Merge tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI updates from Rafael Wysocki:
 "This time the total number of ACPI commits is slightly greater than
  the number of cpufreq commits, but Viresh Kumar (who works on cpufreq)
  remains the most active patch submitter.

  To me, the most significant change is the addition of offline/online
  device operations to the driver core (with the Greg's blessing) and
  the related modifications of the ACPI core hotplug code.  Next are the
  freezer updates from Colin Cross that should make the freezing of
  tasks a bit less heavy weight.

  We also have a couple of regression fixes, a number of fixes for
  issues that have not been identified as regressions, two new drivers
  and a bunch of cleanups all over.

  Highlights:

   - Hotplug changes to support graceful hot-removal failures.

     It sometimes is necessary to fail device hot-removal operations
     gracefully if they cannot be carried out completely.  For example,
     if memory from a memory module being hot-removed has been allocated
     for the kernel's own use and cannot be moved elsewhere, it's
     desirable to fail the hot-removal operation in a graceful way
     rather than to crash the kernel, but currenty a success or a kernel
     crash are the only possible outcomes of an attempted memory
     hot-removal.  Needless to say, that is not a very attractive
     alternative and it had to be addressed.

     However, in order to make it work for memory, I first had to make
     it work for CPUs and for this purpose I needed to modify the ACPI
     processor driver.  It's been split into two parts, a resident one
     handling the low-level initialization/cleanup and a modular one
     playing the actual driver's role (but it binds to the CPU system
     device objects rather than to the ACPI device objects representing
     processors).  That's been sort of like a live brain surgery on a
     patient who's riding a bike.

     So this is a little scary, but since we found and fixed a couple of
     regressions it caused to happen during the early linux-next testing
     (a month ago), nobody has complained.

     As a bonus we remove some duplicated ACPI hotplug code, because the
     ACPI-based CPU hotplug is now going to use the common ACPI hotplug
     code.

   - Lighter weight freezing of tasks.

     These changes from Colin Cross and Mandeep Singh Baines are
     targeted at making the freezing of tasks a bit less heavy weight
     operation.  They reduce the number of tasks woken up every time
     during the freezing, by using the observation that the freezer
     simply doesn't need to wake up some of them and wait for them all
     to call refrigerator().  The time needed for the freezer to decide
     to report a failure is reduced too.

     Also reintroduced is the check causing a lockdep warining to
     trigger when try_to_freeze() is called with locks held (which is
     generally unsafe and shouldn't happen).

   - cpufreq updates

     First off, a commit from Srivatsa S Bhat fixes a resume regression
     introduced during the 3.10 cycle causing some cpufreq sysfs
     attributes to return wrong values to user space after resume.  The
     fix is kind of fresh, but also it's pretty obvious once Srivatsa
     has identified the root cause.

     Second, we have a new freqdomain_cpus sysfs attribute for the
     acpi-cpufreq driver to provide information previously available via
     related_cpus.  From Lan Tianyu.

     Finally, we fix a number of issues, mostly related to the
     CPUFREQ_POSTCHANGE notifier and cpufreq Kconfig options and clean
     up some code.  The majority of changes from Viresh Kumar with bits
     from Jacob Shin, Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia,
     Arnd Bergmann, and Tang Yuantian.

   - ACPICA update

     A usual bunch of updates from the ACPICA upstream.

     During the 3.4 cycle we introduced support for ACPI 5 extended
     sleep registers, but they are only supposed to be used if the
     HW-reduced mode bit is set in the FADT flags and the code attempted
     to use them without checking that bit.  That caused suspend/resume
     regressions to happen on some systems.  Fix from Lv Zheng causes
     those registers to be used only if the HW-reduced mode bit is set.

     Apart from this some other ACPICA bugs are fixed and code cleanups
     are made by Bob Moore, Tomasz Nowicki, Lv Zheng, Chao Guan, and
     Zhang Rui.

   - cpuidle updates

     New driver for Xilinx Zynq processors is added by Michal Simek.

