[PATCH] chelsio: statistics improvement

[linux-2.6/s3c2410-cpufreq.git] / drivers / net / chelsio / sge.c

/*****************************************************************************
 *                                                                           *
 * File: sge.c                                                               *
 * $Revision: 1.26 $                                                         *
 * $Date: 2005/06/21 18:29:48 $                                              *
 * Description:                                                              *
 *  DMA engine.                                                              *
 *  part of the Chelsio 10Gb Ethernet Driver.                                *
 *                                                                           *
 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the GNU General Public License, version 2, as       *
 * published by the Free Software Foundation.                                *
 *                                                                           *
 * You should have received a copy of the GNU General Public License along   *
 * with this program; if not, write to the Free Software Foundation, Inc.,   *
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.                 *
 *                                                                           *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED    *
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF      *
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.                     *
 *                                                                           *
 * http://www.chelsio.com                                                    *
 *                                                                           *
 * Copyright (c) 2003 - 2005 Chelsio Communications, Inc.                    *
 * All rights reserved.                                                      *
 *                                                                           *
 * Maintainers: maintainers@chelsio.com                                      *
 *                                                                           *
 * Authors: Dimitrios Michailidis   <dm@chelsio.com>                         *
 *          Tina Yang               <tainay@chelsio.com>                     *
 *          Felix Marti             <felix@chelsio.com>                      *
 *          Scott Bardone           <sbardone@chelsio.com>                   *
 *          Kurt Ottaway            <kottaway@chelsio.com>                   *
 *          Frank DiMambro          <frank@chelsio.com>                      *
 *                                                                           *
 * History:                                                                  *
 *                                                                           *
 ****************************************************************************/

#include "common.h"

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/ktime.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/tcp.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/if_arp.h>

#include "cpl5_cmd.h"
#include "sge.h"
#include "regs.h"
#include "espi.h"

/* This belongs in if_ether.h */
#define ETH_P_CPL5 0xf

#define SGE_CMDQ_N              2
#define SGE_FREELQ_N            2
#define SGE_CMDQ0_E_N           1024
#define SGE_CMDQ1_E_N           128
#define SGE_FREEL_SIZE          4096
#define SGE_JUMBO_FREEL_SIZE    512
#define SGE_FREEL_REFILL_THRESH 16
#define SGE_RESPQ_E_N           1024
#define SGE_INTRTIMER_NRES      1000
#define SGE_RX_COPY_THRES       256
#define SGE_RX_SM_BUF_SIZE      1536
#define SGE_TX_DESC_MAX_PLEN    16384

# define SGE_RX_DROP_THRES 2

#define SGE_RESPQ_REPLENISH_THRES (SGE_RESPQ_E_N / 4)

/*
 * Period of the TX buffer reclaim timer.  This timer does not need to run
 * frequently as TX buffers are usually reclaimed by new TX packets.
 */
#define TX_RECLAIM_PERIOD (HZ / 4)

#ifndef NET_IP_ALIGN
# define NET_IP_ALIGN 2
#endif

#define M_CMD_LEN       0x7fffffff
#define V_CMD_LEN(v)    (v)
#define G_CMD_LEN(v)    ((v) & M_CMD_LEN)
#define V_CMD_GEN1(v)   ((v) << 31)
#define V_CMD_GEN2(v)   (v)
#define F_CMD_DATAVALID (1 << 1)
#define F_CMD_SOP       (1 << 2)
#define V_CMD_EOP(v)    ((v) << 3)

/*
 * Command queue, receive buffer list, and response queue descriptors.
 */
#if defined(__BIG_ENDIAN_BITFIELD)
struct cmdQ_e {
        u32 addr_lo;
        u32 len_gen;
        u32 flags;
        u32 addr_hi;
};

struct freelQ_e {
        u32 addr_lo;
        u32 len_gen;
        u32 gen2;
        u32 addr_hi;
};

struct respQ_e {
        u32 Qsleeping           : 4;
        u32 Cmdq1CreditReturn   : 5;
        u32 Cmdq1DmaComplete    : 5;
        u32 Cmdq0CreditReturn   : 5;
        u32 Cmdq0DmaComplete    : 5;
        u32 FreelistQid         : 2;
        u32 CreditValid         : 1;
        u32 DataValid           : 1;
        u32 Offload             : 1;
        u32 Eop                 : 1;
        u32 Sop                 : 1;
        u32 GenerationBit       : 1;
        u32 BufferLength;
};
#elif defined(__LITTLE_ENDIAN_BITFIELD)
struct cmdQ_e {
        u32 len_gen;
        u32 addr_lo;
        u32 addr_hi;
        u32 flags;
};

struct freelQ_e {
        u32 len_gen;
        u32 addr_lo;
        u32 addr_hi;
        u32 gen2;
};

struct respQ_e {
        u32 BufferLength;
        u32 GenerationBit       : 1;
        u32 Sop                 : 1;
        u32 Eop                 : 1;
        u32 Offload             : 1;
        u32 DataValid           : 1;
        u32 CreditValid         : 1;
        u32 FreelistQid         : 2;
        u32 Cmdq0DmaComplete    : 5;
        u32 Cmdq0CreditReturn   : 5;
        u32 Cmdq1DmaComplete    : 5;
        u32 Cmdq1CreditReturn   : 5;
        u32 Qsleeping           : 4;
} ;
#endif

/*
 * SW Context Command and Freelist Queue Descriptors
 */
struct cmdQ_ce {
        struct sk_buff *skb;
        DECLARE_PCI_UNMAP_ADDR(dma_addr);
        DECLARE_PCI_UNMAP_LEN(dma_len);
};

struct freelQ_ce {
        struct sk_buff *skb;
        DECLARE_PCI_UNMAP_ADDR(dma_addr);
        DECLARE_PCI_UNMAP_LEN(dma_len);
};

/*
 * SW command, freelist and response rings
 */
struct cmdQ {
        unsigned long   status;         /* HW DMA fetch status */
        unsigned int    in_use;         /* # of in-use command descriptors */
        unsigned int    size;           /* # of descriptors */
        unsigned int    processed;      /* total # of descs HW has processed */
        unsigned int    cleaned;        /* total # of descs SW has reclaimed */
        unsigned int    stop_thres;     /* SW TX queue suspend threshold */
        u16             pidx;           /* producer index (SW) */
        u16             cidx;           /* consumer index (HW) */
        u8              genbit;         /* current generation (=valid) bit */
        u8              sop;            /* is next entry start of packet? */
        struct cmdQ_e  *entries;        /* HW command descriptor Q */
        struct cmdQ_ce *centries;       /* SW command context descriptor Q */
        dma_addr_t      dma_addr;       /* DMA addr HW command descriptor Q */
        spinlock_t      lock;           /* Lock to protect cmdQ enqueuing */
};

struct freelQ {
        unsigned int    credits;        /* # of available RX buffers */
        unsigned int    size;           /* free list capacity */
        u16             pidx;           /* producer index (SW) */
        u16             cidx;           /* consumer index (HW) */
        u16             rx_buffer_size; /* Buffer size on this free list */
        u16             dma_offset;     /* DMA offset to align IP headers */
        u16             recycleq_idx;   /* skb recycle q to use */
        u8              genbit;         /* current generation (=valid) bit */
        struct freelQ_e *entries;       /* HW freelist descriptor Q */
        struct freelQ_ce *centries;     /* SW freelist context descriptor Q */
        dma_addr_t      dma_addr;       /* DMA addr HW freelist descriptor Q */
};

struct respQ {
        unsigned int    credits;        /* credits to be returned to SGE */
        unsigned int    size;           /* # of response Q descriptors */
        u16             cidx;           /* consumer index (SW) */
        u8              genbit;         /* current generation(=valid) bit */
        struct respQ_e *entries;        /* HW response descriptor Q */
        dma_addr_t      dma_addr;       /* DMA addr HW response descriptor Q */
};

/* Bit flags for cmdQ.status */
enum {
        CMDQ_STAT_RUNNING = 1,          /* fetch engine is running */
        CMDQ_STAT_LAST_PKT_DB = 2       /* last packet rung the doorbell */
};

/* T204 TX SW scheduler */

/* Per T204 TX port */
struct sched_port {
        unsigned int    avail;          /* available bits - quota */
        unsigned int    drain_bits_per_1024ns; /* drain rate */
        unsigned int    speed;          /* drain rate, mbps */
        unsigned int    mtu;            /* mtu size */
        struct sk_buff_head skbq;       /* pending skbs */
};

/* Per T204 device */
struct sched {
        ktime_t         last_updated;   /* last time quotas were computed */
        unsigned int    max_avail;      /* max bits to be sent to any port */
        unsigned int    port;           /* port index (round robin ports) */
        unsigned int    num;            /* num skbs in per port queues */
        struct sched_port p[MAX_NPORTS];
        struct tasklet_struct sched_tsk;/* tasklet used to run scheduler */
};
static void restart_sched(unsigned long);


/*
 * Main SGE data structure
 *
 * Interrupts are handled by a single CPU and it is likely that on a MP system
 * the application is migrated to another CPU. In that scenario, we try to
 * seperate the RX(in irq context) and TX state in order to decrease memory
 * contention.
 */
struct sge {
        struct adapter *adapter;        /* adapter backpointer */
        struct net_device *netdev;      /* netdevice backpointer */
        struct freelQ   freelQ[SGE_FREELQ_N]; /* buffer free lists */
        struct respQ    respQ;          /* response Q */
        unsigned long   stopped_tx_queues; /* bitmap of suspended Tx queues */
        unsigned int    rx_pkt_pad;     /* RX padding for L2 packets */
        unsigned int    jumbo_fl;       /* jumbo freelist Q index */
        unsigned int    intrtimer_nres; /* no-resource interrupt timer */
        unsigned int    fixed_intrtimer;/* non-adaptive interrupt timer */
        struct timer_list tx_reclaim_timer; /* reclaims TX buffers */
        struct timer_list espibug_timer;
        unsigned long   espibug_timeout;
        struct sk_buff  *espibug_skb[MAX_NPORTS];
        u32             sge_control;    /* shadow value of sge control reg */
        struct sge_intr_counts stats;
        struct sge_port_stats *port_stats[MAX_NPORTS];
        struct sched    *tx_sched;
        struct cmdQ cmdQ[SGE_CMDQ_N] ____cacheline_aligned_in_smp;
};

