ixgbe: add MAC short packet discard count to Rx errors

[dpdk.git] / drivers / net / cxgbe / sge.c

/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2014-2015 Chelsio Communications.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Chelsio Communications nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   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.
 */

#include <sys/queue.h>
#include <stdio.h>
#include <errno.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <stdarg.h>
#include <inttypes.h>
#include <netinet/in.h>

#include <rte_byteorder.h>
#include <rte_common.h>
#include <rte_cycles.h>
#include <rte_interrupts.h>
#include <rte_log.h>
#include <rte_debug.h>
#include <rte_pci.h>
#include <rte_atomic.h>
#include <rte_branch_prediction.h>
#include <rte_memory.h>
#include <rte_memzone.h>
#include <rte_tailq.h>
#include <rte_eal.h>
#include <rte_alarm.h>
#include <rte_ether.h>
#include <rte_ethdev.h>
#include <rte_atomic.h>
#include <rte_malloc.h>
#include <rte_random.h>
#include <rte_dev.h>

#include "common.h"
#include "t4_regs.h"
#include "t4_msg.h"
#include "cxgbe.h"

static inline void ship_tx_pkt_coalesce_wr(struct adapter *adap,
                                           struct sge_eth_txq *txq);

/*
 * Max number of Rx buffers we replenish at a time.
 */
#define MAX_RX_REFILL 64U

#define NOMEM_TMR_IDX (SGE_NTIMERS - 1)

/*
 * Max Tx descriptor space we allow for an Ethernet packet to be inlined
 * into a WR.
 */
#define MAX_IMM_TX_PKT_LEN 256

/*
 * Rx buffer sizes for "usembufs" Free List buffers (one ingress packet
 * per mbuf buffer).  We currently only support two sizes for 1500- and
 * 9000-byte MTUs. We could easily support more but there doesn't seem to be
 * much need for that ...
 */
#define FL_MTU_SMALL 1500
#define FL_MTU_LARGE 9000

static inline unsigned int fl_mtu_bufsize(struct adapter *adapter,
                                          unsigned int mtu)
{
        struct sge *s = &adapter->sge;

        return CXGBE_ALIGN(s->pktshift + ETHER_HDR_LEN + VLAN_HLEN + mtu,
                           s->fl_align);
}

#define FL_MTU_SMALL_BUFSIZE(adapter) fl_mtu_bufsize(adapter, FL_MTU_SMALL)
#define FL_MTU_LARGE_BUFSIZE(adapter) fl_mtu_bufsize(adapter, FL_MTU_LARGE)

/*
 * Bits 0..3 of rx_sw_desc.dma_addr have special meaning.  The hardware uses
 * these to specify the buffer size as an index into the SGE Free List Buffer
 * Size register array.  We also use bit 4, when the buffer has been unmapped
 * for DMA, but this is of course never sent to the hardware and is only used
 * to prevent double unmappings.  All of the above requires that the Free List
 * Buffers which we allocate have the bottom 5 bits free (0) -- i.e. are
 * 32-byte or or a power of 2 greater in alignment.  Since the SGE's minimal
 * Free List Buffer alignment is 32 bytes, this works out for us ...
 */
enum {
        RX_BUF_FLAGS     = 0x1f,   /* bottom five bits are special */
        RX_BUF_SIZE      = 0x0f,   /* bottom three bits are for buf sizes */
        RX_UNMAPPED_BUF  = 0x10,   /* buffer is not mapped */

        /*
         * XXX We shouldn't depend on being able to use these indices.
         * XXX Especially when some other Master PF has initialized the
         * XXX adapter or we use the Firmware Configuration File.  We
         * XXX should really search through the Host Buffer Size register
         * XXX array for the appropriately sized buffer indices.
         */
        RX_SMALL_PG_BUF  = 0x0,   /* small (PAGE_SIZE) page buffer */
        RX_LARGE_PG_BUF  = 0x1,   /* buffer large page buffer */

        RX_SMALL_MTU_BUF = 0x2,   /* small MTU buffer */
        RX_LARGE_MTU_BUF = 0x3,   /* large MTU buffer */
};

/**
 * txq_avail - return the number of available slots in a Tx queue
 * @q: the Tx queue
 *
 * Returns the number of descriptors in a Tx queue available to write new
 * packets.
 */
static inline unsigned int txq_avail(const struct sge_txq *q)
{
        return q->size - 1 - q->in_use;
}

static int map_mbuf(struct rte_mbuf *mbuf, dma_addr_t *addr)
{
        struct rte_mbuf *m = mbuf;

        for (; m; m = m->next, addr++) {
                *addr = m->buf_physaddr + rte_pktmbuf_headroom(m);
                if (*addr == 0)
                        goto out_err;
        }
        return 0;

out_err:
        return -ENOMEM;
}

/**
 * free_tx_desc - reclaims Tx descriptors and their buffers
 * @q: the Tx queue to reclaim descriptors from
 * @n: the number of descriptors to reclaim
 *
 * Reclaims Tx descriptors from an SGE Tx queue and frees the associated
 * Tx buffers.  Called with the Tx queue lock held.
 */
static void free_tx_desc(struct sge_txq *q, unsigned int n)
{
        struct tx_sw_desc *d;
        unsigned int cidx = 0;

        d = &q->sdesc[cidx];
        while (n--) {
                if (d->mbuf) {                       /* an SGL is present */
                        rte_pktmbuf_free(d->mbuf);
                        d->mbuf = NULL;
                }
                if (d->coalesce.idx) {
                        int i;

                        for (i = 0; i < d->coalesce.idx; i++) {
                                rte_pktmbuf_free(d->coalesce.mbuf[i]);
                                d->coalesce.mbuf[i] = NULL;
                        }
                        d->coalesce.idx = 0;
                }
                ++d;
                if (++cidx == q->size) {
                        cidx = 0;
                        d = q->sdesc;
                }
                RTE_MBUF_PREFETCH_TO_FREE(&q->sdesc->mbuf->pool);
        }
}

static void reclaim_tx_desc(struct sge_txq *q, unsigned int n)
{
        struct tx_sw_desc *d;
        unsigned int cidx = q->cidx;

        d = &q->sdesc[cidx];
        while (n--) {
                if (d->mbuf) {                       /* an SGL is present */
                        rte_pktmbuf_free(d->mbuf);
                        d->mbuf = NULL;
                }
                ++d;
                if (++cidx == q->size) {
                        cidx = 0;
                        d = q->sdesc;
                }
        }
        q->cidx = cidx;
}

/**
 * fl_cap - return the capacity of a free-buffer list
 * @fl: the FL
 *
 * Returns the capacity of a free-buffer list.  The capacity is less than
 * the size because one descriptor needs to be left unpopulated, otherwise
 * HW will think the FL is empty.
 */
static inline unsigned int fl_cap(const struct sge_fl *fl)
{
        return fl->size - 8;   /* 1 descriptor = 8 buffers */
}

/**
 * fl_starving - return whether a Free List is starving.
 * @adapter: pointer to the adapter
 * @fl: the Free List
 *
 * Tests specified Free List to see whether the number of buffers
 * available to the hardware has falled below our "starvation"
 * threshold.
 */
static inline bool fl_starving(const struct adapter *adapter,
                               const struct sge_fl *fl)
{
        const struct sge *s = &adapter->sge;

        return fl->avail - fl->pend_cred <= s->fl_starve_thres;
}

static inline unsigned int get_buf_size(struct adapter *adapter,
                                        const struct rx_sw_desc *d)
{
        unsigned int rx_buf_size_idx = d->dma_addr & RX_BUF_SIZE;
        unsigned int buf_size = 0;

        switch (rx_buf_size_idx) {
        case RX_SMALL_MTU_BUF:
                buf_size = FL_MTU_SMALL_BUFSIZE(adapter);
                break;

        case RX_LARGE_MTU_BUF:
                buf_size = FL_MTU_LARGE_BUFSIZE(adapter);
                break;

        default:
                BUG_ON(1);
                /* NOT REACHED */
        }

        return buf_size;
}

/**
 * free_rx_bufs - free the Rx buffers on an SGE free list
 * @q: the SGE free list to free buffers from
 * @n: how many buffers to free
 *
 * Release the next @n buffers on an SGE free-buffer Rx queue.   The
 * buffers must be made inaccessible to HW before calling this function.
 */
static void free_rx_bufs(struct sge_fl *q, int n)
{
        unsigned int cidx = q->cidx;
        struct rx_sw_desc *d;

        d = &q->sdesc[cidx];
        while (n--) {
                if (d->buf) {
                        rte_pktmbuf_free(d->buf);
                        d->buf = NULL;
                }
                ++d;
                if (++cidx == q->size) {
                        cidx = 0;
                        d = q->sdesc;
                }
                q->avail--;
        }
        q->cidx = cidx;
}

/**
 * unmap_rx_buf - unmap the current Rx buffer on an SGE free list
 * @q: the SGE free list
 *
 * Unmap the current buffer on an SGE free-buffer Rx queue.   The
 * buffer must be made inaccessible to HW before calling this function.
 *
 * This is similar to @free_rx_bufs above but does not free the buffer.
 * Do note that the FL still loses any further access to the buffer.
 */
static void unmap_rx_buf(struct sge_fl *q)
{
        if (++q->cidx == q->size)
                q->cidx = 0;
        q->avail--;
}

static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q)
{
        if (q->pend_cred >= 64) {
                u32 val = adap->params.arch.sge_fl_db;

                if (is_t4(adap->params.chip))
                        val |= V_PIDX(q->pend_cred / 8);
                else
                        val |= V_PIDX_T5(q->pend_cred / 8);

                /*
                 * Make sure all memory writes to the Free List queue are
                 * committed before we tell the hardware about them.
                 */
                wmb();

                /*
                 * If we don't have access to the new User Doorbell (T5+), use
                 * the old doorbell mechanism; otherwise use the new BAR2
                 * mechanism.
                 */
                if (unlikely(!q->bar2_addr)) {
                        t4_write_reg(adap, MYPF_REG(A_SGE_PF_KDOORBELL),
                                     val | V_QID(q->cntxt_id));
                } else {
                        writel(val | V_QID(q->bar2_qid),
                               (void *)((uintptr_t)q->bar2_addr +
                               SGE_UDB_KDOORBELL));

                        /*
                         * This Write memory Barrier will force the write to
                         * the User Doorbell area to be flushed.
                         */
                        wmb();
                }
                q->pend_cred &= 7;
        }
}

static inline void set_rx_sw_desc(struct rx_sw_desc *sd, void *buf,
                                  dma_addr_t mapping)
{
        sd->buf = buf;
        sd->dma_addr = mapping;      /* includes size low bits */
}

