Merge tag 'sound-fix-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...

[mirror_ubuntu-artful-kernel.git] / drivers / cpufreq / intel_pstate.c

/*
 * intel_pstate.c: Native P state management for Intel processors
 *
 * (C) Copyright 2012 Intel Corporation
 * Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/ktime.h>
#include <linux/hrtimer.h>
#include <linux/tick.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/acpi.h>
#include <linux/vmalloc.h>
#include <trace/events/power.h>

#include <asm/div64.h>
#include <asm/msr.h>
#include <asm/cpu_device_id.h>
#include <asm/cpufeature.h>
#include <asm/intel-family.h>

#define ATOM_RATIOS             0x66a
#define ATOM_VIDS               0x66b
#define ATOM_TURBO_RATIOS       0x66c
#define ATOM_TURBO_VIDS         0x66d

#ifdef CONFIG_ACPI
#include <acpi/processor.h>
#endif

#define FRAC_BITS 8
#define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
#define fp_toint(X) ((X) >> FRAC_BITS)

#define EXT_BITS 6
#define EXT_FRAC_BITS (EXT_BITS + FRAC_BITS)

static inline int32_t mul_fp(int32_t x, int32_t y)
{
        return ((int64_t)x * (int64_t)y) >> FRAC_BITS;
}

static inline int32_t div_fp(s64 x, s64 y)
{
        return div64_s64((int64_t)x << FRAC_BITS, y);
}

static inline int ceiling_fp(int32_t x)
{
        int mask, ret;

        ret = fp_toint(x);
        mask = (1 << FRAC_BITS) - 1;
        if (x & mask)
                ret += 1;
        return ret;
}

static inline u64 mul_ext_fp(u64 x, u64 y)
{
        return (x * y) >> EXT_FRAC_BITS;
}

static inline u64 div_ext_fp(u64 x, u64 y)
{
        return div64_u64(x << EXT_FRAC_BITS, y);
}

/**
 * struct sample -      Store performance sample
 * @core_avg_perf:      Ratio of APERF/MPERF which is the actual average
 *                      performance during last sample period
 * @busy_scaled:        Scaled busy value which is used to calculate next
 *                      P state. This can be different than core_avg_perf
 *                      to account for cpu idle period
 * @aperf:              Difference of actual performance frequency clock count
 *                      read from APERF MSR between last and current sample
 * @mperf:              Difference of maximum performance frequency clock count
 *                      read from MPERF MSR between last and current sample
 * @tsc:                Difference of time stamp counter between last and
 *                      current sample
 * @time:               Current time from scheduler
 *
 * This structure is used in the cpudata structure to store performance sample
 * data for choosing next P State.
 */
struct sample {
        int32_t core_avg_perf;
        int32_t busy_scaled;
        u64 aperf;
        u64 mperf;
        u64 tsc;
        u64 time;
};

/**
 * struct pstate_data - Store P state data
 * @current_pstate:     Current requested P state
 * @min_pstate:         Min P state possible for this platform
 * @max_pstate:         Max P state possible for this platform
 * @max_pstate_physical:This is physical Max P state for a processor
 *                      This can be higher than the max_pstate which can
 *                      be limited by platform thermal design power limits
 * @scaling:            Scaling factor to  convert frequency to cpufreq
 *                      frequency units
 * @turbo_pstate:       Max Turbo P state possible for this platform
 *
 * Stores the per cpu model P state limits and current P state.
 */
struct pstate_data {
        int     current_pstate;
        int     min_pstate;
        int     max_pstate;
        int     max_pstate_physical;
        int     scaling;
        int     turbo_pstate;
};

/**
 * struct vid_data -    Stores voltage information data
 * @min:                VID data for this platform corresponding to
 *                      the lowest P state
 * @max:                VID data corresponding to the highest P State.
 * @turbo:              VID data for turbo P state
 * @ratio:              Ratio of (vid max - vid min) /
 *                      (max P state - Min P State)
 *
 * Stores the voltage data for DVFS (Dynamic Voltage and Frequency Scaling)
 * This data is used in Atom platforms, where in addition to target P state,
 * the voltage data needs to be specified to select next P State.
 */
struct vid_data {
        int min;
        int max;
        int turbo;
        int32_t ratio;
};

/**
 * struct _pid -        Stores PID data
 * @setpoint:           Target set point for busyness or performance
 * @integral:           Storage for accumulated error values
 * @p_gain:             PID proportional gain
 * @i_gain:             PID integral gain
 * @d_gain:             PID derivative gain
 * @deadband:           PID deadband
 * @last_err:           Last error storage for integral part of PID calculation
 *
 * Stores PID coefficients and last error for PID controller.
 */
struct _pid {
        int setpoint;
        int32_t integral;
        int32_t p_gain;
        int32_t i_gain;
        int32_t d_gain;
        int deadband;
        int32_t last_err;
};

/**
 * struct cpudata -     Per CPU instance data storage
 * @cpu:                CPU number for this instance data
 * @update_util:        CPUFreq utility callback information
 * @update_util_set:    CPUFreq utility callback is set
 * @iowait_boost:       iowait-related boost fraction
 * @last_update:        Time of the last update.
 * @pstate:             Stores P state limits for this CPU
 * @vid:                Stores VID limits for this CPU
 * @pid:                Stores PID parameters for this CPU
 * @last_sample_time:   Last Sample time
 * @prev_aperf:         Last APERF value read from APERF MSR
 * @prev_mperf:         Last MPERF value read from MPERF MSR
 * @prev_tsc:           Last timestamp counter (TSC) value
 * @prev_cummulative_iowait: IO Wait time difference from last and
 *                      current sample
 * @sample:             Storage for storing last Sample data
 * @acpi_perf_data:     Stores ACPI perf information read from _PSS
 * @valid_pss_table:    Set to true for valid ACPI _PSS entries found
 *
 * This structure stores per CPU instance data for all CPUs.
 */
struct cpudata {
        int cpu;

        struct update_util_data update_util;
        bool   update_util_set;

        struct pstate_data pstate;
        struct vid_data vid;
        struct _pid pid;

        u64     last_update;
        u64     last_sample_time;
        u64     prev_aperf;
        u64     prev_mperf;
        u64     prev_tsc;
        u64     prev_cummulative_iowait;
        struct sample sample;
#ifdef CONFIG_ACPI
        struct acpi_processor_performance acpi_perf_data;
        bool valid_pss_table;
#endif
        unsigned int iowait_boost;
};

static struct cpudata **all_cpu_data;

/**
 * struct pstate_adjust_policy - Stores static PID configuration data
 * @sample_rate_ms:     PID calculation sample rate in ms
 * @sample_rate_ns:     Sample rate calculation in ns
 * @deadband:           PID deadband
 * @setpoint:           PID Setpoint
 * @p_gain_pct:         PID proportional gain
 * @i_gain_pct:         PID integral gain
 * @d_gain_pct:         PID derivative gain
 * @boost_iowait:       Whether or not to use iowait boosting.
 *
 * Stores per CPU model static PID configuration data.
 */
struct pstate_adjust_policy {
        int sample_rate_ms;
        s64 sample_rate_ns;
        int deadband;
        int setpoint;
        int p_gain_pct;
        int d_gain_pct;
        int i_gain_pct;
        bool boost_iowait;
};

