// SPDX-License-Identifier: GPL-2.0-or-later
/*      FarSync WAN driver for Linux (2.6.x kernel version)
 *
 *      Actually sync driver for X.21, V.35 and V.24 on FarSync T-series cards
 *
 *      Copyright (C) 2001-2004 FarSite Communications Ltd.
 *      www.farsite.co.uk
 *
 *      Author:      R.J.Dunlop    <bob.dunlop@farsite.co.uk>
 *      Maintainer:  Kevin Curtis  <kevin.curtis@farsite.co.uk>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/version.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/if.h>
#include <linux/hdlc.h>
#include <asm/io.h>
#include <linux/uaccess.h>

#include "farsync.h"

/*      Module info
 */
MODULE_AUTHOR("R.J.Dunlop <bob.dunlop@farsite.co.uk>");
MODULE_DESCRIPTION("FarSync T-Series WAN driver. FarSite Communications Ltd.");
MODULE_LICENSE("GPL");

/*      Driver configuration and global parameters
 *      ==========================================
 */

/*      Number of ports (per card) and cards supported
 */
#define FST_MAX_PORTS           4
#define FST_MAX_CARDS           32

/*      Default parameters for the link
 */
#define FST_TX_QUEUE_LEN        100     /* At 8Mbps a longer queue length is
                                         * useful
                                         */
#define FST_TXQ_DEPTH           16      /* This one is for the buffering
                                         * of frames on the way down to the card
                                         * so that we can keep the card busy
                                         * and maximise throughput
                                         */
#define FST_HIGH_WATER_MARK     12      /* Point at which we flow control
                                         * network layer
                                         */
#define FST_LOW_WATER_MARK      8       /* Point at which we remove flow
                                         * control from network layer
                                         */
#define FST_MAX_MTU             8000    /* Huge but possible */
#define FST_DEF_MTU             1500    /* Common sane value */

#define FST_TX_TIMEOUT          (2 * HZ)

#ifdef ARPHRD_RAWHDLC
#define ARPHRD_MYTYPE   ARPHRD_RAWHDLC  /* Raw frames */
#else
#define ARPHRD_MYTYPE   ARPHRD_HDLC     /* Cisco-HDLC (keepalives etc) */
#endif

/* Modules parameters and associated variables
 */
static int fst_txq_low = FST_LOW_WATER_MARK;
static int fst_txq_high = FST_HIGH_WATER_MARK;
static int fst_max_reads = 7;
static int fst_excluded_cards;
static int fst_excluded_list[FST_MAX_CARDS];

module_param(fst_txq_low, int, 0);
module_param(fst_txq_high, int, 0);
module_param(fst_max_reads, int, 0);
module_param(fst_excluded_cards, int, 0);
module_param_array(fst_excluded_list, int, NULL, 0);

/*      Card shared memory layout
 *      =========================
 */
#pragma pack(1)

/*      This information is derived in part from the FarSite FarSync Smc.h
 *      file. Unfortunately various name clashes and the non-portability of the
 *      bit field declarations in that file have meant that I have chosen to
 *      recreate the information here.
 *
 *      The SMC (Shared Memory Configuration) has a version number that is
 *      incremented every time there is a significant change. This number can
 *      be used to check that we have not got out of step with the firmware
 *      contained in the .CDE files.
 */
#define SMC_VERSION 24

#define FST_MEMSIZE 0x100000    /* Size of card memory (1Mb) */

#define SMC_BASE 0x00002000L    /* Base offset of the shared memory window main
                                 * configuration structure
                                 */
#define BFM_BASE 0x00010000L    /* Base offset of the shared memory window DMA
                                 * buffers
                                 */

#define LEN_TX_BUFFER 8192      /* Size of packet buffers */
#define LEN_RX_BUFFER 8192

#define LEN_SMALL_TX_BUFFER 256 /* Size of obsolete buffs used for DOS diags */
#define LEN_SMALL_RX_BUFFER 256

#define NUM_TX_BUFFER 2         /* Must be power of 2. Fixed by firmware */
#define NUM_RX_BUFFER 8

/* Interrupt retry time in milliseconds */
#define INT_RETRY_TIME 2

/*      The Am186CH/CC processors support a SmartDMA mode using circular pools
 *      of buffer descriptors. The structure is almost identical to that used
 *      in the LANCE Ethernet controllers. Details available as PDF from the
 *      AMD web site: https://www.amd.com/products/epd/processors/\
 *                    2.16bitcont/3.am186cxfa/a21914/21914.pdf
 */
struct txdesc {                 /* Transmit descriptor */
        volatile u16 ladr;      /* Low order address of packet. This is a
                                 * linear address in the Am186 memory space
                                 */
        volatile u8 hadr;       /* High order address. Low 4 bits only, high 4
                                 * bits must be zero
                                 */
        volatile u8 bits;       /* Status and config */
        volatile u16 bcnt;      /* 2s complement of packet size in low 15 bits.
                                 * Transmit terminal count interrupt enable in
                                 * top bit.
                                 */
        u16 unused;             /* Not used in Tx */
};

struct rxdesc {                 /* Receive descriptor */
        volatile u16 ladr;      /* Low order address of packet */
        volatile u8 hadr;       /* High order address */
        volatile u8 bits;       /* Status and config */
        volatile u16 bcnt;      /* 2s complement of buffer size in low 15 bits.
                                 * Receive terminal count interrupt enable in
                                 * top bit.
                                 */
        volatile u16 mcnt;      /* Message byte count (15 bits) */
};

/* Convert a length into the 15 bit 2's complement */
/* #define cnv_bcnt(len)   (( ~(len) + 1 ) & 0x7FFF ) */
/* Since we need to set the high bit to enable the completion interrupt this
 * can be made a lot simpler
 */
#define cnv_bcnt(len)   (-(len))

/* Status and config bits for the above */
#define DMA_OWN         0x80    /* SmartDMA owns the descriptor */
#define TX_STP          0x02    /* Tx: start of packet */
#define TX_ENP          0x01    /* Tx: end of packet */
#define RX_ERR          0x40    /* Rx: error (OR of next 4 bits) */
#define RX_FRAM         0x20    /* Rx: framing error */
#define RX_OFLO         0x10    /* Rx: overflow error */
#define RX_CRC          0x08    /* Rx: CRC error */
#define RX_HBUF         0x04    /* Rx: buffer error */
#define RX_STP          0x02    /* Rx: start of packet */
#define RX_ENP          0x01    /* Rx: end of packet */

/* Interrupts from the card are caused by various events which are presented
 * in a circular buffer as several events may be processed on one physical int
 */
#define MAX_CIRBUFF     32

struct cirbuff {
        u8 rdindex;             /* read, then increment and wrap */
        u8 wrindex;             /* write, then increment and wrap */
        u8 evntbuff[MAX_CIRBUFF];
};

/* Interrupt event codes.
 * Where appropriate the two low order bits indicate the port number
 */
#define CTLA_CHG        0x18    /* Control signal changed */
#define CTLB_CHG        0x19
#define CTLC_CHG        0x1A
#define CTLD_CHG        0x1B

#define INIT_CPLT       0x20    /* Initialisation complete */
#define INIT_FAIL       0x21    /* Initialisation failed */

#define ABTA_SENT       0x24    /* Abort sent */
#define ABTB_SENT       0x25
#define ABTC_SENT       0x26
#define ABTD_SENT       0x27

#define TXA_UNDF        0x28    /* Transmission underflow */
#define TXB_UNDF        0x29
#define TXC_UNDF        0x2A
#define TXD_UNDF        0x2B

#define F56_INT         0x2C
#define M32_INT         0x2D

#define TE1_ALMA        0x30

/* Port physical configuration. See farsync.h for field values */
struct port_cfg {
        u16 lineInterface;      /* Physical interface type */
        u8 x25op;               /* Unused at present */
        u8 internalClock;       /* 1 => internal clock, 0 => external */
        u8 transparentMode;     /* 1 => on, 0 => off */
        u8 invertClock;         /* 0 => normal, 1 => inverted */
        u8 padBytes[6];         /* Padding */
        u32 lineSpeed;          /* Speed in bps */
};

/* TE1 port physical configuration */
struct su_config {
        u32 dataRate;
        u8 clocking;
        u8 framing;
        u8 structure;
        u8 interface;
        u8 coding;
        u8 lineBuildOut;
        u8 equalizer;
        u8 transparentMode;
        u8 loopMode;
        u8 range;
        u8 txBufferMode;
        u8 rxBufferMode;
        u8 startingSlot;
        u8 losThreshold;
        u8 enableIdleCode;
        u8 idleCode;
        u8 spare[44];
};

/* TE1 Status */
struct su_status {
        u32 receiveBufferDelay;
        u32 framingErrorCount;
        u32 codeViolationCount;
        u32 crcErrorCount;
        u32 lineAttenuation;
        u8 portStarted;
        u8 lossOfSignal;
        u8 receiveRemoteAlarm;
        u8 alarmIndicationSignal;
        u8 spare[40];
};

/* Finally sling all the above together into the shared memory structure.
 * Sorry it's a hodge podge of arrays, structures and unused bits, it's been
 * evolving under NT for some time so I guess we're stuck with it.
 * The structure starts at offset SMC_BASE.
 * See farsync.h for some field values.
 */
struct fst_shared {
        /* DMA descriptor rings */
        struct rxdesc rxDescrRing[FST_MAX_PORTS][NUM_RX_BUFFER];
        struct txdesc txDescrRing[FST_MAX_PORTS][NUM_TX_BUFFER];

        /* Obsolete small buffers */
        u8 smallRxBuffer[FST_MAX_PORTS][NUM_RX_BUFFER][LEN_SMALL_RX_BUFFER];
        u8 smallTxBuffer[FST_MAX_PORTS][NUM_TX_BUFFER][LEN_SMALL_TX_BUFFER];

        u8 taskStatus;          /* 0x00 => initialising, 0x01 => running,
                                 * 0xFF => halted
                                 */

        u8 interruptHandshake;  /* Set to 0x01 by adapter to signal interrupt,
                                 * set to 0xEE by host to acknowledge interrupt
                                 */

        u16 smcVersion;         /* Must match SMC_VERSION */

        u32 smcFirmwareVersion; /* 0xIIVVRRBB where II = product ID, VV = major
                                 * version, RR = revision and BB = build
                                 */

        u16 txa_done;           /* Obsolete completion flags */
        u16 rxa_done;
        u16 txb_done;
        u16 rxb_done;
        u16 txc_done;
        u16 rxc_done;
        u16 txd_done;
        u16 rxd_done;

        u16 mailbox[4];         /* Diagnostics mailbox. Not used */

        struct cirbuff interruptEvent;  /* interrupt causes */

        u32 v24IpSts[FST_MAX_PORTS];    /* V.24 control input status */
        u32 v24OpSts[FST_MAX_PORTS];    /* V.24 control output status */

        struct port_cfg portConfig[FST_MAX_PORTS];

        u16 clockStatus[FST_MAX_PORTS]; /* lsb: 0=> present, 1=> absent */

        u16 cableStatus;        /* lsb: 0=> present, 1=> absent */

        u16 txDescrIndex[FST_MAX_PORTS];        /* transmit descriptor ring index */
        u16 rxDescrIndex[FST_MAX_PORTS];        /* receive descriptor ring index */

        u16 portMailbox[FST_MAX_PORTS][2];      /* command, modifier */
        u16 cardMailbox[4];     /* Not used */

