Merge branch 'for-4.8/core' of git://git.kernel.dk/linux-block

[karo-tx-linux.git] / drivers / net / ethernet / netronome / nfp / nfp_net_common.c

/*
 * Copyright (C) 2015 Netronome Systems, Inc.
 *
 * This software is dual licensed under the GNU General License Version 2,
 * June 1991 as shown in the file COPYING in the top-level directory of this
 * source tree or the BSD 2-Clause License provided below.  You have the
 * option to license this software under the complete terms of either license.
 *
 * The BSD 2-Clause License:
 *
 *     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.
 *
 * 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.
 */

/*
 * nfp_net_common.c
 * Netronome network device driver: Common functions between PF and VF
 * Authors: Jakub Kicinski <jakub.kicinski@netronome.com>
 *          Jason McMullan <jason.mcmullan@netronome.com>
 *          Rolf Neugebauer <rolf.neugebauer@netronome.com>
 *          Brad Petrus <brad.petrus@netronome.com>
 *          Chris Telfer <chris.telfer@netronome.com>
 */

#include <linux/version.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/interrupt.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/pci.h>
#include <linux/pci_regs.h>
#include <linux/msi.h>
#include <linux/ethtool.h>
#include <linux/log2.h>
#include <linux/if_vlan.h>
#include <linux/random.h>

#include <linux/ktime.h>

#include <net/vxlan.h>

#include "nfp_net_ctrl.h"
#include "nfp_net.h"

/**
 * nfp_net_get_fw_version() - Read and parse the FW version
 * @fw_ver:     Output fw_version structure to read to
 * @ctrl_bar:   Mapped address of the control BAR
 */
void nfp_net_get_fw_version(struct nfp_net_fw_version *fw_ver,
                            void __iomem *ctrl_bar)
{
        u32 reg;

        reg = readl(ctrl_bar + NFP_NET_CFG_VERSION);
        put_unaligned_le32(reg, fw_ver);
}

/* Firmware reconfig
 *
 * Firmware reconfig may take a while so we have two versions of it -
 * synchronous and asynchronous (posted).  All synchronous callers are holding
 * RTNL so we don't have to worry about serializing them.
 */
static void nfp_net_reconfig_start(struct nfp_net *nn, u32 update)
{
        nn_writel(nn, NFP_NET_CFG_UPDATE, update);
        /* ensure update is written before pinging HW */
        nn_pci_flush(nn);
        nfp_qcp_wr_ptr_add(nn->qcp_cfg, 1);
}

/* Pass 0 as update to run posted reconfigs. */
static void nfp_net_reconfig_start_async(struct nfp_net *nn, u32 update)
{
        update |= nn->reconfig_posted;
        nn->reconfig_posted = 0;

        nfp_net_reconfig_start(nn, update);

        nn->reconfig_timer_active = true;
        mod_timer(&nn->reconfig_timer, jiffies + NFP_NET_POLL_TIMEOUT * HZ);
}

static bool nfp_net_reconfig_check_done(struct nfp_net *nn, bool last_check)
{
        u32 reg;

        reg = nn_readl(nn, NFP_NET_CFG_UPDATE);
        if (reg == 0)
                return true;
        if (reg & NFP_NET_CFG_UPDATE_ERR) {
                nn_err(nn, "Reconfig error: 0x%08x\n", reg);
                return true;
        } else if (last_check) {
                nn_err(nn, "Reconfig timeout: 0x%08x\n", reg);
                return true;
        }

        return false;
}

static int nfp_net_reconfig_wait(struct nfp_net *nn, unsigned long deadline)
{
        bool timed_out = false;

        /* Poll update field, waiting for NFP to ack the config */
        while (!nfp_net_reconfig_check_done(nn, timed_out)) {
                msleep(1);
                timed_out = time_is_before_eq_jiffies(deadline);
        }

        if (nn_readl(nn, NFP_NET_CFG_UPDATE) & NFP_NET_CFG_UPDATE_ERR)
                return -EIO;

        return timed_out ? -EIO : 0;
}

static void nfp_net_reconfig_timer(unsigned long data)
{
        struct nfp_net *nn = (void *)data;

        spin_lock_bh(&nn->reconfig_lock);

        nn->reconfig_timer_active = false;

        /* If sync caller is present it will take over from us */
        if (nn->reconfig_sync_present)
                goto done;

        /* Read reconfig status and report errors */
        nfp_net_reconfig_check_done(nn, true);

        if (nn->reconfig_posted)
                nfp_net_reconfig_start_async(nn, 0);
done:
        spin_unlock_bh(&nn->reconfig_lock);
}

/**
 * nfp_net_reconfig_post() - Post async reconfig request
 * @nn:      NFP Net device to reconfigure
 * @update:  The value for the update field in the BAR config
 *
 * Record FW reconfiguration request.  Reconfiguration will be kicked off
 * whenever reconfiguration machinery is idle.  Multiple requests can be
 * merged together!
 */
static void nfp_net_reconfig_post(struct nfp_net *nn, u32 update)
{
        spin_lock_bh(&nn->reconfig_lock);

        /* Sync caller will kick off async reconf when it's done, just post */
        if (nn->reconfig_sync_present) {
                nn->reconfig_posted |= update;
                goto done;
        }

        /* Opportunistically check if the previous command is done */
        if (!nn->reconfig_timer_active ||
            nfp_net_reconfig_check_done(nn, false))
                nfp_net_reconfig_start_async(nn, update);
        else
                nn->reconfig_posted |= update;
done:
        spin_unlock_bh(&nn->reconfig_lock);
}

/**
 * nfp_net_reconfig() - Reconfigure the firmware
 * @nn:      NFP Net device to reconfigure
 * @update:  The value for the update field in the BAR config
 *
 * Write the update word to the BAR and ping the reconfig queue.  The
 * poll until the firmware has acknowledged the update by zeroing the
 * update word.
 *
 * Return: Negative errno on error, 0 on success
 */
int nfp_net_reconfig(struct nfp_net *nn, u32 update)
{
        bool cancelled_timer = false;
        u32 pre_posted_requests;
        int ret;

        spin_lock_bh(&nn->reconfig_lock);

        nn->reconfig_sync_present = true;

        if (nn->reconfig_timer_active) {
                del_timer(&nn->reconfig_timer);
                nn->reconfig_timer_active = false;
                cancelled_timer = true;
        }
        pre_posted_requests = nn->reconfig_posted;
        nn->reconfig_posted = 0;

        spin_unlock_bh(&nn->reconfig_lock);

        if (cancelled_timer)
                nfp_net_reconfig_wait(nn, nn->reconfig_timer.expires);

        /* Run the posted reconfigs which were issued before we started */
        if (pre_posted_requests) {
                nfp_net_reconfig_start(nn, pre_posted_requests);
                nfp_net_reconfig_wait(nn, jiffies + HZ * NFP_NET_POLL_TIMEOUT);
        }

        nfp_net_reconfig_start(nn, update);
        ret = nfp_net_reconfig_wait(nn, jiffies + HZ * NFP_NET_POLL_TIMEOUT);

        spin_lock_bh(&nn->reconfig_lock);

        if (nn->reconfig_posted)
                nfp_net_reconfig_start_async(nn, 0);

        nn->reconfig_sync_present = false;

        spin_unlock_bh(&nn->reconfig_lock);

        return ret;
}

/* Interrupt configuration and handling
 */

/**
 * nfp_net_irq_unmask_msix() - Unmask MSI-X after automasking
 * @nn:       NFP Network structure
 * @entry_nr: MSI-X table entry
 *
 * Clear the MSI-X table mask bit for the given entry bypassing Linux irq
 * handling subsystem.  Use *only* to reenable automasked vectors.
 */
static void nfp_net_irq_unmask_msix(struct nfp_net *nn, unsigned int entry_nr)
{
        struct list_head *msi_head = &nn->pdev->dev.msi_list;
        struct msi_desc *entry;
        u32 off;

        /* All MSI-Xs have the same mask_base */
        entry = list_first_entry(msi_head, struct msi_desc, list);

        off = (PCI_MSIX_ENTRY_SIZE * entry_nr) +
                PCI_MSIX_ENTRY_VECTOR_CTRL;
        writel(0, entry->mask_base + off);
        readl(entry->mask_base);
}

/**
 * nfp_net_irq_unmask() - Unmask automasked interrupt
 * @nn:       NFP Network structure
 * @entry_nr: MSI-X table entry
 *
 * If MSI-X auto-masking is enabled clear the mask bit, otherwise
 * clear the ICR for the entry.
 */
static void nfp_net_irq_unmask(struct nfp_net *nn, unsigned int entry_nr)
{
        if (nn->ctrl & NFP_NET_CFG_CTRL_MSIXAUTO) {
                nfp_net_irq_unmask_msix(nn, entry_nr);
                return;
        }

        nn_writeb(nn, NFP_NET_CFG_ICR(entry_nr), NFP_NET_CFG_ICR_UNMASKED);
        nn_pci_flush(nn);
}

/**
 * nfp_net_msix_alloc() - Try to allocate MSI-X irqs
 * @nn:       NFP Network structure
 * @nr_vecs:  Number of MSI-X vectors to allocate
 *
 * For MSI-X we want at least NFP_NET_NON_Q_VECTORS + 1 vectors.
 *
 * Return: Number of MSI-X vectors obtained or 0 on error.
 */
static int nfp_net_msix_alloc(struct nfp_net *nn, int nr_vecs)
{
        struct pci_dev *pdev = nn->pdev;
        int nvecs;
        int i;

        for (i = 0; i < nr_vecs; i++)
                nn->irq_entries[i].entry = i;

        nvecs = pci_enable_msix_range(pdev, nn->irq_entries,
                                      NFP_NET_NON_Q_VECTORS + 1, nr_vecs);
        if (nvecs < 0) {
                nn_warn(nn, "Failed to enable MSI-X. Wanted %d-%d (err=%d)\n",
                        NFP_NET_NON_Q_VECTORS + 1, nr_vecs, nvecs);
                return 0;
        }

        return nvecs;
}

/**
 * nfp_net_irqs_wanted() - Work out how many interrupt vectors we want
 * @nn:       NFP Network structure
 *
 * We want a vector per CPU (or ring), whatever is smaller plus
 * NFP_NET_NON_Q_VECTORS for LSC etc.
 *
 * Return: Number of interrupts wanted
 */
static int nfp_net_irqs_wanted(struct nfp_net *nn)
{
        int ncpus;
        int vecs;

        ncpus = num_online_cpus();

        vecs = max_t(int, nn->num_tx_rings, nn->num_rx_rings);
        vecs = min_t(int, vecs, ncpus);

        return vecs + NFP_NET_NON_Q_VECTORS;
}

/**
 * nfp_net_irqs_alloc() - allocates MSI-X irqs
 * @nn:       NFP Network structure
 *
 * Return: Number of irqs obtained or 0 on error.
 */
int nfp_net_irqs_alloc(struct nfp_net *nn)
{
        int wanted_irqs;

        wanted_irqs = nfp_net_irqs_wanted(nn);

        nn->num_irqs = nfp_net_msix_alloc(nn, wanted_irqs);
        if (nn->num_irqs == 0) {
                nn_err(nn, "Failed to allocate MSI-X IRQs\n");
                return 0;
        }

        nn->num_r_vecs = nn->num_irqs - NFP_NET_NON_Q_VECTORS;

        if (nn->num_irqs < wanted_irqs)
                nn_warn(nn, "Unable to allocate %d vectors. Got %d instead\n",
                        wanted_irqs, nn->num_irqs);

        return nn->num_irqs;
}

/**
 * nfp_net_irqs_disable() - Disable interrupts
 * @nn:       NFP Network structure
 *
 * Undoes what @nfp_net_irqs_alloc() does.
 */
void nfp_net_irqs_disable(struct nfp_net *nn)
{
        pci_disable_msix(nn->pdev);
}

/**
 * nfp_net_irq_rxtx() - Interrupt service routine for RX/TX rings.
 * @irq:      Interrupt
 * @data:     Opaque data structure
 *
 * Return: Indicate if the interrupt has been handled.
 */
static irqreturn_t nfp_net_irq_rxtx(int irq, void *data)
{
        struct nfp_net_r_vector *r_vec = data;

        napi_schedule_irqoff(&r_vec->napi);

        /* The FW auto-masks any interrupt, either via the MASK bit in
         * the MSI-X table or via the per entry ICR field.  So there
         * is no need to disable interrupts here.
         */
        return IRQ_HANDLED;
}

/**
 * nfp_net_read_link_status() - Reread link status from control BAR
 * @nn:       NFP Network structure
 */
static void nfp_net_read_link_status(struct nfp_net *nn)
{
        unsigned long flags;
        bool link_up;
        u32 sts;

        spin_lock_irqsave(&nn->link_status_lock, flags);

        sts = nn_readl(nn, NFP_NET_CFG_STS);
        link_up = !!(sts & NFP_NET_CFG_STS_LINK);

        if (nn->link_up == link_up)
                goto out;

        nn->link_up = link_up;

        if (nn->link_up) {
                netif_carrier_on(nn->netdev);
                netdev_info(nn->netdev, "NIC Link is Up\n");
        } else {
                netif_carrier_off(nn->netdev);
                netdev_info(nn->netdev, "NIC Link is Down\n");
        }
out:
        spin_unlock_irqrestore(&nn->link_status_lock, flags);
}

