// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/*
 * Copyright(c) 2020 Intel Corporation.
 *
 */

/*
 * This file contains HFI1 support for IPOIB SDMA functionality
 */

#include <linux/log2.h>
#include <linux/circ_buf.h>

#include "sdma.h"
#include "verbs.h"
#include "trace_ibhdrs.h"
#include "ipoib.h"
#include "trace_tx.h"

/* Add a convenience helper */
#define CIRC_ADD(val, add, size) (((val) + (add)) & ((size) - 1))
#define CIRC_NEXT(val, size) CIRC_ADD(val, 1, size)
#define CIRC_PREV(val, size) CIRC_ADD(val, -1, size)

struct ipoib_txparms {
        struct hfi1_devdata        *dd;
        struct rdma_ah_attr        *ah_attr;
        struct hfi1_ibport         *ibp;
        struct hfi1_ipoib_txq      *txq;
        union hfi1_ipoib_flow       flow;
        u32                         dqpn;
        u8                          hdr_dwords;
        u8                          entropy;
};

static struct ipoib_txreq *
hfi1_txreq_from_idx(struct hfi1_ipoib_circ_buf *r, u32 idx)
{
        return (struct ipoib_txreq *)(r->items + (idx << r->shift));
}

static u32 hfi1_ipoib_txreqs(const u64 sent, const u64 completed)
{
        return sent - completed;
}

static u64 hfi1_ipoib_used(struct hfi1_ipoib_txq *txq)
{
        return hfi1_ipoib_txreqs(txq->tx_ring.sent_txreqs,
                                 txq->tx_ring.complete_txreqs);
}

static void hfi1_ipoib_stop_txq(struct hfi1_ipoib_txq *txq)
{
        trace_hfi1_txq_stop(txq);
        if (atomic_inc_return(&txq->tx_ring.stops) == 1)
                netif_stop_subqueue(txq->priv->netdev, txq->q_idx);
}

static void hfi1_ipoib_wake_txq(struct hfi1_ipoib_txq *txq)
{
        trace_hfi1_txq_wake(txq);
        if (atomic_dec_and_test(&txq->tx_ring.stops))
                netif_wake_subqueue(txq->priv->netdev, txq->q_idx);
}

static uint hfi1_ipoib_ring_hwat(struct hfi1_ipoib_txq *txq)
{
        return min_t(uint, txq->priv->netdev->tx_queue_len,
                     txq->tx_ring.max_items - 1);
}

static uint hfi1_ipoib_ring_lwat(struct hfi1_ipoib_txq *txq)
{
        return min_t(uint, txq->priv->netdev->tx_queue_len,
                     txq->tx_ring.max_items) >> 1;
}

static void hfi1_ipoib_check_queue_depth(struct hfi1_ipoib_txq *txq)
{
        ++txq->tx_ring.sent_txreqs;
        if (hfi1_ipoib_used(txq) >= hfi1_ipoib_ring_hwat(txq) &&
            !atomic_xchg(&txq->tx_ring.ring_full, 1)) {
                trace_hfi1_txq_full(txq);
                hfi1_ipoib_stop_txq(txq);
        }
}

static void hfi1_ipoib_check_queue_stopped(struct hfi1_ipoib_txq *txq)
{
        struct net_device *dev = txq->priv->netdev;

        /* If shutting down just return as queue state is irrelevant */
        if (unlikely(dev->reg_state != NETREG_REGISTERED))
                return;

        /*
         * When the queue has been drained to less than half full it will be
         * restarted.
         * The size of the txreq ring is fixed at initialization.
         * The tx queue len can be adjusted upward while the interface is
         * running.
         * The tx queue len can be large enough to overflow the txreq_ring.
         * Use the minimum of the current tx_queue_len or the rings max txreqs
         * to protect against ring overflow.
         */
        if (hfi1_ipoib_used(txq) < hfi1_ipoib_ring_lwat(txq) &&
            atomic_xchg(&txq->tx_ring.ring_full, 0)) {
                trace_hfi1_txq_xmit_unstopped(txq);
                hfi1_ipoib_wake_txq(txq);
        }
}

static void hfi1_ipoib_free_tx(struct ipoib_txreq *tx, int budget)
{
        struct hfi1_ipoib_dev_priv *priv = tx->txq->priv;