        /* Number of times the card thinks the host has
         * missed an interrupt by not acknowledging
         * within 2mS (I guess NT has problems)
         */
        u32 interruptRetryCount;

        /* Driver private data used as an ID. We'll not
         * use this as I'd rather keep such things
         * in main memory rather than on the PCI bus
         */
        u32 portHandle[FST_MAX_PORTS];

        /* Count of Tx underflows for stats */
        u32 transmitBufferUnderflow[FST_MAX_PORTS];

        /* Debounced V.24 control input status */
        u32 v24DebouncedSts[FST_MAX_PORTS];

        /* Adapter debounce timers. Don't touch */
        u32 ctsTimer[FST_MAX_PORTS];
        u32 ctsTimerRun[FST_MAX_PORTS];
        u32 dcdTimer[FST_MAX_PORTS];
        u32 dcdTimerRun[FST_MAX_PORTS];

        u32 numberOfPorts;      /* Number of ports detected at startup */

        u16 _reserved[64];

        u16 cardMode;           /* Bit-mask to enable features:
                                 * Bit 0: 1 enables LED identify mode
                                 */

        u16 portScheduleOffset;

        struct su_config suConfig;      /* TE1 Bits */
        struct su_status suStatus;

        u32 endOfSmcSignature;  /* endOfSmcSignature MUST be the last member of
                                 * the structure and marks the end of shared
                                 * memory. Adapter code initializes it as
                                 * END_SIG.
                                 */
};

/* endOfSmcSignature value */
#define END_SIG                 0x12345678

/* Mailbox values. (portMailbox) */
#define NOP             0       /* No operation */
#define ACK             1       /* Positive acknowledgement to PC driver */
#define NAK             2       /* Negative acknowledgement to PC driver */
#define STARTPORT       3       /* Start an HDLC port */
#define STOPPORT        4       /* Stop an HDLC port */
#define ABORTTX         5       /* Abort the transmitter for a port */
#define SETV24O         6       /* Set V24 outputs */

/* PLX Chip Register Offsets */
#define CNTRL_9052      0x50    /* Control Register */
#define CNTRL_9054      0x6c    /* Control Register */

#define INTCSR_9052     0x4c    /* Interrupt control/status register */
#define INTCSR_9054     0x68    /* Interrupt control/status register */

/* 9054 DMA Registers */
/* Note that we will be using DMA Channel 0 for copying rx data
 * and Channel 1 for copying tx data
 */
#define DMAMODE0        0x80
#define DMAPADR0        0x84
#define DMALADR0        0x88
#define DMASIZ0         0x8c
#define DMADPR0         0x90
#define DMAMODE1        0x94
#define DMAPADR1        0x98
#define DMALADR1        0x9c
#define DMASIZ1         0xa0
#define DMADPR1         0xa4
#define DMACSR0         0xa8
#define DMACSR1         0xa9
#define DMAARB          0xac
#define DMATHR          0xb0
#define DMADAC0         0xb4
#define DMADAC1         0xb8
#define DMAMARBR        0xac

#define FST_MIN_DMA_LEN 64
#define FST_RX_DMA_INT  0x01
#define FST_TX_DMA_INT  0x02
#define FST_CARD_INT    0x04

/* Larger buffers are positioned in memory at offset BFM_BASE */
struct buf_window {
        u8 txBuffer[FST_MAX_PORTS][NUM_TX_BUFFER][LEN_TX_BUFFER];
        u8 rxBuffer[FST_MAX_PORTS][NUM_RX_BUFFER][LEN_RX_BUFFER];
};

/* Calculate offset of a buffer object within the shared memory window */
#define BUF_OFFSET(X)   (BFM_BASE + offsetof(struct buf_window, X))

#pragma pack()

/*      Device driver private information
 *      =================================
 */
/*      Per port (line or channel) information
 */
struct fst_port_info {
        struct net_device *dev; /* Device struct - must be first */
        struct fst_card_info *card;     /* Card we're associated with */
        int index;              /* Port index on the card */
        int hwif;               /* Line hardware (lineInterface copy) */
        int run;                /* Port is running */
        int mode;               /* Normal or FarSync raw */
        int rxpos;              /* Next Rx buffer to use */
        int txpos;              /* Next Tx buffer to use */
        int txipos;             /* Next Tx buffer to check for free */
        int start;              /* Indication of start/stop to network */
        /* A sixteen entry transmit queue
         */
        int txqs;               /* index to get next buffer to tx */
        int txqe;               /* index to queue next packet */
        struct sk_buff *txq[FST_TXQ_DEPTH];     /* The queue */
        int rxqdepth;
};

/*      Per card information
 */
struct fst_card_info {
        char __iomem *mem;      /* Card memory mapped to kernel space */
        char __iomem *ctlmem;   /* Control memory for PCI cards */
        unsigned int phys_mem;  /* Physical memory window address */
        unsigned int phys_ctlmem;       /* Physical control memory address */
        unsigned int irq;       /* Interrupt request line number */
        unsigned int nports;    /* Number of serial ports */
        unsigned int type;      /* Type index of card */
        unsigned int state;     /* State of card */
        spinlock_t card_lock;   /* Lock for SMP access */
        unsigned short pci_conf;        /* PCI card config in I/O space */
        /* Per port info */
        struct fst_port_info ports[FST_MAX_PORTS];
        struct pci_dev *device; /* Information about the pci device */
        int card_no;            /* Inst of the card on the system */
        int family;             /* TxP or TxU */
        int dmarx_in_progress;
        int dmatx_in_progress;
        unsigned long int_count;
        unsigned long int_time_ave;
        void *rx_dma_handle_host;
        dma_addr_t rx_dma_handle_card;
        void *tx_dma_handle_host;
        dma_addr_t tx_dma_handle_card;
        struct sk_buff *dma_skb_rx;
        struct fst_port_info *dma_port_rx;
        struct fst_port_info *dma_port_tx;
        int dma_len_rx;
        int dma_len_tx;
        int dma_txpos;
        int dma_rxpos;
};

/* Convert an HDLC device pointer into a port info pointer and similar */
#define dev_to_port(D)  (dev_to_hdlc(D)->priv)
#define port_to_dev(P)  ((P)->dev)

/*      Shared memory window access macros
 *
 *      We have a nice memory based structure above, which could be directly
 *      mapped on i386 but might not work on other architectures unless we use
 *      the readb,w,l and writeb,w,l macros. Unfortunately these macros take
 *      physical offsets so we have to convert. The only saving grace is that
 *      this should all collapse back to a simple indirection eventually.
 */
#define WIN_OFFSET(X)   ((long)&(((struct fst_shared *)SMC_BASE)->X))

#define FST_RDB(C, E)    (readb((C)->mem + WIN_OFFSET(E)))
#define FST_RDW(C, E)    (readw((C)->mem + WIN_OFFSET(E)))
#define FST_RDL(C, E)    (readl((C)->mem + WIN_OFFSET(E)))

#define FST_WRB(C, E, B)  (writeb((B), (C)->mem + WIN_OFFSET(E)))
#define FST_WRW(C, E, W)  (writew((W), (C)->mem + WIN_OFFSET(E)))
#define FST_WRL(C, E, L)  (writel((L), (C)->mem + WIN_OFFSET(E)))

/*      Debug support
 */
#if FST_DEBUG

static int fst_debug_mask = { FST_DEBUG };

/* Most common debug activity is to print something if the corresponding bit
 * is set in the debug mask. Note: this uses a non-ANSI extension in GCC to
 * support variable numbers of macro parameters. The inverted if prevents us
 * eating someone else's else clause.
 */
#define dbg(F, fmt, args...)                                    \
do {                                                            \
        if (fst_debug_mask & (F))                               \
                printk(KERN_DEBUG pr_fmt(fmt), ##args);         \
} while (0)
#else
#define dbg(F, fmt, args...)                                    \
do {                                                            \
        if (0)                                                  \
                printk(KERN_DEBUG pr_fmt(fmt), ##args);         \
} while (0)
#endif

/*      PCI ID lookup table
 */
static const struct pci_device_id fst_pci_dev_id[] = {
        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_T2P, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_T2P},

        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_T4P, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_T4P},

        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_T1U, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_T1U},

        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_T2U, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_T2U},

        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_T4U, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_T4U},

        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_TE1, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_TE1},

        {PCI_VENDOR_ID_FARSITE, PCI_DEVICE_ID_FARSITE_TE1C, PCI_ANY_ID,
         PCI_ANY_ID, 0, 0, FST_TYPE_TE1},
        {0,}                    /* End */
};

MODULE_DEVICE_TABLE(pci, fst_pci_dev_id);

/*      Device Driver Work Queues
 *
 *      So that we don't spend too much time processing events in the
 *      Interrupt Service routine, we will declare a work queue per Card
 *      and make the ISR schedule a task in the queue for later execution.
 *      In the 2.4 Kernel we used to use the immediate queue for BH's
 *      Now that they are gone, tasklets seem to be much better than work
 *      queues.
 */

static void do_bottom_half_tx(struct fst_card_info *card);
static void do_bottom_half_rx(struct fst_card_info *card);
static void fst_process_tx_work_q(struct tasklet_struct *unused);
static void fst_process_int_work_q(struct tasklet_struct *unused);

static DECLARE_TASKLET(fst_tx_task, fst_process_tx_work_q);
static DECLARE_TASKLET(fst_int_task, fst_process_int_work_q);

static struct fst_card_info *fst_card_array[FST_MAX_CARDS];
static DEFINE_SPINLOCK(fst_work_q_lock);
static u64 fst_work_txq;
static u64 fst_work_intq;

static void
fst_q_work_item(u64 *queue, int card_index)
{
        unsigned long flags;
        u64 mask;

        /* Grab the queue exclusively
         */
        spin_lock_irqsave(&fst_work_q_lock, flags);

        /* Making an entry in the queue is simply a matter of setting
         * a bit for the card indicating that there is work to do in the
         * bottom half for the card.  Note the limitation of 64 cards.
         * That ought to be enough
         */
        mask = (u64)1 << card_index;
        *queue |= mask;
        spin_unlock_irqrestore(&fst_work_q_lock, flags);
}

static void
fst_process_tx_work_q(struct tasklet_struct *unused)
{
        unsigned long flags;
        u64 work_txq;
        int i;

        /* Grab the queue exclusively
         */
        dbg(DBG_TX, "fst_process_tx_work_q\n");
        spin_lock_irqsave(&fst_work_q_lock, flags);
        work_txq = fst_work_txq;
        fst_work_txq = 0;
        spin_unlock_irqrestore(&fst_work_q_lock, flags);

