/*
 * Copyright (c) 2018, Mellanox Technologies. 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/bpf_trace.h>
#include <net/xdp_sock_drv.h>
#include "en/xdp.h"
#include "en/params.h"

int mlx5e_xdp_max_mtu(struct mlx5e_params *params, struct mlx5e_xsk_param *xsk)
{
        int hr = mlx5e_get_linear_rq_headroom(params, xsk);

        /* Let S := SKB_DATA_ALIGN(sizeof(struct skb_shared_info)).
         * The condition checked in mlx5e_rx_is_linear_skb is:
         *   SKB_DATA_ALIGN(sw_mtu + hard_mtu + hr) + S <= PAGE_SIZE         (1)
         *   (Note that hw_mtu == sw_mtu + hard_mtu.)
         * What is returned from this function is:
         *   max_mtu = PAGE_SIZE - S - hr - hard_mtu                         (2)
         * After assigning sw_mtu := max_mtu, the left side of (1) turns to
         * SKB_DATA_ALIGN(PAGE_SIZE - S) + S, which is equal to PAGE_SIZE,
         * because both PAGE_SIZE and S are already aligned. Any number greater
         * than max_mtu would make the left side of (1) greater than PAGE_SIZE,
         * so max_mtu is the maximum MTU allowed.
         */

        return MLX5E_HW2SW_MTU(params, SKB_MAX_HEAD(hr));
}

static inline bool
mlx5e_xmit_xdp_buff(struct mlx5e_xdpsq *sq, struct mlx5e_rq *rq,
                    struct mlx5e_dma_info *di, struct xdp_buff *xdp)
{
        struct mlx5e_xmit_data xdptxd;
        struct mlx5e_xdp_info xdpi;
        struct xdp_frame *xdpf;
        dma_addr_t dma_addr;

        xdpf = xdp_convert_buff_to_frame(xdp);
        if (unlikely(!xdpf))
                return false;

        xdptxd.data = xdpf->data;
        xdptxd.len  = xdpf->len;

        if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) {
                /* The xdp_buff was in the UMEM and was copied into a newly
                 * allocated page. The UMEM page was returned via the ZCA, and
                 * this new page has to be mapped at this point and has to be
                 * unmapped and returned via xdp_return_frame on completion.
                 */

                /* Prevent double recycling of the UMEM page. Even in case this
                 * function returns false, the xdp_buff shouldn't be recycled,
                 * as it was already done in xdp_convert_zc_to_xdp_frame.
                 */
                __set_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags); /* non-atomic */

                xdpi.mode = MLX5E_XDP_XMIT_MODE_FRAME;

                dma_addr = dma_map_single(sq->pdev, xdptxd.data, xdptxd.len,
                                          DMA_TO_DEVICE);
                if (dma_mapping_error(sq->pdev, dma_addr)) {
                        xdp_return_frame(xdpf);
                        return false;
                }

                xdptxd.dma_addr     = dma_addr;
                xdpi.frame.xdpf     = xdpf;
                xdpi.frame.dma_addr = dma_addr;
        } else {
                /* Driver assumes that xdp_convert_buff_to_frame returns
                 * an xdp_frame that points to the same memory region as
                 * the original xdp_buff. It allows to map the memory only
                 * once and to use the DMA_BIDIRECTIONAL mode.
                 */

                xdpi.mode = MLX5E_XDP_XMIT_MODE_PAGE;

                dma_addr = di->addr + (xdpf->data - (void *)xdpf);
                dma_sync_single_for_device(sq->pdev, dma_addr, xdptxd.len,
                                           DMA_TO_DEVICE);

                xdptxd.dma_addr = dma_addr;
                xdpi.page.rq    = rq;
                xdpi.page.di    = *di;
        }

        return INDIRECT_CALL_2(sq->xmit_xdp_frame, mlx5e_xmit_xdp_frame_mpwqe,
                               mlx5e_xmit_xdp_frame, sq, &xdptxd, &xdpi, 0);
}

