GNU Linux-libre 4.19.264-gnu1

[releases.git] / arch / powerpc / kernel / eeh.c

/*
 * Copyright IBM Corporation 2001, 2005, 2006
 * Copyright Dave Engebretsen & Todd Inglett 2001
 * Copyright Linas Vepstas 2005, 2006
 * Copyright 2001-2012 IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 * Please address comments and feedback to Linas Vepstas <linas@austin.ibm.com>
 */

#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/iommu.h>
#include <linux/proc_fs.h>
#include <linux/rbtree.h>
#include <linux/reboot.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/export.h>
#include <linux/of.h>

#include <linux/atomic.h>
#include <asm/debugfs.h>
#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/io.h>
#include <asm/iommu.h>
#include <asm/machdep.h>
#include <asm/ppc-pci.h>
#include <asm/rtas.h>
#include <asm/pte-walk.h>


/** Overview:
 *  EEH, or "Enhanced Error Handling" is a PCI bridge technology for
 *  dealing with PCI bus errors that can't be dealt with within the
 *  usual PCI framework, except by check-stopping the CPU.  Systems
 *  that are designed for high-availability/reliability cannot afford
 *  to crash due to a "mere" PCI error, thus the need for EEH.
 *  An EEH-capable bridge operates by converting a detected error
 *  into a "slot freeze", taking the PCI adapter off-line, making
 *  the slot behave, from the OS'es point of view, as if the slot
 *  were "empty": all reads return 0xff's and all writes are silently
 *  ignored.  EEH slot isolation events can be triggered by parity
 *  errors on the address or data busses (e.g. during posted writes),
 *  which in turn might be caused by low voltage on the bus, dust,
 *  vibration, humidity, radioactivity or plain-old failed hardware.
 *
 *  Note, however, that one of the leading causes of EEH slot
 *  freeze events are buggy device drivers, buggy device microcode,
 *  or buggy device hardware.  This is because any attempt by the
 *  device to bus-master data to a memory address that is not
 *  assigned to the device will trigger a slot freeze.   (The idea
 *  is to prevent devices-gone-wild from corrupting system memory).
 *  Buggy hardware/drivers will have a miserable time co-existing
 *  with EEH.
 *
 *  Ideally, a PCI device driver, when suspecting that an isolation
 *  event has occurred (e.g. by reading 0xff's), will then ask EEH
 *  whether this is the case, and then take appropriate steps to
 *  reset the PCI slot, the PCI device, and then resume operations.
 *  However, until that day,  the checking is done here, with the
 *  eeh_check_failure() routine embedded in the MMIO macros.  If
 *  the slot is found to be isolated, an "EEH Event" is synthesized
 *  and sent out for processing.
 */

/* If a device driver keeps reading an MMIO register in an interrupt
 * handler after a slot isolation event, it might be broken.
 * This sets the threshold for how many read attempts we allow
 * before printing an error message.
 */
#define EEH_MAX_FAILS   2100000

/* Time to wait for a PCI slot to report status, in milliseconds */
#define PCI_BUS_RESET_WAIT_MSEC (5*60*1000)

/*
 * EEH probe mode support, which is part of the flags,
 * is to support multiple platforms for EEH. Some platforms
 * like pSeries do PCI emunation based on device tree.
 * However, other platforms like powernv probe PCI devices
 * from hardware. The flag is used to distinguish that.
 * In addition, struct eeh_ops::probe would be invoked for
 * particular OF node or PCI device so that the corresponding
 * PE would be created there.
 */
int eeh_subsystem_flags;
EXPORT_SYMBOL(eeh_subsystem_flags);

/*
 * EEH allowed maximal frozen times. If one particular PE's
 * frozen count in last hour exceeds this limit, the PE will
 * be forced to be offline permanently.
 */
int eeh_max_freezes = 5;

/* Platform dependent EEH operations */
struct eeh_ops *eeh_ops = NULL;

/* Lock to avoid races due to multiple reports of an error */
DEFINE_RAW_SPINLOCK(confirm_error_lock);
EXPORT_SYMBOL_GPL(confirm_error_lock);

/* Lock to protect passed flags */
static DEFINE_MUTEX(eeh_dev_mutex);

/* Buffer for reporting pci register dumps. Its here in BSS, and
 * not dynamically alloced, so that it ends up in RMO where RTAS
 * can access it.
 */
#define EEH_PCI_REGS_LOG_LEN 8192
static unsigned char pci_regs_buf[EEH_PCI_REGS_LOG_LEN];

/*
 * The struct is used to maintain the EEH global statistic
 * information. Besides, the EEH global statistics will be
 * exported to user space through procfs
 */
struct eeh_stats {
        u64 no_device;          /* PCI device not found         */
        u64 no_dn;              /* OF node not found            */
        u64 no_cfg_addr;        /* Config address not found     */
        u64 ignored_check;      /* EEH check skipped            */
        u64 total_mmio_ffs;     /* Total EEH checks             */
        u64 false_positives;    /* Unnecessary EEH checks       */
        u64 slot_resets;        /* PE reset                     */
};

static struct eeh_stats eeh_stats;

static int __init eeh_setup(char *str)
{
        if (!strcmp(str, "off"))
                eeh_add_flag(EEH_FORCE_DISABLED);
        else if (!strcmp(str, "early_log"))
                eeh_add_flag(EEH_EARLY_DUMP_LOG);

        return 1;
}
__setup("eeh=", eeh_setup);

/*
 * This routine captures assorted PCI configuration space data
 * for the indicated PCI device, and puts them into a buffer
 * for RTAS error logging.
 */
static size_t eeh_dump_dev_log(struct eeh_dev *edev, char *buf, size_t len)
{
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);
        u32 cfg;
        int cap, i;
        int n = 0, l = 0;
        char buffer[128];

        if (!pdn) {
                pr_warn("EEH: Note: No error log for absent device.\n");
                return 0;
        }

        n += scnprintf(buf+n, len-n, "%04x:%02x:%02x.%01x\n",
                       pdn->phb->global_number, pdn->busno,
                       PCI_SLOT(pdn->devfn), PCI_FUNC(pdn->devfn));
        pr_warn("EEH: of node=%04x:%02x:%02x.%01x\n",
                pdn->phb->global_number, pdn->busno,
                PCI_SLOT(pdn->devfn), PCI_FUNC(pdn->devfn));

        eeh_ops->read_config(pdn, PCI_VENDOR_ID, 4, &cfg);
        n += scnprintf(buf+n, len-n, "dev/vend:%08x\n", cfg);
        pr_warn("EEH: PCI device/vendor: %08x\n", cfg);

        eeh_ops->read_config(pdn, PCI_COMMAND, 4, &cfg);
        n += scnprintf(buf+n, len-n, "cmd/stat:%x\n", cfg);
        pr_warn("EEH: PCI cmd/status register: %08x\n", cfg);

        /* Gather bridge-specific registers */
        if (edev->mode & EEH_DEV_BRIDGE) {
                eeh_ops->read_config(pdn, PCI_SEC_STATUS, 2, &cfg);
                n += scnprintf(buf+n, len-n, "sec stat:%x\n", cfg);
                pr_warn("EEH: Bridge secondary status: %04x\n", cfg);

                eeh_ops->read_config(pdn, PCI_BRIDGE_CONTROL, 2, &cfg);
                n += scnprintf(buf+n, len-n, "brdg ctl:%x\n", cfg);
                pr_warn("EEH: Bridge control: %04x\n", cfg);
        }

