// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI Hot Plug Controller Driver for RPA-compliant PPC64 platform.
 * Copyright (C) 2003 Linda Xie <lxie@us.ibm.com>
 *
 * All rights reserved.
 *
 * Send feedback to <lxie@us.ibm.com>
 *
 */
#include <linux/of.h>
#include <linux/pci.h>
#include <linux/string.h>

#include <asm/pci-bridge.h>
#include <asm/rtas.h>
#include <asm/machdep.h>

#include "../pci.h"             /* for pci_add_new_bus */
#include "rpaphp.h"

/*
 * RTAS call get-sensor-state(DR_ENTITY_SENSE) return values as per PAPR:
 * -- generic return codes ---
 *    -1: Hardware Error
 *    -2: RTAS_BUSY
 *    -3: Invalid sensor. RTAS Parameter Error.
 * -- rtas_get_sensor function specific return codes ---
 * -9000: Need DR entity to be powered up and unisolated before RTAS call
 * -9001: Need DR entity to be powered up, but not unisolated, before RTAS call
 * -9002: DR entity unusable
 *  990x: Extended delay - where x is a number in the range of 0-5
 */
#define RTAS_SLOT_UNISOLATED            -9000
#define RTAS_SLOT_NOT_UNISOLATED        -9001
#define RTAS_SLOT_NOT_USABLE            -9002

static int rtas_get_sensor_errno(int rtas_rc)
{
        switch (rtas_rc) {
        case 0:
                /* Success case */
                return 0;
        case RTAS_SLOT_UNISOLATED:
        case RTAS_SLOT_NOT_UNISOLATED:
                return -EFAULT;
        case RTAS_SLOT_NOT_USABLE:
                return -ENODEV;
        case RTAS_BUSY:
        case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
                return -EBUSY;
        default:
                return rtas_error_rc(rtas_rc);
        }
}

/*
 * get_adapter_status() can be called by the EEH handler during EEH recovery.
 * On certain PHB failures, the RTAS call rtas_call(get-sensor-state) returns
 * extended busy error (9902) until PHB is recovered by pHyp. The RTAS call
 * interface rtas_get_sensor() loops over the RTAS call on extended delay
 * return code (9902) until the return value is either success (0) or error
 * (-1). This causes the EEH handler to get stuck for ~6 seconds before it
 * could notify that the PCI error has been detected and stop any active
 * operations. This sometimes causes EEH recovery to fail. To avoid this issue,
 * invoke rtas_call(get-sensor-state) directly if the respective PE is in EEH
 * recovery state and return -EBUSY error based on RTAS return status. This
 * will help the EEH handler to notify the driver about the PCI error
 * immediately and successfully proceed with EEH recovery steps.
 */

static int __rpaphp_get_sensor_state(struct slot *slot, int *state)
{
        int rc;
        int token = rtas_token("get-sensor-state");
        struct pci_dn *pdn;
        struct eeh_pe *pe;
        struct pci_controller *phb = PCI_DN(slot->dn)->phb;

        if (token == RTAS_UNKNOWN_SERVICE)
                return -ENOENT;

        /*
         * Fallback to existing method for empty slot or PE isn't in EEH
         * recovery.
         */
        pdn = list_first_entry_or_null(&PCI_DN(phb->dn)->child_list,
                                        struct pci_dn, list);
        if (!pdn)
                goto fallback;

        pe = eeh_dev_to_pe(pdn->edev);
        if (pe && (pe->state & EEH_PE_RECOVERING)) {
                rc = rtas_call(token, 2, 2, state, DR_ENTITY_SENSE,
                               slot->index);
                return rtas_get_sensor_errno(rc);
        }
fallback:
        return rtas_get_sensor(DR_ENTITY_SENSE, slot->index, state);
}

int rpaphp_get_sensor_state(struct slot *slot, int *state)
{
        int rc;
        int setlevel;

        rc = __rpaphp_get_sensor_state(slot, state);

        if (rc < 0) {
                if (rc == -EFAULT || rc == -EEXIST) {
                        dbg("%s: slot must be power up to get sensor-state\n",
                            __func__);

                        /* some slots have to be powered up
                         * before get-sensor will succeed.
                         */
                        rc = rtas_set_power_level(slot->power_domain, POWER_ON,
                                                  &setlevel);
                        if (rc < 0) {
                                dbg("%s: power on slot[%s] failed rc=%d.\n",
                                    __func__, slot->name, rc);
                        } else {
                                rc = __rpaphp_get_sensor_state(slot, state);
                        }
                } else if (rc == -ENODEV)
                        info("%s: slot is unusable\n", __func__);
                else
                        err("%s failed to get sensor state\n", __func__);
        }
        return rc;
}

/**
 * rpaphp_enable_slot - record slot state, config pci device
 * @slot: target &slot
 *
 * Initialize values in the slot structure to indicate if there is a pci card
 * plugged into the slot. If the slot is not empty, run the pcibios routine
 * to get pcibios stuff correctly set up.
 */
int rpaphp_enable_slot(struct slot *slot)
{
        int rc, level, state;
        struct pci_bus *bus;

        slot->state = EMPTY;

        /* Find out if the power is turned on for the slot */
        rc = rtas_get_power_level(slot->power_domain, &level);
        if (rc)
                return rc;

        /* Figure out if there is an adapter in the slot */
        rc = rpaphp_get_sensor_state(slot, &state);
        if (rc)
                return rc;

        bus = pci_find_bus_by_node(slot->dn);
        if (!bus) {
                err("%s: no pci_bus for dn %pOF\n", __func__, slot->dn);
                return -EINVAL;
        }

        slot->bus = bus;
        slot->pci_devs = &bus->devices;

        /* if there's an adapter in the slot, go add the pci devices */
        if (state == PRESENT) {
                slot->state = NOT_CONFIGURED;

                /* non-empty slot has to have child */
                if (!slot->dn->child) {
                        err("%s: slot[%s]'s device_node doesn't have child for adapter\n",
                            __func__, slot->name);
                        return -EINVAL;
                }

                if (list_empty(&bus->devices)) {
                        pseries_eeh_init_edev_recursive(PCI_DN(slot->dn));
                        pci_hp_add_devices(bus);
                }

                if (!list_empty(&bus->devices)) {
                        slot->state = CONFIGURED;
                }

                if (rpaphp_debug) {
                        struct pci_dev *dev;
                        dbg("%s: pci_devs of slot[%pOF]\n", __func__, slot->dn);
                        list_for_each_entry(dev, &bus->devices, bus_list)
                                dbg("\t%s\n", pci_name(dev));
                }
        }

        return 0;
}