/*
 * Intel Running Average Power Limit (RAPL) Driver
 * Copyright (c) 2013, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/bitmap.h>
#include <linux/delay.h>
#include <linux/sysfs.h>
#include <linux/cpu.h>
#include <linux/powercap.h>
#include <asm/iosf_mbi.h>

#include <asm/processor.h>
#include <asm/cpu_device_id.h>

/* bitmasks for RAPL MSRs, used by primitive access functions */
#define ENERGY_STATUS_MASK      0xffffffff

#define POWER_LIMIT1_MASK       0x7FFF
#define POWER_LIMIT1_ENABLE     BIT(15)
#define POWER_LIMIT1_CLAMP      BIT(16)

#define POWER_LIMIT2_MASK       (0x7FFFULL<<32)
#define POWER_LIMIT2_ENABLE     BIT_ULL(47)
#define POWER_LIMIT2_CLAMP      BIT_ULL(48)
#define POWER_PACKAGE_LOCK      BIT_ULL(63)
#define POWER_PP_LOCK           BIT(31)

#define TIME_WINDOW1_MASK       (0x7FULL<<17)
#define TIME_WINDOW2_MASK       (0x7FULL<<49)

#define POWER_UNIT_OFFSET       0
#define POWER_UNIT_MASK         0x0F

#define ENERGY_UNIT_OFFSET      0x08
#define ENERGY_UNIT_MASK        0x1F00

#define TIME_UNIT_OFFSET        0x10
#define TIME_UNIT_MASK          0xF0000

#define POWER_INFO_MAX_MASK     (0x7fffULL<<32)
#define POWER_INFO_MIN_MASK     (0x7fffULL<<16)
#define POWER_INFO_MAX_TIME_WIN_MASK     (0x3fULL<<48)
#define POWER_INFO_THERMAL_SPEC_MASK     0x7fff

#define PERF_STATUS_THROTTLE_TIME_MASK 0xffffffff
#define PP_POLICY_MASK         0x1F

/* Non HW constants */
#define RAPL_PRIMITIVE_DERIVED       BIT(1) /* not from raw data */
#define RAPL_PRIMITIVE_DUMMY         BIT(2)

#define TIME_WINDOW_MAX_MSEC 40000
#define TIME_WINDOW_MIN_MSEC 250
#define ENERGY_UNIT_SCALE    1000 /* scale from driver unit to powercap unit */
enum unit_type {
        ARBITRARY_UNIT, /* no translation */
        POWER_UNIT,
        ENERGY_UNIT,
        TIME_UNIT,
};

enum rapl_domain_type {
        RAPL_DOMAIN_PACKAGE, /* entire package/socket */
        RAPL_DOMAIN_PP0, /* core power plane */
        RAPL_DOMAIN_PP1, /* graphics uncore */
        RAPL_DOMAIN_DRAM,/* DRAM control_type */
        RAPL_DOMAIN_MAX,
};

enum rapl_domain_msr_id {
        RAPL_DOMAIN_MSR_LIMIT,
        RAPL_DOMAIN_MSR_STATUS,
        RAPL_DOMAIN_MSR_PERF,
        RAPL_DOMAIN_MSR_POLICY,
        RAPL_DOMAIN_MSR_INFO,
        RAPL_DOMAIN_MSR_MAX,
};

/* per domain data, some are optional */
enum rapl_primitives {
        ENERGY_COUNTER,
        POWER_LIMIT1,
        POWER_LIMIT2,
        FW_LOCK,

        PL1_ENABLE,  /* power limit 1, aka long term */
        PL1_CLAMP,   /* allow frequency to go below OS request */
        PL2_ENABLE,  /* power limit 2, aka short term, instantaneous */
        PL2_CLAMP,

        TIME_WINDOW1, /* long term */
        TIME_WINDOW2, /* short term */
        THERMAL_SPEC_POWER,
        MAX_POWER,

        MIN_POWER,
        MAX_TIME_WINDOW,
        THROTTLED_TIME,
        PRIORITY_LEVEL,

        /* below are not raw primitive data */
        AVERAGE_POWER,
        NR_RAPL_PRIMITIVES,
};

#define NR_RAW_PRIMITIVES (NR_RAPL_PRIMITIVES - 2)

/* Can be expanded to include events, etc.*/
struct rapl_domain_data {
        u64 primitives[NR_RAPL_PRIMITIVES];
        unsigned long timestamp;
};

struct msrl_action {
        u32 msr_no;
        u64 clear_mask;
        u64 set_mask;
        int err;
};

#define DOMAIN_STATE_INACTIVE           BIT(0)
#define DOMAIN_STATE_POWER_LIMIT_SET    BIT(1)
#define DOMAIN_STATE_BIOS_LOCKED        BIT(2)

#define NR_POWER_LIMITS (2)
struct rapl_power_limit {
        struct powercap_zone_constraint *constraint;
        int prim_id; /* primitive ID used to enable */
        struct rapl_domain *domain;
        const char *name;
};

static const char pl1_name[] = "long_term";
static const char pl2_name[] = "short_term";

struct rapl_package;
struct rapl_domain {
        const char *name;
        enum rapl_domain_type id;
        int msrs[RAPL_DOMAIN_MSR_MAX];
        struct powercap_zone power_zone;
        struct rapl_domain_data rdd;
        struct rapl_power_limit rpl[NR_POWER_LIMITS];
        u64 attr_map; /* track capabilities */
        unsigned int state;
        unsigned int domain_energy_unit;
        struct rapl_package *rp;
};
#define power_zone_to_rapl_domain(_zone) \
        container_of(_zone, struct rapl_domain, power_zone)


/* Each physical package contains multiple domains, these are the common
 * data across RAPL domains within a package.
 */
struct rapl_package {
        unsigned int id; /* physical package/socket id */
        unsigned int nr_domains;
        unsigned long domain_map; /* bit map of active domains */
        unsigned int power_unit;
        unsigned int energy_unit;
        unsigned int time_unit;
        struct rapl_domain *domains; /* array of domains, sized at runtime */
        struct powercap_zone *power_zone; /* keep track of parent zone */
        int nr_cpus; /* active cpus on the package, topology info is lost during
                      * cpu hotplug. so we have to track ourselves.
                      */
        unsigned long power_limit_irq; /* keep track of package power limit
                                        * notify interrupt enable status.
                                        */
        struct list_head plist;
        int lead_cpu; /* one active cpu per package for access */
};

struct rapl_defaults {
        u8 floor_freq_reg_addr;
        int (*check_unit)(struct rapl_package *rp, int cpu);
        void (*set_floor_freq)(struct rapl_domain *rd, bool mode);
        u64 (*compute_time_window)(struct rapl_package *rp, u64 val,
                                bool to_raw);
        unsigned int dram_domain_energy_unit;
};
static struct rapl_defaults *rapl_defaults;

