x86/amd-iommu: Add function to complete a tlb flush

[linux/fpc-iii.git] / drivers / infiniband / hw / amso1100 / c2_qp.c

/*
 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Cisco Systems. All rights reserved.
 * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
 * Copyright (c) 2004 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2005 Open Grid Computing, Inc. 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/delay.h>

#include "c2.h"
#include "c2_vq.h"
#include "c2_status.h"

#define C2_MAX_ORD_PER_QP 128
#define C2_MAX_IRD_PER_QP 128

#define C2_HINT_MAKE(q_index, hint_count) (((q_index) << 16) | hint_count)
#define C2_HINT_GET_INDEX(hint) (((hint) & 0x7FFF0000) >> 16)
#define C2_HINT_GET_COUNT(hint) ((hint) & 0x0000FFFF)

#define NO_SUPPORT -1
static const u8 c2_opcode[] = {
        [IB_WR_SEND] = C2_WR_TYPE_SEND,
        [IB_WR_SEND_WITH_IMM] = NO_SUPPORT,
        [IB_WR_RDMA_WRITE] = C2_WR_TYPE_RDMA_WRITE,
        [IB_WR_RDMA_WRITE_WITH_IMM] = NO_SUPPORT,
        [IB_WR_RDMA_READ] = C2_WR_TYPE_RDMA_READ,
        [IB_WR_ATOMIC_CMP_AND_SWP] = NO_SUPPORT,
        [IB_WR_ATOMIC_FETCH_AND_ADD] = NO_SUPPORT,
};

static int to_c2_state(enum ib_qp_state ib_state)
{
        switch (ib_state) {
        case IB_QPS_RESET:
                return C2_QP_STATE_IDLE;
        case IB_QPS_RTS:
                return C2_QP_STATE_RTS;
        case IB_QPS_SQD:
                return C2_QP_STATE_CLOSING;
        case IB_QPS_SQE:
                return C2_QP_STATE_CLOSING;
        case IB_QPS_ERR:
                return C2_QP_STATE_ERROR;
        default:
                return -1;
        }
}

static int to_ib_state(enum c2_qp_state c2_state)
{
        switch (c2_state) {
        case C2_QP_STATE_IDLE:
                return IB_QPS_RESET;
        case C2_QP_STATE_CONNECTING:
                return IB_QPS_RTR;
        case C2_QP_STATE_RTS:
                return IB_QPS_RTS;
        case C2_QP_STATE_CLOSING:
                return IB_QPS_SQD;
        case C2_QP_STATE_ERROR:
                return IB_QPS_ERR;
        case C2_QP_STATE_TERMINATE:
                return IB_QPS_SQE;
        default:
                return -1;
        }
}

static const char *to_ib_state_str(int ib_state)
{
        static const char *state_str[] = {
                "IB_QPS_RESET",
                "IB_QPS_INIT",
                "IB_QPS_RTR",
                "IB_QPS_RTS",
                "IB_QPS_SQD",
                "IB_QPS_SQE",
                "IB_QPS_ERR"
        };
        if (ib_state < IB_QPS_RESET ||
            ib_state > IB_QPS_ERR)
                return "<invalid IB QP state>";

        ib_state -= IB_QPS_RESET;
        return state_str[ib_state];
}

void c2_set_qp_state(struct c2_qp *qp, int c2_state)
{
        int new_state = to_ib_state(c2_state);

        pr_debug("%s: qp[%p] state modify %s --> %s\n",
               __func__,
                qp,
                to_ib_state_str(qp->state),
                to_ib_state_str(new_state));
        qp->state = new_state;
}

#define C2_QP_NO_ATTR_CHANGE 0xFFFFFFFF

int c2_qp_modify(struct c2_dev *c2dev, struct c2_qp *qp,
                 struct ib_qp_attr *attr, int attr_mask)
{
        struct c2wr_qp_modify_req wr;
        struct c2wr_qp_modify_rep *reply;
        struct c2_vq_req *vq_req;
        unsigned long flags;
        u8 next_state;
        int err;

        pr_debug("%s:%d qp=%p, %s --> %s\n",
                __func__, __LINE__,
                qp,
                to_ib_state_str(qp->state),
                to_ib_state_str(attr->qp_state));

        vq_req = vq_req_alloc(c2dev);
        if (!vq_req)
                return -ENOMEM;

