drivers/pci/pcie/pme.c - kernel/msm-4.9 - Gitiles

 /*
  * PCIe Native PME support
  *
  * Copyright (C) 2007 - 2009 Intel Corp
  * Copyright (C) 2007 - 2009 Shaohua Li <shaohua.li@intel.com>
  * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License V2.  See the file "COPYING" in the main directory of this archive
  * for more details.
  */

 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/pcieport_if.h>
 #include <linux/pm_runtime.h>

 #include "../pci.h"
 #include "portdrv.h"

 /*
  * If this switch is set, MSI will not be used for PCIe PME signaling.  This
  * causes the PCIe port driver to use INTx interrupts only, but it turns out
  * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
  * wake-up from system sleep states.
  */
 bool pcie_pme_msi_disabled;

 static int __init pcie_pme_setup(char *str)
 {
 	if (!strncmp(str, "nomsi", 5))
 		pcie_pme_msi_disabled = true;

 	return 1;
 }
 __setup("pcie_pme=", pcie_pme_setup);

 enum pme_suspend_level {
 	PME_SUSPEND_NONE = 0,
 	PME_SUSPEND_WAKEUP,
 	PME_SUSPEND_NOIRQ,
 };

 struct pcie_pme_service_data {
 	spinlock_t lock;
 	struct pcie_device *srv;
 	struct work_struct work;
 	enum pme_suspend_level suspend_level;
 };

 /**
  * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
  * @dev: PCIe root port or event collector.
  * @enable: Enable or disable the interrupt.
  */
 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
 {
 	if (enable)
 		pcie_capability_set_word(dev, PCI_EXP_RTCTL,
 					 PCI_EXP_RTCTL_PMEIE);
 	else
 		pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
 					   PCI_EXP_RTCTL_PMEIE);
 }

 /**
  * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
  * @bus: PCI bus to scan.
  *
  * Scan given PCI bus and all buses under it for devices asserting PME#.
  */
 static bool pcie_pme_walk_bus(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 	bool ret = false;

 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		/* Skip PCIe devices in case we started from a root port. */
 		if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
 			if (dev->pme_poll)
 				dev->pme_poll = false;

 			pci_wakeup_event(dev);
 			pm_request_resume(&dev->dev);
 			ret = true;
 		}

 		if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
 			ret = true;
 	}

 	return ret;
 }

 /**
  * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
  * @bus: Secondary bus of the bridge.
  * @devfn: Device/function number to check.
  *
  * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
  * PCIe PME message.  In such that case the bridge should use the Requester ID
  * of device/function number 0 on its secondary bus.
  */
 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
 {
 	struct pci_dev *dev;
 	bool found = false;

 	if (devfn)
 		return false;

 	dev = pci_dev_get(bus->self);
 	if (!dev)
 		return false;

 	if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
 		down_read(&pci_bus_sem);
 		if (pcie_pme_walk_bus(bus))
 			found = true;
 		up_read(&pci_bus_sem);
 	}

 	pci_dev_put(dev);
 	return found;
 }

 /**
  * pcie_pme_handle_request - Find device that generated PME and handle it.
  * @port: Root port or event collector that generated the PME interrupt.
  * @req_id: PCIe Requester ID of the device that generated the PME.
  */
 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
 {
 	u8 busnr = req_id >> 8, devfn = req_id & 0xff;
 	struct pci_bus *bus;
 	struct pci_dev *dev;
 	bool found = false;

 	/* First, check if the PME is from the root port itself. */
 	if (port->devfn == devfn && port->bus->number == busnr) {
 		if (port->pme_poll)
 			port->pme_poll = false;

 		if (pci_check_pme_status(port)) {
 			pm_request_resume(&port->dev);
 			found = true;
 		} else {
 			/*
 			 * Apparently, the root port generated the PME on behalf
 			 * of a non-PCIe device downstream.  If this is done by
 			 * a root port, the Requester ID field in its status
 			 * register may contain either the root port's, or the
 			 * source device's information (PCI Express Base
 			 * Specification, Rev. 2.0, Section 6.1.9).
 			 */
 			down_read(&pci_bus_sem);
 			found = pcie_pme_walk_bus(port->subordinate);
 			up_read(&pci_bus_sem);
 		}
 		goto out;
 	}

 	/* Second, find the bus the source device is on. */
 	bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
 	if (!bus)
 		goto out;

