/*
 * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, 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/spinlock.h>
#include <rdma/ib_smi.h>

#include "qib.h"
#include "qib_mad.h"

/*
 * Switch to alternate path.
 * The QP s_lock should be held and interrupts disabled.
 */
void qib_migrate_qp(struct rvt_qp *qp)
{
        struct ib_event ev;

        qp->s_mig_state = IB_MIG_MIGRATED;
        qp->remote_ah_attr = qp->alt_ah_attr;
        qp->port_num = rdma_ah_get_port_num(&qp->alt_ah_attr);
        qp->s_pkey_index = qp->s_alt_pkey_index;

        ev.device = qp->ibqp.device;
        ev.element.qp = &qp->ibqp;
        ev.event = IB_EVENT_PATH_MIG;
        qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
}

static __be64 get_sguid(struct qib_ibport *ibp, unsigned index)
{
        if (!index) {
                struct qib_pportdata *ppd = ppd_from_ibp(ibp);

                return ppd->guid;
        }
        return ibp->guids[index - 1];
}

static int gid_ok(union ib_gid *gid, __be64 gid_prefix, __be64 id)
{
        return (gid->global.interface_id == id &&
                (gid->global.subnet_prefix == gid_prefix ||
                 gid->global.subnet_prefix == IB_DEFAULT_GID_PREFIX));
}

/*
 *
 * This should be called with the QP r_lock held.
 *
 * The s_lock will be acquired around the qib_migrate_qp() call.
 */
int qib_ruc_check_hdr(struct qib_ibport *ibp, struct ib_header *hdr,
                      int has_grh, struct rvt_qp *qp, u32 bth0)
{
        __be64 guid;
        unsigned long flags;

        if (qp->s_mig_state == IB_MIG_ARMED && (bth0 & IB_BTH_MIG_REQ)) {
                if (!has_grh) {
                        if (rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
                            IB_AH_GRH)
                                goto err;
                } else {
                        const struct ib_global_route *grh;

                        if (!(rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
                              IB_AH_GRH))
                                goto err;
                        grh = rdma_ah_read_grh(&qp->alt_ah_attr);
                        guid = get_sguid(ibp, grh->sgid_index);
                        if (!gid_ok(&hdr->u.l.grh.dgid,
                                    ibp->rvp.gid_prefix, guid))
                                goto err;
                        if (!gid_ok(&hdr->u.l.grh.sgid,
                            grh->dgid.global.subnet_prefix,
                            grh->dgid.global.interface_id))
                                goto err;
                }
                if (!qib_pkey_ok((u16)bth0,
                                 qib_get_pkey(ibp, qp->s_alt_pkey_index))) {
                        qib_bad_pkey(ibp,
                                     (u16)bth0,
                                     (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
                                     0, qp->ibqp.qp_num,
                                     hdr->lrh[3], hdr->lrh[1]);
                        goto err;
                }
                /* Validate the SLID. See Ch. 9.6.1.5 and 17.2.8 */
                if ((be16_to_cpu(hdr->lrh[3]) !=
                     rdma_ah_get_dlid(&qp->alt_ah_attr)) ||
                    ppd_from_ibp(ibp)->port !=
                            rdma_ah_get_port_num(&qp->alt_ah_attr))
                        goto err;
                spin_lock_irqsave(&qp->s_lock, flags);
                qib_migrate_qp(qp);
                spin_unlock_irqrestore(&qp->s_lock, flags);
        } else {
                if (!has_grh) {
                        if (rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
                            IB_AH_GRH)
                                goto err;
                } else {
                        const struct ib_global_route *grh;

                        if (!(rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
                              IB_AH_GRH))
                                goto err;
                        grh = rdma_ah_read_grh(&qp->remote_ah_attr);
                        guid = get_sguid(ibp, grh->sgid_index);
                        if (!gid_ok(&hdr->u.l.grh.dgid,
                                    ibp->rvp.gid_prefix, guid))
                                goto err;
                        if (!gid_ok(&hdr->u.l.grh.sgid,
                            grh->dgid.global.subnet_prefix,
                            grh->dgid.global.interface_id))
                                goto err;
                }
                if (!qib_pkey_ok((u16)bth0,
                                 qib_get_pkey(ibp, qp->s_pkey_index))) {
                        qib_bad_pkey(ibp,
                                     (u16)bth0,
                                     (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
                                     0, qp->ibqp.qp_num,
                                     hdr->lrh[3], hdr->lrh[1]);
                        goto err;
                }
                /* Validate the SLID. See Ch. 9.6.1.5 */
                if (be16_to_cpu(hdr->lrh[3]) !=
                    rdma_ah_get_dlid(&qp->remote_ah_attr) ||
                    ppd_from_ibp(ibp)->port != qp->port_num)
                        goto err;
                if (qp->s_mig_state == IB_MIG_REARM &&
                    !(bth0 & IB_BTH_MIG_REQ))
                        qp->s_mig_state = IB_MIG_ARMED;
        }

        return 0;