        c2_wr_set_id(&wr, CCWR_QP_MODIFY);
        wr.hdr.context = (unsigned long) vq_req;
        wr.rnic_handle = c2dev->adapter_handle;
        wr.qp_handle = qp->adapter_handle;
        wr.ord = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);
        wr.ird = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);
        wr.sq_depth = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);
        wr.rq_depth = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);

        if (attr_mask & IB_QP_STATE) {
                /* Ensure the state is valid */
                if (attr->qp_state < 0 || attr->qp_state > IB_QPS_ERR) {
                        err = -EINVAL;
                        goto bail0;
                }

                wr.next_qp_state = cpu_to_be32(to_c2_state(attr->qp_state));

                if (attr->qp_state == IB_QPS_ERR) {
                        spin_lock_irqsave(&qp->lock, flags);
                        if (qp->cm_id && qp->state == IB_QPS_RTS) {
                                pr_debug("Generating CLOSE event for QP-->ERR, "
                                        "qp=%p, cm_id=%p\n",qp,qp->cm_id);
                                /* Generate an CLOSE event */
                                vq_req->cm_id = qp->cm_id;
                                vq_req->event = IW_CM_EVENT_CLOSE;
                        }
                        spin_unlock_irqrestore(&qp->lock, flags);
                }
                next_state =  attr->qp_state;

        } else if (attr_mask & IB_QP_CUR_STATE) {

                if (attr->cur_qp_state != IB_QPS_RTR &&
                    attr->cur_qp_state != IB_QPS_RTS &&
                    attr->cur_qp_state != IB_QPS_SQD &&
                    attr->cur_qp_state != IB_QPS_SQE) {
                        err = -EINVAL;
                        goto bail0;
                } else
                        wr.next_qp_state =
                            cpu_to_be32(to_c2_state(attr->cur_qp_state));

                next_state = attr->cur_qp_state;

        } else {
                err = 0;
                goto bail0;
        }

        /* reference the request struct */
        vq_req_get(c2dev, vq_req);

        err = vq_send_wr(c2dev, (union c2wr *) & wr);
        if (err) {
                vq_req_put(c2dev, vq_req);
                goto bail0;
        }

        err = vq_wait_for_reply(c2dev, vq_req);
        if (err)
                goto bail0;

        reply = (struct c2wr_qp_modify_rep *) (unsigned long) vq_req->reply_msg;
        if (!reply) {
                err = -ENOMEM;
                goto bail0;
        }

        err = c2_errno(reply);
        if (!err)
                qp->state = next_state;
#ifdef DEBUG
        else
                pr_debug("%s: c2_errno=%d\n", __func__, err);
#endif
        /*
         * If we're going to error and generating the event here, then
         * we need to remove the reference because there will be no
         * close event generated by the adapter
        */
        spin_lock_irqsave(&qp->lock, flags);
        if (vq_req->event==IW_CM_EVENT_CLOSE && qp->cm_id) {
                qp->cm_id->rem_ref(qp->cm_id);
                qp->cm_id = NULL;
        }
        spin_unlock_irqrestore(&qp->lock, flags);

        vq_repbuf_free(c2dev, reply);
      bail0:
        vq_req_free(c2dev, vq_req);

        pr_debug("%s:%d qp=%p, cur_state=%s\n",
                __func__, __LINE__,
                qp,
                to_ib_state_str(qp->state));
        return err;
}

int c2_qp_set_read_limits(struct c2_dev *c2dev, struct c2_qp *qp,
                          int ord, int ird)
{
        struct c2wr_qp_modify_req wr;
        struct c2wr_qp_modify_rep *reply;
        struct c2_vq_req *vq_req;
        int err;

        vq_req = vq_req_alloc(c2dev);
        if (!vq_req)
                return -ENOMEM;

        c2_wr_set_id(&wr, CCWR_QP_MODIFY);
        wr.hdr.context = (unsigned long) vq_req;
        wr.rnic_handle = c2dev->adapter_handle;
        wr.qp_handle = qp->adapter_handle;
        wr.ord = cpu_to_be32(ord);
        wr.ird = cpu_to_be32(ird);
        wr.sq_depth = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);
        wr.rq_depth = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);
        wr.next_qp_state = cpu_to_be32(C2_QP_NO_ATTR_CHANGE);

