Merge tag 'pwm/for-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry...

[mirror_ubuntu-hirsute-kernel.git] / drivers / net / ethernet / intel / i40e / i40e_txrx.h

/* SPDX-License-Identifier: GPL-2.0 */
/*******************************************************************************
 *
 * Intel Ethernet Controller XL710 Family Linux Driver
 * Copyright(c) 2013 - 2016 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Contact Information:
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 ******************************************************************************/

#ifndef _I40E_TXRX_H_
#define _I40E_TXRX_H_

#include <net/xdp.h>

/* Interrupt Throttling and Rate Limiting Goodies */
#define I40E_DEFAULT_IRQ_WORK      256

/* The datasheet for the X710 and XL710 indicate that the maximum value for
 * the ITR is 8160usec which is then called out as 0xFF0 with a 2usec
 * resolution. 8160 is 0x1FE0 when written out in hex. So instead of storing
 * the register value which is divided by 2 lets use the actual values and
 * avoid an excessive amount of translation.
 */
#define I40E_ITR_DYNAMIC        0x8000  /* use top bit as a flag */
#define I40E_ITR_MASK           0x1FFE  /* mask for ITR register value */
#define I40E_MIN_ITR                 2  /* reg uses 2 usec resolution */
#define I40E_ITR_100K               10  /* all values below must be even */
#define I40E_ITR_50K                20
#define I40E_ITR_20K                50
#define I40E_ITR_18K                60
#define I40E_ITR_8K                122
#define I40E_MAX_ITR              8160  /* maximum value as per datasheet */
#define ITR_TO_REG(setting) ((setting) & ~I40E_ITR_DYNAMIC)
#define ITR_REG_ALIGN(setting) __ALIGN_MASK(setting, ~I40E_ITR_MASK)
#define ITR_IS_DYNAMIC(setting) (!!((setting) & I40E_ITR_DYNAMIC))

#define I40E_ITR_RX_DEF         (I40E_ITR_20K | I40E_ITR_DYNAMIC)
#define I40E_ITR_TX_DEF         (I40E_ITR_20K | I40E_ITR_DYNAMIC)

/* 0x40 is the enable bit for interrupt rate limiting, and must be set if
 * the value of the rate limit is non-zero
 */
#define INTRL_ENA                  BIT(6)
#define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
#define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)

/**
 * i40e_intrl_usec_to_reg - convert interrupt rate limit to register
 * @intrl: interrupt rate limit to convert
 *
 * This function converts a decimal interrupt rate limit to the appropriate
 * register format expected by the firmware when setting interrupt rate limit.
 */
static inline u16 i40e_intrl_usec_to_reg(int intrl)
{
        if (intrl >> 2)
                return ((intrl >> 2) | INTRL_ENA);
        else
                return 0;
}
#define I40E_INTRL_8K              125     /* 8000 ints/sec */
#define I40E_INTRL_62K             16      /* 62500 ints/sec */
#define I40E_INTRL_83K             12      /* 83333 ints/sec */

#define I40E_QUEUE_END_OF_LIST 0x7FF

/* this enum matches hardware bits and is meant to be used by DYN_CTLN
 * registers and QINT registers or more generally anywhere in the manual
 * mentioning ITR_INDX, ITR_NONE cannot be used as an index 'n' into any
 * register but instead is a special value meaning "don't update" ITR0/1/2.
 */
enum i40e_dyn_idx_t {
        I40E_IDX_ITR0 = 0,
        I40E_IDX_ITR1 = 1,
        I40E_IDX_ITR2 = 2,
        I40E_ITR_NONE = 3       /* ITR_NONE must not be used as an index */
};

/* these are indexes into ITRN registers */
#define I40E_RX_ITR    I40E_IDX_ITR0
#define I40E_TX_ITR    I40E_IDX_ITR1
#define I40E_PE_ITR    I40E_IDX_ITR2

/* Supported RSS offloads */
#define I40E_DEFAULT_RSS_HENA ( \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_UDP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_SCTP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_TCP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_OTHER) | \
        BIT_ULL(I40E_FILTER_PCTYPE_FRAG_IPV4) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_UDP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_TCP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_SCTP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_OTHER) | \
        BIT_ULL(I40E_FILTER_PCTYPE_FRAG_IPV6) | \
        BIT_ULL(I40E_FILTER_PCTYPE_L2_PAYLOAD))