/* Sideband MBI registers */
#define IOSF_CPU_POWER_BUDGET_CTL_BYT (0x2)
#define IOSF_CPU_POWER_BUDGET_CTL_TNG (0xdf)

#define PACKAGE_PLN_INT_SAVED   BIT(0)
#define MAX_PRIM_NAME (32)

/* per domain data. used to describe individual knobs such that access function
 * can be consolidated into one instead of many inline functions.
 */
struct rapl_primitive_info {
        const char *name;
        u64 mask;
        int shift;
        enum rapl_domain_msr_id id;
        enum unit_type unit;
        u32 flag;
};

#define PRIMITIVE_INFO_INIT(p, m, s, i, u, f) { \
                .name = #p,                     \
                .mask = m,                      \
                .shift = s,                     \
                .id = i,                        \
                .unit = u,                      \
                .flag = f                       \
        }

static void rapl_init_domains(struct rapl_package *rp);
static int rapl_read_data_raw(struct rapl_domain *rd,
                        enum rapl_primitives prim,
                        bool xlate, u64 *data);
static int rapl_write_data_raw(struct rapl_domain *rd,
                        enum rapl_primitives prim,
                        unsigned long long value);
static u64 rapl_unit_xlate(struct rapl_domain *rd,
                        enum unit_type type, u64 value,
                        int to_raw);
static void package_power_limit_irq_save(struct rapl_package *rp);

static LIST_HEAD(rapl_packages); /* guarded by CPU hotplug lock */

static const char * const rapl_domain_names[] = {
        "package",
        "core",
        "uncore",
        "dram",
};

static struct powercap_control_type *control_type; /* PowerCap Controller */

/* caller to ensure CPU hotplug lock is held */
static struct rapl_package *find_package_by_id(int id)
{
        struct rapl_package *rp;

        list_for_each_entry(rp, &rapl_packages, plist) {
                if (rp->id == id)
                        return rp;
        }

        return NULL;
}

/* caller must hold cpu hotplug lock */
static void rapl_cleanup_data(void)
{
        struct rapl_package *p, *tmp;

        list_for_each_entry_safe(p, tmp, &rapl_packages, plist) {
                kfree(p->domains);
                list_del(&p->plist);
                kfree(p);
        }
}

static int get_energy_counter(struct powercap_zone *power_zone, u64 *energy_raw)
{
        struct rapl_domain *rd;
        u64 energy_now;

        /* prevent CPU hotplug, make sure the RAPL domain does not go
         * away while reading the counter.
         */
        get_online_cpus();
        rd = power_zone_to_rapl_domain(power_zone);

        if (!rapl_read_data_raw(rd, ENERGY_COUNTER, true, &energy_now)) {
                *energy_raw = energy_now;
                put_online_cpus();

                return 0;
        }
        put_online_cpus();

        return -EIO;
}

static int get_max_energy_counter(struct powercap_zone *pcd_dev, u64 *energy)
{
        struct rapl_domain *rd = power_zone_to_rapl_domain(pcd_dev);

        *energy = rapl_unit_xlate(rd, ENERGY_UNIT, ENERGY_STATUS_MASK, 0);
        return 0;
}

static int release_zone(struct powercap_zone *power_zone)
{
        struct rapl_domain *rd = power_zone_to_rapl_domain(power_zone);
        struct rapl_package *rp = rd->rp;

        /* package zone is the last zone of a package, we can free
         * memory here since all children has been unregistered.
         */
        if (rd->id == RAPL_DOMAIN_PACKAGE) {
                kfree(rd);
                rp->domains = NULL;
        }

        return 0;

}

static int find_nr_power_limit(struct rapl_domain *rd)
{
        int i;

        for (i = 0; i < NR_POWER_LIMITS; i++) {
                if (rd->rpl[i].name == NULL)
                        break;
        }

        return i;
}

static int set_domain_enable(struct powercap_zone *power_zone, bool mode)
{
        struct rapl_domain *rd = power_zone_to_rapl_domain(power_zone);

        if (rd->state & DOMAIN_STATE_BIOS_LOCKED)
                return -EACCES;

        get_online_cpus();
        rapl_write_data_raw(rd, PL1_ENABLE, mode);
        if (rapl_defaults->set_floor_freq)
                rapl_defaults->set_floor_freq(rd, mode);
        put_online_cpus();

        return 0;
}

static int get_domain_enable(struct powercap_zone *power_zone, bool *mode)
{
        struct rapl_domain *rd = power_zone_to_rapl_domain(power_zone);
        u64 val;

        if (rd->state & DOMAIN_STATE_BIOS_LOCKED) {
                *mode = false;
                return 0;
        }
        get_online_cpus();
        if (rapl_read_data_raw(rd, PL1_ENABLE, true, &val)) {
                put_online_cpus();
                return -EIO;
        }
        *mode = val;
        put_online_cpus();

        return 0;
}

/* per RAPL domain ops, in the order of rapl_domain_type */
static const struct powercap_zone_ops zone_ops[] = {
        /* RAPL_DOMAIN_PACKAGE */
        {
                .get_energy_uj = get_energy_counter,
                .get_max_energy_range_uj = get_max_energy_counter,
                .release = release_zone,
                .set_enable = set_domain_enable,
                .get_enable = get_domain_enable,
        },
        /* RAPL_DOMAIN_PP0 */
        {
                .get_energy_uj = get_energy_counter,
                .get_max_energy_range_uj = get_max_energy_counter,
                .release = release_zone,
                .set_enable = set_domain_enable,
                .get_enable = get_domain_enable,
        },
        /* RAPL_DOMAIN_PP1 */
        {
                .get_energy_uj = get_energy_counter,
                .get_max_energy_range_uj = get_max_energy_counter,
                .release = release_zone,
                .set_enable = set_domain_enable,
                .get_enable = get_domain_enable,
        },
        /* RAPL_DOMAIN_DRAM */
        {
                .get_energy_uj = get_energy_counter,
                .get_max_energy_range_uj = get_max_energy_counter,
                .release = release_zone,
                .set_enable = set_domain_enable,
                .get_enable = get_domain_enable,
        },
};

static int set_power_limit(struct powercap_zone *power_zone, int id,
                        u64 power_limit)
{
        struct rapl_domain *rd;
        struct rapl_package *rp;
        int ret = 0;

        get_online_cpus();
        rd = power_zone_to_rapl_domain(power_zone);
        rp = rd->rp;

        if (rd->state & DOMAIN_STATE_BIOS_LOCKED) {
                dev_warn(&power_zone->dev, "%s locked by BIOS, monitoring only\n",
                        rd->name);
                ret = -EACCES;
                goto set_exit;
        }

