Merge branches 'pm-pci' and 'pm-core'

* pm-pci:
  PCI / PM: Fix small typo in documentation
  PCI / PM: constify pci_platform_pm_ops structure

* pm-core:
  PM / core: fix typo in documentation
  PM / runtime: Add new helper for conditional usage count incrementation
  MAINTAINERS: Add an entry for the PM core
  PM / runtime: Re-init runtime PM states at probe error and driver unbind
  PM / sleep: prohibit devices probing during suspend/hibernation

Author: rafaeljw

Documentation/power/pci.txt

@@ -999,7 +999,7 @@ from its probe routine to make runtime PM work for the device.
 
 It is important to remember that the driver's runtime_suspend() callback
 may be executed right after the usage counter has been decremented, because
-user space may already have cuased the pm_runtime_allow() helper function
+user space may already have caused the pm_runtime_allow() helper function
 unblocking the runtime PM of the device to run via sysfs, so the driver must
 be prepared to cope with that.
 

Documentation/power/runtime_pm.txt

@@ -371,6 +371,12 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
     - increment the device's usage counter, run pm_runtime_resume(dev) and
       return its result
 
+  int pm_runtime_get_if_in_use(struct device *dev);
+    - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
+      runtime PM status is RPM_ACTIVE and the runtime PM usage counter is
+      nonzero, increment the counter and return 1; otherwise return 0 without
+      changing the counter
+
   void pm_runtime_put_noidle(struct device *dev);
     - decrement the device's usage counter
 

MAINTAINERS

@@ -8447,6 +8447,17 @@ F:	fs/timerfd.c
 F:	include/linux/timer*
 F:	kernel/time/*timer*
 
+POWER MANAGEMENT CORE
+M:	"Rafael J. Wysocki" <[email protected]>
+L:	[email protected]
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
+S:	Supported
+F:	drivers/base/power/
+F:	include/linux/pm.h
+F:	include/linux/pm_*
+F:	include/linux/powercap.h
+F:	drivers/powercap/
+
 POWER SUPPLY CLASS/SUBSYSTEM and DRIVERS
 M:	Sebastian Reichel <[email protected]>
 M:	Dmitry Eremin-Solenikov <[email protected]>

drivers/base/base.h

@@ -131,6 +131,8 @@ extern void device_remove_groups(struct device *dev,
 extern char *make_class_name(const char *name, struct kobject *kobj);
 
 extern int devres_release_all(struct device *dev);
+extern void device_block_probing(void);
+extern void device_unblock_probing(void);
 
 /* /sys/devices directory */
 extern struct kset *devices_kset;

drivers/base/dd.c

@@ -54,6 +54,13 @@ static LIST_HEAD(deferred_probe_active_list);
 static struct workqueue_struct *deferred_wq;
 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
 
+/*
+ * In some cases, like suspend to RAM or hibernation, It might be reasonable
+ * to prohibit probing of devices as it could be unsafe.
+ * Once defer_all_probes is true all drivers probes will be forcibly deferred.
+ */
+static bool defer_all_probes;
+
 /*
  * deferred_probe_work_func() - Retry probing devices in the active list.
  */
@@ -171,6 +178,30 @@ static void driver_deferred_probe_trigger(void)
 	queue_work(deferred_wq, &deferred_probe_work);
 }
 
+/**
+ * device_block_probing() - Block/defere device's probes
+ *
+ *	It will disable probing of devices and defer their probes instead.
+ */
+void device_block_probing(void)
+{
+	defer_all_probes = true;
+	/* sync with probes to avoid races. */
+	wait_for_device_probe();
+}
+
+/**
+ * device_unblock_probing() - Unblock/enable device's probes
+ *
+ *	It will restore normal behavior and trigger re-probing of deferred
+ * devices.
+ */
+void device_unblock_probing(void)
+{
+	defer_all_probes = false;
+	driver_deferred_probe_trigger();
+}
+
 /**
  * deferred_probe_initcall() - Enable probing of deferred devices
  *
@@ -280,9 +311,20 @@ static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
 
 static int really_probe(struct device *dev, struct device_driver *drv)
 {
-	int ret = 0;
+	int ret = -EPROBE_DEFER;
 	int local_trigger_count = atomic_read(&deferred_trigger_count);
 
