/*
 * The file intends to implement the platform dependent EEH operations on
 * powernv platform. Actually, the powernv was created in order to fully
 * hypervisor support.
 *
 * 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/atomic.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>

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

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

/**
 * powernv_eeh_init - EEH platform dependent initialization
 *
 * EEH platform dependent initialization on powernv
 */
static int powernv_eeh_init(void)
{
        struct pci_controller *hose;
        struct pnv_phb *phb;

        /* We require OPALv3 */
        if (!firmware_has_feature(FW_FEATURE_OPALv3)) {
                pr_warn("%s: OPALv3 is required !\n",
                        __func__);
                return -EINVAL;
        }

        /* Set probe mode */
        eeh_add_flag(EEH_PROBE_MODE_DEV);

        /*
         * P7IOC blocks PCI config access to frozen PE, but PHB3
         * doesn't do that. So we have to selectively enable I/O
         * prior to collecting error log.
         */
        list_for_each_entry(hose, &hose_list, list_node) {
                phb = hose->private_data;

                if (phb->model == PNV_PHB_MODEL_P7IOC)
                        eeh_add_flag(EEH_ENABLE_IO_FOR_LOG);

                /*
                 * PE#0 should be regarded as valid by EEH core
                 * if it's not the reserved one. Currently, we
                 * have the reserved PE#0 and PE#127 for PHB3
                 * and P7IOC separately. So we should regard
                 * PE#0 as valid for P7IOC.
                 */
                if (phb->ioda.reserved_pe != 0)
                        eeh_add_flag(EEH_VALID_PE_ZERO);

                break;
        }

        return 0;
}

/**
 * powernv_eeh_post_init - EEH platform dependent post initialization
 *
 * EEH platform dependent post initialization on powernv. When
 * the function is called, the EEH PEs and devices should have
 * been built. If the I/O cache staff has been built, EEH is
 * ready to supply service.
 */
static int powernv_eeh_post_init(void)
{
        struct pci_controller *hose;
        struct pnv_phb *phb;
        int ret = 0;

        list_for_each_entry(hose, &hose_list, list_node) {
                phb = hose->private_data;

                if (phb->eeh_ops && phb->eeh_ops->post_init) {
                        ret = phb->eeh_ops->post_init(hose);
                        if (ret)
                                break;
                }
        }

        return ret;
}

/**
 * powernv_eeh_dev_probe - Do probe on PCI device
 * @dev: PCI device
 * @flag: unused
 *
 * When EEH module is installed during system boot, all PCI devices
 * are checked one by one to see if it supports EEH. The function
 * is introduced for the purpose. By default, EEH has been enabled
 * on all PCI devices. That's to say, we only need do necessary
 * initialization on the corresponding eeh device and create PE
 * accordingly.
 *
 * It's notable that's unsafe to retrieve the EEH device through
 * the corresponding PCI device. During the PCI device hotplug, which
 * was possiblly triggered by EEH core, the binding between EEH device
 * and the PCI device isn't built yet.
 */
static int powernv_eeh_dev_probe(struct pci_dev *dev, void *flag)
{
        struct pci_controller *hose = pci_bus_to_host(dev->bus);
        struct pnv_phb *phb = hose->private_data;
        struct device_node *dn = pci_device_to_OF_node(dev);
        struct eeh_dev *edev = of_node_to_eeh_dev(dn);
        int ret;

        /*
         * When probing the root bridge, which doesn't have any
         * subordinate PCI devices. We don't have OF node for
         * the root bridge. So it's not reasonable to continue
         * the probing.
         */
        if (!dn || !edev || edev->pe)
                return 0;

        /* Skip for PCI-ISA bridge */
        if ((dev->class >> 8) == PCI_CLASS_BRIDGE_ISA)
                return 0;