        switch (rd->rpl[id].prim_id) {
        case PL1_ENABLE:
                rapl_write_data_raw(rd, POWER_LIMIT1, power_limit);
                break;
        case PL2_ENABLE:
                rapl_write_data_raw(rd, POWER_LIMIT2, power_limit);
                break;
        default:
                ret = -EINVAL;
        }
        if (!ret)
                package_power_limit_irq_save(rp);
set_exit:
        put_online_cpus();
        return ret;
}

static int get_current_power_limit(struct powercap_zone *power_zone, int id,
                                        u64 *data)
{
        struct rapl_domain *rd;
        u64 val;
        int prim;
        int ret = 0;

        get_online_cpus();
        rd = power_zone_to_rapl_domain(power_zone);
        switch (rd->rpl[id].prim_id) {
        case PL1_ENABLE:
                prim = POWER_LIMIT1;
                break;
        case PL2_ENABLE:
                prim = POWER_LIMIT2;
                break;
        default:
                put_online_cpus();
                return -EINVAL;
        }
        if (rapl_read_data_raw(rd, prim, true, &val))
                ret = -EIO;
        else
                *data = val;

        put_online_cpus();

        return ret;
}

static int set_time_window(struct powercap_zone *power_zone, int id,
                                                                u64 window)
{
        struct rapl_domain *rd;
        int ret = 0;

        get_online_cpus();
        rd = power_zone_to_rapl_domain(power_zone);
        switch (rd->rpl[id].prim_id) {
        case PL1_ENABLE:
                rapl_write_data_raw(rd, TIME_WINDOW1, window);
                break;
        case PL2_ENABLE:
                rapl_write_data_raw(rd, TIME_WINDOW2, window);
                break;
        default:
                ret = -EINVAL;
        }
        put_online_cpus();
        return ret;
}

static int get_time_window(struct powercap_zone *power_zone, int id, u64 *data)
{
        struct rapl_domain *rd;
        u64 val;
        int ret = 0;

        get_online_cpus();
        rd = power_zone_to_rapl_domain(power_zone);
        switch (rd->rpl[id].prim_id) {
        case PL1_ENABLE:
                ret = rapl_read_data_raw(rd, TIME_WINDOW1, true, &val);
                break;
        case PL2_ENABLE:
                ret = rapl_read_data_raw(rd, TIME_WINDOW2, true, &val);
                break;
        default:
                put_online_cpus();
                return -EINVAL;
        }
        if (!ret)
                *data = val;
        put_online_cpus();

        return ret;
}

static const char *get_constraint_name(struct powercap_zone *power_zone, int id)
{
        struct rapl_power_limit *rpl;
        struct rapl_domain *rd;

        rd = power_zone_to_rapl_domain(power_zone);
        rpl = (struct rapl_power_limit *) &rd->rpl[id];

        return rpl->name;
}


static int get_max_power(struct powercap_zone *power_zone, int id,
                                        u64 *data)
{
        struct rapl_domain *rd;
        u64 val;
        int prim;
        int ret = 0;

        get_online_cpus();
        rd = power_zone_to_rapl_domain(power_zone);
        switch (rd->rpl[id].prim_id) {
        case PL1_ENABLE:
                prim = THERMAL_SPEC_POWER;
                break;
        case PL2_ENABLE:
                prim = MAX_POWER;
                break;
        default:
                put_online_cpus();
                return -EINVAL;
        }
        if (rapl_read_data_raw(rd, prim, true, &val))
                ret = -EIO;
        else
                *data = val;

        put_online_cpus();

        return ret;
}

static const struct powercap_zone_constraint_ops constraint_ops = {
        .set_power_limit_uw = set_power_limit,
        .get_power_limit_uw = get_current_power_limit,
        .set_time_window_us = set_time_window,
        .get_time_window_us = get_time_window,
        .get_max_power_uw = get_max_power,
        .get_name = get_constraint_name,
};

/* called after domain detection and package level data are set */
static void rapl_init_domains(struct rapl_package *rp)
{
        int i;
        struct rapl_domain *rd = rp->domains;

        for (i = 0; i < RAPL_DOMAIN_MAX; i++) {
                unsigned int mask = rp->domain_map & (1 << i);
                switch (mask) {
                case BIT(RAPL_DOMAIN_PACKAGE):
                        rd->name = rapl_domain_names[RAPL_DOMAIN_PACKAGE];
                        rd->id = RAPL_DOMAIN_PACKAGE;
                        rd->msrs[0] = MSR_PKG_POWER_LIMIT;
                        rd->msrs[1] = MSR_PKG_ENERGY_STATUS;
                        rd->msrs[2] = MSR_PKG_PERF_STATUS;
                        rd->msrs[3] = 0;
                        rd->msrs[4] = MSR_PKG_POWER_INFO;
                        rd->rpl[0].prim_id = PL1_ENABLE;
                        rd->rpl[0].name = pl1_name;
                        rd->rpl[1].prim_id = PL2_ENABLE;
                        rd->rpl[1].name = pl2_name;
                        break;
                case BIT(RAPL_DOMAIN_PP0):
                        rd->name = rapl_domain_names[RAPL_DOMAIN_PP0];
                        rd->id = RAPL_DOMAIN_PP0;
                        rd->msrs[0] = MSR_PP0_POWER_LIMIT;
                        rd->msrs[1] = MSR_PP0_ENERGY_STATUS;
                        rd->msrs[2] = 0;
                        rd->msrs[3] = MSR_PP0_POLICY;
                        rd->msrs[4] = 0;
                        rd->rpl[0].prim_id = PL1_ENABLE;
                        rd->rpl[0].name = pl1_name;
                        break;
                case BIT(RAPL_DOMAIN_PP1):
                        rd->name = rapl_domain_names[RAPL_DOMAIN_PP1];
                        rd->id = RAPL_DOMAIN_PP1;
                        rd->msrs[0] = MSR_PP1_POWER_LIMIT;
                        rd->msrs[1] = MSR_PP1_ENERGY_STATUS;
                        rd->msrs[2] = 0;
                        rd->msrs[3] = MSR_PP1_POLICY;
                        rd->msrs[4] = 0;
                        rd->rpl[0].prim_id = PL1_ENABLE;
                        rd->rpl[0].name = pl1_name;
                        break;
                case BIT(RAPL_DOMAIN_DRAM):
                        rd->name = rapl_domain_names[RAPL_DOMAIN_DRAM];
                        rd->id = RAPL_DOMAIN_DRAM;
                        rd->msrs[0] = MSR_DRAM_POWER_LIMIT;
                        rd->msrs[1] = MSR_DRAM_ENERGY_STATUS;
                        rd->msrs[2] = MSR_DRAM_PERF_STATUS;
                        rd->msrs[3] = 0;
                        rd->msrs[4] = MSR_DRAM_POWER_INFO;
                        rd->rpl[0].prim_id = PL1_ENABLE;
                        rd->rpl[0].name = pl1_name;
                        rd->domain_energy_unit =
                                rapl_defaults->dram_domain_energy_unit;
                        if (rd->domain_energy_unit)
                                pr_info("DRAM domain energy unit %dpj\n",
                                        rd->domain_energy_unit);
                        break;
                }
                if (mask) {
                        rd->rp = rp;
                        rd++;
                }
        }
}

