linux/drivers/cpufreq/intel_pstate.c
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   1/*
   2 * intel_pstate.c: Native P state management for Intel processors
   3 *
   4 * (C) Copyright 2012 Intel Corporation
   5 * Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
   6 *
   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
  10 * of the License.
  11 */
  12
  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>
  26#include <linux/fs.h>
  27#include <linux/debugfs.h>
  28#include <trace/events/power.h>
  29
  30#include <asm/div64.h>
  31#include <asm/msr.h>
  32#include <asm/cpu_device_id.h>
  33
  34#define SAMPLE_COUNT            3
  35
  36#define FRAC_BITS 8
  37#define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
  38#define fp_toint(X) ((X) >> FRAC_BITS)
  39
  40static inline int32_t mul_fp(int32_t x, int32_t y)
  41{
  42        return ((int64_t)x * (int64_t)y) >> FRAC_BITS;
  43}
  44
  45static inline int32_t div_fp(int32_t x, int32_t y)
  46{
  47        return div_s64((int64_t)x << FRAC_BITS, (int64_t)y);
  48}
  49
  50struct sample {
  51        int core_pct_busy;
  52        u64 aperf;
  53        u64 mperf;
  54        int freq;
  55};
  56
  57struct pstate_data {
  58        int     current_pstate;
  59        int     min_pstate;
  60        int     max_pstate;
  61        int     turbo_pstate;
  62};
  63
  64struct _pid {
  65        int setpoint;
  66        int32_t integral;
  67        int32_t p_gain;
  68        int32_t i_gain;
  69        int32_t d_gain;
  70        int deadband;
  71        int last_err;
  72};
  73
  74struct cpudata {
  75        int cpu;
  76
  77        char name[64];
  78
  79        struct timer_list timer;
  80
  81        struct pstate_adjust_policy *pstate_policy;
  82        struct pstate_data pstate;
  83        struct _pid pid;
  84
  85        int min_pstate_count;
  86
  87        u64     prev_aperf;
  88        u64     prev_mperf;
  89        int     sample_ptr;
  90        struct sample samples[SAMPLE_COUNT];
  91};
  92
  93static struct cpudata **all_cpu_data;
  94struct pstate_adjust_policy {
  95        int sample_rate_ms;
  96        int deadband;
  97        int setpoint;
  98        int p_gain_pct;
  99        int d_gain_pct;
 100        int i_gain_pct;
 101};
 102
 103static struct pstate_adjust_policy default_policy = {
 104        .sample_rate_ms = 10,
 105        .deadband = 0,
 106        .setpoint = 97,
 107        .p_gain_pct = 20,
 108        .d_gain_pct = 0,
 109        .i_gain_pct = 0,
 110};
 111
 112struct perf_limits {
 113        int no_turbo;
 114        int max_perf_pct;
 115        int min_perf_pct;
 116        int32_t max_perf;
 117        int32_t min_perf;
 118        int max_policy_pct;
 119        int max_sysfs_pct;
 120};
 121
 122static struct perf_limits limits = {
 123        .no_turbo = 0,
 124        .max_perf_pct = 100,
 125        .max_perf = int_tofp(1),
 126        .min_perf_pct = 0,
 127        .min_perf = 0,
 128        .max_policy_pct = 100,
 129        .max_sysfs_pct = 100,
 130};
 131
 132static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
 133                        int deadband, int integral) {
 134        pid->setpoint = setpoint;
 135        pid->deadband  = deadband;
 136        pid->integral  = int_tofp(integral);
 137        pid->last_err  = setpoint - busy;
 138}
 139
 140static inline void pid_p_gain_set(struct _pid *pid, int percent)
 141{
 142        pid->p_gain = div_fp(int_tofp(percent), int_tofp(100));
 143}
 144
 145static inline void pid_i_gain_set(struct _pid *pid, int percent)
 146{
 147        pid->i_gain = div_fp(int_tofp(percent), int_tofp(100));
 148}
 149
 150static inline void pid_d_gain_set(struct _pid *pid, int percent)
 151{
 152
 153        pid->d_gain = div_fp(int_tofp(percent), int_tofp(100));
 154}
 155
 156static signed int pid_calc(struct _pid *pid, int busy)
 157{
 158        signed int err, result;
 159        int32_t pterm, dterm, fp_error;
