Merge tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:
 "We have a few new features this time, including a new SFI-based
  cpufreq driver, a new devfreq driver for Tegra Activity Monitor, a new
  devfreq class for providing its governors with raw utilization data
  and a new ACPI driver for AMD SoCs.

  Still, the majority of changes here are reworks of existing code to
  make it more straightforward or to prepare it for implementing new
  features on top of it.  The primary example is the rework of ACPI
  resources handling from Jiang Liu, Thomas Gleixner and Lv Zheng with
  support for IOAPIC hotplug implemented on top of it, but there is
  quite a number of changes of this kind in the cpufreq core, ACPICA,
  ACPI EC driver, ACPI processor driver and the generic power domains
  core code too.

  The most active developer is Viresh Kumar with his cpufreq changes.

  Specifics:

   - Rework of the core ACPI resources parsing code to fix issues in it
     and make using resource offsets more convenient and consolidation
     of some resource-handing code in a couple of places that have grown
     analagous data structures and code to cover the the same gap in the
     core (Jiang Liu, Thomas Gleixner, Lv Zheng).

   - ACPI-based IOAPIC hotplug support on top of the resources handling
     rework (Jiang Liu, Yinghai Lu).

   - ACPICA update to upstream release 20150204 including an interrupt
     handling rework that allows drivers to install raw handlers for
     ACPI GPEs which then become entirely responsible for the given GPE
     and the ACPICA core code won't touch it (Lv Zheng, David E Box,
     Octavian Purdila).

   - ACPI EC driver rework to fix several concurrency issues and other
     problems related to events handling on top of the ACPICA's new
     support for raw GPE handlers (Lv Zheng).

   - New ACPI driver for AMD SoCs analogous to the LPSS (Low-Power
     Subsystem) driver for Intel chips (Ken Xue).

   - Two minor fixes of the ACPI LPSS driver (Heikki Krogerus, Jarkko
     Nikula).

   - Two new blacklist entries for machines (Samsung 730U3E/740U3E and
     510R) where the native backlight interface doesn't work correctly
     while the ACPI one does (Hans de Goede).

   - Rework of the ACPI processor driver's handling of idle states to
     make the code more straightforward and less bloated overall (Rafael
     J Wysocki).

   - Assorted minor fixes related to ACPI and SFI (Andreas Ruprecht,
     Andy Shevchenko, Hanjun Guo, Jan Beulich, Rafael J Wysocki, Yaowei
     Bai).

   - PCI core power management modification to avoid resuming (some)
     runtime-suspended devices during system suspend if they are in the
     right states already (Rafael J Wysocki).

   - New SFI-based cpufreq driver for Intel platforms using SFI
     (Srinidhi Kasagar).

   - cpufreq core fixes, cleanups and simplifications (Viresh Kumar,
     Doug Anderson, Wolfram Sang).

   - SkyLake CPU support and other updates for the intel_pstate driver
     (Kristen Carlson Accardi, Srinivas Pandruvada).

   - cpufreq-dt driver cleanup (Markus Elfring).

   - Init fix for the ARM big.LITTLE cpuidle driver (Sudeep Holla).

   - Generic power domains core code fixes and cleanups (Ulf Hansson).

   - Operating Performance Points (OPP) core code cleanups and kernel
     documentation update (Nishanth Menon).

   - New dabugfs interface to make the list of PM QoS constraints
     available to user space (Nishanth Menon).

   - New devfreq driver for Tegra Activity Monitor (Tomeu Vizoso).

   - New devfreq class (devfreq_event) to provide raw utilization data
     to devfreq governors (Chanwoo Choi).

   - Assorted minor fixes and cleanups related to power management
     (Andreas Ruprecht, Krzysztof Kozlowski, Rickard Strandqvist, Pavel
     Machek, Todd E Brandt, Wonhong Kwon).

