gpio: rcar: Fix runtime PM imbalance on error

[linux/fpc-iii.git] / drivers / pci / pcie / aer.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Implement the AER root port service driver. The driver registers an IRQ
 * handler. When a root port triggers an AER interrupt, the IRQ handler
 * collects root port status and schedules work.
 *
 * Copyright (C) 2006 Intel Corp.
 *      Tom Long Nguyen (tom.l.nguyen@intel.com)
 *      Zhang Yanmin (yanmin.zhang@intel.com)
 *
 * (C) Copyright 2009 Hewlett-Packard Development Company, L.P.
 *    Andrew Patterson <andrew.patterson@hp.com>
 */

#define pr_fmt(fmt) "AER: " fmt
#define dev_fmt pr_fmt

#include <linux/bitops.h>
#include <linux/cper.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/kfifo.h>
#include <linux/slab.h>
#include <acpi/apei.h>
#include <ras/ras_event.h>

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

#define AER_ERROR_SOURCES_MAX           128

#define AER_MAX_TYPEOF_COR_ERRS         16      /* as per PCI_ERR_COR_STATUS */
#define AER_MAX_TYPEOF_UNCOR_ERRS       27      /* as per PCI_ERR_UNCOR_STATUS*/

struct aer_err_source {
        unsigned int status;
        unsigned int id;
};

struct aer_rpc {
        struct pci_dev *rpd;            /* Root Port device */
        DECLARE_KFIFO(aer_fifo, struct aer_err_source, AER_ERROR_SOURCES_MAX);
};

/* AER stats for the device */
struct aer_stats {

        /*
         * Fields for all AER capable devices. They indicate the errors
         * "as seen by this device". Note that this may mean that if an
         * end point is causing problems, the AER counters may increment
         * at its link partner (e.g. root port) because the errors will be
         * "seen" by the link partner and not the the problematic end point
         * itself (which may report all counters as 0 as it never saw any
         * problems).
         */
        /* Counters for different type of correctable errors */
        u64 dev_cor_errs[AER_MAX_TYPEOF_COR_ERRS];
        /* Counters for different type of fatal uncorrectable errors */
        u64 dev_fatal_errs[AER_MAX_TYPEOF_UNCOR_ERRS];
        /* Counters for different type of nonfatal uncorrectable errors */
        u64 dev_nonfatal_errs[AER_MAX_TYPEOF_UNCOR_ERRS];
        /* Total number of ERR_COR sent by this device */
        u64 dev_total_cor_errs;
        /* Total number of ERR_FATAL sent by this device */
        u64 dev_total_fatal_errs;
        /* Total number of ERR_NONFATAL sent by this device */
        u64 dev_total_nonfatal_errs;

        /*
         * Fields for Root ports & root complex event collectors only, these
         * indicate the total number of ERR_COR, ERR_FATAL, and ERR_NONFATAL
         * messages received by the root port / event collector, INCLUDING the
         * ones that are generated internally (by the rootport itself)
         */
        u64 rootport_total_cor_errs;
        u64 rootport_total_fatal_errs;
        u64 rootport_total_nonfatal_errs;
};

#define AER_LOG_TLP_MASKS               (PCI_ERR_UNC_POISON_TLP|        \
                                        PCI_ERR_UNC_ECRC|               \
                                        PCI_ERR_UNC_UNSUP|              \
                                        PCI_ERR_UNC_COMP_ABORT|         \
                                        PCI_ERR_UNC_UNX_COMP|           \
                                        PCI_ERR_UNC_MALF_TLP)

#define SYSTEM_ERROR_INTR_ON_MESG_MASK  (PCI_EXP_RTCTL_SECEE|   \
                                        PCI_EXP_RTCTL_SENFEE|   \
                                        PCI_EXP_RTCTL_SEFEE)
#define ROOT_PORT_INTR_ON_MESG_MASK     (PCI_ERR_ROOT_CMD_COR_EN|       \
                                        PCI_ERR_ROOT_CMD_NONFATAL_EN|   \
                                        PCI_ERR_ROOT_CMD_FATAL_EN)
#define ERR_COR_ID(d)                   (d & 0xffff)
#define ERR_UNCOR_ID(d)                 (d >> 16)

static int pcie_aer_disable;
static pci_ers_result_t aer_root_reset(struct pci_dev *dev);

void pci_no_aer(void)
{
        pcie_aer_disable = 1;
}

bool pci_aer_available(void)
{
        return !pcie_aer_disable && pci_msi_enabled();
}

#ifdef CONFIG_PCIE_ECRC

#define ECRC_POLICY_DEFAULT 0           /* ECRC set by BIOS */
#define ECRC_POLICY_OFF     1           /* ECRC off for performance */
#define ECRC_POLICY_ON      2           /* ECRC on for data integrity */

static int ecrc_policy = ECRC_POLICY_DEFAULT;

static const char * const ecrc_policy_str[] = {
        [ECRC_POLICY_DEFAULT] = "bios",
        [ECRC_POLICY_OFF] = "off",
        [ECRC_POLICY_ON] = "on"
};

/**
 * enable_ercr_checking - enable PCIe ECRC checking for a device
 * @dev: the PCI device
 *
 * Returns 0 on success, or negative on failure.
 */
static int enable_ecrc_checking(struct pci_dev *dev)
{
        int pos;
        u32 reg32;

        if (!pci_is_pcie(dev))
                return -ENODEV;

        pos = dev->aer_cap;
        if (!pos)
                return -ENODEV;

        pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
        if (reg32 & PCI_ERR_CAP_ECRC_GENC)
                reg32 |= PCI_ERR_CAP_ECRC_GENE;
        if (reg32 & PCI_ERR_CAP_ECRC_CHKC)
                reg32 |= PCI_ERR_CAP_ECRC_CHKE;
        pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);

        return 0;
}

/**
 * disable_ercr_checking - disables PCIe ECRC checking for a device
 * @dev: the PCI device
 *
 * Returns 0 on success, or negative on failure.
 */
static int disable_ecrc_checking(struct pci_dev *dev)
{
        int pos;
        u32 reg32;

        if (!pci_is_pcie(dev))
                return -ENODEV;

        pos = dev->aer_cap;
        if (!pos)
                return -ENODEV;

        pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
        reg32 &= ~(PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE);
        pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);

        return 0;
}

/**
 * pcie_set_ecrc_checking - set/unset PCIe ECRC checking for a device based on global policy
 * @dev: the PCI device
 */
void pcie_set_ecrc_checking(struct pci_dev *dev)
{
        switch (ecrc_policy) {
        case ECRC_POLICY_DEFAULT:
                return;
        case ECRC_POLICY_OFF:
                disable_ecrc_checking(dev);
                break;
        case ECRC_POLICY_ON:
                enable_ecrc_checking(dev);
                break;
        default:
                return;
        }
}

