/*
 * Copyright (c) 2006, 2007, 2008 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/sched.h>
#include <rdma/ib_smi.h>

#include "ipath_verbs.h"
#include "ipath_kernel.h"

/**
 * ipath_ud_loopback - handle send on loopback QPs
 * @sqp: the sending QP
 * @swqe: the send work request
 *
 * This is called from ipath_make_ud_req() to forward a WQE addressed
 * to the same HCA.
 * Note that the receive interrupt handler may be calling ipath_ud_rcv()
 * while this is being called.
 */
static void ipath_ud_loopback(struct ipath_qp *sqp, struct ipath_swqe *swqe)
{
        struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
        struct ipath_qp *qp;
        struct ib_ah_attr *ah_attr;
        unsigned long flags;
        struct ipath_rq *rq;
        struct ipath_srq *srq;
        struct ipath_sge_state rsge;
        struct ipath_sge *sge;
        struct ipath_rwq *wq;
        struct ipath_rwqe *wqe;
        void (*handler)(struct ib_event *, void *);
        struct ib_wc wc;
        u32 tail;
        u32 rlen;
        u32 length;

        qp = ipath_lookup_qpn(&dev->qp_table, swqe->wr.wr.ud.remote_qpn);
        if (!qp || !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
                dev->n_pkt_drops++;
                goto done;
        }

        /*
         * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
         * Qkeys with the high order bit set mean use the
         * qkey from the QP context instead of the WR (see 10.2.5).
         */
        if (unlikely(qp->ibqp.qp_num &&
                     ((int) swqe->wr.wr.ud.remote_qkey < 0 ?
                      sqp->qkey : swqe->wr.wr.ud.remote_qkey) != qp->qkey)) {
                /* XXX OK to lose a count once in a while. */
                dev->qkey_violations++;
                dev->n_pkt_drops++;
                goto drop;
        }

        /*
         * A GRH is expected to precede the data even if not
         * present on the wire.
         */
        length = swqe->length;
        memset(&wc, 0, sizeof wc);
        wc.byte_len = length + sizeof(struct ib_grh);

        if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
                wc.wc_flags = IB_WC_WITH_IMM;
                wc.ex.imm_data = swqe->wr.ex.imm_data;
        }

        /*
         * This would be a lot simpler if we could call ipath_get_rwqe()
         * but that uses state that the receive interrupt handler uses
         * so we would need to lock out receive interrupts while doing
         * local loopback.
         */
        if (qp->ibqp.srq) {
                srq = to_isrq(qp->ibqp.srq);
                handler = srq->ibsrq.event_handler;
                rq = &srq->rq;
        } else {
                srq = NULL;
                handler = NULL;
                rq = &qp->r_rq;
        }

        /*
         * Get the next work request entry to find where to put the data.
         * Note that it is safe to drop the lock after changing rq->tail
         * since ipath_post_receive() won't fill the empty slot.
         */
        spin_lock_irqsave(&rq->lock, flags);
        wq = rq->wq;
        tail = wq->tail;
        /* Validate tail before using it since it is user writable. */
        if (tail >= rq->size)
                tail = 0;
        if (unlikely(tail == wq->head)) {
                spin_unlock_irqrestore(&rq->lock, flags);
                dev->n_pkt_drops++;
                goto drop;
        }
        wqe = get_rwqe_ptr(rq, tail);
        rsge.sg_list = qp->r_ud_sg_list;
        if (!ipath_init_sge(qp, wqe, &rlen, &rsge)) {
                spin_unlock_irqrestore(&rq->lock, flags);
                dev->n_pkt_drops++;
                goto drop;
        }
        /* Silently drop packets which are too big. */
        if (wc.byte_len > rlen) {
                spin_unlock_irqrestore(&rq->lock, flags);
                dev->n_pkt_drops++;
                goto drop;
        }
        if (++tail >= rq->size)
                tail = 0;
        wq->tail = tail;
        wc.wr_id = wqe->wr_id;
        if (handler) {
                u32 n;

                /*
                 * validate head pointer value and compute
                 * the number of remaining WQEs.
                 */
                n = wq->head;
                if (n >= rq->size)
                        n = 0;
                if (n < tail)
                        n += rq->size - tail;
                else
                        n -= tail;
                if (n < srq->limit) {
                        struct ib_event ev;

