// SPDX-License-Identifier: GPL-2.0
/*
 * Purpose:     PCI Express Port Bus Driver
 *
 * Copyright (C) 2004 Intel
 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
 */

#include <linux/bitfield.h>
#include <linux/dmi.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/aer.h>

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

/*
 * The PCIe Capability Interrupt Message Number (PCIe r3.1, sec 7.8.2) must
 * be one of the first 32 MSI-X entries.  Per PCI r3.0, sec 6.8.3.1, MSI
 * supports a maximum of 32 vectors per function.
 */
#define PCIE_PORT_MAX_MSI_ENTRIES       32

#define get_descriptor_id(type, service) (((type - 4) << 8) | service)

struct portdrv_service_data {
        struct pcie_port_service_driver *drv;
        struct device *dev;
        u32 service;
};

/**
 * release_pcie_device - free PCI Express port service device structure
 * @dev: Port service device to release
 *
 * Invoked automatically when device is being removed in response to
 * device_unregister(dev).  Release all resources being claimed.
 */
static void release_pcie_device(struct device *dev)
{
        kfree(to_pcie_device(dev));
}

/*
 * Fill in *pme, *aer, *dpc with the relevant Interrupt Message Numbers if
 * services are enabled in "mask".  Return the number of MSI/MSI-X vectors
 * required to accommodate the largest Message Number.
 */
static int pcie_message_numbers(struct pci_dev *dev, int mask,
                                u32 *pme, u32 *aer, u32 *dpc)
{
        u32 nvec = 0, pos;
        u16 reg16;

        /*
         * The Interrupt Message Number indicates which vector is used, i.e.,
         * the MSI-X table entry or the MSI offset between the base Message
         * Data and the generated interrupt message.  See PCIe r3.1, sec
         * 7.8.2, 7.10.10, 7.31.2.
         */

        if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
                    PCIE_PORT_SERVICE_BWCTRL)) {
                pcie_capability_read_word(dev, PCI_EXP_FLAGS, &reg16);
                *pme = FIELD_GET(PCI_EXP_FLAGS_IRQ, reg16);
                nvec = *pme + 1;
        }

#ifdef CONFIG_PCIEAER
        if (mask & PCIE_PORT_SERVICE_AER) {
                u32 reg32;

                pos = dev->aer_cap;
                if (pos) {
                        pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS,
                                              &reg32);
                        *aer = FIELD_GET(PCI_ERR_ROOT_AER_IRQ, reg32);
                        nvec = max(nvec, *aer + 1);
                }
        }
#endif

        if (mask & PCIE_PORT_SERVICE_DPC) {
                pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
                if (pos) {
                        pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP,
                                             &reg16);
                        *dpc = FIELD_GET(PCI_EXP_DPC_IRQ, reg16);
                        nvec = max(nvec, *dpc + 1);
                }
        }

        return nvec;
}

/**
 * pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
 * for given port
 * @dev: PCI Express port to handle
 * @irqs: Array of interrupt vectors to populate
 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 *
 * Return value: 0 on success, error code on failure
 */
static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
{
        int nr_entries, nvec, pcie_irq;
        u32 pme = 0, aer = 0, dpc = 0;

        /* Allocate the maximum possible number of MSI/MSI-X vectors */
        nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
                        PCI_IRQ_MSIX | PCI_IRQ_MSI);
        if (nr_entries < 0)
                return nr_entries;

        /* See how many and which Interrupt Message Numbers we actually use */
        nvec = pcie_message_numbers(dev, mask, &pme, &aer, &dpc);
        if (nvec > nr_entries) {
                pci_free_irq_vectors(dev);
                return -EIO;
        }

        /*
         * If we allocated more than we need, free them and reallocate fewer.
         *
         * Reallocating may change the specific vectors we get, so
         * pci_irq_vector() must be done *after* the reallocation.
         *
         * If we're using MSI, hardware is *allowed* to change the Interrupt
         * Message Numbers when we free and reallocate the vectors, but we
         * assume it won't because we allocate enough vectors for the
         * biggest Message Number we found.
         */
        if (nvec != nr_entries) {
                pci_free_irq_vectors(dev);

                nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
                                PCI_IRQ_MSIX | PCI_IRQ_MSI);
                if (nr_entries < 0)
                        return nr_entries;
        }

