// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2018, Intel Corporation. */

/* The driver transmit and receive code */

#include <linux/mm.h>
#include <linux/netdevice.h>
#include <linux/prefetch.h>
#include <linux/bpf_trace.h>
#include <net/dsfield.h>
#include <net/mpls.h>
#include <net/xdp.h>
#include "ice_txrx_lib.h"
#include "ice_lib.h"
#include "ice.h"
#include "ice_trace.h"
#include "ice_dcb_lib.h"
#include "ice_xsk.h"
#include "ice_eswitch.h"

#define ICE_RX_HDR_SIZE         256

#define FDIR_DESC_RXDID 0x40
#define ICE_FDIR_CLEAN_DELAY 10

/**
 * ice_prgm_fdir_fltr - Program a Flow Director filter
 * @vsi: VSI to send dummy packet
 * @fdir_desc: flow director descriptor
 * @raw_packet: allocated buffer for flow director
 */
int
ice_prgm_fdir_fltr(struct ice_vsi *vsi, struct ice_fltr_desc *fdir_desc,
                   u8 *raw_packet)
{
        struct ice_tx_buf *tx_buf, *first;
        struct ice_fltr_desc *f_desc;
        struct ice_tx_desc *tx_desc;
        struct ice_tx_ring *tx_ring;
        struct device *dev;
        dma_addr_t dma;
        u32 td_cmd;
        u16 i;

        /* VSI and Tx ring */
        if (!vsi)
                return -ENOENT;
        tx_ring = vsi->tx_rings[0];
        if (!tx_ring || !tx_ring->desc)
                return -ENOENT;
        dev = tx_ring->dev;

        /* we are using two descriptors to add/del a filter and we can wait */
        for (i = ICE_FDIR_CLEAN_DELAY; ICE_DESC_UNUSED(tx_ring) < 2; i--) {
                if (!i)
                        return -EAGAIN;
                msleep_interruptible(1);
        }

        dma = dma_map_single(dev, raw_packet, ICE_FDIR_MAX_RAW_PKT_SIZE,
                             DMA_TO_DEVICE);

        if (dma_mapping_error(dev, dma))
                return -EINVAL;

        /* grab the next descriptor */
        i = tx_ring->next_to_use;
        first = &tx_ring->tx_buf[i];
        f_desc = ICE_TX_FDIRDESC(tx_ring, i);
        memcpy(f_desc, fdir_desc, sizeof(*f_desc));

        i++;
        i = (i < tx_ring->count) ? i : 0;
        tx_desc = ICE_TX_DESC(tx_ring, i);
        tx_buf = &tx_ring->tx_buf[i];

        i++;
        tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;

        memset(tx_buf, 0, sizeof(*tx_buf));
        dma_unmap_len_set(tx_buf, len, ICE_FDIR_MAX_RAW_PKT_SIZE);
        dma_unmap_addr_set(tx_buf, dma, dma);

        tx_desc->buf_addr = cpu_to_le64(dma);
        td_cmd = ICE_TXD_LAST_DESC_CMD | ICE_TX_DESC_CMD_DUMMY |
                 ICE_TX_DESC_CMD_RE;

        tx_buf->tx_flags = ICE_TX_FLAGS_DUMMY_PKT;
        tx_buf->raw_buf = raw_packet;

        tx_desc->cmd_type_offset_bsz =
                ice_build_ctob(td_cmd, 0, ICE_FDIR_MAX_RAW_PKT_SIZE, 0);

        /* Force memory write to complete before letting h/w know
         * there are new descriptors to fetch.
         */
        wmb();

        /* mark the data descriptor to be watched */
        first->next_to_watch = tx_desc;

        writel(tx_ring->next_to_use, tx_ring->tail);

        return 0;
}

/**
 * ice_unmap_and_free_tx_buf - Release a Tx buffer
 * @ring: the ring that owns the buffer
 * @tx_buf: the buffer to free
 */
static void
ice_unmap_and_free_tx_buf(struct ice_tx_ring *ring, struct ice_tx_buf *tx_buf)
{
        if (tx_buf->skb) {
                if (tx_buf->tx_flags & ICE_TX_FLAGS_DUMMY_PKT)
                        devm_kfree(ring->dev, tx_buf->raw_buf);
                else if (ice_ring_is_xdp(ring))
                        page_frag_free(tx_buf->raw_buf);
                else
                        dev_kfree_skb_any(tx_buf->skb);
                if (dma_unmap_len(tx_buf, len))
                        dma_unmap_single(ring->dev,
                                         dma_unmap_addr(tx_buf, dma),
                                         dma_unmap_len(tx_buf, len),
                                         DMA_TO_DEVICE);
        } else if (dma_unmap_len(tx_buf, len)) {
                dma_unmap_page(ring->dev,
                               dma_unmap_addr(tx_buf, dma),
                               dma_unmap_len(tx_buf, len),
                               DMA_TO_DEVICE);
        }

        tx_buf->next_to_watch = NULL;
        tx_buf->skb = NULL;
        dma_unmap_len_set(tx_buf, len, 0);
        /* tx_buf must be completely set up in the transmit path */
}

static struct netdev_queue *txring_txq(const struct ice_tx_ring *ring)
{
        return netdev_get_tx_queue(ring->netdev, ring->q_index);
}

/**
 * ice_clean_tx_ring - Free any empty Tx buffers
 * @tx_ring: ring to be cleaned
 */
void ice_clean_tx_ring(struct ice_tx_ring *tx_ring)
{
        u32 size;
        u16 i;

        if (ice_ring_is_xdp(tx_ring) && tx_ring->xsk_pool) {
                ice_xsk_clean_xdp_ring(tx_ring);
                goto tx_skip_free;
        }

        /* ring already cleared, nothing to do */
        if (!tx_ring->tx_buf)
                return;

        /* Free all the Tx ring sk_buffs */
        for (i = 0; i < tx_ring->count; i++)
                ice_unmap_and_free_tx_buf(tx_ring, &tx_ring->tx_buf[i]);

tx_skip_free:
        memset(tx_ring->tx_buf, 0, sizeof(*tx_ring->tx_buf) * tx_ring->count);

        size = ALIGN(tx_ring->count * sizeof(struct ice_tx_desc),
                     PAGE_SIZE);
        /* Zero out the descriptor ring */
        memset(tx_ring->desc, 0, size);

        tx_ring->next_to_use = 0;
        tx_ring->next_to_clean = 0;
        tx_ring->next_dd = ICE_RING_QUARTER(tx_ring) - 1;
        tx_ring->next_rs = ICE_RING_QUARTER(tx_ring) - 1;

        if (!tx_ring->netdev)
                return;

        /* cleanup Tx queue statistics */
        netdev_tx_reset_queue(txring_txq(tx_ring));
}

/**
 * ice_free_tx_ring - Free Tx resources per queue
 * @tx_ring: Tx descriptor ring for a specific queue
 *
 * Free all transmit software resources
 */
void ice_free_tx_ring(struct ice_tx_ring *tx_ring)
{
        u32 size;

        ice_clean_tx_ring(tx_ring);
        devm_kfree(tx_ring->dev, tx_ring->tx_buf);
        tx_ring->tx_buf = NULL;

        if (tx_ring->desc) {
                size = ALIGN(tx_ring->count * sizeof(struct ice_tx_desc),
                             PAGE_SIZE);
                dmam_free_coherent(tx_ring->dev, size,
                                   tx_ring->desc, tx_ring->dma);
                tx_ring->desc = NULL;
        }
}

/**
 * ice_clean_tx_irq - Reclaim resources after transmit completes
 * @tx_ring: Tx ring to clean
 * @napi_budget: Used to determine if we are in netpoll
 *
 * Returns true if there's any budget left (e.g. the clean is finished)
 */
static bool ice_clean_tx_irq(struct ice_tx_ring *tx_ring, int napi_budget)
{
        unsigned int total_bytes = 0, total_pkts = 0;
        unsigned int budget = ICE_DFLT_IRQ_WORK;
        struct ice_vsi *vsi = tx_ring->vsi;
        s16 i = tx_ring->next_to_clean;
        struct ice_tx_desc *tx_desc;
        struct ice_tx_buf *tx_buf;

        /* get the bql data ready */
        netdev_txq_bql_complete_prefetchw(txring_txq(tx_ring));

        tx_buf = &tx_ring->tx_buf[i];
        tx_desc = ICE_TX_DESC(tx_ring, i);
        i -= tx_ring->count;

        prefetch(&vsi->state);

        do {
                struct ice_tx_desc *eop_desc = tx_buf->next_to_watch;

                /* if next_to_watch is not set then there is no work pending */
                if (!eop_desc)
                        break;

                /* follow the guidelines of other drivers */
                prefetchw(&tx_buf->skb->users);

                smp_rmb();      /* prevent any other reads prior to eop_desc */

                ice_trace(clean_tx_irq, tx_ring, tx_desc, tx_buf);
                /* if the descriptor isn't done, no work yet to do */
                if (!(eop_desc->cmd_type_offset_bsz &
                      cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE)))
                        break;

                /* clear next_to_watch to prevent false hangs */
                tx_buf->next_to_watch = NULL;

                /* update the statistics for this packet */
                total_bytes += tx_buf->bytecount;
                total_pkts += tx_buf->gso_segs;

                /* free the skb */
                napi_consume_skb(tx_buf->skb, napi_budget);

                /* unmap skb header data */
                dma_unmap_single(tx_ring->dev,
                                 dma_unmap_addr(tx_buf, dma),
                                 dma_unmap_len(tx_buf, len),
                                 DMA_TO_DEVICE);

                /* clear tx_buf data */
                tx_buf->skb = NULL;
                dma_unmap_len_set(tx_buf, len, 0);

                /* unmap remaining buffers */
                while (tx_desc != eop_desc) {
                        ice_trace(clean_tx_irq_unmap, tx_ring, tx_desc, tx_buf);
                        tx_buf++;
                        tx_desc++;
                        i++;
                        if (unlikely(!i)) {
                                i -= tx_ring->count;
                                tx_buf = tx_ring->tx_buf;
                                tx_desc = ICE_TX_DESC(tx_ring, 0);
                        }

                        /* unmap any remaining paged data */
                        if (dma_unmap_len(tx_buf, len)) {
                                dma_unmap_page(tx_ring->dev,
                                               dma_unmap_addr(tx_buf, dma),
                                               dma_unmap_len(tx_buf, len),
                                               DMA_TO_DEVICE);
                                dma_unmap_len_set(tx_buf, len, 0);
                        }
                }
                ice_trace(clean_tx_irq_unmap_eop, tx_ring, tx_desc, tx_buf);

                /* move us one more past the eop_desc for start of next pkt */
                tx_buf++;
                tx_desc++;
                i++;
                if (unlikely(!i)) {
                        i -= tx_ring->count;
                        tx_buf = tx_ring->tx_buf;
                        tx_desc = ICE_TX_DESC(tx_ring, 0);
                }

                prefetch(tx_desc);

                /* update budget accounting */
                budget--;
        } while (likely(budget));

        i += tx_ring->count;
        tx_ring->next_to_clean = i;

        ice_update_tx_ring_stats(tx_ring, total_pkts, total_bytes);
        netdev_tx_completed_queue(txring_txq(tx_ring), total_pkts, total_bytes);