                        srq->limit = 0;
                        spin_unlock_irqrestore(&rq->lock, flags);
                        ev.device = qp->ibqp.device;
                        ev.element.srq = qp->ibqp.srq;
                        ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
                        handler(&ev, srq->ibsrq.srq_context);
                } else
                        spin_unlock_irqrestore(&rq->lock, flags);
        } else
                spin_unlock_irqrestore(&rq->lock, flags);

        ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
        if (ah_attr->ah_flags & IB_AH_GRH) {
                ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
                wc.wc_flags |= IB_WC_GRH;
        } else
                ipath_skip_sge(&rsge, sizeof(struct ib_grh));
        sge = swqe->sg_list;
        while (length) {
                u32 len = sge->length;

                if (len > length)
                        len = length;
                if (len > sge->sge_length)
                        len = sge->sge_length;
                BUG_ON(len == 0);
                ipath_copy_sge(&rsge, sge->vaddr, len);
                sge->vaddr += len;
                sge->length -= len;
                sge->sge_length -= len;
                if (sge->sge_length == 0) {
                        if (--swqe->wr.num_sge)
                                sge++;
                } else if (sge->length == 0 && sge->mr != NULL) {
                        if (++sge->n >= IPATH_SEGSZ) {
                                if (++sge->m >= sge->mr->mapsz)
                                        break;
                                sge->n = 0;
                        }
                        sge->vaddr =
                                sge->mr->map[sge->m]->segs[sge->n].vaddr;
                        sge->length =
                                sge->mr->map[sge->m]->segs[sge->n].length;
                }
                length -= len;
        }
        wc.status = IB_WC_SUCCESS;
        wc.opcode = IB_WC_RECV;
        wc.qp = &qp->ibqp;
        wc.src_qp = sqp->ibqp.qp_num;
        /* XXX do we know which pkey matched? Only needed for GSI. */
        wc.pkey_index = 0;
        wc.slid = dev->dd->ipath_lid |
                (ah_attr->src_path_bits &
                 ((1 << dev->dd->ipath_lmc) - 1));
        wc.sl = ah_attr->sl;
        wc.dlid_path_bits =
                ah_attr->dlid & ((1 << dev->dd->ipath_lmc) - 1);
        wc.port_num = 1;
        /* Signal completion event if the solicited bit is set. */
        ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
                       swqe->wr.send_flags & IB_SEND_SOLICITED);
drop:
        if (atomic_dec_and_test(&qp->refcount))
                wake_up(&qp->wait);
done:;
}

/**
 * ipath_make_ud_req - construct a UD request packet
 * @qp: the QP
 *
 * Return 1 if constructed; otherwise, return 0.
 */
int ipath_make_ud_req(struct ipath_qp *qp)
{
        struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
        struct ipath_other_headers *ohdr;
        struct ib_ah_attr *ah_attr;
        struct ipath_swqe *wqe;
        unsigned long flags;
        u32 nwords;
        u32 extra_bytes;
        u32 bth0;
        u16 lrh0;
        u16 lid;
        int ret = 0;
        int next_cur;

        spin_lock_irqsave(&qp->s_lock, flags);

        if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
                if (!(ib_ipath_state_ops[qp->state] & IPATH_FLUSH_SEND))
                        goto bail;
                /* We are in the error state, flush the work request. */
                if (qp->s_last == qp->s_head)
                        goto bail;
                /* If DMAs are in progress, we can't flush immediately. */
                if (atomic_read(&qp->s_dma_busy)) {
                        qp->s_flags |= IPATH_S_WAIT_DMA;
                        goto bail;
                }
                wqe = get_swqe_ptr(qp, qp->s_last);
                ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
                goto done;
        }

        if (qp->s_cur == qp->s_head)
                goto bail;

        wqe = get_swqe_ptr(qp, qp->s_cur);
        next_cur = qp->s_cur + 1;
        if (next_cur >= qp->s_size)
                next_cur = 0;

        /* Construct the header. */
        ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
        if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
                if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
                        dev->n_multicast_xmit++;
                else
                        dev->n_unicast_xmit++;
        } else {
                dev->n_unicast_xmit++;
                lid = ah_attr->dlid & ~((1 << dev->dd->ipath_lmc) - 1);
                if (unlikely(lid == dev->dd->ipath_lid)) {
                        /*
                         * If DMAs are in progress, we can't generate
                         * a completion for the loopback packet since
                         * it would be out of order.
                         * XXX Instead of waiting, we could queue a
                         * zero length descriptor so we get a callback.
                         */
                        if (atomic_read(&qp->s_dma_busy)) {
                                qp->s_flags |= IPATH_S_WAIT_DMA;
                                goto bail;
                        }
                        qp->s_cur = next_cur;
                        spin_unlock_irqrestore(&qp->s_lock, flags);
                        ipath_ud_loopback(qp, wqe);
                        spin_lock_irqsave(&qp->s_lock, flags);
                        ipath_send_complete(qp, wqe, IB_WC_SUCCESS);
                        goto done;
                }
        }

        qp->s_cur = next_cur;
        extra_bytes = -wqe->length & 3;
        nwords = (wqe->length + extra_bytes) >> 2;

