/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2011-2014 Luigi Rizzo. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 *
 * netmap support for: re
 *
 * For more details on netmap support please see ixgbe_netmap.h
 */


#include <net/netmap.h>
#include <sys/selinfo.h>
#include <vm/vm.h>
#include <vm/pmap.h>    /* vtophys ? */
#include <dev/netmap/netmap_kern.h>


/*
 * Register/unregister. We are already under netmap lock.
 */
static int
re_netmap_reg(struct netmap_adapter *na, int onoff)
{
        if_t ifp = na->ifp;
        struct rl_softc *adapter = if_getsoftc(ifp);

        RL_LOCK(adapter);
        re_stop(adapter); /* also clears IFF_DRV_RUNNING */
        if (onoff) {
                nm_set_native_flags(na);
        } else {
                nm_clear_native_flags(na);
        }
        re_init_locked(adapter);        /* also enables intr */
        RL_UNLOCK(adapter);
        return (if_getdrvflags(ifp) & IFF_DRV_RUNNING ? 0 : 1);
}


/*
 * Reconcile kernel and user view of the transmit ring.
 */
static int
re_netmap_txsync(struct netmap_kring *kring, int flags)
{
        struct netmap_adapter *na = kring->na;
        if_t ifp = na->ifp;
        struct netmap_ring *ring = kring->ring;
        u_int nm_i;     /* index into the netmap ring */
        u_int nic_i;    /* index into the NIC ring */
        u_int n;
        u_int const lim = kring->nkr_num_slots - 1;
        u_int const head = kring->rhead;

        /* device-specific */
        struct rl_softc *sc = if_getsoftc(ifp);
        struct rl_txdesc *txd = sc->rl_ldata.rl_tx_desc;

        bus_dmamap_sync(sc->rl_ldata.rl_tx_list_tag,
            sc->rl_ldata.rl_tx_list_map,
            BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE); // XXX extra postwrite ?

        /*
         * First part: process new packets to send.
         */
        nm_i = kring->nr_hwcur;
        if (nm_i != head) {     /* we have new packets to send */
                nic_i = sc->rl_ldata.rl_tx_prodidx;
                // XXX or netmap_idx_k2n(kring, nm_i);

                for (n = 0; nm_i != head; n++) {
                        struct netmap_slot *slot = &ring->slot[nm_i];
                        u_int len = slot->len;
                        uint64_t paddr;
                        void *addr = PNMB(na, slot, &paddr);

                        /* device-specific */
                        struct rl_desc *desc = &sc->rl_ldata.rl_tx_list[nic_i];
                        int cmd = slot->len | RL_TDESC_CMD_EOF |
                                RL_TDESC_CMD_OWN | RL_TDESC_CMD_SOF ;

                        NM_CHECK_ADDR_LEN(na, addr, len);

                        if (nic_i == lim)       /* mark end of ring */
                                cmd |= RL_TDESC_CMD_EOR;

                        if (slot->flags & NS_BUF_CHANGED) {
                                /* buffer has changed, reload map */
                                desc->rl_bufaddr_lo = htole32(RL_ADDR_LO(paddr));
                                desc->rl_bufaddr_hi = htole32(RL_ADDR_HI(paddr));
                                netmap_reload_map(na, sc->rl_ldata.rl_tx_mtag,
                                        txd[nic_i].tx_dmamap, addr);
                        }
                        slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);

                        /* Fill the slot in the NIC ring. */
                        desc->rl_cmdstat = htole32(cmd);

                        /* make sure changes to the buffer are synced */
                        bus_dmamap_sync(sc->rl_ldata.rl_tx_mtag,
                                txd[nic_i].tx_dmamap,
                                BUS_DMASYNC_PREWRITE);

                        nm_i = nm_next(nm_i, lim);
                        nic_i = nm_next(nic_i, lim);
                }
                sc->rl_ldata.rl_tx_prodidx = nic_i;
                kring->nr_hwcur = head;

                /* synchronize the NIC ring */
                bus_dmamap_sync(sc->rl_ldata.rl_tx_list_tag,
                        sc->rl_ldata.rl_tx_list_map,
                        BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

                /* start ? */
                CSR_WRITE_1(sc, sc->rl_txstart, RL_TXSTART_START);
        }

