Initial import

4 files changed, 2247 insertions, 0 deletions

diff --git a/drivers/powercap/Kconfig b/drivers/powercap/Kconfig
new file mode 100644
index 000000000..85727ef6c
--- /dev/null
+++ b/drivers/powercap/Kconfig
@@ -0,0 +1,32 @@
+#
+# Generic power capping sysfs interface configuration
+#
+
+menuconfig POWERCAP
+	bool "Generic powercap sysfs driver"
+	help
+	  The power capping sysfs interface allows kernel subsystems to expose power
+	  capping settings to user space in a consistent way.  Usually, it consists
+	  of multiple control types that determine which settings may be exposed and
+	  power zones representing parts of the system that can be subject to power
+	  capping.
+
+	  If you want this code to be compiled in, say Y here.
+
+if POWERCAP
+# Client driver configurations go here.
+config INTEL_RAPL
+	tristate "Intel RAPL Support"
+	depends on X86 && IOSF_MBI
+	default n
+	---help---
+	  This enables support for the Intel Running Average Power Limit (RAPL)
+	  technology which allows power limits to be enforced and monitored on
+	  modern Intel processors (Sandy Bridge and later).
+
+	  In RAPL, the platform level settings are divided into domains for
+	  fine grained control. These domains include processor package, DRAM
+	  controller, CPU core (Power Plance 0), graphics uncore (Power Plane
+	  1), etc.
+
+endif
diff --git a/drivers/powercap/Makefile b/drivers/powercap/Makefile
new file mode 100644
index 000000000..0a21ef313
--- /dev/null
+++ b/drivers/powercap/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_POWERCAP)	+= powercap_sys.o
+obj-$(CONFIG_INTEL_RAPL) += intel_rapl.o
diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
new file mode 100644
index 000000000..fd2432316
--- /dev/null
+++ b/drivers/powercap/intel_rapl.c
@@ -0,0 +1,1523 @@
+/*
+ * 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;
+};
+
+
+#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_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;
+	int package_id;
+};
+#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;
+};
+
+struct rapl_defaults {
+	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 (0x2)
+
+#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, int package,
+			enum unit_type type, u64 value,
+			int to_raw);
+static void package_power_limit_irq_save(int package_id);
+
+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 to ensure CPU hotplug lock is held */
+static int find_active_cpu_on_package(int package_id)
+{
+	int i;
+
+	for_each_online_cpu(i) {
+		if (topology_physical_package_id(i) == package_id)
+			return i;
+	}
+	/* all CPUs on this package are offline */
+
+	return -ENODEV;
+}
+
+/* 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, 0, 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;
+
+	/* 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) {
+		rp = find_package_by_id(rd->package_id);
+		if (!rp) {
+			dev_warn(&power_zone->dev, "no package id %s\n",
+				rd->name);
+			return -ENODEV;
+		}
+		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);
+	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 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 = find_package_by_id(rd->package_id);
+	if (!rp) {
+		ret = -ENODEV;
+		goto set_exit;
+	}
+
+	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(rd->package_id);
+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 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->package_id = rp->id;
+			rd++;
+		}
+	}
+}
+
+static u64 rapl_unit_xlate(struct rapl_domain *rd, int package,
+			enum unit_type type, u64 value,
+			int to_raw)
+{
+	u64 units = 1;
+	struct rapl_package *rp;
+	u64 scale = 1;
+
+	rp = find_package_by_id(package);
+	if (!rp)
+		return value;
+
+	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;
+	/* use physical package id to look up active cpus */