/**
 * refill_fl_usembufs - refill an SGE Rx buffer ring with mbufs
 * @adap: the adapter
 * @q: the ring to refill
 * @n: the number of new buffers to allocate
 *
 * (Re)populate an SGE free-buffer queue with up to @n new packet buffers,
 * allocated with the supplied gfp flags.  The caller must assure that
 * @n does not exceed the queue's capacity.  If afterwards the queue is
 * found critically low mark it as starving in the bitmap of starving FLs.
 *
 * Returns the number of buffers allocated.
 */
static unsigned int refill_fl_usembufs(struct adapter *adap, struct sge_fl *q,
                                       int n)
{
        struct sge_eth_rxq *rxq = container_of(q, struct sge_eth_rxq, fl);
        unsigned int cred = q->avail;
        __be64 *d = &q->desc[q->pidx];
        struct rx_sw_desc *sd = &q->sdesc[q->pidx];
        unsigned int buf_size_idx = RX_SMALL_MTU_BUF;
        struct rte_mbuf *buf_bulk[n];
        int ret, i;
        struct rte_pktmbuf_pool_private *mbp_priv;
        u8 jumbo_en = rxq->rspq.eth_dev->data->dev_conf.rxmode.jumbo_frame;

        /* Use jumbo mtu buffers iff mbuf data room size can fit jumbo data. */
        mbp_priv = rte_mempool_get_priv(rxq->rspq.mb_pool);
        if (jumbo_en &&
            ((mbp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM) >= 9000))
                buf_size_idx = RX_LARGE_MTU_BUF;

        ret = rte_mempool_get_bulk(rxq->rspq.mb_pool, (void *)buf_bulk, n);
        if (unlikely(ret != 0)) {
                dev_debug(adap, "%s: failed to allocated fl entries in bulk ..\n",
                          __func__);
                q->alloc_failed++;
                rxq->rspq.eth_dev->data->rx_mbuf_alloc_failed++;
                goto out;
        }

        for (i = 0; i < n; i++) {
                struct rte_mbuf *mbuf = buf_bulk[i];
                dma_addr_t mapping;

                if (!mbuf) {
                        dev_debug(adap, "%s: mbuf alloc failed\n", __func__);
                        q->alloc_failed++;
                        rxq->rspq.eth_dev->data->rx_mbuf_alloc_failed++;
                        goto out;
                }

                rte_mbuf_refcnt_set(mbuf, 1);
                mbuf->data_off = RTE_PKTMBUF_HEADROOM;
                mbuf->next = NULL;
                mbuf->nb_segs = 1;
                mbuf->port = rxq->rspq.port_id;

                mapping = (dma_addr_t)(mbuf->buf_physaddr + mbuf->data_off);
                mapping |= buf_size_idx;
                *d++ = cpu_to_be64(mapping);
                set_rx_sw_desc(sd, mbuf, mapping);
                sd++;

                q->avail++;
                if (++q->pidx == q->size) {
                        q->pidx = 0;
                        sd = q->sdesc;
                        d = q->desc;
                }
        }

out:    cred = q->avail - cred;
        q->pend_cred += cred;
        ring_fl_db(adap, q);

        if (unlikely(fl_starving(adap, q))) {
                /*
                 * Make sure data has been written to free list
                 */
                wmb();
                q->low++;
        }

        return cred;
}

/**
 * refill_fl - refill an SGE Rx buffer ring with mbufs
 * @adap: the adapter
 * @q: the ring to refill
 * @n: the number of new buffers to allocate
 *
 * (Re)populate an SGE free-buffer queue with up to @n new packet buffers,
 * allocated with the supplied gfp flags.  The caller must assure that
 * @n does not exceed the queue's capacity.  Returns the number of buffers
 * allocated.
 */
static unsigned int refill_fl(struct adapter *adap, struct sge_fl *q, int n)
{
        return refill_fl_usembufs(adap, q, n);
}

static inline void __refill_fl(struct adapter *adap, struct sge_fl *fl)
{
        refill_fl(adap, fl, min(MAX_RX_REFILL, fl_cap(fl) - fl->avail));
}

/*
 * Return the number of reclaimable descriptors in a Tx queue.
 */
static inline int reclaimable(const struct sge_txq *q)
{
        int hw_cidx = ntohs(q->stat->cidx);

        hw_cidx -= q->cidx;
        if (hw_cidx < 0)
                return hw_cidx + q->size;
        return hw_cidx;
}

/**
 * reclaim_completed_tx - reclaims completed Tx descriptors
 * @q: the Tx queue to reclaim completed descriptors from
 *
 * Reclaims Tx descriptors that the SGE has indicated it has processed.
 */
void reclaim_completed_tx(struct sge_txq *q)
{
        unsigned int avail = reclaimable(q);

        do {
                /* reclaim as much as possible */
                reclaim_tx_desc(q, avail);
                q->in_use -= avail;
                avail = reclaimable(q);
        } while (avail);
}

/**
 * sgl_len - calculates the size of an SGL of the given capacity
 * @n: the number of SGL entries
 *
 * Calculates the number of flits needed for a scatter/gather list that
 * can hold the given number of entries.
 */
static inline unsigned int sgl_len(unsigned int n)
{
        /*
         * A Direct Scatter Gather List uses 32-bit lengths and 64-bit PCI DMA
         * addresses.  The DSGL Work Request starts off with a 32-bit DSGL
         * ULPTX header, then Length0, then Address0, then, for 1 <= i <= N,
         * repeated sequences of { Length[i], Length[i+1], Address[i],
         * Address[i+1] } (this ensures that all addresses are on 64-bit
         * boundaries).  If N is even, then Length[N+1] should be set to 0 and
         * Address[N+1] is omitted.
         *
         * The following calculation incorporates all of the above.  It's
         * somewhat hard to follow but, briefly: the "+2" accounts for the
         * first two flits which include the DSGL header, Length0 and
         * Address0; the "(3*(n-1))/2" covers the main body of list entries (3
         * flits for every pair of the remaining N) +1 if (n-1) is odd; and
         * finally the "+((n-1)&1)" adds the one remaining flit needed if
         * (n-1) is odd ...
         */
        n--;
        return (3 * n) / 2 + (n & 1) + 2;
}

/**
 * flits_to_desc - returns the num of Tx descriptors for the given flits
 * @n: the number of flits
 *
 * Returns the number of Tx descriptors needed for the supplied number
 * of flits.
 */
static inline unsigned int flits_to_desc(unsigned int n)
{
        return DIV_ROUND_UP(n, 8);
}

/**
 * is_eth_imm - can an Ethernet packet be sent as immediate data?
 * @m: the packet
 *
 * Returns whether an Ethernet packet is small enough to fit as
 * immediate data. Return value corresponds to the headroom required.
 */
static inline int is_eth_imm(const struct rte_mbuf *m)
{
        unsigned int hdrlen = (m->ol_flags & PKT_TX_TCP_SEG) ?
                              sizeof(struct cpl_tx_pkt_lso_core) : 0;

        hdrlen += sizeof(struct cpl_tx_pkt);
        if (m->pkt_len <= MAX_IMM_TX_PKT_LEN - hdrlen)
                return hdrlen;

        return 0;
}

/**
 * calc_tx_flits - calculate the number of flits for a packet Tx WR
 * @m: the packet
 *
 * Returns the number of flits needed for a Tx WR for the given Ethernet
 * packet, including the needed WR and CPL headers.
 */
static inline unsigned int calc_tx_flits(const struct rte_mbuf *m)
{
        unsigned int flits;
        int hdrlen;

        /*
         * If the mbuf is small enough, we can pump it out as a work request
         * with only immediate data.  In that case we just have to have the
         * TX Packet header plus the mbuf data in the Work Request.
         */

        hdrlen = is_eth_imm(m);
        if (hdrlen)
                return DIV_ROUND_UP(m->pkt_len + hdrlen, sizeof(__be64));

        /*
         * Otherwise, we're going to have to construct a Scatter gather list
         * of the mbuf body and fragments.  We also include the flits necessary
         * for the TX Packet Work Request and CPL.  We always have a firmware
         * Write Header (incorporated as part of the cpl_tx_pkt_lso and
         * cpl_tx_pkt structures), followed by either a TX Packet Write CPL
         * message or, if we're doing a Large Send Offload, an LSO CPL message
         * with an embeded TX Packet Write CPL message.
         */
        flits = sgl_len(m->nb_segs);
        if (m->tso_segsz)
                flits += (sizeof(struct fw_eth_tx_pkt_wr) +
                          sizeof(struct cpl_tx_pkt_lso_core) +
                          sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64);
        else
                flits += (sizeof(struct fw_eth_tx_pkt_wr) +
                          sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64);
        return flits;
}

/**
 * write_sgl - populate a scatter/gather list for a packet
 * @mbuf: the packet
 * @q: the Tx queue we are writing into
 * @sgl: starting location for writing the SGL
 * @end: points right after the end of the SGL
 * @start: start offset into mbuf main-body data to include in the SGL
 * @addr: address of mapped region
 *
 * Generates a scatter/gather list for the buffers that make up a packet.
 * The caller must provide adequate space for the SGL that will be written.
 * The SGL includes all of the packet's page fragments and the data in its
 * main body except for the first @start bytes.  @sgl must be 16-byte
 * aligned and within a Tx descriptor with available space.  @end points
 * write after the end of the SGL but does not account for any potential
 * wrap around, i.e., @end > @sgl.
 */
static void write_sgl(struct rte_mbuf *mbuf, struct sge_txq *q,
                      struct ulptx_sgl *sgl, u64 *end, unsigned int start,
                      const dma_addr_t *addr)
{
        unsigned int i, len;
        struct ulptx_sge_pair *to;
        struct rte_mbuf *m = mbuf;
        unsigned int nfrags = m->nb_segs;
        struct ulptx_sge_pair buf[nfrags / 2];

        len = m->data_len - start;
        sgl->len0 = htonl(len);
        sgl->addr0 = rte_cpu_to_be_64(addr[0]);

        sgl->cmd_nsge = htonl(V_ULPTX_CMD(ULP_TX_SC_DSGL) |
                              V_ULPTX_NSGE(nfrags));
        if (likely(--nfrags == 0))
                return;
        /*
         * Most of the complexity below deals with the possibility we hit the
         * end of the queue in the middle of writing the SGL.  For this case
         * only we create the SGL in a temporary buffer and then copy it.
         */
        to = (u8 *)end > (u8 *)q->stat ? buf : sgl->sge;

        for (i = 0; nfrags >= 2; nfrags -= 2, to++) {
                m = m->next;
                to->len[0] = rte_cpu_to_be_32(m->data_len);
                to->addr[0] = rte_cpu_to_be_64(addr[++i]);
                m = m->next;
                to->len[1] = rte_cpu_to_be_32(m->data_len);
                to->addr[1] = rte_cpu_to_be_64(addr[++i]);
        }
        if (nfrags) {
                m = m->next;
                to->len[0] = rte_cpu_to_be_32(m->data_len);
                to->len[1] = rte_cpu_to_be_32(0);
                to->addr[0] = rte_cpu_to_be_64(addr[i + 1]);
        }
        if (unlikely((u8 *)end > (u8 *)q->stat)) {
                unsigned int part0 = RTE_PTR_DIFF((u8 *)q->stat,
                                                  (u8 *)sgl->sge);
                unsigned int part1;

                if (likely(part0))
                        memcpy(sgl->sge, buf, part0);
                part1 = RTE_PTR_DIFF((u8 *)end, (u8 *)q->stat);
                rte_memcpy(q->desc, RTE_PTR_ADD((u8 *)buf, part0), part1);
                end = RTE_PTR_ADD((void *)q->desc, part1);
        }
        if ((uintptr_t)end & 8)           /* 0-pad to multiple of 16 */
                *(u64 *)end = 0;
}

