text: // SPDX-License-Identifier: GPL-2.0
  /*
   * (C) Copyright 2002-2004, 2007 Greg Kroah-Hartman <greg@kroah.com>
   * (C) Copyright 2007 Novell Inc.
   */
  
  #include <linux/pci.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/mempolicy.h>
  #include <linux/string.h>
  #include <linux/slab.h>
  #include <linux/sched.h>
  #include <linux/cpu.h>
  #include <linux/pm_runtime.h>
  #include <linux/suspend.h>
  #include <linux/kexec.h>
  #include <linux/of_device.h>
  #include <linux/acpi.h>
  #include "pci.h"
  #include "pcie/portdrv.h"
  
  struct pci_dynid {
  	struct list_head node;
  	struct pci_device_id id;
  };
  
  /**
   * pci_add_dynid - add a new PCI device ID to this driver and re-probe devices
   * @drv: target pci driver
   * @vendor: PCI vendor ID
   * @device: PCI device ID
   * @subvendor: PCI subvendor ID
   * @subdevice: PCI subdevice ID
   * @class: PCI class
   * @class_mask: PCI class mask
   * @driver_data: private driver data
   *
   * Adds a new dynamic pci device ID to this driver and causes the
   * driver to probe for all devices again.  @drv must have been
   * registered prior to calling this function.
   *
   * CONTEXT:
   * Does GFP_KERNEL allocation.
   *
   * RETURNS:
   * 0 on success, -errno on failure.
   */
  int pci_add_dynid(struct pci_driver *drv,
  		  unsigned int vendor, unsigned int device,
  		  unsigned int subvendor, unsigned int subdevice,
  		  unsigned int class, unsigned int class_mask,
  		  unsigned long driver_data)
  {
  	struct pci_dynid *dynid;
  
  	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
  	if (!dynid)
  		return -ENOMEM;
  
  	dynid->id.vendor = vendor;
  	dynid->id.device = device;
  	dynid->id.subvendor = subvendor;
  	dynid->id.subdevice = subdevice;
  	dynid->id.class = class;
  	dynid->id.class_mask = class_mask;
  	dynid->id.driver_data = driver_data;
  
  	spin_lock(&drv->dynids.lock);
  	list_add_tail(&dynid->node, &drv->dynids.list);
  	spin_unlock(&drv->dynids.lock);
  
  	return driver_attach(&drv->driver);
  }
  EXPORT_SYMBOL_GPL(pci_add_dynid);
  
  static void pci_free_dynids(struct pci_driver *drv)
  {
  	struct pci_dynid *dynid, *n;
  
  	spin_lock(&drv->dynids.lock);
  	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
  		list_del(&dynid->node);
  		kfree(dynid);
  	}
  	spin_unlock(&drv->dynids.lock);
  }
  
  /**
   * store_new_id - sysfs frontend to pci_add_dynid()
   * @driver: target device driver
   * @buf: buffer for scanning device ID data
   * @count: input size
   *
   * Allow PCI IDs to be added to an existing driver via sysfs.
   */
  static ssize_t new_id_store(struct device_driver *driver, const char *buf,
  			    size_t count)
  {
  	struct pci_driver *pdrv = to_pci_driver(driver);
  	const struct pci_device_id *ids = pdrv->id_table;
  	u32 vendor, device, subvendor = PCI_ANY_ID,
  		subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
  	unsigned long driver_data = 0;
  	int fields = 0;
  	int retval = 0;
  
  	fields = sscanf(buf, "%x %x %x %x %x %x %lx",
  			&vendor, &device, &subvendor, &subdevice,
  			&class, &class_mask, &driver_data);
  	if (fields < 2)
  		return -EINVAL;
  
  	if (fields != 7) {
  		struct pci_dev *pdev = kzalloc(sizeof(*pdev), GFP_KERNEL);
  		if (!pdev)
  			return -ENOMEM;
  
  		pdev->vendor = vendor;
  		pdev->device = device;
  		pdev->subsystem_vendor = subvendor;
  		pdev->subsystem_device = subdevice;
  		pdev->class = class;
  
  		if (pci_match_id(pdrv->id_table, pdev))
  			retval = -EEXIST;
  
  		kfree(pdev);
  
  		if (retval)
  			return retval;
  	}
  
  	/* Only accept driver_data values that match an existing id_table
  	   entry */
  	if (ids) {
  		retval = -EINVAL;
  		while (ids->vendor || ids->subvendor || ids->class_mask) {
  			if (driver_data == ids->driver_data) {
  				retval = 0;
  				break;
  			}
  			ids++;
  		}
  		if (retval)	/* No match */
  			return retval;
  	}
  
  	retval = pci_add_dynid(pdrv, vendor, device, subvendor, subdevice,
  			       class, class_mask, driver_data);
  	if (retval)
  		return retval;
  	return count;
  }
  static DRIVER_ATTR_WO(new_id);
  
  /**
   * store_remove_id - remove a PCI device ID from this driver
   * @driver: target device driver
   * @buf: buffer for scanning device ID data
   * @count: input size
   *
   * Removes a dynamic pci device ID to this driver.
   */
  static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
  			       size_t count)
  {
  	struct pci_dynid *dynid, *n;
  	struct pci_driver *pdrv = to_pci_driver(driver);
  	u32 vendor, device, subvendor = PCI_ANY_ID,
  		subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
  	int fields = 0;
  	size_t retval = -ENODEV;
  
  	fields = sscanf(buf, "%x %x %x %x %x %x",
  			&vendor, &device, &subvendor, &subdevice,
  			&class, &class_mask);
  	if (fields < 2)
  		return -EINVAL;
  
  	spin_lock(&pdrv->dynids.lock);
  	list_for_each_entry_safe(dynid, n, &pdrv->dynids.list, node) {
  		struct pci_device_id *id = &dynid->id;
  		if ((id->vendor == vendor) &&
  		    (id->device == device) &&
  		    (subvendor == PCI_ANY_ID || id->subvendor == subvendor) &&
  		    (subdevice == PCI_ANY_ID || id->subdevice == subdevice) &&
  		    !((id->class ^ class) & class_mask)) {
  			list_del(&dynid->node);
  			kfree(dynid);
  			retval = count;
  			break;
  		}
  	}
  	spin_unlock(&pdrv->dynids.lock);
  
  	return retval;
  }
  static DRIVER_ATTR_WO(remove_id);
  
  static struct attribute *pci_drv_attrs[] = {
  	&driver_attr_new_id.attr,
  	&driver_attr_remove_id.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(pci_drv);
  