        if (likely(!tx->sdma_status)) {
                dev_sw_netstats_tx_add(priv->netdev, 1, tx->skb->len);
        } else {
                ++priv->netdev->stats.tx_errors;
                dd_dev_warn(priv->dd,
                            "%s: Status = 0x%x pbc 0x%llx txq = %d sde = %d\n",
                            __func__, tx->sdma_status,
                            le64_to_cpu(tx->sdma_hdr->pbc), tx->txq->q_idx,
                            tx->txq->sde->this_idx);
        }

        napi_consume_skb(tx->skb, budget);
        tx->skb = NULL;
        sdma_txclean(priv->dd, &tx->txreq);
}

static void hfi1_ipoib_drain_tx_ring(struct hfi1_ipoib_txq *txq)
{
        struct hfi1_ipoib_circ_buf *tx_ring = &txq->tx_ring;
        int i;
        struct ipoib_txreq *tx;

        for (i = 0; i < tx_ring->max_items; i++) {
                tx = hfi1_txreq_from_idx(tx_ring, i);
                tx->complete = 0;
                dev_kfree_skb_any(tx->skb);
                tx->skb = NULL;
                sdma_txclean(txq->priv->dd, &tx->txreq);
        }
        tx_ring->head = 0;
        tx_ring->tail = 0;
        tx_ring->complete_txreqs = 0;
        tx_ring->sent_txreqs = 0;
        tx_ring->avail = hfi1_ipoib_ring_hwat(txq);
}

static int hfi1_ipoib_poll_tx_ring(struct napi_struct *napi, int budget)
{
        struct hfi1_ipoib_txq *txq =
                container_of(napi, struct hfi1_ipoib_txq, napi);
        struct hfi1_ipoib_circ_buf *tx_ring = &txq->tx_ring;
        u32 head = tx_ring->head;
        u32 max_tx = tx_ring->max_items;
        int work_done;
        struct ipoib_txreq *tx =  hfi1_txreq_from_idx(tx_ring, head);

        trace_hfi1_txq_poll(txq);
        for (work_done = 0; work_done < budget; work_done++) {
                /* See hfi1_ipoib_sdma_complete() */
                if (!smp_load_acquire(&tx->complete))
                        break;
                tx->complete = 0;
                trace_hfi1_tx_produce(tx, head);
                hfi1_ipoib_free_tx(tx, budget);
                head = CIRC_NEXT(head, max_tx);
                tx =  hfi1_txreq_from_idx(tx_ring, head);
        }
        tx_ring->complete_txreqs += work_done;

        /* Finished freeing tx items so store the head value. */
        smp_store_release(&tx_ring->head, head);

        hfi1_ipoib_check_queue_stopped(txq);

        if (work_done < budget)
                napi_complete_done(napi, work_done);

        return work_done;
}

static void hfi1_ipoib_sdma_complete(struct sdma_txreq *txreq, int status)
{
        struct ipoib_txreq *tx = container_of(txreq, struct ipoib_txreq, txreq);

        trace_hfi1_txq_complete(tx->txq);
        tx->sdma_status = status;
        /* see hfi1_ipoib_poll_tx_ring */
        smp_store_release(&tx->complete, 1);
        napi_schedule_irqoff(&tx->txq->napi);
}

static int hfi1_ipoib_build_ulp_payload(struct ipoib_txreq *tx,
                                        struct ipoib_txparms *txp)
{
        struct hfi1_devdata *dd = txp->dd;
        struct sdma_txreq *txreq = &tx->txreq;
        struct sk_buff *skb = tx->skb;
        int ret = 0;
        int i;

        if (skb_headlen(skb)) {
                ret = sdma_txadd_kvaddr(dd, txreq, skb->data, skb_headlen(skb));
                if (unlikely(ret))
                        return ret;
        }