     Multidriver support simplification, addition of some missing
     kerneldoc comments and Kconfig-related fixes come from Daniel
     Lezcano.

   - ACPI power management updates

     Changes to make suspend/resume work correctly in Xen guests from
     Konrad Rzeszutek Wilk, sparse warning fix from Fengguang Wu and
     cleanups and fixes of the ACPI device power state selection
     routine.

   - ACPI documentation updates

     Some previously missing pieces of ACPI documentation are added by
     Lv Zheng and Aaron Lu (hopefully, that will help people to
     uderstand how the ACPI subsystem works) and one outdated doc is
     updated by Hanjun Guo.

   - Assorted ACPI updates

     We finally nailed down the IA-64 issue that was the reason for
     reverting commit 9f29ab11ddbf ("ACPI / scan: do not match drivers
     against objects having scan handlers"), so we can fix it and move
     the ACPI scan handler check added to the ACPI video driver back to
     the core.

     A mechanism for adding CMOS RTC address space handlers is
     introduced by Lan Tianyu to allow some EC-related breakage to be
     fixed on some systems.

     A spec-compliant implementation of acpi_os_get_timer() is added by
     Mika Westerberg.

     The evaluation of _STA is added to do_acpi_find_child() to avoid
     situations in which a pointer to a disabled device object is
     returned instead of an enabled one with the same _ADR value.  From
     Jeff Wu.

     Intel BayTrail PCH (Platform Controller Hub) support is added to
     the ACPI driver for Intel Low-Power Subsystems (LPSS) and that
     driver is modified to work around a couple of known BIOS issues.
     Changes from Mika Westerberg and Heikki Krogerus.

     The EC driver is fixed by Vasiliy Kulikov to use get_user() and
     put_user() instead of dereferencing user space pointers blindly.

     Code cleanups are made by Bjorn Helgaas, Nicholas Mazzuca and Toshi
     Kani.

   - Assorted power management updates

     The "runtime idle" helper routine is changed to take the return
     values of the callbacks executed by it into account and to call
     rpm_suspend() if they return 0, which allows us to reduce the
     overall code bloat a bit (by dropping some code that's not
     necessary any more after that modification).

     The runtime PM documentation is updated by Alan Stern (to reflect
     the "runtime idle" behavior change).

     New trace points for PM QoS are added by Sahara
     (<keun-o.park@windriver.com>).

     PM QoS documentation is updated by Lan Tianyu.

     Code cleanups are made and minor issues are addressed by Bernie
     Thompson, Bjorn Helgaas, Julius Werner, and Shuah Khan.

   - devfreq updates

     New driver for the Exynos5-bus device from Abhilash Kesavan.

     Minor cleanups, fixes and MAINTAINERS update from MyungJoo Ham,
     Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and Wei Yongjun.

   - OMAP power management updates

     Adaptive Voltage Scaling (AVS) SmartReflex voltage control driver
     updates from Andrii Tseglytskyi and Nishanth Menon."

* tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
  cpufreq: Fix cpufreq regression after suspend/resume
  ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state()
  PM / Sleep: Warn about system time after resume with pm_trace
  cpufreq: don't leave stale policy pointer in cdbs->cur_policy
  acpi-cpufreq: Add new sysfs attribute freqdomain_cpus
  cpufreq: make sure frequency transitions are serialized
  ACPI: implement acpi_os_get_timer() according the spec
  ACPI / EC: Add HP Folio 13 to ec_dmi_table in order to skip DSDT scan
  ACPI: Add CMOS RTC Operation Region handler support
  ACPI / processor: Drop unused variable from processor_perflib.c
  cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases
  ...

