }
295 dbs_tuners_ins.up_threshold = input;
296 return count;
297}
298
299static ssize_t store_sampling_down_factor(struct kobject *a,
300 struct attribute *b, const char *buf, size_t count)
301{
302 unsigned int input, j;
303 int ret;
304 ret = sscanf(buf, "%u", &input);
305
306 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
307 return -EINVAL;
308 dbs_tuners_ins.sampling_down_factor = input;
309
310 /* Reset down sampling multiplier in case it was active */
311 for_each_online_cpu(j) {
312 struct cpu_dbs_info_s *dbs_info;
313 dbs_info = &per_cpu(od_cpu_dbs_info, j);
314 dbs_info->rate_mult = 1;
315 }
316 return count;
317}
318
319static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
320 const char *buf, size_t count)
321{
322 unsigned int input;
323 int ret;
324
325 unsigned int j;
326
327 ret = sscanf(buf, "%u", &input);
328 if (ret != 1)
329 return -EINVAL;
330
331 if (input > 1)
332 input = 1;
333
334 if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
335 return count;
336 }
337 dbs_tuners_ins.ignore_nice = input;
338
339 /* we need to re-evaluate prev_cpu_idle */
340 for_each_online_cpu(j) {
341 struct cpu_dbs_info_s *dbs_info;
342 dbs_info = &per_cpu(od_cpu_dbs_info, j);
343 dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
344 &dbs_info->prev_cpu_wall);
345 if (dbs_tuners_ins.ignore_nice)
346 dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
347
348 }
349 return count;
350}
351
352static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b,
353 const char *buf, size_t count)
354{
355 unsigned int input;
356 int ret;
357 ret = sscanf(buf, "%u", &input);
358
359 if (ret != 1)
360 return -EINVAL;
361
362 if (input > 1000)
363 input = 1000;
364
365 dbs_tuners_ins.powersave_bias = input;
366 ondemand_powersave_bias_init();
367 return count;
368}
369
370define_one_global_rw(sampling_rate);
371define_one_global_rw(io_is_busy);
372define_one_global_rw(up_threshold);
373define_one_global_rw(sampling_down_factor);
374define_one_global_rw(ignore_nice_load);
375define_one_global_rw(powersave_bias);
376
377static struct attribute *dbs_attributes[] = {
378 &sampling_rate_min.attr,
379 &sampling_rate.attr,
380 &up_threshold.attr,
381 &sampling_down_factor.attr,
382 &ignore_nice_load.attr,
383 &powersave_bias.attr,
384 &io_is_busy.attr,
385 NULL
386};
387
388static struct attribute_group dbs_attr_group = {
389 .attrs = dbs_attributes,
390 .name = "ondemand",
391};
392
393/************************** sysfs end ************************/
394
395static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq)
396{
397 if (dbs_tuners_ins.powersave_bias)
398 freq = powersave_bias_target(p, freq, CPUFREQ_RELATION_H);
399 else if (p->cur == p->max)
400 return;
401
402 __cpufreq_driver_target(p, freq, dbs_tuners_ins.powersave_bias ?
403 CPUFREQ_RELATION_L : CPUFREQ_RELATION_H);
404}
405
406static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
407{
408 unsigned int max_load_freq;
409
410 struct cpufreq_policy *policy;
411 unsigned int j;
412
413 this_dbs_info->freq_lo = 0;
414 policy = this_dbs_info->cur_policy;
415
416 /*
417 * Every sampling_rate, we check, if current idle time is less
418 * than 20% (default), then we try to increase frequency
419 * Every sampling_rate, we look for a the lowest
420 * frequency which can sustain the load while keeping idle time over
421 * 30%. If such a frequency exist, we try to decrease to this frequency.
422 *
423 * Any frequency increase takes it to the maximum frequency.
