// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2018 Netronome Systems, Inc */
/* Copyright (C) 2021 Corigine, Inc */

#include <linux/bpf_trace.h>
#include <linux/netdevice.h>

#include "../nfp_app.h"
#include "../nfp_net.h"
#include "../nfp_net_dp.h"
#include "../nfp_net_xsk.h"
#include "nfd3.h"

static bool
nfp_nfd3_xsk_tx_xdp(const struct nfp_net_dp *dp, struct nfp_net_r_vector *r_vec,
                    struct nfp_net_rx_ring *rx_ring,
                    struct nfp_net_tx_ring *tx_ring,
                    struct nfp_net_xsk_rx_buf *xrxbuf, unsigned int pkt_len,
                    int pkt_off)
{
        struct xsk_buff_pool *pool = r_vec->xsk_pool;
        struct nfp_nfd3_tx_buf *txbuf;
        struct nfp_nfd3_tx_desc *txd;
        unsigned int wr_idx;

        if (nfp_net_tx_space(tx_ring) < 1)
                return false;

        xsk_buff_raw_dma_sync_for_device(pool, xrxbuf->dma_addr + pkt_off,
                                         pkt_len);

        wr_idx = D_IDX(tx_ring, tx_ring->wr_p);

        txbuf = &tx_ring->txbufs[wr_idx];
        txbuf->xdp = xrxbuf->xdp;
        txbuf->real_len = pkt_len;
        txbuf->is_xsk_tx = true;

        /* Build TX descriptor */
        txd = &tx_ring->txds[wr_idx];
        txd->offset_eop = NFD3_DESC_TX_EOP;
        txd->dma_len = cpu_to_le16(pkt_len);
        nfp_desc_set_dma_addr_40b(txd, xrxbuf->dma_addr + pkt_off);
        txd->data_len = cpu_to_le16(pkt_len);

        txd->flags = 0;
        txd->mss = 0;
        txd->lso_hdrlen = 0;

        tx_ring->wr_ptr_add++;
        tx_ring->wr_p++;

        return true;
}

static void nfp_nfd3_xsk_rx_skb(struct nfp_net_rx_ring *rx_ring,
                                const struct nfp_net_rx_desc *rxd,
                                struct nfp_net_xsk_rx_buf *xrxbuf,
                                const struct nfp_meta_parsed *meta,
                                unsigned int pkt_len,
                                bool meta_xdp,
                                unsigned int *skbs_polled)
{
        struct nfp_net_r_vector *r_vec = rx_ring->r_vec;
        struct nfp_net_dp *dp = &r_vec->nfp_net->dp;
        struct net_device *netdev;
        struct sk_buff *skb;

        if (likely(!meta->portid)) {
                netdev = dp->netdev;
        } else {
                struct nfp_net *nn = netdev_priv(dp->netdev);

                netdev = nfp_app_dev_get(nn->app, meta->portid, NULL);
                if (unlikely(!netdev)) {
                        nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                        return;
                }
                nfp_repr_inc_rx_stats(netdev, pkt_len);
        }

        skb = napi_alloc_skb(&r_vec->napi, pkt_len);
        if (!skb) {
                nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                return;
        }
        skb_put_data(skb, xrxbuf->xdp->data, pkt_len);

        skb->mark = meta->mark;
        skb_set_hash(skb, meta->hash, meta->hash_type);

        skb_record_rx_queue(skb, rx_ring->idx);
        skb->protocol = eth_type_trans(skb, netdev);

        nfp_nfd3_rx_csum(dp, r_vec, rxd, meta, skb);

        if (unlikely(!nfp_net_vlan_strip(skb, rxd, meta))) {
                dev_kfree_skb_any(skb);
                nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                return;
        }

        if (meta_xdp)
                skb_metadata_set(skb,
                                 xrxbuf->xdp->data - xrxbuf->xdp->data_meta);

        napi_gro_receive(&rx_ring->r_vec->napi, skb);

        nfp_net_xsk_rx_free(xrxbuf);

        (*skbs_polled)++;
}

static unsigned int
nfp_nfd3_xsk_rx(struct nfp_net_rx_ring *rx_ring, int budget,
                unsigned int *skbs_polled)
{
        struct nfp_net_r_vector *r_vec = rx_ring->r_vec;
        struct nfp_net_dp *dp = &r_vec->nfp_net->dp;
        struct nfp_net_tx_ring *tx_ring;
        struct bpf_prog *xdp_prog;
        bool xdp_redir = false;
        int pkts_polled = 0;

        xdp_prog = READ_ONCE(dp->xdp_prog);
        tx_ring = r_vec->xdp_ring;

        while (pkts_polled < budget) {
                unsigned int meta_len, data_len, pkt_len, pkt_off;
                struct nfp_net_xsk_rx_buf *xrxbuf;
                struct nfp_net_rx_desc *rxd;
                struct nfp_meta_parsed meta;
                int idx, act;

                idx = D_IDX(rx_ring, rx_ring->rd_p);

                rxd = &rx_ring->rxds[idx];
                if (!(rxd->rxd.meta_len_dd & PCIE_DESC_RX_DD))
                        break;

                rx_ring->rd_p++;
                pkts_polled++;

                xrxbuf = &rx_ring->xsk_rxbufs[idx];