1 files changed, 163 insertions, 60 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 2d53f47..6a015ad 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -3,6 +3,7 @@
  *
  *  Copyright (C) 2001 Russell King
  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
+ *            (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
  *
  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
  *	Added handling for CPU hotplug
@@ -12,12 +13,13 @@
  * 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.
- *
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <asm/cputime.h>
 #include <linux/kernel.h>
+#include <linux/kernel_stat.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/notifier.h>
@@ -25,6 +27,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/tick.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
@@ -41,11 +44,13 @@
  */
 static struct cpufreq_driver *cpufreq_driver;
 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
+static DEFINE_RWLOCK(cpufreq_driver_lock);
+static DEFINE_MUTEX(cpufreq_governor_lock);
+
 #ifdef CONFIG_HOTPLUG_CPU
 /* This one keeps track of the previously set governor of a removed CPU */
 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 #endif
-static DEFINE_RWLOCK(cpufreq_driver_lock);
 
 /*
  * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
@@ -132,6 +137,51 @@ bool have_governor_per_policy(void)
 {
 	return cpufreq_driver->have_governor_per_policy;
 }
+EXPORT_SYMBOL_GPL(have_governor_per_policy);
+
+struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
+{
+	if (have_governor_per_policy())
+		return &policy->kobj;
+	else
+		return cpufreq_global_kobject;
+}
+EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
+
+static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
+{
+	u64 idle_time;
+	u64 cur_wall_time;
+	u64 busy_time;
+
+	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
+
+	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
+
+	idle_time = cur_wall_time - busy_time;
+	if (wall)
+		*wall = cputime_to_usecs(cur_wall_time);
+
+	return cputime_to_usecs(idle_time);
+}
+
+u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
+{
+	u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
+
+	if (idle_time == -1ULL)
+		return get_cpu_idle_time_jiffy(cpu, wall);
+	else if (!io_busy)
+		idle_time += get_cpu_iowait_time_us(cpu, wall);
+
+	return idle_time;
+}
+EXPORT_SYMBOL_GPL(get_cpu_idle_time);
 
 static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
 {
@@ -150,7 +200,6 @@ static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
 	if (!try_module_get(cpufreq_driver->owner))
 		goto err_out_unlock;
 
-
 	/* get the CPU */
 	data = per_cpu(cpufreq_cpu_data, cpu);
 
@@ -220,7 +269,7 @@ static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *data)
  */
 #ifndef CONFIG_SMP
 static unsigned long l_p_j_ref;
-static unsigned int  l_p_j_ref_freq;
+static unsigned int l_p_j_ref_freq;
 
 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 {
@@ -233,7 +282,7 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 		pr_debug("saving %lu as reference value for loops_per_jiffy; "
 			"freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
 	}
-	if ((val == CPUFREQ_POSTCHANGE  && ci->old != ci->new) ||
+	if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
 	    (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
 		loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
 								ci->new);
@@ -248,8 +297,7 @@ static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 }
 #endif
 
-
-void __cpufreq_notify_transition(struct cpufreq_policy *policy,
+static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 		struct cpufreq_freqs *freqs, unsigned int state)
 {
 	BUG_ON(irqs_disabled());
@@ -264,6 +312,12 @@ void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 	switch (state) {
 
 	case CPUFREQ_PRECHANGE:
+		if (WARN(policy->transition_ongoing,
+				"In middle of another frequency transition\n"))
+			return;
+
+		policy->transition_ongoing = true;
+
 		/* detect if the driver reported a value as "old frequency"
 		 * which is not equal to what the cpufreq core thinks is
 		 * "old frequency".
@@ -283,6 +337,12 @@ void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 		break;
 
 	case CPUFREQ_POSTCHANGE:
+		if (WARN(!policy->transition_ongoing,
+				"No frequency transition in progress\n"))
+			return;
+
+		policy->transition_ongoing = false;
+
 		adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 		pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
 			(unsigned long)freqs->cpu);
@@ -294,6 +354,7 @@ void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 		break;
 	}
 }
+
 /**
  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
  * on frequency transition.
@@ -311,7 +372,6 @@ void cpufreq_notify_transition(struct cpufreq_policy *policy,
 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
 
