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   1 /*
   2  * Copyright (c) 2006, 2007, 2008 QLogic Corporation. All rights reserved.
   3  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 #include <linux/sched.h>
  35 #include <linux/spinlock.h>
  36
  37 #include "ipath_verbs.h"
  38 #include "ipath_kernel.h"
  39
  40 /*
  41  * Convert the AETH RNR timeout code into the number of milliseconds.
  42  */
  43 const u32 ib_ipath_rnr_table[32] = {
  44         656,                    /* 0 */
  45         1,                      /* 1 */
  46         1,                      /* 2 */
  47         1,                      /* 3 */
  48         1,                      /* 4 */
  49         1,                      /* 5 */
  50         1,                      /* 6 */
  51         1,                      /* 7 */
  52         1,                      /* 8 */
  53         1,                      /* 9 */
  54         1,                      /* A */
  55         1,                      /* B */
  56         1,                      /* C */
  57         1,                      /* D */
  58         2,                      /* E */
  59         2,                      /* F */
  60         3,                      /* 10 */
  61         4,                      /* 11 */
  62         6,                      /* 12 */
  63         8,                      /* 13 */
  64         11,                     /* 14 */
  65         16,                     /* 15 */
  66         21,                     /* 16 */
  67         31,                     /* 17 */
  68         41,                     /* 18 */
  69         62,                     /* 19 */
  70         82,                     /* 1A */
  71         123,                    /* 1B */
  72         164,                    /* 1C */
  73         246,                    /* 1D */
  74         328,                    /* 1E */
  75         492                     /* 1F */
  76 };
  77
  78 /**
  79  * ipath_insert_rnr_queue - put QP on the RNR timeout list for the device
  80  * @qp: the QP
  81  *
  82  * Called with the QP s_lock held and interrupts disabled.
  83  * XXX Use a simple list for now.  We might need a priority
  84  * queue if we have lots of QPs waiting for RNR timeouts
  85  * but that should be rare.
  86  */
  87 void ipath_insert_rnr_queue(struct ipath_qp *qp)
  88 {
  89         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
  90
  91         /* We already did a spin_lock_irqsave(), so just use spin_lock */
  92         spin_lock(&dev->pending_lock);
  93         if (list_empty(&dev->rnrwait))
  94                 list_add(&qp->timerwait, &dev->rnrwait);
  95         else {
  96                 struct list_head *l = &dev->rnrwait;
  97                 struct ipath_qp *nqp = list_entry(l->next, struct ipath_qp,
  98                                                   timerwait);
  99
 100                 while (qp->s_rnr_timeout >= nqp->s_rnr_timeout) {
 101                         qp->s_rnr_timeout -= nqp->s_rnr_timeout;
 102                         l = l->next;
 103                         if (l->next == &dev->rnrwait) {
 104                                 nqp = NULL;
 105                                 break;
 106                         }
 107                         nqp = list_entry(l->next, struct ipath_qp,
 108                                          timerwait);
 109                 }
 110                 if (nqp)
 111                         nqp->s_rnr_timeout -= qp->s_rnr_timeout;
 112                 list_add(&qp->timerwait, l);
 113         }
 114         spin_unlock(&dev->pending_lock);
 115 }
 116
 117 /**
 118  * ipath_init_sge - Validate a RWQE and fill in the SGE state
 119  * @qp: the QP
 120  *
 121  * Return 1 if OK.