        /* Call the bottom half for each card with work waiting
         */
        for (i = 0; i < FST_MAX_CARDS; i++) {
                if (work_txq & 0x01) {
                        if (fst_card_array[i]) {
                                dbg(DBG_TX, "Calling tx bh for card %d\n", i);
                                do_bottom_half_tx(fst_card_array[i]);
                        }
                }
                work_txq = work_txq >> 1;
        }
}

static void
fst_process_int_work_q(struct tasklet_struct *unused)
{
        unsigned long flags;
        u64 work_intq;
        int i;

        /* Grab the queue exclusively
         */
        dbg(DBG_INTR, "fst_process_int_work_q\n");
        spin_lock_irqsave(&fst_work_q_lock, flags);
        work_intq = fst_work_intq;
        fst_work_intq = 0;
        spin_unlock_irqrestore(&fst_work_q_lock, flags);

        /* Call the bottom half for each card with work waiting
         */
        for (i = 0; i < FST_MAX_CARDS; i++) {
                if (work_intq & 0x01) {
                        if (fst_card_array[i]) {
                                dbg(DBG_INTR,
                                    "Calling rx & tx bh for card %d\n", i);
                                do_bottom_half_rx(fst_card_array[i]);
                                do_bottom_half_tx(fst_card_array[i]);
                        }
                }
                work_intq = work_intq >> 1;
        }
}

/*      Card control functions
 *      ======================
 */
/*      Place the processor in reset state
 *
 * Used to be a simple write to card control space but a glitch in the latest
 * AMD Am186CH processor means that we now have to do it by asserting and de-
 * asserting the PLX chip PCI Adapter Software Reset. Bit 30 in CNTRL register
 * at offset 9052_CNTRL.  Note the updates for the TXU.
 */
static inline void
fst_cpureset(struct fst_card_info *card)
{
        unsigned char interrupt_line_register;
        unsigned int regval;

        if (card->family == FST_FAMILY_TXU) {
                if (pci_read_config_byte
                    (card->device, PCI_INTERRUPT_LINE, &interrupt_line_register)) {
                        dbg(DBG_ASS,
                            "Error in reading interrupt line register\n");
                }
                /* Assert PLX software reset and Am186 hardware reset
                 * and then deassert the PLX software reset but 186 still in reset
                 */
                outw(0x440f, card->pci_conf + CNTRL_9054 + 2);
                outw(0x040f, card->pci_conf + CNTRL_9054 + 2);
                /* We are delaying here to allow the 9054 to reset itself
                 */
                usleep_range(10, 20);
                outw(0x240f, card->pci_conf + CNTRL_9054 + 2);
                /* We are delaying here to allow the 9054 to reload its eeprom
                 */
                usleep_range(10, 20);
                outw(0x040f, card->pci_conf + CNTRL_9054 + 2);

                if (pci_write_config_byte
                    (card->device, PCI_INTERRUPT_LINE, interrupt_line_register)) {
                        dbg(DBG_ASS,
                            "Error in writing interrupt line register\n");
                }

        } else {
                regval = inl(card->pci_conf + CNTRL_9052);

                outl(regval | 0x40000000, card->pci_conf + CNTRL_9052);
                outl(regval & ~0x40000000, card->pci_conf + CNTRL_9052);
        }
}

/*      Release the processor from reset
 */
static inline void
fst_cpurelease(struct fst_card_info *card)
{
        if (card->family == FST_FAMILY_TXU) {
                /* Force posted writes to complete
                 */
                (void)readb(card->mem);

                /* Release LRESET DO = 1
                 * Then release Local Hold, DO = 1
                 */
                outw(0x040e, card->pci_conf + CNTRL_9054 + 2);
                outw(0x040f, card->pci_conf + CNTRL_9054 + 2);
        } else {
                (void)readb(card->ctlmem);
        }
}

/*      Clear the cards interrupt flag
 */
static inline void
fst_clear_intr(struct fst_card_info *card)
{
        if (card->family == FST_FAMILY_TXU) {
                (void)readb(card->ctlmem);
        } else {
                /* Poke the appropriate PLX chip register (same as enabling interrupts)
                 */
                outw(0x0543, card->pci_conf + INTCSR_9052);
        }
}

/*      Enable card interrupts
 */
static inline void
fst_enable_intr(struct fst_card_info *card)
{
        if (card->family == FST_FAMILY_TXU)
                outl(0x0f0c0900, card->pci_conf + INTCSR_9054);
        else
                outw(0x0543, card->pci_conf + INTCSR_9052);
}

/*      Disable card interrupts
 */
static inline void
fst_disable_intr(struct fst_card_info *card)
{
        if (card->family == FST_FAMILY_TXU)
                outl(0x00000000, card->pci_conf + INTCSR_9054);
        else
                outw(0x0000, card->pci_conf + INTCSR_9052);
}

/*      Process the result of trying to pass a received frame up the stack
 */
static void
fst_process_rx_status(int rx_status, char *name)
{
        switch (rx_status) {
        case NET_RX_SUCCESS:
                {
                        /* Nothing to do here
                         */
                        break;
                }
        case NET_RX_DROP:
                {
                        dbg(DBG_ASS, "%s: Received packet dropped\n", name);
                        break;
                }
        }
}

/*      Initilaise DMA for PLX 9054
 */
static inline void
fst_init_dma(struct fst_card_info *card)
{
        /* This is only required for the PLX 9054
         */
        if (card->family == FST_FAMILY_TXU) {
                pci_set_master(card->device);
                outl(0x00020441, card->pci_conf + DMAMODE0);
                outl(0x00020441, card->pci_conf + DMAMODE1);
                outl(0x0, card->pci_conf + DMATHR);
        }
}

/*      Tx dma complete interrupt
 */
static void
fst_tx_dma_complete(struct fst_card_info *card, struct fst_port_info *port,
                    int len, int txpos)
{
        struct net_device *dev = port_to_dev(port);

        /* Everything is now set, just tell the card to go
         */
        dbg(DBG_TX, "fst_tx_dma_complete\n");
        FST_WRB(card, txDescrRing[port->index][txpos].bits,
                DMA_OWN | TX_STP | TX_ENP);
        dev->stats.tx_packets++;
        dev->stats.tx_bytes += len;
        netif_trans_update(dev);
}

/* Mark it for our own raw sockets interface
 */
static __be16 farsync_type_trans(struct sk_buff *skb, struct net_device *dev)
{
        skb->dev = dev;
        skb_reset_mac_header(skb);
        skb->pkt_type = PACKET_HOST;
        return htons(ETH_P_CUST);
}

/*      Rx dma complete interrupt
 */
static void
fst_rx_dma_complete(struct fst_card_info *card, struct fst_port_info *port,
                    int len, struct sk_buff *skb, int rxp)
{
        struct net_device *dev = port_to_dev(port);
        int pi;
        int rx_status;

        dbg(DBG_TX, "fst_rx_dma_complete\n");
        pi = port->index;
        skb_put_data(skb, card->rx_dma_handle_host, len);

        /* Reset buffer descriptor */
        FST_WRB(card, rxDescrRing[pi][rxp].bits, DMA_OWN);

        /* Update stats */
        dev->stats.rx_packets++;
        dev->stats.rx_bytes += len;

        /* Push upstream */
        dbg(DBG_RX, "Pushing the frame up the stack\n");
        if (port->mode == FST_RAW)
                skb->protocol = farsync_type_trans(skb, dev);
        else
                skb->protocol = hdlc_type_trans(skb, dev);
        rx_status = netif_rx(skb);
        fst_process_rx_status(rx_status, port_to_dev(port)->name);
        if (rx_status == NET_RX_DROP)
                dev->stats.rx_dropped++;
}

/*      Receive a frame through the DMA
 */
static inline void
fst_rx_dma(struct fst_card_info *card, dma_addr_t dma, u32 mem, int len)
{
        /* This routine will setup the DMA and start it
         */

        dbg(DBG_RX, "In fst_rx_dma %x %x %d\n", (u32)dma, mem, len);
        if (card->dmarx_in_progress)
                dbg(DBG_ASS, "In fst_rx_dma while dma in progress\n");

        outl(dma, card->pci_conf + DMAPADR0);   /* Copy to here */
        outl(mem, card->pci_conf + DMALADR0);   /* from here */
        outl(len, card->pci_conf + DMASIZ0);    /* for this length */
        outl(0x00000000c, card->pci_conf + DMADPR0);    /* In this direction */

        /* We use the dmarx_in_progress flag to flag the channel as busy
         */
        card->dmarx_in_progress = 1;
        outb(0x03, card->pci_conf + DMACSR0);   /* Start the transfer */
}

/*      Send a frame through the DMA
 */
static inline void
fst_tx_dma(struct fst_card_info *card, dma_addr_t dma, u32 mem, int len)
{
        /* This routine will setup the DMA and start it.
         */

        dbg(DBG_TX, "In fst_tx_dma %x %x %d\n", (u32)dma, mem, len);
        if (card->dmatx_in_progress)
                dbg(DBG_ASS, "In fst_tx_dma while dma in progress\n");

        outl(dma, card->pci_conf + DMAPADR1);   /* Copy from here */
        outl(mem, card->pci_conf + DMALADR1);   /* to here */
        outl(len, card->pci_conf + DMASIZ1);    /* for this length */
        outl(0x000000004, card->pci_conf + DMADPR1);    /* In this direction */

        /* We use the dmatx_in_progress to flag the channel as busy
         */
        card->dmatx_in_progress = 1;
        outb(0x03, card->pci_conf + DMACSR1);   /* Start the transfer */
}

/*      Issue a Mailbox command for a port.
 *      Note we issue them on a fire and forget basis, not expecting to see an
 *      error and not waiting for completion.
 */
static void
fst_issue_cmd(struct fst_port_info *port, unsigned short cmd)
{
        struct fst_card_info *card;
        unsigned short mbval;
        unsigned long flags;
        int safety;

        card = port->card;
        spin_lock_irqsave(&card->card_lock, flags);
        mbval = FST_RDW(card, portMailbox[port->index][0]);

        safety = 0;
        /* Wait for any previous command to complete */
        while (mbval > NAK) {
                spin_unlock_irqrestore(&card->card_lock, flags);
                schedule_timeout_uninterruptible(1);
                spin_lock_irqsave(&card->card_lock, flags);

                if (++safety > 2000) {
                        pr_err("Mailbox safety timeout\n");
                        break;
                }

                mbval = FST_RDW(card, portMailbox[port->index][0]);
        }
        if (safety > 0)
                dbg(DBG_CMD, "Mailbox clear after %d jiffies\n", safety);

        if (mbval == NAK)
                dbg(DBG_CMD, "issue_cmd: previous command was NAK'd\n");