   - turbostat updates (Len Brown) and cpupower Makefile improvement
     (Sriram Raghunathan)"

* tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (151 commits)
  tools/power turbostat: relax dependency on APERF_MSR
  tools/power turbostat: relax dependency on invariant TSC
  Merge branch 'pci/host-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci into acpi-resources
  tools/power turbostat: decode MSR_*_PERF_LIMIT_REASONS
  tools/power turbostat: relax dependency on root permission
  ACPI / video: Add disable_native_backlight quirk for Samsung 510R
  ACPI / PM: Remove unneeded nested #ifdef
  USB / PM: Remove unneeded #ifdef and associated dead code
  intel_pstate: provide option to only use intel_pstate with HWP
  ACPI / EC: Add GPE reference counting debugging messages
  ACPI / EC: Add query flushing support
  ACPI / EC: Refine command storm prevention support
  ACPI / EC: Add command flushing support.
  ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag
  ACPI: add AMD ACPI2Platform device support for x86 system
  ACPI / table: remove duplicate NULL check for the handler of acpi_table_parse()
  ACPI / EC: Update revision due to raw handler mode.
  ACPI / EC: Reduce ec_poll() by referencing the last register access timestamp.
  ACPI / EC: Fix several GPE handling issues by deploying ACPI_GPE_DISPATCH_RAW_HANDLER mode.
  ACPICA: Events: Enable APIs to allow interrupt/polling adaptive request based GPE handling model
  ...

4 files changed, 225 insertions, 148 deletions

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index b0f138806bbc..f32b802b98f4 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -19,8 +19,8 @@
  * @dev: Device to handle.
  *
  * If power.subsys_data is NULL, point it to a new object, otherwise increment
- * its reference counter.  Return 1 if a new object has been created, otherwise
- * return 0 or error code.
+ * its reference counter.  Return 0 if new object has been created or refcount
+ * increased, otherwise negative error code.
  */
 int dev_pm_get_subsys_data(struct device *dev)
 {
@@ -56,13 +56,11 @@ EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
  * @dev: Device to handle.
  *
  * If the reference counter of power.subsys_data is zero after dropping the
- * reference, power.subsys_data is removed.  Return 1 if that happens or 0
- * otherwise.
+ * reference, power.subsys_data is removed.
  */
-int dev_pm_put_subsys_data(struct device *dev)
+void dev_pm_put_subsys_data(struct device *dev)
 {
 	struct pm_subsys_data *psd;
-	int ret = 1;
 
 	spin_lock_irq(&dev->power.lock);
 
@@ -70,18 +68,14 @@ int dev_pm_put_subsys_data(struct device *dev)
 	if (!psd)
 		goto out;
 
-	if (--psd->refcount == 0) {
+	if (--psd->refcount == 0)
 		dev->power.subsys_data = NULL;
-	} else {
+	else
 		psd = NULL;
-		ret = 0;
-	}
 
  out:
 	spin_unlock_irq(&dev->power.lock);
 	kfree(psd);
-
-	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
 
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 0d8780c04a5e..ba4abbe4693c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -344,14 +344,7 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
 	struct device *dev;
 
 	gpd_data = container_of(nb, struct generic_pm_domain_data, nb);
-
-	mutex_lock(&gpd_data->lock);
 	dev = gpd_data->base.dev;
-	if (!dev) {
-		mutex_unlock(&gpd_data->lock);
-		return NOTIFY_DONE;
-	}
-	mutex_unlock(&gpd_data->lock);
 
 	for (;;) {
 		struct generic_pm_domain *genpd;
@@ -1384,25 +1377,66 @@ EXPORT_SYMBOL_GPL(pm_genpd_syscore_poweron);
 
 #endif /* CONFIG_PM_SLEEP */
 
-static struct generic_pm_domain_data *__pm_genpd_alloc_dev_data(struct device *dev)
+static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
+					struct generic_pm_domain *genpd,
+					struct gpd_timing_data *td)
 {
 	struct generic_pm_domain_data *gpd_data;
+	int ret;
+
+	ret = dev_pm_get_subsys_data(dev);
+	if (ret)
+		return ERR_PTR(ret);
 
 	gpd_data = kzalloc(sizeof(*gpd_data), GFP_KERNEL);
-	if (!gpd_data)
-		return NULL;
+	if (!gpd_data) {
+		ret = -ENOMEM;
+		goto err_put;
+	}
+
+	if (td)
+		gpd_data->td = *td;
 
