diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index de03ca5..bf86b03 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -232,7 +232,8 @@
 #define H_GET_EM_PARMS		0x2B8
 #define H_SET_MPP		0x2D0
 #define H_GET_MPP		0x2D4
-#define MAX_HCALL_OPCODE	H_GET_MPP
+#define H_BEST_ENERGY		0x2F4
+#define MAX_HCALL_OPCODE	H_BEST_ENERGY
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 3139814..5d1b743 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -33,6 +33,16 @@
        depends on PCI_MSI && EEH
        default y
 
+config PSERIES_ENERGY
+	tristate "pSeries energy management capabilities driver"
+	depends on PPC_PSERIES
+	default y
+	help
+	  Provides interface to platform energy management capabilities
+	  on supported PSERIES platforms.
+	  Provides: /sys/devices/system/cpu/pseries_(de)activation_hint_list
+	  and /sys/devices/system/cpu/cpuN/pseries_(de)activation_hint
+
 config SCANLOG
 	tristate "Scanlog dump interface"
 	depends on RTAS_PROC && PPC_PSERIES
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 59eb8bd..fc52378 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -11,6 +11,7 @@
 obj-$(CONFIG_KEXEC)	+= kexec.o
 obj-$(CONFIG_PCI)	+= pci.o pci_dlpar.o
 obj-$(CONFIG_PSERIES_MSI)	+= msi.o
+obj-$(CONFIG_PSERIES_ENERGY)	+= pseries_energy.o
 
 obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu.o
 obj-$(CONFIG_MEMORY_HOTPLUG)	+= hotplug-memory.o
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
new file mode 100644
index 0000000..c8b3c69
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -0,0 +1,326 @@
+/*
+ * POWER platform energy management driver
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This pseries platform device driver provides access to
+ * platform energy management capabilities.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <asm/cputhreads.h>
+#include <asm/page.h>
+#include <asm/hvcall.h>
+
+
+#define MODULE_VERS "1.0"
+#define MODULE_NAME "pseries_energy"
+
+/* Driver flags */
+
+static int sysfs_entries;
+
+/* Helper routines */
+
+/*
+ * Routine to detect firmware support for hcall
+ * return 1 if H_BEST_ENERGY is supported
+ * else return 0
+ */
+
+static int check_for_h_best_energy(void)
+{
+	struct device_node *rtas = NULL;
+	const char *hypertas, *s;
+	int length;
+	int rc = 0;
+
+	rtas = of_find_node_by_path("/rtas");
+	if (!rtas)
+		return 0;
+
+	hypertas = of_get_property(rtas, "ibm,hypertas-functions", &length);
+	if (!hypertas) {
+		of_node_put(rtas);
+		return 0;
+	}
+
+	/* hypertas will have list of strings with hcall names */
+	for (s = hypertas; s < hypertas + length; s += strlen(s) + 1) {
+		if (!strncmp("hcall-best-energy-1", s, 19)) {
+			rc = 1; /* Found the string */
+			break;
+		}
+	}
+	of_node_put(rtas);
+	return rc;
+}
+
+/* Helper Routines to convert between drc_index to cpu numbers */
+
+static u32 cpu_to_drc_index(int cpu)
+{
+	struct device_node *dn = NULL;
+	const int *indexes;
+	int i;
+	int rc = 1;
+	u32 ret = 0;
+
+	dn = of_find_node_by_path("/cpus");
+	if (dn == NULL)
+		goto err;
+	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
+	if (indexes == NULL)
+		goto err_of_node_put;
+	/* Convert logical cpu number to core number */
+	i = cpu_core_index_of_thread(cpu);
+	/*
+	 * The first element indexes[0] is the number of drc_indexes
+	 * returned in the list.  Hence i+1 will get the drc_index
+	 * corresponding to core number i.