 	/* Next, check if the PME is from a PCIe-PCI bridge. */
 	found = pcie_pme_from_pci_bridge(bus, devfn);
 	if (found)
 		goto out;

 	/* Finally, try to find the PME source on the bus. */
 	down_read(&pci_bus_sem);
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		pci_dev_get(dev);
 		if (dev->devfn == devfn) {
 			found = true;
 			break;
 		}
 		pci_dev_put(dev);
 	}
 	up_read(&pci_bus_sem);

 	if (found) {
 		/* The device is there, but we have to check its PME status. */
 		found = pci_check_pme_status(dev);
 		if (found) {
 			if (dev->pme_poll)
 				dev->pme_poll = false;

 			pci_wakeup_event(dev);
 			pm_request_resume(&dev->dev);
 		}
 		pci_dev_put(dev);
 	} else if (devfn) {
 		/*
 		 * The device is not there, but we can still try to recover by
 		 * assuming that the PME was reported by a PCIe-PCI bridge that
 		 * used devfn different from zero.
 		 */
 		dev_dbg(&port->dev, "PME interrupt generated for non-existent device %02x:%02x.%d\n",
 			busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
 		found = pcie_pme_from_pci_bridge(bus, 0);
 	}

  out:
 	if (!found)
 		dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
 }

 /**
  * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
  * @work: Work structure giving access to service data.
  */
 static void pcie_pme_work_fn(struct work_struct *work)
 {
 	struct pcie_pme_service_data *data =
 			container_of(work, struct pcie_pme_service_data, work);
 	struct pci_dev *port = data->srv->port;
 	u32 rtsta;

 	spin_lock_irq(&data->lock);

 	for (;;) {
 		if (data->suspend_level != PME_SUSPEND_NONE)
 			break;

 		pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
 		if (rtsta & PCI_EXP_RTSTA_PME) {
 			/*
 			 * Clear PME status of the port.  If there are other
 			 * pending PMEs, the status will be set again.
 			 */
 			pcie_clear_root_pme_status(port);

 			spin_unlock_irq(&data->lock);
 			pcie_pme_handle_request(port, rtsta & 0xffff);
 			spin_lock_irq(&data->lock);

 			continue;
 		}

 		/* No need to loop if there are no more PMEs pending. */
 		if (!(rtsta & PCI_EXP_RTSTA_PENDING))
 			break;

 		spin_unlock_irq(&data->lock);
 		cpu_relax();
 		spin_lock_irq(&data->lock);
 	}

 	if (data->suspend_level == PME_SUSPEND_NONE)
 		pcie_pme_interrupt_enable(port, true);

 	spin_unlock_irq(&data->lock);
 }

 /**
  * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
  * @irq: Interrupt vector.
  * @context: Interrupt context pointer.
  */
 static irqreturn_t pcie_pme_irq(int irq, void *context)
 {
 	struct pci_dev *port;
 	struct pcie_pme_service_data *data;
 	u32 rtsta;
 	unsigned long flags;

 	port = ((struct pcie_device *)context)->port;
 	data = get_service_data((struct pcie_device *)context);

 	spin_lock_irqsave(&data->lock, flags);
 	pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);

 	if (!(rtsta & PCI_EXP_RTSTA_PME)) {
 		spin_unlock_irqrestore(&data->lock, flags);
 		return IRQ_NONE;
 	}

 	pcie_pme_interrupt_enable(port, false);
 	spin_unlock_irqrestore(&data->lock, flags);

 	/* We don't use pm_wq, because it's freezable. */
 	schedule_work(&data->work);

 	return IRQ_HANDLED;
 }

 /**
  * pcie_pme_set_native - Set the PME interrupt flag for given device.
  * @dev: PCI device to handle.
  * @ign: Ignored.
  */
 static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
 {
 	dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");

 	device_set_run_wake(&dev->dev, true);
 	dev->pme_interrupt = true;
 	return 0;
 }

 /**
  * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
  * @port: PCIe root port or event collector to handle.
  *
  * For each device below given root port, including the port itself (or for each
  * root complex integrated endpoint if @port is a root complex event collector)
  * set the flag indicating that it can signal run-time wake-up events via PCIe
  * PME interrupts.
  */
 static void pcie_pme_mark_devices(struct pci_dev *port)
 {
 	pcie_pme_set_native(port, NULL);
 	if (port->subordinate) {
 		pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
 	} else {
 		struct pci_bus *bus = port->bus;
 		struct pci_dev *dev;

