// SPDX-License-Identifier: GPL-2.0-only
/*
 * intel_pstate.c: Native P state management for Intel processors
 *
 * (C) Copyright 2012 Intel Corporation
 * Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
 */

#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/cpufreq.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/acpi.h>
#include <linux/vmalloc.h>
#include <linux/pm_qos.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 INTEL_PSTATE_SAMPLING_INTERVAL  (10 * NSEC_PER_MSEC)

#define INTEL_CPUFREQ_TRANSITION_LATENCY        20000
#define INTEL_CPUFREQ_TRANSITION_DELAY          500

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

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

#define ONE_EIGHTH_FP ((int64_t)1 << (FRAC_BITS - 3))

#define EXT_BITS 6
#define EXT_FRAC_BITS (EXT_BITS + FRAC_BITS)
#define fp_ext_toint(X) ((X) >> EXT_FRAC_BITS)
#define int_ext_tofp(X) ((int64_t)(X) << EXT_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 int32_t percent_fp(int percent)
{
        return div_fp(percent, 100);
}

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);
}

static inline int32_t percent_ext_fp(int percent)
{
        return div_ext_fp(percent, 100);
}

/**
 * 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
 * @max_freq:           @max_pstate frequency in cpufreq units
 * @turbo_freq:         @turbo_pstate frequency in cpufreq units
 *
 * 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;
        unsigned int max_freq;
        unsigned int turbo_freq;
};

/**
 * 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 global_params - Global parameters, mostly tunable via sysfs.
 * @no_turbo:           Whether or not to use turbo P-states.
 * @turbo_disabled:     Whether or not turbo P-states are available at all,
 *                      based on the MSR_IA32_MISC_ENABLE value and whether or
 *                      not the maximum reported turbo P-state is different from
 *                      the maximum reported non-turbo one.
 * @turbo_disabled_mf:  The @turbo_disabled value reflected by cpuinfo.max_freq.
 * @min_perf_pct:       Minimum capacity limit in percent of the maximum turbo
 *                      P-state capacity.
 * @max_perf_pct:       Maximum capacity limit in percent of the maximum turbo
 *                      P-state capacity.
 */
struct global_params {
        bool no_turbo;
        bool turbo_disabled;
        bool turbo_disabled_mf;
        int max_perf_pct;
        int min_perf_pct;
};

/**
 * struct cpudata -     Per CPU instance data storage
 * @cpu:                CPU number for this instance data
 * @policy:             CPUFreq policy value
 * @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
 * @last_sample_time:   Last Sample time
 * @aperf_mperf_shift:  Number of clock cycles after aperf, merf is incremented
 *                      This shift is a multiplier to mperf delta to
 *                      calculate CPU busy.
 * @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
 * @min_perf_ratio:     Minimum capacity in terms of PERF or HWP ratios
 * @max_perf_ratio:     Maximum capacity in terms of PERF or HWP ratios
 * @acpi_perf_data:     Stores ACPI perf information read from _PSS
 * @valid_pss_table:    Set to true for valid ACPI _PSS entries found
 * @epp_powersave:      Last saved HWP energy performance preference
 *                      (EPP) or energy performance bias (EPB),
 *                      when policy switched to performance
 * @epp_policy:         Last saved policy used to set EPP/EPB
 * @epp_default:        Power on default HWP energy performance
 *                      preference/bias
 * @epp_saved:          Saved EPP/EPB during system suspend or CPU offline
 *                      operation
 * @hwp_req_cached:     Cached value of the last HWP Request MSR
 * @hwp_cap_cached:     Cached value of the last HWP Capabilities MSR
 * @last_io_update:     Last time when IO wake flag was set
 * @sched_flags:        Store scheduler flags for possible cross CPU update
 * @hwp_boost_min:      Last HWP boosted min performance
 *
 * This structure stores per CPU instance data for all CPUs.
 */
struct cpudata {
        int cpu;

        unsigned int policy;
        struct update_util_data update_util;
        bool   update_util_set;

        struct pstate_data pstate;
        struct vid_data vid;

        u64     last_update;
        u64     last_sample_time;
        u64     aperf_mperf_shift;
        u64     prev_aperf;
        u64     prev_mperf;
        u64     prev_tsc;
        u64     prev_cummulative_iowait;
        struct sample sample;
        int32_t min_perf_ratio;
        int32_t max_perf_ratio;
#ifdef CONFIG_ACPI
        struct acpi_processor_performance acpi_perf_data;
        bool valid_pss_table;
#endif
        unsigned int iowait_boost;
        s16 epp_powersave;
        s16 epp_policy;
        s16 epp_default;
        s16 epp_saved;
        u64 hwp_req_cached;
        u64 hwp_cap_cached;
        u64 last_io_update;
        unsigned int sched_flags;
        u32 hwp_boost_min;
};

static struct cpudata **all_cpu_data;

/**
 * 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
 *
 * 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);
        int (*get_aperf_mperf_shift)(void);
        u64 (*get_val)(struct cpudata*, int pstate);
        void (*get_vid)(struct cpudata *);
};

static struct pstate_funcs pstate_funcs __read_mostly;

static int hwp_active __read_mostly;
static int hwp_mode_bdw __read_mostly;
static bool per_cpu_limits __read_mostly;
static bool hwp_boost __read_mostly;

static struct cpufreq_driver *intel_pstate_driver __read_mostly;

#ifdef CONFIG_ACPI
static bool acpi_ppc;
#endif

static struct global_params global;

static DEFINE_MUTEX(intel_pstate_driver_lock);
static DEFINE_MUTEX(intel_pstate_limits_lock);

#ifdef CONFIG_ACPI

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

        return false;
}

static bool intel_pstate_get_ppc_enable_status(void)
{
        if (intel_pstate_acpi_pm_profile_server())
                return true;

        return acpi_ppc;
}

#ifdef CONFIG_ACPI_CPPC_LIB

/* The work item is needed to avoid CPU hotplug locking issues */
static void intel_pstste_sched_itmt_work_fn(struct work_struct *work)
{
        sched_set_itmt_support();
}

static DECLARE_WORK(sched_itmt_work, intel_pstste_sched_itmt_work_fn);

static void intel_pstate_set_itmt_prio(int cpu)
{
        struct cppc_perf_caps cppc_perf;
        static u32 max_highest_perf = 0, min_highest_perf = U32_MAX;
        int ret;

        ret = cppc_get_perf_caps(cpu, &cppc_perf);
        if (ret)
                return;

        /*
         * The priorities can be set regardless of whether or not
         * sched_set_itmt_support(true) has been called and it is valid to
         * update them at any time after it has been called.
         */
        sched_set_itmt_core_prio(cppc_perf.highest_perf, cpu);

        if (max_highest_perf <= min_highest_perf) {
                if (cppc_perf.highest_perf > max_highest_perf)
                        max_highest_perf = cppc_perf.highest_perf;

                if (cppc_perf.highest_perf < min_highest_perf)
                        min_highest_perf = cppc_perf.highest_perf;

                if (max_highest_perf > min_highest_perf) {
                        /*
                         * This code can be run during CPU online under the
                         * CPU hotplug locks, so sched_set_itmt_support()
                         * cannot be called from here.  Queue up a work item
                         * to invoke it.
                         */
                        schedule_work(&sched_itmt_work);
                }
        }
}

static int intel_pstate_get_cppc_guranteed(int cpu)
{
        struct cppc_perf_caps cppc_perf;
        int ret;

        ret = cppc_get_perf_caps(cpu, &cppc_perf);
        if (ret)
                return ret;

        if (cppc_perf.guaranteed_perf)
                return cppc_perf.guaranteed_perf;

        return cppc_perf.nominal_perf;
}

#else /* CONFIG_ACPI_CPPC_LIB */
static void intel_pstate_set_itmt_prio(int cpu)
{
}
#endif /* CONFIG_ACPI_CPPC_LIB */

