mthca_srq.c

Go to the documentation of this file.

/*
 * Copyright (c) 2005 Cisco Systems. 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/slab.h>
#include <linux/string.h>
#include <linux/sched.h>

#include <asm/io.h>

#include "mthca_dev.h"
#include "mthca_cmd.h"
#include "mthca_memfree.h"
#include "mthca_wqe.h"

enum {
    MTHCA_MAX_DIRECT_SRQ_SIZE = 4 * PAGE_SIZE
};

struct mthca_tavor_srq_context {
    __be64 wqe_base_ds; /* low 6 bits is descriptor size */
    __be32 state_pd;
    __be32 lkey;
    __be32 uar;
    __be16 limit_watermark;
    __be16 wqe_cnt;
    u32    reserved[2];
};

struct mthca_arbel_srq_context {
    __be32 state_logsize_srqn;
    __be32 lkey;
    __be32 db_index;
    __be32 logstride_usrpage;
    __be64 wqe_base;
    __be32 eq_pd;
    __be16 limit_watermark;
    __be16 wqe_cnt;
    u16    reserved1;
    __be16 wqe_counter;
    u32    reserved2[3];
};

static void *get_wqe(struct mthca_srq *srq, int n)
{
    if (srq->is_direct)
        return srq->queue.direct.buf + (n << srq->wqe_shift);
    else
        return srq->queue.page_list[(n << srq->wqe_shift) >> PAGE_SHIFT].buf +
            ((n << srq->wqe_shift) & (PAGE_SIZE - 1));
}

/*
 * Return a pointer to the location within a WQE that we're using as a
 * link when the WQE is in the free list.  We use the imm field
 * because in the Tavor case, posting a WQE may overwrite the next
 * segment of the previous WQE, but a receive WQE will never touch the
 * imm field.  This avoids corrupting our free list if the previous
 * WQE has already completed and been put on the free list when we
 * post the next WQE.
 */
static inline int *wqe_to_link(void *wqe)
{
    return (int *) (wqe + offsetof(struct mthca_next_seg, imm));
}

static void mthca_tavor_init_srq_context(struct mthca_dev *dev,
                     struct mthca_pd *pd,
                     struct mthca_srq *srq,
                     struct mthca_tavor_srq_context *context)
{
    memset(context, 0, sizeof *context);

    context->wqe_base_ds = cpu_to_be64(1 << (srq->wqe_shift - 4));
    context->state_pd    = cpu_to_be32(pd->pd_num);
    context->lkey        = cpu_to_be32(srq->mr.ibmr.lkey);

    if (pd->ibpd.uobject)
        context->uar =
            cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
    else
        context->uar = cpu_to_be32(dev->driver_uar.index);
}

static void mthca_arbel_init_srq_context(struct mthca_dev *dev,
                     struct mthca_pd *pd,
                     struct mthca_srq *srq,
                     struct mthca_arbel_srq_context *context)
{
    int logsize, max;

    memset(context, 0, sizeof *context);

    /*
     * Put max in a temporary variable to work around gcc bug
     * triggered by ilog2() on sparc64.
     */
    max = srq->max;
    logsize = ilog2(max);
    context->state_logsize_srqn = cpu_to_be32(logsize << 24 | srq->srqn);
    context->lkey = cpu_to_be32(srq->mr.ibmr.lkey);
    context->db_index = cpu_to_be32(srq->db_index);
    context->logstride_usrpage = cpu_to_be32((srq->wqe_shift - 4) << 29);
    if (pd->ibpd.uobject)
        context->logstride_usrpage |=
            cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
    else
        context->logstride_usrpage |= cpu_to_be32(dev->driver_uar.index);
    context->eq_pd = cpu_to_be32(MTHCA_EQ_ASYNC << 24 | pd->pd_num);
}

static void mthca_free_srq_buf(struct mthca_dev *dev, struct mthca_srq *srq)
{
    mthca_buf_free(dev, srq->max << srq->wqe_shift, &srq->queue,
               srq->is_direct, &srq->mr);
    kfree(srq->wrid);
}

