/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2010-2016 Solarflare Communications Inc.
 * All rights reserved.
 *
 * This software was developed in part by Philip Paeps under contract for
 * Solarflare Communications, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are
 * those of the authors and should not be interpreted as representing official
 * policies, either expressed or implied, of the FreeBSD Project.
 */

#ifndef _SFXGE_TX_H
#define _SFXGE_TX_H

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>

/* If defined, parse TX packets directly in if_transmit
 * for better cache locality and reduced time under TX lock
 */
#define SFXGE_TX_PARSE_EARLY 1

/* Maximum size of TSO packet */
#define SFXGE_TSO_MAX_SIZE              (65535)

/*
 * Maximum number of segments to be created for a TSO packet.
 * Allow for a reasonable minimum MSS of 512.
 */
#define SFXGE_TSO_MAX_SEGS              howmany(SFXGE_TSO_MAX_SIZE, 512)

/* Maximum number of DMA segments needed to map an mbuf chain.  With
 * TSO, the mbuf length may be just over 64K, divided into 2K mbuf
 * clusters taking into account that the first may be not 2K cluster
 * boundary aligned.
 * Packet header may be split into two segments because of, for example,
 * VLAN header insertion.
 * The chain could be longer than this initially, but can be shortened
 * with m_collapse().
 */
#define SFXGE_TX_MAPPING_MAX_SEG                                        \
        (2 + howmany(SFXGE_TSO_MAX_SIZE, MCLBYTES) + 1)

/*
 * Buffer mapping flags.
 *
 * Buffers and DMA mappings must be freed when the last descriptor
 * referring to them is completed.  Set the TX_BUF_UNMAP and
 * TX_BUF_MBUF flags on the last descriptor generated for an mbuf
 * chain.  Set only the TX_BUF_UNMAP flag on a descriptor referring to
 * a heap buffer.
 */
enum sfxge_tx_buf_flags {
        TX_BUF_UNMAP = 1,
        TX_BUF_MBUF = 2,
};

/*
 * Buffer mapping information for descriptors in flight.
 */
struct sfxge_tx_mapping {
        union {
                struct mbuf     *mbuf;
                caddr_t         heap_buf;
        }                       u;
        bus_dmamap_t            map;
        enum sfxge_tx_buf_flags flags;
};

#define SFXGE_TX_DPL_GET_PKT_LIMIT_DEFAULT              (64 * 1024)
#define SFXGE_TX_DPL_GET_NON_TCP_PKT_LIMIT_DEFAULT      1024
#define SFXGE_TX_DPL_PUT_PKT_LIMIT_DEFAULT              1024

/*
 * Deferred packet list.
 */
struct sfxge_tx_dpl {
        unsigned int    std_get_max;            /* Maximum number  of packets
                                                 * in get list */
        unsigned int    std_get_non_tcp_max;    /* Maximum number
                                                 * of non-TCP packets
                                                 * in get list */
        unsigned int    std_put_max;            /* Maximum number of packets
                                                 * in put list */
        uintptr_t       std_put;                /* Head of put list. */
        struct mbuf     *std_get;               /* Head of get list. */
        struct mbuf     **std_getp;             /* Tail of get list. */
        unsigned int    std_get_count;          /* Packets in get list. */
        unsigned int    std_get_non_tcp_count;  /* Non-TCP packets
                                                 * in get list */
        unsigned int    std_get_hiwat;          /* Packets in get list
                                                 * high watermark */
        unsigned int    std_put_hiwat;          /* Packets in put list
                                                 * high watermark */
};

#define SFXGE_TX_BUFFER_SIZE    0x400
#define SFXGE_TX_HEADER_SIZE    0x100
#define SFXGE_TX_COPY_THRESHOLD 0x200

enum sfxge_txq_state {
        SFXGE_TXQ_UNINITIALIZED = 0,
        SFXGE_TXQ_INITIALIZED,
        SFXGE_TXQ_STARTED
};

enum sfxge_txq_type {
        SFXGE_TXQ_NON_CKSUM = 0,
        SFXGE_TXQ_IP_CKSUM,
        SFXGE_TXQ_IP_TCP_UDP_CKSUM,
        SFXGE_TXQ_NTYPES
};

#define SFXGE_EVQ0_N_TXQ(_sc)                                           \
        ((_sc)->txq_dynamic_cksum_toggle_supported ?                    \
        1 : SFXGE_TXQ_NTYPES)

#define SFXGE_TXQ_UNBLOCK_LEVEL(_entries)       (EFX_TXQ_LIMIT(_entries) / 4)