err:
        return 1;
}

/**
 * qib_make_grh - construct a GRH header
 * @ibp: a pointer to the IB port
 * @hdr: a pointer to the GRH header being constructed
 * @grh: the global route address to send to
 * @hwords: the number of 32 bit words of header being sent
 * @nwords: the number of 32 bit words of data being sent
 *
 * Return the size of the header in 32 bit words.
 */
u32 qib_make_grh(struct qib_ibport *ibp, struct ib_grh *hdr,
                 const struct ib_global_route *grh, u32 hwords, u32 nwords)
{
        hdr->version_tclass_flow =
                cpu_to_be32((IB_GRH_VERSION << IB_GRH_VERSION_SHIFT) |
                            (grh->traffic_class << IB_GRH_TCLASS_SHIFT) |
                            (grh->flow_label << IB_GRH_FLOW_SHIFT));
        hdr->paylen = cpu_to_be16((hwords - 2 + nwords + SIZE_OF_CRC) << 2);
        /* next_hdr is defined by C8-7 in ch. 8.4.1 */
        hdr->next_hdr = IB_GRH_NEXT_HDR;
        hdr->hop_limit = grh->hop_limit;
        /* The SGID is 32-bit aligned. */
        hdr->sgid.global.subnet_prefix = ibp->rvp.gid_prefix;
        if (!grh->sgid_index)
                hdr->sgid.global.interface_id = ppd_from_ibp(ibp)->guid;
        else if (grh->sgid_index < QIB_GUIDS_PER_PORT)
                hdr->sgid.global.interface_id = ibp->guids[grh->sgid_index - 1];
        hdr->dgid = grh->dgid;

        /* GRH header size in 32-bit words. */
        return sizeof(struct ib_grh) / sizeof(u32);
}

void qib_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
                         u32 bth0, u32 bth2)
{
        struct qib_qp_priv *priv = qp->priv;
        struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
        u16 lrh0;
        u32 nwords;
        u32 extra_bytes;

        /* Construct the header. */
        extra_bytes = -qp->s_cur_size & 3;
        nwords = (qp->s_cur_size + extra_bytes) >> 2;
        lrh0 = QIB_LRH_BTH;
        if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)) {
                qp->s_hdrwords +=
                        qib_make_grh(ibp, &priv->s_hdr->u.l.grh,
                                     rdma_ah_read_grh(&qp->remote_ah_attr),
                                     qp->s_hdrwords, nwords);
                lrh0 = QIB_LRH_GRH;
        }
        lrh0 |= ibp->sl_to_vl[rdma_ah_get_sl(&qp->remote_ah_attr)] << 12 |
                rdma_ah_get_sl(&qp->remote_ah_attr) << 4;
        priv->s_hdr->lrh[0] = cpu_to_be16(lrh0);
        priv->s_hdr->lrh[1] =
                        cpu_to_be16(rdma_ah_get_dlid(&qp->remote_ah_attr));
        priv->s_hdr->lrh[2] =
                        cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
        priv->s_hdr->lrh[3] =
                cpu_to_be16(ppd_from_ibp(ibp)->lid |
                            rdma_ah_get_path_bits(&qp->remote_ah_attr));
        bth0 |= qib_get_pkey(ibp, qp->s_pkey_index);
        bth0 |= extra_bytes << 20;
        if (qp->s_mig_state == IB_MIG_MIGRATED)
                bth0 |= IB_BTH_MIG_REQ;
        ohdr->bth[0] = cpu_to_be32(bth0);
        ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
        ohdr->bth[2] = cpu_to_be32(bth2);
        this_cpu_inc(ibp->pmastats->n_unicast_xmit);
}

void _qib_do_send(struct work_struct *work)
{
        struct qib_qp_priv *priv = container_of(work, struct qib_qp_priv,
                                                s_work);
        struct rvt_qp *qp = priv->owner;

        qib_do_send(qp);
}

/**
 * qib_do_send - perform a send on a QP
 * @qp: pointer to the QP
 *
 * Process entries in the send work queue until credit or queue is
 * exhausted.  Only allow one CPU to send a packet per QP (tasklet).
 * Otherwise, two threads could send packets out of order.
 */
void qib_do_send(struct rvt_qp *qp)
{
        struct qib_qp_priv *priv = qp->priv;
        struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
        struct qib_pportdata *ppd = ppd_from_ibp(ibp);
        int (*make_req)(struct rvt_qp *qp, unsigned long *flags);
        unsigned long flags;

        if ((qp->ibqp.qp_type == IB_QPT_RC ||
             qp->ibqp.qp_type == IB_QPT_UC) &&
            (rdma_ah_get_dlid(&qp->remote_ah_attr) &
             ~((1 << ppd->lmc) - 1)) == ppd->lid) {
                rvt_ruc_loopback(qp);
                return;
        }

        if (qp->ibqp.qp_type == IB_QPT_RC)
                make_req = qib_make_rc_req;
        else if (qp->ibqp.qp_type == IB_QPT_UC)
                make_req = qib_make_uc_req;
        else
                make_req = qib_make_ud_req;

        spin_lock_irqsave(&qp->s_lock, flags);

        /* Return if we are already busy processing a work request. */
        if (!qib_send_ok(qp)) {
                spin_unlock_irqrestore(&qp->s_lock, flags);
                return;
        }

        qp->s_flags |= RVT_S_BUSY;

        do {
                /* Check for a constructed packet to be sent. */
                if (qp->s_hdrwords != 0) {
                        spin_unlock_irqrestore(&qp->s_lock, flags);
                        /*
                         * If the packet cannot be sent now, return and
                         * the send tasklet will be woken up later.
                         */
                        if (qib_verbs_send(qp, priv->s_hdr, qp->s_hdrwords,
                                           qp->s_cur_sge, qp->s_cur_size))
                                return;
                        /* Record that s_hdr is empty. */
                        qp->s_hdrwords = 0;
                        spin_lock_irqsave(&qp->s_lock, flags);
                }
        } while (make_req(qp, &flags));

        spin_unlock_irqrestore(&qp->s_lock, flags);
}