Merge branch 'pm-cpufreq'

* pm-cpufreq: (55 commits)
  cpufreq / intel_pstate: Fix 32 bit build
  cpufreq: conservative: Fix typos in comments
  cpufreq: ondemand: Fix typos in comments
  cpufreq: exynos: simplify .init() for setting policy->cpus
  cpufreq: kirkwood: Add a cpufreq driver for Marvell Kirkwood SoCs
  cpufreq/x86: Add P-state driver for sandy bridge.
  cpufreq_stats: do not remove sysfs files if frequency table is not present
  cpufreq: Do not track governor name for scaling drivers with internal governors.
  cpufreq: Only call cpufreq_out_of_sync() for driver that implement cpufreq_driver.target()
  cpufreq: Retrieve current frequency from scaling drivers with internal governors
  cpufreq: Fix locking issues
  cpufreq: Create a macro for unlock_policy_rwsem{read,write}
  cpufreq: Remove unused HOTPLUG_CPU code
  cpufreq: governors: Fix WARN_ON() for multi-policy platforms
  cpufreq: ondemand: Replace down_differential tuner with adj_up_threshold
  cpufreq / stats: Get rid of CPUFREQ_STATDEVICE_ATTR
  cpufreq: Don't check cpu_online(policy->cpu)
  cpufreq: add imx6q-cpufreq driver
  cpufreq: Don't remove sysfs link for policy->cpu
  cpufreq: Remove unnecessary use of policy->shared_type
  ...

32 files changed, 2287 insertions, 423 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index f5fb0722a63a..2b4e89ba15ad 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -134,6 +134,8 @@ source "drivers/hwspinlock/Kconfig"
 
 source "drivers/clocksource/Kconfig"
 
+source "drivers/mailbox/Kconfig"
+
 source "drivers/iommu/Kconfig"
 
 source "drivers/remoteproc/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 7863b9fee50b..a8d32f1094b4 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -130,6 +130,7 @@ obj-y				+= platform/
 #common clk code
 obj-y				+= clk/
 
+obj-$(CONFIG_MAILBOX)		+= mailbox/
 obj-$(CONFIG_HWSPINLOCK)	+= hwspinlock/
 obj-$(CONFIG_NFC)		+= nfc/
 obj-$(CONFIG_IOMMU_SUPPORT)	+= iommu/
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 50b2831e027d..32ee0fc7ea54 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -162,7 +162,7 @@ unsigned long opp_get_voltage(struct opp *opp)
 
 	return v;
 }
-EXPORT_SYMBOL(opp_get_voltage);
+EXPORT_SYMBOL_GPL(opp_get_voltage);
 
 /**
  * opp_get_freq() - Gets the frequency corresponding to an available opp
@@ -192,7 +192,7 @@ unsigned long opp_get_freq(struct opp *opp)
 
 	return f;
 }
-EXPORT_SYMBOL(opp_get_freq);
+EXPORT_SYMBOL_GPL(opp_get_freq);
 
 /**
  * opp_get_opp_count() - Get number of opps available in the opp list
@@ -225,7 +225,7 @@ int opp_get_opp_count(struct device *dev)
 
 	return count;
 }
-EXPORT_SYMBOL(opp_get_opp_count);
+EXPORT_SYMBOL_GPL(opp_get_opp_count);
 
 /**
  * opp_find_freq_exact() - search for an exact frequency
@@ -276,7 +276,7 @@ struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq,
 
 	return opp;
 }
-EXPORT_SYMBOL(opp_find_freq_exact);
+EXPORT_SYMBOL_GPL(opp_find_freq_exact);
 
 /**
  * opp_find_freq_ceil() - Search for an rounded ceil freq
@@ -323,7 +323,7 @@ struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq)
 
 	return opp;
 }
-EXPORT_SYMBOL(opp_find_freq_ceil);
+EXPORT_SYMBOL_GPL(opp_find_freq_ceil);
 
 /**
  * opp_find_freq_floor() - Search for a rounded floor freq
@@ -374,7 +374,7 @@ struct opp *opp_find_freq_floor(struct device *dev, unsigned long *freq)
 
 	return opp;
 }
-EXPORT_SYMBOL(opp_find_freq_floor);
+EXPORT_SYMBOL_GPL(opp_find_freq_floor);
 
 /**
  * opp_add()  - Add an OPP table from a table definitions
@@ -568,7 +568,7 @@ int opp_enable(struct device *dev, unsigned long freq)
 {
 	return opp_set_availability(dev, freq, true);
 }
-EXPORT_SYMBOL(opp_enable);
+EXPORT_SYMBOL_GPL(opp_enable);
 
 /**
  * opp_disable() - Disable a specific OPP
@@ -590,7 +590,7 @@ int opp_disable(struct device *dev, unsigned long freq)
 {
 	return opp_set_availability(dev, freq, false);
 }
-EXPORT_SYMBOL(opp_disable);
+EXPORT_SYMBOL_GPL(opp_disable);
 
 #ifdef CONFIG_CPU_FREQ
 /**
@@ -661,6 +661,7 @@ int opp_init_cpufreq_table(struct device *dev,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(opp_init_cpufreq_table);
 
 /**
  * opp_free_cpufreq_table() - free the cpufreq table
@@ -678,6 +679,7 @@ void opp_free_cpufreq_table(struct device *dev,
 	kfree(*table);
 	*table = NULL;
 }
+EXPORT_SYMBOL_GPL(opp_free_cpufreq_table);
 #endif		/* CONFIG_CPU_FREQ */
 
 /**
@@ -738,4 +740,5 @@ int of_init_opp_table(struct device *dev)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(of_init_opp_table);
 #endif
diff --git a/drivers/clk/clk-highbank.c b/drivers/clk/clk-highbank.c
index 52fecadf004a..3a0b723da2bc 100644
--- a/drivers/clk/clk-highbank.c
+++ b/drivers/clk/clk-highbank.c
@@ -182,8 +182,10 @@ static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
 		reg |= HB_PLL_EXT_ENA;
 		reg &= ~HB_PLL_EXT_BYPASS;
 	} else {
+		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 		reg &= ~HB_PLL_DIVQ_MASK;
 		reg |= divq << HB_PLL_DIVQ_SHIFT;
+		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 	}
 	writel(reg, hbclk->reg);
 
diff --git a/drivers/clk/mvebu/clk-gating-ctrl.c b/drivers/clk/mvebu/clk-gating-ctrl.c
index 8fa5408b6c7d..ebf141d4374b 100644
--- a/drivers/clk/mvebu/clk-gating-ctrl.c
+++ b/drivers/clk/mvebu/clk-gating-ctrl.c
@@ -193,6 +193,7 @@ static const struct mvebu_soc_descr __initconst kirkwood_gating_descr[] = {
 	{ "runit", NULL, 7 },
 	{ "xor0", NULL, 8 },
 	{ "audio", NULL, 9 },
+	{ "powersave", "cpuclk", 11 },
 	{ "sata0", NULL, 14 },
 	{ "sata1", NULL, 15 },
 	{ "xor1", NULL, 16 },
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index e0a899f25e37..cbcb21e32771 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -185,7 +185,7 @@ config CPU_FREQ_GOV_CONSERVATIVE
 	  If in doubt, say N.
 
 config GENERIC_CPUFREQ_CPU0
-	bool "Generic CPU0 cpufreq driver"
+	tristate "Generic CPU0 cpufreq driver"
 	depends on HAVE_CLK && REGULATOR && PM_OPP && OF
 	select CPU_FREQ_TABLE
 	help
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index a0b3661d90b0..7f333af1c059 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -77,9 +77,39 @@ config ARM_EXYNOS5250_CPUFREQ
 	  This adds the CPUFreq driver for Samsung EXYNOS5250
 	  SoC.
 
+config ARM_KIRKWOOD_CPUFREQ
+	def_bool ARCH_KIRKWOOD && OF
+	help
+	  This adds the CPUFreq driver for Marvell Kirkwood
+	  SoCs.
+
+config ARM_IMX6Q_CPUFREQ
+	tristate "Freescale i.MX6Q cpufreq support"
+	depends on SOC_IMX6Q
+	depends on REGULATOR_ANATOP
+	help
+	  This adds cpufreq driver support for Freescale i.MX6Q SOC.
+
+	  If in doubt, say N.
+
 config ARM_SPEAR_CPUFREQ
 	bool "SPEAr CPUFreq support"
 	depends on PLAT_SPEAR
 	default y
 	help
 	  This adds the CPUFreq driver support for SPEAr SOCs.
+
+config ARM_HIGHBANK_CPUFREQ
+	tristate "Calxeda Highbank-based"
+	depends on ARCH_HIGHBANK
+	select CPU_FREQ_TABLE
+	select GENERIC_CPUFREQ_CPU0
+	select PM_OPP
+	select REGULATOR
+
+	default m
+	help
+	  This adds the CPUFreq driver for Calxeda Highbank SoC
+	  based boards.
+
+	  If in doubt, say N.
diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86
index 7227cd734042..6aa7053ce2ef 100644
--- a/drivers/cpufreq/Kconfig.x86
+++ b/drivers/cpufreq/Kconfig.x86
@@ -2,6 +2,24 @@
 # x86 CPU Frequency scaling drivers
 #
 
+config X86_INTEL_PSTATE
+       tristate "Intel P state control"
+       depends on X86
+       help
+          This driver provides a P state for Intel core processors.
+	  The driver implements an internal governor and will become
+          the scaling driver and governor for Sandy bridge processors.
+
+	  When this driver is enabled it will become the perferred
+          scaling driver for Sandy bridge processors.
+
+	  Note: This driver should be built with the same settings as
+	  the other scaling drivers configured into the system
+	  (module/built-in) in order for the driver to register itself
+	  as the scaling driver on the system.
+
+	  If in doubt, say N.
+
 config X86_PCC_CPUFREQ
 	tristate "Processor Clocking Control interface driver"
 	depends on ACPI && ACPI_PROCESSOR
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index fadc4d496e2f..5399c45ac311 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -19,11 +19,12 @@ obj-$(CONFIG_GENERIC_CPUFREQ_CPU0)	+= cpufreq-cpu0.o
 ##################################################################################
 # x86 drivers.
 # Link order matters. K8 is preferred to ACPI because of firmware bugs in early
-# K8 systems. ACPI is preferred to all other hardware-specific drivers.
+# K8 systems. This is still the case but acpi-cpufreq errors out so that
+# powernow-k8 can load then. ACPI is preferred to all other hardware-specific drivers.
 # speedstep-* is preferred over p4-clockmod.
 
-obj-$(CONFIG_X86_POWERNOW_K8)		+= powernow-k8.o
 obj-$(CONFIG_X86_ACPI_CPUFREQ)		+= acpi-cpufreq.o mperf.o
+obj-$(CONFIG_X86_POWERNOW_K8)		+= powernow-k8.o
 obj-$(CONFIG_X86_PCC_CPUFREQ)		+= pcc-cpufreq.o
 obj-$(CONFIG_X86_POWERNOW_K6)		+= powernow-k6.o
 obj-$(CONFIG_X86_POWERNOW_K7)		+= powernow-k7.o
@@ -39,6 +40,7 @@ obj-$(CONFIG_X86_SPEEDSTEP_SMI)		+= speedstep-smi.o
 obj-$(CONFIG_X86_SPEEDSTEP_CENTRINO)	+= speedstep-centrino.o
 obj-$(CONFIG_X86_P4_CLOCKMOD)		+= p4-clockmod.o
 obj-$(CONFIG_X86_CPUFREQ_NFORCE2)	+= cpufreq-nforce2.o
+obj-$(CONFIG_X86_INTEL_PSTATE)		+= intel_pstate.o
 
 ##################################################################################
 # ARM SoC drivers
@@ -50,8 +52,11 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ)	+= exynos-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ)	+= exynos4210-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ)	+= exynos4x12-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ)	+= exynos5250-cpufreq.o
-obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)     += omap-cpufreq.o
+obj-$(CONFIG_ARM_KIRKWOOD_CPUFREQ)	+= kirkwood-cpufreq.o
+obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)	+= omap-cpufreq.o
 obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
+obj-$(CONFIG_ARM_HIGHBANK_CPUFREQ)	+= highbank-cpufreq.o
+obj-$(CONFIG_ARM_IMX6Q_CPUFREQ)		+= imx6q-cpufreq.o
 
 ##################################################################################
 # PowerPC platform drivers
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 7b0d49d78c61..937bc286591f 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -734,7 +734,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
 #ifdef CONFIG_SMP
 	dmi_check_system(sw_any_bug_dmi_table);
-	if (bios_with_sw_any_bug && cpumask_weight(policy->cpus) == 1) {
+	if (bios_with_sw_any_bug && !policy_is_shared(policy)) {
 		policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 		cpumask_copy(policy->cpus, cpu_core_mask(cpu));
 	}
@@ -762,6 +762,12 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
 	switch (perf->control_register.space_id) {
 	case ACPI_ADR_SPACE_SYSTEM_IO:
+		if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+		    boot_cpu_data.x86 == 0xf) {
+			pr_debug("AMD K8 systems must use native drivers.\n");
+			result = -ENODEV;
+			goto err_unreg;
+		}
 		pr_debug("SYSTEM IO addr space\n");
 		data->cpu_feature = SYSTEM_IO_CAPABLE;
 		break;
diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index debc5a7c8db6..4e5b7fb8927c 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -12,12 +12,12 @@
 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
 
 #include <linux/clk.h>
-#include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/opp.h>
+#include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 
@@ -146,7 +146,6 @@ static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
 	 * share the clock and voltage and clock.  Use cpufreq affected_cpus
 	 * interface to have all CPUs scaled together.
 	 */
-	policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 	cpumask_setall(policy->cpus);
 
 	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
@@ -177,34 +176,32 @@ static struct cpufreq_driver cpu0_cpufreq_driver = {
 	.attr = cpu0_cpufreq_attr,
 };
 
-static int cpu0_cpufreq_driver_init(void)
+static int cpu0_cpufreq_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
 	int ret;
 
-	np = of_find_node_by_path("/cpus/cpu@0");
+	for_each_child_of_node(of_find_node_by_path("/cpus"), np) {
+		if (of_get_property(np, "operating-points", NULL))
+			break;
+	}
+
 	if (!np) {
 		pr_err("failed to find cpu0 node\n");
 		return -ENOENT;
 	}
 
-	cpu_dev = get_cpu_device(0);
-	if (!cpu_dev) {
-		pr_err("failed to get cpu0 device\n");
-		ret = -ENODEV;
-		goto out_put_node;
-	}
-
+	cpu_dev = &pdev->dev;
 	cpu_dev->of_node = np;
 
-	cpu_clk = clk_get(cpu_dev, NULL);
+	cpu_clk = devm_clk_get(cpu_dev, NULL);
 	if (IS_ERR(cpu_clk)) {
 		ret = PTR_ERR(cpu_clk);
 		pr_err("failed to get cpu0 clock: %d\n", ret);
 		goto out_put_node;
 	}
 