static u64 rapl_unit_xlate(struct rapl_domain *rd, enum unit_type type,
                        u64 value, int to_raw)
{
        u64 units = 1;
        struct rapl_package *rp = rd->rp;
        u64 scale = 1;

        switch (type) {
        case POWER_UNIT:
                units = rp->power_unit;
                break;
        case ENERGY_UNIT:
                scale = ENERGY_UNIT_SCALE;
                /* per domain unit takes precedence */
                if (rd && rd->domain_energy_unit)
                        units = rd->domain_energy_unit;
                else
                        units = rp->energy_unit;
                break;
        case TIME_UNIT:
                return rapl_defaults->compute_time_window(rp, value, to_raw);
        case ARBITRARY_UNIT:
        default:
                return value;
        };

        if (to_raw)
                return div64_u64(value, units) * scale;

        value *= units;

        return div64_u64(value, scale);
}

/* in the order of enum rapl_primitives */
static struct rapl_primitive_info rpi[] = {
        /* name, mask, shift, msr index, unit divisor */
        PRIMITIVE_INFO_INIT(ENERGY_COUNTER, ENERGY_STATUS_MASK, 0,
                                RAPL_DOMAIN_MSR_STATUS, ENERGY_UNIT, 0),
        PRIMITIVE_INFO_INIT(POWER_LIMIT1, POWER_LIMIT1_MASK, 0,
                                RAPL_DOMAIN_MSR_LIMIT, POWER_UNIT, 0),
        PRIMITIVE_INFO_INIT(POWER_LIMIT2, POWER_LIMIT2_MASK, 32,
                                RAPL_DOMAIN_MSR_LIMIT, POWER_UNIT, 0),
        PRIMITIVE_INFO_INIT(FW_LOCK, POWER_PP_LOCK, 31,
                                RAPL_DOMAIN_MSR_LIMIT, ARBITRARY_UNIT, 0),
        PRIMITIVE_INFO_INIT(PL1_ENABLE, POWER_LIMIT1_ENABLE, 15,
                                RAPL_DOMAIN_MSR_LIMIT, ARBITRARY_UNIT, 0),
        PRIMITIVE_INFO_INIT(PL1_CLAMP, POWER_LIMIT1_CLAMP, 16,
                                RAPL_DOMAIN_MSR_LIMIT, ARBITRARY_UNIT, 0),
        PRIMITIVE_INFO_INIT(PL2_ENABLE, POWER_LIMIT2_ENABLE, 47,
                                RAPL_DOMAIN_MSR_LIMIT, ARBITRARY_UNIT, 0),
        PRIMITIVE_INFO_INIT(PL2_CLAMP, POWER_LIMIT2_CLAMP, 48,
                                RAPL_DOMAIN_MSR_LIMIT, ARBITRARY_UNIT, 0),
        PRIMITIVE_INFO_INIT(TIME_WINDOW1, TIME_WINDOW1_MASK, 17,
                                RAPL_DOMAIN_MSR_LIMIT, TIME_UNIT, 0),
        PRIMITIVE_INFO_INIT(TIME_WINDOW2, TIME_WINDOW2_MASK, 49,
                                RAPL_DOMAIN_MSR_LIMIT, TIME_UNIT, 0),
        PRIMITIVE_INFO_INIT(THERMAL_SPEC_POWER, POWER_INFO_THERMAL_SPEC_MASK,
                                0, RAPL_DOMAIN_MSR_INFO, POWER_UNIT, 0),
        PRIMITIVE_INFO_INIT(MAX_POWER, POWER_INFO_MAX_MASK, 32,
                                RAPL_DOMAIN_MSR_INFO, POWER_UNIT, 0),
        PRIMITIVE_INFO_INIT(MIN_POWER, POWER_INFO_MIN_MASK, 16,
                                RAPL_DOMAIN_MSR_INFO, POWER_UNIT, 0),
        PRIMITIVE_INFO_INIT(MAX_TIME_WINDOW, POWER_INFO_MAX_TIME_WIN_MASK, 48,
                                RAPL_DOMAIN_MSR_INFO, TIME_UNIT, 0),
        PRIMITIVE_INFO_INIT(THROTTLED_TIME, PERF_STATUS_THROTTLE_TIME_MASK, 0,
                                RAPL_DOMAIN_MSR_PERF, TIME_UNIT, 0),
        PRIMITIVE_INFO_INIT(PRIORITY_LEVEL, PP_POLICY_MASK, 0,
                                RAPL_DOMAIN_MSR_POLICY, ARBITRARY_UNIT, 0),
        /* non-hardware */
        PRIMITIVE_INFO_INIT(AVERAGE_POWER, 0, 0, 0, POWER_UNIT,
                                RAPL_PRIMITIVE_DERIVED),
        {NULL, 0, 0, 0},
};

/* Read primitive data based on its related struct rapl_primitive_info.
 * if xlate flag is set, return translated data based on data units, i.e.
 * time, energy, and power.
 * RAPL MSRs are non-architectual and are laid out not consistently across
 * domains. Here we use primitive info to allow writing consolidated access
 * functions.
 * For a given primitive, it is processed by MSR mask and shift. Unit conversion
 * is pre-assigned based on RAPL unit MSRs read at init time.
 * 63-------------------------- 31--------------------------- 0
 * |                           xxxxx (mask)                   |
 * |                                |<- shift ----------------|
 * 63-------------------------- 31--------------------------- 0
 */
static int rapl_read_data_raw(struct rapl_domain *rd,
                        enum rapl_primitives prim,
                        bool xlate, u64 *data)
{
        u64 value, final;
        u32 msr;
        struct rapl_primitive_info *rp = &rpi[prim];
        int cpu;

        if (!rp->name || rp->flag & RAPL_PRIMITIVE_DUMMY)
                return -EINVAL;

        msr = rd->msrs[rp->id];
        if (!msr)
                return -EINVAL;

        cpu = rd->rp->lead_cpu;