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

        if (hwp_active) {
                intel_pstate_set_itmt_prio(policy->cpu);
                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 (!global.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 /* CONFIG_ACPI */
static inline void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
{
}

static inline void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
{
}

static inline bool intel_pstate_acpi_pm_profile_server(void)
{
        return false;
}
#endif /* CONFIG_ACPI */

#ifndef CONFIG_ACPI_CPPC_LIB
static int intel_pstate_get_cppc_guranteed(int cpu)
{
        return -ENOTSUPP;
}
#endif /* CONFIG_ACPI_CPPC_LIB */

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);
        global.turbo_disabled =
                (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE ||
                 cpu->pstate.max_pstate == cpu->pstate.turbo_pstate);
}

static int min_perf_pct_min(void)
{
        struct cpudata *cpu = all_cpu_data[0];
        int turbo_pstate = cpu->pstate.turbo_pstate;

        return turbo_pstate ?
                (cpu->pstate.min_pstate * 100 / turbo_pstate) : 0;
}

static s16 intel_pstate_get_epb(struct cpudata *cpu_data)
{
        u64 epb;
        int ret;

        if (!boot_cpu_has(X86_FEATURE_EPB))
                return -ENXIO;

        ret = rdmsrl_on_cpu(cpu_data->cpu, MSR_IA32_ENERGY_PERF_BIAS, &epb);
        if (ret)
                return (s16)ret;

        return (s16)(epb & 0x0f);
}

static s16 intel_pstate_get_epp(struct cpudata *cpu_data, u64 hwp_req_data)
{
        s16 epp;

        if (boot_cpu_has(X86_FEATURE_HWP_EPP)) {
                /*
                 * When hwp_req_data is 0, means that caller didn't read
                 * MSR_HWP_REQUEST, so need to read and get EPP.
                 */
                if (!hwp_req_data) {
                        epp = rdmsrl_on_cpu(cpu_data->cpu, MSR_HWP_REQUEST,
                                            &hwp_req_data);
                        if (epp)
                                return epp;
                }
                epp = (hwp_req_data >> 24) & 0xff;
        } else {
                /* When there is no EPP present, HWP uses EPB settings */
                epp = intel_pstate_get_epb(cpu_data);
        }

        return epp;
}

static int intel_pstate_set_epb(int cpu, s16 pref)
{
        u64 epb;
        int ret;

        if (!boot_cpu_has(X86_FEATURE_EPB))
                return -ENXIO;

        ret = rdmsrl_on_cpu(cpu, MSR_IA32_ENERGY_PERF_BIAS, &epb);
        if (ret)
                return ret;

        epb = (epb & ~0x0f) | pref;
        wrmsrl_on_cpu(cpu, MSR_IA32_ENERGY_PERF_BIAS, epb);

        return 0;
}

/*
 * EPP/EPB display strings corresponding to EPP index in the
 * energy_perf_strings[]
 *      index           String
 *-------------------------------------
 *      0               default
 *      1               performance
 *      2               balance_performance
 *      3               balance_power
 *      4               power
 */
static const char * const energy_perf_strings[] = {
        "default",
        "performance",
        "balance_performance",
        "balance_power",
        "power",
        NULL
};
static const unsigned int epp_values[] = {
        HWP_EPP_PERFORMANCE,
        HWP_EPP_BALANCE_PERFORMANCE,
        HWP_EPP_BALANCE_POWERSAVE,
        HWP_EPP_POWERSAVE
};

static int intel_pstate_get_energy_pref_index(struct cpudata *cpu_data)
{
        s16 epp;
        int index = -EINVAL;

        epp = intel_pstate_get_epp(cpu_data, 0);
        if (epp < 0)
                return epp;

        if (boot_cpu_has(X86_FEATURE_HWP_EPP)) {
                if (epp == HWP_EPP_PERFORMANCE)
                        return 1;
                if (epp <= HWP_EPP_BALANCE_PERFORMANCE)
                        return 2;
                if (epp <= HWP_EPP_BALANCE_POWERSAVE)
                        return 3;
                else
                        return 4;
        } else if (boot_cpu_has(X86_FEATURE_EPB)) {
                /*
                 * Range:
                 *      0x00-0x03       :       Performance
                 *      0x04-0x07       :       Balance performance
                 *      0x08-0x0B       :       Balance power
                 *      0x0C-0x0F       :       Power
                 * The EPB is a 4 bit value, but our ranges restrict the
                 * value which can be set. Here only using top two bits
                 * effectively.
                 */
                index = (epp >> 2) + 1;
        }

        return index;
}

static int intel_pstate_set_energy_pref_index(struct cpudata *cpu_data,
                                              int pref_index)
{
        int epp = -EINVAL;
        int ret;

        if (!pref_index)
                epp = cpu_data->epp_default;

        mutex_lock(&intel_pstate_limits_lock);

        if (boot_cpu_has(X86_FEATURE_HWP_EPP)) {
                u64 value;

                ret = rdmsrl_on_cpu(cpu_data->cpu, MSR_HWP_REQUEST, &value);
                if (ret)
                        goto return_pref;

                value &= ~GENMASK_ULL(31, 24);

                if (epp == -EINVAL)
                        epp = epp_values[pref_index - 1];

                value |= (u64)epp << 24;
                ret = wrmsrl_on_cpu(cpu_data->cpu, MSR_HWP_REQUEST, value);
        } else {
                if (epp == -EINVAL)
                        epp = (pref_index - 1) << 2;
                ret = intel_pstate_set_epb(cpu_data->cpu, epp);
        }
return_pref:
        mutex_unlock(&intel_pstate_limits_lock);

        return ret;
}

static ssize_t show_energy_performance_available_preferences(
                                struct cpufreq_policy *policy, char *buf)
{
        int i = 0;
        int ret = 0;

        while (energy_perf_strings[i] != NULL)
                ret += sprintf(&buf[ret], "%s ", energy_perf_strings[i++]);

        ret += sprintf(&buf[ret], "\n");

        return ret;
}

cpufreq_freq_attr_ro(energy_performance_available_preferences);

static ssize_t store_energy_performance_preference(
                struct cpufreq_policy *policy, const char *buf, size_t count)
{
        struct cpudata *cpu_data = all_cpu_data[policy->cpu];
        char str_preference[21];
        int ret;

        ret = sscanf(buf, "%20s", str_preference);
        if (ret != 1)
                return -EINVAL;

        ret = match_string(energy_perf_strings, -1, str_preference);
        if (ret < 0)
                return ret;

        intel_pstate_set_energy_pref_index(cpu_data, ret);
        return count;
}

static ssize_t show_energy_performance_preference(
                                struct cpufreq_policy *policy, char *buf)
{
        struct cpudata *cpu_data = all_cpu_data[policy->cpu];
        int preference;

        preference = intel_pstate_get_energy_pref_index(cpu_data);
        if (preference < 0)
                return preference;

        return  sprintf(buf, "%s\n", energy_perf_strings[preference]);
}

cpufreq_freq_attr_rw(energy_performance_preference);

static ssize_t show_base_frequency(struct cpufreq_policy *policy, char *buf)
{
        struct cpudata *cpu;
        u64 cap;
        int ratio;

        ratio = intel_pstate_get_cppc_guranteed(policy->cpu);
        if (ratio <= 0) {
                rdmsrl_on_cpu(policy->cpu, MSR_HWP_CAPABILITIES, &cap);
                ratio = HWP_GUARANTEED_PERF(cap);
        }

        cpu = all_cpu_data[policy->cpu];

        return sprintf(buf, "%d\n", ratio * cpu->pstate.scaling);
}

cpufreq_freq_attr_ro(base_frequency);

static struct freq_attr *hwp_cpufreq_attrs[] = {
        &energy_performance_preference,
        &energy_performance_available_preferences,
        &base_frequency,
        NULL,
};

static void intel_pstate_get_hwp_max(unsigned int cpu, int *phy_max,
                                     int *current_max)
{
        u64 cap;

        rdmsrl_on_cpu(cpu, MSR_HWP_CAPABILITIES, &cap);
        WRITE_ONCE(all_cpu_data[cpu]->hwp_cap_cached, cap);
        if (global.no_turbo)
                *current_max = HWP_GUARANTEED_PERF(cap);
        else
                *current_max = HWP_HIGHEST_PERF(cap);