 122  */
 123 int ipath_init_sge(struct ipath_qp *qp, struct ipath_rwqe *wqe,
 124                    u32 *lengthp, struct ipath_sge_state *ss)
 125 {
 126         int i, j, ret;
 127         struct ib_wc wc;
 128
 129         *lengthp = 0;
 130         for (i = j = 0; i < wqe->num_sge; i++) {
 131                 if (wqe->sg_list[i].length == 0)
 132                         continue;
 133                 /* Check LKEY */
 134                 if (!ipath_lkey_ok(qp, j ? &ss->sg_list[j - 1] : &ss->sge,
 135                                    &wqe->sg_list[i], IB_ACCESS_LOCAL_WRITE))
 136                         goto bad_lkey;
 137                 *lengthp += wqe->sg_list[i].length;
 138                 j++;
 139         }
 140         ss->num_sge = j;
 141         ret = 1;
 142         goto bail;
 143
 144 bad_lkey:
 145         memset(&wc, 0, sizeof(wc));
 146         wc.wr_id = wqe->wr_id;
 147         wc.status = IB_WC_LOC_PROT_ERR;
 148         wc.opcode = IB_WC_RECV;
 149         wc.qp = &qp->ibqp;
 150         /* Signal solicited completion event. */
 151         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
 152         ret = 0;
 153 bail:
 154         return ret;
 155 }
 156
 157 /**
 158  * ipath_get_rwqe - copy the next RWQE into the QP's RWQE
 159  * @qp: the QP
 160  * @wr_id_only: update qp->r_wr_id only, not qp->r_sge
 161  *
 162  * Return 0 if no RWQE is available, otherwise return 1.
 163  *
 164  * Can be called from interrupt level.
 165  */
 166 int ipath_get_rwqe(struct ipath_qp *qp, int wr_id_only)
 167 {
 168         unsigned long flags;
 169         struct ipath_rq *rq;
 170         struct ipath_rwq *wq;
 171         struct ipath_srq *srq;
 172         struct ipath_rwqe *wqe;
 173         void (*handler)(struct ib_event *, void *);
 174         u32 tail;
 175         int ret;
 176
 177         if (qp->ibqp.srq) {
 178                 srq = to_isrq(qp->ibqp.srq);
 179                 handler = srq->ibsrq.event_handler;
 180                 rq = &srq->rq;
 181         } else {
 182                 srq = NULL;
 183                 handler = NULL;
 184                 rq = &qp->r_rq;
 185         }
 186
 187         spin_lock_irqsave(&rq->lock, flags);
 188         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
 189                 ret = 0;
 190                 goto unlock;
 191         }
 192
 193         wq = rq->wq;
 194         tail = wq->tail;
 195         /* Validate tail before using it since it is user writable. */
 196         if (tail >= rq->size)
 197                 tail = 0;
 198         do {
 199                 if (unlikely(tail == wq->head)) {
 200                         ret = 0;
 201                         goto unlock;
 202                 }
 203                 /* Make sure entry is read after head index is read. */
 204                 smp_rmb();
 205                 wqe = get_rwqe_ptr(rq, tail);
 206                 if (++tail >= rq->size)
 207                         tail = 0;
 208                 if (wr_id_only)
 209                         break;
 210                 qp->r_sge.sg_list = qp->r_sg_list;
 211         } while (!ipath_init_sge(qp, wqe, &qp->r_len, &qp->r_sge));
 212         qp->r_wr_id = wqe->wr_id;
 213         wq->tail = tail;
 214
 215         ret = 1;
 216         set_bit(IPATH_R_WRID_VALID, &qp->r_aflags);
 217         if (handler) {
 218                 u32 n;
 219
 220                 /*
 221                  * validate head pointer value and compute
 222                  * the number of remaining WQEs.
 223                  */
 224                 n = wq->head;
 225                 if (n >= rq->size)
 226                         n = 0;
 227                 if (n < tail)
 228                         n += rq->size - tail;
 229                 else
 230                         n -= tail;
 231                 if (n < srq->limit) {
 232                         struct ib_event ev;
 233
 234                         srq->limit = 0;
 235                         spin_unlock_irqrestore(&rq->lock, flags);
 236                         ev.device = qp->ibqp.device;
 237                         ev.element.srq = qp->ibqp.srq;
 238                         ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
 239                         handler(&ev, srq->ibsrq.srq_context);
 240                         goto bail;
 241                 }
 242         }
 243 unlock:
 244         spin_unlock_irqrestore(&rq->lock, flags);
 245 bail:
 246         return ret;
 247 }
 248
 249 /**
 250  * ipath_ruc_loopback - handle UC and RC lookback requests
 251  * @sqp: the sending QP
 252  *
 253  * This is called from ipath_do_send() to
 254  * forward a WQE addressed to the same HCA.