-	cpu_reg = regulator_get(cpu_dev, "cpu0");
+	cpu_reg = devm_regulator_get(cpu_dev, "cpu0");
 	if (IS_ERR(cpu_reg)) {
 		pr_warn("failed to get cpu0 regulator\n");
 		cpu_reg = NULL;
@@ -267,7 +264,24 @@ out_put_node:
 	of_node_put(np);
 	return ret;
 }
-late_initcall(cpu0_cpufreq_driver_init);
+
+static int cpu0_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_driver(&cpu0_cpufreq_driver);
+	opp_free_cpufreq_table(cpu_dev, &freq_table);
+
+	return 0;
+}
+
+static struct platform_driver cpu0_cpufreq_platdrv = {
+	.driver = {
+		.name	= "cpufreq-cpu0",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= cpu0_cpufreq_probe,
+	.remove		= cpu0_cpufreq_remove,
+};
+module_platform_driver(cpu0_cpufreq_platdrv);
 
 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 99faadf454ec..b02824d092e7 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -59,8 +59,6 @@ static DEFINE_SPINLOCK(cpufreq_driver_lock);
  *   mode before doing so.
  *
  * Additional rules:
- * - All holders of the lock should check to make sure that the CPU they
- *   are concerned with are online after they get the lock.
  * - Governor routines that can be called in cpufreq hotplug path should not
  *   take this sem as top level hotplug notifier handler takes this.
  * - Lock should not be held across
@@ -70,38 +68,28 @@ static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
 
 #define lock_policy_rwsem(mode, cpu)					\
-static int lock_policy_rwsem_##mode					\
-(int cpu)								\
+static int lock_policy_rwsem_##mode(int cpu)				\
 {									\
 	int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);		\
 	BUG_ON(policy_cpu == -1);					\
 	down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu));		\
-	if (unlikely(!cpu_online(cpu))) {				\
-		up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu));	\
-		return -1;						\
-	}								\
 									\
 	return 0;							\
 }
 
 lock_policy_rwsem(read, cpu);
-
 lock_policy_rwsem(write, cpu);
 
-static void unlock_policy_rwsem_read(int cpu)
-{
-	int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
-	BUG_ON(policy_cpu == -1);
-	up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
-}
-
-static void unlock_policy_rwsem_write(int cpu)
-{
-	int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
-	BUG_ON(policy_cpu == -1);
-	up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
+#define unlock_policy_rwsem(mode, cpu)					\
+static void unlock_policy_rwsem_##mode(int cpu)				\
+{									\
+	int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);		\
+	BUG_ON(policy_cpu == -1);					\
+	up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu));		\
 }
 
+unlock_policy_rwsem(read, cpu);
+unlock_policy_rwsem(write, cpu);
 
 /* internal prototypes */
 static int __cpufreq_governor(struct cpufreq_policy *policy,
@@ -180,6 +168,9 @@ err_out:
 
 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
 {
+	if (cpufreq_disabled())
+		return NULL;
+
 	return __cpufreq_cpu_get(cpu, false);
 }
 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
@@ -198,6 +189,9 @@ static void __cpufreq_cpu_put(struct cpufreq_policy *data, bool sysfs)
 
 void cpufreq_cpu_put(struct cpufreq_policy *data)
 {
+	if (cpufreq_disabled())
+		return;
+
 	__cpufreq_cpu_put(data, false);
 }
 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
@@ -261,14 +255,21 @@ static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 {
 	struct cpufreq_policy *policy;
+	unsigned long flags;
 
 	BUG_ON(irqs_disabled());
 
+	if (cpufreq_disabled())
+		return;
+
 	freqs->flags = cpufreq_driver->flags;
 	pr_debug("notification %u of frequency transition to %u kHz\n",
 		state, freqs->new);
 
+	spin_lock_irqsave(&cpufreq_driver_lock, flags);
 	policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
+	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
 	switch (state) {
 
 	case CPUFREQ_PRECHANGE:
@@ -542,8 +543,6 @@ static ssize_t show_cpus(const struct cpumask *mask, char *buf)
  */
 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
 {
-	if (cpumask_empty(policy->related_cpus))
-		return show_cpus(policy->cpus, buf);
 	return show_cpus(policy->related_cpus, buf);
 }
 
@@ -699,87 +698,6 @@ static struct kobj_type ktype_cpufreq = {
 	.release	= cpufreq_sysfs_release,
 };
 
-/*
- * Returns:
- *   Negative: Failure
- *   0:        Success
- *   Positive: When we have a managed CPU and the sysfs got symlinked
- */
-static int cpufreq_add_dev_policy(unsigned int cpu,
-				  struct cpufreq_policy *policy,
-				  struct device *dev)
-{
-	int ret = 0;
-#ifdef CONFIG_SMP
-	unsigned long flags;
-	unsigned int j;
-#ifdef CONFIG_HOTPLUG_CPU
-	struct cpufreq_governor *gov;
-
-	gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
-	if (gov) {
-		policy->governor = gov;
-		pr_debug("Restoring governor %s for cpu %d\n",
-		       policy->governor->name, cpu);
-	}
-#endif
-
-	for_each_cpu(j, policy->cpus) {
-		struct cpufreq_policy *managed_policy;
-
-		if (cpu == j)
-			continue;
-
-		/* Check for existing affected CPUs.
-		 * They may not be aware of it due to CPU Hotplug.
-		 * cpufreq_cpu_put is called when the device is removed
-		 * in __cpufreq_remove_dev()
-		 */
-		managed_policy = cpufreq_cpu_get(j);
-		if (unlikely(managed_policy)) {
-
-			/* Set proper policy_cpu */
-			unlock_policy_rwsem_write(cpu);
-			per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
-
-			if (lock_policy_rwsem_write(cpu) < 0) {
-				/* Should not go through policy unlock path */
-				if (cpufreq_driver->exit)
-					cpufreq_driver->exit(policy);
-				cpufreq_cpu_put(managed_policy);
-				return -EBUSY;
-			}
-
-			spin_lock_irqsave(&cpufreq_driver_lock, flags);
-			cpumask_copy(managed_policy->cpus, policy->cpus);
-			per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
-			spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
-			pr_debug("CPU already managed, adding link\n");
-			ret = sysfs_create_link(&dev->kobj,
-						&managed_policy->kobj,
-						"cpufreq");
-			if (ret)
-				cpufreq_cpu_put(managed_policy);
-			/*
-			 * Success. We only needed to be added to the mask.
-			 * Call driver->exit() because only the cpu parent of
-			 * the kobj needed to call init().
-			 */
-			if (cpufreq_driver->exit)
-				cpufreq_driver->exit(policy);
-
-			if (!ret)
-				return 1;
-			else
-				return ret;
-		}
-	}
-#endif
-	return ret;
-}
-
-
 /* symlink affected CPUs */
 static int cpufreq_add_dev_symlink(unsigned int cpu,
 				   struct cpufreq_policy *policy)
@@ -793,8 +711,6 @@ static int cpufreq_add_dev_symlink(unsigned int cpu,
 
 		if (j == cpu)
 			continue;
-		if (!cpu_online(j))
-			continue;
 
 		pr_debug("CPU %u already managed, adding link\n", j);
 		managed_policy = cpufreq_cpu_get(cpu);
@@ -851,8 +767,6 @@ static int cpufreq_add_dev_interface(unsigned int cpu,
 
 	spin_lock_irqsave(&cpufreq_driver_lock, flags);
 	for_each_cpu(j, policy->cpus) {
-		if (!cpu_online(j))
-			continue;
 		per_cpu(cpufreq_cpu_data, j) = policy;
 		per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
 	}
@@ -884,6 +798,42 @@ err_out_kobj_put:
 	return ret;
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
+				  struct device *dev)
+{
+	struct cpufreq_policy *policy;
+	int ret = 0;
+	unsigned long flags;
+
+	policy = cpufreq_cpu_get(sibling);
+	WARN_ON(!policy);
+
+	__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+
+	lock_policy_rwsem_write(sibling);
+
+	spin_lock_irqsave(&cpufreq_driver_lock, flags);
+
+	cpumask_set_cpu(cpu, policy->cpus);
+	per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu;
+	per_cpu(cpufreq_cpu_data, cpu) = policy;
+	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+	unlock_policy_rwsem_write(sibling);
+
+	__cpufreq_governor(policy, CPUFREQ_GOV_START);
+	__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+
+	ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
+	if (ret) {
+		cpufreq_cpu_put(policy);
+		return ret;
+	}
+
+	return 0;
+}
+#endif
 
 /**
  * cpufreq_add_dev - add a CPU device
@@ -896,12 +846,12 @@ err_out_kobj_put:
  */
 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 {
-	unsigned int cpu = dev->id;
-	int ret = 0, found = 0;
+	unsigned int j, cpu = dev->id;
+	int ret = -ENOMEM;
 	struct cpufreq_policy *policy;
 	unsigned long flags;
-	unsigned int j;
 #ifdef CONFIG_HOTPLUG_CPU
+	struct cpufreq_governor *gov;
 	int sibling;
 #endif
 
@@ -918,6 +868,19 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 		cpufreq_cpu_put(policy);
 		return 0;
 	}
+
+#ifdef CONFIG_HOTPLUG_CPU
+	/* Check if this cpu was hot-unplugged earlier and has siblings */
+	spin_lock_irqsave(&cpufreq_driver_lock, flags);
+	for_each_online_cpu(sibling) {
+		struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
+		if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) {
+			spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
+			return cpufreq_add_policy_cpu(cpu, sibling, dev);
+		}
+	}
+	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
+#endif
 #endif
 
 	if (!try_module_get(cpufreq_driver->owner)) {
@@ -925,7 +888,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 		goto module_out;
 	}
 
-	ret = -ENOMEM;
 	policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
 	if (!policy)
 		goto nomem_out;
@@ -937,66 +899,58 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 		goto err_free_cpumask;
 
 	policy->cpu = cpu;
+	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 	cpumask_copy(policy->cpus, cpumask_of(cpu));
 
 	/* Initially set CPU itself as the policy_cpu */
 	per_cpu(cpufreq_policy_cpu, cpu) = cpu;
-	ret = (lock_policy_rwsem_write(cpu) < 0);
-	WARN_ON(ret);
 
 	init_completion(&policy->kobj_unregister);
 	INIT_WORK(&policy->update, handle_update);
 
-	/* Set governor before ->init, so that driver could check it */
-#ifdef CONFIG_HOTPLUG_CPU
-	for_each_online_cpu(sibling) {
-		struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
-		if (cp && cp->governor &&
-		    (cpumask_test_cpu(cpu, cp->related_cpus))) {
-			policy->governor = cp->governor;
-			found = 1;
-			break;
-		}
-	}
-#endif
-	if (!found)
-		policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 	/* call driver. From then on the cpufreq must be able
 	 * to accept all calls to ->verify and ->setpolicy for this CPU
 	 */
 	ret = cpufreq_driver->init(policy);
 	if (ret) {
 		pr_debug("initialization failed\n");
-		goto err_unlock_policy;
+		goto err_set_policy_cpu;
 	}
+
+	/* related cpus should atleast have policy->cpus */
+	cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
+
+	/*
+	 * affected cpus must always be the one, which are online. We aren't
+	 * managing offline cpus here.
+	 */
+	cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
+
 	policy->user_policy.min = policy->min;
 	policy->user_policy.max = policy->max;
 
 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
 				     CPUFREQ_START, policy);
 
-	ret = cpufreq_add_dev_policy(cpu, policy, dev);
-	if (ret) {
-		if (ret > 0)
-			/* This is a managed cpu, symlink created,
-			   exit with 0 */
-			ret = 0;
-		goto err_unlock_policy;
+#ifdef CONFIG_HOTPLUG_CPU
+	gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
+	if (gov) {
+		policy->governor = gov;
+		pr_debug("Restoring governor %s for cpu %d\n",
+		       policy->governor->name, cpu);
 	}
+#endif
 
 	ret = cpufreq_add_dev_interface(cpu, policy, dev);
 	if (ret)
 		goto err_out_unregister;
 
-	unlock_policy_rwsem_write(cpu);
-
 	kobject_uevent(&policy->kobj, KOBJ_ADD);
 	module_put(cpufreq_driver->owner);
 	pr_debug("initialization complete\n");
 
 	return 0;
 
-
 err_out_unregister:
 	spin_lock_irqsave(&cpufreq_driver_lock, flags);
 	for_each_cpu(j, policy->cpus)
@@ -1006,8 +960,8 @@ err_out_unregister:
 	kobject_put(&policy->kobj);
 	wait_for_completion(&policy->kobj_unregister);
 
-err_unlock_policy:
-	unlock_policy_rwsem_write(cpu);
+err_set_policy_cpu:
+	per_cpu(cpufreq_policy_cpu, cpu) = -1;
 	free_cpumask_var(policy->related_cpus);
 err_free_cpumask:
 	free_cpumask_var(policy->cpus);
@@ -1019,6 +973,22 @@ module_out:
 	return ret;
 }
 
+static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
+{
+	int j;
+
+	policy->last_cpu = policy->cpu;
+	policy->cpu = cpu;
+
+	for_each_cpu(j, policy->cpus)
+		per_cpu(cpufreq_policy_cpu, j) = cpu;
+
+#ifdef CONFIG_CPU_FREQ_TABLE
+	cpufreq_frequency_table_update_policy_cpu(policy);
+#endif
+	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+			CPUFREQ_UPDATE_POLICY_CPU, policy);
+}
 
 /**
  * __cpufreq_remove_dev - remove a CPU device
@@ -1029,129 +999,103 @@ module_out:
  */
 static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
-	unsigned int cpu = dev->id;
+	unsigned int cpu = dev->id, ret, cpus;
 	unsigned long flags;
 	struct cpufreq_policy *data;
 	struct kobject *kobj;
 	struct completion *cmp;
-#ifdef CONFIG_SMP
 	struct device *cpu_dev;
-	unsigned int j;
-#endif
 
-	pr_debug("unregistering CPU %u\n", cpu);
+	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
 
 	spin_lock_irqsave(&cpufreq_driver_lock, flags);
+
 	data = per_cpu(cpufreq_cpu_data, cpu);
+	per_cpu(cpufreq_cpu_data, cpu) = NULL;
+
+	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
 	if (!data) {
-		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-		unlock_policy_rwsem_write(cpu);
+		pr_debug("%s: No cpu_data found\n", __func__);
 		return -EINVAL;
 	}
-	per_cpu(cpufreq_cpu_data, cpu) = NULL;
 
+	if (cpufreq_driver->target)
+		__cpufreq_governor(data, CPUFREQ_GOV_STOP);
 
-#ifdef CONFIG_SMP
-	/* if this isn't the CPU which is the parent of the kobj, we
-	 * only need to unlink, put and exit
-	 */
-	if (unlikely(cpu != data->cpu)) {
-		pr_debug("removing link\n");
-		cpumask_clear_cpu(cpu, data->cpus);
-		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-		kobj = &dev->kobj;
-		cpufreq_cpu_put(data);
-		unlock_policy_rwsem_write(cpu);
-		sysfs_remove_link(kobj, "cpufreq");
-		return 0;
-	}
+#ifdef CONFIG_HOTPLUG_CPU
+	if (!cpufreq_driver->setpolicy)
+		strncpy(per_cpu(cpufreq_cpu_governor, cpu),
+			data->governor->name, CPUFREQ_NAME_LEN);
 #endif
 
-#ifdef CONFIG_SMP
+	WARN_ON(lock_policy_rwsem_write(cpu));
+	cpus = cpumask_weight(data->cpus);
+	cpumask_clear_cpu(cpu, data->cpus);
+	unlock_policy_rwsem_write(cpu);
 