        /*
         * Second part: reclaim buffers for completed transmissions.
         */
        if (flags & NAF_FORCE_RECLAIM || nm_kr_txempty(kring)) {
                nic_i = sc->rl_ldata.rl_tx_considx;
                for (n = 0; nic_i != sc->rl_ldata.rl_tx_prodidx;
                    n++, nic_i = RL_TX_DESC_NXT(sc, nic_i)) {
                        uint32_t cmdstat =
                                le32toh(sc->rl_ldata.rl_tx_list[nic_i].rl_cmdstat);
                        if (cmdstat & RL_TDESC_STAT_OWN)
                                break;
                }
                if (n > 0) {
                        sc->rl_ldata.rl_tx_considx = nic_i;
                        sc->rl_ldata.rl_tx_free += n;
                        kring->nr_hwtail = nm_prev(netmap_idx_n2k(kring, nic_i), lim);
                }
        }

        return 0;
}


/*
 * Reconcile kernel and user view of the receive ring.
 */
static int
re_netmap_rxsync(struct netmap_kring *kring, int flags)
{
        struct netmap_adapter *na = kring->na;
        if_t ifp = na->ifp;
        struct netmap_ring *ring = kring->ring;
        u_int nm_i;     /* index into the netmap ring */
        u_int nic_i;    /* index into the NIC ring */
        u_int const lim = kring->nkr_num_slots - 1;
        u_int const head = kring->rhead;
        int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;

        /* device-specific */
        struct rl_softc *sc = if_getsoftc(ifp);
        struct rl_rxdesc *rxd = sc->rl_ldata.rl_rx_desc;

        if (head > lim)
                return netmap_ring_reinit(kring);

        bus_dmamap_sync(sc->rl_ldata.rl_rx_list_tag,
                        sc->rl_ldata.rl_rx_list_map,
                        BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);

        /*
         * First part: import newly received packets.
         *
         * This device uses all the buffers in the ring, so we need
         * another termination condition in addition to RL_RDESC_STAT_OWN
         * cleared (all buffers could have it cleared). The easiest one
         * is to stop right before nm_hwcur.
         */
        if (netmap_no_pendintr || force_update) {
                uint32_t stop_i = nm_prev(kring->nr_hwcur, lim);

                nic_i = sc->rl_ldata.rl_rx_prodidx; /* next pkt to check */
                nm_i = netmap_idx_n2k(kring, nic_i);

                while (nm_i != stop_i) {
                        struct rl_desc *cur_rx = &sc->rl_ldata.rl_rx_list[nic_i];
                        uint32_t rxstat = le32toh(cur_rx->rl_cmdstat);
                        uint32_t total_len;

                        if ((rxstat & RL_RDESC_STAT_OWN) != 0)
                                break;
                        total_len = rxstat & sc->rl_rxlenmask;
                        /* XXX subtract crc */
                        total_len = (total_len < 4) ? 0 : total_len - 4;
                        ring->slot[nm_i].len = total_len;
                        ring->slot[nm_i].flags = 0;
                        /*  sync was in re_newbuf() */
                        bus_dmamap_sync(sc->rl_ldata.rl_rx_mtag,
                            rxd[nic_i].rx_dmamap, BUS_DMASYNC_POSTREAD);
                        // if_inc_counter(sc->rl_ifp, IFCOUNTER_IPACKETS, 1);
                        nm_i = nm_next(nm_i, lim);
                        nic_i = nm_next(nic_i, lim);
                }
                sc->rl_ldata.rl_rx_prodidx = nic_i;
                kring->nr_hwtail = nm_i;
                kring->nr_kflags &= ~NKR_PENDINTR;
        }

        /*
         * Second part: skip past packets that userspace has released.
         */
        nm_i = kring->nr_hwcur;
        if (nm_i != head) {
                nic_i = netmap_idx_k2n(kring, nm_i);
                while (nm_i != head) {
                        struct netmap_slot *slot = &ring->slot[nm_i];
                        uint64_t paddr;
                        void *addr = PNMB(na, slot, &paddr);

                        struct rl_desc *desc = &sc->rl_ldata.rl_rx_list[nic_i];
                        int cmd = NETMAP_BUF_SIZE(na) | RL_RDESC_CMD_OWN;

                        if (addr == NETMAP_BUF_BASE(na)) /* bad buf */
                                goto ring_reset;

                        if (nic_i == lim)       /* mark end of ring */
                                cmd |= RL_RDESC_CMD_EOR;

