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        int32_t 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        int32_t 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, int32_t busy)
 157{
 158        signed int result;
 159        int32_t pterm, dterm, fp_error;
 160        int32_t integral_limit;
 161
 162        fp_error = int_tofp(pid->setpoint) - busy;
 163
 164        if (abs(fp_error) <= int_tofp(pid->deadband))
 165                return 0;
 166
 167        pterm = mul_fp(pid->p_gain, fp_error);
 168
 169        pid->integral += fp_error;
 170
 171        /* limit the integral term */
 172        integral_limit = int_tofp(30);
 173        if (pid->integral > integral_limit)
 174                pid->integral = integral_limit;
 175        if (pid->integral < -integral_limit)
 176                pid->integral = -integral_limit;
 177
 178        dterm = mul_fp(pid->d_gain, fp_error - pid->last_err);
 179        pid->last_err = fp_error;
 180
 181        result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
 182
 183        return (signed int)fp_toint(result);
 184}
 185
 186static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
 187{
 188        pid_p_gain_set(&cpu->pid, cpu->pstate_policy->p_gain_pct);
 189        pid_d_gain_set(&cpu->pid, cpu->pstate_policy->d_gain_pct);
 190        pid_i_gain_set(&cpu->pid, cpu->pstate_policy->i_gain_pct);
 191
 192        pid_reset(&cpu->pid,
 193                cpu->pstate_policy->setpoint,
 194                100,
 195                cpu->pstate_policy->deadband,
 196                0);
 197}
 198
 199static inline void intel_pstate_reset_all_pid(void)
 200{
 201        unsigned int cpu;
 202        for_each_online_cpu(cpu) {
 203                if (all_cpu_data[cpu])
 204                        intel_pstate_busy_pid_reset(all_cpu_data[cpu]);
 205        }
 206}
 207
 208/************************** debugfs begin ************************/
 209static int pid_param_set(void *data, u64 val)
 210{
 211        *(u32 *)data = val;
 212        intel_pstate_reset_all_pid();
 213        return 0;
 214}
 215static int pid_param_get(void *data, u64 *val)
 216{
 217        *val = *(u32 *)data;
 218        return 0;
 219}
 220DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get,
 221                        pid_param_set, "%llu\n");
 222
 223struct pid_param {
 224        char *name;
 225        void *value;
 226};
 227
 228static struct pid_param pid_files[] = {
 229        {"sample_rate_ms", &default_policy.sample_rate_ms},
 230        {"d_gain_pct", &default_policy.d_gain_pct},
 231        {"i_gain_pct", &default_policy.i_gain_pct},
 232        {"deadband", &default_policy.deadband},
 233        {"setpoint", &default_policy.setpoint},
 234        {"p_gain_pct", &default_policy.p_gain_pct},
 235        {NULL, NULL}
 236};
 237
 238static struct dentry *debugfs_parent;
 239static void intel_pstate_debug_expose_params(void)
 240{
 241        int i = 0;
 242
 243        debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
 244        if (IS_ERR_OR_NULL(debugfs_parent))
 245                return;
 246        while (pid_files[i].name) {
 247                debugfs_create_file(pid_files[i].name, 0660,
 248                                debugfs_parent, pid_files[i].value,
 249                                &fops_pid_param);
 250                i++;
 251        }
 252}
 253
 254/************************** debugfs end ************************/
 255
 256/************************** sysfs begin ************************/
 257#define show_one(file_name, object)                                     \
 258        static ssize_t show_##file_name                                 \
 259        (struct kobject *kobj, struct attribute *attr, char *buf)       \
 260        {                                                               \
 261                return sprintf(buf, "%u\n", limits.object);             \
 262        }
 263
 264static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