/**
 * struct pstate_funcs - Per CPU model specific callbacks
 * @get_max:            Callback to get maximum non turbo effective P state
 * @get_max_physical:   Callback to get maximum non turbo physical P state
 * @get_min:            Callback to get minimum P state
 * @get_turbo:          Callback to get turbo P state
 * @get_scaling:        Callback to get frequency scaling factor
 * @get_val:            Callback to convert P state to actual MSR write value
 * @get_vid:            Callback to get VID data for Atom platforms
 * @get_target_pstate:  Callback to a function to calculate next P state to use
 *
 * Core and Atom CPU models have different way to get P State limits. This
 * structure is used to store those callbacks.
 */
struct pstate_funcs {
        int (*get_max)(void);
        int (*get_max_physical)(void);
        int (*get_min)(void);
        int (*get_turbo)(void);
        int (*get_scaling)(void);
        u64 (*get_val)(struct cpudata*, int pstate);
        void (*get_vid)(struct cpudata *);
        int32_t (*get_target_pstate)(struct cpudata *);
};

/**
 * struct cpu_defaults- Per CPU model default config data
 * @pid_policy: PID config data
 * @funcs:              Callback function data
 */
struct cpu_defaults {
        struct pstate_adjust_policy pid_policy;
        struct pstate_funcs funcs;
};

static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu);
static inline int32_t get_target_pstate_use_cpu_load(struct cpudata *cpu);

static struct pstate_adjust_policy pid_params __read_mostly;
static struct pstate_funcs pstate_funcs __read_mostly;
static int hwp_active __read_mostly;

#ifdef CONFIG_ACPI
static bool acpi_ppc;
#endif

/**
 * struct perf_limits - Store user and policy limits
 * @no_turbo:           User requested turbo state from intel_pstate sysfs
 * @turbo_disabled:     Platform turbo status either from msr
 *                      MSR_IA32_MISC_ENABLE or when maximum available pstate
 *                      matches the maximum turbo pstate
 * @max_perf_pct:       Effective maximum performance limit in percentage, this
 *                      is minimum of either limits enforced by cpufreq policy
 *                      or limits from user set limits via intel_pstate sysfs
 * @min_perf_pct:       Effective minimum performance limit in percentage, this
 *                      is maximum of either limits enforced by cpufreq policy
 *                      or limits from user set limits via intel_pstate sysfs
 * @max_perf:           This is a scaled value between 0 to 255 for max_perf_pct
 *                      This value is used to limit max pstate
 * @min_perf:           This is a scaled value between 0 to 255 for min_perf_pct
 *                      This value is used to limit min pstate
 * @max_policy_pct:     The maximum performance in percentage enforced by
 *                      cpufreq setpolicy interface
 * @max_sysfs_pct:      The maximum performance in percentage enforced by
 *                      intel pstate sysfs interface
 * @min_policy_pct:     The minimum performance in percentage enforced by
 *                      cpufreq setpolicy interface
 * @min_sysfs_pct:      The minimum performance in percentage enforced by
 *                      intel pstate sysfs interface
 *
 * Storage for user and policy defined limits.
 */
struct perf_limits {
        int no_turbo;
        int turbo_disabled;
        int max_perf_pct;
        int min_perf_pct;
        int32_t max_perf;
        int32_t min_perf;
        int max_policy_pct;
        int max_sysfs_pct;
        int min_policy_pct;
        int min_sysfs_pct;
};

static struct perf_limits performance_limits = {
        .no_turbo = 0,
        .turbo_disabled = 0,
        .max_perf_pct = 100,
        .max_perf = int_tofp(1),
        .min_perf_pct = 100,
        .min_perf = int_tofp(1),
        .max_policy_pct = 100,
        .max_sysfs_pct = 100,
        .min_policy_pct = 0,
        .min_sysfs_pct = 0,
};

static struct perf_limits powersave_limits = {
        .no_turbo = 0,
        .turbo_disabled = 0,
        .max_perf_pct = 100,
        .max_perf = int_tofp(1),
        .min_perf_pct = 0,
        .min_perf = 0,
        .max_policy_pct = 100,
        .max_sysfs_pct = 100,
        .min_policy_pct = 0,
        .min_sysfs_pct = 0,
};

#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
static struct perf_limits *limits = &performance_limits;
#else
static struct perf_limits *limits = &powersave_limits;
#endif

#ifdef CONFIG_ACPI

static bool intel_pstate_get_ppc_enable_status(void)
{
        if (acpi_gbl_FADT.preferred_profile == PM_ENTERPRISE_SERVER ||
            acpi_gbl_FADT.preferred_profile == PM_PERFORMANCE_SERVER)
                return true;

        return acpi_ppc;
}

static void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
{
        struct cpudata *cpu;
        int ret;
        int i;

        if (hwp_active)
                return;

        if (!intel_pstate_get_ppc_enable_status())
                return;

        cpu = all_cpu_data[policy->cpu];

        ret = acpi_processor_register_performance(&cpu->acpi_perf_data,
                                                  policy->cpu);
        if (ret)
                return;

        /*
         * Check if the control value in _PSS is for PERF_CTL MSR, which should
         * guarantee that the states returned by it map to the states in our
         * list directly.
         */
        if (cpu->acpi_perf_data.control_register.space_id !=
                                                ACPI_ADR_SPACE_FIXED_HARDWARE)
                goto err;

        /*
         * If there is only one entry _PSS, simply ignore _PSS and continue as
         * usual without taking _PSS into account
         */
        if (cpu->acpi_perf_data.state_count < 2)
                goto err;

        pr_debug("CPU%u - ACPI _PSS perf data\n", policy->cpu);
        for (i = 0; i < cpu->acpi_perf_data.state_count; i++) {
                pr_debug("     %cP%d: %u MHz, %u mW, 0x%x\n",
                         (i == cpu->acpi_perf_data.state ? '*' : ' '), i,
                         (u32) cpu->acpi_perf_data.states[i].core_frequency,
                         (u32) cpu->acpi_perf_data.states[i].power,
                         (u32) cpu->acpi_perf_data.states[i].control);
        }

        /*
         * The _PSS table doesn't contain whole turbo frequency range.
         * This just contains +1 MHZ above the max non turbo frequency,
         * with control value corresponding to max turbo ratio. But
         * when cpufreq set policy is called, it will call with this
         * max frequency, which will cause a reduced performance as
         * this driver uses real max turbo frequency as the max
         * frequency. So correct this frequency in _PSS table to
         * correct max turbo frequency based on the turbo state.
         * Also need to convert to MHz as _PSS freq is in MHz.
         */
        if (!limits->turbo_disabled)
                cpu->acpi_perf_data.states[0].core_frequency =
                                        policy->cpuinfo.max_freq / 1000;
        cpu->valid_pss_table = true;
        pr_debug("_PPC limits will be enforced\n");

        return;

 err:
        cpu->valid_pss_table = false;
        acpi_processor_unregister_performance(policy->cpu);
}

static void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
{
        struct cpudata *cpu;

        cpu = all_cpu_data[policy->cpu];
        if (!cpu->valid_pss_table)
                return;

        acpi_processor_unregister_performance(policy->cpu);
}

#else
static void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
{
}

static void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
{
}
#endif

static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
                             int deadband, int integral) {
        pid->setpoint = int_tofp(setpoint);
        pid->deadband  = int_tofp(deadband);
        pid->integral  = int_tofp(integral);
        pid->last_err  = int_tofp(setpoint) - int_tofp(busy);
}

static inline void pid_p_gain_set(struct _pid *pid, int percent)
{
        pid->p_gain = div_fp(percent, 100);
}

static inline void pid_i_gain_set(struct _pid *pid, int percent)
{
        pid->i_gain = div_fp(percent, 100);
}

static inline void pid_d_gain_set(struct _pid *pid, int percent)
{
        pid->d_gain = div_fp(percent, 100);
}

static signed int pid_calc(struct _pid *pid, int32_t busy)
{
        signed int result;
        int32_t pterm, dterm, fp_error;
        int32_t integral_limit;

        fp_error = pid->setpoint - busy;

        if (abs(fp_error) <= pid->deadband)
                return 0;

        pterm = mul_fp(pid->p_gain, fp_error);

        pid->integral += fp_error;