 160        int32_t integral_limit;
 161
 162        err = pid->setpoint - busy;
 163        fp_error = int_tofp(err);
 164
 165        if (abs(err) <= pid->deadband)
 166                return 0;
 167
 168        pterm = mul_fp(pid->p_gain, fp_error);
 169
 170        pid->integral += fp_error;
 171
 172        /* limit the integral term */
 173        integral_limit = int_tofp(30);
 174        if (pid->integral > integral_limit)
 175                pid->integral = integral_limit;
 176        if (pid->integral < -integral_limit)
 177                pid->integral = -integral_limit;
 178
 179        dterm = mul_fp(pid->d_gain, (err - pid->last_err));
 180        pid->last_err = err;
 181
 182        result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
 183
 184        return (signed int)fp_toint(result);
 185}
 186
 187static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
 188{
 189        pid_p_gain_set(&cpu->pid, cpu->pstate_policy->p_gain_pct);
 190        pid_d_gain_set(&cpu->pid, cpu->pstate_policy->d_gain_pct);
 191        pid_i_gain_set(&cpu->pid, cpu->pstate_policy->i_gain_pct);
 192
 193        pid_reset(&cpu->pid,
 194                cpu->pstate_policy->setpoint,
 195                100,
 196                cpu->pstate_policy->deadband,
 197                0);
 198}
 199
 200static inline void intel_pstate_reset_all_pid(void)
 201{
 202        unsigned int cpu;
 203        for_each_online_cpu(cpu) {
 204                if (all_cpu_data[cpu])
 205                        intel_pstate_busy_pid_reset(all_cpu_data[cpu]);
 206        }
 207}
 208
 209/************************** debugfs begin ************************/
 210static int pid_param_set(void *data, u64 val)
 211{
 212        *(u32 *)data = val;
 213        intel_pstate_reset_all_pid();
 214        return 0;
 215}
 216static int pid_param_get(void *data, u64 *val)
 217{
 218        *val = *(u32 *)data;
 219        return 0;
 220}
 221DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get,
 222                        pid_param_set, "%llu\n");
 223
 224struct pid_param {
 225        char *name;
 226        void *value;
 227};
 228
 229static struct pid_param pid_files[] = {
 230        {"sample_rate_ms", &default_policy.sample_rate_ms},
 231        {"d_gain_pct", &default_policy.d_gain_pct},
 232        {"i_gain_pct", &default_policy.i_gain_pct},
 233        {"deadband", &default_policy.deadband},
 234        {"setpoint", &default_policy.setpoint},
 235        {"p_gain_pct", &default_policy.p_gain_pct},
 236        {NULL, NULL}
 237};
 238
 239static struct dentry *debugfs_parent;
 240static void intel_pstate_debug_expose_params(void)
 241{
 242        int i = 0;
 243
 244        debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
 245        if (IS_ERR_OR_NULL(debugfs_parent))
 246                return;
 247        while (pid_files[i].name) {
 248                debugfs_create_file(pid_files[i].name, 0660,
 249                                debugfs_parent, pid_files[i].value,
 250                                &fops_pid_param);
 251                i++;
 252        }
 253}
 254
 255/************************** debugfs end ************************/
 256
 257/************************** sysfs begin ************************/
 258#define show_one(file_name, object)                                     \
 259        static ssize_t show_##file_name                                 \
 260        (struct kobject *kobj, struct attribute *attr, char *buf)       \
 261        {                                                               \
 262                return sprintf(buf, "%u\n", limits.object);             \
 263        }
 264
 265static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
 266                                const char *buf, size_t count)
 267{
 268        unsigned int input;
 269        int ret;
 270        ret = sscanf(buf, "%u", &input);
 271        if (ret != 1)
 272                return -EINVAL;
 273        limits.no_turbo = clamp_t(int, input, 0 , 1);
