fca/oce/oce_tx.c

	oce_tx.c revision 0dc2366f7b9f9f36e10909b1e95edbf2a261c2ac
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Emulex.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Source file containing the implementation of the Transmit
 * Path
 */

#include <oce_impl.h>

static void oce_free_wqed(struct oce_wq *wq,  oce_wqe_desc_t *wqed);
static int oce_map_wqe(struct oce_wq *wq, oce_wqe_desc_t *wqed,
    mblk_t *mp);
static int oce_bcopy_wqe(struct oce_wq *wq, oce_wqe_desc_t *wqed, mblk_t *mp,
    uint32_t pkt_len);
static void oce_wqb_dtor(struct oce_wq *wq, oce_wq_bdesc_t *wqbd);
static int oce_wqb_ctor(oce_wq_bdesc_t *wqbd, struct oce_wq *wq,
    size_t size, int flags);
static oce_wq_bdesc_t *oce_wqb_alloc(struct oce_wq *wq);
static void oce_wqb_free(struct oce_wq *wq, oce_wq_bdesc_t *wqbd);

static void oce_wqmd_free(struct oce_wq *wq, oce_wqe_desc_t *wqed);
static void oce_wqm_free(struct oce_wq *wq, oce_wq_mdesc_t *wqmd);
static inline oce_wq_mdesc_t *oce_wqm_alloc(struct oce_wq *wq);
static int oce_wqm_ctor(oce_wq_mdesc_t *wqmd, struct oce_wq *wq);
static void oce_wqm_dtor(struct oce_wq *wq, oce_wq_mdesc_t *wqmd);
static void oce_fill_ring_descs(struct oce_wq *wq, oce_wqe_desc_t *wqed);
static void oce_remove_vtag(mblk_t *mp);
static void oce_insert_vtag(mblk_t  *mp, uint16_t vlan_tag);
static inline int oce_process_tx_compl(struct oce_wq *wq, boolean_t rearm);


static ddi_dma_attr_t tx_map_dma_attr = {
    DMA_ATTR_V0,            /* version number */
    0x0000000000000000ull,  /* low address */
    0xFFFFFFFFFFFFFFFFull,  /* high address */
    0x0000000000010000ull,  /* dma counter max */
    OCE_TXMAP_ALIGN,    /* alignment */
    0x7FF,          /* burst sizes */
    0x00000001,     /* minimum transfer size */
    0x00000000FFFFFFFFull,  /* maximum transfer size */
    0xFFFFFFFFFFFFFFFFull,  /* maximum segment size */
    OCE_MAX_TXDMA_COOKIES,  /* scatter/gather list length */
    0x00000001,     /* granularity */
    0           /* DMA flags */
};

/*
 * WQ map handle destructor
 *
 * wq - Pointer to WQ structure
 * wqmd - pointer to WQE mapping handle descriptor
 *
 * return none
 */

static void
oce_wqm_dtor(struct oce_wq *wq, oce_wq_mdesc_t *wqmd)
{
    _NOTE(ARGUNUSED(wq));
    /* Free the DMA handle */
    if (wqmd->dma_handle != NULL)
        (void) ddi_dma_free_handle(&(wqmd->dma_handle));
    wqmd->dma_handle = NULL;
} /* oce_wqm_dtor */

/*
 * WQ map handles contructor
 *
 * wqmd - pointer to WQE mapping handle descriptor
 * wq - Pointer to WQ structure
 *
 * return DDI_SUCCESS=>success, DDI_FAILURE=>error
 */
static int
oce_wqm_ctor(oce_wq_mdesc_t *wqmd, struct oce_wq *wq)
{
    struct oce_dev *dev;
    int ret;

    dev = wq->parent;
    /* Allocate DMA handle */
    ret = ddi_dma_alloc_handle(dev->dip, &tx_map_dma_attr,
        KM_SLEEP, NULL, &wqmd->dma_handle);

    return (ret);
} /* oce_wqm_ctor */

/*
 * function to create WQ mapping handles cache
 *
 * wq - pointer to WQ structure
 *
 * return DDI_SUCCESS=>success, DDI_FAILURE=>error
 */
int
oce_wqm_cache_create(struct oce_wq *wq)
{
    struct oce_dev *dev = wq->parent;
    int size;
    int cnt;
    int ret;

    size = wq->cfg.nhdl * sizeof (oce_wq_mdesc_t);
    wq->wq_mdesc_array = kmem_zalloc(size, KM_SLEEP);

