// SPDX-License-Identifier: GPL-2.0
/*
 * zfcp device driver
 *
 * Registration and callback for the s390 common I/O layer.
 *
 * Copyright IBM Corp. 2002, 2010
 */

#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include "zfcp_ext.h"
#include "zfcp_reqlist.h"

#define ZFCP_MODEL_PRIV 0x4

static DEFINE_SPINLOCK(zfcp_ccw_adapter_ref_lock);

struct zfcp_adapter *zfcp_ccw_adapter_by_cdev(struct ccw_device *cdev)
{
        struct zfcp_adapter *adapter;
        unsigned long flags;

        spin_lock_irqsave(&zfcp_ccw_adapter_ref_lock, flags);
        adapter = dev_get_drvdata(&cdev->dev);
        if (adapter)
                kref_get(&adapter->ref);
        spin_unlock_irqrestore(&zfcp_ccw_adapter_ref_lock, flags);
        return adapter;
}

void zfcp_ccw_adapter_put(struct zfcp_adapter *adapter)
{
        unsigned long flags;

        spin_lock_irqsave(&zfcp_ccw_adapter_ref_lock, flags);
        kref_put(&adapter->ref, zfcp_adapter_release);
        spin_unlock_irqrestore(&zfcp_ccw_adapter_ref_lock, flags);
}

/**
 * zfcp_ccw_activate - activate adapter and wait for it to finish
 * @cdev: pointer to belonging ccw device
 * @clear: Status flags to clear.
 * @tag: s390dbf trace record tag
 */
static int zfcp_ccw_activate(struct ccw_device *cdev, int clear, char *tag)
{
        struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);

        if (!adapter)
                return 0;

        zfcp_erp_clear_adapter_status(adapter, clear);
        zfcp_erp_set_adapter_status(adapter, ZFCP_STATUS_COMMON_RUNNING);
        zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
                                tag);

        /*
         * We want to scan ports here, with some random backoff and without
         * rate limit. Recovery has already scheduled a port scan for us,
         * but with both random delay and rate limit. Nevertheless we get
         * what we want here by flushing the scheduled work after sleeping
         * an equivalent random time.
         * Let the port scan random delay elapse first. If recovery finishes
         * up to that point in time, that would be perfect for both recovery
         * and port scan. If not, i.e. recovery takes ages, there was no
         * point in waiting a random delay on top of the time consumed by
         * recovery.
         */
        msleep(zfcp_fc_port_scan_backoff());
        zfcp_erp_wait(adapter);
        flush_delayed_work(&adapter->scan_work);

        zfcp_ccw_adapter_put(adapter);

        return 0;
}

static struct ccw_device_id zfcp_ccw_device_id[] = {
        { CCW_DEVICE_DEVTYPE(0x1731, 0x3, 0x1732, 0x3) },
        { CCW_DEVICE_DEVTYPE(0x1731, 0x3, 0x1732, ZFCP_MODEL_PRIV) },
        {},
};
MODULE_DEVICE_TABLE(ccw, zfcp_ccw_device_id);

/**
 * zfcp_ccw_probe - probe function of zfcp driver
 * @cdev: pointer to belonging ccw device
 *
 * This function gets called by the common i/o layer for each FCP
 * device found on the current system. This is only a stub to make cio
 * work: To only allocate adapter resources for devices actually used,
 * the allocation is deferred to the first call to ccw_set_online.
 */
static int zfcp_ccw_probe(struct ccw_device *cdev)
{
        return 0;
}

/**
 * zfcp_ccw_remove - remove function of zfcp driver
 * @cdev: pointer to belonging ccw device
 *
 * This function gets called by the common i/o layer and removes an adapter
 * from the system. Task of this function is to get rid of all units and
 * ports that belong to this adapter. And in addition all resources of this
 * adapter will be freed too.
 */
static void zfcp_ccw_remove(struct ccw_device *cdev)
{
        struct zfcp_adapter *adapter;
        struct zfcp_port *port, *p;
        struct zfcp_unit *unit, *u;
        LIST_HEAD(unit_remove_lh);
        LIST_HEAD(port_remove_lh);

        ccw_device_set_offline(cdev);

        adapter = zfcp_ccw_adapter_by_cdev(cdev);
        if (!adapter)
                return;

        write_lock_irq(&adapter->port_list_lock);
        list_for_each_entry(port, &adapter->port_list, list) {
                write_lock(&port->unit_list_lock);
                list_splice_init(&port->unit_list, &unit_remove_lh);
                write_unlock(&port->unit_list_lock);
        }
        list_splice_init(&adapter->port_list, &port_remove_lh);
        write_unlock_irq(&adapter->port_list_lock);
        zfcp_ccw_adapter_put(adapter); /* put from zfcp_ccw_adapter_by_cdev */