#define IDXDIFF(head, tail, wrap) \
        ((head) >= (tail) ? (head) - (tail) : (wrap) - (tail) + (head))

#define Q_IDXDIFF(q, idx) IDXDIFF((q)->pidx, (q)->idx, (q)->size)
#define R_IDXDIFF(q, idx) IDXDIFF((q)->cidx, (q)->idx, (q)->size)

/**
 * ring_tx_db - ring a Tx queue's doorbell
 * @adap: the adapter
 * @q: the Tx queue
 * @n: number of new descriptors to give to HW
 *
 * Ring the doorbel for a Tx queue.
 */
static inline void ring_tx_db(struct adapter *adap, struct sge_txq *q)
{
        int n = Q_IDXDIFF(q, dbidx);

        /*
         * Make sure that all writes to the TX Descriptors are committed
         * before we tell the hardware about them.
         */
        rte_wmb();

        /*
         * If we don't have access to the new User Doorbell (T5+), use the old
         * doorbell mechanism; otherwise use the new BAR2 mechanism.
         */
        if (unlikely(!q->bar2_addr)) {
                u32 val = V_PIDX(n);

                /*
                 * For T4 we need to participate in the Doorbell Recovery
                 * mechanism.
                 */
                if (!q->db_disabled)
                        t4_write_reg(adap, MYPF_REG(A_SGE_PF_KDOORBELL),
                                     V_QID(q->cntxt_id) | val);
                else
                        q->db_pidx_inc += n;
                q->db_pidx = q->pidx;
        } else {
                u32 val = V_PIDX_T5(n);

                /*
                 * T4 and later chips share the same PIDX field offset within
                 * the doorbell, but T5 and later shrank the field in order to
                 * gain a bit for Doorbell Priority.  The field was absurdly
                 * large in the first place (14 bits) so we just use the T5
                 * and later limits and warn if a Queue ID is too large.
                 */
                WARN_ON(val & F_DBPRIO);

                writel(val | V_QID(q->bar2_qid),
                       (void *)((uintptr_t)q->bar2_addr + SGE_UDB_KDOORBELL));

                /*
                 * This Write Memory Barrier will force the write to the User
                 * Doorbell area to be flushed.  This is needed to prevent
                 * writes on different CPUs for the same queue from hitting
                 * the adapter out of order.  This is required when some Work
                 * Requests take the Write Combine Gather Buffer path (user
                 * doorbell area offset [SGE_UDB_WCDOORBELL..+63]) and some
                 * take the traditional path where we simply increment the
                 * PIDX (User Doorbell area SGE_UDB_KDOORBELL) and have the
                 * hardware DMA read the actual Work Request.
                 */
                rte_wmb();
        }
        q->dbidx = q->pidx;
}

/*
 * Figure out what HW csum a packet wants and return the appropriate control
 * bits.
 */
static u64 hwcsum(enum chip_type chip, const struct rte_mbuf *m)
{
        int csum_type;

        if (m->ol_flags & PKT_TX_IP_CKSUM) {
                switch (m->ol_flags & PKT_TX_L4_MASK) {
                case PKT_TX_TCP_CKSUM:
                        csum_type = TX_CSUM_TCPIP;
                        break;
                case PKT_TX_UDP_CKSUM:
                        csum_type = TX_CSUM_UDPIP;
                        break;
                default:
                        goto nocsum;
                }
        } else {
                goto nocsum;
        }

        if (likely(csum_type >= TX_CSUM_TCPIP)) {
                int hdr_len = V_TXPKT_IPHDR_LEN(m->l3_len);
                int eth_hdr_len = m->l2_len;

                if (CHELSIO_CHIP_VERSION(chip) <= CHELSIO_T5)
                        hdr_len |= V_TXPKT_ETHHDR_LEN(eth_hdr_len);
                else
                        hdr_len |= V_T6_TXPKT_ETHHDR_LEN(eth_hdr_len);
                return V_TXPKT_CSUM_TYPE(csum_type) | hdr_len;
        }
nocsum:
        /*
         * unknown protocol, disable HW csum
         * and hope a bad packet is detected
         */
        return F_TXPKT_L4CSUM_DIS;
}

static inline void txq_advance(struct sge_txq *q, unsigned int n)
{
        q->in_use += n;
        q->pidx += n;
        if (q->pidx >= q->size)
                q->pidx -= q->size;
}

#define MAX_COALESCE_LEN 64000

static inline int wraps_around(struct sge_txq *q, int ndesc)
{
        return (q->pidx + ndesc) > q->size ? 1 : 0;
}

static void tx_timer_cb(void *data)
{
        struct adapter *adap = (struct adapter *)data;
        struct sge_eth_txq *txq = &adap->sge.ethtxq[0];
        int i;

        /* monitor any pending tx */
        for (i = 0; i < adap->sge.max_ethqsets; i++, txq++) {
                t4_os_lock(&txq->txq_lock);
                if (txq->q.coalesce.idx) {
                        if (txq->q.coalesce.idx == txq->q.last_coal_idx &&
                            txq->q.pidx == txq->q.last_pidx) {
                                ship_tx_pkt_coalesce_wr(adap, txq);
                        } else {
                                txq->q.last_coal_idx = txq->q.coalesce.idx;
                                txq->q.last_pidx = txq->q.pidx;
                        }
                }
                t4_os_unlock(&txq->txq_lock);
        }
        rte_eal_alarm_set(50, tx_timer_cb, (void *)adap);
}

/**
 * ship_tx_pkt_coalesce_wr - finalizes and ships a coalesce WR
 * @ adap: adapter structure
 * @txq: tx queue
 *
 * writes the different fields of the pkts WR and sends it.
 */
static inline void ship_tx_pkt_coalesce_wr(struct adapter *adap,
                                           struct sge_eth_txq *txq)
{
        u32 wr_mid;
        struct sge_txq *q = &txq->q;
        struct fw_eth_tx_pkts_wr *wr;
        unsigned int ndesc;

        /* fill the pkts WR header */
        wr = (void *)&q->desc[q->pidx];
        wr->op_pkd = htonl(V_FW_WR_OP(FW_ETH_TX_PKTS_WR));

        wr_mid = V_FW_WR_LEN16(DIV_ROUND_UP(q->coalesce.flits, 2));
        ndesc = flits_to_desc(q->coalesce.flits);
        wr->equiq_to_len16 = htonl(wr_mid);
        wr->plen = cpu_to_be16(q->coalesce.len);
        wr->npkt = q->coalesce.idx;
        wr->r3 = 0;
        wr->type = q->coalesce.type;

        /* zero out coalesce structure members */
        q->coalesce.idx = 0;
        q->coalesce.flits = 0;
        q->coalesce.len = 0;

        txq_advance(q, ndesc);
        txq->stats.coal_wr++;
        txq->stats.coal_pkts += wr->npkt;

        if (Q_IDXDIFF(q, equeidx) >= q->size / 2) {
                q->equeidx = q->pidx;
                wr_mid |= F_FW_WR_EQUEQ;
                wr->equiq_to_len16 = htonl(wr_mid);
        }
        ring_tx_db(adap, q);
}

/**
 * should_tx_packet_coalesce - decides wether to coalesce an mbuf or not
 * @txq: tx queue where the mbuf is sent
 * @mbuf: mbuf to be sent
 * @nflits: return value for number of flits needed
 * @adap: adapter structure
 *
 * This function decides if a packet should be coalesced or not.
 */
static inline int should_tx_packet_coalesce(struct sge_eth_txq *txq,
                                            struct rte_mbuf *mbuf,
                                            unsigned int *nflits,
                                            struct adapter *adap)
{
        struct sge_txq *q = &txq->q;
        unsigned int flits, ndesc;
        unsigned char type = 0;
        int credits, hw_cidx = ntohs(q->stat->cidx);
        int in_use = q->pidx - hw_cidx + flits_to_desc(q->coalesce.flits);

        /* use coal WR type 1 when no frags are present */
        type = (mbuf->nb_segs == 1) ? 1 : 0;

        if (in_use < 0)
                in_use += q->size;

        if (unlikely(type != q->coalesce.type && q->coalesce.idx))
                ship_tx_pkt_coalesce_wr(adap, txq);

        /* calculate the number of flits required for coalescing this packet
         * without the 2 flits of the WR header. These are added further down
         * if we are just starting in new PKTS WR. sgl_len doesn't account for
         * the possible 16 bytes alignment ULP TX commands so we do it here.
         */
        flits = (sgl_len(mbuf->nb_segs) + 1) & ~1U;
        if (type == 0)
                flits += (sizeof(struct ulp_txpkt) +
                          sizeof(struct ulptx_idata)) / sizeof(__be64);
        flits += sizeof(struct cpl_tx_pkt_core) / sizeof(__be64);
        *nflits = flits;

        /* If coalescing is on, the mbuf is added to a pkts WR */
        if (q->coalesce.idx) {
                ndesc = DIV_ROUND_UP(q->coalesce.flits + flits, 8);
                credits = txq_avail(q) - ndesc;

                /* If we are wrapping or this is last mbuf then, send the
                 * already coalesced mbufs and let the non-coalesce pass
                 * handle the mbuf.
                 */
                if (unlikely(credits < 0 || wraps_around(q, ndesc))) {
                        ship_tx_pkt_coalesce_wr(adap, txq);
                        return 0;
                }

                /* If the max coalesce len or the max WR len is reached
                 * ship the WR and keep coalescing on.
                 */
                if (unlikely((q->coalesce.len + mbuf->pkt_len >
                                                MAX_COALESCE_LEN) ||
                             (q->coalesce.flits + flits >
                              q->coalesce.max))) {
                        ship_tx_pkt_coalesce_wr(adap, txq);
                        goto new;
                }
                return 1;
        }

new:
        /* start a new pkts WR, the WR header is not filled below */
        flits += sizeof(struct fw_eth_tx_pkts_wr) / sizeof(__be64);
        ndesc = flits_to_desc(q->coalesce.flits + flits);
        credits = txq_avail(q) - ndesc;

        if (unlikely(credits < 0 || wraps_around(q, ndesc)))
                return 0;
        q->coalesce.flits += 2;
        q->coalesce.type = type;
        q->coalesce.ptr = (unsigned char *)&q->desc[q->pidx] +
                           2 * sizeof(__be64);
        return 1;
}