        *phy_max = HWP_HIGHEST_PERF(cap);
}

static void intel_pstate_hwp_set(unsigned int cpu)
{
        struct cpudata *cpu_data = all_cpu_data[cpu];
        int max, min;
        u64 value;
        s16 epp;

        max = cpu_data->max_perf_ratio;
        min = cpu_data->min_perf_ratio;

        if (cpu_data->policy == CPUFREQ_POLICY_PERFORMANCE)
                min = max;

        rdmsrl_on_cpu(cpu, MSR_HWP_REQUEST, &value);

        value &= ~HWP_MIN_PERF(~0L);
        value |= HWP_MIN_PERF(min);

        value &= ~HWP_MAX_PERF(~0L);
        value |= HWP_MAX_PERF(max);

        if (cpu_data->epp_policy == cpu_data->policy)
                goto skip_epp;

        cpu_data->epp_policy = cpu_data->policy;

        if (cpu_data->epp_saved >= 0) {
                epp = cpu_data->epp_saved;
                cpu_data->epp_saved = -EINVAL;
                goto update_epp;
        }

        if (cpu_data->policy == CPUFREQ_POLICY_PERFORMANCE) {
                epp = intel_pstate_get_epp(cpu_data, value);
                cpu_data->epp_powersave = epp;
                /* If EPP read was failed, then don't try to write */
                if (epp < 0)
                        goto skip_epp;

                epp = 0;
        } else {
                /* skip setting EPP, when saved value is invalid */
                if (cpu_data->epp_powersave < 0)
                        goto skip_epp;

                /*
                 * No need to restore EPP when it is not zero. This
                 * means:
                 *  - Policy is not changed
                 *  - user has manually changed
                 *  - Error reading EPB
                 */
                epp = intel_pstate_get_epp(cpu_data, value);
                if (epp)
                        goto skip_epp;

                epp = cpu_data->epp_powersave;
        }
update_epp:
        if (boot_cpu_has(X86_FEATURE_HWP_EPP)) {
                value &= ~GENMASK_ULL(31, 24);
                value |= (u64)epp << 24;
        } else {
                intel_pstate_set_epb(cpu, epp);
        }
skip_epp:
        WRITE_ONCE(cpu_data->hwp_req_cached, value);
        wrmsrl_on_cpu(cpu, MSR_HWP_REQUEST, value);
}

static void intel_pstate_hwp_force_min_perf(int cpu)
{
        u64 value;
        int min_perf;

        value = all_cpu_data[cpu]->hwp_req_cached;
        value &= ~GENMASK_ULL(31, 0);
        min_perf = HWP_LOWEST_PERF(all_cpu_data[cpu]->hwp_cap_cached);

        /* Set hwp_max = hwp_min */
        value |= HWP_MAX_PERF(min_perf);
        value |= HWP_MIN_PERF(min_perf);

        /* Set EPP to min */
        if (boot_cpu_has(X86_FEATURE_HWP_EPP))
                value |= HWP_ENERGY_PERF_PREFERENCE(HWP_EPP_POWERSAVE);

        wrmsrl_on_cpu(cpu, MSR_HWP_REQUEST, value);
}

static int intel_pstate_hwp_save_state(struct cpufreq_policy *policy)
{
        struct cpudata *cpu_data = all_cpu_data[policy->cpu];

        if (!hwp_active)
                return 0;

        cpu_data->epp_saved = intel_pstate_get_epp(cpu_data, 0);

        return 0;
}

static void intel_pstate_hwp_enable(struct cpudata *cpudata);

static int intel_pstate_resume(struct cpufreq_policy *policy)
{
        if (!hwp_active)
                return 0;

        mutex_lock(&intel_pstate_limits_lock);

        if (policy->cpu == 0)
                intel_pstate_hwp_enable(all_cpu_data[policy->cpu]);

        all_cpu_data[policy->cpu]->epp_policy = 0;
        intel_pstate_hwp_set(policy->cpu);

        mutex_unlock(&intel_pstate_limits_lock);

        return 0;
}

static void intel_pstate_update_policies(void)
{
        int cpu;

        for_each_possible_cpu(cpu)
                cpufreq_update_policy(cpu);
}

static void intel_pstate_update_max_freq(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
        struct cpudata *cpudata;

        if (!policy)
                return;

        cpudata = all_cpu_data[cpu];
        policy->cpuinfo.max_freq = global.turbo_disabled_mf ?
                        cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;

        refresh_frequency_limits(policy);

        cpufreq_cpu_release(policy);
}

static void intel_pstate_update_limits(unsigned int cpu)
{
        mutex_lock(&intel_pstate_driver_lock);

        update_turbo_state();
        /*
         * If turbo has been turned on or off globally, policy limits for
         * all CPUs need to be updated to reflect that.
         */
        if (global.turbo_disabled_mf != global.turbo_disabled) {
                global.turbo_disabled_mf = global.turbo_disabled;
                for_each_possible_cpu(cpu)
                        intel_pstate_update_max_freq(cpu);
        } else {
                cpufreq_update_policy(cpu);
        }

        mutex_unlock(&intel_pstate_driver_lock);
}

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

static ssize_t intel_pstate_show_status(char *buf);
static int intel_pstate_update_status(const char *buf, size_t size);

static ssize_t show_status(struct kobject *kobj,
                           struct kobj_attribute *attr, char *buf)
{
        ssize_t ret;

        mutex_lock(&intel_pstate_driver_lock);
        ret = intel_pstate_show_status(buf);
        mutex_unlock(&intel_pstate_driver_lock);

        return ret;
}

static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
                            const char *buf, size_t count)
{
        char *p = memchr(buf, '\n', count);
        int ret;

        mutex_lock(&intel_pstate_driver_lock);
        ret = intel_pstate_update_status(buf, p ? p - buf : count);
        mutex_unlock(&intel_pstate_driver_lock);

        return ret < 0 ? ret : count;
}

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

        mutex_lock(&intel_pstate_driver_lock);

        if (!intel_pstate_driver) {
                mutex_unlock(&intel_pstate_driver_lock);
                return -EAGAIN;
        }

        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)));

        mutex_unlock(&intel_pstate_driver_lock);

        return sprintf(buf, "%u\n", turbo_pct);
}

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

        mutex_lock(&intel_pstate_driver_lock);

        if (!intel_pstate_driver) {
                mutex_unlock(&intel_pstate_driver_lock);
                return -EAGAIN;
        }

        cpu = all_cpu_data[0];
        total = cpu->pstate.turbo_pstate - cpu->pstate.min_pstate + 1;

        mutex_unlock(&intel_pstate_driver_lock);

        return sprintf(buf, "%u\n", total);
}

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

        mutex_lock(&intel_pstate_driver_lock);

        if (!intel_pstate_driver) {
                mutex_unlock(&intel_pstate_driver_lock);
                return -EAGAIN;
        }

        update_turbo_state();
        if (global.turbo_disabled)
                ret = sprintf(buf, "%u\n", global.turbo_disabled);
        else
                ret = sprintf(buf, "%u\n", global.no_turbo);

        mutex_unlock(&intel_pstate_driver_lock);

        return ret;
}

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

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

        mutex_lock(&intel_pstate_driver_lock);

        if (!intel_pstate_driver) {
                mutex_unlock(&intel_pstate_driver_lock);
                return -EAGAIN;
        }

        mutex_lock(&intel_pstate_limits_lock);

        update_turbo_state();
        if (global.turbo_disabled) {
                pr_warn("Turbo disabled by BIOS or unavailable on processor\n");
                mutex_unlock(&intel_pstate_limits_lock);
                mutex_unlock(&intel_pstate_driver_lock);
                return -EPERM;
        }

        global.no_turbo = clamp_t(int, input, 0, 1);

        if (global.no_turbo) {
                struct cpudata *cpu = all_cpu_data[0];
                int pct = cpu->pstate.max_pstate * 100 / cpu->pstate.turbo_pstate;