        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

                ret = sdma_txadd_page(dd,
                                      txreq,
                                      skb_frag_page(frag),
                                      skb_frag_off(frag),
                                      skb_frag_size(frag),
                                      NULL, NULL, NULL);
                if (unlikely(ret))
                        break;
        }

        return ret;
}

static int hfi1_ipoib_build_tx_desc(struct ipoib_txreq *tx,
                                    struct ipoib_txparms *txp)
{
        struct hfi1_devdata *dd = txp->dd;
        struct sdma_txreq *txreq = &tx->txreq;
        struct hfi1_sdma_header *sdma_hdr = tx->sdma_hdr;
        u16 pkt_bytes =
                sizeof(sdma_hdr->pbc) + (txp->hdr_dwords << 2) + tx->skb->len;
        int ret;

        ret = sdma_txinit(txreq, 0, pkt_bytes, hfi1_ipoib_sdma_complete);
        if (unlikely(ret))
                return ret;

        /* add pbc + headers */
        ret = sdma_txadd_kvaddr(dd,
                                txreq,
                                sdma_hdr,
                                sizeof(sdma_hdr->pbc) + (txp->hdr_dwords << 2));
        if (unlikely(ret))
                return ret;

        /* add the ulp payload */
        return hfi1_ipoib_build_ulp_payload(tx, txp);
}

static void hfi1_ipoib_build_ib_tx_headers(struct ipoib_txreq *tx,
                                           struct ipoib_txparms *txp)
{
        struct hfi1_ipoib_dev_priv *priv = tx->txq->priv;
        struct hfi1_sdma_header *sdma_hdr = tx->sdma_hdr;
        struct sk_buff *skb = tx->skb;
        struct hfi1_pportdata *ppd = ppd_from_ibp(txp->ibp);
        struct rdma_ah_attr *ah_attr = txp->ah_attr;
        struct ib_other_headers *ohdr;
        struct ib_grh *grh;
        u16 dwords;
        u16 slid;
        u16 dlid;
        u16 lrh0;
        u32 bth0;
        u32 sqpn = (u32)(priv->netdev->dev_addr[1] << 16 |
                         priv->netdev->dev_addr[2] << 8 |
                         priv->netdev->dev_addr[3]);
        u16 payload_dwords;
        u8 pad_cnt;

        pad_cnt = -skb->len & 3;

        /* Includes ICRC */
        payload_dwords = ((skb->len + pad_cnt) >> 2) + SIZE_OF_CRC;

        /* header size in dwords LRH+BTH+DETH = (8+12+8)/4. */
        txp->hdr_dwords = 7;

        if (rdma_ah_get_ah_flags(ah_attr) & IB_AH_GRH) {
                grh = &sdma_hdr->hdr.ibh.u.l.grh;
                txp->hdr_dwords +=
                        hfi1_make_grh(txp->ibp,
                                      grh,
                                      rdma_ah_read_grh(ah_attr),
                                      txp->hdr_dwords - LRH_9B_DWORDS,
                                      payload_dwords);
                lrh0 = HFI1_LRH_GRH;
                ohdr = &sdma_hdr->hdr.ibh.u.l.oth;
        } else {
                lrh0 = HFI1_LRH_BTH;
                ohdr = &sdma_hdr->hdr.ibh.u.oth;
        }

        lrh0 |= (rdma_ah_get_sl(ah_attr) & 0xf) << 4;
        lrh0 |= (txp->flow.sc5 & 0xf) << 12;

        dlid = opa_get_lid(rdma_ah_get_dlid(ah_attr), 9B);
        if (dlid == be16_to_cpu(IB_LID_PERMISSIVE)) {
                slid = be16_to_cpu(IB_LID_PERMISSIVE);
        } else {
                u16 lid = (u16)ppd->lid;

                if (lid) {
                        lid |= rdma_ah_get_path_bits(ah_attr) &
                                ((1 << ppd->lmc) - 1);
                        slid = lid;
                } else {
                        slid = be16_to_cpu(IB_LID_PERMISSIVE);
                }
        }

        /* Includes ICRC */
        dwords = txp->hdr_dwords + payload_dwords;

        /* Build the lrh */
        sdma_hdr->hdr.hdr_type = HFI1_PKT_TYPE_9B;
        hfi1_make_ib_hdr(&sdma_hdr->hdr.ibh, lrh0, dwords, dlid, slid);

