linux/arch/powerpc/platforms/powernv/eeh-ioda.c

/*
 * The file intends to implement the functions needed by EEH, which is
 * built on IODA compliant chip. Actually, lots of functions related
 * to EEH would be built based on the OPAL APIs.
 *
 * Copyright Benjamin Herrenschmidt & Gavin Shan, IBM Corporation 2013.
 *
 * 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.
 */

#include <linux/bootmem.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/msi.h>
#include <linux/notifier.h>
#include <linux/pci.h>
#include <linux/string.h>

#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/io.h>
#include <asm/iommu.h>
#include <asm/msi_bitmap.h>
#include <asm/opal.h>
#include <asm/pci-bridge.h>
#include <asm/ppc-pci.h>
#include <asm/tce.h>

#include "powernv.h"
#include "pci.h"

static int ioda_eeh_nb_init = 0;

static int ioda_eeh_event(struct notifier_block *nb,
			  unsigned long events, void *change)
{
	uint64_t changed_evts = (uint64_t)change;

	/*
	 * We simply send special EEH event if EEH has
	 * been enabled, or clear pending events in
	 * case that we enable EEH soon
	 */
	if (!(changed_evts & OPAL_EVENT_PCI_ERROR) ||
	    !(events & OPAL_EVENT_PCI_ERROR))
		return 0;

	if (eeh_enabled())
		eeh_send_failure_event(NULL);
	else
		opal_notifier_update_evt(OPAL_EVENT_PCI_ERROR, 0x0ul);

	return 0;
}

static struct notifier_block ioda_eeh_nb = {
	.notifier_call	= ioda_eeh_event,
	.next		= NULL,
	.priority	= 0
};

#ifdef CONFIG_DEBUG_FS
static int ioda_eeh_dbgfs_set(void *data, int offset, u64 val)
{
	struct pci_controller *hose = data;
	struct pnv_phb *phb = hose->private_data;

	out_be64(phb->regs + offset, val);
	return 0;
}

static int ioda_eeh_dbgfs_get(void *data, int offset, u64 *val)
{
	struct pci_controller *hose = data;
	struct pnv_phb *phb = hose->private_data;

	*val = in_be64(phb->regs + offset);
	return 0;
}

static int ioda_eeh_outb_dbgfs_set(void *data, u64 val)
{
	return ioda_eeh_dbgfs_set(data, 0xD10, val);
}

static int ioda_eeh_outb_dbgfs_get(void *data, u64 *val)
{
	return ioda_eeh_dbgfs_get(data, 0xD10, val);
}

static int ioda_eeh_inbA_dbgfs_set(void *data, u64 val)
{
	return ioda_eeh_dbgfs_set(data, 0xD90, val);
}

static int ioda_eeh_inbA_dbgfs_get(void *data, u64 *val)
{
	return ioda_eeh_dbgfs_get(data, 0xD90, val);
}

static int ioda_eeh_inbB_dbgfs_set(void *data, u64 val)
{
	return ioda_eeh_dbgfs_set(data, 0xE10, val);
}

static int ioda_eeh_inbB_dbgfs_get(void *data, u64 *val)
{
	return ioda_eeh_dbgfs_get(data, 0xE10, val);
}

DEFINE_SIMPLE_ATTRIBUTE(ioda_eeh_outb_dbgfs_ops, ioda_eeh_outb_dbgfs_get,
			ioda_eeh_outb_dbgfs_set, "0x%llx\n");
DEFINE_SIMPLE_ATTRIBUTE(ioda_eeh_inbA_dbgfs_ops, ioda_eeh_inbA_dbgfs_get,
			ioda_eeh_inbA_dbgfs_set, "0x%llx\n");
DEFINE_SIMPLE_ATTRIBUTE(ioda_eeh_inbB_dbgfs_ops, ioda_eeh_inbB_dbgfs_get,
			ioda_eeh_inbB_dbgfs_set, "0x%llx\n");
#endif /* CONFIG_DEBUG_FS */