/**
 * pcie_ecrc_get_policy - parse kernel command-line ecrc option
 * @str: ECRC policy from kernel command line to use
 */
void pcie_ecrc_get_policy(char *str)
{
        int i;

        i = match_string(ecrc_policy_str, ARRAY_SIZE(ecrc_policy_str), str);
        if (i < 0)
                return;

        ecrc_policy = i;
}
#endif  /* CONFIG_PCIE_ECRC */

#ifdef CONFIG_ACPI_APEI
static inline int hest_match_pci(struct acpi_hest_aer_common *p,
                                 struct pci_dev *pci)
{
        return   ACPI_HEST_SEGMENT(p->bus) == pci_domain_nr(pci->bus) &&
                 ACPI_HEST_BUS(p->bus)     == pci->bus->number &&
                 p->device                 == PCI_SLOT(pci->devfn) &&
                 p->function               == PCI_FUNC(pci->devfn);
}

static inline bool hest_match_type(struct acpi_hest_header *hest_hdr,
                                struct pci_dev *dev)
{
        u16 hest_type = hest_hdr->type;
        u8 pcie_type = pci_pcie_type(dev);

        if ((hest_type == ACPI_HEST_TYPE_AER_ROOT_PORT &&
                pcie_type == PCI_EXP_TYPE_ROOT_PORT) ||
            (hest_type == ACPI_HEST_TYPE_AER_ENDPOINT &&
                pcie_type == PCI_EXP_TYPE_ENDPOINT) ||
            (hest_type == ACPI_HEST_TYPE_AER_BRIDGE &&
                (dev->class >> 16) == PCI_BASE_CLASS_BRIDGE))
                return true;
        return false;
}

struct aer_hest_parse_info {
        struct pci_dev *pci_dev;
        int firmware_first;
};

static int hest_source_is_pcie_aer(struct acpi_hest_header *hest_hdr)
{
        if (hest_hdr->type == ACPI_HEST_TYPE_AER_ROOT_PORT ||
            hest_hdr->type == ACPI_HEST_TYPE_AER_ENDPOINT ||
            hest_hdr->type == ACPI_HEST_TYPE_AER_BRIDGE)
                return 1;
        return 0;
}

static int aer_hest_parse(struct acpi_hest_header *hest_hdr, void *data)
{
        struct aer_hest_parse_info *info = data;
        struct acpi_hest_aer_common *p;
        int ff;

        if (!hest_source_is_pcie_aer(hest_hdr))
                return 0;

        p = (struct acpi_hest_aer_common *)(hest_hdr + 1);
        ff = !!(p->flags & ACPI_HEST_FIRMWARE_FIRST);

        /*
         * If no specific device is supplied, determine whether
         * FIRMWARE_FIRST is set for *any* PCIe device.
         */
        if (!info->pci_dev) {
                info->firmware_first |= ff;
                return 0;
        }

        /* Otherwise, check the specific device */
        if (p->flags & ACPI_HEST_GLOBAL) {
                if (hest_match_type(hest_hdr, info->pci_dev))
                        info->firmware_first = ff;
        } else
                if (hest_match_pci(p, info->pci_dev))
                        info->firmware_first = ff;

        return 0;
}

static void aer_set_firmware_first(struct pci_dev *pci_dev)
{
        int rc;
        struct aer_hest_parse_info info = {
                .pci_dev        = pci_dev,
                .firmware_first = 0,
        };

        rc = apei_hest_parse(aer_hest_parse, &info);

        if (rc)
                pci_dev->__aer_firmware_first = 0;
        else
                pci_dev->__aer_firmware_first = info.firmware_first;
        pci_dev->__aer_firmware_first_valid = 1;
}

int pcie_aer_get_firmware_first(struct pci_dev *dev)
{
        if (!pci_is_pcie(dev))
                return 0;

        if (pcie_ports_native)
                return 0;

        if (!dev->__aer_firmware_first_valid)
                aer_set_firmware_first(dev);
        return dev->__aer_firmware_first;
}

static bool aer_firmware_first;

/**
 * aer_acpi_firmware_first - Check if APEI should control AER.
 */
bool aer_acpi_firmware_first(void)
{
        static bool parsed = false;
        struct aer_hest_parse_info info = {
                .pci_dev        = NULL, /* Check all PCIe devices */
                .firmware_first = 0,
        };

        if (pcie_ports_native)
                return false;

        if (!parsed) {
                apei_hest_parse(aer_hest_parse, &info);
                aer_firmware_first = info.firmware_first;
                parsed = true;
        }
        return aer_firmware_first;
}
#endif

#define PCI_EXP_AER_FLAGS       (PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE | \
                                 PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE)

int pci_enable_pcie_error_reporting(struct pci_dev *dev)
{
        if (pcie_aer_get_firmware_first(dev))
                return -EIO;

        if (!dev->aer_cap)
                return -EIO;

        return pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_AER_FLAGS);
}
EXPORT_SYMBOL_GPL(pci_enable_pcie_error_reporting);

int pci_disable_pcie_error_reporting(struct pci_dev *dev)
{
        if (pcie_aer_get_firmware_first(dev))
                return -EIO;

        return pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
                                          PCI_EXP_AER_FLAGS);
}
EXPORT_SYMBOL_GPL(pci_disable_pcie_error_reporting);

void pci_aer_clear_device_status(struct pci_dev *dev)
{
        u16 sta;

        pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &sta);
        pcie_capability_write_word(dev, PCI_EXP_DEVSTA, sta);
}

int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
{
        int pos;
        u32 status, sev;

        pos = dev->aer_cap;
        if (!pos)
                return -EIO;

        if (pcie_aer_get_firmware_first(dev))
                return -EIO;