  /**
   * pci_match_id - See if a pci device matches a given pci_id table
   * @ids: array of PCI device id structures to search in
   * @dev: the PCI device structure to match against.
   *
   * Used by a driver to check whether a PCI device present in the
   * system is in its list of supported devices.  Returns the matching
   * pci_device_id structure or %NULL if there is no match.
   *
   * Deprecated, don't use this as it will not catch any dynamic ids
   * that a driver might want to check for.
   */
  const struct pci_device_id *pci_match_id(const struct pci_device_id *ids,
  					 struct pci_dev *dev)
  {
  	if (ids) {
  		while (ids->vendor || ids->subvendor || ids->class_mask) {
  			if (pci_match_one_device(ids, dev))
  				return ids;
  			ids++;
  		}
  	}
  	return NULL;
  }
  EXPORT_SYMBOL(pci_match_id);
  
  static const struct pci_device_id pci_device_id_any = {
  	.vendor = PCI_ANY_ID,
  	.device = PCI_ANY_ID,
  	.subvendor = PCI_ANY_ID,
  	.subdevice = PCI_ANY_ID,
  };
  
  /**
   * pci_match_device - Tell if a PCI device structure has a matching PCI device id structure
   * @drv: the PCI driver to match against
   * @dev: the PCI device structure to match against
   *
   * Used by a driver to check whether a PCI device present in the
   * system is in its list of supported devices.  Returns the matching
   * pci_device_id structure or %NULL if there is no match.
   */
  static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
  						    struct pci_dev *dev)
  {
  	struct pci_dynid *dynid;
  	const struct pci_device_id *found_id = NULL;
  
  	/* When driver_override is set, only bind to the matching driver */
  	if (dev->driver_override && strcmp(dev->driver_override, drv->name))
  		return NULL;
  
  	/* Look at the dynamic ids first, before the static ones */
  	spin_lock(&drv->dynids.lock);
  	list_for_each_entry(dynid, &drv->dynids.list, node) {
  		if (pci_match_one_device(&dynid->id, dev)) {
  			found_id = &dynid->id;
  			break;
  		}
  	}
  	spin_unlock(&drv->dynids.lock);
  
  	if (!found_id)
  		found_id = pci_match_id(drv->id_table, dev);
  
  	/* driver_override will always match, send a dummy id */
  	if (!found_id && dev->driver_override)
  		found_id = &pci_device_id_any;
  
  	return found_id;
  }
  
  struct drv_dev_and_id {
  	struct pci_driver *drv;
  	struct pci_dev *dev;
  	const struct pci_device_id *id;
  };
  
  static long local_pci_probe(void *_ddi)
  {
  	struct drv_dev_and_id *ddi = _ddi;
  	struct pci_dev *pci_dev = ddi->dev;
  	struct pci_driver *pci_drv = ddi->drv;
  	struct device *dev = &pci_dev->dev;
  	int rc;
  
  	/*
  	 * Unbound PCI devices are always put in D0, regardless of
  	 * runtime PM status.  During probe, the device is set to
  	 * active and the usage count is incremented.  If the driver
  	 * supports runtime PM, it should call pm_runtime_put_noidle(),
  	 * or any other runtime PM helper function decrementing the usage
  	 * count, in its probe routine and pm_runtime_get_noresume() in
  	 * its remove routine.
  	 */
  	pm_runtime_get_sync(dev);
  	pci_dev->driver = pci_drv;
  	rc = pci_drv->probe(pci_dev, ddi->id);
  	if (!rc)
  		return rc;
  	if (rc < 0) {
  		pci_dev->driver = NULL;
  		pm_runtime_put_sync(dev);
  		return rc;
  	}
  	/*
  	 * Probe function should return < 0 for failure, 0 for success
  	 * Treat values > 0 as success, but warn.
  	 */
  	dev_warn(dev, "Driver probe function unexpectedly returned %d\n", rc);
  	return 0;
  }
  
  static bool pci_physfn_is_probed(struct pci_dev *dev)
  {
  #ifdef CONFIG_PCI_IOV
  	return dev->is_virtfn && dev->physfn->is_probed;
  #else
  	return false;
  #endif
  }
  
  static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
  			  const struct pci_device_id *id)
  {
  	int error, node, cpu;
  	struct drv_dev_and_id ddi = { drv, dev, id };
  
  	/*
  	 * Execute driver initialization on node where the device is
  	 * attached.  This way the driver likely allocates its local memory
  	 * on the right node.
  	 */
  	node = dev_to_node(&dev->dev);
  	dev->is_probed = 1;
  
  	cpu_hotplug_disable();
  
  	/*
  	 * Prevent nesting work_on_cpu() for the case where a Virtual Function
  	 * device is probed from work_on_cpu() of the Physical device.
  	 */
  	if (node < 0 || node >= MAX_NUMNODES || !node_online(node) ||
  	    pci_physfn_is_probed(dev))
  		cpu = nr_cpu_ids;
  	else
  		cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
  
  	if (cpu < nr_cpu_ids)
  		error = work_on_cpu(cpu, local_pci_probe, &ddi);
  	else
  		error = local_pci_probe(&ddi);
  
  	dev->is_probed = 0;
  	cpu_hotplug_enable();
  	return error;
  }
  
  /**
   * __pci_device_probe - check if a driver wants to claim a specific PCI device
   * @drv: driver to call to check if it wants the PCI device
   * @pci_dev: PCI device being probed
   *
   * returns 0 on success, else error.
   * side-effect: pci_dev->driver is set to drv when drv claims pci_dev.
   */
  static int __pci_device_probe(struct pci_driver *drv, struct pci_dev *pci_dev)
  {
  	const struct pci_device_id *id;
  	int error = 0;
  
  	if (!pci_dev->driver && drv->probe) {
  		error = -ENODEV;
  
  		id = pci_match_device(drv, pci_dev);
  		if (id)
  			error = pci_call_probe(drv, pci_dev, id);
  	}
  	return error;
  }
  
  int __weak pcibios_alloc_irq(struct pci_dev *dev)
  {
  	return 0;
  }
  
  void __weak pcibios_free_irq(struct pci_dev *dev)
  {
  }
  
  #ifdef CONFIG_PCI_IOV
  static inline bool pci_device_can_probe(struct pci_dev *pdev)
  {
  	return (!pdev->is_virtfn || pdev->physfn->sriov->drivers_autoprobe ||
  		pdev->driver_override);
  }
  #else
  static inline bool pci_device_can_probe(struct pci_dev *pdev)
  {
  	return true;
  }
  #endif
  