                /* Squash the global minimum into the permitted range. */
                if (global.min_perf_pct > pct)
                        global.min_perf_pct = pct;
        }

        mutex_unlock(&intel_pstate_limits_lock);

        intel_pstate_update_policies();

        mutex_unlock(&intel_pstate_driver_lock);

        return count;
}

static struct cpufreq_driver intel_pstate;

static void update_qos_request(enum freq_qos_req_type type)
{
        int max_state, turbo_max, freq, i, perf_pct;
        struct freq_qos_request *req;
        struct cpufreq_policy *policy;

        for_each_possible_cpu(i) {
                struct cpudata *cpu = all_cpu_data[i];

                policy = cpufreq_cpu_get(i);
                if (!policy)
                        continue;

                req = policy->driver_data;
                cpufreq_cpu_put(policy);

                if (!req)
                        continue;

                if (hwp_active)
                        intel_pstate_get_hwp_max(i, &turbo_max, &max_state);
                else
                        turbo_max = cpu->pstate.turbo_pstate;

                if (type == FREQ_QOS_MIN) {
                        perf_pct = global.min_perf_pct;
                } else {
                        req++;
                        perf_pct = global.max_perf_pct;
                }

                freq = DIV_ROUND_UP(turbo_max * perf_pct, 100);
                freq *= cpu->pstate.scaling;

                if (freq_qos_update_request(req, freq) < 0)
                        pr_warn("Failed to update freq constraint: CPU%d\n", i);
        }
}

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

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

        mutex_lock(&intel_pstate_driver_lock);

        if (!intel_pstate_driver) {
                mutex_unlock(&intel_pstate_driver_lock);
                return -EAGAIN;
        }

        mutex_lock(&intel_pstate_limits_lock);

        global.max_perf_pct = clamp_t(int, input, global.min_perf_pct, 100);

        mutex_unlock(&intel_pstate_limits_lock);

        if (intel_pstate_driver == &intel_pstate)
                intel_pstate_update_policies();
        else
                update_qos_request(FREQ_QOS_MAX);

        mutex_unlock(&intel_pstate_driver_lock);

        return count;
}

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

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

        mutex_lock(&intel_pstate_driver_lock);

        if (!intel_pstate_driver) {
                mutex_unlock(&intel_pstate_driver_lock);
                return -EAGAIN;
        }

        mutex_lock(&intel_pstate_limits_lock);

        global.min_perf_pct = clamp_t(int, input,
                                      min_perf_pct_min(), global.max_perf_pct);

        mutex_unlock(&intel_pstate_limits_lock);

        if (intel_pstate_driver == &intel_pstate)
                intel_pstate_update_policies();
        else
                update_qos_request(FREQ_QOS_MIN);

        mutex_unlock(&intel_pstate_driver_lock);

        return count;
}

static ssize_t show_hwp_dynamic_boost(struct kobject *kobj,
                                struct kobj_attribute *attr, char *buf)
{
        return sprintf(buf, "%u\n", hwp_boost);
}

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

        ret = kstrtouint(buf, 10, &input);
        if (ret)
                return ret;

        mutex_lock(&intel_pstate_driver_lock);
        hwp_boost = !!input;
        intel_pstate_update_policies();
        mutex_unlock(&intel_pstate_driver_lock);

        return count;
}

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

define_one_global_rw(status);
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);
define_one_global_rw(hwp_dynamic_boost);

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

static const 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);
        if (WARN_ON(!intel_pstate_kobject))
                return;

        rc = sysfs_create_group(intel_pstate_kobject, &intel_pstate_attr_group);
        if (WARN_ON(rc))
                return;

        /*
         * If per cpu limits are enforced there are no global limits, so
         * return without creating max/min_perf_pct attributes
         */
        if (per_cpu_limits)
                return;

        rc = sysfs_create_file(intel_pstate_kobject, &max_perf_pct.attr);
        WARN_ON(rc);

        rc = sysfs_create_file(intel_pstate_kobject, &min_perf_pct.attr);
        WARN_ON(rc);

        if (hwp_active) {
                rc = sysfs_create_file(intel_pstate_kobject,
                                       &hwp_dynamic_boost.attr);
                WARN_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 (boot_cpu_has(X86_FEATURE_HWP_NOTIFY))
                wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_INTERRUPT, 0x00);

        wrmsrl_on_cpu(cpudata->cpu, MSR_PM_ENABLE, 0x1);
        cpudata->epp_policy = 0;
        if (cpudata->epp_default == -EINVAL)
                cpudata->epp_default = intel_pstate_get_epp(cpudata, 0);
}

#define MSR_IA32_POWER_CTL_BIT_EE       19

/* Disable energy efficiency optimization */
static void intel_pstate_disable_ee(int cpu)
{
        u64 power_ctl;
        int ret;

        ret = rdmsrl_on_cpu(cpu, MSR_IA32_POWER_CTL, &power_ctl);
        if (ret)
                return;

        if (!(power_ctl & BIT(MSR_IA32_POWER_CTL_BIT_EE))) {
                pr_info("Disabling energy efficiency optimization\n");
                power_ctl |= BIT(MSR_IA32_POWER_CTL_BIT_EE);
                wrmsrl_on_cpu(cpu, MSR_IA32_POWER_CTL, power_ctl);
        }
}

static int atom_get_min_pstate(void)
{
        u64 value;

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

static int atom_get_max_pstate(void)
{
        u64 value;

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

static int atom_get_turbo_pstate(void)
{
        u64 value;

        rdmsrl(MSR_ATOM_CORE_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 (global.no_turbo && !global.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(MSR_ATOM_CORE_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(MSR_ATOM_CORE_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_tdp_ratio(u64 plat_info)
{
        /* Check how many TDP levels present */
        if (plat_info & 0x600000000) {
                u64 tdp_ctrl;
                u64 tdp_ratio;
                int tdp_msr;
                int err;

                /* Get the TDP level (0, 1, 2) to get ratios */
                err = rdmsrl_safe(MSR_CONFIG_TDP_CONTROL, &tdp_ctrl);
                if (err)
                        return err;

                /* TDP MSR are continuous starting at 0x648 */
                tdp_msr = MSR_CONFIG_TDP_NOMINAL + (tdp_ctrl & 0x03);
                err = rdmsrl_safe(tdp_msr, &tdp_ratio);
                if (err)
                        return err;

                /* For level 1 and 2, bits[23:16] contain the ratio */
                if (tdp_ctrl & 0x03)
                        tdp_ratio >>= 16;

                tdp_ratio &= 0xff; /* ratios are only 8 bits long */
                pr_debug("tdp_ratio %x\n", (int)tdp_ratio);

                return (int)tdp_ratio;
        }

        return -ENXIO;
}

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

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

        tdp_ratio = core_get_tdp_ratio(plat_info);
        if (tdp_ratio <= 0)
                return max_pstate;

        if (hwp_active) {
                /* Turbo activation ratio is not used on HWP platforms */
                return tdp_ratio;
        }

        err = rdmsrl_safe(MSR_TURBO_ACTIVATION_RATIO, &tar);
        if (!err) {
                int tar_levels;

                /* Do some sanity checking for safety */
                tar_levels = tar & 0xff;
                if (tdp_ratio - 1 == tar_levels) {
                        max_pstate = tar_levels;
                        pr_debug("max_pstate=TAC %x\n", max_pstate);
                }
        }