        /* special-case package domain, which uses a different bit*/
        if (prim == FW_LOCK && rd->id == RAPL_DOMAIN_PACKAGE) {
                rp->mask = POWER_PACKAGE_LOCK;
                rp->shift = 63;
        }
        /* non-hardware data are collected by the polling thread */
        if (rp->flag & RAPL_PRIMITIVE_DERIVED) {
                *data = rd->rdd.primitives[prim];
                return 0;
        }

        if (rdmsrl_safe_on_cpu(cpu, msr, &value)) {
                pr_debug("failed to read msr 0x%x on cpu %d\n", msr, cpu);
                return -EIO;
        }

        final = value & rp->mask;
        final = final >> rp->shift;
        if (xlate)
                *data = rapl_unit_xlate(rd, rp->unit, final, 0);
        else
                *data = final;

        return 0;
}


static int msrl_update_safe(u32 msr_no, u64 clear_mask, u64 set_mask)
{
        int err;
        u64 val;

        err = rdmsrl_safe(msr_no, &val);
        if (err)
                goto out;

        val &= ~clear_mask;
        val |= set_mask;

        err = wrmsrl_safe(msr_no, val);

out:
        return err;
}

static void msrl_update_func(void *info)
{
        struct msrl_action *ma = info;

        ma->err = msrl_update_safe(ma->msr_no, ma->clear_mask, ma->set_mask);
}

/* Similar use of primitive info in the read counterpart */
static int rapl_write_data_raw(struct rapl_domain *rd,
                        enum rapl_primitives prim,
                        unsigned long long value)
{
        struct rapl_primitive_info *rp = &rpi[prim];
        int cpu;
        u64 bits;
        struct msrl_action ma;
        int ret;

        cpu = rd->rp->lead_cpu;
        bits = rapl_unit_xlate(rd, rp->unit, value, 1);
        bits |= bits << rp->shift;
        memset(&ma, 0, sizeof(ma));

        ma.msr_no = rd->msrs[rp->id];
        ma.clear_mask = rp->mask;
        ma.set_mask = bits;

        ret = smp_call_function_single(cpu, msrl_update_func, &ma, 1);
        if (ret)
                WARN_ON_ONCE(ret);
        else
                ret = ma.err;

        return ret;
}

/*
 * Raw RAPL data stored in MSRs are in certain scales. We need to
 * convert them into standard units based on the units reported in
 * the RAPL unit MSRs. This is specific to CPUs as the method to
 * calculate units differ on different CPUs.
 * We convert the units to below format based on CPUs.
 * i.e.
 * energy unit: picoJoules  : Represented in picoJoules by default
 * power unit : microWatts  : Represented in milliWatts by default
 * time unit  : microseconds: Represented in seconds by default
 */
static int rapl_check_unit_core(struct rapl_package *rp, int cpu)
{
        u64 msr_val;
        u32 value;

        if (rdmsrl_safe_on_cpu(cpu, MSR_RAPL_POWER_UNIT, &msr_val)) {
                pr_err("Failed to read power unit MSR 0x%x on CPU %d, exit.\n",
                        MSR_RAPL_POWER_UNIT, cpu);
                return -ENODEV;
        }

        value = (msr_val & ENERGY_UNIT_MASK) >> ENERGY_UNIT_OFFSET;
        rp->energy_unit = ENERGY_UNIT_SCALE * 1000000 / (1 << value);

        value = (msr_val & POWER_UNIT_MASK) >> POWER_UNIT_OFFSET;
        rp->power_unit = 1000000 / (1 << value);

        value = (msr_val & TIME_UNIT_MASK) >> TIME_UNIT_OFFSET;
        rp->time_unit = 1000000 / (1 << value);

        pr_debug("Core CPU package %d energy=%dpJ, time=%dus, power=%duW\n",
                rp->id, rp->energy_unit, rp->time_unit, rp->power_unit);

        return 0;
}

static int rapl_check_unit_atom(struct rapl_package *rp, int cpu)
{
        u64 msr_val;
        u32 value;

        if (rdmsrl_safe_on_cpu(cpu, MSR_RAPL_POWER_UNIT, &msr_val)) {
                pr_err("Failed to read power unit MSR 0x%x on CPU %d, exit.\n",
                        MSR_RAPL_POWER_UNIT, cpu);
                return -ENODEV;
        }
        value = (msr_val & ENERGY_UNIT_MASK) >> ENERGY_UNIT_OFFSET;
        rp->energy_unit = ENERGY_UNIT_SCALE * 1 << value;

        value = (msr_val & POWER_UNIT_MASK) >> POWER_UNIT_OFFSET;
        rp->power_unit = (1 << value) * 1000;

        value = (msr_val & TIME_UNIT_MASK) >> TIME_UNIT_OFFSET;
        rp->time_unit = 1000000 / (1 << value);

        pr_debug("Atom package %d energy=%dpJ, time=%dus, power=%duW\n",
                rp->id, rp->energy_unit, rp->time_unit, rp->power_unit);

        return 0;
}

static void power_limit_irq_save_cpu(void *info)
{
        u32 l, h = 0;
        struct rapl_package *rp = (struct rapl_package *)info;

        /* save the state of PLN irq mask bit before disabling it */
        rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);
        if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED)) {
                rp->power_limit_irq = l & PACKAGE_THERM_INT_PLN_ENABLE;
                rp->power_limit_irq |= PACKAGE_PLN_INT_SAVED;
        }
        l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
        wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
}


/* REVISIT:
 * When package power limit is set artificially low by RAPL, LVT
 * thermal interrupt for package power limit should be ignored
 * since we are not really exceeding the real limit. The intention
 * is to avoid excessive interrupts while we are trying to save power.
 * A useful feature might be routing the package_power_limit interrupt
 * to userspace via eventfd. once we have a usecase, this is simple
 * to do by adding an atomic notifier.
 */

static void package_power_limit_irq_save(struct rapl_package *rp)
{
        if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
                return;

        smp_call_function_single(rp->lead_cpu, power_limit_irq_save_cpu, rp, 1);
}

static void power_limit_irq_restore_cpu(void *info)
{
        u32 l, h = 0;
        struct rapl_package *rp = (struct rapl_package *)info;

        rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);

        if (rp->power_limit_irq & PACKAGE_THERM_INT_PLN_ENABLE)
                l |= PACKAGE_THERM_INT_PLN_ENABLE;
        else
                l &= ~PACKAGE_THERM_INT_PLN_ENABLE;

        wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
}

/* restore per package power limit interrupt enable state */
static void package_power_limit_irq_restore(struct rapl_package *rp)
{
        if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
                return;

        /* irq enable state not saved, nothing to restore */
        if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED))
                return;

        smp_call_function_single(rp->lead_cpu, power_limit_irq_restore_cpu, rp, 1);
}

static void set_floor_freq_default(struct rapl_domain *rd, bool mode)
{
        int nr_powerlimit = find_nr_power_limit(rd);

        /* always enable clamp such that p-state can go below OS requested
         * range. power capping priority over guranteed frequency.
         */
        rapl_write_data_raw(rd, PL1_CLAMP, mode);