        /* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */
        if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
                    PCIE_PORT_SERVICE_BWCTRL)) {
                pcie_irq = pci_irq_vector(dev, pme);
                irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq;
                irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq;
                irqs[PCIE_PORT_SERVICE_BWCTRL_SHIFT] = pcie_irq;
        }

        if (mask & PCIE_PORT_SERVICE_AER)
                irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, aer);

        if (mask & PCIE_PORT_SERVICE_DPC)
                irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, dpc);

        return 0;
}

/**
 * pcie_init_service_irqs - initialize irqs for PCI Express port services
 * @dev: PCI Express port to handle
 * @irqs: Array of irqs to populate
 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 *
 * Return value: Interrupt mode associated with the port
 */
static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
{
        int ret, i;

        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
                irqs[i] = -1;

        /*
         * If we support PME but can't use MSI/MSI-X for it, we have to
         * fall back to INTx or other interrupts, e.g., a system shared
         * interrupt.
         */
        if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
                goto intx_irq;

        /* Try to use MSI-X or MSI if supported */
        if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
                return 0;

intx_irq:
        /* fall back to INTX IRQ */
        ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_INTX);
        if (ret < 0)
                return -ENODEV;

        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
                irqs[i] = pci_irq_vector(dev, 0);

        return 0;
}

/**
 * get_port_device_capability - discover capabilities of a PCI Express port
 * @dev: PCI Express port to examine
 *
 * The capabilities are read from the port's PCI Express configuration registers
 * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
 * 7.9 - 7.11.
 *
 * Return value: Bitmask of discovered port capabilities
 */
static int get_port_device_capability(struct pci_dev *dev)
{
        struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
        int services = 0;

        if (dev->is_pciehp &&
            (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
             pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) &&
            (pcie_ports_native || host->native_pcie_hotplug)) {
                services |= PCIE_PORT_SERVICE_HP;

                /*
                 * Disable hot-plug interrupts in case they have been enabled
                 * by the BIOS and the hot-plug service driver won't be loaded
                 * to handle them.
                 */
                if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
                        pcie_capability_clear_word(dev, PCI_EXP_SLTCTL,
                                PCI_EXP_SLTCTL_CCIE | PCI_EXP_SLTCTL_HPIE);
        }

#ifdef CONFIG_PCIEAER
        if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
             pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
            dev->aer_cap && pci_aer_available() &&
            (pcie_ports_native || host->native_aer))
                services |= PCIE_PORT_SERVICE_AER;
#endif

        /* Root Ports and Root Complex Event Collectors may generate PMEs */
        if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
             pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
            (pcie_ports_native || host->native_pme)) {
                services |= PCIE_PORT_SERVICE_PME;

                /*
                 * Disable PME interrupt on this port in case it's been enabled
                 * by the BIOS (the PME service driver will enable it when
                 * necessary).
                 */
                pcie_pme_interrupt_enable(dev, false);
        }

        /*
         * With dpc-native, allow Linux to use DPC even if it doesn't have
         * permission to use AER.
         */
        if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
            pci_aer_available() &&
            (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
                services |= PCIE_PORT_SERVICE_DPC;

        /* Enable bandwidth control if more than one speed is supported. */
        if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
            pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
                u32 linkcap;

                pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap);
                if (linkcap & PCI_EXP_LNKCAP_LBNC &&
                    hweight8(dev->supported_speeds) > 1)
                        services |= PCIE_PORT_SERVICE_BWCTRL;
        }

        return services;
}

/**
 * pcie_device_init - allocate and initialize PCI Express port service device
 * @pdev: PCI Express port to associate the service device with
 * @service: Type of service to associate with the service device
 * @irq: Interrupt vector to associate with the service device
 */
static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
{
        int retval;
        struct pcie_device *pcie;
        struct device *device;

        pcie = kzalloc_obj(*pcie);
        if (!pcie)
                return -ENOMEM;
        pcie->port = pdev;
        pcie->irq = irq;
        pcie->service = service;