        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 (global.no_turbo && !global.turbo_disabled)
                val |= (u64)1 << 32;

        return val;
}

static int knl_get_aperf_mperf_shift(void)
{
        return 10;
}

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 void intel_pstate_set_pstate(struct cpudata *cpu, int 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_set_min_pstate(struct cpudata *cpu)
{
        intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
}

static void intel_pstate_max_within_limits(struct cpudata *cpu)
{
        int pstate = max(cpu->pstate.min_pstate, cpu->max_perf_ratio);

        update_turbo_state();
        intel_pstate_set_pstate(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();
        cpu->pstate.max_freq = cpu->pstate.max_pstate * cpu->pstate.scaling;

        if (hwp_active && !hwp_mode_bdw) {
                unsigned int phy_max, current_max;

                intel_pstate_get_hwp_max(cpu->cpu, &phy_max, &current_max);
                cpu->pstate.turbo_freq = phy_max * cpu->pstate.scaling;
        } else {
                cpu->pstate.turbo_freq = cpu->pstate.turbo_pstate * cpu->pstate.scaling;
        }

        if (pstate_funcs.get_aperf_mperf_shift)
                cpu->aperf_mperf_shift = pstate_funcs.get_aperf_mperf_shift();

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

        intel_pstate_set_min_pstate(cpu);
}

/*
 * Long hold time will keep high perf limits for long time,
 * which negatively impacts perf/watt for some workloads,
 * like specpower. 3ms is based on experiements on some
 * workoads.
 */
static int hwp_boost_hold_time_ns = 3 * NSEC_PER_MSEC;

static inline void intel_pstate_hwp_boost_up(struct cpudata *cpu)
{
        u64 hwp_req = READ_ONCE(cpu->hwp_req_cached);
        u32 max_limit = (hwp_req & 0xff00) >> 8;
        u32 min_limit = (hwp_req & 0xff);
        u32 boost_level1;

        /*
         * Cases to consider (User changes via sysfs or boot time):
         * If, P0 (Turbo max) = P1 (Guaranteed max) = min:
         *      No boost, return.
         * If, P0 (Turbo max) > P1 (Guaranteed max) = min:
         *     Should result in one level boost only for P0.
         * If, P0 (Turbo max) = P1 (Guaranteed max) > min:
         *     Should result in two level boost:
         *         (min + p1)/2 and P1.
         * If, P0 (Turbo max) > P1 (Guaranteed max) > min:
         *     Should result in three level boost:
         *        (min + p1)/2, P1 and P0.
         */

        /* If max and min are equal or already at max, nothing to boost */
        if (max_limit == min_limit || cpu->hwp_boost_min >= max_limit)
                return;

        if (!cpu->hwp_boost_min)
                cpu->hwp_boost_min = min_limit;

        /* level at half way mark between min and guranteed */
        boost_level1 = (HWP_GUARANTEED_PERF(cpu->hwp_cap_cached) + min_limit) >> 1;

        if (cpu->hwp_boost_min < boost_level1)
                cpu->hwp_boost_min = boost_level1;
        else if (cpu->hwp_boost_min < HWP_GUARANTEED_PERF(cpu->hwp_cap_cached))
                cpu->hwp_boost_min = HWP_GUARANTEED_PERF(cpu->hwp_cap_cached);
        else if (cpu->hwp_boost_min == HWP_GUARANTEED_PERF(cpu->hwp_cap_cached) &&
                 max_limit != HWP_GUARANTEED_PERF(cpu->hwp_cap_cached))
                cpu->hwp_boost_min = max_limit;
        else
                return;

        hwp_req = (hwp_req & ~GENMASK_ULL(7, 0)) | cpu->hwp_boost_min;
        wrmsrl(MSR_HWP_REQUEST, hwp_req);
        cpu->last_update = cpu->sample.time;
}

static inline void intel_pstate_hwp_boost_down(struct cpudata *cpu)
{
        if (cpu->hwp_boost_min) {
                bool expired;

                /* Check if we are idle for hold time to boost down */
                expired = time_after64(cpu->sample.time, cpu->last_update +
                                       hwp_boost_hold_time_ns);
                if (expired) {
                        wrmsrl(MSR_HWP_REQUEST, cpu->hwp_req_cached);
                        cpu->hwp_boost_min = 0;
                }
        }
        cpu->last_update = cpu->sample.time;
}

static inline void intel_pstate_update_util_hwp_local(struct cpudata *cpu,
                                                      u64 time)
{
        cpu->sample.time = time;

        if (cpu->sched_flags & SCHED_CPUFREQ_IOWAIT) {
                bool do_io = false;

                cpu->sched_flags = 0;
                /*
                 * Set iowait_boost flag and update time. Since IO WAIT flag
                 * is set all the time, we can't just conclude that there is
                 * some IO bound activity is scheduled on this CPU with just
                 * one occurrence. If we receive at least two in two
                 * consecutive ticks, then we treat as boost candidate.
                 */
                if (time_before64(time, cpu->last_io_update + 2 * TICK_NSEC))
                        do_io = true;

                cpu->last_io_update = time;

                if (do_io)
                        intel_pstate_hwp_boost_up(cpu);

        } else {
                intel_pstate_hwp_boost_down(cpu);
        }
}

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

        cpu->sched_flags |= flags;

        if (smp_processor_id() == cpu->cpu)
                intel_pstate_update_util_hwp_local(cpu, time);
}

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.
         */
        if (cpu->last_sample_time) {
                intel_pstate_calc_avg_perf(cpu);
                return true;
        }
        return false;
}

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

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

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

        if (busy_frac < cpu->iowait_boost)
                busy_frac = cpu->iowait_boost;

        sample->busy_scaled = busy_frac * 100;

        target = global.no_turbo || global.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 int intel_pstate_prepare_request(struct cpudata *cpu, int pstate)
{
        int min_pstate = max(cpu->pstate.min_pstate, cpu->min_perf_ratio);
        int max_pstate = max(min_pstate, cpu->max_perf_ratio);

        return clamp_t(int, pstate, min_pstate, max_pstate);
}

static void intel_pstate_update_pstate(struct cpudata *cpu, int pstate)
{
        if (pstate == cpu->pstate.current_pstate)
                return;

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

static void intel_pstate_adjust_pstate(struct cpudata *cpu)
{
        int from = cpu->pstate.current_pstate;
        struct sample *sample;
        int target_pstate;

        update_turbo_state();

        target_pstate = get_target_pstate(cpu);
        target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
        trace_cpu_frequency(target_pstate * cpu->pstate.scaling, cpu->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;

        /* Don't allow remote callbacks */
        if (smp_processor_id() != cpu->cpu)
                return;

        delta_ns = time - cpu->last_update;
        if (flags & SCHED_CPUFREQ_IOWAIT) {
                /* Start over if the CPU may have been idle. */
                if (delta_ns > TICK_NSEC) {
                        cpu->iowait_boost = ONE_EIGHTH_FP;
                } else if (cpu->iowait_boost >= ONE_EIGHTH_FP) {
                        cpu->iowait_boost <<= 1;
                        if (cpu->iowait_boost > int_tofp(1))
                                cpu->iowait_boost = int_tofp(1);
                } else {
                        cpu->iowait_boost = ONE_EIGHTH_FP;
                }
        } else if (cpu->iowait_boost) {
                /* Clear iowait_boost if the CPU may have been idle. */
                if (delta_ns > TICK_NSEC)
                        cpu->iowait_boost = 0;
                else
                        cpu->iowait_boost >>= 1;
        }
        cpu->last_update = time;
        delta_ns = time - cpu->sample.time;
        if ((s64)delta_ns < INTEL_PSTATE_SAMPLING_INTERVAL)
                return;

        if (intel_pstate_sample(cpu, time))
                intel_pstate_adjust_pstate(cpu);
}

static struct pstate_funcs core_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,
};

static const struct pstate_funcs silvermont_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,
};

static const struct pstate_funcs airmont_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,
};

static const struct pstate_funcs knl_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_aperf_mperf_shift = knl_get_aperf_mperf_shift,
        .get_scaling = core_get_scaling,
        .get_val = core_get_val,
};