        /* reference the request struct */
        vq_req_get(c2dev, vq_req);

        err = vq_send_wr(c2dev, (union c2wr *) & wr);
        if (err) {
                vq_req_put(c2dev, vq_req);
                goto bail0;
        }

        err = vq_wait_for_reply(c2dev, vq_req);
        if (err)
                goto bail0;

        reply = (struct c2wr_qp_modify_rep *) (unsigned long)
                vq_req->reply_msg;
        if (!reply) {
                err = -ENOMEM;
                goto bail0;
        }

        err = c2_errno(reply);
        vq_repbuf_free(c2dev, reply);
      bail0:
        vq_req_free(c2dev, vq_req);
        return err;
}

static int destroy_qp(struct c2_dev *c2dev, struct c2_qp *qp)
{
        struct c2_vq_req *vq_req;
        struct c2wr_qp_destroy_req wr;
        struct c2wr_qp_destroy_rep *reply;
        unsigned long flags;
        int err;

        /*
         * Allocate a verb request message
         */
        vq_req = vq_req_alloc(c2dev);
        if (!vq_req) {
                return -ENOMEM;
        }

        /*
         * Initialize the WR
         */
        c2_wr_set_id(&wr, CCWR_QP_DESTROY);
        wr.hdr.context = (unsigned long) vq_req;
        wr.rnic_handle = c2dev->adapter_handle;
        wr.qp_handle = qp->adapter_handle;

        /*
         * reference the request struct.  dereferenced in the int handler.
         */
        vq_req_get(c2dev, vq_req);

        spin_lock_irqsave(&qp->lock, flags);
        if (qp->cm_id && qp->state == IB_QPS_RTS) {
                pr_debug("destroy_qp: generating CLOSE event for QP-->ERR, "
                        "qp=%p, cm_id=%p\n",qp,qp->cm_id);
                /* Generate an CLOSE event */
                vq_req->qp = qp;
                vq_req->cm_id = qp->cm_id;
                vq_req->event = IW_CM_EVENT_CLOSE;
        }
        spin_unlock_irqrestore(&qp->lock, flags);

        /*
         * Send WR to adapter
         */
        err = vq_send_wr(c2dev, (union c2wr *) & wr);
        if (err) {
                vq_req_put(c2dev, vq_req);
                goto bail0;
        }

        /*
         * Wait for reply from adapter
         */
        err = vq_wait_for_reply(c2dev, vq_req);
        if (err) {
                goto bail0;
        }

        /*
         * Process reply
         */
        reply = (struct c2wr_qp_destroy_rep *) (unsigned long) (vq_req->reply_msg);
        if (!reply) {
                err = -ENOMEM;
                goto bail0;
        }

        spin_lock_irqsave(&qp->lock, flags);
        if (qp->cm_id) {
                qp->cm_id->rem_ref(qp->cm_id);
                qp->cm_id = NULL;
        }
        spin_unlock_irqrestore(&qp->lock, flags);

        vq_repbuf_free(c2dev, reply);
      bail0:
        vq_req_free(c2dev, vq_req);
        return err;
}

static int c2_alloc_qpn(struct c2_dev *c2dev, struct c2_qp *qp)
{
        int ret;

        do {
                spin_lock_irq(&c2dev->qp_table.lock);
                ret = idr_get_new_above(&c2dev->qp_table.idr, qp,
                                        c2dev->qp_table.last++, &qp->qpn);
                spin_unlock_irq(&c2dev->qp_table.lock);
        } while ((ret == -EAGAIN) &&
                 idr_pre_get(&c2dev->qp_table.idr, GFP_KERNEL));
        return ret;
}

static void c2_free_qpn(struct c2_dev *c2dev, int qpn)
{
        spin_lock_irq(&c2dev->qp_table.lock);
        idr_remove(&c2dev->qp_table.idr, qpn);
        spin_unlock_irq(&c2dev->qp_table.lock);
}

struct c2_qp *c2_find_qpn(struct c2_dev *c2dev, int qpn)
{
        unsigned long flags;
        struct c2_qp *qp;

        spin_lock_irqsave(&c2dev->qp_table.lock, flags);
        qp = idr_find(&c2dev->qp_table.idr, qpn);
        spin_unlock_irqrestore(&c2dev->qp_table.lock, flags);
        return qp;
}

