/*
 * Copyright (c) 2012 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <rdma/ib_mad.h>

#include <linux/mlx4/cmd.h>
#include <linux/rbtree.h>
#include <linux/idr.h>
#include <rdma/ib_cm.h>

#include "mlx4_ib.h"

#define CM_CLEANUP_CACHE_TIMEOUT  (30 * HZ)

struct id_map_entry {
        struct rb_node node;

        u32 sl_cm_id;
        u32 pv_cm_id;
        int slave_id;
        int scheduled_delete;
        struct mlx4_ib_dev *dev;

        struct list_head list;
        struct delayed_work timeout;
};

struct rej_tmout_entry {
        int slave;
        u32 rem_pv_cm_id;
        struct delayed_work timeout;
        struct xarray *xa_rej_tmout;
};

struct cm_generic_msg {
        struct ib_mad_hdr hdr;

        __be32 local_comm_id;
        __be32 remote_comm_id;
        unsigned char unused[2];
        __be16 rej_reason;
};

struct cm_sidr_generic_msg {
        struct ib_mad_hdr hdr;
        __be32 request_id;
};

struct cm_req_msg {
        unsigned char unused[0x60];
        union ib_gid primary_path_sgid;
};


static void set_local_comm_id(struct ib_mad *mad, u32 cm_id)
{
        if (mad->mad_hdr.attr_id == CM_SIDR_REQ_ATTR_ID) {
                struct cm_sidr_generic_msg *msg =
                        (struct cm_sidr_generic_msg *)mad;
                msg->request_id = cpu_to_be32(cm_id);
        } else if (mad->mad_hdr.attr_id == CM_SIDR_REP_ATTR_ID) {
                pr_err("trying to set local_comm_id in SIDR_REP\n");
                return;
        } else {
                struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;
                msg->local_comm_id = cpu_to_be32(cm_id);
        }
}

static u32 get_local_comm_id(struct ib_mad *mad)
{
        if (mad->mad_hdr.attr_id == CM_SIDR_REQ_ATTR_ID) {
                struct cm_sidr_generic_msg *msg =
                        (struct cm_sidr_generic_msg *)mad;
                return be32_to_cpu(msg->request_id);
        } else if (mad->mad_hdr.attr_id == CM_SIDR_REP_ATTR_ID) {
                pr_err("trying to set local_comm_id in SIDR_REP\n");
                return -1;
        } else {
                struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;
                return be32_to_cpu(msg->local_comm_id);
        }
}

static void set_remote_comm_id(struct ib_mad *mad, u32 cm_id)
{
        if (mad->mad_hdr.attr_id == CM_SIDR_REP_ATTR_ID) {
                struct cm_sidr_generic_msg *msg =
                        (struct cm_sidr_generic_msg *)mad;
                msg->request_id = cpu_to_be32(cm_id);
        } else if (mad->mad_hdr.attr_id == CM_SIDR_REQ_ATTR_ID) {
                pr_err("trying to set remote_comm_id in SIDR_REQ\n");
                return;
        } else {
                struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;
                msg->remote_comm_id = cpu_to_be32(cm_id);
        }
}

static u32 get_remote_comm_id(struct ib_mad *mad)
{
        if (mad->mad_hdr.attr_id == CM_SIDR_REP_ATTR_ID) {
                struct cm_sidr_generic_msg *msg =
                        (struct cm_sidr_generic_msg *)mad;
                return be32_to_cpu(msg->request_id);
        } else if (mad->mad_hdr.attr_id == CM_SIDR_REQ_ATTR_ID) {
                pr_err("trying to set remote_comm_id in SIDR_REQ\n");
                return -1;
        } else {
                struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;
                return be32_to_cpu(msg->remote_comm_id);
        }
}

static union ib_gid gid_from_req_msg(struct ib_device *ibdev, struct ib_mad *mad)
{
        struct cm_req_msg *msg = (struct cm_req_msg *)mad;

        return msg->primary_path_sgid;
}

/* Lock should be taken before called */
static struct id_map_entry *
id_map_find_by_sl_id(struct ib_device *ibdev, u32 slave_id, u32 sl_cm_id)
{
        struct rb_root *sl_id_map = &to_mdev(ibdev)->sriov.sl_id_map;
        struct rb_node *node = sl_id_map->rb_node;