 
-
 /*********************************************************************
  *                          SYSFS INTERFACE                          *
  *********************************************************************/
@@ -376,7 +436,6 @@ out:
 	return err;
 }
 
-
 /**
  * cpufreq_per_cpu_attr_read() / show_##file_name() -
  * print out cpufreq information
@@ -441,7 +500,6 @@ static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
 	return sprintf(buf, "%u\n", cur_freq);
 }
 
-
 /**
  * show_scaling_governor - show the current policy for the specified CPU
  */
@@ -457,7 +515,6 @@ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
 	return -EINVAL;
 }
 
-
 /**
  * store_scaling_governor - store policy for the specified CPU
  */
@@ -480,8 +537,10 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 						&new_policy.governor))
 		return -EINVAL;
 
-	/* Do not use cpufreq_set_policy here or the user_policy.max
-	   will be wrongly overridden */
+	/*
+	 * Do not use cpufreq_set_policy here or the user_policy.max
+	 * will be wrongly overridden
+	 */
 	ret = __cpufreq_set_policy(policy, &new_policy);
 
 	policy->user_policy.policy = policy->policy;
@@ -526,7 +585,7 @@ out:
 	return i;
 }
 
-static ssize_t show_cpus(const struct cpumask *mask, char *buf)
+ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
 {
 	ssize_t i = 0;
 	unsigned int cpu;
@@ -541,6 +600,7 @@ static ssize_t show_cpus(const struct cpumask *mask, char *buf)
 	i += sprintf(&buf[i], "\n");
 	return i;
 }
+EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
 
 /**
  * show_related_cpus - show the CPUs affected by each transition even if
@@ -548,7 +608,7 @@ static ssize_t show_cpus(const struct cpumask *mask, char *buf)
  */
 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
 {
-	return show_cpus(policy->related_cpus, buf);
+	return cpufreq_show_cpus(policy->related_cpus, buf);
 }
 
 /**
@@ -556,7 +616,7 @@ static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
  */
 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
 {
-	return show_cpus(policy->cpus, buf);
+	return cpufreq_show_cpus(policy->cpus, buf);
 }
 
 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
@@ -630,9 +690,6 @@ static struct attribute *default_attrs[] = {
 	NULL
 };
 
-struct kobject *cpufreq_global_kobject;
-EXPORT_SYMBOL(cpufreq_global_kobject);
-
 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 #define to_attr(a) container_of(a, struct freq_attr, attr)
 
@@ -703,6 +760,49 @@ static struct kobj_type ktype_cpufreq = {
 	.release	= cpufreq_sysfs_release,
 };
 
+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
+static int cpufreq_global_kobject_usage;
+
+int cpufreq_get_global_kobject(void)
+{
+	if (!cpufreq_global_kobject_usage++)
+		return kobject_add(cpufreq_global_kobject,
+				&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
+
+	return 0;
+}
+EXPORT_SYMBOL(cpufreq_get_global_kobject);
+
+void cpufreq_put_global_kobject(void)
+{
+	if (!--cpufreq_global_kobject_usage)
+		kobject_del(cpufreq_global_kobject);
+}
+EXPORT_SYMBOL(cpufreq_put_global_kobject);
+
+int cpufreq_sysfs_create_file(const struct attribute *attr)
+{
+	int ret = cpufreq_get_global_kobject();
+
+	if (!ret) {
+		ret = sysfs_create_file(cpufreq_global_kobject, attr);
+		if (ret)
+			cpufreq_put_global_kobject();
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
+
+void cpufreq_sysfs_remove_file(const struct attribute *attr)
+{
+	sysfs_remove_file(cpufreq_global_kobject, attr);
+	cpufreq_put_global_kobject();
+}
+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
+
 /* symlink affected CPUs */
 static int cpufreq_add_dev_symlink(unsigned int cpu,
 				   struct cpufreq_policy *policy)
@@ -1005,7 +1105,8 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
  * Caller should already have policy_rwsem in write mode for this CPU.
  * This routine frees the rwsem before returning.
  */
-static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
+static int __cpufreq_remove_dev(struct device *dev,
+		struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id, ret, cpus;
 	unsigned long flags;
@@ -1112,7 +1213,6 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif
 	return 0;
 }
 