/**
 * nfp_net_irq_lsc() - Interrupt service routine for link state changes
 * @irq:      Interrupt
 * @data:     Opaque data structure
 *
 * Return: Indicate if the interrupt has been handled.
 */
static irqreturn_t nfp_net_irq_lsc(int irq, void *data)
{
        struct nfp_net *nn = data;

        nfp_net_read_link_status(nn);

        nfp_net_irq_unmask(nn, NFP_NET_IRQ_LSC_IDX);

        return IRQ_HANDLED;
}

/**
 * nfp_net_irq_exn() - Interrupt service routine for exceptions
 * @irq:      Interrupt
 * @data:     Opaque data structure
 *
 * Return: Indicate if the interrupt has been handled.
 */
static irqreturn_t nfp_net_irq_exn(int irq, void *data)
{
        struct nfp_net *nn = data;

        nn_err(nn, "%s: UNIMPLEMENTED.\n", __func__);
        /* XXX TO BE IMPLEMENTED */
        return IRQ_HANDLED;
}

/**
 * nfp_net_tx_ring_init() - Fill in the boilerplate for a TX ring
 * @tx_ring:  TX ring structure
 * @r_vec:    IRQ vector servicing this ring
 * @idx:      Ring index
 */
static void
nfp_net_tx_ring_init(struct nfp_net_tx_ring *tx_ring,
                     struct nfp_net_r_vector *r_vec, unsigned int idx)
{
        struct nfp_net *nn = r_vec->nfp_net;

        tx_ring->idx = idx;
        tx_ring->r_vec = r_vec;

        tx_ring->qcidx = tx_ring->idx * nn->stride_tx;
        tx_ring->qcp_q = nn->tx_bar + NFP_QCP_QUEUE_OFF(tx_ring->qcidx);
}

/**
 * nfp_net_rx_ring_init() - Fill in the boilerplate for a RX ring
 * @rx_ring:  RX ring structure
 * @r_vec:    IRQ vector servicing this ring
 * @idx:      Ring index
 */
static void
nfp_net_rx_ring_init(struct nfp_net_rx_ring *rx_ring,
                     struct nfp_net_r_vector *r_vec, unsigned int idx)
{
        struct nfp_net *nn = r_vec->nfp_net;

        rx_ring->idx = idx;
        rx_ring->r_vec = r_vec;

        rx_ring->fl_qcidx = rx_ring->idx * nn->stride_rx;
        rx_ring->rx_qcidx = rx_ring->fl_qcidx + (nn->stride_rx - 1);

        rx_ring->qcp_fl = nn->rx_bar + NFP_QCP_QUEUE_OFF(rx_ring->fl_qcidx);
        rx_ring->qcp_rx = nn->rx_bar + NFP_QCP_QUEUE_OFF(rx_ring->rx_qcidx);
}

/**
 * nfp_net_irqs_assign() - Assign IRQs and setup rvecs.
 * @netdev:   netdev structure
 */
static void nfp_net_irqs_assign(struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);
        struct nfp_net_r_vector *r_vec;
        int r;

        /* Assumes nn->num_tx_rings == nn->num_rx_rings */
        if (nn->num_tx_rings > nn->num_r_vecs) {
                nn_warn(nn, "More rings (%d) than vectors (%d).\n",
                        nn->num_tx_rings, nn->num_r_vecs);
                nn->num_tx_rings = nn->num_r_vecs;
                nn->num_rx_rings = nn->num_r_vecs;
        }

        nn->lsc_handler = nfp_net_irq_lsc;
        nn->exn_handler = nfp_net_irq_exn;

        for (r = 0; r < nn->num_r_vecs; r++) {
                r_vec = &nn->r_vecs[r];
                r_vec->nfp_net = nn;
                r_vec->handler = nfp_net_irq_rxtx;
                r_vec->irq_idx = NFP_NET_NON_Q_VECTORS + r;

                cpumask_set_cpu(r, &r_vec->affinity_mask);
        }
}

/**
 * nfp_net_aux_irq_request() - Request an auxiliary interrupt (LSC or EXN)
 * @nn:         NFP Network structure
 * @ctrl_offset: Control BAR offset where IRQ configuration should be written
 * @format:     printf-style format to construct the interrupt name
 * @name:       Pointer to allocated space for interrupt name
 * @name_sz:    Size of space for interrupt name
 * @vector_idx: Index of MSI-X vector used for this interrupt
 * @handler:    IRQ handler to register for this interrupt
 */
static int
nfp_net_aux_irq_request(struct nfp_net *nn, u32 ctrl_offset,
                        const char *format, char *name, size_t name_sz,
                        unsigned int vector_idx, irq_handler_t handler)
{
        struct msix_entry *entry;
        int err;

        entry = &nn->irq_entries[vector_idx];

        snprintf(name, name_sz, format, netdev_name(nn->netdev));
        err = request_irq(entry->vector, handler, 0, name, nn);
        if (err) {
                nn_err(nn, "Failed to request IRQ %d (err=%d).\n",
                       entry->vector, err);
                return err;
        }
        nn_writeb(nn, ctrl_offset, vector_idx);

        return 0;
}

/**
 * nfp_net_aux_irq_free() - Free an auxiliary interrupt (LSC or EXN)
 * @nn:         NFP Network structure
 * @ctrl_offset: Control BAR offset where IRQ configuration should be written
 * @vector_idx: Index of MSI-X vector used for this interrupt
 */
static void nfp_net_aux_irq_free(struct nfp_net *nn, u32 ctrl_offset,
                                 unsigned int vector_idx)
{
        nn_writeb(nn, ctrl_offset, 0xff);
        free_irq(nn->irq_entries[vector_idx].vector, nn);
}

/* Transmit
 *
 * One queue controller peripheral queue is used for transmit.  The
 * driver en-queues packets for transmit by advancing the write
 * pointer.  The device indicates that packets have transmitted by
 * advancing the read pointer.  The driver maintains a local copy of
 * the read and write pointer in @struct nfp_net_tx_ring.  The driver
 * keeps @wr_p in sync with the queue controller write pointer and can
 * determine how many packets have been transmitted by comparing its
 * copy of the read pointer @rd_p with the read pointer maintained by
 * the queue controller peripheral.
 */

/**
 * nfp_net_tx_full() - Check if the TX ring is full
 * @tx_ring: TX ring to check
 * @dcnt:    Number of descriptors that need to be enqueued (must be >= 1)
 *
 * This function checks, based on the *host copy* of read/write
 * pointer if a given TX ring is full.  The real TX queue may have
 * some newly made available slots.
 *
 * Return: True if the ring is full.
 */
static inline int nfp_net_tx_full(struct nfp_net_tx_ring *tx_ring, int dcnt)
{
        return (tx_ring->wr_p - tx_ring->rd_p) >= (tx_ring->cnt - dcnt);
}

/* Wrappers for deciding when to stop and restart TX queues */
static int nfp_net_tx_ring_should_wake(struct nfp_net_tx_ring *tx_ring)
{
        return !nfp_net_tx_full(tx_ring, MAX_SKB_FRAGS * 4);
}

static int nfp_net_tx_ring_should_stop(struct nfp_net_tx_ring *tx_ring)
{
        return nfp_net_tx_full(tx_ring, MAX_SKB_FRAGS + 1);
}

/**
 * nfp_net_tx_ring_stop() - stop tx ring
 * @nd_q:    netdev queue
 * @tx_ring: driver tx queue structure
 *
 * Safely stop TX ring.  Remember that while we are running .start_xmit()
 * someone else may be cleaning the TX ring completions so we need to be
 * extra careful here.
 */
static void nfp_net_tx_ring_stop(struct netdev_queue *nd_q,
                                 struct nfp_net_tx_ring *tx_ring)
{
        netif_tx_stop_queue(nd_q);

        /* We can race with the TX completion out of NAPI so recheck */
        smp_mb();
        if (unlikely(nfp_net_tx_ring_should_wake(tx_ring)))
                netif_tx_start_queue(nd_q);
}

/**
 * nfp_net_tx_tso() - Set up Tx descriptor for LSO
 * @nn:  NFP Net device
 * @r_vec: per-ring structure
 * @txbuf: Pointer to driver soft TX descriptor
 * @txd: Pointer to HW TX descriptor
 * @skb: Pointer to SKB
 *
 * Set up Tx descriptor for LSO, do nothing for non-LSO skbs.
 * Return error on packet header greater than maximum supported LSO header size.
 */
static void nfp_net_tx_tso(struct nfp_net *nn, struct nfp_net_r_vector *r_vec,
                           struct nfp_net_tx_buf *txbuf,
                           struct nfp_net_tx_desc *txd, struct sk_buff *skb)
{
        u32 hdrlen;
        u16 mss;

        if (!skb_is_gso(skb))
                return;

        if (!skb->encapsulation)
                hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
        else
                hdrlen = skb_inner_transport_header(skb) - skb->data +
                        inner_tcp_hdrlen(skb);

        txbuf->pkt_cnt = skb_shinfo(skb)->gso_segs;
        txbuf->real_len += hdrlen * (txbuf->pkt_cnt - 1);

        mss = skb_shinfo(skb)->gso_size & PCIE_DESC_TX_MSS_MASK;
        txd->l4_offset = hdrlen;
        txd->mss = cpu_to_le16(mss);
        txd->flags |= PCIE_DESC_TX_LSO;

        u64_stats_update_begin(&r_vec->tx_sync);
        r_vec->tx_lso++;
        u64_stats_update_end(&r_vec->tx_sync);
}

/**
 * nfp_net_tx_csum() - Set TX CSUM offload flags in TX descriptor
 * @nn:  NFP Net device
 * @r_vec: per-ring structure
 * @txbuf: Pointer to driver soft TX descriptor
 * @txd: Pointer to TX descriptor
 * @skb: Pointer to SKB
 *
 * This function sets the TX checksum flags in the TX descriptor based
 * on the configuration and the protocol of the packet to be transmitted.
 */
static void nfp_net_tx_csum(struct nfp_net *nn, struct nfp_net_r_vector *r_vec,
                            struct nfp_net_tx_buf *txbuf,
                            struct nfp_net_tx_desc *txd, struct sk_buff *skb)
{
        struct ipv6hdr *ipv6h;
        struct iphdr *iph;
        u8 l4_hdr;

        if (!(nn->ctrl & NFP_NET_CFG_CTRL_TXCSUM))
                return;

        if (skb->ip_summed != CHECKSUM_PARTIAL)
                return;

        txd->flags |= PCIE_DESC_TX_CSUM;
        if (skb->encapsulation)
                txd->flags |= PCIE_DESC_TX_ENCAP;

        iph = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
        ipv6h = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);

        if (iph->version == 4) {
                txd->flags |= PCIE_DESC_TX_IP4_CSUM;
                l4_hdr = iph->protocol;
        } else if (ipv6h->version == 6) {
                l4_hdr = ipv6h->nexthdr;
        } else {
                nn_warn_ratelimit(nn, "partial checksum but ipv=%x!\n",
                                  iph->version);
                return;
        }

        switch (l4_hdr) {
        case IPPROTO_TCP:
                txd->flags |= PCIE_DESC_TX_TCP_CSUM;
                break;
        case IPPROTO_UDP:
                txd->flags |= PCIE_DESC_TX_UDP_CSUM;
                break;
        default:
                nn_warn_ratelimit(nn, "partial checksum but l4 proto=%x!\n",
                                  l4_hdr);
                return;
        }

        u64_stats_update_begin(&r_vec->tx_sync);
        if (skb->encapsulation)
                r_vec->hw_csum_tx_inner += txbuf->pkt_cnt;
        else
                r_vec->hw_csum_tx += txbuf->pkt_cnt;
        u64_stats_update_end(&r_vec->tx_sync);
}

/**
 * nfp_net_tx() - Main transmit entry point
 * @skb:    SKB to transmit
 * @netdev: netdev structure
 *
 * Return: NETDEV_TX_OK on success.
 */
static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);
        const struct skb_frag_struct *frag;
        struct nfp_net_r_vector *r_vec;
        struct nfp_net_tx_desc *txd, txdg;
        struct nfp_net_tx_buf *txbuf;
        struct nfp_net_tx_ring *tx_ring;
        struct netdev_queue *nd_q;
        dma_addr_t dma_addr;
        unsigned int fsize;
        int f, nr_frags;
        int wr_idx;
        u16 qidx;

        qidx = skb_get_queue_mapping(skb);
        tx_ring = &nn->tx_rings[qidx];
        r_vec = tx_ring->r_vec;
        nd_q = netdev_get_tx_queue(nn->netdev, qidx);

        nr_frags = skb_shinfo(skb)->nr_frags;

        if (unlikely(nfp_net_tx_full(tx_ring, nr_frags + 1))) {
                nn_warn_ratelimit(nn, "TX ring %d busy. wrp=%u rdp=%u\n",
                                  qidx, tx_ring->wr_p, tx_ring->rd_p);
                netif_tx_stop_queue(nd_q);
                u64_stats_update_begin(&r_vec->tx_sync);
                r_vec->tx_busy++;
                u64_stats_update_end(&r_vec->tx_sync);
                return NETDEV_TX_BUSY;
        }