        /* Dump out the PCI-X command and status regs */
        cap = edev->pcix_cap;
        if (cap) {
                eeh_ops->read_config(pdn, cap, 4, &cfg);
                n += scnprintf(buf+n, len-n, "pcix-cmd:%x\n", cfg);
                pr_warn("EEH: PCI-X cmd: %08x\n", cfg);

                eeh_ops->read_config(pdn, cap+4, 4, &cfg);
                n += scnprintf(buf+n, len-n, "pcix-stat:%x\n", cfg);
                pr_warn("EEH: PCI-X status: %08x\n", cfg);
        }

        /* If PCI-E capable, dump PCI-E cap 10 */
        cap = edev->pcie_cap;
        if (cap) {
                n += scnprintf(buf+n, len-n, "pci-e cap10:\n");
                pr_warn("EEH: PCI-E capabilities and status follow:\n");

                for (i=0; i<=8; i++) {
                        eeh_ops->read_config(pdn, cap+4*i, 4, &cfg);
                        n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);

                        if ((i % 4) == 0) {
                                if (i != 0)
                                        pr_warn("%s\n", buffer);

                                l = scnprintf(buffer, sizeof(buffer),
                                              "EEH: PCI-E %02x: %08x ",
                                              4*i, cfg);
                        } else {
                                l += scnprintf(buffer+l, sizeof(buffer)-l,
                                               "%08x ", cfg);
                        }

                }

                pr_warn("%s\n", buffer);
        }

        /* If AER capable, dump it */
        cap = edev->aer_cap;
        if (cap) {
                n += scnprintf(buf+n, len-n, "pci-e AER:\n");
                pr_warn("EEH: PCI-E AER capability register set follows:\n");

                for (i=0; i<=13; i++) {
                        eeh_ops->read_config(pdn, cap+4*i, 4, &cfg);
                        n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);

                        if ((i % 4) == 0) {
                                if (i != 0)
                                        pr_warn("%s\n", buffer);

                                l = scnprintf(buffer, sizeof(buffer),
                                              "EEH: PCI-E AER %02x: %08x ",
                                              4*i, cfg);
                        } else {
                                l += scnprintf(buffer+l, sizeof(buffer)-l,
                                               "%08x ", cfg);
                        }
                }

                pr_warn("%s\n", buffer);
        }

        return n;
}

static void *eeh_dump_pe_log(struct eeh_pe *pe, void *flag)
{
        struct eeh_dev *edev, *tmp;
        size_t *plen = flag;

        eeh_pe_for_each_dev(pe, edev, tmp)
                *plen += eeh_dump_dev_log(edev, pci_regs_buf + *plen,
                                          EEH_PCI_REGS_LOG_LEN - *plen);

        return NULL;
}

/**
 * eeh_slot_error_detail - Generate combined log including driver log and error log
 * @pe: EEH PE
 * @severity: temporary or permanent error log
 *
 * This routine should be called to generate the combined log, which
 * is comprised of driver log and error log. The driver log is figured
 * out from the config space of the corresponding PCI device, while
 * the error log is fetched through platform dependent function call.
 */
void eeh_slot_error_detail(struct eeh_pe *pe, int severity)
{
        size_t loglen = 0;

        /*
         * When the PHB is fenced or dead, it's pointless to collect
         * the data from PCI config space because it should return
         * 0xFF's. For ER, we still retrieve the data from the PCI
         * config space.
         *
         * For pHyp, we have to enable IO for log retrieval. Otherwise,
         * 0xFF's is always returned from PCI config space.
         *
         * When the @severity is EEH_LOG_PERM, the PE is going to be
         * removed. Prior to that, the drivers for devices included in
         * the PE will be closed. The drivers rely on working IO path
         * to bring the devices to quiet state. Otherwise, PCI traffic
         * from those devices after they are removed is like to cause
         * another unexpected EEH error.
         */
        if (!(pe->type & EEH_PE_PHB)) {
                if (eeh_has_flag(EEH_ENABLE_IO_FOR_LOG) ||
                    severity == EEH_LOG_PERM)
                        eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);

                /*
                 * The config space of some PCI devices can't be accessed
                 * when their PEs are in frozen state. Otherwise, fenced
                 * PHB might be seen. Those PEs are identified with flag
                 * EEH_PE_CFG_RESTRICTED, indicating EEH_PE_CFG_BLOCKED
                 * is set automatically when the PE is put to EEH_PE_ISOLATED.
                 *
                 * Restoring BARs possibly triggers PCI config access in
                 * (OPAL) firmware and then causes fenced PHB. If the
                 * PCI config is blocked with flag EEH_PE_CFG_BLOCKED, it's
                 * pointless to restore BARs and dump config space.
                 */
                eeh_ops->configure_bridge(pe);
                if (!(pe->state & EEH_PE_CFG_BLOCKED)) {
                        eeh_pe_restore_bars(pe);

                        pci_regs_buf[0] = 0;
                        eeh_pe_traverse(pe, eeh_dump_pe_log, &loglen);
                }
        }

        eeh_ops->get_log(pe, severity, pci_regs_buf, loglen);
}

/**
 * eeh_token_to_phys - Convert EEH address token to phys address
 * @token: I/O token, should be address in the form 0xA....
 *
 * This routine should be called to convert virtual I/O address
 * to physical one.
 */
static inline unsigned long eeh_token_to_phys(unsigned long token)
{
        pte_t *ptep;
        unsigned long pa;
        int hugepage_shift;

        /*
         * We won't find hugepages here(this is iomem). Hence we are not
         * worried about _PAGE_SPLITTING/collapse. Also we will not hit
         * page table free, because of init_mm.
         */
        ptep = find_init_mm_pte(token, &hugepage_shift);
        if (!ptep)
                return token;

        pa = pte_pfn(*ptep);

        /* On radix we can do hugepage mappings for io, so handle that */
        if (!hugepage_shift)
                hugepage_shift = PAGE_SHIFT;

        pa <<= PAGE_SHIFT;
        pa |= token & ((1ul << hugepage_shift) - 1);
        return pa;
}

/*
 * On PowerNV platform, we might already have fenced PHB there.
 * For that case, it's meaningless to recover frozen PE. Intead,
 * We have to handle fenced PHB firstly.
 */
static int eeh_phb_check_failure(struct eeh_pe *pe)
{
        struct eeh_pe *phb_pe;
        unsigned long flags;
        int ret;

        if (!eeh_has_flag(EEH_PROBE_MODE_DEV))
                return -EPERM;

        /* Find the PHB PE */
        phb_pe = eeh_phb_pe_get(pe->phb);
        if (!phb_pe) {
                pr_warn("%s Can't find PE for PHB#%x\n",
                        __func__, pe->phb->global_number);
                return -EEXIST;
        }

        /* If the PHB has been in problematic state */
        eeh_serialize_lock(&flags);
        if (phb_pe->state & EEH_PE_ISOLATED) {
                ret = 0;
                goto out;
        }

        /* Check PHB state */
        ret = eeh_ops->get_state(phb_pe, NULL);
        if ((ret < 0) ||
            (ret == EEH_STATE_NOT_SUPPORT) || eeh_state_active(ret)) {
                ret = 0;
                goto out;
        }