 		/* Check if this is a root port event collector. */
 		if (pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC || !bus)
 			return;

 		down_read(&pci_bus_sem);
 		list_for_each_entry(dev, &bus->devices, bus_list)
 			if (pci_is_pcie(dev)
 			    && pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
 				pcie_pme_set_native(dev, NULL);
 		up_read(&pci_bus_sem);
 	}
 }

 /**
  * pcie_pme_probe - Initialize PCIe PME service for given root port.
  * @srv: PCIe service to initialize.
  */
 static int pcie_pme_probe(struct pcie_device *srv)
 {
 	struct pci_dev *port;
 	struct pcie_pme_service_data *data;
 	int ret;

 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	spin_lock_init(&data->lock);
 	INIT_WORK(&data->work, pcie_pme_work_fn);
 	data->srv = srv;
 	set_service_data(srv, data);

 	port = srv->port;
 	pcie_pme_interrupt_enable(port, false);
 	pcie_clear_root_pme_status(port);

 	ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
 	if (ret) {
 		kfree(data);
 	} else {
 		pcie_pme_mark_devices(port);
 		pcie_pme_interrupt_enable(port, true);
 	}

 	return ret;
 }

 static bool pcie_pme_check_wakeup(struct pci_bus *bus)
 {
 	struct pci_dev *dev;

 	if (!bus)
 		return false;

 	list_for_each_entry(dev, &bus->devices, bus_list)
 		if (device_may_wakeup(&dev->dev)
 		    || pcie_pme_check_wakeup(dev->subordinate))
 			return true;

 	return false;
 }

 /**
  * pcie_pme_suspend - Suspend PCIe PME service device.
  * @srv: PCIe service device to suspend.
  */
 static int pcie_pme_suspend(struct pcie_device *srv)
 {
 	struct pcie_pme_service_data *data = get_service_data(srv);
 	struct pci_dev *port = srv->port;
 	bool wakeup;

 	if (device_may_wakeup(&port->dev)) {
 		wakeup = true;
 	} else {
 		down_read(&pci_bus_sem);
 		wakeup = pcie_pme_check_wakeup(port->subordinate);
 		up_read(&pci_bus_sem);
 	}
 	spin_lock_irq(&data->lock);
 	if (wakeup) {
 		enable_irq_wake(srv->irq);
 		data->suspend_level = PME_SUSPEND_WAKEUP;
 	} else {
 		struct pci_dev *port = srv->port;

 		pcie_pme_interrupt_enable(port, false);
 		pcie_clear_root_pme_status(port);
 		data->suspend_level = PME_SUSPEND_NOIRQ;
 	}
 	spin_unlock_irq(&data->lock);

 	synchronize_irq(srv->irq);

 	return 0;
 }

 /**
  * pcie_pme_resume - Resume PCIe PME service device.
  * @srv - PCIe service device to resume.
  */
 static int pcie_pme_resume(struct pcie_device *srv)
 {
 	struct pcie_pme_service_data *data = get_service_data(srv);

 	spin_lock_irq(&data->lock);
 	if (data->suspend_level == PME_SUSPEND_NOIRQ) {
 		struct pci_dev *port = srv->port;

 		pcie_clear_root_pme_status(port);
 		pcie_pme_interrupt_enable(port, true);
 	} else {
 		disable_irq_wake(srv->irq);
 	}
 	data->suspend_level = PME_SUSPEND_NONE;
 	spin_unlock_irq(&data->lock);

 	return 0;
 }

 /**
  * pcie_pme_remove - Prepare PCIe PME service device for removal.
  * @srv - PCIe service device to remove.
  */
 static void pcie_pme_remove(struct pcie_device *srv)
 {
 	pcie_pme_suspend(srv);
 	free_irq(srv->irq, srv);
 	kfree(get_service_data(srv));
 }

 static struct pcie_port_service_driver pcie_pme_driver = {
 	.name		= "pcie_pme",
 	.port_type	= PCI_EXP_TYPE_ROOT_PORT,
 	.service	= PCIE_PORT_SERVICE_PME,

 	.probe		= pcie_pme_probe,
 	.suspend	= pcie_pme_suspend,
 	.resume		= pcie_pme_resume,
 	.remove		= pcie_pme_remove,
 };