/* returns true if packet was consumed by xdp */
bool mlx5e_xdp_handle(struct mlx5e_rq *rq, struct mlx5e_dma_info *di,
                      u32 *len, struct xdp_buff *xdp)
{
        struct bpf_prog *prog = rcu_dereference(rq->xdp_prog);
        u32 act;
        int err;

        if (!prog)
                return false;

        act = bpf_prog_run_xdp(prog, xdp);
        switch (act) {
        case XDP_PASS:
                *len = xdp->data_end - xdp->data;
                return false;
        case XDP_TX:
                if (unlikely(!mlx5e_xmit_xdp_buff(rq->xdpsq, rq, di, xdp)))
                        goto xdp_abort;
                __set_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags); /* non-atomic */
                return true;
        case XDP_REDIRECT:
                /* When XDP enabled then page-refcnt==1 here */
                err = xdp_do_redirect(rq->netdev, xdp, prog);
                if (unlikely(err))
                        goto xdp_abort;
                __set_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags);
                __set_bit(MLX5E_RQ_FLAG_XDP_REDIRECT, rq->flags);
                if (xdp->rxq->mem.type != MEM_TYPE_XSK_BUFF_POOL)
                        mlx5e_page_dma_unmap(rq, di);
                rq->stats->xdp_redirect++;
                return true;
        default:
                bpf_warn_invalid_xdp_action(act);
                fallthrough;
        case XDP_ABORTED:
xdp_abort:
                trace_xdp_exception(rq->netdev, prog, act);
                fallthrough;
        case XDP_DROP:
                rq->stats->xdp_drop++;
                return true;
        }
}

static u16 mlx5e_xdpsq_get_next_pi(struct mlx5e_xdpsq *sq, u16 size)
{
        struct mlx5_wq_cyc *wq = &sq->wq;
        u16 pi, contig_wqebbs;

        pi = mlx5_wq_cyc_ctr2ix(wq, sq->pc);
        contig_wqebbs = mlx5_wq_cyc_get_contig_wqebbs(wq, pi);
        if (unlikely(contig_wqebbs < size)) {
                struct mlx5e_xdp_wqe_info *wi, *edge_wi;

                wi = &sq->db.wqe_info[pi];
                edge_wi = wi + contig_wqebbs;

                /* Fill SQ frag edge with NOPs to avoid WQE wrapping two pages. */
                for (; wi < edge_wi; wi++) {
                        *wi = (struct mlx5e_xdp_wqe_info) {
                                .num_wqebbs = 1,
                                .num_pkts = 0,
                        };
                        mlx5e_post_nop(wq, sq->sqn, &sq->pc);
                }
                sq->stats->nops += contig_wqebbs;

                pi = mlx5_wq_cyc_ctr2ix(wq, sq->pc);
        }

        return pi;
}

static void mlx5e_xdp_mpwqe_session_start(struct mlx5e_xdpsq *sq)
{
        struct mlx5e_tx_mpwqe *session = &sq->mpwqe;
        struct mlx5e_xdpsq_stats *stats = sq->stats;
        struct mlx5e_tx_wqe *wqe;
        u16 pi;

        pi = mlx5e_xdpsq_get_next_pi(sq, MLX5E_TX_MPW_MAX_WQEBBS);
        wqe = MLX5E_TX_FETCH_WQE(sq, pi);
        net_prefetchw(wqe->data);

        *session = (struct mlx5e_tx_mpwqe) {
                .wqe = wqe,
                .bytes_count = 0,
                .ds_count = MLX5E_TX_WQE_EMPTY_DS_COUNT,
                .pkt_count = 0,
                .inline_on = mlx5e_xdp_get_inline_state(sq, session->inline_on),
        };

        stats->mpwqe++;
}

void mlx5e_xdp_mpwqe_complete(struct mlx5e_xdpsq *sq)
{
        struct mlx5_wq_cyc       *wq    = &sq->wq;
        struct mlx5e_tx_mpwqe *session = &sq->mpwqe;
        struct mlx5_wqe_ctrl_seg *cseg = &session->wqe->ctrl;
        u16 ds_count = session->ds_count;
        u16 pi = mlx5_wq_cyc_ctr2ix(wq, sq->pc);
        struct mlx5e_xdp_wqe_info *wi = &sq->db.wqe_info[pi];

        cseg->opmod_idx_opcode =
                cpu_to_be32((sq->pc << 8) | MLX5_OPCODE_ENHANCED_MPSW);
        cseg->qpn_ds = cpu_to_be32((sq->sqn << 8) | ds_count);

        wi->num_wqebbs = DIV_ROUND_UP(ds_count, MLX5_SEND_WQEBB_NUM_DS);
        wi->num_pkts   = session->pkt_count;

        sq->pc += wi->num_wqebbs;

        sq->doorbell_cseg = cseg;

        session->wqe = NULL; /* Close session */
}

enum {
        MLX5E_XDP_CHECK_OK = 1,
        MLX5E_XDP_CHECK_START_MPWQE = 2,
};