  static int pci_device_probe(struct device *dev)
  {
  	int error;
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = to_pci_driver(dev->driver);
  
  	if (!pci_device_can_probe(pci_dev))
  		return -ENODEV;
  
  	pci_assign_irq(pci_dev);
  
  	error = pcibios_alloc_irq(pci_dev);
  	if (error < 0)
  		return error;
  
  	pci_dev_get(pci_dev);
  	error = __pci_device_probe(drv, pci_dev);
  	if (error) {
  		pcibios_free_irq(pci_dev);
  		pci_dev_put(pci_dev);
  	}
  
  	return error;
  }
  
  static int pci_device_remove(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = pci_dev->driver;
  
  	if (drv) {
  		if (drv->remove) {
  			pm_runtime_get_sync(dev);
  			drv->remove(pci_dev);
  			pm_runtime_put_noidle(dev);
  		}
  		pcibios_free_irq(pci_dev);
  		pci_dev->driver = NULL;
  		pci_iov_remove(pci_dev);
  	}
  
  	/* Undo the runtime PM settings in local_pci_probe() */
  	pm_runtime_put_sync(dev);
  
  	/*
  	 * If the device is still on, set the power state as "unknown",
  	 * since it might change by the next time we load the driver.
  	 */
  	if (pci_dev->current_state == PCI_D0)
  		pci_dev->current_state = PCI_UNKNOWN;
  
  	/*
  	 * We would love to complain here if pci_dev->is_enabled is set, that
  	 * the driver should have called pci_disable_device(), but the
  	 * unfortunate fact is there are too many odd BIOS and bridge setups
  	 * that don't like drivers doing that all of the time.
  	 * Oh well, we can dream of sane hardware when we sleep, no matter how
  	 * horrible the crap we have to deal with is when we are awake...
  	 */
  
  	pci_dev_put(pci_dev);
  	return 0;
  }
  
  static void pci_device_shutdown(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = pci_dev->driver;
  
  	pm_runtime_resume(dev);
  
  	if (drv && drv->shutdown)
  		drv->shutdown(pci_dev);
  
  	/*
  	 * If this is a kexec reboot, turn off Bus Master bit on the
  	 * device to tell it to not continue to do DMA. Don't touch
  	 * devices in D3cold or unknown states.
  	 * If it is not a kexec reboot, firmware will hit the PCI
  	 * devices with big hammer and stop their DMA any way.
  	 */
  	if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
  		pci_clear_master(pci_dev);
  }
  
  #ifdef CONFIG_PM
  
  /* Auxiliary functions used for system resume and run-time resume. */
  
  /**
   * pci_restore_standard_config - restore standard config registers of PCI device
   * @pci_dev: PCI device to handle
   */
  static int pci_restore_standard_config(struct pci_dev *pci_dev)
  {
  	pci_update_current_state(pci_dev, PCI_UNKNOWN);
  
  	if (pci_dev->current_state != PCI_D0) {
  		int error = pci_set_power_state(pci_dev, PCI_D0);
  		if (error)
  			return error;
  	}
  
  	pci_restore_state(pci_dev);
  	pci_pme_restore(pci_dev);
  	return 0;
  }
  
  #endif
  
  #ifdef CONFIG_PM_SLEEP
  
  static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
  {
  	pci_power_up(pci_dev);
  	pci_restore_state(pci_dev);
  	pci_pme_restore(pci_dev);
  }
  
  /*
   * Default "suspend" method for devices that have no driver provided suspend,
   * or not even a driver at all (second part).
   */
  static void pci_pm_set_unknown_state(struct pci_dev *pci_dev)
  {
  	/*
  	 * mark its power state as "unknown", since we don't know if
  	 * e.g. the BIOS will change its device state when we suspend.
  	 */
  	if (pci_dev->current_state == PCI_D0)
  		pci_dev->current_state = PCI_UNKNOWN;
  }
  
  /*
   * Default "resume" method for devices that have no driver provided resume,
   * or not even a driver at all (second part).
   */
  static int pci_pm_reenable_device(struct pci_dev *pci_dev)
  {
  	int retval;
  
  	/* if the device was enabled before suspend, reenable */
  	retval = pci_reenable_device(pci_dev);
  	/*
  	 * if the device was busmaster before the suspend, make it busmaster
  	 * again
  	 */
  	if (pci_dev->is_busmaster)
  		pci_set_master(pci_dev);
  
  	return retval;
  }
  
  static int pci_legacy_suspend(struct device *dev, pm_message_t state)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = pci_dev->driver;
  
  	if (drv && drv->suspend) {
  		pci_power_t prev = pci_dev->current_state;
  		int error;
  
  		error = drv->suspend(pci_dev, state);
  		suspend_report_result(drv->suspend, error);
  		if (error)
  			return error;
  
  		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
  		    && pci_dev->current_state != PCI_UNKNOWN) {
  			WARN_ONCE(pci_dev->current_state != prev,
  				"PCI PM: Device state not saved by %pS\n",
  				drv->suspend);
  		}
  	}
  
  	pci_fixup_device(pci_fixup_suspend, pci_dev);
  
  	return 0;
  }
  
  static int pci_legacy_suspend_late(struct device *dev, pm_message_t state)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = pci_dev->driver;
  
  	if (drv && drv->suspend_late) {
  		pci_power_t prev = pci_dev->current_state;
  		int error;
  
  		error = drv->suspend_late(pci_dev, state);
  		suspend_report_result(drv->suspend_late, error);
  		if (error)
  			return error;
  
  		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
  		    && pci_dev->current_state != PCI_UNKNOWN) {
  			WARN_ONCE(pci_dev->current_state != prev,
  				"PCI PM: Device state not saved by %pS\n",
  				drv->suspend_late);
  			goto Fixup;
  		}
  	}
  
  	if (!pci_dev->state_saved)
  		pci_save_state(pci_dev);
  
  	pci_pm_set_unknown_state(pci_dev);
  
  Fixup:
  	pci_fixup_device(pci_fixup_suspend_late, pci_dev);
  
  	return 0;
  }
  
  static int pci_legacy_resume_early(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = pci_dev->driver;
  
  	return drv && drv->resume_early ?
  			drv->resume_early(pci_dev) : 0;
  }
  
  static int pci_legacy_resume(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *drv = pci_dev->driver;
  
  	pci_fixup_device(pci_fixup_resume, pci_dev);
  
  	return drv && drv->resume ?
  			drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev);
  }
  