 /**
  * pcie_pme_service_init - Register the PCIe PME service driver.
  */
 static int __init pcie_pme_service_init(void)
 {
 	return pcie_port_service_register(&pcie_pme_driver);
 }

 module_init(pcie_pme_service_init);
	/*
	* PCIe Native PME support
	*
	* Copyright (C) 2007 - 2009 Intel Corp
	* Copyright (C) 2007 - 2009 Shaohua Li <shaohua.li@intel.com>
	* Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License V2. See the file "COPYING" in the main directory of this archive
	* for more details.
	*/

	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/device.h>
	#include <linux/pcieport_if.h>
	#include <linux/pm_runtime.h>

	#include "../pci.h"
	#include "portdrv.h"

	/*
	* If this switch is set, MSI will not be used for PCIe PME signaling. This
	* causes the PCIe port driver to use INTx interrupts only, but it turns out
	* that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
	* wake-up from system sleep states.
	*/
	bool pcie_pme_msi_disabled;

	static int __init pcie_pme_setup(char *str)
	{
	if (!strncmp(str, "nomsi", 5))
	pcie_pme_msi_disabled = true;

	return 1;
	}
	__setup("pcie_pme=", pcie_pme_setup);

	enum pme_suspend_level {
	PME_SUSPEND_NONE = 0,
	PME_SUSPEND_WAKEUP,
	PME_SUSPEND_NOIRQ,
	};

	struct pcie_pme_service_data {
	spinlock_t lock;
	struct pcie_device *srv;
	struct work_struct work;
	enum pme_suspend_level suspend_level;
	};

	/**
	* pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
	* @dev: PCIe root port or event collector.
	* @enable: Enable or disable the interrupt.
	*/
	void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
	{
	if (enable)
	pcie_capability_set_word(dev, PCI_EXP_RTCTL,
	PCI_EXP_RTCTL_PMEIE);
	else
	pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
	PCI_EXP_RTCTL_PMEIE);
	}

	/**
	* pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
	* @bus: PCI bus to scan.
	*
	* Scan given PCI bus and all buses under it for devices asserting PME#.
	*/
	static bool pcie_pme_walk_bus(struct pci_bus *bus)
	{
	struct pci_dev *dev;
	bool ret = false;

	list_for_each_entry(dev, &bus->devices, bus_list) {
	/* Skip PCIe devices in case we started from a root port. */
	if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
	if (dev->pme_poll)
	dev->pme_poll = false;

	pci_wakeup_event(dev);
	pm_request_resume(&dev->dev);
	ret = true;
	}

	if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
	ret = true;
	}

	return ret;
	}

	/**
	* pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
	* @bus: Secondary bus of the bridge.
	* @devfn: Device/function number to check.
	*
	* PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
	* PCIe PME message. In such that case the bridge should use the Requester ID
	* of device/function number 0 on its secondary bus.
	*/
	static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
	{
	struct pci_dev *dev;
	bool found = false;

	if (devfn)
	return false;

	dev = pci_dev_get(bus->self);
	if (!dev)
	return false;

	if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
	down_read(&pci_bus_sem);
	if (pcie_pme_walk_bus(bus))
	found = true;
	up_read(&pci_bus_sem);
	}

	pci_dev_put(dev);
	return found;
	}

	/**
	* pcie_pme_handle_request - Find device that generated PME and handle it.
	* @port: Root port or event collector that generated the PME interrupt.
	* @req_id: PCIe Requester ID of the device that generated the PME.
	*/
	static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
	{
	u8 busnr = req_id >> 8, devfn = req_id & 0xff;
	struct pci_bus *bus;
	struct pci_dev *dev;
	bool found = false;

	/* First, check if the PME is from the root port itself. */
	if (port->devfn == devfn && port->bus->number == busnr) {
	if (port->pme_poll)
	port->pme_poll = false;

	if (pci_check_pme_status(port)) {
	pm_request_resume(&port->dev);
	found = true;
	} else {
	/*
	* Apparently, the root port generated the PME on behalf
	* of a non-PCIe device downstream. If this is done by
	* a root port, the Requester ID field in its status
	* register may contain either the root port's, or the
	* source device's information (PCI Express Base
	* Specification, Rev. 2.0, Section 6.1.9).
	*/
	down_read(&pci_bus_sem);
	found = pcie_pme_walk_bus(port->subordinate);
	up_read(&pci_bus_sem);
	}
	goto out;
	}

	/* Second, find the bus the source device is on. */
	bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
	if (!bus)
	goto out;