424 * Frequency reduction happens at minimum steps of
425 * 5% (default) of current frequency
426 */
427
428 /* Get Absolute Load - in terms of freq */
429 max_load_freq = 0;
430
431 for_each_cpu(j, policy->cpus) {
432 struct cpu_dbs_info_s *j_dbs_info;
433 cputime64_t cur_wall_time, cur_idle_time, cur_iowait_time;
434 unsigned int idle_time, wall_time, iowait_time;
435 unsigned int load, load_freq;
436 int freq_avg;
437
438 j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
439
440 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
441 cur_iowait_time = get_cpu_iowait_time(j, &cur_wall_time);
442
443 wall_time = (unsigned int) cputime64_sub(cur_wall_time,
444 j_dbs_info->prev_cpu_wall);
445 j_dbs_info->prev_cpu_wall = cur_wall_time;
446
447 idle_time = (unsigned int) cputime64_sub(cur_idle_time,
448 j_dbs_info->prev_cpu_idle);
449 j_dbs_info->prev_cpu_idle = cur_idle_time;
450
451 iowait_time = (unsigned int) cputime64_sub(cur_iowait_time,
452 j_dbs_info->prev_cpu_iowait);
453 j_dbs_info->prev_cpu_iowait = cur_iowait_time;
454
455 if (dbs_tuners_ins.ignore_nice) {
456 cputime64_t cur_nice;
457 unsigned long cur_nice_jiffies;
458
459 cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,
460 j_dbs_info->prev_cpu_nice);
461 /*
462 * Assumption: nice time between sampling periods will
463 * be less than 2^32 jiffies for 32 bit sys
464 */
465 cur_nice_jiffies = (unsigned long)
466 cputime64_to_jiffies64(cur_nice);
467
468 j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
469 idle_time += jiffies_to_usecs(cur_nice_jiffies);
470 }
471
472 /*
473 * For the purpose of ondemand, waiting for disk IO is an
474 * indication that you're performance critical, and not that
475 * the system is actually idle. So subtract the iowait time
476 * from the cpu idle time.
477 */
478
479 if (dbs_tuners_ins.io_is_busy && idle_time >= iowait_time)
480 idle_time -= iowait_time;
481
482 if (unlikely(!wall_time || wall_time < idle_time))
483 continue;
484
485 load = 100 * (wall_time - idle_time) / wall_time;
486
487 freq_avg = __cpufreq_driver_getavg(policy, j);
488 if (freq_avg <= 0)
489 freq_avg = policy->cur;
490
491 load_freq = load * freq_avg;
492 if (load_freq > max_load_freq)
493 max_load_freq = load_freq;
494 }
495
496 /* Check for frequency increase */
497 if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) {
498 /* If switching to max speed, apply sampling_down_factor */
499 if (policy->cur < policy->max)
500 this_dbs_info->rate_mult =
501 dbs_tuners_ins.sampling_down_factor;
502 dbs_freq_increase(policy, policy->max);
503 return;
504 }
505
506 /* Check for frequency decrease */
507 /* if we cannot reduce the frequency anymore, break out early */
508 if (policy->cur == policy->min)
509 return;
510
511 /*
512 * The optimal frequency is the frequency that is the lowest that
513 * can support the current CPU usage without triggering the up
514 * policy. To be safe, we focus 10 points under the threshold.
515 */
516 if (max_load_freq <
517 (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) *
518 policy->cur) {
519 unsigned int freq_next;
520 freq_next = max_load_freq /
521 (dbs_tuners_ins.up_threshold -
522 dbs_tuners_ins.down_differential);
523
524 /* No longer fully busy, reset rate_mult */
525 this_dbs_info->rate_mult = 1;
526
527 if (freq_next < policy->min)
528 freq_next = policy->min;
529
530 if (!dbs_tuners_ins.powersave_bias) {
531 __cpufreq_driver_target(policy, freq_next,
532 CPUFREQ_RELATION_L);
533 } else {
534 int freq = powersave_bias_target(policy, freq_next,
535 CPUFREQ_RELATION_L);
536 __cpufreq_driver_target(policy, freq,
537 CPUFREQ_RELATION_L);
538 }
539 }
540}
541
542static void do_dbs_timer(struct work_struct *work)
543{
544 struct cpu_dbs_info_s *dbs_info =
545 container_of(work, struct cpu_dbs_info_s, work.work);
546 unsigned int cpu = dbs_info->cpu;
547 int sample_type = dbs_info->sample_type;
548
549 int delay;
550
551 mutex_lock(&dbs_info->timer_mutex);
552
553 /* Common NORMAL_SAMPLE setup */
554 dbs_info->sample_type = DBS_NORMAL_SAMPLE;
555 if (!dbs_tuners_ins.powersave_bias ||
556 sample_type == DBS_NORMAL_SAMPLE) {
557 dbs_check_cpu(dbs_info);
558 if (dbs_info->freq_lo) {
559 /* Setup timer for SUB_SAMPLE */
560 dbs_info->sample_type = DBS_SUB_SAMPLE;
561 delay = dbs_info->freq_hi_jiffies;
562 } else {
563 /* We want all CPUs to do sampling nearly on
564 * same jiffy
565 */
566 delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate
567 * dbs_info->rate_mult);
568
569 if (num_online_cpus() > 1)
570 delay -= jiffies % delay;
571 }
572 } else {
573 __cpufreq_driver_target(dbs_info->cur_policy,
574 dbs_info->freq_lo, CPUFREQ_RELATION_H);
575 delay = dbs_info->freq_lo_jiffies;
576 }
577 schedule_delayed_work_on(cpu, &dbs_info->work, delay);
578 mutex_unlock(&dbs_info->timer_mutex);
579}
580
581static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
582{
583 /* We want all CPUs to do sampling nearly on same jiffy */
584 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
585
586 if (num_online_cpus() > 1)
587 delay -= jiffies % delay;
588
589 dbs_info->sample_type = DBS_NORMAL_SAMPLE;
590 INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
591 schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay);
592}
593
594static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
595{
596 cancel_delayed_work_sync(&dbs_info->work);
597}
598
599/*
600 * Not all CPUs want IO time to be accounted as busy; this dependson how
601 * efficient idling at a higher frequency/voltage is.