        /* Clear status bits for ERR_NONFATAL errors only */
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, &sev);
        status &= ~sev;
        if (status)
                pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);

        return 0;
}
EXPORT_SYMBOL_GPL(pci_aer_clear_nonfatal_status);

void pci_aer_clear_fatal_status(struct pci_dev *dev)
{
        int pos;
        u32 status, sev;

        pos = dev->aer_cap;
        if (!pos)
                return;

        if (pcie_aer_get_firmware_first(dev))
                return;

        /* Clear status bits for ERR_FATAL errors only */
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, &sev);
        status &= sev;
        if (status)
                pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);
}

/**
 * pci_aer_raw_clear_status - Clear AER error registers.
 * @dev: the PCI device
 *
 * Clearing AER error status registers unconditionally, regardless of
 * whether they're owned by firmware or the OS.
 *
 * Returns 0 on success, or negative on failure.
 */
int pci_aer_raw_clear_status(struct pci_dev *dev)
{
        int pos;
        u32 status;
        int port_type;

        if (!pci_is_pcie(dev))
                return -ENODEV;

        pos = dev->aer_cap;
        if (!pos)
                return -EIO;

        port_type = pci_pcie_type(dev);
        if (port_type == PCI_EXP_TYPE_ROOT_PORT) {
                pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &status);
                pci_write_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, status);
        }

        pci_read_config_dword(dev, pos + PCI_ERR_COR_STATUS, &status);
        pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS, status);

        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
        pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);

        return 0;
}

int pci_aer_clear_status(struct pci_dev *dev)
{
        if (pcie_aer_get_firmware_first(dev))
                return -EIO;

        return pci_aer_raw_clear_status(dev);
}

void pci_save_aer_state(struct pci_dev *dev)
{
        struct pci_cap_saved_state *save_state;
        u32 *cap;
        int pos;

        pos = dev->aer_cap;
        if (!pos)
                return;

        save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
        if (!save_state)
                return;

        cap = &save_state->cap.data[0];
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, cap++);
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, cap++);
        pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, cap++);
        pci_read_config_dword(dev, pos + PCI_ERR_CAP, cap++);
        if (pcie_cap_has_rtctl(dev))
                pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, cap++);
}

void pci_restore_aer_state(struct pci_dev *dev)
{
        struct pci_cap_saved_state *save_state;
        u32 *cap;
        int pos;

        pos = dev->aer_cap;
        if (!pos)
                return;

        save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
        if (!save_state)
                return;

        cap = &save_state->cap.data[0];
        pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, *cap++);
        pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, *cap++);
        pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, *cap++);
        pci_write_config_dword(dev, pos + PCI_ERR_CAP, *cap++);
        if (pcie_cap_has_rtctl(dev))
                pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, *cap++);
}

void pci_aer_init(struct pci_dev *dev)
{
        int n;

        dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
        if (!dev->aer_cap)
                return;

        dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);

        /*
         * We save/restore PCI_ERR_UNCOR_MASK, PCI_ERR_UNCOR_SEVER,
         * PCI_ERR_COR_MASK, and PCI_ERR_CAP.  Root and Root Complex Event
         * Collectors also implement PCI_ERR_ROOT_COMMAND (PCIe r5.0, sec
         * 7.8.4).
         */
        n = pcie_cap_has_rtctl(dev) ? 5 : 4;
        pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR, sizeof(u32) * n);

        pci_aer_clear_status(dev);
}

void pci_aer_exit(struct pci_dev *dev)
{
        kfree(dev->aer_stats);
        dev->aer_stats = NULL;
}

#define AER_AGENT_RECEIVER              0
#define AER_AGENT_REQUESTER             1
#define AER_AGENT_COMPLETER             2
#define AER_AGENT_TRANSMITTER           3

#define AER_AGENT_REQUESTER_MASK(t)     ((t == AER_CORRECTABLE) ?       \
        0 : (PCI_ERR_UNC_COMP_TIME|PCI_ERR_UNC_UNSUP))
#define AER_AGENT_COMPLETER_MASK(t)     ((t == AER_CORRECTABLE) ?       \
        0 : PCI_ERR_UNC_COMP_ABORT)
#define AER_AGENT_TRANSMITTER_MASK(t)   ((t == AER_CORRECTABLE) ?       \
        (PCI_ERR_COR_REP_ROLL|PCI_ERR_COR_REP_TIMER) : 0)

#define AER_GET_AGENT(t, e)                                             \
        ((e & AER_AGENT_COMPLETER_MASK(t)) ? AER_AGENT_COMPLETER :      \
        (e & AER_AGENT_REQUESTER_MASK(t)) ? AER_AGENT_REQUESTER :       \
        (e & AER_AGENT_TRANSMITTER_MASK(t)) ? AER_AGENT_TRANSMITTER :   \
        AER_AGENT_RECEIVER)

#define AER_PHYSICAL_LAYER_ERROR        0
#define AER_DATA_LINK_LAYER_ERROR       1
#define AER_TRANSACTION_LAYER_ERROR     2

#define AER_PHYSICAL_LAYER_ERROR_MASK(t) ((t == AER_CORRECTABLE) ?      \
        PCI_ERR_COR_RCVR : 0)
#define AER_DATA_LINK_LAYER_ERROR_MASK(t) ((t == AER_CORRECTABLE) ?     \
        (PCI_ERR_COR_BAD_TLP|                                           \
        PCI_ERR_COR_BAD_DLLP|                                           \
        PCI_ERR_COR_REP_ROLL|                                           \
        PCI_ERR_COR_REP_TIMER) : PCI_ERR_UNC_DLP)

#define AER_GET_LAYER_ERROR(t, e)                                       \
        ((e & AER_PHYSICAL_LAYER_ERROR_MASK(t)) ? AER_PHYSICAL_LAYER_ERROR : \
        (e & AER_DATA_LINK_LAYER_ERROR_MASK(t)) ? AER_DATA_LINK_LAYER_ERROR : \
        AER_TRANSACTION_LAYER_ERROR)