                        if (slot->flags & NS_BUF_CHANGED) {
                                /* buffer has changed, reload map */
                                desc->rl_bufaddr_lo = htole32(RL_ADDR_LO(paddr));
                                desc->rl_bufaddr_hi = htole32(RL_ADDR_HI(paddr));
                                netmap_reload_map(na, sc->rl_ldata.rl_rx_mtag,
                                        rxd[nic_i].rx_dmamap, addr);
                                slot->flags &= ~NS_BUF_CHANGED;
                        }
                        desc->rl_cmdstat = htole32(cmd);
                        bus_dmamap_sync(sc->rl_ldata.rl_rx_mtag,
                            rxd[nic_i].rx_dmamap,
                            BUS_DMASYNC_PREREAD);
                        nm_i = nm_next(nm_i, lim);
                        nic_i = nm_next(nic_i, lim);
                }
                kring->nr_hwcur = head;

                bus_dmamap_sync(sc->rl_ldata.rl_rx_list_tag,
                    sc->rl_ldata.rl_rx_list_map,
                    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
        }

        return 0;

ring_reset:
        return netmap_ring_reinit(kring);
}


/*
 * Additional routines to init the tx and rx rings.
 * In other drivers we do that inline in the main code.
 */
static void
re_netmap_tx_init(struct rl_softc *sc)
{
        struct rl_txdesc *txd;
        struct rl_desc *desc;
        int i, n;
        struct netmap_adapter *na = NA(sc->rl_ifp);
        struct netmap_slot *slot;

        slot = netmap_reset(na, NR_TX, 0, 0);
        /* slot is NULL if we are not in native netmap mode */
        if (!slot)
                return;
        /* in netmap mode, overwrite addresses and maps */
        txd = sc->rl_ldata.rl_tx_desc;
        desc = sc->rl_ldata.rl_tx_list;
        n = sc->rl_ldata.rl_tx_desc_cnt;

        /* l points in the netmap ring, i points in the NIC ring */
        for (i = 0; i < n; i++) {
                uint64_t paddr;
                int l = netmap_idx_n2k(na->tx_rings[0], i);
                void *addr = PNMB(na, slot + l, &paddr);

                desc[i].rl_bufaddr_lo = htole32(RL_ADDR_LO(paddr));
                desc[i].rl_bufaddr_hi = htole32(RL_ADDR_HI(paddr));
                netmap_load_map(na, sc->rl_ldata.rl_tx_mtag,
                        txd[i].tx_dmamap, addr);
        }
}

static void
re_netmap_rx_init(struct rl_softc *sc)
{
        struct netmap_adapter *na = NA(sc->rl_ifp);
        struct netmap_slot *slot = netmap_reset(na, NR_RX, 0, 0);
        struct rl_desc *desc = sc->rl_ldata.rl_rx_list;
        uint32_t cmdstat;
        uint32_t nic_i, max_avail;
        uint32_t const n = sc->rl_ldata.rl_rx_desc_cnt;

        if (!slot)
                return;
        /*
         * Do not release the slots owned by userspace,
         * and also keep one empty.
         */
        max_avail = n - 1 - nm_kr_rxspace(na->rx_rings[0]);
        for (nic_i = 0; nic_i < n; nic_i++) {
                void *addr;
                uint64_t paddr;
                uint32_t nm_i = netmap_idx_n2k(na->rx_rings[0], nic_i);

                addr = PNMB(na, slot + nm_i, &paddr);

                netmap_reload_map(na, sc->rl_ldata.rl_rx_mtag,
                    sc->rl_ldata.rl_rx_desc[nic_i].rx_dmamap, addr);
                bus_dmamap_sync(sc->rl_ldata.rl_rx_mtag,
                    sc->rl_ldata.rl_rx_desc[nic_i].rx_dmamap, BUS_DMASYNC_PREREAD);
                desc[nic_i].rl_bufaddr_lo = htole32(RL_ADDR_LO(paddr));
                desc[nic_i].rl_bufaddr_hi = htole32(RL_ADDR_HI(paddr));
                cmdstat = NETMAP_BUF_SIZE(na);
                if (nic_i == n - 1) /* mark the end of ring */
                        cmdstat |= RL_RDESC_CMD_EOR;
                if (nic_i < max_avail)
                        cmdstat |= RL_RDESC_CMD_OWN;
                desc[nic_i].rl_cmdstat = htole32(cmdstat);
        }
}


static void
re_netmap_attach(struct rl_softc *sc)
{
        struct netmap_adapter na;

        bzero(&na, sizeof(na));

        na.ifp = sc->rl_ifp;
        na.na_flags = NAF_BDG_MAYSLEEP;
        na.num_tx_desc = sc->rl_ldata.rl_tx_desc_cnt;
        na.num_rx_desc = sc->rl_ldata.rl_rx_desc_cnt;
        na.nm_txsync = re_netmap_txsync;
        na.nm_rxsync = re_netmap_rxsync;
        na.nm_register = re_netmap_reg;
        na.num_tx_rings = na.num_rx_rings = 1;
        netmap_attach(&na);
}

/* end of file */