2 * intel_pstate.c: Native P state management for Intel processors
4 * (C) Copyright 2012 Intel Corporation
5 * Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; version 2
13 #include <linux/kernel.h>
14 #include <linux/kernel_stat.h>
15 #include <linux/module.h>
16 #include <linux/ktime.h>
17 #include <linux/hrtimer.h>
18 #include <linux/tick.h>
19 #include <linux/slab.h>
20 #include <linux/sched.h>
21 #include <linux/list.h>
22 #include <linux/cpu.h>
23 #include <linux/cpufreq.h>
24 #include <linux/sysfs.h>
25 #include <linux/types.h>
27 #include <linux/debugfs.h>
28 #include <trace/events/power.h>
30 #include <asm/div64.h>
32 #include <asm/cpu_device_id.h>
34 #define SAMPLE_COUNT 3
37 #define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
38 #define fp_toint(X) ((X) >> FRAC_BITS)
40 static inline int32_t mul_fp(int32_t x, int32_t y)
42 return ((int64_t)x * (int64_t)y) >> FRAC_BITS;
45 static inline int32_t div_fp(int32_t x, int32_t y)
47 return div_s64((int64_t)x << FRAC_BITS, (int64_t)y);
79 struct timer_list timer;
81 struct pstate_adjust_policy *pstate_policy;
82 struct pstate_data pstate;
92 struct sample samples[SAMPLE_COUNT];
95 static struct cpudata **all_cpu_data;
96 struct pstate_adjust_policy {
105 static struct pstate_adjust_policy default_policy = {
106 .sample_rate_ms = 10,
124 static struct perf_limits limits = {
127 .max_perf = int_tofp(1),
130 .max_policy_pct = 100,
131 .max_sysfs_pct = 100,
134 static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
135 int deadband, int integral) {
136 pid->setpoint = setpoint;
137 pid->deadband = deadband;
138 pid->integral = int_tofp(integral);
139 pid->last_err = setpoint - busy;
142 static inline void pid_p_gain_set(struct _pid *pid, int percent)
144 pid->p_gain = div_fp(int_tofp(percent), int_tofp(100));
147 static inline void pid_i_gain_set(struct _pid *pid, int percent)
149 pid->i_gain = div_fp(int_tofp(percent), int_tofp(100));
152 static inline void pid_d_gain_set(struct _pid *pid, int percent)
155 pid->d_gain = div_fp(int_tofp(percent), int_tofp(100));
158 static signed int pid_calc(struct _pid *pid, int busy)
160 signed int err, result;
161 int32_t pterm, dterm, fp_error;
162 int32_t integral_limit;
164 err = pid->setpoint - busy;
165 fp_error = int_tofp(err);
167 if (abs(err) <= pid->deadband)
170 pterm = mul_fp(pid->p_gain, fp_error);
172 pid->integral += fp_error;
174 /* limit the integral term */
175 integral_limit = int_tofp(30);
176 if (pid->integral > integral_limit)
177 pid->integral = integral_limit;
178 if (pid->integral < -integral_limit)
179 pid->integral = -integral_limit;
181 dterm = mul_fp(pid->d_gain, (err - pid->last_err));
184 result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
186 return (signed int)fp_toint(result);
189 static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
191 pid_p_gain_set(&cpu->pid, cpu->pstate_policy->p_gain_pct);
192 pid_d_gain_set(&cpu->pid, cpu->pstate_policy->d_gain_pct);
193 pid_i_gain_set(&cpu->pid, cpu->pstate_policy->i_gain_pct);
196 cpu->pstate_policy->setpoint,
198 cpu->pstate_policy->deadband,
202 static inline void intel_pstate_idle_pid_reset(struct cpudata *cpu)
204 pid_p_gain_set(&cpu->idle_pid, cpu->pstate_policy->p_gain_pct);
205 pid_d_gain_set(&cpu->idle_pid, cpu->pstate_policy->d_gain_pct);
206 pid_i_gain_set(&cpu->idle_pid, cpu->pstate_policy->i_gain_pct);
208 pid_reset(&cpu->idle_pid,
211 cpu->pstate_policy->deadband,
215 static inline void intel_pstate_reset_all_pid(void)
218 for_each_online_cpu(cpu) {
219 if (all_cpu_data[cpu])
220 intel_pstate_busy_pid_reset(all_cpu_data[cpu]);
224 /************************** debugfs begin ************************/
225 static int pid_param_set(void *data, u64 val)
228 intel_pstate_reset_all_pid();
231 static int pid_param_get(void *data, u64 *val)
236 DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get,
237 pid_param_set, "%llu\n");
244 static struct pid_param pid_files[] = {
245 {"sample_rate_ms", &default_policy.sample_rate_ms},
246 {"d_gain_pct", &default_policy.d_gain_pct},