/*
 * AER error strings
 */
static const char *aer_error_severity_string[] = {
        "Uncorrected (Non-Fatal)",
        "Uncorrected (Fatal)",
        "Corrected"
};

static const char *aer_error_layer[] = {
        "Physical Layer",
        "Data Link Layer",
        "Transaction Layer"
};

static const char *aer_correctable_error_string[AER_MAX_TYPEOF_COR_ERRS] = {
        "RxErr",                        /* Bit Position 0       */
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        "BadTLP",                       /* Bit Position 6       */
        "BadDLLP",                      /* Bit Position 7       */
        "Rollover",                     /* Bit Position 8       */
        NULL,
        NULL,
        NULL,
        "Timeout",                      /* Bit Position 12      */
        "NonFatalErr",                  /* Bit Position 13      */
        "CorrIntErr",                   /* Bit Position 14      */
        "HeaderOF",                     /* Bit Position 15      */
};

static const char *aer_uncorrectable_error_string[AER_MAX_TYPEOF_UNCOR_ERRS] = {
        "Undefined",                    /* Bit Position 0       */
        NULL,
        NULL,
        NULL,
        "DLP",                          /* Bit Position 4       */
        "SDES",                         /* Bit Position 5       */
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        "TLP",                          /* Bit Position 12      */
        "FCP",                          /* Bit Position 13      */
        "CmpltTO",                      /* Bit Position 14      */
        "CmpltAbrt",                    /* Bit Position 15      */
        "UnxCmplt",                     /* Bit Position 16      */
        "RxOF",                         /* Bit Position 17      */
        "MalfTLP",                      /* Bit Position 18      */
        "ECRC",                         /* Bit Position 19      */
        "UnsupReq",                     /* Bit Position 20      */
        "ACSViol",                      /* Bit Position 21      */
        "UncorrIntErr",                 /* Bit Position 22      */
        "BlockedTLP",                   /* Bit Position 23      */
        "AtomicOpBlocked",              /* Bit Position 24      */
        "TLPBlockedErr",                /* Bit Position 25      */
        "PoisonTLPBlocked",             /* Bit Position 26      */
};

static const char *aer_agent_string[] = {
        "Receiver ID",
        "Requester ID",
        "Completer ID",
        "Transmitter ID"
};

#define aer_stats_dev_attr(name, stats_array, strings_array,            \
                           total_string, total_field)                   \
        static ssize_t                                                  \
        name##_show(struct device *dev, struct device_attribute *attr,  \
                     char *buf)                                         \
{                                                                       \
        unsigned int i;                                                 \
        char *str = buf;                                                \
        struct pci_dev *pdev = to_pci_dev(dev);                         \
        u64 *stats = pdev->aer_stats->stats_array;                      \
                                                                        \
        for (i = 0; i < ARRAY_SIZE(strings_array); i++) {               \
                if (strings_array[i])                                   \
                        str += sprintf(str, "%s %llu\n",                \
                                       strings_array[i], stats[i]);     \
                else if (stats[i])                                      \
                        str += sprintf(str, #stats_array "_bit[%d] %llu\n",\
                                       i, stats[i]);                    \
        }                                                               \
        str += sprintf(str, "TOTAL_%s %llu\n", total_string,            \
                       pdev->aer_stats->total_field);                   \
        return str-buf;                                                 \
}                                                                       \
static DEVICE_ATTR_RO(name)

aer_stats_dev_attr(aer_dev_correctable, dev_cor_errs,
                   aer_correctable_error_string, "ERR_COR",
                   dev_total_cor_errs);
aer_stats_dev_attr(aer_dev_fatal, dev_fatal_errs,
                   aer_uncorrectable_error_string, "ERR_FATAL",
                   dev_total_fatal_errs);
aer_stats_dev_attr(aer_dev_nonfatal, dev_nonfatal_errs,
                   aer_uncorrectable_error_string, "ERR_NONFATAL",
                   dev_total_nonfatal_errs);

#define aer_stats_rootport_attr(name, field)                            \
        static ssize_t                                                  \
        name##_show(struct device *dev, struct device_attribute *attr,  \
                     char *buf)                                         \
{                                                                       \
        struct pci_dev *pdev = to_pci_dev(dev);                         \
        return sprintf(buf, "%llu\n", pdev->aer_stats->field);          \
}                                                                       \
static DEVICE_ATTR_RO(name)

aer_stats_rootport_attr(aer_rootport_total_err_cor,
                         rootport_total_cor_errs);
aer_stats_rootport_attr(aer_rootport_total_err_fatal,
                         rootport_total_fatal_errs);
aer_stats_rootport_attr(aer_rootport_total_err_nonfatal,
                         rootport_total_nonfatal_errs);

static struct attribute *aer_stats_attrs[] __ro_after_init = {
        &dev_attr_aer_dev_correctable.attr,
        &dev_attr_aer_dev_fatal.attr,
        &dev_attr_aer_dev_nonfatal.attr,
        &dev_attr_aer_rootport_total_err_cor.attr,
        &dev_attr_aer_rootport_total_err_fatal.attr,
        &dev_attr_aer_rootport_total_err_nonfatal.attr,
        NULL
};

static umode_t aer_stats_attrs_are_visible(struct kobject *kobj,
                                           struct attribute *a, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);

        if (!pdev->aer_stats)
                return 0;

        if ((a == &dev_attr_aer_rootport_total_err_cor.attr ||
             a == &dev_attr_aer_rootport_total_err_fatal.attr ||
             a == &dev_attr_aer_rootport_total_err_nonfatal.attr) &&
            pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT)
                return 0;

        return a->mode;
}

const struct attribute_group aer_stats_attr_group = {
        .attrs  = aer_stats_attrs,
        .is_visible = aer_stats_attrs_are_visible,
};

static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
                                   struct aer_err_info *info)
{
        unsigned long status = info->status & ~info->mask;
        int i, max = -1;
        u64 *counter = NULL;
        struct aer_stats *aer_stats = pdev->aer_stats;

        if (!aer_stats)
                return;

        switch (info->severity) {
        case AER_CORRECTABLE:
                aer_stats->dev_total_cor_errs++;
                counter = &aer_stats->dev_cor_errs[0];
                max = AER_MAX_TYPEOF_COR_ERRS;
                break;
        case AER_NONFATAL:
                aer_stats->dev_total_nonfatal_errs++;
                counter = &aer_stats->dev_nonfatal_errs[0];
                max = AER_MAX_TYPEOF_UNCOR_ERRS;
                break;
        case AER_FATAL:
                aer_stats->dev_total_fatal_errs++;
                counter = &aer_stats->dev_fatal_errs[0];
                max = AER_MAX_TYPEOF_UNCOR_ERRS;
                break;
        }