/*
 * stop tasklet and free all pending skb's
 */
static void tx_sched_stop(struct sge *sge)
{
        struct sched *s = sge->tx_sched;
        int i;

        tasklet_kill(&s->sched_tsk);

        for (i = 0; i < MAX_NPORTS; i++)
                __skb_queue_purge(&s->p[s->port].skbq);
}

/*
 * t1_sched_update_parms() is called when the MTU or link speed changes. It
 * re-computes scheduler parameters to scope with the change.
 */
unsigned int t1_sched_update_parms(struct sge *sge, unsigned int port,
                                   unsigned int mtu, unsigned int speed)
{
        struct sched *s = sge->tx_sched;
        struct sched_port *p = &s->p[port];
        unsigned int max_avail_segs;

        pr_debug("t1_sched_update_params mtu=%d speed=%d\n", mtu, speed);
        if (speed)
                p->speed = speed;
        if (mtu)
                p->mtu = mtu;

        if (speed || mtu) {
                unsigned long long drain = 1024ULL * p->speed * (p->mtu - 40);
                do_div(drain, (p->mtu + 50) * 1000);
                p->drain_bits_per_1024ns = (unsigned int) drain;

                if (p->speed < 1000)
                        p->drain_bits_per_1024ns =
                                90 * p->drain_bits_per_1024ns / 100;
        }

        if (board_info(sge->adapter)->board == CHBT_BOARD_CHT204) {
                p->drain_bits_per_1024ns -= 16;
                s->max_avail = max(4096U, p->mtu + 16 + 14 + 4);
                max_avail_segs = max(1U, 4096 / (p->mtu - 40));
        } else {
                s->max_avail = 16384;
                max_avail_segs = max(1U, 9000 / (p->mtu - 40));
        }

        pr_debug("t1_sched_update_parms: mtu %u speed %u max_avail %u "
                 "max_avail_segs %u drain_bits_per_1024ns %u\n", p->mtu,
                 p->speed, s->max_avail, max_avail_segs,
                 p->drain_bits_per_1024ns);

        return max_avail_segs * (p->mtu - 40);
}

/*
 * t1_sched_max_avail_bytes() tells the scheduler the maximum amount of
 * data that can be pushed per port.
 */
void t1_sched_set_max_avail_bytes(struct sge *sge, unsigned int val)
{
        struct sched *s = sge->tx_sched;
        unsigned int i;

        s->max_avail = val;
        for (i = 0; i < MAX_NPORTS; i++)
                t1_sched_update_parms(sge, i, 0, 0);
}

/*
 * t1_sched_set_drain_bits_per_us() tells the scheduler at which rate a port
 * is draining.
 */
void t1_sched_set_drain_bits_per_us(struct sge *sge, unsigned int port,
                                         unsigned int val)
{
        struct sched *s = sge->tx_sched;
        struct sched_port *p = &s->p[port];
        p->drain_bits_per_1024ns = val * 1024 / 1000;
        t1_sched_update_parms(sge, port, 0, 0);
}


/*
 * get_clock() implements a ns clock (see ktime_get)
 */
static inline ktime_t get_clock(void)
{
        struct timespec ts;

        ktime_get_ts(&ts);
        return timespec_to_ktime(ts);
}

/*
 * tx_sched_init() allocates resources and does basic initialization.
 */
static int tx_sched_init(struct sge *sge)
{
        struct sched *s;
        int i;

        s = kzalloc(sizeof (struct sched), GFP_KERNEL);
        if (!s)
                return -ENOMEM;

        pr_debug("tx_sched_init\n");
        tasklet_init(&s->sched_tsk, restart_sched, (unsigned long) sge);
        sge->tx_sched = s;

        for (i = 0; i < MAX_NPORTS; i++) {
                skb_queue_head_init(&s->p[i].skbq);
                t1_sched_update_parms(sge, i, 1500, 1000);
        }

        return 0;
}

/*
 * sched_update_avail() computes the delta since the last time it was called
 * and updates the per port quota (number of bits that can be sent to the any
 * port).
 */
static inline int sched_update_avail(struct sge *sge)
{
        struct sched *s = sge->tx_sched;
        ktime_t now = get_clock();
        unsigned int i;
        long long delta_time_ns;

        delta_time_ns = ktime_to_ns(ktime_sub(now, s->last_updated));

        pr_debug("sched_update_avail delta=%lld\n", delta_time_ns);
        if (delta_time_ns < 15000)
                return 0;

        for (i = 0; i < MAX_NPORTS; i++) {
                struct sched_port *p = &s->p[i];
                unsigned int delta_avail;

                delta_avail = (p->drain_bits_per_1024ns * delta_time_ns) >> 13;
                p->avail = min(p->avail + delta_avail, s->max_avail);
        }

        s->last_updated = now;

        return 1;
}

/*
 * sched_skb() is called from two different places. In the tx path, any
 * packet generating load on an output port will call sched_skb()
 * (skb != NULL). In addition, sched_skb() is called from the irq/soft irq
 * context (skb == NULL).
 * The scheduler only returns a skb (which will then be sent) if the
 * length of the skb is <= the current quota of the output port.
 */
static struct sk_buff *sched_skb(struct sge *sge, struct sk_buff *skb,
                                unsigned int credits)
{
        struct sched *s = sge->tx_sched;
        struct sk_buff_head *skbq;
        unsigned int i, len, update = 1;

        pr_debug("sched_skb %p\n", skb);
        if (!skb) {
                if (!s->num)
                        return NULL;
        } else {
                skbq = &s->p[skb->dev->if_port].skbq;
                __skb_queue_tail(skbq, skb);
                s->num++;
                skb = NULL;
        }

        if (credits < MAX_SKB_FRAGS + 1)
                goto out;

 again:
        for (i = 0; i < MAX_NPORTS; i++) {
                s->port = ++s->port & (MAX_NPORTS - 1);
                skbq = &s->p[s->port].skbq;

                skb = skb_peek(skbq);

                if (!skb)
                        continue;

                len = skb->len;
                if (len <= s->p[s->port].avail) {
                        s->p[s->port].avail -= len;
                        s->num--;
                        __skb_unlink(skb, skbq);
                        goto out;
                }
                skb = NULL;
        }

        if (update-- && sched_update_avail(sge))
                goto again;

 out:
        /* If there are more pending skbs, we use the hardware to schedule us
         * again.
         */
        if (s->num && !skb) {
                struct cmdQ *q = &sge->cmdQ[0];
                clear_bit(CMDQ_STAT_LAST_PKT_DB, &q->status);
                if (test_and_set_bit(CMDQ_STAT_RUNNING, &q->status) == 0) {
                        set_bit(CMDQ_STAT_LAST_PKT_DB, &q->status);
                        writel(F_CMDQ0_ENABLE, sge->adapter->regs + A_SG_DOORBELL);
                }
        }
        pr_debug("sched_skb ret %p\n", skb);

        return skb;
}

/*
 * PIO to indicate that memory mapped Q contains valid descriptor(s).
 */
static inline void doorbell_pio(struct adapter *adapter, u32 val)
{
        wmb();
        writel(val, adapter->regs + A_SG_DOORBELL);
}

/*
 * Frees all RX buffers on the freelist Q. The caller must make sure that
 * the SGE is turned off before calling this function.
 */
static void free_freelQ_buffers(struct pci_dev *pdev, struct freelQ *q)
{
        unsigned int cidx = q->cidx;

        while (q->credits--) {
                struct freelQ_ce *ce = &q->centries[cidx];

                pci_unmap_single(pdev, pci_unmap_addr(ce, dma_addr),
                                 pci_unmap_len(ce, dma_len),
                                 PCI_DMA_FROMDEVICE);
                dev_kfree_skb(ce->skb);
                ce->skb = NULL;
                if (++cidx == q->size)
                        cidx = 0;
        }
}

/*
 * Free RX free list and response queue resources.
 */
static void free_rx_resources(struct sge *sge)
{
        struct pci_dev *pdev = sge->adapter->pdev;
        unsigned int size, i;

        if (sge->respQ.entries) {
                size = sizeof(struct respQ_e) * sge->respQ.size;
                pci_free_consistent(pdev, size, sge->respQ.entries,
                                    sge->respQ.dma_addr);
        }

        for (i = 0; i < SGE_FREELQ_N; i++) {
                struct freelQ *q = &sge->freelQ[i];

                if (q->centries) {
                        free_freelQ_buffers(pdev, q);
                        kfree(q->centries);
                }
                if (q->entries) {
                        size = sizeof(struct freelQ_e) * q->size;
                        pci_free_consistent(pdev, size, q->entries,
                                            q->dma_addr);
                }
        }
}

/*
 * Allocates basic RX resources, consisting of memory mapped freelist Qs and a
 * response queue.
 */
static int alloc_rx_resources(struct sge *sge, struct sge_params *p)
{
        struct pci_dev *pdev = sge->adapter->pdev;
        unsigned int size, i;

        for (i = 0; i < SGE_FREELQ_N; i++) {
                struct freelQ *q = &sge->freelQ[i];

                q->genbit = 1;
                q->size = p->freelQ_size[i];
                q->dma_offset = sge->rx_pkt_pad ? 0 : NET_IP_ALIGN;
                size = sizeof(struct freelQ_e) * q->size;
                q->entries = (struct freelQ_e *)
                              pci_alloc_consistent(pdev, size, &q->dma_addr);
                if (!q->entries)
                        goto err_no_mem;
                memset(q->entries, 0, size);
                size = sizeof(struct freelQ_ce) * q->size;
                q->centries = kzalloc(size, GFP_KERNEL);
                if (!q->centries)
                        goto err_no_mem;
        }

        /*
         * Calculate the buffer sizes for the two free lists.  FL0 accommodates
         * regular sized Ethernet frames, FL1 is sized not to exceed 16K,
         * including all the sk_buff overhead.
         *
         * Note: For T2 FL0 and FL1 are reversed.
         */
        sge->freelQ[!sge->jumbo_fl].rx_buffer_size = SGE_RX_SM_BUF_SIZE +
                sizeof(struct cpl_rx_data) +
                sge->freelQ[!sge->jumbo_fl].dma_offset;

                size = (16 * 1024) -
                    SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

        sge->freelQ[sge->jumbo_fl].rx_buffer_size = size;

