arm64: dts: Revert "specify console via command line"

[linux/fpc-iii.git] / arch / powerpc / kernel / eeh_pe.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * The file intends to implement PE based on the information from
 * platforms. Basically, there have 3 types of PEs: PHB/Bus/Device.
 * All the PEs should be organized as hierarchy tree. The first level
 * of the tree will be associated to existing PHBs since the particular
 * PE is only meaningful in one PHB domain.
 *
 * Copyright Benjamin Herrenschmidt & Gavin Shan, IBM Corporation 2012.
 */

#include <linux/delay.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>

#include <asm/pci-bridge.h>
#include <asm/ppc-pci.h>

static int eeh_pe_aux_size = 0;
static LIST_HEAD(eeh_phb_pe);

/**
 * eeh_set_pe_aux_size - Set PE auxillary data size
 * @size: PE auxillary data size
 *
 * Set PE auxillary data size
 */
void eeh_set_pe_aux_size(int size)
{
        if (size < 0)
                return;

        eeh_pe_aux_size = size;
}

/**
 * eeh_pe_alloc - Allocate PE
 * @phb: PCI controller
 * @type: PE type
 *
 * Allocate PE instance dynamically.
 */
static struct eeh_pe *eeh_pe_alloc(struct pci_controller *phb, int type)
{
        struct eeh_pe *pe;
        size_t alloc_size;

        alloc_size = sizeof(struct eeh_pe);
        if (eeh_pe_aux_size) {
                alloc_size = ALIGN(alloc_size, cache_line_size());
                alloc_size += eeh_pe_aux_size;
        }

        /* Allocate PHB PE */
        pe = kzalloc(alloc_size, GFP_KERNEL);
        if (!pe) return NULL;

        /* Initialize PHB PE */
        pe->type = type;
        pe->phb = phb;
        INIT_LIST_HEAD(&pe->child_list);
        INIT_LIST_HEAD(&pe->edevs);

        pe->data = (void *)pe + ALIGN(sizeof(struct eeh_pe),
                                      cache_line_size());
        return pe;
}

/**
 * eeh_phb_pe_create - Create PHB PE
 * @phb: PCI controller
 *
 * The function should be called while the PHB is detected during
 * system boot or PCI hotplug in order to create PHB PE.
 */
int eeh_phb_pe_create(struct pci_controller *phb)
{
        struct eeh_pe *pe;

        /* Allocate PHB PE */
        pe = eeh_pe_alloc(phb, EEH_PE_PHB);
        if (!pe) {
                pr_err("%s: out of memory!\n", __func__);
                return -ENOMEM;
        }

        /* Put it into the list */
        list_add_tail(&pe->child, &eeh_phb_pe);

        pr_debug("EEH: Add PE for PHB#%x\n", phb->global_number);

        return 0;
}

/**
 * eeh_wait_state - Wait for PE state
 * @pe: EEH PE
 * @max_wait: maximal period in millisecond
 *
 * Wait for the state of associated PE. It might take some time
 * to retrieve the PE's state.
 */
int eeh_wait_state(struct eeh_pe *pe, int max_wait)
{
        int ret;
        int mwait;

        /*
         * According to PAPR, the state of PE might be temporarily
         * unavailable. Under the circumstance, we have to wait
         * for indicated time determined by firmware. The maximal
         * wait time is 5 minutes, which is acquired from the original
         * EEH implementation. Also, the original implementation
         * also defined the minimal wait time as 1 second.
         */
#define EEH_STATE_MIN_WAIT_TIME (1000)
#define EEH_STATE_MAX_WAIT_TIME (300 * 1000)

        while (1) {
                ret = eeh_ops->get_state(pe, &mwait);

                if (ret != EEH_STATE_UNAVAILABLE)
                        return ret;

                if (max_wait <= 0) {
                        pr_warn("%s: Timeout when getting PE's state (%d)\n",
                                __func__, max_wait);
                        return EEH_STATE_NOT_SUPPORT;
                }

                if (mwait < EEH_STATE_MIN_WAIT_TIME) {
                        pr_warn("%s: Firmware returned bad wait value %d\n",
                                __func__, mwait);
                        mwait = EEH_STATE_MIN_WAIT_TIME;
                } else if (mwait > EEH_STATE_MAX_WAIT_TIME) {
                        pr_warn("%s: Firmware returned too long wait value %d\n",
                                __func__, mwait);
                        mwait = EEH_STATE_MAX_WAIT_TIME;
                }