        /* Isolate the PHB and send event */
        eeh_pe_state_mark(phb_pe, EEH_PE_ISOLATED);
        eeh_serialize_unlock(flags);

        pr_err("EEH: PHB#%x failure detected, location: %s\n",
                phb_pe->phb->global_number, eeh_pe_loc_get(phb_pe));
        dump_stack();
        eeh_send_failure_event(phb_pe);

        return 1;
out:
        eeh_serialize_unlock(flags);
        return ret;
}

/**
 * eeh_dev_check_failure - Check if all 1's data is due to EEH slot freeze
 * @edev: eeh device
 *
 * Check for an EEH failure for the given device node.  Call this
 * routine if the result of a read was all 0xff's and you want to
 * find out if this is due to an EEH slot freeze.  This routine
 * will query firmware for the EEH status.
 *
 * Returns 0 if there has not been an EEH error; otherwise returns
 * a non-zero value and queues up a slot isolation event notification.
 *
 * It is safe to call this routine in an interrupt context.
 */
int eeh_dev_check_failure(struct eeh_dev *edev)
{
        int ret;
        unsigned long flags;
        struct device_node *dn;
        struct pci_dev *dev;
        struct eeh_pe *pe, *parent_pe, *phb_pe;
        int rc = 0;
        const char *location = NULL;

        eeh_stats.total_mmio_ffs++;

        if (!eeh_enabled())
                return 0;

        if (!edev) {
                eeh_stats.no_dn++;
                return 0;
        }
        dev = eeh_dev_to_pci_dev(edev);
        pe = eeh_dev_to_pe(edev);

        /* Access to IO BARs might get this far and still not want checking. */
        if (!pe) {
                eeh_stats.ignored_check++;
                pr_debug("EEH: Ignored check for %s\n",
                        eeh_pci_name(dev));
                return 0;
        }

        if (!pe->addr && !pe->config_addr) {
                eeh_stats.no_cfg_addr++;
                return 0;
        }

        /*
         * On PowerNV platform, we might already have fenced PHB
         * there and we need take care of that firstly.
         */
        ret = eeh_phb_check_failure(pe);
        if (ret > 0)
                return ret;

        /*
         * If the PE isn't owned by us, we shouldn't check the
         * state. Instead, let the owner handle it if the PE has
         * been frozen.
         */
        if (eeh_pe_passed(pe))
                return 0;

        /* If we already have a pending isolation event for this
         * slot, we know it's bad already, we don't need to check.
         * Do this checking under a lock; as multiple PCI devices
         * in one slot might report errors simultaneously, and we
         * only want one error recovery routine running.
         */
        eeh_serialize_lock(&flags);
        rc = 1;
        if (pe->state & EEH_PE_ISOLATED) {
                pe->check_count++;
                if (pe->check_count == EEH_MAX_FAILS) {
                        dn = pci_device_to_OF_node(dev);
                        if (dn)
                                location = of_get_property(dn, "ibm,loc-code",
                                                NULL);
                        printk(KERN_ERR "EEH: %d reads ignored for recovering device at "
                                "location=%s driver=%s pci addr=%s\n",
                                pe->check_count,
                                location ? location : "unknown",
                                eeh_driver_name(dev), eeh_pci_name(dev));
                        printk(KERN_ERR "EEH: Might be infinite loop in %s driver\n",
                                eeh_driver_name(dev));
                        dump_stack();
                }
                goto dn_unlock;
        }

        /*
         * Now test for an EEH failure.  This is VERY expensive.
         * Note that the eeh_config_addr may be a parent device
         * in the case of a device behind a bridge, or it may be
         * function zero of a multi-function device.
         * In any case they must share a common PHB.
         */
        ret = eeh_ops->get_state(pe, NULL);

        /* Note that config-io to empty slots may fail;
         * they are empty when they don't have children.
         * We will punt with the following conditions: Failure to get
         * PE's state, EEH not support and Permanently unavailable
         * state, PE is in good state.
         */
        if ((ret < 0) ||
            (ret == EEH_STATE_NOT_SUPPORT) || eeh_state_active(ret)) {
                eeh_stats.false_positives++;
                pe->false_positives++;
                rc = 0;
                goto dn_unlock;
        }

        /*
         * It should be corner case that the parent PE has been
         * put into frozen state as well. We should take care
         * that at first.
         */
        parent_pe = pe->parent;
        while (parent_pe) {
                /* Hit the ceiling ? */
                if (parent_pe->type & EEH_PE_PHB)
                        break;

                /* Frozen parent PE ? */
                ret = eeh_ops->get_state(parent_pe, NULL);
                if (ret > 0 && !eeh_state_active(ret)) {
                        pe = parent_pe;
                        pr_err("EEH: Failure of PHB#%x-PE#%x will be handled at parent PHB#%x-PE#%x.\n",
                               pe->phb->global_number, pe->addr,
                               pe->phb->global_number, parent_pe->addr);
                }

                /* Next parent level */
                parent_pe = parent_pe->parent;
        }

        eeh_stats.slot_resets++;

        /* Avoid repeated reports of this failure, including problems
         * with other functions on this device, and functions under
         * bridges.
         */
        eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
        eeh_serialize_unlock(flags);

        /* Most EEH events are due to device driver bugs.  Having
         * a stack trace will help the device-driver authors figure
         * out what happened.  So print that out.
         */
        phb_pe = eeh_phb_pe_get(pe->phb);
        pr_err("EEH: Frozen PHB#%x-PE#%x detected\n",
               pe->phb->global_number, pe->addr);
        pr_err("EEH: PE location: %s, PHB location: %s\n",
               eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe));
        dump_stack();

        eeh_send_failure_event(pe);

        return 1;

dn_unlock:
        eeh_serialize_unlock(flags);
        return rc;
}

EXPORT_SYMBOL_GPL(eeh_dev_check_failure);

/**
 * eeh_check_failure - Check if all 1's data is due to EEH slot freeze
 * @token: I/O address
 *
 * Check for an EEH failure at the given I/O address. Call this
 * routine if the result of a read was all 0xff's and you want to
 * find out if this is due to an EEH slot freeze event. This routine
 * will query firmware for the EEH status.
 *
 * Note this routine is safe to call in an interrupt context.
 */
int eeh_check_failure(const volatile void __iomem *token)
{
        unsigned long addr;
        struct eeh_dev *edev;

        /* Finding the phys addr + pci device; this is pretty quick. */
        addr = eeh_token_to_phys((unsigned long __force) token);
        edev = eeh_addr_cache_get_dev(addr);
        if (!edev) {
                eeh_stats.no_device++;
                return 0;
        }

        return eeh_dev_check_failure(edev);
}
EXPORT_SYMBOL(eeh_check_failure);


/**
 * eeh_pci_enable - Enable MMIO or DMA transfers for this slot
 * @pe: EEH PE
 *
 * This routine should be called to reenable frozen MMIO or DMA
 * so that it would work correctly again. It's useful while doing
 * recovery or log collection on the indicated device.
 */
int eeh_pci_enable(struct eeh_pe *pe, int function)
{
        int active_flag, rc;