        /*
         * Setup which skb recycle Q should be used when recycling buffers from
         * each free list.
         */
        sge->freelQ[!sge->jumbo_fl].recycleq_idx = 0;
        sge->freelQ[sge->jumbo_fl].recycleq_idx = 1;

        sge->respQ.genbit = 1;
        sge->respQ.size = SGE_RESPQ_E_N;
        sge->respQ.credits = 0;
        size = sizeof(struct respQ_e) * sge->respQ.size;
        sge->respQ.entries = (struct respQ_e *)
                pci_alloc_consistent(pdev, size, &sge->respQ.dma_addr);
        if (!sge->respQ.entries)
                goto err_no_mem;
        memset(sge->respQ.entries, 0, size);
        return 0;

err_no_mem:
        free_rx_resources(sge);
        return -ENOMEM;
}

/*
 * Reclaims n TX descriptors and frees the buffers associated with them.
 */
static void free_cmdQ_buffers(struct sge *sge, struct cmdQ *q, unsigned int n)
{
        struct cmdQ_ce *ce;
        struct pci_dev *pdev = sge->adapter->pdev;
        unsigned int cidx = q->cidx;

        q->in_use -= n;
        ce = &q->centries[cidx];
        while (n--) {
                if (q->sop) {
                        if (likely(pci_unmap_len(ce, dma_len))) {
                                pci_unmap_single(pdev,
                                                 pci_unmap_addr(ce, dma_addr),
                                                 pci_unmap_len(ce, dma_len),
                                                 PCI_DMA_TODEVICE);
                                q->sop = 0;
                        }
                } else {
                        if (likely(pci_unmap_len(ce, dma_len))) {
                                pci_unmap_page(pdev, pci_unmap_addr(ce, dma_addr),
                                               pci_unmap_len(ce, dma_len),
                                               PCI_DMA_TODEVICE);
                        }
                }
                if (ce->skb) {
                        dev_kfree_skb_any(ce->skb);
                        q->sop = 1;
                }
                ce++;
                if (++cidx == q->size) {
                        cidx = 0;
                        ce = q->centries;
                }
        }
        q->cidx = cidx;
}

/*
 * Free TX resources.
 *
 * Assumes that SGE is stopped and all interrupts are disabled.
 */
static void free_tx_resources(struct sge *sge)
{
        struct pci_dev *pdev = sge->adapter->pdev;
        unsigned int size, i;

        for (i = 0; i < SGE_CMDQ_N; i++) {
                struct cmdQ *q = &sge->cmdQ[i];

                if (q->centries) {
                        if (q->in_use)
                                free_cmdQ_buffers(sge, q, q->in_use);
                        kfree(q->centries);
                }
                if (q->entries) {
                        size = sizeof(struct cmdQ_e) * q->size;
                        pci_free_consistent(pdev, size, q->entries,
                                            q->dma_addr);
                }
        }
}

/*
 * Allocates basic TX resources, consisting of memory mapped command Qs.
 */
static int alloc_tx_resources(struct sge *sge, struct sge_params *p)
{
        struct pci_dev *pdev = sge->adapter->pdev;
        unsigned int size, i;

        for (i = 0; i < SGE_CMDQ_N; i++) {
                struct cmdQ *q = &sge->cmdQ[i];

                q->genbit = 1;
                q->sop = 1;
                q->size = p->cmdQ_size[i];
                q->in_use = 0;
                q->status = 0;
                q->processed = q->cleaned = 0;
                q->stop_thres = 0;
                spin_lock_init(&q->lock);
                size = sizeof(struct cmdQ_e) * q->size;
                q->entries = (struct cmdQ_e *)
                              pci_alloc_consistent(pdev, size, &q->dma_addr);
                if (!q->entries)
                        goto err_no_mem;
                memset(q->entries, 0, size);
                size = sizeof(struct cmdQ_ce) * q->size;
                q->centries = kzalloc(size, GFP_KERNEL);
                if (!q->centries)
                        goto err_no_mem;
        }

        /*
         * CommandQ 0 handles Ethernet and TOE packets, while queue 1 is TOE
         * only.  For queue 0 set the stop threshold so we can handle one more
         * packet from each port, plus reserve an additional 24 entries for
         * Ethernet packets only.  Queue 1 never suspends nor do we reserve
         * space for Ethernet packets.
         */
        sge->cmdQ[0].stop_thres = sge->adapter->params.nports *
                (MAX_SKB_FRAGS + 1);
        return 0;

err_no_mem:
        free_tx_resources(sge);
        return -ENOMEM;
}

static inline void setup_ring_params(struct adapter *adapter, u64 addr,
                                     u32 size, int base_reg_lo,
                                     int base_reg_hi, int size_reg)
{
        writel((u32)addr, adapter->regs + base_reg_lo);
        writel(addr >> 32, adapter->regs + base_reg_hi);
        writel(size, adapter->regs + size_reg);
}

/*
 * Enable/disable VLAN acceleration.
 */
void t1_set_vlan_accel(struct adapter *adapter, int on_off)
{
        struct sge *sge = adapter->sge;

        sge->sge_control &= ~F_VLAN_XTRACT;
        if (on_off)
                sge->sge_control |= F_VLAN_XTRACT;
        if (adapter->open_device_map) {
                writel(sge->sge_control, adapter->regs + A_SG_CONTROL);
                readl(adapter->regs + A_SG_CONTROL);   /* flush */
        }
}

/*
 * Programs the various SGE registers. However, the engine is not yet enabled,
 * but sge->sge_control is setup and ready to go.
 */
static void configure_sge(struct sge *sge, struct sge_params *p)
{
        struct adapter *ap = sge->adapter;
        
        writel(0, ap->regs + A_SG_CONTROL);
        setup_ring_params(ap, sge->cmdQ[0].dma_addr, sge->cmdQ[0].size,
                          A_SG_CMD0BASELWR, A_SG_CMD0BASEUPR, A_SG_CMD0SIZE);
        setup_ring_params(ap, sge->cmdQ[1].dma_addr, sge->cmdQ[1].size,
                          A_SG_CMD1BASELWR, A_SG_CMD1BASEUPR, A_SG_CMD1SIZE);
        setup_ring_params(ap, sge->freelQ[0].dma_addr,
                          sge->freelQ[0].size, A_SG_FL0BASELWR,
                          A_SG_FL0BASEUPR, A_SG_FL0SIZE);
        setup_ring_params(ap, sge->freelQ[1].dma_addr,
                          sge->freelQ[1].size, A_SG_FL1BASELWR,
                          A_SG_FL1BASEUPR, A_SG_FL1SIZE);

        /* The threshold comparison uses <. */
        writel(SGE_RX_SM_BUF_SIZE + 1, ap->regs + A_SG_FLTHRESHOLD);

        setup_ring_params(ap, sge->respQ.dma_addr, sge->respQ.size,
                          A_SG_RSPBASELWR, A_SG_RSPBASEUPR, A_SG_RSPSIZE);
        writel((u32)sge->respQ.size - 1, ap->regs + A_SG_RSPQUEUECREDIT);

        sge->sge_control = F_CMDQ0_ENABLE | F_CMDQ1_ENABLE | F_FL0_ENABLE |
                F_FL1_ENABLE | F_CPL_ENABLE | F_RESPONSE_QUEUE_ENABLE |
                V_CMDQ_PRIORITY(2) | F_DISABLE_CMDQ1_GTS | F_ISCSI_COALESCE |
                V_RX_PKT_OFFSET(sge->rx_pkt_pad);

#if defined(__BIG_ENDIAN_BITFIELD)
        sge->sge_control |= F_ENABLE_BIG_ENDIAN;
#endif

        /* Initialize no-resource timer */
        sge->intrtimer_nres = SGE_INTRTIMER_NRES * core_ticks_per_usec(ap);

        t1_sge_set_coalesce_params(sge, p);
}

/*
 * Return the payload capacity of the jumbo free-list buffers.
 */
static inline unsigned int jumbo_payload_capacity(const struct sge *sge)
{
        return sge->freelQ[sge->jumbo_fl].rx_buffer_size -
                sge->freelQ[sge->jumbo_fl].dma_offset -
                sizeof(struct cpl_rx_data);
}

/*
 * Frees all SGE related resources and the sge structure itself
 */
void t1_sge_destroy(struct sge *sge)
{
        int i;

        for_each_port(sge->adapter, i)
                free_percpu(sge->port_stats[i]);

        kfree(sge->tx_sched);
        free_tx_resources(sge);
        free_rx_resources(sge);
        kfree(sge);
}

/*
 * Allocates new RX buffers on the freelist Q (and tracks them on the freelist
 * context Q) until the Q is full or alloc_skb fails.
 *
 * It is possible that the generation bits already match, indicating that the
 * buffer is already valid and nothing needs to be done. This happens when we
 * copied a received buffer into a new sk_buff during the interrupt processing.
 *
 * If the SGE doesn't automatically align packets properly (!sge->rx_pkt_pad),
 * we specify a RX_OFFSET in order to make sure that the IP header is 4B
 * aligned.
 */
static void refill_free_list(struct sge *sge, struct freelQ *q)
{
        struct pci_dev *pdev = sge->adapter->pdev;
        struct freelQ_ce *ce = &q->centries[q->pidx];
        struct freelQ_e *e = &q->entries[q->pidx];
        unsigned int dma_len = q->rx_buffer_size - q->dma_offset;


        while (q->credits < q->size) {
                struct sk_buff *skb;
                dma_addr_t mapping;

                skb = alloc_skb(q->rx_buffer_size, GFP_ATOMIC);
                if (!skb)
                        break;

                skb_reserve(skb, q->dma_offset);
                mapping = pci_map_single(pdev, skb->data, dma_len,
                                         PCI_DMA_FROMDEVICE);
                ce->skb = skb;
                pci_unmap_addr_set(ce, dma_addr, mapping);
                pci_unmap_len_set(ce, dma_len, dma_len);
                e->addr_lo = (u32)mapping;
                e->addr_hi = (u64)mapping >> 32;
                e->len_gen = V_CMD_LEN(dma_len) | V_CMD_GEN1(q->genbit);
                wmb();
                e->gen2 = V_CMD_GEN2(q->genbit);

                e++;
                ce++;
                if (++q->pidx == q->size) {
                        q->pidx = 0;
                        q->genbit ^= 1;
                        ce = q->centries;
                        e = q->entries;
                }
                q->credits++;
        }