        FST_WRW(card, portMailbox[port->index][0], cmd);

        if (cmd == ABORTTX || cmd == STARTPORT) {
                port->txpos = 0;
                port->txipos = 0;
                port->start = 0;
        }

        spin_unlock_irqrestore(&card->card_lock, flags);
}

/*      Port output signals control
 */
static inline void
fst_op_raise(struct fst_port_info *port, unsigned int outputs)
{
        outputs |= FST_RDL(port->card, v24OpSts[port->index]);
        FST_WRL(port->card, v24OpSts[port->index], outputs);

        if (port->run)
                fst_issue_cmd(port, SETV24O);
}

static inline void
fst_op_lower(struct fst_port_info *port, unsigned int outputs)
{
        outputs = ~outputs & FST_RDL(port->card, v24OpSts[port->index]);
        FST_WRL(port->card, v24OpSts[port->index], outputs);

        if (port->run)
                fst_issue_cmd(port, SETV24O);
}

/*      Setup port Rx buffers
 */
static void
fst_rx_config(struct fst_port_info *port)
{
        int i;
        int pi;
        unsigned int offset;
        unsigned long flags;
        struct fst_card_info *card;

        pi = port->index;
        card = port->card;
        spin_lock_irqsave(&card->card_lock, flags);
        for (i = 0; i < NUM_RX_BUFFER; i++) {
                offset = BUF_OFFSET(rxBuffer[pi][i][0]);

                FST_WRW(card, rxDescrRing[pi][i].ladr, (u16)offset);
                FST_WRB(card, rxDescrRing[pi][i].hadr, (u8)(offset >> 16));
                FST_WRW(card, rxDescrRing[pi][i].bcnt, cnv_bcnt(LEN_RX_BUFFER));
                FST_WRW(card, rxDescrRing[pi][i].mcnt, LEN_RX_BUFFER);
                FST_WRB(card, rxDescrRing[pi][i].bits, DMA_OWN);
        }
        port->rxpos = 0;
        spin_unlock_irqrestore(&card->card_lock, flags);
}

/*      Setup port Tx buffers
 */
static void
fst_tx_config(struct fst_port_info *port)
{
        int i;
        int pi;
        unsigned int offset;
        unsigned long flags;
        struct fst_card_info *card;

        pi = port->index;
        card = port->card;
        spin_lock_irqsave(&card->card_lock, flags);
        for (i = 0; i < NUM_TX_BUFFER; i++) {
                offset = BUF_OFFSET(txBuffer[pi][i][0]);

                FST_WRW(card, txDescrRing[pi][i].ladr, (u16)offset);
                FST_WRB(card, txDescrRing[pi][i].hadr, (u8)(offset >> 16));
                FST_WRW(card, txDescrRing[pi][i].bcnt, 0);
                FST_WRB(card, txDescrRing[pi][i].bits, 0);
        }
        port->txpos = 0;
        port->txipos = 0;
        port->start = 0;
        spin_unlock_irqrestore(&card->card_lock, flags);
}

/*      TE1 Alarm change interrupt event
 */
static void
fst_intr_te1_alarm(struct fst_card_info *card, struct fst_port_info *port)
{
        u8 los;
        u8 rra;
        u8 ais;

        los = FST_RDB(card, suStatus.lossOfSignal);
        rra = FST_RDB(card, suStatus.receiveRemoteAlarm);
        ais = FST_RDB(card, suStatus.alarmIndicationSignal);

        if (los) {
                /* Lost the link
                 */
                if (netif_carrier_ok(port_to_dev(port))) {
                        dbg(DBG_INTR, "Net carrier off\n");
                        netif_carrier_off(port_to_dev(port));
                }
        } else {
                /* Link available
                 */
                if (!netif_carrier_ok(port_to_dev(port))) {
                        dbg(DBG_INTR, "Net carrier on\n");
                        netif_carrier_on(port_to_dev(port));
                }
        }

        if (los)
                dbg(DBG_INTR, "Assert LOS Alarm\n");
        else
                dbg(DBG_INTR, "De-assert LOS Alarm\n");
        if (rra)
                dbg(DBG_INTR, "Assert RRA Alarm\n");
        else
                dbg(DBG_INTR, "De-assert RRA Alarm\n");

        if (ais)
                dbg(DBG_INTR, "Assert AIS Alarm\n");
        else
                dbg(DBG_INTR, "De-assert AIS Alarm\n");
}

/*      Control signal change interrupt event
 */
static void
fst_intr_ctlchg(struct fst_card_info *card, struct fst_port_info *port)
{
        int signals;

        signals = FST_RDL(card, v24DebouncedSts[port->index]);

        if (signals & ((port->hwif == X21 || port->hwif == X21D)
                       ? IPSTS_INDICATE : IPSTS_DCD)) {
                if (!netif_carrier_ok(port_to_dev(port))) {
                        dbg(DBG_INTR, "DCD active\n");
                        netif_carrier_on(port_to_dev(port));
                }
        } else {
                if (netif_carrier_ok(port_to_dev(port))) {
                        dbg(DBG_INTR, "DCD lost\n");
                        netif_carrier_off(port_to_dev(port));
                }
        }
}

/*      Log Rx Errors
 */
static void
fst_log_rx_error(struct fst_card_info *card, struct fst_port_info *port,
                 unsigned char dmabits, int rxp, unsigned short len)
{
        struct net_device *dev = port_to_dev(port);

        /* Increment the appropriate error counter
         */
        dev->stats.rx_errors++;
        if (dmabits & RX_OFLO) {
                dev->stats.rx_fifo_errors++;
                dbg(DBG_ASS, "Rx fifo error on card %d port %d buffer %d\n",
                    card->card_no, port->index, rxp);
        }
        if (dmabits & RX_CRC) {
                dev->stats.rx_crc_errors++;
                dbg(DBG_ASS, "Rx crc error on card %d port %d\n",
                    card->card_no, port->index);
        }
        if (dmabits & RX_FRAM) {
                dev->stats.rx_frame_errors++;
                dbg(DBG_ASS, "Rx frame error on card %d port %d\n",
                    card->card_no, port->index);
        }
        if (dmabits == (RX_STP | RX_ENP)) {
                dev->stats.rx_length_errors++;
                dbg(DBG_ASS, "Rx length error (%d) on card %d port %d\n",
                    len, card->card_no, port->index);
        }
}

/*      Rx Error Recovery
 */
static void
fst_recover_rx_error(struct fst_card_info *card, struct fst_port_info *port,
                     unsigned char dmabits, int rxp, unsigned short len)
{
        int i;
        int pi;

        pi = port->index;
        /* Discard buffer descriptors until we see the start of the
         * next frame.  Note that for long frames this could be in
         * a subsequent interrupt.
         */
        i = 0;
        while ((dmabits & (DMA_OWN | RX_STP)) == 0) {
                FST_WRB(card, rxDescrRing[pi][rxp].bits, DMA_OWN);
                rxp = (rxp + 1) % NUM_RX_BUFFER;
                if (++i > NUM_RX_BUFFER) {
                        dbg(DBG_ASS, "intr_rx: Discarding more bufs"
                            " than we have\n");
                        break;
                }
                dmabits = FST_RDB(card, rxDescrRing[pi][rxp].bits);
                dbg(DBG_ASS, "DMA Bits of next buffer was %x\n", dmabits);
        }
        dbg(DBG_ASS, "There were %d subsequent buffers in error\n", i);

        /* Discard the terminal buffer */
        if (!(dmabits & DMA_OWN)) {
                FST_WRB(card, rxDescrRing[pi][rxp].bits, DMA_OWN);
                rxp = (rxp + 1) % NUM_RX_BUFFER;
        }
        port->rxpos = rxp;
}

/*      Rx complete interrupt
 */
static void
fst_intr_rx(struct fst_card_info *card, struct fst_port_info *port)
{
        unsigned char dmabits;
        int pi;
        int rxp;
        int rx_status;
        unsigned short len;
        struct sk_buff *skb;
        struct net_device *dev = port_to_dev(port);

        /* Check we have a buffer to process */
        pi = port->index;
        rxp = port->rxpos;
        dmabits = FST_RDB(card, rxDescrRing[pi][rxp].bits);
        if (dmabits & DMA_OWN) {
                dbg(DBG_RX | DBG_INTR, "intr_rx: No buffer port %d pos %d\n",
                    pi, rxp);
                return;
        }
        if (card->dmarx_in_progress)
                return;

        /* Get buffer length */
        len = FST_RDW(card, rxDescrRing[pi][rxp].mcnt);
        /* Discard the CRC */
        len -= 2;
        if (len == 0) {
                /* This seems to happen on the TE1 interface sometimes
                 * so throw the frame away and log the event.
                 */
                pr_err("Frame received with 0 length. Card %d Port %d\n",
                       card->card_no, port->index);
                /* Return descriptor to card */
                FST_WRB(card, rxDescrRing[pi][rxp].bits, DMA_OWN);

                rxp = (rxp + 1) % NUM_RX_BUFFER;
                port->rxpos = rxp;
                return;
        }

        /* Check buffer length and for other errors. We insist on one packet
         * in one buffer. This simplifies things greatly and since we've
         * allocated 8K it shouldn't be a real world limitation
         */
        dbg(DBG_RX, "intr_rx: %d,%d: flags %x len %d\n", pi, rxp, dmabits, len);
        if (dmabits != (RX_STP | RX_ENP) || len > LEN_RX_BUFFER - 2) {
                fst_log_rx_error(card, port, dmabits, rxp, len);
                fst_recover_rx_error(card, port, dmabits, rxp, len);
                return;
        }

        /* Allocate SKB */
        skb = dev_alloc_skb(len);
        if (!skb) {
                dbg(DBG_RX, "intr_rx: can't allocate buffer\n");

                dev->stats.rx_dropped++;

                /* Return descriptor to card */
                FST_WRB(card, rxDescrRing[pi][rxp].bits, DMA_OWN);

                rxp = (rxp + 1) % NUM_RX_BUFFER;
                port->rxpos = rxp;
                return;
        }

        /* We know the length we need to receive, len.
         * It's not worth using the DMA for reads of less than
         * FST_MIN_DMA_LEN
         */

        if (len < FST_MIN_DMA_LEN || card->family == FST_FAMILY_TXP) {
                memcpy_fromio(skb_put(skb, len),
                              card->mem + BUF_OFFSET(rxBuffer[pi][rxp][0]),
                              len);

                /* Reset buffer descriptor */
                FST_WRB(card, rxDescrRing[pi][rxp].bits, DMA_OWN);

                /* Update stats */
                dev->stats.rx_packets++;
                dev->stats.rx_bytes += len;

                /* Push upstream */
                dbg(DBG_RX, "Pushing frame up the stack\n");
                if (port->mode == FST_RAW)
                        skb->protocol = farsync_type_trans(skb, dev);
                else
                        skb->protocol = hdlc_type_trans(skb, dev);
                rx_status = netif_rx(skb);
                fst_process_rx_status(rx_status, port_to_dev(port)->name);
                if (rx_status == NET_RX_DROP)
                        dev->stats.rx_dropped++;
        } else {
                card->dma_skb_rx = skb;
                card->dma_port_rx = port;
                card->dma_len_rx = len;
                card->dma_rxpos = rxp;
                fst_rx_dma(card, card->rx_dma_handle_card,
                           BUF_OFFSET(rxBuffer[pi][rxp][0]), len);
        }
        if (rxp != port->rxpos) {
                dbg(DBG_ASS, "About to increment rxpos by more than 1\n");
                dbg(DBG_ASS, "rxp = %d rxpos = %d\n", rxp, port->rxpos);
        }
        rxp = (rxp + 1) % NUM_RX_BUFFER;
        port->rxpos = rxp;
}