/**
 * tx_do_packet_coalesce - add an mbuf to a coalesce WR
 * @txq: sge_eth_txq used send the mbuf
 * @mbuf: mbuf to be sent
 * @flits: flits needed for this mbuf
 * @adap: adapter structure
 * @pi: port_info structure
 * @addr: mapped address of the mbuf
 *
 * Adds an mbuf to be sent as part of a coalesce WR by filling a
 * ulp_tx_pkt command, ulp_tx_sc_imm command, cpl message and
 * ulp_tx_sc_dsgl command.
 */
static inline int tx_do_packet_coalesce(struct sge_eth_txq *txq,
                                        struct rte_mbuf *mbuf,
                                        int flits, struct adapter *adap,
                                        const struct port_info *pi,
                                        dma_addr_t *addr)
{
        u64 cntrl, *end;
        struct sge_txq *q = &txq->q;
        struct ulp_txpkt *mc;
        struct ulptx_idata *sc_imm;
        struct cpl_tx_pkt_core *cpl;
        struct tx_sw_desc *sd;
        unsigned int idx = q->coalesce.idx, len = mbuf->pkt_len;

        if (q->coalesce.type == 0) {
                mc = (struct ulp_txpkt *)q->coalesce.ptr;
                mc->cmd_dest = htonl(V_ULPTX_CMD(4) | V_ULP_TXPKT_DEST(0) |
                                     V_ULP_TXPKT_FID(adap->sge.fw_evtq.cntxt_id) |
                                     F_ULP_TXPKT_RO);
                mc->len = htonl(DIV_ROUND_UP(flits, 2));
                sc_imm = (struct ulptx_idata *)(mc + 1);
                sc_imm->cmd_more = htonl(V_ULPTX_CMD(ULP_TX_SC_IMM) |
                                         F_ULP_TX_SC_MORE);
                sc_imm->len = htonl(sizeof(*cpl));
                end = (u64 *)mc + flits;
                cpl = (struct cpl_tx_pkt_core *)(sc_imm + 1);
        } else {
                end = (u64 *)q->coalesce.ptr + flits;
                cpl = (struct cpl_tx_pkt_core *)q->coalesce.ptr;
        }

        /* update coalesce structure for this txq */
        q->coalesce.flits += flits;
        q->coalesce.ptr += flits * sizeof(__be64);
        q->coalesce.len += mbuf->pkt_len;

        /* fill the cpl message, same as in t4_eth_xmit, this should be kept
         * similar to t4_eth_xmit
         */
        if (mbuf->ol_flags & PKT_TX_IP_CKSUM) {
                cntrl = hwcsum(adap->params.chip, mbuf) |
                               F_TXPKT_IPCSUM_DIS;
                txq->stats.tx_cso++;
        } else {
                cntrl = F_TXPKT_L4CSUM_DIS | F_TXPKT_IPCSUM_DIS;
        }

        if (mbuf->ol_flags & PKT_TX_VLAN_PKT) {
                txq->stats.vlan_ins++;
                cntrl |= F_TXPKT_VLAN_VLD | V_TXPKT_VLAN(mbuf->vlan_tci);
        }

        cpl->ctrl0 = htonl(V_TXPKT_OPCODE(CPL_TX_PKT_XT) |
                           V_TXPKT_INTF(pi->tx_chan) |
                           V_TXPKT_PF(adap->pf));
        cpl->pack = htons(0);
        cpl->len = htons(len);
        cpl->ctrl1 = cpu_to_be64(cntrl);
        write_sgl(mbuf, q, (struct ulptx_sgl *)(cpl + 1), end, 0,  addr);
        txq->stats.pkts++;
        txq->stats.tx_bytes += len;

        sd = &q->sdesc[q->pidx + (idx >> 1)];
        if (!(idx & 1)) {
                if (sd->coalesce.idx) {
                        int i;

                        for (i = 0; i < sd->coalesce.idx; i++) {
                                rte_pktmbuf_free(sd->coalesce.mbuf[i]);
                                sd->coalesce.mbuf[i] = NULL;
                        }
                }
        }

        /* store pointers to the mbuf and the sgl used in free_tx_desc.
         * each tx desc can hold two pointers corresponding to the value
         * of ETH_COALESCE_PKT_PER_DESC
         */
        sd->coalesce.mbuf[idx & 1] = mbuf;
        sd->coalesce.sgl[idx & 1] = (struct ulptx_sgl *)(cpl + 1);
        sd->coalesce.idx = (idx & 1) + 1;

        /* send the coaelsced work request if max reached */
        if (++q->coalesce.idx == ETH_COALESCE_PKT_NUM)
                ship_tx_pkt_coalesce_wr(adap, txq);
        return 0;
}

/**
 * t4_eth_xmit - add a packet to an Ethernet Tx queue
 * @txq: the egress queue
 * @mbuf: the packet
 *
 * Add a packet to an SGE Ethernet Tx queue.  Runs with softirqs disabled.
 */
int t4_eth_xmit(struct sge_eth_txq *txq, struct rte_mbuf *mbuf)
{
        const struct port_info *pi;
        struct cpl_tx_pkt_lso_core *lso;
        struct adapter *adap;
        struct rte_mbuf *m = mbuf;
        struct fw_eth_tx_pkt_wr *wr;
        struct cpl_tx_pkt_core *cpl;
        struct tx_sw_desc *d;
        dma_addr_t addr[m->nb_segs];
        unsigned int flits, ndesc, cflits;
        int l3hdr_len, l4hdr_len, eth_xtra_len;
        int len, last_desc;
        int credits;
        u32 wr_mid;
        u64 cntrl, *end;
        bool v6;
        u32 max_pkt_len = txq->eth_dev->data->dev_conf.rxmode.max_rx_pkt_len;

        /* Reject xmit if queue is stopped */
        if (unlikely(txq->flags & EQ_STOPPED))
                return -(EBUSY);

        /*
         * The chip min packet length is 10 octets but play safe and reject
         * anything shorter than an Ethernet header.
         */
        if (unlikely(m->pkt_len < ETHER_HDR_LEN)) {
out_free:
                rte_pktmbuf_free(m);
                return 0;
        }

        if ((!(m->ol_flags & PKT_TX_TCP_SEG)) &&
            (unlikely(m->pkt_len > max_pkt_len)))
                goto out_free;

        pi = (struct port_info *)txq->eth_dev->data->dev_private;
        adap = pi->adapter;

        cntrl = F_TXPKT_L4CSUM_DIS | F_TXPKT_IPCSUM_DIS;
        /* align the end of coalesce WR to a 512 byte boundary */
        txq->q.coalesce.max = (8 - (txq->q.pidx & 7)) * 8;

        if (!((m->ol_flags & PKT_TX_TCP_SEG) || (m->pkt_len > ETHER_MAX_LEN))) {
                if (should_tx_packet_coalesce(txq, mbuf, &cflits, adap)) {
                        if (unlikely(map_mbuf(mbuf, addr) < 0)) {
                                dev_warn(adap, "%s: mapping err for coalesce\n",
                                         __func__);
                                txq->stats.mapping_err++;
                                goto out_free;
                        }
                        rte_prefetch0((volatile void *)addr);
                        return tx_do_packet_coalesce(txq, mbuf, cflits, adap,
                                                     pi, addr);
                } else {
                        return -EBUSY;
                }
        }

        if (txq->q.coalesce.idx)
                ship_tx_pkt_coalesce_wr(adap, txq);

        flits = calc_tx_flits(m);
        ndesc = flits_to_desc(flits);
        credits = txq_avail(&txq->q) - ndesc;

        if (unlikely(credits < 0)) {
                dev_debug(adap, "%s: Tx ring %u full; credits = %d\n",
                          __func__, txq->q.cntxt_id, credits);
                return -EBUSY;
        }

        if (unlikely(map_mbuf(m, addr) < 0)) {
                txq->stats.mapping_err++;
                goto out_free;
        }

        wr_mid = V_FW_WR_LEN16(DIV_ROUND_UP(flits, 2));
        if (Q_IDXDIFF(&txq->q, equeidx)  >= 64) {
                txq->q.equeidx = txq->q.pidx;
                wr_mid |= F_FW_WR_EQUEQ;
        }

        wr = (void *)&txq->q.desc[txq->q.pidx];
        wr->equiq_to_len16 = htonl(wr_mid);
        wr->r3 = rte_cpu_to_be_64(0);
        end = (u64 *)wr + flits;

        len = 0;
        len += sizeof(*cpl);

        /* Coalescing skipped and we send through normal path */
        if (!(m->ol_flags & PKT_TX_TCP_SEG)) {
                wr->op_immdlen = htonl(V_FW_WR_OP(FW_ETH_TX_PKT_WR) |
                                       V_FW_WR_IMMDLEN(len));
                cpl = (void *)(wr + 1);
                if (m->ol_flags & PKT_TX_IP_CKSUM) {
                        cntrl = hwcsum(adap->params.chip, m) |
                                F_TXPKT_IPCSUM_DIS;
                        txq->stats.tx_cso++;
                }
        } else {
                lso = (void *)(wr + 1);
                v6 = (m->ol_flags & PKT_TX_IPV6) != 0;
                l3hdr_len = m->l3_len;
                l4hdr_len = m->l4_len;
                eth_xtra_len = m->l2_len - ETHER_HDR_LEN;
                len += sizeof(*lso);
                wr->op_immdlen = htonl(V_FW_WR_OP(FW_ETH_TX_PKT_WR) |
                                       V_FW_WR_IMMDLEN(len));
                lso->lso_ctrl = htonl(V_LSO_OPCODE(CPL_TX_PKT_LSO) |
                                      F_LSO_FIRST_SLICE | F_LSO_LAST_SLICE |
                                      V_LSO_IPV6(v6) |
                                      V_LSO_ETHHDR_LEN(eth_xtra_len / 4) |
                                      V_LSO_IPHDR_LEN(l3hdr_len / 4) |
                                      V_LSO_TCPHDR_LEN(l4hdr_len / 4));
                lso->ipid_ofst = htons(0);
                lso->mss = htons(m->tso_segsz);
                lso->seqno_offset = htonl(0);
                if (is_t4(adap->params.chip))
                        lso->len = htonl(m->pkt_len);
                else
                        lso->len = htonl(V_LSO_T5_XFER_SIZE(m->pkt_len));
                cpl = (void *)(lso + 1);
                cntrl = V_TXPKT_CSUM_TYPE(v6 ? TX_CSUM_TCPIP6 : TX_CSUM_TCPIP) |
                        V_TXPKT_IPHDR_LEN(l3hdr_len) |
                        V_TXPKT_ETHHDR_LEN(eth_xtra_len);
                txq->stats.tso++;
                txq->stats.tx_cso += m->tso_segsz;
        }

        if (m->ol_flags & PKT_TX_VLAN_PKT) {
                txq->stats.vlan_ins++;
                cntrl |= F_TXPKT_VLAN_VLD | V_TXPKT_VLAN(m->vlan_tci);
        }

        cpl->ctrl0 = htonl(V_TXPKT_OPCODE(CPL_TX_PKT_XT) |
                           V_TXPKT_INTF(pi->tx_chan) |
                           V_TXPKT_PF(adap->pf));
        cpl->pack = htons(0);
        cpl->len = htons(m->pkt_len);
        cpl->ctrl1 = cpu_to_be64(cntrl);

        txq->stats.pkts++;
        txq->stats.tx_bytes += m->pkt_len;
        last_desc = txq->q.pidx + ndesc - 1;
        if (last_desc >= (int)txq->q.size)
                last_desc -= txq->q.size;

        d = &txq->q.sdesc[last_desc];
        if (d->coalesce.idx) {
                int i;

                for (i = 0; i < d->coalesce.idx; i++) {
                        rte_pktmbuf_free(d->coalesce.mbuf[i]);
                        d->coalesce.mbuf[i] = NULL;
                }
                d->coalesce.idx = 0;
        }
        write_sgl(m, &txq->q, (struct ulptx_sgl *)(cpl + 1), end, 0,
                  addr);
        txq->q.sdesc[last_desc].mbuf = m;
        txq->q.sdesc[last_desc].sgl = (struct ulptx_sgl *)(cpl + 1);
        txq_advance(&txq->q, ndesc);
        ring_tx_db(adap, &txq->q);
        return 0;
}