        /* Build the bth */
        bth0 = (IB_OPCODE_UD_SEND_ONLY << 24) | (pad_cnt << 20) | priv->pkey;

        ohdr->bth[0] = cpu_to_be32(bth0);
        ohdr->bth[1] = cpu_to_be32(txp->dqpn);
        ohdr->bth[2] = cpu_to_be32(mask_psn((u32)txp->txq->tx_ring.sent_txreqs));

        /* Build the deth */
        ohdr->u.ud.deth[0] = cpu_to_be32(priv->qkey);
        ohdr->u.ud.deth[1] = cpu_to_be32((txp->entropy <<
                                          HFI1_IPOIB_ENTROPY_SHIFT) | sqpn);

        /* Construct the pbc. */
        sdma_hdr->pbc =
                cpu_to_le64(create_pbc(ppd,
                                       ib_is_sc5(txp->flow.sc5) <<
                                                              PBC_DC_INFO_SHIFT,
                                       0,
                                       sc_to_vlt(priv->dd, txp->flow.sc5),
                                       dwords - SIZE_OF_CRC +
                                                (sizeof(sdma_hdr->pbc) >> 2)));
}

static struct ipoib_txreq *hfi1_ipoib_send_dma_common(struct net_device *dev,
                                                      struct sk_buff *skb,
                                                      struct ipoib_txparms *txp)
{
        struct hfi1_ipoib_dev_priv *priv = hfi1_ipoib_priv(dev);
        struct hfi1_ipoib_txq *txq = txp->txq;
        struct ipoib_txreq *tx;
        struct hfi1_ipoib_circ_buf *tx_ring = &txq->tx_ring;
        u32 tail = tx_ring->tail;
        int ret;

        if (unlikely(!tx_ring->avail)) {
                u32 head;

                if (hfi1_ipoib_used(txq) >= hfi1_ipoib_ring_hwat(txq))
                        /* This shouldn't happen with a stopped queue */
                        return ERR_PTR(-ENOMEM);
                /* See hfi1_ipoib_poll_tx_ring() */
                head = smp_load_acquire(&tx_ring->head);
                tx_ring->avail =
                        min_t(u32, hfi1_ipoib_ring_hwat(txq),
                              CIRC_CNT(head, tail, tx_ring->max_items));
        } else {
                tx_ring->avail--;
        }
        tx = hfi1_txreq_from_idx(tx_ring, tail);
        trace_hfi1_txq_alloc_tx(txq);

        /* so that we can test if the sdma descriptors are there */
        tx->txreq.num_desc = 0;
        tx->txq = txq;
        tx->skb = skb;
        INIT_LIST_HEAD(&tx->txreq.list);

        hfi1_ipoib_build_ib_tx_headers(tx, txp);

        ret = hfi1_ipoib_build_tx_desc(tx, txp);
        if (likely(!ret)) {
                if (txq->flow.as_int != txp->flow.as_int) {
                        txq->flow.tx_queue = txp->flow.tx_queue;
                        txq->flow.sc5 = txp->flow.sc5;
                        txq->sde =
                                sdma_select_engine_sc(priv->dd,
                                                      txp->flow.tx_queue,
                                                      txp->flow.sc5);
                        trace_hfi1_flow_switch(txq);
                }

                return tx;
        }

        sdma_txclean(priv->dd, &tx->txreq);

        return ERR_PTR(ret);
}

static int hfi1_ipoib_submit_tx_list(struct net_device *dev,
                                     struct hfi1_ipoib_txq *txq)
{
        int ret;
        u16 count_out;

        ret = sdma_send_txlist(txq->sde,
                               iowait_get_ib_work(&txq->wait),
                               &txq->tx_list,
                               &count_out);
        if (likely(!ret) || ret == -EBUSY || ret == -ECOMM)
                return ret;

        dd_dev_warn(txq->priv->dd, "cannot send skb tx list, err %d.\n", ret);

        return ret;
}

static int hfi1_ipoib_flush_tx_list(struct net_device *dev,
                                    struct hfi1_ipoib_txq *txq)
{
        int ret = 0;

        if (!list_empty(&txq->tx_list)) {
                /* Flush the current list */
                ret = hfi1_ipoib_submit_tx_list(dev, txq);

                if (unlikely(ret))
                        if (ret != -EBUSY)
                                ++dev->stats.tx_carrier_errors;
        }