 255  * Note that although we are single threaded due to the tasklet, we still
 256  * have to protect against post_send().  We don't have to worry about
 257  * receive interrupts since this is a connected protocol and all packets
 258  * will pass through here.
 259  */
 260 static void ipath_ruc_loopback(struct ipath_qp *sqp)
 261 {
 262         struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
 263         struct ipath_qp *qp;
 264         struct ipath_swqe *wqe;
 265         struct ipath_sge *sge;
 266         unsigned long flags;
 267         struct ib_wc wc;
 268         u64 sdata;
 269         atomic64_t *maddr;
 270         enum ib_wc_status send_status;
 271
 272         /*
 273          * Note that we check the responder QP state after
 274          * checking the requester's state.
 275          */
 276         qp = ipath_lookup_qpn(&dev->qp_table, sqp->remote_qpn);
 277
 278         spin_lock_irqsave(&sqp->s_lock, flags);
 279
 280         /* Return if we are already busy processing a work request. */
 281         if ((sqp->s_flags & (IPATH_S_BUSY | IPATH_S_ANY_WAIT)) ||
 282             !(ib_ipath_state_ops[sqp->state] & IPATH_PROCESS_OR_FLUSH_SEND))
 283                 goto unlock;
 284
 285         sqp->s_flags |= IPATH_S_BUSY;
 286
 287 again:
 288         if (sqp->s_last == sqp->s_head)
 289                 goto clr_busy;
 290         wqe = get_swqe_ptr(sqp, sqp->s_last);
 291
 292         /* Return if it is not OK to start a new work reqeust. */
 293         if (!(ib_ipath_state_ops[sqp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
 294                 if (!(ib_ipath_state_ops[sqp->state] & IPATH_FLUSH_SEND))
 295                         goto clr_busy;
 296                 /* We are in the error state, flush the work request. */
 297                 send_status = IB_WC_WR_FLUSH_ERR;
 298                 goto flush_send;
 299         }
 300
 301         /*
 302          * We can rely on the entry not changing without the s_lock
 303          * being held until we update s_last.
 304          * We increment s_cur to indicate s_last is in progress.
 305          */
 306         if (sqp->s_last == sqp->s_cur) {
 307                 if (++sqp->s_cur >= sqp->s_size)
 308                         sqp->s_cur = 0;
 309         }
 310         spin_unlock_irqrestore(&sqp->s_lock, flags);
 311
 312         if (!qp || !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
 313                 dev->n_pkt_drops++;
 314                 /*
 315                  * For RC, the requester would timeout and retry so
 316                  * shortcut the timeouts and just signal too many retries.
 317                  */
 318                 if (sqp->ibqp.qp_type == IB_QPT_RC)
 319                         send_status = IB_WC_RETRY_EXC_ERR;
 320                 else
 321                         send_status = IB_WC_SUCCESS;
 322                 goto serr;
 323         }
 324
 325         memset(&wc, 0, sizeof wc);
 326         send_status = IB_WC_SUCCESS;
 327
 328         sqp->s_sge.sge = wqe->sg_list[0];
 329         sqp->s_sge.sg_list = wqe->sg_list + 1;
 330         sqp->s_sge.num_sge = wqe->wr.num_sge;
 331         sqp->s_len = wqe->length;
 332         switch (wqe->wr.opcode) {
 333         case IB_WR_SEND_WITH_IMM:
 334                 wc.wc_flags = IB_WC_WITH_IMM;
 335                 wc.ex.imm_data = wqe->wr.ex.imm_data;
 336                 /* FALLTHROUGH */
 337         case IB_WR_SEND:
 338                 if (!ipath_get_rwqe(qp, 0))
 339                         goto rnr_nak;
 340                 break;
 341
 342         case IB_WR_RDMA_WRITE_WITH_IMM:
 343                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
 344                         goto inv_err;
 345                 wc.wc_flags = IB_WC_WITH_IMM;
 346                 wc.ex.imm_data = wqe->wr.ex.imm_data;
 347                 if (!ipath_get_rwqe(qp, 1))
 348                         goto rnr_nak;
 349                 /* FALLTHROUGH */
 350         case IB_WR_RDMA_WRITE:
 351                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
 352                         goto inv_err;
 353                 if (wqe->length == 0)
 354                         break;
 355                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge, wqe->length,
 356                                             wqe->wr.wr.rdma.remote_addr,
 357                                             wqe->wr.wr.rdma.rkey,
 358                                             IB_ACCESS_REMOTE_WRITE)))
 359                         goto acc_err;
 360                 break;
 361
 362         case IB_WR_RDMA_READ:
 363                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
 364                         goto inv_err;
 365                 if (unlikely(!ipath_rkey_ok(qp, &sqp->s_sge, wqe->length,
 366                                             wqe->wr.wr.rdma.remote_addr,
 367                                             wqe->wr.wr.rdma.rkey,
 368                                             IB_ACCESS_REMOTE_READ)))
 369                         goto acc_err;
 370                 qp->r_sge.sge = wqe->sg_list[0];
 371                 qp->r_sge.sg_list = wqe->sg_list + 1;
 372                 qp->r_sge.num_sge = wqe->wr.num_sge;
 373                 break;
 374
 375         case IB_WR_ATOMIC_CMP_AND_SWP:
 376         case IB_WR_ATOMIC_FETCH_AND_ADD:
 377                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
 378                         goto inv_err;
 379                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge, sizeof(u64),
 380                                             wqe->wr.wr.atomic.remote_addr,
 381                                             wqe->wr.wr.atomic.rkey,
 382                                             IB_ACCESS_REMOTE_ATOMIC)))
 383                         goto acc_err;
 384                 /* Perform atomic OP and save result. */
 385                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
 386                 sdata = wqe->wr.wr.atomic.compare_add;
 387                 *(u64 *) sqp->s_sge.sge.vaddr =
 388                         (wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) ?
 389                         (u64) atomic64_add_return(sdata, maddr) - sdata :
 390                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
 391                                       sdata, wqe->wr.wr.atomic.swap);
 392                 goto send_comp;
 393
 394         default:
 395                 send_status = IB_WC_LOC_QP_OP_ERR;
 396                 goto serr;
 397         }
 398
 399         sge = &sqp->s_sge.sge;
 400         while (sqp->s_len) {
 401                 u32 len = sqp->s_len;
 402
 403                 if (len > sge->length)
 404                         len = sge->length;
 405                 if (len > sge->sge_length)
 406                         len = sge->sge_length;
 407                 BUG_ON(len == 0);
 408                 ipath_copy_sge(&qp->r_sge, sge->vaddr, len);
 409                 sge->vaddr += len;
 410                 sge->length -= len;
 411                 sge->sge_length -= len;
 412                 if (sge->sge_length == 0) {
 413                         if (--sqp->s_sge.num_sge)
 414                                 *sge = *sqp->s_sge.sg_list++;
 415                 } else if (sge->length == 0 && sge->mr != NULL) {
 416                         if (++sge->n >= IPATH_SEGSZ) {
 417                                 if (++sge->m >= sge->mr->mapsz)
 418                                         break;
 419                                 sge->n = 0;
 420                         }
 421                         sge->vaddr =
 422                                 sge->mr->map[sge->m]->segs[sge->n].vaddr;
 423                         sge->length =
 424                                 sge->mr->map[sge->m]->segs[sge->n].length;
 425                 }
 426                 sqp->s_len -= len;
 427         }
 428
 429         if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
 430                 goto send_comp;
 431
 432         if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM)
 433                 wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
 434         else
 435                 wc.opcode = IB_WC_RECV;
 436         wc.wr_id = qp->r_wr_id;
 437         wc.status = IB_WC_SUCCESS;
 438         wc.byte_len = wqe->length;
 439         wc.qp = &qp->ibqp;
 440         wc.src_qp = qp->remote_qpn;
 441         wc.slid = qp->remote_ah_attr.dlid;
 442         wc.sl = qp->remote_ah_attr.sl;
 443         wc.port_num = 1;
 444         /* Signal completion event if the solicited bit is set. */
 445         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 446                        wqe->wr.send_flags & IB_SEND_SOLICITED);
 447
 448 send_comp:
 449         spin_lock_irqsave(&sqp->s_lock, flags);
 450 flush_send:
 451         sqp->s_rnr_retry = sqp->s_rnr_retry_cnt;
 452         ipath_send_complete(sqp, wqe, send_status);
 453         goto again;
 454
 455 rnr_nak:
 456         /* Handle RNR NAK */
 457         if (qp->ibqp.qp_type == IB_QPT_UC)
 458                 goto send_comp;
 459         /*
 460          * Note: we don't need the s_lock held since the BUSY flag
 461          * makes this single threaded.