#define TX_WAKE_THRESHOLD ((s16)(DESC_NEEDED * 2))
        if (unlikely(total_pkts && netif_carrier_ok(tx_ring->netdev) &&
                     (ICE_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD))) {
                /* Make sure that anybody stopping the queue after this
                 * sees the new next_to_clean.
                 */
                smp_mb();
                if (netif_tx_queue_stopped(txring_txq(tx_ring)) &&
                    !test_bit(ICE_VSI_DOWN, vsi->state)) {
                        netif_tx_wake_queue(txring_txq(tx_ring));
                        ++tx_ring->tx_stats.restart_q;
                }
        }

        return !!budget;
}

/**
 * ice_setup_tx_ring - Allocate the Tx descriptors
 * @tx_ring: the Tx ring to set up
 *
 * Return 0 on success, negative on error
 */
int ice_setup_tx_ring(struct ice_tx_ring *tx_ring)
{
        struct device *dev = tx_ring->dev;
        u32 size;

        if (!dev)
                return -ENOMEM;

        /* warn if we are about to overwrite the pointer */
        WARN_ON(tx_ring->tx_buf);
        tx_ring->tx_buf =
                devm_kcalloc(dev, sizeof(*tx_ring->tx_buf), tx_ring->count,
                             GFP_KERNEL);
        if (!tx_ring->tx_buf)
                return -ENOMEM;

        /* round up to nearest page */
        size = ALIGN(tx_ring->count * sizeof(struct ice_tx_desc),
                     PAGE_SIZE);
        tx_ring->desc = dmam_alloc_coherent(dev, size, &tx_ring->dma,
                                            GFP_KERNEL);
        if (!tx_ring->desc) {
                dev_err(dev, "Unable to allocate memory for the Tx descriptor ring, size=%d\n",
                        size);
                goto err;
        }

        tx_ring->next_to_use = 0;
        tx_ring->next_to_clean = 0;
        tx_ring->tx_stats.prev_pkt = -1;
        return 0;

err:
        devm_kfree(dev, tx_ring->tx_buf);
        tx_ring->tx_buf = NULL;
        return -ENOMEM;
}

/**
 * ice_clean_rx_ring - Free Rx buffers
 * @rx_ring: ring to be cleaned
 */
void ice_clean_rx_ring(struct ice_rx_ring *rx_ring)
{
        struct device *dev = rx_ring->dev;
        u32 size;
        u16 i;

        /* ring already cleared, nothing to do */
        if (!rx_ring->rx_buf)
                return;

        if (rx_ring->skb) {
                dev_kfree_skb(rx_ring->skb);
                rx_ring->skb = NULL;
        }

        if (rx_ring->xsk_pool) {
                ice_xsk_clean_rx_ring(rx_ring);
                goto rx_skip_free;
        }

        /* Free all the Rx ring sk_buffs */
        for (i = 0; i < rx_ring->count; i++) {
                struct ice_rx_buf *rx_buf = &rx_ring->rx_buf[i];

                if (!rx_buf->page)
                        continue;

                /* Invalidate cache lines that may have been written to by
                 * device so that we avoid corrupting memory.
                 */
                dma_sync_single_range_for_cpu(dev, rx_buf->dma,
                                              rx_buf->page_offset,
                                              rx_ring->rx_buf_len,
                                              DMA_FROM_DEVICE);

                /* free resources associated with mapping */
                dma_unmap_page_attrs(dev, rx_buf->dma, ice_rx_pg_size(rx_ring),
                                     DMA_FROM_DEVICE, ICE_RX_DMA_ATTR);
                __page_frag_cache_drain(rx_buf->page, rx_buf->pagecnt_bias);

                rx_buf->page = NULL;
                rx_buf->page_offset = 0;
        }

rx_skip_free:
        if (rx_ring->xsk_pool)
                memset(rx_ring->xdp_buf, 0, array_size(rx_ring->count, sizeof(*rx_ring->xdp_buf)));
        else
                memset(rx_ring->rx_buf, 0, array_size(rx_ring->count, sizeof(*rx_ring->rx_buf)));

        /* Zero out the descriptor ring */
        size = ALIGN(rx_ring->count * sizeof(union ice_32byte_rx_desc),
                     PAGE_SIZE);
        memset(rx_ring->desc, 0, size);

        rx_ring->next_to_alloc = 0;
        rx_ring->next_to_clean = 0;
        rx_ring->next_to_use = 0;
}

/**
 * ice_free_rx_ring - Free Rx resources
 * @rx_ring: ring to clean the resources from
 *
 * Free all receive software resources
 */
void ice_free_rx_ring(struct ice_rx_ring *rx_ring)
{
        u32 size;

        ice_clean_rx_ring(rx_ring);
        if (rx_ring->vsi->type == ICE_VSI_PF)
                if (xdp_rxq_info_is_reg(&rx_ring->xdp_rxq))
                        xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
        rx_ring->xdp_prog = NULL;
        if (rx_ring->xsk_pool) {
                kfree(rx_ring->xdp_buf);
                rx_ring->xdp_buf = NULL;
        } else {
                kfree(rx_ring->rx_buf);
                rx_ring->rx_buf = NULL;
        }

        if (rx_ring->desc) {
                size = ALIGN(rx_ring->count * sizeof(union ice_32byte_rx_desc),
                             PAGE_SIZE);
                dmam_free_coherent(rx_ring->dev, size,
                                   rx_ring->desc, rx_ring->dma);
                rx_ring->desc = NULL;
        }
}

/**
 * ice_setup_rx_ring - Allocate the Rx descriptors
 * @rx_ring: the Rx ring to set up
 *
 * Return 0 on success, negative on error
 */
int ice_setup_rx_ring(struct ice_rx_ring *rx_ring)
{
        struct device *dev = rx_ring->dev;
        u32 size;

        if (!dev)
                return -ENOMEM;

        /* warn if we are about to overwrite the pointer */
        WARN_ON(rx_ring->rx_buf);
        rx_ring->rx_buf =
                kcalloc(rx_ring->count, sizeof(*rx_ring->rx_buf), GFP_KERNEL);
        if (!rx_ring->rx_buf)
                return -ENOMEM;

        /* round up to nearest page */
        size = ALIGN(rx_ring->count * sizeof(union ice_32byte_rx_desc),
                     PAGE_SIZE);
        rx_ring->desc = dmam_alloc_coherent(dev, size, &rx_ring->dma,
                                            GFP_KERNEL);
        if (!rx_ring->desc) {
                dev_err(dev, "Unable to allocate memory for the Rx descriptor ring, size=%d\n",
                        size);
                goto err;
        }

        rx_ring->next_to_use = 0;
        rx_ring->next_to_clean = 0;

        if (ice_is_xdp_ena_vsi(rx_ring->vsi))
                WRITE_ONCE(rx_ring->xdp_prog, rx_ring->vsi->xdp_prog);

        if (rx_ring->vsi->type == ICE_VSI_PF &&
            !xdp_rxq_info_is_reg(&rx_ring->xdp_rxq))
                if (xdp_rxq_info_reg(&rx_ring->xdp_rxq, rx_ring->netdev,
                                     rx_ring->q_index, rx_ring->q_vector->napi.napi_id))
                        goto err;
        return 0;

err:
        kfree(rx_ring->rx_buf);
        rx_ring->rx_buf = NULL;
        return -ENOMEM;
}

static unsigned int
ice_rx_frame_truesize(struct ice_rx_ring *rx_ring, unsigned int __maybe_unused size)
{
        unsigned int truesize;

#if (PAGE_SIZE < 8192)
        truesize = ice_rx_pg_size(rx_ring) / 2; /* Must be power-of-2 */
#else
        truesize = rx_ring->rx_offset ?
                SKB_DATA_ALIGN(rx_ring->rx_offset + size) +
                SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) :
                SKB_DATA_ALIGN(size);
#endif
        return truesize;
}

/**
 * ice_run_xdp - Executes an XDP program on initialized xdp_buff
 * @rx_ring: Rx ring
 * @xdp: xdp_buff used as input to the XDP program
 * @xdp_prog: XDP program to run
 * @xdp_ring: ring to be used for XDP_TX action
 *
 * Returns any of ICE_XDP_{PASS, CONSUMED, TX, REDIR}
 */
static int
ice_run_xdp(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
            struct bpf_prog *xdp_prog, struct ice_tx_ring *xdp_ring)
{
        int err;
        u32 act;

        act = bpf_prog_run_xdp(xdp_prog, xdp);
        switch (act) {
        case XDP_PASS:
                return ICE_XDP_PASS;
        case XDP_TX:
                if (static_branch_unlikely(&ice_xdp_locking_key))
                        spin_lock(&xdp_ring->tx_lock);
                err = ice_xmit_xdp_ring(xdp->data, xdp->data_end - xdp->data, xdp_ring);
                if (static_branch_unlikely(&ice_xdp_locking_key))
                        spin_unlock(&xdp_ring->tx_lock);
                if (err == ICE_XDP_CONSUMED)
                        goto out_failure;
                return err;
        case XDP_REDIRECT:
                err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog);
                if (err)
                        goto out_failure;
                return ICE_XDP_REDIR;
        default:
                bpf_warn_invalid_xdp_action(rx_ring->netdev, xdp_prog, act);
                fallthrough;
        case XDP_ABORTED:
out_failure:
                trace_xdp_exception(rx_ring->netdev, xdp_prog, act);
                fallthrough;
        case XDP_DROP:
                return ICE_XDP_CONSUMED;
        }
}

/**
 * ice_xdp_xmit - submit packets to XDP ring for transmission
 * @dev: netdev
 * @n: number of XDP frames to be transmitted
 * @frames: XDP frames to be transmitted
 * @flags: transmit flags
 *
 * Returns number of frames successfully sent. Failed frames
 * will be free'ed by XDP core.
 * For error cases, a negative errno code is returned and no-frames
 * are transmitted (caller must handle freeing frames).
 */
int
ice_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
             u32 flags)
{
        struct ice_netdev_priv *np = netdev_priv(dev);
        unsigned int queue_index = smp_processor_id();
        struct ice_vsi *vsi = np->vsi;
        struct ice_tx_ring *xdp_ring;
        int nxmit = 0, i;

        if (test_bit(ICE_VSI_DOWN, vsi->state))
                return -ENETDOWN;

        if (!ice_is_xdp_ena_vsi(vsi) || queue_index >= vsi->num_xdp_txq)
                return -ENXIO;

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

        if (static_branch_unlikely(&ice_xdp_locking_key)) {
                queue_index %= vsi->num_xdp_txq;
                xdp_ring = vsi->xdp_rings[queue_index];
                spin_lock(&xdp_ring->tx_lock);
        } else {
                xdp_ring = vsi->xdp_rings[queue_index];
        }

        for (i = 0; i < n; i++) {
                struct xdp_frame *xdpf = frames[i];
                int err;

                err = ice_xmit_xdp_ring(xdpf->data, xdpf->len, xdp_ring);
                if (err != ICE_XDP_TX)
                        break;
                nxmit++;
        }

        if (unlikely(flags & XDP_XMIT_FLUSH))
                ice_xdp_ring_update_tail(xdp_ring);

        if (static_branch_unlikely(&ice_xdp_locking_key))
                spin_unlock(&xdp_ring->tx_lock);

        return nxmit;
}

/**
 * ice_alloc_mapped_page - recycle or make a new page
 * @rx_ring: ring to use
 * @bi: rx_buf struct to modify
 *
 * Returns true if the page was successfully allocated or
 * reused.
 */
static bool
ice_alloc_mapped_page(struct ice_rx_ring *rx_ring, struct ice_rx_buf *bi)
{
        struct page *page = bi->page;
        dma_addr_t dma;