/**
 * ioda_eeh_post_init - Chip dependent post initialization
 * @hose: PCI controller
 *
 * The function will be called after eeh PEs and devices
 * have been built. That means the EEH is ready to supply
 * service with I/O cache.
 */
static int ioda_eeh_post_init(struct pci_controller *hose)
{
	struct pnv_phb *phb = hose->private_data;
	int ret;

	/* Register OPAL event notifier */
	if (!ioda_eeh_nb_init) {
		ret = opal_notifier_register(&ioda_eeh_nb);
		if (ret) {
			pr_err("%s: Can't register OPAL event notifier (%d)\n",
			       __func__, ret);
			return ret;
		}

		ioda_eeh_nb_init = 1;
	}

#ifdef CONFIG_DEBUG_FS
	if (!phb->has_dbgfs && phb->dbgfs) {
		phb->has_dbgfs = 1;

		debugfs_create_file("err_injct_outbound", 0600,
				    phb->dbgfs, hose,
				    &ioda_eeh_outb_dbgfs_ops);
		debugfs_create_file("err_injct_inboundA", 0600,
				    phb->dbgfs, hose,
				    &ioda_eeh_inbA_dbgfs_ops);
		debugfs_create_file("err_injct_inboundB", 0600,
				    phb->dbgfs, hose,
				    &ioda_eeh_inbB_dbgfs_ops);
	}
#endif

	/* If EEH is enabled, we're going to rely on that.
	 * Otherwise, we restore to conventional mechanism
	 * to clear frozen PE during PCI config access.
	 */
	if (eeh_enabled())
		phb->flags |= PNV_PHB_FLAG_EEH;
	else
		phb->flags &= ~PNV_PHB_FLAG_EEH;

	return 0;
}

/**
 * ioda_eeh_set_option - Set EEH operation or I/O setting
 * @pe: EEH PE
 * @option: options
 *
 * Enable or disable EEH option for the indicated PE. The
 * function also can be used to enable I/O or DMA for the
 * PE.
 */
static int ioda_eeh_set_option(struct eeh_pe *pe, int option)
{
	s64 ret;
	u32 pe_no;
	struct pci_controller *hose = pe->phb;
	struct pnv_phb *phb = hose->private_data;

	/* Check on PE number */
	if (pe->addr < 0 || pe->addr >= phb->ioda.total_pe) {
		pr_err("%s: PE address %x out of range [0, %x] "
		       "on PHB#%x\n",
			__func__, pe->addr, phb->ioda.total_pe,
			hose->global_number);
		return -EINVAL;
	}

	pe_no = pe->addr;
	switch (option) {
	case EEH_OPT_DISABLE:
		ret = -EEXIST;
		break;
	case EEH_OPT_ENABLE:
		ret = 0;
		break;
	case EEH_OPT_THAW_MMIO:
		ret = opal_pci_eeh_freeze_clear(phb->opal_id, pe_no,
				OPAL_EEH_ACTION_CLEAR_FREEZE_MMIO);
		if (ret) {
			pr_warning("%s: Failed to enable MMIO for "
				   "PHB#%x-PE#%x, err=%lld\n",
				__func__, hose->global_number, pe_no, ret);
			return -EIO;
		}

		break;
	case EEH_OPT_THAW_DMA:
		ret = opal_pci_eeh_freeze_clear(phb->opal_id, pe_no,
				OPAL_EEH_ACTION_CLEAR_FREEZE_DMA);
		if (ret) {
			pr_warning("%s: Failed to enable DMA for "
				   "PHB#%x-PE#%x, err=%lld\n",
				__func__, hose->global_number, pe_no, ret);
			return -EIO;
		}

		break;
	default:
		pr_warning("%s: Invalid option %d\n", __func__, option);
		return -EINVAL;
	}

	return ret;
}

static void ioda_eeh_phb_diag(struct pci_controller *hose)
{
	struct pnv_phb *phb = hose->private_data;
	long rc;

