drivers/pci/pci-acpi.c - kernel/msm-4.9 - Gitiles

 /*
  * File:	pci-acpi.c
  * Purpose:	Provide PCI support in ACPI
  *
  * Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
  * Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
  * Copyright (C) 2004 Intel Corp.
  */

 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/module.h>
 #include <linux/pci-aspm.h>
 #include <acpi/acpi.h>
 #include <acpi/acpi_bus.h>

 #include <linux/pci-acpi.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_qos.h>
 #include "pci.h"

 /**
  * 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)
 		return;

 	if (pci_dev->current_state == PCI_D3cold) {
 		pci_wakeup_event(pci_dev);
 		pm_runtime_resume(&pci_dev->dev);
 		return;
 	}

 	if (!pci_dev->pm_cap || !pci_dev->pme_support
 	     || pci_check_pme_status(pci_dev)) {
 		if (pci_dev->pme_poll)
 			pci_dev->pme_poll = false;

 		pci_wakeup_event(pci_dev);
 		pm_runtime_resume(&pci_dev->dev);
 	}

 	if (pci_dev->subordinate)
 		pci_pme_wakeup_bus(pci_dev->subordinate);
 }

 /**
  * 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 acpi_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 acpi_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 acpi_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 acpi_remove_pm_notifier(dev, pci_acpi_wake_dev);
 }

 phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
 {
 	acpi_status status = AE_NOT_EXIST;
 	unsigned long long mcfg_addr;

 	if (handle)
 		status = acpi_evaluate_integer(handle, METHOD_NAME__CBA,
 					       NULL, &mcfg_addr);
 	if (ACPI_FAILURE(status))
 		return 0;

 	return (phys_addr_t)mcfg_addr;
 }

 /*
  * _SxD returns the D-state with the highest power
  * (lowest D-state number) supported in the S-state "x".
  *
  * If the devices does not have a _PRW
  * (Power Resources for Wake) supporting system wakeup from "x"
  * then the OS is free to choose a lower power (higher number
  * D-state) than the return value from _SxD.
  *
  * But if _PRW is enabled at S-state "x", the OS
  * must not choose a power lower than _SxD --
  * unless the device has an _SxW method specifying
  * the lowest power (highest D-state number) the device
  * may enter while still able to wake the system.
  *
  * ie. depending on global OS policy:
  *
  * if (_PRW at S-state x)
  *	choose from highest power _SxD to lowest power _SxW
  * else // no _PRW at S-state x
  * 	choose highest power _SxD or any lower power
  */

 static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
 {
 	int acpi_state, d_max;

 	if (pdev->no_d3cold)
 		d_max = ACPI_STATE_D3_HOT;
 	else
 		d_max = ACPI_STATE_D3_COLD;
 	acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL, d_max);
 	if (acpi_state < 0)
 		return PCI_POWER_ERROR;

 	switch (acpi_state) {
 	case ACPI_STATE_D0:
 		return PCI_D0;
 	case ACPI_STATE_D1:
 		return PCI_D1;
 	case ACPI_STATE_D2:
 		return PCI_D2;
 	case ACPI_STATE_D3_HOT:
 		return PCI_D3hot;
 	case ACPI_STATE_D3_COLD:
 		return PCI_D3cold;
 	}
 	return PCI_POWER_ERROR;
 }

 static bool acpi_pci_power_manageable(struct pci_dev *dev)
 {
 	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);

 	return handle ? acpi_bus_power_manageable(handle) : false;
 }

 static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
 	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
 	acpi_handle tmp;
 	static const u8 state_conv[] = {
 		[PCI_D0] = ACPI_STATE_D0,
 		[PCI_D1] = ACPI_STATE_D1,
 		[PCI_D2] = ACPI_STATE_D2,
 		[PCI_D3hot] = ACPI_STATE_D3,
 		[PCI_D3cold] = ACPI_STATE_D3
 	};
 	int error = -EINVAL;

