From b02f6695f7601c4f8442b9cf4636802e7fa8d550 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 11 Feb 2014 00:35:23 +0100
Subject: PM / QoS: Rename device resume latency QoS items

Rename symbols, variables, functions and structure fields related do
the resume latency device PM QoS type so that it is clear where they
belong (in particular, to avoid confusion with the latency tolerance
device PM QoS type introduced by a subsequent changeset).

Update the PM QoS documentation to better reflect its current state.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/power.h  |  4 ++--
 drivers/base/power/qos.c    | 55 ++++++++++++++++++++++-----------------------
 drivers/base/power/sysfs.c  | 32 +++++++++++++-------------
 drivers/mtd/nand/sh_flctl.c |  2 +-
 4 files changed, 47 insertions(+), 46 deletions(-)

(limited to 'drivers')

diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index cfc3226ec492..a21223d95926 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -89,8 +89,8 @@ extern void dpm_sysfs_remove(struct device *dev);
 extern void rpm_sysfs_remove(struct device *dev);
 extern int wakeup_sysfs_add(struct device *dev);
 extern void wakeup_sysfs_remove(struct device *dev);
-extern int pm_qos_sysfs_add_latency(struct device *dev);
-extern void pm_qos_sysfs_remove_latency(struct device *dev);
+extern int pm_qos_sysfs_add_resume_latency(struct device *dev);
+extern void pm_qos_sysfs_remove_resume_latency(struct device *dev);
 extern int pm_qos_sysfs_add_flags(struct device *dev);
 extern void pm_qos_sysfs_remove_flags(struct device *dev);
 
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 5c1361a9e5dd..67c0f4219b02 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -105,7 +105,7 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
 s32 __dev_pm_qos_read_value(struct device *dev)
 {
 	return IS_ERR_OR_NULL(dev->power.qos) ?
-		0 : pm_qos_read_value(&dev->power.qos->latency);
+		0 : pm_qos_read_value(&dev->power.qos->resume_latency);
 }
 
 /**
@@ -141,11 +141,11 @@ static int apply_constraint(struct dev_pm_qos_request *req,
 	int ret;
 
 	switch(req->type) {
-	case DEV_PM_QOS_LATENCY:
-		ret = pm_qos_update_target(&qos->latency, &req->data.pnode,
-					   action, value);
+	case DEV_PM_QOS_RESUME_LATENCY:
+		ret = pm_qos_update_target(&qos->resume_latency,
+					   &req->data.pnode, action, value);
 		if (ret) {
-			value = pm_qos_read_value(&qos->latency);
+			value = pm_qos_read_value(&qos->resume_latency);
 			blocking_notifier_call_chain(&dev_pm_notifiers,
 						     (unsigned long)value,
 						     req);
@@ -186,10 +186,10 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
 	}
 	BLOCKING_INIT_NOTIFIER_HEAD(n);
 
-	c = &qos->latency;
+	c = &qos->resume_latency;
 	plist_head_init(&c->list);
-	c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
-	c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+	c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
+	c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
 	c->type = PM_QOS_MIN;
 	c->notifiers = n;
 
@@ -224,7 +224,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 	 * If the device's PM QoS resume latency limit or PM QoS flags have been
 	 * exposed to user space, they have to be hidden at this point.
 	 */
-	pm_qos_sysfs_remove_latency(dev);
+	pm_qos_sysfs_remove_resume_latency(dev);
 	pm_qos_sysfs_remove_flags(dev);
 
 	mutex_lock(&dev_pm_qos_mtx);
@@ -237,7 +237,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 		goto out;
 
 	/* Flush the constraints lists for the device. */
-	c = &qos->latency;
+	c = &qos->resume_latency;
 	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
 		/*
 		 * Update constraints list and call the notification
@@ -341,7 +341,7 @@ static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
 		return -ENODEV;
 
 	switch(req->type) {
-	case DEV_PM_QOS_LATENCY:
+	case DEV_PM_QOS_RESUME_LATENCY:
 		curr_value = req->data.pnode.prio;
 		break;
 	case DEV_PM_QOS_FLAGS:
@@ -460,8 +460,8 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
 		ret = dev_pm_qos_constraints_allocate(dev);
 
 	if (!ret)
-		ret = blocking_notifier_chain_register(
-				dev->power.qos->latency.notifiers, notifier);
+		ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
+						       notifier);
 
 	mutex_unlock(&dev_pm_qos_mtx);
 	return ret;
@@ -487,9 +487,8 @@ int dev_pm_qos_remove_notifier(struct device *dev,
 
 	/* Silently return if the constraints object is not present. */
 	if (!IS_ERR_OR_NULL(dev->power.qos))
-		retval = blocking_notifier_chain_unregister(
-				dev->power.qos->latency.notifiers,
-				notifier);
+		retval = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
+							    notifier);
 
 	mutex_unlock(&dev_pm_qos_mtx);
 	return retval;
@@ -543,7 +542,7 @@ int dev_pm_qos_add_ancestor_request(struct device *dev,
 
 	if (ancestor)
 		ret = dev_pm_qos_add_request(ancestor, req,
-					     DEV_PM_QOS_LATENCY, value);
+					     DEV_PM_QOS_RESUME_LATENCY, value);
 
 	if (ret < 0)
 		req->dev = NULL;
@@ -559,9 +558,9 @@ static void __dev_pm_qos_drop_user_request(struct device *dev,
 	struct dev_pm_qos_request *req = NULL;
 
 	switch(type) {
-	case DEV_PM_QOS_LATENCY:
-		req = dev->power.qos->latency_req;
-		dev->power.qos->latency_req = NULL;
+	case DEV_PM_QOS_RESUME_LATENCY:
+		req = dev->power.qos->resume_latency_req;
+		dev->power.qos->resume_latency_req = NULL;
 		break;
 	case DEV_PM_QOS_FLAGS:
 		req = dev->power.qos->flags_req;
@@ -597,7 +596,7 @@ int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
 	if (!req)
 		return -ENOMEM;
 
-	ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY, value);
+	ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
 	if (ret < 0) {
 		kfree(req);
 		return ret;
@@ -609,7 +608,7 @@ int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
 
 	if (IS_ERR_OR_NULL(dev->power.qos))
 		ret = -ENODEV;
-	else if (dev->power.qos->latency_req)
+	else if (dev->power.qos->resume_latency_req)
 		ret = -EEXIST;
 
 	if (ret < 0) {
@@ -618,13 +617,13 @@ int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
 		mutex_unlock(&dev_pm_qos_mtx);
 		goto out;
 	}
-	dev->power.qos->latency_req = req;
+	dev->power.qos->resume_latency_req = req;
 
 	mutex_unlock(&dev_pm_qos_mtx);
 
-	ret = pm_qos_sysfs_add_latency(dev);
+	ret = pm_qos_sysfs_add_resume_latency(dev);
 	if (ret)
-		dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
+		dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
 
  out:
 	mutex_unlock(&dev_pm_qos_sysfs_mtx);
@@ -634,8 +633,8 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
 
 static void __dev_pm_qos_hide_latency_limit(struct device *dev)
 {
-	if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->latency_req)
-		__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
+	if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
+		__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
 }
 