 462          */
 463         if (sqp->s_rnr_retry == 0) {
 464                 send_status = IB_WC_RNR_RETRY_EXC_ERR;
 465                 goto serr;
 466         }
 467         if (sqp->s_rnr_retry_cnt < 7)
 468                 sqp->s_rnr_retry--;
 469         spin_lock_irqsave(&sqp->s_lock, flags);
 470         if (!(ib_ipath_state_ops[sqp->state] & IPATH_PROCESS_RECV_OK))
 471                 goto clr_busy;
 472         sqp->s_flags |= IPATH_S_WAITING;
 473         dev->n_rnr_naks++;
 474         sqp->s_rnr_timeout = ib_ipath_rnr_table[qp->r_min_rnr_timer];
 475         ipath_insert_rnr_queue(sqp);
 476         goto clr_busy;
 477
 478 inv_err:
 479         send_status = IB_WC_REM_INV_REQ_ERR;
 480         wc.status = IB_WC_LOC_QP_OP_ERR;
 481         goto err;
 482
 483 acc_err:
 484         send_status = IB_WC_REM_ACCESS_ERR;
 485         wc.status = IB_WC_LOC_PROT_ERR;
 486 err:
 487         /* responder goes to error state */
 488         ipath_rc_error(qp, wc.status);
 489
 490 serr:
 491         spin_lock_irqsave(&sqp->s_lock, flags);
 492         ipath_send_complete(sqp, wqe, send_status);
 493         if (sqp->ibqp.qp_type == IB_QPT_RC) {
 494                 int lastwqe = ipath_error_qp(sqp, IB_WC_WR_FLUSH_ERR);
 495
 496                 sqp->s_flags &= ~IPATH_S_BUSY;
 497                 spin_unlock_irqrestore(&sqp->s_lock, flags);
 498                 if (lastwqe) {
 499                         struct ib_event ev;
 500
 501                         ev.device = sqp->ibqp.device;
 502                         ev.element.qp = &sqp->ibqp;
 503                         ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
 504                         sqp->ibqp.event_handler(&ev, sqp->ibqp.qp_context);
 505                 }
 506                 goto done;
 507         }
 508 clr_busy:
 509         sqp->s_flags &= ~IPATH_S_BUSY;
 510 unlock:
 511         spin_unlock_irqrestore(&sqp->s_lock, flags);
 512 done:
 513         if (qp && atomic_dec_and_test(&qp->refcount))
 514                 wake_up(&qp->wait);
 515 }
 516
 517 static void want_buffer(struct ipath_devdata *dd, struct ipath_qp *qp)
 518 {
 519         if (!(dd->ipath_flags & IPATH_HAS_SEND_DMA) ||
 520             qp->ibqp.qp_type == IB_QPT_SMI) {
 521                 unsigned long flags;
 522
 523                 spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
 524                 dd->ipath_sendctrl |= INFINIPATH_S_PIOINTBUFAVAIL;
 525                 ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
 526                                  dd->ipath_sendctrl);
 527                 ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
 528                 spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 529         }
 530 }
 531
 532 /**
 533  * ipath_no_bufs_available - tell the layer driver we need buffers
 534  * @qp: the QP that caused the problem
 535  * @dev: the device we ran out of buffers on
 536  *
 537  * Called when we run out of PIO buffers.