 	/* If the ACPI device has _EJ0, ignore the device */
 	if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
 		return -ENODEV;

 	switch (state) {
 	case PCI_D3cold:
 		if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
 				PM_QOS_FLAGS_ALL) {
 			error = -EBUSY;
 			break;
 		}
 	case PCI_D0:
 	case PCI_D1:
 	case PCI_D2:
 	case PCI_D3hot:
 		error = acpi_bus_set_power(handle, state_conv[state]);
 	}

 	if (!error)
 		dev_info(&dev->dev, "power state changed by ACPI to %s\n",
 			 pci_power_name(state));

 	return error;
 }

 static bool acpi_pci_can_wakeup(struct pci_dev *dev)
 {
 	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);

 	return handle ? acpi_bus_can_wakeup(handle) : false;
 }

 static void acpi_pci_propagate_wakeup_enable(struct pci_bus *bus, bool enable)
 {
 	while (bus->parent) {
 		if (!acpi_pm_device_sleep_wake(&bus->self->dev, enable))
 			return;
 		bus = bus->parent;
 	}

 	/* We have reached the root bus. */
 	if (bus->bridge)
 		acpi_pm_device_sleep_wake(bus->bridge, enable);
 }

 static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
 {
 	if (acpi_pci_can_wakeup(dev))
 		return acpi_pm_device_sleep_wake(&dev->dev, enable);

 	acpi_pci_propagate_wakeup_enable(dev->bus, enable);
 	return 0;
 }

 static void acpi_pci_propagate_run_wake(struct pci_bus *bus, bool enable)
 {
 	while (bus->parent) {
 		struct pci_dev *bridge = bus->self;

 		if (bridge->pme_interrupt)
 			return;
 		if (!acpi_pm_device_run_wake(&bridge->dev, enable))
 			return;
 		bus = bus->parent;
 	}

 	/* We have reached the root bus. */
 	if (bus->bridge)
 		acpi_pm_device_run_wake(bus->bridge, enable);
 }

 static int acpi_pci_run_wake(struct pci_dev *dev, bool enable)
 {
 	/*
 	 * Per PCI Express Base Specification Revision 2.0 section
 	 * 5.3.3.2 Link Wakeup, platform support is needed for D3cold
 	 * waking up to power on the main link even if there is PME
 	 * support for D3cold
 	 */
 	if (dev->pme_interrupt && !dev->runtime_d3cold)
 		return 0;

 	if (!acpi_pm_device_run_wake(&dev->dev, enable))
 		return 0;

 	acpi_pci_propagate_run_wake(dev->bus, enable);
 	return 0;
 }

 static 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,
 	.sleep_wake = acpi_pci_sleep_wake,
 	.run_wake = acpi_pci_run_wake,
 };

 /* ACPI bus type */
 static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
 {
 	struct pci_dev * pci_dev;
 	u64	addr;

 	pci_dev = to_pci_dev(dev);
 	/* Please ref to ACPI spec for the syntax of _ADR */
 	addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
 	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
 	if (!*handle)
 		return -ENODEV;
 	return 0;
 }

 static int acpi_pci_find_root_bridge(struct device *dev, acpi_handle *handle)
 {
 	int num;
 	unsigned int seg, bus;

 	/*
 	 * The string should be the same as root bridge's name
 	 * Please look at 'pci_scan_bus_parented'
 	 */
 	num = sscanf(dev_name(dev), "pci%04x:%02x", &seg, &bus);
 	if (num != 2)
 		return -ENODEV;
 	*handle = acpi_get_pci_rootbridge_handle(seg, bus);
 	if (!*handle)
 		return -ENODEV;
 	return 0;
 }

 static void pci_acpi_setup(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	acpi_handle handle = ACPI_HANDLE(dev);
 	struct acpi_device *adev;
 	acpi_status status;
 	acpi_handle dummy;