 274
 275        return count;
 276}
 277
 278static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b,
 279                                const char *buf, size_t count)
 280{
 281        unsigned int input;
 282        int ret;
 283        ret = sscanf(buf, "%u", &input);
 284        if (ret != 1)
 285                return -EINVAL;
 286
 287        limits.max_sysfs_pct = clamp_t(int, input, 0 , 100);
 288        limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
 289        limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
 290        return count;
 291}
 292
 293static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
 294                                const char *buf, size_t count)
 295{
 296        unsigned int input;
 297        int ret;
 298        ret = sscanf(buf, "%u", &input);
 299        if (ret != 1)
 300                return -EINVAL;
 301        limits.min_perf_pct = clamp_t(int, input, 0 , 100);
 302        limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
 303
 304        return count;
 305}
 306
 307show_one(no_turbo, no_turbo);
 308show_one(max_perf_pct, max_perf_pct);
 309show_one(min_perf_pct, min_perf_pct);
 310
 311define_one_global_rw(no_turbo);
 312define_one_global_rw(max_perf_pct);
 313define_one_global_rw(min_perf_pct);
 314
 315static struct attribute *intel_pstate_attributes[] = {
 316        &no_turbo.attr,
 317        &max_perf_pct.attr,
 318        &min_perf_pct.attr,
 319        NULL
 320};
 321
 322static struct attribute_group intel_pstate_attr_group = {
 323        .attrs = intel_pstate_attributes,
 324};
 325static struct kobject *intel_pstate_kobject;
 326
 327static void intel_pstate_sysfs_expose_params(void)
 328{
 329        int rc;
 330
 331        intel_pstate_kobject = kobject_create_and_add("intel_pstate",
 332                                                &cpu_subsys.dev_root->kobj);
 333        BUG_ON(!intel_pstate_kobject);
 334        rc = sysfs_create_group(intel_pstate_kobject,
 335                                &intel_pstate_attr_group);
 336        BUG_ON(rc);
 337}
 338
 339/************************** sysfs end ************************/
 340
 341static int intel_pstate_min_pstate(void)
 342{
 343        u64 value;
 344        rdmsrl(MSR_PLATFORM_INFO, value);
 345        return (value >> 40) & 0xFF;
 346}
 347
 348static int intel_pstate_max_pstate(void)
 349{
 350        u64 value;
 351        rdmsrl(MSR_PLATFORM_INFO, value);
 352        return (value >> 8) & 0xFF;
 353}
 354
 355static int intel_pstate_turbo_pstate(void)
 356{
 357        u64 value;
 358        int nont, ret;
 359        rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
 360        nont = intel_pstate_max_pstate();
 361        ret = ((value) & 255);
 362        if (ret <= nont)
 363                ret = nont;
 364        return ret;
 365}
 366
 367static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
 368{
 369        int max_perf = cpu->pstate.turbo_pstate;
 370        int min_perf;
 371        if (limits.no_turbo)
 372                max_perf = cpu->pstate.max_pstate;
 373
 374        max_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.max_perf));
 375        *max = clamp_t(int, max_perf,
 376                        cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
 377
 378        min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.min_perf));
 379        *min = clamp_t(int, min_perf,
 380                        cpu->pstate.min_pstate, max_perf);
 381}
 382
 383static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
 384{
 385        int max_perf, min_perf;
 386
 387        intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
 388
 389        pstate = clamp_t(int, pstate, min_perf, max_perf);
 390
 391        if (pstate == cpu->pstate.current_pstate)
 392                return;
 393
 394        trace_cpu_frequency(pstate * 100000, cpu->cpu);
 395
 396        cpu->pstate.current_pstate = pstate;
 397        wrmsrl(MSR_IA32_PERF_CTL, pstate << 8);