 265                                const char *buf, size_t count)
 266{
 267        unsigned int input;
 268        int ret;
 269        ret = sscanf(buf, "%u", &input);
 270        if (ret != 1)
 271                return -EINVAL;
 272        limits.no_turbo = clamp_t(int, input, 0 , 1);
 273
 274        return count;
 275}
 276
 277static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b,
 278                                const char *buf, size_t count)
 279{
 280        unsigned int input;
 281        int ret;
 282        ret = sscanf(buf, "%u", &input);
 283        if (ret != 1)
 284                return -EINVAL;
 285
 286        limits.max_sysfs_pct = clamp_t(int, input, 0 , 100);
 287        limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
 288        limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
 289        return count;
 290}
 291
 292static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
 293                                const char *buf, size_t count)
 294{
 295        unsigned int input;
 296        int ret;
 297        ret = sscanf(buf, "%u", &input);
 298        if (ret != 1)
 299                return -EINVAL;
 300        limits.min_perf_pct = clamp_t(int, input, 0 , 100);
 301        limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
 302
 303        return count;
 304}
 305
 306show_one(no_turbo, no_turbo);
 307show_one(max_perf_pct, max_perf_pct);
 308show_one(min_perf_pct, min_perf_pct);
 309
 310define_one_global_rw(no_turbo);
 311define_one_global_rw(max_perf_pct);
 312define_one_global_rw(min_perf_pct);
 313
 314static struct attribute *intel_pstate_attributes[] = {
 315        &no_turbo.attr,
 316        &max_perf_pct.attr,
 317        &min_perf_pct.attr,
 318        NULL
 319};
 320
 321static struct attribute_group intel_pstate_attr_group = {
 322        .attrs = intel_pstate_attributes,
 323};
 324static struct kobject *intel_pstate_kobject;
 325
 326static void intel_pstate_sysfs_expose_params(void)
 327{
 328        int rc;
 329
 330        intel_pstate_kobject = kobject_create_and_add("intel_pstate",
 331                                                &cpu_subsys.dev_root->kobj);
 332        BUG_ON(!intel_pstate_kobject);
 333        rc = sysfs_create_group(intel_pstate_kobject,
 334                                &intel_pstate_attr_group);
 335        BUG_ON(rc);
 336}
 337
 338/************************** sysfs end ************************/
 339
 340static int intel_pstate_min_pstate(void)
 341{
 342        u64 value;
 343        rdmsrl(MSR_PLATFORM_INFO, value);
 344        return (value >> 40) & 0xFF;
 345}
 346
 347static int intel_pstate_max_pstate(void)
 348{
 349        u64 value;
 350        rdmsrl(MSR_PLATFORM_INFO, value);
 351        return (value >> 8) & 0xFF;
 352}
 353
 354static int intel_pstate_turbo_pstate(void)
 355{
 356        u64 value;
 357        int nont, ret;
 358        rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
 359        nont = intel_pstate_max_pstate();
 360        ret = ((value) & 255);
 361        if (ret <= nont)
 362                ret = nont;
 363        return ret;
 364}
 365
 366static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
 367{
 368        int max_perf = cpu->pstate.turbo_pstate;
 369        int max_perf_adj;
 370        int min_perf;
 371        if (limits.no_turbo)
 372                max_perf = cpu->pstate.max_pstate;
 373
 374        max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits.max_perf));
 375        *max = clamp_t(int, max_perf_adj,
 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        u64 val;
 387
 388        intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
 389
 390        pstate = clamp_t(int, pstate, min_perf, max_perf);
 391
 392        if (pstate == cpu->pstate.current_pstate)
 393                return;
 394
 395        trace_cpu_frequency(pstate * 100000, cpu->cpu);
 396
 397        cpu->pstate.current_pstate = pstate;
 398        val = pstate << 8;
 399        if (limits.no_turbo)