                /* If starved of buffers "drop" it and scream. */
                if (rx_ring->rd_p >= rx_ring->wr_p) {
                        nn_dp_warn(dp, "Starved of RX buffers\n");
                        nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                        break;
                }

                /* Memory barrier to ensure that we won't do other reads
                 * before the DD bit.
                 */
                dma_rmb();

                memset(&meta, 0, sizeof(meta));

                /* Only supporting AF_XDP with dynamic metadata so buffer layout
                 * is always:
                 *
                 *  ---------------------------------------------------------
                 * |  off | metadata  |             packet           | XXXX  |
                 *  ---------------------------------------------------------
                 */
                meta_len = rxd->rxd.meta_len_dd & PCIE_DESC_RX_META_LEN_MASK;
                data_len = le16_to_cpu(rxd->rxd.data_len);
                pkt_len = data_len - meta_len;

                if (unlikely(meta_len > NFP_NET_MAX_PREPEND)) {
                        nn_dp_warn(dp, "Oversized RX packet metadata %u\n",
                                   meta_len);
                        nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                        continue;
                }

                /* Stats update. */
                u64_stats_update_begin(&r_vec->rx_sync);
                r_vec->rx_pkts++;
                r_vec->rx_bytes += pkt_len;
                u64_stats_update_end(&r_vec->rx_sync);

                xrxbuf->xdp->data += meta_len;
                xrxbuf->xdp->data_end = xrxbuf->xdp->data + pkt_len;
                xdp_set_data_meta_invalid(xrxbuf->xdp);
                xsk_buff_dma_sync_for_cpu(xrxbuf->xdp);
                net_prefetch(xrxbuf->xdp->data);

                if (meta_len) {
                        if (unlikely(nfp_nfd3_parse_meta(dp->netdev, &meta,
                                                         xrxbuf->xdp->data -
                                                         meta_len,
                                                         xrxbuf->xdp->data,
                                                         pkt_len, meta_len))) {
                                nn_dp_warn(dp, "Invalid RX packet metadata\n");
                                nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                                continue;
                        }

                        if (unlikely(meta.portid)) {
                                struct nfp_net *nn = netdev_priv(dp->netdev);

                                if (meta.portid != NFP_META_PORT_ID_CTRL) {
                                        nfp_nfd3_xsk_rx_skb(rx_ring, rxd,
                                                            xrxbuf, &meta,
                                                            pkt_len, false,
                                                            skbs_polled);
                                        continue;
                                }

                                nfp_app_ctrl_rx_raw(nn->app, xrxbuf->xdp->data,
                                                    pkt_len);
                                nfp_net_xsk_rx_free(xrxbuf);
                                continue;
                        }
                }

                act = bpf_prog_run_xdp(xdp_prog, xrxbuf->xdp);

                pkt_len = xrxbuf->xdp->data_end - xrxbuf->xdp->data;
                pkt_off = xrxbuf->xdp->data - xrxbuf->xdp->data_hard_start;

                switch (act) {
                case XDP_PASS:
                        nfp_nfd3_xsk_rx_skb(rx_ring, rxd, xrxbuf, &meta, pkt_len,
                                            true, skbs_polled);
                        break;
                case XDP_TX:
                        if (!nfp_nfd3_xsk_tx_xdp(dp, r_vec, rx_ring, tx_ring,
                                                 xrxbuf, pkt_len, pkt_off))
                                nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                        else
                                nfp_net_xsk_rx_unstash(xrxbuf);
                        break;
                case XDP_REDIRECT:
                        if (xdp_do_redirect(dp->netdev, xrxbuf->xdp, xdp_prog)) {
                                nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                        } else {
                                nfp_net_xsk_rx_unstash(xrxbuf);
                                xdp_redir = true;
                        }
                        break;
                default:
                        bpf_warn_invalid_xdp_action(dp->netdev, xdp_prog, act);
                        fallthrough;
                case XDP_ABORTED:
                        trace_xdp_exception(dp->netdev, xdp_prog, act);
                        fallthrough;
                case XDP_DROP:
                        nfp_net_xsk_rx_drop(r_vec, xrxbuf);
                        break;
                }
        }

        nfp_net_xsk_rx_ring_fill_freelist(r_vec->rx_ring);

        if (xdp_redir)
                xdp_do_flush();

        if (tx_ring->wr_ptr_add)
                nfp_net_tx_xmit_more_flush(tx_ring);

        return pkts_polled;
}

void nfp_nfd3_xsk_tx_free(struct nfp_nfd3_tx_buf *txbuf)
{
        xsk_buff_free(txbuf->xdp);

        txbuf->dma_addr = 0;
        txbuf->xdp = NULL;
}

static bool nfp_nfd3_xsk_complete(struct nfp_net_tx_ring *tx_ring)
{
        struct nfp_net_r_vector *r_vec = tx_ring->r_vec;
        u32 done_pkts = 0, done_bytes = 0, reused = 0;
        bool done_all;
        int idx, todo;
        u32 qcp_rd_p;

        if (tx_ring->wr_p == tx_ring->rd_p)
                return true;