        for_each_set_bit(i, &status, max)
                counter[i]++;
}

static void pci_rootport_aer_stats_incr(struct pci_dev *pdev,
                                 struct aer_err_source *e_src)
{
        struct aer_stats *aer_stats = pdev->aer_stats;

        if (!aer_stats)
                return;

        if (e_src->status & PCI_ERR_ROOT_COR_RCV)
                aer_stats->rootport_total_cor_errs++;

        if (e_src->status & PCI_ERR_ROOT_UNCOR_RCV) {
                if (e_src->status & PCI_ERR_ROOT_FATAL_RCV)
                        aer_stats->rootport_total_fatal_errs++;
                else
                        aer_stats->rootport_total_nonfatal_errs++;
        }
}

static void __print_tlp_header(struct pci_dev *dev,
                               struct aer_header_log_regs *t)
{
        pci_err(dev, "  TLP Header: %08x %08x %08x %08x\n",
                t->dw0, t->dw1, t->dw2, t->dw3);
}

static void __aer_print_error(struct pci_dev *dev,
                              struct aer_err_info *info)
{
        unsigned long status = info->status & ~info->mask;
        const char *errmsg = NULL;
        int i;

        for_each_set_bit(i, &status, 32) {
                if (info->severity == AER_CORRECTABLE)
                        errmsg = i < ARRAY_SIZE(aer_correctable_error_string) ?
                                aer_correctable_error_string[i] : NULL;
                else
                        errmsg = i < ARRAY_SIZE(aer_uncorrectable_error_string) ?
                                aer_uncorrectable_error_string[i] : NULL;

                if (errmsg)
                        pci_err(dev, "   [%2d] %-22s%s\n", i, errmsg,
                                info->first_error == i ? " (First)" : "");
                else
                        pci_err(dev, "   [%2d] Unknown Error Bit%s\n",
                                i, info->first_error == i ? " (First)" : "");
        }
        pci_dev_aer_stats_incr(dev, info);
}

void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
{
        int layer, agent;
        int id = ((dev->bus->number << 8) | dev->devfn);

        if (!info->status) {
                pci_err(dev, "PCIe Bus Error: severity=%s, type=Inaccessible, (Unregistered Agent ID)\n",
                        aer_error_severity_string[info->severity]);
                goto out;
        }

        layer = AER_GET_LAYER_ERROR(info->severity, info->status);
        agent = AER_GET_AGENT(info->severity, info->status);

        pci_err(dev, "PCIe Bus Error: severity=%s, type=%s, (%s)\n",
                aer_error_severity_string[info->severity],
                aer_error_layer[layer], aer_agent_string[agent]);

        pci_err(dev, "  device [%04x:%04x] error status/mask=%08x/%08x\n",
                dev->vendor, dev->device,
                info->status, info->mask);

        __aer_print_error(dev, info);

        if (info->tlp_header_valid)
                __print_tlp_header(dev, &info->tlp);

out:
        if (info->id && info->error_dev_num > 1 && info->id == id)
                pci_err(dev, "  Error of this Agent is reported first\n");

        trace_aer_event(dev_name(&dev->dev), (info->status & ~info->mask),
                        info->severity, info->tlp_header_valid, &info->tlp);
}

static void aer_print_port_info(struct pci_dev *dev, struct aer_err_info *info)
{
        u8 bus = info->id >> 8;
        u8 devfn = info->id & 0xff;

        pci_info(dev, "%s%s error received: %04x:%02x:%02x.%d\n",
                 info->multi_error_valid ? "Multiple " : "",
                 aer_error_severity_string[info->severity],
                 pci_domain_nr(dev->bus), bus, PCI_SLOT(devfn),
                 PCI_FUNC(devfn));
}

#ifdef CONFIG_ACPI_APEI_PCIEAER
int cper_severity_to_aer(int cper_severity)
{
        switch (cper_severity) {
        case CPER_SEV_RECOVERABLE:
                return AER_NONFATAL;
        case CPER_SEV_FATAL:
                return AER_FATAL;
        default:
                return AER_CORRECTABLE;
        }
}
EXPORT_SYMBOL_GPL(cper_severity_to_aer);

void cper_print_aer(struct pci_dev *dev, int aer_severity,
                    struct aer_capability_regs *aer)
{
        int layer, agent, tlp_header_valid = 0;
        u32 status, mask;
        struct aer_err_info info;

        if (aer_severity == AER_CORRECTABLE) {
                status = aer->cor_status;
                mask = aer->cor_mask;
        } else {
                status = aer->uncor_status;
                mask = aer->uncor_mask;
                tlp_header_valid = status & AER_LOG_TLP_MASKS;
        }

        layer = AER_GET_LAYER_ERROR(aer_severity, status);
        agent = AER_GET_AGENT(aer_severity, status);

        memset(&info, 0, sizeof(info));
        info.severity = aer_severity;
        info.status = status;
        info.mask = mask;
        info.first_error = PCI_ERR_CAP_FEP(aer->cap_control);

        pci_err(dev, "aer_status: 0x%08x, aer_mask: 0x%08x\n", status, mask);
        __aer_print_error(dev, &info);
        pci_err(dev, "aer_layer=%s, aer_agent=%s\n",
                aer_error_layer[layer], aer_agent_string[agent]);

        if (aer_severity != AER_CORRECTABLE)
                pci_err(dev, "aer_uncor_severity: 0x%08x\n",
                        aer->uncor_severity);

        if (tlp_header_valid)
                __print_tlp_header(dev, &aer->header_log);

        trace_aer_event(dev_name(&dev->dev), (status & ~mask),
                        aer_severity, tlp_header_valid, &aer->header_log);
}
#endif

/**
 * add_error_device - list device to be handled
 * @e_info: pointer to error info
 * @dev: pointer to pci_dev to be added
 */
static int add_error_device(struct aer_err_info *e_info, struct pci_dev *dev)
{
        if (e_info->error_dev_num < AER_MAX_MULTI_ERR_DEVICES) {
                e_info->dev[e_info->error_dev_num] = pci_dev_get(dev);
                e_info->error_dev_num++;
                return 0;
        }
        return -ENOSPC;
}