        /* Start with the head skbuf */
        dma_addr = dma_map_single(&nn->pdev->dev, skb->data, skb_headlen(skb),
                                  DMA_TO_DEVICE);
        if (dma_mapping_error(&nn->pdev->dev, dma_addr))
                goto err_free;

        wr_idx = tx_ring->wr_p % tx_ring->cnt;

        /* Stash the soft descriptor of the head then initialize it */
        txbuf = &tx_ring->txbufs[wr_idx];
        txbuf->skb = skb;
        txbuf->dma_addr = dma_addr;
        txbuf->fidx = -1;
        txbuf->pkt_cnt = 1;
        txbuf->real_len = skb->len;

        /* Build TX descriptor */
        txd = &tx_ring->txds[wr_idx];
        txd->offset_eop = (nr_frags == 0) ? PCIE_DESC_TX_EOP : 0;
        txd->dma_len = cpu_to_le16(skb_headlen(skb));
        nfp_desc_set_dma_addr(txd, dma_addr);
        txd->data_len = cpu_to_le16(skb->len);

        txd->flags = 0;
        txd->mss = 0;
        txd->l4_offset = 0;

        nfp_net_tx_tso(nn, r_vec, txbuf, txd, skb);

        nfp_net_tx_csum(nn, r_vec, txbuf, txd, skb);

        if (skb_vlan_tag_present(skb) && nn->ctrl & NFP_NET_CFG_CTRL_TXVLAN) {
                txd->flags |= PCIE_DESC_TX_VLAN;
                txd->vlan = cpu_to_le16(skb_vlan_tag_get(skb));
        }

        /* Gather DMA */
        if (nr_frags > 0) {
                /* all descs must match except for in addr, length and eop */
                txdg = *txd;

                for (f = 0; f < nr_frags; f++) {
                        frag = &skb_shinfo(skb)->frags[f];
                        fsize = skb_frag_size(frag);

                        dma_addr = skb_frag_dma_map(&nn->pdev->dev, frag, 0,
                                                    fsize, DMA_TO_DEVICE);
                        if (dma_mapping_error(&nn->pdev->dev, dma_addr))
                                goto err_unmap;

                        wr_idx = (wr_idx + 1) % tx_ring->cnt;
                        tx_ring->txbufs[wr_idx].skb = skb;
                        tx_ring->txbufs[wr_idx].dma_addr = dma_addr;
                        tx_ring->txbufs[wr_idx].fidx = f;

                        txd = &tx_ring->txds[wr_idx];
                        *txd = txdg;
                        txd->dma_len = cpu_to_le16(fsize);
                        nfp_desc_set_dma_addr(txd, dma_addr);
                        txd->offset_eop =
                                (f == nr_frags - 1) ? PCIE_DESC_TX_EOP : 0;
                }

                u64_stats_update_begin(&r_vec->tx_sync);
                r_vec->tx_gather++;
                u64_stats_update_end(&r_vec->tx_sync);
        }

        netdev_tx_sent_queue(nd_q, txbuf->real_len);

        tx_ring->wr_p += nr_frags + 1;
        if (nfp_net_tx_ring_should_stop(tx_ring))
                nfp_net_tx_ring_stop(nd_q, tx_ring);

        tx_ring->wr_ptr_add += nr_frags + 1;
        if (!skb->xmit_more || netif_xmit_stopped(nd_q)) {
                /* force memory write before we let HW know */
                wmb();
                nfp_qcp_wr_ptr_add(tx_ring->qcp_q, tx_ring->wr_ptr_add);
                tx_ring->wr_ptr_add = 0;
        }

        skb_tx_timestamp(skb);

        return NETDEV_TX_OK;

err_unmap:
        --f;
        while (f >= 0) {
                frag = &skb_shinfo(skb)->frags[f];
                dma_unmap_page(&nn->pdev->dev,
                               tx_ring->txbufs[wr_idx].dma_addr,
                               skb_frag_size(frag), DMA_TO_DEVICE);
                tx_ring->txbufs[wr_idx].skb = NULL;
                tx_ring->txbufs[wr_idx].dma_addr = 0;
                tx_ring->txbufs[wr_idx].fidx = -2;
                wr_idx = wr_idx - 1;
                if (wr_idx < 0)
                        wr_idx += tx_ring->cnt;
        }
        dma_unmap_single(&nn->pdev->dev, tx_ring->txbufs[wr_idx].dma_addr,
                         skb_headlen(skb), DMA_TO_DEVICE);
        tx_ring->txbufs[wr_idx].skb = NULL;
        tx_ring->txbufs[wr_idx].dma_addr = 0;
        tx_ring->txbufs[wr_idx].fidx = -2;
err_free:
        nn_warn_ratelimit(nn, "Failed to map DMA TX buffer\n");
        u64_stats_update_begin(&r_vec->tx_sync);
        r_vec->tx_errors++;
        u64_stats_update_end(&r_vec->tx_sync);
        dev_kfree_skb_any(skb);
        return NETDEV_TX_OK;
}

/**
 * nfp_net_tx_complete() - Handled completed TX packets
 * @tx_ring:   TX ring structure
 *
 * Return: Number of completed TX descriptors
 */
static void nfp_net_tx_complete(struct nfp_net_tx_ring *tx_ring)
{
        struct nfp_net_r_vector *r_vec = tx_ring->r_vec;
        struct nfp_net *nn = r_vec->nfp_net;
        const struct skb_frag_struct *frag;
        struct netdev_queue *nd_q;
        u32 done_pkts = 0, done_bytes = 0;
        struct sk_buff *skb;
        int todo, nr_frags;
        u32 qcp_rd_p;
        int fidx;
        int idx;

        /* 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;

        if (qcp_rd_p > tx_ring->qcp_rd_p)
                todo = qcp_rd_p - tx_ring->qcp_rd_p;
        else
                todo = qcp_rd_p + tx_ring->cnt - tx_ring->qcp_rd_p;

        while (todo--) {
                idx = tx_ring->rd_p % tx_ring->cnt;
                tx_ring->rd_p++;

                skb = tx_ring->txbufs[idx].skb;
                if (!skb)
                        continue;

                nr_frags = skb_shinfo(skb)->nr_frags;
                fidx = tx_ring->txbufs[idx].fidx;

                if (fidx == -1) {
                        /* unmap head */
                        dma_unmap_single(&nn->pdev->dev,
                                         tx_ring->txbufs[idx].dma_addr,
                                         skb_headlen(skb), DMA_TO_DEVICE);

                        done_pkts += tx_ring->txbufs[idx].pkt_cnt;
                        done_bytes += tx_ring->txbufs[idx].real_len;
                } else {
                        /* unmap fragment */
                        frag = &skb_shinfo(skb)->frags[fidx];
                        dma_unmap_page(&nn->pdev->dev,
                                       tx_ring->txbufs[idx].dma_addr,
                                       skb_frag_size(frag), DMA_TO_DEVICE);
                }

                /* check for last gather fragment */
                if (fidx == nr_frags - 1)
                        dev_kfree_skb_any(skb);

                tx_ring->txbufs[idx].dma_addr = 0;
                tx_ring->txbufs[idx].skb = NULL;
                tx_ring->txbufs[idx].fidx = -2;
        }

        tx_ring->qcp_rd_p = qcp_rd_p;

        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);

        nd_q = netdev_get_tx_queue(nn->netdev, tx_ring->idx);
        netdev_tx_completed_queue(nd_q, done_pkts, done_bytes);
        if (nfp_net_tx_ring_should_wake(tx_ring)) {
                /* Make sure TX thread will see updated tx_ring->rd_p */
                smp_mb();

                if (unlikely(netif_tx_queue_stopped(nd_q)))
                        netif_tx_wake_queue(nd_q);
        }

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

/**
 * nfp_net_tx_ring_reset() - Free any untransmitted buffers and reset pointers
 * @nn:         NFP Net device
 * @tx_ring:    TX ring structure
 *
 * Assumes that the device is stopped
 */
static void
nfp_net_tx_ring_reset(struct nfp_net *nn, struct nfp_net_tx_ring *tx_ring)
{
        const struct skb_frag_struct *frag;
        struct netdev_queue *nd_q;
        struct pci_dev *pdev = nn->pdev;

        while (tx_ring->rd_p != tx_ring->wr_p) {
                int nr_frags, fidx, idx;
                struct sk_buff *skb;

                idx = tx_ring->rd_p % tx_ring->cnt;
                skb = tx_ring->txbufs[idx].skb;
                nr_frags = skb_shinfo(skb)->nr_frags;
                fidx = tx_ring->txbufs[idx].fidx;

                if (fidx == -1) {
                        /* unmap head */
                        dma_unmap_single(&pdev->dev,
                                         tx_ring->txbufs[idx].dma_addr,
                                         skb_headlen(skb), DMA_TO_DEVICE);
                } else {
                        /* unmap fragment */
                        frag = &skb_shinfo(skb)->frags[fidx];
                        dma_unmap_page(&pdev->dev,
                                       tx_ring->txbufs[idx].dma_addr,
                                       skb_frag_size(frag), DMA_TO_DEVICE);
                }

                /* check for last gather fragment */
                if (fidx == nr_frags - 1)
                        dev_kfree_skb_any(skb);

                tx_ring->txbufs[idx].dma_addr = 0;
                tx_ring->txbufs[idx].skb = NULL;
                tx_ring->txbufs[idx].fidx = -2;

                tx_ring->qcp_rd_p++;
                tx_ring->rd_p++;
        }

        memset(tx_ring->txds, 0, sizeof(*tx_ring->txds) * tx_ring->cnt);
        tx_ring->wr_p = 0;
        tx_ring->rd_p = 0;
        tx_ring->qcp_rd_p = 0;
        tx_ring->wr_ptr_add = 0;

        nd_q = netdev_get_tx_queue(nn->netdev, tx_ring->idx);
        netdev_tx_reset_queue(nd_q);
}

static void nfp_net_tx_timeout(struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);
        int i;

        for (i = 0; i < nn->num_tx_rings; i++) {
                if (!netif_tx_queue_stopped(netdev_get_tx_queue(netdev, i)))
                        continue;
                nn_warn(nn, "TX timeout on ring: %d\n", i);
        }
        nn_warn(nn, "TX watchdog timeout\n");
}

/* Receive processing
 */

/**
 * nfp_net_rx_space() - return the number of free slots on the RX ring
 * @rx_ring:   RX ring structure
 *
 * Make sure we leave at least one slot free.
 *
 * Return: True if there is space on the RX ring
 */
static inline int nfp_net_rx_space(struct nfp_net_rx_ring *rx_ring)
{
        return (rx_ring->cnt - 1) - (rx_ring->wr_p - rx_ring->rd_p);
}

/**
 * nfp_net_rx_alloc_one() - Allocate and map skb for RX
 * @rx_ring:    RX ring structure of the skb
 * @dma_addr:   Pointer to storage for DMA address (output param)
 * @fl_bufsz:   size of freelist buffers
 *
 * This function will allcate a new skb, map it for DMA.
 *
 * Return: allocated skb or NULL on failure.
 */
static struct sk_buff *
nfp_net_rx_alloc_one(struct nfp_net_rx_ring *rx_ring, dma_addr_t *dma_addr,
                     unsigned int fl_bufsz)
{
        struct nfp_net *nn = rx_ring->r_vec->nfp_net;
        struct sk_buff *skb;

        skb = netdev_alloc_skb(nn->netdev, fl_bufsz);
        if (!skb) {
                nn_warn_ratelimit(nn, "Failed to alloc receive SKB\n");
                return NULL;
        }

        *dma_addr = dma_map_single(&nn->pdev->dev, skb->data,
                                   fl_bufsz, DMA_FROM_DEVICE);
        if (dma_mapping_error(&nn->pdev->dev, *dma_addr)) {
                dev_kfree_skb_any(skb);
                nn_warn_ratelimit(nn, "Failed to map DMA RX buffer\n");
                return NULL;
        }

        return skb;
}

/**
 * nfp_net_rx_give_one() - Put mapped skb on the software and hardware rings
 * @rx_ring:    RX ring structure
 * @skb:        Skb to put on rings
 * @dma_addr:   DMA address of skb mapping
 */
static void nfp_net_rx_give_one(struct nfp_net_rx_ring *rx_ring,
                                struct sk_buff *skb, dma_addr_t dma_addr)
{
        unsigned int wr_idx;

        wr_idx = rx_ring->wr_p % rx_ring->cnt;

        /* Stash SKB and DMA address away */
        rx_ring->rxbufs[wr_idx].skb = skb;
        rx_ring->rxbufs[wr_idx].dma_addr = dma_addr;

        /* Fill freelist descriptor */
        rx_ring->rxds[wr_idx].fld.reserved = 0;
        rx_ring->rxds[wr_idx].fld.meta_len_dd = 0;
        nfp_desc_set_dma_addr(&rx_ring->rxds[wr_idx].fld, dma_addr);

        rx_ring->wr_p++;
        rx_ring->wr_ptr_add++;
        if (rx_ring->wr_ptr_add >= NFP_NET_FL_BATCH) {
                /* Update write pointer of the freelist queue. Make
                 * sure all writes are flushed before telling the hardware.
                 */
                wmb();
                nfp_qcp_wr_ptr_add(rx_ring->qcp_fl, rx_ring->wr_ptr_add);
                rx_ring->wr_ptr_add = 0;
        }
}