                msleep(min(mwait, max_wait));
                max_wait -= mwait;
        }
}

/**
 * eeh_phb_pe_get - Retrieve PHB PE based on the given PHB
 * @phb: PCI controller
 *
 * The overall PEs form hierarchy tree. The first layer of the
 * hierarchy tree is composed of PHB PEs. The function is used
 * to retrieve the corresponding PHB PE according to the given PHB.
 */
struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb)
{
        struct eeh_pe *pe;

        list_for_each_entry(pe, &eeh_phb_pe, child) {
                /*
                 * Actually, we needn't check the type since
                 * the PE for PHB has been determined when that
                 * was created.
                 */
                if ((pe->type & EEH_PE_PHB) && pe->phb == phb)
                        return pe;
        }

        return NULL;
}

/**
 * eeh_pe_next - Retrieve the next PE in the tree
 * @pe: current PE
 * @root: root PE
 *
 * The function is used to retrieve the next PE in the
 * hierarchy PE tree.
 */
struct eeh_pe *eeh_pe_next(struct eeh_pe *pe, struct eeh_pe *root)
{
        struct list_head *next = pe->child_list.next;

        if (next == &pe->child_list) {
                while (1) {
                        if (pe == root)
                                return NULL;
                        next = pe->child.next;
                        if (next != &pe->parent->child_list)
                                break;
                        pe = pe->parent;
                }
        }

        return list_entry(next, struct eeh_pe, child);
}

/**
 * eeh_pe_traverse - Traverse PEs in the specified PHB
 * @root: root PE
 * @fn: callback
 * @flag: extra parameter to callback
 *
 * The function is used to traverse the specified PE and its
 * child PEs. The traversing is to be terminated once the
 * callback returns something other than NULL, or no more PEs
 * to be traversed.
 */
void *eeh_pe_traverse(struct eeh_pe *root,
                      eeh_pe_traverse_func fn, void *flag)
{
        struct eeh_pe *pe;
        void *ret;

        eeh_for_each_pe(root, pe) {
                ret = fn(pe, flag);
                if (ret) return ret;
        }

        return NULL;
}

/**
 * eeh_pe_dev_traverse - Traverse the devices from the PE
 * @root: EEH PE
 * @fn: function callback
 * @flag: extra parameter to callback
 *
 * The function is used to traverse the devices of the specified
 * PE and its child PEs.
 */
void eeh_pe_dev_traverse(struct eeh_pe *root,
                          eeh_edev_traverse_func fn, void *flag)
{
        struct eeh_pe *pe;
        struct eeh_dev *edev, *tmp;

        if (!root) {
                pr_warn("%s: Invalid PE %p\n",
                        __func__, root);
                return;
        }

        /* Traverse root PE */
        eeh_for_each_pe(root, pe)
                eeh_pe_for_each_dev(pe, edev, tmp)
                        fn(edev, flag);
}

/**
 * __eeh_pe_get - Check the PE address
 * @data: EEH PE
 * @flag: EEH device
 *
 * For one particular PE, it can be identified by PE address
 * or tranditional BDF address. BDF address is composed of
 * Bus/Device/Function number. The extra data referred by flag
 * indicates which type of address should be used.
 */
struct eeh_pe_get_flag {
        int pe_no;
        int config_addr;
};

static void *__eeh_pe_get(struct eeh_pe *pe, void *flag)
{
        struct eeh_pe_get_flag *tmp = (struct eeh_pe_get_flag *) flag;

        /* Unexpected PHB PE */
        if (pe->type & EEH_PE_PHB)
                return NULL;

        /*
         * We prefer PE address. For most cases, we should
         * have non-zero PE address
         */
        if (eeh_has_flag(EEH_VALID_PE_ZERO)) {
                if (tmp->pe_no == pe->addr)
                        return pe;
        } else {
                if (tmp->pe_no &&
                    (tmp->pe_no == pe->addr))
                        return pe;
        }