 400                val |= (u64)1 << 32;
 401
 402        wrmsrl(MSR_IA32_PERF_CTL, val);
 403}
 404
 405static inline void intel_pstate_pstate_increase(struct cpudata *cpu, int steps)
 406{
 407        int target;
 408        target = cpu->pstate.current_pstate + steps;
 409
 410        intel_pstate_set_pstate(cpu, target);
 411}
 412
 413static inline void intel_pstate_pstate_decrease(struct cpudata *cpu, int steps)
 414{
 415        int target;
 416        target = cpu->pstate.current_pstate - steps;
 417        intel_pstate_set_pstate(cpu, target);
 418}
 419
 420static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
 421{
 422        sprintf(cpu->name, "Intel 2nd generation core");
 423
 424        cpu->pstate.min_pstate = intel_pstate_min_pstate();
 425        cpu->pstate.max_pstate = intel_pstate_max_pstate();
 426        cpu->pstate.turbo_pstate = intel_pstate_turbo_pstate();
 427
 428        /*
 429         * goto max pstate so we don't slow up boot if we are built-in if we are
 430         * a module we will take care of it during normal operation
 431         */
 432        intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 433}
 434
 435static inline void intel_pstate_calc_busy(struct cpudata *cpu,
 436                                        struct sample *sample)
 437{
 438        u64 core_pct;
 439        core_pct = div64_u64(int_tofp(sample->aperf * 100),
 440                             sample->mperf);
 441        sample->freq = fp_toint(cpu->pstate.max_pstate * core_pct * 1000);
 442
 443        sample->core_pct_busy = core_pct;
 444}
 445
 446static inline void intel_pstate_sample(struct cpudata *cpu)
 447{
 448        u64 aperf, mperf;
 449
 450        rdmsrl(MSR_IA32_APERF, aperf);
 451        rdmsrl(MSR_IA32_MPERF, mperf);
 452        cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
 453        cpu->samples[cpu->sample_ptr].aperf = aperf;
 454        cpu->samples[cpu->sample_ptr].mperf = mperf;
 455        cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
 456        cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
 457
 458        intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
 459
 460        cpu->prev_aperf = aperf;
 461        cpu->prev_mperf = mperf;
 462}
 463
 464static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
 465{
 466        int sample_time, delay;
 467
 468        sample_time = cpu->pstate_policy->sample_rate_ms;
 469        delay = msecs_to_jiffies(sample_time);
 470        mod_timer_pinned(&cpu->timer, jiffies + delay);
 471}
 472
 473static inline int32_t intel_pstate_get_scaled_busy(struct cpudata *cpu)
 474{
 475        int32_t core_busy, max_pstate, current_pstate;
 476
 477        core_busy = cpu->samples[cpu->sample_ptr].core_pct_busy;
 478        max_pstate = int_tofp(cpu->pstate.max_pstate);
 479        current_pstate = int_tofp(cpu->pstate.current_pstate);
 480        return mul_fp(core_busy, div_fp(max_pstate, current_pstate));
 481}
 482
 483static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
 484{
 485        int32_t busy_scaled;
 486        struct _pid *pid;
 487        signed int ctl = 0;
 488        int steps;
 489
 490        pid = &cpu->pid;
 491        busy_scaled = intel_pstate_get_scaled_busy(cpu);
 492
 493        ctl = pid_calc(pid, busy_scaled);
 494
 495        steps = abs(ctl);
 496        if (ctl < 0)
 497                intel_pstate_pstate_increase(cpu, steps);
 498        else
 499                intel_pstate_pstate_decrease(cpu, steps);
 500}
 501
 502static void intel_pstate_timer_func(unsigned long __data)
 503{
 504        struct cpudata *cpu = (struct cpudata *) __data;
 505
 506        intel_pstate_sample(cpu);
 507        intel_pstate_adjust_busy_pstate(cpu);
 508
 509        if (cpu->pstate.current_pstate == cpu->pstate.min_pstate) {
 510                cpu->min_pstate_count++;
 511                if (!(cpu->min_pstate_count % 5)) {
 512                        intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 513                }
 514        } else