/**
 * is_error_source - check whether the device is source of reported error
 * @dev: pointer to pci_dev to be checked
 * @e_info: pointer to reported error info
 */
static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
{
        int pos;
        u32 status, mask;
        u16 reg16;

        /*
         * When bus id is equal to 0, it might be a bad id
         * reported by root port.
         */
        if ((PCI_BUS_NUM(e_info->id) != 0) &&
            !(dev->bus->bus_flags & PCI_BUS_FLAGS_NO_AERSID)) {
                /* Device ID match? */
                if (e_info->id == ((dev->bus->number << 8) | dev->devfn))
                        return true;

                /* Continue id comparing if there is no multiple error */
                if (!e_info->multi_error_valid)
                        return false;
        }

        /*
         * When either
         *      1) bus id is equal to 0. Some ports might lose the bus
         *              id of error source id;
         *      2) bus flag PCI_BUS_FLAGS_NO_AERSID is set
         *      3) There are multiple errors and prior ID comparing fails;
         * We check AER status registers to find possible reporter.
         */
        if (atomic_read(&dev->enable_cnt) == 0)
                return false;

        /* Check if AER is enabled */
        pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &reg16);
        if (!(reg16 & PCI_EXP_AER_FLAGS))
                return false;

        pos = dev->aer_cap;
        if (!pos)
                return false;

        /* Check if error is recorded */
        if (e_info->severity == AER_CORRECTABLE) {
                pci_read_config_dword(dev, pos + PCI_ERR_COR_STATUS, &status);
                pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, &mask);
        } else {
                pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
                pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, &mask);
        }
        if (status & ~mask)
                return true;

        return false;
}

static int find_device_iter(struct pci_dev *dev, void *data)
{
        struct aer_err_info *e_info = (struct aer_err_info *)data;

        if (is_error_source(dev, e_info)) {
                /* List this device */
                if (add_error_device(e_info, dev)) {
                        /* We cannot handle more... Stop iteration */
                        /* TODO: Should print error message here? */
                        return 1;
                }

                /* If there is only a single error, stop iteration */
                if (!e_info->multi_error_valid)
                        return 1;
        }
        return 0;
}

/**
 * find_source_device - search through device hierarchy for source device
 * @parent: pointer to Root Port pci_dev data structure
 * @e_info: including detailed error information such like id
 *
 * Return true if found.
 *
 * Invoked by DPC when error is detected at the Root Port.
 * Caller of this function must set id, severity, and multi_error_valid of
 * struct aer_err_info pointed by @e_info properly.  This function must fill
 * e_info->error_dev_num and e_info->dev[], based on the given information.
 */
static bool find_source_device(struct pci_dev *parent,
                struct aer_err_info *e_info)
{
        struct pci_dev *dev = parent;
        int result;

        /* Must reset in this function */
        e_info->error_dev_num = 0;

        /* Is Root Port an agent that sends error message? */
        result = find_device_iter(dev, e_info);
        if (result)
                return true;

        pci_walk_bus(parent->subordinate, find_device_iter, e_info);

        if (!e_info->error_dev_num) {
                pci_info(parent, "can't find device of ID%04x\n", e_info->id);
                return false;
        }
        return true;
}

/**
 * handle_error_source - handle logging error into an event log
 * @dev: pointer to pci_dev data structure of error source device
 * @info: comprehensive error information
 *
 * Invoked when an error being detected by Root Port.
 */
static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
{
        int pos;

        if (info->severity == AER_CORRECTABLE) {
                /*
                 * Correctable error does not need software intervention.
                 * No need to go through error recovery process.
                 */
                pos = dev->aer_cap;
                if (pos)
                        pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS,
                                        info->status);
                pci_aer_clear_device_status(dev);
        } else if (info->severity == AER_NONFATAL)
                pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
        else if (info->severity == AER_FATAL)
                pcie_do_recovery(dev, pci_channel_io_frozen, aer_root_reset);
        pci_dev_put(dev);
}

#ifdef CONFIG_ACPI_APEI_PCIEAER

#define AER_RECOVER_RING_ORDER          4
#define AER_RECOVER_RING_SIZE           (1 << AER_RECOVER_RING_ORDER)

struct aer_recover_entry {
        u8      bus;
        u8      devfn;
        u16     domain;
        int     severity;
        struct aer_capability_regs *regs;
};

static DEFINE_KFIFO(aer_recover_ring, struct aer_recover_entry,
                    AER_RECOVER_RING_SIZE);

static void aer_recover_work_func(struct work_struct *work)
{
        struct aer_recover_entry entry;
        struct pci_dev *pdev;

        while (kfifo_get(&aer_recover_ring, &entry)) {
                pdev = pci_get_domain_bus_and_slot(entry.domain, entry.bus,
                                                   entry.devfn);
                if (!pdev) {
                        pr_err("AER recover: Can not find pci_dev for %04x:%02x:%02x:%x\n",
                               entry.domain, entry.bus,
                               PCI_SLOT(entry.devfn), PCI_FUNC(entry.devfn));
                        continue;
                }
                cper_print_aer(pdev, entry.severity, entry.regs);
                if (entry.severity == AER_NONFATAL)
                        pcie_do_recovery(pdev, pci_channel_io_normal,
                                         aer_root_reset);
                else if (entry.severity == AER_FATAL)
                        pcie_do_recovery(pdev, pci_channel_io_frozen,
                                         aer_root_reset);
                pci_dev_put(pdev);
        }
}

/*
 * Mutual exclusion for writers of aer_recover_ring, reader side don't
 * need lock, because there is only one reader and lock is not needed
 * between reader and writer.
 */
static DEFINE_SPINLOCK(aer_recover_ring_lock);
static DECLARE_WORK(aer_recover_work, aer_recover_work_func);

void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
                       int severity, struct aer_capability_regs *aer_regs)
{
        struct aer_recover_entry entry = {
                .bus            = bus,
                .devfn          = devfn,
                .domain         = domain,
                .severity       = severity,
                .regs           = aer_regs,
        };

        if (kfifo_in_spinlocked(&aer_recover_ring, &entry, 1,
                                 &aer_recover_ring_lock))
                schedule_work(&aer_recover_work);
        else
                pr_err("AER recover: Buffer overflow when recovering AER for %04x:%02x:%02x:%x\n",
                       domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
}
EXPORT_SYMBOL_GPL(aer_recover_queue);
#endif