-#ifdef CONFIG_HOTPLUG_CPU
-	strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
-			CPUFREQ_NAME_LEN);
-#endif
+	if (cpu != data->cpu) {
+		sysfs_remove_link(&dev->kobj, "cpufreq");
+	} else if (cpus > 1) {
+		/* first sibling now owns the new sysfs dir */
+		cpu_dev = get_cpu_device(cpumask_first(data->cpus));
+		sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
+		ret = kobject_move(&data->kobj, &cpu_dev->kobj);
+		if (ret) {
+			pr_err("%s: Failed to move kobj: %d", __func__, ret);
 
-	/* if we have other CPUs still registered, we need to unlink them,
-	 * or else wait_for_completion below will lock up. Clean the
-	 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
-	 * the sysfs links afterwards.
-	 */
-	if (unlikely(cpumask_weight(data->cpus) > 1)) {
-		for_each_cpu(j, data->cpus) {
-			if (j == cpu)
-				continue;
-			per_cpu(cpufreq_cpu_data, j) = NULL;
-		}
-	}
+			WARN_ON(lock_policy_rwsem_write(cpu));
+			cpumask_set_cpu(cpu, data->cpus);
 
-	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
+			spin_lock_irqsave(&cpufreq_driver_lock, flags);
+			per_cpu(cpufreq_cpu_data, cpu) = data;
+			spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-	if (unlikely(cpumask_weight(data->cpus) > 1)) {
-		for_each_cpu(j, data->cpus) {
-			if (j == cpu)
-				continue;
-			pr_debug("removing link for cpu %u\n", j);
-#ifdef CONFIG_HOTPLUG_CPU
-			strncpy(per_cpu(cpufreq_cpu_governor, j),
-				data->governor->name, CPUFREQ_NAME_LEN);
-#endif
-			cpu_dev = get_cpu_device(j);
-			kobj = &cpu_dev->kobj;
 			unlock_policy_rwsem_write(cpu);
-			sysfs_remove_link(kobj, "cpufreq");
-			lock_policy_rwsem_write(cpu);
-			cpufreq_cpu_put(data);
-		}
-	}
-#else
-	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-#endif
 
-	if (cpufreq_driver->target)
-		__cpufreq_governor(data, CPUFREQ_GOV_STOP);
+			ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
+					"cpufreq");
+			return -EINVAL;
+		}
 
-	kobj = &data->kobj;
-	cmp = &data->kobj_unregister;
-	unlock_policy_rwsem_write(cpu);
-	kobject_put(kobj);
+		WARN_ON(lock_policy_rwsem_write(cpu));
+		update_policy_cpu(data, cpu_dev->id);
+		unlock_policy_rwsem_write(cpu);
+		pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
+				__func__, cpu_dev->id, cpu);
+	}
 
-	/* we need to make sure that the underlying kobj is actually
-	 * not referenced anymore by anybody before we proceed with
-	 * unloading.
-	 */
-	pr_debug("waiting for dropping of refcount\n");
-	wait_for_completion(cmp);
-	pr_debug("wait complete\n");
+	pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
+	cpufreq_cpu_put(data);
 
-	lock_policy_rwsem_write(cpu);
-	if (cpufreq_driver->exit)
-		cpufreq_driver->exit(data);
-	unlock_policy_rwsem_write(cpu);
+	/* If cpu is last user of policy, free policy */
+	if (cpus == 1) {
+		lock_policy_rwsem_read(cpu);
+		kobj = &data->kobj;
+		cmp = &data->kobj_unregister;
+		unlock_policy_rwsem_read(cpu);
+		kobject_put(kobj);
+
+		/* we need to make sure that the underlying kobj is actually
+		 * not referenced anymore by anybody before we proceed with
+		 * unloading.
+		 */
+		pr_debug("waiting for dropping of refcount\n");
+		wait_for_completion(cmp);
+		pr_debug("wait complete\n");
 
-#ifdef CONFIG_HOTPLUG_CPU
-	/* when the CPU which is the parent of the kobj is hotplugged
-	 * offline, check for siblings, and create cpufreq sysfs interface
-	 * and symlinks
-	 */
-	if (unlikely(cpumask_weight(data->cpus) > 1)) {
-		/* first sibling now owns the new sysfs dir */
-		cpumask_clear_cpu(cpu, data->cpus);
-		cpufreq_add_dev(get_cpu_device(cpumask_first(data->cpus)), NULL);
+		if (cpufreq_driver->exit)
+			cpufreq_driver->exit(data);
 
-		/* finally remove our own symlink */
-		lock_policy_rwsem_write(cpu);
-		__cpufreq_remove_dev(dev, sif);
+		free_cpumask_var(data->related_cpus);
+		free_cpumask_var(data->cpus);
+		kfree(data);
+	} else if (cpufreq_driver->target) {
+		__cpufreq_governor(data, CPUFREQ_GOV_START);
+		__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
 	}
-#endif
-
-	free_cpumask_var(data->related_cpus);
-	free_cpumask_var(data->cpus);
-	kfree(data);
 
+	per_cpu(cpufreq_policy_cpu, cpu) = -1;
 	return 0;
 }
 
@@ -1164,9 +1108,6 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 	if (cpu_is_offline(cpu))
 		return 0;
 
-	if (unlikely(lock_policy_rwsem_write(cpu)))
-		BUG();
-
 	retval = __cpufreq_remove_dev(dev, sif);
 	return retval;
 }
@@ -1215,9 +1156,13 @@ static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
  */
 unsigned int cpufreq_quick_get(unsigned int cpu)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+	struct cpufreq_policy *policy;
 	unsigned int ret_freq = 0;
 
+	if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
+		return cpufreq_driver->get(cpu);
+
+	policy = cpufreq_cpu_get(cpu);
 	if (policy) {
 		ret_freq = policy->cur;
 		cpufreq_cpu_put(policy);
@@ -1385,6 +1330,20 @@ static struct syscore_ops cpufreq_syscore_ops = {
 	.resume		= cpufreq_bp_resume,
 };
 
+/**
+ *	cpufreq_get_current_driver - return current driver's name
+ *
+ *	Return the name string of the currently loaded cpufreq driver
+ *	or NULL, if none.
+ */
+const char *cpufreq_get_current_driver(void)
+{
+	if (cpufreq_driver)
+		return cpufreq_driver->name;
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
 
 /*********************************************************************
  *                     NOTIFIER LISTS INTERFACE                      *
@@ -1407,6 +1366,9 @@ int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
 {
 	int ret;
 
+	if (cpufreq_disabled())
+		return -EINVAL;
+
 	WARN_ON(!init_cpufreq_transition_notifier_list_called);
 
 	switch (list) {
@@ -1441,6 +1403,9 @@ int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
 {
 	int ret;
 
+	if (cpufreq_disabled())
+		return -EINVAL;
+
 	switch (list) {
 	case CPUFREQ_TRANSITION_NOTIFIER:
 		ret = srcu_notifier_chain_unregister(
@@ -1486,7 +1451,7 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
 	if (target_freq == policy->cur)
 		return 0;
 
-	if (cpu_online(policy->cpu) && cpufreq_driver->target)
+	if (cpufreq_driver->target)
 		retval = cpufreq_driver->target(policy, target_freq, relation);
 
 	return retval;
@@ -1521,7 +1486,10 @@ int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
 {
 	int ret = 0;
 
-	if (!(cpu_online(cpu) && cpufreq_driver->getavg))
+	if (cpufreq_disabled())
+		return ret;
+
+	if (!cpufreq_driver->getavg)
 		return 0;
 
 	policy = cpufreq_cpu_get(policy->cpu);
@@ -1576,6 +1544,11 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 						policy->cpu, event);
 	ret = policy->governor->governor(policy, event);
 
+	if (event == CPUFREQ_GOV_START)
+		policy->governor->initialized++;
+	else if (event == CPUFREQ_GOV_STOP)
+		policy->governor->initialized--;
+
 	/* we keep one module reference alive for
 			each CPU governed by this CPU */
 	if ((event != CPUFREQ_GOV_START) || ret)
@@ -1599,6 +1572,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)
 
 	mutex_lock(&cpufreq_governor_mutex);
 
+	governor->initialized = 0;
 	err = -EBUSY;
 	if (__find_governor(governor->name) == NULL) {
 		err = 0;
@@ -1796,7 +1770,7 @@ int cpufreq_update_policy(unsigned int cpu)
 			pr_debug("Driver did not initialize current freq");
 			data->cur = policy.cur;
 		} else {
-			if (data->cur != policy.cur)
+			if (data->cur != policy.cur && cpufreq_driver->target)
 				cpufreq_out_of_sync(cpu, data->cur,
 								policy.cur);
 		}
@@ -1828,9 +1802,6 @@ static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
 			break;
 		case CPU_DOWN_PREPARE:
 		case CPU_DOWN_PREPARE_FROZEN:
-			if (unlikely(lock_policy_rwsem_write(cpu)))
-				BUG();
-
 			__cpufreq_remove_dev(dev, NULL);
 			break;
 		case CPU_DOWN_FAILED:
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index 64ef737e7e72..4fd0006b1291 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -25,7 +25,7 @@
 
 #include "cpufreq_governor.h"
 
-/* Conservative governor macors */
+/* Conservative governor macros */
 #define DEF_FREQUENCY_UP_THRESHOLD		(80)
 #define DEF_FREQUENCY_DOWN_THRESHOLD		(20)
 #define DEF_SAMPLING_DOWN_FACTOR		(1)
@@ -113,17 +113,20 @@ static void cs_check_cpu(int cpu, unsigned int load)
 
 static void cs_dbs_timer(struct work_struct *work)
 {
+	struct delayed_work *dw = to_delayed_work(work);
 	struct cs_cpu_dbs_info_s *dbs_info = container_of(work,
 			struct cs_cpu_dbs_info_s, cdbs.work.work);
-	unsigned int cpu = dbs_info->cdbs.cpu;
+	unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
+	struct cs_cpu_dbs_info_s *core_dbs_info = &per_cpu(cs_cpu_dbs_info,
+			cpu);
 	int delay = delay_for_sampling_rate(cs_tuners.sampling_rate);
 
-	mutex_lock(&dbs_info->cdbs.timer_mutex);
+	mutex_lock(&core_dbs_info->cdbs.timer_mutex);
+	if (need_load_eval(&core_dbs_info->cdbs, cs_tuners.sampling_rate))
+		dbs_check_cpu(&cs_dbs_data, cpu);
 
-	dbs_check_cpu(&cs_dbs_data, cpu);
-
-	schedule_delayed_work_on(cpu, &dbs_info->cdbs.work, delay);
-	mutex_unlock(&dbs_info->cdbs.timer_mutex);
+	schedule_delayed_work_on(smp_processor_id(), dw, delay);
+	mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
 }
 
 static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
@@ -141,7 +144,7 @@ static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 
 	/*
 	 * we only care if our internally tracked freq moves outside the 'valid'
-	 * ranges of freqency available to us otherwise we do not change it
+	 * ranges of frequency available to us otherwise we do not change it
 	*/
 	if (dbs_info->requested_freq > policy->max
 			|| dbs_info->requested_freq < policy->min)
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 6c5f1d383cdc..5a76086ff09b 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -161,25 +161,48 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 }
 EXPORT_SYMBOL_GPL(dbs_check_cpu);
 
-static inline void dbs_timer_init(struct dbs_data *dbs_data,
-		struct cpu_dbs_common_info *cdbs, unsigned int sampling_rate)
+static inline void dbs_timer_init(struct dbs_data *dbs_data, int cpu,
+				  unsigned int sampling_rate)
 {
 	int delay = delay_for_sampling_rate(sampling_rate);
+	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
 
-	INIT_DEFERRABLE_WORK(&cdbs->work, dbs_data->gov_dbs_timer);
-	schedule_delayed_work_on(cdbs->cpu, &cdbs->work, delay);
+	schedule_delayed_work_on(cpu, &cdbs->work, delay);
 }
 
-static inline void dbs_timer_exit(struct cpu_dbs_common_info *cdbs)
+static inline void dbs_timer_exit(struct dbs_data *dbs_data, int cpu)
 {
+	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
+
 	cancel_delayed_work_sync(&cdbs->work);
 }
 
+/* Will return if we need to evaluate cpu load again or not */
+bool need_load_eval(struct cpu_dbs_common_info *cdbs,
+		unsigned int sampling_rate)
+{
+	if (policy_is_shared(cdbs->cur_policy)) {
+		ktime_t time_now = ktime_get();
+		s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
+
+		/* Do nothing if we recently have sampled */
+		if (delta_us < (s64)(sampling_rate / 2))
+			return false;
+		else
+			cdbs->time_stamp = time_now;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(need_load_eval);
+
 int cpufreq_governor_dbs(struct dbs_data *dbs_data,
 		struct cpufreq_policy *policy, unsigned int event)
 {
 	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
 	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
+	struct cs_ops *cs_ops = NULL;
+	struct od_ops *od_ops = NULL;
 	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 	struct cpu_dbs_common_info *cpu_cdbs;
@@ -192,109 +215,111 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data,
 		cs_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
 		sampling_rate = &cs_tuners->sampling_rate;
 		ignore_nice = cs_tuners->ignore_nice;
+		cs_ops = dbs_data->gov_ops;
 	} else {
 		od_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
 		sampling_rate = &od_tuners->sampling_rate;
 		ignore_nice = od_tuners->ignore_nice;
+		od_ops = dbs_data->gov_ops;
 	}
 
 	switch (event) {
 	case CPUFREQ_GOV_START:
-		if ((!cpu_online(cpu)) || (!policy->cur))
+		if (!policy->cur)
 			return -EINVAL;
 
 		mutex_lock(&dbs_data->mutex);
 
-		dbs_data->enable++;
-		cpu_cdbs->cpu = cpu;
 		for_each_cpu(j, policy->cpus) {
-			struct cpu_dbs_common_info *j_cdbs;
-			j_cdbs = dbs_data->get_cpu_cdbs(j);
+			struct cpu_dbs_common_info *j_cdbs =
+				dbs_data->get_cpu_cdbs(j);
 
+			j_cdbs->cpu = j;
 			j_cdbs->cur_policy = policy;
 			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
 					&j_cdbs->prev_cpu_wall);
 			if (ignore_nice)
 				j_cdbs->prev_cpu_nice =
 					kcpustat_cpu(j).cpustat[CPUTIME_NICE];
-		}
 
-		/*
-		 * Start the timerschedule work, when this governor is used for
-		 * first time
-		 */
-		if (dbs_data->enable != 1)
-			goto second_time;
-
-		rc = sysfs_create_group(cpufreq_global_kobject,
-				dbs_data->attr_group);
-		if (rc) {
-			mutex_unlock(&dbs_data->mutex);
-			return rc;
+			mutex_init(&j_cdbs->timer_mutex);
+			INIT_DEFERRABLE_WORK(&j_cdbs->work,
+					     dbs_data->gov_dbs_timer);
 		}
 
-		/* policy latency is in nS. Convert it to uS first */
-		latency = policy->cpuinfo.transition_latency / 1000;
-		if (latency == 0)
-			latency = 1;
+		if (!policy->governor->initialized) {
+			rc = sysfs_create_group(cpufreq_global_kobject,
+					dbs_data->attr_group);
+			if (rc) {
+				mutex_unlock(&dbs_data->mutex);
+				return rc;
+			}
+		}
 