/**
 * nfp_net_rx_ring_reset() - Reflect in SW state of freelist after disable
 * @rx_ring:    RX ring structure
 *
 * Warning: Do *not* call if ring buffers were never put on the FW freelist
 *          (i.e. device was not enabled)!
 */
static void nfp_net_rx_ring_reset(struct nfp_net_rx_ring *rx_ring)
{
        unsigned int wr_idx, last_idx;

        /* Move the empty entry to the end of the list */
        wr_idx = rx_ring->wr_p % rx_ring->cnt;
        last_idx = rx_ring->cnt - 1;
        rx_ring->rxbufs[wr_idx].dma_addr = rx_ring->rxbufs[last_idx].dma_addr;
        rx_ring->rxbufs[wr_idx].skb = rx_ring->rxbufs[last_idx].skb;
        rx_ring->rxbufs[last_idx].dma_addr = 0;
        rx_ring->rxbufs[last_idx].skb = NULL;

        memset(rx_ring->rxds, 0, sizeof(*rx_ring->rxds) * rx_ring->cnt);
        rx_ring->wr_p = 0;
        rx_ring->rd_p = 0;
        rx_ring->wr_ptr_add = 0;
}

/**
 * nfp_net_rx_ring_bufs_free() - Free any buffers currently on the RX ring
 * @nn:         NFP Net device
 * @rx_ring:    RX ring to remove buffers from
 *
 * Assumes that the device is stopped and buffers are in [0, ring->cnt - 1)
 * entries.  After device is disabled nfp_net_rx_ring_reset() must be called
 * to restore required ring geometry.
 */
static void
nfp_net_rx_ring_bufs_free(struct nfp_net *nn, struct nfp_net_rx_ring *rx_ring)
{
        struct pci_dev *pdev = nn->pdev;
        unsigned int i;

        for (i = 0; i < rx_ring->cnt - 1; i++) {
                /* NULL skb can only happen when initial filling of the ring
                 * fails to allocate enough buffers and calls here to free
                 * already allocated ones.
                 */
                if (!rx_ring->rxbufs[i].skb)
                        continue;

                dma_unmap_single(&pdev->dev, rx_ring->rxbufs[i].dma_addr,
                                 rx_ring->bufsz, DMA_FROM_DEVICE);
                dev_kfree_skb_any(rx_ring->rxbufs[i].skb);
                rx_ring->rxbufs[i].dma_addr = 0;
                rx_ring->rxbufs[i].skb = NULL;
        }
}

/**
 * nfp_net_rx_ring_bufs_alloc() - Fill RX ring with buffers (don't give to FW)
 * @nn:         NFP Net device
 * @rx_ring:    RX ring to remove buffers from
 */
static int
nfp_net_rx_ring_bufs_alloc(struct nfp_net *nn, struct nfp_net_rx_ring *rx_ring)
{
        struct nfp_net_rx_buf *rxbufs;
        unsigned int i;

        rxbufs = rx_ring->rxbufs;

        for (i = 0; i < rx_ring->cnt - 1; i++) {
                rxbufs[i].skb =
                        nfp_net_rx_alloc_one(rx_ring, &rxbufs[i].dma_addr,
                                             rx_ring->bufsz);
                if (!rxbufs[i].skb) {
                        nfp_net_rx_ring_bufs_free(nn, rx_ring);
                        return -ENOMEM;
                }
        }

        return 0;
}

/**
 * nfp_net_rx_ring_fill_freelist() - Give buffers from the ring to FW
 * @rx_ring: RX ring to fill
 */
static void nfp_net_rx_ring_fill_freelist(struct nfp_net_rx_ring *rx_ring)
{
        unsigned int i;

        for (i = 0; i < rx_ring->cnt - 1; i++)
                nfp_net_rx_give_one(rx_ring, rx_ring->rxbufs[i].skb,
                                    rx_ring->rxbufs[i].dma_addr);
}

/**
 * nfp_net_rx_csum_has_errors() - group check if rxd has any csum errors
 * @flags: RX descriptor flags field in CPU byte order
 */
static int nfp_net_rx_csum_has_errors(u16 flags)
{
        u16 csum_all_checked, csum_all_ok;

        csum_all_checked = flags & __PCIE_DESC_RX_CSUM_ALL;
        csum_all_ok = flags & __PCIE_DESC_RX_CSUM_ALL_OK;

        return csum_all_checked != (csum_all_ok << PCIE_DESC_RX_CSUM_OK_SHIFT);
}

/**
 * nfp_net_rx_csum() - set SKB checksum field based on RX descriptor flags
 * @nn:  NFP Net device
 * @r_vec: per-ring structure
 * @rxd: Pointer to RX descriptor
 * @skb: Pointer to SKB
 */
static void nfp_net_rx_csum(struct nfp_net *nn, struct nfp_net_r_vector *r_vec,
                            struct nfp_net_rx_desc *rxd, struct sk_buff *skb)
{
        skb_checksum_none_assert(skb);

        if (!(nn->netdev->features & NETIF_F_RXCSUM))
                return;

        if (nfp_net_rx_csum_has_errors(le16_to_cpu(rxd->rxd.flags))) {
                u64_stats_update_begin(&r_vec->rx_sync);
                r_vec->hw_csum_rx_error++;
                u64_stats_update_end(&r_vec->rx_sync);
                return;
        }

        /* Assume that the firmware will never report inner CSUM_OK unless outer
         * L4 headers were successfully parsed. FW will always report zero UDP
         * checksum as CSUM_OK.
         */
        if (rxd->rxd.flags & PCIE_DESC_RX_TCP_CSUM_OK ||
            rxd->rxd.flags & PCIE_DESC_RX_UDP_CSUM_OK) {
                __skb_incr_checksum_unnecessary(skb);
                u64_stats_update_begin(&r_vec->rx_sync);
                r_vec->hw_csum_rx_ok++;
                u64_stats_update_end(&r_vec->rx_sync);
        }

        if (rxd->rxd.flags & PCIE_DESC_RX_I_TCP_CSUM_OK ||
            rxd->rxd.flags & PCIE_DESC_RX_I_UDP_CSUM_OK) {
                __skb_incr_checksum_unnecessary(skb);
                u64_stats_update_begin(&r_vec->rx_sync);
                r_vec->hw_csum_rx_inner_ok++;
                u64_stats_update_end(&r_vec->rx_sync);
        }
}

/**
 * nfp_net_set_hash() - Set SKB hash data
 * @netdev: adapter's net_device structure
 * @skb:   SKB to set the hash data on
 * @rxd:   RX descriptor
 *
 * The RSS hash and hash-type are pre-pended to the packet data.
 * Extract and decode it and set the skb fields.
 */
static void nfp_net_set_hash(struct net_device *netdev, struct sk_buff *skb,
                             struct nfp_net_rx_desc *rxd)
{
        struct nfp_net_rx_hash *rx_hash;

        if (!(rxd->rxd.flags & PCIE_DESC_RX_RSS) ||
            !(netdev->features & NETIF_F_RXHASH))
                return;

        rx_hash = (struct nfp_net_rx_hash *)(skb->data - sizeof(*rx_hash));

        switch (be32_to_cpu(rx_hash->hash_type)) {
        case NFP_NET_RSS_IPV4:
        case NFP_NET_RSS_IPV6:
        case NFP_NET_RSS_IPV6_EX:
                skb_set_hash(skb, be32_to_cpu(rx_hash->hash), PKT_HASH_TYPE_L3);
                break;
        default:
                skb_set_hash(skb, be32_to_cpu(rx_hash->hash), PKT_HASH_TYPE_L4);
                break;
        }
}

/**
 * nfp_net_rx() - receive up to @budget packets on @rx_ring
 * @rx_ring:   RX ring to receive from
 * @budget:    NAPI budget
 *
 * Note, this function is separated out from the napi poll function to
 * more cleanly separate packet receive code from other bookkeeping
 * functions performed in the napi poll function.
 *
 * There are differences between the NFP-3200 firmware and the
 * NFP-6000 firmware.  The NFP-3200 firmware uses a dedicated RX queue
 * to indicate that new packets have arrived.  The NFP-6000 does not
 * have this queue and uses the DD bit in the RX descriptor. This
 * method cannot be used on the NFP-3200 as it causes a race
 * condition: The RX ring write pointer on the NFP-3200 is updated
 * after packets (and descriptors) have been DMAed.  If the DD bit is
 * used and subsequently the read pointer is updated this may lead to
 * the RX queue to underflow (if the firmware has not yet update the
 * write pointer).  Therefore we use slightly ugly conditional code
 * below to handle the differences.  We may, in the future update the
 * NFP-3200 firmware to behave the same as the firmware on the
 * NFP-6000.
 *
 * Return: Number of packets received.
 */
static int nfp_net_rx(struct nfp_net_rx_ring *rx_ring, int budget)
{
        struct nfp_net_r_vector *r_vec = rx_ring->r_vec;
        struct nfp_net *nn = r_vec->nfp_net;
        unsigned int data_len, meta_len;
        int avail = 0, pkts_polled = 0;
        struct sk_buff *skb, *new_skb;
        struct nfp_net_rx_desc *rxd;
        dma_addr_t new_dma_addr;
        u32 qcp_wr_p;
        int idx;

        if (nn->is_nfp3200) {
                /* Work out how many packets arrived */
                qcp_wr_p = nfp_qcp_wr_ptr_read(rx_ring->qcp_rx);
                idx = rx_ring->rd_p % rx_ring->cnt;

                if (qcp_wr_p == idx)
                        /* No new packets */
                        return 0;

                if (qcp_wr_p > idx)
                        avail = qcp_wr_p - idx;
                else
                        avail = qcp_wr_p + rx_ring->cnt - idx;
        } else {
                avail = budget + 1;
        }

        while (avail > 0 && pkts_polled < budget) {
                idx = rx_ring->rd_p % rx_ring->cnt;

                rxd = &rx_ring->rxds[idx];
                if (!(rxd->rxd.meta_len_dd & PCIE_DESC_RX_DD)) {
                        if (nn->is_nfp3200)
                                nn_dbg(nn, "RX descriptor not valid (DD)%d:%u rxd[0]=%#x rxd[1]=%#x\n",
                                       rx_ring->idx, idx,
                                       rxd->vals[0], rxd->vals[1]);
                        break;
                }
                /* Memory barrier to ensure that we won't do other reads
                 * before the DD bit.
                 */
                dma_rmb();

                rx_ring->rd_p++;
                pkts_polled++;
                avail--;

                skb = rx_ring->rxbufs[idx].skb;

                new_skb = nfp_net_rx_alloc_one(rx_ring, &new_dma_addr,
                                               nn->fl_bufsz);
                if (!new_skb) {
                        nfp_net_rx_give_one(rx_ring, rx_ring->rxbufs[idx].skb,
                                            rx_ring->rxbufs[idx].dma_addr);
                        u64_stats_update_begin(&r_vec->rx_sync);
                        r_vec->rx_drops++;
                        u64_stats_update_end(&r_vec->rx_sync);
                        continue;
                }

                dma_unmap_single(&nn->pdev->dev,
                                 rx_ring->rxbufs[idx].dma_addr,
                                 nn->fl_bufsz, DMA_FROM_DEVICE);

                nfp_net_rx_give_one(rx_ring, new_skb, new_dma_addr);

                /*         < meta_len >
                 *  <-- [rx_offset] -->
                 *  ---------------------------------------------------------
                 * | [XX] |  metadata  |             packet           | XXXX |
                 *  ---------------------------------------------------------
                 *         <---------------- data_len --------------->
                 *
                 * The rx_offset is fixed for all packets, the meta_len can vary
                 * on a packet by packet basis. If rx_offset is set to zero
                 * (_RX_OFFSET_DYNAMIC) metadata starts at the beginning of the
                 * buffer and is immediately followed by the packet (no [XX]).
                 */
                meta_len = rxd->rxd.meta_len_dd & PCIE_DESC_RX_META_LEN_MASK;
                data_len = le16_to_cpu(rxd->rxd.data_len);

                if (nn->rx_offset == NFP_NET_CFG_RX_OFFSET_DYNAMIC)
                        skb_reserve(skb, meta_len);
                else
                        skb_reserve(skb, nn->rx_offset);
                skb_put(skb, data_len - meta_len);

                nfp_net_set_hash(nn->netdev, skb, rxd);

                /* Pad small frames to minimum */
                if (skb_put_padto(skb, 60))
                        break;

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

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

                nfp_net_rx_csum(nn, r_vec, rxd, skb);

                if (rxd->rxd.flags & PCIE_DESC_RX_VLAN)
                        __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                               le16_to_cpu(rxd->rxd.vlan));