  /* Auxiliary functions used by the new power management framework */
  
  static void pci_pm_default_resume(struct pci_dev *pci_dev)
  {
  	pci_fixup_device(pci_fixup_resume, pci_dev);
  	pci_enable_wake(pci_dev, PCI_D0, false);
  }
  
  static void pci_pm_default_suspend(struct pci_dev *pci_dev)
  {
  	/* Disable non-bridge devices without PM support */
  	if (!pci_has_subordinate(pci_dev))
  		pci_disable_enabled_device(pci_dev);
  }
  
  static bool pci_has_legacy_pm_support(struct pci_dev *pci_dev)
  {
  	struct pci_driver *drv = pci_dev->driver;
  	bool ret = drv && (drv->suspend || drv->suspend_late || drv->resume
  		|| drv->resume_early);
  
  	/*
  	 * Legacy PM support is used by default, so warn if the new framework is
  	 * supported as well.  Drivers are supposed to support either the
  	 * former, or the latter, but not both at the same time.
  	 */
  	WARN(ret && drv->driver.pm, "driver %s device %04x:%04x\n",
  		drv->name, pci_dev->vendor, pci_dev->device);
  
  	return ret;
  }
  
  /* New power management framework */
  
  static int pci_pm_prepare(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  
  	if (drv && drv->pm && drv->pm->prepare) {
  		int error = drv->pm->prepare(dev);
  		if (error < 0)
  			return error;
  
  		if (!error && dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_PREPARE))
  			return 0;
  	}
  	if (pci_dev_need_resume(pci_dev))
  		return 0;
  
  	/*
  	 * The PME setting needs to be adjusted here in case the direct-complete
  	 * optimization is used with respect to this device.
  	 */
  	pci_dev_adjust_pme(pci_dev);
  	return 1;
  }
  
  static void pci_pm_complete(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  
  	pci_dev_complete_resume(pci_dev);
  	pm_generic_complete(dev);
  
  	/* Resume device if platform firmware has put it in reset-power-on */
  	if (pm_runtime_suspended(dev) && pm_resume_via_firmware()) {
  		pci_power_t pre_sleep_state = pci_dev->current_state;
  
  		pci_refresh_power_state(pci_dev);
  		/*
  		 * On platforms with ACPI this check may also trigger for
  		 * devices sharing power resources if one of those power
  		 * resources has been activated as a result of a change of the
  		 * power state of another device sharing it.  However, in that
  		 * case it is also better to resume the device, in general.
  		 */
  		if (pci_dev->current_state < pre_sleep_state)
  			pm_request_resume(dev);
  	}
  }
  
  #else /* !CONFIG_PM_SLEEP */
  
  #define pci_pm_prepare	NULL
  #define pci_pm_complete	NULL
  
  #endif /* !CONFIG_PM_SLEEP */
  
  #ifdef CONFIG_SUSPEND
  static void pcie_pme_root_status_cleanup(struct pci_dev *pci_dev)
  {
  	/*
  	 * Some BIOSes forget to clear Root PME Status bits after system
  	 * wakeup, which breaks ACPI-based runtime wakeup on PCI Express.
  	 * Clear those bits now just in case (shouldn't hurt).
  	 */
  	if (pci_is_pcie(pci_dev) &&
  	    (pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT ||
  	     pci_pcie_type(pci_dev) == PCI_EXP_TYPE_RC_EC))
  		pcie_clear_root_pme_status(pci_dev);
  }
  
  static int pci_pm_suspend(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  
  	pci_dev->skip_bus_pm = false;
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_suspend(dev, PMSG_SUSPEND);
  
  	if (!pm) {
  		pci_pm_default_suspend(pci_dev);
  		return 0;
  	}
  
  	/*
  	 * PCI devices suspended at run time may need to be resumed at this
  	 * point, because in general it may be necessary to reconfigure them for
  	 * system suspend.  Namely, if the device is expected to wake up the
  	 * system from the sleep state, it may have to be reconfigured for this
  	 * purpose, or if the device is not expected to wake up the system from
  	 * the sleep state, it should be prevented from signaling wakeup events
  	 * going forward.
  	 *
  	 * Also if the driver of the device does not indicate that its system
  	 * suspend callbacks can cope with runtime-suspended devices, it is
  	 * better to resume the device from runtime suspend here.
  	 */
  	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
  	    pci_dev_need_resume(pci_dev)) {
  		pm_runtime_resume(dev);
  		pci_dev->state_saved = false;
  	} else {
  		pci_dev_adjust_pme(pci_dev);
  	}
  
  	if (pm->suspend) {
  		pci_power_t prev = pci_dev->current_state;
  		int error;
  
  		error = pm->suspend(dev);
  		suspend_report_result(pm->suspend, error);
  		if (error)
  			return error;
  
  		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
  		    && pci_dev->current_state != PCI_UNKNOWN) {
  			WARN_ONCE(pci_dev->current_state != prev,
  				"PCI PM: State of device not saved by %pS\n",
  				pm->suspend);
  		}
  	}
  
  	return 0;
  }
  
  static int pci_pm_suspend_late(struct device *dev)
  {
  	if (dev_pm_smart_suspend_and_suspended(dev))
  		return 0;
  
  	pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev));
  
  	return pm_generic_suspend_late(dev);
  }
  
  static int pci_pm_suspend_noirq(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  
  	if (dev_pm_smart_suspend_and_suspended(dev)) {
  		dev->power.may_skip_resume = true;
  		return 0;
  	}
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_suspend_late(dev, PMSG_SUSPEND);
  
  	if (!pm) {
  		pci_save_state(pci_dev);
  		goto Fixup;
  	}
  
  	if (pm->suspend_noirq) {
  		pci_power_t prev = pci_dev->current_state;
  		int error;
  
  		error = pm->suspend_noirq(dev);
  		suspend_report_result(pm->suspend_noirq, error);
  		if (error)
  			return error;
  