/*      The bottom half to the ISR
 *
 */

static void
do_bottom_half_tx(struct fst_card_info *card)
{
        struct fst_port_info *port;
        int pi;
        int txq_length;
        struct sk_buff *skb;
        unsigned long flags;
        struct net_device *dev;

        /*  Find a free buffer for the transmit
         *  Step through each port on this card
         */

        dbg(DBG_TX, "do_bottom_half_tx\n");
        for (pi = 0, port = card->ports; pi < card->nports; pi++, port++) {
                if (!port->run)
                        continue;

                dev = port_to_dev(port);
                while (!(FST_RDB(card, txDescrRing[pi][port->txpos].bits) &
                         DMA_OWN) &&
                       !(card->dmatx_in_progress)) {
                        /* There doesn't seem to be a txdone event per-se
                         * We seem to have to deduce it, by checking the DMA_OWN
                         * bit on the next buffer we think we can use
                         */
                        spin_lock_irqsave(&card->card_lock, flags);
                        txq_length = port->txqe - port->txqs;
                        if (txq_length < 0) {
                                /* This is the case where one has wrapped and the
                                 * maths gives us a negative number
                                 */
                                txq_length = txq_length + FST_TXQ_DEPTH;
                        }
                        spin_unlock_irqrestore(&card->card_lock, flags);
                        if (txq_length > 0) {
                                /* There is something to send
                                 */
                                spin_lock_irqsave(&card->card_lock, flags);
                                skb = port->txq[port->txqs];
                                port->txqs++;
                                if (port->txqs == FST_TXQ_DEPTH)
                                        port->txqs = 0;

                                spin_unlock_irqrestore(&card->card_lock, flags);
                                /* copy the data and set the required indicators on the
                                 * card.
                                 */
                                FST_WRW(card, txDescrRing[pi][port->txpos].bcnt,
                                        cnv_bcnt(skb->len));
                                if (skb->len < FST_MIN_DMA_LEN ||
                                    card->family == FST_FAMILY_TXP) {
                                        /* Enqueue the packet with normal io */
                                        memcpy_toio(card->mem +
                                                    BUF_OFFSET(txBuffer[pi]
                                                               [port->
                                                                txpos][0]),
                                                    skb->data, skb->len);
                                        FST_WRB(card,
                                                txDescrRing[pi][port->txpos].
                                                bits,
                                                DMA_OWN | TX_STP | TX_ENP);
                                        dev->stats.tx_packets++;
                                        dev->stats.tx_bytes += skb->len;
                                        netif_trans_update(dev);
                                } else {
                                        /* Or do it through dma */
                                        memcpy(card->tx_dma_handle_host,
                                               skb->data, skb->len);
                                        card->dma_port_tx = port;
                                        card->dma_len_tx = skb->len;
                                        card->dma_txpos = port->txpos;
                                        fst_tx_dma(card,
                                                   card->tx_dma_handle_card,
                                                   BUF_OFFSET(txBuffer[pi]
                                                              [port->txpos][0]),
                                                   skb->len);
                                }
                                if (++port->txpos >= NUM_TX_BUFFER)
                                        port->txpos = 0;
                                /* If we have flow control on, can we now release it?
                                 */
                                if (port->start) {
                                        if (txq_length < fst_txq_low) {
                                                netif_wake_queue(port_to_dev
                                                                 (port));
                                                port->start = 0;
                                        }
                                }
                                dev_kfree_skb(skb);
                        } else {
                                /* Nothing to send so break out of the while loop
                                 */
                                break;
                        }
                }
        }
}

static void
do_bottom_half_rx(struct fst_card_info *card)
{
        struct fst_port_info *port;
        int pi;
        int rx_count = 0;

        /* Check for rx completions on all ports on this card */
        dbg(DBG_RX, "do_bottom_half_rx\n");
        for (pi = 0, port = card->ports; pi < card->nports; pi++, port++) {
                if (!port->run)
                        continue;

                while (!(FST_RDB(card, rxDescrRing[pi][port->rxpos].bits)
                         & DMA_OWN) && !(card->dmarx_in_progress)) {
                        if (rx_count > fst_max_reads) {
                                /* Don't spend forever in receive processing
                                 * Schedule another event
                                 */
                                fst_q_work_item(&fst_work_intq, card->card_no);
                                tasklet_schedule(&fst_int_task);
                                break;  /* Leave the loop */
                        }
                        fst_intr_rx(card, port);
                        rx_count++;
                }
        }
}

/*      The interrupt service routine
 *      Dev_id is our fst_card_info pointer
 */
static irqreturn_t
fst_intr(int dummy, void *dev_id)
{
        struct fst_card_info *card = dev_id;
        struct fst_port_info *port;
        int rdidx;              /* Event buffer indices */
        int wridx;
        int event;              /* Actual event for processing */
        unsigned int dma_intcsr = 0;
        unsigned int do_card_interrupt;
        unsigned int int_retry_count;

        /* Check to see if the interrupt was for this card
         * return if not
         * Note that the call to clear the interrupt is important
         */
        dbg(DBG_INTR, "intr: %d %p\n", card->irq, card);
        if (card->state != FST_RUNNING) {
                pr_err("Interrupt received for card %d in a non running state (%d)\n",
                       card->card_no, card->state);

                /* It is possible to really be running, i.e. we have re-loaded
                 * a running card
                 * Clear and reprime the interrupt source
                 */
                fst_clear_intr(card);
                return IRQ_HANDLED;
        }

        /* Clear and reprime the interrupt source */
        fst_clear_intr(card);

        /* Is the interrupt for this card (handshake == 1)
         */
        do_card_interrupt = 0;
        if (FST_RDB(card, interruptHandshake) == 1) {
                do_card_interrupt += FST_CARD_INT;
                /* Set the software acknowledge */
                FST_WRB(card, interruptHandshake, 0xEE);
        }
        if (card->family == FST_FAMILY_TXU) {
                /* Is it a DMA Interrupt
                 */
                dma_intcsr = inl(card->pci_conf + INTCSR_9054);
                if (dma_intcsr & 0x00200000) {
                        /* DMA Channel 0 (Rx transfer complete)
                         */
                        dbg(DBG_RX, "DMA Rx xfer complete\n");
                        outb(0x8, card->pci_conf + DMACSR0);
                        fst_rx_dma_complete(card, card->dma_port_rx,
                                            card->dma_len_rx, card->dma_skb_rx,
                                            card->dma_rxpos);
                        card->dmarx_in_progress = 0;
                        do_card_interrupt += FST_RX_DMA_INT;
                }
                if (dma_intcsr & 0x00400000) {
                        /* DMA Channel 1 (Tx transfer complete)
                         */
                        dbg(DBG_TX, "DMA Tx xfer complete\n");
                        outb(0x8, card->pci_conf + DMACSR1);
                        fst_tx_dma_complete(card, card->dma_port_tx,
                                            card->dma_len_tx, card->dma_txpos);
                        card->dmatx_in_progress = 0;
                        do_card_interrupt += FST_TX_DMA_INT;
                }
        }

        /* Have we been missing Interrupts
         */
        int_retry_count = FST_RDL(card, interruptRetryCount);
        if (int_retry_count) {
                dbg(DBG_ASS, "Card %d int_retry_count is  %d\n",
                    card->card_no, int_retry_count);
                FST_WRL(card, interruptRetryCount, 0);
        }

        if (!do_card_interrupt)
                return IRQ_HANDLED;

        /* Scehdule the bottom half of the ISR */
        fst_q_work_item(&fst_work_intq, card->card_no);
        tasklet_schedule(&fst_int_task);

        /* Drain the event queue */
        rdidx = FST_RDB(card, interruptEvent.rdindex) & 0x1f;
        wridx = FST_RDB(card, interruptEvent.wrindex) & 0x1f;
        while (rdidx != wridx) {
                event = FST_RDB(card, interruptEvent.evntbuff[rdidx]);
                port = &card->ports[event & 0x03];

                dbg(DBG_INTR, "Processing Interrupt event: %x\n", event);

                switch (event) {
                case TE1_ALMA:
                        dbg(DBG_INTR, "TE1 Alarm intr\n");
                        if (port->run)
                                fst_intr_te1_alarm(card, port);
                        break;

                case CTLA_CHG:
                case CTLB_CHG:
                case CTLC_CHG:
                case CTLD_CHG:
                        if (port->run)
                                fst_intr_ctlchg(card, port);
                        break;

                case ABTA_SENT:
                case ABTB_SENT:
                case ABTC_SENT:
                case ABTD_SENT:
                        dbg(DBG_TX, "Abort complete port %d\n", port->index);
                        break;

                case TXA_UNDF:
                case TXB_UNDF:
                case TXC_UNDF:
                case TXD_UNDF:
                        /* Difficult to see how we'd get this given that we
                         * always load up the entire packet for DMA.
                         */
                        dbg(DBG_TX, "Tx underflow port %d\n", port->index);
                        port_to_dev(port)->stats.tx_errors++;
                        port_to_dev(port)->stats.tx_fifo_errors++;
                        dbg(DBG_ASS, "Tx underflow on card %d port %d\n",
                            card->card_no, port->index);
                        break;

                case INIT_CPLT:
                        dbg(DBG_INIT, "Card init OK intr\n");
                        break;

                case INIT_FAIL:
                        dbg(DBG_INIT, "Card init FAILED intr\n");
                        card->state = FST_IFAILED;
                        break;

                default:
                        pr_err("intr: unknown card event %d. ignored\n", event);
                        break;
                }

                /* Bump and wrap the index */
                if (++rdidx >= MAX_CIRBUFF)
                        rdidx = 0;
        }
        FST_WRB(card, interruptEvent.rdindex, rdidx);
        return IRQ_HANDLED;
}

/*      Check that the shared memory configuration is one that we can handle
 *      and that some basic parameters are correct
 */
static void
check_started_ok(struct fst_card_info *card)
{
        int i;

        /* Check structure version and end marker */
        if (FST_RDW(card, smcVersion) != SMC_VERSION) {
                pr_err("Bad shared memory version %d expected %d\n",
                       FST_RDW(card, smcVersion), SMC_VERSION);
                card->state = FST_BADVERSION;
                return;
        }
        if (FST_RDL(card, endOfSmcSignature) != END_SIG) {
                pr_err("Missing shared memory signature\n");
                card->state = FST_BADVERSION;
                return;
        }
        /* Firmware status flag, 0x00 = initialising, 0x01 = OK, 0xFF = fail */
        i = FST_RDB(card, taskStatus);
        if (i == 0x01) {
                card->state = FST_RUNNING;
        } else if (i == 0xFF) {
                pr_err("Firmware initialisation failed. Card halted\n");
                card->state = FST_HALTED;
                return;
        } else if (i != 0x00) {
                pr_err("Unknown firmware status 0x%x\n", i);
                card->state = FST_HALTED;
                return;
        }