        /* since we are recycling buffers we should seldom need to alloc */
        if (likely(page))
                return true;

        /* alloc new page for storage */
        page = dev_alloc_pages(ice_rx_pg_order(rx_ring));
        if (unlikely(!page)) {
                rx_ring->rx_stats.alloc_page_failed++;
                return false;
        }

        /* map page for use */
        dma = dma_map_page_attrs(rx_ring->dev, page, 0, ice_rx_pg_size(rx_ring),
                                 DMA_FROM_DEVICE, ICE_RX_DMA_ATTR);

        /* if mapping failed free memory back to system since
         * there isn't much point in holding memory we can't use
         */
        if (dma_mapping_error(rx_ring->dev, dma)) {
                __free_pages(page, ice_rx_pg_order(rx_ring));
                rx_ring->rx_stats.alloc_page_failed++;
                return false;
        }

        bi->dma = dma;
        bi->page = page;
        bi->page_offset = rx_ring->rx_offset;
        page_ref_add(page, USHRT_MAX - 1);
        bi->pagecnt_bias = USHRT_MAX;

        return true;
}

/**
 * ice_alloc_rx_bufs - Replace used receive buffers
 * @rx_ring: ring to place buffers on
 * @cleaned_count: number of buffers to replace
 *
 * Returns false if all allocations were successful, true if any fail. Returning
 * true signals to the caller that we didn't replace cleaned_count buffers and
 * there is more work to do.
 *
 * First, try to clean "cleaned_count" Rx buffers. Then refill the cleaned Rx
 * buffers. Then bump tail at most one time. Grouping like this lets us avoid
 * multiple tail writes per call.
 */
bool ice_alloc_rx_bufs(struct ice_rx_ring *rx_ring, u16 cleaned_count)
{
        union ice_32b_rx_flex_desc *rx_desc;
        u16 ntu = rx_ring->next_to_use;
        struct ice_rx_buf *bi;

        /* do nothing if no valid netdev defined */
        if ((!rx_ring->netdev && rx_ring->vsi->type != ICE_VSI_CTRL) ||
            !cleaned_count)
                return false;

        /* get the Rx descriptor and buffer based on next_to_use */
        rx_desc = ICE_RX_DESC(rx_ring, ntu);
        bi = &rx_ring->rx_buf[ntu];

        do {
                /* if we fail here, we have work remaining */
                if (!ice_alloc_mapped_page(rx_ring, bi))
                        break;

                /* sync the buffer for use by the device */
                dma_sync_single_range_for_device(rx_ring->dev, bi->dma,
                                                 bi->page_offset,
                                                 rx_ring->rx_buf_len,
                                                 DMA_FROM_DEVICE);

                /* Refresh the desc even if buffer_addrs didn't change
                 * because each write-back erases this info.
                 */
                rx_desc->read.pkt_addr = cpu_to_le64(bi->dma + bi->page_offset);

                rx_desc++;
                bi++;
                ntu++;
                if (unlikely(ntu == rx_ring->count)) {
                        rx_desc = ICE_RX_DESC(rx_ring, 0);
                        bi = rx_ring->rx_buf;
                        ntu = 0;
                }

                /* clear the status bits for the next_to_use descriptor */
                rx_desc->wb.status_error0 = 0;

                cleaned_count--;
        } while (cleaned_count);

        if (rx_ring->next_to_use != ntu)
                ice_release_rx_desc(rx_ring, ntu);

        return !!cleaned_count;
}

/**
 * ice_rx_buf_adjust_pg_offset - Prepare Rx buffer for reuse
 * @rx_buf: Rx buffer to adjust
 * @size: Size of adjustment
 *
 * Update the offset within page so that Rx buf will be ready to be reused.
 * For systems with PAGE_SIZE < 8192 this function will flip the page offset
 * so the second half of page assigned to Rx buffer will be used, otherwise
 * the offset is moved by "size" bytes
 */
static void
ice_rx_buf_adjust_pg_offset(struct ice_rx_buf *rx_buf, unsigned int size)
{
#if (PAGE_SIZE < 8192)
        /* flip page offset to other buffer */
        rx_buf->page_offset ^= size;
#else
        /* move offset up to the next cache line */
        rx_buf->page_offset += size;
#endif
}

/**
 * ice_can_reuse_rx_page - Determine if page can be reused for another Rx
 * @rx_buf: buffer containing the page
 * @rx_buf_pgcnt: rx_buf page refcount pre xdp_do_redirect() call
 *
 * If page is reusable, we have a green light for calling ice_reuse_rx_page,
 * which will assign the current buffer to the buffer that next_to_alloc is
 * pointing to; otherwise, the DMA mapping needs to be destroyed and
 * page freed
 */
static bool
ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf, int rx_buf_pgcnt)
{
        unsigned int pagecnt_bias = rx_buf->pagecnt_bias;
        struct page *page = rx_buf->page;

        /* avoid re-using remote and pfmemalloc pages */
        if (!dev_page_is_reusable(page))
                return false;

#if (PAGE_SIZE < 8192)
        /* if we are only owner of page we can reuse it */
        if (unlikely((rx_buf_pgcnt - pagecnt_bias) > 1))
                return false;
#else
#define ICE_LAST_OFFSET \
        (SKB_WITH_OVERHEAD(PAGE_SIZE) - ICE_RXBUF_2048)
        if (rx_buf->page_offset > ICE_LAST_OFFSET)
                return false;
#endif /* PAGE_SIZE < 8192) */

        /* If we have drained the page fragment pool we need to update
         * the pagecnt_bias and page count so that we fully restock the
         * number of references the driver holds.
         */
        if (unlikely(pagecnt_bias == 1)) {
                page_ref_add(page, USHRT_MAX - 1);
                rx_buf->pagecnt_bias = USHRT_MAX;
        }

        return true;
}

/**
 * ice_add_rx_frag - Add contents of Rx buffer to sk_buff as a frag
 * @rx_ring: Rx descriptor ring to transact packets on
 * @rx_buf: buffer containing page to add
 * @skb: sk_buff to place the data into
 * @size: packet length from rx_desc
 *
 * This function will add the data contained in rx_buf->page to the skb.
 * It will just attach the page as a frag to the skb.
 * The function will then update the page offset.
 */
static void
ice_add_rx_frag(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf,
                struct sk_buff *skb, unsigned int size)
{
#if (PAGE_SIZE >= 8192)
        unsigned int truesize = SKB_DATA_ALIGN(size + rx_ring->rx_offset);
#else
        unsigned int truesize = ice_rx_pg_size(rx_ring) / 2;
#endif

        if (!size)
                return;
        skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buf->page,
                        rx_buf->page_offset, size, truesize);

        /* page is being used so we must update the page offset */
        ice_rx_buf_adjust_pg_offset(rx_buf, truesize);
}

/**
 * ice_reuse_rx_page - page flip buffer and store it back on the ring
 * @rx_ring: Rx descriptor ring to store buffers on
 * @old_buf: donor buffer to have page reused
 *
 * Synchronizes page for reuse by the adapter
 */
static void
ice_reuse_rx_page(struct ice_rx_ring *rx_ring, struct ice_rx_buf *old_buf)
{
        u16 nta = rx_ring->next_to_alloc;
        struct ice_rx_buf *new_buf;

        new_buf = &rx_ring->rx_buf[nta];

        /* update, and store next to alloc */
        nta++;
        rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;

        /* Transfer page from old buffer to new buffer.
         * Move each member individually to avoid possible store
         * forwarding stalls and unnecessary copy of skb.
         */
        new_buf->dma = old_buf->dma;
        new_buf->page = old_buf->page;
        new_buf->page_offset = old_buf->page_offset;
        new_buf->pagecnt_bias = old_buf->pagecnt_bias;
}

/**
 * ice_get_rx_buf - Fetch Rx buffer and synchronize data for use
 * @rx_ring: Rx descriptor ring to transact packets on
 * @size: size of buffer to add to skb
 * @rx_buf_pgcnt: rx_buf page refcount
 *
 * This function will pull an Rx buffer from the ring and synchronize it
 * for use by the CPU.
 */
static struct ice_rx_buf *
ice_get_rx_buf(struct ice_rx_ring *rx_ring, const unsigned int size,
               int *rx_buf_pgcnt)
{
        struct ice_rx_buf *rx_buf;

        rx_buf = &rx_ring->rx_buf[rx_ring->next_to_clean];
        *rx_buf_pgcnt =
#if (PAGE_SIZE < 8192)
                page_count(rx_buf->page);
#else
                0;
#endif
        prefetchw(rx_buf->page);

        if (!size)
                return rx_buf;
        /* we are reusing so sync this buffer for CPU use */
        dma_sync_single_range_for_cpu(rx_ring->dev, rx_buf->dma,
                                      rx_buf->page_offset, size,
                                      DMA_FROM_DEVICE);

        /* We have pulled a buffer for use, so decrement pagecnt_bias */
        rx_buf->pagecnt_bias--;

        return rx_buf;
}

/**
 * ice_build_skb - Build skb around an existing buffer
 * @rx_ring: Rx descriptor ring to transact packets on
 * @rx_buf: Rx buffer to pull data from
 * @xdp: xdp_buff pointing to the data
 *
 * This function builds an skb around an existing Rx buffer, taking care
 * to set up the skb correctly and avoid any memcpy overhead.
 */
static struct sk_buff *
ice_build_skb(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf,
              struct xdp_buff *xdp)
{
        u8 metasize = xdp->data - xdp->data_meta;
#if (PAGE_SIZE < 8192)
        unsigned int truesize = ice_rx_pg_size(rx_ring) / 2;
#else
        unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
                                SKB_DATA_ALIGN(xdp->data_end -
                                               xdp->data_hard_start);
#endif
        struct sk_buff *skb;

        /* Prefetch first cache line of first page. If xdp->data_meta
         * is unused, this points exactly as xdp->data, otherwise we
         * likely have a consumer accessing first few bytes of meta
         * data, and then actual data.
         */
        net_prefetch(xdp->data_meta);
        /* build an skb around the page buffer */
        skb = napi_build_skb(xdp->data_hard_start, truesize);
        if (unlikely(!skb))
                return NULL;

        /* must to record Rx queue, otherwise OS features such as
         * symmetric queue won't work
         */
        skb_record_rx_queue(skb, rx_ring->q_index);

        /* update pointers within the skb to store the data */
        skb_reserve(skb, xdp->data - xdp->data_hard_start);
        __skb_put(skb, xdp->data_end - xdp->data);
        if (metasize)
                skb_metadata_set(skb, metasize);

        /* buffer is used by skb, update page_offset */
        ice_rx_buf_adjust_pg_offset(rx_buf, truesize);

        return skb;
}

/**
 * ice_construct_skb - Allocate skb and populate it
 * @rx_ring: Rx descriptor ring to transact packets on
 * @rx_buf: Rx buffer to pull data from
 * @xdp: xdp_buff pointing to the data
 *
 * This function allocates an skb. It then populates it with the page
 * data from the current receive descriptor, taking care to set up the
 * skb correctly.
 */
static struct sk_buff *
ice_construct_skb(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf,
                  struct xdp_buff *xdp)
{
        unsigned int metasize = xdp->data - xdp->data_meta;
        unsigned int size = xdp->data_end - xdp->data;
        unsigned int headlen;
        struct sk_buff *skb;