int c2_alloc_qp(struct c2_dev *c2dev,
                struct c2_pd *pd,
                struct ib_qp_init_attr *qp_attrs, struct c2_qp *qp)
{
        struct c2wr_qp_create_req wr;
        struct c2wr_qp_create_rep *reply;
        struct c2_vq_req *vq_req;
        struct c2_cq *send_cq = to_c2cq(qp_attrs->send_cq);
        struct c2_cq *recv_cq = to_c2cq(qp_attrs->recv_cq);
        unsigned long peer_pa;
        u32 q_size, msg_size, mmap_size;
        void __iomem *mmap;
        int err;

        err = c2_alloc_qpn(c2dev, qp);
        if (err)
                return err;
        qp->ibqp.qp_num = qp->qpn;
        qp->ibqp.qp_type = IB_QPT_RC;

        /* Allocate the SQ and RQ shared pointers */
        qp->sq_mq.shared = c2_alloc_mqsp(c2dev, c2dev->kern_mqsp_pool,
                                         &qp->sq_mq.shared_dma, GFP_KERNEL);
        if (!qp->sq_mq.shared) {
                err = -ENOMEM;
                goto bail0;
        }

        qp->rq_mq.shared = c2_alloc_mqsp(c2dev, c2dev->kern_mqsp_pool,
                                         &qp->rq_mq.shared_dma, GFP_KERNEL);
        if (!qp->rq_mq.shared) {
                err = -ENOMEM;
                goto bail1;
        }

        /* Allocate the verbs request */
        vq_req = vq_req_alloc(c2dev);
        if (vq_req == NULL) {
                err = -ENOMEM;
                goto bail2;
        }

        /* Initialize the work request */
        memset(&wr, 0, sizeof(wr));
        c2_wr_set_id(&wr, CCWR_QP_CREATE);
        wr.hdr.context = (unsigned long) vq_req;
        wr.rnic_handle = c2dev->adapter_handle;
        wr.sq_cq_handle = send_cq->adapter_handle;
        wr.rq_cq_handle = recv_cq->adapter_handle;
        wr.sq_depth = cpu_to_be32(qp_attrs->cap.max_send_wr + 1);
        wr.rq_depth = cpu_to_be32(qp_attrs->cap.max_recv_wr + 1);
        wr.srq_handle = 0;
        wr.flags = cpu_to_be32(QP_RDMA_READ | QP_RDMA_WRITE | QP_MW_BIND |
                               QP_ZERO_STAG | QP_RDMA_READ_RESPONSE);
        wr.send_sgl_depth = cpu_to_be32(qp_attrs->cap.max_send_sge);
        wr.recv_sgl_depth = cpu_to_be32(qp_attrs->cap.max_recv_sge);
        wr.rdma_write_sgl_depth = cpu_to_be32(qp_attrs->cap.max_send_sge);
        wr.shared_sq_ht = cpu_to_be64(qp->sq_mq.shared_dma);
        wr.shared_rq_ht = cpu_to_be64(qp->rq_mq.shared_dma);
        wr.ord = cpu_to_be32(C2_MAX_ORD_PER_QP);
        wr.ird = cpu_to_be32(C2_MAX_IRD_PER_QP);
        wr.pd_id = pd->pd_id;
        wr.user_context = (unsigned long) qp;

        vq_req_get(c2dev, vq_req);

        /* Send the WR to the adapter */
        err = vq_send_wr(c2dev, (union c2wr *) & wr);
        if (err) {
                vq_req_put(c2dev, vq_req);
                goto bail3;
        }

        /* Wait for the verb reply  */
        err = vq_wait_for_reply(c2dev, vq_req);
        if (err) {
                goto bail3;
        }

        /* Process the reply */
        reply = (struct c2wr_qp_create_rep *) (unsigned long) (vq_req->reply_msg);
        if (!reply) {
                err = -ENOMEM;
                goto bail3;
        }

        if ((err = c2_wr_get_result(reply)) != 0) {
                goto bail4;
        }

        /* Fill in the kernel QP struct */
        atomic_set(&qp->refcount, 1);
        qp->adapter_handle = reply->qp_handle;
        qp->state = IB_QPS_RESET;
        qp->send_sgl_depth = qp_attrs->cap.max_send_sge;
        qp->rdma_write_sgl_depth = qp_attrs->cap.max_send_sge;
        qp->recv_sgl_depth = qp_attrs->cap.max_recv_sge;
        init_waitqueue_head(&qp->wait);