602 * Pavel Machek says this is not so for various generations of AMD and old
603 * Intel systems.
604 * Mike Chan (androidlcom) calis this is also not true for ARM.
605 * Because of this, whitelist specific known (series) of CPUs by default, and
606 * leave all others up to the user.
607 */
608static int should_io_be_busy(void)
609{
610#if defined(CONFIG_X86)
611 /*
612 * For Intel, Core 2 (model 15) andl later have an efficient idle.
613 */
614 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
615 boot_cpu_data.x86 == 6 &&
616 boot_cpu_data.x86_model >= 15)
617 return 1;
618#endif
619 return 0;
620}
621
622static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
623 unsigned int event)
624{
625 unsigned int cpu = policy->cpu;
626 struct cpu_dbs_info_s *this_dbs_info;
627 unsigned int j;
628 int rc;
629
630 this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
631
632 switch (event) {
633 case CPUFREQ_GOV_START:
634 if ((!cpu_online(cpu)) || (!policy->cur))
635 return -EINVAL;
636
637 mutex_lock(&dbs_mutex);
638
639 dbs_enable++;
640 for_each_cpu(j, policy->cpus) {
641 struct cpu_dbs_info_s *j_dbs_info;
642 j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
643 j_dbs_info->cur_policy = policy;
644
645 j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
646 &j_dbs_info->prev_cpu_wall);
647 if (dbs_tuners_ins.ignore_nice) {
648 j_dbs_info->prev_cpu_nice =
649 kstat_cpu(j).cpustat.nice;
650 }
651 }
652 this_dbs_info->cpu = cpu;
653 this_dbs_info->rate_mult = 1;
654 ondemand_powersave_bias_init_cpu(cpu);
655 /*
656 * Start the timerschedule work, when this governor
657 * is used for first time
658 */
659 if (dbs_enable == 1) {
660 unsigned int latency;
661
662 rc = sysfs_create_group(cpufreq_global_kobject,
663 &dbs_attr_group);
664 if (rc) {
665 mutex_unlock(&dbs_mutex);
666 return rc;
667 }
668
669 /* policy latency is in nS. Convert it to uS first */
670 latency = policy->cpuinfo.transition_latency / 1000;
671 if (latency == 0)
672 latency = 1;
673 /* Bring kernel and HW constraints together */
674 min_sampling_rate = max(min_sampling_rate,
675 MIN_LATENCY_MULTIPLIER * latency);
676 dbs_tuners_ins.sampling_rate =
677 max(min_sampling_rate,
678 latency * LATENCY_MULTIPLIER);
679 dbs_tuners_ins.io_is_busy = should_io_be_busy();
680 }
681 mutex_unlock(&dbs_mutex);
682
683 mutex_init(&this_dbs_info->timer_mutex);
684 dbs_timer_init(this_dbs_info);
685 break;
686
687 case CPUFREQ_GOV_STOP:
688 dbs_timer_exit(this_dbs_info);
689
690 mutex_lock(&dbs_mutex);
691 mutex_destroy(&this_dbs_info->timer_mutex);
692 dbs_enable--;
693 mutex_unlock(&dbs_mutex);
694 if (!dbs_enable)
695 sysfs_remove_group(cpufreq_global_kobject,
696 &dbs_attr_group);
697
698 break;
699
700 case CPUFREQ_GOV_LIMITS:
701 mutex_lock(&this_dbs_info->timer_mutex);
702 if (policy->max < this_dbs_info->cur_policy->cur)
703 __cpufreq_driver_target(this_dbs_info->cur_policy,
704 policy->max, CPUFREQ_RELATION_H);
705 else if (policy->min > this_dbs_info->cur_policy->cur)
706 __cpufreq_driver_target(this_dbs_info->cur_policy,
707 policy->min, CPUFREQ_RELATION_L);
708 mutex_unlock(&this_dbs_info->timer_mutex);
709 break;
710 }
711 return 0;
712}
713
714static int __init cpufreq_gov_dbs_init(void)
715{
716 cputime64_t wall;
717 u64 idle_time;
718 int cpu = get_cpu();
719
720 idle_time = get_cpu_idle_time_us(cpu, &wall);
721 put_cpu();
722 if (idle_time != -1ULL) {
723 /* Idle micro accounting is supported. Use finer thresholds */
724 dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
725 dbs_tuners_ins.down_differential =
726 MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
727 /*
728 * In no_hz/micro accounting case we set the minimum frequency
729 * not depending on HZ, but fixed (very low). The deferred
730 * timer might skip some samples if idle/sleeping as needed.