        /*
         * We limit the integral here so that it will never
         * get higher than 30.  This prevents it from becoming
         * too large an input over long periods of time and allows
         * it to get factored out sooner.
         *
         * The value of 30 was chosen through experimentation.
         */
        integral_limit = int_tofp(30);
        if (pid->integral > integral_limit)
                pid->integral = integral_limit;
        if (pid->integral < -integral_limit)
                pid->integral = -integral_limit;

        dterm = mul_fp(pid->d_gain, fp_error - pid->last_err);
        pid->last_err = fp_error;

        result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
        result = result + (1 << (FRAC_BITS-1));
        return (signed int)fp_toint(result);
}

static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
{
        pid_p_gain_set(&cpu->pid, pid_params.p_gain_pct);
        pid_d_gain_set(&cpu->pid, pid_params.d_gain_pct);
        pid_i_gain_set(&cpu->pid, pid_params.i_gain_pct);

        pid_reset(&cpu->pid, pid_params.setpoint, 100, pid_params.deadband, 0);
}

static inline void intel_pstate_reset_all_pid(void)
{
        unsigned int cpu;

        for_each_online_cpu(cpu) {
                if (all_cpu_data[cpu])
                        intel_pstate_busy_pid_reset(all_cpu_data[cpu]);
        }
}

static inline void update_turbo_state(void)
{
        u64 misc_en;
        struct cpudata *cpu;

        cpu = all_cpu_data[0];
        rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
        limits->turbo_disabled =
                (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE ||
                 cpu->pstate.max_pstate == cpu->pstate.turbo_pstate);
}

static void intel_pstate_hwp_set(const struct cpumask *cpumask)
{
        int min, hw_min, max, hw_max, cpu, range, adj_range;
        u64 value, cap;

        for_each_cpu(cpu, cpumask) {
                rdmsrl_on_cpu(cpu, MSR_HWP_CAPABILITIES, &cap);
                hw_min = HWP_LOWEST_PERF(cap);
                hw_max = HWP_HIGHEST_PERF(cap);
                range = hw_max - hw_min;

                rdmsrl_on_cpu(cpu, MSR_HWP_REQUEST, &value);
                adj_range = limits->min_perf_pct * range / 100;
                min = hw_min + adj_range;
                value &= ~HWP_MIN_PERF(~0L);
                value |= HWP_MIN_PERF(min);

                adj_range = limits->max_perf_pct * range / 100;
                max = hw_min + adj_range;
                if (limits->no_turbo) {
                        hw_max = HWP_GUARANTEED_PERF(cap);
                        if (hw_max < max)
                                max = hw_max;
                }

                value &= ~HWP_MAX_PERF(~0L);
                value |= HWP_MAX_PERF(max);
                wrmsrl_on_cpu(cpu, MSR_HWP_REQUEST, value);
        }
}

static int intel_pstate_hwp_set_policy(struct cpufreq_policy *policy)
{
        if (hwp_active)
                intel_pstate_hwp_set(policy->cpus);

        return 0;
}

static void intel_pstate_hwp_set_online_cpus(void)
{
        get_online_cpus();
        intel_pstate_hwp_set(cpu_online_mask);
        put_online_cpus();
}

/************************** debugfs begin ************************/
static int pid_param_set(void *data, u64 val)
{
        *(u32 *)data = val;
        intel_pstate_reset_all_pid();
        return 0;
}

static int pid_param_get(void *data, u64 *val)
{
        *val = *(u32 *)data;
        return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get, pid_param_set, "%llu\n");

struct pid_param {
        char *name;
        void *value;
};

static struct pid_param pid_files[] = {
        {"sample_rate_ms", &pid_params.sample_rate_ms},
        {"d_gain_pct", &pid_params.d_gain_pct},
        {"i_gain_pct", &pid_params.i_gain_pct},
        {"deadband", &pid_params.deadband},
        {"setpoint", &pid_params.setpoint},
        {"p_gain_pct", &pid_params.p_gain_pct},
        {NULL, NULL}
};

static void __init intel_pstate_debug_expose_params(void)
{
        struct dentry *debugfs_parent;
        int i = 0;

        if (hwp_active)
                return;
        debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
        if (IS_ERR_OR_NULL(debugfs_parent))
                return;
        while (pid_files[i].name) {
                debugfs_create_file(pid_files[i].name, 0660,
                                    debugfs_parent, pid_files[i].value,
                                    &fops_pid_param);
                i++;
        }
}

/************************** debugfs end ************************/

/************************** sysfs begin ************************/
#define show_one(file_name, object)                                     \
        static ssize_t show_##file_name                                 \
        (struct kobject *kobj, struct attribute *attr, char *buf)       \
        {                                                               \
                return sprintf(buf, "%u\n", limits->object);            \
        }

static ssize_t show_turbo_pct(struct kobject *kobj,
                                struct attribute *attr, char *buf)
{
        struct cpudata *cpu;
        int total, no_turbo, turbo_pct;
        uint32_t turbo_fp;

        cpu = all_cpu_data[0];

        total = cpu->pstate.turbo_pstate - cpu->pstate.min_pstate + 1;
        no_turbo = cpu->pstate.max_pstate - cpu->pstate.min_pstate + 1;
        turbo_fp = div_fp(no_turbo, total);
        turbo_pct = 100 - fp_toint(mul_fp(turbo_fp, int_tofp(100)));
        return sprintf(buf, "%u\n", turbo_pct);
}

static ssize_t show_num_pstates(struct kobject *kobj,
                                struct attribute *attr, char *buf)
{
        struct cpudata *cpu;
        int total;

        cpu = all_cpu_data[0];
        total = cpu->pstate.turbo_pstate - cpu->pstate.min_pstate + 1;
        return sprintf(buf, "%u\n", total);
}

static ssize_t show_no_turbo(struct kobject *kobj,
                             struct attribute *attr, char *buf)
{
        ssize_t ret;

        update_turbo_state();
        if (limits->turbo_disabled)
                ret = sprintf(buf, "%u\n", limits->turbo_disabled);
        else
                ret = sprintf(buf, "%u\n", limits->no_turbo);

        return ret;
}

static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
                              const char *buf, size_t count)
{
        unsigned int input;
        int ret;

        ret = sscanf(buf, "%u", &input);
        if (ret != 1)
                return -EINVAL;

        update_turbo_state();
        if (limits->turbo_disabled) {
                pr_warn("Turbo disabled by BIOS or unavailable on processor\n");
                return -EPERM;
        }

        limits->no_turbo = clamp_t(int, input, 0, 1);

        if (hwp_active)
                intel_pstate_hwp_set_online_cpus();

        return count;
}

static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b,
                                  const char *buf, size_t count)
{
        unsigned int input;
        int ret;