+	cpu = find_active_cpu_on_package(rd->package_id);
+	if (cpu < 0)
+		return 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, rd->package_id, rp->unit, final, 0);
+	else
+		*data = final;
+
+	return 0;
+}
+
+/* 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)
+{
+	u64 msr_val;
+	u32 msr;
+	struct rapl_primitive_info *rp = &rpi[prim];
+	int cpu;
+
+	cpu = find_active_cpu_on_package(rd->package_id);
+	if (cpu < 0)
+		return cpu;
+	msr = rd->msrs[rp->id];
+	if (rdmsrl_safe_on_cpu(cpu, msr, &msr_val)) {
+		dev_dbg(&rd->power_zone.dev,
+			"failed to read msr 0x%x on cpu %d\n", msr, cpu);
+		return -EIO;
+	}
+	value = rapl_unit_xlate(rd, rd->package_id, rp->unit, value, 1);
+	msr_val &= ~rp->mask;
+	msr_val |= value << rp->shift;
+	if (wrmsrl_safe_on_cpu(cpu, msr, msr_val)) {
+		dev_dbg(&rd->power_zone.dev,
+			"failed to write msr 0x%x on cpu %d\n", msr, cpu);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * 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;
+}
+
+
+/* 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(int package_id)
+{
+	u32 l, h = 0;
+	int cpu;
+	struct rapl_package *rp;
+
+	rp = find_package_by_id(package_id);
+	if (!rp)
+		return;
+
+	if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
+		return;
+
+	cpu = find_active_cpu_on_package(package_id);
+	if (cpu < 0)
+		return;
+	/* save the state of PLN irq mask bit before disabling it */
+	rdmsr_safe_on_cpu(cpu, 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_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+}
+
+/* restore per package power limit interrupt enable state */
+static void package_power_limit_irq_restore(int package_id)
+{
+	u32 l, h;
+	int cpu;
+	struct rapl_package *rp;
+
+	rp = find_package_by_id(package_id);
+	if (!rp)
+		return;
+
+	if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
+		return;
+
+	cpu = find_active_cpu_on_package(package_id);
+	if (cpu < 0)
+		return;
+
+	/* irq enable state not saved, nothing to restore */
+	if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED))
+		return;
+	rdmsr_safe_on_cpu(cpu, 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_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+}
+
+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 (!power_ctrl_orig_val)
+		iosf_mbi_read(BT_MBI_UNIT_PMC, BT_MBI_PMC_READ,
+			IOSF_CPU_POWER_BUDGET_CTL, &power_ctrl_orig_val);
+	mdata = power_ctrl_orig_val;
+	if (enable) {
+		mdata &= ~(0x7f << 8);
+		mdata |= 1 << 8;
+	}
+	iosf_mbi_write(BT_MBI_UNIT_PMC, BT_MBI_PMC_WRITE,
+		IOSF_CPU_POWER_BUDGET_CTL, 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 = {
+	.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_atom = {
+	.check_unit = rapl_check_unit_atom,
+	.set_floor_freq = set_floor_freq_atom,
+	.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_atom),/* 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(0x4E, rapl_defaults_core),/* Skylake */
+	RAPL_CPU(0x4C, rapl_defaults_atom),/* Braswell */
+	RAPL_CPU(0x4A, rapl_defaults_atom),/* Tangier */
+	RAPL_CPU(0x56, rapl_defaults_core),/* Future Xeon */
+	RAPL_CPU(0x5A, rapl_defaults_atom),/* Annidale */
+	{}
+};
+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->id);
+
+		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, PL2_ENABLE, 0);
+			rapl_write_data_raw(rd, PL1_CLAMP, 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 */
+		if (rapl_read_data_raw(rd, FW_LOCK, false, &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;
+
+			/* 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;
+	/* 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;
+
+	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);
+	}
+
+	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");
diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c
new file mode 100644
index 000000000..84419af16
--- /dev/null
+++ b/drivers/powercap/powercap_sys.c