	/* Next, check if the PME is from a PCIe-PCI bridge. */
	found = pcie_pme_from_pci_bridge(bus, devfn);
	if (found)
	goto out;

	/* Finally, try to find the PME source on the bus. */
	down_read(&pci_bus_sem);
	list_for_each_entry(dev, &bus->devices, bus_list) {
	pci_dev_get(dev);
	if (dev->devfn == devfn) {
	found = true;
	break;
	}
	pci_dev_put(dev);
	}
	up_read(&pci_bus_sem);

	if (found) {
	/* The device is there, but we have to check its PME status. */
	found = pci_check_pme_status(dev);
	if (found) {
	if (dev->pme_poll)
	dev->pme_poll = false;

	pci_wakeup_event(dev);
	pm_request_resume(&dev->dev);
	}
	pci_dev_put(dev);
	} else if (devfn) {
	/*
	* The device is not there, but we can still try to recover by
	* assuming that the PME was reported by a PCIe-PCI bridge that
	* used devfn different from zero.
	*/
	dev_dbg(&port->dev, "PME interrupt generated for non-existent device %02x:%02x.%d\n",
	busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
	found = pcie_pme_from_pci_bridge(bus, 0);
	}

	out:
	if (!found)
	dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
	}

	/**
	* pcie_pme_work_fn - Work handler for PCIe PME interrupt.
	* @work: Work structure giving access to service data.
	*/
	static void pcie_pme_work_fn(struct work_struct *work)
	{
	struct pcie_pme_service_data *data =
	container_of(work, struct pcie_pme_service_data, work);
	struct pci_dev *port = data->srv->port;
	u32 rtsta;

	spin_lock_irq(&data->lock);

	for (;;) {
	if (data->suspend_level != PME_SUSPEND_NONE)
	break;

	pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
	if (rtsta & PCI_EXP_RTSTA_PME) {
	/*
	* Clear PME status of the port. If there are other
	* pending PMEs, the status will be set again.
	*/
	pcie_clear_root_pme_status(port);

	spin_unlock_irq(&data->lock);
	pcie_pme_handle_request(port, rtsta & 0xffff);
	spin_lock_irq(&data->lock);

	continue;
	}

	/* No need to loop if there are no more PMEs pending. */
	if (!(rtsta & PCI_EXP_RTSTA_PENDING))
	break;

	spin_unlock_irq(&data->lock);
	cpu_relax();
	spin_lock_irq(&data->lock);
	}

	if (data->suspend_level == PME_SUSPEND_NONE)
	pcie_pme_interrupt_enable(port, true);

	spin_unlock_irq(&data->lock);
	}

	/**
	* pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
	* @irq: Interrupt vector.
	* @context: Interrupt context pointer.
	*/
	static irqreturn_t pcie_pme_irq(int irq, void *context)
	{
	struct pci_dev *port;
	struct pcie_pme_service_data *data;
	u32 rtsta;
	unsigned long flags;

	port = ((struct pcie_device *)context)->port;
	data = get_service_data((struct pcie_device *)context);

	spin_lock_irqsave(&data->lock, flags);
	pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);

	if (!(rtsta & PCI_EXP_RTSTA_PME)) {
	spin_unlock_irqrestore(&data->lock, flags);
	return IRQ_NONE;
	}

	pcie_pme_interrupt_enable(port, false);
	spin_unlock_irqrestore(&data->lock, flags);

	/* We don't use pm_wq, because it's freezable. */
	schedule_work(&data->work);

	return IRQ_HANDLED;
	}

	/**
	* pcie_pme_set_native - Set the PME interrupt flag for given device.
	* @dev: PCI device to handle.
	* @ign: Ignored.
	*/
	static int pcie_pme_set_native(struct pci_dev dev, void ign)
	{
	dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");

	device_set_run_wake(&dev->dev, true);
	dev->pme_interrupt = true;
	return 0;
	}

	/**
	* pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
	* @port: PCIe root port or event collector to handle.
	*
	* For each device below given root port, including the port itself (or for each
	* root complex integrated endpoint if @port is a root complex event collector)
	* set the flag indicating that it can signal run-time wake-up events via PCIe
	* PME interrupts.
	*/
	static void pcie_pme_mark_devices(struct pci_dev *port)
	{
	pcie_pme_set_native(port, NULL);
	if (port->subordinate) {
	pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
	} else {
	struct pci_bus *bus = port->bus;
	struct pci_dev *dev;