    /* Create the free buffer list */
    OCE_LIST_CREATE(&wq->wq_mdesc_list, DDI_INTR_PRI(dev->intr_pri));

    for (cnt = 0; cnt < wq->cfg.nhdl; cnt++) {
        ret = oce_wqm_ctor(&wq->wq_mdesc_array[cnt], wq);
        if (ret != DDI_SUCCESS) {
            goto wqm_fail;
        }
        OCE_LIST_INSERT_TAIL(&wq->wq_mdesc_list,
            &wq->wq_mdesc_array[cnt]);
    }
    return (DDI_SUCCESS);

wqm_fail:
    oce_wqm_cache_destroy(wq);
    return (DDI_FAILURE);
}

/*
 * function to destroy WQ mapping handles cache
 *
 * wq - pointer to WQ structure
 *
 * return none
 */
void
oce_wqm_cache_destroy(struct oce_wq *wq)
{
    oce_wq_mdesc_t *wqmd;

    while ((wqmd = OCE_LIST_REM_HEAD(&wq->wq_mdesc_list)) != NULL) {
        oce_wqm_dtor(wq, wqmd);
    }

    kmem_free(wq->wq_mdesc_array,
        wq->cfg.nhdl * sizeof (oce_wq_mdesc_t));

    OCE_LIST_DESTROY(&wq->wq_mdesc_list);
}

/*
 * function to create  WQ buffer cache
 *
 * wq - pointer to WQ structure
 * buf_size - size of the buffer
 *
 * return DDI_SUCCESS=>success, DDI_FAILURE=>error
 */
int
oce_wqb_cache_create(struct oce_wq *wq, size_t buf_size)
{
    struct oce_dev *dev = wq->parent;
    int size;
    int cnt;
    int ret;

    size = wq->cfg.nbufs * sizeof (oce_wq_bdesc_t);
    wq->wq_bdesc_array = kmem_zalloc(size, KM_SLEEP);

    /* Create the free buffer list */
    OCE_LIST_CREATE(&wq->wq_buf_list, DDI_INTR_PRI(dev->intr_pri));

    for (cnt = 0; cnt <  wq->cfg.nbufs; cnt++) {
        ret = oce_wqb_ctor(&wq->wq_bdesc_array[cnt],
            wq, buf_size, DDI_DMA_STREAMING);
        if (ret != DDI_SUCCESS) {
            goto wqb_fail;
        }
        OCE_LIST_INSERT_TAIL(&wq->wq_buf_list,
            &wq->wq_bdesc_array[cnt]);
    }
    return (DDI_SUCCESS);

wqb_fail:
    oce_wqb_cache_destroy(wq);
    return (DDI_FAILURE);
}

/*
 * function to destroy WQ buffer cache
 *
 * wq - pointer to WQ structure
 *
 * return none
 */
void
oce_wqb_cache_destroy(struct oce_wq *wq)
{
    oce_wq_bdesc_t *wqbd;
    while ((wqbd = OCE_LIST_REM_HEAD(&wq->wq_buf_list)) != NULL) {
        oce_wqb_dtor(wq, wqbd);
    }
    kmem_free(wq->wq_bdesc_array,
        wq->cfg.nbufs * sizeof (oce_wq_bdesc_t));
    OCE_LIST_DESTROY(&wq->wq_buf_list);
}