        ret = sscanf(buf, "%u", &input);
        if (ret != 1)
                return -EINVAL;

        limits->max_sysfs_pct = clamp_t(int, input, 0 , 100);
        limits->max_perf_pct = min(limits->max_policy_pct,
                                   limits->max_sysfs_pct);
        limits->max_perf_pct = max(limits->min_policy_pct,
                                   limits->max_perf_pct);
        limits->max_perf_pct = max(limits->min_perf_pct,
                                   limits->max_perf_pct);
        limits->max_perf = div_fp(limits->max_perf_pct, 100);

        if (hwp_active)
                intel_pstate_hwp_set_online_cpus();
        return count;
}

static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
                                  const char *buf, size_t count)
{
        unsigned int input;
        int ret;

        ret = sscanf(buf, "%u", &input);
        if (ret != 1)
                return -EINVAL;

        limits->min_sysfs_pct = clamp_t(int, input, 0 , 100);
        limits->min_perf_pct = max(limits->min_policy_pct,
                                   limits->min_sysfs_pct);
        limits->min_perf_pct = min(limits->max_policy_pct,
                                   limits->min_perf_pct);
        limits->min_perf_pct = min(limits->max_perf_pct,
                                   limits->min_perf_pct);
        limits->min_perf = div_fp(limits->min_perf_pct, 100);

        if (hwp_active)
                intel_pstate_hwp_set_online_cpus();
        return count;
}

show_one(max_perf_pct, max_perf_pct);
show_one(min_perf_pct, min_perf_pct);

define_one_global_rw(no_turbo);
define_one_global_rw(max_perf_pct);
define_one_global_rw(min_perf_pct);
define_one_global_ro(turbo_pct);
define_one_global_ro(num_pstates);

static struct attribute *intel_pstate_attributes[] = {
        &no_turbo.attr,
        &max_perf_pct.attr,
        &min_perf_pct.attr,
        &turbo_pct.attr,
        &num_pstates.attr,
        NULL
};

static struct attribute_group intel_pstate_attr_group = {
        .attrs = intel_pstate_attributes,
};

static void __init intel_pstate_sysfs_expose_params(void)
{
        struct kobject *intel_pstate_kobject;
        int rc;

        intel_pstate_kobject = kobject_create_and_add("intel_pstate",
                                                &cpu_subsys.dev_root->kobj);
        BUG_ON(!intel_pstate_kobject);
        rc = sysfs_create_group(intel_pstate_kobject, &intel_pstate_attr_group);
        BUG_ON(rc);
}
/************************** sysfs end ************************/

static void intel_pstate_hwp_enable(struct cpudata *cpudata)
{
        /* First disable HWP notification interrupt as we don't process them */
        if (static_cpu_has(X86_FEATURE_HWP_NOTIFY))
                wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_INTERRUPT, 0x00);

        wrmsrl_on_cpu(cpudata->cpu, MSR_PM_ENABLE, 0x1);
}

static int atom_get_min_pstate(void)
{
        u64 value;

        rdmsrl(ATOM_RATIOS, value);
        return (value >> 8) & 0x7F;
}

static int atom_get_max_pstate(void)
{
        u64 value;

        rdmsrl(ATOM_RATIOS, value);
        return (value >> 16) & 0x7F;
}

static int atom_get_turbo_pstate(void)
{
        u64 value;

        rdmsrl(ATOM_TURBO_RATIOS, value);
        return value & 0x7F;
}

static u64 atom_get_val(struct cpudata *cpudata, int pstate)
{
        u64 val;
        int32_t vid_fp;
        u32 vid;

        val = (u64)pstate << 8;
        if (limits->no_turbo && !limits->turbo_disabled)
                val |= (u64)1 << 32;

        vid_fp = cpudata->vid.min + mul_fp(
                int_tofp(pstate - cpudata->pstate.min_pstate),
                cpudata->vid.ratio);

        vid_fp = clamp_t(int32_t, vid_fp, cpudata->vid.min, cpudata->vid.max);
        vid = ceiling_fp(vid_fp);

        if (pstate > cpudata->pstate.max_pstate)
                vid = cpudata->vid.turbo;

        return val | vid;
}

static int silvermont_get_scaling(void)
{
        u64 value;
        int i;
        /* Defined in Table 35-6 from SDM (Sept 2015) */
        static int silvermont_freq_table[] = {
                83300, 100000, 133300, 116700, 80000};

        rdmsrl(MSR_FSB_FREQ, value);
        i = value & 0x7;
        WARN_ON(i > 4);

        return silvermont_freq_table[i];
}

static int airmont_get_scaling(void)
{
        u64 value;
        int i;
        /* Defined in Table 35-10 from SDM (Sept 2015) */
        static int airmont_freq_table[] = {
                83300, 100000, 133300, 116700, 80000,
                93300, 90000, 88900, 87500};

        rdmsrl(MSR_FSB_FREQ, value);
        i = value & 0xF;
        WARN_ON(i > 8);

        return airmont_freq_table[i];
}

static void atom_get_vid(struct cpudata *cpudata)
{
        u64 value;

        rdmsrl(ATOM_VIDS, value);
        cpudata->vid.min = int_tofp((value >> 8) & 0x7f);
        cpudata->vid.max = int_tofp((value >> 16) & 0x7f);
        cpudata->vid.ratio = div_fp(
                cpudata->vid.max - cpudata->vid.min,
                int_tofp(cpudata->pstate.max_pstate -
                        cpudata->pstate.min_pstate));

        rdmsrl(ATOM_TURBO_VIDS, value);
        cpudata->vid.turbo = value & 0x7f;
}

static int core_get_min_pstate(void)
{
        u64 value;

        rdmsrl(MSR_PLATFORM_INFO, value);
        return (value >> 40) & 0xFF;
}

static int core_get_max_pstate_physical(void)
{
        u64 value;

        rdmsrl(MSR_PLATFORM_INFO, value);
        return (value >> 8) & 0xFF;
}

static int core_get_max_pstate(void)
{
        u64 tar;
        u64 plat_info;
        int max_pstate;
        int err;

        rdmsrl(MSR_PLATFORM_INFO, plat_info);
        max_pstate = (plat_info >> 8) & 0xFF;

        err = rdmsrl_safe(MSR_TURBO_ACTIVATION_RATIO, &tar);
        if (!err) {
                /* Do some sanity checking for safety */
                if (plat_info & 0x600000000) {
                        u64 tdp_ctrl;
                        u64 tdp_ratio;
                        int tdp_msr;

                        err = rdmsrl_safe(MSR_CONFIG_TDP_CONTROL, &tdp_ctrl);
                        if (err)
                                goto skip_tar;

                        tdp_msr = MSR_CONFIG_TDP_NOMINAL + (tdp_ctrl & 0x3);
                        err = rdmsrl_safe(tdp_msr, &tdp_ratio);
                        if (err)
                                goto skip_tar;

                        /* For level 1 and 2, bits[23:16] contain the ratio */
                        if (tdp_ctrl)
                                tdp_ratio >>= 16;