        /* Initialize the SQ MQ */
        q_size = be32_to_cpu(reply->sq_depth);
        msg_size = be32_to_cpu(reply->sq_msg_size);
        peer_pa = c2dev->pa + be32_to_cpu(reply->sq_mq_start);
        mmap_size = PAGE_ALIGN(sizeof(struct c2_mq_shared) + msg_size * q_size);
        mmap = ioremap_nocache(peer_pa, mmap_size);
        if (!mmap) {
                err = -ENOMEM;
                goto bail5;
        }

        c2_mq_req_init(&qp->sq_mq,
                       be32_to_cpu(reply->sq_mq_index),
                       q_size,
                       msg_size,
                       mmap + sizeof(struct c2_mq_shared),      /* pool start */
                       mmap,                            /* peer */
                       C2_MQ_ADAPTER_TARGET);

        /* Initialize the RQ mq */
        q_size = be32_to_cpu(reply->rq_depth);
        msg_size = be32_to_cpu(reply->rq_msg_size);
        peer_pa = c2dev->pa + be32_to_cpu(reply->rq_mq_start);
        mmap_size = PAGE_ALIGN(sizeof(struct c2_mq_shared) + msg_size * q_size);
        mmap = ioremap_nocache(peer_pa, mmap_size);
        if (!mmap) {
                err = -ENOMEM;
                goto bail6;
        }

        c2_mq_req_init(&qp->rq_mq,
                       be32_to_cpu(reply->rq_mq_index),
                       q_size,
                       msg_size,
                       mmap + sizeof(struct c2_mq_shared),      /* pool start */
                       mmap,                            /* peer */
                       C2_MQ_ADAPTER_TARGET);

        vq_repbuf_free(c2dev, reply);
        vq_req_free(c2dev, vq_req);

        return 0;

      bail6:
        iounmap(qp->sq_mq.peer);
      bail5:
        destroy_qp(c2dev, qp);
      bail4:
        vq_repbuf_free(c2dev, reply);
      bail3:
        vq_req_free(c2dev, vq_req);
      bail2:
        c2_free_mqsp(qp->rq_mq.shared);
      bail1:
        c2_free_mqsp(qp->sq_mq.shared);
      bail0:
        c2_free_qpn(c2dev, qp->qpn);
        return err;
}

static inline void c2_lock_cqs(struct c2_cq *send_cq, struct c2_cq *recv_cq)
{
        if (send_cq == recv_cq)
                spin_lock_irq(&send_cq->lock);
        else if (send_cq > recv_cq) {
                spin_lock_irq(&send_cq->lock);
                spin_lock_nested(&recv_cq->lock, SINGLE_DEPTH_NESTING);
        } else {
                spin_lock_irq(&recv_cq->lock);
                spin_lock_nested(&send_cq->lock, SINGLE_DEPTH_NESTING);
        }
}

static inline void c2_unlock_cqs(struct c2_cq *send_cq, struct c2_cq *recv_cq)
{
        if (send_cq == recv_cq)
                spin_unlock_irq(&send_cq->lock);
        else if (send_cq > recv_cq) {
                spin_unlock(&recv_cq->lock);
                spin_unlock_irq(&send_cq->lock);
        } else {
                spin_unlock(&send_cq->lock);
                spin_unlock_irq(&recv_cq->lock);
        }
}

void c2_free_qp(struct c2_dev *c2dev, struct c2_qp *qp)
{
        struct c2_cq *send_cq;
        struct c2_cq *recv_cq;

        send_cq = to_c2cq(qp->ibqp.send_cq);
        recv_cq = to_c2cq(qp->ibqp.recv_cq);

        /*
         * Lock CQs here, so that CQ polling code can do QP lookup
         * without taking a lock.
         */
        c2_lock_cqs(send_cq, recv_cq);
        c2_free_qpn(c2dev, qp->qpn);
        c2_unlock_cqs(send_cq, recv_cq);

        /*
         * Destory qp in the rnic...
         */
        destroy_qp(c2dev, qp);