}

/*
 * Calls refill_free_list for both free lists. If we cannot fill at least 1/4
 * of both rings, we go into 'few interrupt mode' in order to give the system
 * time to free up resources.
 */
static void freelQs_empty(struct sge *sge)
{
        struct adapter *adapter = sge->adapter;
        u32 irq_reg = readl(adapter->regs + A_SG_INT_ENABLE);
        u32 irqholdoff_reg;

        refill_free_list(sge, &sge->freelQ[0]);
        refill_free_list(sge, &sge->freelQ[1]);

        if (sge->freelQ[0].credits > (sge->freelQ[0].size >> 2) &&
            sge->freelQ[1].credits > (sge->freelQ[1].size >> 2)) {
                irq_reg |= F_FL_EXHAUSTED;
                irqholdoff_reg = sge->fixed_intrtimer;
        } else {
                /* Clear the F_FL_EXHAUSTED interrupts for now */
                irq_reg &= ~F_FL_EXHAUSTED;
                irqholdoff_reg = sge->intrtimer_nres;
        }
        writel(irqholdoff_reg, adapter->regs + A_SG_INTRTIMER);
        writel(irq_reg, adapter->regs + A_SG_INT_ENABLE);

        /* We reenable the Qs to force a freelist GTS interrupt later */
        doorbell_pio(adapter, F_FL0_ENABLE | F_FL1_ENABLE);
}

#define SGE_PL_INTR_MASK (F_PL_INTR_SGE_ERR | F_PL_INTR_SGE_DATA)
#define SGE_INT_FATAL (F_RESPQ_OVERFLOW | F_PACKET_TOO_BIG | F_PACKET_MISMATCH)
#define SGE_INT_ENABLE (F_RESPQ_EXHAUSTED | F_RESPQ_OVERFLOW | \
                        F_FL_EXHAUSTED | F_PACKET_TOO_BIG | F_PACKET_MISMATCH)

/*
 * Disable SGE Interrupts
 */
void t1_sge_intr_disable(struct sge *sge)
{
        u32 val = readl(sge->adapter->regs + A_PL_ENABLE);

        writel(val & ~SGE_PL_INTR_MASK, sge->adapter->regs + A_PL_ENABLE);
        writel(0, sge->adapter->regs + A_SG_INT_ENABLE);
}

/*
 * Enable SGE interrupts.
 */
void t1_sge_intr_enable(struct sge *sge)
{
        u32 en = SGE_INT_ENABLE;
        u32 val = readl(sge->adapter->regs + A_PL_ENABLE);

        if (sge->adapter->flags & TSO_CAPABLE)
                en &= ~F_PACKET_TOO_BIG;
        writel(en, sge->adapter->regs + A_SG_INT_ENABLE);
        writel(val | SGE_PL_INTR_MASK, sge->adapter->regs + A_PL_ENABLE);
}

/*
 * Clear SGE interrupts.
 */
void t1_sge_intr_clear(struct sge *sge)
{
        writel(SGE_PL_INTR_MASK, sge->adapter->regs + A_PL_CAUSE);
        writel(0xffffffff, sge->adapter->regs + A_SG_INT_CAUSE);
}

/*
 * SGE 'Error' interrupt handler
 */
int t1_sge_intr_error_handler(struct sge *sge)
{
        struct adapter *adapter = sge->adapter;
        u32 cause = readl(adapter->regs + A_SG_INT_CAUSE);

        if (adapter->flags & TSO_CAPABLE)
                cause &= ~F_PACKET_TOO_BIG;
        if (cause & F_RESPQ_EXHAUSTED)
                sge->stats.respQ_empty++;
        if (cause & F_RESPQ_OVERFLOW) {
                sge->stats.respQ_overflow++;
                CH_ALERT("%s: SGE response queue overflow\n",
                         adapter->name);
        }
        if (cause & F_FL_EXHAUSTED) {
                sge->stats.freelistQ_empty++;
                freelQs_empty(sge);
        }
        if (cause & F_PACKET_TOO_BIG) {
                sge->stats.pkt_too_big++;
                CH_ALERT("%s: SGE max packet size exceeded\n",
                         adapter->name);
        }
        if (cause & F_PACKET_MISMATCH) {
                sge->stats.pkt_mismatch++;
                CH_ALERT("%s: SGE packet mismatch\n", adapter->name);
        }
        if (cause & SGE_INT_FATAL)
                t1_fatal_err(adapter);

        writel(cause, adapter->regs + A_SG_INT_CAUSE);
        return 0;
}

const struct sge_intr_counts *t1_sge_get_intr_counts(const struct sge *sge)
{
        return &sge->stats;
}

void t1_sge_get_port_stats(const struct sge *sge, int port,
                           struct sge_port_stats *ss)
{
        int cpu;

        memset(ss, 0, sizeof(*ss));
        for_each_possible_cpu(cpu) {
                struct sge_port_stats *st = per_cpu_ptr(sge->port_stats[port], cpu);

                ss->rx_packets += st->rx_packets;
                ss->rx_cso_good += st->rx_cso_good;
                ss->tx_packets += st->tx_packets;
                ss->tx_cso += st->tx_cso;
                ss->tx_tso += st->tx_tso;
                ss->vlan_xtract += st->vlan_xtract;
                ss->vlan_insert += st->vlan_insert;
        }
}

/**
 *      recycle_fl_buf - recycle a free list buffer
 *      @fl: the free list
 *      @idx: index of buffer to recycle
 *
 *      Recycles the specified buffer on the given free list by adding it at
 *      the next available slot on the list.
 */
static void recycle_fl_buf(struct freelQ *fl, int idx)
{
        struct freelQ_e *from = &fl->entries[idx];
        struct freelQ_e *to = &fl->entries[fl->pidx];

        fl->centries[fl->pidx] = fl->centries[idx];
        to->addr_lo = from->addr_lo;
        to->addr_hi = from->addr_hi;
        to->len_gen = G_CMD_LEN(from->len_gen) | V_CMD_GEN1(fl->genbit);
        wmb();
        to->gen2 = V_CMD_GEN2(fl->genbit);
        fl->credits++;

        if (++fl->pidx == fl->size) {
                fl->pidx = 0;
                fl->genbit ^= 1;
        }
}

/**
 *      get_packet - return the next ingress packet buffer
 *      @pdev: the PCI device that received the packet
 *      @fl: the SGE free list holding the packet
 *      @len: the actual packet length, excluding any SGE padding
 *      @dma_pad: padding at beginning of buffer left by SGE DMA
 *      @skb_pad: padding to be used if the packet is copied
 *      @copy_thres: length threshold under which a packet should be copied
 *      @drop_thres: # of remaining buffers before we start dropping packets
 *
 *      Get the next packet from a free list and complete setup of the
 *      sk_buff.  If the packet is small we make a copy and recycle the
 *      original buffer, otherwise we use the original buffer itself.  If a
 *      positive drop threshold is supplied packets are dropped and their
 *      buffers recycled if (a) the number of remaining buffers is under the
 *      threshold and the packet is too big to copy, or (b) the packet should
 *      be copied but there is no memory for the copy.
 */
static inline struct sk_buff *get_packet(struct pci_dev *pdev,
                                         struct freelQ *fl, unsigned int len,
                                         int dma_pad, int skb_pad,
                                         unsigned int copy_thres,
                                         unsigned int drop_thres)
{
        struct sk_buff *skb;
        struct freelQ_ce *ce = &fl->centries[fl->cidx];

        if (len < copy_thres) {
                skb = alloc_skb(len + skb_pad, GFP_ATOMIC);
                if (likely(skb != NULL)) {
                        skb_reserve(skb, skb_pad);
                        skb_put(skb, len);
                        pci_dma_sync_single_for_cpu(pdev,
                                            pci_unmap_addr(ce, dma_addr),
                                            pci_unmap_len(ce, dma_len),
                                            PCI_DMA_FROMDEVICE);
                        memcpy(skb->data, ce->skb->data + dma_pad, len);
                        pci_dma_sync_single_for_device(pdev,
                                            pci_unmap_addr(ce, dma_addr),
                                            pci_unmap_len(ce, dma_len),
                                            PCI_DMA_FROMDEVICE);
                } else if (!drop_thres)
                        goto use_orig_buf;

                recycle_fl_buf(fl, fl->cidx);
                return skb;
        }

        if (fl->credits < drop_thres) {
                recycle_fl_buf(fl, fl->cidx);
                return NULL;
        }

use_orig_buf:
        pci_unmap_single(pdev, pci_unmap_addr(ce, dma_addr),
                         pci_unmap_len(ce, dma_len), PCI_DMA_FROMDEVICE);
        skb = ce->skb;
        skb_reserve(skb, dma_pad);
        skb_put(skb, len);
        return skb;
}

/**
 *      unexpected_offload - handle an unexpected offload packet
 *      @adapter: the adapter
 *      @fl: the free list that received the packet
 *
 *      Called when we receive an unexpected offload packet (e.g., the TOE
 *      function is disabled or the card is a NIC).  Prints a message and
 *      recycles the buffer.
 */
static void unexpected_offload(struct adapter *adapter, struct freelQ *fl)
{
        struct freelQ_ce *ce = &fl->centries[fl->cidx];
        struct sk_buff *skb = ce->skb;

        pci_dma_sync_single_for_cpu(adapter->pdev, pci_unmap_addr(ce, dma_addr),
                            pci_unmap_len(ce, dma_len), PCI_DMA_FROMDEVICE);
        CH_ERR("%s: unexpected offload packet, cmd %u\n",
               adapter->name, *skb->data);
        recycle_fl_buf(fl, fl->cidx);
}