 /**
@@ -646,7 +645,7 @@ void dev_pm_qos_hide_latency_limit(struct device *dev)
 {
 	mutex_lock(&dev_pm_qos_sysfs_mtx);
 
-	pm_qos_sysfs_remove_latency(dev);
+	pm_qos_sysfs_remove_resume_latency(dev);
 
 	mutex_lock(&dev_pm_qos_mtx);
 	__dev_pm_qos_hide_latency_limit(dev);
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 03e089ade5ce..4e24955aac8a 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -218,15 +218,16 @@ static ssize_t autosuspend_delay_ms_store(struct device *dev,
 static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
 		autosuspend_delay_ms_store);
 
-static ssize_t pm_qos_latency_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
+static ssize_t pm_qos_resume_latency_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
 {
-	return sprintf(buf, "%d\n", dev_pm_qos_requested_latency(dev));
+	return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
 }
 
-static ssize_t pm_qos_latency_store(struct device *dev,
-				    struct device_attribute *attr,
-				    const char *buf, size_t n)
+static ssize_t pm_qos_resume_latency_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t n)
 {
 	s32 value;
 	int ret;
@@ -237,12 +238,13 @@ static ssize_t pm_qos_latency_store(struct device *dev,
 	if (value < 0)
 		return -EINVAL;
 
-	ret = dev_pm_qos_update_request(dev->power.qos->latency_req, value);
+	ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
+					value);
 	return ret < 0 ? ret : n;
 }
 
 static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
-		   pm_qos_latency_show, pm_qos_latency_store);
+		   pm_qos_resume_latency_show, pm_qos_resume_latency_store);
 
 static ssize_t pm_qos_no_power_off_show(struct device *dev,
 					struct device_attribute *attr,
@@ -618,15 +620,15 @@ static struct attribute_group pm_runtime_attr_group = {
 	.attrs	= runtime_attrs,
 };
 
-static struct attribute *pm_qos_latency_attrs[] = {
+static struct attribute *pm_qos_resume_latency_attrs[] = {
 #ifdef CONFIG_PM_RUNTIME
 	&dev_attr_pm_qos_resume_latency_us.attr,
 #endif /* CONFIG_PM_RUNTIME */
 	NULL,
 };
-static struct attribute_group pm_qos_latency_attr_group = {
+static struct attribute_group pm_qos_resume_latency_attr_group = {
 	.name	= power_group_name,
-	.attrs	= pm_qos_latency_attrs,
+	.attrs	= pm_qos_resume_latency_attrs,
 };
 
 static struct attribute *pm_qos_flags_attrs[] = {
@@ -681,14 +683,14 @@ void wakeup_sysfs_remove(struct device *dev)
 	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
 }
 
-int pm_qos_sysfs_add_latency(struct device *dev)
+int pm_qos_sysfs_add_resume_latency(struct device *dev)
 {
-	return sysfs_merge_group(&dev->kobj, &pm_qos_latency_attr_group);
+	return sysfs_merge_group(&dev->kobj, &pm_qos_resume_latency_attr_group);
 }
 
-void pm_qos_sysfs_remove_latency(struct device *dev)
+void pm_qos_sysfs_remove_resume_latency(struct device *dev)
 {
-	sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_attr_group);
+	sysfs_unmerge_group(&dev->kobj, &pm_qos_resume_latency_attr_group);
 }
 
 int pm_qos_sysfs_add_flags(struct device *dev)
diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
index d72783dd7b96..c0670237e7a2 100644
--- a/drivers/mtd/nand/sh_flctl.c
+++ b/drivers/mtd/nand/sh_flctl.c
@@ -897,7 +897,7 @@ static void flctl_select_chip(struct mtd_info *mtd, int chipnr)
 		if (!flctl->qos_request) {
 			ret = dev_pm_qos_add_request(&flctl->pdev->dev,
 							&flctl->pm_qos,
-							DEV_PM_QOS_LATENCY,
+							DEV_PM_QOS_RESUME_LATENCY,
 							100);
 			if (ret < 0)
 				dev_err(&flctl->pdev->dev,
-- 
cgit v1.2.3


From 327adaedf2218b0e318eb393aa79cf2be64c199f Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 11 Feb 2014 00:35:29 +0100
Subject: PM / QoS: Add no_constraints_value field to struct pm_qos_constraints

Add a new field, no_constraints_value, to struct pm_qos_constraints
representing a list of PM QoS constraint requests to be returned by
pm_qos_get_value() when that list of requests is empty.

That field will be equal to default_value for all of the existing
global PM QoS classes and for the resume latency device PM QoS type,
but it will be different from default_value for the new latency
tolerance device PM QoS type introduced by the next changeset.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/qos.c | 1 +
 include/linux/pm_qos.h   | 1 +
 kernel/power/qos.c       | 5 ++++-
 3 files changed, 6 insertions(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 67c0f4219b02..c754e55f9dcb 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -190,6 +190,7 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
 	plist_head_init(&c->list);
 	c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
 	c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
+	c->no_constraint_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
 	c->type = PM_QOS_MIN;
 	c->notifiers = n;
 
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 88a3680ae74c..2d8ce50877d8 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -77,6 +77,7 @@ struct pm_qos_constraints {
 	struct plist_head list;
 	s32 target_value;	/* Do not change to 64 bit */
 	s32 default_value;
+	s32 no_constraint_value;
 	enum pm_qos_type type;
 	struct blocking_notifier_head *notifiers;
 };
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 8dff9b48075a..e23ae38e647f 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -66,6 +66,7 @@ static struct pm_qos_constraints cpu_dma_constraints = {
 	.list = PLIST_HEAD_INIT(cpu_dma_constraints.list),
 	.target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.type = PM_QOS_MIN,
 	.notifiers = &cpu_dma_lat_notifier,
 };
@@ -79,6 +80,7 @@ static struct pm_qos_constraints network_lat_constraints = {
 	.list = PLIST_HEAD_INIT(network_lat_constraints.list),
 	.target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
 	.default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
 	.type = PM_QOS_MIN,
 	.notifiers = &network_lat_notifier,
 };
@@ -93,6 +95,7 @@ static struct pm_qos_constraints network_tput_constraints = {
 	.list = PLIST_HEAD_INIT(network_tput_constraints.list),
 	.target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
 	.default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
 	.type = PM_QOS_MAX,
 	.notifiers = &network_throughput_notifier,
 };
@@ -128,7 +131,7 @@ static const struct file_operations pm_qos_power_fops = {
 static inline int pm_qos_get_value(struct pm_qos_constraints *c)
 {
 	if (plist_head_empty(&c->list))
-		return c->default_value;
+		return c->no_constraint_value;
 
 	switch (c->type) {
 	case PM_QOS_MIN:
-- 
cgit v1.2.3


From 2d984ad132a87ca2112f81f21039493176a8bca0 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 11 Feb 2014 00:35:38 +0100
Subject: PM / QoS: Introcuce latency tolerance device PM QoS type

Add a new latency tolerance device PM QoS type to be use for
specifying active state (RPM_ACTIVE) memory access (DMA) latency
tolerance requirements for devices.  It may be used to prevent
hardware from choosing overly aggressive energy-saving operation
modes (causing too much latency to appear) for the whole platform.