        /* Finally check the number of ports reported by firmware against the
         * number we assumed at card detection. Should never happen with
         * existing firmware etc so we just report it for the moment.
         */
        if (FST_RDL(card, numberOfPorts) != card->nports) {
                pr_warn("Port count mismatch on card %d.  Firmware thinks %d we say %d\n",
                        card->card_no,
                        FST_RDL(card, numberOfPorts), card->nports);
        }
}

static int
set_conf_from_info(struct fst_card_info *card, struct fst_port_info *port,
                   struct fstioc_info *info)
{
        int err;
        unsigned char my_framing;

        /* Set things according to the user set valid flags
         * Several of the old options have been invalidated/replaced by the
         * generic hdlc package.
         */
        err = 0;
        if (info->valid & FSTVAL_PROTO) {
                if (info->proto == FST_RAW)
                        port->mode = FST_RAW;
                else
                        port->mode = FST_GEN_HDLC;
        }

        if (info->valid & FSTVAL_CABLE)
                err = -EINVAL;

        if (info->valid & FSTVAL_SPEED)
                err = -EINVAL;

        if (info->valid & FSTVAL_PHASE)
                FST_WRB(card, portConfig[port->index].invertClock,
                        info->invertClock);
        if (info->valid & FSTVAL_MODE)
                FST_WRW(card, cardMode, info->cardMode);
        if (info->valid & FSTVAL_TE1) {
                FST_WRL(card, suConfig.dataRate, info->lineSpeed);
                FST_WRB(card, suConfig.clocking, info->clockSource);
                my_framing = FRAMING_E1;
                if (info->framing == E1)
                        my_framing = FRAMING_E1;
                if (info->framing == T1)
                        my_framing = FRAMING_T1;
                if (info->framing == J1)
                        my_framing = FRAMING_J1;
                FST_WRB(card, suConfig.framing, my_framing);
                FST_WRB(card, suConfig.structure, info->structure);
                FST_WRB(card, suConfig.interface, info->interface);
                FST_WRB(card, suConfig.coding, info->coding);
                FST_WRB(card, suConfig.lineBuildOut, info->lineBuildOut);
                FST_WRB(card, suConfig.equalizer, info->equalizer);
                FST_WRB(card, suConfig.transparentMode, info->transparentMode);
                FST_WRB(card, suConfig.loopMode, info->loopMode);
                FST_WRB(card, suConfig.range, info->range);
                FST_WRB(card, suConfig.txBufferMode, info->txBufferMode);
                FST_WRB(card, suConfig.rxBufferMode, info->rxBufferMode);
                FST_WRB(card, suConfig.startingSlot, info->startingSlot);
                FST_WRB(card, suConfig.losThreshold, info->losThreshold);
                if (info->idleCode)
                        FST_WRB(card, suConfig.enableIdleCode, 1);
                else
                        FST_WRB(card, suConfig.enableIdleCode, 0);
                FST_WRB(card, suConfig.idleCode, info->idleCode);
#if FST_DEBUG
                if (info->valid & FSTVAL_TE1) {
                        printk("Setting TE1 data\n");
                        printk("Line Speed = %d\n", info->lineSpeed);
                        printk("Start slot = %d\n", info->startingSlot);
                        printk("Clock source = %d\n", info->clockSource);
                        printk("Framing = %d\n", my_framing);
                        printk("Structure = %d\n", info->structure);
                        printk("interface = %d\n", info->interface);
                        printk("Coding = %d\n", info->coding);
                        printk("Line build out = %d\n", info->lineBuildOut);
                        printk("Equaliser = %d\n", info->equalizer);
                        printk("Transparent mode = %d\n",
                               info->transparentMode);
                        printk("Loop mode = %d\n", info->loopMode);
                        printk("Range = %d\n", info->range);
                        printk("Tx Buffer mode = %d\n", info->txBufferMode);
                        printk("Rx Buffer mode = %d\n", info->rxBufferMode);
                        printk("LOS Threshold = %d\n", info->losThreshold);
                        printk("Idle Code = %d\n", info->idleCode);
                }
#endif
        }
#if FST_DEBUG
        if (info->valid & FSTVAL_DEBUG)
                fst_debug_mask = info->debug;
#endif

        return err;
}

static void
gather_conf_info(struct fst_card_info *card, struct fst_port_info *port,
                 struct fstioc_info *info)
{
        int i;

        memset(info, 0, sizeof(struct fstioc_info));

        i = port->index;
        info->kernelVersion = LINUX_VERSION_CODE;
        info->nports = card->nports;
        info->type = card->type;
        info->state = card->state;
        info->proto = FST_GEN_HDLC;
        info->index = i;
#if FST_DEBUG
        info->debug = fst_debug_mask;
#endif

        /* Only mark information as valid if card is running.
         * Copy the data anyway in case it is useful for diagnostics
         */
        info->valid = ((card->state == FST_RUNNING) ? FSTVAL_ALL : FSTVAL_CARD)
#if FST_DEBUG
            | FSTVAL_DEBUG
#endif
            ;

        info->lineInterface = FST_RDW(card, portConfig[i].lineInterface);
        info->internalClock = FST_RDB(card, portConfig[i].internalClock);
        info->lineSpeed = FST_RDL(card, portConfig[i].lineSpeed);
        info->invertClock = FST_RDB(card, portConfig[i].invertClock);
        info->v24IpSts = FST_RDL(card, v24IpSts[i]);
        info->v24OpSts = FST_RDL(card, v24OpSts[i]);
        info->clockStatus = FST_RDW(card, clockStatus[i]);
        info->cableStatus = FST_RDW(card, cableStatus);
        info->cardMode = FST_RDW(card, cardMode);
        info->smcFirmwareVersion = FST_RDL(card, smcFirmwareVersion);

        /* The T2U can report cable presence for both A or B
         * in bits 0 and 1 of cableStatus.  See which port we are and
         * do the mapping.
         */
        if (card->family == FST_FAMILY_TXU) {
                if (port->index == 0) {
                        /* Port A
                         */
                        info->cableStatus = info->cableStatus & 1;
                } else {
                        /* Port B
                         */
                        info->cableStatus = info->cableStatus >> 1;
                        info->cableStatus = info->cableStatus & 1;
                }
        }
        /* Some additional bits if we are TE1
         */
        if (card->type == FST_TYPE_TE1) {
                info->lineSpeed = FST_RDL(card, suConfig.dataRate);
                info->clockSource = FST_RDB(card, suConfig.clocking);
                info->framing = FST_RDB(card, suConfig.framing);
                info->structure = FST_RDB(card, suConfig.structure);
                info->interface = FST_RDB(card, suConfig.interface);
                info->coding = FST_RDB(card, suConfig.coding);
                info->lineBuildOut = FST_RDB(card, suConfig.lineBuildOut);
                info->equalizer = FST_RDB(card, suConfig.equalizer);
                info->loopMode = FST_RDB(card, suConfig.loopMode);
                info->range = FST_RDB(card, suConfig.range);
                info->txBufferMode = FST_RDB(card, suConfig.txBufferMode);
                info->rxBufferMode = FST_RDB(card, suConfig.rxBufferMode);
                info->startingSlot = FST_RDB(card, suConfig.startingSlot);
                info->losThreshold = FST_RDB(card, suConfig.losThreshold);
                if (FST_RDB(card, suConfig.enableIdleCode))
                        info->idleCode = FST_RDB(card, suConfig.idleCode);
                else
                        info->idleCode = 0;
                info->receiveBufferDelay =
                    FST_RDL(card, suStatus.receiveBufferDelay);
                info->framingErrorCount =
                    FST_RDL(card, suStatus.framingErrorCount);
                info->codeViolationCount =
                    FST_RDL(card, suStatus.codeViolationCount);
                info->crcErrorCount = FST_RDL(card, suStatus.crcErrorCount);
                info->lineAttenuation = FST_RDL(card, suStatus.lineAttenuation);
                info->lossOfSignal = FST_RDB(card, suStatus.lossOfSignal);
                info->receiveRemoteAlarm =
                    FST_RDB(card, suStatus.receiveRemoteAlarm);
                info->alarmIndicationSignal =
                    FST_RDB(card, suStatus.alarmIndicationSignal);
        }
}

static int
fst_set_iface(struct fst_card_info *card, struct fst_port_info *port,
              struct if_settings *ifs)
{
        sync_serial_settings sync;
        int i;

        if (ifs->size != sizeof(sync))
                return -ENOMEM;

        if (copy_from_user(&sync, ifs->ifs_ifsu.sync, sizeof(sync)))
                return -EFAULT;

        if (sync.loopback)
                return -EINVAL;

        i = port->index;

        switch (ifs->type) {
        case IF_IFACE_V35:
                FST_WRW(card, portConfig[i].lineInterface, V35);
                port->hwif = V35;
                break;

        case IF_IFACE_V24:
                FST_WRW(card, portConfig[i].lineInterface, V24);
                port->hwif = V24;
                break;

        case IF_IFACE_X21:
                FST_WRW(card, portConfig[i].lineInterface, X21);
                port->hwif = X21;
                break;

        case IF_IFACE_X21D:
                FST_WRW(card, portConfig[i].lineInterface, X21D);
                port->hwif = X21D;
                break;

        case IF_IFACE_T1:
                FST_WRW(card, portConfig[i].lineInterface, T1);
                port->hwif = T1;
                break;

        case IF_IFACE_E1:
                FST_WRW(card, portConfig[i].lineInterface, E1);
                port->hwif = E1;
                break;

        case IF_IFACE_SYNC_SERIAL:
                break;

        default:
                return -EINVAL;
        }

        switch (sync.clock_type) {
        case CLOCK_EXT:
                FST_WRB(card, portConfig[i].internalClock, EXTCLK);
                break;

        case CLOCK_INT:
                FST_WRB(card, portConfig[i].internalClock, INTCLK);
                break;

        default:
                return -EINVAL;
        }
        FST_WRL(card, portConfig[i].lineSpeed, sync.clock_rate);
        return 0;
}

static int
fst_get_iface(struct fst_card_info *card, struct fst_port_info *port,
              struct if_settings *ifs)
{
        sync_serial_settings sync;
        int i;