/**
 * alloc_ring - allocate resources for an SGE descriptor ring
 * @dev: the PCI device's core device
 * @nelem: the number of descriptors
 * @elem_size: the size of each descriptor
 * @sw_size: the size of the SW state associated with each ring element
 * @phys: the physical address of the allocated ring
 * @metadata: address of the array holding the SW state for the ring
 * @stat_size: extra space in HW ring for status information
 * @node: preferred node for memory allocations
 *
 * Allocates resources for an SGE descriptor ring, such as Tx queues,
 * free buffer lists, or response queues.  Each SGE ring requires
 * space for its HW descriptors plus, optionally, space for the SW state
 * associated with each HW entry (the metadata).  The function returns
 * three values: the virtual address for the HW ring (the return value
 * of the function), the bus address of the HW ring, and the address
 * of the SW ring.
 */
static void *alloc_ring(size_t nelem, size_t elem_size,
                        size_t sw_size, dma_addr_t *phys, void *metadata,
                        size_t stat_size, __rte_unused uint16_t queue_id,
                        int socket_id, const char *z_name,
                        const char *z_name_sw)
{
        size_t len = CXGBE_MAX_RING_DESC_SIZE * elem_size + stat_size;
        const struct rte_memzone *tz;
        void *s = NULL;

        dev_debug(adapter, "%s: nelem = %zu; elem_size = %zu; sw_size = %zu; "
                  "stat_size = %zu; queue_id = %u; socket_id = %d; z_name = %s;"
                  " z_name_sw = %s\n", __func__, nelem, elem_size, sw_size,
                  stat_size, queue_id, socket_id, z_name, z_name_sw);

        tz = rte_memzone_lookup(z_name);
        if (tz) {
                dev_debug(adapter, "%s: tz exists...returning existing..\n",
                          __func__);
                goto alloc_sw_ring;
        }

        /*
         * Allocate TX/RX ring hardware descriptors. A memzone large enough to
         * handle the maximum ring size is allocated in order to allow for
         * resizing in later calls to the queue setup function.
         */
        tz = rte_memzone_reserve_aligned(z_name, len, socket_id, 0, 4096);
        if (!tz)
                return NULL;

alloc_sw_ring:
        memset(tz->addr, 0, len);
        if (sw_size) {
                s = rte_zmalloc_socket(z_name_sw, nelem * sw_size,
                                       RTE_CACHE_LINE_SIZE, socket_id);

                if (!s) {
                        dev_err(adapter, "%s: failed to get sw_ring memory\n",
                                __func__);
                        return NULL;
                }
        }
        if (metadata)
                *(void **)metadata = s;

        *phys = (uint64_t)tz->phys_addr;
        return tz->addr;
}

/**
 * t4_pktgl_to_mbuf_usembufs - build an mbuf from a packet gather list
 * @gl: the gather list
 *
 * Builds an mbuf from the given packet gather list.  Returns the mbuf or
 * %NULL if mbuf allocation failed.
 */
static struct rte_mbuf *t4_pktgl_to_mbuf_usembufs(const struct pkt_gl *gl)
{
        /*
         * If there's only one mbuf fragment, just return that.
         */
        if (likely(gl->nfrags == 1))
                return gl->mbufs[0];

        return NULL;
}

/**
 * t4_pktgl_to_mbuf - build an mbuf from a packet gather list
 * @gl: the gather list
 *
 * Builds an mbuf from the given packet gather list.  Returns the mbuf or
 * %NULL if mbuf allocation failed.
 */
static struct rte_mbuf *t4_pktgl_to_mbuf(const struct pkt_gl *gl)
{
        return t4_pktgl_to_mbuf_usembufs(gl);
}

#define RTE_MBUF_DATA_DMA_ADDR_DEFAULT(mb) \
        ((dma_addr_t) ((mb)->buf_physaddr + (mb)->data_off))

/**
 * t4_ethrx_handler - process an ingress ethernet packet
 * @q: the response queue that received the packet
 * @rsp: the response queue descriptor holding the RX_PKT message
 * @si: the gather list of packet fragments
 *
 * Process an ingress ethernet packet and deliver it to the stack.
 */
int t4_ethrx_handler(struct sge_rspq *q, const __be64 *rsp,
                     const struct pkt_gl *si)
{
        struct rte_mbuf *mbuf;
        const struct cpl_rx_pkt *pkt;
        const struct rss_header *rss_hdr;
        bool csum_ok;
        struct sge_eth_rxq *rxq = container_of(q, struct sge_eth_rxq, rspq);

        rss_hdr = (const void *)rsp;
        pkt = (const void *)&rsp[1];
        csum_ok = pkt->csum_calc && !pkt->err_vec;

        mbuf = t4_pktgl_to_mbuf(si);
        if (unlikely(!mbuf)) {
                rxq->stats.rx_drops++;
                return 0;
        }

        mbuf->port = pkt->iff;
        if (pkt->l2info & htonl(F_RXF_IP)) {
                mbuf->packet_type = RTE_PTYPE_L3_IPV4;
                if (unlikely(!csum_ok))
                        mbuf->ol_flags |= PKT_RX_IP_CKSUM_BAD;

                if ((pkt->l2info & htonl(F_RXF_UDP | F_RXF_TCP)) && !csum_ok)
                        mbuf->ol_flags |= PKT_RX_L4_CKSUM_BAD;
        } else if (pkt->l2info & htonl(F_RXF_IP6)) {
                mbuf->packet_type = RTE_PTYPE_L3_IPV6;
        }

        mbuf->port = pkt->iff;

        if (!rss_hdr->filter_tid && rss_hdr->hash_type) {
                mbuf->ol_flags |= PKT_RX_RSS_HASH;
                mbuf->hash.rss = ntohl(rss_hdr->hash_val);
        }

        if (pkt->vlan_ex) {
                mbuf->ol_flags |= PKT_RX_VLAN_PKT;
                mbuf->vlan_tci = ntohs(pkt->vlan);
        }
        rxq->stats.pkts++;
        rxq->stats.rx_bytes += mbuf->pkt_len;

        return 0;
}

/**
 * is_new_response - check if a response is newly written
 * @r: the response descriptor
 * @q: the response queue
 *
 * Returns true if a response descriptor contains a yet unprocessed
 * response.
 */
static inline bool is_new_response(const struct rsp_ctrl *r,
                                   const struct sge_rspq *q)
{
        return (r->u.type_gen >> S_RSPD_GEN) == q->gen;
}

#define CXGB4_MSG_AN ((void *)1)

/**
 * rspq_next - advance to the next entry in a response queue
 * @q: the queue
 *
 * Updates the state of a response queue to advance it to the next entry.
 */
static inline void rspq_next(struct sge_rspq *q)
{
        q->cur_desc = (const __be64 *)((const char *)q->cur_desc + q->iqe_len);
        if (unlikely(++q->cidx == q->size)) {
                q->cidx = 0;
                q->gen ^= 1;
                q->cur_desc = q->desc;
        }
}

/**
 * process_responses - process responses from an SGE response queue
 * @q: the ingress queue to process
 * @budget: how many responses can be processed in this round
 * @rx_pkts: mbuf to put the pkts
 *
 * Process responses from an SGE response queue up to the supplied budget.
 * Responses include received packets as well as control messages from FW
 * or HW.
 *
 * Additionally choose the interrupt holdoff time for the next interrupt
 * on this queue.  If the system is under memory shortage use a fairly
 * long delay to help recovery.
 */
static int process_responses(struct sge_rspq *q, int budget,
                             struct rte_mbuf **rx_pkts)
{
        int ret = 0, rsp_type;
        int budget_left = budget;
        const struct rsp_ctrl *rc;
        struct sge_eth_rxq *rxq = container_of(q, struct sge_eth_rxq, rspq);

        while (likely(budget_left)) {
                rc = (const struct rsp_ctrl *)
                     ((const char *)q->cur_desc + (q->iqe_len - sizeof(*rc)));

                if (!is_new_response(rc, q))
                        break;

                /*
                 * Ensure response has been read
                 */
                rmb();
                rsp_type = G_RSPD_TYPE(rc->u.type_gen);

                if (likely(rsp_type == X_RSPD_TYPE_FLBUF)) {
                        const struct rx_sw_desc *rsd =
                                                &rxq->fl.sdesc[rxq->fl.cidx];
                        const struct rss_header *rss_hdr =
                                                (const void *)q->cur_desc;
                        const struct cpl_rx_pkt *cpl =
                                                (const void *)&q->cur_desc[1];
                        bool csum_ok = cpl->csum_calc && !cpl->err_vec;
                        struct rte_mbuf *pkt, *npkt;
                        u32 len, bufsz;

                        len = ntohl(rc->pldbuflen_qid);
                        BUG_ON(!(len & F_RSPD_NEWBUF));
                        pkt = rsd->buf;
                        npkt = pkt;
                        len = G_RSPD_LEN(len);
                        pkt->pkt_len = len;

                        /* Chain mbufs into len if necessary */
                        while (len) {
                                struct rte_mbuf *new_pkt = rsd->buf;

                                bufsz = min(get_buf_size(q->adapter, rsd), len);
                                new_pkt->data_len = bufsz;
                                unmap_rx_buf(&rxq->fl);
                                len -= bufsz;
                                npkt->next = new_pkt;
                                npkt = new_pkt;
                                pkt->nb_segs++;
                                rsd = &rxq->fl.sdesc[rxq->fl.cidx];
                        }
                        npkt->next = NULL;
                        pkt->nb_segs--;

                        if (cpl->l2info & htonl(F_RXF_IP)) {
                                pkt->packet_type = RTE_PTYPE_L3_IPV4;
                                if (unlikely(!csum_ok))
                                        pkt->ol_flags |= PKT_RX_IP_CKSUM_BAD;