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

        if (nn->is_nfp3200)
                nfp_qcp_rd_ptr_add(rx_ring->qcp_rx, pkts_polled);

        return pkts_polled;
}

/**
 * nfp_net_poll() - napi poll function
 * @napi:    NAPI structure
 * @budget:  NAPI budget
 *
 * Return: number of packets polled.
 */
static int nfp_net_poll(struct napi_struct *napi, int budget)
{
        struct nfp_net_r_vector *r_vec =
                container_of(napi, struct nfp_net_r_vector, napi);
        struct nfp_net_rx_ring *rx_ring = r_vec->rx_ring;
        struct nfp_net_tx_ring *tx_ring = r_vec->tx_ring;
        struct nfp_net *nn = r_vec->nfp_net;
        struct netdev_queue *txq;
        unsigned int pkts_polled;

        tx_ring = &nn->tx_rings[rx_ring->idx];
        txq = netdev_get_tx_queue(nn->netdev, tx_ring->idx);
        nfp_net_tx_complete(tx_ring);

        pkts_polled = nfp_net_rx(rx_ring, budget);

        if (pkts_polled < budget) {
                napi_complete_done(napi, pkts_polled);
                nfp_net_irq_unmask(nn, r_vec->irq_idx);
        }

        return pkts_polled;
}

/* Setup and Configuration
 */

/**
 * nfp_net_tx_ring_free() - Free resources allocated to a TX ring
 * @tx_ring:   TX ring to free
 */
static void nfp_net_tx_ring_free(struct nfp_net_tx_ring *tx_ring)
{
        struct nfp_net_r_vector *r_vec = tx_ring->r_vec;
        struct nfp_net *nn = r_vec->nfp_net;
        struct pci_dev *pdev = nn->pdev;

        kfree(tx_ring->txbufs);

        if (tx_ring->txds)
                dma_free_coherent(&pdev->dev, tx_ring->size,
                                  tx_ring->txds, tx_ring->dma);

        tx_ring->cnt = 0;
        tx_ring->txbufs = NULL;
        tx_ring->txds = NULL;
        tx_ring->dma = 0;
        tx_ring->size = 0;
}

/**
 * nfp_net_tx_ring_alloc() - Allocate resource for a TX ring
 * @tx_ring:   TX Ring structure to allocate
 * @cnt:       Ring buffer count
 *
 * Return: 0 on success, negative errno otherwise.
 */
static int nfp_net_tx_ring_alloc(struct nfp_net_tx_ring *tx_ring, u32 cnt)
{
        struct nfp_net_r_vector *r_vec = tx_ring->r_vec;
        struct nfp_net *nn = r_vec->nfp_net;
        struct pci_dev *pdev = nn->pdev;
        int sz;

        tx_ring->cnt = cnt;

        tx_ring->size = sizeof(*tx_ring->txds) * tx_ring->cnt;
        tx_ring->txds = dma_zalloc_coherent(&pdev->dev, tx_ring->size,
                                            &tx_ring->dma, GFP_KERNEL);
        if (!tx_ring->txds)
                goto err_alloc;

        sz = sizeof(*tx_ring->txbufs) * tx_ring->cnt;
        tx_ring->txbufs = kzalloc(sz, GFP_KERNEL);
        if (!tx_ring->txbufs)
                goto err_alloc;

        netif_set_xps_queue(nn->netdev, &r_vec->affinity_mask, tx_ring->idx);

        nn_dbg(nn, "TxQ%02d: QCidx=%02d cnt=%d dma=%#llx host=%p\n",
               tx_ring->idx, tx_ring->qcidx,
               tx_ring->cnt, (unsigned long long)tx_ring->dma, tx_ring->txds);

        return 0;

err_alloc:
        nfp_net_tx_ring_free(tx_ring);
        return -ENOMEM;
}

static struct nfp_net_tx_ring *
nfp_net_shadow_tx_rings_prepare(struct nfp_net *nn, u32 buf_cnt)
{
        struct nfp_net_tx_ring *rings;
        unsigned int r;

        rings = kcalloc(nn->num_tx_rings, sizeof(*rings), GFP_KERNEL);
        if (!rings)
                return NULL;

        for (r = 0; r < nn->num_tx_rings; r++) {
                nfp_net_tx_ring_init(&rings[r], nn->tx_rings[r].r_vec, r);

                if (nfp_net_tx_ring_alloc(&rings[r], buf_cnt))
                        goto err_free_prev;
        }

        return rings;

err_free_prev:
        while (r--)
                nfp_net_tx_ring_free(&rings[r]);
        kfree(rings);
        return NULL;
}

static struct nfp_net_tx_ring *
nfp_net_shadow_tx_rings_swap(struct nfp_net *nn, struct nfp_net_tx_ring *rings)
{
        struct nfp_net_tx_ring *old = nn->tx_rings;
        unsigned int r;

        for (r = 0; r < nn->num_tx_rings; r++)
                old[r].r_vec->tx_ring = &rings[r];

        nn->tx_rings = rings;
        return old;
}

static void
nfp_net_shadow_tx_rings_free(struct nfp_net *nn, struct nfp_net_tx_ring *rings)
{
        unsigned int r;

        if (!rings)
                return;

        for (r = 0; r < nn->num_tx_rings; r++)
                nfp_net_tx_ring_free(&rings[r]);

        kfree(rings);
}

/**
 * nfp_net_rx_ring_free() - Free resources allocated to a RX ring
 * @rx_ring:  RX ring to free
 */
static void nfp_net_rx_ring_free(struct nfp_net_rx_ring *rx_ring)
{
        struct nfp_net_r_vector *r_vec = rx_ring->r_vec;
        struct nfp_net *nn = r_vec->nfp_net;
        struct pci_dev *pdev = nn->pdev;

        kfree(rx_ring->rxbufs);

        if (rx_ring->rxds)
                dma_free_coherent(&pdev->dev, rx_ring->size,
                                  rx_ring->rxds, rx_ring->dma);

        rx_ring->cnt = 0;
        rx_ring->rxbufs = NULL;
        rx_ring->rxds = NULL;
        rx_ring->dma = 0;
        rx_ring->size = 0;
}

/**
 * nfp_net_rx_ring_alloc() - Allocate resource for a RX ring
 * @rx_ring:  RX ring to allocate
 * @fl_bufsz: Size of buffers to allocate
 * @cnt:      Ring buffer count
 *
 * Return: 0 on success, negative errno otherwise.
 */
static int
nfp_net_rx_ring_alloc(struct nfp_net_rx_ring *rx_ring, unsigned int fl_bufsz,
                      u32 cnt)
{
        struct nfp_net_r_vector *r_vec = rx_ring->r_vec;
        struct nfp_net *nn = r_vec->nfp_net;
        struct pci_dev *pdev = nn->pdev;
        int sz;

        rx_ring->cnt = cnt;
        rx_ring->bufsz = fl_bufsz;

        rx_ring->size = sizeof(*rx_ring->rxds) * rx_ring->cnt;
        rx_ring->rxds = dma_zalloc_coherent(&pdev->dev, rx_ring->size,
                                            &rx_ring->dma, GFP_KERNEL);
        if (!rx_ring->rxds)
                goto err_alloc;

        sz = sizeof(*rx_ring->rxbufs) * rx_ring->cnt;
        rx_ring->rxbufs = kzalloc(sz, GFP_KERNEL);
        if (!rx_ring->rxbufs)
                goto err_alloc;

        nn_dbg(nn, "RxQ%02d: FlQCidx=%02d RxQCidx=%02d cnt=%d dma=%#llx host=%p\n",
               rx_ring->idx, rx_ring->fl_qcidx, rx_ring->rx_qcidx,
               rx_ring->cnt, (unsigned long long)rx_ring->dma, rx_ring->rxds);

        return 0;

err_alloc:
        nfp_net_rx_ring_free(rx_ring);
        return -ENOMEM;
}

static struct nfp_net_rx_ring *
nfp_net_shadow_rx_rings_prepare(struct nfp_net *nn, unsigned int fl_bufsz,
                                u32 buf_cnt)
{
        struct nfp_net_rx_ring *rings;
        unsigned int r;

        rings = kcalloc(nn->num_rx_rings, sizeof(*rings), GFP_KERNEL);
        if (!rings)
                return NULL;

        for (r = 0; r < nn->num_rx_rings; r++) {
                nfp_net_rx_ring_init(&rings[r], nn->rx_rings[r].r_vec, r);

                if (nfp_net_rx_ring_alloc(&rings[r], fl_bufsz, buf_cnt))
                        goto err_free_prev;

                if (nfp_net_rx_ring_bufs_alloc(nn, &rings[r]))
                        goto err_free_ring;
        }

        return rings;

err_free_prev:
        while (r--) {
                nfp_net_rx_ring_bufs_free(nn, &rings[r]);
err_free_ring:
                nfp_net_rx_ring_free(&rings[r]);
        }
        kfree(rings);
        return NULL;
}

static struct nfp_net_rx_ring *
nfp_net_shadow_rx_rings_swap(struct nfp_net *nn, struct nfp_net_rx_ring *rings)
{
        struct nfp_net_rx_ring *old = nn->rx_rings;
        unsigned int r;

        for (r = 0; r < nn->num_rx_rings; r++)
                old[r].r_vec->rx_ring = &rings[r];

        nn->rx_rings = rings;
        return old;
}

static void
nfp_net_shadow_rx_rings_free(struct nfp_net *nn, struct nfp_net_rx_ring *rings)
{
        unsigned int r;

        if (!rings)
                return;

        for (r = 0; r < nn->num_r_vecs; r++) {
                nfp_net_rx_ring_bufs_free(nn, &rings[r]);
                nfp_net_rx_ring_free(&rings[r]);
        }

        kfree(rings);
}

static int
nfp_net_prepare_vector(struct nfp_net *nn, struct nfp_net_r_vector *r_vec,
                       int idx)
{
        struct msix_entry *entry = &nn->irq_entries[r_vec->irq_idx];
        int err;

        r_vec->tx_ring = &nn->tx_rings[idx];
        nfp_net_tx_ring_init(r_vec->tx_ring, r_vec, idx);

        r_vec->rx_ring = &nn->rx_rings[idx];
        nfp_net_rx_ring_init(r_vec->rx_ring, r_vec, idx);

        snprintf(r_vec->name, sizeof(r_vec->name),
                 "%s-rxtx-%d", nn->netdev->name, idx);
        err = request_irq(entry->vector, r_vec->handler, 0, r_vec->name, r_vec);
        if (err) {
                nn_err(nn, "Error requesting IRQ %d\n", entry->vector);
                return err;
        }
        disable_irq(entry->vector);

        /* Setup NAPI */
        netif_napi_add(nn->netdev, &r_vec->napi,
                       nfp_net_poll, NAPI_POLL_WEIGHT);

        irq_set_affinity_hint(entry->vector, &r_vec->affinity_mask);

        nn_dbg(nn, "RV%02d: irq=%03d/%03d\n", idx, entry->vector, entry->entry);

        return 0;
}

static void
nfp_net_cleanup_vector(struct nfp_net *nn, struct nfp_net_r_vector *r_vec)
{
        struct msix_entry *entry = &nn->irq_entries[r_vec->irq_idx];

        irq_set_affinity_hint(entry->vector, NULL);
        netif_napi_del(&r_vec->napi);
        free_irq(entry->vector, r_vec);
}

/**
 * nfp_net_rss_write_itbl() - Write RSS indirection table to device
 * @nn:      NFP Net device to reconfigure
 */
void nfp_net_rss_write_itbl(struct nfp_net *nn)
{
        int i;

        for (i = 0; i < NFP_NET_CFG_RSS_ITBL_SZ; i += 4)
                nn_writel(nn, NFP_NET_CFG_RSS_ITBL + i,
                          get_unaligned_le32(nn->rss_itbl + i));
}

/**
 * nfp_net_rss_write_key() - Write RSS hash key to device
 * @nn:      NFP Net device to reconfigure
 */
void nfp_net_rss_write_key(struct nfp_net *nn)
{
        int i;

        for (i = 0; i < NFP_NET_CFG_RSS_KEY_SZ; i += 4)
                nn_writel(nn, NFP_NET_CFG_RSS_KEY + i,
                          get_unaligned_le32(nn->rss_key + i));
}

/**
 * nfp_net_coalesce_write_cfg() - Write irq coalescence configuration to HW
 * @nn:      NFP Net device to reconfigure
 */
void nfp_net_coalesce_write_cfg(struct nfp_net *nn)
{
        u8 i;
        u32 factor;
        u32 value;

        /* Compute factor used to convert coalesce '_usecs' parameters to
         * ME timestamp ticks.  There are 16 ME clock cycles for each timestamp
         * count.
         */
        factor = nn->me_freq_mhz / 16;

        /* copy RX interrupt coalesce parameters */
        value = (nn->rx_coalesce_max_frames << 16) |
                (factor * nn->rx_coalesce_usecs);
        for (i = 0; i < nn->num_r_vecs; i++)
                nn_writel(nn, NFP_NET_CFG_RXR_IRQ_MOD(i), value);

        /* copy TX interrupt coalesce parameters */
        value = (nn->tx_coalesce_max_frames << 16) |
                (factor * nn->tx_coalesce_usecs);
        for (i = 0; i < nn->num_r_vecs; i++)
                nn_writel(nn, NFP_NET_CFG_TXR_IRQ_MOD(i), value);
}