  		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
  		    && pci_dev->current_state != PCI_UNKNOWN) {
  			WARN_ONCE(pci_dev->current_state != prev,
  				"PCI PM: State of device not saved by %pS\n",
  				pm->suspend_noirq);
  			goto Fixup;
  		}
  	}
  
  	if (pci_dev->skip_bus_pm) {
  		/*
  		 * Either the device is a bridge with a child in D0 below it, or
  		 * the function is running for the second time in a row without
  		 * going through full resume, which is possible only during
  		 * suspend-to-idle in a spurious wakeup case.  The device should
  		 * be in D0 at this point, but if it is a bridge, it may be
  		 * necessary to save its state.
  		 */
  		if (!pci_dev->state_saved)
  			pci_save_state(pci_dev);
  	} else if (!pci_dev->state_saved) {
  		pci_save_state(pci_dev);
  		if (pci_power_manageable(pci_dev))
  			pci_prepare_to_sleep(pci_dev);
  	}
  
  	dev_dbg(dev, "PCI PM: Suspend power state: %s\n",
  		pci_power_name(pci_dev->current_state));
  
  	if (pci_dev->current_state == PCI_D0) {
  		pci_dev->skip_bus_pm = true;
  		/*
  		 * Per PCI PM r1.2, table 6-1, a bridge must be in D0 if any
  		 * downstream device is in D0, so avoid changing the power state
  		 * of the parent bridge by setting the skip_bus_pm flag for it.
  		 */
  		if (pci_dev->bus->self)
  			pci_dev->bus->self->skip_bus_pm = true;
  	}
  
  	if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) {
  		dev_dbg(dev, "PCI PM: Skipped\n");
  		goto Fixup;
  	}
  
  	pci_pm_set_unknown_state(pci_dev);
  
  	/*
  	 * Some BIOSes from ASUS have a bug: If a USB EHCI host controller's
  	 * PCI COMMAND register isn't 0, the BIOS assumes that the controller
  	 * hasn't been quiesced and tries to turn it off.  If the controller
  	 * is already in D3, this can hang or cause memory corruption.
  	 *
  	 * Since the value of the COMMAND register doesn't matter once the
  	 * device has been suspended, we can safely set it to 0 here.
  	 */
  	if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
  		pci_write_config_word(pci_dev, PCI_COMMAND, 0);
  
  Fixup:
  	pci_fixup_device(pci_fixup_suspend_late, pci_dev);
  
  	/*
  	 * If the target system sleep state is suspend-to-idle, it is sufficient
  	 * to check whether or not the device's wakeup settings are good for
  	 * runtime PM.  Otherwise, the pm_resume_via_firmware() check will cause
  	 * pci_pm_complete() to take care of fixing up the device's state
  	 * anyway, if need be.
  	 */
  	dev->power.may_skip_resume = device_may_wakeup(dev) ||
  					!device_can_wakeup(dev);
  
  	return 0;
  }
  
  static int pci_pm_resume_noirq(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct device_driver *drv = dev->driver;
  	int error = 0;
  
  	if (dev_pm_may_skip_resume(dev))
  		return 0;
  
  	/*
  	 * Devices with DPM_FLAG_SMART_SUSPEND may be left in runtime suspend
  	 * during system suspend, so update their runtime PM status to "active"
  	 * as they are going to be put into D0 shortly.
  	 */
  	if (dev_pm_smart_suspend_and_suspended(dev))
  		pm_runtime_set_active(dev);
  
  	/*
  	 * In the suspend-to-idle case, devices left in D0 during suspend will
  	 * stay in D0, so it is not necessary to restore or update their
  	 * configuration here and attempting to put them into D0 again is
  	 * pointless, so avoid doing that.
  	 */
  	if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform()))
  		pci_pm_default_resume_early(pci_dev);
  
  	pci_fixup_device(pci_fixup_resume_early, pci_dev);
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_resume_early(dev);
  
  	pcie_pme_root_status_cleanup(pci_dev);
  
  	if (drv && drv->pm && drv->pm->resume_noirq)
  		error = drv->pm->resume_noirq(dev);
  
  	return error;
  }
  
  static int pci_pm_resume(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  	int error = 0;
  
  	/*
  	 * This is necessary for the suspend error path in which resume is
  	 * called without restoring the standard config registers of the device.
  	 */
  	if (pci_dev->state_saved)
  		pci_restore_standard_config(pci_dev);
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_resume(dev);
  
  	pci_pm_default_resume(pci_dev);
  
  	if (pm) {
  		if (pm->resume)
  			error = pm->resume(dev);
  	} else {
  		pci_pm_reenable_device(pci_dev);
  	}
  
  	return error;
  }
  
  #else /* !CONFIG_SUSPEND */
  
  #define pci_pm_suspend		NULL
  #define pci_pm_suspend_late	NULL
  #define pci_pm_suspend_noirq	NULL
  #define pci_pm_resume		NULL
  #define pci_pm_resume_noirq	NULL
  
  #endif /* !CONFIG_SUSPEND */
  
  #ifdef CONFIG_HIBERNATE_CALLBACKS
  
  
  /*
   * pcibios_pm_ops - provide arch-specific hooks when a PCI device is doing
   * a hibernate transition
   */
  struct dev_pm_ops __weak pcibios_pm_ops;
  
  static int pci_pm_freeze(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_suspend(dev, PMSG_FREEZE);
  
  	if (!pm) {
  		pci_pm_default_suspend(pci_dev);
  		return 0;
  	}
  
  	/*
  	 * Resume all runtime-suspended devices before creating a snapshot
  	 * image of system memory, because the restore kernel generally cannot
  	 * be expected to always handle them consistently and they need to be
  	 * put into the runtime-active metastate during system resume anyway,
  	 * so it is better to ensure that the state saved in the image will be
  	 * always consistent with that.
  	 */
  	pm_runtime_resume(dev);
  	pci_dev->state_saved = false;
  
  	if (pm->freeze) {
  		int error;
  
  		error = pm->freeze(dev);
  		suspend_report_result(pm->freeze, error);
  		if (error)
  			return error;
  	}
  
  	return 0;
  }
  
  static int pci_pm_freeze_noirq(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct device_driver *drv = dev->driver;
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_suspend_late(dev, PMSG_FREEZE);
  
  	if (drv && drv->pm && drv->pm->freeze_noirq) {
  		int error;
  
  		error = drv->pm->freeze_noirq(dev);
  		suspend_report_result(drv->pm->freeze_noirq, error);
  		if (error)
  			return error;
  	}
  
  	if (!pci_dev->state_saved)
  		pci_save_state(pci_dev);
  
  	pci_pm_set_unknown_state(pci_dev);
  
  	if (pcibios_pm_ops.freeze_noirq)
  		return pcibios_pm_ops.freeze_noirq(dev);
  
  	return 0;
  }
  
  static int pci_pm_thaw_noirq(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct device_driver *drv = dev->driver;
  	int error = 0;
  
  	if (pcibios_pm_ops.thaw_noirq) {
  		error = pcibios_pm_ops.thaw_noirq(dev);
  		if (error)
  			return error;
  	}
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_resume_early(dev);
  