static int mthca_alloc_srq_buf(struct mthca_dev *dev, struct mthca_pd *pd,
                   struct mthca_srq *srq)
{
    struct mthca_data_seg *scatter;
    void *wqe;
    int err;
    int i;

    if (pd->ibpd.uobject)
        return 0;

    srq->wrid = kmalloc(srq->max * sizeof (u64), GFP_KERNEL);
    if (!srq->wrid)
        return -ENOMEM;

    err = mthca_buf_alloc(dev, srq->max << srq->wqe_shift,
                  MTHCA_MAX_DIRECT_SRQ_SIZE,
                  &srq->queue, &srq->is_direct, pd, 1, &srq->mr);
    if (err) {
        kfree(srq->wrid);
        return err;
    }

    /*
     * Now initialize the SRQ buffer so that all of the WQEs are
     * linked into the list of free WQEs.  In addition, set the
     * scatter list L_Keys to the sentry value of 0x100.
     */
    for (i = 0; i < srq->max; ++i) {
        struct mthca_next_seg *next;

        next = wqe = get_wqe(srq, i);

        if (i < srq->max - 1) {
            *wqe_to_link(wqe) = i + 1;
            next->nda_op = htonl(((i + 1) << srq->wqe_shift) | 1);
        } else {
            *wqe_to_link(wqe) = -1;
            next->nda_op = 0;
        }

        for (scatter = wqe + sizeof (struct mthca_next_seg);
             (void *) scatter < wqe + (1 << srq->wqe_shift);
             ++scatter)
            scatter->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
    }

    srq->last = get_wqe(srq, srq->max - 1);

    return 0;
}

int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
            struct ib_srq_attr *attr, struct mthca_srq *srq)
{
    struct mthca_mailbox *mailbox;
    int ds;
    int err;

    /* Sanity check SRQ size before proceeding */
    if (attr->max_wr  > dev->limits.max_srq_wqes ||
        attr->max_sge > dev->limits.max_srq_sge)
        return -EINVAL;

    srq->max      = attr->max_wr;
    srq->max_gs   = attr->max_sge;
    srq->counter  = 0;

    if (mthca_is_memfree(dev))
        srq->max = roundup_pow_of_two(srq->max + 1);
    else
        srq->max = srq->max + 1;

    ds = max(64UL,
         roundup_pow_of_two(sizeof (struct mthca_next_seg) +
                    srq->max_gs * sizeof (struct mthca_data_seg)));

    if (!mthca_is_memfree(dev) && (ds > dev->limits.max_desc_sz))
        return -EINVAL;

    srq->wqe_shift = ilog2(ds);

    srq->srqn = mthca_alloc(&dev->srq_table.alloc);
    if (srq->srqn == -1)
        return -ENOMEM;

    if (mthca_is_memfree(dev)) {
        err = mthca_table_get(dev, dev->srq_table.table, srq->srqn);
        if (err)
            goto err_out;

        if (!pd->ibpd.uobject) {
            srq->db_index = mthca_alloc_db(dev, MTHCA_DB_TYPE_SRQ,
                               srq->srqn, &srq->db);
            if (srq->db_index < 0) {
                err = -ENOMEM;
                goto err_out_icm;
            }
        }
    }

    mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
    if (IS_ERR(mailbox)) {
        err = PTR_ERR(mailbox);
        goto err_out_db;
    }

    err = mthca_alloc_srq_buf(dev, pd, srq);
    if (err)
        goto err_out_mailbox;

    spin_lock_init(&srq->lock);
    srq->refcount = 1;
    init_waitqueue_head(&srq->wait);
    mutex_init(&srq->mutex);

    if (mthca_is_memfree(dev))
        mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
    else
        mthca_tavor_init_srq_context(dev, pd, srq, mailbox->buf);

    err = mthca_SW2HW_SRQ(dev, mailbox, srq->srqn);

    if (err) {
        mthca_warn(dev, "SW2HW_SRQ failed (%d)\n", err);
        goto err_out_free_buf;
    }