        return ret;
}

static int hfi1_ipoib_submit_tx(struct hfi1_ipoib_txq *txq,
                                struct ipoib_txreq *tx)
{
        int ret;

        ret = sdma_send_txreq(txq->sde,
                              iowait_get_ib_work(&txq->wait),
                              &tx->txreq,
                              txq->pkts_sent);
        if (likely(!ret)) {
                txq->pkts_sent = true;
                iowait_starve_clear(txq->pkts_sent, &txq->wait);
        }

        return ret;
}

static int hfi1_ipoib_send_dma_single(struct net_device *dev,
                                      struct sk_buff *skb,
                                      struct ipoib_txparms *txp)
{
        struct hfi1_ipoib_txq *txq = txp->txq;
        struct hfi1_ipoib_circ_buf *tx_ring;
        struct ipoib_txreq *tx;
        int ret;

        tx = hfi1_ipoib_send_dma_common(dev, skb, txp);
        if (IS_ERR(tx)) {
                int ret = PTR_ERR(tx);

                dev_kfree_skb_any(skb);

                if (ret == -ENOMEM)
                        ++dev->stats.tx_errors;
                else
                        ++dev->stats.tx_carrier_errors;

                return NETDEV_TX_OK;
        }

        tx_ring = &txq->tx_ring;
        trace_hfi1_tx_consume(tx, tx_ring->tail);
        /* consume tx */
        smp_store_release(&tx_ring->tail, CIRC_NEXT(tx_ring->tail, tx_ring->max_items));
        ret = hfi1_ipoib_submit_tx(txq, tx);
        if (likely(!ret)) {
tx_ok:
                trace_sdma_output_ibhdr(txq->priv->dd,
                                        &tx->sdma_hdr->hdr,
                                        ib_is_sc5(txp->flow.sc5));
                hfi1_ipoib_check_queue_depth(txq);
                return NETDEV_TX_OK;
        }

        txq->pkts_sent = false;

        if (ret == -EBUSY || ret == -ECOMM)
                goto tx_ok;

        /* mark complete and kick napi tx */
        smp_store_release(&tx->complete, 1);
        napi_schedule(&tx->txq->napi);

        ++dev->stats.tx_carrier_errors;

        return NETDEV_TX_OK;
}

static int hfi1_ipoib_send_dma_list(struct net_device *dev,
                                    struct sk_buff *skb,
                                    struct ipoib_txparms *txp)
{
        struct hfi1_ipoib_txq *txq = txp->txq;
        struct hfi1_ipoib_circ_buf *tx_ring;
        struct ipoib_txreq *tx;

        /* Has the flow change ? */
        if (txq->flow.as_int != txp->flow.as_int) {
                int ret;

                trace_hfi1_flow_flush(txq);
                ret = hfi1_ipoib_flush_tx_list(dev, txq);
                if (unlikely(ret)) {
                        if (ret == -EBUSY)
                                ++dev->stats.tx_dropped;
                        dev_kfree_skb_any(skb);
                        return NETDEV_TX_OK;
                }
        }
        tx = hfi1_ipoib_send_dma_common(dev, skb, txp);
        if (IS_ERR(tx)) {
                int ret = PTR_ERR(tx);

                dev_kfree_skb_any(skb);

                if (ret == -ENOMEM)
                        ++dev->stats.tx_errors;
                else
                        ++dev->stats.tx_carrier_errors;

                return NETDEV_TX_OK;
        }

        tx_ring = &txq->tx_ring;
        trace_hfi1_tx_consume(tx, tx_ring->tail);
        /* consume tx */
        smp_store_release(&tx_ring->tail, CIRC_NEXT(tx_ring->tail, tx_ring->max_items));
        list_add_tail(&tx->txreq.list, &txq->tx_list);

        hfi1_ipoib_check_queue_depth(txq);

        trace_sdma_output_ibhdr(txq->priv->dd,
                                &tx->sdma_hdr->hdr,
                                ib_is_sc5(txp->flow.sc5));

        if (!netdev_xmit_more())
                (void)hfi1_ipoib_flush_tx_list(dev, txq);

        return NETDEV_TX_OK;
}

static u8 hfi1_ipoib_calc_entropy(struct sk_buff *skb)
{
        if (skb_transport_header_was_set(skb)) {
                u8 *hdr = (u8 *)skb_transport_header(skb);