#define I40E_DEFAULT_RSS_HENA_EXPANDED (I40E_DEFAULT_RSS_HENA | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_TCP_SYN_NO_ACK) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_UNICAST_IPV4_UDP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_MULTICAST_IPV4_UDP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_TCP_SYN_NO_ACK) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_UNICAST_IPV6_UDP) | \
        BIT_ULL(I40E_FILTER_PCTYPE_NONF_MULTICAST_IPV6_UDP))

#define i40e_pf_get_default_rss_hena(pf) \
        (((pf)->hw_features & I40E_HW_MULTIPLE_TCP_UDP_RSS_PCTYPE) ? \
          I40E_DEFAULT_RSS_HENA_EXPANDED : I40E_DEFAULT_RSS_HENA)

/* Supported Rx Buffer Sizes (a multiple of 128) */
#define I40E_RXBUFFER_256   256
#define I40E_RXBUFFER_1536  1536  /* 128B aligned standard Ethernet frame */
#define I40E_RXBUFFER_2048  2048
#define I40E_RXBUFFER_3072  3072  /* Used for large frames w/ padding */
#define I40E_MAX_RXBUFFER   9728  /* largest size for single descriptor */

/* NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
 * reserve 2 more, and skb_shared_info adds an additional 384 bytes more,
 * this adds up to 512 bytes of extra data meaning the smallest allocation
 * we could have is 1K.
 * i.e. RXBUFFER_256 --> 960 byte skb (size-1024 slab)
 * i.e. RXBUFFER_512 --> 1216 byte skb (size-2048 slab)
 */
#define I40E_RX_HDR_SIZE I40E_RXBUFFER_256
#define I40E_PACKET_HDR_PAD (ETH_HLEN + ETH_FCS_LEN + (VLAN_HLEN * 2))
#define i40e_rx_desc i40e_32byte_rx_desc

#define I40E_RX_DMA_ATTR \
        (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)

/* Attempt to maximize the headroom available for incoming frames.  We
 * use a 2K buffer for receives and need 1536/1534 to store the data for
 * the frame.  This leaves us with 512 bytes of room.  From that we need
 * to deduct the space needed for the shared info and the padding needed
 * to IP align the frame.
 *
 * Note: For cache line sizes 256 or larger this value is going to end
 *       up negative.  In these cases we should fall back to the legacy
 *       receive path.
 */
#if (PAGE_SIZE < 8192)
#define I40E_2K_TOO_SMALL_WITH_PADDING \
((NET_SKB_PAD + I40E_RXBUFFER_1536) > SKB_WITH_OVERHEAD(I40E_RXBUFFER_2048))

static inline int i40e_compute_pad(int rx_buf_len)
{
        int page_size, pad_size;

        page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2);
        pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len;

        return pad_size;
}

static inline int i40e_skb_pad(void)
{
        int rx_buf_len;

        /* If a 2K buffer cannot handle a standard Ethernet frame then
         * optimize padding for a 3K buffer instead of a 1.5K buffer.
         *
         * For a 3K buffer we need to add enough padding to allow for
         * tailroom due to NET_IP_ALIGN possibly shifting us out of
         * cache-line alignment.
         */
        if (I40E_2K_TOO_SMALL_WITH_PADDING)
                rx_buf_len = I40E_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN);
        else
                rx_buf_len = I40E_RXBUFFER_1536;

        /* if needed make room for NET_IP_ALIGN */
        rx_buf_len -= NET_IP_ALIGN;

        return i40e_compute_pad(rx_buf_len);
}

#define I40E_SKB_PAD i40e_skb_pad()
#else
#define I40E_2K_TOO_SMALL_WITH_PADDING false
#define I40E_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
#endif

/**
 * i40e_test_staterr - tests bits in Rx descriptor status and error fields
 * @rx_desc: pointer to receive descriptor (in le64 format)
 * @stat_err_bits: value to mask
 *
 * This function does some fast chicanery in order to return the
 * value of the mask which is really only used for boolean tests.
 * The status_error_len doesn't need to be shifted because it begins
 * at offset zero.
 */
static inline bool i40e_test_staterr(union i40e_rx_desc *rx_desc,
                                     const u64 stat_err_bits)
{
        return !!(rx_desc->wb.qword1.status_error_len &
                  cpu_to_le64(stat_err_bits));
}