	/* Check if this is a root port event collector. */
	if (pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC \|\| !bus)
	return;

	down_read(&pci_bus_sem);
	list_for_each_entry(dev, &bus->devices, bus_list)
	if (pci_is_pcie(dev)
	&& pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
	pcie_pme_set_native(dev, NULL);
	up_read(&pci_bus_sem);
	}
	}

	/**
	* pcie_pme_probe - Initialize PCIe PME service for given root port.
	* @srv: PCIe service to initialize.
	*/
	static int pcie_pme_probe(struct pcie_device *srv)
	{
	struct pci_dev *port;
	struct pcie_pme_service_data *data;
	int ret;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	spin_lock_init(&data->lock);
	INIT_WORK(&data->work, pcie_pme_work_fn);
	data->srv = srv;
	set_service_data(srv, data);

	port = srv->port;
	pcie_pme_interrupt_enable(port, false);
	pcie_clear_root_pme_status(port);

	ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
	if (ret) {
	kfree(data);
	} else {
	pcie_pme_mark_devices(port);
	pcie_pme_interrupt_enable(port, true);
	}

	return ret;
	}

	static bool pcie_pme_check_wakeup(struct pci_bus *bus)
	{
	struct pci_dev *dev;

	if (!bus)
	return false;

	list_for_each_entry(dev, &bus->devices, bus_list)
	if (device_may_wakeup(&dev->dev)
	\|\| pcie_pme_check_wakeup(dev->subordinate))
	return true;

	return false;
	}

	/**
	* pcie_pme_suspend - Suspend PCIe PME service device.
	* @srv: PCIe service device to suspend.
	*/
	static int pcie_pme_suspend(struct pcie_device *srv)
	{
	struct pcie_pme_service_data *data = get_service_data(srv);
	struct pci_dev *port = srv->port;
	bool wakeup;

	if (device_may_wakeup(&port->dev)) {
	wakeup = true;
	} else {
	down_read(&pci_bus_sem);
	wakeup = pcie_pme_check_wakeup(port->subordinate);
	up_read(&pci_bus_sem);
	}
	spin_lock_irq(&data->lock);
	if (wakeup) {
	enable_irq_wake(srv->irq);
	data->suspend_level = PME_SUSPEND_WAKEUP;
	} else {
	struct pci_dev *port = srv->port;

	pcie_pme_interrupt_enable(port, false);
	pcie_clear_root_pme_status(port);
	data->suspend_level = PME_SUSPEND_NOIRQ;
	}
	spin_unlock_irq(&data->lock);

	synchronize_irq(srv->irq);

	return 0;
	}

	/**
	* pcie_pme_resume - Resume PCIe PME service device.
	* @srv - PCIe service device to resume.
	*/
	static int pcie_pme_resume(struct pcie_device *srv)
	{
	struct pcie_pme_service_data *data = get_service_data(srv);

	spin_lock_irq(&data->lock);
	if (data->suspend_level == PME_SUSPEND_NOIRQ) {
	struct pci_dev *port = srv->port;

	pcie_clear_root_pme_status(port);
	pcie_pme_interrupt_enable(port, true);
	} else {
	disable_irq_wake(srv->irq);
	}
	data->suspend_level = PME_SUSPEND_NONE;
	spin_unlock_irq(&data->lock);

	return 0;
	}

	/**
	* pcie_pme_remove - Prepare PCIe PME service device for removal.
	* @srv - PCIe service device to remove.
	*/
	static void pcie_pme_remove(struct pcie_device *srv)
	{
	pcie_pme_suspend(srv);
	free_irq(srv->irq, srv);
	kfree(get_service_data(srv));
	}

	static struct pcie_port_service_driver pcie_pme_driver = {
	.name = "pcie_pme",
	.port_type = PCI_EXP_TYPE_ROOT_PORT,
	.service = PCIE_PORT_SERVICE_PME,

	.probe = pcie_pme_probe,
	.suspend = pcie_pme_suspend,
	.resume = pcie_pme_resume,
	.remove = pcie_pme_remove,
	};

	/**
	* pcie_pme_service_init - Register the PCIe PME service driver.
	*/
	static int __init pcie_pme_service_init(void)
	{
	return pcie_port_service_register(&pcie_pme_driver);
	}

	module_init(pcie_pme_service_init);