	rc = opal_pci_get_phb_diag_data2(phb->opal_id, phb->diag.blob,
					 PNV_PCI_DIAG_BUF_SIZE);
	if (rc != OPAL_SUCCESS) {
		pr_warning("%s: Failed to get diag-data for PHB#%x (%ld)\n",
			    __func__, hose->global_number, rc);
		return;
	}

	pnv_pci_dump_phb_diag_data(hose, phb->diag.blob);
}

/**
 * ioda_eeh_get_state - Retrieve the state of PE
 * @pe: EEH PE
 *
 * The PE's state should be retrieved from the PEEV, PEST
 * IODA tables. Since the OPAL has exported the function
 * to do it, it'd better to use that.
 */
static int ioda_eeh_get_state(struct eeh_pe *pe)
{
	s64 ret = 0;
	u8 fstate;
	u16 pcierr;
	u32 pe_no;
	int result;
	struct pci_controller *hose = pe->phb;
	struct pnv_phb *phb = hose->private_data;

	/*
	 * Sanity check on PE address. The PHB PE address should
	 * be zero.
	 */
	if (pe->addr < 0 || pe->addr >= phb->ioda.total_pe) {
		pr_err("%s: PE address %x out of range [0, %x] "
		       "on PHB#%x\n",
		       __func__, pe->addr, phb->ioda.total_pe,
		       hose->global_number);
		return EEH_STATE_NOT_SUPPORT;
	}

	/*
	 * If we're in middle of PE reset, return normal
	 * state to keep EEH core going. For PHB reset, we
	 * still expect to have fenced PHB cleared with
	 * PHB reset.
	 */
	if (!(pe->type & EEH_PE_PHB) &&
	    (pe->state & EEH_PE_RESET)) {
		result = (EEH_STATE_MMIO_ACTIVE |
			  EEH_STATE_DMA_ACTIVE |
			  EEH_STATE_MMIO_ENABLED |
			  EEH_STATE_DMA_ENABLED);
		return result;
	}

	/* Retrieve PE status through OPAL */
	pe_no = pe->addr;
	ret = opal_pci_eeh_freeze_status(phb->opal_id, pe_no,
			&fstate, &pcierr, NULL);
	if (ret) {
		pr_err("%s: Failed to get EEH status on "
		       "PHB#%x-PE#%x\n, err=%lld\n",
		       __func__, hose->global_number, pe_no, ret);
		return EEH_STATE_NOT_SUPPORT;
	}

	/* Check PHB status */
	if (pe->type & EEH_PE_PHB) {
		result = 0;
		result &= ~EEH_STATE_RESET_ACTIVE;

		if (pcierr != OPAL_EEH_PHB_ERROR) {
			result |= EEH_STATE_MMIO_ACTIVE;
			result |= EEH_STATE_DMA_ACTIVE;
			result |= EEH_STATE_MMIO_ENABLED;
			result |= EEH_STATE_DMA_ENABLED;
		} else if (!(pe->state & EEH_PE_ISOLATED)) {
			eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
			ioda_eeh_phb_diag(hose);
		}