        while (node) {
                struct id_map_entry *id_map_entry =
                        rb_entry(node, struct id_map_entry, node);

                if (id_map_entry->sl_cm_id > sl_cm_id)
                        node = node->rb_left;
                else if (id_map_entry->sl_cm_id < sl_cm_id)
                        node = node->rb_right;
                else if (id_map_entry->slave_id > slave_id)
                        node = node->rb_left;
                else if (id_map_entry->slave_id < slave_id)
                        node = node->rb_right;
                else
                        return id_map_entry;
        }
        return NULL;
}

static void id_map_ent_timeout(struct work_struct *work)
{
        struct delayed_work *delay = to_delayed_work(work);
        struct id_map_entry *ent = container_of(delay, struct id_map_entry, timeout);
        struct id_map_entry *found_ent;
        struct mlx4_ib_dev *dev = ent->dev;
        struct mlx4_ib_sriov *sriov = &dev->sriov;
        struct rb_root *sl_id_map = &sriov->sl_id_map;

        spin_lock(&sriov->id_map_lock);
        if (!xa_erase(&sriov->pv_id_table, ent->pv_cm_id))
                goto out;
        found_ent = id_map_find_by_sl_id(&dev->ib_dev, ent->slave_id, ent->sl_cm_id);
        if (found_ent && found_ent == ent)
                rb_erase(&found_ent->node, sl_id_map);

out:
        list_del(&ent->list);
        spin_unlock(&sriov->id_map_lock);
        kfree(ent);
}

static void sl_id_map_add(struct ib_device *ibdev, struct id_map_entry *new)
{
        struct rb_root *sl_id_map = &to_mdev(ibdev)->sriov.sl_id_map;
        struct rb_node **link = &sl_id_map->rb_node, *parent = NULL;
        struct id_map_entry *ent;
        int slave_id = new->slave_id;
        int sl_cm_id = new->sl_cm_id;

        ent = id_map_find_by_sl_id(ibdev, slave_id, sl_cm_id);
        if (ent) {
                pr_debug("overriding existing sl_id_map entry (cm_id = %x)\n",
                         sl_cm_id);

                rb_replace_node(&ent->node, &new->node, sl_id_map);
                return;
        }

        /* Go to the bottom of the tree */
        while (*link) {
                parent = *link;
                ent = rb_entry(parent, struct id_map_entry, node);

                if (ent->sl_cm_id > sl_cm_id || (ent->sl_cm_id == sl_cm_id && ent->slave_id > slave_id))
                        link = &(*link)->rb_left;
                else
                        link = &(*link)->rb_right;
        }

        rb_link_node(&new->node, parent, link);
        rb_insert_color(&new->node, sl_id_map);
}

static struct id_map_entry *
id_map_alloc(struct ib_device *ibdev, int slave_id, u32 sl_cm_id)
{
        int ret;
        struct id_map_entry *ent;
        struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;

        ent = kmalloc(sizeof (struct id_map_entry), GFP_KERNEL);
        if (!ent)
                return ERR_PTR(-ENOMEM);

        ent->sl_cm_id = sl_cm_id;
        ent->slave_id = slave_id;
        ent->scheduled_delete = 0;
        ent->dev = to_mdev(ibdev);
        INIT_DELAYED_WORK(&ent->timeout, id_map_ent_timeout);

        ret = xa_alloc_cyclic(&sriov->pv_id_table, &ent->pv_cm_id, ent,
                        xa_limit_32b, &sriov->pv_id_next, GFP_KERNEL);
        if (ret >= 0) {
                spin_lock(&sriov->id_map_lock);
                sl_id_map_add(ibdev, ent);
                list_add_tail(&ent->list, &sriov->cm_list);
                spin_unlock(&sriov->id_map_lock);
                return ent;
        }