#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_funcs),
        ICPU(INTEL_FAM6_SANDYBRIDGE_X,          core_funcs),
        ICPU(INTEL_FAM6_ATOM_SILVERMONT,        silvermont_funcs),
        ICPU(INTEL_FAM6_IVYBRIDGE,              core_funcs),
        ICPU(INTEL_FAM6_HASWELL,                core_funcs),
        ICPU(INTEL_FAM6_BROADWELL,              core_funcs),
        ICPU(INTEL_FAM6_IVYBRIDGE_X,            core_funcs),
        ICPU(INTEL_FAM6_HASWELL_X,              core_funcs),
        ICPU(INTEL_FAM6_HASWELL_L,              core_funcs),
        ICPU(INTEL_FAM6_HASWELL_G,              core_funcs),
        ICPU(INTEL_FAM6_BROADWELL_G,            core_funcs),
        ICPU(INTEL_FAM6_ATOM_AIRMONT,           airmont_funcs),
        ICPU(INTEL_FAM6_SKYLAKE_L,              core_funcs),
        ICPU(INTEL_FAM6_BROADWELL_X,            core_funcs),
        ICPU(INTEL_FAM6_SKYLAKE,                core_funcs),
        ICPU(INTEL_FAM6_BROADWELL_D,            core_funcs),
        ICPU(INTEL_FAM6_XEON_PHI_KNL,           knl_funcs),
        ICPU(INTEL_FAM6_XEON_PHI_KNM,           knl_funcs),
        ICPU(INTEL_FAM6_ATOM_GOLDMONT,          core_funcs),
        ICPU(INTEL_FAM6_ATOM_GOLDMONT_PLUS,     core_funcs),
        ICPU(INTEL_FAM6_SKYLAKE_X,              core_funcs),
        {}
};
MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);

static const struct x86_cpu_id intel_pstate_cpu_oob_ids[] __initconst = {
        ICPU(INTEL_FAM6_BROADWELL_D, core_funcs),
        ICPU(INTEL_FAM6_BROADWELL_X, core_funcs),
        ICPU(INTEL_FAM6_SKYLAKE_X, core_funcs),
        {}
};

static const struct x86_cpu_id intel_pstate_cpu_ee_disable_ids[] = {
        ICPU(INTEL_FAM6_KABYLAKE, core_funcs),
        {}
};

static const struct x86_cpu_id intel_pstate_hwp_boost_ids[] = {
        ICPU(INTEL_FAM6_SKYLAKE_X, core_funcs),
        ICPU(INTEL_FAM6_SKYLAKE, core_funcs),
        {}
};

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

        cpu = all_cpu_data[cpunum];

        if (!cpu) {
                cpu = kzalloc(sizeof(*cpu), GFP_KERNEL);
                if (!cpu)
                        return -ENOMEM;

                all_cpu_data[cpunum] = cpu;

                cpu->epp_default = -EINVAL;
                cpu->epp_powersave = -EINVAL;
                cpu->epp_saved = -EINVAL;
        }

        cpu = all_cpu_data[cpunum];

        cpu->cpu = cpunum;

        if (hwp_active) {
                const struct x86_cpu_id *id;

                id = x86_match_cpu(intel_pstate_cpu_ee_disable_ids);
                if (id)
                        intel_pstate_disable_ee(cpunum);

                intel_pstate_hwp_enable(cpu);

                id = x86_match_cpu(intel_pstate_hwp_boost_ids);
                if (id && intel_pstate_acpi_pm_profile_server())
                        hwp_boost = true;
        }

        intel_pstate_get_cpu_pstates(cpu);

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

        return 0;
}

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

        if (hwp_active && !hwp_boost)
                return;

        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,
                                     (hwp_active ?
                                      intel_pstate_update_util_hwp :
                                      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_rcu();
}

static int intel_pstate_get_max_freq(struct cpudata *cpu)
{
        return global.turbo_disabled || global.no_turbo ?
                        cpu->pstate.max_freq : cpu->pstate.turbo_freq;
}

static void intel_pstate_update_perf_limits(struct cpudata *cpu,
                                            unsigned int policy_min,
                                            unsigned int policy_max)
{
        int max_freq = intel_pstate_get_max_freq(cpu);
        int32_t max_policy_perf, min_policy_perf;
        int max_state, turbo_max;

        /*
         * HWP needs some special consideration, because on BDX the
         * HWP_REQUEST uses abstract value to represent performance
         * rather than pure ratios.
         */
        if (hwp_active) {
                intel_pstate_get_hwp_max(cpu->cpu, &turbo_max, &max_state);
        } else {
                max_state = global.no_turbo || global.turbo_disabled ?
                        cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
                turbo_max = cpu->pstate.turbo_pstate;
        }

        max_policy_perf = max_state * policy_max / max_freq;
        if (policy_max == policy_min) {
                min_policy_perf = max_policy_perf;
        } else {
                min_policy_perf = max_state * policy_min / max_freq;
                min_policy_perf = clamp_t(int32_t, min_policy_perf,
                                          0, max_policy_perf);
        }

        pr_debug("cpu:%d max_state %d min_policy_perf:%d max_policy_perf:%d\n",
                 cpu->cpu, max_state, min_policy_perf, max_policy_perf);

        /* Normalize user input to [min_perf, max_perf] */
        if (per_cpu_limits) {
                cpu->min_perf_ratio = min_policy_perf;
                cpu->max_perf_ratio = max_policy_perf;
        } else {
                int32_t global_min, global_max;

                /* Global limits are in percent of the maximum turbo P-state. */
                global_max = DIV_ROUND_UP(turbo_max * global.max_perf_pct, 100);
                global_min = DIV_ROUND_UP(turbo_max * global.min_perf_pct, 100);
                global_min = clamp_t(int32_t, global_min, 0, global_max);

                pr_debug("cpu:%d global_min:%d global_max:%d\n", cpu->cpu,
                         global_min, global_max);

                cpu->min_perf_ratio = max(min_policy_perf, global_min);
                cpu->min_perf_ratio = min(cpu->min_perf_ratio, max_policy_perf);
                cpu->max_perf_ratio = min(max_policy_perf, global_max);
                cpu->max_perf_ratio = max(min_policy_perf, cpu->max_perf_ratio);

                /* Make sure min_perf <= max_perf */
                cpu->min_perf_ratio = min(cpu->min_perf_ratio,
                                          cpu->max_perf_ratio);

        }
        pr_debug("cpu:%d max_perf_ratio:%d min_perf_ratio:%d\n", cpu->cpu,
                 cpu->max_perf_ratio,
                 cpu->min_perf_ratio);
}

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[policy->cpu];
        cpu->policy = policy->policy;

        mutex_lock(&intel_pstate_limits_lock);

        intel_pstate_update_perf_limits(cpu, policy->min, policy->max);

        if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE) {
                /*
                 * NOHZ_FULL CPUs need this as the governor callback may not
                 * be invoked on them.
                 */
                intel_pstate_clear_update_util_hook(policy->cpu);
                intel_pstate_max_within_limits(cpu);
        } else {
                intel_pstate_set_update_util_hook(policy->cpu);
        }

        if (hwp_active) {
                /*
                 * When hwp_boost was active before and dynamically it
                 * was turned off, in that case we need to clear the
                 * update util hook.
                 */
                if (!hwp_boost)
                        intel_pstate_clear_update_util_hook(policy->cpu);
                intel_pstate_hwp_set(policy->cpu);
        }

        mutex_unlock(&intel_pstate_limits_lock);

        return 0;
}

static void intel_pstate_adjust_policy_max(struct cpudata *cpu,
                                           struct cpufreq_policy_data *policy)
{
        if (!hwp_active &&
            cpu->pstate.max_pstate_physical > cpu->pstate.max_pstate &&
            policy->max < policy->cpuinfo.max_freq &&
            policy->max > cpu->pstate.max_freq) {
                pr_debug("policy->max > max non turbo frequency\n");
                policy->max = policy->cpuinfo.max_freq;
        }
}

static int intel_pstate_verify_policy(struct cpufreq_policy_data *policy)
{
        struct cpudata *cpu = all_cpu_data[policy->cpu];

        update_turbo_state();
        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
                                     intel_pstate_get_max_freq(cpu));

        intel_pstate_adjust_policy_max(cpu, policy);

        return 0;
}

static void intel_cpufreq_stop_cpu(struct cpufreq_policy *policy)
{
        intel_pstate_set_min_pstate(all_cpu_data[policy->cpu]);
}

static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
{
        pr_debug("CPU %d exiting\n", policy->cpu);

        intel_pstate_clear_update_util_hook(policy->cpu);
        if (hwp_active) {
                intel_pstate_hwp_save_state(policy);
                intel_pstate_hwp_force_min_perf(policy->cpu);
        } else {
                intel_cpufreq_stop_cpu(policy);
        }
}