This feature reqiures hardware support, so it only will be
available for devices having a new .set_latency_tolerance()
callback in struct dev_pm_info populated, in which case the
routine pointed to by it should implement whatever is necessary
to transfer the effective requirement value to the hardware.

Whenever the effective latency tolerance changes for the device,
its .set_latency_tolerance() callback will be executed and the
effective value will be passed to it.  If that value is negative,
which means that the list of latency tolerance requirements for
the device is empty, the callback is expected to switch the
underlying hardware latency tolerance control mechanism to an
autonomous mode if available.  If that value is PM_QOS_LATENCY_ANY,
in turn, and the hardware supports a special "no requirement"
setting, the callback is expected to use it.  That allows software
to prevent the hardware from automatically updating the device's
latency tolerance in response to its power state changes (e.g. during
transitions from D3cold to D0), which generally may be done in the
autonomous latency tolerance control mode.

If .set_latency_tolerance() is present for the device, a new
pm_qos_latency_tolerance_us attribute will be present in the
devivce's power directory in sysfs.  Then, user space can use
that attribute to specify its latency tolerance requirement for
the device, if any.  Writing "any" to it means "no requirement, but
do not let the hardware control latency tolerance" and writing
"auto" to it allows the hardware to be switched to the autonomous
mode if there are no other requirements from the kernel side in the
device's list.

This changeset includes a fix from Mika Westerberg.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 Documentation/ABI/testing/sysfs-devices-power |  27 ++++-
 Documentation/power/pm_qos_interface.txt      |  59 +++++++++--
 drivers/base/power/qos.c                      | 144 ++++++++++++++++++++++----
 drivers/base/power/sysfs.c                    |  65 ++++++++++--
 include/linux/pm.h                            |   1 +
 include/linux/pm_qos.h                        |  12 +++
 kernel/power/qos.c                            |  13 ++-
 7 files changed, 277 insertions(+), 44 deletions(-)

(limited to 'drivers')

diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power
index efe449bdf811..7dbf96b724ed 100644
--- a/Documentation/ABI/testing/sysfs-devices-power
+++ b/Documentation/ABI/testing/sysfs-devices-power
@@ -187,7 +187,7 @@ Description:
 		Not all drivers support this attribute.  If it isn't supported,
 		attempts to read or write it will yield I/O errors.
 
-What:		/sys/devices/.../power/pm_qos_latency_us
+What:		/sys/devices/.../power/pm_qos_resume_latency_us
 Date:		March 2012
 Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
 Description:
@@ -205,6 +205,31 @@ Description:
 		This attribute has no effect on system-wide suspend/resume and
 		hibernation.
 
+What:		/sys/devices/.../power/pm_qos_latency_tolerance_us
+Date:		January 2014
+Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
+Description:
+		The /sys/devices/.../power/pm_qos_latency_tolerance_us attribute
+		contains the PM QoS active state latency tolerance limit for the
+		given device in microseconds.  That is the maximum memory access
+		latency the device can suffer without any visible adverse
+		effects on user space functionality.  If that value is the
+		string "any", the latency does not matter to user space at all,
+		but hardware should not be allowed to set the latency tolerance
+		for the device automatically.
+
+		Reading "auto" from this file means that the maximum memory
+		access latency for the device may be determined automatically
+		by the hardware as needed.  Writing "auto" to it allows the
+		hardware to be switched to this mode if there are no other
+		latency tolerance requirements from the kernel side.
+
+		This attribute is only present if the feature controlled by it
+		is supported by the hardware.
+
+		This attribute has no effect on runtime suspend and resume of
+		devices and on system-wide suspend/resume and hibernation.
+
 What:		/sys/devices/.../power/pm_qos_no_power_off
 Date:		September 2012
 Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt
index 22cb8f51182a..ed743bbad87c 100644
--- a/Documentation/power/pm_qos_interface.txt
+++ b/Documentation/power/pm_qos_interface.txt
@@ -88,17 +88,19 @@ node.
 
 2. PM QoS per-device latency and flags framework
 
-For each device, there are two lists of PM QoS requests. One is maintained
-along with the aggregated target of resume latency value and the other is for
-PM QoS flags. Values are updated in response to changes of the request list.
+For each device, there are three lists of PM QoS requests. Two of them are
+maintained along with the aggregated targets of resume latency and active
+state latency tolerance (in microseconds) and the third one is for PM QoS flags.
+Values are updated in response to changes of the request list.
 
-Target resume latency value is simply the minimum of the request values held in
-the parameter list elements.  The PM QoS flags aggregate value is a gather
-(bitwise OR) of all list elements' values.  Two device PM QoS flags are defined
-currently: PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP.
+The target values of resume latency and active state latency tolerance are
+simply the minimum of the request values held in the parameter list elements.
+The PM QoS flags aggregate value is a gather (bitwise OR) of all list elements'
+values.  Two device PM QoS flags are defined currently: PM_QOS_FLAG_NO_POWER_OFF
+and PM_QOS_FLAG_REMOTE_WAKEUP.
 
-Note: the aggregated target value is implemented in such a way that reading the
-aggregated value does not require any locking mechanism.
+Note: The aggregated target values are implemented in such a way that reading
+the aggregated value does not require any locking mechanism.
 
 
 From kernel mode the use of this interface is the following:
@@ -177,3 +179,42 @@ The callback is called when the aggregated value for any device is changed
 int dev_pm_qos_remove_global_notifier(notifier):
 Removes the notification callback function from the global notification tree
 of the framework.
+
+
+Active state latency tolerance
+
+This device PM QoS type is used to support systems in which hardware may switch
+to energy-saving operation modes on the fly.  In those systems, if the operation
+mode chosen by the hardware attempts to save energy in an overly aggressive way,
+it may cause excess latencies to be visible to software, causing it to miss
+certain protocol requirements or target frame or sample rates etc.
+
+If there is a latency tolerance control mechanism for a given device available
+to software, the .set_latency_tolerance callback in that device's dev_pm_info
+structure should be populated.  The routine pointed to by it is should implement
+whatever is necessary to transfer the effective requirement value to the
+hardware.
+
+Whenever the effective latency tolerance changes for the device, its
+.set_latency_tolerance() callback will be executed and the effective value will
+be passed to it.  If that value is negative, which means that the list of
+latency tolerance requirements for the device is empty, the callback is expected
+to switch the underlying hardware latency tolerance control mechanism to an
+autonomous mode if available.  If that value is PM_QOS_LATENCY_ANY, in turn, and
+the hardware supports a special "no requirement" setting, the callback is
+expected to use it.  That allows software to prevent the hardware from
+automatically updating the device's latency tolerance in response to its power
+state changes (e.g. during transitions from D3cold to D0), which generally may
+be done in the autonomous latency tolerance control mode.
+
+If .set_latency_tolerance() is present for the device, sysfs attribute
+pm_qos_latency_tolerance_us will be present in the devivce's power directory.
+Then, user space can use that attribute to specify its latency tolerance
+requirement for the device, if any.  Writing "any" to it means "no requirement,
+but do not let the hardware control latency tolerance" and writing "auto" to it
+allows the hardware to be switched to the autonomous mode if there are no other
+requirements from the kernel side in the device's list.
+
+Kernel code can use the functions described above along with the
+DEV_PM_QOS_LATENCY_TOLERANCE device PM QoS type to add, remove and update
+latency tolerance requirements for devices.
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index c754e55f9dcb..84756f7f09d9 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -151,6 +151,14 @@ static int apply_constraint(struct dev_pm_qos_request *req,
 						     req);
 		}
 		break;
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
+		ret = pm_qos_update_target(&qos->latency_tolerance,
+					   &req->data.pnode, action, value);
+		if (ret) {
+			value = pm_qos_read_value(&qos->latency_tolerance);
+			req->dev->power.set_latency_tolerance(req->dev, value);
+		}
+		break;
 	case DEV_PM_QOS_FLAGS:
 		ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
 					  action, value);
@@ -194,6 +202,13 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
 	c->type = PM_QOS_MIN;
 	c->notifiers = n;
 