/*
 * WQ buffer constructor
 *
 * wqbd - pointer to WQ buffer descriptor
 * wq - pointer to WQ structure
 * size - size of the buffer
 * flags - KM_SLEEP or KM_NOSLEEP
 *
 * return DDI_SUCCESS=>success, DDI_FAILURE=>error
 */
static int
oce_wqb_ctor(oce_wq_bdesc_t *wqbd, struct oce_wq *wq, size_t size, int flags)
{
    struct oce_dev *dev;
    dev = wq->parent;
    wqbd->wqb = oce_alloc_dma_buffer(dev, size, flags);
    if (wqbd->wqb == NULL) {
        return (DDI_FAILURE);
    }
    wqbd->frag_addr.dw.addr_lo = ADDR_LO(wqbd->wqb->addr);
    wqbd->frag_addr.dw.addr_hi = ADDR_HI(wqbd->wqb->addr);
    return (DDI_SUCCESS);
}

/*
 * WQ buffer destructor
 *
 * wq - pointer to WQ structure
 * wqbd - pointer to WQ buffer descriptor
 *
 * return none
 */
static void
oce_wqb_dtor(struct oce_wq *wq, oce_wq_bdesc_t *wqbd)
{
    oce_free_dma_buffer(wq->parent, wqbd->wqb);
}

/*
 * function to alloc   WQE buffer descriptor
 *
 * wq - pointer to WQ structure
 *
 * return pointer to WQE buffer descriptor
 */
static inline oce_wq_bdesc_t *
oce_wqb_alloc(struct oce_wq *wq)
{
    oce_wq_bdesc_t *wqbd;
    wqbd = OCE_LIST_REM_HEAD(&wq->wq_buf_list);
    return (wqbd);
}

/*
 * function to free   WQE buffer descriptor
 *
 * wq - pointer to WQ structure
 * wqbd - pointer to WQ buffer descriptor
 *
 * return none
 */
static inline void
oce_wqb_free(struct oce_wq *wq, oce_wq_bdesc_t *wqbd)
{
    OCE_LIST_INSERT_TAIL(&wq->wq_buf_list, wqbd);
} /* oce_wqb_free */

/*
 * function to allocate   WQE mapping descriptor
 *
 * wq - pointer to WQ structure
 *
 * return pointer to WQE mapping descriptor
 */
static inline oce_wq_mdesc_t *
oce_wqm_alloc(struct oce_wq *wq)
{
    oce_wq_mdesc_t *wqmd;
    wqmd = OCE_LIST_REM_HEAD(&wq->wq_mdesc_list);
    return (wqmd);

} /* oce_wqm_alloc */

/*
 * function to insert   WQE mapping descriptor to the list
 *
 * wq - pointer to WQ structure
 * wqmd - Pointer to WQ mapping descriptor
 *
 * return none
 */
static inline void
oce_wqm_free(struct oce_wq *wq, oce_wq_mdesc_t *wqmd)
{
    OCE_LIST_INSERT_TAIL(&wq->wq_mdesc_list, wqmd);
}

/*
 * function to free  WQE mapping descriptor
 *
 * wq - pointer to WQ structure
 * wqmd - Pointer to WQ mapping descriptor
 *
 * return none
 */
static void
oce_wqmd_free(struct oce_wq *wq, oce_wqe_desc_t *wqed)
{
    int ndesc;
    oce_wq_mdesc_t *wqmd;

    if (wqed == NULL) {
        return;
    }
    for (ndesc = 0; ndesc < wqed->nhdl; ndesc++) {
        wqmd = wqed->hdesc[ndesc].hdl;
        (void) ddi_dma_unbind_handle(wqmd->dma_handle);
        oce_wqm_free(wq, wqmd);
    }
}

/*
 * WQED kmem_cache constructor
 *
 * buf - pointer to WQE descriptor
 *
 * return DDI_SUCCESS
 */
int
oce_wqe_desc_ctor(void *buf, void *arg, int kmflags)
{
    oce_wqe_desc_t *wqed = (oce_wqe_desc_t *)buf;