 398
 399}
 400
 401static inline void intel_pstate_pstate_increase(struct cpudata *cpu, int steps)
 402{
 403        int target;
 404        target = cpu->pstate.current_pstate + steps;
 405
 406        intel_pstate_set_pstate(cpu, target);
 407}
 408
 409static inline void intel_pstate_pstate_decrease(struct cpudata *cpu, int steps)
 410{
 411        int target;
 412        target = cpu->pstate.current_pstate - steps;
 413        intel_pstate_set_pstate(cpu, target);
 414}
 415
 416static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
 417{
 418        sprintf(cpu->name, "Intel 2nd generation core");
 419
 420        cpu->pstate.min_pstate = intel_pstate_min_pstate();
 421        cpu->pstate.max_pstate = intel_pstate_max_pstate();
 422        cpu->pstate.turbo_pstate = intel_pstate_turbo_pstate();
 423
 424        /*
 425         * goto max pstate so we don't slow up boot if we are built-in if we are
 426         * a module we will take care of it during normal operation
 427         */
 428        intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 429}
 430
 431static inline void intel_pstate_calc_busy(struct cpudata *cpu,
 432                                        struct sample *sample)
 433{
 434        u64 core_pct;
 435        core_pct = div64_u64(sample->aperf * 100, sample->mperf);
 436        sample->freq = cpu->pstate.max_pstate * core_pct * 1000;
 437
 438        sample->core_pct_busy = core_pct;
 439}
 440
 441static inline void intel_pstate_sample(struct cpudata *cpu)
 442{
 443        u64 aperf, mperf;
 444
 445        rdmsrl(MSR_IA32_APERF, aperf);
 446        rdmsrl(MSR_IA32_MPERF, mperf);
 447        cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
 448        cpu->samples[cpu->sample_ptr].aperf = aperf;
 449        cpu->samples[cpu->sample_ptr].mperf = mperf;
 450        cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
 451        cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
 452
 453        intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
 454
 455        cpu->prev_aperf = aperf;
 456        cpu->prev_mperf = mperf;
 457}
 458
 459static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
 460{
 461        int sample_time, delay;
 462
 463        sample_time = cpu->pstate_policy->sample_rate_ms;
 464        delay = msecs_to_jiffies(sample_time);
 465        mod_timer_pinned(&cpu->timer, jiffies + delay);
 466}
 467
 468static inline int intel_pstate_get_scaled_busy(struct cpudata *cpu)
 469{
 470        int32_t busy_scaled;
 471        int32_t core_busy, max_pstate, current_pstate;
 472
 473        core_busy = int_tofp(cpu->samples[cpu->sample_ptr].core_pct_busy);
 474        max_pstate = int_tofp(cpu->pstate.max_pstate);
 475        current_pstate = int_tofp(cpu->pstate.current_pstate);
 476        busy_scaled = mul_fp(core_busy, div_fp(max_pstate, current_pstate));
 477
 478        return fp_toint(busy_scaled);
 479}
 480
 481static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
 482{
 483        int busy_scaled;
 484        struct _pid *pid;
 485        signed int ctl = 0;
 486        int steps;
 487
 488        pid = &cpu->pid;
 489        busy_scaled = intel_pstate_get_scaled_busy(cpu);
 490
 491        ctl = pid_calc(pid, busy_scaled);
 492
 493        steps = abs(ctl);
 494        if (ctl < 0)
 495                intel_pstate_pstate_increase(cpu, steps);
 496        else
 497                intel_pstate_pstate_decrease(cpu, steps);
 498}
 499
 500static void intel_pstate_timer_func(unsigned long __data)
 501{
 502        struct cpudata *cpu = (struct cpudata *) __data;
 503
 504        intel_pstate_sample(cpu);
 505        intel_pstate_adjust_busy_pstate(cpu);
 506
 507        if (cpu->pstate.current_pstate == cpu->pstate.min_pstate) {
 508                cpu->min_pstate_count++;
 509                if (!(cpu->min_pstate_count % 5)) {
 510                        intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 511                }
