/*
 * Copyright (c) 2006 Oracle.  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 <linux/kernel.h>
#include <linux/in.h>
#include <linux/if.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_arp.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>

#include "rds.h"
#include "iw.h"

unsigned int fastreg_pool_size = RDS_FASTREG_POOL_SIZE;
unsigned int fastreg_message_size = RDS_FASTREG_SIZE + 1; /* +1 allows for unaligned MRs */

module_param(fastreg_pool_size, int, 0444);
MODULE_PARM_DESC(fastreg_pool_size, " Max number of fastreg MRs per device");
module_param(fastreg_message_size, int, 0444);
MODULE_PARM_DESC(fastreg_message_size, " Max size of a RDMA transfer (fastreg MRs)");

struct list_head rds_iw_devices;

/* NOTE: if also grabbing iwdev lock, grab this first */
DEFINE_SPINLOCK(iw_nodev_conns_lock);
LIST_HEAD(iw_nodev_conns);

static void rds_iw_add_one(struct ib_device *device)
{
        struct rds_iw_device *rds_iwdev;
        struct ib_device_attr *dev_attr;

        /* Only handle iwarp devices */
        if (device->node_type != RDMA_NODE_RNIC)
                return;

        dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
        if (!dev_attr)
                return;

        if (ib_query_device(device, dev_attr)) {
                rdsdebug("Query device failed for %s\n", device->name);
                goto free_attr;
        }

        rds_iwdev = kmalloc(sizeof *rds_iwdev, GFP_KERNEL);
        if (!rds_iwdev)
                goto free_attr;

        spin_lock_init(&rds_iwdev->spinlock);

        rds_iwdev->dma_local_lkey = !!(dev_attr->device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY);
        rds_iwdev->max_wrs = dev_attr->max_qp_wr;
        rds_iwdev->max_sge = min(dev_attr->max_sge, RDS_IW_MAX_SGE);

        rds_iwdev->dev = device;
        rds_iwdev->pd = ib_alloc_pd(device);
        if (IS_ERR(rds_iwdev->pd))
                goto free_dev;

        if (!rds_iwdev->dma_local_lkey) {
                rds_iwdev->mr = ib_get_dma_mr(rds_iwdev->pd,
                                        IB_ACCESS_REMOTE_READ |
                                        IB_ACCESS_REMOTE_WRITE |
                                        IB_ACCESS_LOCAL_WRITE);
                if (IS_ERR(rds_iwdev->mr))
                        goto err_pd;
        } else
                rds_iwdev->mr = NULL;

        rds_iwdev->mr_pool = rds_iw_create_mr_pool(rds_iwdev);
        if (IS_ERR(rds_iwdev->mr_pool)) {
                rds_iwdev->mr_pool = NULL;
                goto err_mr;
        }

        INIT_LIST_HEAD(&rds_iwdev->cm_id_list);
        INIT_LIST_HEAD(&rds_iwdev->conn_list);
        list_add_tail(&rds_iwdev->list, &rds_iw_devices);

        ib_set_client_data(device, &rds_iw_client, rds_iwdev);

        goto free_attr;

err_mr:
        if (rds_iwdev->mr)
                ib_dereg_mr(rds_iwdev->mr);
err_pd:
        ib_dealloc_pd(rds_iwdev->pd);
free_dev:
        kfree(rds_iwdev);
free_attr:
        kfree(dev_attr);
}

static void rds_iw_remove_one(struct ib_device *device)
{
        struct rds_iw_device *rds_iwdev;
        struct rds_iw_cm_id *i_cm_id, *next;

        rds_iwdev = ib_get_client_data(device, &rds_iw_client);
        if (!rds_iwdev)
                return;

        spin_lock_irq(&rds_iwdev->spinlock);
        list_for_each_entry_safe(i_cm_id, next, &rds_iwdev->cm_id_list, list) {
                list_del(&i_cm_id->list);
                kfree(i_cm_id);
        }
        spin_unlock_irq(&rds_iwdev->spinlock);

        rds_iw_destroy_conns(rds_iwdev);

        if (rds_iwdev->mr_pool)
                rds_iw_destroy_mr_pool(rds_iwdev->mr_pool);

        if (rds_iwdev->mr)
                ib_dereg_mr(rds_iwdev->mr);

        while (ib_dealloc_pd(rds_iwdev->pd)) {
                rdsdebug("Failed to dealloc pd %p\n", rds_iwdev->pd);
                msleep(1);
        }

        list_del(&rds_iwdev->list);
        kfree(rds_iwdev);
}

struct ib_client rds_iw_client = {
        .name   = "rds_iw",
        .add    = rds_iw_add_one,
        .remove = rds_iw_remove_one
};

static int rds_iw_conn_info_visitor(struct rds_connection *conn,
                                    void *buffer)
{
        struct rds_info_rdma_connection *iinfo = buffer;
        struct rds_iw_connection *ic;