@@ -0,0 +1,690 @@
+/*
+ * Power capping class
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/powercap.h>
+
+#define to_powercap_zone(n) container_of(n, struct powercap_zone, dev)
+#define to_powercap_control_type(n) \
+			container_of(n, struct powercap_control_type, dev)
+
+/* Power zone show function */
+#define define_power_zone_show(_attr)		\
+static ssize_t _attr##_show(struct device *dev, \
+					struct device_attribute *dev_attr,\
+					char *buf) \
+{ \
+	u64 value; \
+	ssize_t len = -EINVAL; \
+	struct powercap_zone *power_zone = to_powercap_zone(dev); \
+	\
+	if (power_zone->ops->get_##_attr) { \
+		if (!power_zone->ops->get_##_attr(power_zone, &value)) \
+			len = sprintf(buf, "%lld\n", value); \
+	} \
+	\
+	return len; \
+}
+
+/* The only meaningful input is 0 (reset), others are silently ignored */
+#define define_power_zone_store(_attr)		\
+static ssize_t _attr##_store(struct device *dev,\
+				struct device_attribute *dev_attr, \
+				const char *buf, size_t count) \
+{ \
+	int err; \
+	struct powercap_zone *power_zone = to_powercap_zone(dev); \
+	u64 value; \
+	\
+	err = kstrtoull(buf, 10, &value); \
+	if (err) \
+		return -EINVAL; \
+	if (value) \
+		return count; \
+	if (power_zone->ops->reset_##_attr) { \
+		if (!power_zone->ops->reset_##_attr(power_zone)) \
+			return count; \
+	} \
+	\
+	return -EINVAL; \
+}
+
+/* Power zone constraint show function */
+#define define_power_zone_constraint_show(_attr) \
+static ssize_t show_constraint_##_attr(struct device *dev, \
+				struct device_attribute *dev_attr,\
+				char *buf) \
+{ \
+	u64 value; \
+	ssize_t len = -ENODATA; \
+	struct powercap_zone *power_zone = to_powercap_zone(dev); \
+	int id; \
+	struct powercap_zone_constraint *pconst;\
+	\
+	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
+		return -EINVAL; \
+	if (id >= power_zone->const_id_cnt)	\
+		return -EINVAL; \
+	pconst = &power_zone->constraints[id]; \
+	if (pconst && pconst->ops && pconst->ops->get_##_attr) { \
+		if (!pconst->ops->get_##_attr(power_zone, id, &value)) \
+			len = sprintf(buf, "%lld\n", value); \
+	} \
+	\
+	return len; \
+}
+
+/* Power zone constraint store function */
+#define define_power_zone_constraint_store(_attr) \
+static ssize_t store_constraint_##_attr(struct device *dev,\
+				struct device_attribute *dev_attr, \
+				const char *buf, size_t count) \
+{ \
+	int err; \
+	u64 value; \
+	struct powercap_zone *power_zone = to_powercap_zone(dev); \
+	int id; \
+	struct powercap_zone_constraint *pconst;\
+	\
+	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
+		return -EINVAL; \
+	if (id >= power_zone->const_id_cnt)	\
+		return -EINVAL; \
+	pconst = &power_zone->constraints[id]; \
+	err = kstrtoull(buf, 10, &value); \
+	if (err) \
+		return -EINVAL; \
+	if (pconst && pconst->ops && pconst->ops->set_##_attr) { \
+		if (!pconst->ops->set_##_attr(power_zone, id, value)) \
+			return count; \
+	} \
+	\
+	return -ENODATA; \
+}
+
+/* Power zone information callbacks */
+define_power_zone_show(power_uw);
+define_power_zone_show(max_power_range_uw);
+define_power_zone_show(energy_uj);
+define_power_zone_store(energy_uj);
+define_power_zone_show(max_energy_range_uj);
+
+/* Power zone attributes */
+static DEVICE_ATTR_RO(max_power_range_uw);
+static DEVICE_ATTR_RO(power_uw);
+static DEVICE_ATTR_RO(max_energy_range_uj);
+static DEVICE_ATTR_RW(energy_uj);
+
+/* Power zone constraint attributes callbacks */
+define_power_zone_constraint_show(power_limit_uw);
+define_power_zone_constraint_store(power_limit_uw);
+define_power_zone_constraint_show(time_window_us);
+define_power_zone_constraint_store(time_window_us);
+define_power_zone_constraint_show(max_power_uw);
+define_power_zone_constraint_show(min_power_uw);
+define_power_zone_constraint_show(max_time_window_us);
+define_power_zone_constraint_show(min_time_window_us);
+