+	 */
+	WARN_ON(i > indexes[0]);
+	ret = indexes[i + 1];
+	rc = 0;
+
+err_of_node_put:
+	of_node_put(dn);
+err:
+	if (rc)
+		printk(KERN_WARNING "cpu_to_drc_index(%d) failed", cpu);
+	return ret;
+}
+
+static int drc_index_to_cpu(u32 drc_index)
+{
+	struct device_node *dn = NULL;
+	const int *indexes;
+	int i, cpu = 0;
+	int rc = 1;
+
+	dn = of_find_node_by_path("/cpus");
+	if (dn == NULL)
+		goto err;
+	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
+	if (indexes == NULL)
+		goto err_of_node_put;
+	/*
+	 * First element in the array is the number of drc_indexes
+	 * returned.  Search through the list to find the matching
+	 * drc_index and get the core number
+	 */
+	for (i = 0; i < indexes[0]; i++) {
+		if (indexes[i + 1] == drc_index)
+			break;
+	}
+	/* Convert core number to logical cpu number */
+	cpu = cpu_first_thread_of_core(i);
+	rc = 0;
+
+err_of_node_put:
+	of_node_put(dn);
+err:
+	if (rc)
+		printk(KERN_WARNING "drc_index_to_cpu(%d) failed", drc_index);
+	return cpu;
+}
+
+/*
+ * pseries hypervisor call H_BEST_ENERGY provides hints to OS on
+ * preferred logical cpus to activate or deactivate for optimized
+ * energy consumption.
+ */
+
+#define FLAGS_MODE1	0x004E200000080E01
+#define FLAGS_MODE2	0x004E200000080401
+#define FLAGS_ACTIVATE  0x100
+
+static ssize_t get_best_energy_list(char *page, int activate)
+{
+	int rc, cnt, i, cpu;
+	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
+	unsigned long flags = 0;
+	u32 *buf_page;
+	char *s = page;
+
+	buf_page = (u32 *) get_zeroed_page(GFP_KERNEL);
+	if (!buf_page)
+		return -ENOMEM;
+
+	flags = FLAGS_MODE1;
+	if (activate)
+		flags |= FLAGS_ACTIVATE;
+
+	rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags, 0, __pa(buf_page),
+				0, 0, 0, 0, 0, 0);
+	if (rc != H_SUCCESS) {
+		free_page((unsigned long) buf_page);
+		return -EINVAL;
+	}
+
+	cnt = retbuf[0];
+	for (i = 0; i < cnt; i++) {
+		cpu = drc_index_to_cpu(buf_page[2*i+1]);
+		if ((cpu_online(cpu) && !activate) ||
+		    (!cpu_online(cpu) && activate))
+			s += sprintf(s, "%d,", cpu);
+	}
+	if (s > page) { /* Something to show */
+		s--; /* Suppress last comma */
+		s += sprintf(s, "\n");
+	}
+
+	free_page((unsigned long) buf_page);
+	return s-page;
+}
+
+static ssize_t get_best_energy_data(struct sys_device *dev,
+					char *page, int activate)
+{
+	int rc;
+	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
+	unsigned long flags = 0;
+
+	flags = FLAGS_MODE2;
+	if (activate)
+		flags |= FLAGS_ACTIVATE;
+
+	rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags,
+				cpu_to_drc_index(dev->id),
+				0, 0, 0, 0, 0, 0, 0);
+
+	if (rc != H_SUCCESS)
+		return -EINVAL;
+
+	return sprintf(page, "%lu\n", retbuf[1] >> 32);
+}
+
+/* Wrapper functions */
+
+static ssize_t cpu_activate_hint_list_show(struct sysdev_class *class,
+			struct sysdev_class_attribute *attr, char *page)
+{
+	return get_best_energy_list(page, 1);
+}
+
+static ssize_t cpu_deactivate_hint_list_show(struct sysdev_class *class,
+			struct sysdev_class_attribute *attr, char *page)