247 {"i_gain_pct", &default_policy.i_gain_pct},
248 {"deadband", &default_policy.deadband},
249 {"setpoint", &default_policy.setpoint},
250 {"p_gain_pct", &default_policy.p_gain_pct},
254 static struct dentry *debugfs_parent;
255 static void intel_pstate_debug_expose_params(void)
259 debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
260 if (IS_ERR_OR_NULL(debugfs_parent))
262 while (pid_files[i].name) {
263 debugfs_create_file(pid_files[i].name, 0660,
264 debugfs_parent, pid_files[i].value,
270 /************************** debugfs end ************************/
272 /************************** sysfs begin ************************/
273 #define show_one(file_name, object) \
274 static ssize_t show_##file_name \
275 (struct kobject *kobj, struct attribute *attr, char *buf) \
277 return sprintf(buf, "%u\n", limits.object); \
280 static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
281 const char *buf, size_t count)
285 ret = sscanf(buf, "%u", &input);
288 limits.no_turbo = clamp_t(int, input, 0 , 1);
293 static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b,
294 const char *buf, size_t count)
298 ret = sscanf(buf, "%u", &input);
302 limits.max_sysfs_pct = clamp_t(int, input, 0 , 100);
303 limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
304 limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
308 static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
309 const char *buf, size_t count)
313 ret = sscanf(buf, "%u", &input);
316 limits.min_perf_pct = clamp_t(int, input, 0 , 100);
317 limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
322 show_one(no_turbo, no_turbo);
323 show_one(max_perf_pct, max_perf_pct);
324 show_one(min_perf_pct, min_perf_pct);
326 define_one_global_rw(no_turbo);
327 define_one_global_rw(max_perf_pct);
328 define_one_global_rw(min_perf_pct);
330 static struct attribute *intel_pstate_attributes[] = {
337 static struct attribute_group intel_pstate_attr_group = {
338 .attrs = intel_pstate_attributes,
340 static struct kobject *intel_pstate_kobject;
342 static void intel_pstate_sysfs_expose_params(void)
346 intel_pstate_kobject = kobject_create_and_add("intel_pstate",
347 &cpu_subsys.dev_root->kobj);
348 BUG_ON(!intel_pstate_kobject);
349 rc = sysfs_create_group(intel_pstate_kobject,
350 &intel_pstate_attr_group);
354 /************************** sysfs end ************************/
356 static int intel_pstate_min_pstate(void)
359 rdmsrl(MSR_PLATFORM_INFO, value);
360 return (value >> 40) & 0xFF;
363 static int intel_pstate_max_pstate(void)
366 rdmsrl(MSR_PLATFORM_INFO, value);
367 return (value >> 8) & 0xFF;
370 static int intel_pstate_turbo_pstate(void)
374 rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
375 nont = intel_pstate_max_pstate();
376 ret = ((value) & 255);
382 static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
384 int max_perf = cpu->pstate.turbo_pstate;
387 max_perf = cpu->pstate.max_pstate;
389 max_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.max_perf));
390 *max = clamp_t(int, max_perf,
391 cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
393 min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.min_perf));
394 *min = clamp_t(int, min_perf,
395 cpu->pstate.min_pstate, max_perf);
398 static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
400 int max_perf, min_perf;
402 intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
404 pstate = clamp_t(int, pstate, min_perf, max_perf);
406 if (pstate == cpu->pstate.current_pstate)
410 trace_cpu_frequency(pstate * 100000, cpu->cpu);
412 cpu->pstate.current_pstate = pstate;
413 wrmsrl(MSR_IA32_PERF_CTL, pstate << 8);
417 static inline void intel_pstate_pstate_increase(struct cpudata *cpu, int steps)
420 target = cpu->pstate.current_pstate + steps;
422 intel_pstate_set_pstate(cpu, target);
425 static inline void intel_pstate_pstate_decrease(struct cpudata *cpu, int steps)
428 target = cpu->pstate.current_pstate - steps;
429 intel_pstate_set_pstate(cpu, target);
432 static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