+/* For one time seeding of constraint device attributes */
+struct powercap_constraint_attr {
+	struct device_attribute power_limit_attr;
+	struct device_attribute time_window_attr;
+	struct device_attribute max_power_attr;
+	struct device_attribute min_power_attr;
+	struct device_attribute max_time_window_attr;
+	struct device_attribute min_time_window_attr;
+	struct device_attribute name_attr;
+};
+
+static struct powercap_constraint_attr
+				constraint_attrs[MAX_CONSTRAINTS_PER_ZONE];
+
+/* A list of powercap control_types */
+static LIST_HEAD(powercap_cntrl_list);
+/* Mutex to protect list of powercap control_types */
+static DEFINE_MUTEX(powercap_cntrl_list_lock);
+
+#define POWERCAP_CONSTRAINT_NAME_LEN	30 /* Some limit to avoid overflow */
+static ssize_t show_constraint_name(struct device *dev,
+				struct device_attribute *dev_attr,
+				char *buf)
+{
+	const char *name;
+	struct powercap_zone *power_zone = to_powercap_zone(dev);
+	int id;
+	ssize_t len = -ENODATA;
+	struct powercap_zone_constraint *pconst;
+
+	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id))
+		return -EINVAL;
+	if (id >= power_zone->const_id_cnt)
+		return -EINVAL;
+	pconst = &power_zone->constraints[id];
+
+	if (pconst && pconst->ops && pconst->ops->get_name) {
+		name = pconst->ops->get_name(power_zone, id);
+		if (name) {
+			snprintf(buf, POWERCAP_CONSTRAINT_NAME_LEN,
+								"%s\n", name);
+			buf[POWERCAP_CONSTRAINT_NAME_LEN] = '\0';
+			len = strlen(buf);
+		}
+	}
+
+	return len;
+}
+
+static int create_constraint_attribute(int id, const char *name,
+				int mode,
+				struct device_attribute *dev_attr,
+				ssize_t (*show)(struct device *,
+					struct device_attribute *, char *),
+				ssize_t (*store)(struct device *,
+					struct device_attribute *,
+				const char *, size_t)
+				)
+{
+
+	dev_attr->attr.name = kasprintf(GFP_KERNEL, "constraint_%d_%s",
+								id, name);
+	if (!dev_attr->attr.name)
+		return -ENOMEM;
+	dev_attr->attr.mode = mode;
+	dev_attr->show = show;
+	dev_attr->store = store;
+
+	return 0;
+}
+
+static void free_constraint_attributes(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {
+		kfree(constraint_attrs[i].power_limit_attr.attr.name);
+		kfree(constraint_attrs[i].time_window_attr.attr.name);
+		kfree(constraint_attrs[i].name_attr.attr.name);
+		kfree(constraint_attrs[i].max_power_attr.attr.name);
+		kfree(constraint_attrs[i].min_power_attr.attr.name);
+		kfree(constraint_attrs[i].max_time_window_attr.attr.name);
+		kfree(constraint_attrs[i].min_time_window_attr.attr.name);
+	}
+}
+
+static int seed_constraint_attributes(void)
+{
+	int i;
+	int ret;
+
+	for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {
+		ret = create_constraint_attribute(i, "power_limit_uw",
+					S_IWUSR | S_IRUGO,
+					&constraint_attrs[i].power_limit_attr,
+					show_constraint_power_limit_uw,
+					store_constraint_power_limit_uw);
+		if (ret)
+			goto err_alloc;
+		ret = create_constraint_attribute(i, "time_window_us",
+					S_IWUSR | S_IRUGO,
+					&constraint_attrs[i].time_window_attr,
+					show_constraint_time_window_us,
+					store_constraint_time_window_us);
+		if (ret)
+			goto err_alloc;
+		ret = create_constraint_attribute(i, "name", S_IRUGO,
+				&constraint_attrs[i].name_attr,
+				show_constraint_name,
+				NULL);
+		if (ret)
+			goto err_alloc;
+		ret = create_constraint_attribute(i, "max_power_uw", S_IRUGO,
+				&constraint_attrs[i].max_power_attr,
+				show_constraint_max_power_uw,
+				NULL);
+		if (ret)
+			goto err_alloc;
+		ret = create_constraint_attribute(i, "min_power_uw", S_IRUGO,
+				&constraint_attrs[i].min_power_attr,
+				show_constraint_min_power_uw,
+				NULL);
+		if (ret)
+			goto err_alloc;
+		ret = create_constraint_attribute(i, "max_time_window_us",
+				S_IRUGO,
+				&constraint_attrs[i].max_time_window_attr,
+				show_constraint_max_time_window_us,