731 */
732 min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
733 } else {
734 /* For correct statistics, we need 10 ticks for each measure */
735 min_sampling_rate =
736 MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10);
737 }
738
739 return cpufreq_register_governor(&cpufreq_gov_ondemand);
740}
741
742static void __exit cpufreq_gov_dbs_exit(void)
743{
744 cpufreq_unregister_governor(&cpufreq_gov_ondemand);
745}
746
747
748MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
749MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
750MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
751 "Low Latency Frequency Transition capable processors");
752MODULE_LICENSE("GPL");
753
754#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
755fs_initcall(cpufreq_gov_dbs_init);
756#else
757module_init(cpufreq_gov_dbs_init);
758#endif
759module_exit(cpufreq_gov_dbs_exit);
1/*
2 * drivers/cpufreq/cpufreq_ondemand.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6 * Jun Nakajima <jun.nakajima@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/cpu.h>
16#include <linux/percpu-defs.h>
17#include <linux/slab.h>
18#include <linux/tick.h>
19#include "cpufreq_governor.h"
20
21/* On-demand governor macros */
22#define DEF_FREQUENCY_UP_THRESHOLD (80)
23#define DEF_SAMPLING_DOWN_FACTOR (1)
24#define MAX_SAMPLING_DOWN_FACTOR (100000)
25#define MICRO_FREQUENCY_UP_THRESHOLD (95)
26#define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000)
27#define MIN_FREQUENCY_UP_THRESHOLD (11)
28#define MAX_FREQUENCY_UP_THRESHOLD (100)
29
30static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info);
31
32static struct od_ops od_ops;
33
34#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
35static struct cpufreq_governor cpufreq_gov_ondemand;
36#endif
37
38static unsigned int default_powersave_bias;
39
40static void ondemand_powersave_bias_init_cpu(int cpu)
41{
42 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
43
44 dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
45 dbs_info->freq_lo = 0;
46}
47
48/*
49 * Not all CPUs want IO time to be accounted as busy; this depends on how
50 * efficient idling at a higher frequency/voltage is.
51 * Pavel Machek says this is not so for various generations of AMD and old
52 * Intel systems.
53 * Mike Chan (android.com) claims this is also not true for ARM.
54 * Because of this, whitelist specific known (series) of CPUs by default, and
55 * leave all others up to the user.
56 */
57static int should_io_be_busy(void)
58{
59#if defined(CONFIG_X86)
60 /*
61 * For Intel, Core 2 (model 15) and later have an efficient idle.
62 */
63 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
64 boot_cpu_data.x86 == 6 &&
65 boot_cpu_data.x86_model >= 15)
66 return 1;
67#endif
68 return 0;
69}
70
71/*
72 * Find right freq to be set now with powersave_bias on.