 515                cpu->min_pstate_count = 0;
 516
 517        intel_pstate_set_sample_time(cpu);
 518}
 519
 520#define ICPU(model, policy) \
 521        { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&policy }
 522
 523static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
 524        ICPU(0x2a, default_policy),
 525        ICPU(0x2d, default_policy),
 526        ICPU(0x3a, default_policy),
 527        ICPU(0x3c, default_policy),
 528        ICPU(0x3e, default_policy),
 529        ICPU(0x3f, default_policy),
 530        ICPU(0x45, default_policy),
 531        ICPU(0x46, default_policy),
 532        {}
 533};
 534MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
 535
 536static int intel_pstate_init_cpu(unsigned int cpunum)
 537{
 538
 539        const struct x86_cpu_id *id;
 540        struct cpudata *cpu;
 541
 542        id = x86_match_cpu(intel_pstate_cpu_ids);
 543        if (!id)
 544                return -ENODEV;
 545
 546        all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
 547        if (!all_cpu_data[cpunum])
 548                return -ENOMEM;
 549
 550        cpu = all_cpu_data[cpunum];
 551
 552        intel_pstate_get_cpu_pstates(cpu);
 553
 554        cpu->cpu = cpunum;
 555        cpu->pstate_policy =
 556                (struct pstate_adjust_policy *)id->driver_data;
 557        init_timer_deferrable(&cpu->timer);
 558        cpu->timer.function = intel_pstate_timer_func;
 559        cpu->timer.data =
 560                (unsigned long)cpu;
 561        cpu->timer.expires = jiffies + HZ/100;
 562        intel_pstate_busy_pid_reset(cpu);
 563        intel_pstate_sample(cpu);
 564        intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 565
 566        add_timer_on(&cpu->timer, cpunum);
 567
 568        pr_info("Intel pstate controlling: cpu %d\n", cpunum);
 569
 570        return 0;
 571}
 572
 573static unsigned int intel_pstate_get(unsigned int cpu_num)
 574{
 575        struct sample *sample;
 576        struct cpudata *cpu;
 577
 578        cpu = all_cpu_data[cpu_num];
 579        if (!cpu)
 580                return 0;
 581        sample = &cpu->samples[cpu->sample_ptr];
 582        return sample->freq;
 583}
 584
 585static int intel_pstate_set_policy(struct cpufreq_policy *policy)
 586{
 587        struct cpudata *cpu;
 588
 589        cpu = all_cpu_data[policy->cpu];
 590
 591        if (!policy->cpuinfo.max_freq)
 592                return -ENODEV;
 593
 594        if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
 595                limits.min_perf_pct = 100;
 596                limits.min_perf = int_tofp(1);
 597                limits.max_perf_pct = 100;
 598                limits.max_perf = int_tofp(1);
 599                limits.no_turbo = 0;
 600                return 0;
 601        }
 602        limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
 603        limits.min_perf_pct = clamp_t(int, limits.min_perf_pct, 0 , 100);
 604        limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
 605
 606        limits.max_policy_pct = policy->max * 100 / policy->cpuinfo.max_freq;
 607        limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100);
 608        limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
 609        limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
 610
 611        return 0;
 612}
 613
 614static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
 615{
 616        cpufreq_verify_within_limits(policy,
 617                                policy->cpuinfo.min_freq,
 618                                policy->cpuinfo.max_freq);
 619
 620        if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
 621                (policy->policy != CPUFREQ_POLICY_PERFORMANCE))
 622                return -EINVAL;
 623
 624        return 0;
 625}
 626
 627static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
 628{
 629        int cpu = policy->cpu;
 630
 631        del_timer(&all_cpu_data[cpu]->timer);
 632        kfree(all_cpu_data[cpu]);