#define SFXGE_TX_BATCH  64

#define SFXGE_TXQ_LOCK_INIT(_txq, _ifname, _txq_index)                  \
        do {                                                            \
                struct sfxge_txq  *__txq = (_txq);                      \
                                                                        \
                snprintf((__txq)->lock_name,                            \
                         sizeof((__txq)->lock_name),                    \
                         "%s:txq%u", (_ifname), (_txq_index));          \
                mtx_init(&(__txq)->lock, (__txq)->lock_name,            \
                         NULL, MTX_DEF);                                \
        } while (B_FALSE)
#define SFXGE_TXQ_LOCK_DESTROY(_txq)                                    \
        mtx_destroy(&(_txq)->lock)
#define SFXGE_TXQ_LOCK(_txq)                                            \
        mtx_lock(&(_txq)->lock)
#define SFXGE_TXQ_TRYLOCK(_txq)                                         \
        mtx_trylock(&(_txq)->lock)
#define SFXGE_TXQ_UNLOCK(_txq)                                          \
        mtx_unlock(&(_txq)->lock)
#define SFXGE_TXQ_LOCK_ASSERT_OWNED(_txq)                               \
        mtx_assert(&(_txq)->lock, MA_OWNED)
#define SFXGE_TXQ_LOCK_ASSERT_NOTOWNED(_txq)                            \
        mtx_assert(&(_txq)->lock, MA_NOTOWNED)

struct sfxge_txq {
        /* The following fields should be written very rarely */
        struct sfxge_softc              *sc;
        enum sfxge_txq_state            init_state;
        enum sfxge_flush_state          flush_state;
        unsigned int                    tso_fw_assisted;
        enum sfxge_txq_type             type;
        unsigned int                    evq_index;
        efsys_mem_t                     mem;
        unsigned int                    buf_base_id;
        unsigned int                    entries;
        unsigned int                    ptr_mask;
        unsigned int                    max_pkt_desc;

        struct sfxge_tx_mapping         *stmp;  /* Packets in flight. */
        bus_dma_tag_t                   packet_dma_tag;
        efx_desc_t                      *pend_desc;
        efx_txq_t                       *common;

        efsys_mem_t                     *tsoh_buffer;

        char                            lock_name[SFXGE_LOCK_NAME_MAX];

        /* This field changes more often and is read regularly on both
         * the initiation and completion paths
         */
        int                             blocked __aligned(CACHE_LINE_SIZE);

        /* The following fields change more often, and are used mostly
         * on the initiation path
         */
        struct mtx                      lock __aligned(CACHE_LINE_SIZE);
        struct sfxge_tx_dpl             dpl;    /* Deferred packet list. */
        unsigned int                    n_pend_desc;
        unsigned int                    added;
        unsigned int                    reaped;

        /* The last (or constant) set of HW offloads requested on the queue */
        uint16_t                        hw_cksum_flags;

        /* The last VLAN TCI seen on the queue if FW-assisted tagging is
           used */
        uint16_t                        hw_vlan_tci;

        /* Statistics */
        unsigned long                   tso_bursts;
        unsigned long                   tso_packets;
        unsigned long                   tso_long_headers;
        unsigned long                   collapses;
        unsigned long                   drops;
        unsigned long                   get_overflow;
        unsigned long                   get_non_tcp_overflow;
        unsigned long                   put_overflow;
        unsigned long                   netdown_drops;
        unsigned long                   tso_pdrop_too_many;
        unsigned long                   tso_pdrop_no_rsrc;

        /* The following fields change more often, and are used mostly
         * on the completion path
         */
        unsigned int                    pending __aligned(CACHE_LINE_SIZE);
        unsigned int                    completed;
        struct sfxge_txq                *next;
};

struct sfxge_evq;

extern uint64_t sfxge_tx_get_drops(struct sfxge_softc *sc);

extern int sfxge_tx_init(struct sfxge_softc *sc);
extern void sfxge_tx_fini(struct sfxge_softc *sc);
extern int sfxge_tx_start(struct sfxge_softc *sc);
extern void sfxge_tx_stop(struct sfxge_softc *sc);
extern void sfxge_tx_qcomplete(struct sfxge_txq *txq, struct sfxge_evq *evq);
extern void sfxge_tx_qflush_done(struct sfxge_txq *txq);
extern void sfxge_if_qflush(if_t ifp);
extern int sfxge_if_transmit(if_t ifp, struct mbuf *m);

#endif