 	/*
 	 * Evaluate and parse _PRT, if exists.  This code allows parsing of
 	 * _PRT objects within the scope of non-bridge devices.  Note that
 	 * _PRTs within the scope of a PCI bridge assume the bridge's
 	 * subordinate bus number.
 	 *
 	 * TBD: Can _PRTs exist within the scope of non-bridge PCI devices?
 	 */
 	status = acpi_get_handle(handle, METHOD_NAME__PRT, &dummy);
 	if (ACPI_SUCCESS(status)) {
 		unsigned char bus;

 		bus = pci_dev->subordinate ?
 			pci_dev->subordinate->number : pci_dev->bus->number;
 		acpi_pci_irq_add_prt(handle, pci_domain_nr(pci_dev->bus), bus);
 	}

 	if (acpi_bus_get_device(handle, &adev) || !adev->wakeup.flags.valid)
 		return;

 	device_set_wakeup_capable(dev, true);
 	acpi_pci_sleep_wake(pci_dev, false);

 	pci_acpi_add_pm_notifier(adev, pci_dev);
 	if (adev->wakeup.flags.run_wake)
 		device_set_run_wake(dev, true);
 }

 static void pci_acpi_cleanup(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	acpi_handle handle = ACPI_HANDLE(dev);
 	struct acpi_device *adev;

 	if (!acpi_bus_get_device(handle, &adev) && adev->wakeup.flags.valid) {
 		device_set_wakeup_capable(dev, false);
 		device_set_run_wake(dev, false);
 		pci_acpi_remove_pm_notifier(adev);
 	}

 	if (pci_dev->subordinate)
 		acpi_pci_irq_del_prt(pci_domain_nr(pci_dev->bus),
 				     pci_dev->subordinate->number);
 }

 static struct acpi_bus_type acpi_pci_bus = {
 	.bus = &pci_bus_type,
 	.find_device = acpi_pci_find_device,
 	.find_bridge = acpi_pci_find_root_bridge,
 	.setup = pci_acpi_setup,
 	.cleanup = pci_acpi_cleanup,
 };

 static int __init acpi_pci_init(void)
 {
 	int ret;

 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
 		printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it\n");
 		pci_no_msi();
 	}

 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
 		printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
 		pcie_no_aspm();
 	}

 	ret = register_acpi_bus_type(&acpi_pci_bus);
 	if (ret)
 		return 0;
 	pci_set_platform_pm(&acpi_pci_platform_pm);
 	return 0;
 }
 arch_initcall(acpi_pci_init);
	/*
	* File: pci-acpi.c
	* Purpose: Provide PCI support in ACPI
	*
	* Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
	* Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
	* Copyright (C) 2004 Intel Corp.
	*/

	#include <linux/delay.h>
	#include <linux/init.h>
	#include <linux/pci.h>
	#include <linux/module.h>
	#include <linux/pci-aspm.h>
	#include <acpi/acpi.h>
	#include <acpi/acpi_bus.h>

	#include <linux/pci-acpi.h>
	#include <linux/pm_runtime.h>
	#include <linux/pm_qos.h>
	#include "pci.h"

	/**
	* 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)
	return;

	if (pci_dev->current_state == PCI_D3cold) {
	pci_wakeup_event(pci_dev);
	pm_runtime_resume(&pci_dev->dev);
	return;
	}

	if (!pci_dev->pm_cap \|\| !pci_dev->pme_support
	\|\| pci_check_pme_status(pci_dev)) {
	if (pci_dev->pme_poll)
	pci_dev->pme_poll = false;

	pci_wakeup_event(pci_dev);
	pm_runtime_resume(&pci_dev->dev);
	}

	if (pci_dev->subordinate)
	pci_pme_wakeup_bus(pci_dev->subordinate);
	}

	/**
	* 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 acpi_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 acpi_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 acpi_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 acpi_remove_pm_notifier(dev, pci_acpi_wake_dev);
	}

	phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
	{
	acpi_status status = AE_NOT_EXIST;
	unsigned long long mcfg_addr;

	if (handle)
	status = acpi_evaluate_integer(handle, METHOD_NAME__CBA,
	NULL, &mcfg_addr);
	if (ACPI_FAILURE(status))
	return 0;