73 * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
74 * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
75 */
76static unsigned int generic_powersave_bias_target(struct cpufreq_policy *policy,
77 unsigned int freq_next, unsigned int relation)
78{
79 unsigned int freq_req, freq_reduc, freq_avg;
80 unsigned int freq_hi, freq_lo;
81 unsigned int index = 0;
82 unsigned int jiffies_total, jiffies_hi, jiffies_lo;
83 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
84 policy->cpu);
85 struct dbs_data *dbs_data = policy->governor_data;
86 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
87
88 if (!dbs_info->freq_table) {
89 dbs_info->freq_lo = 0;
90 dbs_info->freq_lo_jiffies = 0;
91 return freq_next;
92 }
93
94 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
95 relation, &index);
96 freq_req = dbs_info->freq_table[index].frequency;
97 freq_reduc = freq_req * od_tuners->powersave_bias / 1000;
98 freq_avg = freq_req - freq_reduc;
99
100 /* Find freq bounds for freq_avg in freq_table */
101 index = 0;
102 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
103 CPUFREQ_RELATION_H, &index);
104 freq_lo = dbs_info->freq_table[index].frequency;
105 index = 0;
106 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
107 CPUFREQ_RELATION_L, &index);
108 freq_hi = dbs_info->freq_table[index].frequency;
109
110 /* Find out how long we have to be in hi and lo freqs */
111 if (freq_hi == freq_lo) {
112 dbs_info->freq_lo = 0;
113 dbs_info->freq_lo_jiffies = 0;
114 return freq_lo;
115 }
116 jiffies_total = usecs_to_jiffies(od_tuners->sampling_rate);
117 jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
118 jiffies_hi += ((freq_hi - freq_lo) / 2);
119 jiffies_hi /= (freq_hi - freq_lo);
120 jiffies_lo = jiffies_total - jiffies_hi;
121 dbs_info->freq_lo = freq_lo;
122 dbs_info->freq_lo_jiffies = jiffies_lo;
123 dbs_info->freq_hi_jiffies = jiffies_hi;
124 return freq_hi;
125}
126
127static void ondemand_powersave_bias_init(void)
128{
129 int i;
130 for_each_online_cpu(i) {
131 ondemand_powersave_bias_init_cpu(i);
132 }
133}
134
135static void dbs_freq_increase(struct cpufreq_policy *policy, unsigned int freq)
136{
137 struct dbs_data *dbs_data = policy->governor_data;
138 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
139
140 if (od_tuners->powersave_bias)
141 freq = od_ops.powersave_bias_target(policy, freq,
142 CPUFREQ_RELATION_H);
143 else if (policy->cur == policy->max)
144 return;
145
146 __cpufreq_driver_target(policy, freq, od_tuners->powersave_bias ?
147 CPUFREQ_RELATION_L : CPUFREQ_RELATION_H);
148}
149
150/*
151 * Every sampling_rate, we check, if current idle time is less than 20%
152 * (default), then we try to increase frequency. Else, we adjust the frequency
153 * proportional to load.
154 */
155static void od_check_cpu(int cpu, unsigned int load)
156{
157 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
158 struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
159 struct dbs_data *dbs_data = policy->governor_data;
160 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
161
162 dbs_info->freq_lo = 0;
163
164 /* Check for frequency increase */
165 if (load > od_tuners->up_threshold) {
166 /* If switching to max speed, apply sampling_down_factor */
167 if (policy->cur < policy->max)
168 dbs_info->rate_mult =
169 od_tuners->sampling_down_factor;
170 dbs_freq_increase(policy, policy->max);
171 } else {
172 /* Calculate the next frequency proportional to load */
173 unsigned int freq_next;
174 freq_next = load * policy->cpuinfo.max_freq / 100;
175
176 /* No longer fully busy, reset rate_mult */
177 dbs_info->rate_mult = 1;
178
179 if (!od_tuners->powersave_bias) {
180 __cpufreq_driver_target(policy, freq_next,
181 CPUFREQ_RELATION_L);
182 return;
183 }
184
185 freq_next = od_ops.powersave_bias_target(policy, freq_next,
186 CPUFREQ_RELATION_L);
187 __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
188 }
189}
190
191static void od_dbs_timer(struct work_struct *work)
192{
193 struct od_cpu_dbs_info_s *dbs_info =
194 container_of(work, struct od_cpu_dbs_info_s, cdbs.work.work);
195 unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
196 struct od_cpu_dbs_info_s *core_dbs_info = &per_cpu(od_cpu_dbs_info,
197 cpu);
198 struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data;
199 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
200 int delay = 0, sample_type = core_dbs_info->sample_type;
201 bool modify_all = true;
202
203 mutex_lock(&core_dbs_info->cdbs.timer_mutex);
204 if (!need_load_eval(&core_dbs_info->cdbs, od_tuners->sampling_rate)) {
205 modify_all = false;
206 goto max_delay;
207 }
208
209 /* Common NORMAL_SAMPLE setup */
210 core_dbs_info->sample_type = OD_NORMAL_SAMPLE;
211 if (sample_type == OD_SUB_SAMPLE) {
212 delay = core_dbs_info->freq_lo_jiffies;
213 __cpufreq_driver_target(core_dbs_info->cdbs.cur_policy,
214 core_dbs_info->freq_lo, CPUFREQ_RELATION_H);
215 } else {
216 dbs_check_cpu(dbs_data, cpu);
217 if (core_dbs_info->freq_lo) {
218 /* Setup timer for SUB_SAMPLE */
219 core_dbs_info->sample_type = OD_SUB_SAMPLE;
220 delay = core_dbs_info->freq_hi_jiffies;
221 }
222 }
223
224max_delay:
225 if (!delay)
226 delay = delay_for_sampling_rate(od_tuners->sampling_rate
227 * core_dbs_info->rate_mult);
228
229 gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all);
230 mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
231}
232
233/************************** sysfs interface ************************/
234static struct common_dbs_data od_dbs_cdata;
235
236/**
237 * update_sampling_rate - update sampling rate effective immediately if needed.