INDIRECT_CALLABLE_SCOPE int mlx5e_xmit_xdp_frame_check_mpwqe(struct mlx5e_xdpsq *sq)
{
        if (unlikely(!sq->mpwqe.wqe)) {
                const u16 stop_room = mlx5e_stop_room_for_wqe(MLX5_SEND_WQE_MAX_WQEBBS);

                if (unlikely(!mlx5e_wqc_has_room_for(&sq->wq, sq->cc, sq->pc,
                                                     stop_room))) {
                        /* SQ is full, ring doorbell */
                        mlx5e_xmit_xdp_doorbell(sq);
                        sq->stats->full++;
                        return -EBUSY;
                }

                return MLX5E_XDP_CHECK_START_MPWQE;
        }

        return MLX5E_XDP_CHECK_OK;
}

INDIRECT_CALLABLE_SCOPE bool
mlx5e_xmit_xdp_frame_mpwqe(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
                           struct mlx5e_xdp_info *xdpi, int check_result)
{
        struct mlx5e_tx_mpwqe *session = &sq->mpwqe;
        struct mlx5e_xdpsq_stats *stats = sq->stats;

        if (unlikely(xdptxd->len > sq->hw_mtu)) {
                stats->err++;
                return false;
        }

        if (!check_result)
                check_result = mlx5e_xmit_xdp_frame_check_mpwqe(sq);
        if (unlikely(check_result < 0))
                return false;

        if (check_result == MLX5E_XDP_CHECK_START_MPWQE) {
                /* Start the session when nothing can fail, so it's guaranteed
                 * that if there is an active session, it has at least one dseg,
                 * and it's safe to complete it at any time.
                 */
                mlx5e_xdp_mpwqe_session_start(sq);
        }

        mlx5e_xdp_mpwqe_add_dseg(sq, xdptxd, stats);

        if (unlikely(mlx5e_xdp_mpqwe_is_full(session)))
                mlx5e_xdp_mpwqe_complete(sq);

        mlx5e_xdpi_fifo_push(&sq->db.xdpi_fifo, xdpi);
        stats->xmit++;
        return true;
}

INDIRECT_CALLABLE_SCOPE int mlx5e_xmit_xdp_frame_check(struct mlx5e_xdpsq *sq)
{
        if (unlikely(!mlx5e_wqc_has_room_for(&sq->wq, sq->cc, sq->pc, 1))) {
                /* SQ is full, ring doorbell */
                mlx5e_xmit_xdp_doorbell(sq);
                sq->stats->full++;
                return -EBUSY;
        }

        return MLX5E_XDP_CHECK_OK;
}

INDIRECT_CALLABLE_SCOPE bool
mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
                     struct mlx5e_xdp_info *xdpi, int check_result)
{
        struct mlx5_wq_cyc       *wq   = &sq->wq;
        u16                       pi   = mlx5_wq_cyc_ctr2ix(wq, sq->pc);
        struct mlx5e_tx_wqe      *wqe  = mlx5_wq_cyc_get_wqe(wq, pi);

        struct mlx5_wqe_ctrl_seg *cseg = &wqe->ctrl;
        struct mlx5_wqe_eth_seg  *eseg = &wqe->eth;
        struct mlx5_wqe_data_seg *dseg = wqe->data;

        dma_addr_t dma_addr = xdptxd->dma_addr;
        u32 dma_len = xdptxd->len;

        struct mlx5e_xdpsq_stats *stats = sq->stats;

        net_prefetchw(wqe);

        if (unlikely(dma_len < MLX5E_XDP_MIN_INLINE || sq->hw_mtu < dma_len)) {
                stats->err++;
                return false;
        }

        if (!check_result)
                check_result = mlx5e_xmit_xdp_frame_check(sq);
        if (unlikely(check_result < 0))
                return false;

        cseg->fm_ce_se = 0;