-	mutex_init(&gpd_data->lock);
+	gpd_data->base.dev = dev;
+	gpd_data->need_restore = -1;
+	gpd_data->td.constraint_changed = true;
+	gpd_data->td.effective_constraint_ns = -1;
 	gpd_data->nb.notifier_call = genpd_dev_pm_qos_notifier;
-	dev_pm_qos_add_notifier(dev, &gpd_data->nb);
+
+	spin_lock_irq(&dev->power.lock);
+
+	if (dev->power.subsys_data->domain_data) {
+		ret = -EINVAL;
+		goto err_free;
+	}
+
+	dev->power.subsys_data->domain_data = &gpd_data->base;
+	dev->pm_domain = &genpd->domain;
+
+	spin_unlock_irq(&dev->power.lock);
+
 	return gpd_data;
+
+ err_free:
+	spin_unlock_irq(&dev->power.lock);
+	kfree(gpd_data);
+ err_put:
+	dev_pm_put_subsys_data(dev);
+	return ERR_PTR(ret);
 }
 
-static void __pm_genpd_free_dev_data(struct device *dev,
-				     struct generic_pm_domain_data *gpd_data)
+static void genpd_free_dev_data(struct device *dev,
+				struct generic_pm_domain_data *gpd_data)
 {
-	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
+	spin_lock_irq(&dev->power.lock);
+
+	dev->pm_domain = NULL;
+	dev->power.subsys_data->domain_data = NULL;
+
+	spin_unlock_irq(&dev->power.lock);
+
 	kfree(gpd_data);
+	dev_pm_put_subsys_data(dev);
 }
 
 /**
@@ -1414,8 +1448,7 @@ static void __pm_genpd_free_dev_data(struct device *dev,
 int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 			  struct gpd_timing_data *td)
 {
-	struct generic_pm_domain_data *gpd_data_new, *gpd_data = NULL;
-	struct pm_domain_data *pdd;
+	struct generic_pm_domain_data *gpd_data;
 	int ret = 0;
 
 	dev_dbg(dev, "%s()\n", __func__);
@@ -1423,9 +1456,9 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(dev))
 		return -EINVAL;
 
-	gpd_data_new = __pm_genpd_alloc_dev_data(dev);
-	if (!gpd_data_new)
-		return -ENOMEM;
+	gpd_data = genpd_alloc_dev_data(dev, genpd, td);
+	if (IS_ERR(gpd_data))
+		return PTR_ERR(gpd_data);
 
 	genpd_acquire_lock(genpd);
 
@@ -1434,50 +1467,22 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 		goto out;
 	}
 
-	list_for_each_entry(pdd, &genpd->dev_list, list_node)
-		if (pdd->dev == dev) {
-			ret = -EINVAL;
-			goto out;
-		}
-
-	ret = dev_pm_get_subsys_data(dev);
+	ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
 	if (ret)
 		goto out;
 
 	genpd->device_count++;
 	genpd->max_off_time_changed = true;
 
-	spin_lock_irq(&dev->power.lock);
-
-	dev->pm_domain = &genpd->domain;
-	if (dev->power.subsys_data->domain_data) {
-		gpd_data = to_gpd_data(dev->power.subsys_data->domain_data);
-	} else {
-		gpd_data = gpd_data_new;
-		dev->power.subsys_data->domain_data = &gpd_data->base;
-	}
-	gpd_data->refcount++;
-	if (td)
-		gpd_data->td = *td;
-
-	spin_unlock_irq(&dev->power.lock);
-
-	if (genpd->attach_dev)
-		genpd->attach_dev(genpd, dev);
-
-	mutex_lock(&gpd_data->lock);
-	gpd_data->base.dev = dev;
 	list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
-	gpd_data->need_restore = -1;
-	gpd_data->td.constraint_changed = true;
-	gpd_data->td.effective_constraint_ns = -1;
-	mutex_unlock(&gpd_data->lock);
 
  out:
 	genpd_release_lock(genpd);
 
-	if (gpd_data != gpd_data_new)
-		__pm_genpd_free_dev_data(dev, gpd_data_new);
+	if (ret)
+		genpd_free_dev_data(dev, gpd_data);
+	else
+		dev_pm_qos_add_notifier(dev, &gpd_data->nb);
 
 	return ret;
 }
@@ -1504,7 +1509,6 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 {
 	struct generic_pm_domain_data *gpd_data;
 	struct pm_domain_data *pdd;
-	bool remove = false;
 	int ret = 0;
 
 	dev_dbg(dev, "%s()\n", __func__);
@@ -1514,6 +1518,11 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	    ||  pd_to_genpd(dev->pm_domain) != genpd)
 		return -EINVAL;
 