 633        all_cpu_data[cpu] = NULL;
 634        return 0;
 635}
 636
 637static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
 638{
 639        struct cpudata *cpu;
 640        int rc;
 641
 642        rc = intel_pstate_init_cpu(policy->cpu);
 643        if (rc)
 644                return rc;
 645
 646        cpu = all_cpu_data[policy->cpu];
 647
 648        if (!limits.no_turbo &&
 649                limits.min_perf_pct == 100 && limits.max_perf_pct == 100)
 650                policy->policy = CPUFREQ_POLICY_PERFORMANCE;
 651        else
 652                policy->policy = CPUFREQ_POLICY_POWERSAVE;
 653
 654        policy->min = cpu->pstate.min_pstate * 100000;
 655        policy->max = cpu->pstate.turbo_pstate * 100000;
 656
 657        /* cpuinfo and default policy values */
 658        policy->cpuinfo.min_freq = cpu->pstate.min_pstate * 100000;
 659        policy->cpuinfo.max_freq = cpu->pstate.turbo_pstate * 100000;
 660        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 661        cpumask_set_cpu(policy->cpu, policy->cpus);
 662
 663        return 0;
 664}
 665
 666static struct cpufreq_driver intel_pstate_driver = {
 667        .flags          = CPUFREQ_CONST_LOOPS,
 668        .verify         = intel_pstate_verify_policy,
 669        .setpolicy      = intel_pstate_set_policy,
 670        .get            = intel_pstate_get,
 671        .init           = intel_pstate_cpu_init,
 672        .exit           = intel_pstate_cpu_exit,
 673        .name           = "intel_pstate",
 674};
 675
 676static int __initdata no_load;
 677
 678static int intel_pstate_msrs_not_valid(void)
 679{
 680        /* Check that all the msr's we are using are valid. */
 681        u64 aperf, mperf, tmp;
 682
 683        rdmsrl(MSR_IA32_APERF, aperf);
 684        rdmsrl(MSR_IA32_MPERF, mperf);
 685
 686        if (!intel_pstate_min_pstate() ||
 687                !intel_pstate_max_pstate() ||
 688                !intel_pstate_turbo_pstate())
 689                return -ENODEV;
 690
 691        rdmsrl(MSR_IA32_APERF, tmp);
 692        if (!(tmp - aperf))
 693                return -ENODEV;
 694
 695        rdmsrl(MSR_IA32_MPERF, tmp);
 696        if (!(tmp - mperf))
 697                return -ENODEV;
 698
 699        return 0;
 700}
 701static int __init intel_pstate_init(void)
 702{
 703        int cpu, rc = 0;
 704        const struct x86_cpu_id *id;
 705
 706        if (no_load)
 707                return -ENODEV;
 708
 709        id = x86_match_cpu(intel_pstate_cpu_ids);
 710        if (!id)
 711                return -ENODEV;
 712
 713        if (intel_pstate_msrs_not_valid())
 714                return -ENODEV;
 715
 716        pr_info("Intel P-state driver initializing.\n");
 717
 718        all_cpu_data = vzalloc(sizeof(void *) * num_possible_cpus());
 719        if (!all_cpu_data)
 720                return -ENOMEM;
 721
 722        rc = cpufreq_register_driver(&intel_pstate_driver);
 723        if (rc)
 724                goto out;
 725
 726        intel_pstate_debug_expose_params();
 727        intel_pstate_sysfs_expose_params();
 728        return rc;
 729out:
 730        get_online_cpus();
 731        for_each_online_cpu(cpu) {
 732                if (all_cpu_data[cpu]) {
 733                        del_timer_sync(&all_cpu_data[cpu]->timer);
 734                        kfree(all_cpu_data[cpu]);
 735                }
 736        }
 737
 738        put_online_cpus();
 739        vfree(all_cpu_data);
 740        return -ENODEV;
 741}
 742device_initcall(intel_pstate_init);
 743
 744static int __init intel_pstate_setup(char *str)
 745{
 746        if (!str)
 747                return -EINVAL;
 748
 749        if (!strcmp(str, "disable"))
 750                no_load = 1;
 751        return 0;
 752}
 753early_param("intel_pstate", intel_pstate_setup);
 754
 755MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@intel.com>");
 756MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
 757MODULE_LICENSE("GPL");
 758
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