        /* prefetch first cache line of first page */
        net_prefetch(xdp->data_meta);

        /* allocate a skb to store the frags */
        skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
                               ICE_RX_HDR_SIZE + metasize,
                               GFP_ATOMIC | __GFP_NOWARN);
        if (unlikely(!skb))
                return NULL;

        skb_record_rx_queue(skb, rx_ring->q_index);
        /* Determine available headroom for copy */

        headlen = size;
        if (headlen > ICE_RX_HDR_SIZE)
                headlen = eth_get_headlen(skb->dev, xdp->data, ICE_RX_HDR_SIZE);

        /* align pull length to size of long to optimize memcpy performance */
        memcpy(__skb_put(skb, headlen + metasize), xdp->data_meta,
               ALIGN(headlen + metasize, sizeof(long)));

        if (metasize) {
                skb_metadata_set(skb, metasize);
                __skb_pull(skb, metasize);
        }

        /* if we exhaust the linear part then add what is left as a frag */
        size -= headlen;
        if (size) {
#if (PAGE_SIZE >= 8192)
                unsigned int truesize = SKB_DATA_ALIGN(size);
#else
                unsigned int truesize = ice_rx_pg_size(rx_ring) / 2;
#endif
                skb_add_rx_frag(skb, 0, rx_buf->page,
                                rx_buf->page_offset + headlen, size, truesize);
                /* buffer is used by skb, update page_offset */
                ice_rx_buf_adjust_pg_offset(rx_buf, truesize);
        } else {
                /* buffer is unused, reset bias back to rx_buf; data was copied
                 * onto skb's linear part so there's no need for adjusting
                 * page offset and we can reuse this buffer as-is
                 */
                rx_buf->pagecnt_bias++;
        }

        return skb;
}

/**
 * ice_put_rx_buf - Clean up used buffer and either recycle or free
 * @rx_ring: Rx descriptor ring to transact packets on
 * @rx_buf: Rx buffer to pull data from
 * @rx_buf_pgcnt: Rx buffer page count pre xdp_do_redirect()
 *
 * This function will update next_to_clean and then clean up the contents
 * of the rx_buf. It will either recycle the buffer or unmap it and free
 * the associated resources.
 */
static void
ice_put_rx_buf(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf,
               int rx_buf_pgcnt)
{
        u16 ntc = rx_ring->next_to_clean + 1;

        /* fetch, update, and store next to clean */
        ntc = (ntc < rx_ring->count) ? ntc : 0;
        rx_ring->next_to_clean = ntc;

        if (!rx_buf)
                return;

        if (ice_can_reuse_rx_page(rx_buf, rx_buf_pgcnt)) {
                /* hand second half of page back to the ring */
                ice_reuse_rx_page(rx_ring, rx_buf);
        } else {
                /* we are not reusing the buffer so unmap it */
                dma_unmap_page_attrs(rx_ring->dev, rx_buf->dma,
                                     ice_rx_pg_size(rx_ring), DMA_FROM_DEVICE,
                                     ICE_RX_DMA_ATTR);
                __page_frag_cache_drain(rx_buf->page, rx_buf->pagecnt_bias);
        }

        /* clear contents of buffer_info */
        rx_buf->page = NULL;
}

/**
 * ice_is_non_eop - process handling of non-EOP buffers
 * @rx_ring: Rx ring being processed
 * @rx_desc: Rx descriptor for current buffer
 *
 * If the buffer is an EOP buffer, this function exits returning false,
 * otherwise return true indicating that this is in fact a non-EOP buffer.
 */
static bool
ice_is_non_eop(struct ice_rx_ring *rx_ring, union ice_32b_rx_flex_desc *rx_desc)
{
        /* if we are the last buffer then there is nothing else to do */
#define ICE_RXD_EOF BIT(ICE_RX_FLEX_DESC_STATUS0_EOF_S)
        if (likely(ice_test_staterr(rx_desc->wb.status_error0, ICE_RXD_EOF)))
                return false;

        rx_ring->rx_stats.non_eop_descs++;

        return true;
}

/**
 * ice_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
 * @rx_ring: Rx descriptor ring to transact packets on
 * @budget: Total limit on number of packets to process
 *
 * This function provides a "bounce buffer" approach to Rx interrupt
 * processing. The advantage to this is that on systems that have
 * expensive overhead for IOMMU access this provides a means of avoiding
 * it by maintaining the mapping of the page to the system.
 *
 * Returns amount of work completed
 */
int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
{
        unsigned int total_rx_bytes = 0, total_rx_pkts = 0, frame_sz = 0;
        u16 cleaned_count = ICE_DESC_UNUSED(rx_ring);
        unsigned int offset = rx_ring->rx_offset;
        struct ice_tx_ring *xdp_ring = NULL;
        unsigned int xdp_res, xdp_xmit = 0;
        struct sk_buff *skb = rx_ring->skb;
        struct bpf_prog *xdp_prog = NULL;
        struct xdp_buff xdp;
        bool failure;

        /* Frame size depend on rx_ring setup when PAGE_SIZE=4K */
#if (PAGE_SIZE < 8192)
        frame_sz = ice_rx_frame_truesize(rx_ring, 0);
#endif
        xdp_init_buff(&xdp, frame_sz, &rx_ring->xdp_rxq);

        xdp_prog = READ_ONCE(rx_ring->xdp_prog);
        if (xdp_prog)
                xdp_ring = rx_ring->xdp_ring;

        /* start the loop to process Rx packets bounded by 'budget' */
        while (likely(total_rx_pkts < (unsigned int)budget)) {
                union ice_32b_rx_flex_desc *rx_desc;
                struct ice_rx_buf *rx_buf;
                unsigned char *hard_start;
                unsigned int size;
                u16 stat_err_bits;
                int rx_buf_pgcnt;
                u16 vlan_tag = 0;
                u16 rx_ptype;

                /* get the Rx desc from Rx ring based on 'next_to_clean' */
                rx_desc = ICE_RX_DESC(rx_ring, rx_ring->next_to_clean);

                /* status_error_len will always be zero for unused descriptors
                 * because it's cleared in cleanup, and overlaps with hdr_addr
                 * which is always zero because packet split isn't used, if the
                 * hardware wrote DD then it will be non-zero
                 */
                stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_DD_S);
                if (!ice_test_staterr(rx_desc->wb.status_error0, stat_err_bits))
                        break;

                /* This memory barrier is needed to keep us from reading
                 * any other fields out of the rx_desc until we know the
                 * DD bit is set.
                 */
                dma_rmb();

                ice_trace(clean_rx_irq, rx_ring, rx_desc);
                if (rx_desc->wb.rxdid == FDIR_DESC_RXDID || !rx_ring->netdev) {
                        struct ice_vsi *ctrl_vsi = rx_ring->vsi;

                        if (rx_desc->wb.rxdid == FDIR_DESC_RXDID &&
                            ctrl_vsi->vf)
                                ice_vc_fdir_irq_handler(ctrl_vsi, rx_desc);
                        ice_put_rx_buf(rx_ring, NULL, 0);
                        cleaned_count++;
                        continue;
                }

                size = le16_to_cpu(rx_desc->wb.pkt_len) &
                        ICE_RX_FLX_DESC_PKT_LEN_M;

                /* retrieve a buffer from the ring */
                rx_buf = ice_get_rx_buf(rx_ring, size, &rx_buf_pgcnt);

                if (!size) {
                        xdp.data = NULL;
                        xdp.data_end = NULL;
                        xdp.data_hard_start = NULL;
                        xdp.data_meta = NULL;
                        goto construct_skb;
                }

                hard_start = page_address(rx_buf->page) + rx_buf->page_offset -
                             offset;
                xdp_prepare_buff(&xdp, hard_start, offset, size, true);
#if (PAGE_SIZE > 4096)
                /* At larger PAGE_SIZE, frame_sz depend on len size */
                xdp.frame_sz = ice_rx_frame_truesize(rx_ring, size);
#endif

                if (!xdp_prog)
                        goto construct_skb;

                xdp_res = ice_run_xdp(rx_ring, &xdp, xdp_prog, xdp_ring);
                if (!xdp_res)
                        goto construct_skb;
                if (xdp_res & (ICE_XDP_TX | ICE_XDP_REDIR)) {
                        xdp_xmit |= xdp_res;
                        ice_rx_buf_adjust_pg_offset(rx_buf, xdp.frame_sz);
                } else {
                        rx_buf->pagecnt_bias++;
                }
                total_rx_bytes += size;
                total_rx_pkts++;

                cleaned_count++;
                ice_put_rx_buf(rx_ring, rx_buf, rx_buf_pgcnt);
                continue;
construct_skb:
                if (skb) {
                        ice_add_rx_frag(rx_ring, rx_buf, skb, size);
                } else if (likely(xdp.data)) {
                        if (ice_ring_uses_build_skb(rx_ring))
                                skb = ice_build_skb(rx_ring, rx_buf, &xdp);
                        else
                                skb = ice_construct_skb(rx_ring, rx_buf, &xdp);
                }
                /* exit if we failed to retrieve a buffer */
                if (!skb) {
                        rx_ring->rx_stats.alloc_buf_failed++;
                        if (rx_buf)
                                rx_buf->pagecnt_bias++;
                        break;
                }

                ice_put_rx_buf(rx_ring, rx_buf, rx_buf_pgcnt);
                cleaned_count++;

                /* skip if it is NOP desc */
                if (ice_is_non_eop(rx_ring, rx_desc))
                        continue;

                stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_RXE_S);
                if (unlikely(ice_test_staterr(rx_desc->wb.status_error0,
                                              stat_err_bits))) {
                        dev_kfree_skb_any(skb);
                        continue;
                }

                vlan_tag = ice_get_vlan_tag_from_rx_desc(rx_desc);

                /* pad the skb if needed, to make a valid ethernet frame */
                if (eth_skb_pad(skb)) {
                        skb = NULL;
                        continue;
                }

                /* probably a little skewed due to removing CRC */
                total_rx_bytes += skb->len;

                /* populate checksum, VLAN, and protocol */
                rx_ptype = le16_to_cpu(rx_desc->wb.ptype_flex_flags0) &
                        ICE_RX_FLEX_DESC_PTYPE_M;

                ice_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype);

                ice_trace(clean_rx_irq_indicate, rx_ring, rx_desc, skb);
                /* send completed skb up the stack */
                ice_receive_skb(rx_ring, skb, vlan_tag);
                skb = NULL;

                /* update budget accounting */
                total_rx_pkts++;
        }

        /* return up to cleaned_count buffers to hardware */
        failure = ice_alloc_rx_bufs(rx_ring, cleaned_count);

        if (xdp_prog)
                ice_finalize_xdp_rx(xdp_ring, xdp_xmit);
        rx_ring->skb = skb;

        ice_update_rx_ring_stats(rx_ring, total_rx_pkts, total_rx_bytes);