 512        } else
 513                cpu->min_pstate_count = 0;
 514
 515        intel_pstate_set_sample_time(cpu);
 516}
 517
 518#define ICPU(model, policy) \
 519        { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&policy }
 520
 521static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
 522        ICPU(0x2a, default_policy),
 523        ICPU(0x2d, default_policy),
 524        ICPU(0x3a, default_policy),
 525        {}
 526};
 527MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
 528
 529static int intel_pstate_init_cpu(unsigned int cpunum)
 530{
 531
 532        const struct x86_cpu_id *id;
 533        struct cpudata *cpu;
 534
 535        id = x86_match_cpu(intel_pstate_cpu_ids);
 536        if (!id)
 537                return -ENODEV;
 538
 539        all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
 540        if (!all_cpu_data[cpunum])
 541                return -ENOMEM;
 542
 543        cpu = all_cpu_data[cpunum];
 544
 545        intel_pstate_get_cpu_pstates(cpu);
 546
 547        cpu->cpu = cpunum;
 548        cpu->pstate_policy =
 549                (struct pstate_adjust_policy *)id->driver_data;
 550        init_timer_deferrable(&cpu->timer);
 551        cpu->timer.function = intel_pstate_timer_func;
 552        cpu->timer.data =
 553                (unsigned long)cpu;
 554        cpu->timer.expires = jiffies + HZ/100;
 555        intel_pstate_busy_pid_reset(cpu);
 556        intel_pstate_sample(cpu);
 557        intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 558
 559        add_timer_on(&cpu->timer, cpunum);
 560
 561        pr_info("Intel pstate controlling: cpu %d\n", cpunum);
 562
 563        return 0;
 564}
 565
 566static unsigned int intel_pstate_get(unsigned int cpu_num)
 567{
 568        struct sample *sample;
 569        struct cpudata *cpu;
 570
 571        cpu = all_cpu_data[cpu_num];
 572        if (!cpu)
 573                return 0;
 574        sample = &cpu->samples[cpu->sample_ptr];
 575        return sample->freq;
 576}
 577
 578static int intel_pstate_set_policy(struct cpufreq_policy *policy)
 579{
 580        struct cpudata *cpu;
 581
 582        cpu = all_cpu_data[policy->cpu];
 583
 584        if (!policy->cpuinfo.max_freq)
 585                return -ENODEV;
 586
 587        if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
 588                limits.min_perf_pct = 100;
 589                limits.min_perf = int_tofp(1);
 590                limits.max_perf_pct = 100;
 591                limits.max_perf = int_tofp(1);
 592                limits.no_turbo = 0;
 593                return 0;
 594        }
 595        limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
 596        limits.min_perf_pct = clamp_t(int, limits.min_perf_pct, 0 , 100);
 597        limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
 598
 599        limits.max_policy_pct = policy->max * 100 / policy->cpuinfo.max_freq;
 600        limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100);
 601        limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
 602        limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
 603
 604        return 0;
 605}
 606
 607static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
 608{
 609        cpufreq_verify_within_limits(policy,
 610                                policy->cpuinfo.min_freq,
 611                                policy->cpuinfo.max_freq);
 612
 613        if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
 614                (policy->policy != CPUFREQ_POLICY_PERFORMANCE))
 615                return -EINVAL;
 616
 617        return 0;
 618}
 619
 620static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
 621{
 622        int cpu = policy->cpu;
 623
 624        del_timer(&all_cpu_data[cpu]->timer);
 625        kfree(all_cpu_data[cpu]);
 626        all_cpu_data[cpu] = NULL;
 627        return 0;
 628}
 629
 630static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
 631{
