// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
/* QLogic qedr NIC Driver
 * Copyright (c) 2015-2017  QLogic Corporation
 * Copyright (c) 2019-2020 Marvell International Ltd.
 */

#include <linux/pci.h>
#include <linux/netdevice.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/qed/qede_rdma.h>
#include "qede.h"

static struct qedr_driver *qedr_drv;
static LIST_HEAD(qedr_dev_list);
static DEFINE_MUTEX(qedr_dev_list_lock);

bool qede_rdma_supported(struct qede_dev *dev)
{
        return dev->dev_info.common.rdma_supported;
}

static void _qede_rdma_dev_add(struct qede_dev *edev)
{
        if (!qedr_drv)
                return;

        /* Leftovers from previous error recovery */
        edev->rdma_info.exp_recovery = false;
        edev->rdma_info.qedr_dev = qedr_drv->add(edev->cdev, edev->pdev,
                                                 edev->ndev);
}

static int qede_rdma_create_wq(struct qede_dev *edev)
{
        INIT_LIST_HEAD(&edev->rdma_info.rdma_event_list);
        kref_init(&edev->rdma_info.refcnt);
        init_completion(&edev->rdma_info.event_comp);

        edev->rdma_info.rdma_wq = create_singlethread_workqueue("rdma_wq");
        if (!edev->rdma_info.rdma_wq) {
                DP_NOTICE(edev, "qedr: Could not create workqueue\n");
                return -ENOMEM;
        }

        return 0;
}

static void qede_rdma_cleanup_event(struct qede_dev *edev)
{
        struct list_head *head = &edev->rdma_info.rdma_event_list;
        struct qede_rdma_event_work *event_node;

        flush_workqueue(edev->rdma_info.rdma_wq);
        while (!list_empty(head)) {
                event_node = list_entry(head->next, struct qede_rdma_event_work,
                                        list);
                cancel_work_sync(&event_node->work);
                list_del(&event_node->list);
                kfree(event_node);
        }
}

static void qede_rdma_complete_event(struct kref *ref)
{
        struct qede_rdma_dev *rdma_dev =
                container_of(ref, struct qede_rdma_dev, refcnt);

        /* no more events will be added after this */
        complete(&rdma_dev->event_comp);
}

static void qede_rdma_destroy_wq(struct qede_dev *edev)
{
        /* Avoid race with add_event flow, make sure it finishes before
         * we start accessing the list and cleaning up the work
         */
        kref_put(&edev->rdma_info.refcnt, qede_rdma_complete_event);
        wait_for_completion(&edev->rdma_info.event_comp);

        qede_rdma_cleanup_event(edev);
        destroy_workqueue(edev->rdma_info.rdma_wq);
        edev->rdma_info.rdma_wq = NULL;
}

int qede_rdma_dev_add(struct qede_dev *edev, bool recovery)
{
        int rc;

        if (!qede_rdma_supported(edev))
                return 0;

        /* Cannot start qedr while recovering since it wasn't fully stopped */
        if (recovery)
                return 0;

        rc = qede_rdma_create_wq(edev);
        if (rc)
                return rc;

        INIT_LIST_HEAD(&edev->rdma_info.entry);
        mutex_lock(&qedr_dev_list_lock);
        list_add_tail(&edev->rdma_info.entry, &qedr_dev_list);
        _qede_rdma_dev_add(edev);
        mutex_unlock(&qedr_dev_list_lock);

        return rc;
}

static void _qede_rdma_dev_remove(struct qede_dev *edev)
{
        if (qedr_drv && qedr_drv->remove && edev->rdma_info.qedr_dev)
                qedr_drv->remove(edev->rdma_info.qedr_dev);
}

void qede_rdma_dev_remove(struct qede_dev *edev, bool recovery)
{
        if (!qede_rdma_supported(edev))
                return;

        /* Cannot remove qedr while recovering since it wasn't fully stopped */
        if (!recovery) {
                qede_rdma_destroy_wq(edev);
                mutex_lock(&qedr_dev_list_lock);
                if (!edev->rdma_info.exp_recovery)
                        _qede_rdma_dev_remove(edev);
                edev->rdma_info.qedr_dev = NULL;
                list_del(&edev->rdma_info.entry);
                mutex_unlock(&qedr_dev_list_lock);
        } else {
                if (!edev->rdma_info.exp_recovery) {
                        mutex_lock(&qedr_dev_list_lock);
                        _qede_rdma_dev_remove(edev);
                        mutex_unlock(&qedr_dev_list_lock);
                }
                edev->rdma_info.exp_recovery = true;
        }
}

static void _qede_rdma_dev_open(struct qede_dev *edev)
{
        if (qedr_drv && edev->rdma_info.qedr_dev && qedr_drv->notify)
                qedr_drv->notify(edev->rdma_info.qedr_dev, QEDE_UP);
}

static void qede_rdma_dev_open(struct qede_dev *edev)
{
        if (!qede_rdma_supported(edev))
                return;

        mutex_lock(&qedr_dev_list_lock);
        _qede_rdma_dev_open(edev);
        mutex_unlock(&qedr_dev_list_lock);
}

static void _qede_rdma_dev_close(struct qede_dev *edev)
{
        if (qedr_drv && edev->rdma_info.qedr_dev && qedr_drv->notify)
                qedr_drv->notify(edev->rdma_info.qedr_dev, QEDE_DOWN);
}

static void qede_rdma_dev_close(struct qede_dev *edev)
{
        if (!qede_rdma_supported(edev))
                return;

        mutex_lock(&qedr_dev_list_lock);
        _qede_rdma_dev_close(edev);
        mutex_unlock(&qedr_dev_list_lock);
}

static void qede_rdma_dev_shutdown(struct qede_dev *edev)
{
        if (!qede_rdma_supported(edev))
                return;