		return result;
	}

	/* Parse result out */
	result = 0;
	switch (fstate) {
	case OPAL_EEH_STOPPED_NOT_FROZEN:
		result &= ~EEH_STATE_RESET_ACTIVE;
		result |= EEH_STATE_MMIO_ACTIVE;
		result |= EEH_STATE_DMA_ACTIVE;
		result |= EEH_STATE_MMIO_ENABLED;
		result |= EEH_STATE_DMA_ENABLED;
		break;
	case OPAL_EEH_STOPPED_MMIO_FREEZE:
		result &= ~EEH_STATE_RESET_ACTIVE;
		result |= EEH_STATE_DMA_ACTIVE;
		result |= EEH_STATE_DMA_ENABLED;
		break;
	case OPAL_EEH_STOPPED_DMA_FREEZE:
		result &= ~EEH_STATE_RESET_ACTIVE;
		result |= EEH_STATE_MMIO_ACTIVE;
		result |= EEH_STATE_MMIO_ENABLED;
		break;
	case OPAL_EEH_STOPPED_MMIO_DMA_FREEZE:
		result &= ~EEH_STATE_RESET_ACTIVE;
		break;
	case OPAL_EEH_STOPPED_RESET:
		result |= EEH_STATE_RESET_ACTIVE;
		break;
	case OPAL_EEH_STOPPED_TEMP_UNAVAIL:
		result |= EEH_STATE_UNAVAILABLE;
		break;
	case OPAL_EEH_STOPPED_PERM_UNAVAIL:
		result |= EEH_STATE_NOT_SUPPORT;
		break;
	default:
		pr_warning("%s: Unexpected EEH status 0x%x "
			   "on PHB#%x-PE#%x\n",
			   __func__, fstate, hose->global_number, pe_no);
	}

	/* Dump PHB diag-data for frozen PE */
	if (result != EEH_STATE_NOT_SUPPORT &&
	    (result & (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) !=
	    (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE) &&
	    !(pe->state & EEH_PE_ISOLATED)) {
		eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
		ioda_eeh_phb_diag(hose);
	}

	return result;
}

static s64 ioda_eeh_phb_poll(struct pnv_phb *phb)
{
	s64 rc = OPAL_HARDWARE;

	while (1) {
		rc = opal_pci_poll(phb->opal_id);
		if (rc <= 0)
			break;

		if (system_state < SYSTEM_RUNNING)
			udelay(1000 * rc);
		else
			msleep(rc);
	}

	return rc;
}

int ioda_eeh_phb_reset(struct pci_controller *hose, int option)
{
	struct pnv_phb *phb = hose->private_data;
	s64 rc = OPAL_HARDWARE;

	pr_debug("%s: Reset PHB#%x, option=%d\n",
		 __func__, hose->global_number, option);

	/* Issue PHB complete reset request */
	if (option == EEH_RESET_FUNDAMENTAL ||
	    option == EEH_RESET_HOT)
		rc = opal_pci_reset(phb->opal_id,
				OPAL_PHB_COMPLETE,
				OPAL_ASSERT_RESET);
	else if (option == EEH_RESET_DEACTIVATE)
		rc = opal_pci_reset(phb->opal_id,
				OPAL_PHB_COMPLETE,
				OPAL_DEASSERT_RESET);
	if (rc < 0)
		goto out;

	/*
	 * Poll state of the PHB until the request is done
	 * successfully. The PHB reset is usually PHB complete
	 * reset followed by hot reset on root bus. So we also
	 * need the PCI bus settlement delay.
	 */
	rc = ioda_eeh_phb_poll(phb);
	if (option == EEH_RESET_DEACTIVATE) {
		if (system_state < SYSTEM_RUNNING)
			udelay(1000 * EEH_PE_RST_SETTLE_TIME);
		else
			msleep(EEH_PE_RST_SETTLE_TIME);
	}
out:
	if (rc != OPAL_SUCCESS)
		return -EIO;

	return 0;
}

static int ioda_eeh_root_reset(struct pci_controller *hose, int option)
{
	struct pnv_phb *phb = hose->private_data;
	s64 rc = OPAL_SUCCESS;

	pr_debug("%s: Reset PHB#%x, option=%d\n",
		 __func__, hose->global_number, option);

	/*
	 * During the reset deassert time, we needn't care
	 * the reset scope because the firmware does nothing
	 * for fundamental or hot reset during deassert phase.
	 */
	if (option == EEH_RESET_FUNDAMENTAL)
		rc = opal_pci_reset(phb->opal_id,
				OPAL_PCI_FUNDAMENTAL_RESET,
				OPAL_ASSERT_RESET);
	else if (option == EEH_RESET_HOT)
		rc = opal_pci_reset(phb->opal_id,
				OPAL_PCI_HOT_RESET,
				OPAL_ASSERT_RESET);
	else if (option == EEH_RESET_DEACTIVATE)
		rc = opal_pci_reset(phb->opal_id,
				OPAL_PCI_HOT_RESET,
				OPAL_DEASSERT_RESET);
	if (rc < 0)
		goto out;