        /* guarantee a trip back through this routine if there was a failure */
        return failure ? budget : (int)total_rx_pkts;
}

static void __ice_update_sample(struct ice_q_vector *q_vector,
                                struct ice_ring_container *rc,
                                struct dim_sample *sample,
                                bool is_tx)
{
        u64 packets = 0, bytes = 0;

        if (is_tx) {
                struct ice_tx_ring *tx_ring;

                ice_for_each_tx_ring(tx_ring, *rc) {
                        packets += tx_ring->stats.pkts;
                        bytes += tx_ring->stats.bytes;
                }
        } else {
                struct ice_rx_ring *rx_ring;

                ice_for_each_rx_ring(rx_ring, *rc) {
                        packets += rx_ring->stats.pkts;
                        bytes += rx_ring->stats.bytes;
                }
        }

        dim_update_sample(q_vector->total_events, packets, bytes, sample);
        sample->comp_ctr = 0;

        /* if dim settings get stale, like when not updated for 1
         * second or longer, force it to start again. This addresses the
         * frequent case of an idle queue being switched to by the
         * scheduler. The 1,000 here means 1,000 milliseconds.
         */
        if (ktime_ms_delta(sample->time, rc->dim.start_sample.time) >= 1000)
                rc->dim.state = DIM_START_MEASURE;
}

/**
 * ice_net_dim - Update net DIM algorithm
 * @q_vector: the vector associated with the interrupt
 *
 * Create a DIM sample and notify net_dim() so that it can possibly decide
 * a new ITR value based on incoming packets, bytes, and interrupts.
 *
 * This function is a no-op if the ring is not configured to dynamic ITR.
 */
static void ice_net_dim(struct ice_q_vector *q_vector)
{
        struct ice_ring_container *tx = &q_vector->tx;
        struct ice_ring_container *rx = &q_vector->rx;

        if (ITR_IS_DYNAMIC(tx)) {
                struct dim_sample dim_sample;

                __ice_update_sample(q_vector, tx, &dim_sample, true);
                net_dim(&tx->dim, dim_sample);
        }

        if (ITR_IS_DYNAMIC(rx)) {
                struct dim_sample dim_sample;

                __ice_update_sample(q_vector, rx, &dim_sample, false);
                net_dim(&rx->dim, dim_sample);
        }
}

/**
 * ice_buildreg_itr - build value for writing to the GLINT_DYN_CTL register
 * @itr_idx: interrupt throttling index
 * @itr: interrupt throttling value in usecs
 */
static u32 ice_buildreg_itr(u16 itr_idx, u16 itr)
{
        /* The ITR value is reported in microseconds, and the register value is
         * recorded in 2 microsecond units. For this reason we only need to
         * shift by the GLINT_DYN_CTL_INTERVAL_S - ICE_ITR_GRAN_S to apply this
         * granularity as a shift instead of division. The mask makes sure the
         * ITR value is never odd so we don't accidentally write into the field
         * prior to the ITR field.
         */
        itr &= ICE_ITR_MASK;

        return GLINT_DYN_CTL_INTENA_M | GLINT_DYN_CTL_CLEARPBA_M |
                (itr_idx << GLINT_DYN_CTL_ITR_INDX_S) |
                (itr << (GLINT_DYN_CTL_INTERVAL_S - ICE_ITR_GRAN_S));
}

/**
 * ice_enable_interrupt - re-enable MSI-X interrupt
 * @q_vector: the vector associated with the interrupt to enable
 *
 * If the VSI is down, the interrupt will not be re-enabled. Also,
 * when enabling the interrupt always reset the wb_on_itr to false
 * and trigger a software interrupt to clean out internal state.
 */
static void ice_enable_interrupt(struct ice_q_vector *q_vector)
{
        struct ice_vsi *vsi = q_vector->vsi;
        bool wb_en = q_vector->wb_on_itr;
        u32 itr_val;

        if (test_bit(ICE_DOWN, vsi->state))
                return;

        /* trigger an ITR delayed software interrupt when exiting busy poll, to
         * make sure to catch any pending cleanups that might have been missed
         * due to interrupt state transition. If busy poll or poll isn't
         * enabled, then don't update ITR, and just enable the interrupt.
         */
        if (!wb_en) {
                itr_val = ice_buildreg_itr(ICE_ITR_NONE, 0);
        } else {
                q_vector->wb_on_itr = false;

                /* do two things here with a single write. Set up the third ITR
                 * index to be used for software interrupt moderation, and then
                 * trigger a software interrupt with a rate limit of 20K on
                 * software interrupts, this will help avoid high interrupt
                 * loads due to frequently polling and exiting polling.
                 */
                itr_val = ice_buildreg_itr(ICE_IDX_ITR2, ICE_ITR_20K);
                itr_val |= GLINT_DYN_CTL_SWINT_TRIG_M |
                           ICE_IDX_ITR2 << GLINT_DYN_CTL_SW_ITR_INDX_S |
                           GLINT_DYN_CTL_SW_ITR_INDX_ENA_M;
        }
        wr32(&vsi->back->hw, GLINT_DYN_CTL(q_vector->reg_idx), itr_val);
}

/**
 * ice_set_wb_on_itr - set WB_ON_ITR for this q_vector
 * @q_vector: q_vector to set WB_ON_ITR on
 *
 * We need to tell hardware to write-back completed descriptors even when
 * interrupts are disabled. Descriptors will be written back on cache line
 * boundaries without WB_ON_ITR enabled, but if we don't enable WB_ON_ITR
 * descriptors may not be written back if they don't fill a cache line until
 * the next interrupt.
 *
 * This sets the write-back frequency to whatever was set previously for the
 * ITR indices. Also, set the INTENA_MSK bit to make sure hardware knows we
 * aren't meddling with the INTENA_M bit.
 */
static void ice_set_wb_on_itr(struct ice_q_vector *q_vector)
{
        struct ice_vsi *vsi = q_vector->vsi;

        /* already in wb_on_itr mode no need to change it */
        if (q_vector->wb_on_itr)
                return;

        /* use previously set ITR values for all of the ITR indices by
         * specifying ICE_ITR_NONE, which will vary in adaptive (AIM) mode and
         * be static in non-adaptive mode (user configured)
         */
        wr32(&vsi->back->hw, GLINT_DYN_CTL(q_vector->reg_idx),
             ((ICE_ITR_NONE << GLINT_DYN_CTL_ITR_INDX_S) &
              GLINT_DYN_CTL_ITR_INDX_M) | GLINT_DYN_CTL_INTENA_MSK_M |
             GLINT_DYN_CTL_WB_ON_ITR_M);

        q_vector->wb_on_itr = true;
}

/**
 * ice_napi_poll - NAPI polling Rx/Tx cleanup routine
 * @napi: napi struct with our devices info in it
 * @budget: amount of work driver is allowed to do this pass, in packets
 *
 * This function will clean all queues associated with a q_vector.
 *
 * Returns the amount of work done
 */
int ice_napi_poll(struct napi_struct *napi, int budget)
{
        struct ice_q_vector *q_vector =
                                container_of(napi, struct ice_q_vector, napi);
        struct ice_tx_ring *tx_ring;
        struct ice_rx_ring *rx_ring;
        bool clean_complete = true;
        int budget_per_ring;
        int work_done = 0;

        /* Since the actual Tx work is minimal, we can give the Tx a larger
         * budget and be more aggressive about cleaning up the Tx descriptors.
         */
        ice_for_each_tx_ring(tx_ring, q_vector->tx) {
                bool wd;

                if (tx_ring->xsk_pool)
                        wd = ice_xmit_zc(tx_ring, ICE_DESC_UNUSED(tx_ring), budget);
                else if (ice_ring_is_xdp(tx_ring))
                        wd = true;
                else
                        wd = ice_clean_tx_irq(tx_ring, budget);

                if (!wd)
                        clean_complete = false;
        }

        /* Handle case where we are called by netpoll with a budget of 0 */
        if (unlikely(budget <= 0))
                return budget;

        /* normally we have 1 Rx ring per q_vector */
        if (unlikely(q_vector->num_ring_rx > 1))
                /* We attempt to distribute budget to each Rx queue fairly, but
                 * don't allow the budget to go below 1 because that would exit
                 * polling early.
                 */
                budget_per_ring = max_t(int, budget / q_vector->num_ring_rx, 1);
        else
                /* Max of 1 Rx ring in this q_vector so give it the budget */
                budget_per_ring = budget;

        ice_for_each_rx_ring(rx_ring, q_vector->rx) {
                int cleaned;

                /* A dedicated path for zero-copy allows making a single
                 * comparison in the irq context instead of many inside the
                 * ice_clean_rx_irq function and makes the codebase cleaner.
                 */
                cleaned = rx_ring->xsk_pool ?
                          ice_clean_rx_irq_zc(rx_ring, budget_per_ring) :
                          ice_clean_rx_irq(rx_ring, budget_per_ring);
                work_done += cleaned;
                /* if we clean as many as budgeted, we must not be done */
                if (cleaned >= budget_per_ring)
                        clean_complete = false;
        }

        /* If work not completed, return budget and polling will return */
        if (!clean_complete) {
                /* Set the writeback on ITR so partial completions of
                 * cache-lines will still continue even if we're polling.
                 */
                ice_set_wb_on_itr(q_vector);
                return budget;
        }

        /* Exit the polling mode, but don't re-enable interrupts if stack might
         * poll us due to busy-polling
         */
        if (napi_complete_done(napi, work_done)) {
                ice_net_dim(q_vector);
                ice_enable_interrupt(q_vector);
        } else {
                ice_set_wb_on_itr(q_vector);
        }

        return min_t(int, work_done, budget - 1);
}

/**
 * __ice_maybe_stop_tx - 2nd level check for Tx stop conditions
 * @tx_ring: the ring to be checked
 * @size: the size buffer we want to assure is available
 *
 * Returns -EBUSY if a stop is needed, else 0
 */
static int __ice_maybe_stop_tx(struct ice_tx_ring *tx_ring, unsigned int size)
{
        netif_tx_stop_queue(txring_txq(tx_ring));
        /* Memory barrier before checking head and tail */
        smp_mb();

        /* Check again in a case another CPU has just made room available. */
        if (likely(ICE_DESC_UNUSED(tx_ring) < size))
                return -EBUSY;

        /* A reprieve! - use start_queue because it doesn't call schedule */
        netif_tx_start_queue(txring_txq(tx_ring));
        ++tx_ring->tx_stats.restart_q;
        return 0;
}