        mutex_lock(&qedr_dev_list_lock);
        if (qedr_drv && edev->rdma_info.qedr_dev && qedr_drv->notify)
                qedr_drv->notify(edev->rdma_info.qedr_dev, QEDE_CLOSE);
        mutex_unlock(&qedr_dev_list_lock);
}

int qede_rdma_register_driver(struct qedr_driver *drv)
{
        struct qede_dev *edev;
        u8 qedr_counter = 0;

        mutex_lock(&qedr_dev_list_lock);
        if (qedr_drv) {
                mutex_unlock(&qedr_dev_list_lock);
                return -EINVAL;
        }
        qedr_drv = drv;

        list_for_each_entry(edev, &qedr_dev_list, rdma_info.entry) {
                struct net_device *ndev;

                qedr_counter++;
                _qede_rdma_dev_add(edev);
                ndev = edev->ndev;
                if (netif_running(ndev) && netif_oper_up(ndev))
                        _qede_rdma_dev_open(edev);
        }
        mutex_unlock(&qedr_dev_list_lock);

        pr_notice("qedr: discovered and registered %d RDMA funcs\n",
                  qedr_counter);

        return 0;
}
EXPORT_SYMBOL(qede_rdma_register_driver);

void qede_rdma_unregister_driver(struct qedr_driver *drv)
{
        struct qede_dev *edev;

        mutex_lock(&qedr_dev_list_lock);
        list_for_each_entry(edev, &qedr_dev_list, rdma_info.entry) {
                /* If device has experienced recovery it was already removed */
                if (edev->rdma_info.qedr_dev && !edev->rdma_info.exp_recovery)
                        _qede_rdma_dev_remove(edev);
        }
        qedr_drv = NULL;
        mutex_unlock(&qedr_dev_list_lock);
}
EXPORT_SYMBOL(qede_rdma_unregister_driver);

static void qede_rdma_changeaddr(struct qede_dev *edev)
{
        if (!qede_rdma_supported(edev))
                return;

        if (qedr_drv && edev->rdma_info.qedr_dev && qedr_drv->notify)
                qedr_drv->notify(edev->rdma_info.qedr_dev, QEDE_CHANGE_ADDR);
}

static void qede_rdma_change_mtu(struct qede_dev *edev)
{
        if (qede_rdma_supported(edev)) {
                if (qedr_drv && edev->rdma_info.qedr_dev && qedr_drv->notify)
                        qedr_drv->notify(edev->rdma_info.qedr_dev,
                                         QEDE_CHANGE_MTU);
        }
}

static struct qede_rdma_event_work *
qede_rdma_get_free_event_node(struct qede_dev *edev)
{
        struct qede_rdma_event_work *event_node = NULL;
        bool found = false;

        list_for_each_entry(event_node, &edev->rdma_info.rdma_event_list,
                            list) {
                if (!work_pending(&event_node->work)) {
                        found = true;
                        break;
                }
        }

        if (!found) {
                event_node = kzalloc_obj(*event_node, GFP_ATOMIC);
                if (!event_node) {
                        DP_NOTICE(edev,
                                  "qedr: Could not allocate memory for rdma work\n");
                        return NULL;
                }
                list_add_tail(&event_node->list,
                              &edev->rdma_info.rdma_event_list);
        }

        return event_node;
}

static void qede_rdma_handle_event(struct work_struct *work)
{
        struct qede_rdma_event_work *event_node;
        enum qede_rdma_event event;
        struct qede_dev *edev;

        event_node = container_of(work, struct qede_rdma_event_work, work);
        event = event_node->event;
        edev = event_node->ptr;

        switch (event) {
        case QEDE_UP:
                qede_rdma_dev_open(edev);
                break;
        case QEDE_DOWN:
                qede_rdma_dev_close(edev);
                break;
        case QEDE_CLOSE:
                qede_rdma_dev_shutdown(edev);
                break;
        case QEDE_CHANGE_ADDR:
                qede_rdma_changeaddr(edev);
                break;
        case QEDE_CHANGE_MTU:
                qede_rdma_change_mtu(edev);
                break;
        default:
                DP_NOTICE(edev, "Invalid rdma event %d", event);
        }
}

static void qede_rdma_add_event(struct qede_dev *edev,
                                enum qede_rdma_event event)
{
        struct qede_rdma_event_work *event_node;

        /* If a recovery was experienced avoid adding the event */
        if (edev->rdma_info.exp_recovery)
                return;

        if (!edev->rdma_info.qedr_dev || !edev->rdma_info.rdma_wq)
                return;

        /* We don't want the cleanup flow to start while we're allocating and
         * scheduling the work
         */
        if (!kref_get_unless_zero(&edev->rdma_info.refcnt))
                return; /* already being destroyed */

        event_node = qede_rdma_get_free_event_node(edev);
        if (!event_node)
                goto out;

        event_node->event = event;
        event_node->ptr = edev;

        INIT_WORK(&event_node->work, qede_rdma_handle_event);
        queue_work(edev->rdma_info.rdma_wq, &event_node->work);

out:
        kref_put(&edev->rdma_info.refcnt, qede_rdma_complete_event);
}

void qede_rdma_dev_event_open(struct qede_dev *edev)
{
        qede_rdma_add_event(edev, QEDE_UP);
}

void qede_rdma_dev_event_close(struct qede_dev *edev)
{
        qede_rdma_add_event(edev, QEDE_DOWN);
}

void qede_rdma_event_changeaddr(struct qede_dev *edev)
{
        qede_rdma_add_event(edev, QEDE_CHANGE_ADDR);
}

void qede_rdma_event_change_mtu(struct qede_dev *edev)
{
        qede_rdma_add_event(edev, QEDE_CHANGE_MTU);
}