+	c = &qos->latency_tolerance;
+	plist_head_init(&c->list);
+	c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
+	c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
+	c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
+	c->type = PM_QOS_MIN;
+
 	INIT_LIST_HEAD(&qos->flags.list);
 
 	spin_lock_irq(&dev->power.lock);
@@ -247,6 +262,11 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 		memset(req, 0, sizeof(*req));
 	}
+	c = &qos->latency_tolerance;
+	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
+		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+		memset(req, 0, sizeof(*req));
+	}
 	f = &qos->flags;
 	list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
 		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
@@ -266,6 +286,40 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 	mutex_unlock(&dev_pm_qos_sysfs_mtx);
 }
 
+static bool dev_pm_qos_invalid_request(struct device *dev,
+				       struct dev_pm_qos_request *req)
+{
+	return !req || (req->type == DEV_PM_QOS_LATENCY_TOLERANCE
+			&& !dev->power.set_latency_tolerance);
+}
+
+static int __dev_pm_qos_add_request(struct device *dev,
+				    struct dev_pm_qos_request *req,
+				    enum dev_pm_qos_req_type type, s32 value)
+{
+	int ret = 0;
+
+	if (!dev || dev_pm_qos_invalid_request(dev, req))
+		return -EINVAL;
+
+	if (WARN(dev_pm_qos_request_active(req),
+		 "%s() called for already added request\n", __func__))
+		return -EINVAL;
+
+	if (IS_ERR(dev->power.qos))
+		ret = -ENODEV;
+	else if (!dev->power.qos)
+		ret = dev_pm_qos_constraints_allocate(dev);
+
+	trace_dev_pm_qos_add_request(dev_name(dev), type, value);
+	if (!ret) {
+		req->dev = dev;
+		req->type = type;
+		ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
+	}
+	return ret;
+}
+
 /**
  * dev_pm_qos_add_request - inserts new qos request into the list
  * @dev: target device for the constraint
@@ -291,31 +345,11 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
 			   enum dev_pm_qos_req_type type, s32 value)
 {
-	int ret = 0;
-
-	if (!dev || !req) /*guard against callers passing in null */
-		return -EINVAL;
-
-	if (WARN(dev_pm_qos_request_active(req),
-		 "%s() called for already added request\n", __func__))
-		return -EINVAL;
+	int ret;
 
 	mutex_lock(&dev_pm_qos_mtx);
-
-	if (IS_ERR(dev->power.qos))
-		ret = -ENODEV;
-	else if (!dev->power.qos)
-		ret = dev_pm_qos_constraints_allocate(dev);
-
-	trace_dev_pm_qos_add_request(dev_name(dev), type, value);
-	if (!ret) {
-		req->dev = dev;
-		req->type = type;
-		ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
-	}
-
+	ret = __dev_pm_qos_add_request(dev, req, type, value);
 	mutex_unlock(&dev_pm_qos_mtx);
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
@@ -343,6 +377,7 @@ static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
 
 	switch(req->type) {
 	case DEV_PM_QOS_RESUME_LATENCY:
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
 		curr_value = req->data.pnode.prio;
 		break;
 	case DEV_PM_QOS_FLAGS:
@@ -563,6 +598,10 @@ static void __dev_pm_qos_drop_user_request(struct device *dev,
 		req = dev->power.qos->resume_latency_req;
 		dev->power.qos->resume_latency_req = NULL;
 		break;
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
+		req = dev->power.qos->latency_tolerance_req;
+		dev->power.qos->latency_tolerance_req = NULL;
+		break;
 	case DEV_PM_QOS_FLAGS:
 		req = dev->power.qos->flags_req;
 		dev->power.qos->flags_req = NULL;
@@ -768,6 +807,67 @@ int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
 	pm_runtime_put(dev);
 	return ret;
 }
+
+/**
+ * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
+ * @dev: Device to obtain the user space latency tolerance for.
+ */
+s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
+{
+	s32 ret;
+
+	mutex_lock(&dev_pm_qos_mtx);
+	ret = IS_ERR_OR_NULL(dev->power.qos)
+		|| !dev->power.qos->latency_tolerance_req ?
+			PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
+			dev->power.qos->latency_tolerance_req->data.pnode.prio;
+	mutex_unlock(&dev_pm_qos_mtx);
+	return ret;
+}
+
+/**
+ * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
+ * @dev: Device to update the user space latency tolerance for.
+ * @val: New user space latency tolerance for @dev (negative values disable).
+ */
+int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
+{
+	int ret;
+
+	mutex_lock(&dev_pm_qos_mtx);
+
+	if (IS_ERR_OR_NULL(dev->power.qos)
+	    || !dev->power.qos->latency_tolerance_req) {
+		struct dev_pm_qos_request *req;
+
+		if (val < 0) {
+			ret = -EINVAL;
+			goto out;
+		}
+		req = kzalloc(sizeof(*req), GFP_KERNEL);
+		if (!req) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
+		if (ret < 0) {
+			kfree(req);
+			goto out;
+		}
+		dev->power.qos->latency_tolerance_req = req;
+	} else {
+		if (val < 0) {
+			__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
+			ret = 0;
+		} else {
+			ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
+		}
+	}
+
+ out:
+	mutex_unlock(&dev_pm_qos_mtx);
+	return ret;
+}
 #else /* !CONFIG_PM_RUNTIME */
 static void __dev_pm_qos_hide_latency_limit(struct device *dev) {}
 static void __dev_pm_qos_hide_flags(struct device *dev) {}
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 4e24955aac8a..95b181d1ca6d 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -246,6 +246,40 @@ static ssize_t pm_qos_resume_latency_store(struct device *dev,
 static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
 		   pm_qos_resume_latency_show, pm_qos_resume_latency_store);
 