        /* copy the inline part if required */
        if (sq->min_inline_mode != MLX5_INLINE_MODE_NONE) {
                memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE);
                eseg->inline_hdr.sz = cpu_to_be16(MLX5E_XDP_MIN_INLINE);
                dma_len  -= MLX5E_XDP_MIN_INLINE;
                dma_addr += MLX5E_XDP_MIN_INLINE;
                dseg++;
        }

        /* write the dma part */
        dseg->addr       = cpu_to_be64(dma_addr);
        dseg->byte_count = cpu_to_be32(dma_len);

        cseg->opmod_idx_opcode = cpu_to_be32((sq->pc << 8) | MLX5_OPCODE_SEND);

        sq->pc++;

        sq->doorbell_cseg = cseg;

        mlx5e_xdpi_fifo_push(&sq->db.xdpi_fifo, xdpi);
        stats->xmit++;
        return true;
}

static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq,
                                  struct mlx5e_xdp_wqe_info *wi,
                                  u32 *xsk_frames,
                                  bool recycle,
                                  struct xdp_frame_bulk *bq)
{
        struct mlx5e_xdp_info_fifo *xdpi_fifo = &sq->db.xdpi_fifo;
        u16 i;

        for (i = 0; i < wi->num_pkts; i++) {
                struct mlx5e_xdp_info xdpi = mlx5e_xdpi_fifo_pop(xdpi_fifo);

                switch (xdpi.mode) {
                case MLX5E_XDP_XMIT_MODE_FRAME:
                        /* XDP_TX from the XSK RQ and XDP_REDIRECT */
                        dma_unmap_single(sq->pdev, xdpi.frame.dma_addr,
                                         xdpi.frame.xdpf->len, DMA_TO_DEVICE);
                        xdp_return_frame_bulk(xdpi.frame.xdpf, bq);
                        break;
                case MLX5E_XDP_XMIT_MODE_PAGE:
                        /* XDP_TX from the regular RQ */
                        mlx5e_page_release_dynamic(xdpi.page.rq, &xdpi.page.di, recycle);
                        break;
                case MLX5E_XDP_XMIT_MODE_XSK:
                        /* AF_XDP send */
                        (*xsk_frames)++;
                        break;
                default:
                        WARN_ON_ONCE(true);
                }
        }
}

bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)
{
        struct xdp_frame_bulk bq;
        struct mlx5e_xdpsq *sq;
        struct mlx5_cqe64 *cqe;
        u32 xsk_frames = 0;
        u16 sqcc;
        int i;

        xdp_frame_bulk_init(&bq);

        sq = container_of(cq, struct mlx5e_xdpsq, cq);

        if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))
                return false;

        cqe = mlx5_cqwq_get_cqe(&cq->wq);
        if (!cqe)
                return false;

        /* sq->cc must be updated only after mlx5_cqwq_update_db_record(),
         * otherwise a cq overrun may occur
         */
        sqcc = sq->cc;

        i = 0;
        do {
                struct mlx5e_xdp_wqe_info *wi;
                u16 wqe_counter, ci;
                bool last_wqe;

                mlx5_cqwq_pop(&cq->wq);

                wqe_counter = be16_to_cpu(cqe->wqe_counter);

                do {
                        last_wqe = (sqcc == wqe_counter);
                        ci = mlx5_wq_cyc_ctr2ix(&sq->wq, sqcc);
                        wi = &sq->db.wqe_info[ci];

                        sqcc += wi->num_wqebbs;

                        mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, true, &bq);
                } while (!last_wqe);

                if (unlikely(get_cqe_opcode(cqe) != MLX5_CQE_REQ)) {
                        netdev_WARN_ONCE(sq->channel->netdev,
                                         "Bad OP in XDPSQ CQE: 0x%x\n",
                                         get_cqe_opcode(cqe));
                        mlx5e_dump_error_cqe(&sq->cq, sq->sqn,
                                             (struct mlx5_err_cqe *)cqe);
                        mlx5_wq_cyc_wqe_dump(&sq->wq, ci, wi->num_wqebbs);
                }
        } while ((++i < MLX5E_TX_CQ_POLL_BUDGET) && (cqe = mlx5_cqwq_get_cqe(&cq->wq)));

        xdp_flush_frame_bulk(&bq);

        if (xsk_frames)
                xsk_tx_completed(sq->xsk_pool, xsk_frames);

        sq->stats->cqes += i;

        mlx5_cqwq_update_db_record(&cq->wq);