        /*error flow*/
        kfree(ent);
        mlx4_ib_warn(ibdev, "Allocation failed (err:0x%x)\n", ret);
        return ERR_PTR(-ENOMEM);
}

static struct id_map_entry *
id_map_get(struct ib_device *ibdev, int *pv_cm_id, int slave_id, int sl_cm_id)
{
        struct id_map_entry *ent;
        struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;

        spin_lock(&sriov->id_map_lock);
        if (*pv_cm_id == -1) {
                ent = id_map_find_by_sl_id(ibdev, slave_id, sl_cm_id);
                if (ent)
                        *pv_cm_id = (int) ent->pv_cm_id;
        } else
                ent = xa_load(&sriov->pv_id_table, *pv_cm_id);
        spin_unlock(&sriov->id_map_lock);

        return ent;
}

static void schedule_delayed(struct ib_device *ibdev, struct id_map_entry *id)
{
        struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;
        unsigned long flags;

        spin_lock(&sriov->id_map_lock);
        spin_lock_irqsave(&sriov->going_down_lock, flags);
        /*make sure that there is no schedule inside the scheduled work.*/
        if (!sriov->is_going_down && !id->scheduled_delete) {
                id->scheduled_delete = 1;
                schedule_delayed_work(&id->timeout, CM_CLEANUP_CACHE_TIMEOUT);
        } else if (id->scheduled_delete) {
                /* Adjust timeout if already scheduled */
                mod_delayed_work(system_wq, &id->timeout, CM_CLEANUP_CACHE_TIMEOUT);
        }
        spin_unlock_irqrestore(&sriov->going_down_lock, flags);
        spin_unlock(&sriov->id_map_lock);
}

#define REJ_REASON(m) be16_to_cpu(((struct cm_generic_msg *)(m))->rej_reason)
int mlx4_ib_multiplex_cm_handler(struct ib_device *ibdev, int port, int slave_id,
                struct ib_mad *mad)
{
        struct id_map_entry *id;
        u32 sl_cm_id;
        int pv_cm_id = -1;

        if (mad->mad_hdr.attr_id == CM_REQ_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_REP_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_MRA_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_SIDR_REQ_ATTR_ID ||
            (mad->mad_hdr.attr_id == CM_REJ_ATTR_ID && REJ_REASON(mad) == IB_CM_REJ_TIMEOUT)) {
                sl_cm_id = get_local_comm_id(mad);
                id = id_map_get(ibdev, &pv_cm_id, slave_id, sl_cm_id);
                if (id)
                        goto cont;
                id = id_map_alloc(ibdev, slave_id, sl_cm_id);
                if (IS_ERR(id)) {
                        mlx4_ib_warn(ibdev, "%s: id{slave: %d, sl_cm_id: 0x%x} Failed to id_map_alloc\n",
                                __func__, slave_id, sl_cm_id);
                        return PTR_ERR(id);
                }
        } else if (mad->mad_hdr.attr_id == CM_REJ_ATTR_ID ||
                   mad->mad_hdr.attr_id == CM_SIDR_REP_ATTR_ID) {
                return 0;
        } else {
                sl_cm_id = get_local_comm_id(mad);
                id = id_map_get(ibdev, &pv_cm_id, slave_id, sl_cm_id);
        }

        if (!id) {
                pr_debug("id{slave: %d, sl_cm_id: 0x%x} is NULL! attr_id: 0x%x\n",
                         slave_id, sl_cm_id, be16_to_cpu(mad->mad_hdr.attr_id));
                return -EINVAL;
        }

cont:
        set_local_comm_id(mad, id->pv_cm_id);

        if (mad->mad_hdr.attr_id == CM_DREQ_ATTR_ID)
                schedule_delayed(ibdev, id);
        return 0;
}

static void rej_tmout_timeout(struct work_struct *work)
{
        struct delayed_work *delay = to_delayed_work(work);
        struct rej_tmout_entry *item = container_of(delay, struct rej_tmout_entry, timeout);
        struct rej_tmout_entry *deleted;

        deleted = xa_cmpxchg(item->xa_rej_tmout, item->rem_pv_cm_id, item, NULL, 0);

        if (deleted != item)
                pr_debug("deleted(%p) != item(%p)\n", deleted, item);

        kfree(item);
}

static int alloc_rej_tmout(struct mlx4_ib_sriov *sriov, u32 rem_pv_cm_id, int slave)
{
        struct rej_tmout_entry *item;
        struct rej_tmout_entry *old;
        int ret = 0;

        xa_lock(&sriov->xa_rej_tmout);
        item = xa_load(&sriov->xa_rej_tmout, (unsigned long)rem_pv_cm_id);

        if (item) {
                if (xa_err(item))
                        ret =  xa_err(item);
                else
                        /* If a retry, adjust delayed work */
                        mod_delayed_work(system_wq, &item->timeout, CM_CLEANUP_CACHE_TIMEOUT);
                goto err_or_exists;
        }
        xa_unlock(&sriov->xa_rej_tmout);

        item = kmalloc(sizeof(*item), GFP_KERNEL);
        if (!item)
                return -ENOMEM;