238 * @new_rate: new sampling rate
239 *
240 * If new rate is smaller than the old, simply updating
241 * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the
242 * original sampling_rate was 1 second and the requested new sampling rate is 10
243 * ms because the user needs immediate reaction from ondemand governor, but not
244 * sure if higher frequency will be required or not, then, the governor may
245 * change the sampling rate too late; up to 1 second later. Thus, if we are
246 * reducing the sampling rate, we need to make the new value effective
247 * immediately.
248 */
249static void update_sampling_rate(struct dbs_data *dbs_data,
250 unsigned int new_rate)
251{
252 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
253 int cpu;
254
255 od_tuners->sampling_rate = new_rate = max(new_rate,
256 dbs_data->min_sampling_rate);
257
258 for_each_online_cpu(cpu) {
259 struct cpufreq_policy *policy;
260 struct od_cpu_dbs_info_s *dbs_info;
261 unsigned long next_sampling, appointed_at;
262
263 policy = cpufreq_cpu_get(cpu);
264 if (!policy)
265 continue;
266 if (policy->governor != &cpufreq_gov_ondemand) {
267 cpufreq_cpu_put(policy);
268 continue;
269 }
270 dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
271 cpufreq_cpu_put(policy);
272
273 mutex_lock(&dbs_info->cdbs.timer_mutex);
274
275 if (!delayed_work_pending(&dbs_info->cdbs.work)) {
276 mutex_unlock(&dbs_info->cdbs.timer_mutex);
277 continue;
278 }
279
280 next_sampling = jiffies + usecs_to_jiffies(new_rate);
281 appointed_at = dbs_info->cdbs.work.timer.expires;
282
283 if (time_before(next_sampling, appointed_at)) {
284
285 mutex_unlock(&dbs_info->cdbs.timer_mutex);
286 cancel_delayed_work_sync(&dbs_info->cdbs.work);
287 mutex_lock(&dbs_info->cdbs.timer_mutex);
288
289 gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy,
290 usecs_to_jiffies(new_rate), true);
291
292 }
293 mutex_unlock(&dbs_info->cdbs.timer_mutex);
294 }
295}
296
297static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
298 size_t count)
299{
300 unsigned int input;
301 int ret;
302 ret = sscanf(buf, "%u", &input);
303 if (ret != 1)
304 return -EINVAL;
305
306 update_sampling_rate(dbs_data, input);
307 return count;
308}
309
310static ssize_t store_io_is_busy(struct dbs_data *dbs_data, const char *buf,
311 size_t count)
312{
313 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
314 unsigned int input;
315 int ret;
316 unsigned int j;
317
318 ret = sscanf(buf, "%u", &input);
319 if (ret != 1)
320 return -EINVAL;
321 od_tuners->io_is_busy = !!input;
322
323 /* we need to re-evaluate prev_cpu_idle */
324 for_each_online_cpu(j) {
325 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
326 j);
327 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
328 &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
329 }
330 return count;
331}
332
333static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
334 size_t count)
335{
336 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
337 unsigned int input;
338 int ret;
339 ret = sscanf(buf, "%u", &input);
340
341 if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
342 input < MIN_FREQUENCY_UP_THRESHOLD) {
343 return -EINVAL;
344 }
345
346 od_tuners->up_threshold = input;
347 return count;
348}
349
350static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
351 const char *buf, size_t count)
352{
353 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
354 unsigned int input, j;
355 int ret;
356 ret = sscanf(buf, "%u", &input);
357
358 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
359 return -EINVAL;
360 od_tuners->sampling_down_factor = input;
361
362 /* Reset down sampling multiplier in case it was active */
363 for_each_online_cpu(j) {