/**
 * aer_get_device_error_info - read error status from dev and store it to info
 * @dev: pointer to the device expected to have a error record
 * @info: pointer to structure to store the error record
 *
 * Return 1 on success, 0 on error.
 *
 * Note that @info is reused among all error devices. Clear fields properly.
 */
int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
{
        int pos, temp;

        /* Must reset in this function */
        info->status = 0;
        info->tlp_header_valid = 0;

        pos = dev->aer_cap;

        /* The device might not support AER */
        if (!pos)
                return 0;

        if (info->severity == AER_CORRECTABLE) {
                pci_read_config_dword(dev, pos + PCI_ERR_COR_STATUS,
                        &info->status);
                pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK,
                        &info->mask);
                if (!(info->status & ~info->mask))
                        return 0;
        } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
                   pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
                   info->severity == AER_NONFATAL) {

                /* Link is still healthy for IO reads */
                pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS,
                        &info->status);
                pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK,
                        &info->mask);
                if (!(info->status & ~info->mask))
                        return 0;

                /* Get First Error Pointer */
                pci_read_config_dword(dev, pos + PCI_ERR_CAP, &temp);
                info->first_error = PCI_ERR_CAP_FEP(temp);

                if (info->status & AER_LOG_TLP_MASKS) {
                        info->tlp_header_valid = 1;
                        pci_read_config_dword(dev,
                                pos + PCI_ERR_HEADER_LOG, &info->tlp.dw0);
                        pci_read_config_dword(dev,
                                pos + PCI_ERR_HEADER_LOG + 4, &info->tlp.dw1);
                        pci_read_config_dword(dev,
                                pos + PCI_ERR_HEADER_LOG + 8, &info->tlp.dw2);
                        pci_read_config_dword(dev,
                                pos + PCI_ERR_HEADER_LOG + 12, &info->tlp.dw3);
                }
        }

        return 1;
}

static inline void aer_process_err_devices(struct aer_err_info *e_info)
{
        int i;

        /* Report all before handle them, not to lost records by reset etc. */
        for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
                if (aer_get_device_error_info(e_info->dev[i], e_info))
                        aer_print_error(e_info->dev[i], e_info);
        }
        for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
                if (aer_get_device_error_info(e_info->dev[i], e_info))
                        handle_error_source(e_info->dev[i], e_info);
        }
}

/**
 * aer_isr_one_error - consume an error detected by root port
 * @rpc: pointer to the root port which holds an error
 * @e_src: pointer to an error source
 */
static void aer_isr_one_error(struct aer_rpc *rpc,
                struct aer_err_source *e_src)
{
        struct pci_dev *pdev = rpc->rpd;
        struct aer_err_info e_info;

        pci_rootport_aer_stats_incr(pdev, e_src);

        /*
         * There is a possibility that both correctable error and
         * uncorrectable error being logged. Report correctable error first.
         */
        if (e_src->status & PCI_ERR_ROOT_COR_RCV) {
                e_info.id = ERR_COR_ID(e_src->id);
                e_info.severity = AER_CORRECTABLE;

                if (e_src->status & PCI_ERR_ROOT_MULTI_COR_RCV)
                        e_info.multi_error_valid = 1;
                else
                        e_info.multi_error_valid = 0;
                aer_print_port_info(pdev, &e_info);

                if (find_source_device(pdev, &e_info))
                        aer_process_err_devices(&e_info);
        }

        if (e_src->status & PCI_ERR_ROOT_UNCOR_RCV) {
                e_info.id = ERR_UNCOR_ID(e_src->id);

                if (e_src->status & PCI_ERR_ROOT_FATAL_RCV)
                        e_info.severity = AER_FATAL;
                else
                        e_info.severity = AER_NONFATAL;

                if (e_src->status & PCI_ERR_ROOT_MULTI_UNCOR_RCV)
                        e_info.multi_error_valid = 1;
                else
                        e_info.multi_error_valid = 0;

                aer_print_port_info(pdev, &e_info);

                if (find_source_device(pdev, &e_info))
                        aer_process_err_devices(&e_info);
        }
}

/**
 * aer_isr - consume errors detected by root port
 * @irq: IRQ assigned to Root Port
 * @context: pointer to Root Port data structure
 *
 * Invoked, as DPC, when root port records new detected error
 */
static irqreturn_t aer_isr(int irq, void *context)
{
        struct pcie_device *dev = (struct pcie_device *)context;
        struct aer_rpc *rpc = get_service_data(dev);
        struct aer_err_source uninitialized_var(e_src);

        if (kfifo_is_empty(&rpc->aer_fifo))
                return IRQ_NONE;

        while (kfifo_get(&rpc->aer_fifo, &e_src))
                aer_isr_one_error(rpc, &e_src);
        return IRQ_HANDLED;
}

/**
 * aer_irq - Root Port's ISR
 * @irq: IRQ assigned to Root Port
 * @context: pointer to Root Port data structure
 *
 * Invoked when Root Port detects AER messages.
 */
static irqreturn_t aer_irq(int irq, void *context)
{
        struct pcie_device *pdev = (struct pcie_device *)context;
        struct aer_rpc *rpc = get_service_data(pdev);
        struct pci_dev *rp = rpc->rpd;
        struct aer_err_source e_src = {};
        int pos = rp->aer_cap;

        pci_read_config_dword(rp, pos + PCI_ERR_ROOT_STATUS, &e_src.status);
        if (!(e_src.status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV)))
                return IRQ_NONE;

        pci_read_config_dword(rp, pos + PCI_ERR_ROOT_ERR_SRC, &e_src.id);
        pci_write_config_dword(rp, pos + PCI_ERR_ROOT_STATUS, e_src.status);

        if (!kfifo_put(&rpc->aer_fifo, e_src))
                return IRQ_HANDLED;

        return IRQ_WAKE_THREAD;
}

static int set_device_error_reporting(struct pci_dev *dev, void *data)
{
        bool enable = *((bool *)data);
        int type = pci_pcie_type(dev);

        if ((type == PCI_EXP_TYPE_ROOT_PORT) ||
            (type == PCI_EXP_TYPE_UPSTREAM) ||
            (type == PCI_EXP_TYPE_DOWNSTREAM)) {
                if (enable)
                        pci_enable_pcie_error_reporting(dev);
                else
                        pci_disable_pcie_error_reporting(dev);
        }

        if (enable)
                pcie_set_ecrc_checking(dev);

        return 0;
}

/**
 * set_downstream_devices_error_reporting - enable/disable the error reporting  bits on the root port and its downstream ports.
 * @dev: pointer to root port's pci_dev data structure
 * @enable: true = enable error reporting, false = disable error reporting.
 */
static void set_downstream_devices_error_reporting(struct pci_dev *dev,
                                                   bool enable)
{
        set_device_error_reporting(dev, &enable);

        if (!dev->subordinate)
                return;
        pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
}