-
 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id;
@@ -1125,7 +1225,6 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 	return retval;
 }
 
-
 static void handle_update(struct work_struct *work)
 {
 	struct cpufreq_policy *policy =
@@ -1136,7 +1235,8 @@ static void handle_update(struct work_struct *work)
 }
 
 /**
- *	cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
+ *	cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
+ *	in deep trouble.
  *	@cpu: cpu number
  *	@old_freq: CPU frequency the kernel thinks the CPU runs at
  *	@new_freq: CPU frequency the CPU actually runs at
@@ -1151,7 +1251,6 @@ static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
 	struct cpufreq_freqs freqs;
 	unsigned long flags;
 
-
 	pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
 	       "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
 
@@ -1166,7 +1265,6 @@ static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 }
 
-
 /**
  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
  * @cpu: CPU number
@@ -1212,7 +1310,6 @@ unsigned int cpufreq_quick_get_max(unsigned int cpu)
 }
 EXPORT_SYMBOL(cpufreq_quick_get_max);
 
-
 static unsigned int __cpufreq_get(unsigned int cpu)
 {
 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
@@ -1271,7 +1368,6 @@ static struct subsys_interface cpufreq_interface = {
 	.remove_dev	= cpufreq_remove_dev,
 };
 
-
 /**
  * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
  *
@@ -1408,11 +1504,10 @@ int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
 }
 EXPORT_SYMBOL(cpufreq_register_notifier);
 
-
 /**
  *	cpufreq_unregister_notifier - unregister a driver with cpufreq
  *	@nb: notifier block to be unregistered
- *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
+ *	@list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
  *
  *	Remove a driver from the CPU frequency notifier list.
  *
@@ -1448,7 +1543,6 @@ EXPORT_SYMBOL(cpufreq_unregister_notifier);
  *                              GOVERNORS                            *
  *********************************************************************/
 
-
 int __cpufreq_driver_target(struct cpufreq_policy *policy,
 			    unsigned int target_freq,
 			    unsigned int relation)
@@ -1458,6 +1552,8 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
 
 	if (cpufreq_disabled())
 		return -ENODEV;
+	if (policy->transition_ongoing)
+		return -EBUSY;
 
 	/* Make sure that target_freq is within supported range */
 	if (target_freq > policy->max)
@@ -1484,10 +1580,6 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 {
 	int ret = -EINVAL;
 
-	policy = cpufreq_cpu_get(policy->cpu);
-	if (!policy)
-		goto no_policy;
-
 	if (unlikely(lock_policy_rwsem_write(policy->cpu)))
 		goto fail;
 
@@ -1496,30 +1588,19 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 	unlock_policy_rwsem_write(policy->cpu);
 
 fail:
-	cpufreq_cpu_put(policy);
-no_policy:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
 
 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
 {
-	int ret = 0;
-
 	if (cpufreq_disabled())
-		return ret;
+		return 0;
 
 	if (!cpufreq_driver->getavg)
 		return 0;
 
-	policy = cpufreq_cpu_get(policy->cpu);
-	if (!policy)
-		return -EINVAL;
-
-	ret = cpufreq_driver->getavg(policy, cpu);
-
-	cpufreq_cpu_put(policy);
-	return ret;
+	return cpufreq_driver->getavg(policy, cpu);
 }
 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
 