        /* Try BDF address */
        if (tmp->config_addr &&
           (tmp->config_addr == pe->config_addr))
                return pe;

        return NULL;
}

/**
 * eeh_pe_get - Search PE based on the given address
 * @phb: PCI controller
 * @pe_no: PE number
 * @config_addr: Config address
 *
 * Search the corresponding PE based on the specified address which
 * is included in the eeh device. The function is used to check if
 * the associated PE has been created against the PE address. It's
 * notable that the PE address has 2 format: traditional PE address
 * which is composed of PCI bus/device/function number, or unified
 * PE address.
 */
struct eeh_pe *eeh_pe_get(struct pci_controller *phb,
                int pe_no, int config_addr)
{
        struct eeh_pe *root = eeh_phb_pe_get(phb);
        struct eeh_pe_get_flag tmp = { pe_no, config_addr };
        struct eeh_pe *pe;

        pe = eeh_pe_traverse(root, __eeh_pe_get, &tmp);

        return pe;
}

/**
 * eeh_pe_get_parent - Retrieve the parent PE
 * @edev: EEH device
 *
 * The whole PEs existing in the system are organized as hierarchy
 * tree. The function is used to retrieve the parent PE according
 * to the parent EEH device.
 */
static struct eeh_pe *eeh_pe_get_parent(struct eeh_dev *edev)
{
        struct eeh_dev *parent;
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);

        /*
         * It might have the case for the indirect parent
         * EEH device already having associated PE, but
         * the direct parent EEH device doesn't have yet.
         */
        if (edev->physfn)
                pdn = pci_get_pdn(edev->physfn);
        else
                pdn = pdn ? pdn->parent : NULL;
        while (pdn) {
                /* We're poking out of PCI territory */
                parent = pdn_to_eeh_dev(pdn);
                if (!parent)
                        return NULL;

                if (parent->pe)
                        return parent->pe;

                pdn = pdn->parent;
        }

        return NULL;
}

/**
 * eeh_add_to_parent_pe - Add EEH device to parent PE
 * @edev: EEH device
 *
 * Add EEH device to the parent PE. If the parent PE already
 * exists, the PE type will be changed to EEH_PE_BUS. Otherwise,
 * we have to create new PE to hold the EEH device and the new
 * PE will be linked to its parent PE as well.
 */
int eeh_add_to_parent_pe(struct eeh_dev *edev)
{
        struct eeh_pe *pe, *parent;
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);
        int config_addr = (pdn->busno << 8) | (pdn->devfn);

        /* Check if the PE number is valid */
        if (!eeh_has_flag(EEH_VALID_PE_ZERO) && !edev->pe_config_addr) {
                eeh_edev_err(edev, "PE#0 is invalid for this PHB!\n");
                return -EINVAL;
        }

        /*
         * Search the PE has been existing or not according
         * to the PE address. If that has been existing, the
         * PE should be composed of PCI bus and its subordinate
         * components.
         */
        pe = eeh_pe_get(pdn->phb, edev->pe_config_addr, config_addr);
        if (pe) {
                if (pe->type & EEH_PE_INVALID) {
                        list_add_tail(&edev->entry, &pe->edevs);
                        edev->pe = pe;
                        /*
                         * We're running to here because of PCI hotplug caused by
                         * EEH recovery. We need clear EEH_PE_INVALID until the top.
                         */
                        parent = pe;
                        while (parent) {
                                if (!(parent->type & EEH_PE_INVALID))
                                        break;
                                parent->type &= ~EEH_PE_INVALID;
                                parent = parent->parent;
                        }

                        eeh_edev_dbg(edev,
                                     "Added to device PE (parent: PE#%x)\n",
                                     pe->parent->addr);
                } else {
                        /* Mark the PE as type of PCI bus */
                        pe->type = EEH_PE_BUS;
                        edev->pe = pe;

                        /* Put the edev to PE */
                        list_add_tail(&edev->entry, &pe->edevs);
                        eeh_edev_dbg(edev, "Added to bus PE\n");
                }
                return 0;
        }

        /* Create a new EEH PE */
        if (edev->physfn)
                pe = eeh_pe_alloc(pdn->phb, EEH_PE_VF);
        else
                pe = eeh_pe_alloc(pdn->phb, EEH_PE_DEVICE);
        if (!pe) {
                pr_err("%s: out of memory!\n", __func__);
                return -ENOMEM;
        }
        pe->addr        = edev->pe_config_addr;
        pe->config_addr = config_addr;