    spin_lock_irq(&dev->srq_table.lock);
    if (mthca_array_set(&dev->srq_table.srq,
                srq->srqn & (dev->limits.num_srqs - 1),
                srq)) {
        spin_unlock_irq(&dev->srq_table.lock);
        goto err_out_free_srq;
    }
    spin_unlock_irq(&dev->srq_table.lock);

    mthca_free_mailbox(dev, mailbox);

    srq->first_free = 0;
    srq->last_free  = srq->max - 1;

    attr->max_wr    = srq->max - 1;
    attr->max_sge   = srq->max_gs;

    return 0;

err_out_free_srq:
    err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn);
    if (err)
        mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);

err_out_free_buf:
    if (!pd->ibpd.uobject)
        mthca_free_srq_buf(dev, srq);

err_out_mailbox:
    mthca_free_mailbox(dev, mailbox);

err_out_db:
    if (!pd->ibpd.uobject && mthca_is_memfree(dev))
        mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);

err_out_icm:
    mthca_table_put(dev, dev->srq_table.table, srq->srqn);

err_out:
    mthca_free(&dev->srq_table.alloc, srq->srqn);

    return err;
}

static inline int get_srq_refcount(struct mthca_dev *dev, struct mthca_srq *srq)
{
    int c;

    spin_lock_irq(&dev->srq_table.lock);
    c = srq->refcount;
    spin_unlock_irq(&dev->srq_table.lock);

    return c;
}

void mthca_free_srq(struct mthca_dev *dev, struct mthca_srq *srq)
{
    struct mthca_mailbox *mailbox;
    int err;

    mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
    if (IS_ERR(mailbox)) {
        mthca_warn(dev, "No memory for mailbox to free SRQ.\n");
        return;
    }

    err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn);
    if (err)
        mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);

    spin_lock_irq(&dev->srq_table.lock);
    mthca_array_clear(&dev->srq_table.srq,
              srq->srqn & (dev->limits.num_srqs - 1));
    --srq->refcount;
    spin_unlock_irq(&dev->srq_table.lock);

    wait_event(srq->wait, !get_srq_refcount(dev, srq));

    if (!srq->ibsrq.uobject) {
        mthca_free_srq_buf(dev, srq);
        if (mthca_is_memfree(dev))
            mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
    }

    mthca_table_put(dev, dev->srq_table.table, srq->srqn);
    mthca_free(&dev->srq_table.alloc, srq->srqn);
    mthca_free_mailbox(dev, mailbox);
}

int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
             enum ib_srq_attr_mask attr_mask, struct ib_udata *udata)
{
    struct mthca_dev *dev = to_mdev(ibsrq->device);
    struct mthca_srq *srq = to_msrq(ibsrq);
    int ret = 0;

    /* We don't support resizing SRQs (yet?) */
    if (attr_mask & IB_SRQ_MAX_WR)
        return -EINVAL;

    if (attr_mask & IB_SRQ_LIMIT) {
        u32 max_wr = mthca_is_memfree(dev) ? srq->max - 1 : srq->max;
        if (attr->srq_limit > max_wr)
            return -EINVAL;

        mutex_lock(&srq->mutex);
        ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit);
        mutex_unlock(&srq->mutex);
    }

    return ret;
}

int mthca_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
{
    struct mthca_dev *dev = to_mdev(ibsrq->device);
    struct mthca_srq *srq = to_msrq(ibsrq);
    struct mthca_mailbox *mailbox;
    struct mthca_arbel_srq_context *arbel_ctx;
    struct mthca_tavor_srq_context *tavor_ctx;
    int err;

    mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
    if (IS_ERR(mailbox))
        return PTR_ERR(mailbox);

    err = mthca_QUERY_SRQ(dev, srq->srqn, mailbox);
    if (err)
        goto out;

    if (mthca_is_memfree(dev)) {
        arbel_ctx = mailbox->buf;
        srq_attr->srq_limit = be16_to_cpu(arbel_ctx->limit_watermark);
    } else {
        tavor_ctx = mailbox->buf;
        srq_attr->srq_limit = be16_to_cpu(tavor_ctx->limit_watermark);
    }