 		/*
 		 * conservative does not implement micro like ondemand
 		 * governor, thus we are bound to jiffes/HZ
 		 */
 		if (dbs_data->governor == GOV_CONSERVATIVE) {
-			struct cs_ops *ops = dbs_data->gov_ops;
+			cs_dbs_info->down_skip = 0;
+			cs_dbs_info->enable = 1;
+			cs_dbs_info->requested_freq = policy->cur;
 
-			cpufreq_register_notifier(ops->notifier_block,
-					CPUFREQ_TRANSITION_NOTIFIER);
+			if (!policy->governor->initialized) {
+				cpufreq_register_notifier(cs_ops->notifier_block,
+						CPUFREQ_TRANSITION_NOTIFIER);
 
-			dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
-				jiffies_to_usecs(10);
+				dbs_data->min_sampling_rate =
+					MIN_SAMPLING_RATE_RATIO *
+					jiffies_to_usecs(10);
+			}
 		} else {
-			struct od_ops *ops = dbs_data->gov_ops;
+			od_dbs_info->rate_mult = 1;
+			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
+			od_ops->powersave_bias_init_cpu(cpu);
 
-			od_tuners->io_is_busy = ops->io_busy();
+			if (!policy->governor->initialized)
+				od_tuners->io_is_busy = od_ops->io_busy();
 		}
 
+		if (policy->governor->initialized)
+			goto unlock;
+
+		/* policy latency is in nS. Convert it to uS first */
+		latency = policy->cpuinfo.transition_latency / 1000;
+		if (latency == 0)
+			latency = 1;
+
 		/* Bring kernel and HW constraints together */
 		dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
 				MIN_LATENCY_MULTIPLIER * latency);
 		*sampling_rate = max(dbs_data->min_sampling_rate, latency *
 				LATENCY_MULTIPLIER);
-
-second_time:
-		if (dbs_data->governor == GOV_CONSERVATIVE) {
-			cs_dbs_info->down_skip = 0;
-			cs_dbs_info->enable = 1;
-			cs_dbs_info->requested_freq = policy->cur;
-		} else {
-			struct od_ops *ops = dbs_data->gov_ops;
-			od_dbs_info->rate_mult = 1;
-			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
-			ops->powersave_bias_init_cpu(cpu);
-		}
+unlock:
 		mutex_unlock(&dbs_data->mutex);
 
-		mutex_init(&cpu_cdbs->timer_mutex);
-		dbs_timer_init(dbs_data, cpu_cdbs, *sampling_rate);
+		/* Initiate timer time stamp */
+		cpu_cdbs->time_stamp = ktime_get();
+
+		for_each_cpu(j, policy->cpus)
+			dbs_timer_init(dbs_data, j, *sampling_rate);
 		break;
 
 	case CPUFREQ_GOV_STOP:
 		if (dbs_data->governor == GOV_CONSERVATIVE)
 			cs_dbs_info->enable = 0;
 
-		dbs_timer_exit(cpu_cdbs);
+		for_each_cpu(j, policy->cpus)
+			dbs_timer_exit(dbs_data, j);
 
 		mutex_lock(&dbs_data->mutex);
 		mutex_destroy(&cpu_cdbs->timer_mutex);
-		dbs_data->enable--;
-		if (!dbs_data->enable) {
-			struct cs_ops *ops = dbs_data->gov_ops;
 
+		if (policy->governor->initialized == 1) {
 			sysfs_remove_group(cpufreq_global_kobject,
 					dbs_data->attr_group);
 			if (dbs_data->governor == GOV_CONSERVATIVE)
-				cpufreq_unregister_notifier(ops->notifier_block,
+				cpufreq_unregister_notifier(cs_ops->notifier_block,
 						CPUFREQ_TRANSITION_NOTIFIER);
 		}
 		mutex_unlock(&dbs_data->mutex);
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index f6616540c53d..d2ac91150600 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -82,6 +82,7 @@ struct cpu_dbs_common_info {
 	 * the governor or limits.
 	 */
 	struct mutex timer_mutex;
+	ktime_t time_stamp;
 };
 
 struct od_cpu_dbs_info_s {
@@ -108,7 +109,7 @@ struct od_dbs_tuners {
 	unsigned int sampling_rate;
 	unsigned int sampling_down_factor;
 	unsigned int up_threshold;
-	unsigned int down_differential;
+	unsigned int adj_up_threshold;
 	unsigned int powersave_bias;
 	unsigned int io_is_busy;
 };
@@ -129,7 +130,6 @@ struct dbs_data {
 	#define GOV_CONSERVATIVE	1
 	int governor;
 	unsigned int min_sampling_rate;
-	unsigned int enable; /* number of CPUs using this policy */
 	struct attribute_group *attr_group;
 	void *tuners;
 
@@ -171,6 +171,8 @@ static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 
 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall);
 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
+bool need_load_eval(struct cpu_dbs_common_info *cdbs,
+		unsigned int sampling_rate);
 int cpufreq_governor_dbs(struct dbs_data *dbs_data,
 		struct cpufreq_policy *policy, unsigned int event);
 #endif /* _CPUFREQ_GOVERNER_H */
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 7731f7c7e79a..f3eb26cd848f 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -26,7 +26,7 @@
 
 #include "cpufreq_governor.h"
 
-/* On-demand governor macors */
+/* On-demand governor macros */
 #define DEF_FREQUENCY_DOWN_DIFFERENTIAL		(10)
 #define DEF_FREQUENCY_UP_THRESHOLD		(80)
 #define DEF_SAMPLING_DOWN_FACTOR		(1)
@@ -47,7 +47,8 @@ static struct cpufreq_governor cpufreq_gov_ondemand;
 static struct od_dbs_tuners od_tuners = {
 	.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
 	.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
-	.down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
+	.adj_up_threshold = DEF_FREQUENCY_UP_THRESHOLD -
+			    DEF_FREQUENCY_DOWN_DIFFERENTIAL,
 	.ignore_nice = 0,
 	.powersave_bias = 0,
 };
@@ -65,7 +66,7 @@ static void ondemand_powersave_bias_init_cpu(int cpu)
  * efficient idling at a higher frequency/voltage is.
  * Pavel Machek says this is not so for various generations of AMD and old
  * Intel systems.
- * Mike Chan (androidlcom) calis this is also not true for ARM.
+ * Mike Chan (android.com) claims this is also not true for ARM.
  * Because of this, whitelist specific known (series) of CPUs by default, and
  * leave all others up to the user.
  */
@@ -73,7 +74,7 @@ static int should_io_be_busy(void)
 {
 #if defined(CONFIG_X86)
 	/*
-	 * For Intel, Core 2 (model 15) andl later have an efficient idle.
+	 * For Intel, Core 2 (model 15) and later have an efficient idle.
 	 */
 	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
 			boot_cpu_data.x86 == 6 &&
@@ -158,8 +159,8 @@ static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq)
 
 /*
  * Every sampling_rate, we check, if current idle time is less than 20%
- * (default), then we try to increase frequency Every sampling_rate, we look for
- * a the lowest frequency which can sustain the load while keeping idle time
+ * (default), then we try to increase frequency. Every sampling_rate, we look
+ * for the lowest frequency which can sustain the load while keeping idle time
  * over 30%. If such a frequency exist, we try to decrease to this frequency.
  *
  * Any frequency increase takes it to the maximum frequency. Frequency reduction
@@ -192,11 +193,9 @@ static void od_check_cpu(int cpu, unsigned int load_freq)
 	 * support the current CPU usage without triggering the up policy. To be
 	 * safe, we focus 10 points under the threshold.
 	 */
-	if (load_freq < (od_tuners.up_threshold - od_tuners.down_differential) *
-			policy->cur) {
+	if (load_freq < od_tuners.adj_up_threshold * policy->cur) {
 		unsigned int freq_next;
-		freq_next = load_freq / (od_tuners.up_threshold -
-				od_tuners.down_differential);
+		freq_next = load_freq / od_tuners.adj_up_threshold;
 
 		/* No longer fully busy, reset rate_mult */
 		dbs_info->rate_mult = 1;
@@ -218,33 +217,42 @@ static void od_check_cpu(int cpu, unsigned int load_freq)
 
 static void od_dbs_timer(struct work_struct *work)
 {
+	struct delayed_work *dw = to_delayed_work(work);
 	struct od_cpu_dbs_info_s *dbs_info =
 		container_of(work, struct od_cpu_dbs_info_s, cdbs.work.work);
-	unsigned int cpu = dbs_info->cdbs.cpu;
-	int delay, sample_type = dbs_info->sample_type;
+	unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
+	struct od_cpu_dbs_info_s *core_dbs_info = &per_cpu(od_cpu_dbs_info,
+			cpu);
+	int delay, sample_type = core_dbs_info->sample_type;
+	bool eval_load;
 
-	mutex_lock(&dbs_info->cdbs.timer_mutex);
+	mutex_lock(&core_dbs_info->cdbs.timer_mutex);
+	eval_load = need_load_eval(&core_dbs_info->cdbs,
+			od_tuners.sampling_rate);
 
 	/* Common NORMAL_SAMPLE setup */
-	dbs_info->sample_type = OD_NORMAL_SAMPLE;
+	core_dbs_info->sample_type = OD_NORMAL_SAMPLE;
 	if (sample_type == OD_SUB_SAMPLE) {
-		delay = dbs_info->freq_lo_jiffies;
-		__cpufreq_driver_target(dbs_info->cdbs.cur_policy,
-			dbs_info->freq_lo, CPUFREQ_RELATION_H);
+		delay = core_dbs_info->freq_lo_jiffies;
+		if (eval_load)
+			__cpufreq_driver_target(core_dbs_info->cdbs.cur_policy,
+						core_dbs_info->freq_lo,
+						CPUFREQ_RELATION_H);
 	} else {
-		dbs_check_cpu(&od_dbs_data, cpu);
-		if (dbs_info->freq_lo) {
+		if (eval_load)
+			dbs_check_cpu(&od_dbs_data, cpu);
+		if (core_dbs_info->freq_lo) {
 			/* Setup timer for SUB_SAMPLE */
-			dbs_info->sample_type = OD_SUB_SAMPLE;
-			delay = dbs_info->freq_hi_jiffies;
+			core_dbs_info->sample_type = OD_SUB_SAMPLE;
+			delay = core_dbs_info->freq_hi_jiffies;
 		} else {
 			delay = delay_for_sampling_rate(od_tuners.sampling_rate
-						* dbs_info->rate_mult);
+						* core_dbs_info->rate_mult);
 		}
 	}
 
-	schedule_delayed_work_on(cpu, &dbs_info->cdbs.work, delay);
-	mutex_unlock(&dbs_info->cdbs.timer_mutex);
+	schedule_delayed_work_on(smp_processor_id(), dw, delay);
+	mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
 }
 
 /************************** sysfs interface ************************/
@@ -259,7 +267,7 @@ static ssize_t show_sampling_rate_min(struct kobject *kobj,
  * update_sampling_rate - update sampling rate effective immediately if needed.
  * @new_rate: new sampling rate
  *
- * If new rate is smaller than the old, simply updaing
+ * If new rate is smaller than the old, simply updating
  * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the
  * original sampling_rate was 1 second and the requested new sampling rate is 10
  * ms because the user needs immediate reaction from ondemand governor, but not
@@ -287,7 +295,7 @@ static void update_sampling_rate(unsigned int new_rate)
 			cpufreq_cpu_put(policy);
 			continue;
 		}
-		dbs_info = &per_cpu(od_cpu_dbs_info, policy->cpu);
+		dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
 		cpufreq_cpu_put(policy);
 
 		mutex_lock(&dbs_info->cdbs.timer_mutex);
@@ -306,8 +314,7 @@ static void update_sampling_rate(unsigned int new_rate)
 			cancel_delayed_work_sync(&dbs_info->cdbs.work);
 			mutex_lock(&dbs_info->cdbs.timer_mutex);
 
-			schedule_delayed_work_on(dbs_info->cdbs.cpu,
-					&dbs_info->cdbs.work,
+			schedule_delayed_work_on(cpu, &dbs_info->cdbs.work,
 					usecs_to_jiffies(new_rate));
 
 		}
@@ -351,6 +358,10 @@ static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
 			input < MIN_FREQUENCY_UP_THRESHOLD) {
 		return -EINVAL;
 	}
+	/* Calculate the new adj_up_threshold */
+	od_tuners.adj_up_threshold += input;
+	od_tuners.adj_up_threshold -= od_tuners.up_threshold;
+
 	od_tuners.up_threshold = input;
 	return count;
 }
@@ -507,7 +518,8 @@ static int __init cpufreq_gov_dbs_init(void)
 	if (idle_time != -1ULL) {
 		/* Idle micro accounting is supported. Use finer thresholds */
 		od_tuners.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
-		od_tuners.down_differential = MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
+		od_tuners.adj_up_threshold = MICRO_FREQUENCY_UP_THRESHOLD -
+					     MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
 		/*
 		 * In nohz/micro accounting case we set the minimum frequency
 		 * not depending on HZ, but fixed (very low). The deferred
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 9d7732b81044..2fd779eb1ed1 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -24,12 +24,6 @@
 
 static spinlock_t cpufreq_stats_lock;
 
-#define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
-static struct freq_attr _attr_##_name = {\
-	.attr = {.name = __stringify(_name), .mode = _mode, }, \
-	.show = _show,\
-};
-
 struct cpufreq_stats {
 	unsigned int cpu;
 	unsigned int total_trans;
@@ -136,17 +130,17 @@ static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 		return PAGE_SIZE;
 	return len;
 }
-CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
+cpufreq_freq_attr_ro(trans_table);
 #endif
 
-CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
-CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
+cpufreq_freq_attr_ro(total_trans);
+cpufreq_freq_attr_ro(time_in_state);
 
 static struct attribute *default_attrs[] = {
-	&_attr_total_trans.attr,
-	&_attr_time_in_state.attr,
+	&total_trans.attr,
+	&time_in_state.attr,
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
-	&_attr_trans_table.attr,
+	&trans_table.attr,
 #endif
 	NULL
 };
@@ -170,11 +164,13 @@ static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 static void cpufreq_stats_free_table(unsigned int cpu)
 {
 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
+
 	if (stat) {
+		pr_debug("%s: Free stat table\n", __func__);
 		kfree(stat->time_in_state);
 		kfree(stat);
+		per_cpu(cpufreq_stats_table, cpu) = NULL;
 	}
-	per_cpu(cpufreq_stats_table, cpu) = NULL;
 }
 
 /* must be called early in the CPU removal sequence (before
@@ -183,8 +179,14 @@ static void cpufreq_stats_free_table(unsigned int cpu)
 static void cpufreq_stats_free_sysfs(unsigned int cpu)
 {
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-	if (policy && policy->cpu == cpu)
+
+	if (!cpufreq_frequency_get_table(cpu))
+		return;
+
+	if (policy && !policy_is_shared(policy)) {
+		pr_debug("%s: Free sysfs stat\n", __func__);
 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
+	}
 	if (policy)
 		cpufreq_cpu_put(policy);
 }
@@ -262,6 +264,19 @@ error_get_fail:
 	return ret;
 }
 