434 sprintf(cpu->name, "Intel 2nd generation core");
436 cpu->pstate.min_pstate = intel_pstate_min_pstate();
437 cpu->pstate.max_pstate = intel_pstate_max_pstate();
438 cpu->pstate.turbo_pstate = intel_pstate_turbo_pstate();
441 * goto max pstate so we don't slow up boot if we are built-in if we are
442 * a module we will take care of it during normal operation
444 intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
447 static inline void intel_pstate_calc_busy(struct cpudata *cpu,
448 struct sample *sample)
451 core_pct = div64_u64(sample->aperf * 100, sample->mperf);
452 sample->freq = cpu->pstate.max_pstate * core_pct * 1000;
454 sample->core_pct_busy = core_pct;
457 static inline void intel_pstate_sample(struct cpudata *cpu)
461 rdmsrl(MSR_IA32_APERF, aperf);
462 rdmsrl(MSR_IA32_MPERF, mperf);
463 cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
464 cpu->samples[cpu->sample_ptr].aperf = aperf;
465 cpu->samples[cpu->sample_ptr].mperf = mperf;
466 cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
467 cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
469 intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
471 cpu->prev_aperf = aperf;
472 cpu->prev_mperf = mperf;
475 static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
477 int sample_time, delay;
479 sample_time = cpu->pstate_policy->sample_rate_ms;
480 delay = msecs_to_jiffies(sample_time);
481 mod_timer_pinned(&cpu->timer, jiffies + delay);
484 static inline void intel_pstate_idle_mode(struct cpudata *cpu)
489 static inline void intel_pstate_normal_mode(struct cpudata *cpu)
494 static inline int intel_pstate_get_scaled_busy(struct cpudata *cpu)
497 int32_t core_busy, turbo_pstate, current_pstate;
499 core_busy = int_tofp(cpu->samples[cpu->sample_ptr].core_pct_busy);
500 turbo_pstate = int_tofp(cpu->pstate.turbo_pstate);
501 current_pstate = int_tofp(cpu->pstate.current_pstate);
502 busy_scaled = mul_fp(core_busy, div_fp(turbo_pstate, current_pstate));
504 return fp_toint(busy_scaled);
507 static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
515 busy_scaled = intel_pstate_get_scaled_busy(cpu);
517 ctl = pid_calc(pid, busy_scaled);
521 intel_pstate_pstate_increase(cpu, steps);
523 intel_pstate_pstate_decrease(cpu, steps);
526 static inline void intel_pstate_adjust_idle_pstate(struct cpudata *cpu)
533 pid = &cpu->idle_pid;
535 busy_scaled = intel_pstate_get_scaled_busy(cpu);
537 ctl = pid_calc(pid, 100 - busy_scaled);
541 intel_pstate_pstate_decrease(cpu, steps);
543 intel_pstate_pstate_increase(cpu, steps);
545 if (cpu->pstate.current_pstate == cpu->pstate.min_pstate)
546 intel_pstate_normal_mode(cpu);
549 static void intel_pstate_timer_func(unsigned long __data)
551 struct cpudata *cpu = (struct cpudata *) __data;
553 intel_pstate_sample(cpu);
554 intel_pstate_adjust_busy_pstate(cpu);
556 if (cpu->pstate.current_pstate == cpu->pstate.min_pstate) {
557 cpu->min_pstate_count++;
558 if (!(cpu->min_pstate_count % 5)) {
559 intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
562 cpu->min_pstate_count = 0;
564 intel_pstate_set_sample_time(cpu);
567 #define ICPU(model, policy) \
568 { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&policy }
570 static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
571 ICPU(0x2a, default_policy),
572 ICPU(0x2d, default_policy),
575 MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
577 static int intel_pstate_init_cpu(unsigned int cpunum)
580 const struct x86_cpu_id *id;
583 id = x86_match_cpu(intel_pstate_cpu_ids);
587 all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
588 if (!all_cpu_data[cpunum])
591 cpu = all_cpu_data[cpunum];
593 intel_pstate_get_cpu_pstates(cpu);
597 (struct pstate_adjust_policy *)id->driver_data;
598 init_timer_deferrable(&cpu->timer);
599 cpu->timer.function = intel_pstate_timer_func;
602 cpu->timer.expires = jiffies + HZ/100;
603 intel_pstate_busy_pid_reset(cpu);
604 intel_pstate_idle_pid_reset(cpu);
605 intel_pstate_sample(cpu);
606 intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