    srq_attr->max_wr  = srq->max - 1;
    srq_attr->max_sge = srq->max_gs;

out:
    mthca_free_mailbox(dev, mailbox);

    return err;
}

void mthca_srq_event(struct mthca_dev *dev, u32 srqn,
             enum ib_event_type event_type)
{
    struct mthca_srq *srq;
    struct ib_event event;

    spin_lock(&dev->srq_table.lock);
    srq = mthca_array_get(&dev->srq_table.srq, srqn & (dev->limits.num_srqs - 1));
    if (srq)
        ++srq->refcount;
    spin_unlock(&dev->srq_table.lock);

    if (!srq) {
        mthca_warn(dev, "Async event for bogus SRQ %08x\n", srqn);
        return;
    }

    if (!srq->ibsrq.event_handler)
        goto out;

    event.device      = &dev->ib_dev;
    event.event       = event_type;
    event.element.srq = &srq->ibsrq;
    srq->ibsrq.event_handler(&event, srq->ibsrq.srq_context);

out:
    spin_lock(&dev->srq_table.lock);
    if (!--srq->refcount)
        wake_up(&srq->wait);
    spin_unlock(&dev->srq_table.lock);
}

/*
 * This function must be called with IRQs disabled.
 */
void mthca_free_srq_wqe(struct mthca_srq *srq, u32 wqe_addr)
{
    int ind;
    struct mthca_next_seg *last_free;

    ind = wqe_addr >> srq->wqe_shift;

    spin_lock(&srq->lock);

    last_free = get_wqe(srq, srq->last_free);
    *wqe_to_link(last_free) = ind;
    last_free->nda_op = htonl((ind << srq->wqe_shift) | 1);
    *wqe_to_link(get_wqe(srq, ind)) = -1;
    srq->last_free = ind;

    spin_unlock(&srq->lock);
}

int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
                  struct ib_recv_wr **bad_wr)
{
    struct mthca_dev *dev = to_mdev(ibsrq->device);
    struct mthca_srq *srq = to_msrq(ibsrq);
    unsigned long flags;
    int err = 0;
    int first_ind;
    int ind;
    int next_ind;
    int nreq;
    int i;
    void *wqe;
    void *prev_wqe;

    spin_lock_irqsave(&srq->lock, flags);

    first_ind = srq->first_free;

    for (nreq = 0; wr; wr = wr->next) {
        ind       = srq->first_free;
        wqe       = get_wqe(srq, ind);
        next_ind  = *wqe_to_link(wqe);

        if (unlikely(next_ind < 0)) {
            mthca_err(dev, "SRQ %06x full\n", srq->srqn);
            err = -ENOMEM;
            *bad_wr = wr;
            break;
        }

        prev_wqe  = srq->last;
        srq->last = wqe;

        ((struct mthca_next_seg *) wqe)->ee_nds = 0;
        /* flags field will always remain 0 */

        wqe += sizeof (struct mthca_next_seg);

        if (unlikely(wr->num_sge > srq->max_gs)) {
            err = -EINVAL;
            *bad_wr = wr;
            srq->last = prev_wqe;
            break;
        }

        for (i = 0; i < wr->num_sge; ++i) {
            mthca_set_data_seg(wqe, wr->sg_list + i);
            wqe += sizeof (struct mthca_data_seg);
        }

        if (i < srq->max_gs)
            mthca_set_data_seg_inval(wqe);

        ((struct mthca_next_seg *) prev_wqe)->ee_nds =
            cpu_to_be32(MTHCA_NEXT_DBD);

        srq->wrid[ind]  = wr->wr_id;
        srq->first_free = next_ind;

        ++nreq;
        if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
            nreq = 0;

            /*
             * Make sure that descriptors are written
             * before doorbell is rung.
             */
            wmb();

            mthca_write64(first_ind << srq->wqe_shift, srq->srqn << 8,
                      dev->kar + MTHCA_RECEIVE_DOORBELL,
                      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));

            first_ind = srq->first_free;
        }
    }

    if (likely(nreq)) {
        /*
         * Make sure that descriptors are written before
         * doorbell is rung.
         */
        wmb();

        mthca_write64(first_ind << srq->wqe_shift, (srq->srqn << 8) | nreq,
                  dev->kar + MTHCA_RECEIVE_DOORBELL,
                  MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
    }