/**
 * ice_maybe_stop_tx - 1st level check for Tx stop conditions
 * @tx_ring: the ring to be checked
 * @size:    the size buffer we want to assure is available
 *
 * Returns 0 if stop is not needed
 */
static int ice_maybe_stop_tx(struct ice_tx_ring *tx_ring, unsigned int size)
{
        if (likely(ICE_DESC_UNUSED(tx_ring) >= size))
                return 0;

        return __ice_maybe_stop_tx(tx_ring, size);
}

/**
 * ice_tx_map - Build the Tx descriptor
 * @tx_ring: ring to send buffer on
 * @first: first buffer info buffer to use
 * @off: pointer to struct that holds offload parameters
 *
 * This function loops over the skb data pointed to by *first
 * and gets a physical address for each memory location and programs
 * it and the length into the transmit descriptor.
 */
static void
ice_tx_map(struct ice_tx_ring *tx_ring, struct ice_tx_buf *first,
           struct ice_tx_offload_params *off)
{
        u64 td_offset, td_tag, td_cmd;
        u16 i = tx_ring->next_to_use;
        unsigned int data_len, size;
        struct ice_tx_desc *tx_desc;
        struct ice_tx_buf *tx_buf;
        struct sk_buff *skb;
        skb_frag_t *frag;
        dma_addr_t dma;
        bool kick;

        td_tag = off->td_l2tag1;
        td_cmd = off->td_cmd;
        td_offset = off->td_offset;
        skb = first->skb;

        data_len = skb->data_len;
        size = skb_headlen(skb);

        tx_desc = ICE_TX_DESC(tx_ring, i);

        if (first->tx_flags & ICE_TX_FLAGS_HW_VLAN) {
                td_cmd |= (u64)ICE_TX_DESC_CMD_IL2TAG1;
                td_tag = (first->tx_flags & ICE_TX_FLAGS_VLAN_M) >>
                          ICE_TX_FLAGS_VLAN_S;
        }

        dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);

        tx_buf = first;

        for (frag = &skb_shinfo(skb)->frags[0];; frag++) {
                unsigned int max_data = ICE_MAX_DATA_PER_TXD_ALIGNED;

                if (dma_mapping_error(tx_ring->dev, dma))
                        goto dma_error;

                /* record length, and DMA address */
                dma_unmap_len_set(tx_buf, len, size);
                dma_unmap_addr_set(tx_buf, dma, dma);

                /* align size to end of page */
                max_data += -dma & (ICE_MAX_READ_REQ_SIZE - 1);
                tx_desc->buf_addr = cpu_to_le64(dma);

                /* account for data chunks larger than the hardware
                 * can handle
                 */
                while (unlikely(size > ICE_MAX_DATA_PER_TXD)) {
                        tx_desc->cmd_type_offset_bsz =
                                ice_build_ctob(td_cmd, td_offset, max_data,
                                               td_tag);

                        tx_desc++;
                        i++;

                        if (i == tx_ring->count) {
                                tx_desc = ICE_TX_DESC(tx_ring, 0);
                                i = 0;
                        }

                        dma += max_data;
                        size -= max_data;

                        max_data = ICE_MAX_DATA_PER_TXD_ALIGNED;
                        tx_desc->buf_addr = cpu_to_le64(dma);
                }

                if (likely(!data_len))
                        break;

                tx_desc->cmd_type_offset_bsz = ice_build_ctob(td_cmd, td_offset,
                                                              size, td_tag);

                tx_desc++;
                i++;

                if (i == tx_ring->count) {
                        tx_desc = ICE_TX_DESC(tx_ring, 0);
                        i = 0;
                }

                size = skb_frag_size(frag);
                data_len -= size;

                dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size,
                                       DMA_TO_DEVICE);

                tx_buf = &tx_ring->tx_buf[i];
        }

        /* record SW timestamp if HW timestamp is not available */
        skb_tx_timestamp(first->skb);

        i++;
        if (i == tx_ring->count)
                i = 0;

        /* write last descriptor with RS and EOP bits */
        td_cmd |= (u64)ICE_TXD_LAST_DESC_CMD;
        tx_desc->cmd_type_offset_bsz =
                        ice_build_ctob(td_cmd, td_offset, size, td_tag);

        /* Force memory writes to complete before letting h/w know there
         * are new descriptors to fetch.
         *
         * We also use this memory barrier to make certain all of the
         * status bits have been updated before next_to_watch is written.
         */
        wmb();

        /* set next_to_watch value indicating a packet is present */
        first->next_to_watch = tx_desc;

        tx_ring->next_to_use = i;

        ice_maybe_stop_tx(tx_ring, DESC_NEEDED);

        /* notify HW of packet */
        kick = __netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount,
                                      netdev_xmit_more());
        if (kick)
                /* notify HW of packet */
                writel(i, tx_ring->tail);

        return;

dma_error:
        /* clear DMA mappings for failed tx_buf map */
        for (;;) {
                tx_buf = &tx_ring->tx_buf[i];
                ice_unmap_and_free_tx_buf(tx_ring, tx_buf);
                if (tx_buf == first)
                        break;
                if (i == 0)
                        i = tx_ring->count;
                i--;
        }

        tx_ring->next_to_use = i;
}

/**
 * ice_tx_csum - Enable Tx checksum offloads
 * @first: pointer to the first descriptor
 * @off: pointer to struct that holds offload parameters
 *
 * Returns 0 or error (negative) if checksum offload can't happen, 1 otherwise.
 */
static
int ice_tx_csum(struct ice_tx_buf *first, struct ice_tx_offload_params *off)
{
        u32 l4_len = 0, l3_len = 0, l2_len = 0;
        struct sk_buff *skb = first->skb;
        union {
                struct iphdr *v4;
                struct ipv6hdr *v6;
                unsigned char *hdr;
        } ip;
        union {
                struct tcphdr *tcp;
                unsigned char *hdr;
        } l4;
        __be16 frag_off, protocol;
        unsigned char *exthdr;
        u32 offset, cmd = 0;
        u8 l4_proto = 0;

        if (skb->ip_summed != CHECKSUM_PARTIAL)
                return 0;

        protocol = vlan_get_protocol(skb);

        if (eth_p_mpls(protocol)) {
                ip.hdr = skb_inner_network_header(skb);
                l4.hdr = skb_checksum_start(skb);
        } else {
                ip.hdr = skb_network_header(skb);
                l4.hdr = skb_transport_header(skb);
        }

        /* compute outer L2 header size */
        l2_len = ip.hdr - skb->data;
        offset = (l2_len / 2) << ICE_TX_DESC_LEN_MACLEN_S;

        /* set the tx_flags to indicate the IP protocol type. this is
         * required so that checksum header computation below is accurate.
         */
        if (ip.v4->version == 4)
                first->tx_flags |= ICE_TX_FLAGS_IPV4;
        else if (ip.v6->version == 6)
                first->tx_flags |= ICE_TX_FLAGS_IPV6;

        if (skb->encapsulation) {
                bool gso_ena = false;
                u32 tunnel = 0;

                /* define outer network header type */
                if (first->tx_flags & ICE_TX_FLAGS_IPV4) {
                        tunnel |= (first->tx_flags & ICE_TX_FLAGS_TSO) ?
                                  ICE_TX_CTX_EIPT_IPV4 :
                                  ICE_TX_CTX_EIPT_IPV4_NO_CSUM;
                        l4_proto = ip.v4->protocol;
                } else if (first->tx_flags & ICE_TX_FLAGS_IPV6) {
                        int ret;

                        tunnel |= ICE_TX_CTX_EIPT_IPV6;
                        exthdr = ip.hdr + sizeof(*ip.v6);
                        l4_proto = ip.v6->nexthdr;
                        ret = ipv6_skip_exthdr(skb, exthdr - skb->data,
                                               &l4_proto, &frag_off);
                        if (ret < 0)
                                return -1;
                }

                /* define outer transport */
                switch (l4_proto) {
                case IPPROTO_UDP:
                        tunnel |= ICE_TXD_CTX_UDP_TUNNELING;
                        first->tx_flags |= ICE_TX_FLAGS_TUNNEL;
                        break;
                case IPPROTO_GRE:
                        tunnel |= ICE_TXD_CTX_GRE_TUNNELING;
                        first->tx_flags |= ICE_TX_FLAGS_TUNNEL;
                        break;
                case IPPROTO_IPIP:
                case IPPROTO_IPV6:
                        first->tx_flags |= ICE_TX_FLAGS_TUNNEL;
                        l4.hdr = skb_inner_network_header(skb);
                        break;
                default:
                        if (first->tx_flags & ICE_TX_FLAGS_TSO)
                                return -1;

                        skb_checksum_help(skb);
                        return 0;
                }

                /* compute outer L3 header size */
                tunnel |= ((l4.hdr - ip.hdr) / 4) <<
                          ICE_TXD_CTX_QW0_EIPLEN_S;

                /* switch IP header pointer from outer to inner header */
                ip.hdr = skb_inner_network_header(skb);

                /* compute tunnel header size */
                tunnel |= ((ip.hdr - l4.hdr) / 2) <<
                           ICE_TXD_CTX_QW0_NATLEN_S;

                gso_ena = skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL;
                /* indicate if we need to offload outer UDP header */
                if ((first->tx_flags & ICE_TX_FLAGS_TSO) && !gso_ena &&
                    (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM))
                        tunnel |= ICE_TXD_CTX_QW0_L4T_CS_M;

                /* record tunnel offload values */
                off->cd_tunnel_params |= tunnel;

                /* set DTYP=1 to indicate that it's an Tx context descriptor
                 * in IPsec tunnel mode with Tx offloads in Quad word 1
                 */
                off->cd_qw1 |= (u64)ICE_TX_DESC_DTYPE_CTX;

                /* switch L4 header pointer from outer to inner */
                l4.hdr = skb_inner_transport_header(skb);
                l4_proto = 0;

                /* reset type as we transition from outer to inner headers */
                first->tx_flags &= ~(ICE_TX_FLAGS_IPV4 | ICE_TX_FLAGS_IPV6);
                if (ip.v4->version == 4)
                        first->tx_flags |= ICE_TX_FLAGS_IPV4;
                if (ip.v6->version == 6)
                        first->tx_flags |= ICE_TX_FLAGS_IPV6;
        }

        /* Enable IP checksum offloads */
        if (first->tx_flags & ICE_TX_FLAGS_IPV4) {
                l4_proto = ip.v4->protocol;
                /* the stack computes the IP header already, the only time we
                 * need the hardware to recompute it is in the case of TSO.
                 */
                if (first->tx_flags & ICE_TX_FLAGS_TSO)
                        cmd |= ICE_TX_DESC_CMD_IIPT_IPV4_CSUM;
                else
                        cmd |= ICE_TX_DESC_CMD_IIPT_IPV4;

        } else if (first->tx_flags & ICE_TX_FLAGS_IPV6) {
                cmd |= ICE_TX_DESC_CMD_IIPT_IPV6;
                exthdr = ip.hdr + sizeof(*ip.v6);
                l4_proto = ip.v6->nexthdr;
                if (l4.hdr != exthdr)
                        ipv6_skip_exthdr(skb, exthdr - skb->data, &l4_proto,
                                         &frag_off);
        } else {
                return -1;
        }

        /* compute inner L3 header size */
        l3_len = l4.hdr - ip.hdr;
        offset |= (l3_len / 4) << ICE_TX_DESC_LEN_IPLEN_S;