        /*
         * Mark any unreaped CQEs as null and void.
         */
        c2_cq_clean(c2dev, qp, send_cq->cqn);
        if (send_cq != recv_cq)
                c2_cq_clean(c2dev, qp, recv_cq->cqn);
        /*
         * Unmap the MQs and return the shared pointers
         * to the message pool.
         */
        iounmap(qp->sq_mq.peer);
        iounmap(qp->rq_mq.peer);
        c2_free_mqsp(qp->sq_mq.shared);
        c2_free_mqsp(qp->rq_mq.shared);

        atomic_dec(&qp->refcount);
        wait_event(qp->wait, !atomic_read(&qp->refcount));
}

/*
 * Function: move_sgl
 *
 * Description:
 * Move an SGL from the user's work request struct into a CCIL Work Request
 * message, swapping to WR byte order and ensure the total length doesn't
 * overflow.
 *
 * IN:
 * dst          - ptr to CCIL Work Request message SGL memory.
 * src          - ptr to the consumers SGL memory.
 *
 * OUT: none
 *
 * Return:
 * CCIL status codes.
 */
static int
move_sgl(struct c2_data_addr * dst, struct ib_sge *src, int count, u32 * p_len,
         u8 * actual_count)
{
        u32 tot = 0;            /* running total */
        u8 acount = 0;          /* running total non-0 len sge's */

        while (count > 0) {
                /*
                 * If the addition of this SGE causes the
                 * total SGL length to exceed 2^32-1, then
                 * fail-n-bail.
                 *
                 * If the current total plus the next element length
                 * wraps, then it will go negative and be less than the
                 * current total...
                 */
                if ((tot + src->length) < tot) {
                        return -EINVAL;
                }
                /*
                 * Bug: 1456 (as well as 1498 & 1643)
                 * Skip over any sge's supplied with len=0
                 */
                if (src->length) {
                        tot += src->length;
                        dst->stag = cpu_to_be32(src->lkey);
                        dst->to = cpu_to_be64(src->addr);
                        dst->length = cpu_to_be32(src->length);
                        dst++;
                        acount++;
                }
                src++;
                count--;
        }

        if (acount == 0) {
                /*
                 * Bug: 1476 (as well as 1498, 1456 and 1643)
                 * Setup the SGL in the WR to make it easier for the RNIC.
                 * This way, the FW doesn't have to deal with special cases.
                 * Setting length=0 should be sufficient.
                 */
                dst->stag = 0;
                dst->to = 0;
                dst->length = 0;
        }

        *p_len = tot;
        *actual_count = acount;
        return 0;
}

/*
 * Function: c2_activity (private function)
 *
 * Description:
 * Post an mq index to the host->adapter activity fifo.
 *
 * IN:
 * c2dev        - ptr to c2dev structure
 * mq_index     - mq index to post
 * shared       - value most recently written to shared
 *
 * OUT:
 *
 * Return:
 * none
 */
static inline void c2_activity(struct c2_dev *c2dev, u32 mq_index, u16 shared)
{
        /*
         * First read the register to see if the FIFO is full, and if so,
         * spin until it's not.  This isn't perfect -- there is no
         * synchronization among the clients of the register, but in
         * practice it prevents multiple CPU from hammering the bus
         * with PCI RETRY. Note that when this does happen, the card
         * cannot get on the bus and the card and system hang in a
         * deadlock -- thus the need for this code. [TOT]
         */
        while (readl(c2dev->regs + PCI_BAR0_ADAPTER_HINT) & 0x80000000)
                udelay(10);

        __raw_writel(C2_HINT_MAKE(mq_index, shared),
                     c2dev->regs + PCI_BAR0_ADAPTER_HINT);
}

/*
 * Function: qp_wr_post
 *
 * Description:
 * This in-line function allocates a MQ msg, then moves the host-copy of
 * the completed WR into msg.  Then it posts the message.
 *
 * IN:
 * q            - ptr to user MQ.
 * wr           - ptr to host-copy of the WR.
 * qp           - ptr to user qp
 * size         - Number of bytes to post.  Assumed to be divisible by 4.
 *
 * OUT: none
 *
 * Return:
 * CCIL status codes.
 */
static int qp_wr_post(struct c2_mq *q, union c2wr * wr, struct c2_qp *qp, u32 size)
{
        union c2wr *msg;

        msg = c2_mq_alloc(q);
        if (msg == NULL) {
                return -EINVAL;
        }
#ifdef CCMSGMAGIC
        ((c2wr_hdr_t *) wr)->magic = cpu_to_be32(CCWR_MAGIC);
#endif