+static ssize_t pm_qos_latency_tolerance_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	s32 value = dev_pm_qos_get_user_latency_tolerance(dev);
+
+	if (value < 0)
+		return sprintf(buf, "auto\n");
+	else if (value == PM_QOS_LATENCY_ANY)
+		return sprintf(buf, "any\n");
+
+	return sprintf(buf, "%d\n", value);
+}
+
+static ssize_t pm_qos_latency_tolerance_store(struct device *dev,
+					      struct device_attribute *attr,
+					      const char *buf, size_t n)
+{
+	s32 value;
+	int ret;
+
+	if (kstrtos32(buf, 0, &value)) {
+		if (!strcmp(buf, "auto") || !strcmp(buf, "auto\n"))
+			value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
+		else if (!strcmp(buf, "any") || !strcmp(buf, "any\n"))
+			value = PM_QOS_LATENCY_ANY;
+	}
+	ret = dev_pm_qos_update_user_latency_tolerance(dev, value);
+	return ret < 0 ? ret : n;
+}
+
+static DEVICE_ATTR(pm_qos_latency_tolerance_us, 0644,
+		   pm_qos_latency_tolerance_show, pm_qos_latency_tolerance_store);
+
 static ssize_t pm_qos_no_power_off_show(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -631,6 +665,17 @@ static struct attribute_group pm_qos_resume_latency_attr_group = {
 	.attrs	= pm_qos_resume_latency_attrs,
 };
 
+static struct attribute *pm_qos_latency_tolerance_attrs[] = {
+#ifdef CONFIG_PM_RUNTIME
+	&dev_attr_pm_qos_latency_tolerance_us.attr,
+#endif /* CONFIG_PM_RUNTIME */
+	NULL,
+};
+static struct attribute_group pm_qos_latency_tolerance_attr_group = {
+	.name	= power_group_name,
+	.attrs	= pm_qos_latency_tolerance_attrs,
+};
+
 static struct attribute *pm_qos_flags_attrs[] = {
 #ifdef CONFIG_PM_RUNTIME
 	&dev_attr_pm_qos_no_power_off.attr,
@@ -656,18 +701,23 @@ int dpm_sysfs_add(struct device *dev)
 		if (rc)
 			goto err_out;
 	}
-
 	if (device_can_wakeup(dev)) {
 		rc = sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
-		if (rc) {
-			if (pm_runtime_callbacks_present(dev))
-				sysfs_unmerge_group(&dev->kobj,
-						    &pm_runtime_attr_group);
-			goto err_out;
-		}
+		if (rc)
+			goto err_runtime;
+	}
+	if (dev->power.set_latency_tolerance) {
+		rc = sysfs_merge_group(&dev->kobj,
+				       &pm_qos_latency_tolerance_attr_group);
+		if (rc)
+			goto err_wakeup;
 	}
 	return 0;
 
+ err_wakeup:
+	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
+ err_runtime:
+	sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);
  err_out:
 	sysfs_remove_group(&dev->kobj, &pm_attr_group);
 	return rc;
@@ -710,6 +760,7 @@ void rpm_sysfs_remove(struct device *dev)
 
 void dpm_sysfs_remove(struct device *dev)
 {
+	sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group);
 	dev_pm_qos_constraints_destroy(dev);
 	rpm_sysfs_remove(dev);
 	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 8c6583a53a06..db2be5f3e030 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -582,6 +582,7 @@ struct dev_pm_info {
 	unsigned long		accounting_timestamp;
 #endif
 	struct pm_subsys_data	*subsys_data;  /* Owned by the subsystem. */
+	void (*set_latency_tolerance)(struct device *, s32);
 	struct dev_pm_qos	*qos;
 };
 
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 2d8ce50877d8..0b476019be55 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -33,6 +33,9 @@ enum pm_qos_flags_status {
 #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE	(2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE	0
 #define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE	0
+#define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE	0
+#define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT	(-1)
+#define PM_QOS_LATENCY_ANY			((s32)(~(__u32)0 >> 1))
 
 #define PM_QOS_FLAG_NO_POWER_OFF	(1 << 0)
 #define PM_QOS_FLAG_REMOTE_WAKEUP	(1 << 1)
@@ -50,6 +53,7 @@ struct pm_qos_flags_request {
 
 enum dev_pm_qos_req_type {
 	DEV_PM_QOS_RESUME_LATENCY = 1,
+	DEV_PM_QOS_LATENCY_TOLERANCE,
 	DEV_PM_QOS_FLAGS,
 };
 
@@ -89,8 +93,10 @@ struct pm_qos_flags {
 
 struct dev_pm_qos {
 	struct pm_qos_constraints resume_latency;
+	struct pm_qos_constraints latency_tolerance;
 	struct pm_qos_flags flags;
 	struct dev_pm_qos_request *resume_latency_req;
+	struct dev_pm_qos_request *latency_tolerance_req;
 	struct dev_pm_qos_request *flags_req;
 };
 
@@ -196,6 +202,8 @@ void dev_pm_qos_hide_latency_limit(struct device *dev);
 int dev_pm_qos_expose_flags(struct device *dev, s32 value);
 void dev_pm_qos_hide_flags(struct device *dev);
 int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set);
+s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev);
+int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val);
 
 static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev)
 {
@@ -215,6 +223,10 @@ static inline int dev_pm_qos_expose_flags(struct device *dev, s32 value)
 static inline void dev_pm_qos_hide_flags(struct device *dev) {}
 static inline int dev_pm_qos_update_flags(struct device *dev, s32 m, bool set)
 			{ return 0; }
+static inline s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
+			{ return PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; }
+static inline int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
+			{ return 0; }
 
 static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev) { return 0; }
 static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return 0; }
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index e23ae38e647f..884b77058864 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -173,6 +173,7 @@ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
 {
 	unsigned long flags;
 	int prev_value, curr_value, new_value;
+	int ret;
 
 	spin_lock_irqsave(&pm_qos_lock, flags);
 	prev_value = pm_qos_get_value(c);
@@ -208,13 +209,15 @@ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
 
 	trace_pm_qos_update_target(action, prev_value, curr_value);
 	if (prev_value != curr_value) {
-		blocking_notifier_call_chain(c->notifiers,
-					     (unsigned long)curr_value,
-					     NULL);
-		return 1;
+		ret = 1;
+		if (c->notifiers)
+			blocking_notifier_call_chain(c->notifiers,
+						     (unsigned long)curr_value,
+						     NULL);
 	} else {
-		return 0;
+		ret = 0;
 	}
+	return ret;
 }
 
 /**
-- 
cgit v1.2.3


From 9cb32acf095e806e864c29d060dd79580fcd3d4f Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 11 Feb 2014 00:35:46 +0100
Subject: ACPI / scan: Add bind/unbind callbacks to struct acpi_scan_handler

In some cases it may be necessary to perform certain setup/cleanup
operations on a device object representing a physical device after
it has been associated with an ACPI companion by acpi_bind_one() or
before disassociating it from that companion by acpi_unbind_one(),
respectively.  If there is a struct acpi_bus_type object for the
given device's bus type, the .setup()/.cleanup() callbacks from there
are executed for these purposes.  However, an analogous mechanism will
be necessary for devices whose bus types don't have corresponding
struct acpi_bus_type objects and that have specific ACPI scan handlers.

