// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI Hot Plug Controller Driver for System z
 *
 * Copyright 2012 IBM Corp.
 *
 * Author(s):
 *   Jan Glauber <jang@linux.vnet.ibm.com>
 */

#define pr_fmt(fmt) "zpci: " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/pci_debug.h>
#include <asm/sclp.h>

#define SLOT_NAME_SIZE  10

static int enable_slot(struct hotplug_slot *hotplug_slot)
{
        struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
                                             hotplug_slot);
        int rc;

        mutex_lock(&zdev->state_lock);
        if (zdev->state != ZPCI_FN_STATE_STANDBY) {
                rc = -EIO;
                goto out;
        }

        rc = sclp_pci_configure(zdev->fid);
        zpci_dbg(3, "conf fid:%x, rc:%d\n", zdev->fid, rc);
        if (rc)
                goto out;
        zdev->state = ZPCI_FN_STATE_CONFIGURED;

        rc = zpci_scan_configured_device(zdev, zdev->fh);
out:
        mutex_unlock(&zdev->state_lock);
        return rc;
}

static int disable_slot(struct hotplug_slot *hotplug_slot)
{
        struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
                                             hotplug_slot);
        struct pci_dev *pdev = NULL;
        int rc;

        mutex_lock(&zdev->state_lock);
        if (zdev->state != ZPCI_FN_STATE_CONFIGURED) {
                rc = -EIO;
                goto out;
        }

        pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
        if (pdev && pci_num_vf(pdev)) {
                rc = -EBUSY;
                goto out;
        }

        rc = zpci_deconfigure_device(zdev);
out:
        if (pdev)
                pci_dev_put(pdev);
        mutex_unlock(&zdev->state_lock);
        return rc;
}

static int reset_slot(struct hotplug_slot *hotplug_slot, bool probe)
{
        struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
                                             hotplug_slot);
        int rc = -EIO;

        /*
         * If we can't get the zdev->state_lock the device state is
         * currently undergoing a transition and we bail out - just
         * the same as if the device's state is not configured at all.
         */
        if (!mutex_trylock(&zdev->state_lock))
                return rc;

        /* We can reset only if the function is configured */
        if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
                goto out;

        if (probe) {
                rc = 0;
                goto out;
        }

        rc = zpci_hot_reset_device(zdev);
out:
        mutex_unlock(&zdev->state_lock);
        return rc;
}

static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
        struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
                                             hotplug_slot);

        *value = zpci_is_device_configured(zdev) ? 1 : 0;
        return 0;
}

static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
        /* if the slot exists it always contains a function */
        *value = 1;
        return 0;
}

static const struct hotplug_slot_ops s390_hotplug_slot_ops = {
        .enable_slot =          enable_slot,
        .disable_slot =         disable_slot,
        .reset_slot =           reset_slot,
        .get_power_status =     get_power_status,
        .get_adapter_status =   get_adapter_status,
};

int zpci_init_slot(struct zpci_dev *zdev)
{
        char name[SLOT_NAME_SIZE];
        struct zpci_bus *zbus = zdev->zbus;

        zdev->hotplug_slot.ops = &s390_hotplug_slot_ops;

        snprintf(name, SLOT_NAME_SIZE, "%08x", zdev->fid);
        return pci_hp_register(&zdev->hotplug_slot, zbus->bus,
                               zdev->devfn, name);
}

void zpci_exit_slot(struct zpci_dev *zdev)
{
        pci_hp_deregister(&zdev->hotplug_slot);
}