                        tdp_ratio &= 0xff; /* ratios are only 8 bits long */
                        if (tdp_ratio - 1 == tar) {
                                max_pstate = tar;
                                pr_debug("max_pstate=TAC %x\n", max_pstate);
                        } else {
                                goto skip_tar;
                        }
                }
        }

skip_tar:
        return max_pstate;
}

static int core_get_turbo_pstate(void)
{
        u64 value;
        int nont, ret;

        rdmsrl(MSR_TURBO_RATIO_LIMIT, value);
        nont = core_get_max_pstate();
        ret = (value) & 255;
        if (ret <= nont)
                ret = nont;
        return ret;
}

static inline int core_get_scaling(void)
{
        return 100000;
}

static u64 core_get_val(struct cpudata *cpudata, int pstate)
{
        u64 val;

        val = (u64)pstate << 8;
        if (limits->no_turbo && !limits->turbo_disabled)
                val |= (u64)1 << 32;

        return val;
}

static int knl_get_turbo_pstate(void)
{
        u64 value;
        int nont, ret;

        rdmsrl(MSR_TURBO_RATIO_LIMIT, value);
        nont = core_get_max_pstate();
        ret = (((value) >> 8) & 0xFF);
        if (ret <= nont)
                ret = nont;
        return ret;
}

static struct cpu_defaults core_params = {
        .pid_policy = {
                .sample_rate_ms = 10,
                .deadband = 0,
                .setpoint = 97,
                .p_gain_pct = 20,
                .d_gain_pct = 0,
                .i_gain_pct = 0,
        },
        .funcs = {
                .get_max = core_get_max_pstate,
                .get_max_physical = core_get_max_pstate_physical,
                .get_min = core_get_min_pstate,
                .get_turbo = core_get_turbo_pstate,
                .get_scaling = core_get_scaling,
                .get_val = core_get_val,
                .get_target_pstate = get_target_pstate_use_performance,
        },
};

static const struct cpu_defaults silvermont_params = {
        .pid_policy = {
                .sample_rate_ms = 10,
                .deadband = 0,
                .setpoint = 60,
                .p_gain_pct = 14,
                .d_gain_pct = 0,
                .i_gain_pct = 4,
                .boost_iowait = true,
        },
        .funcs = {
                .get_max = atom_get_max_pstate,
                .get_max_physical = atom_get_max_pstate,
                .get_min = atom_get_min_pstate,
                .get_turbo = atom_get_turbo_pstate,
                .get_val = atom_get_val,
                .get_scaling = silvermont_get_scaling,
                .get_vid = atom_get_vid,
                .get_target_pstate = get_target_pstate_use_cpu_load,
        },
};

static const struct cpu_defaults airmont_params = {
        .pid_policy = {
                .sample_rate_ms = 10,
                .deadband = 0,
                .setpoint = 60,
                .p_gain_pct = 14,
                .d_gain_pct = 0,
                .i_gain_pct = 4,
                .boost_iowait = true,
        },
        .funcs = {
                .get_max = atom_get_max_pstate,
                .get_max_physical = atom_get_max_pstate,
                .get_min = atom_get_min_pstate,
                .get_turbo = atom_get_turbo_pstate,
                .get_val = atom_get_val,
                .get_scaling = airmont_get_scaling,
                .get_vid = atom_get_vid,
                .get_target_pstate = get_target_pstate_use_cpu_load,
        },
};

static const struct cpu_defaults knl_params = {
        .pid_policy = {
                .sample_rate_ms = 10,
                .deadband = 0,
                .setpoint = 97,
                .p_gain_pct = 20,
                .d_gain_pct = 0,
                .i_gain_pct = 0,
        },
        .funcs = {
                .get_max = core_get_max_pstate,
                .get_max_physical = core_get_max_pstate_physical,
                .get_min = core_get_min_pstate,
                .get_turbo = knl_get_turbo_pstate,
                .get_scaling = core_get_scaling,
                .get_val = core_get_val,
                .get_target_pstate = get_target_pstate_use_performance,
        },
};

static const struct cpu_defaults bxt_params = {
        .pid_policy = {
                .sample_rate_ms = 10,
                .deadband = 0,
                .setpoint = 60,
                .p_gain_pct = 14,
                .d_gain_pct = 0,
                .i_gain_pct = 4,
                .boost_iowait = true,
        },
        .funcs = {
                .get_max = core_get_max_pstate,
                .get_max_physical = core_get_max_pstate_physical,
                .get_min = core_get_min_pstate,
                .get_turbo = core_get_turbo_pstate,
                .get_scaling = core_get_scaling,
                .get_val = core_get_val,
                .get_target_pstate = get_target_pstate_use_cpu_load,
        },
};

static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
{
        int max_perf = cpu->pstate.turbo_pstate;
        int max_perf_adj;
        int min_perf;

        if (limits->no_turbo || limits->turbo_disabled)
                max_perf = cpu->pstate.max_pstate;

        /*
         * performance can be limited by user through sysfs, by cpufreq
         * policy, or by cpu specific default values determined through
         * experimentation.
         */
        max_perf_adj = fp_toint(max_perf * limits->max_perf);
        *max = clamp_t(int, max_perf_adj,
                        cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);

        min_perf = fp_toint(max_perf * limits->min_perf);
        *min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf);
}

static void intel_pstate_set_min_pstate(struct cpudata *cpu)
{
        int pstate = cpu->pstate.min_pstate;

        trace_cpu_frequency(pstate * cpu->pstate.scaling, cpu->cpu);
        cpu->pstate.current_pstate = pstate;
        /*
         * Generally, there is no guarantee that this code will always run on
         * the CPU being updated, so force the register update to run on the
         * right CPU.
         */
        wrmsrl_on_cpu(cpu->cpu, MSR_IA32_PERF_CTL,
                      pstate_funcs.get_val(cpu, pstate));
}

static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
{
        cpu->pstate.min_pstate = pstate_funcs.get_min();
        cpu->pstate.max_pstate = pstate_funcs.get_max();
        cpu->pstate.max_pstate_physical = pstate_funcs.get_max_physical();
        cpu->pstate.turbo_pstate = pstate_funcs.get_turbo();
        cpu->pstate.scaling = pstate_funcs.get_scaling();

        if (pstate_funcs.get_vid)
                pstate_funcs.get_vid(cpu);

        intel_pstate_set_min_pstate(cpu);
}

static inline void intel_pstate_calc_avg_perf(struct cpudata *cpu)
{
        struct sample *sample = &cpu->sample;

        sample->core_avg_perf = div_ext_fp(sample->aperf, sample->mperf);
}

static inline bool intel_pstate_sample(struct cpudata *cpu, u64 time)
{
        u64 aperf, mperf;
        unsigned long flags;
        u64 tsc;

        local_irq_save(flags);
        rdmsrl(MSR_IA32_APERF, aperf);
        rdmsrl(MSR_IA32_MPERF, mperf);
        tsc = rdtsc();
        if (cpu->prev_mperf == mperf || cpu->prev_tsc == tsc) {
                local_irq_restore(flags);
                return false;
        }
        local_irq_restore(flags);

        cpu->last_sample_time = cpu->sample.time;
        cpu->sample.time = time;
        cpu->sample.aperf = aperf;
        cpu->sample.mperf = mperf;
        cpu->sample.tsc =  tsc;
        cpu->sample.aperf -= cpu->prev_aperf;
        cpu->sample.mperf -= cpu->prev_mperf;
        cpu->sample.tsc -= cpu->prev_tsc;

        cpu->prev_aperf = aperf;
        cpu->prev_mperf = mperf;
        cpu->prev_tsc = tsc;
        /*
         * First time this function is invoked in a given cycle, all of the
         * previous sample data fields are equal to zero or stale and they must
         * be populated with meaningful numbers for things to work, so assume
         * that sample.time will always be reset before setting the utilization
         * update hook and make the caller skip the sample then.
         */
        return !!cpu->last_sample_time;
}