+				NULL);
+		if (ret)
+			goto err_alloc;
+		ret = create_constraint_attribute(i, "min_time_window_us",
+				S_IRUGO,
+				&constraint_attrs[i].min_time_window_attr,
+				show_constraint_min_time_window_us,
+				NULL);
+		if (ret)
+			goto err_alloc;
+
+	}
+
+	return 0;
+
+err_alloc:
+	free_constraint_attributes();
+
+	return ret;
+}
+
+static int create_constraints(struct powercap_zone *power_zone,
+				int nr_constraints,
+				struct powercap_zone_constraint_ops *const_ops)
+{
+	int i;
+	int ret = 0;
+	int count;
+	struct powercap_zone_constraint *pconst;
+
+	if (!power_zone || !const_ops || !const_ops->get_power_limit_uw ||
+					!const_ops->set_power_limit_uw ||
+					!const_ops->get_time_window_us ||
+					!const_ops->set_time_window_us)
+		return -EINVAL;
+
+	count = power_zone->zone_attr_count;
+	for (i = 0; i < nr_constraints; ++i) {
+		pconst = &power_zone->constraints[i];
+		pconst->ops = const_ops;
+		pconst->id = power_zone->const_id_cnt;
+		power_zone->const_id_cnt++;
+		power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].power_limit_attr.attr;
+		power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].time_window_attr.attr;
+		if (pconst->ops->get_name)
+			power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].name_attr.attr;
+		if (pconst->ops->get_max_power_uw)
+			power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].max_power_attr.attr;
+		if (pconst->ops->get_min_power_uw)
+			power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].min_power_attr.attr;
+		if (pconst->ops->get_max_time_window_us)
+			power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].max_time_window_attr.attr;
+		if (pconst->ops->get_min_time_window_us)
+			power_zone->zone_dev_attrs[count++] =
+				&constraint_attrs[i].min_time_window_attr.attr;
+	}
+	power_zone->zone_attr_count = count;
+
+	return ret;
+}
+
+static bool control_type_valid(void *control_type)
+{
+	struct powercap_control_type *pos = NULL;
+	bool found = false;
+
+	mutex_lock(&powercap_cntrl_list_lock);
+
+	list_for_each_entry(pos, &powercap_cntrl_list, node) {
+		if (pos == control_type) {
+			found = true;
+			break;
+		}
+	}
+	mutex_unlock(&powercap_cntrl_list_lock);
+
+	return found;
+}
+
+static ssize_t name_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct powercap_zone *power_zone = to_powercap_zone(dev);
+
+	return sprintf(buf, "%s\n", power_zone->name);
+}
+
+static DEVICE_ATTR_RO(name);
+
+/* Create zone and attributes in sysfs */
+static void create_power_zone_common_attributes(
+					struct powercap_zone *power_zone)
+{
+	int count = 0;
+
+	power_zone->zone_dev_attrs[count++] = &dev_attr_name.attr;
+	if (power_zone->ops->get_max_energy_range_uj)
+		power_zone->zone_dev_attrs[count++] =
+					&dev_attr_max_energy_range_uj.attr;
+	if (power_zone->ops->get_energy_uj) {
+		if (power_zone->ops->reset_energy_uj)
+			dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUGO;
+		else
+			dev_attr_energy_uj.attr.mode = S_IRUGO;
+		power_zone->zone_dev_attrs[count++] =
+					&dev_attr_energy_uj.attr;
+	}
+	if (power_zone->ops->get_power_uw)
+		power_zone->zone_dev_attrs[count++] =
+					&dev_attr_power_uw.attr;
+	if (power_zone->ops->get_max_power_range_uw)
+		power_zone->zone_dev_attrs[count++] =
+					&dev_attr_max_power_range_uw.attr;
+	power_zone->zone_dev_attrs[count] = NULL;
+	power_zone->zone_attr_count = count;
+}
+
+static void powercap_release(struct device *dev)
+{
+	bool allocated;
+
+	if (dev->parent) {
+		struct powercap_zone *power_zone = to_powercap_zone(dev);
+
+		/* Store flag as the release() may free memory */
+		allocated = power_zone->allocated;
+		/* Remove id from parent idr struct */
+		idr_remove(power_zone->parent_idr, power_zone->id);
+		/* Destroy idrs allocated for this zone */
+		idr_destroy(&power_zone->idr);
+		kfree(power_zone->name);
+		kfree(power_zone->zone_dev_attrs);