    _NOTE(ARGUNUSED(arg));
    _NOTE(ARGUNUSED(kmflags));

    bzero(wqed, sizeof (oce_wqe_desc_t));
    return (DDI_SUCCESS);
}

/*
 * WQED kmem_cache destructor
 *
 * buf - pointer to WQE descriptor
 *
 * return none
 */
void
oce_wqe_desc_dtor(void *buf, void *arg)
{
    _NOTE(ARGUNUSED(buf));
    _NOTE(ARGUNUSED(arg));
}

/*
 * function to choose a WQ given a mblk depending on priority, flowID etc.
 *
 * dev - software handle to device
 * pkt - the mblk to send
 *
 * return pointer to the WQ selected
 */
struct oce_wq *
oce_get_wq(struct oce_dev *dev, mblk_t *pkt)
{
    _NOTE(ARGUNUSED(pkt));
    /* for the time being hardcode */
    return (dev->wq[0]);
} /* oce_get_wq */

/*
 * function to populate the single WQE
 *
 * wq - pointer to wq
 * wqed - pointer to WQ entry  descriptor
 *
 * return none
 */
#pragma inline(oce_fill_ring_descs)
static void
oce_fill_ring_descs(struct oce_wq *wq, oce_wqe_desc_t *wqed)
{

    struct oce_nic_frag_wqe *wqe;
    int i;
    /* Copy the precreate WQE descs to the ring desc */
    for (i = 0; i < wqed->wqe_cnt; i++) {
        wqe = RING_GET_PRODUCER_ITEM_VA(wq->ring,
            struct oce_nic_frag_wqe);

        bcopy(&wqed->frag[i], wqe, NIC_WQE_SIZE);
        RING_PUT(wq->ring, 1);
    }
} /* oce_fill_ring_descs */

/*
 * function to copy the packet to preallocated Tx buffer
 *
 * wq - pointer to WQ
 * wqed - Pointer to WQE descriptor
 * mp - Pointer to packet chain
 * pktlen - Size of the packet
 *
 * return 0=>success, error code otherwise
 */
static int
oce_bcopy_wqe(struct oce_wq *wq, oce_wqe_desc_t *wqed, mblk_t *mp,
    uint32_t pkt_len)
{
    oce_wq_bdesc_t *wqbd;
    caddr_t buf_va;
    struct oce_dev *dev = wq->parent;

    wqbd = oce_wqb_alloc(wq);
    if (wqbd == NULL) {
        atomic_inc_32(&dev->tx_noxmtbuf);
        oce_log(dev, CE_WARN, MOD_TX, "%s",
            "wqb pool empty");
        return (ENOMEM);
    }

    /* create a fragment wqe for the packet */
    wqed->frag[1].u0.s.frag_pa_hi = wqbd->frag_addr.dw.addr_hi;
    wqed->frag[1].u0.s.frag_pa_lo = wqbd->frag_addr.dw.addr_lo;
    buf_va = DBUF_VA(wqbd->wqb);

    /* copy pkt into buffer */
    for (; mp != NULL; mp = mp->b_cont) {
        bcopy(mp->b_rptr, buf_va, MBLKL(mp));
        buf_va += MBLKL(mp);
    }

    wqed->frag[1].u0.s.frag_len   =  pkt_len;
    wqed->hdesc[0].hdl = (void *)(wqbd);

    (void) ddi_dma_sync(DBUF_DHDL(wqbd->wqb), 0, pkt_len,
        DDI_DMA_SYNC_FORDEV);

    if (oce_fm_check_dma_handle(dev, DBUF_DHDL(wqbd->wqb))) {
        ddi_fm_service_impact(dev->dip, DDI_SERVICE_DEGRADED);
        /* Free the buffer */
        oce_wqb_free(wq, wqbd);
        return (EIO);
    }
    wqed->frag_cnt = 2;
    wqed->nhdl = 1;
    wqed->type = COPY_WQE;
    return (0);
} /* oce_bcopy_wqe */