+static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
+{
+	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
+			policy->last_cpu);
+
+	pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
+			policy->cpu, policy->last_cpu);
+	per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
+			policy->last_cpu);
+	per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
+	stat->cpu = policy->cpu;
+}
+
 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 		unsigned long val, void *data)
 {
@@ -269,6 +284,12 @@ static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 	struct cpufreq_policy *policy = data;
 	struct cpufreq_frequency_table *table;
 	unsigned int cpu = policy->cpu;
+
+	if (val == CPUFREQ_UPDATE_POLICY_CPU) {
+		cpufreq_stats_update_policy_cpu(policy);
+		return 0;
+	}
+
 	if (val != CPUFREQ_NOTIFY)
 		return 0;
 	table = cpufreq_frequency_get_table(cpu);
diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c
index c8c3d293cc57..bbeb9c0720a6 100644
--- a/drivers/cpufreq/cpufreq_userspace.c
+++ b/drivers/cpufreq/cpufreq_userspace.c
@@ -118,8 +118,6 @@ static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
 
 	switch (event) {
 	case CPUFREQ_GOV_START:
-		if (!cpu_online(cpu))
-			return -EINVAL;
 		BUG_ON(!policy->cur);
 		mutex_lock(&userspace_mutex);
 
diff --git a/drivers/cpufreq/db8500-cpufreq.c b/drivers/cpufreq/db8500-cpufreq.c
index 4f154bc0ebe4..79a84860ea56 100644
--- a/drivers/cpufreq/db8500-cpufreq.c
+++ b/drivers/cpufreq/db8500-cpufreq.c
@@ -128,9 +128,7 @@ static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
 	policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
 
 	/* policy sharing between dual CPUs */
-	cpumask_copy(policy->cpus, cpu_present_mask);
-
-	policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
+	cpumask_setall(policy->cpus);
 
 	return 0;
 }
diff --git a/drivers/cpufreq/exynos-cpufreq.c b/drivers/cpufreq/exynos-cpufreq.c
index 7012ea8bf1e7..81eb84a24fa7 100644
--- a/drivers/cpufreq/exynos-cpufreq.c
+++ b/drivers/cpufreq/exynos-cpufreq.c
@@ -227,19 +227,7 @@ static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	/* set the transition latency value */
 	policy->cpuinfo.transition_latency = 100000;
 
-	/*
-	 * EXYNOS4 multi-core processors has 2 cores
-	 * that the frequency cannot be set independently.
-	 * Each cpu is bound to the same speed.
-	 * So the affected cpu is all of the cpus.
-	 */
-	if (num_online_cpus() == 1) {
-		cpumask_copy(policy->related_cpus, cpu_possible_mask);
-		cpumask_copy(policy->cpus, cpu_online_mask);
-	} else {
-		policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
-		cpumask_setall(policy->cpus);
-	}
+	cpumask_setall(policy->cpus);
 
 	return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
 }
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 49cda256efb2..d7a79662e24c 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -63,9 +63,6 @@ int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 	pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
 					policy->min, policy->max, policy->cpu);
 
-	if (!cpu_online(policy->cpu))
-		return -EINVAL;
-
 	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 				     policy->cpuinfo.max_freq);
 
@@ -121,9 +118,6 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 		break;
 	}
 
