drivers/infiniband/hw/ipath/ipath_ruc.c

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