+	if (defer_all_probes) {
+		/*
+		 * Value of defer_all_probes can be set only by
+		 * device_defer_all_probes_enable() which, in turn, will call
+		 * wait_for_device_probe() right after that to avoid any races.
+		 */
+		dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
+		driver_deferred_probe_add(dev);
+		return ret;
+	}
+
 	atomic_inc(&probe_count);
 	pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
 		 drv->bus->name, __func__, drv->name, dev_name(dev));
@@ -347,6 +389,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	dev_set_drvdata(dev, NULL);
 	if (dev->pm_domain && dev->pm_domain->dismiss)
 		dev->pm_domain->dismiss(dev);
+	pm_runtime_reinit(dev);
 
 	switch (ret) {
 	case -EPROBE_DEFER:
@@ -400,6 +443,10 @@ int driver_probe_done(void)
  */
 void wait_for_device_probe(void)
 {
+	/* wait for the deferred probe workqueue to finish */
+	if (driver_deferred_probe_enable)
+		flush_workqueue(deferred_wq);
+
 	/* wait for the known devices to complete their probing */
 	wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
 	async_synchronize_full();
@@ -702,6 +749,7 @@ static void __device_release_driver(struct device *dev)
 		dev_set_drvdata(dev, NULL);
 		if (dev->pm_domain && dev->pm_domain->dismiss)
 			dev->pm_domain->dismiss(dev);
+		pm_runtime_reinit(dev);
 
 		klist_remove(&dev->p->knode_driver);
 		if (dev->bus)

drivers/base/power/common.c

@@ -112,7 +112,7 @@ EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
 
 /**
  * dev_pm_domain_detach - Detach a device from its PM domain.
- * @dev: Device to attach.
+ * @dev: Device to detach.
  * @power_off: Used to indicate whether we should power off the device.
  *
  * This functions will reverse the actions from dev_pm_domain_attach() and thus

drivers/base/power/main.c

@@ -963,6 +963,9 @@ void dpm_complete(pm_message_t state)
 	}
 	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
+
+	/* Allow device probing and trigger re-probing of deferred devices */
+	device_unblock_probing();
 	trace_suspend_resume(TPS("dpm_complete"), state.event, false);
 }
 
@@ -1624,6 +1627,20 @@ int dpm_prepare(pm_message_t state)
 	trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
 	might_sleep();
 
+	/*
+	 * Give a chance for the known devices to complete their probes, before
+	 * disable probing of devices. This sync point is important at least
+	 * at boot time + hibernation restore.
+	 */
+	wait_for_device_probe();
+	/*
+	 * It is unsafe if probing of devices will happen during suspend or
+	 * hibernation and system behavior will be unpredictable in this case.
+	 * So, let's prohibit device's probing here and defer their probes
+	 * instead. The normal behavior will be restored in dpm_complete().
+	 */
+	device_block_probing();
+
 	mutex_lock(&dpm_list_mtx);
 	while (!list_empty(&dpm_list)) {
 		struct device *dev = to_device(dpm_list.next);

drivers/base/power/power.h

@@ -18,6 +18,7 @@ static inline void pm_runtime_early_init(struct device *dev)
 }
 
 extern void pm_runtime_init(struct device *dev);
+extern void pm_runtime_reinit(struct device *dev);
 extern void pm_runtime_remove(struct device *dev);
 
 struct wake_irq {
@@ -84,6 +85,7 @@ static inline void pm_runtime_early_init(struct device *dev)
 }
 
 static inline void pm_runtime_init(struct device *dev) {}
+static inline void pm_runtime_reinit(struct device *dev) {}
 static inline void pm_runtime_remove(struct device *dev) {}
 
 static inline int dpm_sysfs_add(struct device *dev) { return 0; }

drivers/base/power/runtime.c

@@ -965,6 +965,30 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 
+/**
+ * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
+ * @dev: Device to handle.
+ *
+ * Return -EINVAL if runtime PM is disabled for the device.
+ *
+ * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
+ * and the runtime PM usage counter is nonzero, increment the counter and
+ * return 1.  Otherwise return 0 without changing the counter.
+ */
+int pm_runtime_get_if_in_use(struct device *dev)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	retval = dev->power.disable_depth > 0 ? -EINVAL :
+		dev->power.runtime_status == RPM_ACTIVE
+			&& atomic_inc_not_zero(&dev->power.usage_count);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
+
 /**
  * __pm_runtime_set_status - Set runtime PM status of a device.
  * @dev: Device to handle.
@@ -1389,19 +1413,33 @@ void pm_runtime_init(struct device *dev)
 	init_waitqueue_head(&dev->power.wait_queue);
 }
 