-	if (!cpu_online(policy->cpu))
-		return -EINVAL;
-
 	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 		unsigned int freq = table[i].frequency;
 		if (freq == CPUFREQ_ENTRY_INVALID)
@@ -227,6 +221,15 @@ void cpufreq_frequency_table_put_attr(unsigned int cpu)
 }
 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 
+void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy)
+{
+	pr_debug("Updating show_table for new_cpu %u from last_cpu %u\n",
+			policy->cpu, policy->last_cpu);
+	per_cpu(cpufreq_show_table, policy->cpu) = per_cpu(cpufreq_show_table,
+			policy->last_cpu);
+	per_cpu(cpufreq_show_table, policy->last_cpu) = NULL;
+}
+
 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 {
 	return per_cpu(cpufreq_show_table, cpu);
diff --git a/drivers/cpufreq/highbank-cpufreq.c b/drivers/cpufreq/highbank-cpufreq.c
new file mode 100644
index 000000000000..66e3a71b81a3
--- /dev/null
+++ b/drivers/cpufreq/highbank-cpufreq.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2012 Calxeda, Inc.
+ *
+ * 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 driver provides the clk notifier callbacks that are used when
+ * the cpufreq-cpu0 driver changes to frequency to alert the highbank
+ * EnergyCore Management Engine (ECME) about the need to change
+ * voltage. The ECME interfaces with the actual voltage regulators.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/mailbox.h>
+#include <linux/platform_device.h>
+
+#define HB_CPUFREQ_CHANGE_NOTE	0x80000001
+#define HB_CPUFREQ_IPC_LEN	7
+#define HB_CPUFREQ_VOLT_RETRIES	15
+
+static int hb_voltage_change(unsigned int freq)
+{
+	int i;
+	u32 msg[HB_CPUFREQ_IPC_LEN];
+
+	msg[0] = HB_CPUFREQ_CHANGE_NOTE;
+	msg[1] = freq / 1000000;
+	for (i = 2; i < HB_CPUFREQ_IPC_LEN; i++)
+		msg[i] = 0;
+
+	return pl320_ipc_transmit(msg);
+}
+
+static int hb_cpufreq_clk_notify(struct notifier_block *nb,
+				unsigned long action, void *hclk)
+{
+	struct clk_notifier_data *clk_data = hclk;
+	int i = 0;
+
+	if (action == PRE_RATE_CHANGE) {
+		if (clk_data->new_rate > clk_data->old_rate)
+			while (hb_voltage_change(clk_data->new_rate))
+				if (i++ > HB_CPUFREQ_VOLT_RETRIES)
+					return NOTIFY_BAD;
+	} else if (action == POST_RATE_CHANGE) {
+		if (clk_data->new_rate < clk_data->old_rate)
+			while (hb_voltage_change(clk_data->new_rate))
+				if (i++ > HB_CPUFREQ_VOLT_RETRIES)
+					return NOTIFY_BAD;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block hb_cpufreq_clk_nb = {
+	.notifier_call = hb_cpufreq_clk_notify,
+};
+
+static int hb_cpufreq_driver_init(void)
+{
+	struct platform_device_info devinfo = { .name = "cpufreq-cpu0", };
+	struct device *cpu_dev;
+	struct clk *cpu_clk;
+	struct device_node *np;
+	int ret;
+
+	if (!of_machine_is_compatible("calxeda,highbank"))
+		return -ENODEV;
+
+	for_each_child_of_node(of_find_node_by_path("/cpus"), np)
+		if (of_get_property(np, "operating-points", NULL))
+			break;
+
+	if (!np) {
+		pr_err("failed to find highbank cpufreq node\n");
+		return -ENOENT;
+	}
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev) {
+		pr_err("failed to get highbank cpufreq device\n");
+		ret = -ENODEV;
+		goto out_put_node;
+	}
+
+	cpu_dev->of_node = np;
+
+	cpu_clk = clk_get(cpu_dev, NULL);
+	if (IS_ERR(cpu_clk)) {
+		ret = PTR_ERR(cpu_clk);
+		pr_err("failed to get cpu0 clock: %d\n", ret);
+		goto out_put_node;
+	}
+
+	ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
+	if (ret) {
+		pr_err("failed to register clk notifier: %d\n", ret);
+		goto out_put_node;
+	}
+
+	/* Instantiate cpufreq-cpu0 */
+	platform_device_register_full(&devinfo);
+
+out_put_node:
+	of_node_put(np);
+	return ret;
+}
+module_init(hb_cpufreq_driver_init);
+
+MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
+MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
new file mode 100644
index 000000000000..d6b6ef350cb6
--- /dev/null
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -0,0 +1,336 @@
+/*
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/opp.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define PU_SOC_VOLTAGE_NORMAL	1250000
+#define PU_SOC_VOLTAGE_HIGH	1275000
+#define FREQ_1P2_GHZ		1200000000
+
+static struct regulator *arm_reg;
+static struct regulator *pu_reg;
+static struct regulator *soc_reg;
+
+static struct clk *arm_clk;
+static struct clk *pll1_sys_clk;
+static struct clk *pll1_sw_clk;
+static struct clk *step_clk;
+static struct clk *pll2_pfd2_396m_clk;
+
+static struct device *cpu_dev;
+static struct cpufreq_frequency_table *freq_table;
+static unsigned int transition_latency;
+
+static int imx6q_verify_speed(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, freq_table);
+}
+
+static unsigned int imx6q_get_speed(unsigned int cpu)
+{
+	return clk_get_rate(arm_clk) / 1000;
+}
+
+static int imx6q_set_target(struct cpufreq_policy *policy,
+			    unsigned int target_freq, unsigned int relation)
+{
+	struct cpufreq_freqs freqs;
+	struct opp *opp;
+	unsigned long freq_hz, volt, volt_old;
+	unsigned int index, cpu;
+	int ret;
+
+	ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
+					     relation, &index);
+	if (ret) {
+		dev_err(cpu_dev, "failed to match target frequency %d: %d\n",
+			target_freq, ret);
+		return ret;
+	}
+
+	freqs.new = freq_table[index].frequency;
+	freq_hz = freqs.new * 1000;
+	freqs.old = clk_get_rate(arm_clk) / 1000;
+
+	if (freqs.old == freqs.new)
+		return 0;
+
+	for_each_online_cpu(cpu) {
+		freqs.cpu = cpu;
+		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+	}
+
+	rcu_read_lock();
+	opp = opp_find_freq_ceil(cpu_dev, &freq_hz);
+	if (IS_ERR(opp)) {
+		rcu_read_unlock();
+		dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
+		return PTR_ERR(opp);
+	}
+
+	volt = opp_get_voltage(opp);
+	rcu_read_unlock();
+	volt_old = regulator_get_voltage(arm_reg);
+
+	dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
+		freqs.old / 1000, volt_old / 1000,
+		freqs.new / 1000, volt / 1000);
+
+	/* scaling up?  scale voltage before frequency */
+	if (freqs.new > freqs.old) {
+		ret = regulator_set_voltage_tol(arm_reg, volt, 0);
+		if (ret) {
+			dev_err(cpu_dev,
+				"failed to scale vddarm up: %d\n", ret);
+			return ret;
+		}
+
+		/*
+		 * Need to increase vddpu and vddsoc for safety
+		 * if we are about to run at 1.2 GHz.
+		 */
+		if (freqs.new == FREQ_1P2_GHZ / 1000) {
+			regulator_set_voltage_tol(pu_reg,
+					PU_SOC_VOLTAGE_HIGH, 0);
+			regulator_set_voltage_tol(soc_reg,
+					PU_SOC_VOLTAGE_HIGH, 0);
+		}
+	}
+
+	/*
+	 * The setpoints are selected per PLL/PDF frequencies, so we need to
+	 * reprogram PLL for frequency scaling.  The procedure of reprogramming
+	 * PLL1 is as below.
+	 *
+	 *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
+	 *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
+	 *  - Disable pll2_pfd2_396m_clk
+	 */
+	clk_prepare_enable(pll2_pfd2_396m_clk);
+	clk_set_parent(step_clk, pll2_pfd2_396m_clk);
+	clk_set_parent(pll1_sw_clk, step_clk);
+	if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
+		clk_set_rate(pll1_sys_clk, freqs.new * 1000);
+		/*
+		 * If we are leaving 396 MHz set-point, we need to enable
+		 * pll1_sys_clk and disable pll2_pfd2_396m_clk to keep
+		 * their use count correct.
+		 */
+		if (freqs.old * 1000 <= clk_get_rate(pll2_pfd2_396m_clk)) {
+			clk_prepare_enable(pll1_sys_clk);
+			clk_disable_unprepare(pll2_pfd2_396m_clk);
+		}
+		clk_set_parent(pll1_sw_clk, pll1_sys_clk);
+		clk_disable_unprepare(pll2_pfd2_396m_clk);
+	} else {
+		/*
+		 * Disable pll1_sys_clk if pll2_pfd2_396m_clk is sufficient
+		 * to provide the frequency.
+		 */
+		clk_disable_unprepare(pll1_sys_clk);
+	}
+
+	/* Ensure the arm clock divider is what we expect */
+	ret = clk_set_rate(arm_clk, freqs.new * 1000);
+	if (ret) {
+		dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+		regulator_set_voltage_tol(arm_reg, volt_old, 0);
+		return ret;
+	}
+
+	/* scaling down?  scale voltage after frequency */
+	if (freqs.new < freqs.old) {
+		ret = regulator_set_voltage_tol(arm_reg, volt, 0);
+		if (ret)
+			dev_warn(cpu_dev,
+				 "failed to scale vddarm down: %d\n", ret);
+
+		if (freqs.old == FREQ_1P2_GHZ / 1000) {
+			regulator_set_voltage_tol(pu_reg,
+					PU_SOC_VOLTAGE_NORMAL, 0);
+			regulator_set_voltage_tol(soc_reg,
+					PU_SOC_VOLTAGE_NORMAL, 0);
+		}
+	}
+
+	for_each_online_cpu(cpu) {
+		freqs.cpu = cpu;
+		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+	}
+
+	return 0;
+}
+
+static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
+{
+	int ret;
+
+	ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
+	if (ret) {
+		dev_err(cpu_dev, "invalid frequency table: %d\n", ret);
+		return ret;
+	}
+
+	policy->cpuinfo.transition_latency = transition_latency;
+	policy->cur = clk_get_rate(arm_clk) / 1000;
+	cpumask_setall(policy->cpus);
+	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
+
+	return 0;
+}
+
+static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
+{
+	cpufreq_frequency_table_put_attr(policy->cpu);
+	return 0;
+}
+
+static struct freq_attr *imx6q_cpufreq_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+
+static struct cpufreq_driver imx6q_cpufreq_driver = {
+	.verify = imx6q_verify_speed,
+	.target = imx6q_set_target,
+	.get = imx6q_get_speed,
+	.init = imx6q_cpufreq_init,
+	.exit = imx6q_cpufreq_exit,
+	.name = "imx6q-cpufreq",
+	.attr = imx6q_cpufreq_attr,
+};
+
+static int imx6q_cpufreq_probe(struct platform_device *pdev)
+{
+	struct device_node *np;
+	struct opp *opp;
+	unsigned long min_volt, max_volt;
+	int num, ret;
+
+	cpu_dev = &pdev->dev;
+
+	np = of_find_node_by_path("/cpus/cpu@0");
+	if (!np) {
+		dev_err(cpu_dev, "failed to find cpu0 node\n");
+		return -ENOENT;
+	}
+
+	cpu_dev->of_node = np;
+
+	arm_clk = devm_clk_get(cpu_dev, "arm");
+	pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys");
+	pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw");
+	step_clk = devm_clk_get(cpu_dev, "step");
+	pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m");
+	if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
+	    IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
+		dev_err(cpu_dev, "failed to get clocks\n");
+		ret = -ENOENT;
+		goto put_node;
+	}
+
+	arm_reg = devm_regulator_get(cpu_dev, "arm");
+	pu_reg = devm_regulator_get(cpu_dev, "pu");
+	soc_reg = devm_regulator_get(cpu_dev, "soc");
+	if (!arm_reg || !pu_reg || !soc_reg) {
+		dev_err(cpu_dev, "failed to get regulators\n");
+		ret = -ENOENT;
+		goto put_node;
+	}
+
+	/* We expect an OPP table supplied by platform */
+	num = opp_get_opp_count(cpu_dev);
+	if (num < 0) {
+		ret = num;
+		dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
+		goto put_node;
+	}
+
+	ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
+	if (ret) {
+		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
+		goto put_node;
+	}
+
+	if (of_property_read_u32(np, "clock-latency", &transition_latency))
+		transition_latency = CPUFREQ_ETERNAL;
+
+	/*
+	 * OPP is maintained in order of increasing frequency, and
+	 * freq_table initialised from OPP is therefore sorted in the
+	 * same order.
+	 */
+	rcu_read_lock();
+	opp = opp_find_freq_exact(cpu_dev,
+				  freq_table[0].frequency * 1000, true);
+	min_volt = opp_get_voltage(opp);
+	opp = opp_find_freq_exact(cpu_dev,
+				  freq_table[--num].frequency * 1000, true);
+	max_volt = opp_get_voltage(opp);
+	rcu_read_unlock();
+	ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
+	if (ret > 0)
+		transition_latency += ret * 1000;
+
+	/* Count vddpu and vddsoc latency in for 1.2 GHz support */
+	if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) {
+		ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL,
+						 PU_SOC_VOLTAGE_HIGH);
+		if (ret > 0)
+			transition_latency += ret * 1000;
+		ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL,
+						 PU_SOC_VOLTAGE_HIGH);
+		if (ret > 0)
+			transition_latency += ret * 1000;
+	}
+
+	ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
+	if (ret) {
+		dev_err(cpu_dev, "failed register driver: %d\n", ret);
+		goto free_freq_table;
+	}
+
+	of_node_put(np);
+	return 0;
+
+free_freq_table:
+	opp_free_cpufreq_table(cpu_dev, &freq_table);
+put_node:
+	of_node_put(np);
+	return ret;
+}
+
+static int imx6q_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_driver(&imx6q_cpufreq_driver);
+	opp_free_cpufreq_table(cpu_dev, &freq_table);
+
+	return 0;
+}
+
+static struct platform_driver imx6q_cpufreq_platdrv = {
+	.driver = {
+		.name	= "imx6q-cpufreq",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= imx6q_cpufreq_probe,
+	.remove		= imx6q_cpufreq_remove,
+};
+module_platform_driver(imx6q_cpufreq_platdrv);
+
+MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
+MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
new file mode 100644
index 000000000000..e87996355da0
--- /dev/null
+++ b/drivers/cpufreq/intel_pstate.c
@@ -0,0 +1,807 @@
+/*
+ * cpufreq_snb.c: Native P state management for Intel processors
+ *
+ * (C) Copyright 2012 Intel Corporation
+ * Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/module.h>
+#include <linux/ktime.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <trace/events/power.h>
+
+#include <asm/div64.h>
+#include <asm/msr.h>
+#include <asm/cpu_device_id.h>
+
+#define SAMPLE_COUNT		3
+
+#define FRAC_BITS 8
+#define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
+#define fp_toint(X) ((X) >> FRAC_BITS)
+
+static inline int32_t mul_fp(int32_t x, int32_t y)
+{
+	return ((int64_t)x * (int64_t)y) >> FRAC_BITS;
+}
+
+static inline int32_t div_fp(int32_t x, int32_t y)
+{
+	return div_s64((int64_t)x << FRAC_BITS, (int64_t)y);
+}
+
+struct sample {
+	ktime_t start_time;
+	ktime_t end_time;
+	int core_pct_busy;
+	int pstate_pct_busy;
+	u64 duration_us;
+	u64 idletime_us;
+	u64 aperf;
+	u64 mperf;
+	int freq;
+};
+
+struct pstate_data {
+	int	current_pstate;
+	int	min_pstate;
+	int	max_pstate;
+	int	turbo_pstate;
+};
+
+struct _pid {
+	int setpoint;
+	int32_t integral;
+	int32_t p_gain;
+	int32_t i_gain;
+	int32_t d_gain;
+	int deadband;
+	int last_err;
+};
+
+struct cpudata {
+	int cpu;
+
+	char name[64];
+
+	struct timer_list timer;
+
+	struct pstate_adjust_policy *pstate_policy;
+	struct pstate_data pstate;
+	struct _pid pid;
+	struct _pid idle_pid;
+
+	int min_pstate_count;
+	int idle_mode;
+
+	ktime_t prev_sample;
+	u64	prev_idle_time_us;
+	u64	prev_aperf;
+	u64	prev_mperf;
+	int	sample_ptr;
+	struct sample samples[SAMPLE_COUNT];
+};
+
+static struct cpudata **all_cpu_data;
+struct pstate_adjust_policy {
+	int sample_rate_ms;
+	int deadband;
+	int setpoint;
+	int p_gain_pct;
+	int d_gain_pct;
+	int i_gain_pct;
+};
+
+static struct pstate_adjust_policy default_policy = {
+	.sample_rate_ms = 10,
+	.deadband = 0,
+	.setpoint = 109,
+	.p_gain_pct = 17,
+	.d_gain_pct = 0,
+	.i_gain_pct = 4,
+};
+
+struct perf_limits {
+	int no_turbo;
+	int max_perf_pct;
+	int min_perf_pct;
+	int32_t max_perf;
+	int32_t min_perf;
+};
+
+static struct perf_limits limits = {
+	.no_turbo = 0,
+	.max_perf_pct = 100,
+	.max_perf = int_tofp(1),
+	.min_perf_pct = 0,
+	.min_perf = 0,
+};
+
+static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
+			int deadband, int integral) {
+	pid->setpoint = setpoint;
+	pid->deadband  = deadband;
+	pid->integral  = int_tofp(integral);
+	pid->last_err  = setpoint - busy;
+}
+
+static inline void pid_p_gain_set(struct _pid *pid, int percent)
+{
+	pid->p_gain = div_fp(int_tofp(percent), int_tofp(100));
+}
+
+static inline void pid_i_gain_set(struct _pid *pid, int percent)
+{
+	pid->i_gain = div_fp(int_tofp(percent), int_tofp(100));
+}
+
+static inline void pid_d_gain_set(struct _pid *pid, int percent)
+{
+
+	pid->d_gain = div_fp(int_tofp(percent), int_tofp(100));
+}
+
+static signed int pid_calc(struct _pid *pid, int busy)
+{
+	signed int err, result;
+	int32_t pterm, dterm, fp_error;
+	int32_t integral_limit;
+
+	err = pid->setpoint - busy;
+	fp_error = int_tofp(err);
+
+	if (abs(err) <= pid->deadband)
+		return 0;
+
+	pterm = mul_fp(pid->p_gain, fp_error);
+
+	pid->integral += fp_error;
+
+	/* limit the integral term */
+	integral_limit = int_tofp(30);
+	if (pid->integral > integral_limit)
+		pid->integral = integral_limit;
+	if (pid->integral < -integral_limit)
+		pid->integral = -integral_limit;
+
+	dterm = mul_fp(pid->d_gain, (err - pid->last_err));
+	pid->last_err = err;
+
+	result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
+
+	return (signed int)fp_toint(result);
+}
+
+static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
+{
+	pid_p_gain_set(&cpu->pid, cpu->pstate_policy->p_gain_pct);
+	pid_d_gain_set(&cpu->pid, cpu->pstate_policy->d_gain_pct);
+	pid_i_gain_set(&cpu->pid, cpu->pstate_policy->i_gain_pct);
+
+	pid_reset(&cpu->pid,
+		cpu->pstate_policy->setpoint,
+		100,
+		cpu->pstate_policy->deadband,
+		0);
+}
+
+static inline void intel_pstate_idle_pid_reset(struct cpudata *cpu)
+{
+	pid_p_gain_set(&cpu->idle_pid, cpu->pstate_policy->p_gain_pct);
+	pid_d_gain_set(&cpu->idle_pid, cpu->pstate_policy->d_gain_pct);
+	pid_i_gain_set(&cpu->idle_pid, cpu->pstate_policy->i_gain_pct);
+
+	pid_reset(&cpu->idle_pid,
+		75,
+		50,
+		cpu->pstate_policy->deadband,
+		0);
+}
+
+static inline void intel_pstate_reset_all_pid(void)
+{
+	unsigned int cpu;
+	for_each_online_cpu(cpu) {
+		if (all_cpu_data[cpu])
+			intel_pstate_busy_pid_reset(all_cpu_data[cpu]);
+	}
+}
+
+/************************** debugfs begin ************************/
+static int pid_param_set(void *data, u64 val)
+{
+	*(u32 *)data = val;
+	intel_pstate_reset_all_pid();
+	return 0;
+}
+static int pid_param_get(void *data, u64 *val)
+{
+	*val = *(u32 *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get,
+			pid_param_set, "%llu\n");
+
+struct pid_param {
+	char *name;
+	void *value;
+};
+
+static struct pid_param pid_files[] = {
+	{"sample_rate_ms", &default_policy.sample_rate_ms},
+	{"d_gain_pct", &default_policy.d_gain_pct},
+	{"i_gain_pct", &default_policy.i_gain_pct},
+	{"deadband", &default_policy.deadband},
+	{"setpoint", &default_policy.setpoint},
+	{"p_gain_pct", &default_policy.p_gain_pct},
+	{NULL, NULL}
+};
+
+static struct dentry *debugfs_parent;
+static void intel_pstate_debug_expose_params(void)
+{
+	int i = 0;
+
+	debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
+	if (IS_ERR_OR_NULL(debugfs_parent))
+		return;
+	while (pid_files[i].name) {
+		debugfs_create_file(pid_files[i].name, 0660,
+				debugfs_parent, pid_files[i].value,
+				&fops_pid_param);
+		i++;
+	}
+}
+
+/************************** debugfs end ************************/
+
+/************************** sysfs begin ************************/
+#define show_one(file_name, object)					\
+	static ssize_t show_##file_name					\
+	(struct kobject *kobj, struct attribute *attr, char *buf)	\
+	{								\
+		return sprintf(buf, "%u\n", limits.object);		\
+	}
+
+static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
+				const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+	limits.no_turbo = clamp_t(int, input, 0 , 1);
+
+	return count;
+}
+
+static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b,
+				const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+
+	limits.max_perf_pct = clamp_t(int, input, 0 , 100);
+	limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
+	return count;
+}
+
+static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
+				const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+	limits.min_perf_pct = clamp_t(int, input, 0 , 100);