 632        int rc, min_pstate, max_pstate;
 633        struct cpudata *cpu;
 634
 635        rc = intel_pstate_init_cpu(policy->cpu);
 636        if (rc)
 637                return rc;
 638
 639        cpu = all_cpu_data[policy->cpu];
 640
 641        if (!limits.no_turbo &&
 642                limits.min_perf_pct == 100 && limits.max_perf_pct == 100)
 643                policy->policy = CPUFREQ_POLICY_PERFORMANCE;
 644        else
 645                policy->policy = CPUFREQ_POLICY_POWERSAVE;
 646
 647        intel_pstate_get_min_max(cpu, &min_pstate, &max_pstate);
 648        policy->min = min_pstate * 100000;
 649        policy->max = max_pstate * 100000;
 650
 651        /* cpuinfo and default policy values */
 652        policy->cpuinfo.min_freq = cpu->pstate.min_pstate * 100000;
 653        policy->cpuinfo.max_freq = cpu->pstate.turbo_pstate * 100000;
 654        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 655        cpumask_set_cpu(policy->cpu, policy->cpus);
 656
 657        return 0;
 658}
 659
 660static struct cpufreq_driver intel_pstate_driver = {
 661        .flags          = CPUFREQ_CONST_LOOPS,
 662        .verify         = intel_pstate_verify_policy,
 663        .setpolicy      = intel_pstate_set_policy,
 664        .get            = intel_pstate_get,
 665        .init           = intel_pstate_cpu_init,
 666        .exit           = intel_pstate_cpu_exit,
 667        .name           = "intel_pstate",
 668        .owner          = THIS_MODULE,
 669};
 670
 671static int __initdata no_load;
 672
 673static int intel_pstate_msrs_not_valid(void)
 674{
 675        /* Check that all the msr's we are using are valid. */
 676        u64 aperf, mperf, tmp;
 677
 678        rdmsrl(MSR_IA32_APERF, aperf);
 679        rdmsrl(MSR_IA32_MPERF, mperf);
 680
 681        if (!intel_pstate_min_pstate() ||
 682                !intel_pstate_max_pstate() ||
 683                !intel_pstate_turbo_pstate())
 684                return -ENODEV;
 685
 686        rdmsrl(MSR_IA32_APERF, tmp);
 687        if (!(tmp - aperf))
 688                return -ENODEV;
 689
 690        rdmsrl(MSR_IA32_MPERF, tmp);
 691        if (!(tmp - mperf))
 692                return -ENODEV;
 693
 694        return 0;
 695}
 696static int __init intel_pstate_init(void)
 697{
 698        int cpu, rc = 0;
 699        const struct x86_cpu_id *id;
 700
 701        if (no_load)
 702                return -ENODEV;
 703
 704        id = x86_match_cpu(intel_pstate_cpu_ids);
 705        if (!id)
 706                return -ENODEV;
 707
 708        if (intel_pstate_msrs_not_valid())
 709                return -ENODEV;
 710
 711        pr_info("Intel P-state driver initializing.\n");
 712
 713        all_cpu_data = vzalloc(sizeof(void *) * num_possible_cpus());
 714        if (!all_cpu_data)
 715                return -ENOMEM;
 716
 717        rc = cpufreq_register_driver(&intel_pstate_driver);
 718        if (rc)
 719                goto out;
 720
 721        intel_pstate_debug_expose_params();
 722        intel_pstate_sysfs_expose_params();
 723        return rc;
 724out:
 725        get_online_cpus();
 726        for_each_online_cpu(cpu) {
 727                if (all_cpu_data[cpu]) {
 728                        del_timer_sync(&all_cpu_data[cpu]->timer);
 729                        kfree(all_cpu_data[cpu]);
 730                }
 731        }
 732
 733        put_online_cpus();
 734        vfree(all_cpu_data);
 735        return -ENODEV;
 736}
 737device_initcall(intel_pstate_init);
 738
 739static int __init intel_pstate_setup(char *str)
 740{
 741        if (!str)
 742                return -EINVAL;
 743
 744        if (!strcmp(str, "disable"))
 745                no_load = 1;
 746        return 0;
 747}
 748early_param("intel_pstate", intel_pstate_setup);
 749
 750MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@intel.com>");
 751MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
 752MODULE_LICENSE("GPL");
 753
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