        /*
         * pHyp doesn't allow to enable IO or DMA on unfrozen PE.
         * Also, it's pointless to enable them on unfrozen PE. So
         * we have to check before enabling IO or DMA.
         */
        switch (function) {
        case EEH_OPT_THAW_MMIO:
                active_flag = EEH_STATE_MMIO_ACTIVE | EEH_STATE_MMIO_ENABLED;
                break;
        case EEH_OPT_THAW_DMA:
                active_flag = EEH_STATE_DMA_ACTIVE;
                break;
        case EEH_OPT_DISABLE:
        case EEH_OPT_ENABLE:
        case EEH_OPT_FREEZE_PE:
                active_flag = 0;
                break;
        default:
                pr_warn("%s: Invalid function %d\n",
                        __func__, function);
                return -EINVAL;
        }

        /*
         * Check if IO or DMA has been enabled before
         * enabling them.
         */
        if (active_flag) {
                rc = eeh_ops->get_state(pe, NULL);
                if (rc < 0)
                        return rc;

                /* Needn't enable it at all */
                if (rc == EEH_STATE_NOT_SUPPORT)
                        return 0;

                /* It's already enabled */
                if (rc & active_flag)
                        return 0;
        }


        /* Issue the request */
        rc = eeh_ops->set_option(pe, function);
        if (rc)
                pr_warn("%s: Unexpected state change %d on "
                        "PHB#%x-PE#%x, err=%d\n",
                        __func__, function, pe->phb->global_number,
                        pe->addr, rc);

        /* Check if the request is finished successfully */
        if (active_flag) {
                rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
                if (rc < 0)
                        return rc;

                if (rc & active_flag)
                        return 0;

                return -EIO;
        }

        return rc;
}

static void *eeh_disable_and_save_dev_state(struct eeh_dev *edev,
                                            void *userdata)
{
        struct pci_dev *pdev = eeh_dev_to_pci_dev(edev);
        struct pci_dev *dev = userdata;

        /*
         * The caller should have disabled and saved the
         * state for the specified device
         */
        if (!pdev || pdev == dev)
                return NULL;

        /* Ensure we have D0 power state */
        pci_set_power_state(pdev, PCI_D0);

        /* Save device state */
        pci_save_state(pdev);

        /*
         * Disable device to avoid any DMA traffic and
         * interrupt from the device
         */
        pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);

        return NULL;
}

static void *eeh_restore_dev_state(struct eeh_dev *edev, void *userdata)
{
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);
        struct pci_dev *pdev = eeh_dev_to_pci_dev(edev);
        struct pci_dev *dev = userdata;

        if (!pdev)
                return NULL;

        /* Apply customization from firmware */
        if (pdn && eeh_ops->restore_config)
                eeh_ops->restore_config(pdn);

        /* The caller should restore state for the specified device */
        if (pdev != dev)
                pci_restore_state(pdev);

        return NULL;
}

int eeh_restore_vf_config(struct pci_dn *pdn)
{
        struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
        u32 devctl, cmd, cap2, aer_capctl;
        int old_mps;

        if (edev->pcie_cap) {
                /* Restore MPS */
                old_mps = (ffs(pdn->mps) - 8) << 5;
                eeh_ops->read_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
                                     2, &devctl);
                devctl &= ~PCI_EXP_DEVCTL_PAYLOAD;
                devctl |= old_mps;
                eeh_ops->write_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
                                      2, devctl);

                /* Disable Completion Timeout if possible */
                eeh_ops->read_config(pdn, edev->pcie_cap + PCI_EXP_DEVCAP2,
                                     4, &cap2);
                if (cap2 & PCI_EXP_DEVCAP2_COMP_TMOUT_DIS) {
                        eeh_ops->read_config(pdn,
                                             edev->pcie_cap + PCI_EXP_DEVCTL2,
                                             4, &cap2);
                        cap2 |= PCI_EXP_DEVCTL2_COMP_TMOUT_DIS;
                        eeh_ops->write_config(pdn,
                                              edev->pcie_cap + PCI_EXP_DEVCTL2,
                                              4, cap2);
                }
        }

        /* Enable SERR and parity checking */
        eeh_ops->read_config(pdn, PCI_COMMAND, 2, &cmd);
        cmd |= (PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
        eeh_ops->write_config(pdn, PCI_COMMAND, 2, cmd);

        /* Enable report various errors */
        if (edev->pcie_cap) {
                eeh_ops->read_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
                                     2, &devctl);
                devctl &= ~PCI_EXP_DEVCTL_CERE;
                devctl |= (PCI_EXP_DEVCTL_NFERE |
                           PCI_EXP_DEVCTL_FERE |
                           PCI_EXP_DEVCTL_URRE);
                eeh_ops->write_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
                                      2, devctl);
        }

        /* Enable ECRC generation and check */
        if (edev->pcie_cap && edev->aer_cap) {
                eeh_ops->read_config(pdn, edev->aer_cap + PCI_ERR_CAP,
                                     4, &aer_capctl);
                aer_capctl |= (PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE);
                eeh_ops->write_config(pdn, edev->aer_cap + PCI_ERR_CAP,
                                      4, aer_capctl);
        }

        return 0;
}

/**
 * pcibios_set_pcie_reset_state - Set PCI-E reset state
 * @dev: pci device struct
 * @state: reset state to enter
 *
 * Return value:
 *      0 if success
 */
int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
{
        struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
        struct eeh_pe *pe = eeh_dev_to_pe(edev);

        if (!pe) {
                pr_err("%s: No PE found on PCI device %s\n",
                        __func__, pci_name(dev));
                return -EINVAL;
        }

        switch (state) {
        case pcie_deassert_reset:
                eeh_ops->reset(pe, EEH_RESET_DEACTIVATE);
                eeh_unfreeze_pe(pe, false);
                if (!(pe->type & EEH_PE_VF))
                        eeh_pe_state_clear(pe, EEH_PE_CFG_BLOCKED);
                eeh_pe_dev_traverse(pe, eeh_restore_dev_state, dev);
                eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
                break;
        case pcie_hot_reset:
                eeh_pe_state_mark_with_cfg(pe, EEH_PE_ISOLATED);
                eeh_ops->set_option(pe, EEH_OPT_FREEZE_PE);
                eeh_pe_dev_traverse(pe, eeh_disable_and_save_dev_state, dev);
                if (!(pe->type & EEH_PE_VF))
                        eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
                eeh_ops->reset(pe, EEH_RESET_HOT);
                break;
        case pcie_warm_reset:
                eeh_pe_state_mark_with_cfg(pe, EEH_PE_ISOLATED);
                eeh_ops->set_option(pe, EEH_OPT_FREEZE_PE);
                eeh_pe_dev_traverse(pe, eeh_disable_and_save_dev_state, dev);
                if (!(pe->type & EEH_PE_VF))
                        eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
                eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
                break;
        default:
                eeh_pe_state_clear(pe, EEH_PE_ISOLATED | EEH_PE_CFG_BLOCKED);
                return -EINVAL;
        };

        return 0;
}

/**
 * eeh_set_pe_freset - Check the required reset for the indicated device
 * @data: EEH device
 * @flag: return value
 *
 * Each device might have its preferred reset type: fundamental or
 * hot reset. The routine is used to collected the information for
 * the indicated device and its children so that the bunch of the
 * devices could be reset properly.
 */
static void *eeh_set_dev_freset(struct eeh_dev *edev, void *flag)
{
        struct pci_dev *dev;
        unsigned int *freset = (unsigned int *)flag;

        dev = eeh_dev_to_pci_dev(edev);
        if (dev)
                *freset |= dev->needs_freset;

        return NULL;
}

/**
 * eeh_pe_reset_full - Complete a full reset process on the indicated PE
 * @pe: EEH PE
 *
 * This function executes a full reset procedure on a PE, including setting
 * the appropriate flags, performing a fundamental or hot reset, and then
 * deactivating the reset status.  It is designed to be used within the EEH
 * subsystem, as opposed to eeh_pe_reset which is exported to drivers and
 * only performs a single operation at a time.
 *
 * This function will attempt to reset a PE three times before failing.
 */
int eeh_pe_reset_full(struct eeh_pe *pe)
{
        int reset_state = (EEH_PE_RESET | EEH_PE_CFG_BLOCKED);
        int type = EEH_RESET_HOT;
        unsigned int freset = 0;
        int i, state, ret;