/**
 * aer_enable_rootport - enable Root Port's interrupts when receiving messages
 * @rpc: pointer to a Root Port data structure
 *
 * Invoked when PCIe bus loads AER service driver.
 */
static void aer_enable_rootport(struct aer_rpc *rpc)
{
        struct pci_dev *pdev = rpc->rpd;
        int aer_pos;
        u16 reg16;
        u32 reg32;

        /* Clear PCIe Capability's Device Status */
        pcie_capability_read_word(pdev, PCI_EXP_DEVSTA, &reg16);
        pcie_capability_write_word(pdev, PCI_EXP_DEVSTA, reg16);

        /* Disable system error generation in response to error messages */
        pcie_capability_clear_word(pdev, PCI_EXP_RTCTL,
                                   SYSTEM_ERROR_INTR_ON_MESG_MASK);

        aer_pos = pdev->aer_cap;
        /* Clear error status */
        pci_read_config_dword(pdev, aer_pos + PCI_ERR_ROOT_STATUS, &reg32);
        pci_write_config_dword(pdev, aer_pos + PCI_ERR_ROOT_STATUS, reg32);
        pci_read_config_dword(pdev, aer_pos + PCI_ERR_COR_STATUS, &reg32);
        pci_write_config_dword(pdev, aer_pos + PCI_ERR_COR_STATUS, reg32);
        pci_read_config_dword(pdev, aer_pos + PCI_ERR_UNCOR_STATUS, &reg32);
        pci_write_config_dword(pdev, aer_pos + PCI_ERR_UNCOR_STATUS, reg32);

        /*
         * Enable error reporting for the root port device and downstream port
         * devices.
         */
        set_downstream_devices_error_reporting(pdev, true);

        /* Enable Root Port's interrupt in response to error messages */
        pci_read_config_dword(pdev, aer_pos + PCI_ERR_ROOT_COMMAND, &reg32);
        reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
        pci_write_config_dword(pdev, aer_pos + PCI_ERR_ROOT_COMMAND, reg32);
}

/**
 * aer_disable_rootport - disable Root Port's interrupts when receiving messages
 * @rpc: pointer to a Root Port data structure
 *
 * Invoked when PCIe bus unloads AER service driver.
 */
static void aer_disable_rootport(struct aer_rpc *rpc)
{
        struct pci_dev *pdev = rpc->rpd;
        u32 reg32;
        int pos;

        /*
         * Disable error reporting for the root port device and downstream port
         * devices.
         */
        set_downstream_devices_error_reporting(pdev, false);

        pos = pdev->aer_cap;
        /* Disable Root's interrupt in response to error messages */
        pci_read_config_dword(pdev, pos + PCI_ERR_ROOT_COMMAND, &reg32);
        reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
        pci_write_config_dword(pdev, pos + PCI_ERR_ROOT_COMMAND, reg32);

        /* Clear Root's error status reg */
        pci_read_config_dword(pdev, pos + PCI_ERR_ROOT_STATUS, &reg32);
        pci_write_config_dword(pdev, pos + PCI_ERR_ROOT_STATUS, reg32);
}

/**
 * aer_remove - clean up resources
 * @dev: pointer to the pcie_dev data structure
 *
 * Invoked when PCI Express bus unloads or AER probe fails.
 */
static void aer_remove(struct pcie_device *dev)
{
        struct aer_rpc *rpc = get_service_data(dev);

        aer_disable_rootport(rpc);
}

/**
 * aer_probe - initialize resources
 * @dev: pointer to the pcie_dev data structure
 *
 * Invoked when PCI Express bus loads AER service driver.
 */
static int aer_probe(struct pcie_device *dev)
{
        int status;
        struct aer_rpc *rpc;
        struct device *device = &dev->device;
        struct pci_dev *port = dev->port;

        rpc = devm_kzalloc(device, sizeof(struct aer_rpc), GFP_KERNEL);
        if (!rpc)
                return -ENOMEM;

        rpc->rpd = port;
        INIT_KFIFO(rpc->aer_fifo);
        set_service_data(dev, rpc);

        status = devm_request_threaded_irq(device, dev->irq, aer_irq, aer_isr,
                                           IRQF_SHARED, "aerdrv", dev);
        if (status) {
                pci_err(port, "request AER IRQ %d failed\n", dev->irq);
                return status;
        }

        aer_enable_rootport(rpc);
        pci_info(port, "enabled with IRQ %d\n", dev->irq);
        return 0;
}

/**
 * aer_root_reset - reset link on Root Port
 * @dev: pointer to Root Port's pci_dev data structure
 *
 * Invoked by Port Bus driver when performing link reset at Root Port.
 */
static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
{
        u32 reg32;
        int pos;
        int rc;

        pos = dev->aer_cap;

        /* Disable Root's interrupt in response to error messages */
        pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, &reg32);
        reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
        pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, reg32);

        rc = pci_bus_error_reset(dev);
        pci_info(dev, "Root Port link has been reset\n");

        /* Clear Root Error Status */
        pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
        pci_write_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, reg32);

        /* Enable Root Port's interrupt in response to error messages */
        pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, &reg32);
        reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
        pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, reg32);

        return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
}

static struct pcie_port_service_driver aerdriver = {
        .name           = "aer",
        .port_type      = PCI_EXP_TYPE_ROOT_PORT,
        .service        = PCIE_PORT_SERVICE_AER,

        .probe          = aer_probe,
        .remove         = aer_remove,
};

/**
 * aer_service_init - register AER root service driver
 *
 * Invoked when AER root service driver is loaded.
 */
int __init pcie_aer_init(void)
{
        if (!pci_aer_available() || aer_acpi_firmware_first())
                return -ENXIO;
        return pcie_port_service_register(&aerdriver);
}