        list_for_each_entry_safe(unit, u, &unit_remove_lh, list)
                device_unregister(&unit->dev);

        list_for_each_entry_safe(port, p, &port_remove_lh, list)
                device_unregister(&port->dev);

        zfcp_adapter_unregister(adapter);
}

/**
 * zfcp_ccw_set_online - set_online function of zfcp driver
 * @cdev: pointer to belonging ccw device
 *
 * This function gets called by the common i/o layer and sets an
 * adapter into state online.  The first call will allocate all
 * adapter resources that will be retained until the device is removed
 * via zfcp_ccw_remove.
 *
 * Setting an fcp device online means that it will be registered with
 * the SCSI stack, that the QDIO queues will be set up and that the
 * adapter will be opened.
 */
static int zfcp_ccw_set_online(struct ccw_device *cdev)
{
        struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);

        if (!adapter) {
                adapter = zfcp_adapter_enqueue(cdev);

                if (IS_ERR(adapter)) {
                        dev_err(&cdev->dev,
                                "Setting up data structures for the "
                                "FCP adapter failed\n");
                        return PTR_ERR(adapter);
                }
                kref_get(&adapter->ref);
        }

        /* initialize request counter */
        BUG_ON(!zfcp_reqlist_isempty(adapter->req_list));
        adapter->req_no = 0;

        zfcp_ccw_activate(cdev, 0, "ccsonl1");

        /*
         * We want to scan ports here, always, with some random delay and
         * without rate limit - basically what zfcp_ccw_activate() has
         * achieved for us. Not quite! That port scan depended on
         * !no_auto_port_rescan. So let's cover the no_auto_port_rescan
         * case here to make sure a port scan is done unconditionally.
         * Since zfcp_ccw_activate() has waited the desired random time,
         * we can immediately schedule and flush a port scan for the
         * remaining cases.
         */
        zfcp_fc_inverse_conditional_port_scan(adapter);
        flush_delayed_work(&adapter->scan_work);
        zfcp_ccw_adapter_put(adapter);
        return 0;
}

/**
 * zfcp_ccw_set_offline - set_offline function of zfcp driver
 * @cdev: pointer to belonging ccw device
 *
 * This function gets called by the common i/o layer and sets an adapter
 * into state offline.
 */
static int zfcp_ccw_set_offline(struct ccw_device *cdev)
{
        struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);

        if (!adapter)
                return 0;

        zfcp_erp_set_adapter_status(adapter, 0);
        zfcp_erp_adapter_shutdown(adapter, 0, "ccsoff1");
        zfcp_erp_wait(adapter);

        zfcp_ccw_adapter_put(adapter);
        return 0;
}

/**
 * zfcp_ccw_notify - ccw notify function
 * @cdev: pointer to belonging ccw device
 * @event: indicates if adapter was detached or attached
 *
 * This function gets called by the common i/o layer if an adapter has gone
 * or reappeared.
 */
static int zfcp_ccw_notify(struct ccw_device *cdev, int event)
{
        struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);

        if (!adapter)
                return 1;

        switch (event) {
        case CIO_GONE:
                dev_warn(&cdev->dev, "The FCP device has been detached\n");
                zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti1");
                break;
        case CIO_NO_PATH:
                dev_warn(&cdev->dev,
                         "The CHPID for the FCP device is offline\n");
                zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti2");
                break;
        case CIO_OPER:
                dev_info(&cdev->dev, "The FCP device is operational again\n");
                zfcp_erp_set_adapter_status(adapter,
                                            ZFCP_STATUS_COMMON_RUNNING);
                zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
                                        "ccnoti4");
                break;
        case CIO_BOXED:
                dev_warn(&cdev->dev, "The FCP device did not respond within "
                                     "the specified time\n");
                zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti5");
                break;
        }

        zfcp_ccw_adapter_put(adapter);
        return 1;
}

/**
 * zfcp_ccw_shutdown - handle shutdown from cio
 * @cdev: device for adapter to shutdown.
 */
static void zfcp_ccw_shutdown(struct ccw_device *cdev)
{
        struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);

        if (!adapter)
                return;

        zfcp_erp_adapter_shutdown(adapter, 0, "ccshut1");
        zfcp_erp_wait(adapter);
        zfcp_erp_thread_kill(adapter);

        zfcp_ccw_adapter_put(adapter);
}

struct ccw_driver zfcp_ccw_driver = {
        .driver = {
                .owner  = THIS_MODULE,
                .name   = "zfcp",
        },
        .ids         = zfcp_ccw_device_id,
        .probe       = zfcp_ccw_probe,
        .remove      = zfcp_ccw_remove,
        .set_online  = zfcp_ccw_set_online,
        .set_offline = zfcp_ccw_set_offline,
        .notify      = zfcp_ccw_notify,
        .shutdown    = zfcp_ccw_shutdown,
};