	/* Poll state of the PHB until the request is done */
	rc = ioda_eeh_phb_poll(phb);
	if (option == EEH_RESET_DEACTIVATE)
		msleep(EEH_PE_RST_SETTLE_TIME);
out:
	if (rc != OPAL_SUCCESS)
		return -EIO;

	return 0;
}

static int ioda_eeh_bridge_reset(struct pci_dev *dev, int option)

{
	struct device_node *dn = pci_device_to_OF_node(dev);
	struct eeh_dev *edev = of_node_to_eeh_dev(dn);
	int aer = edev ? edev->aer_cap : 0;
	u32 ctrl;

	pr_debug("%s: Reset PCI bus %04x:%02x with option %d\n",
		 __func__, pci_domain_nr(dev->bus),
		 dev->bus->number, option);

	switch (option) {
	case EEH_RESET_FUNDAMENTAL:
	case EEH_RESET_HOT:
		/* Don't report linkDown event */
		if (aer) {
			eeh_ops->read_config(dn, aer + PCI_ERR_UNCOR_MASK,
					     4, &ctrl);
			ctrl |= PCI_ERR_UNC_SURPDN;
                        eeh_ops->write_config(dn, aer + PCI_ERR_UNCOR_MASK,
					      4, ctrl);
                }

		eeh_ops->read_config(dn, PCI_BRIDGE_CONTROL, 2, &ctrl);
		ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
		eeh_ops->write_config(dn, PCI_BRIDGE_CONTROL, 2, ctrl);
		msleep(EEH_PE_RST_HOLD_TIME);

		break;
	case EEH_RESET_DEACTIVATE:
		eeh_ops->read_config(dn, PCI_BRIDGE_CONTROL, 2, &ctrl);
		ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
		eeh_ops->write_config(dn, PCI_BRIDGE_CONTROL, 2, ctrl);
		msleep(EEH_PE_RST_SETTLE_TIME);

		/* Continue reporting linkDown event */
		if (aer) {
			eeh_ops->read_config(dn, aer + PCI_ERR_UNCOR_MASK,
					     4, &ctrl);
			ctrl &= ~PCI_ERR_UNC_SURPDN;
			eeh_ops->write_config(dn, aer + PCI_ERR_UNCOR_MASK,
					      4, ctrl);
		}

		break;
	}

	return 0;
}

void pnv_pci_reset_secondary_bus(struct pci_dev *dev)
{
	struct pci_controller *hose;

	if (pci_is_root_bus(dev->bus)) {
		hose = pci_bus_to_host(dev->bus);
		ioda_eeh_root_reset(hose, EEH_RESET_HOT);
		ioda_eeh_root_reset(hose, EEH_RESET_DEACTIVATE);
	} else {
		ioda_eeh_bridge_reset(dev, EEH_RESET_HOT);
		ioda_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE);
	}
}

/**
 * ioda_eeh_reset - Reset the indicated PE
 * @pe: EEH PE
 * @option: reset option
 *
 * Do reset on the indicated PE. For PCI bus sensitive PE,
 * we need to reset the parent p2p bridge. The PHB has to
 * be reinitialized if the p2p bridge is root bridge. For
 * PCI device sensitive PE, we will try to reset the device
 * through FLR. For now, we don't have OPAL APIs to do HARD
 * reset yet, so all reset would be SOFT (HOT) reset.
 */
static int ioda_eeh_reset(struct eeh_pe *pe, int option)
{
	struct pci_controller *hose = pe->phb;
	struct pci_bus *bus;
	int ret;