For those devices, add new .bind() and .unbind() callbacks to struct
acpi_scan_handler that will be executed by acpi_platform_notify()
right after the given device has been associated with an ACPI
comapnion and by acpi_platform_notify_remove() right before calling
acpi_unbind_one() for that device, respectively.

To make that work for scan handlers registering new devices in their
.attach() callbacks, modify acpi_scan_attach_handler() to set the
ACPI device object's handler field before calling .attach() from the
scan handler at hand.

This changeset includes a fix from Mika Westerberg.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/glue.c     | 12 ++++++++++++
 drivers/acpi/scan.c     |  9 +++++----
 include/acpi/acpi_bus.h |  2 ++
 3 files changed, 19 insertions(+), 4 deletions(-)

(limited to 'drivers')

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 0c789224d40d..f774c65ecb8b 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -287,6 +287,7 @@ EXPORT_SYMBOL_GPL(acpi_unbind_one);
 static int acpi_platform_notify(struct device *dev)
 {
 	struct acpi_bus_type *type = acpi_get_bus_type(dev);
+	struct acpi_device *adev;
 	int ret;
 
 	ret = acpi_bind_one(dev, NULL);
@@ -303,9 +304,14 @@ static int acpi_platform_notify(struct device *dev)
 		if (ret)
 			goto out;
 	}
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		goto out;
 
 	if (type && type->setup)
 		type->setup(dev);
+	else if (adev->handler && adev->handler->bind)
+		adev->handler->bind(dev);
 
  out:
 #if ACPI_GLUE_DEBUG
@@ -324,11 +330,17 @@ static int acpi_platform_notify(struct device *dev)
 
 static int acpi_platform_notify_remove(struct device *dev)
 {
+	struct acpi_device *adev = ACPI_COMPANION(dev);
 	struct acpi_bus_type *type;
 
+	if (!adev)
+		return 0;
+
 	type = acpi_get_bus_type(dev);
 	if (type && type->cleanup)
 		type->cleanup(dev);
+	else if (adev->handler && adev->handler->unbind)
+		adev->handler->unbind(dev);
 
 	acpi_unbind_one(dev);
 	return 0;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 57b053f424d1..9c4581fd5827 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2015,13 +2015,14 @@ static int acpi_scan_attach_handler(struct acpi_device *device)
 
 		handler = acpi_scan_match_handler(hwid->id, &devid);
 		if (handler) {
+			device->handler = handler;
 			ret = handler->attach(device, devid);
-			if (ret > 0) {
-				device->handler = handler;
+			if (ret > 0)
 				break;
-			} else if (ret < 0) {
+
+			device->handler = NULL;
+			if (ret < 0)
 				break;
-			}
 		}
 	}
 	return ret;
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 8256eb4ad057..c93bce469492 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -133,6 +133,8 @@ struct acpi_scan_handler {
 	struct list_head list_node;
 	int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
 	void (*detach)(struct acpi_device *dev);
+	void (*bind)(struct device *phys_dev);
+	void (*unbind)(struct device *phys_dev);
 	struct acpi_hotplug_profile hotplug;
 };
 
-- 
cgit v1.2.3


From 1a8f83515c1646e134163f0ab310362fae49fcca Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 11 Feb 2014 00:35:53 +0100
Subject: ACPI / LPSS: Support for device latency tolerance PM QoS

Add a new routine, acpi_lpss_set_ltr(), for setting latency tolerance
values for LPSS devices having LTR (Latency Tolerance Reporting)
registers.  Add .bind()/.unbind() callbacks to lpss_handler to set
the LPSS devices' power.set_latency_tolerance callback pointers to
acpi_lpss_set_ltr() during device addition and to clear them on
device removal, respectively.

That will cause the device latency tolerance PM QoS to work for
the devices in question as documented.

This changeset includes a fix from Mika Westerberg.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpi_lpss.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 6745fe137b9e..0a68fc6b5800 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -33,6 +33,13 @@ ACPI_MODULE_NAME("acpi_lpss");
 #define LPSS_GENERAL_UART_RTS_OVRD	BIT(3)
 #define LPSS_SW_LTR			0x10
 #define LPSS_AUTO_LTR			0x14
+#define LPSS_LTR_SNOOP_REQ		BIT(15)
+#define LPSS_LTR_SNOOP_MASK		0x0000FFFF
+#define LPSS_LTR_SNOOP_LAT_1US		0x800
+#define LPSS_LTR_SNOOP_LAT_32US		0xC00
+#define LPSS_LTR_SNOOP_LAT_SHIFT	5
+#define LPSS_LTR_SNOOP_LAT_CUTOFF	3000
+#define LPSS_LTR_MAX_VAL		0x3FF
 #define LPSS_TX_INT			0x20
 #define LPSS_TX_INT_MASK		BIT(1)
 
@@ -315,6 +322,17 @@ static int acpi_lpss_create_device(struct acpi_device *adev,
 	return ret;
 }
 
+static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
+{
+	return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
+static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
+			     unsigned int reg)
+{
+	writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 {
 	struct acpi_device *adev;
@@ -336,7 +354,7 @@ static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 		ret = -ENODEV;
 		goto out;
 	}
-	*val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+	*val = __lpss_reg_read(pdata, reg);
 
  out:
 	spin_unlock_irqrestore(&dev->power.lock, flags);
@@ -389,6 +407,37 @@ static struct attribute_group lpss_attr_group = {
 	.name = "lpss_ltr",
 };
 
+static void acpi_lpss_set_ltr(struct device *dev, s32 val)
+{
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	u32 ltr_mode, ltr_val;
+
+	ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
+	if (val < 0) {
+		if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
+			ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
+			__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+		}
+		return;
+	}
+	ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
+	if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
+		ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
+		val = LPSS_LTR_MAX_VAL;
+	} else if (val > LPSS_LTR_MAX_VAL) {
+		ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
+		val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
+	} else {
+		ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
+	}
+	ltr_val |= val;
+	__lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
+	if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
+		ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
+		__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+	}
+}
+
 static int acpi_lpss_platform_notify(struct notifier_block *nb,
 				     unsigned long action, void *data)
 {
@@ -426,9 +475,29 @@ static struct notifier_block acpi_lpss_nb = {
 	.notifier_call = acpi_lpss_platform_notify,
 };
 
+static void acpi_lpss_bind(struct device *dev)
+{
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+
+	if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
+		return;
+
+	if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
+		dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
+	else
+		dev_err(dev, "MMIO size insufficient to access LTR\n");
+}
+
+static void acpi_lpss_unbind(struct device *dev)
+{
+	dev->power.set_latency_tolerance = NULL;
+}
+
 static struct acpi_scan_handler lpss_handler = {
 	.ids = acpi_lpss_device_ids,
 	.attach = acpi_lpss_create_device,
+	.bind = acpi_lpss_bind,
+	.unbind = acpi_lpss_unbind,
 };
 
 void __init acpi_lpss_init(void)
-- 
cgit v1.2.3


From 71d821fdaec08afcbfb3cf258c0d64ea0e336ff3 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 11 Feb 2014 00:36:00 +0100
Subject: PM / QoS: Add type to dev_pm_qos_add_ancestor_request() arguments

Rework dev_pm_qos_add_ancestor_request() so that device PM QoS type
is passed to it as the third argument and make it support the
DEV_PM_QOS_LATENCY_TOLERANCE device PM QoS type (in addition to
DEV_PM_QOS_RESUME_LATENCY).