        INIT_DELAYED_WORK(&item->timeout, rej_tmout_timeout);
        item->slave = slave;
        item->rem_pv_cm_id = rem_pv_cm_id;
        item->xa_rej_tmout = &sriov->xa_rej_tmout;

        old = xa_cmpxchg(&sriov->xa_rej_tmout, (unsigned long)rem_pv_cm_id, NULL, item, GFP_KERNEL);
        if (old) {
                pr_debug(
                        "Non-null old entry (%p) or error (%d) when inserting\n",
                        old, xa_err(old));
                kfree(item);
                return xa_err(old);
        }

        schedule_delayed_work(&item->timeout, CM_CLEANUP_CACHE_TIMEOUT);

        return 0;

err_or_exists:
        xa_unlock(&sriov->xa_rej_tmout);
        return ret;
}

static int lookup_rej_tmout_slave(struct mlx4_ib_sriov *sriov, u32 rem_pv_cm_id)
{
        struct rej_tmout_entry *item;
        int slave;

        xa_lock(&sriov->xa_rej_tmout);
        item = xa_load(&sriov->xa_rej_tmout, (unsigned long)rem_pv_cm_id);

        if (!item || xa_err(item)) {
                pr_debug("Could not find slave. rem_pv_cm_id 0x%x error: %d\n",
                         rem_pv_cm_id, xa_err(item));
                slave = !item ? -ENOENT : xa_err(item);
        } else {
                slave = item->slave;
        }
        xa_unlock(&sriov->xa_rej_tmout);

        return slave;
}

int mlx4_ib_demux_cm_handler(struct ib_device *ibdev, int port, int *slave,
                             struct ib_mad *mad)
{
        struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;
        u32 rem_pv_cm_id = get_local_comm_id(mad);
        u32 pv_cm_id;
        struct id_map_entry *id;
        int sts;

        if (mad->mad_hdr.attr_id == CM_REQ_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_SIDR_REQ_ATTR_ID) {
                union ib_gid gid;

                if (!slave)
                        return 0;

                gid = gid_from_req_msg(ibdev, mad);
                *slave = mlx4_ib_find_real_gid(ibdev, port, gid.global.interface_id);
                if (*slave < 0) {
                        mlx4_ib_warn(ibdev, "failed matching slave_id by gid (0x%llx)\n",
                                     be64_to_cpu(gid.global.interface_id));
                        return -ENOENT;
                }

                sts = alloc_rej_tmout(sriov, rem_pv_cm_id, *slave);
                if (sts)
                        /* Even if this fails, we pass on the REQ to the slave */
                        pr_debug("Could not allocate rej_tmout entry. rem_pv_cm_id 0x%x slave %d status %d\n",
                                 rem_pv_cm_id, *slave, sts);

                return 0;
        }

        pv_cm_id = get_remote_comm_id(mad);
        id = id_map_get(ibdev, (int *)&pv_cm_id, -1, -1);

        if (!id) {
                if (mad->mad_hdr.attr_id == CM_REJ_ATTR_ID &&
                    REJ_REASON(mad) == IB_CM_REJ_TIMEOUT && slave) {
                        *slave = lookup_rej_tmout_slave(sriov, rem_pv_cm_id);