        /* First check what line type is set, we'll default to reporting X.21
         * if nothing is set as IF_IFACE_SYNC_SERIAL implies it can't be
         * changed
         */
        switch (port->hwif) {
        case E1:
                ifs->type = IF_IFACE_E1;
                break;
        case T1:
                ifs->type = IF_IFACE_T1;
                break;
        case V35:
                ifs->type = IF_IFACE_V35;
                break;
        case V24:
                ifs->type = IF_IFACE_V24;
                break;
        case X21D:
                ifs->type = IF_IFACE_X21D;
                break;
        case X21:
        default:
                ifs->type = IF_IFACE_X21;
                break;
        }
        if (!ifs->size)
                return 0;       /* only type requested */

        if (ifs->size < sizeof(sync))
                return -ENOMEM;

        i = port->index;
        memset(&sync, 0, sizeof(sync));
        sync.clock_rate = FST_RDL(card, portConfig[i].lineSpeed);
        /* Lucky card and linux use same encoding here */
        sync.clock_type = FST_RDB(card, portConfig[i].internalClock) ==
            INTCLK ? CLOCK_INT : CLOCK_EXT;
        sync.loopback = 0;

        if (copy_to_user(ifs->ifs_ifsu.sync, &sync, sizeof(sync)))
                return -EFAULT;

        ifs->size = sizeof(sync);
        return 0;
}

static int
fst_siocdevprivate(struct net_device *dev, struct ifreq *ifr, void __user *data, int cmd)
{
        struct fst_card_info *card;
        struct fst_port_info *port;
        struct fstioc_write wrthdr;
        struct fstioc_info info;
        unsigned long flags;
        void *buf;

        dbg(DBG_IOCTL, "ioctl: %x, %p\n", cmd, data);

        port = dev_to_port(dev);
        card = port->card;

        if (!capable(CAP_NET_ADMIN))
                return -EPERM;

        switch (cmd) {
        case FSTCPURESET:
                fst_cpureset(card);
                card->state = FST_RESET;
                return 0;

        case FSTCPURELEASE:
                fst_cpurelease(card);
                card->state = FST_STARTING;
                return 0;

        case FSTWRITE:          /* Code write (download) */

                /* First copy in the header with the length and offset of data
                 * to write
                 */
                if (!data)
                        return -EINVAL;

                if (copy_from_user(&wrthdr, data, sizeof(struct fstioc_write)))
                        return -EFAULT;

                /* Sanity check the parameters. We don't support partial writes
                 * when going over the top
                 */
                if (wrthdr.size > FST_MEMSIZE || wrthdr.offset > FST_MEMSIZE ||
                    wrthdr.size + wrthdr.offset > FST_MEMSIZE)
                        return -ENXIO;

                /* Now copy the data to the card. */

                buf = memdup_user(data + sizeof(struct fstioc_write),
                                  wrthdr.size);
                if (IS_ERR(buf))
                        return PTR_ERR(buf);

                memcpy_toio(card->mem + wrthdr.offset, buf, wrthdr.size);
                kfree(buf);

                /* Writes to the memory of a card in the reset state constitute
                 * a download
                 */
                if (card->state == FST_RESET)
                        card->state = FST_DOWNLOAD;

                return 0;

        case FSTGETCONF:

                /* If card has just been started check the shared memory config
                 * version and marker
                 */
                if (card->state == FST_STARTING) {
                        check_started_ok(card);

                        /* If everything checked out enable card interrupts */
                        if (card->state == FST_RUNNING) {
                                spin_lock_irqsave(&card->card_lock, flags);
                                fst_enable_intr(card);
                                FST_WRB(card, interruptHandshake, 0xEE);
                                spin_unlock_irqrestore(&card->card_lock, flags);
                        }
                }

                if (!data)
                        return -EINVAL;

                gather_conf_info(card, port, &info);

                if (copy_to_user(data, &info, sizeof(info)))
                        return -EFAULT;

                return 0;

        case FSTSETCONF:
                /* Most of the settings have been moved to the generic ioctls
                 * this just covers debug and board ident now
                 */

                if (card->state != FST_RUNNING) {
                        pr_err("Attempt to configure card %d in non-running state (%d)\n",
                               card->card_no, card->state);
                        return -EIO;
                }
                if (copy_from_user(&info, data, sizeof(info)))
                        return -EFAULT;

                return set_conf_from_info(card, port, &info);
        default:
                return -EINVAL;
        }
}

static int
fst_ioctl(struct net_device *dev, struct if_settings *ifs)
{
        struct fst_card_info *card;
        struct fst_port_info *port;

        dbg(DBG_IOCTL, "SIOCDEVPRIVATE, %x\n", ifs->type);

        port = dev_to_port(dev);
        card = port->card;

        if (!capable(CAP_NET_ADMIN))
                return -EPERM;

        switch (ifs->type) {
        case IF_GET_IFACE:
                return fst_get_iface(card, port, ifs);

        case IF_IFACE_SYNC_SERIAL:
        case IF_IFACE_V35:
        case IF_IFACE_V24:
        case IF_IFACE_X21:
        case IF_IFACE_X21D:
        case IF_IFACE_T1:
        case IF_IFACE_E1:
                return fst_set_iface(card, port, ifs);

        case IF_PROTO_RAW:
                port->mode = FST_RAW;
                return 0;

        case IF_GET_PROTO:
                if (port->mode == FST_RAW) {
                        ifs->type = IF_PROTO_RAW;
                        return 0;
                }
                return hdlc_ioctl(dev, ifs);

        default:
                port->mode = FST_GEN_HDLC;
                dbg(DBG_IOCTL, "Passing this type to hdlc %x\n",
                    ifs->type);
                return hdlc_ioctl(dev, ifs);
        }
}

static void
fst_openport(struct fst_port_info *port)
{
        int signals;

        /* Only init things if card is actually running. This allows open to
         * succeed for downloads etc.
         */
        if (port->card->state == FST_RUNNING) {
                if (port->run) {
                        dbg(DBG_OPEN, "open: found port already running\n");

                        fst_issue_cmd(port, STOPPORT);
                        port->run = 0;
                }

                fst_rx_config(port);
                fst_tx_config(port);
                fst_op_raise(port, OPSTS_RTS | OPSTS_DTR);

                fst_issue_cmd(port, STARTPORT);
                port->run = 1;

                signals = FST_RDL(port->card, v24DebouncedSts[port->index]);
                if (signals & ((port->hwif == X21 || port->hwif == X21D)
                               ? IPSTS_INDICATE : IPSTS_DCD))
                        netif_carrier_on(port_to_dev(port));
                else
                        netif_carrier_off(port_to_dev(port));

                port->txqe = 0;
                port->txqs = 0;
        }
}

static void
fst_closeport(struct fst_port_info *port)
{
        if (port->card->state == FST_RUNNING) {
                if (port->run) {
                        port->run = 0;
                        fst_op_lower(port, OPSTS_RTS | OPSTS_DTR);

                        fst_issue_cmd(port, STOPPORT);
                } else {
                        dbg(DBG_OPEN, "close: port not running\n");
                }
        }
}

static int
fst_open(struct net_device *dev)
{
        int err;
        struct fst_port_info *port;

        port = dev_to_port(dev);
        if (!try_module_get(THIS_MODULE))
                return -EBUSY;

        if (port->mode != FST_RAW) {
                err = hdlc_open(dev);
                if (err) {
                        module_put(THIS_MODULE);
                        return err;
                }
        }

        fst_openport(port);
        netif_wake_queue(dev);
        return 0;
}

static int
fst_close(struct net_device *dev)
{
        struct fst_port_info *port;
        struct fst_card_info *card;
        unsigned char tx_dma_done;
        unsigned char rx_dma_done;

        port = dev_to_port(dev);
        card = port->card;

        tx_dma_done = inb(card->pci_conf + DMACSR1);
        rx_dma_done = inb(card->pci_conf + DMACSR0);
        dbg(DBG_OPEN,
            "Port Close: tx_dma_in_progress = %d (%x) rx_dma_in_progress = %d (%x)\n",
            card->dmatx_in_progress, tx_dma_done, card->dmarx_in_progress,
            rx_dma_done);

        netif_stop_queue(dev);
        fst_closeport(dev_to_port(dev));
        if (port->mode != FST_RAW)
                hdlc_close(dev);

        module_put(THIS_MODULE);
        return 0;
}

static int
fst_attach(struct net_device *dev, unsigned short encoding, unsigned short parity)
{
        /* Setting currently fixed in FarSync card so we check and forget
         */
        if (encoding != ENCODING_NRZ || parity != PARITY_CRC16_PR1_CCITT)
                return -EINVAL;
        return 0;
}

static void
fst_tx_timeout(struct net_device *dev, unsigned int txqueue)
{
        struct fst_port_info *port;
        struct fst_card_info *card;

        port = dev_to_port(dev);
        card = port->card;
        dev->stats.tx_errors++;
        dev->stats.tx_aborted_errors++;
        dbg(DBG_ASS, "Tx timeout card %d port %d\n",
            card->card_no, port->index);
        fst_issue_cmd(port, ABORTTX);

        netif_trans_update(dev);
        netif_wake_queue(dev);
        port->start = 0;
}

static netdev_tx_t
fst_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct fst_card_info *card;
        struct fst_port_info *port;
        unsigned long flags;
        int txq_length;

        port = dev_to_port(dev);
        card = port->card;
        dbg(DBG_TX, "fst_start_xmit: length = %d\n", skb->len);

        /* Drop packet with error if we don't have carrier */
        if (!netif_carrier_ok(dev)) {
                dev_kfree_skb(skb);
                dev->stats.tx_errors++;
                dev->stats.tx_carrier_errors++;
                dbg(DBG_ASS,
                    "Tried to transmit but no carrier on card %d port %d\n",
                    card->card_no, port->index);
                return NETDEV_TX_OK;
        }

        /* Drop it if it's too big! MTU failure ? */
        if (skb->len > LEN_TX_BUFFER) {
                dbg(DBG_ASS, "Packet too large %d vs %d\n", skb->len,
                    LEN_TX_BUFFER);
                dev_kfree_skb(skb);
                dev->stats.tx_errors++;
                return NETDEV_TX_OK;
        }

        /* We are always going to queue the packet
         * so that the bottom half is the only place we tx from
         * Check there is room in the port txq
         */
        spin_lock_irqsave(&card->card_lock, flags);
        txq_length = port->txqe - port->txqs;
        if (txq_length < 0) {
                /* This is the case where the next free has wrapped but the
                 * last used hasn't
                 */
                txq_length = txq_length + FST_TXQ_DEPTH;
        }
        spin_unlock_irqrestore(&card->card_lock, flags);
        if (txq_length > fst_txq_high) {
                /* We have got enough buffers in the pipeline.  Ask the network
                 * layer to stop sending frames down
                 */
                netif_stop_queue(dev);
                port->start = 1;        /* I'm using this to signal stop sent up */
        }

        if (txq_length == FST_TXQ_DEPTH - 1) {
                /* This shouldn't have happened but such is life
                 */
                dev_kfree_skb(skb);
                dev->stats.tx_errors++;
                dbg(DBG_ASS, "Tx queue overflow card %d port %d\n",
                    card->card_no, port->index);
                return NETDEV_TX_OK;
        }

        /* queue the buffer
         */
        spin_lock_irqsave(&card->card_lock, flags);
        port->txq[port->txqe] = skb;
        port->txqe++;
        if (port->txqe == FST_TXQ_DEPTH)
                port->txqe = 0;
        spin_unlock_irqrestore(&card->card_lock, flags);