        /*
         * Determine the type of reset to perform - hot or fundamental.
         * Hot reset is the default operation, unless any device under the
         * PE requires a fundamental reset.
         */
        eeh_pe_dev_traverse(pe, eeh_set_dev_freset, &freset);

        if (freset)
                type = EEH_RESET_FUNDAMENTAL;

        /* Mark the PE as in reset state and block config space accesses */
        eeh_pe_state_mark(pe, reset_state);

        /* Make three attempts at resetting the bus */
        for (i = 0; i < 3; i++) {
                ret = eeh_pe_reset(pe, type);
                if (ret)
                        break;

                ret = eeh_pe_reset(pe, EEH_RESET_DEACTIVATE);
                if (ret)
                        break;

                /* Wait until the PE is in a functioning state */
                state = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
                if (eeh_state_active(state))
                        break;

                if (state < 0) {
                        pr_warn("%s: Unrecoverable slot failure on PHB#%x-PE#%x",
                                __func__, pe->phb->global_number, pe->addr);
                        ret = -ENOTRECOVERABLE;
                        break;
                }

                /* Set error in case this is our last attempt */
                ret = -EIO;
                pr_warn("%s: Failure %d resetting PHB#%x-PE#%x\n (%d)\n",
                        __func__, state, pe->phb->global_number, pe->addr, (i + 1));
        }

        eeh_pe_state_clear(pe, reset_state);
        return ret;
}

/**
 * eeh_save_bars - Save device bars
 * @edev: PCI device associated EEH device
 *
 * Save the values of the device bars. Unlike the restore
 * routine, this routine is *not* recursive. This is because
 * PCI devices are added individually; but, for the restore,
 * an entire slot is reset at a time.
 */
void eeh_save_bars(struct eeh_dev *edev)
{
        struct pci_dn *pdn;
        int i;

        pdn = eeh_dev_to_pdn(edev);
        if (!pdn)
                return;

        for (i = 0; i < 16; i++)
                eeh_ops->read_config(pdn, i * 4, 4, &edev->config_space[i]);

        /*
         * For PCI bridges including root port, we need enable bus
         * master explicitly. Otherwise, it can't fetch IODA table
         * entries correctly. So we cache the bit in advance so that
         * we can restore it after reset, either PHB range or PE range.
         */
        if (edev->mode & EEH_DEV_BRIDGE)
                edev->config_space[1] |= PCI_COMMAND_MASTER;
}

/**
 * eeh_ops_register - Register platform dependent EEH operations
 * @ops: platform dependent EEH operations
 *
 * Register the platform dependent EEH operation callback
 * functions. The platform should call this function before
 * any other EEH operations.
 */
int __init eeh_ops_register(struct eeh_ops *ops)
{
        if (!ops->name) {
                pr_warn("%s: Invalid EEH ops name for %p\n",
                        __func__, ops);
                return -EINVAL;
        }

        if (eeh_ops && eeh_ops != ops) {
                pr_warn("%s: EEH ops of platform %s already existing (%s)\n",
                        __func__, eeh_ops->name, ops->name);
                return -EEXIST;
        }

        eeh_ops = ops;

        return 0;
}

/**
 * eeh_ops_unregister - Unreigster platform dependent EEH operations
 * @name: name of EEH platform operations
 *
 * Unregister the platform dependent EEH operation callback
 * functions.
 */
int __exit eeh_ops_unregister(const char *name)
{
        if (!name || !strlen(name)) {
                pr_warn("%s: Invalid EEH ops name\n",
                        __func__);
                return -EINVAL;
        }

        if (eeh_ops && !strcmp(eeh_ops->name, name)) {
                eeh_ops = NULL;
                return 0;
        }

        return -EEXIST;
}

static int eeh_reboot_notifier(struct notifier_block *nb,
                               unsigned long action, void *unused)
{
        eeh_clear_flag(EEH_ENABLED);
        return NOTIFY_DONE;
}

static struct notifier_block eeh_reboot_nb = {
        .notifier_call = eeh_reboot_notifier,
};

void eeh_probe_devices(void)
{
        struct pci_controller *hose, *tmp;
        struct pci_dn *pdn;

        /* Enable EEH for all adapters */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                pdn = hose->pci_data;
                traverse_pci_dn(pdn, eeh_ops->probe, NULL);
        }
}

/**
 * eeh_init - EEH initialization
 *
 * Initialize EEH by trying to enable it for all of the adapters in the system.
 * As a side effect we can determine here if eeh is supported at all.
 * Note that we leave EEH on so failed config cycles won't cause a machine
 * check.  If a user turns off EEH for a particular adapter they are really
 * telling Linux to ignore errors.  Some hardware (e.g. POWER5) won't
 * grant access to a slot if EEH isn't enabled, and so we always enable
 * EEH for all slots/all devices.
 *
 * The eeh-force-off option disables EEH checking globally, for all slots.
 * Even if force-off is set, the EEH hardware is still enabled, so that
 * newer systems can boot.
 */
static int eeh_init(void)
{
        struct pci_controller *hose, *tmp;
        int ret = 0;

        /* Register reboot notifier */
        ret = register_reboot_notifier(&eeh_reboot_nb);
        if (ret) {
                pr_warn("%s: Failed to register notifier (%d)\n",
                        __func__, ret);
                return ret;
        }

        /* call platform initialization function */
        if (!eeh_ops) {
                pr_warn("%s: Platform EEH operation not found\n",
                        __func__);
                return -EEXIST;
        } else if ((ret = eeh_ops->init()))
                return ret;

        /* Initialize PHB PEs */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
                eeh_dev_phb_init_dynamic(hose);

        /* Initialize EEH event */
        ret = eeh_event_init();
        if (ret)
                return ret;

        eeh_probe_devices();

        if (eeh_enabled())
                pr_info("EEH: PCI Enhanced I/O Error Handling Enabled\n");
        else if (!eeh_has_flag(EEH_POSTPONED_PROBE))
                pr_info("EEH: No capable adapters found\n");

        return ret;
}

core_initcall_sync(eeh_init);

/**
 * eeh_add_device_early - Enable EEH for the indicated device node
 * @pdn: PCI device node for which to set up EEH
 *
 * This routine must be used to perform EEH initialization for PCI
 * devices that were added after system boot (e.g. hotplug, dlpar).
 * This routine must be called before any i/o is performed to the
 * adapter (inluding any config-space i/o).
 * Whether this actually enables EEH or not for this device depends
 * on the CEC architecture, type of the device, on earlier boot
 * command-line arguments & etc.
 */
void eeh_add_device_early(struct pci_dn *pdn)
{
        struct pci_controller *phb = pdn ? pdn->phb : NULL;
        struct eeh_dev *edev = pdn_to_eeh_dev(pdn);

        if (!edev)
                return;

        if (!eeh_has_flag(EEH_PROBE_MODE_DEVTREE))
                return;