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

        policy->fast_switch_possible = false;

        return 0;
}

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];

        cpu->max_perf_ratio = 0xFF;
        cpu->min_perf_ratio = 0;

        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();
        global.turbo_disabled_mf = global.turbo_disabled;
        policy->cpuinfo.max_freq = global.turbo_disabled ?
                        cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
        policy->cpuinfo.max_freq *= cpu->pstate.scaling;

        if (hwp_active) {
                unsigned int max_freq;

                max_freq = global.turbo_disabled ?
                        cpu->pstate.max_freq : cpu->pstate.turbo_freq;
                if (max_freq < policy->cpuinfo.max_freq)
                        policy->cpuinfo.max_freq = max_freq;
        }

        intel_pstate_init_acpi_perf_limits(policy);

        policy->fast_switch_possible = true;

        return 0;
}

static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
{
        int ret = __intel_pstate_cpu_init(policy);

        if (ret)
                return ret;

        if (IS_ENABLED(CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE))
                policy->policy = CPUFREQ_POLICY_PERFORMANCE;
        else
                policy->policy = CPUFREQ_POLICY_POWERSAVE;

        return 0;
}

static struct cpufreq_driver intel_pstate = {
        .flags          = CPUFREQ_CONST_LOOPS,
        .verify         = intel_pstate_verify_policy,
        .setpolicy      = intel_pstate_set_policy,
        .suspend        = intel_pstate_hwp_save_state,
        .resume         = intel_pstate_resume,
        .init           = intel_pstate_cpu_init,
        .exit           = intel_pstate_cpu_exit,
        .stop_cpu       = intel_pstate_stop_cpu,
        .update_limits  = intel_pstate_update_limits,
        .name           = "intel_pstate",
};

static int intel_cpufreq_verify_policy(struct cpufreq_policy_data *policy)
{
        struct cpudata *cpu = all_cpu_data[policy->cpu];

        update_turbo_state();
        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
                                     intel_pstate_get_max_freq(cpu));

        intel_pstate_adjust_policy_max(cpu, policy);

        intel_pstate_update_perf_limits(cpu, policy->min, policy->max);

        return 0;
}

/* Use of trace in passive mode:
 *
 * In passive mode the trace core_busy field (also known as the
 * performance field, and lablelled as such on the graphs; also known as
 * core_avg_perf) is not needed and so is re-assigned to indicate if the
 * driver call was via the normal or fast switch path. Various graphs
 * output from the intel_pstate_tracer.py utility that include core_busy
 * (or performance or core_avg_perf) have a fixed y-axis from 0 to 100%,
 * so we use 10 to indicate the the normal path through the driver, and
 * 90 to indicate the fast switch path through the driver.
 * The scaled_busy field is not used, and is set to 0.
 */

#define INTEL_PSTATE_TRACE_TARGET 10
#define INTEL_PSTATE_TRACE_FAST_SWITCH 90

static void intel_cpufreq_trace(struct cpudata *cpu, unsigned int trace_type, int old_pstate)
{
        struct sample *sample;

        if (!trace_pstate_sample_enabled())
                return;

        if (!intel_pstate_sample(cpu, ktime_get()))
                return;

        sample = &cpu->sample;
        trace_pstate_sample(trace_type,
                0,
                old_pstate,
                cpu->pstate.current_pstate,
                sample->mperf,
                sample->aperf,
                sample->tsc,
                get_avg_frequency(cpu),
                fp_toint(cpu->iowait_boost * 100));
}

static int intel_cpufreq_target(struct cpufreq_policy *policy,
                                unsigned int target_freq,
                                unsigned int relation)
{
        struct cpudata *cpu = all_cpu_data[policy->cpu];
        struct cpufreq_freqs freqs;
        int target_pstate, old_pstate;

        update_turbo_state();

        freqs.old = policy->cur;
        freqs.new = target_freq;

        cpufreq_freq_transition_begin(policy, &freqs);
        switch (relation) {
        case CPUFREQ_RELATION_L:
                target_pstate = DIV_ROUND_UP(freqs.new, cpu->pstate.scaling);
                break;
        case CPUFREQ_RELATION_H:
                target_pstate = freqs.new / cpu->pstate.scaling;
                break;
        default:
                target_pstate = DIV_ROUND_CLOSEST(freqs.new, cpu->pstate.scaling);
                break;
        }
        target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
        old_pstate = cpu->pstate.current_pstate;
        if (target_pstate != cpu->pstate.current_pstate) {
                cpu->pstate.current_pstate = target_pstate;
                wrmsrl_on_cpu(policy->cpu, MSR_IA32_PERF_CTL,
                              pstate_funcs.get_val(cpu, target_pstate));
        }
        freqs.new = target_pstate * cpu->pstate.scaling;
        intel_cpufreq_trace(cpu, INTEL_PSTATE_TRACE_TARGET, old_pstate);
        cpufreq_freq_transition_end(policy, &freqs, false);

        return 0;
}

static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy,
                                              unsigned int target_freq)
{
        struct cpudata *cpu = all_cpu_data[policy->cpu];
        int target_pstate, old_pstate;

        update_turbo_state();

        target_pstate = DIV_ROUND_UP(target_freq, cpu->pstate.scaling);
        target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
        old_pstate = cpu->pstate.current_pstate;
        intel_pstate_update_pstate(cpu, target_pstate);
        intel_cpufreq_trace(cpu, INTEL_PSTATE_TRACE_FAST_SWITCH, old_pstate);
        return target_pstate * cpu->pstate.scaling;
}

static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
        int max_state, turbo_max, min_freq, max_freq, ret;
        struct freq_qos_request *req;
        struct cpudata *cpu;
        struct device *dev;

        dev = get_cpu_device(policy->cpu);
        if (!dev)
                return -ENODEV;

        ret = __intel_pstate_cpu_init(policy);
        if (ret)
                return ret;

        policy->cpuinfo.transition_latency = INTEL_CPUFREQ_TRANSITION_LATENCY;
        policy->transition_delay_us = INTEL_CPUFREQ_TRANSITION_DELAY;
        /* This reflects the intel_pstate_get_cpu_pstates() setting. */
        policy->cur = policy->cpuinfo.min_freq;

        req = kcalloc(2, sizeof(*req), GFP_KERNEL);
        if (!req) {
                ret = -ENOMEM;
                goto pstate_exit;
        }

        cpu = all_cpu_data[policy->cpu];

        if (hwp_active)
                intel_pstate_get_hwp_max(policy->cpu, &turbo_max, &max_state);
        else
                turbo_max = cpu->pstate.turbo_pstate;

        min_freq = DIV_ROUND_UP(turbo_max * global.min_perf_pct, 100);
        min_freq *= cpu->pstate.scaling;
        max_freq = DIV_ROUND_UP(turbo_max * global.max_perf_pct, 100);
        max_freq *= cpu->pstate.scaling;

        ret = freq_qos_add_request(&policy->constraints, req, FREQ_QOS_MIN,
                                   min_freq);
        if (ret < 0) {
                dev_err(dev, "Failed to add min-freq constraint (%d)\n", ret);
                goto free_req;
        }

