/*
 * Copyright(c) 2017 - 2018 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,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

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

#include "sdma.h"
#include "vnic.h"

#define HFI1_VNIC_SDMA_Q_ACTIVE   BIT(0)
#define HFI1_VNIC_SDMA_Q_DEFERRED BIT(1)

#define HFI1_VNIC_TXREQ_NAME_LEN   32
#define HFI1_VNIC_SDMA_DESC_WTRMRK 64

/*
 * struct vnic_txreq - VNIC transmit descriptor
 * @txreq: sdma transmit request
 * @sdma: vnic sdma pointer
 * @skb: skb to send
 * @pad: pad buffer
 * @plen: pad length
 * @pbc_val: pbc value
 */
struct vnic_txreq {
        struct sdma_txreq       txreq;
        struct hfi1_vnic_sdma   *sdma;

        struct sk_buff         *skb;
        unsigned char           pad[HFI1_VNIC_MAX_PAD];
        u16                     plen;
        __le64                  pbc_val;
};

static void vnic_sdma_complete(struct sdma_txreq *txreq,
                               int status)
{
        struct vnic_txreq *tx = container_of(txreq, struct vnic_txreq, txreq);
        struct hfi1_vnic_sdma *vnic_sdma = tx->sdma;

        sdma_txclean(vnic_sdma->dd, txreq);
        dev_kfree_skb_any(tx->skb);
        kmem_cache_free(vnic_sdma->dd->vnic.txreq_cache, tx);
}

static noinline int build_vnic_ulp_payload(struct sdma_engine *sde,
                                           struct vnic_txreq *tx)
{
        int i, ret = 0;

        ret = sdma_txadd_kvaddr(
                sde->dd,
                &tx->txreq,
                tx->skb->data,
                skb_headlen(tx->skb));
        if (unlikely(ret))
                goto bail_txadd;

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

                /* combine physically continuous fragments later? */
                ret = sdma_txadd_page(sde->dd,
                                      &tx->txreq,
                                      skb_frag_page(frag),
                                      frag->page_offset,
                                      skb_frag_size(frag));
                if (unlikely(ret))
                        goto bail_txadd;
        }

        if (tx->plen)
                ret = sdma_txadd_kvaddr(sde->dd, &tx->txreq,
                                        tx->pad + HFI1_VNIC_MAX_PAD - tx->plen,
                                        tx->plen);

bail_txadd:
        return ret;
}

static int build_vnic_tx_desc(struct sdma_engine *sde,
                              struct vnic_txreq *tx,
                              u64 pbc)
{
        int ret = 0;
        u16 hdrbytes = 2 << 2;  /* PBC */

        ret = sdma_txinit_ahg(
                &tx->txreq,
                0,
                hdrbytes + tx->skb->len + tx->plen,
                0,
                0,
                NULL,
                0,
                vnic_sdma_complete);
        if (unlikely(ret))
                goto bail_txadd;

        /* add pbc */
        tx->pbc_val = cpu_to_le64(pbc);
        ret = sdma_txadd_kvaddr(
                sde->dd,
                &tx->txreq,
                &tx->pbc_val,
                hdrbytes);
        if (unlikely(ret))
                goto bail_txadd;

        /* add the ulp payload */
        ret = build_vnic_ulp_payload(sde, tx);
bail_txadd:
        return ret;
}

/* setup the last plen bypes of pad */
static inline void hfi1_vnic_update_pad(unsigned char *pad, u8 plen)
{
        pad[HFI1_VNIC_MAX_PAD - 1] = plen - OPA_VNIC_ICRC_TAIL_LEN;
}

int hfi1_vnic_send_dma(struct hfi1_devdata *dd, u8 q_idx,
                       struct hfi1_vnic_vport_info *vinfo,
                       struct sk_buff *skb, u64 pbc, u8 plen)
{
        struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
        struct sdma_engine *sde = vnic_sdma->sde;
        struct vnic_txreq *tx;
        int ret = -ECOMM;

        if (unlikely(READ_ONCE(vnic_sdma->state) != HFI1_VNIC_SDMA_Q_ACTIVE))
                goto tx_err;

        if (unlikely(!sde || !sdma_running(sde)))
                goto tx_err;

        tx = kmem_cache_alloc(dd->vnic.txreq_cache, GFP_ATOMIC);
        if (unlikely(!tx)) {
                ret = -ENOMEM;
                goto tx_err;
        }

        tx->sdma = vnic_sdma;
        tx->skb = skb;
        hfi1_vnic_update_pad(tx->pad, plen);
        tx->plen = plen;
        ret = build_vnic_tx_desc(sde, tx, pbc);
        if (unlikely(ret))
                goto free_desc;