        /* USB Bus children of PCI devices will not have BUID's */
        if (NULL == phb ||
            (eeh_has_flag(EEH_PROBE_MODE_DEVTREE) && 0 == phb->buid))
                return;

        eeh_ops->probe(pdn, NULL);
}

/**
 * eeh_add_device_tree_early - Enable EEH for the indicated device
 * @pdn: PCI device node
 *
 * This routine must be used to perform EEH initialization for the
 * indicated PCI device that was added after system boot (e.g.
 * hotplug, dlpar).
 */
void eeh_add_device_tree_early(struct pci_dn *pdn)
{
        struct pci_dn *n;

        if (!pdn)
                return;

        list_for_each_entry(n, &pdn->child_list, list)
                eeh_add_device_tree_early(n);
        eeh_add_device_early(pdn);
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_early);

/**
 * eeh_add_device_late - Perform EEH initialization for the indicated pci device
 * @dev: pci device for which to set up EEH
 *
 * This routine must be used to complete EEH initialization for PCI
 * devices that were added after system boot (e.g. hotplug, dlpar).
 */
void eeh_add_device_late(struct pci_dev *dev)
{
        struct pci_dn *pdn;
        struct eeh_dev *edev;

        if (!dev || !eeh_enabled())
                return;

        pr_debug("EEH: Adding device %s\n", pci_name(dev));

        pdn = pci_get_pdn_by_devfn(dev->bus, dev->devfn);
        edev = pdn_to_eeh_dev(pdn);
        if (edev->pdev == dev) {
                pr_debug("EEH: Already referenced !\n");
                return;
        }

        /*
         * The EEH cache might not be removed correctly because of
         * unbalanced kref to the device during unplug time, which
         * relies on pcibios_release_device(). So we have to remove
         * that here explicitly.
         */
        if (edev->pdev) {
                eeh_rmv_from_parent_pe(edev);
                eeh_addr_cache_rmv_dev(edev->pdev);
                eeh_sysfs_remove_device(edev->pdev);
                edev->mode &= ~EEH_DEV_SYSFS;

                /*
                 * We definitely should have the PCI device removed
                 * though it wasn't correctly. So we needn't call
                 * into error handler afterwards.
                 */
                edev->mode |= EEH_DEV_NO_HANDLER;

                edev->pdev = NULL;
                dev->dev.archdata.edev = NULL;
        }

        if (eeh_has_flag(EEH_PROBE_MODE_DEV))
                eeh_ops->probe(pdn, NULL);

        edev->pdev = dev;
        dev->dev.archdata.edev = edev;

        eeh_addr_cache_insert_dev(dev);
}

/**
 * eeh_add_device_tree_late - Perform EEH initialization for the indicated PCI bus
 * @bus: PCI bus
 *
 * This routine must be used to perform EEH initialization for PCI
 * devices which are attached to the indicated PCI bus. The PCI bus
 * is added after system boot through hotplug or dlpar.
 */
void eeh_add_device_tree_late(struct pci_bus *bus)
{
        struct pci_dev *dev;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                eeh_add_device_late(dev);
                if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
                        struct pci_bus *subbus = dev->subordinate;
                        if (subbus)
                                eeh_add_device_tree_late(subbus);
                }
        }
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);

/**
 * eeh_add_sysfs_files - Add EEH sysfs files for the indicated PCI bus
 * @bus: PCI bus
 *
 * This routine must be used to add EEH sysfs files for PCI
 * devices which are attached to the indicated PCI bus. The PCI bus
 * is added after system boot through hotplug or dlpar.
 */
void eeh_add_sysfs_files(struct pci_bus *bus)
{
        struct pci_dev *dev;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                eeh_sysfs_add_device(dev);
                if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
                        struct pci_bus *subbus = dev->subordinate;
                        if (subbus)
                                eeh_add_sysfs_files(subbus);
                }
        }
}
EXPORT_SYMBOL_GPL(eeh_add_sysfs_files);

/**
 * eeh_remove_device - Undo EEH setup for the indicated pci device
 * @dev: pci device to be removed
 *
 * This routine should be called when a device is removed from
 * a running system (e.g. by hotplug or dlpar).  It unregisters
 * the PCI device from the EEH subsystem.  I/O errors affecting
 * this device will no longer be detected after this call; thus,
 * i/o errors affecting this slot may leave this device unusable.
 */
void eeh_remove_device(struct pci_dev *dev)
{
        struct eeh_dev *edev;

        if (!dev || !eeh_enabled())
                return;
        edev = pci_dev_to_eeh_dev(dev);

        /* Unregister the device with the EEH/PCI address search system */
        pr_debug("EEH: Removing device %s\n", pci_name(dev));

        if (!edev || !edev->pdev || !edev->pe) {
                pr_debug("EEH: Not referenced !\n");
                return;
        }

        /*
         * During the hotplug for EEH error recovery, we need the EEH
         * device attached to the parent PE in order for BAR restore
         * a bit later. So we keep it for BAR restore and remove it
         * from the parent PE during the BAR resotre.
         */
        edev->pdev = NULL;

        /*
         * The flag "in_error" is used to trace EEH devices for VFs
         * in error state or not. It's set in eeh_report_error(). If
         * it's not set, eeh_report_{reset,resume}() won't be called
         * for the VF EEH device.
         */
        edev->in_error = false;
        dev->dev.archdata.edev = NULL;
        if (!(edev->pe->state & EEH_PE_KEEP))
                eeh_rmv_from_parent_pe(edev);
        else
                edev->mode |= EEH_DEV_DISCONNECTED;

        /*
         * We're removing from the PCI subsystem, that means
         * the PCI device driver can't support EEH or not
         * well. So we rely on hotplug completely to do recovery
         * for the specific PCI device.
         */
        edev->mode |= EEH_DEV_NO_HANDLER;

        eeh_addr_cache_rmv_dev(dev);
        eeh_sysfs_remove_device(dev);
        edev->mode &= ~EEH_DEV_SYSFS;
}

int eeh_unfreeze_pe(struct eeh_pe *pe, bool sw_state)
{
        int ret;

        ret = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
        if (ret) {
                pr_warn("%s: Failure %d enabling IO on PHB#%x-PE#%x\n",
                        __func__, ret, pe->phb->global_number, pe->addr);
                return ret;
        }

        ret = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
        if (ret) {
                pr_warn("%s: Failure %d enabling DMA on PHB#%x-PE#%x\n",
                        __func__, ret, pe->phb->global_number, pe->addr);
                return ret;
        }

        /* Clear software isolated state */
        if (sw_state && (pe->state & EEH_PE_ISOLATED))
                eeh_pe_state_clear(pe, EEH_PE_ISOLATED);

        return ret;
}


static struct pci_device_id eeh_reset_ids[] = {
        { PCI_DEVICE(0x19a2, 0x0710) }, /* Emulex, BE     */
        { PCI_DEVICE(0x10df, 0xe220) }, /* Emulex, Lancer */
        { PCI_DEVICE(0x14e4, 0x1657) }, /* Broadcom BCM5719 */
        { 0 }
};

static int eeh_pe_change_owner(struct eeh_pe *pe)
{
        struct eeh_dev *edev, *tmp;
        struct pci_dev *pdev;
        struct pci_device_id *id;
        int ret;