/* How many Rx Buffers do we bundle into one write to the hardware ? */
#define I40E_RX_BUFFER_WRITE    32      /* Must be power of 2 */
#define I40E_RX_INCREMENT(r, i) \
        do {                                    \
                (i)++;                          \
                if ((i) == (r)->count)          \
                        i = 0;                  \
                r->next_to_clean = i;           \
        } while (0)

#define I40E_RX_NEXT_DESC(r, i, n)              \
        do {                                    \
                (i)++;                          \
                if ((i) == (r)->count)          \
                        i = 0;                  \
                (n) = I40E_RX_DESC((r), (i));   \
        } while (0)

#define I40E_RX_NEXT_DESC_PREFETCH(r, i, n)             \
        do {                                            \
                I40E_RX_NEXT_DESC((r), (i), (n));       \
                prefetch((n));                          \
        } while (0)

#define I40E_MAX_BUFFER_TXD     8
#define I40E_MIN_TX_LEN         17

/* The size limit for a transmit buffer in a descriptor is (16K - 1).
 * In order to align with the read requests we will align the value to
 * the nearest 4K which represents our maximum read request size.
 */
#define I40E_MAX_READ_REQ_SIZE          4096
#define I40E_MAX_DATA_PER_TXD           (16 * 1024 - 1)
#define I40E_MAX_DATA_PER_TXD_ALIGNED \
        (I40E_MAX_DATA_PER_TXD & ~(I40E_MAX_READ_REQ_SIZE - 1))

/**
 * i40e_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) + 1;
 *
 * Since multiplication and division are commutative, we can reorder
 * operations into:
 *     return ((size * 85) >> 20) + 1;
 */
static inline unsigned int i40e_txd_use_count(unsigned int size)
{
        return ((size * 85) >> 20) + 1;
}

/* Tx Descriptors needed, worst case */
#define DESC_NEEDED (MAX_SKB_FRAGS + 6)
#define I40E_MIN_DESC_PENDING   4

#define I40E_TX_FLAGS_HW_VLAN           BIT(1)
#define I40E_TX_FLAGS_SW_VLAN           BIT(2)
#define I40E_TX_FLAGS_TSO               BIT(3)
#define I40E_TX_FLAGS_IPV4              BIT(4)
#define I40E_TX_FLAGS_IPV6              BIT(5)
#define I40E_TX_FLAGS_FCCRC             BIT(6)
#define I40E_TX_FLAGS_FSO               BIT(7)
#define I40E_TX_FLAGS_TSYN              BIT(8)
#define I40E_TX_FLAGS_FD_SB             BIT(9)
#define I40E_TX_FLAGS_UDP_TUNNEL        BIT(10)
#define I40E_TX_FLAGS_VLAN_MASK         0xffff0000
#define I40E_TX_FLAGS_VLAN_PRIO_MASK    0xe0000000
#define I40E_TX_FLAGS_VLAN_PRIO_SHIFT   29
#define I40E_TX_FLAGS_VLAN_SHIFT        16

struct i40e_tx_buffer {
        struct i40e_tx_desc *next_to_watch;
        union {
                struct sk_buff *skb;
                void *raw_buf;
        };
        unsigned int bytecount;
        unsigned short gso_segs;

        DEFINE_DMA_UNMAP_ADDR(dma);
        DEFINE_DMA_UNMAP_LEN(len);
        u32 tx_flags;
};

struct i40e_rx_buffer {
        dma_addr_t dma;
        struct page *page;
#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
        __u32 page_offset;
#else
        __u16 page_offset;
#endif
        __u16 pagecnt_bias;
};

struct i40e_queue_stats {
        u64 packets;
        u64 bytes;
};

struct i40e_tx_queue_stats {
        u64 restart_queue;
        u64 tx_busy;
        u64 tx_done_old;
        u64 tx_linearize;
        u64 tx_force_wb;
        int prev_pkt_ctr;
};

struct i40e_rx_queue_stats {
        u64 non_eop_descs;
        u64 alloc_page_failed;
        u64 alloc_buff_failed;
        u64 page_reuse_count;
        u64 realloc_count;
};

enum i40e_ring_state_t {
        __I40E_TX_FDIR_INIT_DONE,
        __I40E_TX_XPS_INIT_DONE,
        __I40E_RING_STATE_NBITS /* must be last */
};