        /* some domains have pl2 */
        if (nr_powerlimit > 1) {
                rapl_write_data_raw(rd, PL2_ENABLE, mode);
                rapl_write_data_raw(rd, PL2_CLAMP, mode);
        }
}

static void set_floor_freq_atom(struct rapl_domain *rd, bool enable)
{
        static u32 power_ctrl_orig_val;
        u32 mdata;

        if (!rapl_defaults->floor_freq_reg_addr) {
                pr_err("Invalid floor frequency config register\n");
                return;
        }

        if (!power_ctrl_orig_val)
                iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_CR_READ,
                              rapl_defaults->floor_freq_reg_addr,
                              &power_ctrl_orig_val);
        mdata = power_ctrl_orig_val;
        if (enable) {
                mdata &= ~(0x7f << 8);
                mdata |= 1 << 8;
        }
        iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_CR_WRITE,
                       rapl_defaults->floor_freq_reg_addr, mdata);
}

static u64 rapl_compute_time_window_core(struct rapl_package *rp, u64 value,
                                        bool to_raw)
{

        u64 f, y; /* fraction and exp. used for time unit */

        /*
         * Special processing based on 2^Y*(1+F/4), refer
         * to Intel Software Developer's manual Vol.3B: CH 14.9.3.
         */
        if (!to_raw) {
                f = (value & 0x60) >> 5;
                y = value & 0x1f;
                value = (1 << y) * (4 + f) * rp->time_unit / 4;
        } else {
                do_div(value, rp->time_unit);
                y = ilog2(value);
                f = div64_u64(4 * (value - (1 << y)), 1 << y);
                value = (y & 0x1f) | ((f & 0x3) << 5);
        }
        return value;
}

static u64 rapl_compute_time_window_atom(struct rapl_package *rp, u64 value,
                                        bool to_raw)
{
        /*
         * Atom time unit encoding is straight forward val * time_unit,
         * where time_unit is default to 1 sec. Never 0.
         */
        if (!to_raw)
                return (value) ? value *= rp->time_unit : rp->time_unit;
        else
                value = div64_u64(value, rp->time_unit);

        return value;
}

static const struct rapl_defaults rapl_defaults_core = {
        .floor_freq_reg_addr = 0,
        .check_unit = rapl_check_unit_core,
        .set_floor_freq = set_floor_freq_default,
        .compute_time_window = rapl_compute_time_window_core,
};

static const struct rapl_defaults rapl_defaults_hsw_server = {
        .check_unit = rapl_check_unit_core,
        .set_floor_freq = set_floor_freq_default,
        .compute_time_window = rapl_compute_time_window_core,
        .dram_domain_energy_unit = 15300,
};

static const struct rapl_defaults rapl_defaults_byt = {
        .floor_freq_reg_addr = IOSF_CPU_POWER_BUDGET_CTL_BYT,
        .check_unit = rapl_check_unit_atom,
        .set_floor_freq = set_floor_freq_atom,
        .compute_time_window = rapl_compute_time_window_atom,
};

static const struct rapl_defaults rapl_defaults_tng = {
        .floor_freq_reg_addr = IOSF_CPU_POWER_BUDGET_CTL_TNG,
        .check_unit = rapl_check_unit_atom,
        .set_floor_freq = set_floor_freq_atom,
        .compute_time_window = rapl_compute_time_window_atom,
};

static const struct rapl_defaults rapl_defaults_ann = {
        .floor_freq_reg_addr = 0,
        .check_unit = rapl_check_unit_atom,
        .set_floor_freq = NULL,
        .compute_time_window = rapl_compute_time_window_atom,
};

static const struct rapl_defaults rapl_defaults_cht = {
        .floor_freq_reg_addr = 0,
        .check_unit = rapl_check_unit_atom,
        .set_floor_freq = NULL,
        .compute_time_window = rapl_compute_time_window_atom,
};

#define RAPL_CPU(_model, _ops) {                        \
                .vendor = X86_VENDOR_INTEL,             \
                .family = 6,                            \
                .model = _model,                        \
                .driver_data = (kernel_ulong_t)&_ops,   \
                }

static const struct x86_cpu_id rapl_ids[] __initconst = {
        RAPL_CPU(0x2a, rapl_defaults_core),/* Sandy Bridge */
        RAPL_CPU(0x2d, rapl_defaults_core),/* Sandy Bridge EP */
        RAPL_CPU(0x37, rapl_defaults_byt),/* Valleyview */
        RAPL_CPU(0x3a, rapl_defaults_core),/* Ivy Bridge */
        RAPL_CPU(0x3c, rapl_defaults_core),/* Haswell */
        RAPL_CPU(0x3d, rapl_defaults_core),/* Broadwell */
        RAPL_CPU(0x3f, rapl_defaults_hsw_server),/* Haswell servers */
        RAPL_CPU(0x4f, rapl_defaults_hsw_server),/* Broadwell servers */
        RAPL_CPU(0x45, rapl_defaults_core),/* Haswell ULT */
        RAPL_CPU(0x46, rapl_defaults_core),/* Haswell */
        RAPL_CPU(0x47, rapl_defaults_core),/* Broadwell-H */
        RAPL_CPU(0x4E, rapl_defaults_core),/* Skylake */
        RAPL_CPU(0x4C, rapl_defaults_cht),/* Braswell/Cherryview */
        RAPL_CPU(0x4A, rapl_defaults_tng),/* Tangier */
        RAPL_CPU(0x56, rapl_defaults_core),/* Future Xeon */
        RAPL_CPU(0x5A, rapl_defaults_ann),/* Annidale */
        RAPL_CPU(0X5C, rapl_defaults_core),/* Broxton */
        RAPL_CPU(0x5E, rapl_defaults_core),/* Skylake-H/S */
        RAPL_CPU(0x57, rapl_defaults_hsw_server),/* Knights Landing */
        {}
};
MODULE_DEVICE_TABLE(x86cpu, rapl_ids);

/* read once for all raw primitive data for all packages, domains */
static void rapl_update_domain_data(void)
{
        int dmn, prim;
        u64 val;
        struct rapl_package *rp;

        list_for_each_entry(rp, &rapl_packages, plist) {
                for (dmn = 0; dmn < rp->nr_domains; dmn++) {
                        pr_debug("update package %d domain %s data\n", rp->id,
                                rp->domains[dmn].name);
                        /* exclude non-raw primitives */
                        for (prim = 0; prim < NR_RAW_PRIMITIVES; prim++)
                                if (!rapl_read_data_raw(&rp->domains[dmn], prim,
                                                                rpi[prim].unit,
                                                                &val))
                                        rp->domains[dmn].rdd.primitives[prim] =
                                                                        val;
                }
        }

}

static int rapl_unregister_powercap(void)
{
        struct rapl_package *rp;
        struct rapl_domain *rd, *rd_package = NULL;