        /* We will only ever look at IB transports */
        if (conn->c_trans != &rds_iw_transport)
                return 0;

        iinfo->src_addr = conn->c_laddr;
        iinfo->dst_addr = conn->c_faddr;

        memset(&iinfo->src_gid, 0, sizeof(iinfo->src_gid));
        memset(&iinfo->dst_gid, 0, sizeof(iinfo->dst_gid));
        if (rds_conn_state(conn) == RDS_CONN_UP) {
                struct rds_iw_device *rds_iwdev;
                struct rdma_dev_addr *dev_addr;

                ic = conn->c_transport_data;
                dev_addr = &ic->i_cm_id->route.addr.dev_addr;

                rdma_addr_get_sgid(dev_addr, (union ib_gid *) &iinfo->src_gid);
                rdma_addr_get_dgid(dev_addr, (union ib_gid *) &iinfo->dst_gid);

                rds_iwdev = ib_get_client_data(ic->i_cm_id->device, &rds_iw_client);
                iinfo->max_send_wr = ic->i_send_ring.w_nr;
                iinfo->max_recv_wr = ic->i_recv_ring.w_nr;
                iinfo->max_send_sge = rds_iwdev->max_sge;
                rds_iw_get_mr_info(rds_iwdev, iinfo);
        }
        return 1;
}

static void rds_iw_ic_info(struct socket *sock, unsigned int len,
                           struct rds_info_iterator *iter,
                           struct rds_info_lengths *lens)
{
        rds_for_each_conn_info(sock, len, iter, lens,
                                rds_iw_conn_info_visitor,
                                sizeof(struct rds_info_rdma_connection));
}


/*
 * Early RDS/IB was built to only bind to an address if there is an IPoIB
 * device with that address set.
 *
 * If it were me, I'd advocate for something more flexible.  Sending and
 * receiving should be device-agnostic.  Transports would try and maintain
 * connections between peers who have messages queued.  Userspace would be
 * allowed to influence which paths have priority.  We could call userspace
 * asserting this policy "routing".
 */
static int rds_iw_laddr_check(__be32 addr)
{
        int ret;
        struct rdma_cm_id *cm_id;
        struct sockaddr_in sin;

        /* Create a CMA ID and try to bind it. This catches both
         * IB and iWARP capable NICs.
         */
        cm_id = rdma_create_id(NULL, NULL, RDMA_PS_TCP, IB_QPT_RC);
        if (IS_ERR(cm_id))
                return PTR_ERR(cm_id);

        memset(&sin, 0, sizeof(sin));
        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = addr;

        /* rdma_bind_addr will only succeed for IB & iWARP devices */
        ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin);
        /* due to this, we will claim to support IB devices unless we
           check node_type. */
        if (ret || !cm_id->device ||
            cm_id->device->node_type != RDMA_NODE_RNIC)
                ret = -EADDRNOTAVAIL;

        rdsdebug("addr %pI4 ret %d node type %d\n",
                &addr, ret,
                cm_id->device ? cm_id->device->node_type : -1);

        rdma_destroy_id(cm_id);

        return ret;
}

void rds_iw_exit(void)
{
        rds_info_deregister_func(RDS_INFO_IWARP_CONNECTIONS, rds_iw_ic_info);
        rds_iw_destroy_nodev_conns();
        ib_unregister_client(&rds_iw_client);
        rds_iw_sysctl_exit();
        rds_iw_recv_exit();
        rds_trans_unregister(&rds_iw_transport);
}

struct rds_transport rds_iw_transport = {
        .laddr_check            = rds_iw_laddr_check,
        .xmit_complete          = rds_iw_xmit_complete,
        .xmit                   = rds_iw_xmit,
        .xmit_rdma              = rds_iw_xmit_rdma,
        .recv                   = rds_iw_recv,
        .conn_alloc             = rds_iw_conn_alloc,
        .conn_free              = rds_iw_conn_free,
        .conn_connect           = rds_iw_conn_connect,
        .conn_shutdown          = rds_iw_conn_shutdown,
        .inc_copy_to_user       = rds_iw_inc_copy_to_user,
        .inc_free               = rds_iw_inc_free,
        .cm_initiate_connect    = rds_iw_cm_initiate_connect,
        .cm_handle_connect      = rds_iw_cm_handle_connect,
        .cm_connect_complete    = rds_iw_cm_connect_complete,
        .stats_info_copy        = rds_iw_stats_info_copy,
        .exit                   = rds_iw_exit,
        .get_mr                 = rds_iw_get_mr,
        .sync_mr                = rds_iw_sync_mr,
        .free_mr                = rds_iw_free_mr,
        .flush_mrs              = rds_iw_flush_mrs,
        .t_owner                = THIS_MODULE,
        .t_name                 = "iwarp",
        .t_type                 = RDS_TRANS_IWARP,
        .t_prefer_loopback      = 1,
};

int rds_iw_init(void)
{
        int ret;

        INIT_LIST_HEAD(&rds_iw_devices);

        ret = ib_register_client(&rds_iw_client);
        if (ret)
                goto out;

        ret = rds_iw_sysctl_init();
        if (ret)
                goto out_ibreg;

        ret = rds_iw_recv_init();
        if (ret)
                goto out_sysctl;

        ret = rds_trans_register(&rds_iw_transport);
        if (ret)
                goto out_recv;

        rds_info_register_func(RDS_INFO_IWARP_CONNECTIONS, rds_iw_ic_info);

        goto out;

out_recv:
        rds_iw_recv_exit();
out_sysctl:
        rds_iw_sysctl_exit();
out_ibreg:
        ib_unregister_client(&rds_iw_client);
out:
        return ret;
}

MODULE_LICENSE("GPL");