/* some useful defines for virtchannel interface, which
 * is the only remaining user of header split
 */
#define I40E_RX_DTYPE_NO_SPLIT      0
#define I40E_RX_DTYPE_HEADER_SPLIT  1
#define I40E_RX_DTYPE_SPLIT_ALWAYS  2
#define I40E_RX_SPLIT_L2      0x1
#define I40E_RX_SPLIT_IP      0x2
#define I40E_RX_SPLIT_TCP_UDP 0x4
#define I40E_RX_SPLIT_SCTP    0x8

/* struct that defines a descriptor ring, associated with a VSI */
struct i40e_ring {
        struct i40e_ring *next;         /* pointer to next ring in q_vector */
        void *desc;                     /* Descriptor ring memory */
        struct device *dev;             /* Used for DMA mapping */
        struct net_device *netdev;      /* netdev ring maps to */
        struct bpf_prog *xdp_prog;
        union {
                struct i40e_tx_buffer *tx_bi;
                struct i40e_rx_buffer *rx_bi;
        };
        DECLARE_BITMAP(state, __I40E_RING_STATE_NBITS);
        u16 queue_index;                /* Queue number of ring */
        u8 dcb_tc;                      /* Traffic class of ring */
        u8 __iomem *tail;

        /* high bit set means dynamic, use accessor routines to read/write.
         * hardware only supports 2us resolution for the ITR registers.
         * these values always store the USER setting, and must be converted
         * before programming to a register.
         */
        u16 itr_setting;

        u16 count;                      /* Number of descriptors */
        u16 reg_idx;                    /* HW register index of the ring */
        u16 rx_buf_len;

        /* used in interrupt processing */
        u16 next_to_use;
        u16 next_to_clean;

        u8 atr_sample_rate;
        u8 atr_count;

        bool ring_active;               /* is ring online or not */
        bool arm_wb;            /* do something to arm write back */
        u8 packet_stride;

        u16 flags;
#define I40E_TXR_FLAGS_WB_ON_ITR                BIT(0)
#define I40E_RXR_FLAGS_BUILD_SKB_ENABLED        BIT(1)
#define I40E_TXR_FLAGS_XDP                      BIT(2)

        /* stats structs */
        struct i40e_queue_stats stats;
        struct u64_stats_sync syncp;
        union {
                struct i40e_tx_queue_stats tx_stats;
                struct i40e_rx_queue_stats rx_stats;
        };

        unsigned int size;              /* length of descriptor ring in bytes */
        dma_addr_t dma;                 /* physical address of ring */

        struct i40e_vsi *vsi;           /* Backreference to associated VSI */
        struct i40e_q_vector *q_vector; /* Backreference to associated vector */

        struct rcu_head rcu;            /* to avoid race on free */
        u16 next_to_alloc;
        struct sk_buff *skb;            /* When i40e_clean_rx_ring_irq() must
                                         * return before it sees the EOP for
                                         * the current packet, we save that skb
                                         * here and resume receiving this
                                         * packet the next time
                                         * i40e_clean_rx_ring_irq() is called
                                         * for this ring.
                                         */

        struct i40e_channel *ch;
        struct xdp_rxq_info xdp_rxq;
} ____cacheline_internodealigned_in_smp;

static inline bool ring_uses_build_skb(struct i40e_ring *ring)
{
        return !!(ring->flags & I40E_RXR_FLAGS_BUILD_SKB_ENABLED);
}

static inline void set_ring_build_skb_enabled(struct i40e_ring *ring)
{
        ring->flags |= I40E_RXR_FLAGS_BUILD_SKB_ENABLED;
}

static inline void clear_ring_build_skb_enabled(struct i40e_ring *ring)
{
        ring->flags &= ~I40E_RXR_FLAGS_BUILD_SKB_ENABLED;
}

static inline bool ring_is_xdp(struct i40e_ring *ring)
{
        return !!(ring->flags & I40E_TXR_FLAGS_XDP);
}

static inline void set_ring_xdp(struct i40e_ring *ring)
{
        ring->flags |= I40E_TXR_FLAGS_XDP;
}