/**
 * nfp_net_write_mac_addr() - Write mac address to device registers
 * @nn:      NFP Net device to reconfigure
 * @mac:     Six-byte MAC address to be written
 *
 * We do a bit of byte swapping dance because firmware is LE.
 */
static void nfp_net_write_mac_addr(struct nfp_net *nn, const u8 *mac)
{
        nn_writel(nn, NFP_NET_CFG_MACADDR + 0,
                  get_unaligned_be32(nn->netdev->dev_addr));
        /* We can't do writew for NFP-3200 compatibility */
        nn_writel(nn, NFP_NET_CFG_MACADDR + 4,
                  get_unaligned_be16(nn->netdev->dev_addr + 4) << 16);
}

static void nfp_net_vec_clear_ring_data(struct nfp_net *nn, unsigned int idx)
{
        nn_writeq(nn, NFP_NET_CFG_RXR_ADDR(idx), 0);
        nn_writeb(nn, NFP_NET_CFG_RXR_SZ(idx), 0);
        nn_writeb(nn, NFP_NET_CFG_RXR_VEC(idx), 0);

        nn_writeq(nn, NFP_NET_CFG_TXR_ADDR(idx), 0);
        nn_writeb(nn, NFP_NET_CFG_TXR_SZ(idx), 0);
        nn_writeb(nn, NFP_NET_CFG_TXR_VEC(idx), 0);
}

/**
 * nfp_net_clear_config_and_disable() - Clear control BAR and disable NFP
 * @nn:      NFP Net device to reconfigure
 */
static void nfp_net_clear_config_and_disable(struct nfp_net *nn)
{
        u32 new_ctrl, update;
        unsigned int r;
        int err;

        new_ctrl = nn->ctrl;
        new_ctrl &= ~NFP_NET_CFG_CTRL_ENABLE;
        update = NFP_NET_CFG_UPDATE_GEN;
        update |= NFP_NET_CFG_UPDATE_MSIX;
        update |= NFP_NET_CFG_UPDATE_RING;

        if (nn->cap & NFP_NET_CFG_CTRL_RINGCFG)
                new_ctrl &= ~NFP_NET_CFG_CTRL_RINGCFG;

        nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, 0);
        nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, 0);

        nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
        err = nfp_net_reconfig(nn, update);
        if (err)
                nn_err(nn, "Could not disable device: %d\n", err);

        for (r = 0; r < nn->num_r_vecs; r++) {
                nfp_net_rx_ring_reset(nn->r_vecs[r].rx_ring);
                nfp_net_tx_ring_reset(nn, nn->r_vecs[r].tx_ring);
                nfp_net_vec_clear_ring_data(nn, r);
        }

        nn->ctrl = new_ctrl;
}

static void
nfp_net_vec_write_ring_data(struct nfp_net *nn, struct nfp_net_r_vector *r_vec,
                            unsigned int idx)
{
        /* Write the DMA address, size and MSI-X info to the device */
        nn_writeq(nn, NFP_NET_CFG_RXR_ADDR(idx), r_vec->rx_ring->dma);
        nn_writeb(nn, NFP_NET_CFG_RXR_SZ(idx), ilog2(r_vec->rx_ring->cnt));
        nn_writeb(nn, NFP_NET_CFG_RXR_VEC(idx), r_vec->irq_idx);

        nn_writeq(nn, NFP_NET_CFG_TXR_ADDR(idx), r_vec->tx_ring->dma);
        nn_writeb(nn, NFP_NET_CFG_TXR_SZ(idx), ilog2(r_vec->tx_ring->cnt));
        nn_writeb(nn, NFP_NET_CFG_TXR_VEC(idx), r_vec->irq_idx);
}

static int __nfp_net_set_config_and_enable(struct nfp_net *nn)
{
        u32 new_ctrl, update = 0;
        unsigned int r;
        int err;

        new_ctrl = nn->ctrl;

        if (nn->cap & NFP_NET_CFG_CTRL_RSS) {
                nfp_net_rss_write_key(nn);
                nfp_net_rss_write_itbl(nn);
                nn_writel(nn, NFP_NET_CFG_RSS_CTRL, nn->rss_cfg);
                update |= NFP_NET_CFG_UPDATE_RSS;
        }

        if (nn->cap & NFP_NET_CFG_CTRL_IRQMOD) {
                nfp_net_coalesce_write_cfg(nn);

                new_ctrl |= NFP_NET_CFG_CTRL_IRQMOD;
                update |= NFP_NET_CFG_UPDATE_IRQMOD;
        }

        for (r = 0; r < nn->num_r_vecs; r++)
                nfp_net_vec_write_ring_data(nn, &nn->r_vecs[r], r);

        nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, nn->num_tx_rings == 64 ?
                  0xffffffffffffffffULL : ((u64)1 << nn->num_tx_rings) - 1);

        nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, nn->num_rx_rings == 64 ?
                  0xffffffffffffffffULL : ((u64)1 << nn->num_rx_rings) - 1);

        nfp_net_write_mac_addr(nn, nn->netdev->dev_addr);

        nn_writel(nn, NFP_NET_CFG_MTU, nn->netdev->mtu);
        nn_writel(nn, NFP_NET_CFG_FLBUFSZ, nn->fl_bufsz);

        /* Enable device */
        new_ctrl |= NFP_NET_CFG_CTRL_ENABLE;
        update |= NFP_NET_CFG_UPDATE_GEN;
        update |= NFP_NET_CFG_UPDATE_MSIX;
        update |= NFP_NET_CFG_UPDATE_RING;
        if (nn->cap & NFP_NET_CFG_CTRL_RINGCFG)
                new_ctrl |= NFP_NET_CFG_CTRL_RINGCFG;

        nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
        err = nfp_net_reconfig(nn, update);

        nn->ctrl = new_ctrl;

        for (r = 0; r < nn->num_r_vecs; r++)
                nfp_net_rx_ring_fill_freelist(nn->r_vecs[r].rx_ring);

        /* Since reconfiguration requests while NFP is down are ignored we
         * have to wipe the entire VXLAN configuration and reinitialize it.
         */
        if (nn->ctrl & NFP_NET_CFG_CTRL_VXLAN) {
                memset(&nn->vxlan_ports, 0, sizeof(nn->vxlan_ports));
                memset(&nn->vxlan_usecnt, 0, sizeof(nn->vxlan_usecnt));
                vxlan_get_rx_port(nn->netdev);
        }

        return err;
}

/**
 * nfp_net_set_config_and_enable() - Write control BAR and enable NFP
 * @nn:      NFP Net device to reconfigure
 */
static int nfp_net_set_config_and_enable(struct nfp_net *nn)
{
        int err;

        err = __nfp_net_set_config_and_enable(nn);
        if (err)
                nfp_net_clear_config_and_disable(nn);

        return err;
}

/**
 * nfp_net_open_stack() - Start the device from stack's perspective
 * @nn:      NFP Net device to reconfigure
 */
static void nfp_net_open_stack(struct nfp_net *nn)
{
        unsigned int r;

        for (r = 0; r < nn->num_r_vecs; r++) {
                napi_enable(&nn->r_vecs[r].napi);
                enable_irq(nn->irq_entries[nn->r_vecs[r].irq_idx].vector);
        }

        netif_tx_wake_all_queues(nn->netdev);

        enable_irq(nn->irq_entries[NFP_NET_IRQ_LSC_IDX].vector);
        nfp_net_read_link_status(nn);
}

static int nfp_net_netdev_open(struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);
        int err, r;

        if (nn->ctrl & NFP_NET_CFG_CTRL_ENABLE) {
                nn_err(nn, "Dev is already enabled: 0x%08x\n", nn->ctrl);
                return -EBUSY;
        }

        /* Step 1: Allocate resources for rings and the like
         * - Request interrupts
         * - Allocate RX and TX ring resources
         * - Setup initial RSS table
         */
        err = nfp_net_aux_irq_request(nn, NFP_NET_CFG_EXN, "%s-exn",
                                      nn->exn_name, sizeof(nn->exn_name),
                                      NFP_NET_IRQ_EXN_IDX, nn->exn_handler);
        if (err)
                return err;
        err = nfp_net_aux_irq_request(nn, NFP_NET_CFG_LSC, "%s-lsc",
                                      nn->lsc_name, sizeof(nn->lsc_name),
                                      NFP_NET_IRQ_LSC_IDX, nn->lsc_handler);
        if (err)
                goto err_free_exn;
        disable_irq(nn->irq_entries[NFP_NET_IRQ_LSC_IDX].vector);

        nn->rx_rings = kcalloc(nn->num_rx_rings, sizeof(*nn->rx_rings),
                               GFP_KERNEL);
        if (!nn->rx_rings)
                goto err_free_lsc;
        nn->tx_rings = kcalloc(nn->num_tx_rings, sizeof(*nn->tx_rings),
                               GFP_KERNEL);
        if (!nn->tx_rings)
                goto err_free_rx_rings;

        for (r = 0; r < nn->num_r_vecs; r++) {
                err = nfp_net_prepare_vector(nn, &nn->r_vecs[r], r);
                if (err)
                        goto err_free_prev_vecs;

                err = nfp_net_tx_ring_alloc(nn->r_vecs[r].tx_ring, nn->txd_cnt);
                if (err)
                        goto err_cleanup_vec_p;

                err = nfp_net_rx_ring_alloc(nn->r_vecs[r].rx_ring,
                                            nn->fl_bufsz, nn->rxd_cnt);
                if (err)
                        goto err_free_tx_ring_p;

                err = nfp_net_rx_ring_bufs_alloc(nn, nn->r_vecs[r].rx_ring);
                if (err)
                        goto err_flush_rx_ring_p;
        }

        err = netif_set_real_num_tx_queues(netdev, nn->num_tx_rings);
        if (err)
                goto err_free_rings;

        err = netif_set_real_num_rx_queues(netdev, nn->num_rx_rings);
        if (err)
                goto err_free_rings;

        /* Step 2: Configure the NFP
         * - Enable rings from 0 to tx_rings/rx_rings - 1.
         * - Write MAC address (in case it changed)
         * - Set the MTU
         * - Set the Freelist buffer size
         * - Enable the FW
         */
        err = nfp_net_set_config_and_enable(nn);
        if (err)
                goto err_free_rings;

        /* Step 3: Enable for kernel
         * - put some freelist descriptors on each RX ring
         * - enable NAPI on each ring
         * - enable all TX queues
         * - set link state
         */
        nfp_net_open_stack(nn);

        return 0;

err_free_rings:
        r = nn->num_r_vecs;
err_free_prev_vecs:
        while (r--) {
                nfp_net_rx_ring_bufs_free(nn, nn->r_vecs[r].rx_ring);
err_flush_rx_ring_p:
                nfp_net_rx_ring_free(nn->r_vecs[r].rx_ring);
err_free_tx_ring_p:
                nfp_net_tx_ring_free(nn->r_vecs[r].tx_ring);
err_cleanup_vec_p:
                nfp_net_cleanup_vector(nn, &nn->r_vecs[r]);
        }
        kfree(nn->tx_rings);
err_free_rx_rings:
        kfree(nn->rx_rings);
err_free_lsc:
        nfp_net_aux_irq_free(nn, NFP_NET_CFG_LSC, NFP_NET_IRQ_LSC_IDX);
err_free_exn:
        nfp_net_aux_irq_free(nn, NFP_NET_CFG_EXN, NFP_NET_IRQ_EXN_IDX);
        return err;
}

/**
 * nfp_net_close_stack() - Quiescent the stack (part of close)
 * @nn:      NFP Net device to reconfigure
 */
static void nfp_net_close_stack(struct nfp_net *nn)
{
        unsigned int r;

        disable_irq(nn->irq_entries[NFP_NET_IRQ_LSC_IDX].vector);
        netif_carrier_off(nn->netdev);
        nn->link_up = false;

        for (r = 0; r < nn->num_r_vecs; r++) {
                disable_irq(nn->irq_entries[nn->r_vecs[r].irq_idx].vector);
                napi_disable(&nn->r_vecs[r].napi);
        }

        netif_tx_disable(nn->netdev);
}

/**
 * nfp_net_close_free_all() - Free all runtime resources
 * @nn:      NFP Net device to reconfigure
 */
static void nfp_net_close_free_all(struct nfp_net *nn)
{
        unsigned int r;

        for (r = 0; r < nn->num_r_vecs; r++) {
                nfp_net_rx_ring_bufs_free(nn, nn->r_vecs[r].rx_ring);
                nfp_net_rx_ring_free(nn->r_vecs[r].rx_ring);
                nfp_net_tx_ring_free(nn->r_vecs[r].tx_ring);
                nfp_net_cleanup_vector(nn, &nn->r_vecs[r]);
        }

        kfree(nn->rx_rings);
        kfree(nn->tx_rings);

        nfp_net_aux_irq_free(nn, NFP_NET_CFG_LSC, NFP_NET_IRQ_LSC_IDX);
        nfp_net_aux_irq_free(nn, NFP_NET_CFG_EXN, NFP_NET_IRQ_EXN_IDX);
}

/**
 * nfp_net_netdev_close() - Called when the device is downed
 * @netdev:      netdev structure
 */
static int nfp_net_netdev_close(struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);

        if (!(nn->ctrl & NFP_NET_CFG_CTRL_ENABLE)) {
                nn_err(nn, "Dev is not up: 0x%08x\n", nn->ctrl);
                return 0;
        }