    /*
     * Make sure doorbells don't leak out of SRQ spinlock and
     * reach the HCA out of order:
     */
    mmiowb();

    spin_unlock_irqrestore(&srq->lock, flags);
    return err;
}

int mthca_arbel_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
                  struct ib_recv_wr **bad_wr)
{
    struct mthca_dev *dev = to_mdev(ibsrq->device);
    struct mthca_srq *srq = to_msrq(ibsrq);
    unsigned long flags;
    int err = 0;
    int ind;
    int next_ind;
    int nreq;
    int i;
    void *wqe;

    spin_lock_irqsave(&srq->lock, flags);

    for (nreq = 0; wr; ++nreq, wr = wr->next) {
        ind       = srq->first_free;
        wqe       = get_wqe(srq, ind);
        next_ind  = *wqe_to_link(wqe);

        if (unlikely(next_ind < 0)) {
            mthca_err(dev, "SRQ %06x full\n", srq->srqn);
            err = -ENOMEM;
            *bad_wr = wr;
            break;
        }

        ((struct mthca_next_seg *) wqe)->ee_nds = 0;
        /* flags field will always remain 0 */

        wqe += sizeof (struct mthca_next_seg);

        if (unlikely(wr->num_sge > srq->max_gs)) {
            err = -EINVAL;
            *bad_wr = wr;
            break;
        }

        for (i = 0; i < wr->num_sge; ++i) {
            mthca_set_data_seg(wqe, wr->sg_list + i);
            wqe += sizeof (struct mthca_data_seg);
        }

        if (i < srq->max_gs)
            mthca_set_data_seg_inval(wqe);

        srq->wrid[ind]  = wr->wr_id;
        srq->first_free = next_ind;
    }

    if (likely(nreq)) {
        srq->counter += nreq;

        /*
         * Make sure that descriptors are written before
         * we write doorbell record.
         */
        wmb();
        *srq->db = cpu_to_be32(srq->counter);
    }

    spin_unlock_irqrestore(&srq->lock, flags);
    return err;
}

int mthca_max_srq_sge(struct mthca_dev *dev)
{
    if (mthca_is_memfree(dev))
        return dev->limits.max_sg;

    /*
     * SRQ allocations are based on powers of 2 for Tavor,
     * (although they only need to be multiples of 16 bytes).
     *
     * Therefore, we need to base the max number of sg entries on
     * the largest power of 2 descriptor size that is <= to the
     * actual max WQE descriptor size, rather than return the
     * max_sg value given by the firmware (which is based on WQE
     * sizes as multiples of 16, not powers of 2).
     *
     * If SRQ implementation is changed for Tavor to be based on
     * multiples of 16, the calculation below can be deleted and
     * the FW max_sg value returned.
     */
    return min_t(int, dev->limits.max_sg,
             ((1 << (fls(dev->limits.max_desc_sz) - 1)) -
              sizeof (struct mthca_next_seg)) /
             sizeof (struct mthca_data_seg));
}

int mthca_init_srq_table(struct mthca_dev *dev)
{
    int err;

    if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
        return 0;

    spin_lock_init(&dev->srq_table.lock);

    err = mthca_alloc_init(&dev->srq_table.alloc,
                   dev->limits.num_srqs,
                   dev->limits.num_srqs - 1,
                   dev->limits.reserved_srqs);
    if (err)
        return err;

    err = mthca_array_init(&dev->srq_table.srq,
                   dev->limits.num_srqs);
    if (err)
        mthca_alloc_cleanup(&dev->srq_table.alloc);

    return err;
}

void mthca_cleanup_srq_table(struct mthca_dev *dev)
{
    if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
        return;

    mthca_array_cleanup(&dev->srq_table.srq, dev->limits.num_srqs);
    mthca_alloc_cleanup(&dev->srq_table.alloc);
}