                                if ((cpl->l2info &
                                     htonl(F_RXF_UDP | F_RXF_TCP)) && !csum_ok)
                                        pkt->ol_flags |= PKT_RX_L4_CKSUM_BAD;
                        } else if (cpl->l2info & htonl(F_RXF_IP6)) {
                                pkt->packet_type = RTE_PTYPE_L3_IPV6;
                        }

                        if (!rss_hdr->filter_tid && rss_hdr->hash_type) {
                                pkt->ol_flags |= PKT_RX_RSS_HASH;
                                pkt->hash.rss = ntohl(rss_hdr->hash_val);
                        }

                        if (cpl->vlan_ex) {
                                pkt->ol_flags |= PKT_RX_VLAN_PKT;
                                pkt->vlan_tci = ntohs(cpl->vlan);
                        }
                        rxq->stats.pkts++;
                        rxq->stats.rx_bytes += pkt->pkt_len;
                        rx_pkts[budget - budget_left] = pkt;
                } else if (likely(rsp_type == X_RSPD_TYPE_CPL)) {
                        ret = q->handler(q, q->cur_desc, NULL);
                } else {
                        ret = q->handler(q, (const __be64 *)rc, CXGB4_MSG_AN);
                }

                if (unlikely(ret)) {
                        /* couldn't process descriptor, back off for recovery */
                        q->next_intr_params = V_QINTR_TIMER_IDX(NOMEM_TMR_IDX);
                        break;
                }

                rspq_next(q);
                budget_left--;

                if (R_IDXDIFF(q, gts_idx) >= 64) {
                        unsigned int cidx_inc = R_IDXDIFF(q, gts_idx);
                        unsigned int params;
                        u32 val;

                        if (fl_cap(&rxq->fl) - rxq->fl.avail >= 64)
                                __refill_fl(q->adapter, &rxq->fl);
                        params = V_QINTR_TIMER_IDX(X_TIMERREG_UPDATE_CIDX);
                        q->next_intr_params = params;
                        val = V_CIDXINC(cidx_inc) | V_SEINTARM(params);

                        if (unlikely(!q->bar2_addr))
                                t4_write_reg(q->adapter, MYPF_REG(A_SGE_PF_GTS),
                                             val |
                                             V_INGRESSQID((u32)q->cntxt_id));
                        else {
                                writel(val | V_INGRESSQID(q->bar2_qid),
                                       (void *)((uintptr_t)q->bar2_addr +
                                       SGE_UDB_GTS));
                                /*
                                 * This Write memory Barrier will force the
                                 * write to the User Doorbell area to be
                                 * flushed.
                                 */
                                wmb();
                        }
                        q->gts_idx = q->cidx;
                }
        }

        /*
         * If this is a Response Queue with an associated Free List and
         * there's room for another chunk of new Free List buffer pointers,
         * refill the Free List.
         */

        if (q->offset >= 0 && fl_cap(&rxq->fl) - rxq->fl.avail >= 64)
                __refill_fl(q->adapter, &rxq->fl);

        return budget - budget_left;
}

int cxgbe_poll(struct sge_rspq *q, struct rte_mbuf **rx_pkts,
               unsigned int budget, unsigned int *work_done)
{
        int err = 0;

        *work_done = process_responses(q, budget, rx_pkts);
        return err;
}

/**
 * bar2_address - return the BAR2 address for an SGE Queue's Registers
 * @adapter: the adapter
 * @qid: the SGE Queue ID
 * @qtype: the SGE Queue Type (Egress or Ingress)
 * @pbar2_qid: BAR2 Queue ID or 0 for Queue ID inferred SGE Queues
 *
 * Returns the BAR2 address for the SGE Queue Registers associated with
 * @qid.  If BAR2 SGE Registers aren't available, returns NULL.  Also
 * returns the BAR2 Queue ID to be used with writes to the BAR2 SGE
 * Queue Registers.  If the BAR2 Queue ID is 0, then "Inferred Queue ID"
 * Registers are supported (e.g. the Write Combining Doorbell Buffer).
 */
static void __iomem *bar2_address(struct adapter *adapter, unsigned int qid,
                                  enum t4_bar2_qtype qtype,
                                  unsigned int *pbar2_qid)
{
        u64 bar2_qoffset;
        int ret;

        ret = t4_bar2_sge_qregs(adapter, qid, qtype, &bar2_qoffset, pbar2_qid);
        if (ret)
                return NULL;

        return adapter->bar2 + bar2_qoffset;
}

int t4_sge_eth_rxq_start(struct adapter *adap, struct sge_rspq *rq)
{
        struct sge_eth_rxq *rxq = container_of(rq, struct sge_eth_rxq, rspq);
        unsigned int fl_id = rxq->fl.size ? rxq->fl.cntxt_id : 0xffff;

        return t4_iq_start_stop(adap, adap->mbox, true, adap->pf, 0,
                                rq->cntxt_id, fl_id, 0xffff);
}

int t4_sge_eth_rxq_stop(struct adapter *adap, struct sge_rspq *rq)
{
        struct sge_eth_rxq *rxq = container_of(rq, struct sge_eth_rxq, rspq);
        unsigned int fl_id = rxq->fl.size ? rxq->fl.cntxt_id : 0xffff;

        return t4_iq_start_stop(adap, adap->mbox, false, adap->pf, 0,
                                rq->cntxt_id, fl_id, 0xffff);
}

/*
 * @intr_idx: MSI/MSI-X vector if >=0, -(absolute qid + 1) if < 0
 * @cong: < 0 -> no congestion feedback, >= 0 -> congestion channel map
 */
int t4_sge_alloc_rxq(struct adapter *adap, struct sge_rspq *iq, bool fwevtq,
                     struct rte_eth_dev *eth_dev, int intr_idx,
                     struct sge_fl *fl, rspq_handler_t hnd, int cong,
                     struct rte_mempool *mp, int queue_id, int socket_id)
{
        int ret, flsz = 0;
        struct fw_iq_cmd c;
        struct sge *s = &adap->sge;
        struct port_info *pi = (struct port_info *)(eth_dev->data->dev_private);
        char z_name[RTE_MEMZONE_NAMESIZE];
        char z_name_sw[RTE_MEMZONE_NAMESIZE];
        unsigned int nb_refill;

        /* Size needs to be multiple of 16, including status entry. */
        iq->size = cxgbe_roundup(iq->size, 16);

        snprintf(z_name, sizeof(z_name), "%s_%s_%d_%d",
                 eth_dev->driver->pci_drv.name, fwevtq ? "fwq_ring" : "rx_ring",
                 eth_dev->data->port_id, queue_id);
        snprintf(z_name_sw, sizeof(z_name_sw), "%s_sw_ring", z_name);

        iq->desc = alloc_ring(iq->size, iq->iqe_len, 0, &iq->phys_addr, NULL, 0,
                              queue_id, socket_id, z_name, z_name_sw);
        if (!iq->desc)
                return -ENOMEM;

        memset(&c, 0, sizeof(c));
        c.op_to_vfn = htonl(V_FW_CMD_OP(FW_IQ_CMD) | F_FW_CMD_REQUEST |
                            F_FW_CMD_WRITE | F_FW_CMD_EXEC |
                            V_FW_IQ_CMD_PFN(adap->pf) | V_FW_IQ_CMD_VFN(0));
        c.alloc_to_len16 = htonl(F_FW_IQ_CMD_ALLOC | F_FW_IQ_CMD_IQSTART |
                                 (sizeof(c) / 16));
        c.type_to_iqandstindex =
                htonl(V_FW_IQ_CMD_TYPE(FW_IQ_TYPE_FL_INT_CAP) |
                      V_FW_IQ_CMD_IQASYNCH(fwevtq) |
                      V_FW_IQ_CMD_VIID(pi->viid) |
                      V_FW_IQ_CMD_IQANDST(intr_idx < 0) |
                      V_FW_IQ_CMD_IQANUD(X_UPDATEDELIVERY_INTERRUPT) |
                      V_FW_IQ_CMD_IQANDSTINDEX(intr_idx >= 0 ? intr_idx :
                                                               -intr_idx - 1));
        c.iqdroprss_to_iqesize =
                htons(V_FW_IQ_CMD_IQPCIECH(pi->tx_chan) |
                      F_FW_IQ_CMD_IQGTSMODE |
                      V_FW_IQ_CMD_IQINTCNTTHRESH(iq->pktcnt_idx) |
                      V_FW_IQ_CMD_IQESIZE(ilog2(iq->iqe_len) - 4));
        c.iqsize = htons(iq->size);
        c.iqaddr = cpu_to_be64(iq->phys_addr);
        if (cong >= 0)
                c.iqns_to_fl0congen = htonl(F_FW_IQ_CMD_IQFLINTCONGEN);

        if (fl) {
                struct sge_eth_rxq *rxq = container_of(fl, struct sge_eth_rxq,
                                                       fl);
                enum chip_type chip = (enum chip_type)CHELSIO_CHIP_VERSION(
                                adap->params.chip);

                /*
                 * Allocate the ring for the hardware free list (with space
                 * for its status page) along with the associated software
                 * descriptor ring.  The free list size needs to be a multiple
                 * of the Egress Queue Unit and at least 2 Egress Units larger
                 * than the SGE's Egress Congrestion Threshold
                 * (fl_starve_thres - 1).
                 */
                if (fl->size < s->fl_starve_thres - 1 + 2 * 8)
                        fl->size = s->fl_starve_thres - 1 + 2 * 8;
                fl->size = cxgbe_roundup(fl->size, 8);

                snprintf(z_name, sizeof(z_name), "%s_%s_%d_%d",
                         eth_dev->driver->pci_drv.name,
                         fwevtq ? "fwq_ring" : "fl_ring",
                         eth_dev->data->port_id, queue_id);
                snprintf(z_name_sw, sizeof(z_name_sw), "%s_sw_ring", z_name);

                fl->desc = alloc_ring(fl->size, sizeof(__be64),
                                      sizeof(struct rx_sw_desc),
                                      &fl->addr, &fl->sdesc, s->stat_len,
                                      queue_id, socket_id, z_name, z_name_sw);

                if (!fl->desc)
                        goto fl_nomem;

                flsz = fl->size / 8 + s->stat_len / sizeof(struct tx_desc);
                c.iqns_to_fl0congen |=
                        htonl(V_FW_IQ_CMD_FL0HOSTFCMODE(X_HOSTFCMODE_NONE) |
                              (unlikely(rxq->usembufs) ?
                               0 : F_FW_IQ_CMD_FL0PACKEN) |
                              F_FW_IQ_CMD_FL0FETCHRO | F_FW_IQ_CMD_FL0DATARO |
                              F_FW_IQ_CMD_FL0PADEN);
                if (cong >= 0)
                        c.iqns_to_fl0congen |=
                                htonl(V_FW_IQ_CMD_FL0CNGCHMAP(cong) |
                                      F_FW_IQ_CMD_FL0CONGCIF |
                                      F_FW_IQ_CMD_FL0CONGEN);