+{
+	return get_best_energy_list(page, 0);
+}
+
+static ssize_t percpu_activate_hint_show(struct sys_device *dev,
+			struct sysdev_attribute *attr, char *page)
+{
+	return get_best_energy_data(dev, page, 1);
+}
+
+static ssize_t percpu_deactivate_hint_show(struct sys_device *dev,
+			struct sysdev_attribute *attr, char *page)
+{
+	return get_best_energy_data(dev, page, 0);
+}
+
+/*
+ * Create sysfs interface:
+ * /sys/devices/system/cpu/pseries_activate_hint_list
+ * /sys/devices/system/cpu/pseries_deactivate_hint_list
+ *	Comma separated list of cpus to activate or deactivate
+ * /sys/devices/system/cpu/cpuN/pseries_activate_hint
+ * /sys/devices/system/cpu/cpuN/pseries_deactivate_hint
+ *	Per-cpu value of the hint
+ */
+
+struct sysdev_class_attribute attr_cpu_activate_hint_list =
+		_SYSDEV_CLASS_ATTR(pseries_activate_hint_list, 0444,
+		cpu_activate_hint_list_show, NULL);
+
+struct sysdev_class_attribute attr_cpu_deactivate_hint_list =
+		_SYSDEV_CLASS_ATTR(pseries_deactivate_hint_list, 0444,
+		cpu_deactivate_hint_list_show, NULL);
+
+struct sysdev_attribute attr_percpu_activate_hint =
+		_SYSDEV_ATTR(pseries_activate_hint, 0444,
+		percpu_activate_hint_show, NULL);
+
+struct sysdev_attribute attr_percpu_deactivate_hint =
+		_SYSDEV_ATTR(pseries_deactivate_hint, 0444,
+		percpu_deactivate_hint_show, NULL);
+
+static int __init pseries_energy_init(void)
+{
+	int cpu, err;
+	struct sys_device *cpu_sys_dev;
+
+	if (!check_for_h_best_energy()) {
+		printk(KERN_INFO "Hypercall H_BEST_ENERGY not supported\n");
+		return 0;
+	}
+	/* Create the sysfs files */
+	err = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
+				&attr_cpu_activate_hint_list.attr);
+	if (!err)
+		err = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
+				&attr_cpu_deactivate_hint_list.attr);
+
+	if (err)
+		return err;
+	for_each_possible_cpu(cpu) {
+		cpu_sys_dev = get_cpu_sysdev(cpu);
+		err = sysfs_create_file(&cpu_sys_dev->kobj,
+				&attr_percpu_activate_hint.attr);
+		if (err)
+			break;
+		err = sysfs_create_file(&cpu_sys_dev->kobj,
+				&attr_percpu_deactivate_hint.attr);
+		if (err)
+			break;
+	}
+
+	if (err)
+		return err;
+
+	sysfs_entries = 1; /* Removed entries on cleanup */
+	return 0;
+
+}
+
+static void __exit pseries_energy_cleanup(void)
+{
+	int cpu;
+	struct sys_device *cpu_sys_dev;
+
+	if (!sysfs_entries)
+		return;
+
+	/* Remove the sysfs files */
+	sysfs_remove_file(&cpu_sysdev_class.kset.kobj,
+				&attr_cpu_activate_hint_list.attr);
+
+	sysfs_remove_file(&cpu_sysdev_class.kset.kobj,
+				&attr_cpu_deactivate_hint_list.attr);
+
+	for_each_possible_cpu(cpu) {
+		cpu_sys_dev = get_cpu_sysdev(cpu);
+		sysfs_remove_file(&cpu_sys_dev->kobj,
+				&attr_percpu_activate_hint.attr);
+		sysfs_remove_file(&cpu_sys_dev->kobj,
+				&attr_percpu_deactivate_hint.attr);
+	}
+}
+
+module_init(pseries_energy_init);
+module_exit(pseries_energy_cleanup);
+MODULE_DESCRIPTION("Driver for pSeries platform energy management");
+MODULE_AUTHOR("Vaidyanathan Srinivasan");
+MODULE_LICENSE("GPL");