        /* ensure cq space is freed before enabling more cqes */
        wmb();

        sq->cc = sqcc;
        return (i == MLX5E_TX_CQ_POLL_BUDGET);
}

void mlx5e_free_xdpsq_descs(struct mlx5e_xdpsq *sq)
{
        struct xdp_frame_bulk bq;
        u32 xsk_frames = 0;

        xdp_frame_bulk_init(&bq);

        rcu_read_lock(); /* need for xdp_return_frame_bulk */

        while (sq->cc != sq->pc) {
                struct mlx5e_xdp_wqe_info *wi;
                u16 ci;

                ci = mlx5_wq_cyc_ctr2ix(&sq->wq, sq->cc);
                wi = &sq->db.wqe_info[ci];

                sq->cc += wi->num_wqebbs;

                mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, false, &bq);
        }

        xdp_flush_frame_bulk(&bq);
        rcu_read_unlock();

        if (xsk_frames)
                xsk_tx_completed(sq->xsk_pool, xsk_frames);
}

int mlx5e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
                   u32 flags)
{
        struct mlx5e_priv *priv = netdev_priv(dev);
        struct mlx5e_xdpsq *sq;
        int nxmit = 0;
        int sq_num;
        int i;

        /* this flag is sufficient, no need to test internal sq state */
        if (unlikely(!mlx5e_xdp_tx_is_enabled(priv)))
                return -ENETDOWN;

        if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
                return -EINVAL;

        sq_num = smp_processor_id();

        if (unlikely(sq_num >= priv->channels.num))
                return -ENXIO;

        sq = &priv->channels.c[sq_num]->xdpsq;

        for (i = 0; i < n; i++) {
                struct xdp_frame *xdpf = frames[i];
                struct mlx5e_xmit_data xdptxd;
                struct mlx5e_xdp_info xdpi;
                bool ret;

                xdptxd.data = xdpf->data;
                xdptxd.len = xdpf->len;
                xdptxd.dma_addr = dma_map_single(sq->pdev, xdptxd.data,
                                                 xdptxd.len, DMA_TO_DEVICE);

                if (unlikely(dma_mapping_error(sq->pdev, xdptxd.dma_addr)))
                        break;

                xdpi.mode           = MLX5E_XDP_XMIT_MODE_FRAME;
                xdpi.frame.xdpf     = xdpf;
                xdpi.frame.dma_addr = xdptxd.dma_addr;

                ret = INDIRECT_CALL_2(sq->xmit_xdp_frame, mlx5e_xmit_xdp_frame_mpwqe,
                                      mlx5e_xmit_xdp_frame, sq, &xdptxd, &xdpi, 0);
                if (unlikely(!ret)) {
                        dma_unmap_single(sq->pdev, xdptxd.dma_addr,
                                         xdptxd.len, DMA_TO_DEVICE);
                        break;
                }
                nxmit++;
        }

        if (flags & XDP_XMIT_FLUSH) {
                if (sq->mpwqe.wqe)
                        mlx5e_xdp_mpwqe_complete(sq);
                mlx5e_xmit_xdp_doorbell(sq);
        }

        return nxmit;
}

void mlx5e_xdp_rx_poll_complete(struct mlx5e_rq *rq)
{
        struct mlx5e_xdpsq *xdpsq = rq->xdpsq;

        if (xdpsq->mpwqe.wqe)
                mlx5e_xdp_mpwqe_complete(xdpsq);

        mlx5e_xmit_xdp_doorbell(xdpsq);

        if (test_bit(MLX5E_RQ_FLAG_XDP_REDIRECT, rq->flags)) {
                xdp_do_flush_map();
                __clear_bit(MLX5E_RQ_FLAG_XDP_REDIRECT, rq->flags);
        }
}

void mlx5e_set_xmit_fp(struct mlx5e_xdpsq *sq, bool is_mpw)
{
        sq->xmit_xdp_frame_check = is_mpw ?
                mlx5e_xmit_xdp_frame_check_mpwqe : mlx5e_xmit_xdp_frame_check;
        sq->xmit_xdp_frame = is_mpw ?
                mlx5e_xmit_xdp_frame_mpwqe : mlx5e_xmit_xdp_frame;
}