        /* Initialize generic device interface */
        device = &pcie->device;
        device->bus = &pcie_port_bus_type;
        device->release = release_pcie_device;  /* callback to free pcie dev */
        dev_set_name(device, "%s:pcie%03x",
                     pci_name(pdev),
                     get_descriptor_id(pci_pcie_type(pdev), service));
        device->parent = &pdev->dev;
        device_enable_async_suspend(device);

        retval = device_register(device);
        if (retval) {
                put_device(device);
                return retval;
        }

        pm_runtime_no_callbacks(device);

        return 0;
}

/**
 * pcie_port_device_register - register PCI Express port
 * @dev: PCI Express port to register
 *
 * Allocate the port extension structure and register services associated with
 * the port.
 */
static int pcie_port_device_register(struct pci_dev *dev)
{
        int status, capabilities, i, nr_service;
        int irqs[PCIE_PORT_DEVICE_MAXSERVICES];

        /* Enable PCI Express port device */
        status = pci_enable_device(dev);
        if (status)
                return status;

        /* Get and check PCI Express port services */
        capabilities = get_port_device_capability(dev);
        if (!capabilities)
                return 0;

        pci_set_master(dev);
        /*
         * Initialize service irqs. Don't use service devices that
         * require interrupts if there is no way to generate them.
         * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
         * that can be used in the absence of irqs.  Allow them to determine
         * if that is to be used.
         */
        status = pcie_init_service_irqs(dev, irqs, capabilities);
        if (status) {
                capabilities &= PCIE_PORT_SERVICE_HP;
                if (!capabilities)
                        goto error_disable;
        }

        /* Allocate child services if any */
        status = -ENODEV;
        nr_service = 0;
        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
                int service = 1 << i;
                if (!(capabilities & service))
                        continue;
                if (!pcie_device_init(dev, service, irqs[i]))
                        nr_service++;
        }
        if (!nr_service)
                goto error_cleanup_irqs;

        return 0;

error_cleanup_irqs:
        pci_free_irq_vectors(dev);
error_disable:
        pci_disable_device(dev);
        return status;
}

typedef int (*pcie_callback_t)(struct pcie_device *);

static int pcie_port_device_iter(struct device *dev, void *data)
{
        struct pcie_port_service_driver *service_driver;
        size_t offset = *(size_t *)data;
        pcie_callback_t cb;

        if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
                service_driver = to_service_driver(dev->driver);
                cb = *(pcie_callback_t *)((void *)service_driver + offset);
                if (cb)
                        return cb(to_pcie_device(dev));
        }
        return 0;
}

#ifdef CONFIG_PM
/**
 * pcie_port_device_suspend - suspend port services associated with a PCIe port
 * @dev: PCI Express port to handle
 */
static int pcie_port_device_suspend(struct device *dev)
{
        size_t off = offsetof(struct pcie_port_service_driver, suspend);
        return device_for_each_child(dev, &off, pcie_port_device_iter);
}

static int pcie_port_device_resume_noirq(struct device *dev)
{
        size_t off = offsetof(struct pcie_port_service_driver, resume_noirq);
        return device_for_each_child(dev, &off, pcie_port_device_iter);
}

/**
 * pcie_port_device_resume - resume port services associated with a PCIe port
 * @dev: PCI Express port to handle
 */
static int pcie_port_device_resume(struct device *dev)
{
        size_t off = offsetof(struct pcie_port_service_driver, resume);
        return device_for_each_child(dev, &off, pcie_port_device_iter);
}

/**
 * pcie_port_device_runtime_suspend - runtime suspend port services
 * @dev: PCI Express port to handle
 */
static int pcie_port_device_runtime_suspend(struct device *dev)
{
        size_t off = offsetof(struct pcie_port_service_driver, runtime_suspend);
        return device_for_each_child(dev, &off, pcie_port_device_iter);
}