+	/* The above validation also means we have existing domain_data. */
+	pdd = dev->power.subsys_data->domain_data;
+	gpd_data = to_gpd_data(pdd);
+	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
+
 	genpd_acquire_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
@@ -1527,58 +1536,22 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	if (genpd->detach_dev)
 		genpd->detach_dev(genpd, dev);
 
-	spin_lock_irq(&dev->power.lock);
-
-	dev->pm_domain = NULL;
-	pdd = dev->power.subsys_data->domain_data;
 	list_del_init(&pdd->list_node);
-	gpd_data = to_gpd_data(pdd);
-	if (--gpd_data->refcount == 0) {
-		dev->power.subsys_data->domain_data = NULL;
-		remove = true;
-	}
-
-	spin_unlock_irq(&dev->power.lock);
-
-	mutex_lock(&gpd_data->lock);
-	pdd->dev = NULL;
-	mutex_unlock(&gpd_data->lock);
 
 	genpd_release_lock(genpd);
 
-	dev_pm_put_subsys_data(dev);
-	if (remove)
-		__pm_genpd_free_dev_data(dev, gpd_data);
+	genpd_free_dev_data(dev, gpd_data);
 
 	return 0;
 
  out:
 	genpd_release_lock(genpd);
+	dev_pm_qos_add_notifier(dev, &gpd_data->nb);
 
 	return ret;
 }
 
 /**
- * pm_genpd_dev_need_restore - Set/unset the device's "need restore" flag.
- * @dev: Device to set/unset the flag for.
- * @val: The new value of the device's "need restore" flag.
- */
-void pm_genpd_dev_need_restore(struct device *dev, bool val)
-{
-	struct pm_subsys_data *psd;
-	unsigned long flags;
-
-	spin_lock_irqsave(&dev->power.lock, flags);
-
-	psd = dev_to_psd(dev);
-	if (psd && psd->domain_data)
-		to_gpd_data(psd->domain_data)->need_restore = val ? 1 : 0;
-
-	spin_unlock_irqrestore(&dev->power.lock, flags);
-}
-EXPORT_SYMBOL_GPL(pm_genpd_dev_need_restore);
-
-/**
  * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain.
  * @genpd: Master PM domain to add the subdomain to.
  * @subdomain: Subdomain to be added.
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 106c69359306..15bf29974c31 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -117,20 +117,20 @@ do {									\
 } while (0)
 
 /**
- * find_device_opp() - find device_opp struct using device pointer
+ * _find_device_opp() - find device_opp struct using device pointer
  * @dev:	device pointer used to lookup device OPPs
  *
  * Search list of device OPPs for one containing matching device. Does a RCU
  * reader operation to grab the pointer needed.
  *
- * Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or
+ * Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
  * -EINVAL based on type of error.
  *
  * Locking: This function must be called under rcu_read_lock(). device_opp
  * is a RCU protected pointer. This means that device_opp is valid as long
  * as we are under RCU lock.
  */
-static struct device_opp *find_device_opp(struct device *dev)
+static struct device_opp *_find_device_opp(struct device *dev)
 {
 	struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV);
 
@@ -153,7 +153,7 @@ static struct device_opp *find_device_opp(struct device *dev)
  * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
  * @opp:	opp for which voltage has to be returned for
  *
- * Return voltage in micro volt corresponding to the opp, else
+ * Return: voltage in micro volt corresponding to the opp, else
  * return 0
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
@@ -169,6 +169,8 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	struct dev_pm_opp *tmp_opp;
 	unsigned long v = 0;
 
+	opp_rcu_lockdep_assert();
+
 	tmp_opp = rcu_dereference(opp);
 	if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
 		pr_err("%s: Invalid parameters\n", __func__);
@@ -183,7 +185,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
  * dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
  * @opp:	opp for which frequency has to be returned for
  *
- * Return frequency in hertz corresponding to the opp, else
+ * Return: frequency in hertz corresponding to the opp, else
  * return 0
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
@@ -199,6 +201,8 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 	struct dev_pm_opp *tmp_opp;
 	unsigned long f = 0;
 