/*
 * T1/T2 SGE limits the maximum DMA size per TX descriptor to
 * SGE_TX_DESC_MAX_PLEN (16KB). If the PAGE_SIZE is larger than 16KB, the
 * stack might send more than SGE_TX_DESC_MAX_PLEN in a contiguous manner.
 * Note that the *_large_page_tx_descs stuff will be optimized out when
 * PAGE_SIZE <= SGE_TX_DESC_MAX_PLEN.
 *
 * compute_large_page_descs() computes how many additional descriptors are
 * required to break down the stack's request.
 */
static inline unsigned int compute_large_page_tx_descs(struct sk_buff *skb)
{
        unsigned int count = 0;
        if (PAGE_SIZE > SGE_TX_DESC_MAX_PLEN) {
                unsigned int nfrags = skb_shinfo(skb)->nr_frags;
                unsigned int i, len = skb->len - skb->data_len;
                while (len > SGE_TX_DESC_MAX_PLEN) {
                        count++;
                        len -= SGE_TX_DESC_MAX_PLEN;
                }
                for (i = 0; nfrags--; i++) {
                        skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
                        len = frag->size;
                        while (len > SGE_TX_DESC_MAX_PLEN) {
                                count++;
                                len -= SGE_TX_DESC_MAX_PLEN;
                        }
                }
        }
        return count;
}

/*
 * Write a cmdQ entry.
 *
 * Since this function writes the 'flags' field, it must not be used to
 * write the first cmdQ entry.
 */
static inline void write_tx_desc(struct cmdQ_e *e, dma_addr_t mapping,
                                 unsigned int len, unsigned int gen,
                                 unsigned int eop)
{
        if (unlikely(len > SGE_TX_DESC_MAX_PLEN))
                BUG();
        e->addr_lo = (u32)mapping;
        e->addr_hi = (u64)mapping >> 32;
        e->len_gen = V_CMD_LEN(len) | V_CMD_GEN1(gen);
        e->flags = F_CMD_DATAVALID | V_CMD_EOP(eop) | V_CMD_GEN2(gen);
}

/*
 * See comment for previous function.
 *
 * write_tx_descs_large_page() writes additional SGE tx descriptors if
 * *desc_len exceeds HW's capability.
 */
static inline unsigned int write_large_page_tx_descs(unsigned int pidx,
                                                     struct cmdQ_e **e,
                                                     struct cmdQ_ce **ce,
                                                     unsigned int *gen,
                                                     dma_addr_t *desc_mapping,
                                                     unsigned int *desc_len,
                                                     unsigned int nfrags,
                                                     struct cmdQ *q)
{
        if (PAGE_SIZE > SGE_TX_DESC_MAX_PLEN) {
                struct cmdQ_e *e1 = *e;
                struct cmdQ_ce *ce1 = *ce;

                while (*desc_len > SGE_TX_DESC_MAX_PLEN) {
                        *desc_len -= SGE_TX_DESC_MAX_PLEN;
                        write_tx_desc(e1, *desc_mapping, SGE_TX_DESC_MAX_PLEN,
                                      *gen, nfrags == 0 && *desc_len == 0);
                        ce1->skb = NULL;
                        pci_unmap_len_set(ce1, dma_len, 0);
                        *desc_mapping += SGE_TX_DESC_MAX_PLEN;
                        if (*desc_len) {
                                ce1++;
                                e1++;
                                if (++pidx == q->size) {
                                        pidx = 0;
                                        *gen ^= 1;
                                        ce1 = q->centries;
                                        e1 = q->entries;
                                }
                        }
                }
                *e = e1;
                *ce = ce1;
        }
        return pidx;
}

/*
 * Write the command descriptors to transmit the given skb starting at
 * descriptor pidx with the given generation.
 */
static inline void write_tx_descs(struct adapter *adapter, struct sk_buff *skb,
                                  unsigned int pidx, unsigned int gen,
                                  struct cmdQ *q)
{
        dma_addr_t mapping, desc_mapping;
        struct cmdQ_e *e, *e1;
        struct cmdQ_ce *ce;
        unsigned int i, flags, first_desc_len, desc_len,
            nfrags = skb_shinfo(skb)->nr_frags;

        e = e1 = &q->entries[pidx];
        ce = &q->centries[pidx];

        mapping = pci_map_single(adapter->pdev, skb->data,
                                skb->len - skb->data_len, PCI_DMA_TODEVICE);

        desc_mapping = mapping;
        desc_len = skb->len - skb->data_len;

        flags = F_CMD_DATAVALID | F_CMD_SOP |
            V_CMD_EOP(nfrags == 0 && desc_len <= SGE_TX_DESC_MAX_PLEN) |
            V_CMD_GEN2(gen);
        first_desc_len = (desc_len <= SGE_TX_DESC_MAX_PLEN) ?
            desc_len : SGE_TX_DESC_MAX_PLEN;
        e->addr_lo = (u32)desc_mapping;
        e->addr_hi = (u64)desc_mapping >> 32;
        e->len_gen = V_CMD_LEN(first_desc_len) | V_CMD_GEN1(gen);
        ce->skb = NULL;
        pci_unmap_len_set(ce, dma_len, 0);

        if (PAGE_SIZE > SGE_TX_DESC_MAX_PLEN &&
            desc_len > SGE_TX_DESC_MAX_PLEN) {
                desc_mapping += first_desc_len;
                desc_len -= first_desc_len;
                e1++;
                ce++;
                if (++pidx == q->size) {
                        pidx = 0;
                        gen ^= 1;
                        e1 = q->entries;
                        ce = q->centries;
                }
                pidx = write_large_page_tx_descs(pidx, &e1, &ce, &gen,
                                                 &desc_mapping, &desc_len,
                                                 nfrags, q);

                if (likely(desc_len))
                        write_tx_desc(e1, desc_mapping, desc_len, gen,
                                      nfrags == 0);
        }

        ce->skb = NULL;
        pci_unmap_addr_set(ce, dma_addr, mapping);
        pci_unmap_len_set(ce, dma_len, skb->len - skb->data_len);

        for (i = 0; nfrags--; i++) {
                skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
                e1++;
                ce++;
                if (++pidx == q->size) {
                        pidx = 0;
                        gen ^= 1;
                        e1 = q->entries;
                        ce = q->centries;
                }

                mapping = pci_map_page(adapter->pdev, frag->page,
                                       frag->page_offset, frag->size,
                                       PCI_DMA_TODEVICE);
                desc_mapping = mapping;
                desc_len = frag->size;

                pidx = write_large_page_tx_descs(pidx, &e1, &ce, &gen,
                                                 &desc_mapping, &desc_len,
                                                 nfrags, q);
                if (likely(desc_len))
                        write_tx_desc(e1, desc_mapping, desc_len, gen,
                                      nfrags == 0);
                ce->skb = NULL;
                pci_unmap_addr_set(ce, dma_addr, mapping);
                pci_unmap_len_set(ce, dma_len, frag->size);
        }
        ce->skb = skb;
        wmb();
        e->flags = flags;
}

/*
 * Clean up completed Tx buffers.
 */
static inline void reclaim_completed_tx(struct sge *sge, struct cmdQ *q)
{
        unsigned int reclaim = q->processed - q->cleaned;

        if (reclaim) {
                pr_debug("reclaim_completed_tx processed:%d cleaned:%d\n",
                         q->processed, q->cleaned);
                free_cmdQ_buffers(sge, q, reclaim);
                q->cleaned += reclaim;
        }
}

/*
 * Called from tasklet. Checks the scheduler for any
 * pending skbs that can be sent.
 */
static void restart_sched(unsigned long arg)
{
        struct sge *sge = (struct sge *) arg;
        struct adapter *adapter = sge->adapter;
        struct cmdQ *q = &sge->cmdQ[0];
        struct sk_buff *skb;
        unsigned int credits, queued_skb = 0;

        spin_lock(&q->lock);
        reclaim_completed_tx(sge, q);

        credits = q->size - q->in_use;
        pr_debug("restart_sched credits=%d\n", credits);
        while ((skb = sched_skb(sge, NULL, credits)) != NULL) {
                unsigned int genbit, pidx, count;
                count = 1 + skb_shinfo(skb)->nr_frags;
                count += compute_large_page_tx_descs(skb);
                q->in_use += count;
                genbit = q->genbit;
                pidx = q->pidx;
                q->pidx += count;
                if (q->pidx >= q->size) {
                        q->pidx -= q->size;
                        q->genbit ^= 1;
                }
                write_tx_descs(adapter, skb, pidx, genbit, q);
                credits = q->size - q->in_use;
                queued_skb = 1;
        }

        if (queued_skb) {
                clear_bit(CMDQ_STAT_LAST_PKT_DB, &q->status);
                if (test_and_set_bit(CMDQ_STAT_RUNNING, &q->status) == 0) {
                        set_bit(CMDQ_STAT_LAST_PKT_DB, &q->status);
                        writel(F_CMDQ0_ENABLE, adapter->regs + A_SG_DOORBELL);
                }
        }
        spin_unlock(&q->lock);
}

/**
 *      sge_rx - process an ingress ethernet packet
 *      @sge: the sge structure
 *      @fl: the free list that contains the packet buffer
 *      @len: the packet length
 *
 *      Process an ingress ethernet pakcet and deliver it to the stack.
 */
static int sge_rx(struct sge *sge, struct freelQ *fl, unsigned int len)
{
        struct sk_buff *skb;
        struct cpl_rx_pkt *p;
        struct adapter *adapter = sge->adapter;
        struct sge_port_stats *st;

        skb = get_packet(adapter->pdev, fl, len - sge->rx_pkt_pad,
                         sge->rx_pkt_pad, 2, SGE_RX_COPY_THRES,
                         SGE_RX_DROP_THRES);
        if (unlikely(!skb)) {
                sge->stats.rx_drops++;
                return 0;
        }

        p = (struct cpl_rx_pkt *)skb->data;
        skb_pull(skb, sizeof(*p));
        if (p->iff >= adapter->params.nports) {
                kfree_skb(skb);
                return 0;
        }

        skb->dev = adapter->port[p->iff].dev;
        skb->dev->last_rx = jiffies;
        st = per_cpu_ptr(sge->port_stats[p->iff], smp_processor_id());
        st->rx_packets++;

        skb->protocol = eth_type_trans(skb, skb->dev);
        if ((adapter->flags & RX_CSUM_ENABLED) && p->csum == 0xffff &&
            skb->protocol == htons(ETH_P_IP) &&
            (skb->data[9] == IPPROTO_TCP || skb->data[9] == IPPROTO_UDP)) {
                ++st->rx_cso_good;
                skb->ip_summed = CHECKSUM_UNNECESSARY;
        } else
                skb->ip_summed = CHECKSUM_NONE;

        if (unlikely(adapter->vlan_grp && p->vlan_valid)) {
                st->vlan_xtract++;
                if (adapter->params.sge.polling)
                        vlan_hwaccel_receive_skb(skb, adapter->vlan_grp,
                                                 ntohs(p->vlan));
                else
                        vlan_hwaccel_rx(skb, adapter->vlan_grp,
                                        ntohs(p->vlan));
        } else if (adapter->params.sge.polling)
                netif_receive_skb(skb);
        else
                netif_rx(skb);
        return 0;
}