/**
 * pcie_port_device_runtime_resume - runtime resume port services
 * @dev: PCI Express port to handle
 */
static int pcie_port_device_runtime_resume(struct device *dev)
{
        size_t off = offsetof(struct pcie_port_service_driver, runtime_resume);
        return device_for_each_child(dev, &off, pcie_port_device_iter);
}
#endif /* PM */

static int remove_iter(struct device *dev, void *data)
{
        if (dev->bus == &pcie_port_bus_type)
                device_unregister(dev);
        return 0;
}

static int find_service_iter(struct device *device, void *data)
{
        struct pcie_port_service_driver *service_driver;
        struct portdrv_service_data *pdrvs;
        u32 service;

        pdrvs = (struct portdrv_service_data *) data;
        service = pdrvs->service;

        if (device->bus == &pcie_port_bus_type && device->driver) {
                service_driver = to_service_driver(device->driver);
                if (service_driver->service == service) {
                        pdrvs->drv = service_driver;
                        pdrvs->dev = device;
                        return 1;
                }
        }

        return 0;
}

/**
 * pcie_port_find_device - find the struct device
 * @dev: PCI Express port the service is associated with
 * @service: For the service to find
 *
 * Find the struct device associated with given service on a pci_dev
 */
struct device *pcie_port_find_device(struct pci_dev *dev,
                                      u32 service)
{
        struct device *device;
        struct portdrv_service_data pdrvs;

        pdrvs.dev = NULL;
        pdrvs.service = service;
        device_for_each_child(&dev->dev, &pdrvs, find_service_iter);

        device = pdrvs.dev;
        return device;
}
EXPORT_SYMBOL_GPL(pcie_port_find_device);

/**
 * pcie_port_device_remove - unregister PCI Express port service devices
 * @dev: PCI Express port the service devices to unregister are associated with
 *
 * Remove PCI Express port service devices associated with given port and
 * disable MSI-X or MSI for the port.
 */
static void pcie_port_device_remove(struct pci_dev *dev)
{
        device_for_each_child(&dev->dev, NULL, remove_iter);
        pci_free_irq_vectors(dev);
}

static int pcie_port_bus_match(struct device *dev, const struct device_driver *drv)
{
        struct pcie_device *pciedev = to_pcie_device(dev);
        const struct pcie_port_service_driver *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;
}

/**
 * pcie_port_bus_probe - probe driver for given PCI Express port service
 * @dev: PCI Express port service device to probe against
 *
 * If PCI Express port service driver is registered with
 * pcie_port_service_register(), this function will be called by the driver core
 * whenever match is found between the driver and a port service device.
 */
static int pcie_port_bus_probe(struct device *dev)
{
        struct pcie_device *pciedev;
        struct pcie_port_service_driver *driver;
        int status;

        driver = to_service_driver(dev->driver);
        if (!driver || !driver->probe)
                return -ENODEV;

        pciedev = to_pcie_device(dev);
        status = driver->probe(pciedev);
        if (status)
                return status;

        get_device(dev);
        return 0;
}

/**
 * pcie_port_bus_remove - detach driver from given PCI Express port service
 * @dev: PCI Express port service device to handle
 *
 * If PCI Express port service driver is registered with
 * pcie_port_service_register(), this function will be called by the driver core
 * when device_unregister() is called for the port service device associated
 * with the driver.
 */
static void pcie_port_bus_remove(struct device *dev)
{
        struct pcie_device *pciedev;
        struct pcie_port_service_driver *driver;

        pciedev = to_pcie_device(dev);
        driver = to_service_driver(dev->driver);
        if (driver && driver->remove)
                driver->remove(pciedev);

        put_device(dev);
}

const struct bus_type pcie_port_bus_type = {
        .name = "pci_express",
        .match = pcie_port_bus_match,
        .probe = pcie_port_bus_probe,
        .remove = pcie_port_bus_remove,
};

/**
 * pcie_port_service_register - register PCI Express port service driver
 * @new: PCI Express port service driver to register
 */
int pcie_port_service_register(struct pcie_port_service_driver *new)
{
        if (pcie_ports_disabled)
                return -ENODEV;

        new->driver.name = new->name;
        new->driver.bus = &pcie_port_bus_type;

        return driver_register(&new->driver);
}

/**
 * pcie_port_service_unregister - unregister PCI Express port service driver
 * @drv: PCI Express port service driver to unregister
 */
void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
{
        driver_unregister(&drv->driver);
}