  	/*
  	 * pci_restore_state() requires the device to be in D0 (because of MSI
  	 * restoration among other things), so force it into D0 in case the
  	 * driver's "freeze" callbacks put it into a low-power state directly.
  	 */
  	pci_set_power_state(pci_dev, PCI_D0);
  	pci_restore_state(pci_dev);
  
  	if (drv && drv->pm && drv->pm->thaw_noirq)
  		error = drv->pm->thaw_noirq(dev);
  
  	return error;
  }
  
  static int pci_pm_thaw(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  	int error = 0;
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_resume(dev);
  
  	if (pm) {
  		if (pm->thaw)
  			error = pm->thaw(dev);
  	} else {
  		pci_pm_reenable_device(pci_dev);
  	}
  
  	pci_dev->state_saved = false;
  
  	return error;
  }
  
  static int pci_pm_poweroff(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_suspend(dev, PMSG_HIBERNATE);
  
  	if (!pm) {
  		pci_pm_default_suspend(pci_dev);
  		return 0;
  	}
  
  	/* The reason to do that is the same as in pci_pm_suspend(). */
  	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
  	    pci_dev_need_resume(pci_dev)) {
  		pm_runtime_resume(dev);
  		pci_dev->state_saved = false;
  	} else {
  		pci_dev_adjust_pme(pci_dev);
  	}
  
  	if (pm->poweroff) {
  		int error;
  
  		error = pm->poweroff(dev);
  		suspend_report_result(pm->poweroff, error);
  		if (error)
  			return error;
  	}
  
  	return 0;
  }
  
  static int pci_pm_poweroff_late(struct device *dev)
  {
  	if (dev_pm_smart_suspend_and_suspended(dev))
  		return 0;
  
  	pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev));
  
  	return pm_generic_poweroff_late(dev);
  }
  
  static int pci_pm_poweroff_noirq(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct device_driver *drv = dev->driver;
  
  	if (dev_pm_smart_suspend_and_suspended(dev))
  		return 0;
  
  	if (pci_has_legacy_pm_support(to_pci_dev(dev)))
  		return pci_legacy_suspend_late(dev, PMSG_HIBERNATE);
  
  	if (!drv || !drv->pm) {
  		pci_fixup_device(pci_fixup_suspend_late, pci_dev);
  		return 0;
  	}
  
  	if (drv->pm->poweroff_noirq) {
  		int error;
  
  		error = drv->pm->poweroff_noirq(dev);
  		suspend_report_result(drv->pm->poweroff_noirq, error);
  		if (error)
  			return error;
  	}
  
  	if (!pci_dev->state_saved && !pci_has_subordinate(pci_dev))
  		pci_prepare_to_sleep(pci_dev);
  
  	/*
  	 * The reason for doing this here is the same as for the analogous code
  	 * in pci_pm_suspend_noirq().
  	 */
  	if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
  		pci_write_config_word(pci_dev, PCI_COMMAND, 0);
  
  	pci_fixup_device(pci_fixup_suspend_late, pci_dev);
  
  	if (pcibios_pm_ops.poweroff_noirq)
  		return pcibios_pm_ops.poweroff_noirq(dev);
  
  	return 0;
  }
  
  static int pci_pm_restore_noirq(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct device_driver *drv = dev->driver;
  	int error = 0;
  
  	if (pcibios_pm_ops.restore_noirq) {
  		error = pcibios_pm_ops.restore_noirq(dev);
  		if (error)
  			return error;
  	}
  
  	pci_pm_default_resume_early(pci_dev);
  	pci_fixup_device(pci_fixup_resume_early, pci_dev);
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_resume_early(dev);
  
  	if (drv && drv->pm && drv->pm->restore_noirq)
  		error = drv->pm->restore_noirq(dev);
  
  	return error;
  }
  
  static int pci_pm_restore(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  	int error = 0;
  
  	/*
  	 * This is necessary for the hibernation error path in which restore is
  	 * called without restoring the standard config registers of the device.
  	 */
  	if (pci_dev->state_saved)
  		pci_restore_standard_config(pci_dev);
  
  	if (pci_has_legacy_pm_support(pci_dev))
  		return pci_legacy_resume(dev);
  
  	pci_pm_default_resume(pci_dev);
  
  	if (pm) {
  		if (pm->restore)
  			error = pm->restore(dev);
  	} else {
  		pci_pm_reenable_device(pci_dev);
  	}
  
  	return error;
  }
  
  #else /* !CONFIG_HIBERNATE_CALLBACKS */
  
  #define pci_pm_freeze		NULL
  #define pci_pm_freeze_noirq	NULL
  #define pci_pm_thaw		NULL
  #define pci_pm_thaw_noirq	NULL
  #define pci_pm_poweroff		NULL
  #define pci_pm_poweroff_late	NULL
  #define pci_pm_poweroff_noirq	NULL
  #define pci_pm_restore		NULL
  #define pci_pm_restore_noirq	NULL
  
  #endif /* !CONFIG_HIBERNATE_CALLBACKS */
  
  #ifdef CONFIG_PM
  
  static int pci_pm_runtime_suspend(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  	pci_power_t prev = pci_dev->current_state;
  	int error;
  
  	/*
  	 * If pci_dev->driver is not set (unbound), we leave the device in D0,
  	 * but it may go to D3cold when the bridge above it runtime suspends.
  	 * Save its config space in case that happens.
  	 */
  	if (!pci_dev->driver) {
  		pci_save_state(pci_dev);
  		return 0;
  	}
  
  	pci_dev->state_saved = false;
  	if (pm && pm->runtime_suspend) {
  		error = pm->runtime_suspend(dev);
  		/*
  		 * -EBUSY and -EAGAIN is used to request the runtime PM core
  		 * to schedule a new suspend, so log the event only with debug
  		 * log level.
  		 */
  		if (error == -EBUSY || error == -EAGAIN) {
  			dev_dbg(dev, "can't suspend now (%ps returned %d)\n",
  				pm->runtime_suspend, error);
  			return error;
  		} else if (error) {
  			dev_err(dev, "can't suspend (%ps returned %d)\n",
  				pm->runtime_suspend, error);
  			return error;
  		}
  	}
  
  	pci_fixup_device(pci_fixup_suspend, pci_dev);
  