        /* Initialize eeh device */
        edev->class_code = dev->class;
        edev->mode      &= 0xFFFFFF00;
        if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
                edev->mode |= EEH_DEV_BRIDGE;
        edev->pcix_cap = pci_find_capability(dev, PCI_CAP_ID_PCIX);
        if (pci_is_pcie(dev)) {
                edev->pcie_cap = pci_pcie_cap(dev);

                if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
                        edev->mode |= EEH_DEV_ROOT_PORT;
                else if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)
                        edev->mode |= EEH_DEV_DS_PORT;

                edev->aer_cap = pci_find_ext_capability(dev,
                                                        PCI_EXT_CAP_ID_ERR);
        }

        edev->config_addr       = ((dev->bus->number << 8) | dev->devfn);
        edev->pe_config_addr    = phb->bdfn_to_pe(phb, dev->bus, dev->devfn & 0xff);

        /* Create PE */
        ret = eeh_add_to_parent_pe(edev);
        if (ret) {
                pr_warn("%s: Can't add PCI dev %s to parent PE (%d)\n",
                        __func__, pci_name(dev), ret);
                return ret;
        }

        /*
         * If the PE contains any one of following adapters, the
         * PCI config space can't be accessed when dumping EEH log.
         * Otherwise, we will run into fenced PHB caused by shortage
         * of outbound credits in the adapter. The PCI config access
         * should be blocked until PE reset. MMIO access is dropped
         * by hardware certainly. In order to drop PCI config requests,
         * one more flag (EEH_PE_CFG_RESTRICTED) is introduced, which
         * will be checked in the backend for PE state retrival. If
         * the PE becomes frozen for the first time and the flag has
         * been set for the PE, we will set EEH_PE_CFG_BLOCKED for
         * that PE to block its config space.
         *
         * Broadcom Austin 4-ports NICs (14e4:1657)
         * Broadcom Shiner 2-ports 10G NICs (14e4:168e)
         */
        if ((dev->vendor == PCI_VENDOR_ID_BROADCOM && dev->device == 0x1657) ||
            (dev->vendor == PCI_VENDOR_ID_BROADCOM && dev->device == 0x168e))
                edev->pe->state |= EEH_PE_CFG_RESTRICTED;

        /*
         * Cache the PE primary bus, which can't be fetched when
         * full hotplug is in progress. In that case, all child
         * PCI devices of the PE are expected to be removed prior
         * to PE reset.
         */
        if (!edev->pe->bus)
                edev->pe->bus = dev->bus;

        /*
         * Enable EEH explicitly so that we will do EEH check
         * while accessing I/O stuff
         */
        eeh_add_flag(EEH_ENABLED);

        /* Save memory bars */
        eeh_save_bars(edev);

        return 0;
}

/**
 * powernv_eeh_set_option - Initialize EEH or MMIO/DMA reenable
 * @pe: EEH PE
 * @option: operation to be issued
 *
 * The function is used to control the EEH functionality globally.
 * Currently, following options are support according to PAPR:
 * Enable EEH, Disable EEH, Enable MMIO and Enable DMA
 */
static int powernv_eeh_set_option(struct eeh_pe *pe, int option)
{
        struct pci_controller *hose = pe->phb;
        struct pnv_phb *phb = hose->private_data;
        int ret = -EEXIST;

        /*
         * What we need do is pass it down for hardware
         * implementation to handle it.
         */
        if (phb->eeh_ops && phb->eeh_ops->set_option)
                ret = phb->eeh_ops->set_option(pe, option);

        return ret;
}

/**
 * powernv_eeh_get_pe_addr - Retrieve PE address
 * @pe: EEH PE
 *
 * Retrieve the PE address according to the given tranditional
 * PCI BDF (Bus/Device/Function) address.
 */
static int powernv_eeh_get_pe_addr(struct eeh_pe *pe)
{
        return pe->addr;
}