        /* Enable L4 checksum offloads */
        switch (l4_proto) {
        case IPPROTO_TCP:
                /* enable checksum offloads */
                cmd |= ICE_TX_DESC_CMD_L4T_EOFT_TCP;
                l4_len = l4.tcp->doff;
                offset |= l4_len << ICE_TX_DESC_LEN_L4_LEN_S;
                break;
        case IPPROTO_UDP:
                /* enable UDP checksum offload */
                cmd |= ICE_TX_DESC_CMD_L4T_EOFT_UDP;
                l4_len = (sizeof(struct udphdr) >> 2);
                offset |= l4_len << ICE_TX_DESC_LEN_L4_LEN_S;
                break;
        case IPPROTO_SCTP:
                /* enable SCTP checksum offload */
                cmd |= ICE_TX_DESC_CMD_L4T_EOFT_SCTP;
                l4_len = sizeof(struct sctphdr) >> 2;
                offset |= l4_len << ICE_TX_DESC_LEN_L4_LEN_S;
                break;

        default:
                if (first->tx_flags & ICE_TX_FLAGS_TSO)
                        return -1;
                skb_checksum_help(skb);
                return 0;
        }

        off->td_cmd |= cmd;
        off->td_offset |= offset;
        return 1;
}

/**
 * ice_tx_prepare_vlan_flags - prepare generic Tx VLAN tagging flags for HW
 * @tx_ring: ring to send buffer on
 * @first: pointer to struct ice_tx_buf
 *
 * Checks the skb and set up correspondingly several generic transmit flags
 * related to VLAN tagging for the HW, such as VLAN, DCB, etc.
 */
static void
ice_tx_prepare_vlan_flags(struct ice_tx_ring *tx_ring, struct ice_tx_buf *first)
{
        struct sk_buff *skb = first->skb;

        /* nothing left to do, software offloaded VLAN */
        if (!skb_vlan_tag_present(skb) && eth_type_vlan(skb->protocol))
                return;

        /* the VLAN ethertype/tpid is determined by VSI configuration and netdev
         * feature flags, which the driver only allows either 802.1Q or 802.1ad
         * VLAN offloads exclusively so we only care about the VLAN ID here
         */
        if (skb_vlan_tag_present(skb)) {
                first->tx_flags |= skb_vlan_tag_get(skb) << ICE_TX_FLAGS_VLAN_S;
                if (tx_ring->flags & ICE_TX_FLAGS_RING_VLAN_L2TAG2)
                        first->tx_flags |= ICE_TX_FLAGS_HW_OUTER_SINGLE_VLAN;
                else
                        first->tx_flags |= ICE_TX_FLAGS_HW_VLAN;
        }

        ice_tx_prepare_vlan_flags_dcb(tx_ring, first);
}

/**
 * ice_tso - computes mss and TSO length to prepare for TSO
 * @first: pointer to struct ice_tx_buf
 * @off: pointer to struct that holds offload parameters
 *
 * Returns 0 or error (negative) if TSO can't happen, 1 otherwise.
 */
static
int ice_tso(struct ice_tx_buf *first, struct ice_tx_offload_params *off)
{
        struct sk_buff *skb = first->skb;
        union {
                struct iphdr *v4;
                struct ipv6hdr *v6;
                unsigned char *hdr;
        } ip;
        union {
                struct tcphdr *tcp;
                struct udphdr *udp;
                unsigned char *hdr;
        } l4;
        u64 cd_mss, cd_tso_len;
        __be16 protocol;
        u32 paylen;
        u8 l4_start;
        int err;

        if (skb->ip_summed != CHECKSUM_PARTIAL)
                return 0;

        if (!skb_is_gso(skb))
                return 0;

        err = skb_cow_head(skb, 0);
        if (err < 0)
                return err;

        /* cppcheck-suppress unreadVariable */
        protocol = vlan_get_protocol(skb);

        if (eth_p_mpls(protocol))
                ip.hdr = skb_inner_network_header(skb);
        else
                ip.hdr = skb_network_header(skb);
        l4.hdr = skb_checksum_start(skb);

        /* initialize outer IP header fields */
        if (ip.v4->version == 4) {
                ip.v4->tot_len = 0;
                ip.v4->check = 0;
        } else {
                ip.v6->payload_len = 0;
        }

        if (skb_shinfo(skb)->gso_type & (SKB_GSO_GRE |
                                         SKB_GSO_GRE_CSUM |
                                         SKB_GSO_IPXIP4 |
                                         SKB_GSO_IPXIP6 |
                                         SKB_GSO_UDP_TUNNEL |
                                         SKB_GSO_UDP_TUNNEL_CSUM)) {
                if (!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
                    (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)) {
                        l4.udp->len = 0;

                        /* determine offset of outer transport header */
                        l4_start = (u8)(l4.hdr - skb->data);

                        /* remove payload length from outer checksum */
                        paylen = skb->len - l4_start;
                        csum_replace_by_diff(&l4.udp->check,
                                             (__force __wsum)htonl(paylen));
                }

                /* reset pointers to inner headers */

                /* cppcheck-suppress unreadVariable */
                ip.hdr = skb_inner_network_header(skb);
                l4.hdr = skb_inner_transport_header(skb);

                /* initialize inner IP header fields */
                if (ip.v4->version == 4) {
                        ip.v4->tot_len = 0;
                        ip.v4->check = 0;
                } else {
                        ip.v6->payload_len = 0;
                }
        }

        /* determine offset of transport header */
        l4_start = (u8)(l4.hdr - skb->data);

        /* remove payload length from checksum */
        paylen = skb->len - l4_start;

        if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
                csum_replace_by_diff(&l4.udp->check,
                                     (__force __wsum)htonl(paylen));
                /* compute length of UDP segmentation header */
                off->header_len = (u8)sizeof(l4.udp) + l4_start;
        } else {
                csum_replace_by_diff(&l4.tcp->check,
                                     (__force __wsum)htonl(paylen));
                /* compute length of TCP segmentation header */
                off->header_len = (u8)((l4.tcp->doff * 4) + l4_start);
        }

        /* update gso_segs and bytecount */
        first->gso_segs = skb_shinfo(skb)->gso_segs;
        first->bytecount += (first->gso_segs - 1) * off->header_len;

        cd_tso_len = skb->len - off->header_len;
        cd_mss = skb_shinfo(skb)->gso_size;

        /* record cdesc_qw1 with TSO parameters */
        off->cd_qw1 |= (u64)(ICE_TX_DESC_DTYPE_CTX |
                             (ICE_TX_CTX_DESC_TSO << ICE_TXD_CTX_QW1_CMD_S) |
                             (cd_tso_len << ICE_TXD_CTX_QW1_TSO_LEN_S) |
                             (cd_mss << ICE_TXD_CTX_QW1_MSS_S));
        first->tx_flags |= ICE_TX_FLAGS_TSO;
        return 1;
}

/**
 * ice_txd_use_count  - estimate the number of descriptors needed for Tx
 * @size: transmit request size in bytes
 *
 * Due to hardware alignment restrictions (4K alignment), we need to
 * assume that we can have no more than 12K of data per descriptor, even
 * though each descriptor can take up to 16K - 1 bytes of aligned memory.
 * Thus, we need to divide by 12K. But division is slow! Instead,
 * we decompose the operation into shifts and one relatively cheap
 * multiply operation.
 *
 * To divide by 12K, we first divide by 4K, then divide by 3:
 *     To divide by 4K, shift right by 12 bits
 *     To divide by 3, multiply by 85, then divide by 256
 *     (Divide by 256 is done by shifting right by 8 bits)
 * Finally, we add one to round up. Because 256 isn't an exact multiple of
 * 3, we'll underestimate near each multiple of 12K. This is actually more
 * accurate as we have 4K - 1 of wiggle room that we can fit into the last
 * segment. For our purposes this is accurate out to 1M which is orders of
 * magnitude greater than our largest possible GSO size.
 *
 * This would then be implemented as:
 *     return (((size >> 12) * 85) >> 8) + ICE_DESCS_FOR_SKB_DATA_PTR;
 *
 * Since multiplication and division are commutative, we can reorder
 * operations into:
 *     return ((size * 85) >> 20) + ICE_DESCS_FOR_SKB_DATA_PTR;
 */
static unsigned int ice_txd_use_count(unsigned int size)
{
        return ((size * 85) >> 20) + ICE_DESCS_FOR_SKB_DATA_PTR;
}

/**
 * ice_xmit_desc_count - calculate number of Tx descriptors needed
 * @skb: send buffer
 *
 * Returns number of data descriptors needed for this skb.
 */
static unsigned int ice_xmit_desc_count(struct sk_buff *skb)
{
        const skb_frag_t *frag = &skb_shinfo(skb)->frags[0];
        unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
        unsigned int count = 0, size = skb_headlen(skb);

        for (;;) {
                count += ice_txd_use_count(size);

                if (!nr_frags--)
                        break;

                size = skb_frag_size(frag++);
        }

        return count;
}

/**
 * __ice_chk_linearize - Check if there are more than 8 buffers per packet
 * @skb: send buffer
 *
 * Note: This HW can't DMA more than 8 buffers to build a packet on the wire
 * and so we need to figure out the cases where we need to linearize the skb.
 *
 * For TSO we need to count the TSO header and segment payload separately.
 * As such we need to check cases where we have 7 fragments or more as we
 * can potentially require 9 DMA transactions, 1 for the TSO header, 1 for
 * the segment payload in the first descriptor, and another 7 for the
 * fragments.
 */
static bool __ice_chk_linearize(struct sk_buff *skb)
{
        const skb_frag_t *frag, *stale;
        int nr_frags, sum;

        /* no need to check if number of frags is less than 7 */
        nr_frags = skb_shinfo(skb)->nr_frags;
        if (nr_frags < (ICE_MAX_BUF_TXD - 1))
                return false;

        /* We need to walk through the list and validate that each group
         * of 6 fragments totals at least gso_size.
         */
        nr_frags -= ICE_MAX_BUF_TXD - 2;
        frag = &skb_shinfo(skb)->frags[0];

        /* Initialize size to the negative value of gso_size minus 1. We
         * use this as the worst case scenario in which the frag ahead
         * of us only provides one byte which is why we are limited to 6
         * descriptors for a single transmit as the header and previous
         * fragment are already consuming 2 descriptors.
         */
        sum = 1 - skb_shinfo(skb)->gso_size;

        /* Add size of frags 0 through 4 to create our initial sum */
        sum += skb_frag_size(frag++);
        sum += skb_frag_size(frag++);
        sum += skb_frag_size(frag++);
        sum += skb_frag_size(frag++);
        sum += skb_frag_size(frag++);

        /* Walk through fragments adding latest fragment, testing it, and
         * then removing stale fragments from the sum.
         */
        for (stale = &skb_shinfo(skb)->frags[0];; stale++) {
                int stale_size = skb_frag_size(stale);

                sum += skb_frag_size(frag++);

                /* The stale fragment may present us with a smaller
                 * descriptor than the actual fragment size. To account
                 * for that we need to remove all the data on the front and
                 * figure out what the remainder would be in the last
                 * descriptor associated with the fragment.
                 */
                if (stale_size > ICE_MAX_DATA_PER_TXD) {
                        int align_pad = -(skb_frag_off(stale)) &
                                        (ICE_MAX_READ_REQ_SIZE - 1);

                        sum -= align_pad;
                        stale_size -= align_pad;

                        do {
                                sum -= ICE_MAX_DATA_PER_TXD_ALIGNED;
                                stale_size -= ICE_MAX_DATA_PER_TXD_ALIGNED;
                        } while (stale_size > ICE_MAX_DATA_PER_TXD);
                }

                /* if sum is negative we failed to make sufficient progress */
                if (sum < 0)
                        return true;

                if (!nr_frags--)
                        break;

                sum -= stale_size;
        }

        return false;
}

/**
 * ice_chk_linearize - Check if there are more than 8 fragments per packet
 * @skb:      send buffer
 * @count:    number of buffers used
 *
 * Note: Our HW can't scatter-gather more than 8 fragments to build
 * a packet on the wire and so we need to figure out the cases where we
 * need to linearize the skb.
 */
static bool ice_chk_linearize(struct sk_buff *skb, unsigned int count)
{
        /* Both TSO and single send will work if count is less than 8 */
        if (likely(count < ICE_MAX_BUF_TXD))
                return false;

        if (skb_is_gso(skb))
                return __ice_chk_linearize(skb);