        /* Scehdule the bottom half which now does transmit processing */
        fst_q_work_item(&fst_work_txq, card->card_no);
        tasklet_schedule(&fst_tx_task);

        return NETDEV_TX_OK;
}

/*      Card setup having checked hardware resources.
 *      Should be pretty bizarre if we get an error here (kernel memory
 *      exhaustion is one possibility). If we do see a problem we report it
 *      via a printk and leave the corresponding interface and all that follow
 *      disabled.
 */
static char *type_strings[] = {
        "no hardware",          /* Should never be seen */
        "FarSync T2P",
        "FarSync T4P",
        "FarSync T1U",
        "FarSync T2U",
        "FarSync T4U",
        "FarSync TE1"
};

static int
fst_init_card(struct fst_card_info *card)
{
        int i;
        int err;

        /* We're working on a number of ports based on the card ID. If the
         * firmware detects something different later (should never happen)
         * we'll have to revise it in some way then.
         */
        for (i = 0; i < card->nports; i++) {
                err = register_hdlc_device(card->ports[i].dev);
                if (err < 0) {
                        pr_err("Cannot register HDLC device for port %d (errno %d)\n",
                               i, -err);
                        while (i--)
                                unregister_hdlc_device(card->ports[i].dev);
                        return err;
                }
        }

        pr_info("%s-%s: %s IRQ%d, %d ports\n",
                port_to_dev(&card->ports[0])->name,
                port_to_dev(&card->ports[card->nports - 1])->name,
                type_strings[card->type], card->irq, card->nports);
        return 0;
}

static const struct net_device_ops fst_ops = {
        .ndo_open       = fst_open,
        .ndo_stop       = fst_close,
        .ndo_start_xmit = hdlc_start_xmit,
        .ndo_siocwandev = fst_ioctl,
        .ndo_siocdevprivate = fst_siocdevprivate,
        .ndo_tx_timeout = fst_tx_timeout,
};

/*      Initialise card when detected.
 *      Returns 0 to indicate success, or errno otherwise.
 */
static int
fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        static int no_of_cards_added;
        struct fst_card_info *card;
        int err = 0;
        int i;

        printk_once(KERN_INFO
                    pr_fmt("FarSync WAN driver " FST_USER_VERSION
                           " (c) 2001-2004 FarSite Communications Ltd.\n"));
#if FST_DEBUG
        dbg(DBG_ASS, "The value of debug mask is %x\n", fst_debug_mask);
#endif
        /* We are going to be clever and allow certain cards not to be
         * configured.  An exclude list can be provided in /etc/modules.conf
         */
        if (fst_excluded_cards != 0) {
                /* There are cards to exclude
                 *
                 */
                for (i = 0; i < fst_excluded_cards; i++) {
                        if (pdev->devfn >> 3 == fst_excluded_list[i]) {
                                pr_info("FarSync PCI device %d not assigned\n",
                                        (pdev->devfn) >> 3);
                                return -EBUSY;
                        }
                }
        }

        /* Allocate driver private data */
        card = kzalloc_obj(struct fst_card_info);
        if (!card)
                return -ENOMEM;

        /* Try to enable the device */
        err = pci_enable_device(pdev);
        if (err) {
                pr_err("Failed to enable card. Err %d\n", -err);
                goto enable_fail;
        }

        err = pci_request_regions(pdev, "FarSync");
        if (err) {
                pr_err("Failed to allocate regions. Err %d\n", -err);
                goto regions_fail;
        }

        /* Get virtual addresses of memory regions */
        card->pci_conf = pci_resource_start(pdev, 1);
        card->phys_mem = pci_resource_start(pdev, 2);
        card->phys_ctlmem = pci_resource_start(pdev, 3);
        card->mem = ioremap(card->phys_mem, FST_MEMSIZE);
        if (!card->mem) {
                pr_err("Physical memory remap failed\n");
                err = -ENODEV;
                goto ioremap_physmem_fail;
        }
        card->ctlmem = ioremap(card->phys_ctlmem, 0x10);
        if (!card->ctlmem) {
                pr_err("Control memory remap failed\n");
                err = -ENODEV;
                goto ioremap_ctlmem_fail;
        }
        dbg(DBG_PCI, "kernel mem %p, ctlmem %p\n", card->mem, card->ctlmem);

        /* Register the interrupt handler */
        if (request_irq(pdev->irq, fst_intr, IRQF_SHARED, FST_DEV_NAME, card)) {
                pr_err("Unable to register interrupt %d\n", card->irq);
                err = -ENODEV;
                goto irq_fail;
        }

        /* Record info we need */
        card->irq = pdev->irq;
        card->type = ent->driver_data;
        card->family = ((ent->driver_data == FST_TYPE_T2P) ||
                        (ent->driver_data == FST_TYPE_T4P))
            ? FST_FAMILY_TXP : FST_FAMILY_TXU;
        if (ent->driver_data == FST_TYPE_T1U ||
            ent->driver_data == FST_TYPE_TE1)
                card->nports = 1;
        else
                card->nports = ((ent->driver_data == FST_TYPE_T2P) ||
                                (ent->driver_data == FST_TYPE_T2U)) ? 2 : 4;

        card->state = FST_UNINIT;
        spin_lock_init(&card->card_lock);

        for (i = 0; i < card->nports; i++) {
                struct net_device *dev = alloc_hdlcdev(&card->ports[i]);
                hdlc_device *hdlc;

                if (!dev) {
                        while (i--)
                                free_netdev(card->ports[i].dev);
                        pr_err("FarSync: out of memory\n");
                        err = -ENOMEM;
                        goto hdlcdev_fail;
                }
                card->ports[i].dev    = dev;
                card->ports[i].card   = card;
                card->ports[i].index  = i;
                card->ports[i].run    = 0;

                hdlc = dev_to_hdlc(dev);

                /* Fill in the net device info */
                /* Since this is a PCI setup this is purely
                 * informational. Give them the buffer addresses
                 * and basic card I/O.
                 */
                dev->mem_start   = card->phys_mem
                                + BUF_OFFSET(txBuffer[i][0][0]);
                dev->mem_end     = card->phys_mem
                                + BUF_OFFSET(txBuffer[i][NUM_TX_BUFFER - 1][LEN_RX_BUFFER - 1]);
                dev->base_addr   = card->pci_conf;
                dev->irq         = card->irq;

                dev->netdev_ops = &fst_ops;
                dev->tx_queue_len = FST_TX_QUEUE_LEN;
                dev->watchdog_timeo = FST_TX_TIMEOUT;
                hdlc->attach = fst_attach;
                hdlc->xmit   = fst_start_xmit;
        }

        card->device = pdev;

        dbg(DBG_PCI, "type %d nports %d irq %d\n", card->type,
            card->nports, card->irq);
        dbg(DBG_PCI, "conf %04x mem %08x ctlmem %08x\n",
            card->pci_conf, card->phys_mem, card->phys_ctlmem);

        /* Reset the card's processor */
        fst_cpureset(card);
        card->state = FST_RESET;

        /* Initialise DMA (if required) */
        fst_init_dma(card);

        /* Record driver data for later use */
        pci_set_drvdata(pdev, card);

        /* Remainder of card setup */
        if (no_of_cards_added >= FST_MAX_CARDS) {
                pr_err("FarSync: too many cards\n");
                err = -ENOMEM;
                goto card_array_fail;
        }
        fst_card_array[no_of_cards_added] = card;
        card->card_no = no_of_cards_added++;    /* Record instance and bump it */
        err = fst_init_card(card);
        if (err)
                goto init_card_fail;
        if (card->family == FST_FAMILY_TXU) {
                /* Allocate a dma buffer for transmit and receives
                 */
                card->rx_dma_handle_host =
                    dma_alloc_coherent(&card->device->dev, FST_MAX_MTU,
                                       &card->rx_dma_handle_card, GFP_KERNEL);
                if (!card->rx_dma_handle_host) {
                        pr_err("Could not allocate rx dma buffer\n");
                        err = -ENOMEM;
                        goto rx_dma_fail;
                }
                card->tx_dma_handle_host =
                    dma_alloc_coherent(&card->device->dev, FST_MAX_MTU,
                                       &card->tx_dma_handle_card, GFP_KERNEL);
                if (!card->tx_dma_handle_host) {
                        pr_err("Could not allocate tx dma buffer\n");
                        err = -ENOMEM;
                        goto tx_dma_fail;
                }
        }
        return 0;               /* Success */

tx_dma_fail:
        dma_free_coherent(&card->device->dev, FST_MAX_MTU,
                          card->rx_dma_handle_host, card->rx_dma_handle_card);
rx_dma_fail:
        fst_disable_intr(card);
        for (i = 0 ; i < card->nports ; i++)
                unregister_hdlc_device(card->ports[i].dev);
init_card_fail:
        fst_card_array[card->card_no] = NULL;
card_array_fail:
        for (i = 0 ; i < card->nports ; i++)
                free_netdev(card->ports[i].dev);
hdlcdev_fail:
        free_irq(card->irq, card);
irq_fail:
        iounmap(card->ctlmem);
ioremap_ctlmem_fail:
        iounmap(card->mem);
ioremap_physmem_fail:
        pci_release_regions(pdev);
regions_fail:
        pci_disable_device(pdev);
enable_fail:
        kfree(card);
        return err;
}

/*      Cleanup and close down a card
 */
static void
fst_remove_one(struct pci_dev *pdev)
{
        struct fst_card_info *card;
        int i;

        card = pci_get_drvdata(pdev);

        for (i = 0; i < card->nports; i++) {
                struct net_device *dev = port_to_dev(&card->ports[i]);

                unregister_hdlc_device(dev);
                free_netdev(dev);
        }

        fst_disable_intr(card);
        free_irq(card->irq, card);
        tasklet_kill(&fst_tx_task);
        tasklet_kill(&fst_int_task);

        iounmap(card->ctlmem);
        iounmap(card->mem);
        pci_release_regions(pdev);
        if (card->family == FST_FAMILY_TXU) {
                /* Free dma buffers
                 */
                dma_free_coherent(&card->device->dev, FST_MAX_MTU,
                                  card->rx_dma_handle_host,
                                  card->rx_dma_handle_card);
                dma_free_coherent(&card->device->dev, FST_MAX_MTU,
                                  card->tx_dma_handle_host,
                                  card->tx_dma_handle_card);
        }
        fst_card_array[card->card_no] = NULL;
        kfree(card);
}

static struct pci_driver fst_driver = {
        .name           = FST_NAME,
        .id_table       = fst_pci_dev_id,
        .probe          = fst_add_one,
        .remove         = fst_remove_one,
};

static int __init
fst_init(void)
{
        int i;

        for (i = 0; i < FST_MAX_CARDS; i++)
                fst_card_array[i] = NULL;
        return pci_register_driver(&fst_driver);
}

static void __exit
fst_cleanup_module(void)
{
        pr_info("FarSync WAN driver unloading\n");
        pci_unregister_driver(&fst_driver);
}

module_init(fst_init);
module_exit(fst_cleanup_module);