/*
 * function to copy the packet or dma map on the fly depending on size
 *
 * wq - pointer to WQ
 * wqed - Pointer to WQE descriptor
 * mp - Pointer to packet chain
 *
 * return DDI_SUCCESS=>success, DDI_FAILURE=>error
 */
static  int
oce_map_wqe(struct oce_wq *wq, oce_wqe_desc_t *wqed, mblk_t *mp)
{
    ddi_dma_cookie_t cookie;
    oce_wq_mdesc_t *wqmd;
    int32_t nfrag = 1;
    uint32_t ncookies;
    int ret;
    uint32_t len;
    struct oce_dev *dev = wq->parent;

    wqed->nhdl = 0;
    wqed->mp = mp;

    for (; mp != NULL; mp = mp->b_cont) {
        len = MBLKL(mp);
        if (len == 0) {
            oce_log(dev, CE_NOTE, MOD_TX, "%s",
                "Zero len MBLK ");
            continue;
        }

        wqmd = oce_wqm_alloc(wq);
        if (wqmd == NULL) {
            oce_log(dev, CE_WARN, MOD_TX, "%s",
                "wqm pool empty");
            ret = ENOMEM;
            goto map_fail;
        }

        ret = ddi_dma_addr_bind_handle(wqmd->dma_handle,
            (struct as *)0, (caddr_t)mp->b_rptr,
            len, DDI_DMA_WRITE | DDI_DMA_STREAMING,
            DDI_DMA_DONTWAIT, NULL, &cookie, &ncookies);
        if (ret != DDI_DMA_MAPPED) {
            oce_log(dev, CE_WARN, MOD_TX, "%s",
                "Failed to Map SGL");
            /* free the last one */
            oce_wqm_free(wq, wqmd);
            goto map_fail;
        }

        do {
            wqed->frag[nfrag].u0.s.frag_pa_hi =
                ADDR_HI(cookie.dmac_laddress);
            wqed->frag[nfrag].u0.s.frag_pa_lo =
                ADDR_LO(cookie.dmac_laddress);
            wqed->frag[nfrag].u0.s.frag_len =
                (uint32_t)cookie.dmac_size;
            nfrag++;
            if (--ncookies > 0)
                ddi_dma_nextcookie(wqmd->dma_handle,
                    &cookie);
            else break;
        } while (ncookies > 0);

        wqed->hdesc[wqed->nhdl].hdl = (void *)wqmd;
        wqed->nhdl++;
    }
    wqed->frag_cnt = nfrag;
    wqed->type = MAPPED_WQE;
    return (0);

map_fail:
    wqed->mp = NULL;
    oce_wqmd_free(wq, wqed);
    return (ret);
} /* oce_map_wqe */

static inline int
oce_process_tx_compl(struct oce_wq *wq, boolean_t rearm)
{
    struct oce_nic_tx_cqe *cqe;
    uint16_t num_cqe = 0;
    struct oce_cq *cq;
    oce_wqe_desc_t *wqed;
    int wqe_freed = 0;
    struct oce_dev *dev;

    cq  = wq->cq;
    dev = wq->parent;
    mutex_enter(&wq->txc_lock);
    cqe = RING_GET_CONSUMER_ITEM_VA(cq->ring, struct oce_nic_tx_cqe);
    while (WQ_CQE_VALID(cqe)) {

        DW_SWAP(u32ptr(cqe), sizeof (struct oce_nic_tx_cqe));

        /* update stats */
        if (cqe->u0.s.status != 0) {
            atomic_inc_32(&dev->tx_errors);
        }