+	opp_rcu_lockdep_assert();
+
 	tmp_opp = rcu_dereference(opp);
 	if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
 		pr_err("%s: Invalid parameters\n", __func__);
@@ -213,7 +217,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
  * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
  * @dev:	device for which we do this operation
  *
- * This function returns the number of available opps if there are any,
+ * Return: This function returns the number of available opps if there are any,
  * else returns 0 if none or the corresponding error value.
  *
  * Locking: This function takes rcu_read_lock().
@@ -226,7 +230,7 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 
 	rcu_read_lock();
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		count = PTR_ERR(dev_opp);
 		dev_err(dev, "%s: device OPP not found (%d)\n",
@@ -251,9 +255,9 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
  * @freq:		frequency to search for
  * @available:		true/false - match for available opp
  *
- * Searches for exact match in the opp list and returns pointer to the matching
- * opp if found, else returns ERR_PTR in case of error and should be handled
- * using IS_ERR. Error return values can be:
+ * Return: Searches for exact match in the opp list and returns pointer to the
+ * matching opp if found, else returns ERR_PTR in case of error and should
+ * be handled using IS_ERR. Error return values can be:
  * EINVAL:	for bad pointer
  * ERANGE:	no match found for search
  * ENODEV:	if device not found in list of registered devices
@@ -280,7 +284,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 
 	opp_rcu_lockdep_assert();
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int r = PTR_ERR(dev_opp);
 		dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
@@ -307,7 +311,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
  * Search for the matching ceil *available* OPP from a starting freq
  * for a device.
  *
- * Returns matching *opp and refreshes *freq accordingly, else returns
+ * Return: matching *opp and refreshes *freq accordingly, else returns
  * ERR_PTR in case of error and should be handled using IS_ERR. Error return
  * values can be:
  * EINVAL:	for bad pointer
@@ -333,7 +337,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp))
 		return ERR_CAST(dev_opp);
 
@@ -357,7 +361,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
  * Search for the matching floor *available* OPP from a starting freq
  * for a device.
  *
- * Returns matching *opp and refreshes *freq accordingly, else returns
+ * Return: matching *opp and refreshes *freq accordingly, else returns
  * ERR_PTR in case of error and should be handled using IS_ERR. Error return
  * values can be:
  * EINVAL:	for bad pointer
@@ -383,7 +387,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp))
 		return ERR_CAST(dev_opp);
 
@@ -403,7 +407,16 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
 
-static struct device_opp *add_device_opp(struct device *dev)
+/**
+ * _add_device_opp() - Allocate a new device OPP table
+ * @dev:	device for which we do this operation
+ *
+ * New device node which uses OPPs - used when multiple devices with OPP tables
+ * are maintained.
+ *
+ * Return: valid device_opp pointer if success, else NULL.
+ */
+static struct device_opp *_add_device_opp(struct device *dev)
 {
 	struct device_opp *dev_opp;
 
@@ -424,8 +437,35 @@ static struct device_opp *add_device_opp(struct device *dev)
 	return dev_opp;
 }
 
-static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq,
-				  unsigned long u_volt, bool dynamic)
+/**
+ * _opp_add_dynamic() - Allocate a dynamic OPP.
+ * @dev:	device for which we do this operation
+ * @freq:	Frequency in Hz for this OPP
+ * @u_volt:	Voltage in uVolts for this OPP
+ * @dynamic:	Dynamically added OPPs.
+ *
+ * This function adds an opp definition to the opp list and returns status.
+ * The opp is made available by default and it can be controlled using
+ * dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
+ *
+ * NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
+ * freed by of_free_opp_table.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ */
+static int _opp_add_dynamic(struct device *dev, unsigned long freq,
+			    long u_volt, bool dynamic)
 {
 	struct device_opp *dev_opp = NULL;
 	struct dev_pm_opp *opp, *new_opp;
@@ -449,9 +489,9 @@ static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq,
 	new_opp->dynamic = dynamic;
 