        /* Check PE state */
        ret = eeh_ops->get_state(pe, NULL);
        if (ret < 0 || ret == EEH_STATE_NOT_SUPPORT)
                return 0;

        /* Unfrozen PE, nothing to do */
        if (eeh_state_active(ret))
                return 0;

        /* Frozen PE, check if it needs PE level reset */
        eeh_pe_for_each_dev(pe, edev, tmp) {
                pdev = eeh_dev_to_pci_dev(edev);
                if (!pdev)
                        continue;

                for (id = &eeh_reset_ids[0]; id->vendor != 0; id++) {
                        if (id->vendor != PCI_ANY_ID &&
                            id->vendor != pdev->vendor)
                                continue;
                        if (id->device != PCI_ANY_ID &&
                            id->device != pdev->device)
                                continue;
                        if (id->subvendor != PCI_ANY_ID &&
                            id->subvendor != pdev->subsystem_vendor)
                                continue;
                        if (id->subdevice != PCI_ANY_ID &&
                            id->subdevice != pdev->subsystem_device)
                                continue;

                        return eeh_pe_reset_and_recover(pe);
                }
        }

        return eeh_unfreeze_pe(pe, true);
}

/**
 * eeh_dev_open - Increase count of pass through devices for PE
 * @pdev: PCI device
 *
 * Increase count of passed through devices for the indicated
 * PE. In the result, the EEH errors detected on the PE won't be
 * reported. The PE owner will be responsible for detection
 * and recovery.
 */
int eeh_dev_open(struct pci_dev *pdev)
{
        struct eeh_dev *edev;
        int ret = -ENODEV;

        mutex_lock(&eeh_dev_mutex);

        /* No PCI device ? */
        if (!pdev)
                goto out;

        /* No EEH device or PE ? */
        edev = pci_dev_to_eeh_dev(pdev);
        if (!edev || !edev->pe)
                goto out;

        /*
         * The PE might have been put into frozen state, but we
         * didn't detect that yet. The passed through PCI devices
         * in frozen PE won't work properly. Clear the frozen state
         * in advance.
         */
        ret = eeh_pe_change_owner(edev->pe);
        if (ret)
                goto out;

        /* Increase PE's pass through count */
        atomic_inc(&edev->pe->pass_dev_cnt);
        mutex_unlock(&eeh_dev_mutex);

        return 0;
out:
        mutex_unlock(&eeh_dev_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(eeh_dev_open);

/**
 * eeh_dev_release - Decrease count of pass through devices for PE
 * @pdev: PCI device
 *
 * Decrease count of pass through devices for the indicated PE. If
 * there is no passed through device in PE, the EEH errors detected
 * on the PE will be reported and handled as usual.
 */
void eeh_dev_release(struct pci_dev *pdev)
{
        struct eeh_dev *edev;

        mutex_lock(&eeh_dev_mutex);

        /* No PCI device ? */
        if (!pdev)
                goto out;

        /* No EEH device ? */
        edev = pci_dev_to_eeh_dev(pdev);
        if (!edev || !edev->pe || !eeh_pe_passed(edev->pe))
                goto out;

        /* Decrease PE's pass through count */
        WARN_ON(atomic_dec_if_positive(&edev->pe->pass_dev_cnt) < 0);
        eeh_pe_change_owner(edev->pe);
out:
        mutex_unlock(&eeh_dev_mutex);
}
EXPORT_SYMBOL(eeh_dev_release);

#ifdef CONFIG_IOMMU_API

static int dev_has_iommu_table(struct device *dev, void *data)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct pci_dev **ppdev = data;

        if (!dev)
                return 0;

        if (dev->iommu_group) {
                *ppdev = pdev;
                return 1;
        }

        return 0;
}

/**
 * eeh_iommu_group_to_pe - Convert IOMMU group to EEH PE
 * @group: IOMMU group
 *
 * The routine is called to convert IOMMU group to EEH PE.
 */
struct eeh_pe *eeh_iommu_group_to_pe(struct iommu_group *group)
{
        struct pci_dev *pdev = NULL;
        struct eeh_dev *edev;
        int ret;

        /* No IOMMU group ? */
        if (!group)
                return NULL;

        ret = iommu_group_for_each_dev(group, &pdev, dev_has_iommu_table);
        if (!ret || !pdev)
                return NULL;

        /* No EEH device or PE ? */
        edev = pci_dev_to_eeh_dev(pdev);
        if (!edev || !edev->pe)
                return NULL;

        return edev->pe;
}
EXPORT_SYMBOL_GPL(eeh_iommu_group_to_pe);

#endif /* CONFIG_IOMMU_API */

/**
 * eeh_pe_set_option - Set options for the indicated PE
 * @pe: EEH PE
 * @option: requested option
 *
 * The routine is called to enable or disable EEH functionality
 * on the indicated PE, to enable IO or DMA for the frozen PE.
 */
int eeh_pe_set_option(struct eeh_pe *pe, int option)
{
        int ret = 0;

        /* Invalid PE ? */
        if (!pe)
                return -ENODEV;

        /*
         * EEH functionality could possibly be disabled, just
         * return error for the case. And the EEH functinality
         * isn't expected to be disabled on one specific PE.
         */
        switch (option) {
        case EEH_OPT_ENABLE:
                if (eeh_enabled()) {
                        ret = eeh_pe_change_owner(pe);
                        break;
                }
                ret = -EIO;
                break;
        case EEH_OPT_DISABLE:
                break;
        case EEH_OPT_THAW_MMIO:
        case EEH_OPT_THAW_DMA:
        case EEH_OPT_FREEZE_PE:
                if (!eeh_ops || !eeh_ops->set_option) {
                        ret = -ENOENT;
                        break;
                }

                ret = eeh_pci_enable(pe, option);
                break;
        default:
                pr_debug("%s: Option %d out of range (%d, %d)\n",
                        __func__, option, EEH_OPT_DISABLE, EEH_OPT_THAW_DMA);
                ret = -EINVAL;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(eeh_pe_set_option);

/**
 * eeh_pe_get_state - Retrieve PE's state
 * @pe: EEH PE
 *
 * Retrieve the PE's state, which includes 3 aspects: enabled
 * DMA, enabled IO and asserted reset.
 */
int eeh_pe_get_state(struct eeh_pe *pe)
{
        int result, ret = 0;
        bool rst_active, dma_en, mmio_en;

        /* Existing PE ? */
        if (!pe)
                return -ENODEV;

        if (!eeh_ops || !eeh_ops->get_state)
                return -ENOENT;