                return (hdr[0] ^ hdr[1] ^ hdr[2] ^ hdr[3]);
        }

        return (u8)skb_get_queue_mapping(skb);
}

int hfi1_ipoib_send(struct net_device *dev,
                    struct sk_buff *skb,
                    struct ib_ah *address,
                    u32 dqpn)
{
        struct hfi1_ipoib_dev_priv *priv = hfi1_ipoib_priv(dev);
        struct ipoib_txparms txp;
        struct rdma_netdev *rn = netdev_priv(dev);

        if (unlikely(skb->len > rn->mtu + HFI1_IPOIB_ENCAP_LEN)) {
                dd_dev_warn(priv->dd, "packet len %d (> %d) too long to send, dropping\n",
                            skb->len,
                            rn->mtu + HFI1_IPOIB_ENCAP_LEN);
                ++dev->stats.tx_dropped;
                ++dev->stats.tx_errors;
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }

        txp.dd = priv->dd;
        txp.ah_attr = &ibah_to_rvtah(address)->attr;
        txp.ibp = to_iport(priv->device, priv->port_num);
        txp.txq = &priv->txqs[skb_get_queue_mapping(skb)];
        txp.dqpn = dqpn;
        txp.flow.sc5 = txp.ibp->sl_to_sc[rdma_ah_get_sl(txp.ah_attr)];
        txp.flow.tx_queue = (u8)skb_get_queue_mapping(skb);
        txp.entropy = hfi1_ipoib_calc_entropy(skb);

        if (netdev_xmit_more() || !list_empty(&txp.txq->tx_list))
                return hfi1_ipoib_send_dma_list(dev, skb, &txp);

        return hfi1_ipoib_send_dma_single(dev, skb,  &txp);
}

/*
 * hfi1_ipoib_sdma_sleep - ipoib sdma sleep function
 *
 * This function gets called from sdma_send_txreq() when there are not enough
 * sdma descriptors available to send the packet. It adds Tx queue's wait
 * structure to sdma engine's dmawait list to be woken up when descriptors
 * become available.
 */
static int hfi1_ipoib_sdma_sleep(struct sdma_engine *sde,
                                 struct iowait_work *wait,
                                 struct sdma_txreq *txreq,
                                 uint seq,
                                 bool pkts_sent)
{
        struct hfi1_ipoib_txq *txq =
                container_of(wait->iow, struct hfi1_ipoib_txq, wait);

        write_seqlock(&sde->waitlock);

        if (likely(txq->priv->netdev->reg_state == NETREG_REGISTERED)) {
                if (sdma_progress(sde, seq, txreq)) {
                        write_sequnlock(&sde->waitlock);
                        return -EAGAIN;
                }

                if (list_empty(&txreq->list))
                        /* came from non-list submit */
                        list_add_tail(&txreq->list, &txq->tx_list);
                if (list_empty(&txq->wait.list)) {
                        struct hfi1_ibport *ibp = &sde->ppd->ibport_data;

                        if (!atomic_xchg(&txq->tx_ring.no_desc, 1)) {
                                trace_hfi1_txq_queued(txq);
                                hfi1_ipoib_stop_txq(txq);
                        }
                        ibp->rvp.n_dmawait++;
                        iowait_queue(pkts_sent, wait->iow, &sde->dmawait);
                }

                write_sequnlock(&sde->waitlock);
                return -EBUSY;
        }

        write_sequnlock(&sde->waitlock);
        return -EINVAL;
}

/*
 * hfi1_ipoib_sdma_wakeup - ipoib sdma wakeup function
 *
 * This function gets called when SDMA descriptors becomes available and Tx
 * queue's wait structure was previously added to sdma engine's dmawait list.
 */
static void hfi1_ipoib_sdma_wakeup(struct iowait *wait, int reason)
{
        struct hfi1_ipoib_txq *txq =
                container_of(wait, struct hfi1_ipoib_txq, wait);

        trace_hfi1_txq_wakeup(txq);
        if (likely(txq->priv->netdev->reg_state == NETREG_REGISTERED))
                iowait_schedule(wait, system_highpri_wq, WORK_CPU_UNBOUND);
}

