/* Broadcom NetXtreme-C/E network driver.
 *
 * Copyright (c) 2016-2017 Broadcom Limited
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */
#undef CONFIG_BPF_SYSCALL

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/filter.h>
#include "bnxt_hsi.h"
#include "bnxt.h"
#include "bnxt_xdp.h"

void bnxt_xmit_xdp(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
                   dma_addr_t mapping, u32 len, u16 rx_prod)
{
        struct bnxt_sw_tx_bd *tx_buf;
        struct tx_bd *txbd;
        u32 flags;
        u16 prod;

        prod = txr->tx_prod;
        tx_buf = &txr->tx_buf_ring[prod];
        tx_buf->rx_prod = rx_prod;

        txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
        flags = (len << TX_BD_LEN_SHIFT) | (1 << TX_BD_FLAGS_BD_CNT_SHIFT) |
                TX_BD_FLAGS_PACKET_END | bnxt_lhint_arr[len >> 9];
        txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
        txbd->tx_bd_opaque = prod;
        txbd->tx_bd_haddr = cpu_to_le64(mapping);

        prod = NEXT_TX(prod);
        txr->tx_prod = prod;
}

void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)
{
        struct bnxt_tx_ring_info *txr = bnapi->tx_ring;
        struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;
        struct bnxt_sw_tx_bd *tx_buf;
        u16 tx_cons = txr->tx_cons;
        u16 last_tx_cons = tx_cons;
        u16 rx_prod;
        int i;

        for (i = 0; i < nr_pkts; i++) {
                last_tx_cons = tx_cons;
                tx_cons = NEXT_TX(tx_cons);
        }
        txr->tx_cons = tx_cons;
        if (bnxt_tx_avail(bp, txr) == bp->tx_ring_size) {
                rx_prod = rxr->rx_prod;
        } else {
                tx_buf = &txr->tx_buf_ring[last_tx_cons];
                rx_prod = tx_buf->rx_prod;
        }
        bnxt_db_write(bp, &rxr->rx_db, rx_prod);
}

/* returns the following:
 * true    - packet consumed by XDP and new buffer is allocated.
 * false   - packet should be passed to the stack.
 */
bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
                 struct page *page, u8 **data_ptr, unsigned int *len, u8 *event)
{
        struct bpf_prog *xdp_prog = READ_ONCE(rxr->xdp_prog);
        struct bnxt_tx_ring_info *txr;
        struct bnxt_sw_rx_bd *rx_buf;
        struct pci_dev *pdev;
        struct xdp_buff xdp;
        dma_addr_t mapping;
        void *orig_data;
        u32 tx_avail;
        u32 offset;
        u32 act;

        if (!xdp_prog)
                return false;

        pdev = bp->pdev;
        txr = rxr->bnapi->tx_ring;
        rx_buf = &rxr->rx_buf_ring[cons];
        offset = bp->rx_offset;

        xdp.data_hard_start = *data_ptr - offset;
        xdp.data = *data_ptr;
        xdp.data_end = *data_ptr + *len;
        xdp.rxq = &rxr->xdp_rxq;
        orig_data = xdp.data;
        mapping = rx_buf->mapping - bp->rx_dma_offset;

        dma_sync_single_for_cpu(&pdev->dev, mapping + offset, *len, bp->rx_dir);

        rcu_read_lock();
        act = bpf_prog_run_xdp(xdp_prog, &xdp);
        rcu_read_unlock();

        tx_avail = bnxt_tx_avail(bp, txr);
        /* If the tx ring is not full, we must not update the rx producer yet
         * because we may still be transmitting on some BDs.
         */
        if (tx_avail != bp->tx_ring_size)
                *event &= ~BNXT_RX_EVENT;