static inline int32_t get_avg_frequency(struct cpudata *cpu)
{
        return mul_ext_fp(cpu->sample.core_avg_perf,
                          cpu->pstate.max_pstate_physical * cpu->pstate.scaling);
}

static inline int32_t get_avg_pstate(struct cpudata *cpu)
{
        return mul_ext_fp(cpu->pstate.max_pstate_physical,
                          cpu->sample.core_avg_perf);
}

static inline int32_t get_target_pstate_use_cpu_load(struct cpudata *cpu)
{
        struct sample *sample = &cpu->sample;
        int32_t busy_frac, boost;
        int target, avg_pstate;

        busy_frac = div_fp(sample->mperf, sample->tsc);

        boost = cpu->iowait_boost;
        cpu->iowait_boost >>= 1;

        if (busy_frac < boost)
                busy_frac = boost;

        sample->busy_scaled = busy_frac * 100;

        target = limits->no_turbo || limits->turbo_disabled ?
                        cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
        target += target >> 2;
        target = mul_fp(target, busy_frac);
        if (target < cpu->pstate.min_pstate)
                target = cpu->pstate.min_pstate;

        /*
         * If the average P-state during the previous cycle was higher than the
         * current target, add 50% of the difference to the target to reduce
         * possible performance oscillations and offset possible performance
         * loss related to moving the workload from one CPU to another within
         * a package/module.
         */
        avg_pstate = get_avg_pstate(cpu);
        if (avg_pstate > target)
                target += (avg_pstate - target) >> 1;

        return target;
}

static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu)
{
        int32_t perf_scaled, max_pstate, current_pstate, sample_ratio;
        u64 duration_ns;

        /*
         * perf_scaled is the ratio of the average P-state during the last
         * sampling period to the P-state requested last time (in percent).
         *
         * That measures the system's response to the previous P-state
         * selection.
         */
        max_pstate = cpu->pstate.max_pstate_physical;
        current_pstate = cpu->pstate.current_pstate;
        perf_scaled = mul_ext_fp(cpu->sample.core_avg_perf,
                               div_fp(100 * max_pstate, current_pstate));

        /*
         * Since our utilization update callback will not run unless we are
         * in C0, check if the actual elapsed time is significantly greater (3x)
         * than our sample interval.  If it is, then we were idle for a long
         * enough period of time to adjust our performance metric.
         */
        duration_ns = cpu->sample.time - cpu->last_sample_time;
        if ((s64)duration_ns > pid_params.sample_rate_ns * 3) {
                sample_ratio = div_fp(pid_params.sample_rate_ns, duration_ns);
                perf_scaled = mul_fp(perf_scaled, sample_ratio);
        } else {
                sample_ratio = div_fp(100 * cpu->sample.mperf, cpu->sample.tsc);
                if (sample_ratio < int_tofp(1))
                        perf_scaled = 0;
        }

        cpu->sample.busy_scaled = perf_scaled;
        return cpu->pstate.current_pstate - pid_calc(&cpu->pid, perf_scaled);
}

static inline void intel_pstate_update_pstate(struct cpudata *cpu, int pstate)
{
        int max_perf, min_perf;

        update_turbo_state();

        intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
        pstate = clamp_t(int, pstate, min_perf, max_perf);
        trace_cpu_frequency(pstate * cpu->pstate.scaling, cpu->cpu);
        if (pstate == cpu->pstate.current_pstate)
                return;

        cpu->pstate.current_pstate = pstate;
        wrmsrl(MSR_IA32_PERF_CTL, pstate_funcs.get_val(cpu, pstate));
}

static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
{
        int from, target_pstate;
        struct sample *sample;

        from = cpu->pstate.current_pstate;

        target_pstate = pstate_funcs.get_target_pstate(cpu);

        intel_pstate_update_pstate(cpu, target_pstate);

        sample = &cpu->sample;
        trace_pstate_sample(mul_ext_fp(100, sample->core_avg_perf),
                fp_toint(sample->busy_scaled),
                from,
                cpu->pstate.current_pstate,
                sample->mperf,
                sample->aperf,
                sample->tsc,
                get_avg_frequency(cpu),
                fp_toint(cpu->iowait_boost * 100));
}

static void intel_pstate_update_util(struct update_util_data *data, u64 time,
                                     unsigned int flags)
{
        struct cpudata *cpu = container_of(data, struct cpudata, update_util);
        u64 delta_ns;

        if (pid_params.boost_iowait) {
                if (flags & SCHED_CPUFREQ_IOWAIT) {
                        cpu->iowait_boost = int_tofp(1);
                } else if (cpu->iowait_boost) {
                        /* Clear iowait_boost if the CPU may have been idle. */
                        delta_ns = time - cpu->last_update;
                        if (delta_ns > TICK_NSEC)
                                cpu->iowait_boost = 0;
                }
                cpu->last_update = time;
        }

        delta_ns = time - cpu->sample.time;
        if ((s64)delta_ns >= pid_params.sample_rate_ns) {
                bool sample_taken = intel_pstate_sample(cpu, time);

                if (sample_taken) {
                        intel_pstate_calc_avg_perf(cpu);
                        if (!hwp_active)
                                intel_pstate_adjust_busy_pstate(cpu);
                }
        }
}

#define ICPU(model, policy) \
        { X86_VENDOR_INTEL, 6, model, X86_FEATURE_APERFMPERF,\
                        (unsigned long)&policy }

static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
        ICPU(INTEL_FAM6_SANDYBRIDGE,            core_params),
        ICPU(INTEL_FAM6_SANDYBRIDGE_X,          core_params),
        ICPU(INTEL_FAM6_ATOM_SILVERMONT1,       silvermont_params),
        ICPU(INTEL_FAM6_IVYBRIDGE,              core_params),
        ICPU(INTEL_FAM6_HASWELL_CORE,           core_params),
        ICPU(INTEL_FAM6_BROADWELL_CORE,         core_params),
        ICPU(INTEL_FAM6_IVYBRIDGE_X,            core_params),
        ICPU(INTEL_FAM6_HASWELL_X,              core_params),
        ICPU(INTEL_FAM6_HASWELL_ULT,            core_params),
        ICPU(INTEL_FAM6_HASWELL_GT3E,           core_params),
        ICPU(INTEL_FAM6_BROADWELL_GT3E,         core_params),
        ICPU(INTEL_FAM6_ATOM_AIRMONT,           airmont_params),
        ICPU(INTEL_FAM6_SKYLAKE_MOBILE,         core_params),
        ICPU(INTEL_FAM6_BROADWELL_X,            core_params),
        ICPU(INTEL_FAM6_SKYLAKE_DESKTOP,        core_params),
        ICPU(INTEL_FAM6_BROADWELL_XEON_D,       core_params),
        ICPU(INTEL_FAM6_XEON_PHI_KNL,           knl_params),
        ICPU(INTEL_FAM6_ATOM_GOLDMONT,          bxt_params),
        {}
};
MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);

static const struct x86_cpu_id intel_pstate_cpu_oob_ids[] __initconst = {
        ICPU(INTEL_FAM6_BROADWELL_XEON_D, core_params),
        ICPU(INTEL_FAM6_BROADWELL_X, core_params),
        ICPU(INTEL_FAM6_SKYLAKE_X, core_params),
        {}
};