 538  * If we are now in the error state, return zero to flush the
 539  * send work request.
 540  */
 541 static int ipath_no_bufs_available(struct ipath_qp *qp,
 542                                     struct ipath_ibdev *dev)
 543 {
 544         unsigned long flags;
 545         int ret = 1;
 546
 547         /*
 548          * Note that as soon as want_buffer() is called and
 549          * possibly before it returns, ipath_ib_piobufavail()
 550          * could be called. Therefore, put QP on the piowait list before
 551          * enabling the PIO avail interrupt.
 552          */
 553         spin_lock_irqsave(&qp->s_lock, flags);
 554         if (ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK) {
 555                 dev->n_piowait++;
 556                 qp->s_flags |= IPATH_S_WAITING;
 557                 qp->s_flags &= ~IPATH_S_BUSY;
 558                 spin_lock(&dev->pending_lock);
 559                 if (list_empty(&qp->piowait))
 560                         list_add_tail(&qp->piowait, &dev->piowait);
 561                 spin_unlock(&dev->pending_lock);
 562         } else
 563                 ret = 0;
 564         spin_unlock_irqrestore(&qp->s_lock, flags);
 565         if (ret)
 566                 want_buffer(dev->dd, qp);
 567         return ret;
 568 }
 569
 570 /**
 571  * ipath_make_grh - construct a GRH header
 572  * @dev: a pointer to the ipath device
 573  * @hdr: a pointer to the GRH header being constructed
 574  * @grh: the global route address to send to
 575  * @hwords: the number of 32 bit words of header being sent
 576  * @nwords: the number of 32 bit words of data being sent
 577  *
 578  * Return the size of the header in 32 bit words.
 579  */
 580 u32 ipath_make_grh(struct ipath_ibdev *dev, struct ib_grh *hdr,
 581                    struct ib_global_route *grh, u32 hwords, u32 nwords)
 582 {
 583         hdr->version_tclass_flow =
 584                 cpu_to_be32((6 << 28) |
 585                             (grh->traffic_class << 20) |
 586                             grh->flow_label);
 587         hdr->paylen = cpu_to_be16((hwords - 2 + nwords + SIZE_OF_CRC) << 2);
 588         /* next_hdr is defined by C8-7 in ch. 8.4.1 */
 589         hdr->next_hdr = 0x1B;
 590         hdr->hop_limit = grh->hop_limit;
 591         /* The SGID is 32-bit aligned. */
 592         hdr->sgid.global.subnet_prefix = dev->gid_prefix;
 593         hdr->sgid.global.interface_id = dev->dd->ipath_guid;
 594         hdr->dgid = grh->dgid;
 595
 596         /* GRH header size in 32-bit words. */
 597         return sizeof(struct ib_grh) / sizeof(u32);
 598 }
 599
 600 void ipath_make_ruc_header(struct ipath_ibdev *dev, struct ipath_qp *qp,
 601                            struct ipath_other_headers *ohdr,
 602                            u32 bth0, u32 bth2)
 603 {
 604         u16 lrh0;
 605         u32 nwords;
 606         u32 extra_bytes;
 607
 608         /* Construct the header. */
 609         extra_bytes = -qp->s_cur_size & 3;
 610         nwords = (qp->s_cur_size + extra_bytes) >> 2;
 611         lrh0 = IPATH_LRH_BTH;
 612         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 613                 qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
 614                                                  &qp->remote_ah_attr.grh,
 615                                                  qp->s_hdrwords, nwords);
 616                 lrh0 = IPATH_LRH_GRH;
 617         }
 618         lrh0 |= qp->remote_ah_attr.sl << 4;
 619         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 620         qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 621         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
 622         qp->s_hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid |
 623                                        qp->remote_ah_attr.src_path_bits);
 624         bth0 |= ipath_get_pkey(dev->dd, qp->s_pkey_index);
 625         bth0 |= extra_bytes << 20;
 626         ohdr->bth[0] = cpu_to_be32(bth0 | (1 << 22));
 627         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 628         ohdr->bth[2] = cpu_to_be32(bth2);
 629 }
 630
 631 /**
 632  * ipath_do_send - perform a send on a QP
 633  * @data: contains a pointer to the QP
 634  *
 635  * Process entries in the send work queue until credit or queue is
 636  * exhausted.  Only allow one CPU to send a packet per QP (tasklet).