        /* unregister all active rapl packages from the powercap layer,
         * hotplug lock held
         */
        list_for_each_entry(rp, &rapl_packages, plist) {
                package_power_limit_irq_restore(rp);

                for (rd = rp->domains; rd < rp->domains + rp->nr_domains;
                     rd++) {
                        pr_debug("remove package, undo power limit on %d: %s\n",
                                rp->id, rd->name);
                        rapl_write_data_raw(rd, PL1_ENABLE, 0);
                        rapl_write_data_raw(rd, PL1_CLAMP, 0);
                        if (find_nr_power_limit(rd) > 1) {
                                rapl_write_data_raw(rd, PL2_ENABLE, 0);
                                rapl_write_data_raw(rd, PL2_CLAMP, 0);
                        }
                        if (rd->id == RAPL_DOMAIN_PACKAGE) {
                                rd_package = rd;
                                continue;
                        }
                        powercap_unregister_zone(control_type, &rd->power_zone);
                }
                /* do the package zone last */
                if (rd_package)
                        powercap_unregister_zone(control_type,
                                                &rd_package->power_zone);
        }
        powercap_unregister_control_type(control_type);

        return 0;
}

static int rapl_package_register_powercap(struct rapl_package *rp)
{
        struct rapl_domain *rd;
        int ret = 0;
        char dev_name[17]; /* max domain name = 7 + 1 + 8 for int + 1 for null*/
        struct powercap_zone *power_zone = NULL;
        int nr_pl;

        /* first we register package domain as the parent zone*/
        for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
                if (rd->id == RAPL_DOMAIN_PACKAGE) {
                        nr_pl = find_nr_power_limit(rd);
                        pr_debug("register socket %d package domain %s\n",
                                rp->id, rd->name);
                        memset(dev_name, 0, sizeof(dev_name));
                        snprintf(dev_name, sizeof(dev_name), "%s-%d",
                                rd->name, rp->id);
                        power_zone = powercap_register_zone(&rd->power_zone,
                                                        control_type,
                                                        dev_name, NULL,
                                                        &zone_ops[rd->id],
                                                        nr_pl,
                                                        &constraint_ops);
                        if (IS_ERR(power_zone)) {
                                pr_debug("failed to register package, %d\n",
                                        rp->id);
                                ret = PTR_ERR(power_zone);
                                goto exit_package;
                        }
                        /* track parent zone in per package/socket data */
                        rp->power_zone = power_zone;
                        /* done, only one package domain per socket */
                        break;
                }
        }
        if (!power_zone) {
                pr_err("no package domain found, unknown topology!\n");
                ret = -ENODEV;
                goto exit_package;
        }
        /* now register domains as children of the socket/package*/
        for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
                if (rd->id == RAPL_DOMAIN_PACKAGE)
                        continue;
                /* number of power limits per domain varies */
                nr_pl = find_nr_power_limit(rd);
                power_zone = powercap_register_zone(&rd->power_zone,
                                                control_type, rd->name,
                                                rp->power_zone,
                                                &zone_ops[rd->id], nr_pl,
                                                &constraint_ops);

                if (IS_ERR(power_zone)) {
                        pr_debug("failed to register power_zone, %d:%s:%s\n",
                                rp->id, rd->name, dev_name);
                        ret = PTR_ERR(power_zone);
                        goto err_cleanup;
                }
        }

exit_package:
        return ret;
err_cleanup:
        /* clean up previously initialized domains within the package if we
         * failed after the first domain setup.
         */
        while (--rd >= rp->domains) {
                pr_debug("unregister package %d domain %s\n", rp->id, rd->name);
                powercap_unregister_zone(control_type, &rd->power_zone);
        }

        return ret;
}

static int rapl_register_powercap(void)
{
        struct rapl_domain *rd;
        struct rapl_package *rp;
        int ret = 0;

        control_type = powercap_register_control_type(NULL, "intel-rapl", NULL);
        if (IS_ERR(control_type)) {
                pr_debug("failed to register powercap control_type.\n");
                return PTR_ERR(control_type);
        }
        /* read the initial data */
        rapl_update_domain_data();
        list_for_each_entry(rp, &rapl_packages, plist)
                if (rapl_package_register_powercap(rp))
                        goto err_cleanup_package;
        return ret;

err_cleanup_package:
        /* clean up previously initialized packages */
        list_for_each_entry_continue_reverse(rp, &rapl_packages, plist) {
                for (rd = rp->domains; rd < rp->domains + rp->nr_domains;
                     rd++) {
                        pr_debug("unregister zone/package %d, %s domain\n",
                                rp->id, rd->name);
                        powercap_unregister_zone(control_type, &rd->power_zone);
                }
        }

        return ret;
}

static int rapl_check_domain(int cpu, int domain)
{
        unsigned msr;
        u64 val = 0;

        switch (domain) {
        case RAPL_DOMAIN_PACKAGE:
                msr = MSR_PKG_ENERGY_STATUS;
                break;
        case RAPL_DOMAIN_PP0:
                msr = MSR_PP0_ENERGY_STATUS;
                break;
        case RAPL_DOMAIN_PP1:
                msr = MSR_PP1_ENERGY_STATUS;
                break;
        case RAPL_DOMAIN_DRAM:
                msr = MSR_DRAM_ENERGY_STATUS;
                break;
        default:
                pr_err("invalid domain id %d\n", domain);
                return -EINVAL;
        }
        /* make sure domain counters are available and contains non-zero
         * values, otherwise skip it.
         */
        if (rdmsrl_safe_on_cpu(cpu, msr, &val) || !val)
                return -ENODEV;

        return 0;
}

/* Detect active and valid domains for the given CPU, caller must
 * ensure the CPU belongs to the targeted package and CPU hotlug is disabled.
 */
static int rapl_detect_domains(struct rapl_package *rp, int cpu)
{
        int i;
        int ret = 0;
        struct rapl_domain *rd;
        u64 locked;

        for (i = 0; i < RAPL_DOMAIN_MAX; i++) {
                /* use physical package id to read counters */
                if (!rapl_check_domain(cpu, i)) {
                        rp->domain_map |= 1 << i;
                        pr_info("Found RAPL domain %s\n", rapl_domain_names[i]);
                }
        }
        rp->nr_domains = bitmap_weight(&rp->domain_map, RAPL_DOMAIN_MAX);
        if (!rp->nr_domains) {
                pr_err("no valid rapl domains found in package %d\n", rp->id);
                ret = -ENODEV;
                goto done;
        }
        pr_debug("found %d domains on package %d\n", rp->nr_domains, rp->id);

        rp->domains = kcalloc(rp->nr_domains + 1, sizeof(struct rapl_domain),
                        GFP_KERNEL);
        if (!rp->domains) {
                ret = -ENOMEM;
                goto done;
        }
        rapl_init_domains(rp);

        for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
                /* check if the domain is locked by BIOS */
                ret = rapl_read_data_raw(rd, FW_LOCK, false, &locked);
                if (ret)
                        return ret;
                if (locked) {
                        pr_info("RAPL package %d domain %s locked by BIOS\n",
                                rp->id, rd->name);
                        rd->state |= DOMAIN_STATE_BIOS_LOCKED;
                }
        }


done:
        return ret;
}

static bool is_package_new(int package)
{
        struct rapl_package *rp;