        /* complete the WQEs */
        wqed = OCE_LIST_REM_HEAD(&wq->wqe_desc_list);

        wqe_freed = wqed->wqe_cnt;
        oce_free_wqed(wq, wqed);
        RING_GET(wq->ring, wqe_freed);
        atomic_add_32(&wq->wq_free, wqe_freed);
        /* clear the valid bit and progress cqe */
        WQ_CQE_INVALIDATE(cqe);
        RING_GET(cq->ring, 1);
        cqe = RING_GET_CONSUMER_ITEM_VA(cq->ring,
            struct oce_nic_tx_cqe);
        num_cqe++;
    } /* for all valid CQE */
    mutex_exit(&wq->txc_lock);
    if (num_cqe)
        oce_arm_cq(wq->parent, cq->cq_id, num_cqe, rearm);
    return (num_cqe);
} /* oce_process_tx_completion */

/*
 * function to drain a TxCQ and process its CQEs
 *
 * dev - software handle to the device
 * cq - pointer to the cq to drain
 *
 * return the number of CQEs processed
 */
uint16_t
oce_drain_wq_cq(void *arg)
{
    uint16_t num_cqe = 0;
    struct oce_dev *dev;
    struct oce_wq *wq;

    wq = (struct oce_wq *)arg;
    dev = wq->parent;

    /* do while we do not reach a cqe that is not valid */
    num_cqe = oce_process_tx_compl(wq, B_FALSE);

    /* check if we need to restart Tx */
    if (wq->resched && num_cqe) {
        wq->resched = B_FALSE;
        mac_tx_update(dev->mac_handle);
    }

    return (num_cqe);
} /* oce_process_wq_cqe */

/*
 * function to insert vtag to packet
 *
 * mp - mblk pointer
 * vlan_tag - tag to be inserted
 *
 * return none
 */
static inline void
oce_insert_vtag(mblk_t *mp, uint16_t vlan_tag)
{
    struct ether_vlan_header  *evh;
    (void) memmove(mp->b_rptr - VLAN_TAGSZ,
        mp->b_rptr, 2 * ETHERADDRL);
    mp->b_rptr -= VLAN_TAGSZ;
    evh = (struct ether_vlan_header *)(void *)mp->b_rptr;
    evh->ether_tpid = htons(VLAN_TPID);
    evh->ether_tci = htons(vlan_tag);
}

/*
 * function to strip  vtag from packet
 *
 * mp - mblk pointer
 *
 * return none
 */

static inline void
oce_remove_vtag(mblk_t *mp)
{
    (void) memmove(mp->b_rptr + VLAN_TAGSZ, mp->b_rptr,
        ETHERADDRL * 2);
    mp->b_rptr += VLAN_TAGSZ;
}

/*
 * function to xmit  Single packet over the wire
 *
 * wq - pointer to WQ
 * mp - Pointer to packet chain
 *
 * return pointer to the packet
 */
mblk_t *
oce_send_packet(struct oce_wq *wq, mblk_t *mp)
{

    struct oce_nic_hdr_wqe *wqeh;
    struct oce_dev *dev;
    struct ether_header *eh;
    struct ether_vlan_header *evh;
    int32_t num_wqes;
    uint16_t etype;
    uint32_t ip_offset;
    uint32_t csum_flags = 0;
    boolean_t use_copy = B_FALSE;
    boolean_t tagged   = B_FALSE;
    uint16_t  vlan_tag;
    uint32_t  reg_value = 0;
    oce_wqe_desc_t *wqed = NULL;
    mblk_t *nmp = NULL;
    mblk_t *tmp = NULL;
    uint32_t pkt_len = 0;
    int num_mblks = 0;
    int ret = 0;
    uint32_t flags = 0;
    uint32_t mss = 0;

    /* retrieve the adap priv struct ptr */
    dev = wq->parent;

    /* check if we have enough free slots */
    if (wq->wq_free < wq->cfg.q_len/2) {
        (void) oce_process_tx_compl(wq, B_FALSE);
    }
    if (wq->wq_free < OCE_MAX_TX_HDL) {
        return (mp);
    }

    /* check if we should copy */
    for (tmp = mp; tmp != NULL; tmp = tmp->b_cont) {
        pkt_len += MBLKL(tmp);
        num_mblks++;
    }

    /* Retrieve LSO info */
    mac_lso_get(mp, &mss, &flags);