        /* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
        qp->s_hdrwords = 7;
        qp->s_cur_size = wqe->length;
        qp->s_cur_sge = &qp->s_sge;
        qp->s_dmult = ah_attr->static_rate;
        qp->s_wqe = wqe;
        qp->s_sge.sge = wqe->sg_list[0];
        qp->s_sge.sg_list = wqe->sg_list + 1;
        qp->s_sge.num_sge = wqe->wr.num_sge;

        if (ah_attr->ah_flags & IB_AH_GRH) {
                /* Header size in 32-bit words. */
                qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
                                                 &ah_attr->grh,
                                                 qp->s_hdrwords, nwords);
                lrh0 = IPATH_LRH_GRH;
                ohdr = &qp->s_hdr.u.l.oth;
                /*
                 * Don't worry about sending to locally attached multicast
                 * QPs.  It is unspecified by the spec. what happens.
                 */
        } else {
                /* Header size in 32-bit words. */
                lrh0 = IPATH_LRH_BTH;
                ohdr = &qp->s_hdr.u.oth;
        }
        if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
                qp->s_hdrwords++;
                ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
                bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
        } else
                bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
        lrh0 |= ah_attr->sl << 4;
        if (qp->ibqp.qp_type == IB_QPT_SMI)
                lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
        qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
        qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
        qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
                                           SIZE_OF_CRC);
        lid = dev->dd->ipath_lid;
        if (lid) {
                lid |= ah_attr->src_path_bits &
                        ((1 << dev->dd->ipath_lmc) - 1);
                qp->s_hdr.lrh[3] = cpu_to_be16(lid);
        } else
                qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
        if (wqe->wr.send_flags & IB_SEND_SOLICITED)
                bth0 |= 1 << 23;
        bth0 |= extra_bytes << 20;
        bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
                ipath_get_pkey(dev->dd, qp->s_pkey_index);
        ohdr->bth[0] = cpu_to_be32(bth0);
        /*
         * Use the multicast QP if the destination LID is a multicast LID.
         */
        ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
                ah_attr->dlid != IPATH_PERMISSIVE_LID ?
                cpu_to_be32(IPATH_MULTICAST_QPN) :
                cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
        ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
        /*
         * Qkeys with the high order bit set mean use the
         * qkey from the QP context instead of the WR (see 10.2.5).
         */
        ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
                                         qp->qkey : wqe->wr.wr.ud.remote_qkey);
        ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);

done:
        ret = 1;
        goto unlock;

bail:
        qp->s_flags &= ~IPATH_S_BUSY;
unlock:
        spin_unlock_irqrestore(&qp->s_lock, flags);
        return ret;
}

/**
 * ipath_ud_rcv - receive an incoming UD packet
 * @dev: the device the packet came in on
 * @hdr: the packet header
 * @has_grh: true if the packet has a GRH
 * @data: the packet data
 * @tlen: the packet length
 * @qp: the QP the packet came on
 *
 * This is called from ipath_qp_rcv() to process an incoming UD packet
 * for the given QP.
 * Called at interrupt level.
 */
void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
                  int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
{
        struct ipath_other_headers *ohdr;
        int opcode;
        u32 hdrsize;
        u32 pad;
        struct ib_wc wc;
        u32 qkey;
        u32 src_qp;
        u16 dlid;
        int header_in_data;

        /* Check for GRH */
        if (!has_grh) {
                ohdr = &hdr->u.oth;
                hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
                qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
                src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
                header_in_data = 0;
        } else {
                ohdr = &hdr->u.l.oth;
                hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
                /*
                 * The header with GRH is 68 bytes and the core driver sets
                 * the eager header buffer size to 56 bytes so the last 12
                 * bytes of the IB header is in the data buffer.
                 */
                header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
                if (header_in_data) {
                        qkey = be32_to_cpu(((__be32 *) data)[1]);
                        src_qp = be32_to_cpu(((__be32 *) data)[2]);
                        data += 12;
                } else {
                        qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
                        src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
                }
        }
        src_qp &= IPATH_QPN_MASK;