        /* Work out how many descriptors have been transmitted. */
        qcp_rd_p = nfp_qcp_rd_ptr_read(tx_ring->qcp_q);

        if (qcp_rd_p == tx_ring->qcp_rd_p)
                return true;

        todo = D_IDX(tx_ring, qcp_rd_p - tx_ring->qcp_rd_p);

        done_all = todo <= NFP_NET_XDP_MAX_COMPLETE;
        todo = min(todo, NFP_NET_XDP_MAX_COMPLETE);

        tx_ring->qcp_rd_p = D_IDX(tx_ring, tx_ring->qcp_rd_p + todo);

        done_pkts = todo;
        while (todo--) {
                struct nfp_nfd3_tx_buf *txbuf;

                idx = D_IDX(tx_ring, tx_ring->rd_p);
                tx_ring->rd_p++;

                txbuf = &tx_ring->txbufs[idx];
                if (unlikely(!txbuf->real_len))
                        continue;

                done_bytes += txbuf->real_len;
                txbuf->real_len = 0;

                if (txbuf->is_xsk_tx) {
                        nfp_nfd3_xsk_tx_free(txbuf);
                        reused++;
                }
        }

        u64_stats_update_begin(&r_vec->tx_sync);
        r_vec->tx_bytes += done_bytes;
        r_vec->tx_pkts += done_pkts;
        u64_stats_update_end(&r_vec->tx_sync);

        xsk_tx_completed(r_vec->xsk_pool, done_pkts - reused);

        WARN_ONCE(tx_ring->wr_p - tx_ring->rd_p > tx_ring->cnt,
                  "XDP TX ring corruption rd_p=%u wr_p=%u cnt=%u\n",
                  tx_ring->rd_p, tx_ring->wr_p, tx_ring->cnt);

        return done_all;
}

static void nfp_nfd3_xsk_tx(struct nfp_net_tx_ring *tx_ring)
{
        struct nfp_net_r_vector *r_vec = tx_ring->r_vec;
        struct xdp_desc desc[NFP_NET_XSK_TX_BATCH];
        struct xsk_buff_pool *xsk_pool;
        struct nfp_nfd3_tx_desc *txd;
        u32 pkts = 0, wr_idx;
        u32 i, got;

        xsk_pool = r_vec->xsk_pool;

        while (nfp_net_tx_space(tx_ring) >= NFP_NET_XSK_TX_BATCH) {
                for (i = 0; i < NFP_NET_XSK_TX_BATCH; i++)
                        if (!xsk_tx_peek_desc(xsk_pool, &desc[i]))
                                break;
                got = i;
                if (!got)
                        break;

                wr_idx = D_IDX(tx_ring, tx_ring->wr_p + i);
                prefetchw(&tx_ring->txds[wr_idx]);

                for (i = 0; i < got; i++)
                        xsk_buff_raw_dma_sync_for_device(xsk_pool, desc[i].addr,
                                                         desc[i].len);

                for (i = 0; i < got; i++) {
                        wr_idx = D_IDX(tx_ring, tx_ring->wr_p + i);

                        tx_ring->txbufs[wr_idx].real_len = desc[i].len;
                        tx_ring->txbufs[wr_idx].is_xsk_tx = false;

                        /* Build TX descriptor. */
                        txd = &tx_ring->txds[wr_idx];
                        nfp_desc_set_dma_addr_40b(txd,
                                                  xsk_buff_raw_get_dma(xsk_pool, desc[i].addr));
                        txd->offset_eop = NFD3_DESC_TX_EOP;
                        txd->dma_len = cpu_to_le16(desc[i].len);
                        txd->data_len = cpu_to_le16(desc[i].len);
                }

                tx_ring->wr_p += got;
                pkts += got;
        }

        if (!pkts)
                return;

        xsk_tx_release(xsk_pool);
        /* Ensure all records are visible before incrementing write counter. */
        wmb();
        nfp_qcp_wr_ptr_add(tx_ring->qcp_q, pkts);
}

int nfp_nfd3_xsk_poll(struct napi_struct *napi, int budget)
{
        struct nfp_net_r_vector *r_vec =
                container_of(napi, struct nfp_net_r_vector, napi);
        unsigned int pkts_polled, skbs = 0;

        pkts_polled = nfp_nfd3_xsk_rx(r_vec->rx_ring, budget, &skbs);

        if (pkts_polled < budget) {
                if (r_vec->tx_ring)
                        nfp_nfd3_tx_complete(r_vec->tx_ring, budget);

                if (!nfp_nfd3_xsk_complete(r_vec->xdp_ring))
                        pkts_polled = budget;

                nfp_nfd3_xsk_tx(r_vec->xdp_ring);

                if (pkts_polled < budget && napi_complete_done(napi, skbs))
                        nfp_net_irq_unmask(r_vec->nfp_net, r_vec->irq_entry);
        }

        return pkts_polled;
}