@@ -1562,6 +1643,21 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 
 	pr_debug("__cpufreq_governor for CPU %u, event %u\n",
 						policy->cpu, event);
+
+	mutex_lock(&cpufreq_governor_lock);
+	if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
+	    (policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
+		mutex_unlock(&cpufreq_governor_lock);
+		return -EBUSY;
+	}
+
+	if (event == CPUFREQ_GOV_STOP)
+		policy->governor_enabled = false;
+	else if (event == CPUFREQ_GOV_START)
+		policy->governor_enabled = true;
+
+	mutex_unlock(&cpufreq_governor_lock);
+
 	ret = policy->governor->governor(policy, event);
 
 	if (!ret) {
@@ -1569,6 +1665,14 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 			policy->governor->initialized++;
 		else if (event == CPUFREQ_GOV_POLICY_EXIT)
 			policy->governor->initialized--;
+	} else {
+		/* Restore original values */
+		mutex_lock(&cpufreq_governor_lock);
+		if (event == CPUFREQ_GOV_STOP)
+			policy->governor_enabled = true;
+		else if (event == CPUFREQ_GOV_START)
+			policy->governor_enabled = false;
+		mutex_unlock(&cpufreq_governor_lock);
 	}
 
 	/* we keep one module reference alive for
@@ -1581,7 +1685,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 	return ret;
 }
 
-
 int cpufreq_register_governor(struct cpufreq_governor *governor)
 {
 	int err;
@@ -1606,7 +1709,6 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)
 }
 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
 
-
 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
 {
 #ifdef CONFIG_HOTPLUG_CPU
@@ -1636,7 +1738,6 @@ void cpufreq_unregister_governor(struct cpufreq_governor *governor)
 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
 
 
-
 /*********************************************************************
  *                          POLICY INTERFACE                         *
  *********************************************************************/
@@ -1665,7 +1766,6 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
 }
 EXPORT_SYMBOL(cpufreq_get_policy);
 
-
 /*
  * data   : current policy.
  * policy : policy to be set.
@@ -1699,8 +1799,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
 			CPUFREQ_INCOMPATIBLE, policy);
 
-	/* verify the cpu speed can be set within this limit,
-	   which might be different to the first one */
+	/*
+	 * verify the cpu speed can be set within this limit, which might be
+	 * different to the first one
+	 */
 	ret = cpufreq_driver->verify(policy);
 	if (ret)
 		goto error_out;
@@ -1802,8 +1904,10 @@ int cpufreq_update_policy(unsigned int cpu)
 	policy.policy = data->user_policy.policy;
 	policy.governor = data->user_policy.governor;
 
-	/* BIOS might change freq behind our back
-	  -> ask driver for current freq and notify governors about a change */
+	/*
+	 * BIOS might change freq behind our back
+	 * -> ask driver for current freq and notify governors about a change
+	 */
 	if (cpufreq_driver->get) {
 		policy.cur = cpufreq_driver->get(cpu);
 		if (!data->cur) {
@@ -1852,7 +1956,7 @@ static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
 }
 
 static struct notifier_block __refdata cpufreq_cpu_notifier = {
-    .notifier_call = cpufreq_cpu_callback,
+	.notifier_call = cpufreq_cpu_callback,
 };
 
 /*********************************************************************
@@ -1864,7 +1968,7 @@ static struct notifier_block __refdata cpufreq_cpu_notifier = {
  * @driver_data: A struct cpufreq_driver containing the values#
  * submitted by the CPU Frequency driver.
  *
- *   Registers a CPU Frequency driver to this core code. This code
+ * Registers a CPU Frequency driver to this core code. This code
  * returns zero on success, -EBUSY when another driver got here first
  * (and isn't unregistered in the meantime).
  *
@@ -1931,11 +2035,10 @@ err_null_driver:
 }
 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
 
-
 /**
  * cpufreq_unregister_driver - unregister the current CPUFreq driver
  *
- *    Unregister the current CPUFreq driver. Only call this if you have
+ * Unregister the current CPUFreq driver. Only call this if you have
  * the right to do so, i.e. if you have succeeded in initialising before!
  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
  * currently not initialised.
@@ -1972,7 +2075,7 @@ static int __init cpufreq_core_init(void)
 		init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
 	}
 
-	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
+	cpufreq_global_kobject = kobject_create();
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);