/* If this switch is set, PCIe port native services should not be enabled. */
bool pcie_ports_disabled;

/*
 * If the user specified "pcie_ports=native", use the PCIe services regardless
 * of whether the platform has given us permission.  On ACPI systems, this
 * means we ignore _OSC.
 */
bool pcie_ports_native;

/*
 * If the user specified "pcie_ports=dpc-native", use the Linux DPC PCIe
 * service even if the platform hasn't given us permission.
 */
bool pcie_ports_dpc_native;

static int __init pcie_port_setup(char *str)
{
        if (!strncmp(str, "compat", 6))
                pcie_ports_disabled = true;
        else if (!strncmp(str, "native", 6))
                pcie_ports_native = true;
        else if (!strncmp(str, "dpc-native", 10))
                pcie_ports_dpc_native = true;

        return 1;
}
__setup("pcie_ports=", pcie_port_setup);

/* global data */

#ifdef CONFIG_PM
static int pcie_port_runtime_suspend(struct device *dev)
{
        if (!to_pci_dev(dev)->bridge_d3)
                return -EBUSY;

        return pcie_port_device_runtime_suspend(dev);
}

static int pcie_port_runtime_idle(struct device *dev)
{
        /*
         * Assume the PCI core has set bridge_d3 whenever it thinks the port
         * should be good to go to D3.  Everything else, including moving
         * the port to D3, is handled by the PCI core.
         */
        return to_pci_dev(dev)->bridge_d3 ? 0 : -EBUSY;
}

static const struct dev_pm_ops pcie_portdrv_pm_ops = {
        .suspend        = pcie_port_device_suspend,
        .resume_noirq   = pcie_port_device_resume_noirq,
        .resume         = pcie_port_device_resume,
        .freeze         = pcie_port_device_suspend,
        .thaw           = pcie_port_device_resume,
        .poweroff       = pcie_port_device_suspend,
        .restore_noirq  = pcie_port_device_resume_noirq,
        .restore        = pcie_port_device_resume,
        .runtime_suspend = pcie_port_runtime_suspend,
        .runtime_resume = pcie_port_device_runtime_resume,
        .runtime_idle   = pcie_port_runtime_idle,
};

#define PCIE_PORTDRV_PM_OPS     (&pcie_portdrv_pm_ops)

#else /* !PM */

#define PCIE_PORTDRV_PM_OPS     NULL
#endif /* !PM */

/*
 * pcie_portdrv_probe - Probe PCI-Express port devices
 * @dev: PCI-Express port device being probed
 *
 * If detected invokes the pcie_port_device_register() method for
 * this port device.
 *
 */
static int pcie_portdrv_probe(struct pci_dev *dev,
                                        const struct pci_device_id *id)
{
        int type = pci_pcie_type(dev);
        int status;

        if (!pci_is_pcie(dev) ||
            ((type != PCI_EXP_TYPE_ROOT_PORT) &&
             (type != PCI_EXP_TYPE_UPSTREAM) &&
             (type != PCI_EXP_TYPE_DOWNSTREAM) &&
             (type != PCI_EXP_TYPE_RC_EC)))
                return -ENODEV;

        if (type == PCI_EXP_TYPE_RC_EC)
                pcie_link_rcec(dev);

        status = pcie_port_device_register(dev);
        if (status)
                return status;

        pci_save_state(dev);

        dev_pm_set_driver_flags(&dev->dev, DPM_FLAG_NO_DIRECT_COMPLETE |
                                           DPM_FLAG_SMART_SUSPEND);

        if (pci_bridge_d3_possible(dev)) {
                /*
                 * Keep the port resumed 100ms to make sure things like
                 * config space accesses from userspace (lspci) will not
                 * cause the port to repeatedly suspend and resume.
                 */
                pm_runtime_set_autosuspend_delay(&dev->dev, 100);
                pm_runtime_use_autosuspend(&dev->dev);
                pm_runtime_mark_last_busy(&dev->dev);
                pm_runtime_put_autosuspend(&dev->dev);
                pm_runtime_allow(&dev->dev);
        }