  	if (pm && pm->runtime_suspend
  	    && !pci_dev->state_saved && pci_dev->current_state != PCI_D0
  	    && pci_dev->current_state != PCI_UNKNOWN) {
  		WARN_ONCE(pci_dev->current_state != prev,
  			"PCI PM: State of device not saved by %pS\n",
  			pm->runtime_suspend);
  		return 0;
  	}
  
  	if (!pci_dev->state_saved) {
  		pci_save_state(pci_dev);
  		pci_finish_runtime_suspend(pci_dev);
  	}
  
  	return 0;
  }
  
  static int pci_pm_runtime_resume(struct device *dev)
  {
  	int rc = 0;
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  
  	/*
  	 * Restoring config space is necessary even if the device is not bound
  	 * to a driver because although we left it in D0, it may have gone to
  	 * D3cold when the bridge above it runtime suspended.
  	 */
  	pci_restore_standard_config(pci_dev);
  
  	if (!pci_dev->driver)
  		return 0;
  
  	pci_fixup_device(pci_fixup_resume_early, pci_dev);
  	pci_enable_wake(pci_dev, PCI_D0, false);
  	pci_fixup_device(pci_fixup_resume, pci_dev);
  
  	if (pm && pm->runtime_resume)
  		rc = pm->runtime_resume(dev);
  
  	pci_dev->runtime_d3cold = false;
  
  	return rc;
  }
  
  static int pci_pm_runtime_idle(struct device *dev)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  	int ret = 0;
  
  	/*
  	 * If pci_dev->driver is not set (unbound), the device should
  	 * always remain in D0 regardless of the runtime PM status
  	 */
  	if (!pci_dev->driver)
  		return 0;
  
  	if (!pm)
  		return -ENOSYS;
  
  	if (pm->runtime_idle)
  		ret = pm->runtime_idle(dev);
  
  	return ret;
  }
  
  static const struct dev_pm_ops pci_dev_pm_ops = {
  	.prepare = pci_pm_prepare,
  	.complete = pci_pm_complete,
  	.suspend = pci_pm_suspend,
  	.suspend_late = pci_pm_suspend_late,
  	.resume = pci_pm_resume,
  	.freeze = pci_pm_freeze,
  	.thaw = pci_pm_thaw,
  	.poweroff = pci_pm_poweroff,
  	.poweroff_late = pci_pm_poweroff_late,
  	.restore = pci_pm_restore,
  	.suspend_noirq = pci_pm_suspend_noirq,
  	.resume_noirq = pci_pm_resume_noirq,
  	.freeze_noirq = pci_pm_freeze_noirq,
  	.thaw_noirq = pci_pm_thaw_noirq,
  	.poweroff_noirq = pci_pm_poweroff_noirq,
  	.restore_noirq = pci_pm_restore_noirq,
  	.runtime_suspend = pci_pm_runtime_suspend,
  	.runtime_resume = pci_pm_runtime_resume,
  	.runtime_idle = pci_pm_runtime_idle,
  };
  
  #define PCI_PM_OPS_PTR	(&pci_dev_pm_ops)
  
  #else /* !CONFIG_PM */
  
  #define pci_pm_runtime_suspend	NULL
  #define pci_pm_runtime_resume	NULL
  #define pci_pm_runtime_idle	NULL
  
  #define PCI_PM_OPS_PTR	NULL
  
  #endif /* !CONFIG_PM */
  
  /**
   * __pci_register_driver - register a new pci driver
   * @drv: the driver structure to register
   * @owner: owner module of drv
   * @mod_name: module name string
   *
   * Adds the driver structure to the list of registered drivers.
   * Returns a negative value on error, otherwise 0.
   * If no error occurred, the driver remains registered even if
   * no device was claimed during registration.
   */
  int __pci_register_driver(struct pci_driver *drv, struct module *owner,
  			  const char *mod_name)
  {
  	/* initialize common driver fields */
  	drv->driver.name = drv->name;
  	drv->driver.bus = &pci_bus_type;
  	drv->driver.owner = owner;
  	drv->driver.mod_name = mod_name;
  	drv->driver.groups = drv->groups;
  
  	spin_lock_init(&drv->dynids.lock);
  	INIT_LIST_HEAD(&drv->dynids.list);
  
  	/* register with core */
  	return driver_register(&drv->driver);
  }
  EXPORT_SYMBOL(__pci_register_driver);
  
  /**
   * pci_unregister_driver - unregister a pci driver
   * @drv: the driver structure to unregister
   *
   * Deletes the driver structure from the list of registered PCI drivers,
   * gives it a chance to clean up by calling its remove() function for
   * each device it was responsible for, and marks those devices as
   * driverless.
   */
  
  void pci_unregister_driver(struct pci_driver *drv)
  {
  	driver_unregister(&drv->driver);
  	pci_free_dynids(drv);
  }
  EXPORT_SYMBOL(pci_unregister_driver);
  
  static struct pci_driver pci_compat_driver = {
  	.name = "compat"
  };
  
  /**
   * pci_dev_driver - get the pci_driver of a device
   * @dev: the device to query
   *
   * Returns the appropriate pci_driver structure or %NULL if there is no
   * registered driver for the device.
   */
  struct pci_driver *pci_dev_driver(const struct pci_dev *dev)
  {
  	if (dev->driver)
  		return dev->driver;
  	else {
  		int i;
  		for (i = 0; i <= PCI_ROM_RESOURCE; i++)
  			if (dev->resource[i].flags & IORESOURCE_BUSY)
  				return &pci_compat_driver;
  	}
  	return NULL;
  }
  EXPORT_SYMBOL(pci_dev_driver);
  
  /**
   * pci_bus_match - Tell if a PCI device structure has a matching PCI device id structure
   * @dev: the PCI device structure to match against
   * @drv: the device driver to search for matching PCI device id structures
   *
   * Used by a driver to check whether a PCI device present in the
   * system is in its list of supported devices. Returns the matching
   * pci_device_id structure or %NULL if there is no match.
   */
  static int pci_bus_match(struct device *dev, struct device_driver *drv)
  {
  	struct pci_dev *pci_dev = to_pci_dev(dev);
  	struct pci_driver *pci_drv;
  	const struct pci_device_id *found_id;
  
  	if (!pci_dev->match_driver)
  		return 0;
  
  	pci_drv = to_pci_driver(drv);
  	found_id = pci_match_device(pci_drv, pci_dev);
  	if (found_id)
  		return 1;
  
  	return 0;
  }
  
  /**
   * pci_dev_get - increments the reference count of the pci device structure
   * @dev: the device being referenced
   *
   * Each live reference to a device should be refcounted.
   *
   * Drivers for PCI devices should normally record such references in
   * their probe() methods, when they bind to a device, and release
   * them by calling pci_dev_put(), in their disconnect() methods.
   *
   * A pointer to the device with the incremented reference counter is returned.
   */
  struct pci_dev *pci_dev_get(struct pci_dev *dev)
  {
  	if (dev)
  		get_device(&dev->dev);
  	return dev;
  }
  EXPORT_SYMBOL(pci_dev_get);
  