That will allow the drivers of devices without latency tolerance
hardware support to use their ancestors having it as proxies for
their latency tolerance requirements.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 Documentation/power/pm_qos_interface.txt |  6 ++++--
 drivers/base/power/qos.c                 | 22 +++++++++++++++++-----
 drivers/input/touchscreen/st1232.c       |  3 ++-
 include/linux/pm_qos.h                   |  7 +++++--
 4 files changed, 28 insertions(+), 10 deletions(-)

(limited to 'drivers')

diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt
index ed743bbad87c..a5da5c7e7128 100644
--- a/Documentation/power/pm_qos_interface.txt
+++ b/Documentation/power/pm_qos_interface.txt
@@ -134,9 +134,11 @@ The meaning of the return values is as follows:
 	PM_QOS_FLAGS_UNDEFINED: The device's PM QoS structure has not been
 			initialized or the list of requests is empty.
 
-int dev_pm_qos_add_ancestor_request(dev, handle, value)
+int dev_pm_qos_add_ancestor_request(dev, handle, type, value)
 Add a PM QoS request for the first direct ancestor of the given device whose
-power.ignore_children flag is unset.
+power.ignore_children flag is unset (for DEV_PM_QOS_RESUME_LATENCY requests)
+or whose power.set_latency_tolerance callback pointer is not NULL (for
+DEV_PM_QOS_LATENCY_TOLERANCE requests).
 
 int dev_pm_qos_expose_latency_limit(device, value)
 Add a request to the device's PM QoS list of resume latency constraints and
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 84756f7f09d9..36b9eb4862cb 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -565,20 +565,32 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier);
  * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
  * @dev: Device whose ancestor to add the request for.
  * @req: Pointer to the preallocated handle.
+ * @type: Type of the request.
  * @value: Constraint latency value.
  */
 int dev_pm_qos_add_ancestor_request(struct device *dev,
-				    struct dev_pm_qos_request *req, s32 value)
+				    struct dev_pm_qos_request *req,
+				    enum dev_pm_qos_req_type type, s32 value)
 {
 	struct device *ancestor = dev->parent;
 	int ret = -ENODEV;
 
-	while (ancestor && !ancestor->power.ignore_children)
-		ancestor = ancestor->parent;
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
+		while (ancestor && !ancestor->power.ignore_children)
+			ancestor = ancestor->parent;
 
+		break;
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
+		while (ancestor && !ancestor->power.set_latency_tolerance)
+			ancestor = ancestor->parent;
+
+		break;
+	default:
+		ancestor = NULL;
+	}
 	if (ancestor)
-		ret = dev_pm_qos_add_request(ancestor, req,
-					     DEV_PM_QOS_RESUME_LATENCY, value);
+		ret = dev_pm_qos_add_request(ancestor, req, type, value);
 
 	if (ret < 0)
 		req->dev = NULL;
diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 5c342b3139e8..3c0f57efe7b1 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -134,7 +134,8 @@ static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
 	} else if (!ts->low_latency_req.dev) {
 		/* First contact, request 100 us latency. */
 		dev_pm_qos_add_ancestor_request(&ts->client->dev,
-						&ts->low_latency_req, 100);
+						&ts->low_latency_req,
+						DEV_PM_QOS_RESUME_LATENCY, 100);
 	}
 
 	/* SYN_REPORT */
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 0b476019be55..9ab4bf7c4646 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -149,7 +149,8 @@ int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier);
 void dev_pm_qos_constraints_init(struct device *dev);
 void dev_pm_qos_constraints_destroy(struct device *dev);
 int dev_pm_qos_add_ancestor_request(struct device *dev,
-				    struct dev_pm_qos_request *req, s32 value);
+				    struct dev_pm_qos_request *req,
+				    enum dev_pm_qos_req_type type, s32 value);
 #else
 static inline enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev,
 							  s32 mask)
@@ -192,7 +193,9 @@ static inline void dev_pm_qos_constraints_destroy(struct device *dev)
 	dev->power.power_state = PMSG_INVALID;
 }
 static inline int dev_pm_qos_add_ancestor_request(struct device *dev,
-				    struct dev_pm_qos_request *req, s32 value)
+						  struct dev_pm_qos_request *req,
+						  enum dev_pm_qos_req_type type,
+						  s32 value)
 			{ return 0; }
 #endif
 
-- 
cgit v1.2.3


From 7d1af287320b41909c070f68ffe1591060a32769 Mon Sep 17 00:00:00 2001
From: Philipp Zabel <p.zabel@pengutronix.de>
Date: Thu, 27 Feb 2014 19:26:44 +0100
Subject: PM / domains: Turn latency warning into debug message

If devices don't provide latency data, this warning can be quite noisy until
the pm domain was enabled and disabled a few times. Turn this warning into
a debug message.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/domain.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index bfb8955c406c..dc127e5dec4b 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -42,7 +42,7 @@
 	struct gpd_timing_data *__td = &dev_gpd_data(dev)->td;			\
 	if (!__retval && __elapsed > __td->field) {				\
 		__td->field = __elapsed;					\
-		dev_warn(dev, name " latency exceeded, new value %lld ns\n",	\
+		dev_dbg(dev, name " latency exceeded, new value %lld ns\n",	\
 			__elapsed);						\
 		genpd->max_off_time_changed = true;				\
 		__td->constraint_changed = true;				\
-- 
cgit v1.2.3


From 5f59df79837bb809f3945613aba5519cd9755a53 Mon Sep 17 00:00:00 2001
From: Ulf Hansson <ulf.hansson@linaro.org>
Date: Sat, 1 Mar 2014 11:56:04 +0100
Subject: PM / runtime: Fetch runtime PM callbacks using a macro

While fetching the proper runtime PM callback, we walk the hierarchy of
device's power domains, subsystems and drivers.

