diff options
Diffstat (limited to 'drivers/infiniband/sw/rdmavt/rc.c')
| -rw-r--r-- | drivers/infiniband/sw/rdmavt/rc.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/infiniband/sw/rdmavt/rc.c b/drivers/infiniband/sw/rdmavt/rc.c new file mode 100644 index 000000000000..6131cc558bdb --- /dev/null +++ b/drivers/infiniband/sw/rdmavt/rc.c @@ -0,0 +1,189 @@ +/* + * Copyright(c) 2016 Intel Corporation. + * + * This file is provided under a dual BSD/GPLv2 license. When using or + * redistributing this file, you may do so under either license. + * + * GPL LICENSE SUMMARY + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * BSD LICENSE + * + * 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. + * - Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +#include <rdma/rdma_vt.h> +#include <rdma/ib_hdrs.h> + +/* + * Convert the AETH credit code into the number of credits. + */ +static const u16 credit_table[31] = { + 0, /* 0 */ + 1, /* 1 */ + 2, /* 2 */ + 3, /* 3 */ + 4, /* 4 */ + 6, /* 5 */ + 8, /* 6 */ + 12, /* 7 */ + 16, /* 8 */ + 24, /* 9 */ + 32, /* A */ + 48, /* B */ + 64, /* C */ + 96, /* D */ + 128, /* E */ + 192, /* F */ + 256, /* 10 */ + 384, /* 11 */ + 512, /* 12 */ + 768, /* 13 */ + 1024, /* 14 */ + 1536, /* 15 */ + 2048, /* 16 */ + 3072, /* 17 */ + 4096, /* 18 */ + 6144, /* 19 */ + 8192, /* 1A */ + 12288, /* 1B */ + 16384, /* 1C */ + 24576, /* 1D */ + 32768 /* 1E */ +}; + +/** + * rvt_compute_aeth - compute the AETH (syndrome + MSN) + * @qp: the queue pair to compute the AETH for + * + * Returns the AETH. + */ +__be32 rvt_compute_aeth(struct rvt_qp *qp) +{ + u32 aeth = qp->r_msn & IB_MSN_MASK; + + if (qp->ibqp.srq) { + /* + * Shared receive queues don't generate credits. + * Set the credit field to the invalid value. + */ + aeth |= IB_AETH_CREDIT_INVAL << IB_AETH_CREDIT_SHIFT; + } else { + u32 min, max, x; + u32 credits; + struct rvt_rwq *wq = qp->r_rq.wq; + u32 head; + u32 tail; + + /* sanity check pointers before trusting them */ + head = wq->head; + if (head >= qp->r_rq.size) + head = 0; + tail = wq->tail; + if (tail >= qp->r_rq.size) + tail = 0; + /* + * Compute the number of credits available (RWQEs). + * There is a small chance that the pair of reads are + * not atomic, which is OK, since the fuzziness is + * resolved as further ACKs go out. + */ + credits = head - tail; + if ((int)credits < 0) + credits += qp->r_rq.size; + /* + * Binary search the credit table to find the code to + * use. + */ + min = 0; + max = 31; + for (;;) { + x = (min + max) / 2; + if (credit_table[x] == credits) + break; + if (credit_table[x] > credits) { + max = x; + } else { + if (min == x) + break; + min = x; + } + } + aeth |= x << IB_AETH_CREDIT_SHIFT; + } + return cpu_to_be32(aeth); +} +EXPORT_SYMBOL(rvt_compute_aeth); + +/** + * rvt_get_credit - flush the send work queue of a QP + * @qp: the qp who's send work queue to flush + * @aeth: the Acknowledge Extended Transport Header + * + * The QP s_lock should be held. + */ +void rvt_get_credit(struct rvt_qp *qp, u32 aeth) +{ + struct rvt_dev_info *rdi = ib_to_rvt(qp->ibqp.device); + u32 credit = (aeth >> IB_AETH_CREDIT_SHIFT) & IB_AETH_CREDIT_MASK; + + lockdep_assert_held(&qp->s_lock); + /* + * If the credit is invalid, we can send + * as many packets as we like. Otherwise, we have to + * honor the credit field. + */ + if (credit == IB_AETH_CREDIT_INVAL) { + if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) { + qp->s_flags |= RVT_S_UNLIMITED_CREDIT; + if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) { + qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT; + rdi->driver_f.schedule_send(qp); + } + } + } else if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) { + /* Compute new LSN (i.e., MSN + credit) */ + credit = (aeth + credit_table[credit]) & IB_MSN_MASK; + if (rvt_cmp_msn(credit, qp->s_lsn) > 0) { + qp->s_lsn = credit; + if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) { + qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT; + rdi->driver_f.schedule_send(qp); + } + } + } +} +EXPORT_SYMBOL(rvt_get_credit); |