        return 0;
}

static void pcie_portdrv_remove(struct pci_dev *dev)
{
        if (pci_bridge_d3_possible(dev)) {
                pm_runtime_forbid(&dev->dev);
                pm_runtime_get_noresume(&dev->dev);
                pm_runtime_dont_use_autosuspend(&dev->dev);
        }

        pcie_port_device_remove(dev);

        pci_disable_device(dev);
}

static void pcie_portdrv_shutdown(struct pci_dev *dev)
{
        if (pci_bridge_d3_possible(dev)) {
                pm_runtime_forbid(&dev->dev);
                pm_runtime_get_noresume(&dev->dev);
                pm_runtime_dont_use_autosuspend(&dev->dev);
        }

        pcie_port_device_remove(dev);
}

static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
                                        pci_channel_state_t error)
{
        if (error == pci_channel_io_frozen)
                return PCI_ERS_RESULT_NEED_RESET;
        return PCI_ERS_RESULT_CAN_RECOVER;
}

static pci_ers_result_t pcie_portdrv_slot_reset(struct pci_dev *dev)
{
        size_t off = offsetof(struct pcie_port_service_driver, slot_reset);
        device_for_each_child(&dev->dev, &off, pcie_port_device_iter);

        pci_restore_state(dev);
        return PCI_ERS_RESULT_RECOVERED;
}

static pci_ers_result_t pcie_portdrv_mmio_enabled(struct pci_dev *dev)
{
        return PCI_ERS_RESULT_RECOVERED;
}

/*
 * LINUX Device Driver Model
 */
static const struct pci_device_id port_pci_ids[] = {
        /* handle any PCI-Express port */
        { PCI_DEVICE_CLASS(PCI_CLASS_BRIDGE_PCI_NORMAL, ~0) },
        /* subtractive decode PCI-to-PCI bridge, class type is 060401h */
        { PCI_DEVICE_CLASS(PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE, ~0) },
        /* handle any Root Complex Event Collector */
        { PCI_DEVICE_CLASS(((PCI_CLASS_SYSTEM_RCEC << 8) | 0x00), ~0) },
        { },
};

static const struct pci_error_handlers pcie_portdrv_err_handler = {
        .error_detected = pcie_portdrv_error_detected,
        .slot_reset = pcie_portdrv_slot_reset,
        .mmio_enabled = pcie_portdrv_mmio_enabled,
};

static struct pci_driver pcie_portdriver = {
        .name           = "pcieport",
        .id_table       = port_pci_ids,

        .probe          = pcie_portdrv_probe,
        .remove         = pcie_portdrv_remove,
        .shutdown       = pcie_portdrv_shutdown,

        .err_handler    = &pcie_portdrv_err_handler,

        .driver_managed_dma = true,

        .driver.pm      = PCIE_PORTDRV_PM_OPS,
};

static int __init dmi_pcie_pme_disable_msi(const struct dmi_system_id *d)
{
        pr_notice("%s detected: will not use MSI for PCIe PME signaling\n",
                  d->ident);
        pcie_pme_disable_msi();
        return 0;
}

static const struct dmi_system_id pcie_portdrv_dmi_table[] __initconst = {
        /*
         * Boxes that should not use MSI for PCIe PME signaling.
         */
        {
         .callback = dmi_pcie_pme_disable_msi,
         .ident = "MSI Wind U-100",
         .matches = {
                     DMI_MATCH(DMI_SYS_VENDOR,
                                "MICRO-STAR INTERNATIONAL CO., LTD"),
                     DMI_MATCH(DMI_PRODUCT_NAME, "U-100"),
                     },
         },
         {}
};

static void __init pcie_init_services(void)
{
        pcie_aer_init();
        pcie_pme_init();
        pcie_dpc_init();
        pcie_bwctrl_init();
        pcie_hp_init();
}

static int __init pcie_portdrv_init(void)
{
        if (pcie_ports_disabled)
                return -EACCES;

        pcie_init_services();
        dmi_check_system(pcie_portdrv_dmi_table);

        return pci_register_driver(&pcie_portdriver);
}
device_initcall(pcie_portdrv_init);