This is common for rpm_suspend(), rpm_idle() and rpm_resume(). Let's
clean up the code by using a macro that handles this.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/runtime.c | 78 ++++++++++++++++++++++----------------------
 1 file changed, 39 insertions(+), 39 deletions(-)

(limited to 'drivers')

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 72e00e66ecc5..ac495b1357fa 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -13,6 +13,42 @@
 #include <trace/events/rpm.h>
 #include "power.h"
 
+#define RPM_GET_CALLBACK(dev, cb)				\
+({								\
+	int (*__rpm_cb)(struct device *__d);			\
+								\
+	if (dev->pm_domain)					\
+		__rpm_cb = dev->pm_domain->ops.cb;		\
+	else if (dev->type && dev->type->pm)			\
+		__rpm_cb = dev->type->pm->cb;			\
+	else if (dev->class && dev->class->pm)			\
+		__rpm_cb = dev->class->pm->cb;			\
+	else if (dev->bus && dev->bus->pm)			\
+		__rpm_cb = dev->bus->pm->cb;			\
+	else							\
+		__rpm_cb = NULL;				\
+								\
+	if (!__rpm_cb && dev->driver && dev->driver->pm)	\
+		__rpm_cb = dev->driver->pm->cb;			\
+								\
+	__rpm_cb;						\
+})
+
+static int (*rpm_get_suspend_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_suspend);
+}
+
+static int (*rpm_get_resume_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_resume);
+}
+
+static int (*rpm_get_idle_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_idle);
+}
+
 static int rpm_resume(struct device *dev, int rpmflags);
 static int rpm_suspend(struct device *dev, int rpmflags);
 
@@ -310,19 +346,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
 
 	dev->power.idle_notification = true;
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_idle;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_idle;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_idle;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_idle;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_idle;
+	callback = rpm_get_idle_cb(dev);
 
 	if (callback)
 		retval = __rpm_callback(callback, dev);
@@ -492,19 +516,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 
 	__update_runtime_status(dev, RPM_SUSPENDING);
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_suspend;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_suspend;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_suspend;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_suspend;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_suspend;
+	callback = rpm_get_suspend_cb(dev);
 
 	retval = rpm_callback(callback, dev);
 	if (retval)
@@ -724,19 +736,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 
 	__update_runtime_status(dev, RPM_RESUMING);
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_resume;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_resume;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_resume;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_resume;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_resume;
+	callback = rpm_get_resume_cb(dev);
 
 	retval = rpm_callback(callback, dev);
 	if (retval) {
-- 
cgit v1.2.3


From 37f204164dfb0186a0caf20bc3e3120080bcd788 Mon Sep 17 00:00:00 2001
From: Ulf Hansson <ulf.hansson@linaro.org>
Date: Sat, 1 Mar 2014 11:56:05 +0100
Subject: PM: Add pm_runtime_suspend|resume_force functions

This patch provides two new runtime PM helper functions which intend to
be used from system suspend/resume callbacks, to make sure devices are
put into low power state during system suspend and brought back to full
power at system resume.

The prerequisite is to have all levels of a device's runtime PM
callbacks to be defined through the SET_PM_RUNTIME_PM_OPS macro, which
means these are available for CONFIG_PM.

By using the new runtime PM helper functions especially the two
scenarios below will be addressed.

1) The PM core prevents .runtime_suspend callbacks from being invoked
during system suspend. That means even for a runtime PM centric
subsystem and driver, the device needs to be put into low power state
from a system suspend callback. Otherwise it may very well be left in
full power state (runtime resumed) while the system is suspended. By
using the new helper functions, we make sure to walk the hierarchy of
a device's power domain, subsystem and driver.

2) Subsystems and drivers need to cope with all the combinations of
CONFIG_PM_SLEEP and CONFIG_PM_RUNTIME. The two new helper functions
smothly addresses this.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/Makefile  |  3 +-
 drivers/base/power/runtime.c | 84 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm_runtime.h   |  4 +++
 3 files changed, 89 insertions(+), 2 deletions(-)

(limited to 'drivers')

diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 2e58ebb1f6c0..1cb8544598d5 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -1,6 +1,5 @@
-obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o common.o qos.o
+obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o common.o qos.o runtime.o
 obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
-obj-$(CONFIG_PM_RUNTIME)	+= runtime.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 obj-$(CONFIG_PM_OPP)	+= opp.o
 obj-$(CONFIG_PM_GENERIC_DOMAINS)	+=  domain.o domain_governor.o
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index ac495b1357fa..4776cf528d08 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -44,6 +44,7 @@ static int (*rpm_get_resume_cb(struct device *dev))(struct device *)
 	return RPM_GET_CALLBACK(dev, runtime_resume);
 }
 
+#ifdef CONFIG_PM_RUNTIME
 static int (*rpm_get_idle_cb(struct device *dev))(struct device *)
 {
 	return RPM_GET_CALLBACK(dev, runtime_idle);
@@ -1401,3 +1402,86 @@ void pm_runtime_remove(struct device *dev)
 	if (dev->power.irq_safe && dev->parent)
 		pm_runtime_put(dev->parent);
 }
+#endif
+
+/**
+ * pm_runtime_force_suspend - Force a device into suspend state if needed.
+ * @dev: Device to suspend.
+ *
+ * Disable runtime PM so we safely can check the device's runtime PM status and
+ * if it is active, invoke it's .runtime_suspend callback to bring it into
+ * suspend state. Keep runtime PM disabled to preserve the state unless we
+ * encounter errors.
+ *
+ * Typically this function may be invoked from a system suspend callback to make
+ * sure the device is put into low power state.
+ */
+int pm_runtime_force_suspend(struct device *dev)
+{
+	int (*callback)(struct device *);
+	int ret = 0;
+
+	pm_runtime_disable(dev);
+
+	/*
+	 * Note that pm_runtime_status_suspended() returns false while
+	 * !CONFIG_PM_RUNTIME, which means the device will be put into low
+	 * power state.
+	 */
+	if (pm_runtime_status_suspended(dev))
+		return 0;
+
+	callback = rpm_get_suspend_cb(dev);
+
+	if (!callback) {
+		ret = -ENOSYS;
+		goto err;
+	}
+
+	ret = callback(dev);
+	if (ret)
+		goto err;
+
+	pm_runtime_set_suspended(dev);
+	return 0;
+err:
+	pm_runtime_enable(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
+
+/**
+ * pm_runtime_force_resume - Force a device into resume state.
+ * @dev: Device to resume.
+ *
+ * Prior invoking this function we expect the user to have brought the device
+ * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
+ * those actions and brings the device into full power. We update the runtime PM
+ * status and re-enables runtime PM.
+ *
+ * Typically this function may be invoked from a system resume callback to make
+ * sure the device is put into full power state.
+ */
+int pm_runtime_force_resume(struct device *dev)
+{
+	int (*callback)(struct device *);
+	int ret = 0;
+
+	callback = rpm_get_resume_cb(dev);
+
+	if (!callback) {
+		ret = -ENOSYS;
+		goto out;
+	}
+
+	ret = callback(dev);
+	if (ret)
+		goto out;
+
+	pm_runtime_set_active(dev);
+	pm_runtime_mark_last_busy(dev);
+out:
+	pm_runtime_enable(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_force_resume);
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 16c9a62fa1c0..2a5897a4afbc 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -26,9 +26,13 @@
 #ifdef CONFIG_PM
 extern int pm_generic_runtime_suspend(struct device *dev);
 extern int pm_generic_runtime_resume(struct device *dev);
+extern int pm_runtime_force_suspend(struct device *dev);
+extern int pm_runtime_force_resume(struct device *dev);
 #else
 static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
+static inline int pm_runtime_force_suspend(struct device *dev) { return 0; }
+static inline int pm_runtime_force_resume(struct device *dev) { return 0; }
 #endif
 
 #ifdef CONFIG_PM_RUNTIME
-- 
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