+	limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
+
+	return count;
+}
+
+show_one(no_turbo, no_turbo);
+show_one(max_perf_pct, max_perf_pct);
+show_one(min_perf_pct, min_perf_pct);
+
+define_one_global_rw(no_turbo);
+define_one_global_rw(max_perf_pct);
+define_one_global_rw(min_perf_pct);
+
+static struct attribute *intel_pstate_attributes[] = {
+	&no_turbo.attr,
+	&max_perf_pct.attr,
+	&min_perf_pct.attr,
+	NULL
+};
+
+static struct attribute_group intel_pstate_attr_group = {
+	.attrs = intel_pstate_attributes,
+};
+static struct kobject *intel_pstate_kobject;
+
+static void intel_pstate_sysfs_expose_params(void)
+{
+	int rc;
+
+	intel_pstate_kobject = kobject_create_and_add("intel_pstate",
+						&cpu_subsys.dev_root->kobj);
+	BUG_ON(!intel_pstate_kobject);
+	rc = sysfs_create_group(intel_pstate_kobject,
+				&intel_pstate_attr_group);
+	BUG_ON(rc);
+}
+
+/************************** sysfs end ************************/
+
+static int intel_pstate_min_pstate(void)
+{
+	u64 value;
+	rdmsrl(0xCE, value);
+	return (value >> 40) & 0xFF;
+}
+
+static int intel_pstate_max_pstate(void)
+{
+	u64 value;
+	rdmsrl(0xCE, value);
+	return (value >> 8) & 0xFF;
+}
+
+static int intel_pstate_turbo_pstate(void)
+{
+	u64 value;
+	int nont, ret;
+	rdmsrl(0x1AD, value);
+	nont = intel_pstate_max_pstate();
+	ret = ((value) & 255);
+	if (ret <= nont)
+		ret = nont;
+	return ret;
+}
+
+static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
+{
+	int max_perf = cpu->pstate.turbo_pstate;
+	int min_perf;
+	if (limits.no_turbo)
+		max_perf = cpu->pstate.max_pstate;
+
+	max_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.max_perf));
+	*max = clamp_t(int, max_perf,
+			cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
+
+	min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.min_perf));
+	*min = clamp_t(int, min_perf,
+			cpu->pstate.min_pstate, max_perf);
+}
+
+static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
+{
+	int max_perf, min_perf;
+
+	intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
+
+	pstate = clamp_t(int, pstate, min_perf, max_perf);
+
+	if (pstate == cpu->pstate.current_pstate)
+		return;
+
+#ifndef MODULE
+	trace_cpu_frequency(pstate * 100000, cpu->cpu);
+#endif
+	cpu->pstate.current_pstate = pstate;
+	wrmsrl(MSR_IA32_PERF_CTL, pstate << 8);
+
+}
+
+static inline void intel_pstate_pstate_increase(struct cpudata *cpu, int steps)
+{
+	int target;
+	target = cpu->pstate.current_pstate + steps;
+
+	intel_pstate_set_pstate(cpu, target);
+}
+
+static inline void intel_pstate_pstate_decrease(struct cpudata *cpu, int steps)
+{
+	int target;
+	target = cpu->pstate.current_pstate - steps;
+	intel_pstate_set_pstate(cpu, target);
+}
+
+static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
+{
+	sprintf(cpu->name, "Intel 2nd generation core");
+
+	cpu->pstate.min_pstate = intel_pstate_min_pstate();
+	cpu->pstate.max_pstate = intel_pstate_max_pstate();
+	cpu->pstate.turbo_pstate = intel_pstate_turbo_pstate();
+
+	/*
+	 * goto max pstate so we don't slow up boot if we are built-in if we are
+	 * a module we will take care of it during normal operation
+	 */
+	intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
+}
+
+static inline void intel_pstate_calc_busy(struct cpudata *cpu,
+					struct sample *sample)
+{
+	u64 core_pct;
+	sample->pstate_pct_busy = 100 - div64_u64(
+					sample->idletime_us * 100,
+					sample->duration_us);
+	core_pct = div64_u64(sample->aperf * 100, sample->mperf);
+	sample->freq = cpu->pstate.turbo_pstate * core_pct * 1000;
+
+	sample->core_pct_busy = div_s64((sample->pstate_pct_busy * core_pct),
+					100);
+}
+
+static inline void intel_pstate_sample(struct cpudata *cpu)
+{
+	ktime_t now;
+	u64 idle_time_us;
+	u64 aperf, mperf;
+
+	now = ktime_get();
+	idle_time_us = get_cpu_idle_time_us(cpu->cpu, NULL);
+
+	rdmsrl(MSR_IA32_APERF, aperf);
+	rdmsrl(MSR_IA32_MPERF, mperf);
+	/* for the first sample, don't actually record a sample, just
+	 * set the baseline */
+	if (cpu->prev_idle_time_us > 0) {
+		cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
+		cpu->samples[cpu->sample_ptr].start_time = cpu->prev_sample;
+		cpu->samples[cpu->sample_ptr].end_time = now;
+		cpu->samples[cpu->sample_ptr].duration_us =
+			ktime_us_delta(now, cpu->prev_sample);
+		cpu->samples[cpu->sample_ptr].idletime_us =
+			idle_time_us - cpu->prev_idle_time_us;
+
+		cpu->samples[cpu->sample_ptr].aperf = aperf;
+		cpu->samples[cpu->sample_ptr].mperf = mperf;
+		cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
+		cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
+
+		intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
+	}
+
+	cpu->prev_sample = now;
+	cpu->prev_idle_time_us = idle_time_us;
+	cpu->prev_aperf = aperf;
+	cpu->prev_mperf = mperf;
+}
+
+static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
+{
+	int sample_time, delay;
+
+	sample_time = cpu->pstate_policy->sample_rate_ms;
+	delay = msecs_to_jiffies(sample_time);
+	delay -= jiffies % delay;
+	mod_timer_pinned(&cpu->timer, jiffies + delay);
+}
+
+static inline void intel_pstate_idle_mode(struct cpudata *cpu)
+{
+	cpu->idle_mode = 1;
+}
+
+static inline void intel_pstate_normal_mode(struct cpudata *cpu)
+{
+	cpu->idle_mode = 0;
+}
+
+static inline int intel_pstate_get_scaled_busy(struct cpudata *cpu)
+{
+	int32_t busy_scaled;
+	int32_t core_busy, turbo_pstate, current_pstate;
+
+	core_busy = int_tofp(cpu->samples[cpu->sample_ptr].core_pct_busy);
+	turbo_pstate = int_tofp(cpu->pstate.turbo_pstate);
+	current_pstate = int_tofp(cpu->pstate.current_pstate);
+	busy_scaled = mul_fp(core_busy, div_fp(turbo_pstate, current_pstate));
+
+	return fp_toint(busy_scaled);
+}
+
+static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
+{
+	int busy_scaled;
+	struct _pid *pid;
+	signed int ctl = 0;
+	int steps;
+
+	pid = &cpu->pid;
+	busy_scaled = intel_pstate_get_scaled_busy(cpu);
+
+	ctl = pid_calc(pid, busy_scaled);
+
+	steps = abs(ctl);
+	if (ctl < 0)
+		intel_pstate_pstate_increase(cpu, steps);
+	else
+		intel_pstate_pstate_decrease(cpu, steps);
+}
+
+static inline void intel_pstate_adjust_idle_pstate(struct cpudata *cpu)
+{
+	int busy_scaled;
+	struct _pid *pid;
+	int ctl = 0;
+	int steps;
+
+	pid = &cpu->idle_pid;
+
+	busy_scaled = intel_pstate_get_scaled_busy(cpu);
+
+	ctl = pid_calc(pid, 100 - busy_scaled);
+
+	steps = abs(ctl);
+	if (ctl < 0)
+		intel_pstate_pstate_decrease(cpu, steps);
+	else
+		intel_pstate_pstate_increase(cpu, steps);
+
+	if (cpu->pstate.current_pstate == cpu->pstate.min_pstate)
+		intel_pstate_normal_mode(cpu);
+}
+
+static void intel_pstate_timer_func(unsigned long __data)
+{
+	struct cpudata *cpu = (struct cpudata *) __data;
+
+	intel_pstate_sample(cpu);
+
+	if (!cpu->idle_mode)
+		intel_pstate_adjust_busy_pstate(cpu);
+	else
+		intel_pstate_adjust_idle_pstate(cpu);
+
+#if defined(XPERF_FIX)
+	if (cpu->pstate.current_pstate == cpu->pstate.min_pstate) {
+		cpu->min_pstate_count++;
+		if (!(cpu->min_pstate_count % 5)) {
+			intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
+			intel_pstate_idle_mode(cpu);
+		}
+	} else
+		cpu->min_pstate_count = 0;
+#endif
+	intel_pstate_set_sample_time(cpu);
+}
+
+#define ICPU(model, policy) \
+	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&policy }
+
+static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
+	ICPU(0x2a, default_policy),
+	ICPU(0x2d, default_policy),
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
+
+static int intel_pstate_init_cpu(unsigned int cpunum)
+{
+
+	const struct x86_cpu_id *id;
+	struct cpudata *cpu;
+
+	id = x86_match_cpu(intel_pstate_cpu_ids);
+	if (!id)
+		return -ENODEV;
+
+	all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
+	if (!all_cpu_data[cpunum])
+		return -ENOMEM;
+
+	cpu = all_cpu_data[cpunum];
+
+	intel_pstate_get_cpu_pstates(cpu);
+
+	cpu->cpu = cpunum;
+	cpu->pstate_policy =
+		(struct pstate_adjust_policy *)id->driver_data;
+	init_timer_deferrable(&cpu->timer);
+	cpu->timer.function = intel_pstate_timer_func;
+	cpu->timer.data =
+		(unsigned long)cpu;
+	cpu->timer.expires = jiffies + HZ/100;
+	intel_pstate_busy_pid_reset(cpu);
+	intel_pstate_idle_pid_reset(cpu);
+	intel_pstate_sample(cpu);
+	intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
+
+	add_timer_on(&cpu->timer, cpunum);
+
+	pr_info("Intel pstate controlling: cpu %d\n", cpunum);
+
+	return 0;
+}
+
+static unsigned int intel_pstate_get(unsigned int cpu_num)
+{
+	struct sample *sample;
+	struct cpudata *cpu;
+
+	cpu = all_cpu_data[cpu_num];
+	if (!cpu)
+		return 0;
+	sample = &cpu->samples[cpu->sample_ptr];
+	return sample->freq;
+}
+
+static int intel_pstate_set_policy(struct cpufreq_policy *policy)
+{
+	struct cpudata *cpu;
+	int min, max;
+
+	cpu = all_cpu_data[policy->cpu];
+
+	intel_pstate_get_min_max(cpu, &min, &max);
+
+	limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
+	limits.min_perf_pct = clamp_t(int, limits.min_perf_pct, 0 , 100);
+	limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
+
+	limits.max_perf_pct = policy->max * 100 / policy->cpuinfo.max_freq;
+	limits.max_perf_pct = clamp_t(int, limits.max_perf_pct, 0 , 100);
+	limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
+
+	if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
+		limits.min_perf_pct = 100;
+		limits.min_perf = int_tofp(1);
+		limits.max_perf_pct = 100;
+		limits.max_perf = int_tofp(1);
+		limits.no_turbo = 0;
+	}
+
+	return 0;
+}
+
+static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
+{
+	cpufreq_verify_within_limits(policy,
+				policy->cpuinfo.min_freq,
+				policy->cpuinfo.max_freq);
+
+	if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
+		(policy->policy != CPUFREQ_POLICY_PERFORMANCE))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __cpuinit intel_pstate_cpu_exit(struct cpufreq_policy *policy)
+{
+	int cpu = policy->cpu;
+
+	del_timer(&all_cpu_data[cpu]->timer);
+	kfree(all_cpu_data[cpu]);
+	all_cpu_data[cpu] = NULL;
+	return 0;
+}
+
+static int __cpuinit intel_pstate_cpu_init(struct cpufreq_policy *policy)
+{
+	int rc, min_pstate, max_pstate;
+	struct cpudata *cpu;
+
+	rc = intel_pstate_init_cpu(policy->cpu);
+	if (rc)
+		return rc;
+
+	cpu = all_cpu_data[policy->cpu];
+
+	if (!limits.no_turbo &&
+		limits.min_perf_pct == 100 && limits.max_perf_pct == 100)
+		policy->policy = CPUFREQ_POLICY_PERFORMANCE;
+	else
+		policy->policy = CPUFREQ_POLICY_POWERSAVE;
+
+	intel_pstate_get_min_max(cpu, &min_pstate, &max_pstate);
+	policy->min = min_pstate * 100000;
+	policy->max = max_pstate * 100000;
+
+	/* cpuinfo and default policy values */
+	policy->cpuinfo.min_freq = cpu->pstate.min_pstate * 100000;
+	policy->cpuinfo.max_freq = cpu->pstate.turbo_pstate * 100000;
+	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+	cpumask_set_cpu(policy->cpu, policy->cpus);
+
+	return 0;
+}
+
+static struct cpufreq_driver intel_pstate_driver = {
+	.flags		= CPUFREQ_CONST_LOOPS,
+	.verify		= intel_pstate_verify_policy,
+	.setpolicy	= intel_pstate_set_policy,
+	.get		= intel_pstate_get,
+	.init		= intel_pstate_cpu_init,
+	.exit		= intel_pstate_cpu_exit,
+	.name		= "intel_pstate",
+	.owner		= THIS_MODULE,
+};
+
+static void intel_pstate_exit(void)
+{
+	int cpu;
+
+	sysfs_remove_group(intel_pstate_kobject,
+				&intel_pstate_attr_group);
+	debugfs_remove_recursive(debugfs_parent);
+
+	cpufreq_unregister_driver(&intel_pstate_driver);
+
+	if (!all_cpu_data)
+		return;
+
+	get_online_cpus();
+	for_each_online_cpu(cpu) {
+		if (all_cpu_data[cpu]) {
+			del_timer_sync(&all_cpu_data[cpu]->timer);
+			kfree(all_cpu_data[cpu]);
+		}
+	}
+
+	put_online_cpus();
+	vfree(all_cpu_data);
+}
+module_exit(intel_pstate_exit);
+
+static int __init intel_pstate_init(void)
+{
+	int rc = 0;
+	const struct x86_cpu_id *id;
+
+	id = x86_match_cpu(intel_pstate_cpu_ids);
+	if (!id)
+		return -ENODEV;
+
+	pr_info("Intel P-state driver initializing.\n");
+
+	all_cpu_data = vmalloc(sizeof(void *) * num_possible_cpus());
+	if (!all_cpu_data)
+		return -ENOMEM;
+	memset(all_cpu_data, 0, sizeof(void *) * num_possible_cpus());
+
+	rc = cpufreq_register_driver(&intel_pstate_driver);
+	if (rc)
+		goto out;
+
+	intel_pstate_debug_expose_params();
+	intel_pstate_sysfs_expose_params();
+	return rc;
+out:
+	intel_pstate_exit();
+	return -ENODEV;
+}
+device_initcall(intel_pstate_init);
+
+MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@intel.com>");
+MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
+MODULE_LICENSE("GPL");
diff --git a/drivers/cpufreq/kirkwood-cpufreq.c b/drivers/cpufreq/kirkwood-cpufreq.c
new file mode 100644
index 000000000000..0e83e3c24f5b
--- /dev/null
+++ b/drivers/cpufreq/kirkwood-cpufreq.c
@@ -0,0 +1,259 @@
+/*
+ *	kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
+ *
+ *	Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/cpufreq.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <asm/proc-fns.h>
+
+#define CPU_SW_INT_BLK BIT(28)
+
+static struct priv
+{
+	struct clk *cpu_clk;
+	struct clk *ddr_clk;
+	struct clk *powersave_clk;
+	struct device *dev;
+	void __iomem *base;
+} priv;
+
+#define STATE_CPU_FREQ 0x01
+#define STATE_DDR_FREQ 0x02
+
+/*
+ * Kirkwood can swap the clock to the CPU between two clocks:
+ *
+ * - cpu clk
+ * - ddr clk
+ *
+ * The frequencies are set at runtime before registering this *
+ * table.
+ */
+static struct cpufreq_frequency_table kirkwood_freq_table[] = {
+	{STATE_CPU_FREQ,	0}, /* CPU uses cpuclk */
+	{STATE_DDR_FREQ,	0}, /* CPU uses ddrclk */
+	{0,			CPUFREQ_TABLE_END},
+};
+
+static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
+{
+	if (__clk_is_enabled(priv.powersave_clk))
+		return kirkwood_freq_table[1].frequency;
+	return kirkwood_freq_table[0].frequency;
+}
+
+static void kirkwood_cpufreq_set_cpu_state(unsigned int index)
+{
+	struct cpufreq_freqs freqs;
+	unsigned int state = kirkwood_freq_table[index].index;
+	unsigned long reg;
+
+	freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
+	freqs.new = kirkwood_freq_table[index].frequency;
+	freqs.cpu = 0; /* Kirkwood is UP */
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	dev_dbg(priv.dev, "Attempting to set frequency to %i KHz\n",
+		kirkwood_freq_table[index].frequency);
+	dev_dbg(priv.dev, "old frequency was %i KHz\n",
+		kirkwood_cpufreq_get_cpu_frequency(0));
+
+	if (freqs.old != freqs.new) {
+		local_irq_disable();
+
+		/* Disable interrupts to the CPU */
+		reg = readl_relaxed(priv.base);
+		reg |= CPU_SW_INT_BLK;
+		writel_relaxed(reg, priv.base);
+
+		switch (state) {
+		case STATE_CPU_FREQ:
+			clk_disable(priv.powersave_clk);
+			break;
+		case STATE_DDR_FREQ:
+			clk_enable(priv.powersave_clk);
+			break;
+		}
+
+		/* Wait-for-Interrupt, while the hardware changes frequency */
+		cpu_do_idle();
+
+		/* Enable interrupts to the CPU */
+		reg = readl_relaxed(priv.base);
+		reg &= ~CPU_SW_INT_BLK;
+		writel_relaxed(reg, priv.base);
+
+		local_irq_enable();
+	}
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+};
+
+static int kirkwood_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, kirkwood_freq_table);
+}
+
+static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
+			    unsigned int target_freq,
+			    unsigned int relation)
+{
+	unsigned int index = 0;
+
+	if (cpufreq_frequency_table_target(policy, kirkwood_freq_table,
+				target_freq, relation, &index))
+		return -EINVAL;
+
+	kirkwood_cpufreq_set_cpu_state(index);
+
+	return 0;
+}
+
+/* Module init and exit code */
+static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	int result;
+
+	/* cpuinfo and default policy values */
+	policy->cpuinfo.transition_latency = 5000; /* 5uS */
+	policy->cur = kirkwood_cpufreq_get_cpu_frequency(0);
+
+	result = cpufreq_frequency_table_cpuinfo(policy, kirkwood_freq_table);
+	if (result)
+		return result;
+
+	cpufreq_frequency_table_get_attr(kirkwood_freq_table, policy->cpu);
+
+	return 0;
+}
+
+static int kirkwood_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+	cpufreq_frequency_table_put_attr(policy->cpu);
+	return 0;
+}
+
+static struct freq_attr *kirkwood_cpufreq_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+
+static struct cpufreq_driver kirkwood_cpufreq_driver = {
+	.get	= kirkwood_cpufreq_get_cpu_frequency,
+	.verify	= kirkwood_cpufreq_verify,
+	.target	= kirkwood_cpufreq_target,
+	.init	= kirkwood_cpufreq_cpu_init,
+	.exit	= kirkwood_cpufreq_cpu_exit,
+	.name	= "kirkwood-cpufreq",
+	.owner	= THIS_MODULE,
+	.attr	= kirkwood_cpufreq_attr,
+};
+
+static int kirkwood_cpufreq_probe(struct platform_device *pdev)
+{
+	struct device_node *np;
+	struct resource *res;
+	int err;
+
+	priv.dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Cannot get memory resource\n");
+		return -ENODEV;
+	}
+	priv.base = devm_request_and_ioremap(&pdev->dev, res);
+	if (!priv.base) {
+		dev_err(&pdev->dev, "Cannot ioremap\n");
+		return -EADDRNOTAVAIL;
+	}
+
+	np = of_find_node_by_path("/cpus/cpu@0");
+	if (!np)
+		return -ENODEV;
+
+	priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
+	if (IS_ERR(priv.cpu_clk)) {
+		dev_err(priv.dev, "Unable to get cpuclk");
+		return PTR_ERR(priv.cpu_clk);
+	}
+
+	clk_prepare_enable(priv.cpu_clk);
+	kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;
+
+	priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
+	if (IS_ERR(priv.ddr_clk)) {
+		dev_err(priv.dev, "Unable to get ddrclk");
+		err = PTR_ERR(priv.ddr_clk);
+		goto out_cpu;
+	}
+
+	clk_prepare_enable(priv.ddr_clk);
+	kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;
+
+	priv.powersave_clk = of_clk_get_by_name(np, "powersave");
+	if (IS_ERR(priv.powersave_clk)) {
+		dev_err(priv.dev, "Unable to get powersave");
+		err = PTR_ERR(priv.powersave_clk);
+		goto out_ddr;
+	}
+	clk_prepare(priv.powersave_clk);
+
+	of_node_put(np);
+	np = NULL;
+
+	err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
+	if (!err)
+		return 0;
+
+	dev_err(priv.dev, "Failed to register cpufreq driver");
+
+	clk_disable_unprepare(priv.powersave_clk);
+out_ddr:
+	clk_disable_unprepare(priv.ddr_clk);
+out_cpu:
+	clk_disable_unprepare(priv.cpu_clk);
+	of_node_put(np);
+
+	return err;
+}
+
+static int kirkwood_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_driver(&kirkwood_cpufreq_driver);
+
+	clk_disable_unprepare(priv.powersave_clk);
+	clk_disable_unprepare(priv.ddr_clk);
+	clk_disable_unprepare(priv.cpu_clk);
+
+	return 0;
+}
+
+static struct platform_driver kirkwood_cpufreq_platform_driver = {
+	.probe = kirkwood_cpufreq_probe,
+	.remove = kirkwood_cpufreq_remove,
+	.driver = {
+		.name = "kirkwood-cpufreq",
+		.owner = THIS_MODULE,
+	},
+};
+
+module_platform_driver(kirkwood_cpufreq_platform_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
+MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
+MODULE_ALIAS("platform:kirkwood-cpufreq");
diff --git a/drivers/cpufreq/maple-cpufreq.c b/drivers/cpufreq/maple-cpufreq.c
index 89b178a3f849..d4c4989823dc 100644
--- a/drivers/cpufreq/maple-cpufreq.c
+++ b/drivers/cpufreq/maple-cpufreq.c
@@ -181,7 +181,7 @@ static int maple_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	/* secondary CPUs are tied to the primary one by the
 	 * cpufreq core if in the secondary policy we tell it that
 	 * it actually must be one policy together with all others. */
-	cpumask_copy(policy->cpus, cpu_online_mask);
+	cpumask_setall(policy->cpus);
 	cpufreq_frequency_table_get_attr(maple_cpu_freqs, policy->cpu);
 