#define I40E_ITR_ADAPTIVE_MIN_INC       0x0002
#define I40E_ITR_ADAPTIVE_MIN_USECS     0x0002
#define I40E_ITR_ADAPTIVE_MAX_USECS     0x007e
#define I40E_ITR_ADAPTIVE_LATENCY       0x8000
#define I40E_ITR_ADAPTIVE_BULK          0x0000
#define ITR_IS_BULK(x) (!((x) & I40E_ITR_ADAPTIVE_LATENCY))

struct i40e_ring_container {
        struct i40e_ring *ring;         /* pointer to linked list of ring(s) */
        unsigned long next_update;      /* jiffies value of next update */
        unsigned int total_bytes;       /* total bytes processed this int */
        unsigned int total_packets;     /* total packets processed this int */
        u16 count;
        u16 target_itr;                 /* target ITR setting for ring(s) */
        u16 current_itr;                /* current ITR setting for ring(s) */
};

/* iterator for handling rings in ring container */
#define i40e_for_each_ring(pos, head) \
        for (pos = (head).ring; pos != NULL; pos = pos->next)

static inline unsigned int i40e_rx_pg_order(struct i40e_ring *ring)
{
#if (PAGE_SIZE < 8192)
        if (ring->rx_buf_len > (PAGE_SIZE / 2))
                return 1;
#endif
        return 0;
}

#define i40e_rx_pg_size(_ring) (PAGE_SIZE << i40e_rx_pg_order(_ring))

bool i40e_alloc_rx_buffers(struct i40e_ring *rxr, u16 cleaned_count);
netdev_tx_t i40e_lan_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
void i40e_clean_tx_ring(struct i40e_ring *tx_ring);
void i40e_clean_rx_ring(struct i40e_ring *rx_ring);
int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring);
int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring);
void i40e_free_tx_resources(struct i40e_ring *tx_ring);
void i40e_free_rx_resources(struct i40e_ring *rx_ring);
int i40e_napi_poll(struct napi_struct *napi, int budget);
void i40e_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector);
u32 i40e_get_tx_pending(struct i40e_ring *ring, bool in_sw);
void i40e_detect_recover_hung(struct i40e_vsi *vsi);
int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
bool __i40e_chk_linearize(struct sk_buff *skb);
int i40e_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp);
void i40e_xdp_flush(struct net_device *dev);

/**
 * i40e_get_head - Retrieve head from head writeback
 * @tx_ring:  tx ring to fetch head of
 *
 * Returns value of Tx ring head based on value stored
 * in head write-back location
 **/
static inline u32 i40e_get_head(struct i40e_ring *tx_ring)
{
        void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count;

        return le32_to_cpu(*(volatile __le32 *)head);
}

/**
 * i40e_xmit_descriptor_count - calculate number of Tx descriptors needed
 * @skb:     send buffer
 * @tx_ring: ring to send buffer on
 *
 * Returns number of data descriptors needed for this skb. Returns 0 to indicate
 * there is not enough descriptors available in this ring since we need at least
 * one descriptor.
 **/
static inline int i40e_xmit_descriptor_count(struct sk_buff *skb)
{
        const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
        unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
        int count = 0, size = skb_headlen(skb);

        for (;;) {
                count += i40e_txd_use_count(size);

                if (!nr_frags--)
                        break;

                size = skb_frag_size(frag++);
        }

        return count;
}

/**
 * i40e_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 inline int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
{
        if (likely(I40E_DESC_UNUSED(tx_ring) >= size))
                return 0;
        return __i40e_maybe_stop_tx(tx_ring, size);
}

/**
 * i40e_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 inline bool i40e_chk_linearize(struct sk_buff *skb, int count)
{
        /* Both TSO and single send will work if count is less than 8 */
        if (likely(count < I40E_MAX_BUFFER_TXD))
                return false;

        if (skb_is_gso(skb))
                return __i40e_chk_linearize(skb);

        /* we can support up to 8 data buffers for a single send */
        return count != I40E_MAX_BUFFER_TXD;
}

/**
 * txring_txq - Find the netdev Tx ring based on the i40e Tx ring
 * @ring: Tx ring to find the netdev equivalent of
 **/
static inline struct netdev_queue *txring_txq(const struct i40e_ring *ring)
{
        return netdev_get_tx_queue(ring->netdev, ring->queue_index);
}
#endif /* _I40E_TXRX_H_ */