	/*
	 * For PHB reset, we always have complete reset. For those PEs whose
	 * primary bus derived from root complex (root bus) or root port
	 * (usually bus#1), we apply hot or fundamental reset on the root port.
	 * For other PEs, we always have hot reset on the PE primary bus.
	 *
	 * Here, we have different design to pHyp, which always clear the
	 * frozen state during PE reset. However, the good idea here from
	 * benh is to keep frozen state before we get PE reset done completely
	 * (until BAR restore). With the frozen state, HW drops illegal IO
	 * or MMIO access, which can incur recrusive frozen PE during PE
	 * reset. The side effect is that EEH core has to clear the frozen
	 * state explicitly after BAR restore.
	 */
	if (pe->type & EEH_PE_PHB) {
		ret = ioda_eeh_phb_reset(hose, option);
	} else {
		bus = eeh_pe_bus_get(pe);
		if (pci_is_root_bus(bus) ||
		    pci_is_root_bus(bus->parent))
			ret = ioda_eeh_root_reset(hose, option);
		else
			ret = ioda_eeh_bridge_reset(bus->self, option);
	}

	return ret;
}

/**
 * ioda_eeh_configure_bridge - Configure the PCI bridges for the indicated PE
 * @pe: EEH PE
 *
 * For particular PE, it might have included PCI bridges. In order
 * to make the PE work properly, those PCI bridges should be configured
 * correctly. However, we need do nothing on P7IOC since the reset
 * function will do everything that should be covered by the function.
 */
static int ioda_eeh_configure_bridge(struct eeh_pe *pe)
{
	return 0;
}

static void ioda_eeh_hub_diag_common(struct OpalIoP7IOCErrorData *data)
{
	/* GEM */
	pr_info("  GEM XFIR:        %016llx\n", data->gemXfir);
	pr_info("  GEM RFIR:        %016llx\n", data->gemRfir);
	pr_info("  GEM RIRQFIR:     %016llx\n", data->gemRirqfir);
	pr_info("  GEM Mask:        %016llx\n", data->gemMask);
	pr_info("  GEM RWOF:        %016llx\n", data->gemRwof);

	/* LEM */
	pr_info("  LEM FIR:         %016llx\n", data->lemFir);
	pr_info("  LEM Error Mask:  %016llx\n", data->lemErrMask);
	pr_info("  LEM Action 0:    %016llx\n", data->lemAction0);
	pr_info("  LEM Action 1:    %016llx\n", data->lemAction1);
	pr_info("  LEM WOF:         %016llx\n", data->lemWof);
}

static void ioda_eeh_hub_diag(struct pci_controller *hose)
{
	struct pnv_phb *phb = hose->private_data;
	struct OpalIoP7IOCErrorData *data = &phb->diag.hub_diag;
	long rc;

	rc = opal_pci_get_hub_diag_data(phb->hub_id, data, sizeof(*data));
	if (rc != OPAL_SUCCESS) {
		pr_warning("%s: Failed to get HUB#%llx diag-data (%ld)\n",
			   __func__, phb->hub_id, rc);
		return;
	}

	switch (data->type) {
	case OPAL_P7IOC_DIAG_TYPE_RGC:
		pr_info("P7IOC diag-data for RGC\n\n");
		ioda_eeh_hub_diag_common(data);
		pr_info("  RGC Status:      %016llx\n", data->rgc.rgcStatus);
		pr_info("  RGC LDCP:        %016llx\n", data->rgc.rgcLdcp);
		break;
	case OPAL_P7IOC_DIAG_TYPE_BI:
		pr_info("P7IOC diag-data for BI %s\n\n",
			data->bi.biDownbound ? "Downbound" : "Upbound");
		ioda_eeh_hub_diag_common(data);
		pr_info("  BI LDCP 0:       %016llx\n", data->bi.biLdcp0);
		pr_info("  BI LDCP 1:       %016llx\n", data->bi.biLdcp1);
		pr_info("  BI LDCP 2:       %016llx\n", data->bi.biLdcp2);
		pr_info("  BI Fence Status: %016llx\n", data->bi.biFenceStatus);
		break;
	case OPAL_P7IOC_DIAG_TYPE_CI:
		pr_info("P7IOC diag-data for CI Port %d\\nn",
			data->ci.ciPort);
		ioda_eeh_hub_diag_common(data);
		pr_info("  CI Port Status:  %016llx\n", data->ci.ciPortStatus);
		pr_info("  CI Port LDCP:    %016llx\n", data->ci.ciPortLdcp);
		break;
	case OPAL_P7IOC_DIAG_TYPE_MISC:
		pr_info("P7IOC diag-data for MISC\n\n");
		ioda_eeh_hub_diag_common(data);
		break;
	case OPAL_P7IOC_DIAG_TYPE_I2C:
		pr_info("P7IOC diag-data for I2C\n\n");
		ioda_eeh_hub_diag_common(data);
		break;
	default:
		pr_warning("%s: Invalid type of HUB#%llx diag-data (%d)\n",
			   __func__, phb->hub_id, data->type);
	}
}