                /* In T6, for egress queue type FL there is internal overhead
                 * of 16B for header going into FLM module.
                 * Hence maximum allowed burst size will be 448 bytes.
                 */
                c.fl0dcaen_to_fl0cidxfthresh =
                        htons(V_FW_IQ_CMD_FL0FBMIN(X_FETCHBURSTMIN_128B) |
                              V_FW_IQ_CMD_FL0FBMAX((chip <= CHELSIO_T5) ?
                              X_FETCHBURSTMAX_512B : X_FETCHBURSTMAX_256B));
                c.fl0size = htons(flsz);
                c.fl0addr = cpu_to_be64(fl->addr);
        }

        ret = t4_wr_mbox(adap, adap->mbox, &c, sizeof(c), &c);
        if (ret)
                goto err;

        iq->cur_desc = iq->desc;
        iq->cidx = 0;
        iq->gts_idx = 0;
        iq->gen = 1;
        iq->next_intr_params = iq->intr_params;
        iq->cntxt_id = ntohs(c.iqid);
        iq->abs_id = ntohs(c.physiqid);
        iq->bar2_addr = bar2_address(adap, iq->cntxt_id, T4_BAR2_QTYPE_INGRESS,
                                     &iq->bar2_qid);
        iq->size--;                           /* subtract status entry */
        iq->eth_dev = eth_dev;
        iq->handler = hnd;
        iq->port_id = pi->port_id;
        iq->mb_pool = mp;

        /* set offset to -1 to distinguish ingress queues without FL */
        iq->offset = fl ? 0 : -1;

        if (fl) {
                fl->cntxt_id = ntohs(c.fl0id);
                fl->avail = 0;
                fl->pend_cred = 0;
                fl->pidx = 0;
                fl->cidx = 0;
                fl->alloc_failed = 0;

                /*
                 * Note, we must initialize the BAR2 Free List User Doorbell
                 * information before refilling the Free List!
                 */
                fl->bar2_addr = bar2_address(adap, fl->cntxt_id,
                                             T4_BAR2_QTYPE_EGRESS,
                                             &fl->bar2_qid);

                nb_refill = refill_fl(adap, fl, fl_cap(fl));
                if (nb_refill != fl_cap(fl)) {
                        ret = -ENOMEM;
                        dev_err(adap, "%s: mbuf alloc failed with error: %d\n",
                                __func__, ret);
                        goto refill_fl_err;
                }
        }

        /*
         * For T5 and later we attempt to set up the Congestion Manager values
         * of the new RX Ethernet Queue.  This should really be handled by
         * firmware because it's more complex than any host driver wants to
         * get involved with and it's different per chip and this is almost
         * certainly wrong.  Formware would be wrong as well, but it would be
         * a lot easier to fix in one place ...  For now we do something very
         * simple (and hopefully less wrong).
         */
        if (!is_t4(adap->params.chip) && cong >= 0) {
                u32 param, val;
                int i;

                param = (V_FW_PARAMS_MNEM(FW_PARAMS_MNEM_DMAQ) |
                         V_FW_PARAMS_PARAM_X(FW_PARAMS_PARAM_DMAQ_CONM_CTXT) |
                         V_FW_PARAMS_PARAM_YZ(iq->cntxt_id));
                if (cong == 0) {
                        val = V_CONMCTXT_CNGTPMODE(X_CONMCTXT_CNGTPMODE_QUEUE);
                } else {
                        val = V_CONMCTXT_CNGTPMODE(
                                        X_CONMCTXT_CNGTPMODE_CHANNEL);
                        for (i = 0; i < 4; i++) {
                                if (cong & (1 << i))
                                        val |= V_CONMCTXT_CNGCHMAP(1 <<
                                                                   (i << 2));
                        }
                }
                ret = t4_set_params(adap, adap->mbox, adap->pf, 0, 1,
                                    &param, &val);
                if (ret)
                        dev_warn(adap->pdev_dev, "Failed to set Congestion Manager Context for Ingress Queue %d: %d\n",
                                 iq->cntxt_id, -ret);
        }

        return 0;

refill_fl_err:
        t4_iq_free(adap, adap->mbox, adap->pf, 0, FW_IQ_TYPE_FL_INT_CAP,
                   iq->cntxt_id, fl ? fl->cntxt_id : 0xffff, 0xffff);
fl_nomem:
        ret = -ENOMEM;
err:
        iq->cntxt_id = 0;
        iq->abs_id = 0;
        if (iq->desc)
                iq->desc = NULL;

        if (fl && fl->desc) {
                rte_free(fl->sdesc);
                fl->cntxt_id = 0;
                fl->sdesc = NULL;
                fl->desc = NULL;
        }
        return ret;
}

static void init_txq(struct adapter *adap, struct sge_txq *q, unsigned int id)
{
        q->cntxt_id = id;
        q->bar2_addr = bar2_address(adap, q->cntxt_id, T4_BAR2_QTYPE_EGRESS,
                                    &q->bar2_qid);
        q->cidx = 0;
        q->pidx = 0;
        q->dbidx = 0;
        q->in_use = 0;
        q->equeidx = 0;
        q->coalesce.idx = 0;
        q->coalesce.len = 0;
        q->coalesce.flits = 0;
        q->last_coal_idx = 0;
        q->last_pidx = 0;
        q->stat = (void *)&q->desc[q->size];
}

int t4_sge_eth_txq_start(struct sge_eth_txq *txq)
{
        /*
         *  TODO: For flow-control, queue may be stopped waiting to reclaim
         *  credits.
         *  Ensure queue is in EQ_STOPPED state before starting it.
         */
        if (!(txq->flags & EQ_STOPPED))
                return -(EBUSY);

        txq->flags &= ~EQ_STOPPED;

        return 0;
}

int t4_sge_eth_txq_stop(struct sge_eth_txq *txq)
{
        txq->flags |= EQ_STOPPED;

        return 0;
}

int t4_sge_alloc_eth_txq(struct adapter *adap, struct sge_eth_txq *txq,
                         struct rte_eth_dev *eth_dev, uint16_t queue_id,
                         unsigned int iqid, int socket_id)
{
        int ret, nentries;
        struct fw_eq_eth_cmd c;
        struct sge *s = &adap->sge;
        struct port_info *pi = (struct port_info *)(eth_dev->data->dev_private);
        char z_name[RTE_MEMZONE_NAMESIZE];
        char z_name_sw[RTE_MEMZONE_NAMESIZE];

        /* Add status entries */
        nentries = txq->q.size + s->stat_len / sizeof(struct tx_desc);

        snprintf(z_name, sizeof(z_name), "%s_%s_%d_%d",
                 eth_dev->driver->pci_drv.name, "tx_ring",
                 eth_dev->data->port_id, queue_id);
        snprintf(z_name_sw, sizeof(z_name_sw), "%s_sw_ring", z_name);

        txq->q.desc = alloc_ring(txq->q.size, sizeof(struct tx_desc),
                                 sizeof(struct tx_sw_desc), &txq->q.phys_addr,
                                 &txq->q.sdesc, s->stat_len, queue_id,
                                 socket_id, z_name, z_name_sw);
        if (!txq->q.desc)
                return -ENOMEM;

        memset(&c, 0, sizeof(c));
        c.op_to_vfn = htonl(V_FW_CMD_OP(FW_EQ_ETH_CMD) | F_FW_CMD_REQUEST |
                            F_FW_CMD_WRITE | F_FW_CMD_EXEC |
                            V_FW_EQ_ETH_CMD_PFN(adap->pf) |
                            V_FW_EQ_ETH_CMD_VFN(0));
        c.alloc_to_len16 = htonl(F_FW_EQ_ETH_CMD_ALLOC |
                                 F_FW_EQ_ETH_CMD_EQSTART | (sizeof(c) / 16));
        c.autoequiqe_to_viid = htonl(F_FW_EQ_ETH_CMD_AUTOEQUEQE |
                                     V_FW_EQ_ETH_CMD_VIID(pi->viid));
        c.fetchszm_to_iqid =
                htonl(V_FW_EQ_ETH_CMD_HOSTFCMODE(X_HOSTFCMODE_NONE) |
                      V_FW_EQ_ETH_CMD_PCIECHN(pi->tx_chan) |
                      F_FW_EQ_ETH_CMD_FETCHRO | V_FW_EQ_ETH_CMD_IQID(iqid));
        c.dcaen_to_eqsize =
                htonl(V_FW_EQ_ETH_CMD_FBMIN(X_FETCHBURSTMIN_64B) |
                      V_FW_EQ_ETH_CMD_FBMAX(X_FETCHBURSTMAX_512B) |
                      V_FW_EQ_ETH_CMD_EQSIZE(nentries));
        c.eqaddr = rte_cpu_to_be_64(txq->q.phys_addr);

        ret = t4_wr_mbox(adap, adap->mbox, &c, sizeof(c), &c);
        if (ret) {
                rte_free(txq->q.sdesc);
                txq->q.sdesc = NULL;
                txq->q.desc = NULL;
                return ret;
        }

        init_txq(adap, &txq->q, G_FW_EQ_ETH_CMD_EQID(ntohl(c.eqid_pkd)));
        txq->stats.tso = 0;
        txq->stats.pkts = 0;
        txq->stats.tx_cso = 0;
        txq->stats.coal_wr = 0;
        txq->stats.vlan_ins = 0;
        txq->stats.tx_bytes = 0;
        txq->stats.coal_pkts = 0;
        txq->stats.mapping_err = 0;
        txq->flags |= EQ_STOPPED;
        txq->eth_dev = eth_dev;
        t4_os_lock_init(&txq->txq_lock);
        return 0;
}

static void free_txq(struct sge_txq *q)
{
        q->cntxt_id = 0;
        q->sdesc = NULL;
        q->desc = NULL;
}

static void free_rspq_fl(struct adapter *adap, struct sge_rspq *rq,
                         struct sge_fl *fl)
{
        unsigned int fl_id = fl ? fl->cntxt_id : 0xffff;

        t4_iq_free(adap, adap->mbox, adap->pf, 0, FW_IQ_TYPE_FL_INT_CAP,
                   rq->cntxt_id, fl_id, 0xffff);
        rq->cntxt_id = 0;
        rq->abs_id = 0;
        rq->desc = NULL;

        if (fl) {
                free_rx_bufs(fl, fl->avail);
                rte_free(fl->sdesc);
                fl->sdesc = NULL;
                fl->cntxt_id = 0;
                fl->desc = NULL;
        }
}

/*
 * Clear all queues of the port
 *
 * Note:  This function must only be called after rx and tx path
 * of the port have been disabled.
 */
void t4_sge_eth_clear_queues(struct port_info *pi)
{
        int i;
        struct adapter *adap = pi->adapter;
        struct sge_eth_rxq *rxq = &adap->sge.ethrxq[pi->first_qset];
        struct sge_eth_txq *txq = &adap->sge.ethtxq[pi->first_qset];

        for (i = 0; i < pi->n_rx_qsets; i++, rxq++) {
                if (rxq->rspq.desc)
                        t4_sge_eth_rxq_stop(adap, &rxq->rspq);
        }
        for (i = 0; i < pi->n_tx_qsets; i++, txq++) {
                if (txq->q.desc) {
                        struct sge_txq *q = &txq->q;