        /*
         * Put the new EEH PE into hierarchy tree. If the parent
         * can't be found, the newly created PE will be attached
         * to PHB directly. Otherwise, we have to associate the
         * PE with its parent.
         */
        parent = eeh_pe_get_parent(edev);
        if (!parent) {
                parent = eeh_phb_pe_get(pdn->phb);
                if (!parent) {
                        pr_err("%s: No PHB PE is found (PHB Domain=%d)\n",
                                __func__, pdn->phb->global_number);
                        edev->pe = NULL;
                        kfree(pe);
                        return -EEXIST;
                }
        }
        pe->parent = parent;

        /*
         * Put the newly created PE into the child list and
         * link the EEH device accordingly.
         */
        list_add_tail(&pe->child, &parent->child_list);
        list_add_tail(&edev->entry, &pe->edevs);
        edev->pe = pe;
        eeh_edev_dbg(edev, "Added to device PE (parent: PE#%x)\n",
                     pe->parent->addr);

        return 0;
}

/**
 * eeh_rmv_from_parent_pe - Remove one EEH device from the associated PE
 * @edev: EEH device
 *
 * The PE hierarchy tree might be changed when doing PCI hotplug.
 * Also, the PCI devices or buses could be removed from the system
 * during EEH recovery. So we have to call the function remove the
 * corresponding PE accordingly if necessary.
 */
int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
{
        struct eeh_pe *pe, *parent, *child;
        bool keep, recover;
        int cnt;

        pe = eeh_dev_to_pe(edev);
        if (!pe) {
                eeh_edev_dbg(edev, "No PE found for device.\n");
                return -EEXIST;
        }

        /* Remove the EEH device */
        edev->pe = NULL;
        list_del(&edev->entry);

        /*
         * Check if the parent PE includes any EEH devices.
         * If not, we should delete that. Also, we should
         * delete the parent PE if it doesn't have associated
         * child PEs and EEH devices.
         */
        while (1) {
                parent = pe->parent;

                /* PHB PEs should never be removed */
                if (pe->type & EEH_PE_PHB)
                        break;

                /*
                 * XXX: KEEP is set while resetting a PE. I don't think it's
                 * ever set without RECOVERING also being set. I could
                 * be wrong though so catch that with a WARN.
                 */
                keep = !!(pe->state & EEH_PE_KEEP);
                recover = !!(pe->state & EEH_PE_RECOVERING);
                WARN_ON(keep && !recover);

                if (!keep && !recover) {
                        if (list_empty(&pe->edevs) &&
                            list_empty(&pe->child_list)) {
                                list_del(&pe->child);
                                kfree(pe);
                        } else {
                                break;
                        }
                } else {
                        /*
                         * Mark the PE as invalid. At the end of the recovery
                         * process any invalid PEs will be garbage collected.
                         *
                         * We need to delay the free()ing of them since we can
                         * remove edev's while traversing the PE tree which
                         * might trigger the removal of a PE and we can't
                         * deal with that (yet).
                         */
                        if (list_empty(&pe->edevs)) {
                                cnt = 0;
                                list_for_each_entry(child, &pe->child_list, child) {
                                        if (!(child->type & EEH_PE_INVALID)) {
                                                cnt++;
                                                break;
                                        }
                                }

                                if (!cnt)
                                        pe->type |= EEH_PE_INVALID;
                                else
                                        break;
                        }
                }

                pe = parent;
        }

        return 0;
}

/**
 * eeh_pe_update_time_stamp - Update PE's frozen time stamp
 * @pe: EEH PE
 *
 * We have time stamp for each PE to trace its time of getting
 * frozen in last hour. The function should be called to update
 * the time stamp on first error of the specific PE. On the other
 * handle, we needn't account for errors happened in last hour.
 */
void eeh_pe_update_time_stamp(struct eeh_pe *pe)
{
        time64_t tstamp;

        if (!pe) return;

        if (pe->freeze_count <= 0) {
                pe->freeze_count = 0;
                pe->tstamp = ktime_get_seconds();
        } else {
                tstamp = ktime_get_seconds();
                if (tstamp - pe->tstamp > 3600) {
                        pe->tstamp = tstamp;
                        pe->freeze_count = 0;
                }
        }
}