+		kfree(power_zone->constraints);
+		if (power_zone->ops->release)
+			power_zone->ops->release(power_zone);
+		if (allocated)
+			kfree(power_zone);
+	} else {
+		struct powercap_control_type *control_type =
+						to_powercap_control_type(dev);
+
+		/* Store flag as the release() may free memory */
+		allocated = control_type->allocated;
+		idr_destroy(&control_type->idr);
+		mutex_destroy(&control_type->lock);
+		if (control_type->ops && control_type->ops->release)
+			control_type->ops->release(control_type);
+		if (allocated)
+			kfree(control_type);
+	}
+}
+
+static ssize_t enabled_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	bool mode = true;
+
+	/* Default is enabled */
+	if (dev->parent) {
+		struct powercap_zone *power_zone = to_powercap_zone(dev);
+		if (power_zone->ops->get_enable)
+			if (power_zone->ops->get_enable(power_zone, &mode))
+				mode = false;
+	} else {
+		struct powercap_control_type *control_type =
+						to_powercap_control_type(dev);
+		if (control_type->ops && control_type->ops->get_enable)
+			if (control_type->ops->get_enable(control_type, &mode))
+				mode = false;
+	}
+
+	return sprintf(buf, "%d\n", mode);
+}
+
+static ssize_t enabled_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf,  size_t len)
+{
+	bool mode;
+
+	if (strtobool(buf, &mode))
+		return -EINVAL;
+	if (dev->parent) {
+		struct powercap_zone *power_zone = to_powercap_zone(dev);
+		if (power_zone->ops->set_enable)
+			if (!power_zone->ops->set_enable(power_zone, mode))
+				return len;
+	} else {
+		struct powercap_control_type *control_type =
+						to_powercap_control_type(dev);
+		if (control_type->ops && control_type->ops->set_enable)
+			if (!control_type->ops->set_enable(control_type, mode))
+				return len;
+	}
+
+	return -ENOSYS;
+}
+
+static DEVICE_ATTR_RW(enabled);
+
+static struct attribute *powercap_attrs[] = {
+	&dev_attr_enabled.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(powercap);
+
+static struct class powercap_class = {
+	.name = "powercap",
+	.dev_release = powercap_release,
+	.dev_groups = powercap_groups,
+};
+
+struct powercap_zone *powercap_register_zone(
+				struct powercap_zone *power_zone,
+				struct powercap_control_type *control_type,
+				const char *name,
+				struct powercap_zone *parent,
+				const struct powercap_zone_ops *ops,
+				int nr_constraints,
+				struct powercap_zone_constraint_ops *const_ops)
+{
+	int result;
+	int nr_attrs;
+
+	if (!name || !control_type || !ops ||
+			nr_constraints > MAX_CONSTRAINTS_PER_ZONE ||
+			(!ops->get_energy_uj && !ops->get_power_uw) ||
+			!control_type_valid(control_type))
+		return ERR_PTR(-EINVAL);
+
+	if (power_zone) {
+		if (!ops->release)
+			return ERR_PTR(-EINVAL);
+		memset(power_zone, 0, sizeof(*power_zone));
+	} else {
+		power_zone = kzalloc(sizeof(*power_zone), GFP_KERNEL);
+		if (!power_zone)
+			return ERR_PTR(-ENOMEM);
+		power_zone->allocated = true;
+	}
+	power_zone->ops = ops;
+	power_zone->control_type_inst = control_type;
+	if (!parent) {
+		power_zone->dev.parent = &control_type->dev;
+		power_zone->parent_idr = &control_type->idr;
+	} else {
+		power_zone->dev.parent = &parent->dev;
+		power_zone->parent_idr = &parent->idr;
+	}
+	power_zone->dev.class = &powercap_class;
+
+	mutex_lock(&control_type->lock);
+	/* Using idr to get the unique id */
+	result = idr_alloc(power_zone->parent_idr, NULL, 0, 0, GFP_KERNEL);
+	if (result < 0)
+		goto err_idr_alloc;
+
+	power_zone->id = result;
+	idr_init(&power_zone->idr);
+	power_zone->name = kstrdup(name, GFP_KERNEL);
+	if (!power_zone->name)
+		goto err_name_alloc;
+	dev_set_name(&power_zone->dev, "%s:%x",
+					dev_name(power_zone->dev.parent),
+					power_zone->id);
+	power_zone->constraints = kzalloc(sizeof(*power_zone->constraints) *
+					 nr_constraints, GFP_KERNEL);
+	if (!power_zone->constraints)