 637  * Otherwise, two threads could send packets out of order.
 638  */
 639 void ipath_do_send(unsigned long data)
 640 {
 641         struct ipath_qp *qp = (struct ipath_qp *)data;
 642         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 643         int (*make_req)(struct ipath_qp *qp);
 644         unsigned long flags;
 645
 646         if ((qp->ibqp.qp_type == IB_QPT_RC ||
 647              qp->ibqp.qp_type == IB_QPT_UC) &&
 648             qp->remote_ah_attr.dlid == dev->dd->ipath_lid) {
 649                 ipath_ruc_loopback(qp);
 650                 goto bail;
 651         }
 652
 653         if (qp->ibqp.qp_type == IB_QPT_RC)
 654                make_req = ipath_make_rc_req;
 655         else if (qp->ibqp.qp_type == IB_QPT_UC)
 656                make_req = ipath_make_uc_req;
 657         else
 658                make_req = ipath_make_ud_req;
 659
 660         spin_lock_irqsave(&qp->s_lock, flags);
 661
 662         /* Return if we are already busy processing a work request. */
 663         if ((qp->s_flags & (IPATH_S_BUSY | IPATH_S_ANY_WAIT)) ||
 664             !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_OR_FLUSH_SEND)) {
 665                 spin_unlock_irqrestore(&qp->s_lock, flags);
 666                 goto bail;
 667         }
 668
 669         qp->s_flags |= IPATH_S_BUSY;
 670
 671         spin_unlock_irqrestore(&qp->s_lock, flags);
 672
 673 again:
 674         /* Check for a constructed packet to be sent. */
 675         if (qp->s_hdrwords != 0) {
 676                 /*
 677                  * If no PIO bufs are available, return.  An interrupt will
 678                  * call ipath_ib_piobufavail() when one is available.
 679                  */
 680                 if (ipath_verbs_send(qp, &qp->s_hdr, qp->s_hdrwords,
 681                                      qp->s_cur_sge, qp->s_cur_size)) {
 682                         if (ipath_no_bufs_available(qp, dev))
 683                                 goto bail;
 684                 }
 685                 dev->n_unicast_xmit++;
 686                 /* Record that we sent the packet and s_hdr is empty. */
 687                 qp->s_hdrwords = 0;
 688         }
 689
 690         if (make_req(qp))
 691                 goto again;
 692
 693 bail:;
 694 }
 695
 696 /*
 697  * This should be called with s_lock held.
 698  */
 699 void ipath_send_complete(struct ipath_qp *qp, struct ipath_swqe *wqe,
 700                          enum ib_wc_status status)
 701 {
 702         u32 old_last, last;
 703
 704         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_OR_FLUSH_SEND))
 705                 return;
 706
 707         /* See ch. 11.2.4.1 and 10.7.3.1 */
 708         if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
 709             (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
 710             status != IB_WC_SUCCESS) {
 711                 struct ib_wc wc;
 712
 713                 memset(&wc, 0, sizeof wc);
 714                 wc.wr_id = wqe->wr.wr_id;
 715                 wc.status = status;
 716                 wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 717                 wc.qp = &qp->ibqp;
 718                 if (status == IB_WC_SUCCESS)
 719                         wc.byte_len = wqe->length;
 720                 ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc,
 721                                status != IB_WC_SUCCESS);
 722         }
 723
 724         old_last = last = qp->s_last;
 725         if (++last >= qp->s_size)
 726                 last = 0;
 727         qp->s_last = last;
 728         if (qp->s_cur == old_last)
 729                 qp->s_cur = last;
 730         if (qp->s_tail == old_last)
 731                 qp->s_tail = last;
 732         if (qp->state == IB_QPS_SQD && last == qp->s_cur)
 733                 qp->s_draining = 0;
 734 }