        *len = xdp.data_end - xdp.data;
        if (orig_data != xdp.data) {
                offset = xdp.data - xdp.data_hard_start;
                *data_ptr = xdp.data_hard_start + offset;
        }
        switch (act) {
        case XDP_PASS:
                return false;

        case XDP_TX:
                if (tx_avail < 1) {
                        trace_xdp_exception(bp->dev, xdp_prog, act);
                        bnxt_reuse_rx_data(rxr, cons, page);
                        return true;
                }

                *event = BNXT_TX_EVENT;
                dma_sync_single_for_device(&pdev->dev, mapping + offset, *len,
                                           bp->rx_dir);
                bnxt_xmit_xdp(bp, txr, mapping + offset, *len,
                              NEXT_RX(rxr->rx_prod));
                bnxt_reuse_rx_data(rxr, cons, page);
                return true;
        default:
                bpf_warn_invalid_xdp_action(act);
                /* Fall thru */
        case XDP_ABORTED:
                trace_xdp_exception(bp->dev, xdp_prog, act);
                /* Fall thru */
        case XDP_DROP:
                bnxt_reuse_rx_data(rxr, cons, page);
                break;
        }
        return true;
}

/* Under rtnl_lock */
static int bnxt_xdp_set(struct bnxt *bp, struct bpf_prog *prog)
{
        struct net_device *dev = bp->dev;
        int tx_xdp = 0, rc, tc;
        struct bpf_prog *old;

        if (prog && bp->dev->mtu > BNXT_MAX_PAGE_MODE_MTU) {
                netdev_warn(dev, "MTU %d larger than largest XDP supported MTU %d.\n",
                            bp->dev->mtu, BNXT_MAX_PAGE_MODE_MTU);
                return -EOPNOTSUPP;
        }
        if (!(bp->flags & BNXT_FLAG_SHARED_RINGS)) {
                netdev_warn(dev, "ethtool rx/tx channels must be combined to support XDP.\n");
                return -EOPNOTSUPP;
        }
        if (prog)
                tx_xdp = bp->rx_nr_rings;

        tc = netdev_get_num_tc(dev);
        if (!tc)
                tc = 1;
        rc = bnxt_check_rings(bp, bp->tx_nr_rings_per_tc, bp->rx_nr_rings,
                              true, tc, tx_xdp);
        if (rc) {
                netdev_warn(dev, "Unable to reserve enough TX rings to support XDP.\n");
                return rc;
        }
        if (netif_running(dev))
                bnxt_close_nic(bp, true, false);

        old = xchg(&bp->xdp_prog, prog);
        if (old)
                bpf_prog_put(old);

        if (prog) {
                bnxt_set_rx_skb_mode(bp, true);
        } else {
                int rx, tx;

                bnxt_set_rx_skb_mode(bp, false);
                bnxt_get_max_rings(bp, &rx, &tx, true);
                if (rx > 1) {
                        bp->flags &= ~BNXT_FLAG_NO_AGG_RINGS;
                        bp->dev->hw_features |= NETIF_F_LRO;
                }
        }
        bp->tx_nr_rings_xdp = tx_xdp;
        bp->tx_nr_rings = bp->tx_nr_rings_per_tc * tc + tx_xdp;
        bp->cp_nr_rings = max_t(int, bp->tx_nr_rings, bp->rx_nr_rings);
        bnxt_set_tpa_flags(bp);
        bnxt_set_ring_params(bp);

        if (netif_running(dev))
                return bnxt_open_nic(bp, true, false);

        return 0;
}

int bnxt_xdp(struct net_device *dev, struct netdev_xdp *xdp)
{
        struct bnxt *bp = netdev_priv(dev);
        int rc;

        switch (xdp->command) {
        case XDP_SETUP_PROG:
                rc = bnxt_xdp_set(bp, xdp->prog);
                break;
        case XDP_QUERY_PROG:
                xdp->prog_id = bp->xdp_prog ? bp->xdp_prog->aux->id : 0;
                rc = 0;
                break;
        default:
                rc = -EINVAL;
                break;
        }
        return rc;
}