+		goto err_const_alloc;
+
+	nr_attrs = nr_constraints * POWERCAP_CONSTRAINTS_ATTRS +
+						POWERCAP_ZONE_MAX_ATTRS + 1;
+	power_zone->zone_dev_attrs = kzalloc(sizeof(void *) *
+						nr_attrs, GFP_KERNEL);
+	if (!power_zone->zone_dev_attrs)
+		goto err_attr_alloc;
+	create_power_zone_common_attributes(power_zone);
+	result = create_constraints(power_zone, nr_constraints, const_ops);
+	if (result)
+		goto err_dev_ret;
+
+	power_zone->zone_dev_attrs[power_zone->zone_attr_count] = NULL;
+	power_zone->dev_zone_attr_group.attrs = power_zone->zone_dev_attrs;
+	power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group;
+	power_zone->dev_attr_groups[1] = NULL;
+	power_zone->dev.groups = power_zone->dev_attr_groups;
+	result = device_register(&power_zone->dev);
+	if (result)
+		goto err_dev_ret;
+
+	control_type->nr_zones++;
+	mutex_unlock(&control_type->lock);
+
+	return power_zone;
+
+err_dev_ret:
+	kfree(power_zone->zone_dev_attrs);
+err_attr_alloc:
+	kfree(power_zone->constraints);
+err_const_alloc:
+	kfree(power_zone->name);
+err_name_alloc:
+	idr_remove(power_zone->parent_idr, power_zone->id);
+err_idr_alloc:
+	if (power_zone->allocated)
+		kfree(power_zone);
+	mutex_unlock(&control_type->lock);
+
+	return ERR_PTR(result);
+}
+EXPORT_SYMBOL_GPL(powercap_register_zone);
+
+int powercap_unregister_zone(struct powercap_control_type *control_type,
+				struct powercap_zone *power_zone)
+{
+	if (!power_zone || !control_type)
+		return -EINVAL;
+
+	mutex_lock(&control_type->lock);
+	control_type->nr_zones--;
+	mutex_unlock(&control_type->lock);
+
+	device_unregister(&power_zone->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(powercap_unregister_zone);
+
+struct powercap_control_type *powercap_register_control_type(
+				struct powercap_control_type *control_type,
+				const char *name,
+				const struct powercap_control_type_ops *ops)
+{
+	int result;
+
+	if (!name)
+		return ERR_PTR(-EINVAL);
+	if (control_type) {
+		if (!ops || !ops->release)
+			return ERR_PTR(-EINVAL);
+		memset(control_type, 0, sizeof(*control_type));
+	} else {
+		control_type = kzalloc(sizeof(*control_type), GFP_KERNEL);
+		if (!control_type)
+			return ERR_PTR(-ENOMEM);
+		control_type->allocated = true;
+	}
+	mutex_init(&control_type->lock);
+	control_type->ops = ops;
+	INIT_LIST_HEAD(&control_type->node);
+	control_type->dev.class = &powercap_class;
+	dev_set_name(&control_type->dev, "%s", name);
+	result = device_register(&control_type->dev);
+	if (result) {
+		if (control_type->allocated)
+			kfree(control_type);
+		return ERR_PTR(result);
+	}
+	idr_init(&control_type->idr);
+
+	mutex_lock(&powercap_cntrl_list_lock);
+	list_add_tail(&control_type->node, &powercap_cntrl_list);
+	mutex_unlock(&powercap_cntrl_list_lock);
+
+	return control_type;
+}
+EXPORT_SYMBOL_GPL(powercap_register_control_type);
+
+int powercap_unregister_control_type(struct powercap_control_type *control_type)
+{
+	struct powercap_control_type *pos = NULL;
+
+	if (control_type->nr_zones) {
+		dev_err(&control_type->dev, "Zones of this type still not freed\n");
+		return -EINVAL;
+	}
+	mutex_lock(&powercap_cntrl_list_lock);
+	list_for_each_entry(pos, &powercap_cntrl_list, node) {
+		if (pos == control_type) {
+			list_del(&control_type->node);
+			mutex_unlock(&powercap_cntrl_list_lock);
+			device_unregister(&control_type->dev);
+			return 0;
+		}
+	}
+	mutex_unlock(&powercap_cntrl_list_lock);
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(powercap_unregister_control_type);
+
+static int __init powercap_init(void)
+{
+	int result = 0;
+
+	result = seed_constraint_attributes();
+	if (result)
+		return result;
+
+	result = class_register(&powercap_class);
+
+	return result;
+}
+
+device_initcall(powercap_init);
+
+MODULE_DESCRIPTION("PowerCap sysfs Driver");
+MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
+MODULE_LICENSE("GPL v2");