    /* get the offload flags */
    mac_hcksum_get(mp, NULL, NULL, NULL, NULL, &csum_flags);

    /* Limit should be always less than Tx Buffer Size */
    if (pkt_len < dev->tx_bcopy_limit) {
        use_copy = B_TRUE;
    } else {
        /* restrict the mapped segment to wat we support */
        if (num_mblks  > OCE_MAX_TX_HDL) {
            nmp = msgpullup(mp, -1);
            if (nmp == NULL) {
                atomic_inc_32(&wq->pkt_drops);
                freemsg(mp);
                return (NULL);
            }
            /* Reset it to new collapsed mp */
            freemsg(mp);
            mp = nmp;
        }
    }

    /* Get the packet descriptor for Tx */
    wqed = kmem_cache_alloc(wq->wqed_cache, KM_NOSLEEP);
    if (wqed == NULL) {
        atomic_inc_32(&wq->pkt_drops);
        freemsg(mp);
        return (NULL);
    }
    eh = (struct ether_header *)(void *)mp->b_rptr;
    if (ntohs(eh->ether_type) == VLAN_TPID) {
        evh = (struct ether_vlan_header *)(void *)mp->b_rptr;
        tagged = B_TRUE;
        etype = ntohs(evh->ether_type);
        ip_offset = sizeof (struct ether_vlan_header);
        pkt_len -= VLAN_TAGSZ;
        vlan_tag = ntohs(evh->ether_tci);
        oce_remove_vtag(mp);
    } else {
        etype = ntohs(eh->ether_type);
        ip_offset = sizeof (struct ether_header);
    }
    bzero(wqed, sizeof (oce_wqe_desc_t));

    /* Save the WQ pointer */
    wqed->wq = wq;
    if (use_copy == B_TRUE) {
        ret = oce_bcopy_wqe(wq, wqed, mp, pkt_len);
    } else {
        ret = oce_map_wqe(wq, wqed, mp);
    }

    /*
     * Any failure other than insufficient Q entries
     * drop the packet
     */
    if (ret != 0) {
        kmem_cache_free(wq->wqed_cache, wqed);
        /* drop the packet */
        atomic_inc_32(&wq->pkt_drops);
        freemsg(mp);
        return (NULL);
    }

    /* increment pending wqed to be scheduled */
    wqeh = (struct oce_nic_hdr_wqe *)&wqed->frag[0];

    /* fill rest of wqe header fields based on packet */
    if (flags & HW_LSO) {
        wqeh->u0.s.lso = B_TRUE;
        wqeh->u0.s.lso_mss = mss;
    }
    if (csum_flags & HCK_FULLCKSUM) {
        uint8_t *proto;
        if (etype == ETHERTYPE_IP) {
            proto = (uint8_t *)(void *)
                (mp->b_rptr + ip_offset);
            if (proto[9] == 6)
                /* IPPROTO_TCP */
                wqeh->u0.s.tcpcs = B_TRUE;
            else if (proto[9] == 17)
                /* IPPROTO_UDP */
                wqeh->u0.s.udpcs = B_TRUE;
        }
    }

    if (csum_flags & HCK_IPV4_HDRCKSUM)
        wqeh->u0.s.ipcs = B_TRUE;
    if (tagged) {
        wqeh->u0.s.vlan = B_TRUE;
        wqeh->u0.s.vlan_tag = vlan_tag;
    }

    wqeh->u0.s.complete = B_TRUE;
    wqeh->u0.s.event = B_TRUE;
    wqeh->u0.s.crc = B_TRUE;
    wqeh->u0.s.total_length = pkt_len;

    /* frag count +  header wqe */
    num_wqes = wqed->frag_cnt;