        /* we can support up to 8 data buffers for a single send */
        return count != ICE_MAX_BUF_TXD;
}

/**
 * ice_tstamp - set up context descriptor for hardware timestamp
 * @tx_ring: pointer to the Tx ring to send buffer on
 * @skb: pointer to the SKB we're sending
 * @first: Tx buffer
 * @off: Tx offload parameters
 */
static void
ice_tstamp(struct ice_tx_ring *tx_ring, struct sk_buff *skb,
           struct ice_tx_buf *first, struct ice_tx_offload_params *off)
{
        s8 idx;

        /* only timestamp the outbound packet if the user has requested it */
        if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)))
                return;

        if (!tx_ring->ptp_tx)
                return;

        /* Tx timestamps cannot be sampled when doing TSO */
        if (first->tx_flags & ICE_TX_FLAGS_TSO)
                return;

        /* Grab an open timestamp slot */
        idx = ice_ptp_request_ts(tx_ring->tx_tstamps, skb);
        if (idx < 0)
                return;

        off->cd_qw1 |= (u64)(ICE_TX_DESC_DTYPE_CTX |
                             (ICE_TX_CTX_DESC_TSYN << ICE_TXD_CTX_QW1_CMD_S) |
                             ((u64)idx << ICE_TXD_CTX_QW1_TSO_LEN_S));
        first->tx_flags |= ICE_TX_FLAGS_TSYN;
}

/**
 * ice_xmit_frame_ring - Sends buffer on Tx ring
 * @skb: send buffer
 * @tx_ring: ring to send buffer on
 *
 * Returns NETDEV_TX_OK if sent, else an error code
 */
static netdev_tx_t
ice_xmit_frame_ring(struct sk_buff *skb, struct ice_tx_ring *tx_ring)
{
        struct ice_tx_offload_params offload = { 0 };
        struct ice_vsi *vsi = tx_ring->vsi;
        struct ice_tx_buf *first;
        struct ethhdr *eth;
        unsigned int count;
        int tso, csum;

        ice_trace(xmit_frame_ring, tx_ring, skb);

        count = ice_xmit_desc_count(skb);
        if (ice_chk_linearize(skb, count)) {
                if (__skb_linearize(skb))
                        goto out_drop;
                count = ice_txd_use_count(skb->len);
                tx_ring->tx_stats.tx_linearize++;
        }

        /* need: 1 descriptor per page * PAGE_SIZE/ICE_MAX_DATA_PER_TXD,
         *       + 1 desc for skb_head_len/ICE_MAX_DATA_PER_TXD,
         *       + 4 desc gap to avoid the cache line where head is,
         *       + 1 desc for context descriptor,
         * otherwise try next time
         */
        if (ice_maybe_stop_tx(tx_ring, count + ICE_DESCS_PER_CACHE_LINE +
                              ICE_DESCS_FOR_CTX_DESC)) {
                tx_ring->tx_stats.tx_busy++;
                return NETDEV_TX_BUSY;
        }

        /* prefetch for bql data which is infrequently used */
        netdev_txq_bql_enqueue_prefetchw(txring_txq(tx_ring));

        offload.tx_ring = tx_ring;

        /* record the location of the first descriptor for this packet */
        first = &tx_ring->tx_buf[tx_ring->next_to_use];
        first->skb = skb;
        first->bytecount = max_t(unsigned int, skb->len, ETH_ZLEN);
        first->gso_segs = 1;
        first->tx_flags = 0;

        /* prepare the VLAN tagging flags for Tx */
        ice_tx_prepare_vlan_flags(tx_ring, first);
        if (first->tx_flags & ICE_TX_FLAGS_HW_OUTER_SINGLE_VLAN) {
                offload.cd_qw1 |= (u64)(ICE_TX_DESC_DTYPE_CTX |
                                        (ICE_TX_CTX_DESC_IL2TAG2 <<
                                        ICE_TXD_CTX_QW1_CMD_S));
                offload.cd_l2tag2 = (first->tx_flags & ICE_TX_FLAGS_VLAN_M) >>
                        ICE_TX_FLAGS_VLAN_S;
        }

        /* set up TSO offload */
        tso = ice_tso(first, &offload);
        if (tso < 0)
                goto out_drop;

        /* always set up Tx checksum offload */
        csum = ice_tx_csum(first, &offload);
        if (csum < 0)
                goto out_drop;

        /* allow CONTROL frames egress from main VSI if FW LLDP disabled */
        eth = (struct ethhdr *)skb_mac_header(skb);
        if (unlikely((skb->priority == TC_PRIO_CONTROL ||
                      eth->h_proto == htons(ETH_P_LLDP)) &&
                     vsi->type == ICE_VSI_PF &&
                     vsi->port_info->qos_cfg.is_sw_lldp))
                offload.cd_qw1 |= (u64)(ICE_TX_DESC_DTYPE_CTX |
                                        ICE_TX_CTX_DESC_SWTCH_UPLINK <<
                                        ICE_TXD_CTX_QW1_CMD_S);

        ice_tstamp(tx_ring, skb, first, &offload);
        if (ice_is_switchdev_running(vsi->back))
                ice_eswitch_set_target_vsi(skb, &offload);

        if (offload.cd_qw1 & ICE_TX_DESC_DTYPE_CTX) {
                struct ice_tx_ctx_desc *cdesc;
                u16 i = tx_ring->next_to_use;

                /* grab the next descriptor */
                cdesc = ICE_TX_CTX_DESC(tx_ring, i);
                i++;
                tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;

                /* setup context descriptor */
                cdesc->tunneling_params = cpu_to_le32(offload.cd_tunnel_params);
                cdesc->l2tag2 = cpu_to_le16(offload.cd_l2tag2);
                cdesc->rsvd = cpu_to_le16(0);
                cdesc->qw1 = cpu_to_le64(offload.cd_qw1);
        }

        ice_tx_map(tx_ring, first, &offload);
        return NETDEV_TX_OK;

out_drop:
        ice_trace(xmit_frame_ring_drop, tx_ring, skb);
        dev_kfree_skb_any(skb);
        return NETDEV_TX_OK;
}

/**
 * ice_start_xmit - Selects the correct VSI and Tx queue to send buffer
 * @skb: send buffer
 * @netdev: network interface device structure
 *
 * Returns NETDEV_TX_OK if sent, else an error code
 */
netdev_tx_t ice_start_xmit(struct sk_buff *skb, struct net_device *netdev)
{
        struct ice_netdev_priv *np = netdev_priv(netdev);
        struct ice_vsi *vsi = np->vsi;
        struct ice_tx_ring *tx_ring;

        tx_ring = vsi->tx_rings[skb->queue_mapping];

        /* hardware can't handle really short frames, hardware padding works
         * beyond this point
         */
        if (skb_put_padto(skb, ICE_MIN_TX_LEN))
                return NETDEV_TX_OK;

        return ice_xmit_frame_ring(skb, tx_ring);
}

/**
 * ice_get_dscp_up - return the UP/TC value for a SKB
 * @dcbcfg: DCB config that contains DSCP to UP/TC mapping
 * @skb: SKB to query for info to determine UP/TC
 *
 * This function is to only be called when the PF is in L3 DSCP PFC mode
 */
static u8 ice_get_dscp_up(struct ice_dcbx_cfg *dcbcfg, struct sk_buff *skb)
{
        u8 dscp = 0;

        if (skb->protocol == htons(ETH_P_IP))
                dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
        else if (skb->protocol == htons(ETH_P_IPV6))
                dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;

        return dcbcfg->dscp_map[dscp];
}

u16
ice_select_queue(struct net_device *netdev, struct sk_buff *skb,
                 struct net_device *sb_dev)
{
        struct ice_pf *pf = ice_netdev_to_pf(netdev);
        struct ice_dcbx_cfg *dcbcfg;

        dcbcfg = &pf->hw.port_info->qos_cfg.local_dcbx_cfg;
        if (dcbcfg->pfc_mode == ICE_QOS_MODE_DSCP)
                skb->priority = ice_get_dscp_up(dcbcfg, skb);

        return netdev_pick_tx(netdev, skb, sb_dev);
}

/**
 * ice_clean_ctrl_tx_irq - interrupt handler for flow director Tx queue
 * @tx_ring: tx_ring to clean
 */
void ice_clean_ctrl_tx_irq(struct ice_tx_ring *tx_ring)
{
        struct ice_vsi *vsi = tx_ring->vsi;
        s16 i = tx_ring->next_to_clean;
        int budget = ICE_DFLT_IRQ_WORK;
        struct ice_tx_desc *tx_desc;
        struct ice_tx_buf *tx_buf;

        tx_buf = &tx_ring->tx_buf[i];
        tx_desc = ICE_TX_DESC(tx_ring, i);
        i -= tx_ring->count;

        do {
                struct ice_tx_desc *eop_desc = tx_buf->next_to_watch;

                /* if next_to_watch is not set then there is no pending work */
                if (!eop_desc)
                        break;

                /* prevent any other reads prior to eop_desc */
                smp_rmb();

                /* if the descriptor isn't done, no work to do */
                if (!(eop_desc->cmd_type_offset_bsz &
                      cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE)))
                        break;

                /* clear next_to_watch to prevent false hangs */
                tx_buf->next_to_watch = NULL;
                tx_desc->buf_addr = 0;
                tx_desc->cmd_type_offset_bsz = 0;

                /* move past filter desc */
                tx_buf++;
                tx_desc++;
                i++;
                if (unlikely(!i)) {
                        i -= tx_ring->count;
                        tx_buf = tx_ring->tx_buf;
                        tx_desc = ICE_TX_DESC(tx_ring, 0);
                }

                /* unmap the data header */
                if (dma_unmap_len(tx_buf, len))
                        dma_unmap_single(tx_ring->dev,
                                         dma_unmap_addr(tx_buf, dma),
                                         dma_unmap_len(tx_buf, len),
                                         DMA_TO_DEVICE);
                if (tx_buf->tx_flags & ICE_TX_FLAGS_DUMMY_PKT)
                        devm_kfree(tx_ring->dev, tx_buf->raw_buf);

                /* clear next_to_watch to prevent false hangs */
                tx_buf->raw_buf = NULL;
                tx_buf->tx_flags = 0;
                tx_buf->next_to_watch = NULL;
                dma_unmap_len_set(tx_buf, len, 0);
                tx_desc->buf_addr = 0;
                tx_desc->cmd_type_offset_bsz = 0;

                /* move past eop_desc for start of next FD desc */
                tx_buf++;
                tx_desc++;
                i++;
                if (unlikely(!i)) {
                        i -= tx_ring->count;
                        tx_buf = tx_ring->tx_buf;
                        tx_desc = ICE_TX_DESC(tx_ring, 0);
                }

                budget--;
        } while (likely(budget));

        i += tx_ring->count;
        tx_ring->next_to_clean = i;

        /* re-enable interrupt if needed */
        ice_irq_dynamic_ena(&vsi->back->hw, vsi, vsi->q_vectors[0]);
}