        /*
         * Check that the permissive LID is only used on QP0
         * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
         */
        if (qp->ibqp.qp_num) {
                if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
                             hdr->lrh[3] == IB_LID_PERMISSIVE)) {
                        dev->n_pkt_drops++;
                        goto bail;
                }
                if (unlikely(qkey != qp->qkey)) {
                        /* XXX OK to lose a count once in a while. */
                        dev->qkey_violations++;
                        dev->n_pkt_drops++;
                        goto bail;
                }
        } else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
                   hdr->lrh[3] == IB_LID_PERMISSIVE) {
                struct ib_smp *smp = (struct ib_smp *) data;

                if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
                        dev->n_pkt_drops++;
                        goto bail;
                }
        }

        /*
         * The opcode is in the low byte when its in network order
         * (top byte when in host order).
         */
        opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
        if (qp->ibqp.qp_num > 1 &&
            opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
                if (header_in_data) {
                        wc.ex.imm_data = *(__be32 *) data;
                        data += sizeof(__be32);
                } else
                        wc.ex.imm_data = ohdr->u.ud.imm_data;
                wc.wc_flags = IB_WC_WITH_IMM;
                hdrsize += sizeof(u32);
        } else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
                wc.ex.imm_data = 0;
                wc.wc_flags = 0;
        } else {
                dev->n_pkt_drops++;
                goto bail;
        }

        /* Get the number of bytes the message was padded by. */
        pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
        if (unlikely(tlen < (hdrsize + pad + 4))) {
                /* Drop incomplete packets. */
                dev->n_pkt_drops++;
                goto bail;
        }
        tlen -= hdrsize + pad + 4;

        /* Drop invalid MAD packets (see 13.5.3.1). */
        if (unlikely((qp->ibqp.qp_num == 0 &&
                      (tlen != 256 ||
                       (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
                     (qp->ibqp.qp_num == 1 &&
                      (tlen != 256 ||
                       (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
                dev->n_pkt_drops++;
                goto bail;
        }

        /*
         * A GRH is expected to precede the data even if not
         * present on the wire.
         */
        wc.byte_len = tlen + sizeof(struct ib_grh);

        /*
         * Get the next work request entry to find where to put the data.
         */
        if (qp->r_flags & IPATH_R_REUSE_SGE)
                qp->r_flags &= ~IPATH_R_REUSE_SGE;
        else if (!ipath_get_rwqe(qp, 0)) {
                /*
                 * Count VL15 packets dropped due to no receive buffer.
                 * Otherwise, count them as buffer overruns since usually,
                 * the HW will be able to receive packets even if there are
                 * no QPs with posted receive buffers.
                 */
                if (qp->ibqp.qp_num == 0)
                        dev->n_vl15_dropped++;
                else
                        dev->rcv_errors++;
                goto bail;
        }
        /* Silently drop packets which are too big. */
        if (wc.byte_len > qp->r_len) {
                qp->r_flags |= IPATH_R_REUSE_SGE;
                dev->n_pkt_drops++;
                goto bail;
        }
        if (has_grh) {
                ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
                               sizeof(struct ib_grh));
                wc.wc_flags |= IB_WC_GRH;
        } else
                ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
        ipath_copy_sge(&qp->r_sge, data,
                       wc.byte_len - sizeof(struct ib_grh));
        if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
                goto bail;
        wc.wr_id = qp->r_wr_id;
        wc.status = IB_WC_SUCCESS;
        wc.opcode = IB_WC_RECV;
        wc.vendor_err = 0;
        wc.qp = &qp->ibqp;
        wc.src_qp = src_qp;
        /* XXX do we know which pkey matched? Only needed for GSI. */
        wc.pkey_index = 0;
        wc.slid = be16_to_cpu(hdr->lrh[3]);
        wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
        dlid = be16_to_cpu(hdr->lrh[1]);
        /*
         * Save the LMC lower bits if the destination LID is a unicast LID.
         */
        wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
                dlid & ((1 << dev->dd->ipath_lmc) - 1);
        wc.port_num = 1;
        /* Signal completion event if the solicited bit is set. */
        ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
                       (ohdr->bth[0] &
                        cpu_to_be32(1 << 23)) != 0);

bail:;
}