Merge tag 'drm-misc-fixes-2020-03-18-1' of git://anongit.freedesktop.org/drm/drm...

[mirror_ubuntu-jammy-kernel.git] / drivers / pci / pci-driver.c

// 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.
         */
        pci_warn(pci_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;
}

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);
}

#endif

#ifdef CONFIG_PM_SLEEP

static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
{
        pci_power_up(pci_dev);
        pci_update_current_state(pci_dev, PCI_D0);
        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) {
                        pci_WARN_ONCE(pci_dev, 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);

        if (!pci_dev->state_saved)
                pci_save_state(pci_dev);

        pci_pm_set_unknown_state(pci_dev);

        pci_fixup_device(pci_fixup_suspend_late, pci_dev);

        return 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_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->resume);

        /*
         * 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.
         */
        pci_WARN(pci_dev, ret && drv->driver.pm, "device %04x:%04x\n",
                 pci_dev->vendor, pci_dev->device);

        return ret;
}

/* New power management framework */

static int pci_pm_prepare(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 (pm && pm->prepare) {
                int error = 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) {
                        pci_WARN_ONCE(pci_dev, 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) {
                        pci_WARN_ONCE(pci_dev, 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);
        }

        pci_dbg(pci_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()) {
                pci_dbg(pci_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);
        const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
        pci_power_t prev_state = pci_dev->current_state;
        bool skip_bus_pm = pci_dev->skip_bus_pm;

        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 (!(skip_bus_pm && pm_suspend_no_platform()))
                pci_pm_default_resume_early(pci_dev);

        pci_fixup_device(pci_fixup_resume_early, pci_dev);
        pcie_pme_root_status_cleanup(pci_dev);

        if (!skip_bus_pm && prev_state == PCI_D3cold)
                pci_bridge_wait_for_secondary_bus(pci_dev);

        if (pci_has_legacy_pm_support(pci_dev))
                return 0;

        if (pm && pm->resume_noirq)
                return pm->resume_noirq(dev);

        return 0;
}

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;

        /*
         * 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)
                        return pm->resume(dev);
        } else {
                pci_pm_reenable_device(pci_dev);
        }

        return 0;
}

#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);
        const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

        if (pci_has_legacy_pm_support(pci_dev))
                return pci_legacy_suspend_late(dev, PMSG_FREEZE);

        if (pm && pm->freeze_noirq) {
                int error;

                error = pm->freeze_noirq(dev);
                suspend_report_result(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);
        const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
        int error;

        if (pcibios_pm_ops.thaw_noirq) {
                error = pcibios_pm_ops.thaw_noirq(dev);
                if (error)
                        return error;
        }

        /*
         * The pm->thaw_noirq() callback assumes the device has been
         * returned to D0 and its config state has been restored.
         *
         * In addition, pci_restore_state() restores MSI-X state in MMIO
         * space, which requires the device to be in D0, so return it to D0
         * in case the driver's "freeze" callbacks put it into a low-power
         * state.
         */
        pci_set_power_state(pci_dev, PCI_D0);
        pci_restore_state(pci_dev);

        if (pci_has_legacy_pm_support(pci_dev))
                return 0;

        if (pm && pm->thaw_noirq)
                return pm->thaw_noirq(dev);

        return 0;
}

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);
        const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

        if (dev_pm_smart_suspend_and_suspended(dev))
                return 0;

        if (pci_has_legacy_pm_support(pci_dev))
                return pci_legacy_suspend_late(dev, PMSG_HIBERNATE);

        if (!pm) {
                pci_fixup_device(pci_fixup_suspend_late, pci_dev);
                return 0;
        }

        if (pm->poweroff_noirq) {
                int error;

                error = pm->poweroff_noirq(dev);
                suspend_report_result(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);
        const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
        int error;

        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 0;

        if (pm && pm->restore_noirq)
                return pm->restore_noirq(dev);

        return 0;
}

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;

        /*
         * 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)
                        return pm->restore(dev);
        } else {
                pci_pm_reenable_device(pci_dev);
        }

        return 0;
}

#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) {
                        pci_dbg(pci_dev, "can't suspend now (%ps returned %d)\n",
                                pm->runtime_suspend, error);
                        return error;
                } else if (error) {
                        pci_err(pci_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) {
                pci_WARN_ONCE(pci_dev, 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)
{
        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_state = pci_dev->current_state;
        int error = 0;

        /*
         * 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_pm_default_resume(pci_dev);

        if (prev_state == PCI_D3cold)
                pci_bridge_wait_for_secondary_bus(pci_dev);

        if (pm && pm->runtime_resume)
                error = pm->runtime_resume(dev);

        pci_dev->runtime_d3cold = false;

        return error;
}

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;

        /*
         * 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)
                return pm->runtime_idle(dev);

        return 0;
}

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);