	return (phys_addr_t)mcfg_addr;
	}

	/*
	* _SxD returns the D-state with the highest power
	* (lowest D-state number) supported in the S-state "x".
	*
	* If the devices does not have a _PRW
	* (Power Resources for Wake) supporting system wakeup from "x"
	* then the OS is free to choose a lower power (higher number
	* D-state) than the return value from _SxD.
	*
	* But if _PRW is enabled at S-state "x", the OS
	* must not choose a power lower than _SxD --
	* unless the device has an _SxW method specifying
	* the lowest power (highest D-state number) the device
	* may enter while still able to wake the system.
	*
	* ie. depending on global OS policy:
	*
	* if (_PRW at S-state x)
	* choose from highest power _SxD to lowest power _SxW
	* else // no _PRW at S-state x
	* choose highest power _SxD or any lower power
	*/

	static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
	{
	int acpi_state, d_max;

	if (pdev->no_d3cold)
	d_max = ACPI_STATE_D3_HOT;
	else
	d_max = ACPI_STATE_D3_COLD;
	acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL, d_max);
	if (acpi_state < 0)
	return PCI_POWER_ERROR;

	switch (acpi_state) {
	case ACPI_STATE_D0:
	return PCI_D0;
	case ACPI_STATE_D1:
	return PCI_D1;
	case ACPI_STATE_D2:
	return PCI_D2;
	case ACPI_STATE_D3_HOT:
	return PCI_D3hot;
	case ACPI_STATE_D3_COLD:
	return PCI_D3cold;
	}
	return PCI_POWER_ERROR;
	}

	static bool acpi_pci_power_manageable(struct pci_dev *dev)
	{
	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);

	return handle ? acpi_bus_power_manageable(handle) : false;
	}

	static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
	{
	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
	acpi_handle tmp;
	static const u8 state_conv[] = {
	[PCI_D0] = ACPI_STATE_D0,
	[PCI_D1] = ACPI_STATE_D1,
	[PCI_D2] = ACPI_STATE_D2,
	[PCI_D3hot] = ACPI_STATE_D3,
	[PCI_D3cold] = ACPI_STATE_D3
	};
	int error = -EINVAL;

	/* If the ACPI device has _EJ0, ignore the device */
	if (!handle \|\| ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
	return -ENODEV;

	switch (state) {
	case PCI_D3cold:
	if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
	PM_QOS_FLAGS_ALL) {
	error = -EBUSY;
	break;
	}
	case PCI_D0:
	case PCI_D1:
	case PCI_D2:
	case PCI_D3hot:
	error = acpi_bus_set_power(handle, state_conv[state]);
	}

	if (!error)
	dev_info(&dev->dev, "power state changed by ACPI to %s\n",
	pci_power_name(state));

	return error;
	}

	static bool acpi_pci_can_wakeup(struct pci_dev *dev)
	{
	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);

	return handle ? acpi_bus_can_wakeup(handle) : false;
	}

	static void acpi_pci_propagate_wakeup_enable(struct pci_bus *bus, bool enable)
	{
	while (bus->parent) {
	if (!acpi_pm_device_sleep_wake(&bus->self->dev, enable))
	return;
	bus = bus->parent;
	}

	/* We have reached the root bus. */
	if (bus->bridge)
	acpi_pm_device_sleep_wake(bus->bridge, enable);
	}

	static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
	{
	if (acpi_pci_can_wakeup(dev))
	return acpi_pm_device_sleep_wake(&dev->dev, enable);

	acpi_pci_propagate_wakeup_enable(dev->bus, enable);
	return 0;
	}

	static void acpi_pci_propagate_run_wake(struct pci_bus *bus, bool enable)
	{
	while (bus->parent) {
	struct pci_dev *bridge = bus->self;

	if (bridge->pme_interrupt)
	return;
	if (!acpi_pm_device_run_wake(&bridge->dev, enable))
	return;
	bus = bus->parent;
	}