        /*
         * Since all header fields in the WR are the same as the
         * CQE, set the following so the adapter need not.
         */
        c2_wr_set_result(wr, CCERR_PENDING);

        /*
         * Copy the wr down to the adapter
         */
        memcpy((void *) msg, (void *) wr, size);

        c2_mq_produce(q);
        return 0;
}


int c2_post_send(struct ib_qp *ibqp, struct ib_send_wr *ib_wr,
                 struct ib_send_wr **bad_wr)
{
        struct c2_dev *c2dev = to_c2dev(ibqp->device);
        struct c2_qp *qp = to_c2qp(ibqp);
        union c2wr wr;
        unsigned long lock_flags;
        int err = 0;

        u32 flags;
        u32 tot_len;
        u8 actual_sge_count;
        u32 msg_size;

        if (qp->state > IB_QPS_RTS)
                return -EINVAL;

        while (ib_wr) {

                flags = 0;
                wr.sqwr.sq_hdr.user_hdr.hdr.context = ib_wr->wr_id;
                if (ib_wr->send_flags & IB_SEND_SIGNALED) {
                        flags |= SQ_SIGNALED;
                }

                switch (ib_wr->opcode) {
                case IB_WR_SEND:
                case IB_WR_SEND_WITH_INV:
                        if (ib_wr->opcode == IB_WR_SEND) {
                                if (ib_wr->send_flags & IB_SEND_SOLICITED)
                                        c2_wr_set_id(&wr, C2_WR_TYPE_SEND_SE);
                                else
                                        c2_wr_set_id(&wr, C2_WR_TYPE_SEND);
                                wr.sqwr.send.remote_stag = 0;
                        } else {
                                if (ib_wr->send_flags & IB_SEND_SOLICITED)
                                        c2_wr_set_id(&wr, C2_WR_TYPE_SEND_SE_INV);
                                else
                                        c2_wr_set_id(&wr, C2_WR_TYPE_SEND_INV);
                                wr.sqwr.send.remote_stag =
                                        cpu_to_be32(ib_wr->ex.invalidate_rkey);
                        }

                        msg_size = sizeof(struct c2wr_send_req) +
                                sizeof(struct c2_data_addr) * ib_wr->num_sge;
                        if (ib_wr->num_sge > qp->send_sgl_depth) {
                                err = -EINVAL;
                                break;
                        }
                        if (ib_wr->send_flags & IB_SEND_FENCE) {
                                flags |= SQ_READ_FENCE;
                        }
                        err = move_sgl((struct c2_data_addr *) & (wr.sqwr.send.data),
                                       ib_wr->sg_list,
                                       ib_wr->num_sge,
                                       &tot_len, &actual_sge_count);
                        wr.sqwr.send.sge_len = cpu_to_be32(tot_len);
                        c2_wr_set_sge_count(&wr, actual_sge_count);
                        break;
                case IB_WR_RDMA_WRITE:
                        c2_wr_set_id(&wr, C2_WR_TYPE_RDMA_WRITE);
                        msg_size = sizeof(struct c2wr_rdma_write_req) +
                            (sizeof(struct c2_data_addr) * ib_wr->num_sge);
                        if (ib_wr->num_sge > qp->rdma_write_sgl_depth) {
                                err = -EINVAL;
                                break;
                        }
                        if (ib_wr->send_flags & IB_SEND_FENCE) {
                                flags |= SQ_READ_FENCE;
                        }
                        wr.sqwr.rdma_write.remote_stag =
                            cpu_to_be32(ib_wr->wr.rdma.rkey);
                        wr.sqwr.rdma_write.remote_to =
                            cpu_to_be64(ib_wr->wr.rdma.remote_addr);
                        err = move_sgl((struct c2_data_addr *)
                                       & (wr.sqwr.rdma_write.data),
                                       ib_wr->sg_list,
                                       ib_wr->num_sge,
                                       &tot_len, &actual_sge_count);
                        wr.sqwr.rdma_write.sge_len = cpu_to_be32(tot_len);
                        c2_wr_set_sge_count(&wr, actual_sge_count);
                        break;
                case IB_WR_RDMA_READ:
                        c2_wr_set_id(&wr, C2_WR_TYPE_RDMA_READ);
                        msg_size = sizeof(struct c2wr_rdma_read_req);

                        /* IWarp only suppots 1 sge for RDMA reads */
                        if (ib_wr->num_sge > 1) {
                                err = -EINVAL;
                                break;
                        }