  /**
   * pci_dev_put - release a use of the pci device structure
   * @dev: device that's been disconnected
   *
   * Must be called when a user of a device is finished with it.  When the last
   * user of the device calls this function, the memory of the device is freed.
   */
  void pci_dev_put(struct pci_dev *dev)
  {
  	if (dev)
  		put_device(&dev->dev);
  }
  EXPORT_SYMBOL(pci_dev_put);
  
  static int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct pci_dev *pdev;
  
  	if (!dev)
  		return -ENODEV;
  
  	pdev = to_pci_dev(dev);
  
  	if (add_uevent_var(env, "PCI_CLASS=%04X", pdev->class))
  		return -ENOMEM;
  
  	if (add_uevent_var(env, "PCI_ID=%04X:%04X", pdev->vendor, pdev->device))
  		return -ENOMEM;
  
  	if (add_uevent_var(env, "PCI_SUBSYS_ID=%04X:%04X", pdev->subsystem_vendor,
  			   pdev->subsystem_device))
  		return -ENOMEM;
  
  	if (add_uevent_var(env, "PCI_SLOT_NAME=%s", pci_name(pdev)))
  		return -ENOMEM;
  
  	if (add_uevent_var(env, "MODALIAS=pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02X",
  			   pdev->vendor, pdev->device,
  			   pdev->subsystem_vendor, pdev->subsystem_device,
  			   (u8)(pdev->class >> 16), (u8)(pdev->class >> 8),
  			   (u8)(pdev->class)))
  		return -ENOMEM;
  
  	return 0;
  }
  
  #if defined(CONFIG_PCIEPORTBUS) || defined(CONFIG_EEH)
  /**
   * pci_uevent_ers - emit a uevent during recovery path of PCI device
   * @pdev: PCI device undergoing error recovery
   * @err_type: type of error event
   */
  void pci_uevent_ers(struct pci_dev *pdev, enum pci_ers_result err_type)
  {
  	int idx = 0;
  	char *envp[3];
  
  	switch (err_type) {
  	case PCI_ERS_RESULT_NONE:
  	case PCI_ERS_RESULT_CAN_RECOVER:
  		envp[idx++] = "ERROR_EVENT=BEGIN_RECOVERY";
  		envp[idx++] = "DEVICE_ONLINE=0";
  		break;
  	case PCI_ERS_RESULT_RECOVERED:
  		envp[idx++] = "ERROR_EVENT=SUCCESSFUL_RECOVERY";
  		envp[idx++] = "DEVICE_ONLINE=1";
  		break;
  	case PCI_ERS_RESULT_DISCONNECT:
  		envp[idx++] = "ERROR_EVENT=FAILED_RECOVERY";
  		envp[idx++] = "DEVICE_ONLINE=0";
  		break;
  	default:
  		break;
  	}
  
  	if (idx > 0) {
  		envp[idx++] = NULL;
  		kobject_uevent_env(&pdev->dev.kobj, KOBJ_CHANGE, envp);
  	}
  }
  #endif
  
  static int pci_bus_num_vf(struct device *dev)
  {
  	return pci_num_vf(to_pci_dev(dev));
  }
  
  /**
   * pci_dma_configure - Setup DMA configuration
   * @dev: ptr to dev structure
   *
   * Function to update PCI devices's DMA configuration using the same
   * info from the OF node or ACPI node of host bridge's parent (if any).
   */
  static int pci_dma_configure(struct device *dev)
  {
  	struct device *bridge;
  	int ret = 0;
  
  	bridge = pci_get_host_bridge_device(to_pci_dev(dev));
  
  	if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
  	    bridge->parent->of_node) {
  		ret = of_dma_configure(dev, bridge->parent->of_node, true);
  	} else if (has_acpi_companion(bridge)) {
  		struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
  
  		ret = acpi_dma_configure(dev, acpi_get_dma_attr(adev));
  	}
  
  	pci_put_host_bridge_device(bridge);
  	return ret;
  }
  
  struct bus_type pci_bus_type = {
  	.name		= "pci",
  	.match		= pci_bus_match,
  	.uevent		= pci_uevent,
  	.probe		= pci_device_probe,
  	.remove		= pci_device_remove,
  	.shutdown	= pci_device_shutdown,
  	.dev_groups	= pci_dev_groups,
  	.bus_groups	= pci_bus_groups,
  	.drv_groups	= pci_drv_groups,
  	.pm		= PCI_PM_OPS_PTR,
  	.num_vf		= pci_bus_num_vf,
  	.dma_configure	= pci_dma_configure,
  };
  EXPORT_SYMBOL(pci_bus_type);
  
  #ifdef CONFIG_PCIEPORTBUS
  static int pcie_port_bus_match(struct device *dev, struct device_driver *drv)
  {
  	struct pcie_device *pciedev;
  	struct pcie_port_service_driver *driver;
  
  	if (drv->bus != &pcie_port_bus_type || dev->bus != &pcie_port_bus_type)
  		return 0;
  
  	pciedev = to_pcie_device(dev);
  	driver = to_service_driver(drv);
  
  	if (driver->service != pciedev->service)
  		return 0;
  
  	if (driver->port_type != PCIE_ANY_PORT &&
  	    driver->port_type != pci_pcie_type(pciedev->port))
  		return 0;
  
  	return 1;
  }
  
  struct bus_type pcie_port_bus_type = {
  	.name		= "pci_express",
  	.match		= pcie_port_bus_match,
  };
  EXPORT_SYMBOL_GPL(pcie_port_bus_type);
  #endif
  
  static int __init pci_driver_init(void)
  {
  	int ret;
  
  	ret = bus_register(&pci_bus_type);
  	if (ret)
  		return ret;
  
  #ifdef CONFIG_PCIEPORTBUS
  	ret = bus_register(&pcie_port_bus_type);
  	if (ret)
  		return ret;
  #endif
  	dma_debug_add_bus(&pci_bus_type);
  	return 0;
  }
  postcore_initcall(pci_driver_init);
  