static int ioda_eeh_get_pe(struct pci_controller *hose,
			   u16 pe_no, struct eeh_pe **pe)
{
	struct eeh_pe *phb_pe, *dev_pe;
	struct eeh_dev dev;

	/* Find the PHB PE */
	phb_pe = eeh_phb_pe_get(hose);
	if (!phb_pe)
		return -EEXIST;

	/* Find the PE according to PE# */
	memset(&dev, 0, sizeof(struct eeh_dev));
	dev.phb = hose;
	dev.pe_config_addr = pe_no;
	dev_pe = eeh_pe_get(&dev);
	if (!dev_pe) return -EEXIST;

	*pe = dev_pe;
	return 0;
}

/**
 * ioda_eeh_next_error - Retrieve next error for EEH core to handle
 * @pe: The affected PE
 *
 * The function is expected to be called by EEH core while it gets
 * special EEH event (without binding PE). The function calls to
 * OPAL APIs for next error to handle. The informational error is
 * handled internally by platform. However, the dead IOC, dead PHB,
 * fenced PHB and frozen PE should be handled by EEH core eventually.
 */
static int ioda_eeh_next_error(struct eeh_pe **pe)
{
	struct pci_controller *hose;
	struct pnv_phb *phb;
	struct eeh_pe *phb_pe;
	u64 frozen_pe_no;
	u16 err_type, severity;
	long rc;
	int ret = EEH_NEXT_ERR_NONE;

	/*
	 * While running here, it's safe to purge the event queue.
	 * And we should keep the cached OPAL notifier event sychronized
	 * between the kernel and firmware.
	 */
	eeh_remove_event(NULL);
	opal_notifier_update_evt(OPAL_EVENT_PCI_ERROR, 0x0ul);

	list_for_each_entry(hose, &hose_list, list_node) {
		/*
		 * If the subordinate PCI buses of the PHB has been
		 * removed or is exactly under error recovery, we
		 * needn't take care of it any more.
		 */
		phb = hose->private_data;
		phb_pe = eeh_phb_pe_get(hose);
		if (!phb_pe || (phb_pe->state & EEH_PE_ISOLATED))
			continue;

		rc = opal_pci_next_error(phb->opal_id,
				&frozen_pe_no, &err_type, &severity);

		/* If OPAL API returns error, we needn't proceed */
		if (rc != OPAL_SUCCESS) {
			pr_devel("%s: Invalid return value on "
				 "PHB#%x (0x%lx) from opal_pci_next_error",
				 __func__, hose->global_number, rc);
			continue;
		}

		/* If the PHB doesn't have error, stop processing */
		if (err_type == OPAL_EEH_NO_ERROR ||
		    severity == OPAL_EEH_SEV_NO_ERROR) {
			pr_devel("%s: No error found on PHB#%x\n",
				 __func__, hose->global_number);
			continue;
		}