/**
 * powernv_eeh_get_state - Retrieve PE state
 * @pe: EEH PE
 * @delay: delay while PE state is temporarily unavailable
 *
 * Retrieve the state of the specified PE. For IODA-compitable
 * platform, it should be retrieved from IODA table. Therefore,
 * we prefer passing down to hardware implementation to handle
 * it.
 */
static int powernv_eeh_get_state(struct eeh_pe *pe, int *delay)
{
        struct pci_controller *hose = pe->phb;
        struct pnv_phb *phb = hose->private_data;
        int ret = EEH_STATE_NOT_SUPPORT;

        if (phb->eeh_ops && phb->eeh_ops->get_state) {
                ret = phb->eeh_ops->get_state(pe);

                /*
                 * If the PE state is temporarily unavailable,
                 * to inform the EEH core delay for default
                 * period (1 second)
                 */
                if (delay) {
                        *delay = 0;
                        if (ret & EEH_STATE_UNAVAILABLE)
                                *delay = 1000;
                }
        }

        return ret;
}

/**
 * powernv_eeh_reset - Reset the specified PE
 * @pe: EEH PE
 * @option: reset option
 *
 * Reset the specified PE
 */
static int powernv_eeh_reset(struct eeh_pe *pe, int option)
{
        struct pci_controller *hose = pe->phb;
        struct pnv_phb *phb = hose->private_data;
        int ret = -EEXIST;

        if (phb->eeh_ops && phb->eeh_ops->reset)
                ret = phb->eeh_ops->reset(pe, option);

        return ret;
}

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

        while (1) {
                ret = powernv_eeh_get_state(pe, &mwait);

                /*
                 * If the PE's state is temporarily unavailable,
                 * we have to wait for the specified time. Otherwise,
                 * the PE's state will be returned immediately.
                 */
                if (ret != EEH_STATE_UNAVAILABLE)
                        return ret;

                max_wait -= mwait;
                if (max_wait <= 0) {
                        pr_warn("%s: Timeout getting PE#%x's state (%d)\n",
                                __func__, pe->addr, max_wait);
                        return EEH_STATE_NOT_SUPPORT;
                }

                msleep(mwait);
        }

        return EEH_STATE_NOT_SUPPORT;
}

/**
 * powernv_eeh_get_log - Retrieve error log
 * @pe: EEH PE
 * @severity: temporary or permanent error log
 * @drv_log: driver log to be combined with retrieved error log
 * @len: length of driver log
 *
 * Retrieve the temporary or permanent error from the PE.
 */
static int powernv_eeh_get_log(struct eeh_pe *pe, int severity,
                               char *drv_log, unsigned long len)
{
        struct pci_controller *hose = pe->phb;
        struct pnv_phb *phb = hose->private_data;
        int ret = -EEXIST;

        if (phb->eeh_ops && phb->eeh_ops->get_log)
                ret = phb->eeh_ops->get_log(pe, severity, drv_log, len);

        return ret;
}

/**
 * powernv_eeh_configure_bridge - Configure PCI bridges in the indicated PE
 * @pe: EEH PE
 *
 * The function will be called to reconfigure the bridges included
 * in the specified PE so that the mulfunctional PE would be recovered
 * again.
 */
static int powernv_eeh_configure_bridge(struct eeh_pe *pe)
{
        struct pci_controller *hose = pe->phb;
        struct pnv_phb *phb = hose->private_data;
        int ret = 0;

        if (phb->eeh_ops && phb->eeh_ops->configure_bridge)
                ret = phb->eeh_ops->configure_bridge(pe);

        return ret;
}

/**
 * powernv_pe_err_inject - Inject specified error to the indicated PE
 * @pe: the indicated PE
 * @type: error type
 * @func: specific error type
 * @addr: address
 * @mask: address mask
 *
 * The routine is called to inject specified error, which is
 * determined by @type and @func, to the indicated PE for
 * testing purpose.
 */
static int powernv_eeh_err_inject(struct eeh_pe *pe, int type, int func,
                                  unsigned long addr, unsigned long mask)
{
        struct pci_controller *hose = pe->phb;
        struct pnv_phb *phb = hose->private_data;
        int ret = -EEXIST;