    /* h/w expects even no. of WQEs */
    if (num_wqes & 0x1)
        num_wqes++;
    wqed->wqe_cnt = (uint16_t)num_wqes;
    wqeh->u0.s.num_wqe = num_wqes;
    DW_SWAP(u32ptr(&wqed->frag[0]), (wqed->wqe_cnt * NIC_WQE_SIZE));

    mutex_enter(&wq->tx_lock);
    if (num_wqes > wq->wq_free) {
        atomic_inc_32(&wq->tx_deferd);
        mutex_exit(&wq->tx_lock);
        goto wqe_fail;
    }
    atomic_add_32(&wq->wq_free, -num_wqes);
    wqed->wq_start_idx = wq->ring->pidx;

    /* fill the wq for adapter */
    oce_fill_ring_descs(wq, wqed);

    /* Add the packet desc to list to be retrieved during cmpl */
    OCE_LIST_INSERT_TAIL(&wq->wqe_desc_list,  wqed);

    /* ring tx doorbell */
    reg_value = (num_wqes << 16) | wq->wq_id;
    /* Ring the door bell  */
    OCE_DB_WRITE32(dev, PD_TXULP_DB, reg_value);
    mutex_exit(&wq->tx_lock);

    /* free mp if copied or packet chain collapsed */
    if (use_copy == B_TRUE) {
        freemsg(mp);
    }
    return (NULL);

wqe_fail:

    if (tagged) {
        oce_insert_vtag(mp, vlan_tag);
    }

    /* set it to null in case map_wqe has set it */
    wqed->mp = NULL;
    oce_free_wqed(wq, wqed);
    return (mp);
} /* oce_send_packet */

/*
 * function to free the WQE descriptor
 *
 * wq - pointer to WQ
 * wqed - Pointer to WQE descriptor
 *
 * return none
 */
#pragma inline(oce_free_wqed)
static void
oce_free_wqed(struct oce_wq *wq, oce_wqe_desc_t *wqed)
{
    if (wqed == NULL) {
        return;
    }

    if (wqed->type == COPY_WQE) {
        oce_wqb_free(wq, wqed->hdesc[0].hdl);
    } else if (wqed->type == MAPPED_WQE) {
        oce_wqmd_free(wq, wqed);
    } else ASSERT(0);

    if (wqed->mp)
        freemsg(wqed->mp);
    kmem_cache_free(wq->wqed_cache, wqed);
} /* oce_free_wqed */

/*
 * function to start the WQ
 *
 * wq - pointer to WQ
 *
 * return DDI_SUCCESS
 */

int
oce_start_wq(struct oce_wq *wq)
{
    _NOTE(ARGUNUSED(wq));
    return (DDI_SUCCESS);
} /* oce_start_wq */

/*
 * function to stop  the WQ
 *
 * wq - pointer to WQ
 *
 * return none
 */
void
oce_clean_wq(struct oce_wq *wq)
{
    oce_wqe_desc_t *wqed;
    int ti;

    /* Wait for already posted Tx to complete */

    for (ti = 0; ti < DEFAULT_DRAIN_TIME; ti++) {
        (void) oce_process_tx_compl(wq, B_FALSE);
        OCE_MSDELAY(1);
    }

    /* Free the remaining descriptors */
    while ((wqed = OCE_LIST_REM_HEAD(&wq->wqe_desc_list)) != NULL) {
        atomic_add_32(&wq->wq_free, wqed->wqe_cnt);
        oce_free_wqed(wq, wqed);
    }
    oce_drain_eq(wq->cq->eq);
} /* oce_stop_wq */

/*
 * function to set the tx mapping handle fma attr
 *
 * fm_caps - capability flags
 *
 * return none
 */

void
oce_set_tx_map_dma_fma_flags(int fm_caps)
{
    if (fm_caps == DDI_FM_NOT_CAPABLE) {
        return;
    }

    if (DDI_FM_DMA_ERR_CAP(fm_caps)) {
        tx_map_dma_attr.dma_attr_flags |= DDI_DMA_FLAGERR;
    } else {
        tx_map_dma_attr.dma_attr_flags &= ~DDI_DMA_FLAGERR;
    }
} /* oce_set_tx_map_dma_fma_flags */