364 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
365 j);
366 dbs_info->rate_mult = 1;
367 }
368 return count;
369}
370
371static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
372 const char *buf, size_t count)
373{
374 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
375 unsigned int input;
376 int ret;
377
378 unsigned int j;
379
380 ret = sscanf(buf, "%u", &input);
381 if (ret != 1)
382 return -EINVAL;
383
384 if (input > 1)
385 input = 1;
386
387 if (input == od_tuners->ignore_nice_load) { /* nothing to do */
388 return count;
389 }
390 od_tuners->ignore_nice_load = input;
391
392 /* we need to re-evaluate prev_cpu_idle */
393 for_each_online_cpu(j) {
394 struct od_cpu_dbs_info_s *dbs_info;
395 dbs_info = &per_cpu(od_cpu_dbs_info, j);
396 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
397 &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
398 if (od_tuners->ignore_nice_load)
399 dbs_info->cdbs.prev_cpu_nice =
400 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
401
402 }
403 return count;
404}
405
406static ssize_t store_powersave_bias(struct dbs_data *dbs_data, const char *buf,
407 size_t count)
408{
409 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
410 unsigned int input;
411 int ret;
412 ret = sscanf(buf, "%u", &input);
413
414 if (ret != 1)
415 return -EINVAL;
416
417 if (input > 1000)
418 input = 1000;
419
420 od_tuners->powersave_bias = input;
421 ondemand_powersave_bias_init();
422 return count;
423}
424
425show_store_one(od, sampling_rate);
426show_store_one(od, io_is_busy);
427show_store_one(od, up_threshold);
428show_store_one(od, sampling_down_factor);
429show_store_one(od, ignore_nice_load);
430show_store_one(od, powersave_bias);
431declare_show_sampling_rate_min(od);
432
433gov_sys_pol_attr_rw(sampling_rate);
434gov_sys_pol_attr_rw(io_is_busy);
435gov_sys_pol_attr_rw(up_threshold);
436gov_sys_pol_attr_rw(sampling_down_factor);
437gov_sys_pol_attr_rw(ignore_nice_load);
438gov_sys_pol_attr_rw(powersave_bias);
439gov_sys_pol_attr_ro(sampling_rate_min);
440
441static struct attribute *dbs_attributes_gov_sys[] = {
442 &sampling_rate_min_gov_sys.attr,
443 &sampling_rate_gov_sys.attr,
444 &up_threshold_gov_sys.attr,
445 &sampling_down_factor_gov_sys.attr,
446 &ignore_nice_load_gov_sys.attr,
447 &powersave_bias_gov_sys.attr,
448 &io_is_busy_gov_sys.attr,
449 NULL
450};
451
452static struct attribute_group od_attr_group_gov_sys = {
453 .attrs = dbs_attributes_gov_sys,
454 .name = "ondemand",
455};
456
457static struct attribute *dbs_attributes_gov_pol[] = {
458 &sampling_rate_min_gov_pol.attr,
459 &sampling_rate_gov_pol.attr,
460 &up_threshold_gov_pol.attr,
461 &sampling_down_factor_gov_pol.attr,
462 &ignore_nice_load_gov_pol.attr,
463 &powersave_bias_gov_pol.attr,
464 &io_is_busy_gov_pol.attr,
465 NULL
466};
467
468static struct attribute_group od_attr_group_gov_pol = {
469 .attrs = dbs_attributes_gov_pol,
470 .name = "ondemand",
471};
472
473/************************** sysfs end ************************/
474
475static int od_init(struct dbs_data *dbs_data)
476{
477 struct od_dbs_tuners *tuners;
478 u64 idle_time;
479 int cpu;
480
481 tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
482 if (!tuners) {
483 pr_err("%s: kzalloc failed\n", __func__);
484 return -ENOMEM;
485 }
486
487 cpu = get_cpu();
488 idle_time = get_cpu_idle_time_us(cpu, NULL);
489 put_cpu();
490 if (idle_time != -1ULL) {
491 /* Idle micro accounting is supported. Use finer thresholds */
492 tuners->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
493 /*
494 * In nohz/micro accounting case we set the minimum frequency
495 * not depending on HZ, but fixed (very low). The deferred
496 * timer might skip some samples if idle/sleeping as needed.