/**
 * eeh_pe_state_mark - Mark specified state for PE and its associated device
 * @pe: EEH PE
 *
 * EEH error affects the current PE and its child PEs. The function
 * is used to mark appropriate state for the affected PEs and the
 * associated devices.
 */
void eeh_pe_state_mark(struct eeh_pe *root, int state)
{
        struct eeh_pe *pe;

        eeh_for_each_pe(root, pe)
                if (!(pe->state & EEH_PE_REMOVED))
                        pe->state |= state;
}
EXPORT_SYMBOL_GPL(eeh_pe_state_mark);

/**
 * eeh_pe_mark_isolated
 * @pe: EEH PE
 *
 * Record that a PE has been isolated by marking the PE and it's children as
 * EEH_PE_ISOLATED (and EEH_PE_CFG_BLOCKED, if required) and their PCI devices
 * as pci_channel_io_frozen.
 */
void eeh_pe_mark_isolated(struct eeh_pe *root)
{
        struct eeh_pe *pe;
        struct eeh_dev *edev;
        struct pci_dev *pdev;

        eeh_pe_state_mark(root, EEH_PE_ISOLATED);
        eeh_for_each_pe(root, pe) {
                list_for_each_entry(edev, &pe->edevs, entry) {
                        pdev = eeh_dev_to_pci_dev(edev);
                        if (pdev)
                                pdev->error_state = pci_channel_io_frozen;
                }
                /* Block PCI config access if required */
                if (pe->state & EEH_PE_CFG_RESTRICTED)
                        pe->state |= EEH_PE_CFG_BLOCKED;
        }
}
EXPORT_SYMBOL_GPL(eeh_pe_mark_isolated);

static void __eeh_pe_dev_mode_mark(struct eeh_dev *edev, void *flag)
{
        int mode = *((int *)flag);

        edev->mode |= mode;
}

/**
 * eeh_pe_dev_state_mark - Mark state for all device under the PE
 * @pe: EEH PE
 *
 * Mark specific state for all child devices of the PE.
 */
void eeh_pe_dev_mode_mark(struct eeh_pe *pe, int mode)
{
        eeh_pe_dev_traverse(pe, __eeh_pe_dev_mode_mark, &mode);
}

/**
 * eeh_pe_state_clear - Clear state for the PE
 * @data: EEH PE
 * @state: state
 * @include_passed: include passed-through devices?
 *
 * The function is used to clear the indicated state from the
 * given PE. Besides, we also clear the check count of the PE
 * as well.
 */
void eeh_pe_state_clear(struct eeh_pe *root, int state, bool include_passed)
{
        struct eeh_pe *pe;
        struct eeh_dev *edev, *tmp;
        struct pci_dev *pdev;

        eeh_for_each_pe(root, pe) {
                /* Keep the state of permanently removed PE intact */
                if (pe->state & EEH_PE_REMOVED)
                        continue;

                if (!include_passed && eeh_pe_passed(pe))
                        continue;

                pe->state &= ~state;

                /*
                 * Special treatment on clearing isolated state. Clear
                 * check count since last isolation and put all affected
                 * devices to normal state.
                 */
                if (!(state & EEH_PE_ISOLATED))
                        continue;

                pe->check_count = 0;
                eeh_pe_for_each_dev(pe, edev, tmp) {
                        pdev = eeh_dev_to_pci_dev(edev);
                        if (!pdev)
                                continue;

                        pdev->error_state = pci_channel_io_normal;
                }

                /* Unblock PCI config access if required */
                if (pe->state & EEH_PE_CFG_RESTRICTED)
                        pe->state &= ~EEH_PE_CFG_BLOCKED;
        }
}

/*
 * Some PCI bridges (e.g. PLX bridges) have primary/secondary
 * buses assigned explicitly by firmware, and we probably have
 * lost that after reset. So we have to delay the check until
 * the PCI-CFG registers have been restored for the parent
 * bridge.
 *
 * Don't use normal PCI-CFG accessors, which probably has been
 * blocked on normal path during the stage. So we need utilize
 * eeh operations, which is always permitted.
 */
static void eeh_bridge_check_link(struct eeh_dev *edev)
{
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);
        int cap;
        uint32_t val;
        int timeout = 0;

        /*
         * We only check root port and downstream ports of
         * PCIe switches
         */
        if (!(edev->mode & (EEH_DEV_ROOT_PORT | EEH_DEV_DS_PORT)))
                return;

        eeh_edev_dbg(edev, "Checking PCIe link...\n");