 	/* Check for existing list for 'dev' */
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
-		dev_opp = add_device_opp(dev);
+		dev_opp = _add_device_opp(dev);
 		if (!dev_opp) {
 			ret = -ENOMEM;
 			goto free_opp;
@@ -519,34 +559,53 @@ free_opp:
  * mutex cannot be locked.
  *
  * Return:
- * 0:		On success OR
+ * 0		On success OR
  *		Duplicate OPPs (both freq and volt are same) and opp->available
- * -EEXIST:	Freq are same and volt are different OR
+ * -EEXIST	Freq are same and volt are different OR
  *		Duplicate OPPs (both freq and volt are same) and !opp->available
- * -ENOMEM:	Memory allocation failure
+ * -ENOMEM	Memory allocation failure
  */
 int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
 {
-	return dev_pm_opp_add_dynamic(dev, freq, u_volt, true);
+	return _opp_add_dynamic(dev, freq, u_volt, true);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_add);
 
-static void kfree_opp_rcu(struct rcu_head *head)
+/**
+ * _kfree_opp_rcu() - Free OPP RCU handler
+ * @head:	RCU head
+ */
+static void _kfree_opp_rcu(struct rcu_head *head)
 {
 	struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
 
 	kfree_rcu(opp, rcu_head);
 }
 
-static void kfree_device_rcu(struct rcu_head *head)
+/**
+ * _kfree_device_rcu() - Free device_opp RCU handler
+ * @head:	RCU head
+ */
+static void _kfree_device_rcu(struct rcu_head *head)
 {
 	struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
 
 	kfree_rcu(device_opp, rcu_head);
 }
 
-static void __dev_pm_opp_remove(struct device_opp *dev_opp,
-				struct dev_pm_opp *opp)
+/**
+ * _opp_remove()  - Remove an OPP from a table definition
+ * @dev_opp:	points back to the device_opp struct this opp belongs to
+ * @opp:	pointer to the OPP to remove
+ *
+ * This function removes an opp definition from the opp list.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * It is assumed that the caller holds required mutex for an RCU updater
+ * strategy.
+ */
+static void _opp_remove(struct device_opp *dev_opp,
+			struct dev_pm_opp *opp)
 {
 	/*
 	 * Notify the changes in the availability of the operable
@@ -554,12 +613,12 @@ static void __dev_pm_opp_remove(struct device_opp *dev_opp,
 	 */
 	srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
 	list_del_rcu(&opp->node);
-	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu);
+	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
 
 	if (list_empty(&dev_opp->opp_list)) {
 		list_del_rcu(&dev_opp->node);
 		call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head,
-			  kfree_device_rcu);
+			  _kfree_device_rcu);
 	}
 }
 
@@ -569,6 +628,12 @@ static void __dev_pm_opp_remove(struct device_opp *dev_opp,
  * @freq:	OPP to remove with matching 'freq'
  *
  * This function removes an opp from the opp list.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
  */
 void dev_pm_opp_remove(struct device *dev, unsigned long freq)
 {
@@ -579,7 +644,7 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
 	/* Hold our list modification lock here */
 	mutex_lock(&dev_opp_list_lock);
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp))
 		goto unlock;
 
@@ -596,14 +661,14 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
 		goto unlock;
 	}
 
-	__dev_pm_opp_remove(dev_opp, opp);
+	_opp_remove(dev_opp, opp);
 unlock:
 	mutex_unlock(&dev_opp_list_lock);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
 
 /**
- * opp_set_availability() - helper to set the availability of an opp
+ * _opp_set_availability() - helper to set the availability of an opp
  * @dev:		device for which we do this operation
  * @freq:		OPP frequency to modify availability
  * @availability_req:	availability status requested for this opp
@@ -611,7 +676,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
  * Set the availability of an OPP with an RCU operation, opp_{enable,disable}
  * share a common logic which is isolated here.
  *
- * Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
  * copy operation, returns 0 if no modifcation was done OR modification was
  * successful.
  *
@@ -621,8 +686,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
  * that this function is *NOT* called under RCU protection or in contexts where
  * mutex locking or synchronize_rcu() blocking calls cannot be used.
  */
-static int opp_set_availability(struct device *dev, unsigned long freq,
-		bool availability_req)
+static int _opp_set_availability(struct device *dev, unsigned long freq,
+				 bool availability_req)
 {
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
@@ -638,7 +703,7 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
 	mutex_lock(&dev_opp_list_lock);
 
 	/* Find the device_opp */
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		r = PTR_ERR(dev_opp);
 		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
@@ -668,7 +733,7 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
 
 	list_replace_rcu(&opp->node, &new_opp->node);
 	mutex_unlock(&dev_opp_list_lock);
-	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu);
+	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
 