static int intel_pstate_init_cpu(unsigned int cpunum)
{
        struct cpudata *cpu;

        if (!all_cpu_data[cpunum])
                all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata),
                                               GFP_KERNEL);
        if (!all_cpu_data[cpunum])
                return -ENOMEM;

        cpu = all_cpu_data[cpunum];

        cpu->cpu = cpunum;

        if (hwp_active) {
                intel_pstate_hwp_enable(cpu);
                pid_params.sample_rate_ms = 50;
                pid_params.sample_rate_ns = 50 * NSEC_PER_MSEC;
        }

        intel_pstate_get_cpu_pstates(cpu);

        intel_pstate_busy_pid_reset(cpu);

        pr_debug("controlling: cpu %d\n", cpunum);

        return 0;
}

static unsigned int intel_pstate_get(unsigned int cpu_num)
{
        struct cpudata *cpu = all_cpu_data[cpu_num];

        return cpu ? get_avg_frequency(cpu) : 0;
}

static void intel_pstate_set_update_util_hook(unsigned int cpu_num)
{
        struct cpudata *cpu = all_cpu_data[cpu_num];

        if (cpu->update_util_set)
                return;

        /* Prevent intel_pstate_update_util() from using stale data. */
        cpu->sample.time = 0;
        cpufreq_add_update_util_hook(cpu_num, &cpu->update_util,
                                     intel_pstate_update_util);
        cpu->update_util_set = true;
}

static void intel_pstate_clear_update_util_hook(unsigned int cpu)
{
        struct cpudata *cpu_data = all_cpu_data[cpu];

        if (!cpu_data->update_util_set)
                return;

        cpufreq_remove_update_util_hook(cpu);
        cpu_data->update_util_set = false;
        synchronize_sched();
}

static void intel_pstate_set_performance_limits(struct perf_limits *limits)
{
        limits->no_turbo = 0;
        limits->turbo_disabled = 0;
        limits->max_perf_pct = 100;
        limits->max_perf = int_tofp(1);
        limits->min_perf_pct = 100;
        limits->min_perf = int_tofp(1);
        limits->max_policy_pct = 100;
        limits->max_sysfs_pct = 100;
        limits->min_policy_pct = 0;
        limits->min_sysfs_pct = 0;
}

static int intel_pstate_set_policy(struct cpufreq_policy *policy)
{
        struct cpudata *cpu;

        if (!policy->cpuinfo.max_freq)
                return -ENODEV;

        pr_debug("set_policy cpuinfo.max %u policy->max %u\n",
                 policy->cpuinfo.max_freq, policy->max);

        cpu = all_cpu_data[0];
        if (cpu->pstate.max_pstate_physical > cpu->pstate.max_pstate &&
            policy->max < policy->cpuinfo.max_freq &&
            policy->max > cpu->pstate.max_pstate * cpu->pstate.scaling) {
                pr_debug("policy->max > max non turbo frequency\n");
                policy->max = policy->cpuinfo.max_freq;
        }

        if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
                limits = &performance_limits;
                if (policy->max >= policy->cpuinfo.max_freq) {
                        pr_debug("set performance\n");
                        intel_pstate_set_performance_limits(limits);
                        goto out;
                }
        } else {
                pr_debug("set powersave\n");
                limits = &powersave_limits;
        }

        limits->min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
        limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, 0 , 100);
        limits->max_policy_pct = DIV_ROUND_UP(policy->max * 100,
                                              policy->cpuinfo.max_freq);
        limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0 , 100);

        /* Normalize user input to [min_policy_pct, max_policy_pct] */
        limits->min_perf_pct = max(limits->min_policy_pct,
                                   limits->min_sysfs_pct);
        limits->min_perf_pct = min(limits->max_policy_pct,
                                   limits->min_perf_pct);
        limits->max_perf_pct = min(limits->max_policy_pct,
                                   limits->max_sysfs_pct);
        limits->max_perf_pct = max(limits->min_policy_pct,
                                   limits->max_perf_pct);

        /* Make sure min_perf_pct <= max_perf_pct */
        limits->min_perf_pct = min(limits->max_perf_pct, limits->min_perf_pct);

        limits->min_perf = div_fp(limits->min_perf_pct, 100);
        limits->max_perf = div_fp(limits->max_perf_pct, 100);
        limits->max_perf = round_up(limits->max_perf, FRAC_BITS);

 out:
        intel_pstate_set_update_util_hook(policy->cpu);

        intel_pstate_hwp_set_policy(policy);

        return 0;
}

static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
{
        cpufreq_verify_within_cpu_limits(policy);

        if (policy->policy != CPUFREQ_POLICY_POWERSAVE &&
            policy->policy != CPUFREQ_POLICY_PERFORMANCE)
                return -EINVAL;

        return 0;
}

static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
{
        int cpu_num = policy->cpu;
        struct cpudata *cpu = all_cpu_data[cpu_num];

        pr_debug("CPU %d exiting\n", cpu_num);

        intel_pstate_clear_update_util_hook(cpu_num);

        if (hwp_active)
                return;

        intel_pstate_set_min_pstate(cpu);
}

static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
{
        struct cpudata *cpu;
        int rc;

        rc = intel_pstate_init_cpu(policy->cpu);
        if (rc)
                return rc;

        cpu = all_cpu_data[policy->cpu];

        if (limits->min_perf_pct == 100 && limits->max_perf_pct == 100)
                policy->policy = CPUFREQ_POLICY_PERFORMANCE;
        else
                policy->policy = CPUFREQ_POLICY_POWERSAVE;

        policy->min = cpu->pstate.min_pstate * cpu->pstate.scaling;
        policy->max = cpu->pstate.turbo_pstate * cpu->pstate.scaling;

        /* cpuinfo and default policy values */
        policy->cpuinfo.min_freq = cpu->pstate.min_pstate * cpu->pstate.scaling;
        update_turbo_state();
        policy->cpuinfo.max_freq = limits->turbo_disabled ?
                        cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
        policy->cpuinfo.max_freq *= cpu->pstate.scaling;

        intel_pstate_init_acpi_perf_limits(policy);
        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
        cpumask_set_cpu(policy->cpu, policy->cpus);

        return 0;
}

static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
{
        intel_pstate_exit_perf_limits(policy);

        return 0;
}

static struct cpufreq_driver intel_pstate_driver = {
        .flags          = CPUFREQ_CONST_LOOPS,
        .verify         = intel_pstate_verify_policy,
        .setpolicy      = intel_pstate_set_policy,
        .resume         = intel_pstate_hwp_set_policy,
        .get            = intel_pstate_get,
        .init           = intel_pstate_cpu_init,
        .exit           = intel_pstate_cpu_exit,
        .stop_cpu       = intel_pstate_stop_cpu,
        .name           = "intel_pstate",
};

static int no_load __initdata;
static int no_hwp __initdata;
static int hwp_only __initdata;
static unsigned int force_load __initdata;

static int __init intel_pstate_msrs_not_valid(void)
{
        if (!pstate_funcs.get_max() ||
            !pstate_funcs.get_min() ||
            !pstate_funcs.get_turbo())
                return -ENODEV;

        return 0;
}

static void __init copy_pid_params(struct pstate_adjust_policy *policy)
{
        pid_params.sample_rate_ms = policy->sample_rate_ms;
        pid_params.sample_rate_ns = pid_params.sample_rate_ms * NSEC_PER_MSEC;
        pid_params.p_gain_pct = policy->p_gain_pct;
        pid_params.i_gain_pct = policy->i_gain_pct;
        pid_params.d_gain_pct = policy->d_gain_pct;
        pid_params.deadband = policy->deadband;
        pid_params.setpoint = policy->setpoint;
}

static void __init copy_cpu_funcs(struct pstate_funcs *funcs)
{
        pstate_funcs.get_max   = funcs->get_max;
        pstate_funcs.get_max_physical = funcs->get_max_physical;
        pstate_funcs.get_min   = funcs->get_min;
        pstate_funcs.get_turbo = funcs->get_turbo;
        pstate_funcs.get_scaling = funcs->get_scaling;
        pstate_funcs.get_val   = funcs->get_val;
        pstate_funcs.get_vid   = funcs->get_vid;
        pstate_funcs.get_target_pstate = funcs->get_target_pstate;