                        return (*slave < 0) ? *slave : 0;
                }
                pr_debug("Couldn't find an entry for pv_cm_id 0x%x, attr_id 0x%x\n",
                         pv_cm_id, be16_to_cpu(mad->mad_hdr.attr_id));
                return -ENOENT;
        }

        if (slave)
                *slave = id->slave_id;
        set_remote_comm_id(mad, id->sl_cm_id);

        if (mad->mad_hdr.attr_id == CM_DREQ_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_REJ_ATTR_ID)
                schedule_delayed(ibdev, id);

        return 0;
}

void mlx4_ib_cm_paravirt_init(struct mlx4_ib_dev *dev)
{
        spin_lock_init(&dev->sriov.id_map_lock);
        INIT_LIST_HEAD(&dev->sriov.cm_list);
        dev->sriov.sl_id_map = RB_ROOT;
        xa_init_flags(&dev->sriov.pv_id_table, XA_FLAGS_ALLOC);
        xa_init(&dev->sriov.xa_rej_tmout);
}

static void rej_tmout_xa_cleanup(struct mlx4_ib_sriov *sriov, int slave)
{
        struct rej_tmout_entry *item;
        bool flush_needed = false;
        unsigned long id;
        int cnt = 0;

        xa_lock(&sriov->xa_rej_tmout);
        xa_for_each(&sriov->xa_rej_tmout, id, item) {
                if (slave < 0 || slave == item->slave) {
                        mod_delayed_work(system_wq, &item->timeout, 0);
                        flush_needed = true;
                        ++cnt;
                }
        }
        xa_unlock(&sriov->xa_rej_tmout);

        if (flush_needed) {
                flush_scheduled_work();
                pr_debug("Deleted %d entries in xarray for slave %d during cleanup\n",
                         cnt, slave);
        }

        if (slave < 0)
                WARN_ON(!xa_empty(&sriov->xa_rej_tmout));
}

/* slave = -1 ==> all slaves */
/* TBD -- call paravirt clean for single slave.  Need for slave RESET event */
void mlx4_ib_cm_paravirt_clean(struct mlx4_ib_dev *dev, int slave)
{
        struct mlx4_ib_sriov *sriov = &dev->sriov;
        struct rb_root *sl_id_map = &sriov->sl_id_map;
        struct list_head lh;
        struct rb_node *nd;
        int need_flush = 0;
        struct id_map_entry *map, *tmp_map;
        /* cancel all delayed work queue entries */
        INIT_LIST_HEAD(&lh);
        spin_lock(&sriov->id_map_lock);
        list_for_each_entry_safe(map, tmp_map, &dev->sriov.cm_list, list) {
                if (slave < 0 || slave == map->slave_id) {
                        if (map->scheduled_delete)
                                need_flush |= !cancel_delayed_work(&map->timeout);
                }
        }

        spin_unlock(&sriov->id_map_lock);

        if (need_flush)
                flush_scheduled_work(); /* make sure all timers were flushed */

        /* now, remove all leftover entries from databases*/
        spin_lock(&sriov->id_map_lock);
        if (slave < 0) {
                while (rb_first(sl_id_map)) {
                        struct id_map_entry *ent =
                                rb_entry(rb_first(sl_id_map),
                                         struct id_map_entry, node);

                        rb_erase(&ent->node, sl_id_map);
                        xa_erase(&sriov->pv_id_table, ent->pv_cm_id);
                }
                list_splice_init(&dev->sriov.cm_list, &lh);
        } else {
                /* first, move nodes belonging to slave to db remove list */
                nd = rb_first(sl_id_map);
                while (nd) {
                        struct id_map_entry *ent =
                                rb_entry(nd, struct id_map_entry, node);
                        nd = rb_next(nd);
                        if (ent->slave_id == slave)
                                list_move_tail(&ent->list, &lh);
                }
                /* remove those nodes from databases */
                list_for_each_entry_safe(map, tmp_map, &lh, list) {
                        rb_erase(&map->node, sl_id_map);
                        xa_erase(&sriov->pv_id_table, map->pv_cm_id);
                }

                /* add remaining nodes from cm_list */
                list_for_each_entry_safe(map, tmp_map, &dev->sriov.cm_list, list) {
                        if (slave == map->slave_id)
                                list_move_tail(&map->list, &lh);
                }
        }

        spin_unlock(&sriov->id_map_lock);

        /* free any map entries left behind due to cancel_delayed_work above */
        list_for_each_entry_safe(map, tmp_map, &lh, list) {
                list_del(&map->list);
                kfree(map);
        }

        rej_tmout_xa_cleanup(sriov, slave);
}