                        /*
                         * Move the local and remote stag/to/len into the WR.
                         */
                        wr.sqwr.rdma_read.local_stag =
                            cpu_to_be32(ib_wr->sg_list->lkey);
                        wr.sqwr.rdma_read.local_to =
                            cpu_to_be64(ib_wr->sg_list->addr);
                        wr.sqwr.rdma_read.remote_stag =
                            cpu_to_be32(ib_wr->wr.rdma.rkey);
                        wr.sqwr.rdma_read.remote_to =
                            cpu_to_be64(ib_wr->wr.rdma.remote_addr);
                        wr.sqwr.rdma_read.length =
                            cpu_to_be32(ib_wr->sg_list->length);
                        break;
                default:
                        /* error */
                        msg_size = 0;
                        err = -EINVAL;
                        break;
                }

                /*
                 * If we had an error on the last wr build, then
                 * break out.  Possible errors include bogus WR
                 * type, and a bogus SGL length...
                 */
                if (err) {
                        break;
                }

                /*
                 * Store flags
                 */
                c2_wr_set_flags(&wr, flags);

                /*
                 * Post the puppy!
                 */
                spin_lock_irqsave(&qp->lock, lock_flags);
                err = qp_wr_post(&qp->sq_mq, &wr, qp, msg_size);
                if (err) {
                        spin_unlock_irqrestore(&qp->lock, lock_flags);
                        break;
                }

                /*
                 * Enqueue mq index to activity FIFO.
                 */
                c2_activity(c2dev, qp->sq_mq.index, qp->sq_mq.hint_count);
                spin_unlock_irqrestore(&qp->lock, lock_flags);

                ib_wr = ib_wr->next;
        }

        if (err)
                *bad_wr = ib_wr;
        return err;
}

int c2_post_receive(struct ib_qp *ibqp, struct ib_recv_wr *ib_wr,
                    struct ib_recv_wr **bad_wr)
{
        struct c2_dev *c2dev = to_c2dev(ibqp->device);
        struct c2_qp *qp = to_c2qp(ibqp);
        union c2wr wr;
        unsigned long lock_flags;
        int err = 0;

        if (qp->state > IB_QPS_RTS)
                return -EINVAL;

        /*
         * Try and post each work request
         */
        while (ib_wr) {
                u32 tot_len;
                u8 actual_sge_count;

                if (ib_wr->num_sge > qp->recv_sgl_depth) {
                        err = -EINVAL;
                        break;
                }

                /*
                 * Create local host-copy of the WR
                 */
                wr.rqwr.rq_hdr.user_hdr.hdr.context = ib_wr->wr_id;
                c2_wr_set_id(&wr, CCWR_RECV);
                c2_wr_set_flags(&wr, 0);

                /* sge_count is limited to eight bits. */
                BUG_ON(ib_wr->num_sge >= 256);
                err = move_sgl((struct c2_data_addr *) & (wr.rqwr.data),
                               ib_wr->sg_list,
                               ib_wr->num_sge, &tot_len, &actual_sge_count);
                c2_wr_set_sge_count(&wr, actual_sge_count);

                /*
                 * If we had an error on the last wr build, then
                 * break out.  Possible errors include bogus WR
                 * type, and a bogus SGL length...
                 */
                if (err) {
                        break;
                }

                spin_lock_irqsave(&qp->lock, lock_flags);
                err = qp_wr_post(&qp->rq_mq, &wr, qp, qp->rq_mq.msg_size);
                if (err) {
                        spin_unlock_irqrestore(&qp->lock, lock_flags);
                        break;
                }

                /*
                 * Enqueue mq index to activity FIFO
                 */
                c2_activity(c2dev, qp->rq_mq.index, qp->rq_mq.hint_count);
                spin_unlock_irqrestore(&qp->lock, lock_flags);

                ib_wr = ib_wr->next;
        }

        if (err)
                *bad_wr = ib_wr;
        return err;
}

void __devinit c2_init_qp_table(struct c2_dev *c2dev)
{
        spin_lock_init(&c2dev->qp_table.lock);
        idr_init(&c2dev->qp_table.idr);
}

void __devexit c2_cleanup_qp_table(struct c2_dev *c2dev)
{
        idr_destroy(&c2dev->qp_table.idr);
}