        /* Step 1: Disable RX and TX rings from the Linux kernel perspective
         */
        nfp_net_close_stack(nn);

        /* Step 2: Tell NFP
         */
        nfp_net_clear_config_and_disable(nn);

        /* Step 3: Free resources
         */
        nfp_net_close_free_all(nn);

        nn_dbg(nn, "%s down", netdev->name);
        return 0;
}

static void nfp_net_set_rx_mode(struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);
        u32 new_ctrl;

        new_ctrl = nn->ctrl;

        if (netdev->flags & IFF_PROMISC) {
                if (nn->cap & NFP_NET_CFG_CTRL_PROMISC)
                        new_ctrl |= NFP_NET_CFG_CTRL_PROMISC;
                else
                        nn_warn(nn, "FW does not support promiscuous mode\n");
        } else {
                new_ctrl &= ~NFP_NET_CFG_CTRL_PROMISC;
        }

        if (new_ctrl == nn->ctrl)
                return;

        nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
        nfp_net_reconfig_post(nn, NFP_NET_CFG_UPDATE_GEN);

        nn->ctrl = new_ctrl;
}

static int nfp_net_change_mtu(struct net_device *netdev, int new_mtu)
{
        unsigned int old_mtu, old_fl_bufsz, new_fl_bufsz;
        struct nfp_net *nn = netdev_priv(netdev);
        struct nfp_net_rx_ring *tmp_rings;
        int err;

        if (new_mtu < 68 || new_mtu > nn->max_mtu) {
                nn_err(nn, "New MTU (%d) is not valid\n", new_mtu);
                return -EINVAL;
        }

        old_mtu = netdev->mtu;
        old_fl_bufsz = nn->fl_bufsz;
        new_fl_bufsz = NFP_NET_MAX_PREPEND + ETH_HLEN + VLAN_HLEN * 2 + new_mtu;

        if (!netif_running(netdev)) {
                netdev->mtu = new_mtu;
                nn->fl_bufsz = new_fl_bufsz;
                return 0;
        }

        /* Prepare new rings */
        tmp_rings = nfp_net_shadow_rx_rings_prepare(nn, new_fl_bufsz,
                                                    nn->rxd_cnt);
        if (!tmp_rings)
                return -ENOMEM;

        /* Stop device, swap in new rings, try to start the firmware */
        nfp_net_close_stack(nn);
        nfp_net_clear_config_and_disable(nn);

        tmp_rings = nfp_net_shadow_rx_rings_swap(nn, tmp_rings);

        netdev->mtu = new_mtu;
        nn->fl_bufsz = new_fl_bufsz;

        err = nfp_net_set_config_and_enable(nn);
        if (err) {
                const int err_new = err;

                /* Try with old configuration and old rings */
                tmp_rings = nfp_net_shadow_rx_rings_swap(nn, tmp_rings);

                netdev->mtu = old_mtu;
                nn->fl_bufsz = old_fl_bufsz;

                err = __nfp_net_set_config_and_enable(nn);
                if (err)
                        nn_err(nn, "Can't restore MTU - FW communication failed (%d,%d)\n",
                               err_new, err);
        }

        nfp_net_shadow_rx_rings_free(nn, tmp_rings);

        nfp_net_open_stack(nn);

        return err;
}

int nfp_net_set_ring_size(struct nfp_net *nn, u32 rxd_cnt, u32 txd_cnt)
{
        struct nfp_net_tx_ring *tx_rings = NULL;
        struct nfp_net_rx_ring *rx_rings = NULL;
        u32 old_rxd_cnt, old_txd_cnt;
        int err;

        if (!netif_running(nn->netdev)) {
                nn->rxd_cnt = rxd_cnt;
                nn->txd_cnt = txd_cnt;
                return 0;
        }

        old_rxd_cnt = nn->rxd_cnt;
        old_txd_cnt = nn->txd_cnt;

        /* Prepare new rings */
        if (nn->rxd_cnt != rxd_cnt) {
                rx_rings = nfp_net_shadow_rx_rings_prepare(nn, nn->fl_bufsz,
                                                           rxd_cnt);
                if (!rx_rings)
                        return -ENOMEM;
        }
        if (nn->txd_cnt != txd_cnt) {
                tx_rings = nfp_net_shadow_tx_rings_prepare(nn, txd_cnt);
                if (!tx_rings) {
                        nfp_net_shadow_rx_rings_free(nn, rx_rings);
                        return -ENOMEM;
                }
        }

        /* Stop device, swap in new rings, try to start the firmware */
        nfp_net_close_stack(nn);
        nfp_net_clear_config_and_disable(nn);

        if (rx_rings)
                rx_rings = nfp_net_shadow_rx_rings_swap(nn, rx_rings);
        if (tx_rings)
                tx_rings = nfp_net_shadow_tx_rings_swap(nn, tx_rings);

        nn->rxd_cnt = rxd_cnt;
        nn->txd_cnt = txd_cnt;

        err = nfp_net_set_config_and_enable(nn);
        if (err) {
                const int err_new = err;

                /* Try with old configuration and old rings */
                if (rx_rings)
                        rx_rings = nfp_net_shadow_rx_rings_swap(nn, rx_rings);
                if (tx_rings)
                        tx_rings = nfp_net_shadow_tx_rings_swap(nn, tx_rings);

                nn->rxd_cnt = old_rxd_cnt;
                nn->txd_cnt = old_txd_cnt;

                err = __nfp_net_set_config_and_enable(nn);
                if (err)
                        nn_err(nn, "Can't restore ring config - FW communication failed (%d,%d)\n",
                               err_new, err);
        }

        nfp_net_shadow_rx_rings_free(nn, rx_rings);
        nfp_net_shadow_tx_rings_free(nn, tx_rings);

        nfp_net_open_stack(nn);

        return err;
}

static struct rtnl_link_stats64 *nfp_net_stat64(struct net_device *netdev,
                                                struct rtnl_link_stats64 *stats)
{
        struct nfp_net *nn = netdev_priv(netdev);
        int r;

        for (r = 0; r < nn->num_r_vecs; r++) {
                struct nfp_net_r_vector *r_vec = &nn->r_vecs[r];
                u64 data[3];
                unsigned int start;

                do {
                        start = u64_stats_fetch_begin(&r_vec->rx_sync);
                        data[0] = r_vec->rx_pkts;
                        data[1] = r_vec->rx_bytes;
                        data[2] = r_vec->rx_drops;
                } while (u64_stats_fetch_retry(&r_vec->rx_sync, start));
                stats->rx_packets += data[0];
                stats->rx_bytes += data[1];
                stats->rx_dropped += data[2];

                do {
                        start = u64_stats_fetch_begin(&r_vec->tx_sync);
                        data[0] = r_vec->tx_pkts;
                        data[1] = r_vec->tx_bytes;
                        data[2] = r_vec->tx_errors;
                } while (u64_stats_fetch_retry(&r_vec->tx_sync, start));
                stats->tx_packets += data[0];
                stats->tx_bytes += data[1];
                stats->tx_errors += data[2];
        }

        return stats;
}

static int nfp_net_set_features(struct net_device *netdev,
                                netdev_features_t features)
{
        netdev_features_t changed = netdev->features ^ features;
        struct nfp_net *nn = netdev_priv(netdev);
        u32 new_ctrl;
        int err;

        /* Assume this is not called with features we have not advertised */

        new_ctrl = nn->ctrl;

        if (changed & NETIF_F_RXCSUM) {
                if (features & NETIF_F_RXCSUM)
                        new_ctrl |= NFP_NET_CFG_CTRL_RXCSUM;
                else
                        new_ctrl &= ~NFP_NET_CFG_CTRL_RXCSUM;
        }

        if (changed & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)) {
                if (features & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM))
                        new_ctrl |= NFP_NET_CFG_CTRL_TXCSUM;
                else
                        new_ctrl &= ~NFP_NET_CFG_CTRL_TXCSUM;
        }

        if (changed & (NETIF_F_TSO | NETIF_F_TSO6)) {
                if (features & (NETIF_F_TSO | NETIF_F_TSO6))
                        new_ctrl |= NFP_NET_CFG_CTRL_LSO;
                else
                        new_ctrl &= ~NFP_NET_CFG_CTRL_LSO;
        }

        if (changed & NETIF_F_HW_VLAN_CTAG_RX) {
                if (features & NETIF_F_HW_VLAN_CTAG_RX)
                        new_ctrl |= NFP_NET_CFG_CTRL_RXVLAN;
                else
                        new_ctrl &= ~NFP_NET_CFG_CTRL_RXVLAN;
        }

        if (changed & NETIF_F_HW_VLAN_CTAG_TX) {
                if (features & NETIF_F_HW_VLAN_CTAG_TX)
                        new_ctrl |= NFP_NET_CFG_CTRL_TXVLAN;
                else
                        new_ctrl &= ~NFP_NET_CFG_CTRL_TXVLAN;
        }

        if (changed & NETIF_F_SG) {
                if (features & NETIF_F_SG)
                        new_ctrl |= NFP_NET_CFG_CTRL_GATHER;
                else
                        new_ctrl &= ~NFP_NET_CFG_CTRL_GATHER;
        }

        nn_dbg(nn, "Feature change 0x%llx -> 0x%llx (changed=0x%llx)\n",
               netdev->features, features, changed);

        if (new_ctrl == nn->ctrl)
                return 0;

        nn_dbg(nn, "NIC ctrl: 0x%x -> 0x%x\n", nn->ctrl, new_ctrl);
        nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
        err = nfp_net_reconfig(nn, NFP_NET_CFG_UPDATE_GEN);
        if (err)
                return err;

        nn->ctrl = new_ctrl;

        return 0;
}

static netdev_features_t
nfp_net_features_check(struct sk_buff *skb, struct net_device *dev,
                       netdev_features_t features)
{
        u8 l4_hdr;

        /* We can't do TSO over double tagged packets (802.1AD) */
        features &= vlan_features_check(skb, features);

        if (!skb->encapsulation)
                return features;

        /* Ensure that inner L4 header offset fits into TX descriptor field */
        if (skb_is_gso(skb)) {
                u32 hdrlen;

                hdrlen = skb_inner_transport_header(skb) - skb->data +
                        inner_tcp_hdrlen(skb);

                if (unlikely(hdrlen > NFP_NET_LSO_MAX_HDR_SZ))
                        features &= ~NETIF_F_GSO_MASK;
        }

        /* VXLAN/GRE check */
        switch (vlan_get_protocol(skb)) {
        case htons(ETH_P_IP):
                l4_hdr = ip_hdr(skb)->protocol;
                break;
        case htons(ETH_P_IPV6):
                l4_hdr = ipv6_hdr(skb)->nexthdr;
                break;
        default:
                return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
        }

        if (skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
            skb->inner_protocol != htons(ETH_P_TEB) ||
            (l4_hdr != IPPROTO_UDP && l4_hdr != IPPROTO_GRE) ||
            (l4_hdr == IPPROTO_UDP &&
             (skb_inner_mac_header(skb) - skb_transport_header(skb) !=
              sizeof(struct udphdr) + sizeof(struct vxlanhdr))))
                return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);

        return features;
}

/**
 * nfp_net_set_vxlan_port() - set vxlan port in SW and reconfigure HW
 * @nn:   NFP Net device to reconfigure
 * @idx:  Index into the port table where new port should be written
 * @port: UDP port to configure (pass zero to remove VXLAN port)
 */
static void nfp_net_set_vxlan_port(struct nfp_net *nn, int idx, __be16 port)
{
        int i;

        nn->vxlan_ports[idx] = port;

        if (!(nn->ctrl & NFP_NET_CFG_CTRL_VXLAN))
                return;

        BUILD_BUG_ON(NFP_NET_N_VXLAN_PORTS & 1);
        for (i = 0; i < NFP_NET_N_VXLAN_PORTS; i += 2)
                nn_writel(nn, NFP_NET_CFG_VXLAN_PORT + i * sizeof(port),
                          be16_to_cpu(nn->vxlan_ports[i + 1]) << 16 |
                          be16_to_cpu(nn->vxlan_ports[i]));

        nfp_net_reconfig_post(nn, NFP_NET_CFG_UPDATE_VXLAN);
}

/**
 * nfp_net_find_vxlan_idx() - find table entry of the port or a free one
 * @nn:   NFP Network structure
 * @port: UDP port to look for
 *
 * Return: if the port is already in the table -- it's position;
 *         if the port is not in the table -- free position to use;
 *         if the table is full -- -ENOSPC.
 */
static int nfp_net_find_vxlan_idx(struct nfp_net *nn, __be16 port)
{
        int i, free_idx = -ENOSPC;

        for (i = 0; i < NFP_NET_N_VXLAN_PORTS; i++) {
                if (nn->vxlan_ports[i] == port)
                        return i;
                if (!nn->vxlan_usecnt[i])
                        free_idx = i;
        }

        return free_idx;
}

static void nfp_net_add_vxlan_port(struct net_device *netdev,
                                   sa_family_t sa_family, __be16 port)
{
        struct nfp_net *nn = netdev_priv(netdev);
        int idx;

        idx = nfp_net_find_vxlan_idx(nn, port);
        if (idx == -ENOSPC)
                return;

        if (!nn->vxlan_usecnt[idx]++)
                nfp_net_set_vxlan_port(nn, idx, port);
}

static void nfp_net_del_vxlan_port(struct net_device *netdev,
                                   sa_family_t sa_family, __be16 port)
{
        struct nfp_net *nn = netdev_priv(netdev);
        int idx;

        idx = nfp_net_find_vxlan_idx(nn, port);
        if (!nn->vxlan_usecnt[idx] || idx == -ENOSPC)
                return;

        if (!--nn->vxlan_usecnt[idx])
                nfp_net_set_vxlan_port(nn, idx, 0);
}

static const struct net_device_ops nfp_net_netdev_ops = {
        .ndo_open               = nfp_net_netdev_open,
        .ndo_stop               = nfp_net_netdev_close,
        .ndo_start_xmit         = nfp_net_tx,
        .ndo_get_stats64        = nfp_net_stat64,
        .ndo_tx_timeout         = nfp_net_tx_timeout,
        .ndo_set_rx_mode        = nfp_net_set_rx_mode,
        .ndo_change_mtu         = nfp_net_change_mtu,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_set_features       = nfp_net_set_features,
        .ndo_features_check     = nfp_net_features_check,
        .ndo_add_vxlan_port     = nfp_net_add_vxlan_port,
        .ndo_del_vxlan_port     = nfp_net_del_vxlan_port,
};