/*
 * Returns true if a command queue has enough available descriptors that
 * we can resume Tx operation after temporarily disabling its packet queue.
 */
static inline int enough_free_Tx_descs(const struct cmdQ *q)
{
        unsigned int r = q->processed - q->cleaned;

        return q->in_use - r < (q->size >> 1);
}

/*
 * Called when sufficient space has become available in the SGE command queues
 * after the Tx packet schedulers have been suspended to restart the Tx path.
 */
static void restart_tx_queues(struct sge *sge)
{
        struct adapter *adap = sge->adapter;

        if (enough_free_Tx_descs(&sge->cmdQ[0])) {
                int i;

                for_each_port(adap, i) {
                        struct net_device *nd = adap->port[i].dev;

                        if (test_and_clear_bit(nd->if_port,
                                               &sge->stopped_tx_queues) &&
                            netif_running(nd)) {
                                sge->stats.cmdQ_restarted[2]++;
                                netif_wake_queue(nd);
                        }
                }
        }
}

/*
 * update_tx_info is called from the interrupt handler/NAPI to return cmdQ0 
 * information.
 */
static unsigned int update_tx_info(struct adapter *adapter, 
                                          unsigned int flags, 
                                          unsigned int pr0)
{
        struct sge *sge = adapter->sge;
        struct cmdQ *cmdq = &sge->cmdQ[0];

        cmdq->processed += pr0;
        if (flags & (F_FL0_ENABLE | F_FL1_ENABLE)) {
                freelQs_empty(sge);
                flags &= ~(F_FL0_ENABLE | F_FL1_ENABLE);
        }
        if (flags & F_CMDQ0_ENABLE) {
                clear_bit(CMDQ_STAT_RUNNING, &cmdq->status);

                if (cmdq->cleaned + cmdq->in_use != cmdq->processed &&
                    !test_and_set_bit(CMDQ_STAT_LAST_PKT_DB, &cmdq->status)) {
                        set_bit(CMDQ_STAT_RUNNING, &cmdq->status);
                        writel(F_CMDQ0_ENABLE, adapter->regs + A_SG_DOORBELL);
                }
                if (sge->tx_sched)
                        tasklet_hi_schedule(&sge->tx_sched->sched_tsk);

                flags &= ~F_CMDQ0_ENABLE;
        }

        if (unlikely(sge->stopped_tx_queues != 0))
                restart_tx_queues(sge);

        return flags;
}

/*
 * Process SGE responses, up to the supplied budget.  Returns the number of
 * responses processed.  A negative budget is effectively unlimited.
 */
static int process_responses(struct adapter *adapter, int budget)
{
        struct sge *sge = adapter->sge;
        struct respQ *q = &sge->respQ;
        struct respQ_e *e = &q->entries[q->cidx];
        int budget_left = budget;
        unsigned int flags = 0;
        unsigned int cmdq_processed[SGE_CMDQ_N] = {0, 0};
        

        while (likely(budget_left && e->GenerationBit == q->genbit)) {
                flags |= e->Qsleeping;
                
                cmdq_processed[0] += e->Cmdq0CreditReturn;
                cmdq_processed[1] += e->Cmdq1CreditReturn;
                
                /* We batch updates to the TX side to avoid cacheline
                 * ping-pong of TX state information on MP where the sender
                 * might run on a different CPU than this function...
                 */
                if (unlikely(flags & F_CMDQ0_ENABLE || cmdq_processed[0] > 64)) {
                        flags = update_tx_info(adapter, flags, cmdq_processed[0]);
                        cmdq_processed[0] = 0;
                }
                if (unlikely(cmdq_processed[1] > 16)) {
                        sge->cmdQ[1].processed += cmdq_processed[1];
                        cmdq_processed[1] = 0;
                }
                if (likely(e->DataValid)) {
                        struct freelQ *fl = &sge->freelQ[e->FreelistQid];

                        BUG_ON(!e->Sop || !e->Eop);
                        if (unlikely(e->Offload))
                                unexpected_offload(adapter, fl);
                        else
                                sge_rx(sge, fl, e->BufferLength);

                        /*
                         * Note: this depends on each packet consuming a
                         * single free-list buffer; cf. the BUG above.
                         */
                        if (++fl->cidx == fl->size)
                                fl->cidx = 0;
                        if (unlikely(--fl->credits <
                                     fl->size - SGE_FREEL_REFILL_THRESH))
                                refill_free_list(sge, fl);
                } else
                        sge->stats.pure_rsps++;

                e++;
                if (unlikely(++q->cidx == q->size)) {
                        q->cidx = 0;
                        q->genbit ^= 1;
                        e = q->entries;
                }
                prefetch(e);

                if (++q->credits > SGE_RESPQ_REPLENISH_THRES) {
                        writel(q->credits, adapter->regs + A_SG_RSPQUEUECREDIT);
                        q->credits = 0;
                }
                --budget_left;
        }

        flags = update_tx_info(adapter, flags, cmdq_processed[0]); 
        sge->cmdQ[1].processed += cmdq_processed[1];

        budget -= budget_left;
        return budget;
}

/*
 * A simpler version of process_responses() that handles only pure (i.e.,
 * non data-carrying) responses.  Such respones are too light-weight to justify
 * calling a softirq when using NAPI, so we handle them specially in hard
 * interrupt context.  The function is called with a pointer to a response,
 * which the caller must ensure is a valid pure response.  Returns 1 if it
 * encounters a valid data-carrying response, 0 otherwise.
 */
static int process_pure_responses(struct adapter *adapter, struct respQ_e *e)
{
        struct sge *sge = adapter->sge;
        struct respQ *q = &sge->respQ;
        unsigned int flags = 0;
        unsigned int cmdq_processed[SGE_CMDQ_N] = {0, 0};

        do {
                flags |= e->Qsleeping;

                cmdq_processed[0] += e->Cmdq0CreditReturn;
                cmdq_processed[1] += e->Cmdq1CreditReturn;
                
                e++;
                if (unlikely(++q->cidx == q->size)) {
                        q->cidx = 0;
                        q->genbit ^= 1;
                        e = q->entries;
                }
                prefetch(e);

                if (++q->credits > SGE_RESPQ_REPLENISH_THRES) {
                        writel(q->credits, adapter->regs + A_SG_RSPQUEUECREDIT);
                        q->credits = 0;
                }
                sge->stats.pure_rsps++;
        } while (e->GenerationBit == q->genbit && !e->DataValid);

        flags = update_tx_info(adapter, flags, cmdq_processed[0]); 
        sge->cmdQ[1].processed += cmdq_processed[1];

        return e->GenerationBit == q->genbit;
}

/*
 * Handler for new data events when using NAPI.  This does not need any locking
 * or protection from interrupts as data interrupts are off at this point and
 * other adapter interrupts do not interfere.
 */
static int t1_poll(struct net_device *dev, int *budget)
{
        struct adapter *adapter = dev->priv;
        int effective_budget = min(*budget, dev->quota);

        int work_done = process_responses(adapter, effective_budget);
        *budget -= work_done;
        dev->quota -= work_done;

        if (work_done >= effective_budget)
                return 1;

        __netif_rx_complete(dev);

        /*
         * Because we don't atomically flush the following write it is
         * possible that in very rare cases it can reach the device in a way
         * that races with a new response being written plus an error interrupt
         * causing the NAPI interrupt handler below to return unhandled status
         * to the OS.  To protect against this would require flushing the write
         * and doing both the write and the flush with interrupts off.  Way too
         * expensive and unjustifiable given the rarity of the race.
         */
        writel(adapter->sge->respQ.cidx, adapter->regs + A_SG_SLEEPING);
        return 0;
}

/*
 * Returns true if the device is already scheduled for polling.
 */
static inline int napi_is_scheduled(struct net_device *dev)
{
        return test_bit(__LINK_STATE_RX_SCHED, &dev->state);
}

/*
 * NAPI version of the main interrupt handler.
 */
static irqreturn_t t1_interrupt_napi(int irq, void *data)
{
        int handled;
        struct adapter *adapter = data;
        struct sge *sge = adapter->sge;
        struct respQ *q = &adapter->sge->respQ;

        /*
         * Clear the SGE_DATA interrupt first thing.  Normally the NAPI
         * handler has control of the response queue and the interrupt handler
         * can look at the queue reliably only once it knows NAPI is off.
         * We can't wait that long to clear the SGE_DATA interrupt because we
         * could race with t1_poll rearming the SGE interrupt, so we need to
         * clear the interrupt speculatively and really early on.
         */
        writel(F_PL_INTR_SGE_DATA, adapter->regs + A_PL_CAUSE);

        spin_lock(&adapter->async_lock);
        if (!napi_is_scheduled(sge->netdev)) {
                struct respQ_e *e = &q->entries[q->cidx];

                if (e->GenerationBit == q->genbit) {
                        if (e->DataValid ||
                            process_pure_responses(adapter, e)) {
                                if (likely(__netif_rx_schedule_prep(sge->netdev)))
                                        __netif_rx_schedule(sge->netdev);
                                else if (net_ratelimit())
                                        printk(KERN_INFO
                                               "NAPI schedule failure!\n");
                        } else
                                writel(q->cidx, adapter->regs + A_SG_SLEEPING);