}

#ifdef CONFIG_ACPI

static bool __init intel_pstate_no_acpi_pss(void)
{
        int i;

        for_each_possible_cpu(i) {
                acpi_status status;
                union acpi_object *pss;
                struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
                struct acpi_processor *pr = per_cpu(processors, i);

                if (!pr)
                        continue;

                status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
                if (ACPI_FAILURE(status))
                        continue;

                pss = buffer.pointer;
                if (pss && pss->type == ACPI_TYPE_PACKAGE) {
                        kfree(pss);
                        return false;
                }

                kfree(pss);
        }

        return true;
}

static bool __init intel_pstate_has_acpi_ppc(void)
{
        int i;

        for_each_possible_cpu(i) {
                struct acpi_processor *pr = per_cpu(processors, i);

                if (!pr)
                        continue;
                if (acpi_has_method(pr->handle, "_PPC"))
                        return true;
        }
        return false;
}

enum {
        PSS,
        PPC,
};

struct hw_vendor_info {
        u16  valid;
        char oem_id[ACPI_OEM_ID_SIZE];
        char oem_table_id[ACPI_OEM_TABLE_ID_SIZE];
        int  oem_pwr_table;
};

/* Hardware vendor-specific info that has its own power management modes */
static struct hw_vendor_info vendor_info[] __initdata = {
        {1, "HP    ", "ProLiant", PSS},
        {1, "ORACLE", "X4-2    ", PPC},
        {1, "ORACLE", "X4-2L   ", PPC},
        {1, "ORACLE", "X4-2B   ", PPC},
        {1, "ORACLE", "X3-2    ", PPC},
        {1, "ORACLE", "X3-2L   ", PPC},
        {1, "ORACLE", "X3-2B   ", PPC},
        {1, "ORACLE", "X4470M2 ", PPC},
        {1, "ORACLE", "X4270M3 ", PPC},
        {1, "ORACLE", "X4270M2 ", PPC},
        {1, "ORACLE", "X4170M2 ", PPC},
        {1, "ORACLE", "X4170 M3", PPC},
        {1, "ORACLE", "X4275 M3", PPC},
        {1, "ORACLE", "X6-2    ", PPC},
        {1, "ORACLE", "Sudbury ", PPC},
        {0, "", ""},
};

static bool __init intel_pstate_platform_pwr_mgmt_exists(void)
{
        struct acpi_table_header hdr;
        struct hw_vendor_info *v_info;
        const struct x86_cpu_id *id;
        u64 misc_pwr;

        id = x86_match_cpu(intel_pstate_cpu_oob_ids);
        if (id) {
                rdmsrl(MSR_MISC_PWR_MGMT, misc_pwr);
                if ( misc_pwr & (1 << 8))
                        return true;
        }

        if (acpi_disabled ||
            ACPI_FAILURE(acpi_get_table_header(ACPI_SIG_FADT, 0, &hdr)))
                return false;

        for (v_info = vendor_info; v_info->valid; v_info++) {
                if (!strncmp(hdr.oem_id, v_info->oem_id, ACPI_OEM_ID_SIZE) &&
                        !strncmp(hdr.oem_table_id, v_info->oem_table_id,
                                                ACPI_OEM_TABLE_ID_SIZE))
                        switch (v_info->oem_pwr_table) {
                        case PSS:
                                return intel_pstate_no_acpi_pss();
                        case PPC:
                                return intel_pstate_has_acpi_ppc() &&
                                        (!force_load);
                        }
        }

        return false;
}
#else /* CONFIG_ACPI not enabled */
static inline bool intel_pstate_platform_pwr_mgmt_exists(void) { return false; }
static inline bool intel_pstate_has_acpi_ppc(void) { return false; }
#endif /* CONFIG_ACPI */

static const struct x86_cpu_id hwp_support_ids[] __initconst = {
        { X86_VENDOR_INTEL, 6, X86_MODEL_ANY, X86_FEATURE_HWP },
        {}
};

static int __init intel_pstate_init(void)
{
        int cpu, rc = 0;
        const struct x86_cpu_id *id;
        struct cpu_defaults *cpu_def;

        if (no_load)
                return -ENODEV;

        if (x86_match_cpu(hwp_support_ids) && !no_hwp) {
                copy_cpu_funcs(&core_params.funcs);
                hwp_active++;
                goto hwp_cpu_matched;
        }

        id = x86_match_cpu(intel_pstate_cpu_ids);
        if (!id)
                return -ENODEV;

        cpu_def = (struct cpu_defaults *)id->driver_data;

        copy_pid_params(&cpu_def->pid_policy);
        copy_cpu_funcs(&cpu_def->funcs);

        if (intel_pstate_msrs_not_valid())
                return -ENODEV;

hwp_cpu_matched:
        /*
         * The Intel pstate driver will be ignored if the platform
         * firmware has its own power management modes.
         */
        if (intel_pstate_platform_pwr_mgmt_exists())
                return -ENODEV;

        pr_info("Intel P-state driver initializing\n");

        all_cpu_data = vzalloc(sizeof(void *) * num_possible_cpus());
        if (!all_cpu_data)
                return -ENOMEM;

        if (!hwp_active && hwp_only)
                goto out;

        rc = cpufreq_register_driver(&intel_pstate_driver);
        if (rc)
                goto out;

        intel_pstate_debug_expose_params();
        intel_pstate_sysfs_expose_params();

        if (hwp_active)
                pr_info("HWP enabled\n");

        return rc;
out:
        get_online_cpus();
        for_each_online_cpu(cpu) {
                if (all_cpu_data[cpu]) {
                        intel_pstate_clear_update_util_hook(cpu);
                        kfree(all_cpu_data[cpu]);
                }
        }

        put_online_cpus();
        vfree(all_cpu_data);
        return -ENODEV;
}
device_initcall(intel_pstate_init);

static int __init intel_pstate_setup(char *str)
{
        if (!str)
                return -EINVAL;

        if (!strcmp(str, "disable"))
                no_load = 1;
        if (!strcmp(str, "no_hwp")) {
                pr_info("HWP disabled\n");
                no_hwp = 1;
        }
        if (!strcmp(str, "force"))
                force_load = 1;
        if (!strcmp(str, "hwp_only"))
                hwp_only = 1;

#ifdef CONFIG_ACPI
        if (!strcmp(str, "support_acpi_ppc"))
                acpi_ppc = true;
#endif

        return 0;
}
early_param("intel_pstate", intel_pstate_setup);

MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@intel.com>");
MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
MODULE_LICENSE("GPL");