static void hfi1_ipoib_flush_txq(struct work_struct *work)
{
        struct iowait_work *ioww =
                container_of(work, struct iowait_work, iowork);
        struct iowait *wait = iowait_ioww_to_iow(ioww);
        struct hfi1_ipoib_txq *txq =
                container_of(wait, struct hfi1_ipoib_txq, wait);
        struct net_device *dev = txq->priv->netdev;

        if (likely(dev->reg_state == NETREG_REGISTERED) &&
            likely(!hfi1_ipoib_flush_tx_list(dev, txq)))
                if (atomic_xchg(&txq->tx_ring.no_desc, 0))
                        hfi1_ipoib_wake_txq(txq);
}

int hfi1_ipoib_txreq_init(struct hfi1_ipoib_dev_priv *priv)
{
        struct net_device *dev = priv->netdev;
        u32 tx_ring_size, tx_item_size;
        struct hfi1_ipoib_circ_buf *tx_ring;
        int i, j;

        /*
         * Ring holds 1 less than tx_ring_size
         * Round up to next power of 2 in order to hold at least tx_queue_len
         */
        tx_ring_size = roundup_pow_of_two(dev->tx_queue_len + 1);
        tx_item_size = roundup_pow_of_two(sizeof(struct ipoib_txreq));

        priv->txqs = kcalloc_node(dev->num_tx_queues,
                                  sizeof(struct hfi1_ipoib_txq),
                                  GFP_KERNEL,
                                  priv->dd->node);
        if (!priv->txqs)
                return -ENOMEM;

        for (i = 0; i < dev->num_tx_queues; i++) {
                struct hfi1_ipoib_txq *txq = &priv->txqs[i];
                struct ipoib_txreq *tx;

                tx_ring = &txq->tx_ring;
                iowait_init(&txq->wait,
                            0,
                            hfi1_ipoib_flush_txq,
                            NULL,
                            hfi1_ipoib_sdma_sleep,
                            hfi1_ipoib_sdma_wakeup,
                            NULL,
                            NULL);
                txq->priv = priv;
                txq->sde = NULL;
                INIT_LIST_HEAD(&txq->tx_list);
                atomic_set(&txq->tx_ring.stops, 0);
                atomic_set(&txq->tx_ring.ring_full, 0);
                atomic_set(&txq->tx_ring.no_desc, 0);
                txq->q_idx = i;
                txq->flow.tx_queue = 0xff;
                txq->flow.sc5 = 0xff;
                txq->pkts_sent = false;

                netdev_queue_numa_node_write(netdev_get_tx_queue(dev, i),
                                             priv->dd->node);

                txq->tx_ring.items =
                        kvzalloc_node(array_size(tx_ring_size, tx_item_size),
                                      GFP_KERNEL, priv->dd->node);
                if (!txq->tx_ring.items)
                        goto free_txqs;

                txq->tx_ring.max_items = tx_ring_size;
                txq->tx_ring.shift = ilog2(tx_item_size);
                txq->tx_ring.avail = hfi1_ipoib_ring_hwat(txq);
                tx_ring = &txq->tx_ring;
                for (j = 0; j < tx_ring_size; j++) {
                        hfi1_txreq_from_idx(tx_ring, j)->sdma_hdr =
                                kzalloc_node(sizeof(*tx->sdma_hdr),
                                             GFP_KERNEL, priv->dd->node);
                        if (!hfi1_txreq_from_idx(tx_ring, j)->sdma_hdr)
                                goto free_txqs;
                }

                netif_napi_add_tx(dev, &txq->napi, hfi1_ipoib_poll_tx_ring);
        }

        return 0;

free_txqs:
        for (i--; i >= 0; i--) {
                struct hfi1_ipoib_txq *txq = &priv->txqs[i];

                netif_napi_del(&txq->napi);
                tx_ring = &txq->tx_ring;
                for (j = 0; j < tx_ring_size; j++)
                        kfree(hfi1_txreq_from_idx(tx_ring, j)->sdma_hdr);
                kvfree(tx_ring->items);
        }

        kfree(priv->txqs);
        priv->txqs = NULL;
        return -ENOMEM;
}

static void hfi1_ipoib_drain_tx_list(struct hfi1_ipoib_txq *txq)
{
        struct sdma_txreq *txreq;
        struct sdma_txreq *txreq_tmp;