                        t4_sge_eth_txq_stop(txq);
                        reclaim_completed_tx(q);
                        free_tx_desc(q, q->size);
                        q->equeidx = q->pidx;
                }
        }
}

void t4_sge_eth_rxq_release(struct adapter *adap, struct sge_eth_rxq *rxq)
{
        if (rxq->rspq.desc) {
                t4_sge_eth_rxq_stop(adap, &rxq->rspq);
                free_rspq_fl(adap, &rxq->rspq, rxq->fl.size ? &rxq->fl : NULL);
        }
}

void t4_sge_eth_txq_release(struct adapter *adap, struct sge_eth_txq *txq)
{
        if (txq->q.desc) {
                t4_sge_eth_txq_stop(txq);
                reclaim_completed_tx(&txq->q);
                t4_eth_eq_free(adap, adap->mbox, adap->pf, 0, txq->q.cntxt_id);
                free_tx_desc(&txq->q, txq->q.size);
                rte_free(txq->q.sdesc);
                free_txq(&txq->q);
        }
}

void t4_sge_tx_monitor_start(struct adapter *adap)
{
        rte_eal_alarm_set(50, tx_timer_cb, (void *)adap);
}

void t4_sge_tx_monitor_stop(struct adapter *adap)
{
        rte_eal_alarm_cancel(tx_timer_cb, (void *)adap);
}

/**
 * t4_free_sge_resources - free SGE resources
 * @adap: the adapter
 *
 * Frees resources used by the SGE queue sets.
 */
void t4_free_sge_resources(struct adapter *adap)
{
        int i;
        struct sge_eth_rxq *rxq = &adap->sge.ethrxq[0];
        struct sge_eth_txq *txq = &adap->sge.ethtxq[0];

        /* clean up Ethernet Tx/Rx queues */
        for (i = 0; i < adap->sge.max_ethqsets; i++, rxq++, txq++) {
                /* Free only the queues allocated */
                if (rxq->rspq.desc) {
                        t4_sge_eth_rxq_release(adap, rxq);
                        rxq->rspq.eth_dev = NULL;
                }
                if (txq->q.desc) {
                        t4_sge_eth_txq_release(adap, txq);
                        txq->eth_dev = NULL;
                }
        }

        if (adap->sge.fw_evtq.desc)
                free_rspq_fl(adap, &adap->sge.fw_evtq, NULL);
}

/**
 * t4_sge_init - initialize SGE
 * @adap: the adapter
 *
 * Performs SGE initialization needed every time after a chip reset.
 * We do not initialize any of the queues here, instead the driver
 * top-level must request those individually.
 *
 * Called in two different modes:
 *
 *  1. Perform actual hardware initialization and record hard-coded
 *     parameters which were used.  This gets used when we're the
 *     Master PF and the Firmware Configuration File support didn't
 *     work for some reason.
 *
 *  2. We're not the Master PF or initialization was performed with
 *     a Firmware Configuration File.  In this case we need to grab
 *     any of the SGE operating parameters that we need to have in
 *     order to do our job and make sure we can live with them ...
 */
static int t4_sge_init_soft(struct adapter *adap)
{
        struct sge *s = &adap->sge;
        u32 fl_small_pg, fl_large_pg, fl_small_mtu, fl_large_mtu;
        u32 timer_value_0_and_1, timer_value_2_and_3, timer_value_4_and_5;
        u32 ingress_rx_threshold;

        /*
         * Verify that CPL messages are going to the Ingress Queue for
         * process_responses() and that only packet data is going to the
         * Free Lists.
         */
        if ((t4_read_reg(adap, A_SGE_CONTROL) & F_RXPKTCPLMODE) !=
            V_RXPKTCPLMODE(X_RXPKTCPLMODE_SPLIT)) {
                dev_err(adap, "bad SGE CPL MODE\n");
                return -EINVAL;
        }

        /*
         * Validate the Host Buffer Register Array indices that we want to
         * use ...
         *
         * XXX Note that we should really read through the Host Buffer Size
         * XXX register array and find the indices of the Buffer Sizes which
         * XXX meet our needs!
         */
#define READ_FL_BUF(x) \
        t4_read_reg(adap, A_SGE_FL_BUFFER_SIZE0 + (x) * sizeof(u32))

        fl_small_pg = READ_FL_BUF(RX_SMALL_PG_BUF);
        fl_large_pg = READ_FL_BUF(RX_LARGE_PG_BUF);
        fl_small_mtu = READ_FL_BUF(RX_SMALL_MTU_BUF);
        fl_large_mtu = READ_FL_BUF(RX_LARGE_MTU_BUF);

        /*
         * We only bother using the Large Page logic if the Large Page Buffer
         * is larger than our Page Size Buffer.
         */
        if (fl_large_pg <= fl_small_pg)
                fl_large_pg = 0;

#undef READ_FL_BUF

        /*
         * The Page Size Buffer must be exactly equal to our Page Size and the
         * Large Page Size Buffer should be 0 (per above) or a power of 2.
         */
        if (fl_small_pg != CXGBE_PAGE_SIZE ||
            (fl_large_pg & (fl_large_pg - 1)) != 0) {
                dev_err(adap, "bad SGE FL page buffer sizes [%d, %d]\n",
                        fl_small_pg, fl_large_pg);
                return -EINVAL;
        }
        if (fl_large_pg)
                s->fl_pg_order = ilog2(fl_large_pg) - PAGE_SHIFT;

        if (adap->use_unpacked_mode) {
                int err = 0;

                if (fl_small_mtu < FL_MTU_SMALL_BUFSIZE(adap)) {
                        dev_err(adap, "bad SGE FL small MTU %d\n",
                                fl_small_mtu);
                        err = -EINVAL;
                }
                if (fl_large_mtu < FL_MTU_LARGE_BUFSIZE(adap)) {
                        dev_err(adap, "bad SGE FL large MTU %d\n",
                                fl_large_mtu);
                        err = -EINVAL;
                }
                if (err)
                        return err;
        }

        /*
         * Retrieve our RX interrupt holdoff timer values and counter
         * threshold values from the SGE parameters.
         */
        timer_value_0_and_1 = t4_read_reg(adap, A_SGE_TIMER_VALUE_0_AND_1);
        timer_value_2_and_3 = t4_read_reg(adap, A_SGE_TIMER_VALUE_2_AND_3);
        timer_value_4_and_5 = t4_read_reg(adap, A_SGE_TIMER_VALUE_4_AND_5);
        s->timer_val[0] = core_ticks_to_us(adap,
                                           G_TIMERVALUE0(timer_value_0_and_1));
        s->timer_val[1] = core_ticks_to_us(adap,
                                           G_TIMERVALUE1(timer_value_0_and_1));
        s->timer_val[2] = core_ticks_to_us(adap,
                                           G_TIMERVALUE2(timer_value_2_and_3));
        s->timer_val[3] = core_ticks_to_us(adap,
                                           G_TIMERVALUE3(timer_value_2_and_3));
        s->timer_val[4] = core_ticks_to_us(adap,
                                           G_TIMERVALUE4(timer_value_4_and_5));
        s->timer_val[5] = core_ticks_to_us(adap,
                                           G_TIMERVALUE5(timer_value_4_and_5));

        ingress_rx_threshold = t4_read_reg(adap, A_SGE_INGRESS_RX_THRESHOLD);
        s->counter_val[0] = G_THRESHOLD_0(ingress_rx_threshold);
        s->counter_val[1] = G_THRESHOLD_1(ingress_rx_threshold);
        s->counter_val[2] = G_THRESHOLD_2(ingress_rx_threshold);
        s->counter_val[3] = G_THRESHOLD_3(ingress_rx_threshold);

        return 0;
}

int t4_sge_init(struct adapter *adap)
{
        struct sge *s = &adap->sge;
        u32 sge_control, sge_control2, sge_conm_ctrl;
        unsigned int ingpadboundary, ingpackboundary;
        int ret, egress_threshold;

        /*
         * Ingress Padding Boundary and Egress Status Page Size are set up by
         * t4_fixup_host_params().
         */
        sge_control = t4_read_reg(adap, A_SGE_CONTROL);
        s->pktshift = G_PKTSHIFT(sge_control);
        s->stat_len = (sge_control & F_EGRSTATUSPAGESIZE) ? 128 : 64;

        /*
         * T4 uses a single control field to specify both the PCIe Padding and
         * Packing Boundary.  T5 introduced the ability to specify these
         * separately.  The actual Ingress Packet Data alignment boundary
         * within Packed Buffer Mode is the maximum of these two
         * specifications.
         */
        ingpadboundary = 1 << (G_INGPADBOUNDARY(sge_control) +
                         X_INGPADBOUNDARY_SHIFT);
        s->fl_align = ingpadboundary;

        if (!is_t4(adap->params.chip) && !adap->use_unpacked_mode) {
                /*
                 * T5 has a weird interpretation of one of the PCIe Packing
                 * Boundary values.  No idea why ...
                 */
                sge_control2 = t4_read_reg(adap, A_SGE_CONTROL2);
                ingpackboundary = G_INGPACKBOUNDARY(sge_control2);
                if (ingpackboundary == X_INGPACKBOUNDARY_16B)
                        ingpackboundary = 16;
                else
                        ingpackboundary = 1 << (ingpackboundary +
                                          X_INGPACKBOUNDARY_SHIFT);

                s->fl_align = max(ingpadboundary, ingpackboundary);
        }

        ret = t4_sge_init_soft(adap);
        if (ret < 0) {
                dev_err(adap, "%s: t4_sge_init_soft failed, error %d\n",
                        __func__, -ret);
                return ret;
        }

        /*
         * A FL with <= fl_starve_thres buffers is starving and a periodic
         * timer will attempt to refill it.  This needs to be larger than the
         * SGE's Egress Congestion Threshold.  If it isn't, then we can get
         * stuck waiting for new packets while the SGE is waiting for us to
         * give it more Free List entries.  (Note that the SGE's Egress
         * Congestion Threshold is in units of 2 Free List pointers.)  For T4,
         * there was only a single field to control this.  For T5 there's the
         * original field which now only applies to Unpacked Mode Free List
         * buffers and a new field which only applies to Packed Mode Free List
         * buffers.
         */
        sge_conm_ctrl = t4_read_reg(adap, A_SGE_CONM_CTRL);
        if (is_t4(adap->params.chip) || adap->use_unpacked_mode)
                egress_threshold = G_EGRTHRESHOLD(sge_conm_ctrl);
        else
                egress_threshold = G_EGRTHRESHOLDPACKING(sge_conm_ctrl);
        s->fl_starve_thres = 2 * egress_threshold + 1;

        return 0;
}