        /* Check slot status */
        cap = edev->pcie_cap;
        eeh_ops->read_config(pdn, cap + PCI_EXP_SLTSTA, 2, &val);
        if (!(val & PCI_EXP_SLTSTA_PDS)) {
                eeh_edev_dbg(edev, "No card in the slot (0x%04x) !\n", val);
                return;
        }

        /* Check power status if we have the capability */
        eeh_ops->read_config(pdn, cap + PCI_EXP_SLTCAP, 2, &val);
        if (val & PCI_EXP_SLTCAP_PCP) {
                eeh_ops->read_config(pdn, cap + PCI_EXP_SLTCTL, 2, &val);
                if (val & PCI_EXP_SLTCTL_PCC) {
                        eeh_edev_dbg(edev, "In power-off state, power it on ...\n");
                        val &= ~(PCI_EXP_SLTCTL_PCC | PCI_EXP_SLTCTL_PIC);
                        val |= (0x0100 & PCI_EXP_SLTCTL_PIC);
                        eeh_ops->write_config(pdn, cap + PCI_EXP_SLTCTL, 2, val);
                        msleep(2 * 1000);
                }
        }

        /* Enable link */
        eeh_ops->read_config(pdn, cap + PCI_EXP_LNKCTL, 2, &val);
        val &= ~PCI_EXP_LNKCTL_LD;
        eeh_ops->write_config(pdn, cap + PCI_EXP_LNKCTL, 2, val);

        /* Check link */
        eeh_ops->read_config(pdn, cap + PCI_EXP_LNKCAP, 4, &val);
        if (!(val & PCI_EXP_LNKCAP_DLLLARC)) {
                eeh_edev_dbg(edev, "No link reporting capability (0x%08x) \n", val);
                msleep(1000);
                return;
        }

        /* Wait the link is up until timeout (5s) */
        timeout = 0;
        while (timeout < 5000) {
                msleep(20);
                timeout += 20;

                eeh_ops->read_config(pdn, cap + PCI_EXP_LNKSTA, 2, &val);
                if (val & PCI_EXP_LNKSTA_DLLLA)
                        break;
        }

        if (val & PCI_EXP_LNKSTA_DLLLA)
                eeh_edev_dbg(edev, "Link up (%s)\n",
                         (val & PCI_EXP_LNKSTA_CLS_2_5GB) ? "2.5GB" : "5GB");
        else
                eeh_edev_dbg(edev, "Link not ready (0x%04x)\n", val);
}

#define BYTE_SWAP(OFF)  (8*((OFF)/4)+3-(OFF))
#define SAVED_BYTE(OFF) (((u8 *)(edev->config_space))[BYTE_SWAP(OFF)])

static void eeh_restore_bridge_bars(struct eeh_dev *edev)
{
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);
        int i;

        /*
         * Device BARs: 0x10 - 0x18
         * Bus numbers and windows: 0x18 - 0x30
         */
        for (i = 4; i < 13; i++)
                eeh_ops->write_config(pdn, i*4, 4, edev->config_space[i]);
        /* Rom: 0x38 */
        eeh_ops->write_config(pdn, 14*4, 4, edev->config_space[14]);

        /* Cache line & Latency timer: 0xC 0xD */
        eeh_ops->write_config(pdn, PCI_CACHE_LINE_SIZE, 1,
                SAVED_BYTE(PCI_CACHE_LINE_SIZE));
        eeh_ops->write_config(pdn, PCI_LATENCY_TIMER, 1,
                SAVED_BYTE(PCI_LATENCY_TIMER));
        /* Max latency, min grant, interrupt ping and line: 0x3C */
        eeh_ops->write_config(pdn, 15*4, 4, edev->config_space[15]);

        /* PCI Command: 0x4 */
        eeh_ops->write_config(pdn, PCI_COMMAND, 4, edev->config_space[1] |
                              PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);

        /* Check the PCIe link is ready */
        eeh_bridge_check_link(edev);
}

static void eeh_restore_device_bars(struct eeh_dev *edev)
{
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);
        int i;
        u32 cmd;

        for (i = 4; i < 10; i++)
                eeh_ops->write_config(pdn, i*4, 4, edev->config_space[i]);
        /* 12 == Expansion ROM Address */
        eeh_ops->write_config(pdn, 12*4, 4, edev->config_space[12]);

        eeh_ops->write_config(pdn, PCI_CACHE_LINE_SIZE, 1,
                SAVED_BYTE(PCI_CACHE_LINE_SIZE));
        eeh_ops->write_config(pdn, PCI_LATENCY_TIMER, 1,
                SAVED_BYTE(PCI_LATENCY_TIMER));

