+static DEFINE_MUTEX(pci_acpi_pm_notify_mtx);
+
+/**
+ * pci_acpi_wake_bus - Wake-up notification handler for root buses.
+ * @handle: ACPI handle of a device the notification is for.
+ * @event: Type of the signaled event.
+ * @context: PCI root bus to wake up devices on.
+ */
+static void pci_acpi_wake_bus(acpi_handle handle, u32 event, void *context)
+{
+ struct pci_bus *pci_bus = context;
+
+ if (event == ACPI_NOTIFY_DEVICE_WAKE && pci_bus)
+ pci_pme_wakeup_bus(pci_bus);
+}
+
+/**
+ * pci_acpi_wake_dev - Wake-up notification handler for PCI devices.
+ * @handle: ACPI handle of a device the notification is for.
+ * @event: Type of the signaled event.
+ * @context: PCI device object to wake up.
+ */
+static void pci_acpi_wake_dev(acpi_handle handle, u32 event, void *context)
+{
+ struct pci_dev *pci_dev = context;
+
+ if (event == ACPI_NOTIFY_DEVICE_WAKE && pci_dev) {
+ pci_check_pme_status(pci_dev);
+ pm_runtime_resume(&pci_dev->dev);
+ if (pci_dev->subordinate)
+ pci_pme_wakeup_bus(pci_dev->subordinate);
+ }
+}
+
+/**
+ * add_pm_notifier - Register PM notifier for given ACPI device.
+ * @dev: ACPI device to add the notifier for.
+ * @context: PCI device or bus to check for PME status if an event is signaled.
+ *
+ * NOTE: @dev need not be a run-wake or wake-up device to be a valid source of
+ * PM wake-up events. For example, wake-up events may be generated for bridges
+ * if one of the devices below the bridge is signaling PME, even if the bridge
+ * itself doesn't have a wake-up GPE associated with it.
+ */
+static acpi_status add_pm_notifier(struct acpi_device *dev,
+ acpi_notify_handler handler,
+ void *context)
+{
+ acpi_status status = AE_ALREADY_EXISTS;
+
+ mutex_lock(&pci_acpi_pm_notify_mtx);
+
+ if (dev->wakeup.flags.notifier_present)
+ goto out;
+
+ status = acpi_install_notify_handler(dev->handle,
+ ACPI_SYSTEM_NOTIFY,
+ handler, context);
+ if (ACPI_FAILURE(status))
+ goto out;
+
+ dev->wakeup.flags.notifier_present = true;
+
+ out:
+ mutex_unlock(&pci_acpi_pm_notify_mtx);
+ return status;
+}
+
+/**
+ * remove_pm_notifier - Unregister PM notifier from given ACPI device.
+ * @dev: ACPI device to remove the notifier from.
+ */
+static acpi_status remove_pm_notifier(struct acpi_device *dev,
+ acpi_notify_handler handler)
+{
+ acpi_status status = AE_BAD_PARAMETER;
+
+ mutex_lock(&pci_acpi_pm_notify_mtx);
+
+ if (!dev->wakeup.flags.notifier_present)
+ goto out;
+
+ status = acpi_remove_notify_handler(dev->handle,
+ ACPI_SYSTEM_NOTIFY,
+ handler);
+ if (ACPI_FAILURE(status))
+ goto out;
+
+ dev->wakeup.flags.notifier_present = false;
+
+ out:
+ mutex_unlock(&pci_acpi_pm_notify_mtx);
+ return status;
+}
+
+/**
+ * pci_acpi_add_bus_pm_notifier - Register PM notifier for given PCI bus.
+ * @dev: ACPI device to add the notifier for.
+ * @pci_bus: PCI bus to walk checking for PME status if an event is signaled.
+ */
+acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev,
+ struct pci_bus *pci_bus)
+{
+ return add_pm_notifier(dev, pci_acpi_wake_bus, pci_bus);
+}
+
+/**
+ * pci_acpi_remove_bus_pm_notifier - Unregister PCI bus PM notifier.
+ * @dev: ACPI device to remove the notifier from.
+ */
+acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev)
+{
+ return remove_pm_notifier(dev, pci_acpi_wake_bus);
+}
+
+/**
+ * pci_acpi_add_pm_notifier - Register PM notifier for given PCI device.
+ * @dev: ACPI device to add the notifier for.
+ * @pci_dev: PCI device to check for the PME status if an event is signaled.
+ */
+acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev,
+ struct pci_dev *pci_dev)
+{
+ return add_pm_notifier(dev, pci_acpi_wake_dev, pci_dev);
+}
+
+/**
+ * pci_acpi_remove_pm_notifier - Unregister PCI device PM notifier.
+ * @dev: ACPI device to remove the notifier from.
+ */
+acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
+{
+ return remove_pm_notifier(dev, pci_acpi_wake_dev);
+}
+