 	return cpufreq_frequency_table_cpuinfo(policy,
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index 97102b05843f..9128c07bafba 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -214,10 +214,8 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 	 * interface to handle this scenario. Additional is_smp() check
 	 * is to keep SMP_ON_UP build working.
 	 */
-	if (is_smp()) {
-		policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
+	if (is_smp())
 		cpumask_setall(policy->cpus);
-	}
 
 	/* FIXME: what's the actual transition time? */
 	policy->cpuinfo.transition_latency = 300 * 1000;
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 056faf6af1a9..d13a13678b5f 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1249,39 +1249,59 @@ static struct cpufreq_driver cpufreq_amd64_driver = {
 	.attr		= powernow_k8_attr,
 };
 
+static void __request_acpi_cpufreq(void)
+{
+	const char *cur_drv, *drv = "acpi-cpufreq";
+
+	cur_drv = cpufreq_get_current_driver();
+	if (!cur_drv)
+		goto request;
+
+	if (strncmp(cur_drv, drv, min_t(size_t, strlen(cur_drv), strlen(drv))))
+		pr_warn(PFX "WTF driver: %s\n", cur_drv);
+
+	return;
+
+ request:
+	pr_warn(PFX "This CPU is not supported anymore, using acpi-cpufreq instead.\n");
+	request_module(drv);
+}
+
 /* driver entry point for init */
 static int __cpuinit powernowk8_init(void)
 {
 	unsigned int i, supported_cpus = 0;
-	int rv;
+	int ret;
 
 	if (static_cpu_has(X86_FEATURE_HW_PSTATE)) {
-		pr_warn(PFX "this CPU is not supported anymore, using acpi-cpufreq instead.\n");
-		request_module("acpi-cpufreq");
+		__request_acpi_cpufreq();
 		return -ENODEV;
 	}
 
 	if (!x86_match_cpu(powernow_k8_ids))
 		return -ENODEV;
 
+	get_online_cpus();
 	for_each_online_cpu(i) {
-		int rc;
-		smp_call_function_single(i, check_supported_cpu, &rc, 1);
-		if (rc == 0)
+		smp_call_function_single(i, check_supported_cpu, &ret, 1);
+		if (!ret)
 			supported_cpus++;
 	}
 
-	if (supported_cpus != num_online_cpus())
+	if (supported_cpus != num_online_cpus()) {
+		put_online_cpus();
 		return -ENODEV;
+	}
+	put_online_cpus();
 
-	rv = cpufreq_register_driver(&cpufreq_amd64_driver);
+	ret = cpufreq_register_driver(&cpufreq_amd64_driver);
+	if (ret)
+		return ret;
 
-	if (!rv)
-		pr_info(PFX "Found %d %s (%d cpu cores) (" VERSION ")\n",
-			num_online_nodes(), boot_cpu_data.x86_model_id,
-			supported_cpus);
+	pr_info(PFX "Found %d %s (%d cpu cores) (" VERSION ")\n",
+		num_online_nodes(), boot_cpu_data.x86_model_id, supported_cpus);
 
-	return rv;
+	return ret;
 }
 
 /* driver entry point for term */
diff --git a/drivers/cpufreq/spear-cpufreq.c b/drivers/cpufreq/spear-cpufreq.c
index 4575cfe41755..7e4d77327957 100644
--- a/drivers/cpufreq/spear-cpufreq.c
+++ b/drivers/cpufreq/spear-cpufreq.c
@@ -30,7 +30,7 @@ static struct {
 	u32 cnt;
 } spear_cpufreq;
 
-int spear_cpufreq_verify(struct cpufreq_policy *policy)
+static int spear_cpufreq_verify(struct cpufreq_policy *policy)
 {
 	return cpufreq_frequency_table_verify(policy, spear_cpufreq.freq_tbl);
 }
@@ -157,7 +157,9 @@ static int spear_cpufreq_target(struct cpufreq_policy *policy,
 
 	freqs.new = newfreq / 1000;
 	freqs.new /= mult;
-	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	for_each_cpu(freqs.cpu, policy->cpus)
+		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 
 	if (mult == 2)
 		ret = spear1340_set_cpu_rate(srcclk, newfreq);
@@ -170,7 +172,8 @@ static int spear_cpufreq_target(struct cpufreq_policy *policy,
 		freqs.new = clk_get_rate(spear_cpufreq.clk) / 1000;
 	}
 
-	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+	for_each_cpu(freqs.cpu, policy->cpus)
+		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 	return ret;
 }
 
@@ -188,8 +191,7 @@ static int spear_cpufreq_init(struct cpufreq_policy *policy)
 	policy->cpuinfo.transition_latency = spear_cpufreq.transition_latency;
 	policy->cur = spear_cpufreq_get(0);
 
-	cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
-	cpumask_copy(policy->related_cpus, policy->cpus);
+	cpumask_setall(policy->cpus);
 
 	return 0;
 }
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
new file mode 100644
index 000000000000..9545c9f03809
--- /dev/null
+++ b/drivers/mailbox/Kconfig
@@ -0,0 +1,19 @@
+menuconfig MAILBOX
+	bool "Mailbox Hardware Support"
+	help
+	  Mailbox is a framework to control hardware communication between
+	  on-chip processors through queued messages and interrupt driven
+	  signals. Say Y if your platform supports hardware mailboxes.
+
+if MAILBOX
+config PL320_MBOX
+	bool "ARM PL320 Mailbox"
+	depends on ARM_AMBA
+	help
+	  An implementation of the ARM PL320 Interprocessor Communication
+	  Mailbox (IPCM), tailored for the Calxeda Highbank. It is used to
+	  send short messages between Highbank's A9 cores and the EnergyCore
+	  Management Engine, primarily for cpufreq. Say Y here if you want
+	  to use the PL320 IPCM support.
+
+endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
new file mode 100644
index 000000000000..543ad6a79505
--- /dev/null
+++ b/drivers/mailbox/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
diff --git a/drivers/mailbox/pl320-ipc.c b/drivers/mailbox/pl320-ipc.c
new file mode 100644
index 000000000000..c45b3aedafba
--- /dev/null
+++ b/drivers/mailbox/pl320-ipc.c
@@ -0,0 +1,199 @@
+/*
+ * Copyright 2012 Calxeda, Inc.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/types.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/amba/bus.h>
+
+#include <linux/mailbox.h>
+
+#define IPCMxSOURCE(m)		((m) * 0x40)
+#define IPCMxDSET(m)		(((m) * 0x40) + 0x004)
+#define IPCMxDCLEAR(m)		(((m) * 0x40) + 0x008)
+#define IPCMxDSTATUS(m)		(((m) * 0x40) + 0x00C)
+#define IPCMxMODE(m)		(((m) * 0x40) + 0x010)
+#define IPCMxMSET(m)		(((m) * 0x40) + 0x014)
+#define IPCMxMCLEAR(m)		(((m) * 0x40) + 0x018)
+#define IPCMxMSTATUS(m)		(((m) * 0x40) + 0x01C)
+#define IPCMxSEND(m)		(((m) * 0x40) + 0x020)
+#define IPCMxDR(m, dr)		(((m) * 0x40) + ((dr) * 4) + 0x024)
+
+#define IPCMMIS(irq)		(((irq) * 8) + 0x800)
+#define IPCMRIS(irq)		(((irq) * 8) + 0x804)
+
+#define MBOX_MASK(n)		(1 << (n))
+#define IPC_TX_MBOX		1
+#define IPC_RX_MBOX		2
+
+#define CHAN_MASK(n)		(1 << (n))
+#define A9_SOURCE		1
+#define M3_SOURCE		0
+
+static void __iomem *ipc_base;
+static int ipc_irq;
+static DEFINE_MUTEX(ipc_m1_lock);
+static DECLARE_COMPLETION(ipc_completion);
+static ATOMIC_NOTIFIER_HEAD(ipc_notifier);
+
+static inline void set_destination(int source, int mbox)
+{
+	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxDSET(mbox));
+	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxMSET(mbox));
+}
+
+static inline void clear_destination(int source, int mbox)
+{
+	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxDCLEAR(mbox));
+	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxMCLEAR(mbox));
+}
+
+static void __ipc_send(int mbox, u32 *data)
+{
+	int i;
+	for (i = 0; i < 7; i++)
+		__raw_writel(data[i], ipc_base + IPCMxDR(mbox, i));
+	__raw_writel(0x1, ipc_base + IPCMxSEND(mbox));
+}
+
+static u32 __ipc_rcv(int mbox, u32 *data)
+{
+	int i;
+	for (i = 0; i < 7; i++)
+		data[i] = __raw_readl(ipc_base + IPCMxDR(mbox, i));
+	return data[1];
+}
+
+/* blocking implmentation from the A9 side, not usuable in interrupts! */
+int pl320_ipc_transmit(u32 *data)
+{
+	int ret;
+
+	mutex_lock(&ipc_m1_lock);
+
+	init_completion(&ipc_completion);
+	__ipc_send(IPC_TX_MBOX, data);
+	ret = wait_for_completion_timeout(&ipc_completion,
+					  msecs_to_jiffies(1000));
+	if (ret == 0) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	ret = __ipc_rcv(IPC_TX_MBOX, data);
+out:
+	mutex_unlock(&ipc_m1_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pl320_ipc_transmit);
+
+static irqreturn_t ipc_handler(int irq, void *dev)
+{
+	u32 irq_stat;
+	u32 data[7];
+
+	irq_stat = __raw_readl(ipc_base + IPCMMIS(1));
+	if (irq_stat & MBOX_MASK(IPC_TX_MBOX)) {
+		__raw_writel(0, ipc_base + IPCMxSEND(IPC_TX_MBOX));
+		complete(&ipc_completion);
+	}
+	if (irq_stat & MBOX_MASK(IPC_RX_MBOX)) {
+		__ipc_rcv(IPC_RX_MBOX, data);
+		atomic_notifier_call_chain(&ipc_notifier, data[0], data + 1);
+		__raw_writel(2, ipc_base + IPCMxSEND(IPC_RX_MBOX));
+	}
+
+	return IRQ_HANDLED;
+}
+
+int pl320_ipc_register_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&ipc_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(pl320_ipc_register_notifier);
+
+int pl320_ipc_unregister_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&ipc_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(pl320_ipc_unregister_notifier);
+
+static int __init pl320_probe(struct amba_device *adev,
+				const struct amba_id *id)
+{
+	int ret;
+
+	ipc_base = ioremap(adev->res.start, resource_size(&adev->res));
+	if (ipc_base == NULL)
+		return -ENOMEM;
+
+	__raw_writel(0, ipc_base + IPCMxSEND(IPC_TX_MBOX));
+
+	ipc_irq = adev->irq[0];
+	ret = request_irq(ipc_irq, ipc_handler, 0, dev_name(&adev->dev), NULL);
+	if (ret < 0)
+		goto err;
+
+	/* Init slow mailbox */
+	__raw_writel(CHAN_MASK(A9_SOURCE),
+			ipc_base + IPCMxSOURCE(IPC_TX_MBOX));
+	__raw_writel(CHAN_MASK(M3_SOURCE),
+			ipc_base + IPCMxDSET(IPC_TX_MBOX));
+	__raw_writel(CHAN_MASK(M3_SOURCE) | CHAN_MASK(A9_SOURCE),
+		     ipc_base + IPCMxMSET(IPC_TX_MBOX));
+
+	/* Init receive mailbox */
+	__raw_writel(CHAN_MASK(M3_SOURCE),
+			ipc_base + IPCMxSOURCE(IPC_RX_MBOX));
+	__raw_writel(CHAN_MASK(A9_SOURCE),
+			ipc_base + IPCMxDSET(IPC_RX_MBOX));
+	__raw_writel(CHAN_MASK(M3_SOURCE) | CHAN_MASK(A9_SOURCE),
+		     ipc_base + IPCMxMSET(IPC_RX_MBOX));
+
+	return 0;
+err:
+	iounmap(ipc_base);
+	return ret;
+}
+
+static struct amba_id pl320_ids[] = {
+	{
+		.id	= 0x00041320,
+		.mask	= 0x000fffff,
+	},
+	{ 0, 0 },
+};
+
+static struct amba_driver pl320_driver = {
+	.drv = {
+		.name	= "pl320",
+	},
+	.id_table	= pl320_ids,
+	.probe		= pl320_probe,
+};
+
+static int __init ipc_init(void)
+{
+	return amba_driver_register(&pl320_driver);
+}
+module_init(ipc_init);