497 */
498 dbs_data->min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
499 } else {
500 tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
501
502 /* For correct statistics, we need 10 ticks for each measure */
503 dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
504 jiffies_to_usecs(10);
505 }
506
507 tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
508 tuners->ignore_nice_load = 0;
509 tuners->powersave_bias = default_powersave_bias;
510 tuners->io_is_busy = should_io_be_busy();
511
512 dbs_data->tuners = tuners;
513 mutex_init(&dbs_data->mutex);
514 return 0;
515}
516
517static void od_exit(struct dbs_data *dbs_data)
518{
519 kfree(dbs_data->tuners);
520}
521
522define_get_cpu_dbs_routines(od_cpu_dbs_info);
523
524static struct od_ops od_ops = {
525 .powersave_bias_init_cpu = ondemand_powersave_bias_init_cpu,
526 .powersave_bias_target = generic_powersave_bias_target,
527 .freq_increase = dbs_freq_increase,
528};
529
530static struct common_dbs_data od_dbs_cdata = {
531 .governor = GOV_ONDEMAND,
532 .attr_group_gov_sys = &od_attr_group_gov_sys,
533 .attr_group_gov_pol = &od_attr_group_gov_pol,
534 .get_cpu_cdbs = get_cpu_cdbs,
535 .get_cpu_dbs_info_s = get_cpu_dbs_info_s,
536 .gov_dbs_timer = od_dbs_timer,
537 .gov_check_cpu = od_check_cpu,
538 .gov_ops = &od_ops,
539 .init = od_init,
540 .exit = od_exit,
541};
542
543static void od_set_powersave_bias(unsigned int powersave_bias)
544{
545 struct cpufreq_policy *policy;
546 struct dbs_data *dbs_data;
547 struct od_dbs_tuners *od_tuners;
548 unsigned int cpu;
549 cpumask_t done;
550
551 default_powersave_bias = powersave_bias;
552 cpumask_clear(&done);
553
554 get_online_cpus();
555 for_each_online_cpu(cpu) {
556 if (cpumask_test_cpu(cpu, &done))
557 continue;
558
559 policy = per_cpu(od_cpu_dbs_info, cpu).cdbs.cur_policy;
560 if (!policy)
561 continue;
562
563 cpumask_or(&done, &done, policy->cpus);
564
565 if (policy->governor != &cpufreq_gov_ondemand)
566 continue;
567
568 dbs_data = policy->governor_data;
569 od_tuners = dbs_data->tuners;
570 od_tuners->powersave_bias = default_powersave_bias;
571 }
572 put_online_cpus();
573}
574
575void od_register_powersave_bias_handler(unsigned int (*f)
576 (struct cpufreq_policy *, unsigned int, unsigned int),
577 unsigned int powersave_bias)
578{
579 od_ops.powersave_bias_target = f;
580 od_set_powersave_bias(powersave_bias);
581}
582EXPORT_SYMBOL_GPL(od_register_powersave_bias_handler);
583
584void od_unregister_powersave_bias_handler(void)
585{
586 od_ops.powersave_bias_target = generic_powersave_bias_target;
587 od_set_powersave_bias(0);
588}
589EXPORT_SYMBOL_GPL(od_unregister_powersave_bias_handler);
590
591static int od_cpufreq_governor_dbs(struct cpufreq_policy *policy,
592 unsigned int event)
593{
594 return cpufreq_governor_dbs(policy, &od_dbs_cdata, event);
595}
596
597#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
598static
599#endif
600struct cpufreq_governor cpufreq_gov_ondemand = {
601 .name = "ondemand",
602 .governor = od_cpufreq_governor_dbs,
603 .max_transition_latency = TRANSITION_LATENCY_LIMIT,
604 .owner = THIS_MODULE,
605};
606
607static int __init cpufreq_gov_dbs_init(void)
608{
609 return cpufreq_register_governor(&cpufreq_gov_ondemand);
610}
611
612static void __exit cpufreq_gov_dbs_exit(void)
613{
614 cpufreq_unregister_governor(&cpufreq_gov_ondemand);
615}
616
617MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
618MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
619MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
620 "Low Latency Frequency Transition capable processors");
621MODULE_LICENSE("GPL");
622
623#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
624fs_initcall(cpufreq_gov_dbs_init);
625#else
626module_init(cpufreq_gov_dbs_init);
627#endif
628module_exit(cpufreq_gov_dbs_exit);