	/* We have reached the root bus. */
	if (bus->bridge)
	acpi_pm_device_run_wake(bus->bridge, enable);
	}

	static int acpi_pci_run_wake(struct pci_dev *dev, bool enable)
	{
	/*
	* Per PCI Express Base Specification Revision 2.0 section
	* 5.3.3.2 Link Wakeup, platform support is needed for D3cold
	* waking up to power on the main link even if there is PME
	* support for D3cold
	*/
	if (dev->pme_interrupt && !dev->runtime_d3cold)
	return 0;

	if (!acpi_pm_device_run_wake(&dev->dev, enable))
	return 0;

	acpi_pci_propagate_run_wake(dev->bus, enable);
	return 0;
	}

	static 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,
	.sleep_wake = acpi_pci_sleep_wake,
	.run_wake = acpi_pci_run_wake,
	};

	/* ACPI bus type */
	static int acpi_pci_find_device(struct device dev, acpi_handle handle)
	{
	struct pci_dev * pci_dev;
	u64 addr;

	pci_dev = to_pci_dev(dev);
	/* Please ref to ACPI spec for the syntax of _ADR */
	addr = (PCI_SLOT(pci_dev->devfn) << 16) \| PCI_FUNC(pci_dev->devfn);
	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
	if (!*handle)
	return -ENODEV;
	return 0;
	}

	static int acpi_pci_find_root_bridge(struct device dev, acpi_handle handle)
	{
	int num;
	unsigned int seg, bus;

	/*
	* The string should be the same as root bridge's name
	* Please look at 'pci_scan_bus_parented'
	*/
	num = sscanf(dev_name(dev), "pci%04x:%02x", &seg, &bus);
	if (num != 2)
	return -ENODEV;
	*handle = acpi_get_pci_rootbridge_handle(seg, bus);
	if (!*handle)
	return -ENODEV;
	return 0;
	}

	static void pci_acpi_setup(struct device *dev)
	{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	acpi_handle handle = ACPI_HANDLE(dev);
	struct acpi_device *adev;
	acpi_status status;
	acpi_handle dummy;

	/*
	* Evaluate and parse _PRT, if exists. This code allows parsing of
	* _PRT objects within the scope of non-bridge devices. Note that
	* _PRTs within the scope of a PCI bridge assume the bridge's
	* subordinate bus number.
	*
	* TBD: Can _PRTs exist within the scope of non-bridge PCI devices?
	*/
	status = acpi_get_handle(handle, METHOD_NAME__PRT, &dummy);
	if (ACPI_SUCCESS(status)) {
	unsigned char bus;

	bus = pci_dev->subordinate ?
	pci_dev->subordinate->number : pci_dev->bus->number;
	acpi_pci_irq_add_prt(handle, pci_domain_nr(pci_dev->bus), bus);
	}

	if (acpi_bus_get_device(handle, &adev) \|\| !adev->wakeup.flags.valid)
	return;

	device_set_wakeup_capable(dev, true);
	acpi_pci_sleep_wake(pci_dev, false);

	pci_acpi_add_pm_notifier(adev, pci_dev);
	if (adev->wakeup.flags.run_wake)
	device_set_run_wake(dev, true);
	}

	static void pci_acpi_cleanup(struct device *dev)
	{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	acpi_handle handle = ACPI_HANDLE(dev);
	struct acpi_device *adev;

	if (!acpi_bus_get_device(handle, &adev) && adev->wakeup.flags.valid) {
	device_set_wakeup_capable(dev, false);
	device_set_run_wake(dev, false);
	pci_acpi_remove_pm_notifier(adev);
	}

	if (pci_dev->subordinate)
	acpi_pci_irq_del_prt(pci_domain_nr(pci_dev->bus),
	pci_dev->subordinate->number);
	}

	static struct acpi_bus_type acpi_pci_bus = {
	.bus = &pci_bus_type,
	.find_device = acpi_pci_find_device,
	.find_bridge = acpi_pci_find_root_bridge,
	.setup = pci_acpi_setup,
	.cleanup = pci_acpi_cleanup,
	};

	static int __init acpi_pci_init(void)
	{
	int ret;

	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
	printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it\n");
	pci_no_msi();
	}

	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
	printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
	pcie_no_aspm();
	}

	ret = register_acpi_bus_type(&acpi_pci_bus);
	if (ret)
	return 0;
	pci_set_platform_pm(&acpi_pci_platform_pm);
	return 0;
	}
	arch_initcall(acpi_pci_init);