        ret = freq_qos_add_request(&policy->constraints, req + 1, FREQ_QOS_MAX,
                                   max_freq);
        if (ret < 0) {
                dev_err(dev, "Failed to add max-freq constraint (%d)\n", ret);
                goto remove_min_req;
        }

        policy->driver_data = req;

        return 0;

remove_min_req:
        freq_qos_remove_request(req);
free_req:
        kfree(req);
pstate_exit:
        intel_pstate_exit_perf_limits(policy);

        return ret;
}

static int intel_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
        struct freq_qos_request *req;

        req = policy->driver_data;

        freq_qos_remove_request(req + 1);
        freq_qos_remove_request(req);
        kfree(req);

        return intel_pstate_cpu_exit(policy);
}

static struct cpufreq_driver intel_cpufreq = {
        .flags          = CPUFREQ_CONST_LOOPS,
        .verify         = intel_cpufreq_verify_policy,
        .target         = intel_cpufreq_target,
        .fast_switch    = intel_cpufreq_fast_switch,
        .init           = intel_cpufreq_cpu_init,
        .exit           = intel_cpufreq_cpu_exit,
        .stop_cpu       = intel_cpufreq_stop_cpu,
        .update_limits  = intel_pstate_update_limits,
        .name           = "intel_cpufreq",
};

static struct cpufreq_driver *default_driver = &intel_pstate;

static void intel_pstate_driver_cleanup(void)
{
        unsigned int cpu;

        get_online_cpus();
        for_each_online_cpu(cpu) {
                if (all_cpu_data[cpu]) {
                        if (intel_pstate_driver == &intel_pstate)
                                intel_pstate_clear_update_util_hook(cpu);

                        kfree(all_cpu_data[cpu]);
                        all_cpu_data[cpu] = NULL;
                }
        }
        put_online_cpus();
        intel_pstate_driver = NULL;
}

static int intel_pstate_register_driver(struct cpufreq_driver *driver)
{
        int ret;

        memset(&global, 0, sizeof(global));
        global.max_perf_pct = 100;

        intel_pstate_driver = driver;
        ret = cpufreq_register_driver(intel_pstate_driver);
        if (ret) {
                intel_pstate_driver_cleanup();
                return ret;
        }

        global.min_perf_pct = min_perf_pct_min();

        return 0;
}

static int intel_pstate_unregister_driver(void)
{
        if (hwp_active)
                return -EBUSY;

        cpufreq_unregister_driver(intel_pstate_driver);
        intel_pstate_driver_cleanup();

        return 0;
}

static ssize_t intel_pstate_show_status(char *buf)
{
        if (!intel_pstate_driver)
                return sprintf(buf, "off\n");

        return sprintf(buf, "%s\n", intel_pstate_driver == &intel_pstate ?
                                        "active" : "passive");
}

static int intel_pstate_update_status(const char *buf, size_t size)
{
        int ret;

        if (size == 3 && !strncmp(buf, "off", size))
                return intel_pstate_driver ?
                        intel_pstate_unregister_driver() : -EINVAL;

        if (size == 6 && !strncmp(buf, "active", size)) {
                if (intel_pstate_driver) {
                        if (intel_pstate_driver == &intel_pstate)
                                return 0;

                        ret = intel_pstate_unregister_driver();
                        if (ret)
                                return ret;
                }

                return intel_pstate_register_driver(&intel_pstate);
        }

        if (size == 7 && !strncmp(buf, "passive", size)) {
                if (intel_pstate_driver) {
                        if (intel_pstate_driver == &intel_cpufreq)
                                return 0;

                        ret = intel_pstate_unregister_driver();
                        if (ret)
                                return ret;
                }

                return intel_pstate_register_driver(&intel_cpufreq);
        }

        return -EINVAL;
}

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_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_aperf_mperf_shift = funcs->get_aperf_mperf_shift;
}

#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);
        }

        pr_debug("ACPI _PSS not found\n");
        return true;
}

static bool __init intel_pstate_no_acpi_pcch(void)
{
        acpi_status status;
        acpi_handle handle;

        status = acpi_get_handle(NULL, "\\_SB", &handle);
        if (ACPI_FAILURE(status))
                goto not_found;

        if (acpi_has_method(handle, "PCCH"))
                return false;

not_found:
        pr_debug("ACPI PCCH not found\n");
        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;
        }
        pr_debug("ACPI _PPC not found\n");
        return false;
}

enum {
        PSS,
        PPC,
};

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

static bool __init intel_pstate_platform_pwr_mgmt_exists(void)
{
        const struct x86_cpu_id *id;
        u64 misc_pwr;
        int idx;

        id = x86_match_cpu(intel_pstate_cpu_oob_ids);
        if (id) {
                rdmsrl(MSR_MISC_PWR_MGMT, misc_pwr);
                if (misc_pwr & (1 << 8)) {
                        pr_debug("Bit 8 in the MISC_PWR_MGMT MSR set\n");
                        return true;
                }
        }

        idx = acpi_match_platform_list(plat_info);
        if (idx < 0)
                return false;

        switch (plat_info[idx].data) {
        case PSS:
                if (!intel_pstate_no_acpi_pss())
                        return false;

                return intel_pstate_no_acpi_pcch();
        case PPC:
                return intel_pstate_has_acpi_ppc() && !force_load;
        }

        return false;
}

static void intel_pstate_request_control_from_smm(void)
{
        /*
         * It may be unsafe to request P-states control from SMM if _PPC support
         * has not been enabled.
         */
        if (acpi_ppc)
                acpi_processor_pstate_control();
}
#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; }
static inline void intel_pstate_request_control_from_smm(void) {}
#endif /* CONFIG_ACPI */

#define INTEL_PSTATE_HWP_BROADWELL      0x01

#define ICPU_HWP(model, hwp_mode) \
        { X86_VENDOR_INTEL, 6, model, X86_FEATURE_HWP, hwp_mode }

static const struct x86_cpu_id hwp_support_ids[] __initconst = {
        ICPU_HWP(INTEL_FAM6_BROADWELL_X, INTEL_PSTATE_HWP_BROADWELL),
        ICPU_HWP(INTEL_FAM6_BROADWELL_D, INTEL_PSTATE_HWP_BROADWELL),
        ICPU_HWP(X86_MODEL_ANY, 0),
        {}
};

static int __init intel_pstate_init(void)
{
        const struct x86_cpu_id *id;
        int rc;

        if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
                return -ENODEV;

        if (no_load)
                return -ENODEV;

        id = x86_match_cpu(hwp_support_ids);
        if (id) {
                copy_cpu_funcs(&core_funcs);
                if (!no_hwp) {
                        hwp_active++;
                        hwp_mode_bdw = id->driver_data;
                        intel_pstate.attr = hwp_cpufreq_attrs;
                        goto hwp_cpu_matched;
                }
        } else {
                id = x86_match_cpu(intel_pstate_cpu_ids);
                if (!id) {
                        pr_info("CPU model not supported\n");
                        return -ENODEV;
                }

                copy_cpu_funcs((struct pstate_funcs *)id->driver_data);
        }

        if (intel_pstate_msrs_not_valid()) {
                pr_info("Invalid MSRs\n");
                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()) {
                pr_info("P-states controlled by the platform\n");
                return -ENODEV;
        }

        if (!hwp_active && hwp_only)
                return -ENOTSUPP;

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

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

        intel_pstate_request_control_from_smm();

        intel_pstate_sysfs_expose_params();

        mutex_lock(&intel_pstate_driver_lock);
        rc = intel_pstate_register_driver(default_driver);
        mutex_unlock(&intel_pstate_driver_lock);
        if (rc)
                return rc;

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

        return 0;
}
device_initcall(intel_pstate_init);

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

        if (!strcmp(str, "disable")) {
                no_load = 1;
        } else if (!strcmp(str, "passive")) {
                pr_info("Passive mode enabled\n");
                default_driver = &intel_cpufreq;
                no_hwp = 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;
        if (!strcmp(str, "per_cpu_perf_limits"))
                per_cpu_limits = true;

#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");