        list_for_each_entry_safe(txreq, txreq_tmp, &txq->tx_list, list) {
                struct ipoib_txreq *tx =
                        container_of(txreq, struct ipoib_txreq, txreq);

                list_del(&txreq->list);
                sdma_txclean(txq->priv->dd, &tx->txreq);
                dev_kfree_skb_any(tx->skb);
                tx->skb = NULL;
                txq->tx_ring.complete_txreqs++;
        }

        if (hfi1_ipoib_used(txq))
                dd_dev_warn(txq->priv->dd,
                            "txq %d not empty found %u requests\n",
                            txq->q_idx,
                            hfi1_ipoib_txreqs(txq->tx_ring.sent_txreqs,
                                              txq->tx_ring.complete_txreqs));
}

void hfi1_ipoib_txreq_deinit(struct hfi1_ipoib_dev_priv *priv)
{
        int i, j;

        for (i = 0; i < priv->netdev->num_tx_queues; i++) {
                struct hfi1_ipoib_txq *txq = &priv->txqs[i];
                struct hfi1_ipoib_circ_buf *tx_ring = &txq->tx_ring;

                iowait_cancel_work(&txq->wait);
                iowait_sdma_drain(&txq->wait);
                hfi1_ipoib_drain_tx_list(txq);
                netif_napi_del(&txq->napi);
                hfi1_ipoib_drain_tx_ring(txq);
                for (j = 0; j < tx_ring->max_items; j++)
                        kfree(hfi1_txreq_from_idx(tx_ring, j)->sdma_hdr);
                kvfree(tx_ring->items);
        }

        kfree(priv->txqs);
        priv->txqs = NULL;
}

void hfi1_ipoib_napi_tx_enable(struct net_device *dev)
{
        struct hfi1_ipoib_dev_priv *priv = hfi1_ipoib_priv(dev);
        int i;

        for (i = 0; i < dev->num_tx_queues; i++) {
                struct hfi1_ipoib_txq *txq = &priv->txqs[i];

                napi_enable(&txq->napi);
        }
}

void hfi1_ipoib_napi_tx_disable(struct net_device *dev)
{
        struct hfi1_ipoib_dev_priv *priv = hfi1_ipoib_priv(dev);
        int i;

        for (i = 0; i < dev->num_tx_queues; i++) {
                struct hfi1_ipoib_txq *txq = &priv->txqs[i];

                napi_disable(&txq->napi);
                hfi1_ipoib_drain_tx_ring(txq);
        }
}

void hfi1_ipoib_tx_timeout(struct net_device *dev, unsigned int q)
{
        struct hfi1_ipoib_dev_priv *priv = hfi1_ipoib_priv(dev);
        struct hfi1_ipoib_txq *txq = &priv->txqs[q];

        dd_dev_info(priv->dd, "timeout txq %p q %u stopped %u stops %d no_desc %d ring_full %d\n",
                    txq, q,
                    __netif_subqueue_stopped(dev, txq->q_idx),
                    atomic_read(&txq->tx_ring.stops),
                    atomic_read(&txq->tx_ring.no_desc),
                    atomic_read(&txq->tx_ring.ring_full));
        dd_dev_info(priv->dd, "sde %p engine %u\n",
                    txq->sde,
                    txq->sde ? txq->sde->this_idx : 0);
        dd_dev_info(priv->dd, "flow %x\n", txq->flow.as_int);
        dd_dev_info(priv->dd, "sent %llu completed %llu used %llu\n",
                    txq->tx_ring.sent_txreqs, txq->tx_ring.complete_txreqs,
                    hfi1_ipoib_used(txq));
        dd_dev_info(priv->dd, "tx_queue_len %u max_items %u\n",
                    dev->tx_queue_len, txq->tx_ring.max_items);
        dd_dev_info(priv->dd, "head %u tail %u\n",
                    txq->tx_ring.head, txq->tx_ring.tail);
        dd_dev_info(priv->dd, "wait queued %u\n",
                    !list_empty(&txq->wait.list));
        dd_dev_info(priv->dd, "tx_list empty %u\n",
                    list_empty(&txq->tx_list));
}