 	/* Notify the change of the OPP availability */
 	if (availability_req)
@@ -700,10 +765,14 @@ unlock:
  * integrity of the internal data structures. Callers should ensure that
  * this function is *NOT* called under RCU protection or in contexts where
  * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modifcation was done OR modification was
+ * successful.
  */
 int dev_pm_opp_enable(struct device *dev, unsigned long freq)
 {
-	return opp_set_availability(dev, freq, true);
+	return _opp_set_availability(dev, freq, true);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
 
@@ -722,26 +791,41 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
  * integrity of the internal data structures. Callers should ensure that
  * this function is *NOT* called under RCU protection or in contexts where
  * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modifcation was done OR modification was
+ * successful.
  */
 int dev_pm_opp_disable(struct device *dev, unsigned long freq)
 {
-	return opp_set_availability(dev, freq, false);
+	return _opp_set_availability(dev, freq, false);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
 
 /**
  * dev_pm_opp_get_notifier() - find notifier_head of the device with opp
  * @dev:	device pointer used to lookup device OPPs.
+ *
+ * Return: pointer to  notifier head if found, otherwise -ENODEV or
+ * -EINVAL based on type of error casted as pointer. value must be checked
+ *  with IS_ERR to determine valid pointer or error result.
+ *
+ * Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
  */
 struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
 {
-	struct device_opp *dev_opp = find_device_opp(dev);
+	struct device_opp *dev_opp = _find_device_opp(dev);
 
 	if (IS_ERR(dev_opp))
 		return ERR_CAST(dev_opp); /* matching type */
 
 	return &dev_opp->srcu_head;
 }
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
 
 #ifdef CONFIG_OF
 /**
@@ -749,6 +833,22 @@ struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
  * @dev:	device pointer used to lookup device OPPs.
  *
  * Register the initial OPP table with the OPP library for given device.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ * -ENODEV	when 'operating-points' property is not found or is invalid data
+ *		in device node.
+ * -ENODATA	when empty 'operating-points' property is found
  */
 int of_init_opp_table(struct device *dev)
 {
@@ -777,7 +877,7 @@ int of_init_opp_table(struct device *dev)
 		unsigned long freq = be32_to_cpup(val++) * 1000;
 		unsigned long volt = be32_to_cpup(val++);
 
-		if (dev_pm_opp_add_dynamic(dev, freq, volt, false))
+		if (_opp_add_dynamic(dev, freq, volt, false))
 			dev_warn(dev, "%s: Failed to add OPP %ld\n",
 				 __func__, freq);
 		nr -= 2;
@@ -792,6 +892,12 @@ EXPORT_SYMBOL_GPL(of_init_opp_table);
  * @dev:	device pointer used to lookup device OPPs.
  *
  * Free OPPs created using static entries present in DT.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
  */
 void of_free_opp_table(struct device *dev)
 {
@@ -799,7 +905,7 @@ void of_free_opp_table(struct device *dev)
 	struct dev_pm_opp *opp, *tmp;
 
 	/* Check for existing list for 'dev' */
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int error = PTR_ERR(dev_opp);
 		if (error != -ENODEV)
@@ -816,7 +922,7 @@ void of_free_opp_table(struct device *dev)
 	/* Free static OPPs */
 	list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) {
 		if (!opp->dynamic)
-			__dev_pm_opp_remove(dev_opp, opp);
+			_opp_remove(dev_opp, opp);
 	}
 
 	mutex_unlock(&dev_opp_list_lock);
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index a8fe4c1a8d07..e56d538d039e 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -64,6 +64,8 @@ enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
 	struct pm_qos_flags *pqf;
 	s32 val;
 
+	lockdep_assert_held(&dev->power.lock);
+
 	if (IS_ERR_OR_NULL(qos))
 		return PM_QOS_FLAGS_UNDEFINED;
 
@@ -104,6 +106,8 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
  */
 s32 __dev_pm_qos_read_value(struct device *dev)
 {
+	lockdep_assert_held(&dev->power.lock);
+
 	return IS_ERR_OR_NULL(dev->power.qos) ?
 		0 : pm_qos_read_value(&dev->power.qos->resume_latency);
 }