                        handled = 1;
                        goto unlock;
                } else
                        writel(q->cidx, adapter->regs + A_SG_SLEEPING);
        }  else if (readl(adapter->regs + A_PL_CAUSE) & F_PL_INTR_SGE_DATA) {
                printk(KERN_ERR "data interrupt while NAPI running\n");
        }
        
        handled = t1_slow_intr_handler(adapter);
        if (!handled)
                sge->stats.unhandled_irqs++;
 unlock:
        spin_unlock(&adapter->async_lock);
        return IRQ_RETVAL(handled != 0);
}

/*
 * Main interrupt handler, optimized assuming that we took a 'DATA'
 * interrupt.
 *
 * 1. Clear the interrupt
 * 2. Loop while we find valid descriptors and process them; accumulate
 *      information that can be processed after the loop
 * 3. Tell the SGE at which index we stopped processing descriptors
 * 4. Bookkeeping; free TX buffers, ring doorbell if there are any
 *      outstanding TX buffers waiting, replenish RX buffers, potentially
 *      reenable upper layers if they were turned off due to lack of TX
 *      resources which are available again.
 * 5. If we took an interrupt, but no valid respQ descriptors was found we
 *      let the slow_intr_handler run and do error handling.
 */
static irqreturn_t t1_interrupt(int irq, void *cookie)
{
        int work_done;
        struct respQ_e *e;
        struct adapter *adapter = cookie;
        struct respQ *Q = &adapter->sge->respQ;

        spin_lock(&adapter->async_lock);
        e = &Q->entries[Q->cidx];
        prefetch(e);

        writel(F_PL_INTR_SGE_DATA, adapter->regs + A_PL_CAUSE);

        if (likely(e->GenerationBit == Q->genbit))
                work_done = process_responses(adapter, -1);
        else
                work_done = t1_slow_intr_handler(adapter);

        /*
         * The unconditional clearing of the PL_CAUSE above may have raced
         * with DMA completion and the corresponding generation of a response
         * to cause us to miss the resulting data interrupt.  The next write
         * is also unconditional to recover the missed interrupt and render
         * this race harmless.
         */
        writel(Q->cidx, adapter->regs + A_SG_SLEEPING);

        if (!work_done)
                adapter->sge->stats.unhandled_irqs++;
        spin_unlock(&adapter->async_lock);
        return IRQ_RETVAL(work_done != 0);
}

irq_handler_t t1_select_intr_handler(adapter_t *adapter)
{
        return adapter->params.sge.polling ? t1_interrupt_napi : t1_interrupt;
}

/*
 * Enqueues the sk_buff onto the cmdQ[qid] and has hardware fetch it.
 *
 * The code figures out how many entries the sk_buff will require in the
 * cmdQ and updates the cmdQ data structure with the state once the enqueue
 * has complete. Then, it doesn't access the global structure anymore, but
 * uses the corresponding fields on the stack. In conjuction with a spinlock
 * around that code, we can make the function reentrant without holding the
 * lock when we actually enqueue (which might be expensive, especially on
 * architectures with IO MMUs).
 *
 * This runs with softirqs disabled.
 */
static int t1_sge_tx(struct sk_buff *skb, struct adapter *adapter,
                     unsigned int qid, struct net_device *dev)
{
        struct sge *sge = adapter->sge;
        struct cmdQ *q = &sge->cmdQ[qid];
        unsigned int credits, pidx, genbit, count, use_sched_skb = 0;

        spin_lock(&q->lock);
        reclaim_completed_tx(sge, q);

        pidx = q->pidx;
        credits = q->size - q->in_use;
        count = 1 + skb_shinfo(skb)->nr_frags;
        count += compute_large_page_tx_descs(skb);

        /* Ethernet packet */
        if (unlikely(credits < count)) {
                if (!netif_queue_stopped(dev)) {
                        netif_stop_queue(dev);
                        set_bit(dev->if_port, &sge->stopped_tx_queues);
                        sge->stats.cmdQ_full[2]++;
                        CH_ERR("%s: Tx ring full while queue awake!\n",
                               adapter->name);
                }
                spin_unlock(&q->lock);
                return NETDEV_TX_BUSY;
        }

        if (unlikely(credits - count < q->stop_thres)) {
                netif_stop_queue(dev);
                set_bit(dev->if_port, &sge->stopped_tx_queues);
                sge->stats.cmdQ_full[2]++;
        }

        /* T204 cmdQ0 skbs that are destined for a certain port have to go
         * through the scheduler.
         */
        if (sge->tx_sched && !qid && skb->dev) {
        use_sched:
                use_sched_skb = 1;
                /* Note that the scheduler might return a different skb than
                 * the one passed in.
                 */
                skb = sched_skb(sge, skb, credits);
                if (!skb) {
                        spin_unlock(&q->lock);
                        return NETDEV_TX_OK;
                }
                pidx = q->pidx;
                count = 1 + skb_shinfo(skb)->nr_frags;
                count += compute_large_page_tx_descs(skb);
        }

        q->in_use += count;
        genbit = q->genbit;
        pidx = q->pidx;
        q->pidx += count;
        if (q->pidx >= q->size) {
                q->pidx -= q->size;
                q->genbit ^= 1;
        }
        spin_unlock(&q->lock);

        write_tx_descs(adapter, skb, pidx, genbit, q);

        /*
         * We always ring the doorbell for cmdQ1.  For cmdQ0, we only ring
         * the doorbell if the Q is asleep. There is a natural race, where
         * the hardware is going to sleep just after we checked, however,
         * then the interrupt handler will detect the outstanding TX packet
         * and ring the doorbell for us.
         */
        if (qid)
                doorbell_pio(adapter, F_CMDQ1_ENABLE);
        else {
                clear_bit(CMDQ_STAT_LAST_PKT_DB, &q->status);
                if (test_and_set_bit(CMDQ_STAT_RUNNING, &q->status) == 0) {
                        set_bit(CMDQ_STAT_LAST_PKT_DB, &q->status);
                        writel(F_CMDQ0_ENABLE, adapter->regs + A_SG_DOORBELL);
                }
        }

        if (use_sched_skb) {
                if (spin_trylock(&q->lock)) {
                        credits = q->size - q->in_use;
                        skb = NULL;
                        goto use_sched;
                }
        }
        return NETDEV_TX_OK;
}

#define MK_ETH_TYPE_MSS(type, mss) (((mss) & 0x3FFF) | ((type) << 14))

/*
 *      eth_hdr_len - return the length of an Ethernet header
 *      @data: pointer to the start of the Ethernet header
 *
 *      Returns the length of an Ethernet header, including optional VLAN tag.
 */
static inline int eth_hdr_len(const void *data)
{
        const struct ethhdr *e = data;

        return e->h_proto == htons(ETH_P_8021Q) ? VLAN_ETH_HLEN : ETH_HLEN;
}

/*
 * Adds the CPL header to the sk_buff and passes it to t1_sge_tx.
 */
int t1_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct adapter *adapter = dev->priv;
        struct sge *sge = adapter->sge;
        struct sge_port_stats *st = per_cpu_ptr(sge->port_stats[dev->if_port], smp_processor_id());
        struct cpl_tx_pkt *cpl;

        if (skb->protocol == htons(ETH_P_CPL5))
                goto send;

        if (skb_shinfo(skb)->gso_size) {
                int eth_type;
                struct cpl_tx_pkt_lso *hdr;

                ++st->tx_tso;

                eth_type = skb->nh.raw - skb->data == ETH_HLEN ?
                        CPL_ETH_II : CPL_ETH_II_VLAN;

                hdr = (struct cpl_tx_pkt_lso *)skb_push(skb, sizeof(*hdr));
                hdr->opcode = CPL_TX_PKT_LSO;
                hdr->ip_csum_dis = hdr->l4_csum_dis = 0;
                hdr->ip_hdr_words = skb->nh.iph->ihl;
                hdr->tcp_hdr_words = skb->h.th->doff;
                hdr->eth_type_mss = htons(MK_ETH_TYPE_MSS(eth_type,
                                                          skb_shinfo(skb)->gso_size));
                hdr->len = htonl(skb->len - sizeof(*hdr));
                cpl = (struct cpl_tx_pkt *)hdr;
        } else {
                /*
                 * Packets shorter than ETH_HLEN can break the MAC, drop them
                 * early.  Also, we may get oversized packets because some
                 * parts of the kernel don't handle our unusual hard_header_len
                 * right, drop those too.
                 */
                if (unlikely(skb->len < ETH_HLEN ||
                             skb->len > dev->mtu + eth_hdr_len(skb->data))) {
                        pr_debug("%s: packet size %d hdr %d mtu%d\n", dev->name,
                                 skb->len, eth_hdr_len(skb->data), dev->mtu);
                        dev_kfree_skb_any(skb);
                        return NETDEV_TX_OK;
                }

                /*
                 * We are using a non-standard hard_header_len and some kernel
                 * components, such as pktgen, do not handle it right.
                 * Complain when this happens but try to fix things up.
                 */
                if (unlikely(skb_headroom(skb) < dev->hard_header_len - ETH_HLEN)) {
                        struct sk_buff *orig_skb = skb;

                        pr_debug("%s: headroom %d header_len %d\n", dev->name,
                                 skb_headroom(skb), dev->hard_header_len);

                        if (net_ratelimit())
                                printk(KERN_ERR "%s: inadequate headroom in "
                                       "Tx packet\n", dev->name);
                        skb = skb_realloc_headroom(skb, sizeof(*cpl));
                        dev_kfree_skb_any(orig_skb);
                        if (!skb)
                                return NETDEV_TX_OK;
                }

                if (!(adapter->flags & UDP_CSUM_CAPABLE) &&
                    skb->ip_summed == CHECKSUM_PARTIAL &&
                    skb->nh.iph->protocol == IPPROTO_UDP) {
                        if (unlikely(skb_checksum_help(skb))) {
                                pr_debug("%s: unable to do udp checksum\n", dev->name);
                                dev_kfree_skb_any(skb);
                                return NETDEV_TX_OK;
                        }
                }