        if (phb->eeh_ops && phb->eeh_ops->err_inject)
                ret = phb->eeh_ops->err_inject(pe, type, func, addr, mask);

        return ret;
}

static inline bool powernv_eeh_cfg_blocked(struct device_node *dn)
{
        struct eeh_dev *edev = of_node_to_eeh_dev(dn);

        if (!edev || !edev->pe)
                return false;

        if (edev->pe->state & EEH_PE_CFG_BLOCKED)
                return true;

        return false;
}

static int powernv_eeh_read_config(struct device_node *dn,
                                   int where, int size, u32 *val)
{
        if (powernv_eeh_cfg_blocked(dn)) {
                *val = 0xFFFFFFFF;
                return PCIBIOS_SET_FAILED;
        }

        return pnv_pci_cfg_read(dn, where, size, val);
}

static int powernv_eeh_write_config(struct device_node *dn,
                                    int where, int size, u32 val)
{
        if (powernv_eeh_cfg_blocked(dn))
                return PCIBIOS_SET_FAILED;

        return pnv_pci_cfg_write(dn, where, size, val);
}

/**
 * powernv_eeh_next_error - Retrieve next EEH error to handle
 * @pe: Affected PE
 *
 * Using OPAL API, to retrieve next EEH error for EEH core to handle
 */
static int powernv_eeh_next_error(struct eeh_pe **pe)
{
        struct pci_controller *hose;
        struct pnv_phb *phb = NULL;

        list_for_each_entry(hose, &hose_list, list_node) {
                phb = hose->private_data;
                break;
        }

        if (phb && phb->eeh_ops->next_error)
                return phb->eeh_ops->next_error(pe);

        return -EEXIST;
}

static int powernv_eeh_restore_config(struct device_node *dn)
{
        struct eeh_dev *edev = of_node_to_eeh_dev(dn);
        struct pnv_phb *phb;
        s64 ret;

        if (!edev)
                return -EEXIST;

        phb = edev->phb->private_data;
        ret = opal_pci_reinit(phb->opal_id,
                              OPAL_REINIT_PCI_DEV, edev->config_addr);
        if (ret) {
                pr_warn("%s: Can't reinit PCI dev 0x%x (%lld)\n",
                        __func__, edev->config_addr, ret);
                return -EIO;
        }

        return 0;
}

static struct eeh_ops powernv_eeh_ops = {
        .name                   = "powernv",
        .init                   = powernv_eeh_init,
        .post_init              = powernv_eeh_post_init,
        .of_probe               = NULL,
        .dev_probe              = powernv_eeh_dev_probe,
        .set_option             = powernv_eeh_set_option,
        .get_pe_addr            = powernv_eeh_get_pe_addr,
        .get_state              = powernv_eeh_get_state,
        .reset                  = powernv_eeh_reset,
        .wait_state             = powernv_eeh_wait_state,
        .get_log                = powernv_eeh_get_log,
        .configure_bridge       = powernv_eeh_configure_bridge,
        .err_inject             = powernv_eeh_err_inject,
        .read_config            = powernv_eeh_read_config,
        .write_config           = powernv_eeh_write_config,
        .next_error             = powernv_eeh_next_error,
        .restore_config         = powernv_eeh_restore_config
};

/**
 * eeh_powernv_init - Register platform dependent EEH operations
 *
 * EEH initialization on powernv platform. This function should be
 * called before any EEH related functions.
 */
static int __init eeh_powernv_init(void)
{
        int ret = -EINVAL;

        eeh_set_pe_aux_size(PNV_PCI_DIAG_BUF_SIZE);
        ret = eeh_ops_register(&powernv_eeh_ops);
        if (!ret)
                pr_info("EEH: PowerNV platform initialized\n");
        else
                pr_info("EEH: Failed to initialize PowerNV platform (%d)\n", ret);

        return ret;
}
machine_early_initcall(powernv, eeh_powernv_init);