        /*
         * If the parent PE is owned by the host kernel and is undergoing
         * error recovery, we should return the PE state as temporarily
         * unavailable so that the error recovery on the guest is suspended
         * until the recovery completes on the host.
         */
        if (pe->parent &&
            !(pe->state & EEH_PE_REMOVED) &&
            (pe->parent->state & (EEH_PE_ISOLATED | EEH_PE_RECOVERING)))
                return EEH_PE_STATE_UNAVAIL;

        result = eeh_ops->get_state(pe, NULL);
        rst_active = !!(result & EEH_STATE_RESET_ACTIVE);
        dma_en = !!(result & EEH_STATE_DMA_ENABLED);
        mmio_en = !!(result & EEH_STATE_MMIO_ENABLED);

        if (rst_active)
                ret = EEH_PE_STATE_RESET;
        else if (dma_en && mmio_en)
                ret = EEH_PE_STATE_NORMAL;
        else if (!dma_en && !mmio_en)
                ret = EEH_PE_STATE_STOPPED_IO_DMA;
        else if (!dma_en && mmio_en)
                ret = EEH_PE_STATE_STOPPED_DMA;
        else
                ret = EEH_PE_STATE_UNAVAIL;

        return ret;
}
EXPORT_SYMBOL_GPL(eeh_pe_get_state);

static int eeh_pe_reenable_devices(struct eeh_pe *pe)
{
        struct eeh_dev *edev, *tmp;
        struct pci_dev *pdev;
        int ret = 0;

        /* Restore config space */
        eeh_pe_restore_bars(pe);

        /*
         * Reenable PCI devices as the devices passed
         * through are always enabled before the reset.
         */
        eeh_pe_for_each_dev(pe, edev, tmp) {
                pdev = eeh_dev_to_pci_dev(edev);
                if (!pdev)
                        continue;

                ret = pci_reenable_device(pdev);
                if (ret) {
                        pr_warn("%s: Failure %d reenabling %s\n",
                                __func__, ret, pci_name(pdev));
                        return ret;
                }
        }

        /* The PE is still in frozen state */
        return eeh_unfreeze_pe(pe, true);
}


/**
 * eeh_pe_reset - Issue PE reset according to specified type
 * @pe: EEH PE
 * @option: reset type
 *
 * The routine is called to reset the specified PE with the
 * indicated type, either fundamental reset or hot reset.
 * PE reset is the most important part for error recovery.
 */
int eeh_pe_reset(struct eeh_pe *pe, int option)
{
        int ret = 0;

        /* Invalid PE ? */
        if (!pe)
                return -ENODEV;

        if (!eeh_ops || !eeh_ops->set_option || !eeh_ops->reset)
                return -ENOENT;

        switch (option) {
        case EEH_RESET_DEACTIVATE:
                ret = eeh_ops->reset(pe, option);
                eeh_pe_state_clear(pe, EEH_PE_CFG_BLOCKED);
                if (ret)
                        break;

                ret = eeh_pe_reenable_devices(pe);
                break;
        case EEH_RESET_HOT:
        case EEH_RESET_FUNDAMENTAL:
                /*
                 * Proactively freeze the PE to drop all MMIO access
                 * during reset, which should be banned as it's always
                 * cause recursive EEH error.
                 */
                eeh_ops->set_option(pe, EEH_OPT_FREEZE_PE);

                eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
                ret = eeh_ops->reset(pe, option);
                break;
        default:
                pr_debug("%s: Unsupported option %d\n",
                        __func__, option);
                ret = -EINVAL;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(eeh_pe_reset);

/**
 * eeh_pe_configure - Configure PCI bridges after PE reset
 * @pe: EEH PE
 *
 * The routine is called to restore the PCI config space for
 * those PCI devices, especially PCI bridges affected by PE
 * reset issued previously.
 */
int eeh_pe_configure(struct eeh_pe *pe)
{
        int ret = 0;

        /* Invalid PE ? */
        if (!pe)
                return -ENODEV;

        return ret;
}
EXPORT_SYMBOL_GPL(eeh_pe_configure);

/**
 * eeh_pe_inject_err - Injecting the specified PCI error to the indicated PE
 * @pe: the indicated PE
 * @type: error type
 * @function: error function
 * @addr: address
 * @mask: address mask
 *
 * The routine is called to inject the specified PCI error, which
 * is determined by @type and @function, to the indicated PE for
 * testing purpose.
 */
int eeh_pe_inject_err(struct eeh_pe *pe, int type, int func,
                      unsigned long addr, unsigned long mask)
{
        /* Invalid PE ? */
        if (!pe)
                return -ENODEV;

        /* Unsupported operation ? */
        if (!eeh_ops || !eeh_ops->err_inject)
                return -ENOENT;

        /* Check on PCI error type */
        if (type != EEH_ERR_TYPE_32 && type != EEH_ERR_TYPE_64)
                return -EINVAL;

        /* Check on PCI error function */
        if (func < EEH_ERR_FUNC_MIN || func > EEH_ERR_FUNC_MAX)
                return -EINVAL;

        return eeh_ops->err_inject(pe, type, func, addr, mask);
}
EXPORT_SYMBOL_GPL(eeh_pe_inject_err);

static int proc_eeh_show(struct seq_file *m, void *v)
{
        if (!eeh_enabled()) {
                seq_printf(m, "EEH Subsystem is globally disabled\n");
                seq_printf(m, "eeh_total_mmio_ffs=%llu\n", eeh_stats.total_mmio_ffs);
        } else {
                seq_printf(m, "EEH Subsystem is enabled\n");
                seq_printf(m,
                                "no device=%llu\n"
                                "no device node=%llu\n"
                                "no config address=%llu\n"
                                "check not wanted=%llu\n"
                                "eeh_total_mmio_ffs=%llu\n"
                                "eeh_false_positives=%llu\n"
                                "eeh_slot_resets=%llu\n",
                                eeh_stats.no_device,
                                eeh_stats.no_dn,
                                eeh_stats.no_cfg_addr,
                                eeh_stats.ignored_check,
                                eeh_stats.total_mmio_ffs,
                                eeh_stats.false_positives,
                                eeh_stats.slot_resets);
        }

        return 0;
}

#ifdef CONFIG_DEBUG_FS
static int eeh_enable_dbgfs_set(void *data, u64 val)
{
        if (val)
                eeh_clear_flag(EEH_FORCE_DISABLED);
        else
                eeh_add_flag(EEH_FORCE_DISABLED);

        return 0;
}

static int eeh_enable_dbgfs_get(void *data, u64 *val)
{
        if (eeh_enabled())
                *val = 0x1ul;
        else
                *val = 0x0ul;
        return 0;
}

static int eeh_freeze_dbgfs_set(void *data, u64 val)
{
        eeh_max_freezes = val;
        return 0;
}

static int eeh_freeze_dbgfs_get(void *data, u64 *val)
{
        *val = eeh_max_freezes;
        return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(eeh_enable_dbgfs_ops, eeh_enable_dbgfs_get,
                        eeh_enable_dbgfs_set, "0x%llx\n");
DEFINE_SIMPLE_ATTRIBUTE(eeh_freeze_dbgfs_ops, eeh_freeze_dbgfs_get,
                        eeh_freeze_dbgfs_set, "0x%llx\n");
#endif

static int __init eeh_init_proc(void)
{
        if (machine_is(pseries) || machine_is(powernv)) {
                proc_create_single("powerpc/eeh", 0, NULL, proc_eeh_show);
#ifdef CONFIG_DEBUG_FS
                debugfs_create_file("eeh_enable", 0600,
                                    powerpc_debugfs_root, NULL,
                                    &eeh_enable_dbgfs_ops);
                debugfs_create_file("eeh_max_freezes", 0600,
                                    powerpc_debugfs_root, NULL,
                                    &eeh_freeze_dbgfs_ops);
#endif
        }

        return 0;
}
__initcall(eeh_init_proc);