        /* max latency, min grant, interrupt pin and line */
        eeh_ops->write_config(pdn, 15*4, 4, edev->config_space[15]);

        /*
         * Restore PERR & SERR bits, some devices require it,
         * don't touch the other command bits
         */
        eeh_ops->read_config(pdn, PCI_COMMAND, 4, &cmd);
        if (edev->config_space[1] & PCI_COMMAND_PARITY)
                cmd |= PCI_COMMAND_PARITY;
        else
                cmd &= ~PCI_COMMAND_PARITY;
        if (edev->config_space[1] & PCI_COMMAND_SERR)
                cmd |= PCI_COMMAND_SERR;
        else
                cmd &= ~PCI_COMMAND_SERR;
        eeh_ops->write_config(pdn, PCI_COMMAND, 4, cmd);
}

/**
 * eeh_restore_one_device_bars - Restore the Base Address Registers for one device
 * @data: EEH device
 * @flag: Unused
 *
 * Loads the PCI configuration space base address registers,
 * the expansion ROM base address, the latency timer, and etc.
 * from the saved values in the device node.
 */
static void eeh_restore_one_device_bars(struct eeh_dev *edev, void *flag)
{
        struct pci_dn *pdn = eeh_dev_to_pdn(edev);

        /* Do special restore for bridges */
        if (edev->mode & EEH_DEV_BRIDGE)
                eeh_restore_bridge_bars(edev);
        else
                eeh_restore_device_bars(edev);

        if (eeh_ops->restore_config && pdn)
                eeh_ops->restore_config(pdn);
}

/**
 * eeh_pe_restore_bars - Restore the PCI config space info
 * @pe: EEH PE
 *
 * This routine performs a recursive walk to the children
 * of this device as well.
 */
void eeh_pe_restore_bars(struct eeh_pe *pe)
{
        /*
         * We needn't take the EEH lock since eeh_pe_dev_traverse()
         * will take that.
         */
        eeh_pe_dev_traverse(pe, eeh_restore_one_device_bars, NULL);
}

/**
 * eeh_pe_loc_get - Retrieve location code binding to the given PE
 * @pe: EEH PE
 *
 * Retrieve the location code of the given PE. If the primary PE bus
 * is root bus, we will grab location code from PHB device tree node
 * or root port. Otherwise, the upstream bridge's device tree node
 * of the primary PE bus will be checked for the location code.
 */
const char *eeh_pe_loc_get(struct eeh_pe *pe)
{
        struct pci_bus *bus = eeh_pe_bus_get(pe);
        struct device_node *dn;
        const char *loc = NULL;

        while (bus) {
                dn = pci_bus_to_OF_node(bus);
                if (!dn) {
                        bus = bus->parent;
                        continue;
                }

                if (pci_is_root_bus(bus))
                        loc = of_get_property(dn, "ibm,io-base-loc-code", NULL);
                else
                        loc = of_get_property(dn, "ibm,slot-location-code",
                                              NULL);

                if (loc)
                        return loc;

                bus = bus->parent;
        }

        return "N/A";
}

/**
 * eeh_pe_bus_get - Retrieve PCI bus according to the given PE
 * @pe: EEH PE
 *
 * Retrieve the PCI bus according to the given PE. Basically,
 * there're 3 types of PEs: PHB/Bus/Device. For PHB PE, the
 * primary PCI bus will be retrieved. The parent bus will be
 * returned for BUS PE. However, we don't have associated PCI
 * bus for DEVICE PE.
 */
struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
{
        struct eeh_dev *edev;
        struct pci_dev *pdev;

        if (pe->type & EEH_PE_PHB)
                return pe->phb->bus;

        /* The primary bus might be cached during probe time */
        if (pe->state & EEH_PE_PRI_BUS)
                return pe->bus;

        /* Retrieve the parent PCI bus of first (top) PCI device */
        edev = list_first_entry_or_null(&pe->edevs, struct eeh_dev, entry);
        pdev = eeh_dev_to_pci_dev(edev);
        if (pdev)
                return pdev->bus;

        return NULL;
}