/**
 * nfp_net_info() - Print general info about the NIC
 * @nn:      NFP Net device to reconfigure
 */
void nfp_net_info(struct nfp_net *nn)
{
        nn_info(nn, "Netronome %s %sNetdev: TxQs=%d/%d RxQs=%d/%d\n",
                nn->is_nfp3200 ? "NFP-32xx" : "NFP-6xxx",
                nn->is_vf ? "VF " : "",
                nn->num_tx_rings, nn->max_tx_rings,
                nn->num_rx_rings, nn->max_rx_rings);
        nn_info(nn, "VER: %d.%d.%d.%d, Maximum supported MTU: %d\n",
                nn->fw_ver.resv, nn->fw_ver.class,
                nn->fw_ver.major, nn->fw_ver.minor,
                nn->max_mtu);
        nn_info(nn, "CAP: %#x %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
                nn->cap,
                nn->cap & NFP_NET_CFG_CTRL_PROMISC  ? "PROMISC "  : "",
                nn->cap & NFP_NET_CFG_CTRL_L2BC     ? "L2BCFILT " : "",
                nn->cap & NFP_NET_CFG_CTRL_L2MC     ? "L2MCFILT " : "",
                nn->cap & NFP_NET_CFG_CTRL_RXCSUM   ? "RXCSUM "   : "",
                nn->cap & NFP_NET_CFG_CTRL_TXCSUM   ? "TXCSUM "   : "",
                nn->cap & NFP_NET_CFG_CTRL_RXVLAN   ? "RXVLAN "   : "",
                nn->cap & NFP_NET_CFG_CTRL_TXVLAN   ? "TXVLAN "   : "",
                nn->cap & NFP_NET_CFG_CTRL_SCATTER  ? "SCATTER "  : "",
                nn->cap & NFP_NET_CFG_CTRL_GATHER   ? "GATHER "   : "",
                nn->cap & NFP_NET_CFG_CTRL_LSO      ? "TSO "      : "",
                nn->cap & NFP_NET_CFG_CTRL_RSS      ? "RSS "      : "",
                nn->cap & NFP_NET_CFG_CTRL_L2SWITCH ? "L2SWITCH " : "",
                nn->cap & NFP_NET_CFG_CTRL_MSIXAUTO ? "AUTOMASK " : "",
                nn->cap & NFP_NET_CFG_CTRL_IRQMOD   ? "IRQMOD "   : "",
                nn->cap & NFP_NET_CFG_CTRL_VXLAN    ? "VXLAN "    : "",
                nn->cap & NFP_NET_CFG_CTRL_NVGRE    ? "NVGRE "    : "");
}

/**
 * nfp_net_netdev_alloc() - Allocate netdev and related structure
 * @pdev:         PCI device
 * @max_tx_rings: Maximum number of TX rings supported by device
 * @max_rx_rings: Maximum number of RX rings supported by device
 *
 * This function allocates a netdev device and fills in the initial
 * part of the @struct nfp_net structure.
 *
 * Return: NFP Net device structure, or ERR_PTR on error.
 */
struct nfp_net *nfp_net_netdev_alloc(struct pci_dev *pdev,
                                     int max_tx_rings, int max_rx_rings)
{
        struct net_device *netdev;
        struct nfp_net *nn;
        int nqs;

        netdev = alloc_etherdev_mqs(sizeof(struct nfp_net),
                                    max_tx_rings, max_rx_rings);
        if (!netdev)
                return ERR_PTR(-ENOMEM);

        SET_NETDEV_DEV(netdev, &pdev->dev);
        nn = netdev_priv(netdev);

        nn->netdev = netdev;
        nn->pdev = pdev;

        nn->max_tx_rings = max_tx_rings;
        nn->max_rx_rings = max_rx_rings;

        nqs = netif_get_num_default_rss_queues();
        nn->num_tx_rings = min_t(int, nqs, max_tx_rings);
        nn->num_rx_rings = min_t(int, nqs, max_rx_rings);

        nn->txd_cnt = NFP_NET_TX_DESCS_DEFAULT;
        nn->rxd_cnt = NFP_NET_RX_DESCS_DEFAULT;

        spin_lock_init(&nn->reconfig_lock);
        spin_lock_init(&nn->link_status_lock);

        setup_timer(&nn->reconfig_timer,
                    nfp_net_reconfig_timer, (unsigned long)nn);

        return nn;
}

/**
 * nfp_net_netdev_free() - Undo what @nfp_net_netdev_alloc() did
 * @nn:      NFP Net device to reconfigure
 */
void nfp_net_netdev_free(struct nfp_net *nn)
{
        free_netdev(nn->netdev);
}

/**
 * nfp_net_rss_init() - Set the initial RSS parameters
 * @nn:      NFP Net device to reconfigure
 */
static void nfp_net_rss_init(struct nfp_net *nn)
{
        int i;

        netdev_rss_key_fill(nn->rss_key, NFP_NET_CFG_RSS_KEY_SZ);

        for (i = 0; i < sizeof(nn->rss_itbl); i++)
                nn->rss_itbl[i] =
                        ethtool_rxfh_indir_default(i, nn->num_rx_rings);

        /* Enable IPv4/IPv6 TCP by default */
        nn->rss_cfg = NFP_NET_CFG_RSS_IPV4_TCP |
                      NFP_NET_CFG_RSS_IPV6_TCP |
                      NFP_NET_CFG_RSS_TOEPLITZ |
                      NFP_NET_CFG_RSS_MASK;
}

/**
 * nfp_net_irqmod_init() - Set the initial IRQ moderation parameters
 * @nn:      NFP Net device to reconfigure
 */
static void nfp_net_irqmod_init(struct nfp_net *nn)
{
        nn->rx_coalesce_usecs      = 50;
        nn->rx_coalesce_max_frames = 64;
        nn->tx_coalesce_usecs      = 50;
        nn->tx_coalesce_max_frames = 64;
}

/**
 * nfp_net_netdev_init() - Initialise/finalise the netdev structure
 * @netdev:      netdev structure
 *
 * Return: 0 on success or negative errno on error.
 */
int nfp_net_netdev_init(struct net_device *netdev)
{
        struct nfp_net *nn = netdev_priv(netdev);
        int err;

        /* Get some of the read-only fields from the BAR */
        nn->cap = nn_readl(nn, NFP_NET_CFG_CAP);
        nn->max_mtu = nn_readl(nn, NFP_NET_CFG_MAX_MTU);

        nfp_net_write_mac_addr(nn, nn->netdev->dev_addr);

        /* Set default MTU and Freelist buffer size */
        if (nn->max_mtu < NFP_NET_DEFAULT_MTU)
                netdev->mtu = nn->max_mtu;
        else
                netdev->mtu = NFP_NET_DEFAULT_MTU;
        nn->fl_bufsz = NFP_NET_DEFAULT_RX_BUFSZ;

        /* Advertise/enable offloads based on capabilities
         *
         * Note: netdev->features show the currently enabled features
         * and netdev->hw_features advertises which features are
         * supported.  By default we enable most features.
         */
        netdev->hw_features = NETIF_F_HIGHDMA;
        if (nn->cap & NFP_NET_CFG_CTRL_RXCSUM) {
                netdev->hw_features |= NETIF_F_RXCSUM;
                nn->ctrl |= NFP_NET_CFG_CTRL_RXCSUM;
        }
        if (nn->cap & NFP_NET_CFG_CTRL_TXCSUM) {
                netdev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
                nn->ctrl |= NFP_NET_CFG_CTRL_TXCSUM;
        }
        if (nn->cap & NFP_NET_CFG_CTRL_GATHER) {
                netdev->hw_features |= NETIF_F_SG;
                nn->ctrl |= NFP_NET_CFG_CTRL_GATHER;
        }
        if ((nn->cap & NFP_NET_CFG_CTRL_LSO) && nn->fw_ver.major > 2) {
                netdev->hw_features |= NETIF_F_TSO | NETIF_F_TSO6;
                nn->ctrl |= NFP_NET_CFG_CTRL_LSO;
        }
        if (nn->cap & NFP_NET_CFG_CTRL_RSS) {
                netdev->hw_features |= NETIF_F_RXHASH;
                nfp_net_rss_init(nn);
                nn->ctrl |= NFP_NET_CFG_CTRL_RSS;
        }
        if (nn->cap & NFP_NET_CFG_CTRL_VXLAN &&
            nn->cap & NFP_NET_CFG_CTRL_NVGRE) {
                if (nn->cap & NFP_NET_CFG_CTRL_LSO)
                        netdev->hw_features |= NETIF_F_GSO_GRE |
                                               NETIF_F_GSO_UDP_TUNNEL;
                nn->ctrl |= NFP_NET_CFG_CTRL_VXLAN | NFP_NET_CFG_CTRL_NVGRE;

                netdev->hw_enc_features = netdev->hw_features;
        }

        netdev->vlan_features = netdev->hw_features;

        if (nn->cap & NFP_NET_CFG_CTRL_RXVLAN) {
                netdev->hw_features |= NETIF_F_HW_VLAN_CTAG_RX;
                nn->ctrl |= NFP_NET_CFG_CTRL_RXVLAN;
        }
        if (nn->cap & NFP_NET_CFG_CTRL_TXVLAN) {
                netdev->hw_features |= NETIF_F_HW_VLAN_CTAG_TX;
                nn->ctrl |= NFP_NET_CFG_CTRL_TXVLAN;
        }

        netdev->features = netdev->hw_features;

        /* Advertise but disable TSO by default. */
        netdev->features &= ~(NETIF_F_TSO | NETIF_F_TSO6);

        /* Allow L2 Broadcast and Multicast through by default, if supported */
        if (nn->cap & NFP_NET_CFG_CTRL_L2BC)
                nn->ctrl |= NFP_NET_CFG_CTRL_L2BC;
        if (nn->cap & NFP_NET_CFG_CTRL_L2MC)
                nn->ctrl |= NFP_NET_CFG_CTRL_L2MC;

        /* Allow IRQ moderation, if supported */
        if (nn->cap & NFP_NET_CFG_CTRL_IRQMOD) {
                nfp_net_irqmod_init(nn);
                nn->ctrl |= NFP_NET_CFG_CTRL_IRQMOD;
        }

        /* On NFP-3200 enable MSI-X auto-masking, if supported and the
         * interrupts are not shared.
         */
        if (nn->is_nfp3200 && nn->cap & NFP_NET_CFG_CTRL_MSIXAUTO)
                nn->ctrl |= NFP_NET_CFG_CTRL_MSIXAUTO;

        /* On NFP4000/NFP6000, determine RX packet/metadata boundary offset */
        if (nn->fw_ver.major >= 2)
                nn->rx_offset = nn_readl(nn, NFP_NET_CFG_RX_OFFSET);
        else
                nn->rx_offset = NFP_NET_RX_OFFSET;

        /* Stash the re-configuration queue away.  First odd queue in TX Bar */
        nn->qcp_cfg = nn->tx_bar + NFP_QCP_QUEUE_ADDR_SZ;

        /* Make sure the FW knows the netdev is supposed to be disabled here */
        nn_writel(nn, NFP_NET_CFG_CTRL, 0);
        nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, 0);
        nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, 0);
        err = nfp_net_reconfig(nn, NFP_NET_CFG_UPDATE_RING |
                                   NFP_NET_CFG_UPDATE_GEN);
        if (err)
                return err;

        /* Finalise the netdev setup */
        ether_setup(netdev);
        netdev->netdev_ops = &nfp_net_netdev_ops;
        netdev->watchdog_timeo = msecs_to_jiffies(5 * 1000);
        netif_carrier_off(netdev);

        nfp_net_set_ethtool_ops(netdev);
        nfp_net_irqs_assign(netdev);

        return register_netdev(netdev);
}

/**
 * nfp_net_netdev_clean() - Undo what nfp_net_netdev_init() did.
 * @netdev:      netdev structure
 */
void nfp_net_netdev_clean(struct net_device *netdev)
{
        unregister_netdev(netdev);
}