        ret = sdma_send_txreq(sde, iowait_get_ib_work(&vnic_sdma->wait),
                              &tx->txreq, vnic_sdma->pkts_sent);
        /* When -ECOMM, sdma callback will be called with ABORT status */
        if (unlikely(ret && unlikely(ret != -ECOMM)))
                goto free_desc;

        if (!ret) {
                vnic_sdma->pkts_sent = true;
                iowait_starve_clear(vnic_sdma->pkts_sent, &vnic_sdma->wait);
        }
        return ret;

free_desc:
        sdma_txclean(dd, &tx->txreq);
        kmem_cache_free(dd->vnic.txreq_cache, tx);
tx_err:
        if (ret != -EBUSY)
                dev_kfree_skb_any(skb);
        else
                vnic_sdma->pkts_sent = false;
        return ret;
}

/*
 * hfi1_vnic_sdma_sleep - vnic 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_vnic_sdma_sleep(struct sdma_engine *sde,
                                struct iowait_work *wait,
                                struct sdma_txreq *txreq,
                                uint seq,
                                bool pkts_sent)
{
        struct hfi1_vnic_sdma *vnic_sdma =
                container_of(wait->iow, struct hfi1_vnic_sdma, wait);

        write_seqlock(&sde->waitlock);
        if (sdma_progress(sde, seq, txreq)) {
                write_sequnlock(&sde->waitlock);
                return -EAGAIN;
        }

        vnic_sdma->state = HFI1_VNIC_SDMA_Q_DEFERRED;
        if (list_empty(&vnic_sdma->wait.list)) {
                iowait_get_priority(wait->iow);
                iowait_queue(pkts_sent, wait->iow, &sde->dmawait);
        }
        write_sequnlock(&sde->waitlock);
        return -EBUSY;
}

/*
 * hfi1_vnic_sdma_wakeup - vnic 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.
 * It notifies the upper driver about Tx queue wakeup.
 */
static void hfi1_vnic_sdma_wakeup(struct iowait *wait, int reason)
{
        struct hfi1_vnic_sdma *vnic_sdma =
                container_of(wait, struct hfi1_vnic_sdma, wait);
        struct hfi1_vnic_vport_info *vinfo = vnic_sdma->vinfo;

        vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
        if (__netif_subqueue_stopped(vinfo->netdev, vnic_sdma->q_idx))
                netif_wake_subqueue(vinfo->netdev, vnic_sdma->q_idx);
};

inline bool hfi1_vnic_sdma_write_avail(struct hfi1_vnic_vport_info *vinfo,
                                       u8 q_idx)
{
        struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];

        return (READ_ONCE(vnic_sdma->state) == HFI1_VNIC_SDMA_Q_ACTIVE);
}

void hfi1_vnic_sdma_init(struct hfi1_vnic_vport_info *vinfo)
{
        int i;

        for (i = 0; i < vinfo->num_tx_q; i++) {
                struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[i];

                iowait_init(&vnic_sdma->wait, 0, NULL, NULL,
                            hfi1_vnic_sdma_sleep,
                            hfi1_vnic_sdma_wakeup, NULL, NULL);
                vnic_sdma->sde = &vinfo->dd->per_sdma[i];
                vnic_sdma->dd = vinfo->dd;
                vnic_sdma->vinfo = vinfo;
                vnic_sdma->q_idx = i;
                vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;

                /* Add a free descriptor watermark for wakeups */
                if (vnic_sdma->sde->descq_cnt > HFI1_VNIC_SDMA_DESC_WTRMRK) {
                        struct iowait_work *work;

                        INIT_LIST_HEAD(&vnic_sdma->stx.list);
                        vnic_sdma->stx.num_desc = HFI1_VNIC_SDMA_DESC_WTRMRK;
                        work = iowait_get_ib_work(&vnic_sdma->wait);
                        list_add_tail(&vnic_sdma->stx.list, &work->tx_head);
                }
        }
}

int hfi1_vnic_txreq_init(struct hfi1_devdata *dd)
{
        char buf[HFI1_VNIC_TXREQ_NAME_LEN];

        snprintf(buf, sizeof(buf), "hfi1_%u_vnic_txreq_cache", dd->unit);
        dd->vnic.txreq_cache = kmem_cache_create(buf,
                                                 sizeof(struct vnic_txreq),
                                                 0, SLAB_HWCACHE_ALIGN,
                                                 NULL);
        if (!dd->vnic.txreq_cache)
                return -ENOMEM;
        return 0;
}

void hfi1_vnic_txreq_deinit(struct hfi1_devdata *dd)
{
        kmem_cache_destroy(dd->vnic.txreq_cache);
        dd->vnic.txreq_cache = NULL;
}