        /* caller prevents cpu hotplug, there will be no new packages added
         * or deleted while traversing the package list, no need for locking.
         */
        list_for_each_entry(rp, &rapl_packages, plist)
                if (package == rp->id)
                        return false;

        return true;
}

/* RAPL interface can be made of a two-level hierarchy: package level and domain
 * level. We first detect the number of packages then domains of each package.
 * We have to consider the possiblity of CPU online/offline due to hotplug and
 * other scenarios.
 */
static int rapl_detect_topology(void)
{
        int i;
        int phy_package_id;
        struct rapl_package *new_package, *rp;

        for_each_online_cpu(i) {
                phy_package_id = topology_physical_package_id(i);
                if (is_package_new(phy_package_id)) {
                        new_package = kzalloc(sizeof(*rp), GFP_KERNEL);
                        if (!new_package) {
                                rapl_cleanup_data();
                                return -ENOMEM;
                        }
                        /* add the new package to the list */
                        new_package->id = phy_package_id;
                        new_package->nr_cpus = 1;
                        /* use the first active cpu of the package to access */
                        new_package->lead_cpu = i;
                        /* check if the package contains valid domains */
                        if (rapl_detect_domains(new_package, i) ||
                                rapl_defaults->check_unit(new_package, i)) {
                                kfree(new_package->domains);
                                kfree(new_package);
                                /* free up the packages already initialized */
                                rapl_cleanup_data();
                                return -ENODEV;
                        }
                        INIT_LIST_HEAD(&new_package->plist);
                        list_add(&new_package->plist, &rapl_packages);
                } else {
                        rp = find_package_by_id(phy_package_id);
                        if (rp)
                                ++rp->nr_cpus;
                }
        }

        return 0;
}

/* called from CPU hotplug notifier, hotplug lock held */
static void rapl_remove_package(struct rapl_package *rp)
{
        struct rapl_domain *rd, *rd_package = NULL;

        for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
                if (rd->id == RAPL_DOMAIN_PACKAGE) {
                        rd_package = rd;
                        continue;
                }
                pr_debug("remove package %d, %s domain\n", rp->id, rd->name);
                powercap_unregister_zone(control_type, &rd->power_zone);
        }
        /* do parent zone last */
        powercap_unregister_zone(control_type, &rd_package->power_zone);
        list_del(&rp->plist);
        kfree(rp);
}

/* called from CPU hotplug notifier, hotplug lock held */
static int rapl_add_package(int cpu)
{
        int ret = 0;
        int phy_package_id;
        struct rapl_package *rp;

        phy_package_id = topology_physical_package_id(cpu);
        rp = kzalloc(sizeof(struct rapl_package), GFP_KERNEL);
        if (!rp)
                return -ENOMEM;

        /* add the new package to the list */
        rp->id = phy_package_id;
        rp->nr_cpus = 1;
        rp->lead_cpu = cpu;

        /* check if the package contains valid domains */
        if (rapl_detect_domains(rp, cpu) ||
                rapl_defaults->check_unit(rp, cpu)) {
                ret = -ENODEV;
                goto err_free_package;
        }
        if (!rapl_package_register_powercap(rp)) {
                INIT_LIST_HEAD(&rp->plist);
                list_add(&rp->plist, &rapl_packages);
                return ret;
        }

err_free_package:
        kfree(rp->domains);
        kfree(rp);

        return ret;
}

/* Handles CPU hotplug on multi-socket systems.
 * If a CPU goes online as the first CPU of the physical package
 * we add the RAPL package to the system. Similarly, when the last
 * CPU of the package is removed, we remove the RAPL package and its
 * associated domains. Cooling devices are handled accordingly at
 * per-domain level.
 */
static int rapl_cpu_callback(struct notifier_block *nfb,
                                unsigned long action, void *hcpu)
{
        unsigned long cpu = (unsigned long)hcpu;
        int phy_package_id;
        struct rapl_package *rp;
        int lead_cpu;

        phy_package_id = topology_physical_package_id(cpu);
        switch (action) {
        case CPU_ONLINE:
        case CPU_ONLINE_FROZEN:
        case CPU_DOWN_FAILED:
        case CPU_DOWN_FAILED_FROZEN:
                rp = find_package_by_id(phy_package_id);
                if (rp)
                        ++rp->nr_cpus;
                else
                        rapl_add_package(cpu);
                break;
        case CPU_DOWN_PREPARE:
        case CPU_DOWN_PREPARE_FROZEN:
                rp = find_package_by_id(phy_package_id);
                if (!rp)
                        break;
                if (--rp->nr_cpus == 0)
                        rapl_remove_package(rp);
                else if (cpu == rp->lead_cpu) {
                        /* choose another active cpu in the package */
                        lead_cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);
                        if (lead_cpu < nr_cpu_ids)
                                rp->lead_cpu = lead_cpu;
                        else /* should never go here */
                                pr_err("no active cpu available for package %d\n",
                                        phy_package_id);
                }
        }

        return NOTIFY_OK;
}

static struct notifier_block rapl_cpu_notifier = {
        .notifier_call = rapl_cpu_callback,
};

static int __init rapl_init(void)
{
        int ret = 0;
        const struct x86_cpu_id *id;

        id = x86_match_cpu(rapl_ids);
        if (!id) {
                pr_err("driver does not support CPU family %d model %d\n",
                        boot_cpu_data.x86, boot_cpu_data.x86_model);

                return -ENODEV;
        }

        rapl_defaults = (struct rapl_defaults *)id->driver_data;

        cpu_notifier_register_begin();

        /* prevent CPU hotplug during detection */
        get_online_cpus();
        ret = rapl_detect_topology();
        if (ret)
                goto done;

        if (rapl_register_powercap()) {
                rapl_cleanup_data();
                ret = -ENODEV;
                goto done;
        }
        __register_hotcpu_notifier(&rapl_cpu_notifier);
done:
        put_online_cpus();
        cpu_notifier_register_done();

        return ret;
}

static void __exit rapl_exit(void)
{
        cpu_notifier_register_begin();
        get_online_cpus();
        __unregister_hotcpu_notifier(&rapl_cpu_notifier);
        rapl_unregister_powercap();
        rapl_cleanup_data();
        put_online_cpus();
        cpu_notifier_register_done();
}

module_init(rapl_init);
module_exit(rapl_exit);

MODULE_DESCRIPTION("Driver for Intel RAPL (Running Average Power Limit)");
MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>");
MODULE_LICENSE("GPL v2");