608 add_timer_on(&cpu->timer, cpunum);
610 pr_info("Intel pstate controlling: cpu %d\n", cpunum);
615 static unsigned int intel_pstate_get(unsigned int cpu_num)
617 struct sample *sample;
620 cpu = all_cpu_data[cpu_num];
623 sample = &cpu->samples[cpu->sample_ptr];
627 static int intel_pstate_set_policy(struct cpufreq_policy *policy)
631 cpu = all_cpu_data[policy->cpu];
633 if (!policy->cpuinfo.max_freq)
636 if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
637 limits.min_perf_pct = 100;
638 limits.min_perf = int_tofp(1);
639 limits.max_perf_pct = 100;
640 limits.max_perf = int_tofp(1);
644 limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
645 limits.min_perf_pct = clamp_t(int, limits.min_perf_pct, 0 , 100);
646 limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
648 limits.max_policy_pct = policy->max * 100 / policy->cpuinfo.max_freq;
649 limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100);
650 limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
651 limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
656 static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
658 cpufreq_verify_within_limits(policy,
659 policy->cpuinfo.min_freq,
660 policy->cpuinfo.max_freq);
662 if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
663 (policy->policy != CPUFREQ_POLICY_PERFORMANCE))
669 static int __cpuinit intel_pstate_cpu_exit(struct cpufreq_policy *policy)
671 int cpu = policy->cpu;
673 del_timer(&all_cpu_data[cpu]->timer);
674 kfree(all_cpu_data[cpu]);
675 all_cpu_data[cpu] = NULL;
679 static int __cpuinit intel_pstate_cpu_init(struct cpufreq_policy *policy)
681 int rc, min_pstate, max_pstate;
684 rc = intel_pstate_init_cpu(policy->cpu);
688 cpu = all_cpu_data[policy->cpu];
690 if (!limits.no_turbo &&
691 limits.min_perf_pct == 100 && limits.max_perf_pct == 100)
692 policy->policy = CPUFREQ_POLICY_PERFORMANCE;
694 policy->policy = CPUFREQ_POLICY_POWERSAVE;
696 intel_pstate_get_min_max(cpu, &min_pstate, &max_pstate);
697 policy->min = min_pstate * 100000;
698 policy->max = max_pstate * 100000;
700 /* cpuinfo and default policy values */
701 policy->cpuinfo.min_freq = cpu->pstate.min_pstate * 100000;
702 policy->cpuinfo.max_freq = cpu->pstate.turbo_pstate * 100000;
703 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
704 cpumask_set_cpu(policy->cpu, policy->cpus);
709 static struct cpufreq_driver intel_pstate_driver = {
710 .flags = CPUFREQ_CONST_LOOPS,
711 .verify = intel_pstate_verify_policy,
712 .setpolicy = intel_pstate_set_policy,
713 .get = intel_pstate_get,
714 .init = intel_pstate_cpu_init,
715 .exit = intel_pstate_cpu_exit,
716 .name = "intel_pstate",
717 .owner = THIS_MODULE,
720 static int __initdata no_load;
722 static int intel_pstate_msrs_not_valid(void)
724 /* Check that all the msr's we are using are valid. */
725 u64 aperf, mperf, tmp;
727 rdmsrl(MSR_IA32_APERF, aperf);
728 rdmsrl(MSR_IA32_MPERF, mperf);
730 if (!intel_pstate_min_pstate() ||
731 !intel_pstate_max_pstate() ||
732 !intel_pstate_turbo_pstate())
735 rdmsrl(MSR_IA32_APERF, tmp);
739 rdmsrl(MSR_IA32_MPERF, tmp);
745 static int __init intel_pstate_init(void)
748 const struct x86_cpu_id *id;
753 id = x86_match_cpu(intel_pstate_cpu_ids);
757 if (intel_pstate_msrs_not_valid())
760 pr_info("Intel P-state driver initializing.\n");
762 all_cpu_data = vmalloc(sizeof(void *) * num_possible_cpus());
765 memset(all_cpu_data, 0, sizeof(void *) * num_possible_cpus());
767 rc = cpufreq_register_driver(&intel_pstate_driver);
771 intel_pstate_debug_expose_params();
772 intel_pstate_sysfs_expose_params();
776 for_each_online_cpu(cpu) {
777 if (all_cpu_data[cpu]) {
778 del_timer_sync(&all_cpu_data[cpu]->timer);
779 kfree(all_cpu_data[cpu]);
787 device_initcall(intel_pstate_init);
789 static int __init intel_pstate_setup(char *str)
794 if (!strcmp(str, "disable"))
798 early_param("intel_pstate", intel_pstate_setup);
800 MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@intel.com>");
801 MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
802 MODULE_LICENSE("GPL");