                /* Hmmm, assuming to catch the gratious arp... and we'll use
                 * it to flush out stuck espi packets...
                 */
                if ((unlikely(!adapter->sge->espibug_skb[dev->if_port]))) {
                        if (skb->protocol == htons(ETH_P_ARP) &&
                            skb->nh.arph->ar_op == htons(ARPOP_REQUEST)) {
                                adapter->sge->espibug_skb[dev->if_port] = skb;
                                /* We want to re-use this skb later. We
                                 * simply bump the reference count and it
                                 * will not be freed...
                                 */
                                skb = skb_get(skb);
                        }
                }

                cpl = (struct cpl_tx_pkt *)__skb_push(skb, sizeof(*cpl));
                cpl->opcode = CPL_TX_PKT;
                cpl->ip_csum_dis = 1;    /* SW calculates IP csum */
                cpl->l4_csum_dis = skb->ip_summed == CHECKSUM_PARTIAL ? 0 : 1;
                /* the length field isn't used so don't bother setting it */

                st->tx_cso += (skb->ip_summed == CHECKSUM_PARTIAL);
        }
        cpl->iff = dev->if_port;

#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
        if (adapter->vlan_grp && vlan_tx_tag_present(skb)) {
                cpl->vlan_valid = 1;
                cpl->vlan = htons(vlan_tx_tag_get(skb));
                st->vlan_insert++;
        } else
#endif
                cpl->vlan_valid = 0;

send:
        st->tx_packets++;
        dev->trans_start = jiffies;
        return t1_sge_tx(skb, adapter, 0, dev);
}

/*
 * Callback for the Tx buffer reclaim timer.  Runs with softirqs disabled.
 */
static void sge_tx_reclaim_cb(unsigned long data)
{
        int i;
        struct sge *sge = (struct sge *)data;

        for (i = 0; i < SGE_CMDQ_N; ++i) {
                struct cmdQ *q = &sge->cmdQ[i];

                if (!spin_trylock(&q->lock))
                        continue;

                reclaim_completed_tx(sge, q);
                if (i == 0 && q->in_use) {    /* flush pending credits */
                        writel(F_CMDQ0_ENABLE, sge->adapter->regs + A_SG_DOORBELL);
                }
                spin_unlock(&q->lock);
        }
        mod_timer(&sge->tx_reclaim_timer, jiffies + TX_RECLAIM_PERIOD);
}

/*
 * Propagate changes of the SGE coalescing parameters to the HW.
 */
int t1_sge_set_coalesce_params(struct sge *sge, struct sge_params *p)
{
        sge->netdev->poll = t1_poll;
        sge->fixed_intrtimer = p->rx_coalesce_usecs *
                core_ticks_per_usec(sge->adapter);
        writel(sge->fixed_intrtimer, sge->adapter->regs + A_SG_INTRTIMER);
        return 0;
}

/*
 * Allocates both RX and TX resources and configures the SGE. However,
 * the hardware is not enabled yet.
 */
int t1_sge_configure(struct sge *sge, struct sge_params *p)
{
        if (alloc_rx_resources(sge, p))
                return -ENOMEM;
        if (alloc_tx_resources(sge, p)) {
                free_rx_resources(sge);
                return -ENOMEM;
        }
        configure_sge(sge, p);

        /*
         * Now that we have sized the free lists calculate the payload
         * capacity of the large buffers.  Other parts of the driver use
         * this to set the max offload coalescing size so that RX packets
         * do not overflow our large buffers.
         */
        p->large_buf_capacity = jumbo_payload_capacity(sge);
        return 0;
}

/*
 * Disables the DMA engine.
 */
void t1_sge_stop(struct sge *sge)
{
        int i;
        writel(0, sge->adapter->regs + A_SG_CONTROL);
        readl(sge->adapter->regs + A_SG_CONTROL); /* flush */

        if (is_T2(sge->adapter))
                del_timer_sync(&sge->espibug_timer);

        del_timer_sync(&sge->tx_reclaim_timer);
        if (sge->tx_sched)
                tx_sched_stop(sge);

        for (i = 0; i < MAX_NPORTS; i++)
                if (sge->espibug_skb[i])
                        kfree_skb(sge->espibug_skb[i]);
}

/*
 * Enables the DMA engine.
 */
void t1_sge_start(struct sge *sge)
{
        refill_free_list(sge, &sge->freelQ[0]);
        refill_free_list(sge, &sge->freelQ[1]);

        writel(sge->sge_control, sge->adapter->regs + A_SG_CONTROL);
        doorbell_pio(sge->adapter, F_FL0_ENABLE | F_FL1_ENABLE);
        readl(sge->adapter->regs + A_SG_CONTROL); /* flush */

        mod_timer(&sge->tx_reclaim_timer, jiffies + TX_RECLAIM_PERIOD);

        if (is_T2(sge->adapter))
                mod_timer(&sge->espibug_timer, jiffies + sge->espibug_timeout);
}

/*
 * Callback for the T2 ESPI 'stuck packet feature' workaorund
 */
static void espibug_workaround_t204(unsigned long data)
{
        struct adapter *adapter = (struct adapter *)data;
        struct sge *sge = adapter->sge;
        unsigned int nports = adapter->params.nports;
        u32 seop[MAX_NPORTS];

        if (adapter->open_device_map & PORT_MASK) {
                int i;
                if (t1_espi_get_mon_t204(adapter, &(seop[0]), 0) < 0) {
                        return;
                }
                for (i = 0; i < nports; i++) {
                        struct sk_buff *skb = sge->espibug_skb[i];
                        if ( (netif_running(adapter->port[i].dev)) &&
                             !(netif_queue_stopped(adapter->port[i].dev)) &&
                             (seop[i] && ((seop[i] & 0xfff) == 0)) &&
                             skb ) {
                                if (!skb->cb[0]) {
                                        u8 ch_mac_addr[ETH_ALEN] =
                                        {0x0, 0x7, 0x43, 0x0, 0x0, 0x0};
                                        memcpy(skb->data + sizeof(struct cpl_tx_pkt),
                                        ch_mac_addr, ETH_ALEN);
                                        memcpy(skb->data + skb->len - 10,
                                                ch_mac_addr, ETH_ALEN);
                                        skb->cb[0] = 0xff;
                                }

                                /* bump the reference count to avoid freeing of
                                 * the skb once the DMA has completed.
                                 */
                                skb = skb_get(skb);
                                t1_sge_tx(skb, adapter, 0, adapter->port[i].dev);
                        }
                }
        }
        mod_timer(&sge->espibug_timer, jiffies + sge->espibug_timeout);
}

static void espibug_workaround(unsigned long data)
{
        struct adapter *adapter = (struct adapter *)data;
        struct sge *sge = adapter->sge;

        if (netif_running(adapter->port[0].dev)) {
                struct sk_buff *skb = sge->espibug_skb[0];
                u32 seop = t1_espi_get_mon(adapter, 0x930, 0);

                if ((seop & 0xfff0fff) == 0xfff && skb) {
                        if (!skb->cb[0]) {
                                u8 ch_mac_addr[ETH_ALEN] =
                                    {0x0, 0x7, 0x43, 0x0, 0x0, 0x0};
                                memcpy(skb->data + sizeof(struct cpl_tx_pkt),
                                       ch_mac_addr, ETH_ALEN);
                                memcpy(skb->data + skb->len - 10, ch_mac_addr,
                                       ETH_ALEN);
                                skb->cb[0] = 0xff;
                        }

                        /* bump the reference count to avoid freeing of the
                         * skb once the DMA has completed.
                         */
                        skb = skb_get(skb);
                        t1_sge_tx(skb, adapter, 0, adapter->port[0].dev);
                }
        }
        mod_timer(&sge->espibug_timer, jiffies + sge->espibug_timeout);
}

/*
 * Creates a t1_sge structure and returns suggested resource parameters.
 */
struct sge * __devinit t1_sge_create(struct adapter *adapter,
                                     struct sge_params *p)
{
        struct sge *sge = kzalloc(sizeof(*sge), GFP_KERNEL);
        int i;

        if (!sge)
                return NULL;

        sge->adapter = adapter;
        sge->netdev = adapter->port[0].dev;
        sge->rx_pkt_pad = t1_is_T1B(adapter) ? 0 : 2;
        sge->jumbo_fl = t1_is_T1B(adapter) ? 1 : 0;

        for_each_port(adapter, i) {
                sge->port_stats[i] = alloc_percpu(struct sge_port_stats);
                if (!sge->port_stats[i])
                        goto nomem_port;
        }

        init_timer(&sge->tx_reclaim_timer);
        sge->tx_reclaim_timer.data = (unsigned long)sge;
        sge->tx_reclaim_timer.function = sge_tx_reclaim_cb;

        if (is_T2(sge->adapter)) {
                init_timer(&sge->espibug_timer);

                if (adapter->params.nports > 1) {
                        tx_sched_init(sge);
                        sge->espibug_timer.function = espibug_workaround_t204;
                } else {
                        sge->espibug_timer.function = espibug_workaround;
                }
                sge->espibug_timer.data = (unsigned long)sge->adapter;

                sge->espibug_timeout = 1;
                /* for T204, every 10ms */
                if (adapter->params.nports > 1)
                        sge->espibug_timeout = HZ/100;
        }
         

        p->cmdQ_size[0] = SGE_CMDQ0_E_N;
        p->cmdQ_size[1] = SGE_CMDQ1_E_N;
        p->freelQ_size[!sge->jumbo_fl] = SGE_FREEL_SIZE;
        p->freelQ_size[sge->jumbo_fl] = SGE_JUMBO_FREEL_SIZE;
        if (sge->tx_sched) {
                if (board_info(sge->adapter)->board == CHBT_BOARD_CHT204)
                        p->rx_coalesce_usecs = 15;
                else
                        p->rx_coalesce_usecs = 50;
        } else
                p->rx_coalesce_usecs = 50;

        p->coalesce_enable = 0;
        p->sample_interval_usecs = 0;
        p->polling = 0;

        return sge;
nomem_port:
        while (i >= 0) {
                free_percpu(sge->port_stats[i]);
                --i;
        }
        kfree(sge);
        return NULL;

}