+/**
+ * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
+ * @dev: Device object to re-initialize.
+ */
+void pm_runtime_reinit(struct device *dev)
+{
+	if (!pm_runtime_enabled(dev)) {
+		if (dev->power.runtime_status == RPM_ACTIVE)
+			pm_runtime_set_suspended(dev);
+		if (dev->power.irq_safe) {
+			spin_lock_irq(&dev->power.lock);
+			dev->power.irq_safe = 0;
+			spin_unlock_irq(&dev->power.lock);
+			if (dev->parent)
+				pm_runtime_put(dev->parent);
+		}
+	}
+}
+
 /**
  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
  * @dev: Device object being removed from device hierarchy.
  */
 void pm_runtime_remove(struct device *dev)
 {
 	__pm_runtime_disable(dev, false);
-
-	/* Change the status back to 'suspended' to match the initial status. */
-	if (dev->power.runtime_status == RPM_ACTIVE)
-		pm_runtime_set_suspended(dev);
-	if (dev->power.irq_safe && dev->parent)
-		pm_runtime_put(dev->parent);
+	pm_runtime_reinit(dev);
 }
 
 /**

drivers/pci/pci-acpi.c

@@ -529,7 +529,7 @@ static bool acpi_pci_need_resume(struct pci_dev *dev)
 	return !!adev->power.flags.dsw_present;
 }
 
-static struct pci_platform_pm_ops acpi_pci_platform_pm = {
+static const struct pci_platform_pm_ops acpi_pci_platform_pm = {
 	.is_manageable = acpi_pci_power_manageable,
 	.set_state = acpi_pci_set_power_state,
 	.choose_state = acpi_pci_choose_state,

drivers/pci/pci.c

@@ -527,9 +527,9 @@ static void pci_restore_bars(struct pci_dev *dev)
 		pci_update_resource(dev, i);
 }
 
-static struct pci_platform_pm_ops *pci_platform_pm;
+static const struct pci_platform_pm_ops *pci_platform_pm;
 
-int pci_set_platform_pm(struct pci_platform_pm_ops *ops)
+int pci_set_platform_pm(const struct pci_platform_pm_ops *ops)
 {
 	if (!ops->is_manageable || !ops->set_state || !ops->choose_state
 	    || !ops->sleep_wake)

drivers/pci/pci.h

@@ -68,7 +68,7 @@ struct pci_platform_pm_ops {
 	bool (*need_resume)(struct pci_dev *dev);
 };
 
-int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
+int pci_set_platform_pm(const struct pci_platform_pm_ops *ops);
 void pci_update_current_state(struct pci_dev *dev, pci_power_t state);
 void pci_power_up(struct pci_dev *dev);
 void pci_disable_enabled_device(struct pci_dev *dev);

include/linux/pm_runtime.h

@@ -39,6 +39,7 @@ extern int pm_runtime_force_resume(struct device *dev);
 extern int __pm_runtime_idle(struct device *dev, int rpmflags);
 extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
 extern int __pm_runtime_resume(struct device *dev, int rpmflags);
+extern int pm_runtime_get_if_in_use(struct device *dev);
 extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
 extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
 extern int pm_runtime_barrier(struct device *dev);
@@ -143,6 +144,10 @@ static inline int pm_schedule_suspend(struct device *dev, unsigned int delay)
 {
 	return -ENOSYS;
 }
+static inline int pm_runtime_get_if_in_use(struct device *dev)
+{
+	return -EINVAL;
+}
 static inline int __pm_runtime_set_status(struct device *dev,
 					    unsigned int status) { return 0; }
 static inline int pm_runtime_barrier(struct device *dev) { return 0; }