		/*
		 * Processing the error. We're expecting the error with
		 * highest priority reported upon multiple errors on the
		 * specific PHB.
		 */
		pr_devel("%s: Error (%d, %d, %llu) on PHB#%x\n",
			 __func__, err_type, severity,
			 frozen_pe_no, hose->global_number);
		switch (err_type) {
		case OPAL_EEH_IOC_ERROR:
			if (severity == OPAL_EEH_SEV_IOC_DEAD) {
				pr_err("EEH: dead IOC detected\n");
				ret = EEH_NEXT_ERR_DEAD_IOC;
			} else if (severity == OPAL_EEH_SEV_INF) {
				pr_info("EEH: IOC informative error "
					"detected\n");
				ioda_eeh_hub_diag(hose);
				ret = EEH_NEXT_ERR_NONE;
			}

			break;
		case OPAL_EEH_PHB_ERROR:
			if (severity == OPAL_EEH_SEV_PHB_DEAD) {
				*pe = phb_pe;
				pr_err("EEH: dead PHB#%x detected\n",
					hose->global_number);
				ret = EEH_NEXT_ERR_DEAD_PHB;
			} else if (severity == OPAL_EEH_SEV_PHB_FENCED) {
				*pe = phb_pe;
				pr_err("EEH: fenced PHB#%x detected\n",
					hose->global_number);
				ret = EEH_NEXT_ERR_FENCED_PHB;
			} else if (severity == OPAL_EEH_SEV_INF) {
				pr_info("EEH: PHB#%x informative error "
					"detected\n",
					hose->global_number);
				ioda_eeh_phb_diag(hose);
				ret = EEH_NEXT_ERR_NONE;
			}

			break;
		case OPAL_EEH_PE_ERROR:
			/*
			 * If we can't find the corresponding PE, the
			 * PEEV / PEST would be messy. So we force an
			 * fenced PHB so that it can be recovered.
			 *
			 * If the PE has been marked as isolated, that
			 * should have been removed permanently or in
			 * progress with recovery. We needn't report
			 * it again.
			 */
			if (ioda_eeh_get_pe(hose, frozen_pe_no, pe)) {
				*pe = phb_pe;
				pr_err("EEH: Escalated fenced PHB#%x "
				       "detected for PE#%llx\n",
					hose->global_number,
					frozen_pe_no);
				ret = EEH_NEXT_ERR_FENCED_PHB;
			} else if ((*pe)->state & EEH_PE_ISOLATED) {
				ret = EEH_NEXT_ERR_NONE;
			} else {
				pr_err("EEH: Frozen PE#%x on PHB#%x detected\n",
					(*pe)->addr, (*pe)->phb->global_number);
				ret = EEH_NEXT_ERR_FROZEN_PE;
			}

			break;
		default:
			pr_warn("%s: Unexpected error type %d\n",
				__func__, err_type);
		}

		/*
		 * EEH core will try recover from fenced PHB or
		 * frozen PE. In the time for frozen PE, EEH core
		 * enable IO path for that before collecting logs,
		 * but it ruins the site. So we have to dump the
		 * log in advance here.
		 */
		if ((ret == EEH_NEXT_ERR_FROZEN_PE  ||
		    ret == EEH_NEXT_ERR_FENCED_PHB) &&
		    !((*pe)->state & EEH_PE_ISOLATED)) {
			eeh_pe_state_mark(*pe, EEH_PE_ISOLATED);
			ioda_eeh_phb_diag(hose);
		}

		/*
		 * If we have no errors on the specific PHB or only
		 * informative error there, we continue poking it.
		 * Otherwise, we need actions to be taken by upper
		 * layer.
		 */
		if (ret > EEH_NEXT_ERR_INF)
			break;
	}

	return ret;
}

struct pnv_eeh_ops ioda_eeh_ops = {
	.post_init		= ioda_eeh_post_init,
	.set_option		= ioda_eeh_set_option,
	.get_state		= ioda_eeh_get_state,
	.reset			= ioda_eeh_reset,
	.configure_bridge	= ioda_eeh_configure_bridge,
	.next_error		= ioda_eeh_next_error
};